United States Office of Air Quality
Environmental Protection Planning and Standards
Agency Research Triangle Park NC 27711
EPA-453/R-93-032
July 1993
Air
&EPA Alternative Control
Techniques Document -
NOx Emissions from
Stationary Reciprocating
Internal Combustion
Engines
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EPA-453/R-93-032
—4
Alternative Control
Techniques Document—
NOX Emissions from Stationary
Reciprocating Internal Combustion Engines
Emission Standards Division
U. S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
July 1993
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ALTERNATIVE CONTROL TECHNIQUES DOCUMENTS
This report is issued by the Emission Standards Division,
Office of Air Quality Planning and Standards, U. S. Environmental
Protection Agency, to provide information to State and local air
pollution control agencies. Mention of trade names and
commercial products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available--as
supplies permit—from the Library Services Office (MD-35),
U. S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711 ([919] 541-2777) or, for a nominal fee,
from the National Technical Information Services, 5285 Port Royal
Road, Springfield, Virginia 22161 ([800] 553-NTIS).
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TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1-1
2.0 SUMMARY 2-1
2.1 UNCONTROLLED NO EMISSIONS 2-2
2.2 CONTROL TECHNIQUES AND ACHIEVABLE NOX EMISSION
REDUCTIONS 2-4
2.2.1 Control Techniques for Rich-Burn SI
Engines 2-5
2.2.2 Control Techniques for Lean-Burn SI
Engines 2-12
2.2.3 Control Techniques for Diesel and
Dual-Fuel CI Engines 2-18
2.3 CONTROL TECHNIQUES COSTS AND COST EFFECTIVENESS 2-25
2.3.1 Costs and Cost Effectiveness for
Rich-Burn SI Engines 2-26
2.3.2 Costs and Cost Effectiveness for
Lean-Burn SI Engines 2-32
2.3.3 Costs and Cost Effectiveness for Diesel
Engines 2-38
2.3.4 Costs and Cost Effectiveness for
Dual-Fuel Engines 2-38
3.0 DESCRIPTION OF INTERNAL COMBUSTION ENGINES
AND INDUSTRY APPLICATIONS 3-1
3.1 OPERATING DESIGN CONSIDERATIONS 3-2
3.1.1 Ignition Methods 3-2
3.1.2 Operating Cycles 3-3
3.1.3 Charging Methods 3-5
3.2 TYPES OF FUEL 3-10
3.2.1 Spark-Ignited Engines 3-10
3.2.2 Compression-Ignited Engines '3-10
3.3 INDUSTRY APPLICATIONS 3-11
3.3.1 Engine Sizes 3-12
3.3.2 Oil and Gas Industry 3-13
3.3.3 General Industrial and Municipal Usage . 3-15
3.3.4 Agricultural Usage 3-15
3.3.5 Electric Power Generation 3-18
3.4 REFERENCES 3-20
4.0 CHARACTERIZATION OF NO EMISSIONS 4-1
4.1 FORMATION OF EMISSIONS 4-1
4.1.1 The Formation of NO,. 4-1
4.1.2 Formation of Other Emissions 4-3
4.2 FACTORS THAT INFLUENCE NO EMISSIONS 4-4
4.2.1 Engine Design and Operating Parameters . 4-4
4.2.2 Fuel Effects 4-8
4.2.3 Ambient Conditions 4-10
4.3 UNCONTROLLED EMISSION LEVELS 4-10
4.4 REFERENCES FOR CHAPTER 4 4-13
iii
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TABLE OF CONTENTS (continued)
Page
5.0 NO CONTROL TECHNIQUES 5-1
5.1 NOX CONTROL TECHNIQUES FOR RICH-BURN ENGINES . 5-2
5.1.1 Adjustment of A/F in Rich-Burn Engines . 5-3
5.1.2 Adjustment of Ignition Timing in
Rich-Burn Engines 5-8
5.1.3 Combination of A/F Adjustment and
Ignition Timing Retard 5-13
5.1.4 Prestratified Charge (PSC®) 5-14
5.1.5 Nonselective Catalytic Reduction .... 5-23
5.1.6 Low-Emission Combustion 5-32
5.2 NOX CONTROL TECHNIQUES FOR LEAN-BURN SI ENGINES 5-41
5.2.1 Adjustments to the A/F for Lean-Burn
Engines 5-41
5.2.2 Ignition Timing Retard 5-49
5.2.3 Combination of A/F and Ignition Retard . 5-53
5.2.4 Selective Catalytic Reduction 5-55
5.2.5 Low-Emission Combustion 5-65
5.3 NO CONTROL TECHNIQUES FOR CI ENGINES 5-69
5.3.1 Diesel Engines 5-70
5.3.2 Dual-Fuel Engines 5-76
5.4 OTHER NOX CONTROL TECHNIQUES 5-85
5.4.1 Intake Air Cooling 5-85
5.4.2 Exhaust Gas Recirculation 5-85
5.4.3 Power Output Derate 5-86
5.4.4 Water Injection 5-86
5.4.5 Water/Fuel Emulsions 5-86
5.4.6 Alternate Fuels 5-86
5.5 REFERENCES 5-87
6.0 CONTROL COSTS 6-1
6.1 COST EVALUATION METHODOLOGY 6-1
6.1.1 Capital Cost Estimation 6-2
6.1.2 Annual Costs 6-4
6.1.3 Cost Effectiveness 6-9
6.2 CONTROL COSTS FOR RICH-BURN SI ENGINES .... 6-9
6.2.1 Control Costs for A/F Adjustment .... 6-9
6.2.2 Control Costs for Ignition Timing Retard 6-13
6.2.3 Control Costs For Combination of A/F
Adjustment and Ignition Timing Retard 6-17
6.2.4 Control Costs for Prestratified Charge
(PSC«) 6-20
6.2.5 Control Costs for Nonselective Catalytic
Reduction (NSCR) 6-27
6.2.6 Control Costs for Conversion to
Low-Emission Combustion 6-30
6.3 CONTROL COSTS FOR LEAN-BURN SI ENGINES .... 6-39
6.3.1 Control Costs for A/F Adjustment .... 6-39
6.3.2 Control Costs for Ignition Timing Retard 6-44
iv
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TABLE OF CONTENTS (continued)
Page
6.3.3 Control Costs for A/F Adjustment and
Ignition Timing Retard 6-46
6.3.4 Control Costs for SCR Applied to
Lean-Burn SI Engines 6-50
6.3.5 Control Costs for Conversion to
Low-Emission Combustion 6-56
6.4 CONTROL COSTS FOR COMPRESSION IGNITION (CD
ENGINES 6-57
6.4.1 Control Costs For Injection Timing Retard 6-57
6.4.2 Control Costs for Conversion to
Low-Emission Combustion 6-68
6.5 REFERENCES FOR CHAPTER 6 6-71
7.0 ENVIRONMENTAL AND ENERGY IMPACTS 7-1
7.1 AIR POLLUTION 7-1
7.1.1 NOX Emission Reductions for Rich-Burn SI
Engines 7-1
7.1.2 NO Emission Reductions for Lean-Burn SI
Engines 7-2
7.1.3 NO Emission Reductions for Diesel CI
Engines 7-2
7.1.4 NO Emission Reductions for Dual-Fuel CI
Engines 7-7
7.1.5 Emissions Trade-offs 7-7
7.2 SOLID WASTE DISPOSAL 7-11
7.3 ENERGY CONSUMPTION 7-11
7.4 REFERENCES FOR CHAPTER 7 7-13
APPENDIX A
APPENDIX B
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LIST OF FIGURES
Page
Figure 2-1. Total capital costs for NOX control
techniques supplied to rich-burn
SI engines 2-27
Figure 2-2. Total annual costs for NOX control techniques
applied to rich-burn SI engines
(8,000 hr/yr) 2-28
Figure 2-3. Cost effectiveness for NOX control techniques
applied to rich-burn engines
(8,000 hr/yr) 2-29
Figure 2-4. Total capital costs for NOX control
techniques applied to lean-burn
SI engines 2-33
Figure 2-5. Total annual costs for NO., control techniques
applied to lean-burn SI engines
(8,000 hr/yr) 2-34
Figure 2-6. Cost effectiveness for NO., control techniques
applied to lean-burn SI engines
(8,000 hr/yr) 2-35
Figure 2-7. Total capital costs for NOX control
techniques applied to diesel engines. . 2-39
Figure 2-8. Total annual costs for NOX control techniques
applied to diesel engines (8,000 hr/yr) 2-40
Figure 2-9. Cost effectiveness for NO^ control techniques
applied to diesel engines (8,000 hr/yr) 2-41
Figure 2-10. Total capital costs for NOX control
techniques applied to dual-fuel engines 2-43
Figure 2-11. Total annual costs for NOX control techniques
applied to dual-fuel engines
(8,000 hr/yr) 2-44
Figure 2-12. Cost effectiveness for NOX control techniques
applied to dual-free engines
(8,000 hr/yr)
2-45
VI
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Figure 3-1
LIST OF FIGURES (continued)
Two-stroke, compression ignition
(blower-scavenged) 1C engine cycle. Two
strokes of 180° each of crankshaft
rotation, or 360° rotation per cycle . .
Page
3-4
Figure 3-2. The four-stroke, spark ignition 1C engine
cycle. Four strokes of 180° each of
crankshaft rotation, or 720° of rotation
per cycle 3-6
Figure 3-3. Turbocharged, intercooled, large-bore
1C engine 3-9
Figure 4-1. Effect of air/fuel ratio on NOX, CO, and HC
emissions 4-5
Figure 4-2. Impact of different fuels on NOX and CO
emissions 4-9
Figure 5-1. The effect of air-to-fuel ratio on NOX,
CO, and HC emissions 5-4
Figure 5-2. Parametric adjustments and the effect of
ignition timing retard for a rich-burn
engine model 5-11
Figure 5-3. Parametric adjustments and the effect of
ignition timing retard for a second
rich-burn engine model 5-12
Figure 5-4. Stratification of the air/fuel charge using
a prestratified charge control system . 5-15
Figure 5-5. Schematic of a prestratified charge system . 5-16
Figure 5-6. Schematic of a nonselective catalytic
reduction system design with a single
catalytic reactor 5-25
Figure 5-7. Schematic of a nonselective catalytic
reduction system design with two
catalytic reactors 5-26
Figure 5-8. Low-emission engine combustion chamber
configurations 5-33
Figure 5-9. Low-emission engine combustion chamber with
a precombustion chamber 5-34
VI1
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LIST OF FIGURES (continued)
Page
Figure 5-10. The effect of A/F adjustment on NOX
emissions for two lean-burn engine
models 5-44
Figure 5-11. The effect of A/F adjustment on NOX
emissions for four identical lean-burn
engines 5-46
Figure 5-12. The effect of A/F adjustment on emissions and
fuel efficiency for a lean-burn engine . 5-48
Figure 5-13. The effect of ignition timing retard on NOX
emissions for four identical
lean-burn engines. 6 5-50
Figure 5-14. The effect of ignition timing on emissions
and fuel efficiency for a lean-burn
engine 5-52
Figure 5-15. Schematic of a selective catalytic
reduction system 5-56
Figure 5-16. Cutaway view of a honeycomb catalyst
configuration 5-57
Figure 6-1. Total capital and annual costs and cost
effectiveness for A/F adjustment in
rich-burn engines, based on installation
of an automatic A/F adjustment system and
controls ,6-12
Figure 6-2. Total capital and annual costs and cost
effectiveness for ignition timing retard
in rich-burn engines, based on
installation of an electronic ignition
system 6-15
Figure 6-3. Total capital and annual costs and cost
effectiveness for A/F adjustment and
ignition timing retard in rich-burn
engines, based on installation of
automatic A/F adjustment system and
controls and an electronic ignition
system 6-19
viii
-------
LIST OF FIGURES (continued)
Page
Figure 6-4.
Figure 6-5.
Figure 6-6.
Figure 6-7.
Figure 6-8.
Figure 6-9.
Purchased equipment costs (including controls
and installation) estimated by vendor for
PSC® installations, with and without
turbocharger modification/addition . . .
Total capital and annual costs and cost
effectiveness for PSC® in rich-burn
engines, without turbocharger
installation or modification
6-22
6-23
Total capital and annual costs and cost
effectiveness for PSC® in rich-burn
engines, with turbocharger installation
or modification
Total capital and annual costs and cost
effectiveness for nonselective catalytic
reduction for rich-burn engines
Hardware costs estimated by engine
manufacturers for retrofit to
low-emission combustion for medium-speed,
SI engines
Hardware costs estimated by one engine
manufacturer for retrofit to low-emission
combustion for low-speed engines ....
6-24
6-28
6-32
6-34
Figure 6-10. Total capital and annual costs and cost
effectiveness for retrofit to
low-emission combustion for medium-speed
engines
Figure 6-11. Total capital and annual costs and cost
effectiveness for retrofit to
low-emission combustion for low-speed
engines
6-35
6-36
Figure 6-12. Total capital and annual costs and cost
effectiveness for A/F adjustment in
lean-burn engines, based on the addition
of a new turbocharger to the existing
engine
6-42
IX
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LIST OF FIGURES (continued)
Page
Figure 6-13. Total capital and annual costs and cost
effectiveness for ignition timing retard
in lean-burn SI engines, based on
installation of an electronic ignition
system 6-45
Figure 6 -14. Total capital and annual costs and cost
effectiveness for A/F adjustment and
ignition timing retard in lean-burn SI
engines, based on addition of a new
turbocharger and an electronic ignition
system 6-48
Figure 6-15. Installed costs for selective catalytic
reduction estimated by catalyst vendors
for gas-fired, lean-burn engines .... 6-51
Figure 6-16. Total capital and annual costs and cost
effectiveness for selective catalytic
reduction for lean-burn SI engines,
including a continuous emission
monitoring system 6-53
Figure 6-17. Total capital and annual costs and cost
effectiveness for injection timing retard
in diesel engines, based on installation
of an electronic ignition system. ... 6-58
Figure 6-18. Total capital and annual costs and cost
effectiveness for injection timing retard
in dual-fuel engines, based on
installation of an electronic ignition
system 6-59
Figure 6-19. Installed capital costs for selective
catalytic reduction estimated by catalyst
vendors for diesel and dual-fuel engines 6-62
Figure 6-20. Total capital and annual costs and cost
effectiveness for selective catalytic
reduction for diesel engines, including a
continuous emission monitoring system . 6-64
Figure 6-21. Total capital and annual costs and cost
effectiveness for selective catalytic
reduction for dual-fuel engines,
including a continuous emission
monitoring system 6-65
-------
LIST OF FIGURES (continued)
Page
Figure 6-22. Total capital and annual costs and cost
effectiveness for retrofit to
low-emission combustion for dual-fuel
engines 6-69
XI
-------
LIST OF TABLES
Page
TABLE 2-1. AVERAGE HEAT RATES AND UNCONTROLLED NOX
EMISSION FACTORS FOR RECIPROCATING
ENGINES 2-3
TABLE 2-2. EXPECTED RANGE OF NOX EMISSION REDUCTIONS AND
CONTROLLED EMISSION LEVELS FOR CONTROL
TECHNIQUES APPLIED TO RICH-BURN SI
ENGINES (NATURAL GAS FUEL) 2-6
TABLE 2-3. POTENTIAL NOX REDUCTIONS FOR RICH-BURN
SI ENGINES (NATURAL GAS FUEL) 2-7
TABLE 2-4. EFFECTS OF NOX CONTROL TECHNIQUES ON
RICH-BURN SI ENGINES 2-8
TABLE 2-5. EXPECTED RANGE OF NO EMISSION REDUCTIONS AND
CONTROLLED EMISSION LEVELS FOR CONTROL
TECHNIQUES APPLIED TO LEAN-BURN SI
ENGINES (NATURAL GAS FUEL) 2-13
TABLE 2-6. POTENTIAL NOX REDUCTIONS FOR LEAN-BURN
SI ENGINES 2-14
TABLE 2-7. EFFECTS OF NO CONTROL TECHNIQUES ON
LEAN-BURN SI ENGINES 2-15
TABLE 2-8. EXPECTED RANGE OF NO EMISSION REDUCTIONS AND
CONTROLLED EMISSION LEVELS FOR CONTROL
TECHNIQUES APPLIED TO DIESEL AND
DUAL-FUEL ENGINES 2-19
TABLE 2-9. POTENTIAL NOX REDUCTIONS FOR DIESEL ENGINES . 2-20
TABLE 2-10. POTENTIAL NO REDUCTIONS FOR DUAL-FUEL
ENGINES 2-21
TABLE 2-11. EFFECTS OF NOX CONTROL TECHNIQUES ON
DIESEL AND DUAL-FUEL ENGINES 2-23
TABLE 2-12. COSTS AND COST EFFECTIVENESS SUMMARY FOR NOX
CONTROL TECHNIQUES APPLIED TO RICH-BURN
SI ENGINES 2-30
TABLE 2-13. COSTS AND COST EFFECTIVENESS SUMMARY FOR NOX
CONTROL TECHNIQUES APPLIED TO LEAN-BURN
SI ENGINES 2-36
XI1
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LIST OF TABLES (continued)
Page
TABLE 2-14. COSTS AND COST EFFECTIVENESS SUMMARY FOR NO
CONTROL TECHNIQUES APPLIED TO DIESEL
ENGINES 2-42
TABLE 2-15. COSTS AND COST EFFECTIVENESS SUMMARY FOR
NO CONTROL TECHNIQUES APPLIED TO
DUAL-FUEL ENGINES 2-46
TABLE 3-1. OIL AND GAS INDUSTRY APPLICATIONS OF
STATIONARY 1C ENGINES CIRCA 1979 .... 3-14
TABLE 3-2. GENERAL INDUSTRIAL AND MUNICIPAL APPLICATIONS
OF STATIONARY 1C ENGINES CIRCA 1979 . . 3-16
TABLE 3-3. AGRICULTURAL APPLICATIONS OF STATIONARY
1C ENGINES CIRCA 1979 3-17
TABLE 3-4. ELECTRICAL POWER GENERATION BY STATIONARY
1C ENGINES CIRCA 1979 3-19
TABLE 4-1. AVERAGE NOY EMISSIONS FOR 1C ENGINES .... 4-12
Jv
TABLE 5-1. RANGE OF EMISSIONS RESULTING FROM A/F
ADJUSTMENT FOR ONE MANUFACTURER'S
RICH-BURN, MEDIUM-SPEED ENGINES .... 5-6
TABLE 5-2. ACHIEVABLE CONTROLLED EMISSION LEVELS USING
A/F ADJUSTMENT 5-7
TABLE 5-3. CONTROLLED EMISSION LEVELS FOR PSC
INSTALLATIONS IN THE SOUTH COAST AIR
QUALITY MANAGEMENT DISTRICT 5-19
TABLE 5-4. CONTROLLED EMISSION LEVELS AND CORRESPONDING
ENGINE POWER DERATE FOR PSC®
INSTALLATIONS 5-22
TABLE 5-5. EMISSION SUMMARY OF RICH-BURN ENGINES
FOLLOWING RETROFIT TO LOW-EMISSION
COMBUSTION USING A PRECOMBUSTION CHAMBER 5-38
TABLE 5-6. ACHIEVABLE CONTROLLED EMISSION LEVELS FOR NEW
LOW-EMISSION ENGINES DEVELOPED FROM
RICH-BURN ENGINE DESIGNS 5-40
Xlll
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LIST OF TABLES (continued)
Page
TABLE 5-7. ACHIEVABLE NOX EMISSION REDUCTIONS FOR
LEAN-BURN ENGINES USING A COMBINATION OF
A/F ADJUSTMENT AND IGNITION TIMING
RETARD 5-54
TABLE 5-8. GAS-FUELED SCR APPLICATIONS AND OPERATING
EXPERIENCE FOR ONE CATALYST VENDOR ... 5-62
TABLE 5-9. ACHIEVABLE EMISSION LEVELS FOR NEW AND
RETROFIT LOW-EMISSION ENGINES DEVELOPED
FROM LEAN-BURN DESIGNS 5-68
TABLE 5-10. EFFECT OF FUEL INJECTION TIMING RETARD ON
EMISSIONS AND FUEL CONSUMPTION FOR
DIESEL ENGINES 5-72
TABLE 5-11. DIESEL-FUELED SCR APPLICATIONS FOR ONE
CATALYST VENDOR 5-75
TABLE 5-12. RESULTS OF RETARDING THE INJECTION TIMING FOR
ONE DUAL-FUEL ENGINE MODEL 5-77
TABLE 5-13. EMISSIONS COMPLIANCE TEST RESULTS FOR A
DUAL-FUEL ENGINE USING SCR 5-79
TABLE 5-14. NOMINAL EMISSION LEVELS COMPARING
OPEN-CHAMBER AND PRECOMBUSTION CHAMBER
DESIGNS FOR DUAL FUEL ENGINES 5-82
TABLE 5-15. EMISSION TEST RESULTS FOR A LOW-EMISSION
DUAL-FUEL ENGINE RETROFIT WITH A
PRECOMBUSTION CHAMBER 5-83
TABLE 6-1. TOTAL CAPITAL COST COMPONENTS AND FACTORS . . 6-3
TABLE 6-2. TOTAL ANNUAL COST ELEMENTS AND FACTORS ... 6-5
TABLE 6-3. UNCONTROLLED NOX EMISSION FACTORS FOR COST
EFFECTIVENESS CALCULATIONS 6-7
TABLE 7-1. RICH-BURN SI ENGINES 7-3
TABLE 7-2. LEAN-BURN SI ENGINES 7-5
TABLE 7-3. NO.. EMISSION REDUCTIONS FOR DIESEL CI ENGINES 7-6
J\.
TABLE 7-4. DUAL-FUEL CI ENGINES 7-8
xiv
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LIST OF TABLES (continued)
Page
TABLE 7-5. EFFECTS OF NO CONTROL TECHNIQUES ON CO AND
HC EMISSIONS 7-9
TABLE 7-6. EFFECTS OF NOy CONTROL TECHNIQUES ON FUEL
CONSUMPTION AND POWER OUTPUT 7-12
xv
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1.0 INTRODUCTION
Congress, in the Clean Air Act Amendments of 1990 (CAAA),
amended Title I of the Clean Air Act (CAA) to address ozone
nonattainment areas. A new Subpart 2 was added to Part D of
Section 103. Section 183(c) of the new Subpart 2 provides that:
[w]ithin 3 years after the date of the enactment of the
CAAA, the Administrator shall issue technical documents
which identify alternative controls for all categories of
stationary sources of...oxides of nitrogen which emit or
have the potential to emit 25 tons per year or more of such
air pollutant.
These documents are to be subsequently revised and updated as
determined by the Administrator.
Stationary reciprocating engines have been identified as a
category that emits more than 25 tons of nitrogen oxide (NOX) per
year. This alternative control techniques (ACT) document
provides technical information for use by State and local
agencies to develop and implement regulatory programs to control
NOX emissions from stationary reciprocating engines. Additional
ACT documents are being developed for other stationary source
categories.
Reciprocating engines are used in a broad scope of
applications. It must be recognized that the alternative control
techniques and the corresponding achievable NOX emission levels
presented in this document may not be applicable for every
reciprocating engine application. The size and design of the
engine, the operating duty cycle, site conditions, and other
site-specific factors must be taken into consideration, and the
suitability of an alternative control technique must be
determined on a case-by-case basis.
1-1
-------
The information in this ACT document was generated through a
literature search and from information provided by engine
manufacturers, control equipment vendors, engine users, and
regulatory agencies. Chapter 2.0 presents a summary of the
findings of this study. Chapter 3.0 presents information on
engine operation and industry applications. Chapter 4.0 contains
a discussion of NOX formation and uncontrolled NOX emission
factors. Alternative control techniques and achievable
controlled emission levels are included in Chapter 5.0. The cost
and cost effectiveness of each control technique are presented in
Chapter 6.0. Chapter 7.0 describes environmental and energy
impacts associated with implementing the NOX control techniques.
1-2
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2.0 SUMMARY
This chapter presents a summary of uncontrolled nitrogen
oxide (NOX) emissions factors, NOX emission control techniques,
achievable controlled NOX emission levels, and the costs and cost
effectiveness for NOX control techniques applied to stationary
reciprocating internal combustion (1C) engines. The extent of
applicability and the effects of NOX control techniques on engine
operating parameters and carbon monoxide (CO) and hydrocarbon
(HC) emissions are also summarized for each control technique.
In this document, emissions are stated in units of grams per
horsepower-hour (g/hp-hr), parts per million by volume (ppmv),
and pounds per million British thermal units (Ib/MMBtu). All
emission levels stated in units of ppmv are corrected to
15 percent oxygen (02), unless stated otherwise. Emission rates
were requested from engine manufacturers in units of g/hp-hr.
Published reports and test data often report emission levels in
either g/hp-hr or ppmv. Conversion factors presented in
Chapter 4 are used throughout this document to convert g/hp-hr to
ppmv and vice-versa. Where HC emission levels are not speciated,
it is expected that the emission levels presented correspond to
nonmethane hydrocarbon (NMHC) levels rather than total
hydrocarbon (THC) levels.
Information for both spark-ignition (SI) and compression-
ignition (CD engines are presented for operation on gaseous and
oil fuels. Gasoline-fueled engines are not included in this
document due to limited stationary applications and available
information for these engines.
2-1
-------
This document presents information by engine type
(i.e., rich-burn SI, lean-burn SI, and diesel and dual-fuel
engines). A rich-burn engine is classified as one with an
air-to-fuel ratio (A/F) operating range that is near
stoichiometric or fuel-rich of stoichiometric and can be adjusted
to operate with an exhaust oxygen concentration of 1 percent or
less. A lean-burn engine is classified as one with an A/F
operating range that is fuel-lean of stoichiometric and cannot be
adjusted to operate with an exhaust concentration of less than 1
percent. All naturally aspirated, four-cycle SI engines and some
turbocharged, four-cycle SI engines are rich-burn engines. All
other engines, including all two-cycle SI engines and all CI
engines, are lean-burn engines.
Some control techniques discussed in this document require
that additional equipment be installed on the engine or in the
engine exhaust. Issues regarding the point of responsibility for
potential engine mechanical malfunctions or safety concerns
resulting from the use of the control techniques presented are
not evaluated in this document.
Section 2.1 presents a summary of uncontrolled NOX
emissions. Section 2.2 presents a summary of the performance and
achievable controlled NO., emissions of each control technique. A
J^
summary of the total capital and annual costs and cost
effectiveness of each control technique is presented in
Section 2.3.
2.1 UNCONTROLLED NOX EMISSIONS
The operating temperatures and pressures in 1C engines
produce NOX emissions. Thermal NOX is the predominant mechanism
by which NOX is formed in 1C engines because most engines burn
fuels that contain little or no nitrogen and, therefore, fuel NOX
formation is minimal.
Fuel rates and uncontrolled NOX emission levels for SI and
CI engines were provided by engine manufacturers. These fuel and
emission rates were averaged for a range of engines sizes and are
presented in Table 2-1. For rich-burn SI engines, average
uncontrolled NO., emission factors range from 13.1 to 16.4 g/hp-hr
Jt
2-2
-------
TABLE 2-1.
AVERAGE HEAT RATES AND UNCONTROLLED NO EMISSION
FACTORS FOR RECIPROCATING ENGINES
Engine
size, hp
RICH-BURN
0-200
201-400
401-1000
1001-2000
2001-4000
4001 +
No of
engines
Average
heat
rate,
Btu/hp-hr*
Average
NOX
emissions,
g/hp-hr*
Average NOX
emissions,
ppmv
©15% O2b
Average
NOX
emission
factor,
lb/MMBtuc
Weighted average for each engine type
NOX,
g/hp-hr
NOX,
ppmv
©15% 02b
NOX,
Ib/MMBtu
SI ENGINES
8
13
31
19
10
2
8140
7820
7540
7460
6780
6680
13.1
16.4
16.3
16.3
15.0
14.0
880
1100
1090
1090
1000
940
3.54
4.62
4.76
4.81
4.87
4.62
15.8
1060
4.64
LEAN-BURN SI ENGINES
0-400
401-1000
1001-2000
2001-4000
4001 +
7
17
43
30
25
8760
7660
7490
7020
6660
7.9
18.6
17.8
17.2
16.5
580
1360
1300
1260
1200
1.99
5.35
5.23
5.40
5.46
16.8
1230
5.13
DIESEL ENGINES
0-200
201-400
401-1000
1001-2000
2001-4000
4001 +
12
8
22
14
6
6
6740
6600
6790
6740
6710
6200
11.2
11.8
13.0
11.4
11.4
12.0
820
860
950
830
830
880
3.66
3.94
4.22
3.73
3.74
4.26
12.0
880
3.95
DUAL-FUEL ENGINES
700-1200
1201-2000
2001-4000
4001 +
5
3
5
4
6920
7220
6810
6150
10.0
10.7
8.4
4.9
730
780
610
360
3.18
3.26
2.72
1.75
8.5
620
2.72
"Calculated from figures corresponding to International Standards Organization 0SO) conditions, as provided by engine
manufacturers.
"Calculated from g/hp-hr figures using the conversion factors from Chapter 4.
clb/MMBtu = (g/hp-hr) x (lb/454g) x (I/Heat Rate) x (1,000,000).
"Weighted average is calculated by multiplying the average NOX emission factor by the number of engines for each engine
size and dividing by the total number of engines. For example, for dual-fuel engines, the weighted average is calculated
[(5 x 10.0) + (3 x 10.7) + (5 x 8.4) + (4 x 4.9)]/17 = 8.5 g/hp-hr
2-3
-------
(880 to 1,100 ppmv), or 3.54 to 4.87 Ib/MMBtu. Lean-burn SI
engine average NOX emission levels range from 7.9 to 18.6 g/hp-hr
(580 to 1,360 ppmv), or 1.99 to 5.46 Ib/MMBtu. Average NO,.
Jv
emission levels from diesel engines range from 11.2 to 13.0 g/hp-
hr (820 to 950 ppmv), or 3.66 to 4.26 Ib/MMBtu. Duel-fuel engine
average NOX emission levels range from 4.9 to 10.7 g/hp-hr
(360 to 780 ppmv), or 1.75 to 3.26 Ib/MMBtu.
Weighted averages were also calculated for NOX emission
levels from each engine type. These weighted averages show that
SI engines have the highest NOX emission rates, at 16.8 and
15.8 g/hp-hr (1,060 and 1,230 ppmv), or 5.13 and 4.64 Ib/MMBtu
for lean-burn and rich-burn engines, respectively. The weighted
average for diesel engines is 12.0 g/hp-hr (880 ppmv), or
3.95 Ib/MMBtu. Dual-fuel engines have the lowest weighted NO..
Jv
emission rate, at 8.5 g/hp-hr (620 ppmv), or 2.72 Ib/MMBtu.
2.2 CONTROL TECHNIQUES AND ACHIEVABLE NOX EMISSION REDUCTIONS
The control techniques included in this document for each
engine type are listed below:
Rich-burn SI engines Lean-burn SI engines
A/F adjustment (AF) A/F adjustment
Ignition timing retard (IR) Ignition timing retard
A/F adjustment plus ignition A/F adjustment plus ignition
timing retard timing retard
Prestratified charge (PSC®) Selective catalytic reduction
Nonselective catalytic (SCR)
reduction (NSCR) Low-emission combustion
Low-emission combustion (L-E)
Diesel engines Dual-fuel engines
Injection timing retard (IR) Injection timing retard
Selective catalytic reduction Selective catalytic reduction
Low-emission combustion
The performance of each control technique is summarized in
this section, including applicability and the extent of
application, achievable controlled NOX emission levels, and the
effect on engine performance and CO and HC emissions. Controls
that apply to rich-burn SI engines are discussed in
2-4
-------
Section 2.2.1; lean-burn SI engines in Section 2.2.2; and diesel
and dual-fuel engines in Section 2.2.3. These control techniques
are discussed in greater detail in Chapter 5.
2.2.1 Control Techniques for Rich-Burn SI Engines
A summary of the achievable NOX emission reductions for
rich-burn SI engines is presented in Tables 2-2 and 2-3. The
effects of these control techniques on other emissions, fuel
consumption, and power output are presented in Table 2-4.
2.2.1.1 AF. Adjusting the A/F toward fuel-rich operation
reduces the oxygen available to combine with nitrogen, thereby
inhibiting NOX formation. The low-oxygen environment also
contributes to incomplete combustion, which results in lower
combustion temperatures and, therefore, lower NOX formation
rates. The incomplete combustion also increases CO emissions
and, to a lesser extent, HC emissions. Combustion efficiency is
also reduced, which increases brake-specific fuel consumption
(BSFC). Excessively rich A/F's may result in combustion
instability and unacceptable increases in CO emissions.
The A/F can be adjusted on all new or existing rich-burn
engines. Sustained NOX reduction with changes in ambient
conditions and engine load, however, is best accomplished with an
automatic A/F control system.
The achievable NOX emission reduction ranges from
approximately 10 to 40 percent from uncontrolled levels. Based
on an average uncontrolled NOX emission level of 15.8 g/hp-hr
(1,060 ppmv) , the expected range of controlled NO,, emissions is
Jv
from 9.5 to 14.0 g/hp-hr (640 to 940 ppmv). Available data show
that the achievable NOX reduction using AF varies for each engine
model and even among engines of the same model, which suggests
that engine design and manufacturing tolerances influence the
effect of AF on NOX emission reductions.
2.2.1.2 JR. Ignition timing retard delays initiation of
combustion to later in the power cycle, which increases the
volume of the combustion chamber and reduces the residence time
of the combustion products. This increased volume and reduced
residence time offers the potential for reduced NOV formation.
Jv
2-5
-------
TABLE 2-2. EXPECTED RANGE OF NOX EMISSION REDUCTIONS AND
CONTROLLED EMISSION LEVELS FOR CONTROL TECHNIQUES APPLIED TO
RICH-BURN SI ENGINES (NATURAL GAS FUEL)
Control
technique
AF
IR
AF + IR
PSC
NSCR
L-E
Average uncontrolled NOX emission
level*
g/hp-hr
15.8
15.8
15.8
15.8
15.8
15.8
ppmv
1,060
1,060
1,060
1,060
1,060
1,060
Achievable NOX
reduction, %
10-40
0-40
10-40
87
90-98C
87
Expected controlled NOX emission
levels
g/hp-hr
9.5 - 14.0
9.5 - 15.8
9.5 - 14.0
2.0b
0.3 - 1.6
2.0b
ppmv
640-940
640- 1,060
640-940
135
20- 110
135
*The uncontrolled emission rate shown is a representative average for rich-bum SI engines. The actual
uncontrolled emission rate will vary from engine to engine.
^Guaranteed controlled NOX emission level offered by control equipment supplier.
Guaranteed NOX reduction efficiency offered by catalyst vendors.
2-6
-------
TABLE 2-3.
POTENTIAL NO REDUCTIONS FOR RICH-BURN SI ENGINES
(NATURAL GAS FUEL)
RICH-BURN ENGINES
Engine
size,
hp
100
500
1,000
1,500
2,000
3,000
4,000
6,000
8,000
Average
uncontrolled
NOX emission
level, g/hp-hr8
15.8
Average
uncontrolled
NOX emission
level, tons/yr
13.9
69.6
139
209
278
418
557
835
1,110
Potential NOx reduction, tons/yr5
Parametric
adjustments0
1.39-5.57
6.96 - 27.8
13.9 - 55.7
20.9 - 83.5
27.8- 111
41.8 - 167
55.7 - 223
83.5 - 334
111 -445
PSCd
12.2
60.8
122
182
243
365
486
730
973
NSCRe
12.5
62.6
125
188
251
376
501
752
1,000
Low-emission
combustion
12.2
60.8
122
182
243
365
486
730
973
aThe uncontrolled emission rate shown is a representative average for rich-burn SI engines. The actual
uncontrolled emission rate will vary from engine to engine.
"Potential NOX reductions correspond to 8,000 annual operating hours. NOX reductions for other utilization
rates can be estimated by multiplying the value in the table by the actual annual operating hours and dividing
by 8,000.
CNOX reductions for parametric adjustments (AF, IR, and AF + IR) correspond to a reduction efficiency range
of 10 to 40 percent from uncontrolled levels.
NOX reductions for PSC and low-emission combustion correspond to a controlled emission level of 2 g/hp-hr.
eNOx reductions for NSCR correspond to a reduction efficiency of 90 percent.
2-7
-------
TABLE 2-4. EFFECTS OF NO CONTROL TECHNIQUES
RICH-BURN SI ENGINES
ON
RICH-BURN ENGINES
Control technique
AF
IR
AFandIR
PSC
NSCR
L-E
Effect on CO
emissions
increase
(1 to 33 g/hp-hr)
minimal
increase0
increase
(£3.0 g/hp-hr)
increase
(£37 g/hp-hr)f
increase
(£3.5 g/hp-hr)
Effect on HC
emissions
increase
(0.2 to 0.3 g/hp-hr)
minimal
increase6
increase
(£2.0 g/hp-hr)
minimal^
(£3.3 g/hp-hr)
increase
(£2.0 g/hp-hr)
Effect on
fuel consumption
0 to 5 percent
increase
0 to 7 percent
increase
0 to 7 percent
increase
2 percent increase
0 to 5 percent
increase
variable^
Effect on power
output8
none"
none*5
minimal"
5 to 20 percent
reduction
1 to 2 percent
reduction
none
*At rated load.
"Severe adjustment or retard may reduce power output.
°The increase is expected to be less than that shown for A/F adjustment.
One source reported a 5 percent power reduction at rated load.
eAccording to a VCAPCD test report summary.
*From VCAPCD data base, consistent with 4,500 ppmv CO emission limit.
Sin most engines the effect is a decrease in fuel consumption of 0-5 percent.
2-8
-------
The extent to which the ignition timing can be retarded to reduce
NOX emissions varies for each engine, as IR increases exhaust
temperatures, which may adversely impact exhaust valve life and
turbocharger performance, and extreme levels of IR may result in
combustion instability and a loss of power. Brake-specific fuel
consumption increases. Limited data suggest that moderate levels
of IR has little effect on CO and HC emission levels.
Ignition timing can be adjusted on all new or existing
rich-burn engines. Sustained NOX reduction with changes in
ambient conditions and engine load, however, is best accomplished
using an electronic ignition control system.
The achievable NOX emission reduction ranges from virtually
no reduction to as high as 40 percent. Based on an average
uncontrolled NOX emission level of 15.8 g/hp-hr (1,060 ppmv), the
expected range of controlled NO., emissions is from 9.5 to 15.8
Jv
g/hp-hr (640 to 1,060 ppmv). Available data and information
provided by engine manufacturers show that, like AF, the
achievable NOX reductions using IR are engine-specific.
2.2.1.3 AF and IR. The combination of AF and IR can be
used to reduce NOX emissions. Available data and information
from engine manufacturers suggest that the achievable NOX
emission reduction for the combination of control techniques is
approximately the same as for AF alone (i.e., 10 to 40 percent)
but offers some flexibility in achieving these reductions. Since
parametric adjustments affect such operating characteristics as
fuel consumption, response to load changes, and other emissions
(especially CO), the combination of AF and IR offers the
potential to reduce NOX emissions while minimizing the impact on
other operating parameters.
2.2.1.4 PSC®. This add-on control technique facilitates
combustion of a leaner A/F. The increased air content acts as a
heat sink, reducing combustion temperatures, thereby reducing NO-.
Jv
formation rates. Because this control technique is installed
upstream of the combustion process, PSC® is often used with
engines fueled by sulfur-bearing gases or other gases (e.g.,
2-9
-------
sewage or landfill gases) that may adversely affect some catalyst
materials.
Prestratified charge applies only to four-cycle, carbureted
engines. Pre-engineered, "off-the-shelf kits are available for
most new or existing candidate engines, regardless of age or
size. According to the vendor, PSC® to date has been installed
on engines ranging in size up to approximately 2,000 hp.
The vendor offers guaranteed controlled NOX emission levels
of 2 g/hp-hr (140 ppmv), and available test data show numerous
controlled levels of 1 to 2 g/hp-hr (70 to 140 ppmv). The extent
to which NOX emissions can be reduced is determined by the extent
to which the air content of the stratified charge can be
increased without excessively compromising other operating
parameters such as power output and CO and HC emissions. The
leaner A/F effectively displaces a portion of the fuel with air,
which may reduce power output from the engine. For naturally
aspirated engines, the power reduction can be as high as 20
percent, according to the vendor. This power reduction can be at
least partially offset by modifying an existing turbocharger or
installing a turbocharger on naturally aspirated engines. In
general, CO and HC emission levels increase with PSC®, but the
degree of the increase is engine-specific. The effect on BSFC is
a decrease for moderate controlled NOX emission levels (4 to
7 g/hp-hr, or 290 to 500 ppmv), but an increase for controlled
NOX emission levels of 2 g/hp-hr (140 ppmv) or less.
2.2.1.5 NSCR. Nonselective catalytic reduction is
essentially the same catalytic reduction technique used in
automobile applications and is also referred to as a three-way
catalyst system because the catalyst reactor simultaneously
reduces NOX, CO, and HC to water (H20), carbon dioxide (C02), and
diatomic nitrogen (N2). The chemical stoichiometry requires that
02 concentration levels be kept at or below approximately
0.5 percent, and most NSCR systems require that the engine be
operated at fuel-rich A/F's. As a result, CO and HC emissions
typically increase, and BSFC also increases due to the fuel-rich
2-10
-------
operation and the increased backpressure on the engine from the
catalyst reactor.
Nonselective catalytic reduction applies only to carbureted
rich-burn engines and can be retrofit to existing installations.
Sustained NOX reductions are achieved with changes in ambient
conditions and operating loads only with an automatic A/F control
system, and a suitable A/F controller is not available for fuel-
injected engines. In addition, there is limited experience with
fuels other than natural gas (e.g., sewage gas, landfill gas, and
gases containing hydrogen sulfide [H2S]), as these fuels contain
constituents that may mask or poison the catalyst.
Catalyst vendors quote NOX emission reduction efficiencies
of 90 to 98 percent. Based on an average uncontrolled NOX
emission level of 15.8 g/hp-hr (1,060 ppmv), the expected range
of controlled NOX emissions is from 0.3 to 1.6 g/hp-hr (20 to 110
ppmv). Numerous test reports support this NOX reduction
efficiency range, but the corresponding CO emission levels range
up to 37 g/hp-hr (4,500 ppmv) in some cases. Where controlled
NOX emission levels result in unacceptable CO emission rates, an
oxidation catalyst may be required to reduce these emissions.
The predominant catalyst material used in NSCR applications
is a platinum-based metal catalyst. The spent catalyst material
is not considered hazardous, and most catalyst vendors accept
return of the material, often with a salvage value that can be
credited toward purchase of replacement catalyst.
2.2.1.6 L-E. Engine manufacturers have developed low-
emission combustion designs (often referred to as torch ignition,
or jet cell combustion) that operate at much leaner A/F's than do
conventional designs. These designs incorporate improved swirl
patterns to promote thorough air/fuel mixing and may include a
precombustion chamber (PCC). A PCC is an antechamber that
ignites a relatively fuel-rich mixture that propagates to the
main combustion chamber. The high exit velocity from the PCC
promotes mixing and complete combustion of the lean A/F in the
main chamber, effectively lowering combustion temperatures and,
therefore, NOX emission levels.
2-11
-------
Low-emission combustion designs are available from engine
manufacturers for most new SI engines, and retrofit kits are
available for some existing engine models. For existing engines,
the modifications required for retrofit are similar to a major
engine overhaul, and include a turbocharger addition or upgrade
and new intake manifolds, cylinder heads, pistons, and ignition
system. The intake air and exhaust systems must also be modified
or replaced due to the increased air flow requirements.
Controlled NOX emission levels reported by manufacturers for
L-E are generally in the 2 g/hp-hr (140 ppmv) range, although
lower levels may be quoted on a case-by-case basis. Emission
test reports show controlled emission levels ranging from 1.0 to
2.0 g/hp-hr (70 to 140 ppmv). Information provided by
manufacturers shows that, in general, BSFC decreases slightly for
L-E compared to rich-burn designs, although in some engines the
BSFC increases. An engine's response to increases in load is
adversely affected by L-E, which may make this control technique
unsuitable for some installations, such as stand-alone power
generation applications. The effect on CO and Hf emissions is a
slight increase in most engine designs.
2.2.2 Control Techniques for Lean-Burn SI Engines
The control techniques available for lean-burn SI engines
are discussed in this section. A summary of the achievable NOX
emission reductions for lean-burn SI engines using these control
techniques is presented in Tables 2-5 and 2-6. The effects of
these control techniques on other emissions, fuel consumption,
and power output are presented in Table 2-7.
2.2.2.1 AF. Adjusting the A/F toward fuel-lean operation
increases the volume of air in the combustion process, which
increases the heat capacity of the mixture, lowering combustion
temperatures and reducing NOX formation. Limited data suggest CO
emissions increase slightly, and HC emissions also increase.
Combustion efficiency is reduced, and BSFC increases.
2-12
-------
TABLE 2-5. EXPECTED RANGE OF NO EMISSION REDUCTIONS AND
CONTROLLED EMISSION LEVELS FOR CONTROL TECHNIQUES APPLIED TO
LEAN-BURN SI ENGINES (NATURAL GAS FUEL)
Control
technique
AF
IR
AF -1- IR
SCR
L-E
Average uncontrolled NOX emission
level"
g/hp-hr
16.8
16.8
16.8
16.8
16.8
ppmv
1,230
1,230
1,230
1,230
1,230
Achievable NOX
reduction, %
5-30
0-20
20-40
90b
87
Expected controlled NOX emission
levels
g/hp-hr
11.8- 16.0
13.4- 16.8
10.1 - 13.4
1.7
2.0C
ppmv
860- 1,170
980- 1,260
740 - 980
125
150
aThe uncontrolled emission rate shown is a representative average for lean-burn SI engines. The actual uncontrolled
emission rate will vary from engine to engine.
^Guaranteed NOX reduction available from most catalyst vendors.
°Guaranteed controlled NOX emission level available from engine manufacturers.
2-13
-------
TABLE 2-6. POTENTIAL NO REDUCTIONS
FOR LEAN-BURN SI ENGINES
LEAN-BURN ENGINES
Engine
size,
hp
100
500
1,000
1,500
2,000
3,000
4,000
6,000
8,000
10,000
Avenge
uncontrolled
NOX emission
level, g/hp-hr*
16.8
Average
uncontrolled
NOX emission
level, tons/yr
14.8
74.0
148
222
296
444
592
888
1,184
1,480
Potential NOx reduction, tons/yr*'
Parametric
adjustments0
0.74-5.18
3.70 - 25.9
7.40-51.8
11.1-77.7
14.8 - 104
22.2 - 155
29.6 - 207
44.4-311
59.2 - 414
74.0 - 518
SCRd
13.3
66.6
133
200
266
400
533
799
1,070
1,330
Low-emission
combustion6
13.0
65.2
130
196
261
391
522
782
1,040
1,300
aThe uncontrolled emission rate shown is a representative average for lean-bum SI engines. The actual
uncontrolled emission rate will vary from engine to engine.
''Potential NO» reductions correspond to 8,000 annual operating hours. NOX reductions for other utilization
rates can be estimated by multiplying the value in the table by the actual annual operating hours and dividing
by 8,000.
°NOX reductions for parametric adjustments correspond to a reduction efficiency range of 5 to 35 percent from
uncontrolled levels.
NOX reductions for SCR correspond to a reduction efficiency of 90 percent.
CNOX reductions for low-emission combustion correspond to a controlled emission level of 2 g/hp-hr.
2-14
-------
TABLE 2-7.
EFFECTS OF NOX CONTROL TECHNIQUES ON
LEAN-BURN SI ENGINES
LEAN-BURN ENGINES
Control technique
AF
IR
AFandIR
SCR
L-E
Effect on CO
emissions
minimal
minimal
minimal0
minimal
increase
(£3.5 g/hp-hr)
Effect on HC
emissions
slight increase
minimal
minimal0
minimal
increase
(«£ 2.0 g/hp-hr)
Fuel consumption
0 to 5 percent
increase
0 to 5 percent
increase
0 to 5 percent
increase
0.5 percent
increase
variable6
Effect on power
output8
none"
noneb
minimal"
1 to 2 percent
reduction
none
aAt rated load.
"Severe adjustment or retard may reduce power output.
cThe increase is expected to be less than that shown for A/F adjustment.
One source reported a 5 percent power reduction at rated load.
^Ln most engines the effect is a decrease in fuel consumption of 0 to 5 percent.
2-15
-------
Excessively lean A/F's may result in combustion instability and
lean misfire.
The A/F can be adjusted in the field on most lean-burn
engines. Pump- and blower-scavenged engines, however, have no
provisions for AF. To supply the increased volume of air needed
for AF, a turbocharger may be required for existing naturally
aspirated engines, and modification or replacement of the
turbocharger may be required for turbocharged engines. An
automatic control system to regulate the delivered volume of air
is also required for sustained NOX reduction with changes in
ambient conditions and engine loads.
The achievable NOX emission reduction for AF ranges from
approximately 5 to 30 percent. Based on an average uncontrolled
NOX emission level of 16.8 g/hp-hr (1,230 ppmv), the expected
range of controlled NOX emissions is from 11.8 to 16.0 g/hp-hr
(860 to 1,170 ppmv). Available data show that the achievable NOX
reduction using AF varies for each engine model and even among
engines of the same model, which suggests that engine design and
nanufacturing tolerances influence the effect of AF on NOX
emission reduction.
2.2.2.2 IR. Ignition timing retard in lean-burn SI engines
has similar effects on NOY formation and engine performance to
Jx.
those discussed for rich-burn engines in Section 2.2.1.2.
Limited data for IR in lean-burn engines show no definite trend
for CO emissions for moderate levels of IR and only a slight
increase in HC emissions.
Like rich-burn engines, IR can be performed on all new or
existing lean-burn engines. Sustained NOX reductions, however,
require an electronic ignition control system to automatically
adjust the timing for changes in ambient conditions and engine
load.
The achievable NOX emission reduction using IR ranges from
virtually no reduction to as high as 20 percent. Based on an
average uncontrolled NO., emission level of 16.8 g/hp-hr (1,230
Jv
ppmv), the expected range of controlled NOX emissions is from
13.4 to 16.8 g/hp-hr (980 to 1,260 ppmv). Available data and
2-16
-------
information provided by engine manufacturers show that the
achievable NOX reductions using IR are engine-specific.
2.2.2.3 AF and IR. The combination of AF and IR can be
used to reduce NOX emissions. Limited data and information
available on the combination of control techniques suggest that,
as is the case for each control technique used independently, the
achievable NOX emission reduction is engine-specific. Based on
available data and information from engine manufacturers, it is
estimated that the achievable NOX emission reduction for the
combination of control techniques is 20 to 40 percent. Based on
an average uncontrolled NOX emission level of 16.8 g/hp-hr (1,230
ppmv), the expected range of controlled NOX emissions is from
10.1 to 13.4 g/hp-hr (740 to 980 ppmv).
The effect of each control technique used independently is a
slight increase in CO and HC emissions, and it is expected that
the combination of controls would produce similar results. Since
parametric adjustments affect such operating characteristics as
fuel consumption, response to load changes, and other emissions,
the combination of AF and IR offers the potential to reduce NOX
emissions while minimizing the impact on these operating
parameters.
2.2.2.4 SCR. Selective catalytic reduction is an add-on
control technique that injects ammonia (NH3) into the exhaust,
which reacts with NOX to form N2 and H20 in the catalyst reactor.
The two primary catalyst formulations are base-metal (usually
vanadium pentoxide) and zeolite. Spent catalysts containing
vanadium pentoxide may be considered a hazardous material in some
areas, requiring special disposal considerations. Zeolite
catalyst formulations do not contain hazardous materials.
Selective catalytic reduction applies to all lean-burn SI
engines and can be retrofit to existing installations except
where physical space constraints may exist. There is limited
operating experience to date, however, with these engines. A
total of 23 SCR installations with lean-burn SI engines were
identified in the United States from information provided by
catalyst vendors, in addition to over 40 overseas installations.
2-17
-------
To date there is also little experience with SCR in variable load
applications due to ammonia injection control limitations.
Several vendors cite the availability of injection systems,
however, designed to operate in variable load applications.
Injection systems are available for either anhydrous or aqueous
ammonia. As is the case for NSCR catalysts, fuels other than
pipeline-quality natural gas may contain contaminants that mask
or poison the catalyst, which can render the catalyst ineffective
in reducing NOX emissions. Catalyst vendors typically guarantee
a 90 percent NOX reduction efficiency for natural gas-fired
applications, with an ammonia slip level of 10 ppmv or less. One
vendor offers a NOX reduction guarantee of 95 percent for gas-
fired installations. Based on an average uncontrolled NOX
emission level of 16.8 g/hp-hr (1,230 ppmv), the expected
controlled NOX emission level is 1.7 g/hp-hr (125 ppmv).
Emission test data show NOX reduction efficiencies of
approximately 65 to 95 percent for existing installations.
Ammonia slip levels were available only for a limited number of
installations ior manually adjusted ammonia injection control
systems and ranged from 20 to 30 ppmv. Carbon monoxide and HC
emission levels are not affected by implementing SCR. The engine
BSFC increases slightly due to the backpressure on the engine
caused by the catalyst reactor.
2.2.2.5 L-E. Low-emission combustion designs are available
from engine manufacturers for most new lean-burn SI engines. The
required engine modifications, effect on engine performance,
achievable controlled NOX emission levels, and effect on CO and
HC emissions are essentially the same as for rich-burn engines
and are discussed in Section 2.2.1.6.
2.2.3 Control Techniques for Diesel and Dual-Fuel CI Engines
The control techniques available for CI engines are
discussed in this section. A summary of the achievable NOX
emission reductions for diesel and dual-fuel engines using these
control techniques is presented in Tables 2-8, 2-9, and 2-10. The
effect of these control techniques on other emissions, fuel
2-18
-------
TABLE 2-8. EXPECTED RANGE OF NO EMISSION REDUCTIONS AND
CONTROLLED EMISSION LEVELS F§R CONTROL TECHNIQUES
APPLIED TO DIESEL AND DUAL-FUEL ENGINES
DIESEL ENGINES
Control
technique
IR
SCR
Average uncontrolled NOX emission
level'
g/hp-hr
12.0
12.0
ppmv
875
875
Achievable NOX
reduction, %
20-30
80 - 90b
Expected controlled NOX emission
levels
g/hp-hr
8.4 - 9.6
1.2-2.4
ppmv
610 - 700
90 - 175
DUAL-FUEL ENGINES
IR
SCR
L-E
8.5
8.5
8.5
620
620
620
20-30
80 - 90b
75
6.0 - 6.8
0.8- 1.7
2.0C
430 - 500
600 - 125
150
*The uncontrolled emission rates shown are representative averages for diesel and dual-fuel engines. The actual
uncontrolled emission rate varies from engine to engine.
"Guaranteed NOX reduction available from most catalyst vendors.
cGuaranteed controlled NO, emission level available from engine manufacturers.
2-19
-------
TABLE 2-9. POTENTIAL NOY REDUCTIONS FOR DIESEL ENGINES
DIESEL ENGINES
Engine
size, hp
100
500
1,000
1,500
2,000
3,000
4,000
6,000
8,000
Average
uncontrolled NOX
emission level,
g/hp-hr8
12.0
Average
uncontrolled NOX
emission level,
tons/yr
10.6
52.9
106
159
211
317
423
634
846
Potential NOX reduction, tons/yr
Injection retard0
2.11 -3.17
10.6 - 15.9
21.1 -31.7
31.7-47.6
42.3 - 63.4
63.4 - 95.2
84.6 - 127
127 - 190
169 - 254
SCRd
9.5
47.6
95
143
190
285
381
571
761
&The uncontrolled emission rate shown is a representative average for diesel engines. The actual uncontrolled
emission rate will vary from engine to engine.
"Potential NOX reductions correspond to 8,000 annual operating hours. NOX reductions for other utilization
rate? -an be estimated by multiplying the value in the table by the actual annual operating hours and dividing
by 8,000.
CNOX reductions for injection retard correspond to a reduction efficiency range of 20 to 30 percent from
uncontrolled levels.
reductions for SCR correspond to a reduction efficiency of 90 percent.
2-20
-------
TABLE 2-10. POTENTIAL NOX REDUCTIONS
FOR DUAL-FUEL ENGINES
DUAL-FUEL ENGINES
Engine size,
hp
700
1,000
1,500
2,000
3,000
4,000
6,000
8,000
Average
uncontrolled NOX
emission level,
g/hp-hr*
8.5
Average
uncontrolled
NOX emission
level, tons/yr
52.4
74.9
112
150
225
300
449
599
Potential NOX reduction, tons/yr^
Injection
retard0
10.5 - 15.7
15.0 - 22.5
22.5 - 33.7
30.0 - 44.9
44.9 - 67.4
59.9 - 89.9
89.9 - 135
120 - 180
SCRd
47.2
67.4
101
135
202
270
404
539
Low-emission
combustion6
40.1
57.3
85.9
115
172
229
344
458
aThe uncontrolled emission rate shown is a representative average for dual-fuel engines. The actual
uncontrolled emission rate will vary from engine to engine.
Potential NOX reductions correspond to 8,000 annual operating hours. NOX reductions for other utilization
rates can be estimated by multiplying the value in the table by the actual annual operating hours and dividing
by 8,000.
CNOX reductions for injection retard correspond to a reduction efficiency range of 20 to 30 percent from
uncontrolled levels.
NOX reductions for SCR correspond to a reduction efficiency of 90 percent.
CNOX reductions for low-emission combustion correspond to a controlled emission level of 2 g/hp-hr.
2-21
-------
consumption, and power output is presented in Table 2-11 for
diesel and dual-fuel engines.
2.2.3.1 IR. Injection timing retard in CI engines reduces
NOX emissions by the same principles as those for SI engines and
is discussed in Section 2.2.1.2. Injection timing can be
adjusted on all new or existing CI engines. Sustained NOX
reductions, however, require an electronic injection control
system to automatically adjust the timing for changes in ambient
conditions and engine load.
Available data and information provided by engine
manufacturers show that the achievable NO., reductions using IR is
Jv
engine-specific but generally ranges from 20 to 30 percent.
Based on an average uncontrolled NOX emission level for diesel
engines of 12.0 g/hp-hr (875 ppmv), the expected range of
controlled NOX emissions is from 8.4 to 9.6 g/hp-hr (610 to
700 ppmv). For dual-fuel engines, the average uncontrolled NOX
emission level is 8.5 g/hp-hr (620 ppmv) and the expected range
of controlled NOX emissions is from 6.0 to 6.8 g/hp-hr (430 to
500 ppmv).
Limited data for ignition retard show no definite trend for
CO and HC emissions for moderate levels of ignition retard in
diesel engines and a slight increase in these emissions in dual-
fuel engines. The BSFC increases with increasing levels of IR
for both diesel and dual-fuel engines. Excessive timing retard
results in combustion instability and engine misfire.
2.2.3.2 SCR. Selective catalytic reduction applies to all
CI engines and can be retrofit to existing installations except
where physical space constraints may exist. As is the case with
SI engines, however, there is limited operating experience to
date with these engines. A total of 9 SCR installations with
diesel engines and 27 installations with dual-fuel engines were
identified in the United States by catalyst vendors.
Approximately 10 overseas SCR installations with CI engines were
identified, including one fueled with heavy oil. To date there
is also little experience with SCR in variable load applications
2-22
-------
TABLE 2-11. EFFECTS OF NO CONTROL TECHNIQUES ON
DIESEL AND DUAL-FUEL ENGINES
DIESEL ENGINES
Control technique
IR
SCR
Effect on CO
emissions
variedb
minimal
Effect on HC
emissions
varied0
minimal
Effect on
fuel consumption
0 to 5 percent
increase
0.5 percent
increase
DUAL-FUEL ENGINES
IR
SCR
L-E
increase
(13 to 23 percent)
minimal
varied6
increase
(6 to 21 percent)
minimal
varied6
0 to 3 percent
increase
0.5 percent
increase
0 to 3 percent
increase
Effect on power
output*
none"
1 to 2 percent
reduction
none
1 to 2 percent
reduction
none
aAt rated load.
"Ranged from a 13.2 percent decrease to a 10.8 percent increase for limited test results.
cRanged from a 0 to 76.2 percent increase for limited test results.
"Severe adjustment or retard may reduce power output.
eMay be slight increase or decrease, depending on engine model and manufacturer.
2-23
-------
due to ammonia injection control limitations, as discussed in
Section 2.2.2.4.
Some base-metal catalysts utilize a guard bed upstream of
the catalyst to catch heavy hydrocarbons that would otherwise
deposit on the catalyst and mask the active surface. In the past
some catalysts were also susceptible to poisoning by sulfur (the
maximum sulfur content of No. 2 diesel oil is 0.5 percent), but
sulfur-resistant catalyst formulations are now available.
Zeolite catalyst vendors typically guarantee a NOX reduction
efficiency for CI engines of 90 percent or higher, with an
ammonia slip of 10 ppmv or less. Base-metal catalyst vendors
quote guarantees for CI engines of 80 to 90 percent NOX
reduction, with ammonia slip levels of 10 ppmv or less. Based on
an average uncontrolled NOX emission level of 12.0 g/hp-hr
(875 ppmv) for diesel engines, the expected range of controlled
NOX emissions is from 1.2 to 2.4 g/hp-hr (90 to 175 ppmv). For
dual-fuel engines, the average uncontrolled NOX emission level is
8.5 g/hp-hr (620 ppmv) and the expected range of controlled NOX
emissions is from 0.8 to 1.7 g/hp-hr (60 to 125 ppmv).
Limited emission test data show NOX reduction efficiencies
of approximately 88 to 95 percent for existing installations,
with ammonia slip levels ranging from 5 to 30 ppmv. Carbon
monoxide and HC emission levels are not affected by implementing
SCR. The engine BSFC increases approximately l to 2 percent due
to the backpressure on the engine caused by the catalyst reactor.
2.2.3.3 L-E. No L-E designs were identified for diesel
engines, but L-E is available from engine manufacturers for a
limited number of dual-fuel engines. Where available, these
designs generally apply to both new engines and retrofit
applications. Like SI engines, the L-E designs use a PCC (see
Section 2.2.1.6), which ignites a very lean mixture in the main
chamber. The pilot diesel oil is reduced from 5 to 6 percent of
the total fuel delivery of conventional designs to approximately
1 percent, and is injected into the PCC. Engine modifications
required for retrofit applications are similar in scope to a
major engine overhaul, and may also require modifications or
2-24
-------
replacement of the turbocharger and intake and exhaust systems to
supply the increased volume of combustion air required for L-E.
Controlled NOV emission levels for L-E reported by
Jv
manufacturers are generally in the 2 g/hp-hr (140 ppmv) range,
although lower levels may be quoted on a case-by-case basis.
Emission test reports show controlled emission levels ranging
from l.O to 2.0 g/hp-hr (70 to 140 ppmv). These controlled
emission levels apply only to the dual-fuel operating mode; the
emissions from the diesel operating mode are not reduced.
Information provided by manufacturers shows that BSFC increases
slightly for L-E compared to conventional engines. The effect of
L-E on CO and HC emissions varies by engine manufacturer, and no
definite trend could be established from the limited data
available.
2.3 CONTROL TECHNIQUES COSTS AND COST EFFECTIVENESS
Total capital and annual costs and cost effectiveness for
the control techniques are presented in this section, in 1993
dollars, for each engine type. Costs and cost effectiveness for
rich-burn and lean-burn SI engine control techniques are
presented in Sections 2.3.1 and 2.3.2, respectively. Sections
2.3.3 and 2.3.4 present costs and cost effectiveness for diesel
and dual-fuel engines, respectively.
Total capital costs include the purchased equipment costs
and direct and indirect installation costs. Total annual costs
consist of direct operating costs (materials and labor for
maintenance, operation, incremental fuel and utilities, and
consumable material replacement and disposal) and indirect
operating costs (plant overhead, general administration, and
recovery of capital costs). These cost components are discussed
in Chapter 6.
The total capital costs for parametric adjustment control
techniques (i.e., AF, IR, or a combination of these controls)
include the cost of installing automatic control systems. The
necessary hardware and control equipment to implement these
control techniques are described in Chapter 6. Some existing
2-25
-------
installations may already have provisions for automatic controls,
and for these engines the capital and annual costs and cost
effectiveness for parametric adjustments would be considerably
lower than the figures presented in this chapter.
Cost effectiveness for each control technique is calculated
by dividing the total annual cost by the annual NOX reduction and
is stated in units of dollars per ton of NOX removed ($/ton).
The cost-effectiveness figures presented in this chapter
correspond to 8,000 annual operating hours. Lower utilization
rates (i.e., fewer annual operating hours) result in higher cost
effectiveness, and cost-effectiveness figures for other
utilization rates are presented in Chapter 6. The controlled NOX
emission levels for each control technique used to calculate cost
effectiveness are also included in Chapter 6.
2.3.1 Costs and Cost Effectiveness for Rich-Burn SI Engines
Total capital and annual costs and cost-effectiveness
figures for control techniques applied to rich-burn SI engines
are presented in Figures 2-1, 2-2, and 2-3, respectively, and are
summarized in Table 2-12. Dual plots are used where necessary to
expand the Y-axis to provide separation of curves with close
proximity.
2.3.1.1 Capital Costs. Capital costs are presented in
Figure 2-1 and are lowest for parametric adjustment controls,
ranging from $11,500 to $50,000, followed by PSC® and NSCR, which
range from $20,000 to $250,000.
When comparing the costs for PSC® and NSCR, the following
should be noted:
1. No PSC® applications were identified for engines above
approximately 2,000 hp.
2. Costs for PSC® were extrapolated for engines over
1,400 hp because costs were not available for larger engines.
3. Implementing PSC® may result in a derate in engine power
output of up to 20 percent, according to the supplier. Power
derate was not included in the economic analysis for this or any
other control technique due to the potential variation in the
extent of the derate and the difficulty in quantifying the value
2-26
-------
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
(5 1000 2CkX) 3CJOO 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Figure 2-1.
Total capital costs for NOX control techniques
applied to rich-burn SI engines.
2-27
-------
1000 2CIOO 3CIOO 4CIOO 5ClOO 6000 7tiOO 8000
POWER OUTPUT, HP
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Figure 2-2. Total annual costs for NO control techniques
applied to rich-burn SI engines (8,000 hr/yr).
2-28
-------
3500
0
Q
UJ
LU
CC
x
3500
3000-
2500
CO
CO
S2000
1500
5 1000
500
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Medium-and High-
Speed Engines
0 1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Figure 2-3. Cost effectiveness for NO^ control techniques
applied to rich-burn engines (8)000 hr/yr).
2-29
-------
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2-30
-------
of lost product. The associated cost of any power derate should
be considered on a case-by-case basis and added to the costs
shown for PSC®.
The capital costs for L-E retrofit range from 539,000 to
$756,000 for medium-speed engines ranging in size from 80 to
4,000 hp. For low-speed engines, the capital costs range from
$343,000 to $3,100,000 for engines ranging in size from 80 to
8,000 hp.
2.3.1.2 Total Annual Costs for Rich-Burn SI Engines. Total
annual costs are shown in Figure 2-2 and for parametric
adjustments range from $6,300 to $138,000. Parametric
adjustments have the lowest total annual costs, primarily because
of their relatively low capital costs. The total annual costs
for PSC® and NSCR are comparable, especially for engines rated at
2,000 hp or less, ranging from $70,000 to $111,000. For engines
over 2,000 hp, the total annual costs for PSC® range from $90,000
to $150,000, and for NSCR range from $110,000 to $244,000. The
total annual costs for L-E retrofit of medium-speed engines are
comparable to or lower than either PSC® or NSCR for engines up to
approximately 2,500 hp, ranging from $12,000 to $114,000. The
total annual costs are higher for L-E retrofits for medium-speed
engines over 2,500 hp, ranging to $177,000 for a 4,000 hp engine,
but as noted above, these engines are generally rated at less
than 2,800 hp. The highest total annual costs are for L-E
retrofits for low-speed engines, ranging from $85,000 to
$737,000.
2.3.1.3 Cost Effectiveness for Rich-Burn SI Engines. Cost
effectiveness for control techniques applied to rich-burn SI
engines is shown in Figure 2-3. Figure 2-3 shows that, despite
the wide range of capital and annual costs for the control
techniques, the range of cost effectiveness, in $/ton of NOV
Ji
removed, is comparable for all control techniques. In general,
this is because the control techniques with the lowest capital
and annual costs achieve the lowest NOX reductions, and the
control techniques with the highest capital and annual costs
generally achieve the highest NOV reductions.
Jt
2-31
-------
For parametric adjustments, the cost effectiveness ranges
from a high of $2,900/ton for the smallest engines (80 hp) to
under $l,000/ton for engines larger than approximately 250 hp.
For engines larger than 2,500 hp, the cost effectiveness for
parametric adjustments is less than $500/ton. The cost
effectiveness for NSCR and PSC® with and without turbocharger
modifications is comparable, ranging from $1,300 to $7,400 per
ton for engines up to 500 hp and less than $3,000/ton for engines
larger than approximately 250 hp (the cost effectiveness axis in
Figure 2-7 is limited to $3,500/ton for greater clarity in the 0
to $3,000/ton range). The cost effectiveness for either PSC* or
NSCR is less than $l,000/ton for engines larger than 800 hp and
decreases further to below $500/ton for engines above 1,800 hp.
For L-E, the cost effectiveness for medium-speed engines ranges
from a high of $l,200/ton for an 80 hp engine to $500/ton or less
for engines greater than 500 hp. The cost effectiveness range
for L-E retrofit is considerably higher for low-speed engines due
to the higher capital costs involved and ranges from a high of
$8,800/ton for an 80 hp engine to $2,000/t?n for a 500 hp engine.
The cost effectiveness is $2,000/ton or less for L-E retrofit for
engines greater than 2,000 hp.
2.3.2 Costs and Cost Effectiveness for Lean-Burn SI Engines
Total capital and annual costs and cost-effectiveness
figures for control techniques applied to lean-burn SI engines
are presented in Figures 2-4, 2-5, and 2-6, respectively, and are
summarized in Table 2-13. Dual plots are used where necessary to
expand the Y-axis to separate curves with similar cost-
effectiveness ranges.
2.3.2.1 Capital Costs. Capital costs are presented in
Figure 2-4 and are lowest for parametric adjustment controls,
ranging from $12,000 to $24,000 for IR and $74,000 to $130,000
for AF. The cost for AF applied to lean-burn engines includes
turbocharger modifications and is considerably higher than AF for
rich-burn engines. Where AF can be implemented for lean-burn
engines without the requirement for turbocharger modifications,
2-32
-------
160
140-
0
Figure 2-4.
IR
466
POWER OUTPUT, HP
(Thousands)
10
12
466
POWER OUTPUT, HP
(Thousands)
10
12
Total capital costs for NOX control techniques
applied to lean-burn SI engines.
2-33
-------
4 fe
POWER OUTPUT, HP
(Thousands)
Figure 2-5. Total annual costs for NOX control techniques
applied to lean-burn SI engines (8,000 hr/yr).
2-34
-------
0 4000
ai
§ 3500
3000
2500
2000
1500
co
CO
01
III
I
LL
HI
to
1000-
500
0
7000
4 6 6
POWER OUTPUT, HP
(Thousands)
10
12
Medium- and HUvSpeed Eng
466
POWER OUTPUT, HP
(Thousands)
10
12
Figure 2-6. Cost effectiveness for NOX control techniques
applied to lean-burn SI engines (8,000 hr/yr).
2-35
-------
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2-36
-------
the costs would be comparable to those shown for rich-burn AF in
Section 2.3.1.1.
The total capital costs for SCR range from $324,000 to
$1,110,000. The total capital costs for L-E retrofit range from
$61,000 to $756,000 for medium-speed engines ranging in size from
200 to 4,000 hp. For low-speed engines, the capital costs range
from $385,000 to $4,150,000 for engines ranging in size from 200
to 11,000 hp.
2.3.2.2 Total Annual Costs for Lean-Burn SI Engines. Total
annual costs are shown in Figure 2-5. Annual costs for IR range
from $7,200 to $81,000 and for AF range from $22,000 to $106,000.
For SCR, the annual costs range from $180,000 to $717,000. The
annual costs for L-E applied to medium-speed engines range from
$15,000 to $158,000 for engines up to 4,000 hp and for low-speed
engines range from $94,000 to $935,000 for engines up to
11,000 hp.
2.3.2.3 Cost Effectiveness for Lean-Burn SI Engines. Cost
effectiveness for control techniques applied to lean-burn SI
engines is shown in Figure 2-6. As is the case for rich-burn
engines, despite the wide range of capital and annual costs for
the control techniques, the range of cost effectiveness, in $/ton
of NOX removed, is generally comparable for all control
techniques. For parametric adjustments, the cost effectiveness
ranges from a high of $3,700/ton for the smallest engines
(200 hp) to under $l,000/ton for engines larger than
approximately 1,000 hp. For L-E applied to medium-speed engines,
the cost effectiveness ranges from a high of $590/ton for a
200 hp engine to $500/ton or less for engines larger than 500 hp.
The cost effectiveness for SCR ranges from $490 to $6,800 per ton
and for L-E retrofit to low-speed engines ranges from $650 to
$3,600 per ton. The cost effectiveness for SCR and L-E retrofit
to low-speed engines is comparable for engines above
approximately 2,000 hp and is less than $l,000/ton for either
control technique for engines in this size range.
2-37
-------
2.3.3 Costs and Cost Effectiveness for Diesel Engines
Total capital and annual costs and cost-effectiveness
figures for control techniques applied to diesel engines are
presented in Figures 2-7, 2-8, and 2-9, respectively, and are
summarized in Table 2-14.
2.3.3.1 Capital Costs. Capital costs are presented in
Figure 2-7 and range from $12,000 to $24,000 for IR and from
$195,000 to $967,000 for SCR.
2.3.3.2 Total Annual Costs for Diesel Engines. Total
annual costs are shown in Figure 2-8. Annual costs for IR range
from $6,200 to $78,000 and for SCR range from $145,000 to
$523,000.
2.3.3.3 Cost Effectiveness for Diesel Engines. Cost
effectiveness for NOX control techniques applied to diesel
engines is shown in Figure 2-9. For IR, cost effectiveness
ranges from a high of $2,900/ton for an 80 hp engine to $370/ton
for an 8,000 hp engine and is under $l,000/ton for engines larger
than approximately 400 hp. The cost effectiveness for SCR ranges
from $6SC to $19,000 per ton (the cost effectiveness axis in
Figure 2-9 is limited to $8,000 for greater clarity in the 0 to
$3,000 range). For engines larger than 750 hp, the cost
effectiveness for SCR is $3,000/ton or less and is less than
$l,000/ton for engines larger than 3,200 hp.
2.3.4 Costs and Cost Effectiveness for Dual-Fuel Engines
Total capital and annual costs and cost-effectiveness
figures for control techniques applied to duel-fuel engines are
presented in Figures 2-10, 2-11, and 2-12, respectively, and are
summarized in Table 2-15. Dual plots are used where necessary to
expand the Y-axis to separate curves with similar cost-
effectiveness ranges.
2.3.4.1 Capital Costs. Total capital costs are presented
in Figure 2-10 and are lowest for IR, ranging from $12,000 to
$24,000. The total capital costs for SCR range from $255,000 to
$967,000. The capital costs for L-E retrofit for dual-fuel
engines range from $720,000 to $4,000,000 for engines ranging in
size from 700 to 8,000 hp.
2-38
-------
1000
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Figure 2-7. Total capital costs for NOX control techniques
applied to diesel engines.
2-39
-------
600
1000 2000 3000 4000 5000 6000 7000
POWER OUTPUT, HP
8000
Figure 2-8. Total annual costs for NO., control techniques
applied to diesel engines (8,000 hr/yr).
2-40
-------
0
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Figure 2-9. Cost effectiveness for NOX control techniques
applied to diesel engines (8,000 hr/yr).
2-41
-------
TABLE 2-14. COSTS AND COST EFFECTIVENESS SUMMARY FOR N03
CONTROL TECHNIQUES APPLIED TO DIESEL ENGINES
Total capital costs ($1,000)
Engine size, hp
80-500
501-1,000
1,001-2,500
2,501-4,000
4,001-8,000
IR
12
12-16
16-24
24
24
SCR
195-236
236-285
285-431
431-577
577-967
Total annual costs ($l,000)a
80-500
501-1,000
1,001-2,500
2,501-4,000
4,001-8,000
6.2-10
10-16
16-32
32-46
46-78
145-165
165-184
184-261
261-332
332-523
Cost effectiveness ($/ton)a
80-500
501-1,000
1,001-2,500
2,501-4,000
4,001-8,000
770-2,900
590-770
450-590
440-450
370-440
3,500-19,000
2,000-3,500
1,100-2,000
880-1,100
690-880
L8,000 hr/yr.
2-42
-------
Cfl
1000
900
800
700
600
500
400
300
200
100J
0
IR
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
1000 2000 3000 4000 5000 6000 7000 8000
POWER OUTPUT, HP
Figure 2-10. Total capital costs for NO^ control techniques
applied to dual-fuel engines.
2-43
-------
0 1000 2000 3000 4000 5000 6000 7000 . 8000
POWER OUTPUT, HP
Figure 2-11. Total annual costs for NO control techniques
applied to dual-fuel engines (8,000 hr/yr).
2-44
-------
0
1000 2000 3000 4000 5000
POWER OUTPUT, HP
6000 7000 8000
Figure 2-12. Cost effectiveness for NO control techniques
applied to dual-fuel engines (8,000 hr/yr).
2-45
-------
TABLE 2-15. COSTS AND COST EFFECTIVENESS SUMMARY FOR
N0y CONTROL TECHNIQUES APPLIED TO DUAL-FUEL ENGINES
Total capital costs ($1,000)
Engine size,
hp
700-1,000
1,001-2,500
2,501-4,000
4,001-8,000
IR
12-16
16-24
24
24
SCR
255-284
284-431
431-577
577-967
L-E
720-855
855-1,530
1,530-2,200
2,200-4,000
Total annual costs ($l,000)a
700-1,000
1,001-2,500
2,501-4,000
4,001-8,000
10-13
13-25
25-35
35-57
170-183
183-247
247-310
310-478
182-216
216-390
390-563
563-1,020
Cost effectiveness ($/ton)a
700-1,000
1,001-2,500
2,501-4,000
4,001-8,000
900-990
680-900
600-680
480-600
2,700-3,600
1,500-2,700
1,200-1,500
890-1,200
3,800-4,600
2,700-3,800
2,500-2,700
2,200-2,500
18,000 hr/yr.
2-46
-------
2.3.4.2 Total Annual Costs for Dual-Fuel Engines. Total
annual costs are shown in Figure 2-11 and for IR range from
$10,000 to $57,000 for engines rated from 700 to 8,000 hp. Total
annual costs for SCR range from $170,000 to $478,000 and for L-E
retrofit range from $182,000 to $1,020,000.
2.3.4.3 Cost Effectiveness for Dual-Fuel Engines. Cost
effectiveness for control techniques applied to dual-fuel engines
is shown in Figure 2-12. For IR, the cost effectiveness is less
than $l,000/ton for all engines sizes, ranging from a high of
$990/ton for the smallest engine (700 hp) to $480/ton for an
8,000 hp engine. The cost effectiveness for SCR ranges from $890
to $3,600 per ton and is less than $3,000/ton for engines larger
than approximately 800 hp. For L-E, the cost effectiveness
ranges from $2,200 to $4,600 per ton and is less than $3,000/ton
for engines greater than approximately 2,000 hp.
2-47
-------
3.0 DESCRIPTION OF INTERNAL COMBUSTION ENGINES
AND INDUSTRY APPLICATIONS
Stationary reciprocating internal combustion (1C) engines
are used in a wide variety of applications where mechanical work
is performed using shaft power. These engines operate on the
same principles as common automotive 1C engines. They can be
fueled with gasoline, diesel oil, natural gas, sewage (digester)
gas, or landfill gases. In some engines certain mixtures of
these fuels may be used. They can be built to meet a wide range
of speed and load requirements, installed rapidly, and
instrumented for remote operation if desired. The size of 1C
engine ranges from approximately 1 horsepower (hp,
-------
3.1 OPERATING DESIGN CONSIDERATIONS
All reciprocating 1C engines use the same basic process. A
combustible fuel-air mixture is compressed between a movable
piston and its surrounding cylinder and head and is then ignited.
The energy generated by the combustion process drives the piston
downward. The piston's linear motion is converted via a
crankshaft to rotary power. The piston returns (reciprocates),
forcing out the spent combustion (exhaust) gases, and the cycle
is repeated.
Reciprocating 1C engines are classified primarily by the
method of ignition and the type of fuel used, secondarily by the
combustion cycle and the fuel- charging method, and finally by the
horsepower produced. These parameters are discussed below.
3.1.1 Icmition Methods
Two methods of igniting the fuel-air mixture are used in 1C
engines: spark ignition (SI) and compression ignition (CD. The
ignition method is closely related to the type of fuel used and
the thermodynamic cycle involved.
All gasoline or natural gas engines (Otto Cycle) are SI
engines. The fuel is usually premixed with air in a carburetor
(for gasoline) or in the power cylinder (for gaseous fuels), then
ignited in the cylinder by a spark (electrical discharge) across
a spark plug.
All diesel-fueled engines (Diesel Cycle) are CI engines.
Air is introduced into the cylinder and compressed. High-
pressure compression raises the air temperature to the ignition
temperature of the diesel fuel. The diesel fuel is then injected
into the hot air and spontaneous ignition occurs.
There are variations of each of these two basic types of
engines. Some CI engines are designed to use both diesel oil and
gas. Injection of diesel oil into a compressed air-gas mixture
initiates combustion. Such dual-fueled engines are usually
designed to burn any diesel oil-gas mixture from 100 percent to
6 percent oil, based on heating values. Various methods of
carburetion or fuel injection are used in SI engine designs to
3-2
-------
mix gasoline or natural gas with combustion air, which is ignited
with a spark in the cylinder.2
The CI engines usually operate at a higher compression ratio
(the ratio of the cylinder volume when the piston is at the
bottom of its stroke to the volume when it is at the top) than SI
engines because fuel is not present during compression; hence
there is no danger of premature autoignition. Since engine
thermal efficiency rises with increasing pressure ratio, CI
engines are more efficient than SI engines.
3.1.2 Operating Cycles
For reciprocating 1C engines, the combustion process may be
accomplished with either a two-stroke or four-stroke cycle of the
piston, a stroke being a movement of the piston from one end of
the cylinder to the other end. Two-stroke and four-stroke
operating cycles are described below.
A two-stroke cycle completes the power cycle in one
revolution of the crankshaft, as shown in Figure 3-1. In the
first stroke, air or an air and fuel mixture is drawn or forced
into the cylinder by a low-pressure blower as the piston moves
away from the bottom of the cylinder and toward the top. As the
piston nears the top of the cylinder, the charge is compressed
and ignited. In the second stroke, the piston delivers power to
the crankshaft as it is forced downward through the cylinder by
the high gas pressure produced following ignition and combustion.
Eventually, the piston passes and uncovers exhaust ports (or
exhaust valves open), and the combustion gases exit. As the
piston begins the next cycle, exhaust gas continues to be purged
from the cylinder, partially by the upward motion of the piston
and partially by the scavenging action of the incoming fresh air.
Finally, all ports are covered again (and/or valves closed), and
the next charge of air or air and fuel is compressed in the next
cycle.
Two-stroke engines have the advantage of a higher
horsepower-to-weight ratio compared to four-stroke engines when
both operate at the same speed. In addition, when ports are used
instead of valves, the mechanical design of the engine is
3-3
-------
QMM5TMLIK
A. INTAKE PORTS COVERED
I. EMAUST VALVE OOSCS
conumoa
A. FUEL EUTOS CYUROU
IT HUeCTIOH
I. COHM6T10R IT AUTO-
IOIITIOR
A
I.
PISTON IOVES BM
ract
TO CRANKSHAFT
JL MB «J(M IRTO CTL1HK1
I. UtflBT CASES
Figure 3-1. Two-stroke, compression ignition (blower-scavenged)
1C engine cycle. Two strokes of 180° each of crankshaft
rotation, or 360° rotation per cycle.
3-4
-------
simplified. However, combustion can be better controlled in a
four-stroke engine, and excess air ratios to purge the cylinder
are not as great as in a two-stroke engine. Therefore, four-
stroke engines tend to be slightly more efficient and may emit
less pollutants (primarily unburned hydrocarbons) than two-stroke
engines.5
A four-stroke cycle completes the power cycle in two
revolutions of the crankshaft, as shown in Figure 3-2. The
sequence of events can be summarized as follows:
1. Intake stroke—The downward motion of the piston through
the cylinder in a naturally aspirated engine or an exhaust-driven
blower in a turbocharged engine draws or forces air or an air and
fuel mixture into the cylinder.
2. Compression stroke--An upward motion of the piston
compresses the air or air and fuel mixture, reducing its volume
and thereby raising its temperature. Compression ratios range
from 11:1 to 18:1 for a diesel engine and 7:1 to 10:1 for
gasoline and natural gas engines.
3. Ignition and power (expansion) stroke--Combustion of the
air-fuel mixture increases the temperature and pressure in the
cylinder, driving the piston downward and delivering power to the
crankshaft.
4. Exhaust stroke--An upward movement of the piston expels
the exhaust gases from the cylinder.
3.1.3 Charging Methods
Three methods are commonly used to introduce or charge the
air or air-fuel mixture into the cylinder(s) of an 1C engine.
These charging methods are natural aspiration, blower-scavenging,
and turbocharging or supercharging. These charging methods are
discussed below.
3.1.3.1 Natural Aspiration. A naturally aspirated engine
uses the reduced pressure created behind the moving piston during
the intake stroke to induct the fresh air charge, and two-stroke
engines subsequently use the fresh air to assist in purging the
exhaust gases by a scavenging action. This process tends to be
somewhat inefficient, however, on both counts. In particular,
3-5
-------
INTAKE
SPARK PLUS
CYLINDER
PISTON
CRANK
(AND CRANKSHAFT)
INTAKE STROKE
Intake valve opens,
thus admitting charge
of fuel and air.
Exhaust valve closed
for most of stroke.
(a)
COMPRESSION STROKE
Both valves closed.
Fuel-air mixture is
compressed by risi
piston. Spark
ignites mixture
near end
of stroke.
Connecting
Rod
(b)
Intake
Manifold'
POWER OR WORK STROKE
Fuel-air mixture burns,
increasing temperature
and pressure, and expansion
of combustion gases
drives piston down.
Both valves closed--
exhaust valve opens
near end of stroke.
Exhaust
Manifold
EXHAUST STROKE
Exhaust valve
open; exhaust
products are
displaced from
cylinder. Intake
valve opens near
end of stroke.
Exhaust
(d)
Figure 3-2. The four-stroke, spark ignition 1C engine cycle.
Four strokes of 180° each of crankshaft rotation, or 720° of
rotation per cycle.6
3-6
-------
the volume of air drawn into the cylinder by natural aspiration
is usually equal to only 50 to 75 percent of the displaced
volume.7 For two-stroke engines, a more efficient method of
charging the cylinder is to pressurize the air (or air and fuel)
with a blower, turbocharger, or a supercharger, as described
below.
3.1.3.2 Blower-Scavenging. Low-pressure air blowers are
often used to charge two-stroke engines. Such systems are
usually called blower-scavenged rather than blower-charged,
however, because the high volumetric flow rates achieved are
quite effective in purging the cylinder of exhaust gases, while
the relatively small increase in pressure produced by the blower
does not increase the overall engine efficiency nearly as much as
does supercharging or turbocharging.8
3.1.3.3 Supercharging/Turbocharging. Supercharging refers
to any method used to increase the charge density of the
combustion air. This air charging is accomplished by placing a
compressor wheel upstream of the intake air manifold. The charge
compressor is driven by either the engine crankshaft (mechanical
supercharging) or by energy recovered from the engine exhaust
(turbocharging). Turbocharging is accomplished by placing a
turbine wheel in the exhaust stream, which drives the compressor
wheel. This turbine/compressor rotor is called a turbocharger.
Turbocharging was originally introduced to overcome performance
problems incurred with engine operation at high altitudes, where
air pressure is low. The air pressurization allows a higher mass
of air to be introduced into a given cylinder. For a constant
air-to-fuel ratio, this increase in air mass allows a
corresponding increase in fuel, so the power output for a given
cylinder is increased.
Turbochargers are normally designed to increase an engine's
output to approximately 1.5 times its original power. However,
if the engine is constructed to withstand the higher internal
pressures, turbocharging can be used to raise the engine's
charging capacity, and therefore its power output, to two to
three times its naturally aspirated value.^ Turbocharging is
3-7
-------
generally offered as an option to many current naturally
aspirated or blower-scavenged SI and CI engines. Turbocharging
was noted to be the most common method of air pressurization for
stationary diesel-fueled engines in a recent study in southern
California.10
The large increase in air pressure achieved by turbochargers
and superchargers is accompanied by an increase in temperature
that, if uncontrolled, would adversely limit the amount of air
that could be charged to the cylinder at a given pressure.
Therefore, an intercooler or aftercooler (heat exchanger) is
normally used on most larger pressure-charged 1C engines to lower
the temperature of the intake air, and one is always used on
high-power, turbocharged SI engines fueled with natural gas to
prevent premature autoignition of the fuel-air mixture. The heat
exchanger is located between the turbocharger and the intake
manifold, as shown in Figure 3-3. Decreasing the temperature of
the air increases its density, allowing a greater mass of air and
higher fuel flow rates to enter the cylinder at a given pressure,
thereby incrensing power output.
3.1.3.4 Fuel Delivery. In SI engines, fuel may be
delivered by either a carburetor or a fuel injection system. A
carburetor mixes the fuel with air upstream of the intake
manifold, and this fuel/air mixture is then distributed to each
cylinder by the intake manifold. Fuel injection is a more
precise delivery system. With fuel injection, the fuel is
injected at each cylinder, either into the intake manifold just
upstream of each cylinder or directly into the cylinder itself.
All CI engines use fuel injection. Two methods of fuel
injection are commonly used. Direct injection places the fuel
directly into the cylinder and the principal combustion chamber.
These units are also called open chamber engines because
combustion takes place in the open volume bounded by the top of
the piston, the cylinder walls, and the head. Indirect
injection, in contrast, places the fuel into a small antechamber
where combustion begins in a fuel-rich (oxygen-deficient)
atmosphere and then progresses into the cooler, excess-air region
3-8
-------
Exhaust stack
Exhaust nanlfold *
Inlet air
nanlfold
Inttrcoolir
Figure 3-3. Turbocharged, intercooled, large bore 1C engine.
11
3-9
-------
of the main chamber. These latter engines are also called
divided or precombustion chamber systems.
3.2 TYPES OF FUEL
Internal combustion engines can burn a variety of fuels.
The primary fuels for SI engines are natural gas or gasoline.
Spark-ignited engines can be modified to burn other gaseous fuels
such as digester gas, landfill gas, or coal-derived gases. For
CI engines, the primary fuel is diesel oil for diesel engines and
a mixture of diesel oil and natural gas for duel-fuel engines.
Other fuels such as heavy fuel oil can be burned in some CI
engines, but their use is limited.12
3.2.1 Spark-Ignited Engines
Gasoline is used primarily for mobile and portable SI
engines. For stationary applications at construction sites,
farms, and households, converted mobile engines typically are
used because their cost is often less than an engine designed
specifically for stationary purposes.1^ In addition, mobile
engine parts and service are readily available, and gasoline is
easily transported to the site. Thus, gasoline engines are used
in some small and medium-size stationary engines applications.
Natural gas is used more than any other fuel for large
stationary 1C engines.2 Natural gas-fueled engines are used to
power pumps or compressors in gas processing plants and pipeline
transmission stations because natural gas is available in large
volumes and at low cost at such sites.
Gaseous fuels such as sewage (digester) gas and landfill gas
can be used at wastewater treatment plants or landfills where the
gas is available. These gaseous fuels can generally be used in
the same engines as natural gas.
3.2.2 Compression-Ignited Engines
Diesel fuel, like gasoline, is easily transported and
therefore is also used in small and medium-size CI engines. The
generally higher efficiencies exhibited by diesel engines make
diesel oil the most practical fuel for large engines where
operating costs must be minimized. Natural gas, however, is
3-10
-------
often less expensive than diesel fuel and may be the primary fuel
constituent in a dual-fuel CI engine.
3.3 INDUSTRY APPLICATIONS
A wide variety of applications exists for stationary
reciprocating 1C engines, and several types of engines are used.
While 1C engines are categorized by type of fuel used, air-fuel
charging method, ignition method, and number of strokes per cycle
(as discussed in Sections 3.1 and 3.2), their classification by
size is also important when considering specific applications.
The following sections describe the characteristics of engines of
various sizes and the applications of stationary 1C engines in
four broad categories: (1) oil and gas industry, (2) general
industrial and municipal usage, (3) agricultural usage, and
(4) electrical power generation.
Estimates of the engine populations, where available, are
provided for each industry category. These data are circa 1975
to 1978. Data from a limited number of engine manufacturers were
available for engine populations sold from 1985 to 1990.14~21
These data showed that for SI engines approximately 5,660,000
total hp (4,220 MW) was sold during this period for stationary
applications. The limited data provided suggest that over
75 percent of these engines were installed in continuous-duty
applications for oil and gas production, transmission, and power
generation installations.
For CI engines, definitive data were not available to
determine the installed horsepower sold from 1985 to 1990. The
limited data provided suggest that the largest market for diesel
engines under 300 hp (225 kW) is standby power generation
applications, followed by agricultural and industrial
applications. Less than 5 percent of diesel engines under 300 hp
are used in continuous power generation. Installations for
diesel engines above 300 hp are primarily power generation and
are nearly evenly divided between continuous duty and standby
applications. The data for duel-fuel engines, although limited,
suggest that these engines are used almost exclusively for power
generation, in either continuous duty or standby applications.
3-11
-------
3.3.1 Engine Sizes
Four size classes are commonly used for stationary 1C
engines: (1) very small engines, (2) small engines and
generators, (3) medium-bore engines, and (4) large-bore engines.
Although there is some overlap between the classes, the
differences tend to be more distinct when viewed on a horsepower,
power-per-cylinder, or displacement-per-cylinder basis.
Very small engines typically have single cylinders with a
bore (diameter) of 1 to 3 inches (in.), power ranges of 2 to
16 hp (1 to 12 kW), and very high crankshaft operating speeds in
the range of 3,000 to 4,000 rpm. These are typically air-cooled
gasoline engines of the type used in nonstationary applications
such as lawn and garden equipment, chain saws, recreational
vehicles, etc., but some are also used for operating small
stationary equipment, such as appliances, air compressors, etc.,
where electricity is not available.^
Small-bore engines and generators typically have one or
two cylinders of 3 to 5 in. bore each (a few have four
cylinders), 3 to 50 hp (2 to 35 kW) output (3 to 15 hp [2 to
11 kW]/cylinder), and 1,000 to 4,000 rpm operation. These are
sometimes called low-power, high-speed engines for industrial
applications. Most of these are diesel- or gasoline-fueled four-
stroke engines. Electrical power generation in remote locations
is a major application. Refrigeration compressors in trucks and
railroad cars and hydraulic pumps for trash compactors and
tractor-trailer dump trucks are other applications. 2
Medium-bore engines typically have multiple cylinders of 3.5
to 9 in. bore, 50 to 1,200 hp (35 to 900 kW) output (10 to 100 hp
[7 to 75 kW]/cylinder), and 1,000 to 4,000 rpm operation. These
are regarded as medium-power, high-speed engines. Medium-power
engines are usually fueled with either diesel oil or gasoline,
occasionally with natural gas. They have a lower power output
per cylinder than do large-bore engines and therefore require
more cylinders to achieve a given engine horsepower. The high
rotary speeds and the wide range of horsepower available make
medium-bore engines desirable for many uses, including
3-12
-------
agricultural, nonpropulsive marine, commercial, and miscellaneous
industrial applications. 2
Large-bore engines typically have multiple cylinders of 8 to
18 in. bore, 400 to 13,000 hp (300 to 9,700 kW) output (80 to
700 hp [60 to 520 kW]/cylinder), and 250 to 1,200 rpm operation,
generally considered low- to medium-speed. Large-bore, high-
power CI engines are usually four-cycle designs that can operate
on either diesel oil or a duel-fuel mixture of diesel oil and
natural gas. Large-bore SI engines are split about equally
between two- and four-cycle designs and usually operate on
natural gas. In addition, a few engines in this size class are
designed to operate interchangeably as either CI or SI depending
on fuel availability. The large-bore, low-speed engines, with
their high power output per cylinder, are more economical to
operate than medium-bore engines because of their lower fuel
consumption and longer service life. Therefore, they tend to be
used in applications requiring continuous operation, such as
municipal electrical power generation, oil and gas pipeline
transmission, and oil and gas production.22
3.3.2 Oil and Gas Industry
Stationary 1C engines are widely used in the oil and gas
industry, both in production and in transport by pipeline. Usage
tends to be concentrated in the oil- and gas-producing States in
the lower Midwest and the Gulf Coast and along the pipeline
distribution network toward the Northeast. Most of these engines
are fueled with either natural gas or diesel oil. Some dual-
fueled but few gasoline engines are used in applications in this
industry segment. Table 3-1 summarizes the use of stationary
engines in the oil and gas industry.
The transmission of natural gas relies heavily on stationary
gas-fueled engines as prime movers at pumping stations, mostly in
remote locations. This use, in turn, is currently the major
application for natural gas engines.24 Nearly 7,700 prime mover
engines of 350 hp (260 kW) capacity or greater were estimated in
1989 to be in operation at compressor stations. About 83 percent
of these engines were reciprocating 1C engines, while 17 percent
3-13
-------
TABLE 3-1. OIL AND GAS INDUSTRY APPLICATIONS
STATIONARY 1C ENGINES CIRCA 197923
OF
Fuel
Natural gas
Natural gas
Diesel oil
Diesel oil
Dual-fueled
Application
Production
Well drilling
Well pumps
Secondary recovery
Plant processing
Utility compression
Production
On-land drilling
Off-shore drilling
Transmission
Transmission
Number in use
3,050
266,000
5,600
4,000
4,500
4,000
3,050
675
500
a
Average size, hp
350
15
200
750
2,000
750
350
350
2,000
b
Average
operation, hr/yr
2,000
3,500
6,000
8,000
6,000
6,000
2,000
2,000
6,000
6,000
Number in use was calculated from annual engine production data and estimated average service for each type of
engine.
alncluded with diesel data.
bNot available.
3-14
-------
were gas turbines, which because of their larger size (1,000 to
30,000 hp [0.75 to 22.4 MW] turbines vs. 50 to 10,000 hp [0.04 to
7.5 MW] reciprocating engines) contributed about one-half of the
total capacity. Nearly 350 models of reciprocating engines are
in use in this application. Thirty percent of the engines in gas
transmission service are more than 30 years old, and 50 years'
service is not uncommon.25
Diesel engines are used extensively in on-land and off-shore
drilling and in oil pipeline pumping. In 1979, 3,050 stationary
diesel (or dual-fueled) engines were in use in on-land drilling
and 675 in off-shore drilling. These engines had an average
power rating of 350 hp (260 kW),23
3.3.3 General Industrial and Municipal Usage
The largest population of stationary reciprocating 1C
engines, in terms of numbers of units, is found in the general
industrial category, which includes construction and some
municipal water services uses. The available data showing usage
by fuel type and application as of 1979 are given in Table 3-2.
The data for diesel engines also include some unspecified
agricultural uses; presumably these might include some
compressors, pumps, standby generators, welders, etc. Small
gasoline engines (<15 hp [11 kW] ) are used most frequently in
this category. Gasoline- and diesel-fueled standby electrical
generators constitute another widely used application in this
category, but these data do not include the natural gas and
diesel/dual-fueled engines used for electric power generation
summarized later in Section 3.3.5. Gas-fueled engines for
commercial shaft power have the highest power output (2,000 hp
[1,500 kW] average) in use in this category, while large diesel
engines (200 to 750 hp [150-560 kW] average) are used in electric
power generation, construction, industrial shaft power, and waste
treatment applications.26
3.3.4 Agricultural Usage
Available data on the use of stationary 1C engines in
agriculture as of 1979 are given in Table 3-3. These data lack
3-15
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TABLE 3-2.
GENERAL INDUSTRIAL AND MUNICIPAL APPLICATIONS OF
STATIONARY 1C ENGINES CIRCA 197923
Fuel
Natural gas
Diesel oilb
Gasoline
Application
Air conditioning
Municipal water supply
Municipal waste treatment
Plant air
Shaft power, commercial
Shaft power, industrial
Construction, small
Construction, large
Compressor, portable0
Generator sets, standby
<50kw
50-400 kw
400-1000 kw
Marine, nonpropulsive
Miscellaneous, large"
Municipal water supply
Pumps
Welders
Compressors
Construction
Generator sets, >5 kw
Miscellaneous
Small, < IS hp
Welders
No. in use*
3,760
2,100
1,740
750
600
2,900
50,000
50,000
90,000
70,000
160,000
30,000
15,000
30,000
2,100
25,000
80,000
70,000
40,000
350,000
50,000
63,000,000
180,000
Average size,
hp
80
120
400
100
2,000
200
50
240
75
75
250
750
100
750
120
100
100
55
150
55
55
4
55
Average
operation, hr/yr
2,000
3,000
4,000
4,000
1,000
5,000
500
500
500
500
250
100
3,500
100
3,000
1,000
500
400
500
400
400
50
400
aNumber in use was calculated from annual engine production data and estimated average service for each type of
engine.
"Includes some agricultural uses.
cDoes not include mobile refrigeration units.
"Includes pumps, snow blowers, aircraft turbine starters, etc.
3-16
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TABLE 3-3. AGRICULTURAL APPLICATIONS OF
STATIONARY 1C ENGINES CIRCA 197923
Fuel
Natural gas
Diesel oil
Gasoline
Application
All
Compressors, pumps,
standby generators,
welders, etc.
Irrigation
Misc. machinery0
Number
in usea
91,000
b
10,000
400,000
Average
size,
hp
100
b
100
30
Average
operation,
hr/yr
2,500
b
2,000
200
&Number in use was calculated from annual engine production data and estimated average service for each type of
engine.
bData were included in general industrial category, Table 3-2.
clncludes some mobile equipment such as combines, balers, sprayers, dusters, etc.
3-17
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the degree of detail available for the oil and gas industry and
general industrial categories.
Small to medium-size gasoline engines (30 hp [22 kW]
average) for "miscellaneous machinery11 constitutes the largest
use class, while those used in pumping service for irrigation are
larger (100 hp [75 kW] average). Other uses would include frost
and pest control, harvester-mounted auxiliary power, and some
remote and standby electricity generation where electric motors
do not meet the need.^
Some natural gas- and diesel-fueled engines are also used,
but data for the latter are not available separate from those
given in Table 3-2 for general industrial applications.
3.3.5 Electric Power Generation
Electric power generation is one area in which stationary
reciprocating 1C engines do not compete with electric motors.
The available installation data as of 1979 for electric power
generation by natural gas, diesel, and dual-fuel engines is shown
in Table 3-4. These data do not include smaller generators used
to supply power locally for industrial and agricultural equipment
or for standby/emergency needs in those industries. In some
cases, the demarcation between categories cannot be discerned
with certainty from the available data.
The data in Table 3-4 indicate that gas-fueled engines used
to operate emergency/standby generators were the largest
application, in terms of units in service (2,000) in this
category in 1979. Information provided by diesel engine
manufacturers suggests that many small diesel engines have been
installed in standby power generation applications. One
manufacturer reported total sales of approximately 1 million hp
between 1985 and 1990 for diesel engines of 300 hp (225 KW) or
less for standby power generation. The South Coast Air Quality
Management District has permitted more than 400 diesel engines
for standby power generation.10 The engine/generator sets are
installed at hospitals, banks, insurance companies, and other
facilities where continuity of electrical power is critical.
This reference states that these are typically medium-power
3-18
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TABLE 3-4. ELECTRICAL POWER GENERATION BY STATIONARY
1C ENGINES CIRCA 197923
Fuel
Natural gas
Diesel oilb
Dual-fueled
Gasoline
Application
Emergency/standby
Industrial on-site
Commercial/institutional
Private/public utility
All
All
e
No.
in use*
2,000
1,500
450
b
400
d
e
Average Size,
hp
100
300
200
b
2,500
b
e
Average
operation,
hr/yr
50
4,000
4,000
b
2,600
b
e
Output,
million
hp-hr/yr x 106
9
1,080
162
166
2,160
6,000
e
'Number in use was calculated from annual engine production data and estimated average service for each type of engine.
bNot available.
cDoes not include generators counted in general industrial usage, Table 3-2.
^Included with diesel data.
eSee general industrial (Table 3-2) and agricultural (Table 3-3) applications.
3-19
-------
(100 hp [75 kW]/cylinder), high-speed (1,000 rpm), four-cycle
engines that are turbocharged and after-cooled.
The data in Table 3-4 show that the diesel and dual-fueled
engines are by far the largest (2,000 hp [1,500 kW] average) used
for electrical generation, but they do not provide details of
specific applications. Dual-fuel, large-bore CI engines are used
almost exclusively for prime electrical power generation in order
to take advantage of the economy of natural gas and the
efficiency of the diesel engine.27
3.4 REFERENCES
1. Stationary Internal Combustion Engines, Standards Support
and Environmental Impact Statement, Volume I: Proposed
Performance Standards. Publication No. EPA 450/2-78-125a.
U. S. Environmental Protection Agency, Research Triangle
Park, NC. July 1979. pp. 3-1 through 3-9.
2. Acurex Corporation. Environmental Assessment of Combustion
Modification Controls for Stationary Internal Combustion
Engines. Publication No. EPA-600/7-81-127. U. S.
Environmental Protection Agency, Research Triangle Park, NC.
July 1981. pp. 3-2 through 3.3.
3. Reference 1, p. 3-23.
4. Reference 1, p. 3-28.
5. Reference 1, pp. 3-27 through 3-29.
6. Obert, E. F. Internal Combustion Engines and Air Pollution
Control. Intext Educational Publishers, New York. 1973.
7. Reference 2, p. 3-5.
8. Reference 2, p. 3-7.
9. Reference l, p. 4-102.
10. Permit Processing Handbook, Volume 1. Engineering Division,
South Coast Air Quality Management District. Los Angeles.
August 18, 1989.
11. Reference 1, p. 4-103.
12. Salvesen, F. G., et al. Emissions Characterization of
Stationary NOX Sources: Volume I--Results. Publication No.
EPA-600/7-78-12a. U. S. Environmental Protection Agency,
Research Triangle Park, NC. June 1978.
3-20
-------
13. Roessler, W. U., et al. Assessment of the Applicability of
Automotive Emission Control Technology to Stationary
Engines. Publication No. EPA-650/2-74-051. U. S.
Environmental Protection Agency, Research Triangle Park, NC.
July 1974.
14. Letter and attachments from Stachowitz, R.W.,
Dresser-Waukesha, WI, to Snyder, R. B., MRI. September 16,
1991. Response to internal combustion engine questionnaire.
15. Letter and attachments from Kasel, E., Fairbanks Morse
Division of Colt Industries, Beloit, WI, to Snyder, R. B.,
MRI. September 9, 1991. Response to internal combustion
engine questionnaire.
16. Letter and attachments from McCormick, W. M., Cooper Ajax-
Superior, Springfield, OH, to Snyder, R. B., MRI. September
16, 1991. Response to internal combustion engine
questionnaire.
17. Letter and attachments from Axness, J., Deere Power Systems
Group, Waterlook, IA, to Snyder, R. B., MRI. August 30,
1991. Response to internal combustion engine questionnaire.
18. Letter and attachments from Miklos, R., Cooper-Bessemer,
Grove City, PA, to Snyder, R. B., MRI. September 27, 1991.
Response to internal combustion engine questionnaire.
19. Letter and attachments from locco, D., Dresser-Rand, Painted
Post, NY, to Snyder, R. B., MRI. October 1, 1991. Response
to internal combustion engine questionnaire.
20. Letter and attachments from Dowdall, D. C., Caterpillar
Inc., to Jordan, B. C., EPA/ESD. March 25, 1992. Internal
combustion engines.
21. Letter and attachments from Fisher, J., Detroit Diesel
Corporation, to Jordan, B. C., EPA/ESD. June 10, 1992.
Internal combustion engines.
22. Reference 2, pp. 3-8 through 3-11.
23. Reference 1, pp. 3-14 through 3-17.
24. Urban, C. M., H. E. Dietzmann, and E. R. Fanick. Emission
Control Technology for Stationary Natural Gas Engines.
Journal of Engineering for Gas Turbines and Power. Ill;
369-374, July 1989.
25. Castaldini, C. (Acurex Corporation). NOX Reduction
Technology for Natural Gas Industry Prime Movers; Special
Report. Prepared for Gas Research Institute. Publication
No. GRI-90/0215. August 1990.
3-21
-------
26. Reference 1, pp. 3-14 and 3-15.
27. Compilation of Air Pollutant Emission Factors—Stationary
Point and Area Sources, AP-42, 4th edition, Volume I.
Section 3.2, Stationary Internal Combustion Sources. U. S.
Environmental Protection Agency, Research Triangle Park, NC.
September 1985.
3-22
-------
4.0 CHARACTERIZATION OF NOX EMISSIONS
This chapter discusses the formation of NOX emissions in
reciprocating internal combustion (1C) engines. Section 4.1
describes how NOX and other emissions are formed during the
combustion process. Factors that influence the rate of formation
of NO., and other emission are discussed in Section 4.2.
Jt
Uncontrolled emission factors are presented in Section 4.3.
References for this chapter are listed in Section 4.4.
4.1 FORMATION OF EMISSIONS
The primary focus of this document is NOX emissions, and the
formation of NO-, is discussed in Section 4.1.1. Efforts to
JV.
reduce NOX emissions can affect the formation of carbon monoxide
(CO) and hydrocarbons (HC), however, and the formation of these
emissions is briefly presented in Section 4.1.2.
4.1.1 The Formation of NOX
The combustion of an air/fuel mixture in the cylinder of an
1C engine results in the dissociation of nitrogen (N2) and oxygen
(02) into N and 0, respectively. Reactions following this
dissociation result in seven known oxides of nitrogen: NO, N02,
N03, N20, N203, N204, and N205. Of these, nitric oxide (NO) and
nitrogen dioxide (N02) are formed in sufficient quantities to be
significant in atmospheric pollution.1 In this document, "NOX"
refers to either or both of these gaseous oxides of nitrogen.
Virtually all NOX emissions originate as NO. This NO is
further oxidized in the exhaust system or later in the atmosphere
to form the more stable N02 molecule. There are two mechanisms
by which NOX is formed in an 1C engine: (1) the oxidation of
atmospheric nitrogen found in the combustion air (thermal NOX)
and (2) the conversion of nitrogen chemically bound in the fuel
4-1
-------
(fuel NOX, or organic NOX) . These mechanisms are discussed
below.
4.1.1.1 Formation of Thermal NOX. Thermal NOX is formed in
the combustion chamber when N2 and 02 molecules dissociate into
free atoms at the elevated temperatures and pressures encountered
during combustion and then recombine to form NO by the Zeldovich
mechanism. The simplified reactions are shown below:3
02 «- 20
O + N2 " NO + N
N + 02 *• NO + O
The reaction rate toward NO formation increases exponentially
with temperature. The NO further oxidizes to N02 and other NOX
compounds downstream of the combustion chamber.
4.1.1.2 Formation of Fuel NO^. Fuel NOX (also known as
organic NOX) is formed when fuels containing nitrogen are burned.
Nitrogen compounds are present in coal and petroleum fuels as
pyridine-like (C5H5N) structures that tend to concentrate in the
heavy resin and asphalt fractions upon distillation. Some low-
Brit^sh thermal unit (Btu) synthetic fuels contain nitrogen in
the form of ammonia (NH^) , and other low-Btu fuels such as sewage
and process waste- stream gases also contain nitrogen. When these
fuels are burned, the nitrogen bonds break and some of the
resulting free nitrogen oxidizes to form NOX.3 With excess air,
the degree of fuel NOX formation is primarily a function of the
nitrogen content in the fuel. The fraction of fuel -bound
nitrogen (FBN) converted to fuel NOX decreases with increasing
nitrogen content, although the absolute magnitude of fuel NOX
increases. For example, a fuel with 0.01 percent nitrogen may
have 100 percent of its FBN converted to fuel NOX, whereas a fuel
with a 1.0 percent FBN may have only a 40 percent fuel NOX
conversion rate. While the low-percentage -FBN fuel has a
100 percent conversion rate, its overall NOX emission level would
be lower than that of the high-percentage FBN fuel with a
40 percent conversion rate.4
Nitrogen content varies from 0.1 to 0.5 percent in most
residual oils and from 0.5 to 2 percent for most U.S. coals.
4-2
-------
Traditionally, most light distillate oils have had less than
0.015 percent nitrogen content by weight. However, today many
distillate oils are produced from poorer-quality crudes,
especially in the northeastern United States, and these
distillate oils may contain percentages of nitrogen exceeding the
0.015 threshold. These higher nitrogen contents increase fuel
NCL, formation.6
H
Most 1C engines are presently fueled by natural gas or light
distillate oil that typically contains little or no FBN. As a
result, when compared to thermal NOX, fuel NOX is not currently a
major contributor to overall NOX emissions from most 1C engines.
4.1.2 Formation of Other Emissions
The formation of CO and HC is briefly discussed in this
section.
4.1.2.1 Carbon Monoxide (CO). Carbon monoxide is an
intermediate combustion product that forms when the oxidation of
CO to C02 cannot proceed to completion. This situation occurs if
there is a lack of available oxygen, if the combustion
temperature is too low, or if the residence time in the cylinder
is too short.
4.1.2.2 Hydrocarbons (HC). The pollutants commonly
classified as hydrocarbons are composed of a wide variety of
organic compounds. They are discharged into the atmosphere when
some of the fuel remains unburned or is only partially burned
during the combustion process. This incomplete burning usually
occurs as a result of inadequate mixing of fuel and air,
incorrect air/fuel ratios, or "quenching" of the combustion
products by the combustion chamber surfaces.4
Nonmethane hydrocarbons (NMHC) are sometimes categorized
separately from methane HC's because NMHC's react with NO,, in the
J\.
lower atmosphere, contributing to the formation of photochemical
smog. Methane does not readily react with NO., in the lower
Jv
atmosphere, so methane HC emissions are not a major concern in
some regulated areas.8
4-3
-------
4.2 FACTORS THAT INFLUENCE NOX EMISSIONS
Engine design and operating parameters, type of fuel, and
ambient conditions all have an impact on NOX emissions from 1C
engines. These factors are discussed in this section.
4.2.1 Engine Design and Operating Parameters
Variations in engine design or operating parameters will
affect emissions. These parameters may be divided into five
classes: (1) air-to-fuel ratio (A/F) and charging method;
(2) ignition timing; (3) combustion chamber valve design;
(4) engine combustion cycle; and (5) operating load and speed.
4.2.1.1 Air-to-Fuel Ratio and Charging Method. The
formation rate of NOX increases with increases in combustion
temperature. Maximum temperatures occur when the A/F is just
above stoichiometric. The relationship between A/F and NOX
formation is shown in Figure 4-1. This figure shows that maximum
NOY formation rates occur in the region of stoichiometric A/F's
Jv
due to the high combustion temperatures. In any engine, as the
A/F decreases from stoichiometric, NOX formation decreases due to
a lack of excess oxygen. As the A/F increases from
stoichiometric, NOX formation first increases with the presence
of additional oxygen, then steadily decreases as the A/F
increases beyond stoichiometric.^
Emissions of CO increase sharply, as shown in Figure 4-1, at
fuel-rich A/F's due to the lack of oxygen to fully oxidize the
carbon. As the A/F is increased toward fuel-lean conditions,
excess oxygen is available and CO emissions decrease as
essentially all carbon is oxidized to C02- Emissions of HC
increase at fuel-rich A/F's because insufficient oxygen levels
inhibit complete combustion. At fuel-lean A/F's, HC emissions
increase slightly as excess oxygen cools combustion temperatures
and inhibits complete combustion.
The operational range of lean A/F's is often restricted by
the charging method. Turbocharged, fuel-injected engines have
precise A/F control at each cylinder and can operate at A/F's
approaching lean flammability limits. Naturally aspirated
engines have imprecise carbureted A/F control and must operate at
4-4
-------
5
•/»
«/>
5
14 AIR-TO- FUEL6 RATIO
Figure 4-1.
Effect of air/fuel ratio on NOX, CO, and EC
emissions.*
4-5
-------
richer A/F's to avoid excessively lean mixtures at individual
cylinders, which can result in incomplete combustion or
misfiring.10
4.2.1.2 Ignition Timing. As discussed in Chapter 3,
combustion is initiated by the injection of fuel oil in
compression-ignited engines and by a spark in spark-ignited
engines. By delaying, or retarding, the timing of ignition, the
combustion process occurs later in the power cycle. Ignition
retard, therefore, effectively increases the combustion chamber
volume, which reduces pressures in the cylinder and may lower
combustion temperatures. These changes in combustion conditions
result in lower NOX emission levels in most engines.10'11
Emissions of CO and HC are not significantly affected by timing
retard except in extreme cases where misfiring can occur.
Timing retard lowers NOX levels significantly, but the lower
combustion pressures result in reduced cycle efficiency and,
therefore, increased engine fuel consumption. Excessive smoke
may also result from moderate to high degrees of ignition retard
in diesol engines.12 Increased exhaust smoke from ignition
timing retard may result in increased soot levels in the lube
oil, which requires more frequent oil changes.11
4.2.1.3 Combustion Chamber and Valve Design. Almost any
variation in cylinder or valve design will affect emissions.
Unfortunately, the effects cannot be quantified since each engine
is different and changing some design variables may cancel any
beneficial effects of others. However, some generalizations can
be made. Design variables that improve mixing within the
cylinder tend to decrease emissions. Improvements in mixing may
be accomplished through swirling the air or fuel-air mixture
within the cylinder, improving the fuel atomization, and
optimizing the fuel injection locations. Decreasing the cylinder
compression ratio may reduce NOX emissions, especially in older
engine designs.11
The vintage and accumulated operating hours of an engine may
affect emission rates. Engine manufacturers may implement
changes to the combustion chamber and valve designs over the
4-6
-------
production life of an engine model, making emission rates
dependent upon the date of manufacture. Also, maintenance
practices can affect long-term engine performance, resulting in
changes in emission rates among otherwise identical engines.
4.2.1.4 Engine Combustion Cycle. As discussed in
Chapter 3, reciprocating 1C engines may be either two- or
four-stroke cycle. During combustion, emissions from either type
are similar.13 However, several events during the charging of a
two-cycle engine may affect emission levels. On noninjected
engines, the scavenge air, which purges the cylinder of exhaust
gases and provides the combustion air, can also sweep out part of
the fuel charge. Thus, carbureted two-cycle engines often have
higher HC emissions in the form of unburned fuel.
If the cylinder of a two-stroke engine is not completely
purged of exhaust gases, the result is internal exhaust gas
recirculation (EGR). The remaining inert exhaust gases absorb
energy from combustion, lowering peak temperatures and thereby
lowering NOX.
4.2.1.5 Effects of Load and Speed. The effect of operating
load and engine speed on emissions varies from engine to engine.
One manufacturer states that for SI engines the total NOX
emissions on a mass basis (e.g., Ib/hr) increase with increasing
power output. On a power-specific (also referred to as brake-
specific, e.g., g/hp-hr) basis, however, NOX emissions decrease
with increasing power levels.11 Test data for a second
manufacturer's SI engine shows that NOX emissions decrease with
increases in load if the engine speed decreases with decreasing
load. If the engine speed is held constant, however, brake-
specific NOX emission levels decrease with decreasing engine
load.14 In general, diesel compression ignition engines exhibit
decreasing brake-specific NOX emissions with increasing load at
constant speed. This is partly caused by changes in the A/F
ratio. Some turbocharged engines show the opposite effect of
increasing brake-specific NOY emissions as load increases.
J\.
In diesel engines, carbon monoxide emissions first decrease
with increasing load (equivalent to increasing temperature) and
4-7
-------
then increase as maximum load is approached. Brake-specific HC
emissions decrease with increasing load as a result of increasing
temperature. For naturally aspirated engines, smoke emissions
generally reach their maximum at full load. Turbocharged
engines, however, offer the potential to optimize the engine at
full load and minimize smoke emissions at full load. Natural gas
engines follow the same trends as diesel engines for HC and CO.10
As this discussion indicates, the effect of engine load and speed
on NOX, CO, and HC emissions is engine-specific.
4.2.2 Fuel Effects
As discussed in Section 4.1.1, overall NOX emissions are the
sum of fuel NOX and thermal NOX. Fuel NOX emissions increase
with increases in FBN content, and using residual or crude oil
increases fuel NOX and hence total NOX emissions. Similarly,
using gaseous fuels with significant FBN contents such as coal
gas or waste stream gases increases NOX emissions when compared
to natural gas fuel. Quantitative effects were not available.
Thermal NOX levels are also influenced by the type of fuel.
Landfill and digester (or sewage) gases and propane are examples
of alternate fuels for SI engines, and the relative emission
levels for landfill gas, propane, and natural gas are shown in
Figure 4-2. Landfill and digester gases have relatively low Btu
contents compared to those of natural gas and propane and
therefore have lower flame temperatures, which result in lower
NO., emissions. Because the stoichiometric A/F is different for
J^
each gas, emissions are shown in Figure 4-2 as a function of the
excess air ratio rather than A/F. The excess air ratio is
defined as:
Excess air ratio (A) = . */F actual .
A/F stoichiometric
Figure 4-2 shows that the effect of alternative fuels is
greatest at A/F's from near-stoichiometric to approximately 1.4,
which is within the operating range of rich-burn and lean-burn
SI engine designs. The effect of alternate fuels on emissions is
minimal for low-emission engine designs that operate at higher
4-8
-------
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A/F's and relatively low combustion temperatures. Fuel effects
on CO emissions, as shown in Figure 4-2, are minimal.15
4.2.3 Ambient Conditions.
The effects of atmospheric conditions on NOX emissions have
been evaluated by several sources, predominately by or for
automotive engine manufacturers. These test results indicate
changes in NOX of up to 25 percent caused by ambient temperature
changes and up to 40 percent caused by ambient pressure
changes.16 Most of these effects are caused by changes in the
A/F as the density of the combustion air changes. Humidity has
an additional effect on lowering NO,, in that high-moisture
Jv
conditions reduce the peak temperatures within the engine
cylinders, decreasing NOX emissions by up to 25 percent.17
The design A/F varies for different 1C engines, so engines
respond differently to changes in atmospheric conditions. Thus
it is quite difficult to quantify atmospheric effects on engine
emissions. However, the following general effects have been
observed for engines operating close to stoichiometric
conditions:17
1. Increases in humidity decrease NOY emissions;
J\.
2. Increases in intake manifold air temperature may
increase HC and CO emissions; and
3. Decreases in atmospheric pressure increase HC and CO
emissions.
4.3 UNCONTROLLED EMISSION LEVELS
Stationary 1C engine sizes vary widely, so comparisons of
emissions among a group of engines require that emissions be
presented on a brake-specific, mass-per-unit-power-output basis.
In this document emissions are expressed in units of grams per
horsepower-hour (g/hp-hr). For conversion to parts per million
4-10
-------
by volume (ppmv) at 15 percent 02/ the following approximate
i fl
conversion factors are used in this document -,°
NOX emissions:
rich-burn engines: 1 g/hp-hr = 67 ppmv
lean-burn engines: 1 g/hp-hr = 73 ppmv
CO emissions;
rich-burn engines: 1 g/hp-hr = 110 ppmv
lean-burn engines: 1 g/hp-hr * 120 ppmv
HC emissions;
rich-burn engines: 1 g/hp-hr « 194 ppmv
lean-burn engines: 1 g/hp-hr = 212 ppmv
Uncontrolled emission levels were provided by several engine
manufacturers. These emissions levels were tabulated and
averaged for engines with similar power ratings. The range of
NOV emissions and the average for engine size categories from 0
Jt
to 4,000+ hp are shown in Table 4-1. Most manufacturers provided
emission data only for current production engines, but some
included older engine lines as well. For rich-burn engines, the
average NO., emission level ranges from 13.1 to 16.4 g/hp-hr
J\.
(3.54 to 4.87 pounds/million Btu's [Ib/MMBtu]). For lean-burn
engines, the average ranges from 7.9 to 18.6 g/hp-hr (1.99 to
5.46 Ib/MMBtu). The 7.9 g/hp-hr shown for the smallest lean-burn
engine category is considerably lower than for the other lean-
burn engines. This figure reflects unusually low NOX emissions
reported for one manufacturer's line of engines. Excluding this
engine line yields emission levels similar to those shown for
other lean-burn engine categories (i.e., 17.0 to 17.5 g/hp-hr).
For diesel engines, NOX emissions range from 11.2 to 13.0 g/hp-hr
(3.66 to 4.26 Ib/MMBtu). Dual-fuel engines have the lowest NOX
emission rates, ranging from 4.9 to 10.7 g/hp-hr (1.75 to
3.26 MMBtu).
4-11
-------
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4.4 REFERENCES FOR CHAPTER 4
1. Control Techniques for Nitrogen Oxides Emissions From
Stationary Sources - Revised Second Edition.
U. S. Environmental Protection Agency, Research Triangle
• Park, NC. Publication No. EPA-450/3-83-002. January 1983.
p. 2-1.
2. Stationary Internal Combustion Engines. Standards Support
and Environmental Impact Statement, Volume I: Proposed
Standards of Performance. U. S. Environmental Protection
Agency, Research Triangle Park, NC. Publication
No. EPA-450/2-78-125a. July 1979. p. 4-3.
3. Radian Corporation. Internal Combustion Engine NO.. Control.
Prepared for the Gas Research Institute (Chicago, TL) and
the Electric Power Research Institute (Palo Alto, CA).
Publication No. GS-7054. December 1990. 55 pp.
4. Wilkes, C. Control of NOX Emissions From Industrial Gas
Turbine Combustion Systems. General Motors Corporation.
Indianapolis, IN. For presentation at the 82nd annual
meeting and exhibition, Anaheim, CA. June 25 to 30, 1989.
p. 5.
5. Reference 2, p. 4-4.
6. Reference 2, p. 3-5.
7. Schorr, M. NOX Control for Gas turbines: Regulations and
Technology. General Electric Company. Schenectady, NY.
For presentation at the Council of Industrial Boiler Owners
NOX Control IV Conference. February 11-12, 1991. pp. 3-5.
8. Reference 2, pp. 4-5 through 4-9.
9. Reference 2, pp. 3-33, 3-34.
10. Environmental Assessment of Combustion Modification Controls
for Stationary Internal Combustion Engines.
U. S. Environmental Protection Agency, Industrial
Environmental Research Laboratory, Research Triangle Park,
NC. Publication No. EPA-600/7-81-127. July 1981. pp. 4-11
and 4-12.
11. Letter from Dowdall, D.C., Caterpillar Inc., to Neuffer,
W. J., EPA/ISB. December 17, 1992. Review of draft
reciprocating engine ACT document.
12. Reference 2, p. 4-89.
13. Reference 2, pp. 3-27 through 3-29.
4-13
-------
14. Helmich, M. J., and M. A. Schleigh. C-B Reciprocating
Cleanburn™ Update. Cooper-Bessemer Reciprocating Products
Division of Cooper Industries. Presented at the Sixth
Annual Reciprocating Machinery Conference. Salt Lake City.
September 23-26, 1991. 23 pp.
15. Sorge, G. W. Update on Emissions. Waukesha Engine Division-
-Dresser Industries, Waukesha, WI. August 1991. 17 pp.
16. Reference 2, pp. 4-11 through 4-30.
17. Reference 10, pp. 4-4, 4-5.
18. Letter and attachments from Stachowicz, R. W., Waukesha
Engine Division of Dresser Industries, Inc., to
Snyder, R. B., Midwest Research Institute. September 16,
1991. Internal combustion engines.
19. Letter and attachment from Miklos, R. A., Cooper-Bessemer
Reciprocating Products Division, to Jordan, B. C., EPA/ESD.
January 21, 1992. Internal Combustion engines.
20. Letter and attachment from Dowdall, D. C., Caterpillar Inc.,
to Jordan, B. C., EPA/ESD. March 25, 1992. Internal
combustion engines.
21. Letter and attachment from locco, D. E., Dresser-Rand, to
Snyder, R. B., Midwest Research Institute. October 1, 1991.
Internal combustion engines.
22. Letter and attachment from McCormick, W. M., Cooper
Industries--Ajax Superior Division, to Snyder, R. B.,
Midwest Research Institute. September 16, 1991. Internal
combustion engines.
23. Letter and attachment from Axness, J., Deere Power Systems
Group, to Snyder, R. B., Midwest Research Institute.
August 30, 1991. Internal combustion engines.
24. Letter and attachment from Fisher, J., Detroit Diesel
Corporation, to Jordan, B. C., EPA/ESD . June 10, 1992.
Internal combustion engines.
25. Letter and attachment from Kasel, E., Fairbanks Morse Engine
Division of Coltee Industries, to Snyder, R. B., Midwest
Research Institute. September 4, 1991. Internal combustion
engines.
4-14
-------
5.0 NOX CONTROL TECHNIQUES
This chapter describes NOX emission control techniques for
reciprocating engines. For each control technique, the process
description, extent of applicability, factors that affect the
performance, and achievable controlled emission levels are
presented. The effect of NOX reduction on carbon monoxide (CO)
and unburned hydrocarbon (HC) emissions is also discussed. Some
regulatory agencies speciate nonmethane hydrocarbon (NMHC)
emissions from total hydrocarbon (THC) emissions. Where HC
emission levels presented in this chapter are not speciated, it
is expected that the emission levels correspond to NMHC rather
than THC emissions. Emissions are stated in units of grams per
horsepower-hour (g/hp-hr) and parts per million by volume (ppmv).
The first units reported are those reported in the referenced
source; the corresponding units given in parentheses were
calculated using the conversion factors shown in Section 4.3.. It
should be noted that these conversion factors are approximate
only, and the calculated emission levels shown in parentheses
using these conversion factors are provided for information only.
Unless noted otherwise, all emission levels reported in units of
ppmv are referenced to 15 percent oxygen.
Some control techniques discussed in this chapter require
that additional equipment be installed on the engine or
downstream of the engine in the exhaust system. Issues regarding
the point of responsibility for potential engine mechanical
malfunctions or safety concerns resulting from use of the control
techniques presented are not evaluated in this document.
All 1C engines can be classified as either rich-burn or
lean-burn. A rich-burn engine is classified as one with an
5-1
-------
air-to-fuel ratio (A/F) operating range that is near
stoichiometric or fuel-rich of stoichiometric, and can be
adjusted to operate with an exhaust oxygen (02) concentration of
1 percent or less. A lean-burn engine is classified as one with
an A/F operating range that is fuel-lean of stoichiometric, and
cannot be adjusted to operate with an exhaust concentration of
less than l percent. All naturally aspirated, spark-ignition
(SI) four-cycle engines and some turbocharged SI four-cycle
engines are rich-burn engines. All other engines, including all
two-cycle SI engines and all compression-ignition (CD engines
(diesel and dual-fuel), are lean-burn engines.
This chapter presents NOX control techniques by engine type
(i.e., rich-burn or lean-burn) to enable the reader to identify
available NOX control techniques for a particular engine type.
Section 5.1 describes NO,, control techniques for rich-burn
Jv
engines. Lean-burn SI engine NOX control techniques are
presented in Section 5.2. Lean-burn CI engine NOX control
techniques are presented in Section 5.3. Section 5.4 describes
NOX control techniques including exhaust gas return (EGR), engine
derate, water injection, and alternate fuels that are not
considered viable at this time because of marginal NOX reduction
efficiencies and/or lack of commercial availability. References
for Chapter 5 are listed in Section 5.5.
The discussion of each control technique is organized to
include:
1. Process description;
2. Applicability to new and/or existing 1C engines;
3. Factors that affect NOX reduction performance; and
4. Achievable emission levels and test data.
The annual emission reduction based on the achievable
controlled NOX emissions levels is quantified and presented in
Chapter 7 for each control technology.
5.1 NOV CONTROL TECHNIQUES FOR RICH-BURN ENGINES
J\.
Rich-burn engines operate at A/F's near or fuel-rich of
stoichiometric levels, which results in low excess 02 levels and
therefore low exhaust 02 concentrations.' The rich-burn engine
5-2
-------
classification is given in the introduction of this chapter.
Four-cycle, naturally aspirated SI engines and some four-cycle,
turbocharged SI engines are classified as rich-burn engines.
The control technologies available for rich-burn engines
are:
1. Adjustments to A/F;
2. Ignition timing retard;
3. Combination of A/F adjustment and ignition timing
retard;
4. Prestratified charge (PSC®);
5. Nonselective catalytic reduction (NSCR); and
6. Low-emission combustion.
5.1.1 Adjustment of A/F in Rich-Burn Engines
5.1.1.1 Process Description. Rich-burn engines can operate
over a range of A/F's. The A/F can be adjusted to a richer
setting to reduce NOX emissions. As shown in Figure 5-1, small
variations in the A/F for rich-burn engines have a significant
impact on emissions of NOV as well as on those of carbon monoxide
J\.
(CO) and hydrocarbons (HC).1 In the fuel-rich environment at
substoichiometric A/F's, NOX formation is inhibited due to
reduced 02 availability and consequent lower combustion
temperatures. Incomplete combustion in this fuel-rich
environment, however, raises CO and HC emission levels.2
5.1.1.2 Applicability. Adjustment of the A/F can be
performed in the field on all rich-burn engines. For effective
NOX reductions, most engines require that an automatic A/F
feedback controller be installed on the engine to ensure that NOX
reductions are sustained with changes in operating parameters
such as speed, load, and ambient conditions.3 For some
turbocharged engines, A/F adjustments may require that an exhaust
bypass system with a regulator valve be installed to regulate the
airflow delivered by the turbocharger.3 In addition to
maintaining effective emissions control, an automatic A/F
controller also avoids detonation (knock) or lean misfire with
changes in engine operating parameters.
5-3
-------
NATURAL GAS ENGINES
RICH-BURN
2000
I 400H
LEAN-BURN
LOW EMISSION
COMBUSTION
LJJ
14 16 18 20 22 24
A/F RATIO
STOICHIOMETRIC A/F
26
28
30
Figure 5-1.
The effect of air-to-fuel ratio on NOX, CO, and HC
emissions.
5-4
-------
5.1.1.3 Factors that Affect Performance. As shown in
Figure 5-1, A/F adjustment toward fuel-rich operation to reduce
NOX results in rapid increases in CO and, to a lesser extent, HC
emissions. The extent to which the A/F can be adjusted to reduce
NOX emissions may be limited by offsetting increases in CO
emissions. As discussed in Section 5.1.1.2, an automatic A/F
controller may be required to maintain the A/F in the relatively
narrow band that yields acceptable NOX emission levels without
allowing simultaneous CO emission levels to become excessive.
Adjusting the A/F also results in changes in fuel efficiency
and response to load characteristics. Adjusting the A/F to a
richer setting reduces NOX emissions, but increases the
brake-specific fuel consumption (BSFC) while improving the
engine's response to load changes. Conversely, adjusting the A/F
to a leaner setting increases NOX emissions, decreases BSFC, and
decreases the engine's ability to respond to load changes.4'5
5.1.1.4 Achievable Emission Reduction. Table 5-1 shows
estimated emissions for adjusting the A/F for one manufacturer's
rich-burn, medium-speed engines.4 These engines are rated at
2,000 hp or lower. As this table shows, adjusting the A/F ratio
from the leanest to the richest setting can reduce NOX emissions
from an average of 19.2 to 8.0 g/hp-hr. The corresponding
increases in average CO and HC emissions are 1.0 to 33.0 g/hp-hr
and 0.2 to 0.3 g/hp-hr, respectively. As Table 5-1 indicates,
NOX reductions at the richest A/F's are accompanied by
substantial increases in CO emissions of 24 g/hp-hr or more;
increases in HC emissions are relatively minor.
A summary of emission test results from A/F adjustments
performed on seven rich-burn, medium-speed engines is shown in
Table 5-2.6 Controlled NOX emissions ranged from 1.52 to
5.70 g/hp-hr, which represents reductions from uncontrolled
levels ranging from 10 to 72 percent. Emissions of CO and HC
were not reported. The average controlled NOX emission level for
the seven engines was 3.89 g/hp-hr, an average reduction of
45 percent from the average uncontrolled NO., emission level of
Jv
7.22 g/hp-hr. The uncontrolled NOX emissions from these engines
5-5
-------
TABLE 5-1. RANGE OF EMISSIONS RESULTING FROM A/F ADJUSTMENT
FOR ONE MANUFACTURER'S RICH-BURN, MEDIUM-SPEED ENGINES4
Model
series
1
2
3
4
5
6
7
Average
Emissions, g/hp-hr*
Richest A/F
NOX
7.0
10
8.3
8.0
8.5
7.0
7.5
8.0
CO
28
25
34
30.5
35
34
45
33
HCb
0.3
0.3
0.4
0.2
0.4
0.3
0.4
0.3
Leanest A/F
NOX
18
25
20.7
24
20
16
11
19.2
CO
1
0.5
0.8
0.6
1.0
1.0
2.0
1.0
HCb
0.2
0.2
0.3
0.1
0.2
0.3
0.3
0.2
Air-to- fuel, mass basis
Richest A/F
15.5:1
15.5:1
15.5:1
15.5:1
15.5:1
15.5:1
15.15:1
Leanest A/F
17:1
18:1
17.4:1
18:1
17:1
17:1
17:1
aBased on natural gas fuel, hydrogen/carbon ratio of 3.85.
Nonmetbane hydrocarbons only.
5-6
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are considerably lower than the 13 to 27 g/hp-hr range for
uncontrolled NOX emissions shown in Table 4-1 for rich-burn
engines in this range of engine power output. The A/F
corresponding to the uncontrolled and controlled emission levels
was not reported, so the extent to which the A/F was adjusted is
not known. The engines shown in Tables 5-1 and 5-2 are all
medium-speed engines rated at 2,000 hp or less. For low-speed
engines, one manufacturer reports that A/F adjustment for these
rich-burn engines results in potential NOX emission reductions
ranging to 45 percent.7
All available sources indicate that the achievable NOV
Jt
reductions using A/F adjustment are highly variable, even among
identical engine models. Based on the available data, it is
estimated that NOX emissions can be reduced between 10 and
40 percent using A/F adjustment. A reduction of 20 percent is
used to calculate controlled NOX emission levels and cost
effectiveness in Chapter 6.
Adjusting the A/F to a richer setting improves the engine's
response to load changes but results in an increase in BSFC. One
engine manufacturer estimates the increase in BSFC to be 1 to
5 percent.7
5.1.2 Adjustment of Ignition Timing in Rich-Burn Engines
5.1.2.1 Process Description. Adjusting the ignition timing
in the power cycle affects the operating pressures and
temperatures in the combustion chamber. Advancing the timing so
that ignition occurs earlier in the power cycle results in peak
combustion when the piston is near the top of the cylinder, when
the combustion chamber volume is at a minimum. This timing
adjustment results in maximum pressures and temperatures and has
the potential to increase NOX emissions. Conversely, retarding
the ignition timing causes the combustion process to occur later
in the power stroke when the piston is in its downward motion and
combustion chamber volume is increasing. Ignition timing retard
5-8
-------
reduces operating pressures, temperatures, and residence time and
has the potential to reduce NOX formation.
5.1.2.2 Applicability. Adjustment of the ignition timing
can be performed in the field on all rich-burn engines.
Sustained NOX reduction and satisfactory engine operation,
however, typically require replacement of the ignition system
with an electronic ignition control system.** The electronic
control system automatically adjusts the ignition timing to
maintain satisfactory engine performance with changes in
operating parameters and ambient conditions.
5.1.2.3 Factors That Affect Performance. Adjustment to
retard the ignition timing from the standard setting may reduce
NOX emissions, but it also affects other engine parameters.
Shifting the combustion process 'to later in the power cycle
increases the engine exhaust temperature, which may affect
turbocharger speed (if the engine is so equipped) and may have
detrimental effects on the engine exhaust valves. Brake-specific
fuel consumption also increases, as does the potential for
misfire. Engine speed stability, power output, and response to
load changes may also be adversely affected. These effects on
engine parameters occur continuously and proportionately with
increases in timing retard and generally limit ignition retard to
4° to 6° from the standard setting.9
5.1.2.4 Achievable Emission Reduction. Ignition timing can
typically be adjusted in a range of up to approximately 4° to 6°
from the standard timing setting to reduce NOX emissions. The
extent of ignition retard required to achieve a given NOX
reduction differs for each engine model and operating speed. For
example, 2° to 4° of retard is likely to achieve a greater NOX
reduction on an engine with an operating speed of 500 to
1,000 rpm than an engine with an operating speed of 2,000 to
3,000 rpm.^ Data to quantify the effect of ignition retard on
rich-burn engines were available from three engine manufacturers.
The first manufacturer indicates that, in general, NO., emission
J^
reductions of up to 10 percent can be achieved by retarding
ignition timing.7 The second manufacturer provided emission data
5-9
-------
for an engine operated at three ignition timing settings.9 These
data, plotted in Figure 5-2, suggest that the NOX reduction
achieved by ignition retard in rich-burn engines largely depends
upon the A/F. For operation near and rich of stoichiometric,
timing retard has only a small effect on NOX levels. According
to the manufacturer, this minimal effect is thought to be because
the lack of oxygen and lower temperatures in this A/F range
substantially mitigate the effect of any further peak temperature
and pressure reduction achieved by retarding the ignition timing.
For above-stoichiometric A/F's, ignition retard reduces NOX
emissions, but Figure 5-2 shows that these reductions are
realized only at near-peak NOX emission levels. A third
manufacturer provided data, presented in Figure 5-3, for a
rich-burn engine that indicates potential NOX reductions for a 5.°
retard ranging from 10 to 40 percent, depending upon the A/F.10
Unlike the plot shown in Figure 5-2, potential NOX reductions
increase at richer A/F's.
The available data suggest that the effect of ignition
timing on NOX reduction is engine-specific, and also depends on
the A/F. The achievable NO,, reduction ranges from essentially no
Jt
reduction to as high was 40 percent, depending on the engine
model and the A/F. A reduction of 20 percent is used to
calculate controlled NOX emission levels and cost effectiveness
in Chapter 6.
Timing retard greater than approximately 4° to 6° results in
marginal incremental NOX reduction and negative engine
performance as described in Section 5.1.2.3. The increase in
BSFC corresponding to increases in timing retard was estimated by
one manufacturer to range up to approximately 7 percent.7
Emissions of CO and HC are largely insensitive to changes in
ignition timing.5'10 The higher exhaust temperatures resulting
from ignition retard tend to oxidize any unburned fuel or CO,
offsetting the effects of reduced combustion chamber residence
time.
5-10
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5-12
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5.1.3 Combination of A/F Adjustment and Ignition Timing Retard
Either A/F adjustment or ignition timing retard can be used
independently to reduce NOX emissions from rich-burn engines.
These control techniques can also be applied in combination.
Automated controls for both A/F and ignition timing are required
for sustained NOX reductions with changes in engine operating
conditions. As is the case with either control technique used
independently, potential NOX reductions for the combination of
control techniques are engine-specific. As previously shown for
one manufacturer's engines in Figure 5-2, A/F adjustment to a
richer setting achieves the greatest NO., reductions, and at these
Jv
sub-stoichiometric A/F's, ignition timing retard achieves little
or no further NOX reduction. A manufacturer of low-speed engines
also reports that the range of achievable NOX reductions is the
same for the combination of A/F adjustment and ignition timing
fj
retard as for A/F adjustment alone.' The data presented in
Figure 5-3 also support this conclusion. The minimum controlled
NOX emission level using A/F adjustment is not further reduced
with a 5° ignition timing retard from the 30° setting.
Figure 5-3, however, does show that the combination of A/F
and timing retard offers some flexibility in achieving NO..
Jv
reductions. For example, a controlled NO^ emission level of
Jv
400 ppmv (5.3 g/hp-hr) represents a NOX reduction of over
50 percent from maximum emission levels for the engine shown in
Figure 5-3. While Figure 5-3 shows that this controlled NO..
Jv
emission level can be achieved by A/F adjustment alone, using a
5° ignition timing retard in combination with A/F adjustment
achieves the 400 ppmv controlled NOX level at a higher (leaner)
A/F. Since parametric adjustments affect such operating
characteristics as fuel consumption, response to load changes,
and other emissions, the combination of parametric adjustments
offers the potential to reduce NOX emissions while minimizing the
impact on other operating parameters. In particular, CO
emissions rise sharply as the A/F is reduced but are largely
insensitive to ignition timing retard. Using timing retard in
combination with A/F adjustment may allow the engine to achieve a
5-13
-------
given NOX reduction at a higher A/F, thereby minimizing the
increase in CO emissions.
Based on the available data, it is expected that NOX
reductions of 10 to 40 percent can be achieved using a
combination of A/F adjustment and ignition timing retard. While
this is the same range expected for A/F adjustment alone, the
combination of control techniques offers the potential in some
engines to achieve NOX reductions at the upper end of this range
with reduced impacts on CO emissions or other operating
characteristics. A reduction of 30 percent is used to calculate
controlled NOX emission levels and cost effectiveness in
Chapter 6.
5.1.4 Prestratified Charge (PSC®)
5.1.4.1 Process Description. Prestratified charge injects
air into the intake manifold in a layered, or stratified, charge
arrangement. As shown in Figure 5-4, the resulting
stratification of the air/fuel mixture remains relatively intact
when drawn into the combustion chamber and provides a readily
ignitable mixture in the vicinity of the spark plug while
maintaining an overall fuel-lean mixture in the combustion
chamber.11 This stratified charge allows a leaner A/F to be
burned without increasing the possibility of misfire due to lean
flammability limits. This leaner combustion charge results in
lower combustion temperatures, which in turn lower NOX
formation.12
A PSC* kit consists of new intake manifolds, air hoses, air
filters, control valve(s), and either a direct mechanical linkage
to the carburetor or a microprocessor-based control system.11 A
typical PSC* system schematic is shown in Figure 5-5.
5.1.4.2 Applicability. The PSC® system is available as an
add-on control device for rich-burn, naturally aspirated or
turbocharged, carbureted, four-cycle engines. These engines
represent approximately 20 to 30 percent of all natural gas-fired
engines and 30 to 40 percent of natural gas-fired engines over
300 hp.13 Fuel-injected engines and blower-scavenged engines
cannot use PSC®. Kits are available on an off-the-shelf basis to
5-14
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retrofit virtually all candidate engines with a rated power
output of 100 hp (75 JcW) or higher, regardless of the age of the
engine.14 Experience with PSC® systems to date has been
primarily those engines operating at a steady power output and
ranging in size up to approximately 2,000 hp. A limited number
of PSC® systems have been used in cyclical load applications.14
Prestratif ied charge systems have been successfully applied
to engines fueled with natural gas as well as to engines using
sulfur- bearing fuels such as digester gas and landfill
5.1.4.3 Factors That Affect Performance. The NOX reduction
efficiency for PSC® is determined by the extent to which the air
content of the stratified charge can be increased without
excessively affecting other operating parameters. These
parameters are engine power derate, increased CO emissions, and
to a lesser extent, HC emissions. The effects on engine power
output and CO and HC emissions are quantified in Section 5.1.4.4.
5.1.4.4 Achievable NOX Emissions Levels Using PSC® . The
achievable NOX emission reductions using PSC® are limited by the
quantity of air that can be induced by the intake manifold
vacuum, the acceptable level of engine power derate, and the
acceptable increase in the level of CO emissions.
Information provided by the vendor for PSC® states that the
achievable controlled emission levels for natural gas -fueled
engines equipped with PSC® are:14
Emissions
NOV
CO
NMHC
g/hp-hr
2
3
<2
ppmv @ 15% 0,a
146
360
<425
aConversion factors from g/hp-hr to ppmv at 15 percent 02 are
from Section 4.3 for lean-burn engines. Lean-burn conversion
factors are used because PSC® typically raises the exhaust 02
levels above 4 percent.
Emission data from several sources suggest that controlled
NOX emission levels for PSC® can meet the levels shown above and,
5-17
-------
where necessary, can achieve even lower levels. South Coast Air
Quality Management District (SCAQMD) Rule 1110.2 requires that
engines equipped with PSC® achieve an 80 percent NOX reduction at
90 percent of rated load. A total of 11 test reports were
available for SCAQMD installations, and are presented in
Table 5-3.15"23 All of these installations achieved NOX
reductions of 79 percent or higher. Emission levels were
reported only in units of ppmv; units of g/hp-hr were calculated
using the correction factors from Section 4.3. Controlled NO,.
J^
emission levels range from 83 to 351 ppmv (l.l to 4.8 g/hp-hr).
In all but one case CO emissions increased as a result of PSC®,
ranging from 137 to 231 ppmv (1.1 to 1.9 g/hp-hr), an increase of
25 to 171 percent over uncontrolled CO levels. Hydrocarbon
emissions were not reported.
An emission data base was provided by the Ventura County Air
Pollution Control District (VCAPCD),24 Engines operating with
PSC® in VCAPCD must achieve a NOX emission level of 50 ppmv
(0.75 g/hp-hr), or a 90 percent NOX reduction, in accordance with
Rule 74.9. Emission data for a total of 79 emission tests,
performed at 16 engine installations, are presented in Table A-l
in Appendix A. Table A-l shows that 68 of these emission tests
report NOX levels consistent with the VCAPCD requirements. The
data base provided incomplete information to confirm compliance
for the 11 remaining tests. In all cases, however, the
controlled NOX emission levels were less than 100 ppmv
(1.4 g/hp-hr), and in some cases were 25 ppmv (0.35 g/hp-hr) or
less. Of the 79 test summaries, all but 5 reported controlled CO
emissions below 300 ppmv (2.5 g/hp-hr), and all but 6 reported
controlled NMHC emission levels below 100 ppmv (0.5 g/hp-hr).
Uncontrolled CO and NMHC emission levels prior to installation of
the PSC® system were not reported, so no assessment of the
increases in these emissions as a result of PSC* could be made
for these installations.
In general, CO and HC emission levels increase as NOX
emission levels are reduced using PSC®.12 The increase is due to
incomplete combustion that occurs in the larger quench zone
5-18
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associated with PSC* near the combustion chamber walls and the
lower exhaust temperatures resulting from the leaner A/F's. The
extent to which these emission levels increase, however, is
highly variable for various engine models and even among engines
of the same model, as shown in Tables 5-3 and A-l.
For fuels with relatively high levels of C02, such as
digester gas and landfill gas, the impact of PSC* on CO emissions
is a minimal increase or in some cases a decrease in CO
emissions. Controlled CO emission levels using PSC* for
high-C02-content fuels typically range from 200 to 500 ppmv (1.67
to 4.17 g/hp-hr). Test reports for PSC* operation on two
digester gas-fired units show CO levels ranging from 140 to
278 ppmv, corrected to 15 percent 02 (1.17 to 2.32 g/hp-hr).12
Using PSC® to reduce NOX emissions typically results in a
reduction in the rated power output of the engine. According to
the vendor, the power derate for PSC* ranges from 15 to
20 percent for naturally aspirated engines and from zero to
5 percent for turbocharged engines. The controlled NOX level of
2 g/hp-hr (150 ppm) at rated load can be further reduced as low
as 1.0 to 1.2 g/hp-hr (73 to 88 ppmv), but engine power output
derate increases to 25 percent for naturally aspirated engines
and to 10 percent for turbocharged engines.14 This engine derate
results from displacing with air a portion of the carburetor-
delivered combustion charge in the intake manifold; the resulting
leaner combustion charge yields a lower power output. Where the
design of an existing naturally aspirated engine will accommodate
the addition of a turbocharger, or an existing turbocharger can
be replaced with a larger unit, these equipment changes can be
included with the PSC® retrofit kit and the power derate can be
reduced to 5 to 10 percent.14 This type of installation is
similar to the altitude kits installed on integral engines
(engines with both power cylinders and gas compression cylinders)
to develop full sea level ratings at higher elevations. The
horsepower loading on the engine frame is limited when adding a
turbocharger so as not to exceed the original naturally aspirated
engine rating.
5-20
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The power derate associated with PSC® applies only to the
rated power output at a given installation. For applications
where an engine operates below rated power output, no power
deration occurs. For example, if a naturally aspirated engine
with a rated power output of 100 hp is used in an application
that requires 80 hp or less, no power deration will result from
the installation of a PSC® system.14
The emission test summaries shown in Tables 5-3 and A-l do
not include power output data to assess the power derate
associated with the emission levels shown. Data were available,
however, for a limited number of installations that correlate
power output with controlled NOX emission levels. These
installations are summarized in Table 5-4. 5 In all cases the
controlled NO., levels are less than 2 g/hp-hr (150 ppmv) . The
Jv
percent power derate was determined by the PSC® supplier by
comparing the calculated power output at the time of testing with
the manufacturer's published power rating, which was adjusted for
site elevation and fuel composition. Engine No. 5 is a naturally
aspirated engine, and the PSC® installation did not include the
addition of a turbocharger. For this engine, the power derate
for a total of four tests averages 12 percent. The power derate
is also 12 percent (averaged for three tests) for engine No. 8, a
turbocharged engine for which the PSC® installation included no
modifications to the turbocharger. For turbocharged engines for
which the PSC® installation included modification or replacement
of the turbocharger to increase the turbo boost (engine Nos. 1,
2, 6, and 7), the power derate ranges from 0 to 32 percent. The
32 percent figure corresponds to an engine tested while process
capacity demand was low, and the engine operated below the
maximum available power output. As a result, the 32 percent
figure overstates the required derate to some extent. Excluding
this case, the power and rate for the turbocharged engines with
turbocharger modifications ranges from 0 to 5 percent. These
power derates are consistent with those stated by the PSC® vendor
for controlled NOX emission levels of 2 g/hp-hr.
5-21
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It is important to note that the power derate associated
with PSC® depends on site-specific conditions, including the
controlled NOX emission level, engine model, and operating
parameters. Several sources have indicated that the power derate
associated with PSC® may be greater in some cases than the levels
presented in this section. A determination of the power derate
associated with a potential PSC® installation should be made on a
case-by-case basis.
Based on the available data presented in this section, it is
estimated that a controlled NOX emission level of 2.0 g/hp-hr
(150 ppmv) or less is achievable in rich-burn engines using PSC®,
and this 2.0 g/hp-hr figure is used in Chapter 6 to calculate
controlled NOX emission levels and cost effectiveness.
Moderate NOX reductions to approximately 4 to 7 g/hp-hr
reduce BSFC by approximately 5 to 7 percent. Further NOX
reductions below the 4 to 7 g/hp-hr level, however, increase BSFC
by as much as 2 percent over uncontrolled levels.14
5.1.5 Nonselective Catalytic Reduction
5.1.5.1 Process Description. Nonselective catalytic
reduction is achieved by placing a catalyst in the exhaust stream
of the engine. This control technique is essentially the same as
the catalytic reduction systems that are used in automobile
applications and is often referred to as a three-way catalyst
because it simultaneously reduces NOX, CO, and HC to water, C02,
and N2. This conversion occurs in two discrete and sequential
steps, shown in simplified form by the following equations:26
Step l Reactions: 2CO + 02 -» 2C02
2H2 + 02 -* 2H20
HC + 02 -* C02 + H20
Step 2 Reactions: NOX + CO -> C02 + N2
NOX + H2 -* H20 + N2
NOX + HC -» C02 + H20 + N2
The Step 1 reactions remove excess oxygen from the exhaust
gas because CO and HC will more readily react with 02 than with
NOX. For this reason the O2 content of the exhaust must be kept
5-23
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below approximately 0.5 percent to ensure adequate NOX reduction.
Therefore, NSCR is applicable only to rich-burn engines.
A schematic for a typical NSCR system is shown in
Figure 5-6. An 02 sensor is placed in the exhaust, and the A/F
is adjusted in the fuel-rich direction from stoichiometric as
necessary to maintain suitable exhaust 02 and CO levels for
adequate NOX reduction through the catalyst reactor. Manual and
automatic A/F controllers are available. With a manual A/F
control system, the signal from the exhaust O2 sensor is
typically connected to a bank of status lights. When indicated
by these status lights, the operator must manually adjust the A/F
to return the 02 content of the exhaust to its proper range.
With an automatic A/F control system, the exhaust 02 sensor is
connected to a control system that uses this signal to
automatically position an actuator installed on the engine
carburetor so the exhaust 02 concentration is maintained at the
proper level.27
One manufacturer uses natural gas as the reducing agent in
the NSCR system to reduce NOX. The natural gas is injected into
the exhaust stream ahead of the catalyst reactor and acts as a
reducing agent for NOX in the low (<2 percent) 02 environment.28
A second proprietary NSCR system that injects natural gas into
the exhaust stream uses an afterburner downstream of the engine
and two catalyst reactors. A schematic of this system is shown
in Figure 5-7. This system injects natural gas into the
afterburner to achieve a 925°C (1700°F) minimum exhaust
temperature to maximize destruction of unburned HC. The exhaust
is then cooled in the first heat exchanger to approximately 425°C
(800°F) prior to entering the reduction catalyst, where CO and
NO., are reduced. Excess CO emissions exiting the reduction
J^
catalyst are maintained at approximately 1,000 ppmv to minimize
ammonia and cyanide formation. A second heat exchanger further
cools the exhaust to approximately 230°C (450°F) prior to
entering the oxidation catalyst to minimize the reformation of
NOX across the oxidation catalyst. The oxidation catalyst is
used to reduce CO emissions.29 According to the vendor, this
5-24
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catalytic system can also be used with lean-burn SI and CI
engines in lieu of SCR.
5.1.5.2 Applicability for NSCR. Nonselective catalytic
reduction applies to all carbureted rich-burn engines. The
limitation to carbureted engines results from the inability to
install a suitable A/F controller on fuel-injected units. This
control technique can be installed on new engines or retrofit to
existing units. For vintage engines, after-market carburetors
are available to replace primitive carburetors, where necessary,
to achieve the necessary A/F control for NSCR operation.26
Another factor that limits the applicability of NSCR is the
type of fuel used. Landfill and digester gas fuels may contain
masking or poisoning agents, as described in Section 5.1.5.3,
that can chemically alter the active catalyst material and render
the catalyst ineffective in reducing NOX emissions. One catalyst
vendor cited NSCR experience in landfill gas-fueled applications
where the fuel gas is treated to remove contaminants.30
There is limited experience with NSCR applications on
cyclically loaded engines. Changes in engine load cause
variations in the exhaust gas temperature as well as NOX and 02
exhaust concentrations. An A/F controller is not commercially
available to maintain the exhaust 02 level within the narrow
range required for consistent NOX reduction for cyclically loaded
engines such as those used to power rod pumps.2 One vendor
offers an NSCR system that uses an oversized exhaust piping
system and incorporates the catalyst into the muffler design.
The increased volume of this exhaust system acts to increase the
residence time in the catalyst, which compensates for the adverse
impacts of other operating parameters. This vendor has installed
this catalyst/muffler NSCR system in both base-load and cyclical-
load applications.31
5.1.5.3 Factors That Affect Performance. The primary
factors that affect the performance of NSCR are control of the
engine A/F, the exhaust temperature, and masking or poisoning
agents in the exhaust stream. To achieve the desired chemical
reactions to reduce NOX emissions (see Section 5.1.4.1) and
5-27
-------
minimize CO emissions from the catalyst, the exhaust 02
concentration must be maintained at approximately 0.5 percent by
volume. This O2 level is accomplished by maintaining the A/F in
a narrow band, between 16.95 and 17.05 according to one catalyst
vendor.27' 18 An automatic A/F controller offers the most
effective control of NOX and CO emissions since it continually
monitors the 02 exhaust content and can maintain the A/F in a
narrow range over the entire range of operating and ambient
conditions.
The operating temperature range for various NSCR catalysts
is from approximately 375° to 825°C (700° to 1500°F ). For NOX
reductions of 90 percent or greater, the temperature window
narrows to approximately 425° to 650°C (800° to 1200°F). This
temperature window coincides with the normal exhaust temperatures
for rich-burn engines.1^ This temperature range is a compilation
of all available catalyst formulations. Individual catalyst
formulations will have a narrower operating temperature range,
and maximum reduction efficiencies may not be achievable over the
entire spectrum of exhaust temperatures for an engine operating
in a variable load application. Abnormal operating conditions
such as backfiring can result in excessive temperatures that
damage the highly porous catalyst surface, permanently reducing
the emission reduction capability of the catalyst.
Masking or poisoning of the catalyst occurs when materials
deposit on the catalyst surface and either cover the active areas
(mask) or chemically react with the active areas and reduce the
catalyst's reduction capacity (poison). Masking agents include
sulfur, calcium, fine silica particles, and hydrocarbons.
Poisoning agents include phosphorus, lead, and chlorides. These
masking and poisoning agents are found in the fuel and/or
lubricating oils. The effects of masking can be reversed by
cleaning the catalyst (except for fine silica particles that
cannot be dislodged from the porous catalyst surface); the
effects of poisoning are permanent and cannot be reversed. '
5.1.5.4 Achievable Emission Reductions Using NSCR.
Information provided for the proprietary NSCR system that uses
5-28
-------
both a reducing catalyst and an oxidation catalyst states
controlled NOX emission levels of less than 25 ppmv
(0.37 g/hp-hr) are achievable. Corresponding CO emissions are
expected to be less than 100 ppmv.29 No test data were available
for this system design.
For NSCR systems that use a single catalyst reactor, the
ratio of CO to NOX entering the catalyst unit in a properly tuned
system is approximately 2:1. According to one NSCR vendor, the
A/F is adjusted to achieve an approximate CO level of 6,000 ppmv
and a NOY level of 3,000 ppmv entering the catalyst. At these
Jt
emission levels, the typical controlled emissions levels exiting
the catalyst are:27
Emissions
NOY
CO
HC
g/hp-hr
2
2
0.5
Approximate
ppmv at
15 percent 0-?a
134
220
97
aConversion factors from g/hp-hr to ppmv at
15 percent 02 are from Section 4.3 for rich-
burn engines.
Compliance requirements in several local regulatory
districts in California require considerably lower NOX emission
levels than those shown above. The SCAQMD Rule 1110.2 requires
an 80 percent N0_- reduction, with a maximum CO emission limit of
Jt
2,000 ppmv. Four test summaries of SCAQMD engine installations
using NSCR are presented below:^2
Test No.
1
2
3
4
NOX reduction
(percent)
92
99
99
82
CO emissions
(ppmv)
118
258
364
1,803
5-29
-------
Actual NOX ppmv levels were not included in the available test
summary. These data suggest that CO emission levels do not
necessarily increase with increased NOX reduction. No HC
emission levels were reported.
The VCAPCD emission data base includes over 250 emission
test summaries from 49 engine installations operating in
continuous-duty applications.24 These emission summaries are
shown in Table A-2 in Appendix A. Of the approximately
275 tests, only 2 did not achieve compliance with the VCAPCD
Rule 74.9 NOX requirement of 50 ppmv or 90 percent reduction.
One additional test summary showed a NOX emission level higher
than 50 ppmv, but no reduction figure was listed. Every test
achieved a NOX emission level of less than 100 ppmv
(1.5 g/hp-hr). Levels of CO emissions vary greatly, ranging from
less than 100 to over 19,000 ppmv (0.9 to 173 g/hp-hr). Prior to
1989, there was no CO emission limit in VCAPCD; in 1989, a limit
of 4,500 ppmv was added to VCAPCD Rule 74.9. Evaluation of the
275 continuous-duty installations shows the following average
annual emission levels:
Year(s)
86-88
89
90-92
Controlled emission averages (ppmv)
NOY
26.9
18.5
22.7
CO
4691
6404
2424
NMHC
27.5
39.0
73.6
These data indicate that controlled CO emission levels decreased
between 48 and 62 percent following implementation of the CO
emission limit, with little or no effect on controlled NOX
emission levels. The data base included only a limited number of
NMHC emission levels, which range from I to 694 ppmv (0 to
3.3 g/hp-hr).
These emission averages and the emission levels presented in
Table A-2 suggest that controlled CO and NMHC emission levels
vary widely for NSCR applications and are not necessarily
5-30
-------
inversely proportional to controlled NOX emission levels. An
oxidation catalyst can be installed downstream of the NSCR
catalyst, where necessary, to further reduce CO emissions. Air
injection would be required upstream of the oxidation catalyst to
introduce 02 into exhaust stream.
The VCAPCD emission data base shows NSCR installations that
have been in operation for 5 years or longer. The maintenance
requirements and the catalyst replacement schedules were not
available. Catalyst vendors will guarantee NOX reduction
efficiencies as high as 98 percent and typically guarantee
catalyst life and system performance for 2 or 3 years.33
Precious metal catalysts are used in NSCR systems, so the spent
catalyst does not contain potentially hazardous materials. Most
catalyst vendors offer a credit toward the purchase of new
catalyst for return of these spent catalysts.33
Based on the data presented in this section, it is estimated
that a NOX reduction of 90 percent or higher is achievable using
NSCR with rich-burn engines. A 90 percent reduction is used in
Chapter 6 to calculate controlled NOX emission levels and cost
effectiveness.
The fuel-rich A/F setting and the increased back pressure on
the engine caused by the catalyst reactor may reduce power output
and increase the BSFC. The back pressure created by an NSCR
system was not provided, but the estimate for an SCR system is 2
to 4 inches of water (in. w.c.).4 For a 4-in. back pressure,
one engine manufacturer estimated a power loss of 1 percent for
naturally aspirated engines and 2 percent for turbocharged
engines. The increase in BSFC was estimated at 0.5 percent for
either naturally aspirated or turbocharged engines.3 As stated
in Section 5.1.1.1, rich-burn engines can be operated over a
range of A/F's, so the incremental change between the A/F setting
required for NSCR and the A/F used prior to installation of the
NSCR is also site-specific. The increase in BSFC estimated by
NSCR vendors ranged from 0 to 5 percent. Another source provided
information showing that the BSFC increase could potentially be
greater than 10 percent for some engines.3^
5-31
-------
5.1.6 Low-Emission Combustion
5.1.6.1 Process Description. Rich-burn engines operate at
near-stoichiometric A/F's. As shown in Figure 5-1, NOX emissions
can be greatly reduced by increasing the A/F so that the engine
operates at very lean A/F's, as depicted in the region at the
right side of this figure where NOX formation is low. Extensive
retrofit of the engine and ancillary systems is required to
operate at the higher A/F's. These low-emission combustion
designs are also referred to as torch ignition, jet cell, and
CleanBurn® by various manufacturers. (CleanBurn* is a registered
trademark of Cooper Industries.)
The increased air requirements for low-emission engines can
range up to nearly twice the levels required for rich-burn
operation according to information provided by one engine
manufacturer.1 This increased airflow is provided by adding a
turbocharger and intercooler or aftercooler to naturally
aspirated engines or by replacing an existing turbocharger and
inter/aftercooler with a larger-capacity unit. The air intake
and filtration system, carburetor(s), and exhaust system must
also be replaced to accommodate the increased flows.
The very lean mixture also requires substantial modification
of the combustion chamber to ensure ignition and stable
combustion. For engines that have a relatively small cylinder
bore, the combustion chamber can use an open cylinder design,
which is similar to a conventional combustion chamber but
incorporates improved swirl patterns to promote thorough mixing.
Larger cylinder bores cannot reliably ignite and sustain
combustion with an open-cylinder design and a precombustion
chamber (PCC) is used. These low-emission combustion designs
vary somewhat with each manufacturer, but representative sketches
are shown in Figure 5-8.1 One manufacturer's low-emission
combustion chamber with a PCC design is shown in Figure 5-9.36
The PCC is an antechamber that has a volume of 5 to 10 percent of
the main chamber and ignites a fuel-rich mixture, which
propagates into the main cylinder and ignites the very lean
combustion charge.11 The high exit velocity of the combustion
5-32
-------
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5-33
-------
PRECHAMBER FUEL GAS
SPARK PLUG
MIXING VANE
-•-AIR
MAIN GAS
SUPPLY
CHECK VALVE
MAIN
GAS
VALVE
MAIN COMBUSTION CHAMBER
Figure 5-9.
Low-emission engine combustion chamber with
a precombustion chamber.^°
5-34
-------
products from the PCC has a torch-like effect in the main chamber
and results in improved mixing and combustion characteristics.
As a result, leaner A/F's can be used in a main combustion
chamber with a PCC design, and NOX emissions are lower than those
from open-chamber designs. Redesigning the combustion chamber in
the case of either an open or a PCC design usually requires
replacing the intake manifolds, cylinder heads, pistons, and the
ignition system.
5.1.6.2 Applicability of Low-Emission Combustion. The
applicability of combustion modifications to rich-burn engines is
limited only by the availability of a conversion kit from the
manufacturer and application considerations. Since the
low-emission conversion essentially requires a rebuild of the
engine, the hardware must be available from the engine
manufacturer. Responses received from engine manufacturers show
that the availability of retrofit kits varies by manufacturer,
from only a few models to virtually all models.37"42
When considering a low-emission conversion for a rich-burn
engine, the duty cycle of the engine must be taken into
consideration. Conversion to a low-emission design may adversely
affect an engine's response to load characteristics. According
to one manufacturer, a low-emission engine can accept a load
increase up to 50 percent of rated load and requires
approximately 15 seconds to recover to rated speed. A
turbocharged rich-burn engine is limited to this same 50 percent
load increase but will recover to rated speed in 7 seconds. A
naturally aspirated rich-burn engine can accept a load of up to
100 percent of rated load and will stabilize at rated speed in
3.5 seconds.43 Applications that have substantial load swings,
such as power generation applications that are not tied to the
utility grid or cyclically loaded engines, may not be able to use
a low-emission design due to reduced load acceptance capability.
An additional consideration is that the fuel delivery
pressure requirement may be higher for a low-emission engine due
to the addition of the turbocharger. This higher fuel pressure
5-35
-------
requirement may require the addition of a fuel gas booster
compressor.
5.1.6.3 Factors That Affect Performance. The factors that
most affect the emission reduction performance of a rich-burn
engine that has been converted to low-emission combustion are the
design of the new combustion chamber and the volume of air that
can be delivered. The new combustion chamber design determines
the highest A/F that can be used, and as shown in Figure 5-1,
higher A/F's will result in lower NOX emissions. In general,
lower NOX emissions can be achieved using a PCC than with an open
chamber design because of the leaner A/F's that can be reliably
combusted in the main combustion chamber with a PCC design.
The turbocharger necessary to supply the additional intake
air for clean-burn operation results in increased working
pressures in the engine. Existing rich-burn engine designs may
limit the turbocharger size that can be retrofit due to either
strength limitations of the existing engine frame or space
constraints of the existing air intake configuration. Any
limitation in the availability of combustion air may effectively
limit the operating A/F below optimum levels and therefore limit
potential NOX reductions.
5.1.6.4 Achievable Emission Levels Using Low-Emission
Combustion. The nominal emission levels provided by engine
manufacturers for low-emission open chamber designs are:37"42
1 Emissions, g/hp-hr
NOY
3.8-11.7
CO
0.9-3.6
HC
1.0-4.6
Emissions, ppmv at 15% 07
NOY
280-865
CO
110-440
HC
250-990
The nominal emission levels provided by engine manufacturers
for PCC designs are:37"42
Emissions, g/hp-hr
NOY
1.5-2.5
CO
1.3-3.5
HC
0.6-4.9
Emissions, ppmv at 15% 07
NOY
110-185
CO
160-425
HC
130-1,055
5-36
-------
As can be seen from the above tables, NOX emissions are
substantially lower for engines that use a PCC design. Since an
open chamber design is generally used in smaller, high-speed
engines, these engines typically emit higher controlled NOX
emissions than do larger, low-speed engines. These figures show
that the levels of CO and HC, however, are not substantially
influenced by the combustion chamber geometry.
Reductions in NOX emissions using combustion modifications
generally result in higher CO and HC emission levels. For this
reason, it is not likely that the low end of each range for NO..,
Jv
CO, and HC in the figure listed above can be achieved
simultaneously.
The percent reduction that is achievable by converting a
rich-burn engine to a low-emission design can be misleading
because the uncontrolled emission levels can vary widely with
slight adjustments in the A/F, as shown in Figure 5-1. For
example, average NOX emission levels from rich-burn engines can
range from 8.0 to 19.2 g/hp-hr with adjustments to the A/F (see
Table 5-1). Conversion to low-emission combustion can achieve
controlled NOX emission levels of 1.5 to 2.5 g/hp-hr. The
percent reduction could therefore range from 69 to 92 percent,
depending upon the uncontrolled and controlled NO., levels used to
./(.
calculate the percent reduction.
Test results for five engines that were converted from rich-
burn to low-emission combustion are presented in Table 5-5.6'44
This table shows that controlled NOX emissions range from 0.37 to
2.0 g/hp-hr (29 to 146 ppmv at 15 percent 02) and average
1.02 g/hp-hr (75.6 ppmv at 15 percent 02). Carbon monoxide
emissions range from 1.6 to 2.6 g/hp-hr (192 to 323 ppmv at
15 percent 02) and average 2.19 g/hp-hr (265 .ppmv at 15 percent
02)• Levels of HC emissions range from 0.26 to 0.6 g/hp-hr (55
to 127 ppmv at 15 percent 02) and average 0.39 g/hp-hr (83.7 ppmv
at 15 percent 02). These engines all use a PCC design. The NOX
emissions are lower than those provided by engine manufacturers,
but CO and HC emissions fall within the ranges provided by the
manufacturers.
5-37
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Table 5-6 presents achievable emissions levels for new
low-emission engines that were developed by engine manufacturers
from rich-burn designs.6 For a total of eight engines NOX
emissions range from 0.73 to 2.00 g/hp-hr (55 to 150 ppmv at
15 percent 02) and average 1.50 g/hp-hr (112 ppmv at 15 percent
02) . Emission levels for CO range from 1.20 to 3.10 g/hp-hr (144
to 372 ppmv at 15 percent 02) and average 2.19 g/hp-hr (263 ppmv
at 15 percent 02). Hydrocarbon emissions range from 0.13 to
2.20 g/hp-hr (28 to 466 ppmv at 15 percent 02) and average
0.95 g/hp-hr (200 ppmv at 15 percent O2). These emission levels
all fall within the ranges quoted by the manufacturers.
Test data for low-emission engines developed from rich-burn
engine designs were also available from the VCAPCD data base.24
These data are presented in Table A-3 in Appendix A, and include.
a total of 124 emission tests performed on 15 engines,
representing 4 engine models from 2 manufacturers. Controlled
NO., emission limits for these engines in VCAPCD are 125 ppmv or
Jv.
80 percent NOX reduction. Controlled CO and NMHC emission limits
are 4500 and 750 ppmv, respectively. The data base indicates
that all engines met these compliance limits. Controlled NOX
emission levels in Table A-3 range from 11 to 173 ppmv (0.15 to
2.3 g/hp-hr). Corresponding CO emission levels vary widely, from
3 to 3,327 ppmv (0 to 27 g/hp-hr). The range for NMHC emissions
is 74 to 364 ppmv (0.4 to 1.7 g/hp-hr). To some extent, the data
show an inverse relationship between NOX and CO emissions, as the
three highest CO emission levels correspond to NOX emission
levels of 35 ppmv or less, and the highest NMHC emission level
corresponds to the lowest NOX emission level (11 ppmv). This
relationship does not hold true for all cases, however, as many
of the emission tests show relatively low controlled levels for
all three emissions. The data also show that controlled emission
levels are sustained over time, as compliance limits have been
maintained at all installations, dating back to when the data
base was developed in 1986.
No information was available to determine whether the
low-emission engines in Table A-3 were purchased as new equipment
5-39
-------
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5-40
-------
or were retrofit from existing rich-burn engines. Based on the
information provided by engine manufacturers and the data
presented in Tables 5-5, 5-6, and A-3, it is estimated that a
controlled NOX emission level of 1.0 to 2.0 g/hp-hr is achievable
for rich-burn engines that have been converted to low-emission
combustion. A 2.0 g/hp-hr figure is used in Chapter 6 to
calculate controlled NOX emission levels and cost effectiveness.
The operating characteristics of low-emission designs,
including substantially leaner A/F and increased operating
pressures from turbocharging, suggest improved fuel economy.
Information provided by engine manufacturers shows that, in
general, engine heat rates range from no change to improved fuel
efficiency as high as 21 percent. For a few engines, however,
the fuel efficiency actually declined as much as 2 percent.37"42.
5.2 NOV CONTROL TECHNIQUES FOR LEAN-BURN SI ENGINES
Jv
As discussed at the beginning of this chapter, a lean-burn
engine is classified as one with an A/F operating range that is
lean of stoichiometric and cannot be adjusted to operate with an
exhaust 02 concentration of less than one percent. For SI
engines, this includes all two-cycle engines and most four-cycle
engines that are turbocharged.
The combustion control technologies available for lean-burn
engines are:
1. Adjustments to the A/F;
2. Ignition timing retard;
3. Combination of A/F adjustment and ignition timing
retard;
4. Selective catalytic reduction; and
5. Low-emission combustion.
5.2.1 Adjustments to the A/F for Lean-Burn Engines
5.2.1.1 Process Description. As shown previously in
Figure 5-1, increasing the A/F in lean-burn engines results in
lower NOX formation. The higher air content increases the heat
capacity of the mixture in the combustion chamber, which lowers
combustion temperatures and reduces NOX formation. To increase
5-41
-------
the A/F, the airflow must be increased or the fuel flow must be
decreased. Decreasing the fuel flow results in a derate in the
available power output from the engine, and so higher A/F's are
achieved by increasing the air flow (charge capacity) of the
engine. An increase in air charge capacity may require the
addition of a turbocharger to naturally aspirated engines and
modification or replacement of an existing turbocharger for
turbocharged engines.
5.2.1.2 Applicability. The A/F can be adjusted in the
field for most lean-burn engines. Pump-scavenged and blower-
scavenged two-cycle engines typically have no provisions for A/F
adjustment.8 To increase the air charge capacity, A/F adjustment
may require turbocharger modification or replacement and the
addition of a regulator system to control the air charge capacity
from the turbocharger if the engine is not already so equipped.
For effective NOX reductions, the addition of an automatic
A/F feedback controller may also be required to ensure sustained
NOX reductions with changes in engine operating parameters such
as speed, load, and ambient conditions. This automatic A/F
controller also maintains the proper A/F to avoid lean misfire
with changes in operating parameters.
5.2.1.3 Factors That Affect Performance. The degree to
which the A/F can be increased without exceeding the lean
flammability limit of the engine is the primary factor that
determines the potential NOX reduction that can be achieved with
this control technique. As this limit is approached, combustion
instability and engine misfire begin to occur. The extent to
which the A/F can be increased before the onset of combustion
instability is specific to each engine design and is influenced
by the air and fuel charging system.
To deliver the higher volume of air required to increase the
A/F, the turbocharger must either be able to deliver a higher
capacity or be replaced with a larger turbocharger. Some engine
designs may limit the extent to which the turbocharger capacity
can be increased due to physical space constraints on the air
5-42
-------
intake system or power output limitations on the existing engine
frame.
For engines that are fuel injected, the A/F for each
cylinder can be adjusted and so the A/F can be optimized in each
cylinder. Carbureted engines, however, can have significant
variations in the A/F from cylinder to cylinder due to less than
ideal distribution of air and fuel in the intake manifold. This
A/F variation requires that carbureted engines operate with a
richer A/F to ensure that the lean misfire limit is not exceeded
in any individual cylinder. Therefore, the extent that the A/F
can be increased is higher for fuel-injected engines than for
7ft
carbureted engines. °
An additional consideration is the duty cycle of the engine.
An engine's ability to respond to load changes decreases with
increases in the A/F.
5.2.1.2 Achievable Emission Reduction Using A/F Adjustment.
The achievable NOX emission reduction by A/F adjustment is
specific to each engine model. To understand the potential
effect of A/F adjustments on emissions for lean-burn engines, the
ratios at which the engine normally operates must be examined.
All two-cycle engines are classified as lean-burn because the
scavenge air used to purge the exhaust gases from the cylinder
results in exhaust 02 concentrations greater than 1 percent.
Figure 5-10 illustrates, however, that some two-cycle engines are
designed to operate at near-stoichiometric A/F's and therefore
respond to A/F adjustments in a manner similar to rich-burn
engines.
The four engines shown in Figure 5-10 are all two-cycle
designs, so they are classified as lean-burn. All four are from
the same manufacturer. Engines 1, 2, and 3 are the same engine
model and are rated at approximately 1,400 hp. Engine 4 is a
different model and is rated at approximately 3,500 hp.45 This
figure shows that each engine has a discrete operating A/F range
and corresponding NOX emission rate. The measured A/F is
referenced to the exhaust flow and includes both the combustion
A/F and the scavenge air flow. The emission rates indicate that
5-43
-------
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5-44
-------
Engines 1 through 3 operate at combustion A/F's that fall to the
left of the knee of the NOX curve (see Figure 5-1), and increases
in the A/F initially result in increases in NOX emissions. Of
these three engines, only Engine l achieves NOX reductions at the
upper limit of increases in the A/F.
Engine No. 4 operates at a higher combustion A/F range to
the right of the knee of the NOX curve shown in Figure 5-1, and
NOX reductions occur continuously with increases in A/F.
Emission test results for a similar lean-burn engine model are
shown in Figure 5-ll.4^ This figure shows emission rates for
four identical engines that operate at combustion A/F's to the
right of the knee of the NOX curve in Figure 5-1, and increases
in the A/F result in NOX emission reductions. (The composite
plot of filled dots in Figure 5-10 is based on empirical data and
does not necessarily reflect an achievable operating A/F range or
NOX emission signature for these engines.)
Figures 5-10 and 5-11 illustrate that while all two-cycle
engines are lean-burn, the effect of A/F adjustment on NOX
emission levels varies depending upon whether the engine is
designed to operate at A/F's that fall to the right or left of
the knee in the curve shown in Figure 5-1.
Using the midpoint of the A/F range as the baseline, the
potential NO., emission reductions were estimated for the engines
J^.
shown in Figure 5-10. Decreasing the A/F in Engines 1 through 3
results in NOX reductions ranging from approximately 10 to
15 percent. Increasing the A/F in Engine 4 results in a NOX
reduction of less than 10 percent. For the four engines shown in
Figure 5-11, increasing the A/F from baseline levels results in
NOX reductions ranging from approximately 20 to 33 percent.
Another report was available to quantify the achievable NOX
emission reductions using A/F adjustment for two lean-burn,
two-cycle, turbocharged engines.47 These engines are from two
different manufacturers, and each is rated at 3,400 hp. The
effect of increasing the A/F for one of these engines from an
established baseline exhaust A/F on emissions and BSFC is shown
in Figure 5-12. For this engine, NOX emissions decreased with
5-45
-------
80
70
60
O 50
40
30
I I t I I I I
I I I I • I I I I I I I I I I I I I I I I I
00
\
30 35 40 45 50
Air/Fuel Ratio
60
70
60
50
40
30
55 60
Figure 5-11.
The effect of A/F adjustment on NO emissions for
four identical lean-burn engines. °
5-46
-------
increasing A/F's, from 13.6 to 9.4 g/hp-hr, a reduction of
31 percent. There was little or no effect on CO emission levels;
HC emissions steadily increased from approximately 4 to
7 g/hp-hr, an increase of 75 percent. The initial effect on BSFC
was minimal, but at the highest acceptable (no engine misfire)
A/F, the BSFC was approximately 2.5 percent higher than at the
baseline level. A corresponding plot of the results of A/F
adjustment for the second engine was not presented, but the
report states that A/F adjustment was limited to a 5 percent
increase before the onset of lean misfire, and the NO,, emission
J\.
reduction was limited to 2 percent. Brake-specific fuel
consumption increased l percent. The manufacturer of this second
engine reports that, in general, A/F adjustment for its line of
engines has the potential to reduce NOX emissions up to
approximately 12 percent, with a resulting increase in BSFC of
less than 2 percent.7
Figures 5-10, 5-11, and 5-12 illustrate that the effect of
A/F adjustment on NOX emissions is engine model-specific. Among
engines of the same model, the effect of A/F adjustment is
similar, but the range of operating A/F's, and therefore the
achievable controlled emission levels, are engine-specific.
These figures also illustrate that because these engines can be
operated over a range of A/F's, the extent to which NOX emissions
can be reduced depends on where the engine is operating in this
range prior to adjustment of the A/F. For example, if Engine 4
in Figure 5-10 is operating at an A/F of approximately 42 prior
to adjustment, increasing the A/F to 45 or 46 reduces NOV
JC
emissions by about 1.5 g/hp-hr, a reduction of approximately 15
to 20 percent. However, if the engine is operating at an A/F of
45 or higher, little or no further adjustment to a higher setting
can be made, and little or no NOX reduction is possible from this
A/F set point.
Based on the data presented, it is estimated that A/F
adjustment for lean-burn engines achieves NOX emission reductions
ranging from 5 to 30 percent. A 25 percent reduction was used to
calculate controlled NO., emission levels and cost effectiveness
Jv
5-47
-------
r.n. (Encin* Operation) • A (Acceptable), SM <*o»« Misfire), EM (Exec*five Misfire)
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• BSFC
EM
46
48
50
1
4* 46 48 50
Exhaust A/F
52
52
9000
8500
8000
7500
54
7000
Figure 5-12.
The effect of A/F adjustment on emissions and fuel
efficiency for a lean-burn engine.47
5-48
-------
in Chapter 6. The data available to estimate the effect on CO
and HC emissions were limited, but based on the general emission
curves shown in Figure 5-1 and the data plotted in Figure 5-12,
the effect on CO emissions is minimal and HC emissions generally
increase. These effects on CO and HC are supported by
conclusions drawn from parametric testing of two other lean-burn
engines, which cited increases in HC emissions but found no
definite trends for CO emissions.48 The increase in BSFC is
estimated to be less than 5 percent, based on the data presented
in this section and the conclusions drawn in Reference 48.
5.2.2 Ignition Timing Retard
5.2.2.1 Process Description. Retarding the ignition
timing, as described in Section 5.1.2.1, initiates the combustion
process at a later point in the power stroke, which results in
reduced operating pressures and temperatures in the combustion
chamber. These lower pressures and temperatures offer the
potential for reduced NOX formation.
5.2.2.2 Applicability. Ignition timing can be adjusted in
the field on all lean-burn engines. As discussed in
Section 5.1.2.2, however, the existing ignition system usually
must be replaced with an electronic ignition and control system
to achieve sustained NO., reduction and satisfactory engine
J^.
operation with changes in operating conditions.
5.2.2.3 Factors That Affect Performance. Delaying the
combustion by ignition retard results in higher exhaust
temperatures, decreased speed stability, and potential for engine
misfire and decreased engine power output. These factors are
discussed in Section 5.1.2.3. These effects occur continuously
and proportionately with increases in timing retard, and limit
the extent to which the timing can be adjusted to reduce NOX
emissions.
5.2.2.4 Achievable Emission Reduction. As with A/F
adjustment, the achievable NOX emission reduction using ignition
timing retard is engine-specific. The effect of ignition timing
retard is shown in Figure 5-13 for four identical lean-burn
engines.4° (The composite plot of filled dots is based on
5-49
-------
1 U
65
60
55
50
45
40
35
in
i • i • i • i • i • i • .
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60
55
50
45
40
35
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0 2 4 6 6 10 12 14
Ignition Timing (D3TC)
Figure 5-13. The effect of ignition timing retard on NOX
emissions for four identical lean-burn engines.46
5-50
-------
empirical data and does not necessarily represent the extent to
which the ignition timing can be adjusted or the NOX emission
level for these engines.) This figure shows NOX emission
reductions ranging from approximately 3 to 15 percent for
ignition retard of up to 6° from the baseline setting of
8° before top dead center (BTDC). The source does not indicate
whether engine misfire occurred at the extremes of this 6° range
of timing retard.
The effect of timing retard on emissions and fuel
consumption is shown for another lean-burn engine in
Figure 5-14.47 A NOX reduction of less than 10 percent was
achievable before the onset of engine misfire with a timing
retard of between 3° to 6° from the baseline setting of 8° BTDC.
For moderate levels of timing retard, the effect on CO and HC
emissions is minimal for this engine. As the timing is further
retarded, CO emissions increase with the onset of engine misfire;
HC emissions decrease. The effect on BSFC is a continual
increase with increasing levels of retard. The increase is
approximately five percent for 4° of retard. The manufacturer of
this engine states that, in general, timing retard has the
potential to reduce NO., emissions for its line of engines by up
Jv
to approximately 25 percent. The corresponding increase in BSFC
•j
ranges up to 2 percent. For the other lean-burn engine in this
study, supplied by a different manufacturer, a 4° retard reduced
NOX emissions by 21 percent, with a minimal increase in BSFC.47
Further timing retard beyond 4° resulted in engine misfire.
The data suggest that NOX emission reductions are
engine-specific and range up to approximately 20 percent for
ignition timing retard levels of from 2° to 6° from the standard
setting. Attempts to further reduce NOX emission levels with
further timing retard results in engine performance deterioration
and misfire. A 10 percent reduction is used to calculate
controlled NOX emission levels and cost effectiveness in
Chapter 6. The impact on CO and HC emissions is minimal, a
conclusion supported in a report of parametric testing for two
additional lean-burn engines, which cites no definite trend for
5-51
-------
E.O. (Eagln« Operation) • A (Acceptable). SM (SoM Misfire), or CM (decisive Misfire)
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Ignition Tlmlnt, *BTDC
Figure 5-14.
The effect of ignition timing on emissions and fuel
efficiency for a lean-burn engine.47
5-52
-------
CO and only slight increases in HC levels. 8 The effect on BSFC
is an increase of up to 5 percent, based on the data presented
and the conclusions drawn in Reference 48.
5.2.3 Combination of A/F and Ignition Retard
A combination of A/F adjustment and ignition timing retard
can be used to reduce NOX emissions. The potential NOX reduction
for this combination is expected to be greater than for either
control technique used by itself but less than the sum of each
technique. A summary of emission tests performed before and
after adjustment of A/F and ignition timing for seven naturally
aspirated lean-burn engines is presented in Table 5-7.49
Engines 1 through 6 are the same engine model. The engines range
in size from 300 to 600 hp and were manufactured in the 1940's.
The NO... reductions resulting from the combination of control
J^:
techniques ranged from 2.7 to 48 percent and averaged 25 percent.
These data reflect the wide variation in achievable NO..
J^-
reductions, even for engines of the same model. The engine
manufacturer for Engines l through 6 estimates a potential NOX
reduction of approximately 20 to 35 percent for the combination
of these control techniques, with a corresponding increase in
BSFC of less than 5 percent.7 For either control technique used
independently, this manufacturer estimates a maximum achievable
NOX emission reduction of 12 and 25 percent for A/F and ignition
timing retard, respectively. Another source estimated that NOV
Ji.
reductions of up to 22 percent were possible without engine
performance deterioration and engine misfire for the engines
shown in Figures 5-12 and 5-14.47
Based on the limited information available, potential NOX
reductions using a combination of A/F adjustment and ignition
timing retard are estimated to range from 20 to 40 percent. This
is slightly higher than the estimated reductions of 5 to
30 percent for A/F adjustment and 0 to 20 percent for ignition
timing retard used independently. Again, the actual achievable
NOX emission reductions for the combination of these control
techniques are engine-specific. A reduction of 25 percent is
5-53
-------
TABLE 5-7. ACHIEVABLE NOX EMISSION REDUCTIONS FOR LEAN-BURN
ENGINES USING A COMBINATION OF A/F ADJUSTMENT AND IGNITION
TIMING RETARD49
Engine
No.
1
2
3
4
5
6
7
Average
Manufacturer
Dresser -Rand
Dresser -Rand
Dresser -Rand
Dresser-Rand
Dresser- Rand
Dresser-Rand
Cooper -Bessemer
Model
RA32
RA32
RA32
RA32
RA32
RA32
NA
Output
(hp)
300
300
300
300
300
300
600
N0x
reduction,
percent
25
2.7
48
27
26
39
8.4
25
5-54
-------
used to calculate controlled NOX emission levels and cost
effectiveness in Chapter 6.
Data were not available to quantify the effect of the
combination of A/F adjustment and ignition timing retard on CO
and HC emissions. Because the effect on CO and HC emissions is
minimal or a slight increase when these control techniques are
used independently, it is expected that the combination of
control techniques produces similar results.
5.2.4 Selective Catalytic Reduction
5.2.4.1 Process Description. Selective catalytic reduction
(SCR) is an add-on NOX control technology that is placed in the
exhaust stream following the engine. The SCR process reduces NOV
J^
emissions by injecting ammonia into the flue gas. A simplified
schematic of a SCR system is shown in Figure 5-15. The ammonia
reacts with NOX in the presence of a catalyst to form water and
nitrogen. In the catalyst unit, the ammonia reacts with NO..
J^
primarily by the following equations:50
4 NH3 + 6 NO •* 5 N2 + 6 H20; and
8 NH3 + 6 N02 -» 7 N2 + 12 H20.
The catalyst reactor is usually a honeycomb configuration,
as shown in Figure 5-16.51 Several methods of construction and
active material formulations are available. Base-metal (vanadium
or titanium) oxide or precious metal catalysts typically are .
constructed with a ceramic or metal substrate, over which the
active material is placed as a wash coat. Zeolite catalysts are
extruded as a homogeneous material in which the active material
is distributed throughout the zeolite crystalline structure. The
geometric configuration of the substrate is designed for maximum
surface area and minimum obstruction of the flue gas flow path to
maximize conversion efficiency and minimize back-pressure on the
engine.
An ammonia injection grid is located upstream of the
catalyst body and is designed to disperse the ammonia uniformly
throughout the exhaust flow prior to its entry into the catalyst
unit. In a typical ammonia injection system, anhydrous ammonia
is drawn from a storage tank and evaporated using a steam-heated
5-55
-------
ENGINE
NH-STORAGE TANK
EXHAUST
Figure 5-15.
Schematic of a selective catalytic
reduction system.
5-56
-------
Figure 5-16. Cutaway view of a honeycomb
catalyst configuration.51
5-57
-------
or electrically heated vaporizer. The vapor is mixed with a
pressurized carrier gas to provide both sufficient momentum
through the injection nozzles and effective mixing of the ammonia
with the flue gases. The carrier gas is usually compressed air
or steam, and the ammonia concentration in the carrier gas is
about 5 percent.^2
An alternative to using anhydrous ammonia is to use an
aqueous ammonia system. The diluted ammonia concentration in an
aqueous solution reduces the potential safety concerns associated
with transporting and storing anhydrous ammonia.
5.2.4.2 Applicability. The exhaust C>2 level of lean-burn
engines makes SCR applicable to all of these engines, but several
operating factors may limit the use of SCR. These factors are
fuel type and engine duty cycle. Contaminants in the fuel can
poison or mask the catalyst surface and reduce or terminate
catalyst activity. Examples of these contaminants are sulfur,
chlorine, and chloride, which are found in such fuels as digester
gas and landfill gas.27 Natural gas is free of these
contaminants, but fuels such as refinery gas, coal gas, and oil
fuels may have significant levels of one or more contaminants.
Phosphorus and ash in the engine lubricating oil also act as
catalyst masking and poisoning agents.
Sulfur-bearing fuels require special consideration when used
in SCR applications. Sulfur dioxide (S02), formed in the
combustion process, oxidizes to SOj in some catalysts. Unreacted
ammonia reacts with S03 to form ammonium bisulfate (NH4HS04) and
ammonium sulfate ((NH4)2S04)) in the low-temperature section of
the catalyst or waste heat recovery system. Ammonium bisulfate
is a sticky substance that causes corrosion of the affected
surfaces. Additionally, the deposits lead to fouling and
plugging of these surfaces and increase the back pressure on the
engine. This requires that the catalyst and any waste heat
recovery equipment be removed from service periodically to water-
wash the affected surfaces. Ammonium sulfate is not corrosive,
but like ammonium bisulfate, these deposits contribute to
plugging and fouling of the affected surfaces.
5-58
-------
Formation of ammonium salts can be minimized by limiting the
sulfur content of the fuel and/or limiting the ammonia slip. The
detrimental effects of catalyst masking, poisoning, and ammonium
salt formation can also be minimized by using a zeolite catalyst,
according to one catalyst vendor. Zeolite is a highly porous
crystalline structure; 1 gram of zeolite can contain up to
3,000 square feet of catalyst surface. The catalytic reaction
does not take place on the surface of the catalyst but rather in
the molecular sieve of the crystalline structure. The NOX and
NH3 diffuse into the molecular-sized cavities of the crystalline
structure, and the exothermic reduction reaction forcefully
expels the products of the reaction from the cavities in a
self-cleansing action. Because the reducing reaction takes place
within the molecular sieve, effects of masking and poisoning that
occur on the surface of the catalyst have a minimal effect on the
catalyst reduction efficiency.5-^'54 The catalyst vendor cites
experience with natural gas-fired two-cycle engines with lube oil
consumption rates three times greater than those usually seen
from this type of engine. An independent lab test performed on
samples of the catalyst after 1,000 operating hours showed that
concentration levels of phosphorus, sulfur, and zinc found on the
surface of the catalyst rapidly diminished from the catalyst
surface to the center of the channel wall. The original
catalysts at this installation have operated for over 6 years
with a NOX reduction efficiency loss of less than 5 percent. In
addition, zeolite has an inherent S02 to S03 conversion rate of
less than 0.1 percent, so ammonium salt formation is minimized.55
The duty cycle of the engine should also be considered in
determining the applicability of SCR. Exhaust temperature and
NOX emission levels depend upon engine power output, and variable
load applications may cause exhaust temperature and NOY
Jt
concentration swings that pose problems for the SCR system. The
lower exhaust temperature at reduced power output may result in a
reduced NOX reduction efficiency from the catalyst. It should be
noted, however, that exhaust NOX concentrations are lower at
reduced power output, and residence time in the catalyst is
5-59
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higher, which would offset to some extent the lower catalyst
reduction efficiency at reduced temperatures. The variation in
NOX concentrations in the exhaust caused by changes in power
output requires that the ammonia flow be adjusted to maintain the
proper NH3/NOX ratio. As the exhaust flow rate and NOX
concentration level vary, the NH3 injection rate must change
accordingly to avoid increased levels of unreacted NH3 emissions
(ammonia slip) and maintain NOX reduction efficiency. At least
three catalyst vendors offer an NH3 injection control system for
use in variable load applications. These systems are discussed
in Section 5.2.4.4.
5.2.4.3 Factors That Affect Performance. The factors that
affect the performance of SCR are catalyst material, exhaust gas
temperature, space velocity, the NH3/NOX ratio, and the presence.
of catalyst contaminants in the exhaust gas stream.
Several catalyst materials are available, and each has an
optimum NOX removal efficiency range corresponding to a specific
temperature range. Proprietary formulations containing titanium
oxide, vanadium pentoxide, platinum, or zeolite offer wide
operating temperature ranges and are the most common catalyst
materials. The NOX removal efficiencies for these catalysts are
typically between 80 and 90 percent when new; over time, the NOX
removal efficiency may drop as the catalyst deteriorates due to
surface deposits, poisoning, or sintering.51
The space velocity (volumetric flue gas flow rate divided by
the catalyst volume) is essentially the inverse of residence time
in the catalyst unit. The lower the space velocity, the higher
the residence time, and the higher the potential for increased
NO., emission reductions. Since the exhaust gas flow is dictated
Jt
by the engine, the space velocity is largely dependent upon the
size of the catalyst body. Lower space velocities require larger
catalyst bodies.
The NH3/NOX ratio can be varied to achieve the desired level
of NO... reduction. The SCR systems generally operate with a molar
Jv
NH3/NOX ratio of approximately l.O.51 Increasing this ratio will
5-60
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further reduce NOX emissions but will also result in increased
ammonia slip.
Contaminants in the exhaust gas stream will mask or poison
the surface of the catalyst reactor. Masking agents, such as
sulfur and ash, deposit on the catalyst surface and require that
the catalyst be mechanically cleaned to restore lost catalyst
activity. Poisoning agents such as chlorine and phosphorus
chemically alter the catalyst material, and any resulting loss of
catalyst activity is permanent. The source of most contaminants
is gaseous fuels other than natural gas; ash and phosphorus are
found in lubricating oils. Low-ash and low-phosphorus
lubricating oils are available and are recommended for use with
catalyst systems.27 The use of low-ash oils may have a
detrimental effect on the valve life of some four-cycle engines.
Past experience has shown that the exhaust valve life of some
engines may be reduced be as much as 50 percent, doubling the
frequency of top-end overhaul maintenance requirements of the
engine.56
5.2.4.4 Achievable Emission Reduction Using SCR. Based on
information provided by catalyst vendors, a total of
23 gas-fired, lean-burn engine SCR applications have been
installed or will be installed in the United States by the end of
1993. Of these installations, three are used in digester gas
applications, and the rest are natural gas-fueled. From the
information provided it was not possible to confirm that this
list includes all SCR installations in the United States or
whether any of these installations have been decommissioned.
Operating experience and emission test summaries for 16
engines at 9 installations in California were provided by one
catalyst vendor and are shown in Table 5-8.57 For these
installations, NOX reduction levels range from 75 to 90 percent,
with corresponding NH3 slip levels of 20 to 30 ppmv. All but one
of these installations uses a manually adjusted NH3 injection
control system. The controlled NOX emission and ammonia slip
levels for the two digester gas-fired applications are similar to
those for the natural gas-fired engines shown in this table.
5-61
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5-62
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Emission compliance test summaries were also reported in the
VCAPCD emission data base for six SCR installations. These test
summaries are shown in Table A-5 in Appendix A.24 For a total of
34 test summaries, only 1 did not achieve compliance with the
controlled NOX requirement of 125 ppmv or 80 percent reduction,
and the data base reports that this engine was removed from
service. Of the five remaining SCR installations, two other
engines were in compliance, but were removed from service and
replaced by electrification. Controlled NO., emission levels for
Jt
those engines in compliance range from 10 to 222 ppmv (0.14 to
3.1 g/hp-hr), with corresponding reduction efficiencies of 65 to
97 percent. The data base shows that two of these SCR
installations have been operating within compliance limits for
over 5 years. Information regarding catalyst maintenance
requirements and replacement schedules for these engines was not
available. Ammonia slip levels were not reported in the data
base. (Rule 74.9 for VCAPCD and Rule 1110.2 for SCAQMD do not
include ammonia emissions limits.)
In addition to the experience described above for
U.S. installations, one zeolite catalyst vendor also provided SCR
operating experience for engine installations worldwide. The
installation list shows over 40 gas-fired engine applications
using natural gas, landfill and digester gases, and mining gases.
Applications include power generation and cogeneration, natural
gas pipeline compression, and district heating. Seven of these
installations have been in service since 1985, and one of these
installations has operated for over 6 years with only a 5 percent
loss in NOX reduction efficiency. The two-cycle engines in this
installation consume three times more lubrication oil than is
considered normal by the catalyst vendor. The guaranteed minimum
NOX reduction at this site is 85 percent.53'54
Catalyst vendors typically offer NO... reduction efficiency
J\.
guarantees of 90 percent, with an ammonia slip level of 10 ppmv
or less. The performance is guaranteed by most vendors for
3 years for natural gas-fired applications.34 One zeolite
catalyst vendor offers a guarantee of up to 95 percent NOX
5-63
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reduction with an ammonia slip limit of 10 ppmv or less for
2 years.54
As discussed in Section 5.2.4.2, NOX emission levels and
exhaust flow vary with changes in engine load, and the NH3
injection rate must follow these changes. Several catalyst
vendors state that NH3 injection system controls are available
for variable load applications. One vendor's design has been in
use since 1988, but system design details were not available.55
Another vendor offers a load-foilowing ammonia injection control
system design for the installations shown in Table 5-8, dating
back to 1989. These installations have achieved NOX emission
reductions of 75 to 90 percent with NH3 emission slip levels of
20 to 30 ppmv, based on 15 minute emission averaging.57
Information regarding the extent and frequency of the engine load
changes, however, were not available. Information for a
microprocessor-based, feedforward/feedback NH3 injection control
system was provided by a third vendor. This system is available
with provisions to predict NOX emissions based on engine
operating parameters. The predictive emission maps are developed
either by the engine manufacturer or by the catalyst vendor
during the start-up/commissioning, phase of the project, and these
maps can be automatically updated periodically by the
microprocessor system, based on historical operating data. The
feedforward control regulates the NH3 injection rate consistent
with the anticipated NOX emissions, and the injection rate is
trimmed by the feedback controller, which monitors emission
levels downstream of the catalyst reactor. A deadtime
compensation routine is incorporated into the control scheme to
compensate for the difference between the catalyst reactor
reduction rate and the controller response time. This control
scheme is operating in Europe and at a demonstration site in the
United States, and typical deviations from the target NOX
C Q
emission setpoint are within 4 percent. °
Based on the available information and the emission test
daia presented in Tables 5-8 and A-5, it is estimated that the
achievable NOX emission reduction for SCR in gas-fired
5-64
-------
applications is 80 to 90+ percent for baseload applications, with
an NH3 slip level of 10 ppmv or less. A 90 percent NOX reduction
is used in Chapter 6 to calculate controlled NOX emission levels
and cost effectiveness. The available data are not sufficient to
assess the achievable continuous NOX reductions and ammonia slip
levels for SCR used in variable load applications. Emissions of
CO and HC are not significantly affected by the use of SCR.11
The backpressure on the engine increases by approximately
2 to 4 in. w.c. with the installation of an SCR system. The
resultant BSFC increase from a backpressure of 4 in. w.c. is
estimated at 0.5 percent.3 This backpressure also is estimated
to decrease the power output by 1 percent in naturally aspirated
engines and 2 percent in turbocharged engines.3
5.2.5 Low-Emission Combustion
5.2.5.1 Process Description. Lean-burn engine NO..
J\f
emissions can be reduced by increasing the A/F so that the engine
operates in the region depicted on the right side of Figure 5-1.
These low-emission combustion designs are also referred to as
torch ignition, jet cell, and CleanBurn® by various
manufacturers. (CleanBurn® is a registered trademark of Cooper
Industries.) The increase in the air content serves to raise the
heat capacity of the mixture and results in lower combustion
temperatures, which lowers NOX formation. This increased airflow
is provided by adding a turbocharger and intercooler or
aftercooler to naturally aspirated engines or by replacing an
existing turbocharger and inter/aftercooler with a
larger-capacity unit. The air intake and filtration system,
carburetor(s), and exhaust system must also be replaced to
accommodate the increased flows.
Substantial modification of the combustion chamber is
required to ensure ignition and stable combustion of the higher
A/F mixture. For engines that have a relatively small cylinder
bore, the combustion chamber may use an open cylinder design,
which is similar to a conventional combustion chamber but
incorporates improved swirl patterns to promote thorough mixing.
Larger cylinder bores cannot reliably ignite and sustain
5-65
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combustion with an open-cylinder design and a PCC. These
clean-burn combustion designs vary somewhat with each
manufacturer, but descriptions and representative sketches are
presented in Section 5.1.6.1. The redesigned combustion chamber
in the case of either an open or PCC design usually requires
replacement of the intake manifolds, cylinder heads, pistons, and
the ignition system.
5.2.5.2 Applicability of Low-Emission Combustion. The
applicability of combustion modifications for lean-burn,
low-emission engines is limited only by the availability of a
conversion kit from the manufacturer. The application
considerations discussed for rich-burn engines in Section 5.1.6.2
also apply to lean-burn engines.
5.2.5.3 Factors That Affect Performance. The factors that.
most affect the emissions reduction performance of a lean-burn
engine that has been converted to low-emission combustion are the
design of the new combustion chamber and the volume of air that
can be delivered. The factors described in Section 5.1.6.3 for
rich-burn engines also apply to lean-burn engines.
5.2.5.4 Achievable Emission Levels Using Low-Emission
Combustion. The nominal emission levels provided by engine
manufacturers for both 2-cycle and 4-cycle PCC designs are:37"42
Emissions, g/hp-hr
NOY
1.5-3.0
CO
0.6-3.5
HC
1.0-9.0
Emissions, ppmv at 15% 0?
NOV
110-225
CO
72-425
HC
217-1,950
Reductions in NOV emissions using combustion modifications
J^
generally result in higher CO and HC emission levels. For this
reason, it is not likely that the low end of each range for NOX/
CO, and HC in the figure listed above can be achieved
simultaneously.
There was no discernable difference in achievable emissions
levels between applying combustion controls to 2-cycle versus
4-cycle engines. (Two low-emission engine models from one
manufacturer that have controlled NOX emissions of 6.5 g/hp-hr
5-66
-------
[475 ppmv] were not included in the above table. These models
will soon be updated, and controlled NOX emissions will be within
the range shown above.)
The percent NOX reduction that is achievable by converting a
lean-burn engine to a low-emission design varies depending upon
the uncontrolled and controlled NOX levels used to calculate the
percent reduction. Uncontrolled emission levels typically range
from 15 to 20 g/hp-hr for lean-burn engines.^7"42 Conversion to
clean-burn operation can achieve controlled NOX emission levels
of 1.5 to 3.0 g/hp-hr. The percent reduction, therefore, ranges
from 80 to 93 percent.
Test results for nine low-emission engines that were
developed from lean-burn engine designs are presented in
Table 5-9.5^'^2 Four of these engines are retrofit
installations; the other five were installed as new equipment.
This table shows that controlled NOX emission levels range from
0.53 to 6.0 g/hp-hr (40 to 450 ppmv), and average 2.0 g/hp-hr
(154 ppmv}. The 6.0 g/hp-hr level for engine No. 7 is not
considered to be representative of the achievable controlled NOV
Jt
emission level, since engine Nos. 6 and 7 are the same engine
model and engine No. 7 achieved a 1.5 g/hp-hr emission level.
The average NO., emission level drops from 2.0 to 1.6 g/hp-hr
J^
(154 ppmv) if engine No. 6 is not included. Carbon monoxide
emission levels range from 1.05 to 2.2 g/hp-hr (126 to 264 ppmv)
and average 1.6 g/hp-hr (192 ppmv). Hydrocarbon emissions range
from 0.3 to 4.4 g/hp-hr (53 to 933 ppmv) and average 1.2 g/hp-hr
(262 ppmv). All of these engines use a PCC design, and the
controlled emission levels are within or below the achievable
ranges stated by the engine manufacturers.
Emission test results for several low-emission engines were
also included in the VCAPCD emission data base.24 These emission
summaries are presented in Table A-4 in Appendix A. For a total
of 64 emission tests performed on six engines, all but 5 of the
tests show controlled NOX emission levels of less than 100 ppmv
(1.34 g/hp-hr), and average the 75 ppmv (1.0 g/hp-hr), with
average controlled CO and HC emission levels of 500 ppmv
5-67
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(4.17 g/hp-hr) and 127 (0.60 g/hp-hr), respectively. The NOX and
HC emission levels are consistent with those stated by engine
manufacturers, but the CO emission levels are generally higher.
No information was available to explain these relatively elevated
CO emission levels, but the range shown in Table A-4 is well
within the VCAPCD CO limit of 4,500 ppmv.
The data presented suggest that achievable controlled NOX
emission levels of 1.0 to 2.0 g/hp-hr (75 to 150 ppmv) can be
achieved with combustion modifications for either new or retrofit
lean-burn engine installations. A 2.0 g/hp-hr controlled NOX
emission level is used in Chapter 6 for cost effectiveness
calculations. This is also the controlled NOX emission range for
combustion modifications for rich-burn engines. Emission levels
for CO and HC vary for different engine models and even among
engines of a given model, but most range from approximately 1.0
to 5.0 g/hp-hr (120 to 600 ppmv) for CO and 0.5 to 4.0 g/hp-hr
(110 to 500 ppmv) for HC.
The operating characteristics of low-emission combustion,
including a substantially leaner A/F and the potential increase
in operating pressures from turbocharging, suggest improved fuel
economy. Information for four manufacturers' engines for which
comparable heat rates were provided shows that the effect of the
combustion modification on engine heat rates was mixed. The
effect ranged from an increase in heat rate of as much as
3.5 percent to a decrease of as much as 12.4 percent.37'3**'40'42
5.3 NOX CONTROL TECHNIQUES FOR CI ENGINES
Both diesel and dual-fuel engines operate with significant
excess 02 levels in the exhaust gas stream. Although classified
as lean-burn, the effect of control techniques applied to these
CI engines is in many cases different from those for SI engines.
Therefore, the discussion of control techniques applied to CI
engines is presented separately.
The control technologies available for CI engines are:
1. Injection timing retard;
2. Selective catalytic reduction; and
5-69
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3. Low-emission combustion (dual-fuel engines only).
Section 5.3.1 describes the performance of NOX control techniques
for diesel engines. The performance of NOX control techniques
for dual-fuel engines is discussed in Section 5.3.2.
5.3.1 Diesel Engines
5.3.1.1 Injection Timing Retard for Diesel Engines. In a
CI engine, the injection of the fuel into the cylinder initiates
the combustion process. Retarding the timing of the fuel
injection initiates the combustion process later in the power
stroke when the piston is in its downward motion and the
combustion chamber volume is increasing. This increasing volume
lowers combustion temperatures and pressures, thereby lowering
NOX formation. Along with NOX reductions, injection timing
retard increases both black smoke and cold smoke (white smoke
during start-up) emissions, increases exhaust temperatures, and
can make starting the engine at cold temperatures more difficult.
Brake-specific fuel consumption also increases with timing
retard.63,64 -J^Q sources report that power output decreases by
roughly the same amount as BSFC increases.64'65 Another engine
manufacturer, however, reports that injection timing retard does
not reduce power output for its line of engines.63 The increase
in exhaust temperatures affects turbocharger performance and may
be detrimental to exhaust valve life.63'65 Excessive timing
retard causes engine misfire.67 These performance impacts
generally limit the extent of injection timing retard to less
than 8° from the standard setting.63
Injection timing to retard the ignition can be adjusted in
the field on all diesel engines. For maximum NOX reduction, an
electronic injection timing system is required, which temporarily
advances the timing during start-up and under acceleration in
response to load changes.63'65
Injection timing retard reduces NOX emissions from all
diesel engines, but the magnitude of the reductions is specific
to each engine model. The effectiveness of injection retard on
decreasing NOX formation diminishes with increasing levels of
retard. Data to quantify the effects of injection timing retard
5-70
-------
were available from only one manufacturer for retard levels
between 3° and 5°. These data are shown in Table 5-10.66 The
results from three different engines show that injection retard
reduced NOX emissions in all three engines by greater than
20 percent, but the magnitude of the reduction varied for each
engine. Another manufacturer estimated achievable NOX reduction
potential for injection timing retard ranges up to 50 percent.63
Data from Reference 5 indicate that NOX reductions range from
20 to 34 percent. Based on the available data and estimates by
manufacturers, the expected range for NOX reductions using
injection timing retard in diesel engines is 20 to 30 percent. A
25 percent reduction is used to calculate controlled NOX emission
levels and cost effectiveness in Chapter 6. The actual NOX
reduction, however, is engine-specific and may be higher or lower
than the expected range.
The effect on CO emissions shown in Table 5-10 is an
increase for two of the engines and a decrease for the third
engine. The overall impact on CO emissions, whether an increase
or a decrease, is a change of less than 15 percent for these
engines. The effect on HC emissions also varies among engines,
ranging from no change to an increase of 76.2 percent. The BSFC
increases for all three engines. The magnitude of the fuel
increase grows with the degree of retard, ranging from
0.9 percent for a 3° retard to 4.5 percent for a 5° retard.66 In
general, the effect of reducing NOX emissions by fuel injection
retard on CO and HC emissions is estimated to range from a
10 percent decrease up to 30 percent increase for CO and
+/- 30 percent change for HC, according to one manufacturer. The
increase in BSFC is a maximum of 5 percent.63 The effect on CO
and HC emissions and BSFC for the engines shown in Table 5-10,
although produced by another manufacturer, is generally
consistent with these estimates.
5.3.1.2 Selective Catalytic Reduction. The process
description for SCR discussed in Section 5.2.4.1 applies to
diesel engine applications. Selective catalytic reduction
applies to all diesel engines, and the application considerations
5-71
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discussed in Section 5.2.4.2 for SI engines also apply to diesel
engines. The factors that affect the performance of SCR for
diesel engines are the same as those discussed in
Section 5.2.4.3. Fuel specifications for No. 2 diesel fuel limit
the sulfur content to 0.5 percent. Heavier diesel fuels may have
higher sulfur contents, however, that may result in increased
formation of ammonia salts (see Section 5.2.4.2).
The potential NOX emission reductions for SCR applications
with diesel engines are similar to those for natural gas
applications. Catalyst vendors that offer zeolite catalysts
quote NOX reduction efficiencies for diesel engine applications
of 90 percent or higher, with corresponding NH^ slip levels of
10 ppmv or less.54'68
According to one of these vendors, the crystalline molecular
structure of zeolite, combined with the exothermic
characteristics of the NOX and NHj reducing reaction, minimizes
the masking and poisoning problems that have been experienced
with base metal catalysts. Zeolite also has a S02 to SOj
conversion rate of less than 0.1 percent, so ammonia salt
formation is minimal.55 The two zeolite vendors contacted for
this study have diesel engine installations using SCR outside of
the United States for which these 90 percent NOX reduction
efficiencies are guaranteed for 3 years, but to date they have no
installations in the United States. A total of nine oil-fired
zeolite installations were identified.54'69 All of these
installations are overseas, mostly in Europe. Of these
installations, eight engines are diesel-fired; the other is
fueled with heavy oil. These installations date back as far as
1985, and the catalyst vendors guarantee a 90 percent NOV
Jv
reduction or higher, with an ammonia slip level of 10 ppmv or
less, for 3 years. One of these diesel-fired installations has a
3-year guarantee of 95 percent NOX reduction with an maximum
ammonia slip level of 5 ppmv. The heavy oil-fired installation
was installed in 1985.
To date there are no zeolite SCR installations in
diesel-fired applications in the United States, but a U.S. SCR
5-73
-------
installation with a 6,700 hp dual-fuel engine achieved over
30,000 hours before one quarter of the original catalyst was
replaced. This engine operates up to 25 percent of the time in a
diesel mode, firing 100 diesel oil, and it is estimated that the
original catalyst operated up to 7,500 of the 30,000+ total hours
on diesel fuel, maintaining a guaranteed NOX reduction of
93 percent or higher with an ammonia slip level of less than
10 ppmv. The only catalyst maintenance requirement at this site
is periodic vacuuming of the catalyst face to remove particulate
matter, which is attributed to engine lube oil consumption. This
accumulation of particulate matter is manifested by an increase
in pressure drop across the catalyst from a design 3.5 in. w.c.
to 5+ in. w.c. No notable decrease in catalyst reduction
performance accompanies this pressure drop.70
The NOX reduction efficiency quoted by vendors offering
base-metal catalysts for diesel applications is typically 80 to
90 percent.57'71 The exhaust from diesel engines has a higher
level of heavy hydrocarbons than natural gas-fueled engines, and
these hydrocarbons lead to soot formation on the catalyst
surface, which can mask the catalyst and reduce the NOX reduction
activity.50 A guard bed, having the same structural makeup as
the catalyst material, is usually installed upstream of the
catalyst body in diesel applications to collect the heavy
hydrocarbons that would otherwise mask the base-metal catalyst.
This guard bed is replaced approximately every 2,000 hours of
operation.72
Only two vendors offering base metal catalysts contacted for
this study have SCR installations operating with diesel engines.
The majority of these installations are in emergency power
generation service and have accumulated relatively few operating
hours. One base-metal catalyst vendor's diesel-fired SCR
experience is presented in Table 5-11 and shows six
U.S. installations with a total of nine engines.57 All of these
SCR applications are load-following, but details of the duty
cycle and the ammonia injection control scheme were not provided.
The reported NO^ emission reductions range from 88 to 95 percent,
J\,
5-74
-------
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5-75
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with corresponding ammonia slip levels of 5 to 30 ppmv. The
tests were performed in accordance with State-approved methods
for California, with emissions reported on a 15-minute averaging
basis. The first of these installations was installed in 1989,
and one installation has operated over 12,000 hours to date.
The available data show diesel-fired SCR applications using
either zeolite or base-metal catalysts achieve NOX reduction
efficiencies of 90+ percent, with ammonia slip levels of 5 to
30 ppmv. These installations include both constant- and
variable-load applications. Experience to date, however,
especially in the United States, is limited in terms of both the
number of installations and the operating hours. A 90 percent
reduction is used in Chapter 6 to calculate controlled NO..
H
emission levels and cost effectiveness.
As discussed in Section 5.2.4.4, the effect of SCR on CO and
HC emissions is minimal. The engine BSFC increases with the use
of SCR due to the increased exhaust backpressure created by the
catalyst reactor.
5.3.2 Dual- Fuel Engines
5.3.2.1 Injection Timing Retard for Dual-Fuel Engines.
Fuel injection timing retard reduces NOX emissions from dual-fuel
engines. The process description, extent of applicability, and
the factors that affect performance are the same as for diesel
engines and are discussed in Section 5.3.1.1.
The achievable NOX emission reductions range from 20 to
30 percent for a timing retard of 4°, based on information and
data in Reference 5. The actual reduction is specific to each
engine. Additional data were available only for one engine and
are presented in Table 5-12.65 This table shows that a timing
retard of 3° results in a NOX reduction of 14 percent. An
additional retard of 3° yields an additional 5 percent NOX
reduction. The nominal NOX emission rate for this engine is
5 g/hp-hr.38 Reductions of 14 and 19 percent result in
controlled NOX emissions of 4.3 and 4.1 g/hp-hr, respectively.
The total NOX reduction figure of 19 percent for a 6° timing
retard is slightly lower than the 20 to 30 percent reduction
5-76
-------
TABLE 5-12.
RESULTS OF RETARDING THE INJECTION TIMING FOR ONE
DUAL-FUEL ENGINE MODEL65
Affected parameter
NOV emissions
CO emissions
HC emissions
Fuel consumption
Percent change due to
retarding from 21° to
18° BTDC
-14
+ 13
+6
+ 0.7
Percent change due
to retarding from
18° to 15° BTDC
-5
+ 10
+15
+2.5
5-77
-------
range stated in Reference 5. A 20 percent reduction was used in
Chapter 6 to calculate controlled NOX emission levels and cost
effectiveness.
Timing retard increases emissions of CO and HC as well as
BSFC. Table 5-12 shows that the initial 3° timing retard
increases CO and HC emissions 13 and 6 percent, respectively.
The BSFC increased 0.7 percent. This table also shows the
diminishing NOX reduction benefit and the rise in the rate of
increase of other emissions and fuel consumption with incremental
increases in timing retard. The increase in timing retard from
3° to 6° yielded an additional NOX reduction of 5 percent, while
CO and HC emissions increased an additional 10 and 15 percent,
respectively, and fuel consumption increased an additional
2.5 percent.
5.3.2.2 Selective Catalytic Reduction for Dual-Fuel
Engines. The process description, extent of applicability, and
the factors that affect the performance of SCR for dual-fuel
engines is the same as for CI engines and is discussed in
Section 5.3.1.
Catalyst vendors report a total of 27 U.S. SCR systems
installed to date with dual-fuel engines.58'70 The achievable
NOX emission reduction using SCR with dual-fuel engines ranges
from 80 to 90+ percent. Two vendors with SCR installations in
the United States using zeolite catalysts have guaranteed
90 percent or higher NO,, reduction efficiencies with a 10 ppmv or
Jv
less ammonia slip for a 3-year period.54'68 The first SCR
installation in the United States was installed downstream of a
6,700 hp dual-fuel engine in 1988. The NOX reduction guaranteed
at this site is 93 percent, with an ammonia slip level of less
than 10 ppmv. The results of an emission test performed during
commissioning in 1989 at this site are presented in Table 5-13.73
Controlled NOX emission levels averaged 0.38 and 0.22 g/hp-hr
(48.3 and 27.1 ppmv) for operation on diesel and dual-fuel,
respectively. Ammonia slip levels were not reported in the test
results. Catalyst life was guaranteed for 3 years or
20,000 hours. The SCR system achieved over 30,000 operating
5-78
-------
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hours before one of the four sections of the original catalyst
was replaced. This engine operates up to 25 percent of the time
in a diesel mode, and on this basis it is estimated that the
catalyst has operated up to 7,500 of the 30,000+ total hours on
diesel fuel. The only catalyst maintenance requirement at this
site is periodic vacuuming of the catalyst face to remove
particulate matter, which is attributed to engine lube oil
consumption. This accumulation of particulate matter is
manifested by an increase in pressure drop across the catalyst
from a design 3.5 to 5+ in. w.c. No notable decrease in catalyst
reduction performance accompanies this pressure drop. No other
site-specific emission data were available for dual-fuel SCR
applications.
The limited data suggest that a NOX emission reduction of
80 to 90 percent is achievable using SCR with dual-fuel engines.
The experience with this control technique to date is limited,
however, especially in the United States. A 90 percent reduction
was used in Chapter 6 to calculate controlled NOX emission levels
and cost effectiveness.
As discussed in Section 5.2.4.4, the effect of SCR on CO and
HC emissions is minimal. The engine BSFC increases with the use
of SCR due to the increased exhaust backpressure created by the
catalyst reactor.
5.3.2.3 Low-Emission Combustion for Dual-Fuel Engines.
Engine manufacturers have applied some of the design features
used in SI low-emission engines to dual-fuel engines.
Information was available from two manufacturers for low-emission
dual-fuel engines that use a PCC design similar to that used for
SI engines.74'75 The PCC makes it possible to reduce the
injection rate of oil pilot fuel used for ignition from the
conventional 5 to 6 percent level down to approximately 1 percent
while maintaining acceptable combustion stability. In addition
to the PCC, the low-emission engines also use a higher A/F in the
main combustion chamber and ignition retard to reduce NOX
emission levels. In addition to reduced NOX emission levels, the
reduced pilot oil injection rate also reduces the yellow plume
5-80
-------
associated with dual-fuel engine exhaust, according to one
manufacturer.75
The manufacturers report that emission reductions using the
low-emission PCC designs are achieved only in the dual-fuel
operating mode. Emission levels for the diesel operating mode
(100 percent diesel fuel) are essentially unchanged.
These low-emission designs are available for both new and
retrofit installations, although information was not available to
determine the extent of availability for retrofit applications,
especially those engines that are no longer in production.
Minimum retrofit requirements include modification or replacement
of the engine heads, fuel system and controls, and
turbocharger.75
Nominal emission levels for two manufacturers' low-emission.
dual-fuel engines are presented in Table 5-14 and are compared to
corresponding emission levels for conventional open-chamber
designs.3®'41'74'75 Achievable controlled NO... emission levels
JL
range from 1.0 to 2.0 g/hp-hr (75 to 150 ppmv), a reduction of
60 to 78 percent from open-chamber combustion NOX levels. The
effect on CO and HC emissions appears to be engine-specific, as
one manufacturer reports increases in both CO and HC while the
other reports no change in CO and a decrease in HC emissions.
Fuel consumption increases for the low-emission engines in both
designs, with increases ranging from 1.6 to 3.1 percent.
Emission test results for retrofit application of a
low-emission PCC design were available only for one
manufacturer's engines and are presented in Table 5-15. The
first engine was retrofit and tested in-house by the
manufacturer.75 The second engine was retrofit and tested in the
rjC
field./D These tests show that NOX emissions from the first
engine were reduced with the PCC design by over 90 percent, and
the engine achieved a controlled NOV emission level of
Jv
0.9 g/hp-hr (68 ppmv). Carbon monoxide emissions were not
recorded. Total HC emission levels increased by nearly
400 percent, but uncontrolled HC levels prior to installation of
the PCC design were very low. The controlled HC level of
5-81
-------
TABLE 5-14. NOMINAL EMISSION LEVELS COMPARING OPEN- CHAMBER AND
PRECOMBUSTION CHAMBER DESIGNS FOR DUAL FUEL ENGINES38*41'74' '5
Emissions, g/hp-hr
NOV
CO
THCa
BSFC
Btu/hp-hr
E- Series Turbocharged Engine (dual -fuel mode)
Open- chamber*5
Enviro-
Design®*5
Percent change
4.5
1.0
-78
1.3
2.0
+ 54
2.0
2.5
+25
6,100
6,290
+3.1
LSVB Engine (dual -fuel mode)
Open chamber
CleanBurn®
Percent change
5.0
2.0
-60
2.0
2.0
NCC
7.0
5.0
-29
6,200
6,300
+ 1.6
f^Total hydrocarbon emissions
"900 rpm engine speed.
CNC - no change.
5-82
-------
TABLE 5-15. EMISSION TEST RESULTS FOR A LOW-EMISSION DUAL-FUEL
ENGINE RETROFIT WITH A PRECOMBUSTION CHAMBER75'76
Emissions, g/hp-hr
NOY
CO
THCa
BSFC
(Btu/hp-hr)
Smoke
(Opacity,
percent)
LSB-6 Engine (dual -fuel mode, in-house tests)
Open -chamber
CleanBurn®
Percent change
11.5
0.9
0.92
NAb
NAb
NAb
1.0
4.9
+390
6,230
6,330
+1.6
NAb
NAb
NAb
LSVB-20 engine (dual-fuel mode, average of 3 tests at site)
CleanBurn®
1.27
1.60
3.48
NAb
0-5
f-Total hydrocarbon emissions.
bNA - data not available.
5-83
-------
4.9 g/hp-hr (1,040 ppmv) for this engine is within the expected
range of 5.0 g/hp-hr stated by the manufacturer and shown in
Table 5-14. Fuel consumption increased for the low-emission
design by 1.6 percent.
The test results in Table 5-15 for the second engine are for
an existing 6.0 MW (8,000 hp) dual-fuel engine installation that
was retrofit with the PCC design in 1990.76 Emission test
results following this retrofit show that controlled NOX emission
levels at full-load conditions average 1.27 g/hp-hr (95 ppmv).
Pre-retrofit emission levels were not reported, but the operator
reports that this controlled NOX level represents a reduction of
68 percent from average pre-retrofit levels of greater than
4.0 g/hp-hr (300 ppmv). Controlled CO and HC emissions average
1.60 and 3.48 g/hp-hr (190 and 740 ppmv), respectively. The
operator reports controlled HC levels are lower than pre-retrofit
levels; the effect of the retrofit on CO emission levels was not
clearly stated in the reference. The effect of the retrofit on
BSFC also could not be determined. The manufacturer of this
engine reports that exhaust opacity is reduced with the PCC
design and virtually eliminates the yellow plume associated with
dual-fuel engines.7^ The test results show that opacity was
reduced to 0 to 5 percent, compared to 10 to 20 percent prior to
the retrofit.76
Based on the limited data presented in this section, it is
estimated that controlled NOX emission levels of 1.0 to
2.0 g/hp-hr (75 to 150 ppmv) can be achieved with low-emission,
dual-fuel engine designs for either new or retrofit
installations, where these designs are available from the engine
manufacturer. A 2.0 g/hp-hr controlled emission level is used in
Chapter 6 to calculate cost-effectiveness.
The effect on CO and HC emissions varies, depending upon the
engine model and manufacturer. Brake-specific fuel consumption
increases by up to 3 percent. The potential NOX emission
reductions apply only to operation in a dual-fuel mode; emission
levels are unchanged with low-emission engine designs for
100 percent diesel fuel operation.
5-84
-------
5.4 OTHER NOX CONTROL TECHNIQUES
The control techniques presented in this section are given
limited discussion due to a lack of available information or
demonstrated effectiveness in commercial applications to date.
These techniques are intake air cooling, EGR, engine derate,
water injection and water/fuel emissions, and alternate fuels.
These techniques are discussed briefly in this section.
5.4.1 Intake Air Cooling
Cooling the intake air prior to induction into the cylinder
has the potential to reduce NOX emissions. The reduced air
temperature theoretically lowers peak combustion temperatures,
thereby reducing NO., formation. Cooler intake air temperatures
Jt
also offer the potential for increased power output and improved
fuel economy.
Naturally aspirated engines induce air at ambient
temperatures. Turbocharged engines have a heat exchanger located
downstream of the turbocharger (aftercooler) that removes some of
the heat generated by compression of the intake air through the
turbocharger. In naturally aspirated engines, a separate-circuit
cooling system connected to a heat exchanger in the intake air
system would be required to cool the intake air to below ambient
temperatures. A larger, more efficient aftercooler would
potentially reduce intake air temperatures in turbocharged
engines, but substantial air cooling would require a
separate-circuit cooling system.
This control technique is used in combination with other
parametric adjustments in emission tests reported in several
references to reduce NOX emissions from both SI and CI engines.
Data were not available, however, to indicate achievable NOX
reductions using air intake cooling independently.
5.4.2 Exhaust Gas Recirculation
This control technique replaces a portion of the incoming
combustion air with exhaust gas. The exhaust gas has a low 02
content and acts as a heat sink during the combustion process,
lowering combustion temperatures and, hence, NO., formation. In
Jv
SI engines EGR may require cooling and filtering of the
5-85
-------
recirculated exhaust gases and a complex control system.77 For
CI engines, E6R results in fouled air intake systems, combustion
chamber deposits, and increased engine wear rates. 3 All
manufacturers contacted for this study indicated that this
technique is not offered for production SI and CI engines.
5.4.3 Power Output Derate
Engine derate is accomplished by reducing the fuel input to
the engine, thereby reducing power output. This reduced fuel
input results in lower combustion temperatures and pressures,
thereby reducing NOX. Emission data in Reference 5 show only
marginal brake-specific NOX reductions ranging from 0.2 to
6.2 percent. In CI engines, brake-specific NOX emissions may
actually increase at reduced power levels.
5.4.4 Water Injection
Direct water injection into 1C engines does not appear to be
a viable control technique. Internal combustion engines have a
lubricating oil film on the walls of the cylinders that minimises
mechanical wearing of reciprocating parts, and water injection
adversely impacts this oil film, accelerating engine wear. This
control technique is not available from any engine manufacturers
contacted for this report.
5.4.5 Water/Fuel Emulsions
No documentation of this control technique has been found to
suggest it has been demonstrated in stationary 1C engines. All
engine manufacturers contacted stated that water/fuel emulsions
are not an option for their engines.
5.4.6 Alternate Fuels
Coal/water slurries (CWS) and methanol have been fired in 1C
engines in limited testing to date. For CWS, several reports
include test data indicating reduced NOX emissions. Methanol
produces lower combustion temperatures than natural gas and
diesel and therefore would theoretically produce lower NOX
emissions. No data for methanol firing were found. Neither CWS
nor methanol is currently being used in any identified commercial
engine installation in the United States.
5-86
-------
5.5 REFERENCES
l. Sorge, G. W. Update on Emissions. Waukesha Engine
Division-Dresser Industries. August 1991.
2. Summers, J. C., A. C. Frost, W. B. Williamson, and
I. M. Freidel. Control of NOX/CO/HC Emissions from Natural
Gas Fueled Stationary Engines with Three-Way Catalysts,
No. 91-95.4. Report to the Air & Waste Management
Association. Allied-Signal Inc., Tulsa, OK. June 1991.
3. Letter and attachment from Shade, W. N., Ajax-Superior
Division of Cooper Industries, to Snyder, R. B., Midwest
Research Institute. March 19, 1993. Parametric adjustments
to reciprocating engines.
4. Waukesha Engine Division of Dresser Industries, Inc.,
Product Bulletin #318, Waukesha, WI. July 1991.
5. Stationary Internal Combustion Engines. Background
Information Document for Proposed New Source Performance
Standard. EPA-450/2-78-125a. U. S. Environmental
Protection Agency, Research Triangle Park, NC. July 197'9.
pp. 4-88 through 4-102.
6. Letter and attachments from Welch, R. W., Columbia Gas
System, to R. B. Snyder, Midwest Research Institute. May
19, 1992. Internal combustion engine emission control
systems.
7. Dresser-Rand Company. Exhaust Emissions and Controls--Spark
Ignited Engines. Publication No. 91-260. Prepared for the
Pipeline and Compressor Research Council. Presented at the
Reciprocating Machinery Conference. Salt Lake City.
September 23-26, 1991. Section 1, p. 12.
8. Minutes of meeting dated March 5, 1993 with representatives
of the Interstate Natural Gas Association of America, U. S.
Environmental Protection Agency, and Midwest Research
Institute. March 4, 1993. Review of draft reciprocating
engine ACT document.
9. Letter and attachment from Stachowitz, R. W., Waukesha
Engine Division of Dresser Industries, to Neuffer, W. J.,
EPA/ISB. September 4, 1992. Review of draft reciprocating
engine ACT document.
10. Letter and attachments from Dowdall, D. C., Caterpillar
Incorporated, to Snyder, R. B., Midwest Research Institute.
April 16, 1993. Effect of parametric adjustments on
reciprocating engines.
5-87
-------
11. Arthur D. Little, Inc. Evaluation of NO.. Control
Technologies for Gas-Fired Internal "Reciprocating"
Combustion Engines. Santa Barbara, CA. March 6, 1989.
38 pp.
12. Tice, J. K., and M. R. Nalim (Diesel and Gas Engineering
Company). Control of NOX Emissions in Gas Engines using
Prestratified Charge - Applications and Field Experience.
Presented at the Energy Sources Technology Conference and
Exhibition. New Orleans. January 10-14, 1988. 6 pp.
13. Urban, C. M., H. E. Dietzmann, and E. R. Fanick. Emission
Control Technology for Stationary Natural Gas Engines.
Journal of Eng. for Gas Turbines and Power. July (111):
369-374 (1989).
14. Letter and attachments from Mikkelsen, B. L., Emissions
Plus, Inc., to Snyder, R. B., Midwest Research Institute.
April 8, 1992. Prestratified charge applications for
reciprocating engines.
15. Pape and Steiner Environmental Services. Emission Tests at
Southern California Gas Company. Source Test Report
prepared for Southern California Gas Company, Los Angeles.
Report No. PS-87-1261. November 1987.
16. Emission Tests at Southern California Gas Company. Source
Test Summary prepared by South Coast Air Quality Management
District. Los Angeles. Report No. 87-0080M. December 21,
1987.
17. Emission Tests at Southern California Gas Company. Source
Test Summary prepared by South Coast Air Quality Management
District. Los Angeles. Report No. 86-0048M. April 17,
1987.
18. Emission Test at Southern California Gas Company. Source
Test Summary prepared by South Coast Air Quality Management
District. Los Angeles. Report No. 86-0058M. April 18,
1986.
19. Emission Test at Southern California Gas Company. Source
Test Summary prepared by South Coast Air Quality Management
District. Los Angeles. Report No. 97-0081M. December 9,
1987.
20. Emission Tests at Southern California Gas Company. Source
Test Summary prepared by South Coast Air Quality Management
District. Los Angeles. Report No. 87-0082M. December 9,
1987.
5-88
-------
21. Pape and Steiner Environmental Services. Emission Tests at
OXY USA. Source Test Report prepared for South Coast Air
Quality Management District. Report No. 89CST047.
March 30, 1990.
22. Western Environmental Services. Emission Tests at OXY USA.
Source Test Report prepared for OXY USA. Bakersfield, CA.
June 1988.
23. Letter and attachments from Mitchell, G., Emissions Plus
Incorporated, to Snyder, R. B., Midwest Research Institute.
March 23, 1993. Emissions data for Las Virgines PSC®
installation.
24. Ventura County Air Pollution Control District. Ventura, CA.
Emissions data base for reciprocating engines. 1986-1992.
25. Letter from Deville, D., Hanover Compressor Company, to
Mikkelsen, B. L., Emission Plus Incorporated. March 19,
1993. Emission test results for PSC® applications.
26. Burns, K. R., M. F. Collins, and R. M. Heck. Catalytic
Control of NOX Emissions From Stationary Rich-Burning
Natural Gas Engines. 83-DGP-12. The American Society of
Mechanical Engineers, New York. 1983.
27. Minutes of meeting with representatives from Emission
Control Systems, Inc., U. S. Environmental Protection
Agency, and Midwest Research Institute. April 2, 1992.
Nonselective catalytic reduction for internal combustion
engines.
28. Letter and attachments from Becguet, J., Kleenaire Division
of Nitrogen Nergas Corporation, to Snyder, R. B., Midwest
Research Institute. May 11, 1992. Catalytic controls for
internal combustion engines.
29. Letter and attachment from Herbert, K. J., Allied Signal
Incorporated, to Neuffer, W. J., EPA/ISB. September 25,
1992. Nonselective catalytic reduction system information.
30. Letter from Harris, H. L., Houston Industrial Silencing, to
Neuffer, W. J., EPA/ISB. September 17, 1992. Review of
draft reciprocating engine ACT document.
31. Letter and attachments from Harris, H. C., Houston
Industrial Silencing, to Snyder, R. B., Midwest Research
Institute. June 2, 1992. Catalytic reduction systems for
internal combustion engines.
32. Reference 11, Technical Attachment, Att. C.
5-89
-------
33. Letter and attachments from Wax, M. J., institute of Clean
Air Companies (formerly Industrial Gas Cleaning Institute),
to Neuffer, W. J., EPA/ISB. September 17, 1992. Review of
draft reciprocating engine ACT document.
34. Letter and attachments from Smith, J. C., Institute of Clean
Air Companies, to Neuffer, W. J., EPA/ISB. May 14, 1992.
Use of Catalyst Systems with stationary combustion sources.
35. Letter and attachments from Mikkelsen, B. L.f Emissions Plus
Incorporated, to Neuffer, W. J., EPA/ISB. September 11,
1992. Review of draft reciprocating engine ACT document.
36. Ballard, H. N., S. C. Hay, and W. N. Shade. An Overview of
Exhaust Emissions Regulatory Requirements and Control
Technology for Stationary Reciprocating Engines. Cooper
Industries. Springfield, OH. Presented at the Society of
Petroleum Engineers Mid-Continent Gas Symposium. Amarillo,
TX. April 13-14, 1992. 12 pp.
37. Letter and attachments from Stachowicz, R. W., Waukesha
Engine Division of Dresser Industries, Inc., to
Snyder, R. B., Midwest Research Institute. September 16,
1991. Internal combustion engines.
38. Letter and attachments from Miklos, R. A., Cooper-Bessemer
Reciprocating Products Division, to Jordan, B. C., EPA/ESD.
January 21, 1992. Internal combustion engines.
39. Letter and attachments from Dowdall, D. C., Caterpillar
Inc., to Jordan, B. C., EPS/BSD. March 25, 1992. Internal
combustion engines.
40. Letter and attachments from locco, D. E., Dresser-Rand, to
Snyder, R. B., Midwest Research Institute. October 1, 1992.
Internal combustion engines.
41. Letter and attachments from Kasel, E., Fairbanks-Morse
Engine Division, to Snyder, R. B., Midwest Research
Institute. September 9, 1991. Internal combustion engines.
42. Letter and attachments from McCormick, W. M., Cooper
Industries - Ajax Superior Division, to Snyder, R. B.,
Midwest Research Institute. September 16, 1992. Internal
combustion engines.
43. Telecon. Mayer, C. L., Waukesha Engine Division of Dresser
Industries, and Snyder, R. B., Midwest Research Institute.
April 15, 1992. Lean-burn technology for internal
combustion engines.
5-90
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44. Memorandum and attachments from Haagensen, J., Texas Air
Control Board, to Texas Air Control Board Compliance
Division. June 26, 1990. Emissions test for TACB Permit
No. C-19139.
45. Letter and attachment from McCoy, J., Tenneco, to Snyder,
R. B., Midwest Research Institute. March 11, 1993.
Emission data for lean-burn reciprocating engines.
46. Fletcher, C. C., and G. C. Hutcherson. Pilot
Study--Enhanced Emissions Monitoring for Natural Gas
Pipeline Stations. Tenneco Gas Company. Houston. August
1992. 33 pp.
47. Dietzmann, H. E., and E. R. Fanick. Parametric Control
Method Tests for In-Use Engines. Southwest Research
Institute. San Antonio, TX. Presented at the
Energy-Sources Technology Conference and Exhibition.
Dallas. February 15-20, 1987. 10 pp.
48. Fanick, E. R. Southwest Research Institute, San Antonio,
TX. Limited Parametric Study on Two Delaval Engines.
Prepared for Valero Transmission Company, San Antonio, TX.
SWRI-2219, Revised January 1989.
49. Letter from Eichamer, P. D., Exxon Chemical Company, Basic
Chemicals Group, to Snyder, R. B., Midwest Research
Institute. June 24, 1992. Emission data for reciprocating
engines.
50. Bittner, R. W. (Johnson Matthey, Wayne, PA), and
F. W. Aboujaoude (Fairbanks Morse Engine Division, Beloit,
WI). Catalytic Control of NOX, CO, and NMHC Emissions from
Stationary Diesel and Dual-Fuel Engines. Presented at the
ASME Energy Sources Technology Conference and Exhibition
Houston. January 26-30, 1992. 5 pp.
51. Benson, C., G. Chittick, and R. Wilson (Arthur D. Little,
Inc.). Selective Catalytic Reduction Technology for
Cogeneration Plants. Prepared for New England Cogeneration
Association. November 1988. 54 pp.
52. Minutes of meeting dated February 5, 1992 with
representatives of the Industrial Gas Cleaning Institute,
U. S. Environmental Protection Agency, and Midwest Research
Institute. December 18, 1991. Selective catalytic
reduction.
53. Letter and attachments from Sparks, J. S., Atlas-Steuler
Division of Atlas Minerals and Chemicals, Incorporated, to
Neuffer, W. J., EPA/ISB. August 19, 1992. Review of draft
reciprocating engine ACT document.
5-91
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54. Letter and attachments from Sparks, J. S., Atlas-Steuler
Division of Atlas Minerals and Chemicals Incorporated, to
Snyder, R. B., Midwest Research Institute. May 11, 1992.
Zeolite catalysts used in selective catalytic reduction
systems.
55. Letter from Sparks, J. S., Atlas-Steuler division of Atlas
Minerals and Chemicals Incorporated, to Snyder, R. B.,
Midwest Research Institute. March 30, 1993. SCR system
information.
56. Letter from Shade, W. N., Ajax-Superior Division of Cooper
Industries, to Neuffer, W. J., EPA/ISB. September 10, 1992.
Review of draft reciprocating engine ACT document.
57. Letter and attachments from Becquet, J. W., Kleenaire
Division of Encor Environmental Consulting and Remediation,
to Snyder, R. B., Midwest Research Institute. March 25,
1993. Selective catalytic reduction applications for
reciprocating engines.
58. Letter and attachments from Wax, M. J., Institute of Clean
Air Companies, to Snyder, R. B., Midwest Research Institute.
March 4, 1993. Selective catalytic reduction applications
for reciprocating engines.
59. Pape and Steiner Environmental Services. Emission Tests at
Southern California Gas Company. Prepared for Southern
California Gas Co., Los Angeles. Source Test Report
No. 89CST101. July 1990.
60. Scott Environmental Technologies. Emission Tests at
Consolidated Natural Gas Transmission Corporation. Prepared
for Consolidated Natural Gas Transmission Corporation,
Clarksburg, WV. Report No. SET 1314-01-1189. October 1989.
61. Southwest Research Institute. Emissions Data for DeLaval
Engine. Prepared for Valero Transmission, San Antonio, TX.
July 1990.
62. Pape and Steiner Environmental Services. Emission Tests at
Southern California Gas Company. Prepared for Southern
California Gas Company, Los Angeles. Report No. PS-88-1482.
June 1988.
63. Letter and attachments from Fisher, J., Detroit Diesel
Corporation, to Jordan, B. C., EPA/ESD. June 10, 1992. NOX
control techniques for internal combustion engines.
64. Letter and attachment from Dowdall, D. C., Caterpillar
Incorporated, to Neuffer, W. J., EPA/ISB. December 17,
1992. Review of draft reciprocating engine ACT document.
5-92
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60. Scott Environmental Technologies. Emission Tests at
Consolidated Natural Gas Transmission Corporation. Prepared
for Consolidated Natural Gas Transmission Corporation,
Clarksburg, WV. Report No. SET 1314-01-1189. October 1989.
61. Southwest Research Institute. Emissions Data for DeLaval
Engine. Prepared for Valero Transmission, San Antonio, TX.
July 1990.
62. Pape and Steiner Environmental Services. Emission Tests at
Southern California Gas Company. Prepared for Southern
California Gas Company, Los Angeles. Report No. PS-88-1482.
June 1988.
63. Letter and attachments from Fisher, J., Detroit Diesel
Corporation, to Jordan, B. C., EPA/ESD. June 10, 1992. NOX
control techniques for internal combustion engines.
64. Letter and attachment from Dowdall, D. C., Caterpillar
Incorporated, to Neuffer, W. J., EPA/ISB. December 17,
1992. Review of draft reciprocating engine ACT document.
65. Radian Corporation. Internal Combustion Engine NOX Control.
Prepared for the Gas Research Institute (Chicago) and the
Electric Power Research Institute (Palo Alto, CA).
Publication No. GS-7054. December 1990. 55 pp.
66. Letter and attachments from Waskewics, P., Power Systems
Associates, to Cassidy, M. A., C-Tec, Inc. May 30, 1991.
Emissions from diesel engines.
67. Letter from Mayer, C. L., Waukesha Engine Division of
Dresser Industries, Inc., Waukesha, WI, to Lee, L., State of
California Air Resources Board, Stationary Source Division,
Sacramento, CA. September 27, 1991.
68. Letter and attachments from Henegan, D., Norton Company, to
Snyder, R. B., Midwest Research Institute. February 4,
1992. Catalytic controls for internal combustion engines.
69. Letter and attachments from Heneghan, D., Norton Chemical
Corporation, to Neuffer, W. J., EPA/ISB. May 6, 1992.
Zeolite catalyst applications for combustion sources.
70. Letter and attachment from Snyder, R. B., Midwest Research
Institute, to Sparks, J. S., Atlas-Steuler Division of Atlas
Minerals and Chemicals, Inc. March 11, 1993. Zeolite
catalyst applications for combustion sources.
71. Facsimile. Snyder, R. B., Midwest Research Institute, to
Harris, H., Houston Industrial Silencing. April 28, 1993.
Catalytic controls for internal combustion engines.
5-93
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76. Letter and attachment from Ashenmacher, T. G., 3M
Environmental Engineering and Pollution Control, to Thomas,
J., Texas Air Control Board. June 12, 1990. Emission
testing of a dual-fuel engine at 3M.
77. Castaldini, C., Accurex Corporation. NOX Reduction
Technology for Natural Gas Industry Prime Movers. Prepared
for Gas Research Institute. Publication No. GRI-90/0215.
August 1990.
78. Reference 5. pp. 4-140 to 4-145.
5-94
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6.0 CONTROL COSTS
This chapter presents cost and cost effectiveness estimates
for the NOX control techniques discussed in Chapter 5.
Section 6.1 presents the cost evaluation methodology used to
develop capital and annual costs for these techniques.
Sections 6.2 and 6.3 present the costs and cost effectiveness for
rich-burn and lean-burn spark-ignition (SI) engine controls,
respectively. Control costs and cost effectiveness for diesel
and dual-fuel engines are given in Section 6.4. References for
the chapter are listed in Section 6.5. Summary tables for
capital and annual costs and cost effectiveness for each control
technique are included in Appendix B. All costs presented in
this chapter and Appendix B are in 1993 dollars.
6.1 COST EVALUATION METHODOLOGY
Three cost considerations are presented in this chapter:
total capital costs, total annual costs, and cost effectiveness.
The components that make up these costs and the methodology used
to determine each cost component are presented in this section.
Implementing some control techniques results in a reduction
in the engine power output caused either by altered combustion
conditions or increased backpressure on the engine. The
potential power deration, where applicable, -is identified for
each control technique in this chapter and in Chapter 5. Any
costs associated with the power reduction penalty, however,
depend upon site-specific factors (e.g., value of lost product or
capital and annual costs for equipment required to make up for
the power loss) and cannot be quantified in this document. As a
result, the cost associated with the power reduction should be
6-1
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identified on a site-specific basis and added to the costs
presented in this chapter for each control technique for which a
potential power reduction is identified. For example, if a
compressor engine is derated by 200 horsepower (hp) as a result
of installing a control technique, the owner could incur the cost
of a 200 hp motor, compressor, drive coupling, ancillary
equipment, and installation, operation, and maintenance of the
equipment to make up the power loss. For a pipeline application,
a capacity reduction of as little as 0.4 percent could require
the installation of an additional compressor engine, complete
with ancillary equipment, interconnecting piping and controls,
buildings, permitting, and potential emission offset
requirements.1
6.1.1 Capital Cost Estimation
As shown in Table 6-1, the total capital cost is the sum of
the purchased equipment costs, direct installation costs,
indirect installation costs, and contingency costs. The
purchased equipment cost (PEC) used in this chapter for each
control technique is based on cost information provided by engine
manufacturers or control system vendors. Where capital cost
estimates provided by equipment suppliers did not include
installation costs, these costs were estimated using the approach
in the EPA Office of Air Quality and Planning Standards (OAQPS)
Control Cost Manual, which recommends estimating direct
installation costs as 45 percent of PEC and indirect installation
costs as 33 percent of PEC.2 Where installation costs were
included in the capital cost estimate provided by equipment
suppliers, it was assumed that these cost estimates did not
include such items as the purchaser's engineering and project
management costs, field connections, painting, and training.
Therefore, reduced direct and indirect installation factors were
applied to the capital cost estimates provided by the supplier to
cover these costs. The direct and indirect installation factors
used in each case are defined in the appropriate sections of this
chapter. In each case a contingency factor of 20 percent was
6-2
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TABLE 6-1. TOTAL CAPITAL COST COMPONENTS AND FACTORS2
Capital cost elements
Direct costs (DC)
Purchased equipment costs (PEC):
• Control device and auxiliary equipment
• Instrumentation
• Sales taxes (3 percent of PEC)
• Freight (5 percent of PEC)
Direct installation costs (DIG):
• Foundations and supports
• Handling and erection
• Electrical
• Piping
• Insulation for ductwork
• Painting
Total direct cost (DC) = PEC + PIC
Indirect costs (1C)
Indirect installation costs (IIC):
• Engineering
• Construction and field expenses
• Contractor fees
• Start-up
• Performance test
• Model study
• Training
Contingencies (C):
• Equipment redesign and modifications
• Cost escalations
• Delays in start-up
Total indirect cost (1C) = IIC + C
TOTAL CAPITAL COST (TCC) = DC + 1C
6-3
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added to the vendor costs, as recommended in the OAQPS cost
manual, to cover contingencies as listed in Table 6-1.
6.1.2 Annual Costs
Annual costs consist of the direct operating costs of
materials and labor for maintenance, operation, utilities, and
material replacement and disposal (e.g., spent catalyst material)
and the indirect operating charges, including plant overhead,
general administration, and capital recovery charges. Table 6-2
lists these costs and includes the values used for these costs.
A brief description is provided below for each component of
the direct and indirect annual operating costs used in the cost
evaluation. Additional discussions, where necessary, are
provided in the appropriate section for each control technique.
6.1.2.1 Utilities. Utility requirements for 1C engine
control techniques are limited to electricity and/or compressed
air to power control instrumentation and auxiliary equipment and
the energy requirements for vaporization and injection of ammonia
for SCR systems. The cost for electricity and compressed air,
where required, is considered to be negligible relative to the
other operating costs. The cost for ammonia vaporization and
injection was calculated using steam for ammonia dilution and
vaporization. A cost of $6/1,000 pounds (Ib) was used for steam.
6.1.2.2 Operating and Supervisory Labor. Operating and
supervisory labor may be required for some control techniques,
depending on the complexity of the system involved and the extent
to which the control system is automated. The addition of
control equipment at remote, unmanned engine installations could
require a part- or full-time operator, plus travel time and
expenses in some cases for coverage of multiple sites. For this
cost methodology, an operating labor requirement of 2 hours (hr)
per 8-hr shift is estimated for prestratified charge and
nonselective catalytic reduction. For selective catalytic
reduction, the operator requirement is increased to 3 hours per
8-hr shift to include operation of the ammonia injection and
continuous emission monitoring systems (CEMS). For parametric
adjustment (e.g., air/fuel ratio adjustment and ignition/
6-4
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TABLE 6-2. TOTAL ANNUAL COST ELEMENTS AND FACTORS
Direct annual costs (DC)
1. Utilities:
Electricitya
Compressed aira
Natural gasb/c
Diesel fuelb'c
Steamd
2. Operating labor6
Operator labor
Supervising labor
3 . Maintenance
4. Annual compliance test
5 . Catalyst replacement
6. Catalyst disposal
$0.06/kWh
$0.16/1,000 scfm
$3.88/1,000 ft3
19,820 Btu/lb (LHV)
940 Btu/ft3 fLHV)
0.0473 lb/ft3
$0.77/gallon
18,330 Btu/lb (LHV)
7.21 Ib/gallon
$6/1,000 Ib.
$27.00 per hour
15% of operator labor
10% of purchased equipment
costs
$2,440f
$10/hp9
$15/ft3 h
Indirect annual costs (1C)1
Overhead
Property tax
Insurance
Administrative charges
Capital recovery
TOTAL ANNUAL COST
60% of maintenance cost
1% of total capital cost
1% of total capital cost
2% of total capital cost
CRF x total capital investment
DC + 1C
LHV = lower heating value
CRF = capital recovery factor
^Reference 2, Table 5.10.
^Average costs for 1990 from Reference 3.
^Fuel properties from Reference 4.
dFrom Reference 2, Table 4.5.
^Reference 5.
fReference 6, escalated at 5 percent annually.
^Reference 7.
^Reference 8.
^•Reference 2, p. 2-29.
6-5
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injection timing retard) and low-emission combustion
modification, no additional operating labor requirements are
expected over that required for current operation. The operating
labor rate, shown in Table 6-2, is estimated at $27/hr. Super-
visory labor costs are calculated as 15 percent of the annual
operating labor costs.
6.1.2.3 Maintenance. Specific maintenance costs were not
available from the control system vendors and manufacturers. The
guidelines for maintenance costs in Reference 2 suggest a
maintenance labor cost of 0.5 hour per 8 hr shift, and a
maintenance material cost equal to this labor cost. However,
this approach, using a maintenance labor cost of $34.40/hr,
results in maintenance costs that approach or exceed the PEC for
some control techniques. This approach also results in
maintenance costs that are constant for each control technique,
regardless of engine size or control system complexity. For
these reasons, the total annual maintenance cost, including labor
and materials, is calculated for continuous-duty applications to
be equal to 10 percent of the purchased equipment cost for each
control technique. For intermittent- and standby-duty
applications, the maintenance cost is prorated based on the
operating hours.
6.1.2.4 Fuel Penalty. Implementing most of the control
techniques changes the brake-specific fuel consumption of the
engine, due either to a change in combustion conditions or
increased backpressure on the engine. A fuel penalty is
assessed, where applicable, to compensate for increased fuel
consumption. Engine power output and fuel consumption rate (heat
rate) were provided by engine manufacturers.^"1^ This
information was used to establish a range of engine sizes within
each engine category (i.e., rich-burn spark-ignited [SI], lean-
burn SI, diesel, and dual-fuel) and to calculate an average heat
rate for each range, as shown in Table 6-3. For example, as
shown in Table 6-3, rich-burn SI engines up to 200 hp in size are
assigned a heat rate of 8,140 Btu/hp-hr. The fuel penalty is
assessed as a percentage of the annual fuel cost, which is
6-6
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TABLE 6-3. UNCONTROLLED NO^ EMISSION FACTORS
FOR COST EFFECTIVENESS^ CALCULATIONS
Engine
size, hp
No of
engines
Heat
rate,
Btu/hp-hr
Average
NOX emisson
factor,
g/hp-hr
Average
NOX emission
factor,
Ib/MMBtu
Weighted average for each
engine type*
NOX,
g/hp-hr
NOX,
Ib/MMBtu
RICH-BURN SI ENGINES
0-200
201-400
401-1000
1001-2000
2001-4000
4001 +
8
13
31
19
10
2
8140
7820
7540
7460
6780
6680
13.1
16.4
16.3
16.3
15
14
3.54
4.62
4.76
4.81
4.87
4.62
15.8
4.64
LEAN-BURN SI ENGINES
0-400
401-1000
1001-2000
2001-4000
4001 +
7
7
43
30
25
8760
7660
7490
7020
6660
7.9
18.6
17.8
17.2
16.5
1.99
5.35
5.23
5.40
5.46
16.8
5.13
DIESEL ENGINES
0-200
201-400
401-1000
1001-2000
2001-4000
4001 +
12
8
22
14
6
6
6740
6600
6790
6740
6710
6200
11.2
11.8
13.0
11.4
11.4
12.0
3.66
3.94
4.22
3.73
3.74
4.26
12.0
3.95
DUAL-FUEL ENGINES
700-1200
1201-2000
2001-4000
4001 +
5
3
5
4
6920
7220
6810
6150
10.0
10.7
8.4
4.9
3.18
3.26
2.72
1.75
8.5
2.72
Note: Ib/MMBtu = (g/hp-hr) x (lb/454g) x (I/Heat Rate) x (1,000,000).
aWeighted average is calculated by multiplying the average NOX emission factor by the number of engines for each
engine size and dividing by the total number of engines. For example, for dual-fuel engines, the weighted
average is calculated as:
[(5 x 10.0) + (3 x 10.7) -I- (5 x 8.4) + (4 x 4.9)]/17 = 8.5 g/hp-hr
6-7
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calculated using the assigned heat rate from Table 6-3 and the
fuel cost from Table 6-2.
6.1.2.5 Catalyst Replacement and Disposal . Most catalyst
vendors guarantee that the catalyst material will meet the
site- specified emissions reduction requirements for a period of
2 or 3 years. A catalyst life of 3 years (24,000 hr) was used in
this analysis for both selective catalytic reduction (SCR) and
nonselective catalytic reduction (NSCR) .
6.1.2.6 Overhead . An annual overhead charge of 60 percent
of the total maintenance cost was used, consistent with
guidelines in Reference 2.
6.1.2.7 Property Taxes. The property taxes were calculated
as 1 percent of the total capital cost of the control system,
consistent with guidelines in Reference 2.
6.1.2.8 Insurance . The cost of insurance was calculated as
1 percent of the total capital cost of the control system,
consistent with guidelines in Reference 2.
6.1.2.9 Administrative Charges. The administrative charges
were calculated as 2 percent of the total capital cost of the
control system, consistent with guidelines in Reference 2.
6.1.2.10 Emission Compliance Test. It is anticipated that
an emission compliance test would be required at least annually
at sites where emission limits are established and control
techniques are implemented. An annual cost for emission testing
of $2,440 is used, based on information from Reference 6,
escalated at 5 percent per year.
6.1.2.11 Capital Recovery. In this cost analysis the
capital recovery factor (CRF) is defined as:2
CRF = i (l + i)p = 0.1098
where: i » the annual interest rate, 7 percent, and
n = the equipment life, 15 years.
The CRF is used as a multiplier for the total capital cost to
calculate equal annual payments over the equipment life.
6-8
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6.1.3 Cost Effectiveness
Cost effectiveness, in $/ton of NOX removed, is calculated
for each control technique by dividing the total annual cost by
the annual tons of NOX removed. Uncontrolled emission factors
were developed using information provided by engine
manufacturers.9"15 This information was used to establish a
range of engine sizes within each engine category
(i.e., rich-burn SI, lean-burn SI, diesel, and dual-fuel) and to
calculate an average uncontrolled emission factor for each range,
as shown in Table 6-3. To simplify NOX emission calculations, a
single emission factor was developed for each engine category,
calculated as the weighted average for all engines in each
category. For example, as shown in Table 6-3, rich-burn SI
engines are assigned a NOX emission factor of 15.8 grams per
horsepower-hour (g/hp-hr) (4.64 pounds per million British
thermal units [Ib/MMBtu]).
In general, cost effectiveness is highest for small engines
because capital costs, on a per-horsepower basis, are highest for
these engines while the per-horsepower NOX removal rate remains
constant regardless of engine size. Cost effectiveness also
increases as operating hours decrease because capital costs
remain unchanged while annual NOX reductions decrease with
operating hours.
6.2 CONTROL COSTS FOR RICH-BURN SI ENGINES
The applicable control techniques for rich-burn SI engines
are air/fuel ratio (A/F) adjustment, ignition timing retard, a
combination of A/F adjustment and ignition timing retard,
prestratified charge (PSC®), NSCR, and low-emission combustion.
The costs for these control techniques as applied to rich-burn SI
engines are presented in this section.
6.2.1 Control Costs for A/F Adjustment
6.2.1.1 Capital Costs. The capital costs for A/F
adjustment are based on installing an automatic A/F ratio
controller on the engine to achieve sustained NO., emission
Jt
reductions with changes in operating loads and ambient conditions
6-9
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and to minimize engine misfire with these changes. The A/F
controls typically consist of an oxygen (02) sensor installed in
the exhaust, which directs a signal to a regulator that modifies
fuel or air delivery pressure. For carbureted, naturally
aspirated engines, the control system adjusts a bypass around the
carburetor or a pressure regulator. For turbocharged engines,
the control adjusts the wastegate valve to bypass exhaust around
the turbocharger turbine.
Some engine manufacturers provide these A/F controls as
standard equipment on their engines, especially in newer engine
designs, and A/F can be adjusted on these engines with no
requirement for purchased equipment. In this case, the total
capital cost for A/F control is expected to be less than $4,000
for all engines, regardless of size. This cost includes
approximately 16 labor hours, associated direct/indirect and
contingency factors to perform the adjustments on the engine, and
an emission compliance test.
For engines that are not equipped with provisions for
automatic A/F adjustment, the capital costs for hardware and
software are estimated by engine manufacturers to range from
approximately $7,000 to $18,000,16'17 A cost of $7,000 was used
for engines up to 1,000 hp, $10,000 for engines from 1,001 hp to
2,500 hp, and $15,000 for engines above 2,500 hp. Sales tax and
freight charges total 8 percent of the PEC. These costs are for
retrofit kits provided by the engine manufacturer, so the direct
and indirect installation factors are reduced from 45 and 33 to
15 and 20 percent of the PEC, respectively. These factors are
chosen because this control system mounts directly on the engine
and is pre-engineered, thereby reducing the engineering and
installation efforts required by the purchaser. The contingency
factor is 20 percent of PEC.
Based on the above methodology, the total capital costs for
A/F adjustment for rich-burn engines are:
Engines to 1,000 hp: $11,400
6-10
-------
Engines 1,001 to 2,500 hp: $16,300
Engines over 2,500 hp: $24,500
These total capital costs are presented in Figure 6-1.
6.2.1.2 Annual Costs. The anticipated annual costs
associated with A/F adjustment include an increase in maintenance
due to the addition of the automatic A/F system, an increase in
brake-specific fuel consumption (BSFC), emission compliance
testing, and capital recovery. The increased maintenance cost is
estimated as 10 percent of the PEC, plus an overhead cost equal
to 60 percent of the maintenance cost. Based on information
presented in Chapter 5, a fuel penalty of 5 percent is assessed.
Taxes, insurance, and administrative costs are charged as shown
in Table 6-2. The cost of a compliance test is estimated at
$2,440. The capital recovery is calculated as discussed in
Section 6.1.2.11.
Based on the above methodology, the total annual costs for
A/F adjustment for rich-burn engines are presented in Figure 6-1.
As Figure 6-1 shows, the costs are essentially linear and can be
approximated using the following equations:
Operating hours Total annual cost
8,000 $6,340 + ($11.4 x hp)
6,000 $5,790 + ($8.70 x hp)
2,000 $4,710 + ($3.10 x hp)
500 $4,300 + ($1.00 x hp)
For an 80 hp engine, the total annual costs range from $4,290 for
500 hr/yr to $6,340 for 8,000 hr/yr. For an 8,000 hp engine, the
total annual costs range from $11,800 for 500 hr/yr to $96,700
for 8,000 hr/yr.
6.2.1.3 Cost Effectiveness. As discussed in Chapter 5, the
expected range of NO., reduction for A/F adjustment for rich-burn
Jv
engines is 10 to 40 percent, and the cost effectiveness varies
according to the actual site-specific NO,, reduction. The cost
J\,
effectiveness presented in this section is calculated using a NOY
Jv
6-11
-------
1
POWER OUTPUT, HP
BOW
3X0 4000 5000
POWER OUTPUT, HP
9000-
8000- V-
7DOO-
6000-
5000-
4000-
3000-
2000-
1000-
0
Cost •flKOWwcs Catfd on 20% NOi r«duc»on
.V
1000
2)00
3000 4000 5000
POWER OUTPUT, HP
6000
7000
» 000 HOURS
•.000 HOURS
2.000 HOURS
500 HOURS
8000
Figure 6-1. Total capital and annual costs and cost
effectiveness for A/F adjustment in rich-burn engines,
based on installation of an automatic A/F adjustment
system and controls.
6-12
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reduction efficiency of 20 percent. For engine installations
already equipped with automatic A/F control, no additional
equipment purchase is necessary, and cost effectiveness is
estimated to be less than $l,000/ton for all but the smallest
engines operating in stand-by applications.
For those engines that require installation of automatic A/F
control equipment, the cost effectiveness is presented in
Figure 6-1.
For continuous-duty engines, the cost effectiveness for A/F
adjustment in rich-burn engines is over $2,800/ton for engines
less than 100 hp but decreases rapidly as engine size increases.
For engines above 1,000 hp, the cost-effectiveness curve is
relatively flat at approximately $600/ton or less. A similar
cost-effectiveness trend applies to engines that operate less
than 8,000 hr/yr, but the cost effectiveness increases to a high
of $31,000/ton for the smallest engines and decreases to
approximately $3,000/ton or less for engines above 1,000 hp
operating 500 hr/yr. The cost-effectiveness range from $10,000
to $31,000 per ton is not shown on the plot in Figure 6-1 in
order to more clearly present the range of $0 to $10,000 per ton.
6.2.2 Control Costs for Ignition Timing Retard
6.2.2.1 Capital Costs. Effective and sustained NOX
reduction with changes in engine load and ambient conditions
requires that the engine be fitted with an electronic ignition
control system to automatically adjust the ignition timing. This
ignition system is standard equipment on some engines, and in
this case no purchased equipment is required. For this case,
capital costs are expected to be approximately $4,000 or less to
cover the cost of labor (16 hr) for the initial adjustment by the
operator and subsequent emission testing.
For those engines not equipped with an electronic ignition
system, the cost for the ignition system is estimated for low-
speed, large-bore engines to be $10,000, plus $5,000 for the
electronic control system.18 This cost varies according to
engine size and the number of power cylinders, and for this study
the PEC for an electronic ignition system is estimated to be:
6-13
-------
Engines to 1,000 hp: $ 7,500
Engines 1,001 to 2,500 hp: $10,000
Engines above 2,500 hp: $15,000
Sales taxes and freight are added as 8 percent of the PEC. As is
the case for A/F adjustment, direct and indirect installation
activities are expected to be relatively straightforward, as this
system is offered as a fully engineered package from the
manufacturer and mounts directly on the engine. For these
reasons, direct and indirect installation factors of 15 and
20 percent, respectively, of the PEC are used. The contingency
factor is 20 percent of the PEC.
The total capital costs for ignition timing retard using
this methodology are:
Engines to 1,000 hp: $12,200
Engines 1,001 to 2,500 hp: $16,300
Engines over 2,500 hp: $24,500
These costs are shown in Figure 6-2.
6.2.2.2 Annual Costs. The anticipated annual costs
associated with ignition timing retard are an increase in
maintenance due to the addition of the electronic ignition
control system, an increase in BSFC, emission compliance testing,
and capital recovery. The increased maintenance cost is
estimated as 10 percent of the PEC, plus an overhead cost equal
to 60 percent of the maintenance cost. Based on information
presented in Chapter 5, a fuel penalty of 4 percent is assessed.
Taxes, insurance, and administrative costs are charged as shown
in Table 6-2, and the compliance test cost is $2,440. The
capital recovery is calculated as discussed in Section 6.1.2.11.
Based on the above methodology, the total annual costs for
ignition timing retard for rich-burn engines are presented in
Figure 6-2. As this figure shows, the costs are essentially
linear and can be approximated using the following equations:
6-14
-------
s
8
C/3
R
g
i.
5
|5
3O
— 25-
S 9f\.
-^J
POWER OUTPUT. HP
aooo
1000
2000
3000 4000 5000
POWER OUTPUT. HP
60OO
7000
8000
3000 4000 50DO
POWER OUTPUT, HP
Figure 6-2. Total capital and annual costs and cost
effectiveness for ignition timing retard in rich-burn engines,
based on installation of an electronic ignition system.
6-15
-------
Operating hours Total annual cost
8,000 $6,300 + ($9.30 x hp)
6,000 $5,790 + ($7.10 x hp)
2,000 $4,770 + ($2.50 x hp)
500 $4,390 + ($0.85 x hp)
For an 80 hp engine, the total annual costs range from $4,400 for
500 hr/yr to $6,340 for 8,000 hr/yr. For an 8,000 hp engine, the
total annual costs range from $10,700 for 500 hr/yr to $79,800
for 8,000 hr/yr.
6.2.2.3 Cost Effectiveness. As discussed in Chapter 5, the
expected range of NOX reduction for ignition timing retard for
rich-burn engines is 0 to 40 percent, and the cost effectiveness
will vary according to the actual site-specific NOX reduction.
The cost effectiveness presented in this section is calculated
using a NOX reduction efficiency of 20 percent. For engine
installations already equipped with an electronic ignition
control system, no additional equipment purchase is necessary,
and the cost effectiveness is estimated to be less than
$l,000/ton for all but the smallest engines operating in stand-by
applications.
For those engines which require installation of an
electronic ignition system, the cost effectiveness is presented
in Figure 6-2. For continuous-duty engines, the cost
effectiveness for ignition timing retard in rich-burn engines is
over $2,800/ton for engines less than 100 hp, but decreases
rapidly as engine size increases. For engines above 1,000 hp,
the cost-effectiveness curve is relatively flat at approximately
$600/ton or less. A similar cost-effectiveness trend applies to
engines that operate less than 8,000 hours per year, but the cost
effectiveness increases to a high of over $31,000/ton for the
smallest engines operating 500 hours annually, decreasing to
approximately $3,000/ton or less for engines above 1,000 hp
operating 500 hours annually. The cost-effectiveness range from
6-16
-------
$10,000 to $31,000 per ton is not shown on the plot in Figure 6-2
in order to more clearly present the range of $0 to $10,000 per
ton.
6.2.3 Control Costs For Combination of A/F Adjustment and
Ignition Timing Retard
6.2.3.1 Capital Costs. The capital costs for a combination
of A/F adjustment and ignition timing retard are based on
installing an automatic A/F ratio controller and an electronic
ignition system on the engine. Some engines include these
systems and controls as standard equipment, especially newer
engine designs, and no additional equipment is required for these
engines. In this case, capital costs are expected to be
approximately $4,000 or less. This cost includes approximately
25 labor hours and associated direct/indirect and contingency
factors to perform the adjustments on the engine and an emission
compliance test.
For engines that require the installation of A/F control and
electronic ignition systems, the capital costs are estimated to
be equal to the sum of the costs for each system. A combined PEC
of $14,500 is used for engines up to 1,000 hp; $20,000 for
1,001 hp to 2,500 hp engines; and $30,000 for engines above
2,500 hp. Sales taxes and freight are added as 8 percent of the
PEC. Because these systems are available from engine
manufacturers as fully engineered kits, direct and indirect labor
factors for installation are estimated at 15 and 20 percent,
respectively, of the combined PEC. These factors are chosen
because this control system mounts directly on the engine and is
pre-engineered, thereby reducing the engineering and installation
efforts required by the purchaser. The contingency factor is
20 percent of the PEC.
Based on the above methodology, the total capital costs for
the combustion of A/F adjustment and ignition timing retard for
rich-burn engines are:
6-17
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Engines to 1,000 hp: $23,600
Engines 1,001 to 2,500 hp: $32,600
Engines over 2,500 hp: $48,900
These capital costs are presented in Figure 6-3.
6.2.3.2 Annual Costa. The anticipated annual costs
associated with the combination of A/F adjustment and ignition
timing retard include an increase in maintenance due to the
addition of the A/F adjustment and electronic ignition control
systems, an increase in BSFC, emission compliance testing, and
capital recovery. The increased maintenance cost is estimated as
10 percent of the PEC, plus an overhead cost equal to 60 percent
of the maintenance cost. Based on information presented in
Chapter 5, a fuel penalty of 7 percent is assessed. Taxes,
insurance, and administrative costs are charged as shown in
Table 6-2, and the emission test cost is $2,440. The capital
recovery is calculated as discussed in Section 6.1.2.11.
Based on the above methodology, the total annual costs for
the combination of A/F adjustment and ignition timing retard for
rich-burn engines is presented in Figure 6-3. As Figure 6-3
shows, the costs are essentially linear and can be approximated
using the following equations:
Operating hours Total annual cost
8,000 $9,770 + ($16.3 x hp)
6,000 $8,830 + ($12.4 x hp)
2,000 $6,940 + ($4.50 x hp)
500 $6,230 + ($1.60 x hp)
For an 80 hp engine, the total annual costs range from $6,220 for
500 hr/yr to $9,800 for 8,000 hr/yr. For an 8,000 hp engine, the
total annual costs range from $17,800 for 500 hr/yr to $138,000
for 8,000 hr/yr.
6.2.3.3 Cost Effectiveness. As discussed in Chapter 5, the
expected range of NOX reduction for the combination of A/F
adjustment and ignition retard for rich-burn engines is 10 to
6-18
-------
rt 50-
8
K-~ UT
J | 30-
1
P TO
""1
1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
6.000 HOURS
2.000 HOURS
500 HOURS
3000 4000 5000
POWER OUTPUT. HP
4000
powen OUTPUT HP
Figure 6-3. Total capital and annual costs and cost
effectiveness for A/F adjustment and ignition timing
retard in rich-burn engines, based on installation of
automatic A/F adjustment system and controls and
an electronic ignition system.
6-19
-------
40 percent, and the cost effectiveness varies according to the
actual site-specific NOX reduction. The cost effectiveness
presented in this section is calculated using a NOX reduction
efficiency of 30 percent. For engine installations already
equipped with both automatic A/F and electronic ignition control
systems, no additional equipment purchase is necessary, and the
cost effectiveness is estimated to be less than $l,000/ton for
all but the smallest engines operating in stand-by applications.
For those engines equipped with provisions for one but not both
control systems, the second control system must be purchased and
installed. The cost effectiveness in this case is approximately
the same as that shown in Figure 6-1 or 6-2 for either control
used independently.
For installations where both control systems are added to
the engine, the cost effectiveness is presented in Figure 6-3.
For continuous-duty engines, the cost effectiveness for the
combination of A/F adjustment and ignition timing retard in rich-
burn engines is approximately $3,000/ton for engines less than
100 hp but decreases rapidly as engine size increases. For
engines above 1,000 hp, the cost-effectiveness curve is
relatively flat at less than $l,000/ton, decreasing slightly with
increasing engine size. A similar cost-effectiveness trend
applies to engines that operate less than 8,000 hr/yr, but the
cost effectiveness increases to a high of $30,000/ton for the
smallest engines operating 500 hr/yr and decreases to
approximately $3,000/ton or less for engines above 1,000 hp
operating 500 hr/yr. The cost-effectiveness range from $10,000
to $31,000 per ton is not shown on the plot in Figure 6-3 in
order to more clearly present the range of $0 to $10,000 per ton.
6.2.4 Control Costs for Prestratified Charge (PSC®)
As discussed in Section 5.1.3, a PSC® system can be
installed on carbureted, four-cycle engines. This control
technique can be applied with or without the addition of a
turbocharger to naturally aspirated engines or modification of
the existing turbocharger on turbocharged engines. The
turbocharger upgrade/addition is typically performed to minimize
6-20
-------
or eliminate the power output deration associated with PSC®. The
costs for PSC® are presented with and without the cost for
turbocharger upgrade/addition.
6.2.4.1 Capital Costa. Purchased equipment cost estimates
were provided for a limited number of candidate engines by the
licensed PSC® vendor.19 The costs provided include typical
installation costs, based on the vendor's experience. These
costs are approximate and vary according to site-specific factors
such as engine model and number of cylinders, hardware and
software modifications required for the turbocharger,
complexities of control and shutdown devices, and field
installation requirements.19 A control system cost of $7,700 was
added to the estimated PSC® system cost, which is the average of
the control costs housed in a weatherproof enclosure versus a
National Electrical Manufacturers Association Class 7 (NEMA 7)
enclosure.19 The costs, calculated on a per-horsepower basis,
are presented in Figure 6-4 and represent the PEC for PSC®,
including controls and installation by the vendor. The costs for
engines larger than 1,200 hp were extrapolated because data were
not available for PSC® installated on larger engines.
The total capital costs were calculated by multiplying the
PEC presented in Figure 6-4 by 1.08 to include sales taxes and
freight, and by direct and indirect installation factors of 15
and 20 percent, respectively, for installations without
turbocharger modifications. For installations with turbocharger
modifications, the direct installation factor is increased to
25 percent. A 20 percent contingency factor is included.
Based on the above methodology, the total capital costs for
PSC®, with and without turbocharger modification/addition, are
presented in Figures 6-5 and 6-6, respectively. The costs for
engines larger than 1,200 hp were extrapolated because estimates
were not available for these engine sizes. For PSC®
installations without turbocharger modification/addition, the
total capital costs begin at approximately $20,000 for 100 hp
engines and rise to over $55,000 for engines at approximately 800
to 1,000 hp. The cost estimates provided showed that capital
6-21
-------
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ij
0.
X
H
g
fM
00
o
(N
dH/$ '1SO3
•H
4J
CD
§s
sff
(0
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CO
•8
OQ
nS
u
4J
o-d
4J
c
8
or
c:
"O ^J
3 nJ
5 u S^c
« -S°-2
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iJ.5 e
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0)
CD
(0
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6-22
-------
1000
2000
3000 4*0 5000
POWER OUTPUT. HP
6000
7000
8000
1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8.000 HOURS
6.000 HOURS
2.000 HOURS
500 HOURS
1000
POWER OUTPUT. HP
8000
Figure 6-5. Total capital and annual costs and cost
effectiveness for PSC® in rich-burn engines, without
turbocharger installation or modification.
6-23
-------
3000 4000 5000
POWER OUTPUT. HP
8000
8.000 HOURS
6.000 HOURS
2.000 HOURS
500 HOURS
1000
2000
3000 4000 SOOO
POWER OUTPUT. HP
6000
7000
10000
son
POWER OUTPUT. HP
Figure 6-6. Total capital and annual costs and cost
effectiveness for PSC* in rich-burn engines, with
turbocharger installation or modification.
6-24
-------
costs began to level off for engines in the range of 1,000 to
1,200 hp, and above 1,200 hp the costs were extrapolated
linearly, resulting in an estimated total capital cost for an
8,000 hp engine of $87,000.
The available cost estimates for turbocharger modifications
were limited to only five engines. Because the extent of engine
modifications required to install or modify a turbocharger can
vary widely for different engine models, the total capital costs
for PSC® installations that include turbocharger modifications
may vary widely from the costs shown in Figure 6-6. The capital
costs curve for PSC® installations that include turbocharger
modification/addition include the costs described above plus the
capital costs for the turbocharger rework. The costs begin at
approximately $28,000 for engines rated at 100 hp or less and
climb steeply to over $130,000 for engines rated at 800 to
1,000 hp. The cost estimates provided show that capital costs
began to level off for engines in the range of 1,000 to 1,200 hp,
and above 1,200 hp the costs were extrapolated linearly,
resulting in an estimated total capital cost for an 8,000 hp
engine of $215,000.
6.2.4.2 Annual Costs. The annual costs associated with
PSC® include operating and supervisory labor, maintenance and
overhead, fuel penalty, taxes, insurance, administrative costs,
and capital recovery. No power reduction penalty is assessed,
consistent with Section 6.1. However, implementing PSC® results
in a potential power reduction of up to 20 percent, according to
the vendor, and any penalty associated with the potential power
reduction is an additional cost that should be considered on a
case-by-case basis.
Operating labor requirements are estimated to be 2 hr per
8-hr shift, and supervisory labor is calculated as 15 percent of
operating labor. The increased maintenance cost is estimated as
10 percent of the PEC, plus an overhead cost equal to 60 percent
of the maintenance cost. Based on information presented in
Chapter 5, a fuel penalty of 2 percent is assessed. Taxes,
insurance, and administrative costs are charged as shown in
6-25
-------
Table 6-2. An emission test cost of $2,440 is included. The
capital recovery is calculated as discussed in Section 6.1.2.11.
The total annual costs for PSC®, with and without
turbocharger modification/addition, are presented in Figures 6-5
and 6-6, respectively. For continuous-duty PSC* installations
without turbocharger modification/addition, the total annual
costs are approximately $70,000 for 100 hp engines and rise to
over $80,000 for engines at approximately 800 to 1,000 hp. Above
1,200 hp, the costs are extrapolated and increase linearly with
engine size, from an estimated total annual cost of $85,000 for a
1,200 hp engine to $120,000 for an 8,000 hp engine. The
additional costs associated with PSC® installations with
turbocharger modification/addition increase the total annual
costs for continuous-duty applications to over $70,000 for the
smallest engines, rising to approximately $100,000 for 1,200 hp
engines. The annual costs for engines above 1,200 hp are
estimated to increase linearly with engine size and total
$150,000 for an 8,000 hp engine.
6.2.4.3 Cost Effectiveness. As discussed in Chapter 5, the
achievable controlled NOX emission level for PSC® is 2 g/hp-hr or
less. The cost effectiveness presented in this section is
calculated using a controlled NOX emission level of 2 g/hp-hr.
For PSC® installations that do not include the addition or
modification of a turbocharger, the cost effectiveness is
presented in Figure 6-5. For continuous-duty engines
(8,000 hr/yr), the cost effectiveness is approximately $7,700/ton
for engines rated at 100 hp or less and decreases rapidly with
increasing engine size to approximately $700/ton for a 1,000 hp
engine. The cost effectiveness is relatively constant for
engines rated above 1,000 hp and is less than $600/ton. For
engines operating less than 8,000 hr/yr, cost effectiveness
increases with decreasing operating hours. The increase is
relatively small for larger engines but increases rapidly for
smaller engines, especially engines less than 1,000 hp. The cost
effectiveness for these smaller engines operating 6,000 hr/yr or
less ranges from approximately $400 to over $15,000/ton,
6-26
-------
increasing as engine size and annual operating hours decrease.
The cost-effectiveness range from $10,000 to $15,000 per ton is
not shown on the plot in Figure 6-5 in order to more clearly
present the range of $0 to $10,000 per ton.
For PSC® installations that include turbocharger
modification/addition, cost effectiveness is presented in
Figure 6-6. The cost-effectiveness figures are higher than those
shown in Figure 6-5 due to the higher total annual costs
associated with the turbocharger. The increase in cost
effectiveness is relatively small: less than $300/ton for
continuous-duty engines, increasing to a maximum of $2,000/ton
for the smallest engine operating 500 hr/yr. The cost
effectiveness for an 80 hp engine operating 500 hr/yr is
$17,400/ton. The cost-effectiveness range above $10,000/ton is
not shown on the plot in Figure 6-6 in order to more clearly
present the range of $0 to $10,000 per ton.
6.2.5 Control Costs for Nonselective Catalytic Reduction (NSCR)
6.2.5.1 Capital Costs. The PEC for NSCR includes the cost
of the catalyst system and an automatic A/F controller. These
costs are estimated at $15/hp for the catalyst and $6,000 for the
A/F controller.7'20 Sales taxes and freight are included as
8 percent of the PEC. The PEC is multiplied by factors of 45,
33, and 20 percent, respectively, for direct and indirect
installation costs and contingencies. Using this methodology,
the total capital costs for NSCR are presented in Figure 6-7.
The costs are essentially linear and can be estimated by the
following formula:
Total capital cost = $12,100 + ($30.1 x hp)
The total capital costs range from $14,800 for an 80 hp engine to
$253,000 for an 8,000 hp engine.
6.2.5.2 Annual Costs. The annual costs associated with
NSCR include operating and supervisory labor, maintenance and
overhead, fuel penalty, catalyst cleaning and replacement, taxes,
insurance, administrative costs, emission compliance testing, and
6-27
-------
1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
250
200-
• 150-
100-
50-'
1000
2000
3000 4OOO 5000
POWER OUTPUT. HP
8.000 HOURS
6.000 HOURS
2.000 HOURS
$00 HOURS
8000
3dOO 4000 5000
POWER OUTPUT.*
GOOD
7000
8000
Figure 6-7. Total capital and annual costs and cost
effectiveness for nonselective catalytic reduction
for rich-burn engines.
6-28
-------
capital recovery. No power reduction penalty is assessed,
consistent with Section 6.1. The expected power reduction
resulting from a backpressure of 4 inches of water column (in.
w.c.) caused by the catalyst system is expected to be l percent
for naturally aspirated engines and 2 percent for turbocharged
engines. Any penalty associated with the potential power
reduction is an additional cost that should be considered on a
case-by-case basis.
Operating labor requirements are estimated to be 2 hr per
8-hr shift, and supervisory labor is calculated as 15 percent of
operating labor. Maintenance costs are calculated as 10 percent
of the PEC, plus an overhead cost equal to 60 percent of the
maintenance cost. A fuel penalty of 5 percent is assessed.
Catalyst cleaning is scheduled every 12,000 hr, and a
catalyst life of 3 yr (24,000 hr) is used in this methodology
consistent with the guaranteed period available from most
catalyst vendors. The cost of cleaning is estimated at $0.75/hp
plus 10 percent for freight and is based on shipping the catalyst
to an offsite facility for cleaning.20 Based on this schedule,
the annual cost for catalyst cleaning is calculated as $0.25/hp
plus 10 percent for freight for continuous-duty applications
(8,000 hr). The catalyst replacement cost is estimated to be
rj
$10/hp. The annual cost for catalyst replacement is calculated
to be $3.67/hp plus 10 percent for freight for continuous-duty
applications. No disposal cost was assessed for NSCR
applications because precious metal catalysts are most commonly
used in NSCR systems, and most catalyst vendors offer a credit
for return of spent catalyst reactors of $0.80/hp toward the
purchase of new catalyst. For this methodology, the credit was
not considered because it could not be confirmed that all
catalyst vendors offer this credit.
Plant overhead, taxes, insurance, and administrative costs
are calculated as described in Section 6.1, and an emission test
cost of $2,440 is included. The capital recovery is calculated
as discussed in Section 6.1.2.11.
6-29
-------
The resultant total annual costs for NSCR are presented in
Figure 6-7 and can be estimated using the following equations:
Operating hours Total annual cost
8,000 $68,300 + ($22.0 x hp)
6,000 $52,300 + ($17.7 x hp)
2,000 $20,200 + ($8.9 x hp)
500 $8,260 + ($5.6 x hp)
For an 80 hp engine, the total annual costs range from $8,700 for
500 hr/yr to $69,300 for 8,000 hr/yr. For an 8,000 hp engine,
the total annual costs range from $53,100 for 500 hr/yr to
$244,000 for 8,000 hr/yr.
6.2.5.3 Cost Effectiveness. As discussed in Chapter 5, the
potential NOX emission reduction using NSCR ranges to a maximum
of 98 percent. The cost effectiveness presented in this section
is calculated using a 90 percent NOX emission reduction,
consistent with most of the emissions data presented in
Chapter 5.
The cost effectiveness is presented in Figure 6-7. For
continuous-duty engines, the cost effectiveness for NSCR
approaches $7,000/ton for engines less than 100 hp but decreases
rapidly for larger engines. For engines above 1,000 hp, the
cost-effectiveness curve is relatively flat at $800/ton or less,
decreasing slightly with increasing engine size. A similar cost-
effectiveness trend applies to engines that operate less than
8,000 hr/yr, but the cost effectiveness increases to a high of
over $13,000/ton for the smallest engines operating 500 hr/yr and
decreases to approximately $l,700/ton or less for engines above
1,000 hp operating 500 hr/yr. The cost-effectiveness range from
$10,000 to $14,000 per ton is not shown on the plot in Figure 6-7
in order to more clearly present the range of $0 to $10,000 per
ton.
6.2.6 Control Costs for Conversion to Low-Emission Combustion
The costs presented in this section reflect the cost to
retrofit an existing engine to low-emission combustion. Because
6-30
-------
the hardware requirements, and therefore the installation
requirements, are similar for either rich- or lean-burn engines,
the capital costs presented in this section apply to either
engine type. For new engine installations, the costs would be
considerably less than those presented here. The capital cost
premium for new, low-emission, medium-speed engines is estimated
by one manufacturer to range from approximately $11 to $15 per hp
for one line of engines rated at 100 to 700 hp. For another
engine line rated at 800 to 2,700 hp, the premium ranges from
approximately $10 to $33 per hp.1^ Another medium-speed engine
manufacturer estimated that the incremental cost for low-emission
engines is approximately 5 percent over that of conventional
engines.21 Similar new-equipment costs were not available for
low-speed engines.
The hardware and labor requirements to retrofit low-emission
combustion to an existing engine are similar in scope to a major
engine overhaul. If the low-emission combustion retrofit is
scheduled to coincide with a scheduled major engine overhaul, the
capital costs and cost effectiveness figures will be less than
those shown in this section. One SI engine manufacturer
estimates that retrofit to low-emission combustion, performed in
conjunction with a major overhaul on medium-speed SI engines
(approximately 800 to 2,700 hp) results in a reduction in cost
effectiveness of approximately $40 to $50 per ton of NOX.16
6.2.6.1 Capital Costs. Cost estimates from three engine
manufacturers were used to develop the capital costs for the
hardware required to retrofit existing engines to low-emission
combustion.^'^/16 ^ analysis of these costs showed that the
costs for medium-speed, large-bore engines, provided by two
manufacturers, is considerably less than those for low-speed
large-bore engines provided by the third manufacturer. For this
reason, the costs are presented separately for low- and medium-
speed engines.
The hardware costs for medium-speed engines, ranging in size
from 100 to 2,700 hp, are presented in Figure 6-8. The costs,
although scattered, are approximated using the line plotted on
6-31
-------
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en
0
111
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IO
(spuBsnoiii)
$ 1SOO
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6-32
-------
this figure. The equation of this line results in a capital cost
for the retrofit hardware for medium-speed engines of:
Medium-speed engine hardware cost = $10,800 + ($81.4 x hp)
Similar costs for low-speed engines, ranging in size from 200 to
11,000 hp, are presented in Figure 6-9. Again, the costs,
although scattered, are approximated by the line plotted on this
figure. The equation of the line gives a capital cost for the
retrofit hardware for low-speed engines of:
Low-speed engine hardware cost = $140,000 + ($155 x hp)
These equations were used to estimate the hardware costs for
low-emission retrofits.
The increased air flows required for low-emission combustion
typically require purchase of new inlet air filtration and
ductwork, exhaust silencers and ductwork, and aerial coolers.
The cost of this equipment is estimated to be 30 percent of the
hardware costs.1 The PEC is therefore calculated as 1.3 times
the hardware cost.
Direct and indirect installation factors are calculated as
25 and 20 percent of the PEC, respectively. The contingency
factor is 20 percent. Adding sales taxes and freight yields
total capital costs as presented in Figures 6-10 and 6-11 for
medium-speed and low-speed engines, respectively. The costs are
linear and can be estimated using the equations listed below:
Medium-speed engines:
Total capital costs - $24,300 + ($183 x hp)
Low-speed engines:
Total capital costs = $315,000 + ($350 x hp)
The total capital costs for medium-speed engines range from
$38,900 for an 80 hp engine to $757,000 for a 4,000 hp engine.
The total capital costs for low-speed engines are considerably
6-33
-------
I
o
CM
$ isoo
6-34
-------
80O
700-
600-
•5? 500-
400-
— 300- •
200- '
100- •
500
1500 2000 2500
POWER OUTPUT, HP
3000
3500
4000
500
1500 2000 2500
POWER OUTPUT. HP
3000
3500
4000
— - 7 " Q"T' —u~'"" '—'
500
1000
150020002500
TOWER OUTPUT HP
3000
3500
4000
Figure 6-10. Total capital and annual costs and cost
effectiveness for retrofit to low-emission .combustion
for medium-speed engines.
6-35
-------
1000
2000
3000 4000 5000
POWER OUTPUT, HP
6000
7000
8000
8.000 HOURS
(.000 HOURS
2.000 HOURS
SOD HOURS
3000 4000 5030
POWER OUTPUT, HP
DO
8.000 HOURS
6.000 HOURS
2.000 HOURS
500 HOURS
BaMd on 110 o»«>*» cenvoM NOi «rm»en IM<
3000 4000 5000
POWER OUTPUT. HP
Figure 6-11. Total capital and annual costs and cost
effectiveness for retrofit to low-emission combustion
for low-speed engines.
6-36
-------
higher, ranging from $343,000 for an 80 hp engine to $3,100,000
for a 8,000 hp engine. Because retrofit requirements are highly
variable, depending upon the engine model and installation-
specific factors, the actual costs for low-emission engine
conversion may vary considerably from those calculated using the
equations shown above.
6.2.6.2 Annual Costs. The annual costs associated with
low-emission combustion include maintenance and overhead, fuel
consumption, taxes, insurance, administrative costs, emission
compliance testing, and capital recovery. No power reduction
results from low-emission combustion; in fact, the addition of
the turbocharger in some cases may increase the power output of
engines that were previously naturally aspirated.
No increase in operating labor requirements is expected with
low-emission combustion engines. Maintenance activities
increase, however, due to potential decreased spark plug life,
precombustion chamber admission valves maintenance requirements,
and increased turbocharger inspections. Maintenance costs are
calculated as 10 percent of the PEC, plus an overhead cost equal
to 60 percent of the maintenance cost. Based on a comparison of
heat rates for rich-burn engines and low-emission engines, a
1 percent fuel credit is used in the annual cost calculations.
Plant overhead, taxes, insurance, and administrative costs
are calculated as described in Section 6.1. A cost of $2,440 is
added for emission testing. The capital recovery is calculated
as discussed in Section 6.1.2.11.
The resultant total annual costs for medium- and low-speed
engines for low-emission combustion are presented in Figures 6-10
and 6-11, respectively. The costs are essentially linear and can
be approximated by the following equations:
6-37
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Medium-speed engines:
Operating hours Total annual cost
8,000 $8,100 + ($42.2 x hp)
6,000 $7,600 + ($38.5 x hp)
2,000 $6,600 + ($31.1 x hp)
500 $6,200 + ($28.3 x hp)
Low-speed engines:
Operating hours Total annual cost
8,000 $78,500 + ($82.3 x hp)
6,000 $71,300 + ($74.8 X hp)
2,000 $56,800 + ($59.7 x hp)
500 $51,400 + ($54.1 x hp)
The total annual costs for an 80 hp, medium-speed engine range
from $8,480 for 500 hr/yr to $11,700 for 8,000 hr/yr. For a
4,000 hp, medium-speed engine, the total annual costs range from
$120,000 for 500 hr/yr to $177,000 for 8,000 hr/yr. The total
annual costs for an 80 hp low-speed engine range from $55,800
for 500 hr/yr to $85,300 for 8,000 hr/yr. For an 8,000 hp, low-
speed engine, the total annual costs range from $484,000 for
500 hr/yr to $737,000 for 8,000 hr/yr. The higher range of
annual costs for low-speed engines is attributable to the higher
capital costs for these engines relative to medium-speed engines.
6.2.6.3 Cost Effectiveness. The cost effectiveness
presented in this section is calculated using a controlled NOX
emission rate of 2 g/hp-hr (150 ppmv), consistent with most of
the emissions data presented in Chapter 5. The cost
effectiveness for medium-speed engines is presented in
Figure 6-10. For continuous-duty engines (8,000 hr/yr), the cost
effectiveness is approximately $l,200/ton for engines rated at
100 hp or less and decreases rapidly with increasing engine size
to less than $400/ton for a 1,000 hp engine. The cost-
effectiveness curve is relatively flat for engines rated above
6-38
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1,000 hp, decreasing slightly from $400/ton for a 1,200 hp engine
to $350/ton for an 8,000 hp engine.
For medium-speed engines operating less than 8,000 hr/yr,
cost effectiveness increases with decreasing operating hours.
The increase is relatively small for larger engines but increases
rapidly for smaller engines, especially engines less than
1,000 hp. The cost effectiveness for these smaller engines
ranges from approximately $4,000 to $14,000 per ton, increasing
as engine size and annual operating hours decrease.
As shown in Figure 6-11, for continuous-duty low-speed
engines, cost effectiveness for low-emission retrofit approaches
$8,800/ton for engines less than 100 hp but decreases rapidly for
larger engines. For engines above 1,000 hp, the cost-
effectiveness curve is relatively flat at less than $l,300/ton,
decreasing slightly with increasing engine size to a low of
approximately $750/ton for an 8,000 hp engine. A similar cost-
effectiveness trend applies to low-speed engines that operate
less than 8,000 hr/yr, but the cost effectiveness increases to a
high of over $90,000/ton for the smallest engines operating
500 hr/yr and decreases to approximately $15,000/ton or less for
engines above 1,000 hp operating 500 hr/yr. The cost-
effectiveness range from $24,000 to $92,000 per ton is not shown
on the plot in Figure 6-11 in order to more clearly present the
range of $0 to $10,000 per ton.
6.3 CONTROL COSTS FOR LEAN-BURN SI ENGINES
The applicable control techniques for lean-burn SI engines
are A/F adjustment, ignition timing retard, a combination of A/F
adjustment and ignition timing retard, SCR, and low-emission
combustion. The costs for these control techniques as applied to
lean-burn SI engines are presented in this section.
6.3.1 Control Costs for A/F Adjustment
6.3.1.1 Capital Costs. Adjusting the A/F to a leaner
setting requires a higher volume of air. For naturally aspirated
engines, this usually requires the addition of a turbocharger.
For turbocharged engines, either modifications to the existing
6-39
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turbocharger or replacement with a larger unit may be required.
Some manufacturers size the turbocharger to provide adequate
airflow at minimum engine speed and full torque, and at higher
engine speeds the output from the turbocharger is throttled or
regulated with a bypass arrangement to maintain the desired A/F.
For these engines, A/F adjustment to reduce NOX emission levels
may be possible by changing the control settings for the
turbocharger. Changing the turbocharger control setting,
however, reduces the operating speed range for the engine, as the
turbocharger capacity would not be adequate at lower engine
speeds. The lower speed range would limit the operating
flexibility for variable-speed applications (e.g., compressor and
pump) and increase BSFC and carbon monoxide (CO) emissions. The
airflow capacity in some engines can be increased by changing the
turbine nozzle ring in the existing turbocharger. Modifications
to the existing turbocharger would also require replacement of
the air manifold valves with an exhaust waste gate valve and
readjustment of the A/F control setpoint. According to
information provided by an engine manufacturer, the capital costs
for either scenario discussed above are expected to be similar to
or less than the costs shown in Section 6.2.1 for A/F adjustment
for rich-burn engines.1^
Naturally aspirated engines that cannot achieve a sufficient
increase in the A/F to reduce NOX emission levels would require
installation of a new turbocharger, and turbocharged engines
would require replacement of the existing turbocharger with a
larger unit. The capital costs presented in this section apply
to the addition/replacement of a turbocharger. Not all existing
engine designs will accommodate this retrofit.
The hardware costs associated with a new turbocharger were
estimated by an engine manufacturer to be $43,000 for engines up
1,100 hp, and $47,500 for engines between 1,100 and 2,650; the
associated labor cost were estimated to be 76 hr for either
engine size.1^ Assuming a linear relationship between hardware
costs and engine size yields the following equation:
6-40
-------
Hardware costs = $40,000 + ($3 x hp)
The PEC was calculated as the hardware cost plus labor costs
(76 hr x $27/hr). Direct and indirect installation factors of 25
and 20 percent of the PEC, respectively, were applied. The
contingency factor is 20 percent of the PEC, and sales taxes and
freight total 8 percent of the PEC.
Based on the above methodology, the total capital cost for
A/F adjustment for lean-burn engines that require a new
turbocharger are presented in Figure 6-12. The costs are linear
and can be estimated by the equation shown below:
Total capital costs = $73,000 + ($5.2 x hp)
The total capital costs range from $73,800 for a 200 hp engine to
$130,000 for an 11,000 hp engine.
6.3.1.2 Annual Costs. For engines that do not require a
new turbocharger, the annual costs are expected to be similar to
or less than those shown for A/F adjustment for rich-burn engines
in Section 6.2.1. For engines that require a new turbocharger,
the anticipated annual costs associated with A/F adjustment
include an increase in maintenance due to the addition of a new
or larger turbocharger, an increase in BSFC, an emission
compliance test, and capital recovery. The increased maintenance
cost is estimated as 10 percent of the PEC, plus an overhead cost
equal to 60 percent of the maintenance cost. Based on
information presented in Chapter 5, a fuel penalty of 3 percent
is assessed. Taxes, insurance, and administrative costs are
charged as shown in Table 6-2. The cost of a compliance test is
estimated at $2,440. The capital recovery is calculated as
discussed in Section 6.1.2.11.
Based on the above methodology, the total annual costs for
A/F adjustment for lean-burn engines retrofit with a new
turbocharger are presented in Figure 6-12. As Figure 6-12 shows,
6-41
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70
2000
4000 6000 8000
POWER OUTPUT. HP
10000
12000
10-
2000
40DO
6000
POWER OUTPUT, HP
6000
POWER OUTPUT. HP
12000
Figure 6-12. Total capital and annual costs and cost
effectiveness for A/F adjustment in lean-burn engines,
based on the addition of a new turbocharger to the
existing engine.
6-42
-------
the costs are essentially linear and can be approximated using
the following equations:
Operating hours Total annual cost
8,000 $21,100 + ($7.8 x hp)
6,000 $19,200 + ($6.0 x hp)
2,000 $15,300 + ($2.5 x hp)
500 $13,800 + ($1.2 x hp)
For a 200 hp engine, the total annual costs range from $14,000
for 500 hr/yr to $22,100 for 8,000 hr/yr. For an 11,000 hp
engine, the total annual costs range from $27,200 for 500 hr/yr
to $106,000 for 8,000 hr/yr.
6.3.1.3 Cost Effectiveness. As discussed in Chapter 5, the
expected range of NOX reduction for A/F adjustment for lean-burn
engines is 5 to 30 percent, and the cost effectiveness varies
according to the actual site-specific NOX reduction. The cost
effectiveness presented in this section is calculated using a NO...
Jv
reduction efficiency of 20 percent. For engines that do not
require turbocharger replacement, the cost effectiveness is
estimated to be similar to or less than those shown for A/F
adjustment for rich-burn engines in Section 6.2.1.
For those engines that require a new turbocharger, the cost
effectiveness is presented in Figure 6-12. For continuous-duty
(8,000 hr/yr) engines, the cost effectiveness ranges from a high
of approximately $3,700/ton for engines rated at 200 hp or less
and decreases rapidly as engine size increases, to $l,000/ton or
less for 1,000+ hp engines.
Cost effectiveness is higher for engines operating less than
8,000 hr/yr, especially for engines less than 1,000 hp. For
these smaller engines the cost effectiveness increases rapidly,
especially for engines that operate 2,000 hr/yr or less. The
cost effectiveness for these engines ranges from approximately
$2,400 to $7,500 per ton for 1,000 hp engines and from $10,500 to
$38,000 per ton for 200 hp engines. The cost-effectiveness range
from $12,000 to $38,000 per ton is not shown on the plot in
6-43
-------
Figure 6-12 in order to more clearly present the range of $0 to
$10,000 per ton.
6.3.2 Control Costs for Ignition Timing Retard
6.3.2.1 Capital Costs. For effective and sustained NOX
reduction with changes in engine load and ambient conditions, the
engine must be fitted with an electronic ignition control system
to automatically adjust the ignition timing. The total capital
costs for ignition timing retard applied to lean-burn SI engines
are expected to be the same as for rich-burn engines, presented
in Section 6.2.2.1 and shown in Figure 6-13.
6.3.2.2 Annual Costs. The anticipated annual costs
associated with ignition timing retard include an increase in
maintenance due to the addition of the electronic ignition
control system, an increase in BSFC, an emission compliance test,
and capital recovery. The increased maintenance cost is
estimated as 10 percent of the PEC, plus an overhead cost equal
to 60 percent of the maintenance cost. Based on information
presented in Chapter 5, a fuel penalty of 3 percent is assessed.
Taxes, insurance, and administrative costs are charged as shown
in Table 6-2, and a cost of $2,440 is included for emissions
testing. The capital recovery is calculated as discussed in
Section 6.1.2.11.
Based on the above methodology, the total annual costs for
ignition timing retard for lean-burn engines are presented in
Figure 6-13. As Figure 6-13 shows, the costs are essentially
linear and can be approximated using the following equations:
Operating hours Total annual cost
8,000 $6,840 + ($6.8 x hp)
6,000 $6,250 + ($5.2 x hp)
2,000 $5,070 + ($1.8 x hp)
500 $4,620 + ($0.6 x hp)
For a 200 hp engine, the total annual costs range from $4,460 for
500 hr/yr to $7,210 for 8,000 hr/yr. For an 11,000 hp engine,
6-44
-------
S 3O
g
8 IS orv
«z £
£ Iff
b '«
-J
POWER OUTPUT, HP
12000
2000
4000 6000 8000
POWER OUTPUT, HP
10000
12000
Figure 6-13. Total capital and annual costs and cost
effectiveness for ignition timing retard in lean-burn SI
engines, based on installation of an electronic
ignition system.
6-45
-------
the total annual costs range from $10,800 for 500 hr/yr to
$81,100 for 8,000 hr/yr.
6.3.2.3 Cost Effectiveness. As discussed in Chapter 5, the
expected range of NOX reduction for the ignition retard for
lean-burn engines is 0 to 20 percent, and the cost effectiveness
varies according to the actual site-specific NO,, reduction. The
J^
cost effectiveness presented in this section is calculated using
a NOX reduction efficiency of 10 percent. For engine
installations already equipped with an electronic ignition
control system, no additional equipment purchase is necessary,
and the cost effectiveness is estimated to be less than
$l,000/ton for all but the smallest engines operating in stand-by
applications.
For those engines which require installation of an
electronic ignition system, the cost effectiveness is presented
in Figure 6-13. For continuous-duty engines (8,000 hr/yr), the
cost effectiveness ranges from a high of approximately $2,400/ton
for engines rated at 200 hp or less down to less than $l,800/ton
for engines rated at 1,000+ hp.
Cost effectiveness is higher for engines operating at less
than 8,000 hr/yr, especially for engines less than 1,000 hp. For
these smaller engines the cost effectiveness increases rapidly,
especially for engines less than 1,000 hp that operate
2,000 hr/yr or less. The cost effectiveness for these engines
ranges from approximately $1,800 to $5,000 per ton for 1,000 hp
engines to $6,800 to over $24,000 per ton for 200 hp engines.
The cost-effectiveness range from $10,000 to $24,000 per ton is
not shown on the plot in Figure 6-13 in order to more clearly
present the range of $0 to $10,000 per ton.
6.3.3 Control Costs for A/F Adjustment and Ignition Timing
Retard
6.3.3.1 Capital Costs. The capital costs presented in this
section apply to installing both a new turbocharger and an
electronic ignition system on the engine. Where an existing
engine does not require modification (i.e., the turbocharger
capacity is adequate for A/F adjustment and the engine is
6-46
-------
equipped with an electronic ignition system), no additional
equipment is required. In this case, capital costs are expected
to be approximately $4,000 or less. This cost includes an
emission compliance test and approximately 25 labor hours and
associated direct/indirect and contingency factors to perform the
adjustments on the engine. Where an existing engine requires
only one of the control system modifications (i.e., turbocharger
modification/replacement or electronic ignition system), the
capital costs are presented in Sections 6.3.1 and 6.3.2.
For engines that require installation of a new turbocharger
and an electronic ignition system, the capital costs are
estimated to be equal to the sum of the costs for each system.
The combined PEC for these systems can be approximated by the
following equations:
Engines to 1,000 hp: PEC » $49,600 + ($3 x hp)
Engines to 1,001 to 2,500 hp: PEC = $52,100 + ($3 x hp)
Engines over 2,500 hp: PEC = $57,100 + ($3 x hp)
Direct and indirect installation factors are each estimated at
20 percent of the combined PEC. The contingency factor is
20 percent of the PEC, and sales taxes and freight are 8 percent
of the PEC.
Based on the above methodology, the total capital costs for
the combination of A/F adjustment and ignition timing retard for
lean-burn engines requiring both a new turbocharger and
electronic ignition system are presented in Figure 6-14. The
costs can be approximated by the following equations:
Engines to 1,000 hp: TCC = $83,200 + ($5.0 x hp)
Engines to 2,500 hp: TCC = $87,500 + ($5.0 x hp)
Engines above 2,500 hp: TCC = $95,800 + ($5.0 x hp)
The total capital costs range from $85,700 for a 200 hp engine to
$151,000 for an 11,000 hp engine.
6-47
-------
BO
6000
POWER OUTPUT. HP
12000
$ 000 HOURS
6.000 HOURS
2.000 HOURS
500 HOURS
4000 6000 8000
POWER OUTPUT, HP
POWER OUTPUT. HP
Figure 6-14. Total capital and annual costs and cost
effectiveness for A/F adjustment and ignition timing retard in
lean-burn SI engines, based on addition of a new turbocharger
and an electronic ignition system.
6-48
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6.3.3.2 Annual Costs. The anticipated annual costs
associated with the combination of A/F adjustment and ignition
timing retard include an increase in maintenance due to the
installation of a new turbocharger and electronic ignition
control systems, an increase in BSFC, an emission compliance
test, and capital recovery. The increased maintenance cost is
estimated as 10 percent of the PEC, plus an overhead cost equal
to 60 percent of the maintenance cost. Based on information
presented in Chapter 5, a fuel penalty of 5 percent is assessed.
Taxes, insurance, and administrative costs are charged as shown
in Table 6-2, and the compliance test cost is estimated at
$2,440. The capital recovery is calculated as discussed in
Section 6.1.2.11.
Based on the above methodology, the total annual costs for
the combination of A/F adjustment and ignition timing retard for
lean-burn engines are presented in Figure 6-14. As Figure 6-14
shows, the costs are essentially linear and can be approximated
using the following equations:
Operating hours Total annual cost
8,000 $24,900 + ($12.4 x hp)
6,000 $22,500 + ($9.5 x hp)
2,000 $17,600 + ($3.8 x hp)
500 $15,700 + ($1.7 x hp)
For a 200 hp engine, the total annual costs range from $15,700
for 500 hr/yr to $26,000 for 8,000 hr/yr. For an 11,000 hp
engine, the total annual costs range from $33,600 for 500 hr/yr
to $160,000 for 8,000 hr/yr.
6.3.3.3 Cost Effectiveness. As discussed in Chapter 5, the
expected range of NOY reduction for the combination of A/F
J^
adjustment and ignition retard for lean-burn engines is 20 to
40 percent, and the cost effectiveness varies according to the
actual site-specific NOX reduction. The cost effectiveness
presented in this section is calculated using a NC- reduction
Jt
efficiency of 25 percent. For engine installations already
6-49
-------
equipped with both automatic A/F and electronic ignition control
systems, no additional equipment purchase is necessary, and the
cost effectiveness is estimated to be less than $l,000/ton for
all but the smallest engines operating in stand-by applications.
For those engines equipped with provisions for one but not both
control systems, the second control system must be purchased and
installed. The cost effectiveness in this case is less than that
shown in Figure 6-12 or 6-13 for either control used
independently, because the 25 percent NOX reduction efficiency is
higher than that used in either of these figures.
For continuous-duty engines, the cost effectiveness for A/F
adjustment plus ignition timing retard in lean-burn engines is
over $3,500/ton for a 200 hp engine but decreases rapidly as
engine size increases. For engines above 1,000 hp, the cost-
effectiveness curve is relatively flat at approximately
$l,000/ton for a 1,000 hp engine and decreases to approximately
$400/ton for an 11,000 hp engine.
A similar cost-effectiveness trend applies for engines that
operate less than 8,000 hr/yr, but the cost effectiveness
increases to a high of $34,000/ton for the smallest engines
operating 500 hr/yr and decreases to less than $9,000/ton for
1,000 hp engines and less than $2,000/ton above 5,000 hp. The
cost-effectiveness range from $10,000 to $34,000 per ton is not
shown on the plot in Figure 6-14 in order to more clearly present
the range of $0 to $10,000 per ton.
6.3.4 Control Costs for SCR Applied to Lean-Burn SI Engines
6.3.4.1 Capital Costs. Capital costs for SCR are estimated
using installed cost estimates available from three
sources.5'22'23 These cost estimates are presented in
Figure 6-15 and include the catalyst, reactor housing and
ductwork, ammonia injection system, controls, and engineering and
installation of the equipment. The line drawn on Figure 6-15 was
used to develop the capital costs for SCR systems, and the
equation of this line is given below:
6-50
-------
(spuBsnoiii)
$ 1SOO IVlldVO
JJ
CQ
rt
u
T)
0)
4J
•H
JJ
»
3 1
u
rt
4J
rt
o
0)
-H
4J
U
(1)
rH
0)
CQ
0)
CQ
4J
CQ
O
U
(U
0)
CQ
It
cn
i-i
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CQ
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tn
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6-51
-------
Installed vendor cost estimates = $93,800 + ($42 x hp)
It is expected that most SCR installations would require a
GEMS, and the additional cost for this is estimated at $85,000,
regardless of engine size.5 The total PEC for SCR with a CEMS
can be approximated using the following equation:
Purchased equipment cost - $179,000 + ($42 x hp)
This equation includes installation costs, so the direct and
indirect installation factors are reduced to 25 and 20 percent of
the PEC, respectively. The contingency factor is 20 percent of
the PEC. Sales taxes and freight are assessed as shown in
Table 6-1.
Based on the above methodology, the total capital costs for
SCR for lean-burn SI engines are presented in Figure 6-16. These
costs are essentially linear and can be estimated by the
following equation:
Total capital costs = $310,000 + ($72.7 x hp)
The total capital costs range from $324,000 for a 200 hp engine
to $1,110,000 for an 11,000 hp engine.
6.3.4.2 Annual Costs. The anticipated annual costs
associated with SCR include an increase in operating labor and
maintenance due to the addition of the ammonia injection and
CEMS; an increase in BSFC; catalyst cleaning, replacement, and
disposal; an emission compliance test; and capital recovery. The
increased operating labor is calculated as 3 hr per 8-hr shift,
with supervisory labor as an additional 15 percent of operating
labor. Maintenance costs are estimated as 10 percent of the PEC,
plus an overhead cost equal to 60 percent of the maintenance
cost. Based on information presented in Chapter 5, a fuel
penalty of 0.5 percent is assessed.
Based on information provided in References 8 and 20, the
volume of catalyst for SCR applications is approximately twice
6-52
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6000
POWER OUTPUT HP
12000
800
2000
40DO
6000
POWER OUTPUT, HP
80OO
10000
12000
6000
POWER OUTPUT HP
12000
Figure 6-16. Total capital and annual costs and cost
effectiveness for selective catalytic reduction for lean-burn SI
engines, including a continuous emission monitoring system.
6-53
-------
that required for NSCR applications. This is due in part to the
higher airflows associated with the scavenge requirements for
2-cycle engines; other factors were not discussed in the
references. The cleaning cost used for NSCR in Section 6.2.5 was
therefore doubled to $1.50/hp for SCR catalyst cleaning, plus
10 percent for freight. A cleaning schedule of once every 1.5 yr
(12,000 hr) is used for SCR, consistent with that for NSCR. A
catalyst life of 3 yr (24,000 hr), consistent with guarantees
offered by most catalyst vendors, is used. This results in one
catalyst cleaning operation prior to catalyst replacement, or the
requirement of one cleaning operation every 3 yr (36,000 hr)*
The annual cost for cleaning based on this schedule is calculated
as $0.50/hp plus 10 percent for freight.
A catalyst replacement cost of $10/hp is estimated based on
cost information from Reference 5. Using a catalyst replacement
schedule of every 3 yr, the annual cost is calculated as
$3.33/hp, plus 10 percent for freight.
To date, very little cost information is available for
disposal of spent catalyst material because most catalyst
applications have not yet replaced existing catalyst material.
Most catalyst vendors accept return of spent catalysts, but
details of these return policies and associated costs, if any,
were not provided. Catalyst disposal costs were estimated at
$15 per cubic foot ($15/ft3) by one catalyst vendor for spent
zeolite catalyst material. Based on a cost of $l5/ft3 and an
estimated catalyst volume of 0.002 ft3/hp, the catalyst disposal
cost is $0.03/hp.8'20 The annual cost for disposal, using a 3-yr
catalyst life, is $0.01/hp. This cost applies to nonhazardous
material disposal, and disposal costs are expected to be higher
for spent catalyst material that contains vanadium pentoxide,
where this material has been classified as a hazardous waste by
State or local agencies.
The operating cost for the ammonia system includes the cost
for the ammonia (NH3) and the energy required for ammonia
vaporization and injection. Costs for anhydrous ammonia were
used because it is the most common ammonia system. Steam is
6-54
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selected for ammonia vaporization and dilution to a 5 percent
ammonia solution by volume for injection. The cost of anhydrous
ammonia was estimated at $250/ton.24 Steam costs were estimated
at $6/1,000 lb.2 Using a NOX/NH3 molar ratio of 1.0, the annual
costs for ammonia and steam consumption are:
Ammonia = N x hp x hours x (NH3 MW/NOX MW)
(1 ton/2000 lb) x $250/ton
= N x hp x hours x 1.01 x 10"4 and
x (1 lb/454 g) x
Steam = N x hp x hours x (NH3 MW/NOX MW) x (1 lb/454 g) x
(H20 MW/NH3 MW) x (95/5) x $6/1,000 lb
= N x hp x hours x 9.83 x 10"5
where:
N
hp
hours
NH-
NO,
MW
MW
H20 MW
uncontrolled NOX emissions, g/hp-hr;
engine horsepower;
annual operating hours;
molecular weight of NH3 = 17.0;
molecular weight of NOX = 46.0; and
molecular weight of H20 = 18.0.
Taxes, insurance, and administrative costs are charged as shown
in Table 6-2, and an emission test cost of $2,440 is included.
The capital recovery is calculated as discussed in
Section 6.1.2.11.
Based on the above methodology, the total annual costs for
SCR are presented in Figure 6-16. As this figure shows, the
costs are essentially linear and can be approximated using the
following equations:
6-55
-------
Operating hours Total annual cost
8,000 $171,000 + ($49.7 x hp)
6,000 $140,000 + ($40.0 x hp)
2,000 $79,300 + ($20.6 x hp)
500 $56,400 + ($13.3 x hp)
For a 200 hp engine, the total annual costs range from $59,100
for 500 hr/yr to $181,000 for 8,000 hr/yr. For an 11,000 hp
engine, the total annual costs range from $203,000 for 500 hr/yr
to $717,000 for 8,000 hr/yr.
6.3.4.3 Cost Effectiveness. As discussed in Chapter 5, the
achievable NOX reduction efficiency for SCR is 90 percent, and
this figure is used to calculate the effectiveness presented in
Figure 6-16. For continuous-duty (8,000 hr/yr) engines, the cost
effectiveness ranges from a high of approximately $6,800/ton for
engines rated at 200 hp or less and decreases rapidly as engine
size increases, to approximately $l,600/ton at 1,000 hp and
$500/ton at 11,000 hp.
Cost effectiveness is higher for engines operating less than
8,000 hr/yr, especially for engines under 1,000 hp. For these
smaller engines, the cost effectiveness increases rapidly as
engine size decreases, especially for engines operating
2,000 hr/yr or less. The cost effectiveness for these engines
ranges from approximately $3,000 to $8,500 per ton for 1,000 hp
engines and increases to $12,000 to over $35,000 per ton for
200 hp engines. The portion of the cost-effectiveness range from
$13,000 to $35,000 per ton is not shown on the plot in Figure 6-
16 in order to more clearly present the range of $0 to $10,000
per ton.
6.3.5 Control Costs for Conversion to Low-Emission Combustion
Because the hardware and installation requirements for
conversion to low-emission combustion are essentially the same
for either rich-burn or lean-burn engines, the capital costs are
considered to be same for either engine type. Annual costs are
also essentially the same, except that a fuel credit of 3 percent
is expected for lean-burn engine conversions, compared to
6-56
-------
1 percent for rich-burn engines. This difference in fuel costs
is a very minor portion of the total annual costs, and the costs
and cost effectiveness presented in Section 6.2.6 are considered
to apply for low-emission conversion of either rich-burn or lean-
burn engines.
6.4 CONTROL COSTS FOR COMPRESSION IGNITION (CI) ENGINES
The control techniques for diesel and dual-fuel engines are
injection timing retard and SCR. For dual-fuel engines, low-
emission combustion engine designs are also available from some
manufacturers. The cost methodologies for control techniques
applied to CI engines are presented in this section.
6.4.1 Control Costs For Injection Timing Retard
6.4.1.1 Capital Costs. It is expected that injection
timing retard for a CI engine requires an automated electronic
control system similar to ignition timing adjustment for an SI
engine. Capital costs, therefore, are estimated on the same
basis as ignition retard costs for SI engines, presented in
Section 6.2.2.1. The total capital costs for injection timing
retard are shown in Figures 6-17 and 6-18 for diesel and dual-
fuel engines, respectively.
6.4.1.2 Annual Costs. Annual costs for injection timing
retard are calculated using the same methodology as that used for
ignition timing retard for SI engines in Section 6.2.2.2. A
3 percent fuel penalty is used for both diesel and dual-fuel
engines. The total annual costs for injection timing retard in
CI engines are presented in Figures 6-17 and 6-18 for diesel and
dual-fuel engines, respectively. The costs are essentially
linear and can be estimated by the following equations:
Diesel engines:
Operating hours Total annual costs
8,000 $6,150 + ($9.2 x hp)
6,000 $5,680 + ($6.9 x hp)
2,000 $4,740 + ($2.5 x hp)
500 $4,390 + ($0.8 x hp)
6-57
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24-
20-
18-
16-
1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
3000 4000 MOO
POWER OUTPUT HP
8000
Figure 6-17. Total capital and annual costs and cost
effectiveness for injection timing retard in diesel engines,
based on installation of an electronic ignition system.
6-58
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a: 24-
« ¥20.
05
o 8
<1 18
! 1(JOO 2dOO
3dOO 4000 5(500 6000 7(300 80
POWER OUTPUT, HP
3000 4CJOO SCfeO
POWER OUTPUT. HP
8.000 HOURS
6.000 HOURS
2.000 HOURS
500 HOURS
3000 4000 5000
POWER OUTPUT, HP
Figure 6-18. Total capital and annual costs and cost
effectiveness for injection timing retard in dual-fuel engines,
based on installation of an electronic ignition system.
6-59
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Dual-fuel engines:
Operating hours Total annual costs
8,000 $7,060 + ($6.4 x hp)
6,000 $6,380 + ($4.9 x hp)
2,000 $5,040 + ($1.8 x hp)
500 $4,530 + ($0.7 x hp)
The total annual costs for an 80 hp diesel engine range from
$4,390 for 500 hr/yr to $6,230 for 8,000 hr/yr. For an 8,000 hp
diesel engine, the total annual costs range from $10,600 for
500 hr/yr to $77,900 for 8,000 hr/yr. The total annual costs for
a 700 hp dual-fuel engine range from $4,650 for 500 hr/yr to
$10,300 for 8,000 hr/yr. For an 8,000 hp dual-fuel engine, the
total annual costs range from $9,300 for 500 hr/yr to $57,200 for
8,000 hr/yr.
6.4.1.3 Cost Effectiveness. Based on information in
Chapter 5, cost effectiveness is calculated for diesel and dual-
fuel engines using a NOX reduction efficiency of 25 and
20 percent, respectively. For diesel engines the cost
effectiveness is presented in Figure 6-17 and for continuous-duty
diesel engines ranges from a high of approximately $3,000/ton for
an 80 hp engine to $375/ton for an 8,000 hp engine. The cost
effectiveness drops rapidly and is less than $l,000/ton for
continuous-duty diesel engines larger than 300 hp. Cost-
effectiveness figures increase as annual operating hours
decrease, and for diesel engines operating 500 hr/yr range from
over $33,000/ton for an 80 hp engine to as low as $802/ton for an
8,000 hp engine. The cost-effectiveness range from $10,000 to
$33,000 per ton is not shown on the plot in Figure 6-17 in order
to more clearly present the range of $0 to $10,000 per ton.
For dual-fuel engines, the cost effectiveness is presented
in Figure 6-18. For continuous-duty dual-fuel engines, cost
effectiveness is $l,000/ton or less for all engines in this
study, ranging from a high of approximately $l,000/ton for a
700 hp engine to $500/ton for an 8,000 hp engine. Cost-
effectiveness figures increase as annual, operating hours
6-60
-------
decrease, and for diesel engines operating 500 hr/yr range from
over $7,100/ton for an 80 hp engine to a low of $l,250/ton for an
8,000 hp engine.
6.4.1.4 Control Costs for Diesel and Dual-Fuel SCR
Applications.
6.4.1.5 Capital Costs. Capital cost estimates for diesel
and dual-fuel engine SCR applications were provided by two SCR
vendors.23,25 These cost estimates are presented in Figure 6-19.
One vendor provided an equation to estimate costs for base-metal
catalyst systems; the other vendor's cost estimates are for
zeolite catalyst systems and were given as a range, in $/hp.
Both vendors said that the costs are for systems that achieve a
NOV reduction efficiency of 90 percent. The capital costs shown
J*L
in Figure 6-19 include the catalyst, reactor housing and
ductwork, ammonia injection system, controls, and engineering and
installation of this equipment. The line in this figure is used
to represent the installed cost for SCR for either a base-metal
or zeolite catalyst, and the equation of this line is given
below:
Capital costs = $22,800 + ($56.4 x hp)
This equation is similar to that for SI engine SCR applications;
the lower capital costs for CI engines are expected to be the
result of lower exhaust flows and NOX emission rates for CI
engines. It is expected that most SCR installations would
require a CEMS, and the additional cost for this is estimated at
$85,000, regardless of engine size.25 The total PEC for SCR with
a CEMS can be estimated using the following equation:
Purchased equipment cost = $108,000 + ($56.4 x hp)
This equation includes installation costs, so the direct and
indirect installation factors are reduced to 25 and 20 percent of
the PEC, respectively. The contingency factor is 20 percent of
6-61
-------
CO
$ 1SOO IVlldVO
•O
4J
4J
DQ
(1)
-------
the PEC. Sales taxes and freight are assessed as shown in
Table 6-1.
Based on the above methodology, the total capital costs for
SCR for diesel and dual-fuel engines are presented in
Figures 6-20 and 6-21, respectively, and can be estimated by the
following equation:
Total capital costs = $187,000 + ($98 x hp)
The total capital costs for diesel engines range from $195,000
for an 80 hp engine to $967,000 for a 8,000 hp engine. The total
capital costs for dual-fuel engines range from $255,000 for a
700 hp engine to $967,000 for a 8,000 hp engine.
6.4.1.6 Annual Costs. The anticipated annual costs
associated with SCR include an increase in operating labor and
maintenance due to the addition of the ammonia injection and
CEMS; an increase in BSFC; catalyst cleaning, replacement, and
disposal; an emission compliance test; and capital recovery. The
cost methodology used to estimate the costs for
operating/supervisory labor, maintenance, ammonia, steam diluent,
and fuel penalty are the same as those for SI engines presented
in Section 6.3.4.2.
The costs associated with catalyst cleaning, replacement,
and disposal are estimated using the same methodology as that
presented in Section 6.3.4.2, but the annual costs are reduced to
75 percent of those used for SI engines. The 75 percent figure
is approximately the ratio of the capital cost estimate factors
of $42/hp to $56/hp used in the purchased equipment equations,
and this 75 percent figure is expected to compensate for the
reduced catalyst volume required for CI engines. Some base-metal
catalyst vendors said that cleaning requirements are more
frequent for diesel-fueled applications, and so the cleaning
schedule is adjusted from every 12,000 hr used for SI engines to
every 8,000 hr. The annual costs for catalyst cleaning,
replacement, and disposal for continuous-duty applications were
estimated at $0.76/hp, $2.50/hp, and $0.01/hp, respectively, plus
6-63
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1000
3000 400) 5000
POWER OUTPUT, HP
8000
1000
2000
3000 4000 5000
POWER OUTPUT, HP
6000
8000
3000 4000 5000
POWER OUTPUT. HP
no
Figure 6-20. Total capital and annual costs and cost
effectiveness for selective catalytic reduction for diesel
engines, including a continuous emission monitoring system.
6-64
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1000
2000
3000 4000 5000
POWER OUTPUT, HP
6000
7000
8000
1000
2(500
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
3000 4000 5000
POWER OUTPUT.*
8000
Figure 6-21. Total capital and annual costs and cost
effectiveness for selective catalytic reduction for dual-fuel
engines, including a continuous emission monitoring system.
6-65
-------
10 percent for freight. The disposal cost applies to
nonhazardous material disposal, and disposal costs are expected
to be higher for spent catalyst material that contains vanadium
pentoxide where this material has been classified as a hazardous
waste by State or local agencies.
Plant overhead, taxes, insurance, and administrative costs
are calculated as described in Section 6.1.3. A cost of $2,440
is included for emission testing, and capital recovery is
calculated as discussed in Section 6.1.2.11.
Using this methodology, the total annual costs for diesel
engine SCR applications are presented in Figure 6-20 and can be
estimated using the following equations:
Operating hours Total annual cost
8,000 $141,000 + ($47.8 x hp)
6,000 $113,000 + ($39.5 x hp)
2,000 $58,100 + ($22.9 x hp)
500 $37,300 + ($16.7 x hp)
For dual-fuel engines, the total annual costs for SCR
applications are presented in Figure 6-21 and can be estimated
using the following equations:
Operating hours Total annual cost
8,000 $141,000 + ($42.1 x hp)
6,000 $113,000 + ($35.2 x hp)
2,000 $58,100 + ($21.5 x hp)
500 $37,300 + ($16.3 x hp)
The total annual costs for an 80 hp diesel engine range from
$38,700 for 500 hr/yr to $145,000 for 8,000 hr/yr. For an
8,000 hp diesel engine the total annual costs range from $171,000
for 500 hr/yr to $523,000 for 8,000 hr/yr. The total annual
costs for a 700 hp dual-fuel engine range from $48,800 for
500 hr/yr to $170,000 for 8,000 hr/yr. For an 8,000 hp dual-fuel
6-66
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engine, the total annual costs range from $168,000 for 500 hr/yr
to $478,000 for 8,000 hr/yr.
6.4.1.7 Cost Effectiveness. Zeolite catalyst vendors
guarantee a 90 percent NOX reduction efficiency for diesel and
dual-fuel SCR applications. Base-metal catalyst vendors also
offer a 90 percent NOX reduction efficiency, although some
vendors said that cleaning requirements increase for this
reduction efficiency over that required for an 80 percent
reduction level. A 90 percent NOX reduction efficiency is used
to calculate cost effectiveness in this section.
The cost effectiveness for diesel engines is presented in
Figure 6-20 and for continuous-duty diesel engines ranges from a
high of over $19,000/ton for an 80 hp engine to less than
$700/ton for an 8,000 hp engine. The cost effectiveness drops
rapidly and is less than $3,000/ton for continuous-duty diesel
engines larger than 600 hp. Cost-effectiveness figures increase
as annual operating hours decrease, and for diesel engines
operating 500 hr/yr range from over $80,000/ton for an 80 hp
engine a low of $3,900/ton for an 8,000 hp engine. The cost-
effectiveness range from $32,000 to $82,000 per ton is not shown
on the plot in Figure 6-20 in order to more clearly present the
range of $0 to $10,000 per ton.
For dual-fuel engines, the cost effectiveness is presented
in Figure 6-21. For continuous-duty dual-fuel engines, cost
effectiveness ranges from a high of approximately $3,600/ton for
a 700 hp engine to approximately $900/ton for an 8,000 hp engine.
Cost-effectiveness figures increase as annual operating hours
decrease, and for dual-fuel engines operating 500 hr/yr range
from over $16,000/ton for an 80 hp engine to a low of $5,000/ton
for an 8,000 hp engine. The cost-effectiveness range from
$10,000 to $16,000 per ton is not shown on the plot in Figure 6-
21 in order to more clearly present the range of $0 to $10,000
per ton.
6-67
-------
6.4.2 Control Coats for Conversion to Low-Emission Combustion
Dual-fuel engine manufacturers have developed low-emission
engine designs for some dual-fuel engines. These engine designs
are relatively new, and limited cost information was available to
develop the costs presented in this section.
The hardware and labor requirements to retrofit low-emission
combustion to an existing engine are similar in scope to a major
engine overhaul. If the low-emission combustion retrofit is
scheduled to coincide with a scheduled major engine overhaul, the
capital costs and cost-effectiveness figures will be less than
those shown in this section.
6.4.2.1 Capital Costs. Capital costs for the hardware to
retrofit existing dual-fuel engines to low-emission combustion
were available from only one engine manufacturer for one line of
engines.1^ No incremental costs for low-emission designs
compared to conventional engine costs were available for new
installations. The retrofit hardware costs were approximately
30 percent higher than for retrofit of a comparable low-speed,
large-bore SI engine. Applying this 30 percent factor to the
costs shown in Section 6.2.6.1 results in the following equation:
Retrofit hardware costs = $182,000 + ($200 x hp)
The low-emission design requires higher combustion airflows and
an upgraded turbocharger, similar to SI designs. Consistent with
the SI engine cost methodology, the retrofit hardware cost is
multiplied by 1.3 to cover the cost of replacing the inlet and
exhaust systems and aerial cooler. Taxes and freight are
assessed as shown in Table 6-1. Direct and indirect installation
factors of 25 and 20 percent, respectively, are included, along
with a contingency factor of 20 percent. Based on this
methodology, the total capital costs for retrofit of existing
dual-fuel engines to low-emission combustion are presented in
Figure 6-22 and can be estimated by the following equation:
6-68
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1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
1 V
V
09-
0.8-
I
8
o
0.6-
~ 0.5-
0.4-
03- >
0.2-
0.1-
1000
MOO 30DO 4000 5000
POWER OUTPUT, HP
60DO
7000
8.000 HOURS
6,000 HOURS
2.000 HOURS
500 HOURS
8000
1000
2000
3000 4000 5000
POWER OUTPUT. HP
6000
7000
8000
Figure 6-22. Total capital and annual costs and cost
effectiveness for retrofit to low-emission combustion
for dual-fuel engines.
6-69
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Total capital cost - $405,000 + ($450 x hp)
The total capital costs range from $720,000 for a 700 hp engine
to $4,000,000 for an 8,000 hp engine.
6.4.2.2 Annual Costs. Annual costs associated with
low-emission combustion include maintenance and overhead, fuel
consumption, taxes, insurance, administrative costs, and capital
recovery. No power reduction results from low-emission
combustion, and no increase in operating labor is expected.
Maintenance costs are calculated as 10 percent of the PEC,
plus overhead equal to 60 percent of maintenance costs. A fuel
penalty of 3 percent is assessed and is calculated based on
100 percent natural gas fuel to simplify the calculation.
(Diesel fuel represents only l percent of the total fuel
consumption.) Plant overhead, taxes, insurance, administrative
costs, and capital recovery are calculated as discussed in
Section 6.1. An emission test cost of $2,440 is also included.
The capital recovery cost is included as discussed in
Section 6.1.2.11.
The resultant total annual costs for low-emission combustion
for dual-fuel engines are presented in Figure 6-22, and can be
estimated by the following equations:
Operating hours Total annual cost
8,000 $102,000 + ($115 x hp)
6,000 $92,200 + ($103 x hp)
2,000 $72,800 + ($79.3 x hp)
500 $65,500 + ($70.4 x hp)
The total annual costs for a 700 hp dual-fuel engine range from
$115,000 for 500 hr/yr to $182,000 for 8,000 hr/yr. For an 8,000
hp dual-fuel engine, the total annual costs range from $628,000
for 500 hr/yr to $1,020,000 for 8,000 hr/yr.
6.4.2.3 Cost Effectiveness. Data presented in Chapter 5
suggests that controlled NOX emission levels for low-emission
dual-fuel engine designs range from 1.0 to 2.0 g/hp-hr. A
6-70
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2.0 g/hp-hr controlled NOX emission level is used to calculate
cost effectiveness, as presented in Figure 6-22.
For continuous-duty engines (8,000 hr/yr), the cost
effectiveness is approximately $4,560/ton for a 700 hp engine and
decreases to $2,250/ton for an 8,000 hp engine. The cost
effectiveness increases for engines operating less than
8,000 hr/yr, and is $46,100/ton for a 700 hp engine operating
500 hr/yr and $22,100/ton for an 8,000 hp engine operating
500 hr/yr. The cost-effectiveness range from $30,000 to
$46,000 per ton is not shown on the plot in Figure 6-22 in order
to more clearly present the range of $0 to $10,000 per ton.
6.5 REFERENCES FOR CHAPTER 6
l. Letter and attachment from Welch, R. W., Interstate Natural
Gas Association of America, to Neuffer, W. J., EPA/ISB.
December 23, 1993. Review of draft reciprocating engine ACT
document.
2. OAQPS Control Cost Manual (Fourth Edition). EPA 450/3-90-
006. January 1990. Chapter 2.
3. Monthly Energy Review. Energy Information Administration.
March 1991. p. 113.
4. Radian Corporation. Background Information Document, Review
of 1979 Gas Turbine New Source Performance Standards.
U. S. Environmental Protection Agency. Research Triangle
Park, NC. Contract No. 68-02-3816. 1985.
5. Benson, C. E., K. R. Benedek, and P. J. Loftus (Arthur D.
Little, Inc.). Improved Selective Catalytic NOX Control
Technology for Compressor Station Reciprocating Engines.
Prepared for the Gas Research Institute. Chicago.
GRI-92/0364. September 1992.
6. Evaluation of NOX Control Technologies for Gas-Fired
Internal "Reciprocating" Combustion Engines. Arthur D.
Little, Inc., Santa Barbara, CA. March 6, 1989.
7. Letter and attachments from Wax, M. J., Institute of Clean
Air Companies (formerly Industrial Gas Cleaning Institute),
to Neuffer, W. J., EPA/ISB. September 17, 1992. Review of
draft reciprocating engine ACT document.
8. Letter and attachments from Henegan, D., Norton Company, to
Snyder, R. B., Midwest Research Institute. March 28, 1991.
Catalytic controls for internal combustion engines.
6-71
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9. Letter and attachments from Stachowicz, R. w., Waukesha
Engine Division of Dresser Industries, Inc., to Snyder,
R. B., Midwest Research Institute. September 16, 1991.
Internal combustion engines.
10. Letter and attachments from Miklos, R. A., Cooper-Bessemer
Reciprocating Products Division, to Jordan, B. C., EPA.
January 21, 1992. Internal combustion engines.
11. Letter and attachments from Dowdall, D. C., Caterpillar
Inc., to Jordan, B. C., EPA. March 25, 1992. Internal
combustion engines.
12. Letter and attachments from locco, D. E., Dresser-Rand, to
Snyder, R. B., Midwest Research Institute. October 1, 1991.
Internal combustion engines.
13. Letter and attachments from McCormick, W. M., Cooper
Industries - Ajax Superior Division, to Snyder, R. B.,
Midwest Research Institute. September 16, 1991. Internal
combustion engines.
14. Letter and attachments from Fisher, J., Detroit Diesel
Corporation, to Neuffer, W., EPA. June 10, 1992. Internal
combustion engines.
15. Letter and attachments from Axness, J., Deere Power Systems
Group, to Snyder, R., Midwest Research Institute. August
30, 1991. Internal combustion engines.
16. Letter and attachment from Shade, W. N., Ajax-Superior
Division of Cooper Industries, to Snyder, R. B., Midwest
Research Institute. March 19, 1993. Control techniques and
costs for reciprocating engines.
17. Letter and attachment from Dowdall, D. C., Caterpillar
Incorporated, to Snyder, R. B., Midwest Research Institute.
April 16, 1993. Effect of parametric adjustments on
reciprocating engines.
18. Minutes from meeting dated March 4, 1993 with
representatives from the Interstate Natural Gas Association
of America, U. S. Environmental Protection Agency, and
Midwest Research Institute. March 9, 1993. Review of draft
reciprocating engine ACT document.
19. Letter and attachments from Mikkelsen, B. L., Emissions
Plus, Inc., to Snyder, R. B., Midwest Research Institute.
April 8, 1992. Prestratified charge systems for 1C engines.
20. Letter from Weeks, M. D., Emission Control Systems, Inc., to
Neuffer, W. J., EPA/ISB. November 2, 1992. Review of draft
reciprocating engine ACT document.
6-72
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21. Letter and attachments from Stachowicz, R. W., Waukesha
Engine Division of Dresser Industries, Inc., to Cassidy,
M. A., Midwest Research Institute. June 14, 1991. Internal
combustion engine emissions control.
22. Letter from Wax, M. J., Institute of Clean Air Companies, to
Snyder, R. B., Midwest Research Institute. March 16, 1993.
Costs for SCR systems applied to reciprocating engines.
23. Letter and attachments from Becquet, J., Kleenaire Division
of Encore Environmental Consulting and Remediation, to
Snyder, R. B., Midwest Research Institute. March 25, 1993.
24. Minutes of meeting dated February 5, 1992 with
representatives of the Industrial Gas Cleaning Institute,
U. S. Environmental Protection Agency, and Midwest Research
Institute. December 18, 1991. Selective catalytic
reduction.
25. Letter from Sparks, J. S., Atlas-Steuler Division of Atlas
Minerals and Chemicals, Incorporated, to Snyder, R. B.,
Midwest Research Institute. March 30, 1993. SCR system
information for reciprocating engines.
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7.0 ENVIRONMENTAL AND ENERGY IMPACTS
This chapter presents environmental and energy impacts for
the NOX emission control techniques described in Chapter 5. These
control techniques are air-to-fuel ratio (A/F) adjustment,
ignition timing retard, a combination of A/F adjustment and
ignition timing retard, prestratified charge (PSC®), nonselective
catalytic reduction (NSCR), selective catalytic reduction (SCR),
and conversion to low-emission combustion. The impacts of the
control techniques on air pollution, solid waste disposal, and
energy consumption are discussed in this chapter.
This chapter is organized in three sections. Section 7.1
presents air pollution impacts; Section 7.2 presents solid waste
impacts; and Section 7.3 presents energy consumption impacts.
7.1 AIR POLLUTION
Applying the control techniques discussed in Chapter 5
reduces NOX emissions from spark-ignited (SI) and compression-
ignited (CD engines. The tables in this section present
uncontrolled NOX emissions, percent NOX reduction, controlled NOX
emissions, and annual NOX removed for each control technique.
Since the applicable control techniques vary by type of engine,
tables in this section are organized by engine type.
Furthermore, the tables presented in this section are for
continuous-duty engines operating at 8,000 hours per year
(hr/yr). Nitrogen oxide emission reductions for engines
operating at reduced annual capacity levels would be calculated
by prorating the NOX reductions shown in these tables.
7.1.1 NOX Emission Reductions for Rich-Burn SI Engines
The available control techniques for rich-burn SI engines
(discussed in Section 5.1) are A/F adjustment, ignition timing
retard, a combination of A/F adjustment and ignition timing
7-1
-------
retard, PSC®, NSCR, and low-emission combustion. The achievable
NOX emission reductions for these control techniques are shown in
Table 7-1 for rich-burn engines with power outputs ranging from
80 to 8,000 hp. Air-to-fuel ratio adjustment or ignition timing
retard results in the lowest (20 percent) NOX emission
reductions, each achieving a reduction in NOX emissions for
engines operating in continuous-duty applications from
2.23 tons/yr for the smallest engine (80 hp) to 222 tons/yr for
the largest engine (8,000 hp). The greatest NOX emission
reductions are achieved by NSCR. For a 90 percent NO., reduction
J\. •
efficiency, NSCR achieves NOX reductions ranging from 10 tons/yr
for the smallest continuous-duty engine (80 hp) to 1,000 tons/yr
for the largest continuous-duty engine (8,000 hp).
7.1.2 NO.. Emission Reductions for Lean-Burn SI Engines
Jt
The available control techniques for lean-burn SI engines
(discussed in Section 5.2) are A/F adjustment, ignition timing
retard, a combination of A/F adjustment and ignition timing
retard, SCR, and low-emission combustion. Table 7-2 presents the
achievable NOX emission reductions for these control techniques.
For lean-burn engines, ignition timing retard results in the
lowest (20 percent) NOX emission reductions. For continuous-duty
engines, NOX reductions range from 3.0 tons/yr for the smallest
engine (200 hp) to 118 tons/yr for the largest engine (8,000 hp).
For a 90 percent NOV reduction efficiency, SCR achieves the
JC
highest NOX reductions, ranging from 26.6 tons/yr for the
smallest continuous-duty engine (200 hp) to 1,060 tons/yr for the
largest continuous-duty engine (8,000 hp).
7.1.3 NO Emission Reductions for Diesel CI Engines
The available control techniques for diesel CI engines are
ignition timing retard and SCR. These control techniques are
discussed in Section 5.3.1. The achievable NCL. reductions are
Jv
presented in Table 7-3. Ignition timing retard has the lowest
NO., reduction efficiency (25 percent), removing 2.11 tons/yr for
Jt
the smallest continuous-duty engine (80 hp) to 211 tons/yr for
the largest continuous-duty engine (8,000 hp). Selective
catalytic reduction provides the greatest. NOX reduction
7-2
-------
TABLE 7-1. RICH-BURN SI ENGINES
Power
output, HP
80
80
80
80
80
80
150
150
150
150
150
250
250
250
250
250
250
350
350
350
350
350
350
500
500
500
500
500
500
650
650
650
650
650
650
850
850
850
850
850
850
1200
1200
1200
1200
1200
1200
1600
1600
1600
1600
1600
1600
Uncontrolled
NOY, tons/yr
11.1
11.1
11.1
11.1
11.1
11.1
20.9
20.9
20.9
20.9
20.9
34.8
34.8
34.8
34.8
34.8
34.8
48.7
48.7
48.7
48.7
48.7
48.7
69.6
69.6
69.6
69.6
69.6
69.6
90.5
90.5
90.5
90.5
90.5
90.5
118
118
118
118
118
118
167
167
167
167
167
167
223
223
223
223
223
223
Control technique
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC«
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
Percent NOX
reduction
20
20
30
87
90
87
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
Controlled
NO,, tons/yr
8.9
8.9
7.8
1.4
1.1
1.4
16.7
14.6
2.6
2.1
2.6
27.8
27.8
24.4
4.4
3.5
4.4
39.0
39.0
34.1
6.2
4.9
6.2
55.7
55.7
48.7
8.8
7.0
8.81
72.4
72.4
63.3
11.5
9.1
11.5
94.7
94.7
82.8
15.0
11.8
15.0
134
134
117
21.1
16.7
21.1
178
178
156
28.2
22.3
28.2
NOX removed,
tons/yr
2.2
2.2
3.3
9.7
10
9.7
4.2
6.3
18.2
18.8
18.2
7.0
7.0
10.4
30.4
31.3
30.4
9.7
9.7
14.6
42.6
43.9
42.6
13.9
13.9
20.9
60.8
62.6
60.8
18.1
18.1
27.1
79.0
81.4
79.0
23.7
23.7
35.5
103
106
103
33.4
33.4
50.1
146
150
146
44.5
44.5
66.8
195
200
195
7-3
-------
TABLE 7-1. (continued)
Power
output, HP
2000
2000
2000
2000
2000
2000
2500
2500
2500
2500
2500
2500
4000
4000
4000
4000
4000
4000
6000
6000
6000
6000
6000
6000
8000
8000
8000
8000
8000
8000
Uncontrolled
NOT, tons/yr
278
278
278
278
278
278
348
348
348
348
348
348
557
557
557
557
557
557
835
835
835
835
835
835
1,110
1,110
1,110
1,110
1,110
1,110
Control technique
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC«
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC*
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC«
NSCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
PSC«
NSCR
Low-Emission Combustion
Percent NOX
reduction
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
20
20
30
87
90
87
Controlled
NOY, tons/yr
223
223
195
35.2
27.8
. 35.2
278
278
244
44.1
34.8
44.1
445
445
390
70.5
55.7
70.5
668
668
585
106
83.5
106
888
888
777
141
111
141
NOX removed,
tons/yr
55.7
55.7
83.5
243
251
243
69.6
69.6
104
304
313
304
HI
111
167
486
501
486
167
167
251
730
752
730
222
222
333
969
999
969
7-4
-------
TABLE 7-2. LEAN-BURN SI ENGINES
Power
output, HP
200
200
200
200
200
350
350
350
350
350
550
550
550
550
550
800
800
800
800
800
1350
1350
1350
1350
1350
1550
1550
1550
1550
1550
2000
2000
2000
2000
2000
2500
2500
2500
2500
2500
3500
3500
3500
3500
3500
5500
5500
5500
5500
5500
8000
8000
8000
8000
8000
Uncontrolled
NOV, tons/yr
29.6
29.6
29.6
29.6
29.6
51.8
51.8
51.8
51.8
51.8
81.4
81.4
81.4
81.4
81.4
118
118
118
118
118
200
200
200
200
200
229
229
229
229
229
296
296
296
296
296
370
370
370
370
370
518
518
518
518
518
814
814
814
814
814
1,180
1,180
1,180
1,180
1,180
Control technique
A/F Adjustment
IT Rettrd
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
A/F Adjustment
IT Retard
A/F & IT Adjustment
SCR
Low-Emission Combustion
Percent NOX
reduction
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
20
10
25
90
88
Controlled NOX,
tons/yr
23.7
26.6
22.2
3.0
3.5
41.4
46.6
38.9
5.2
6.2
65.1
73.3
61.1
8.1
9.69
94.7
107
88.8
11.8
14.1
160
180
150
20.0
23.8
184
206
172
22.9
27.3
237
266
222
29.6
35.2
296
333
278
37.0
44.1
414
466
389
51.8
61.7
651
733
611
81.4
96.9
944
1,060
885
120
141
NOX removed,
tons/yr
5.9
3.0
7.4
26.6
26.1
10.4
5.2
13.0
46.6
45.6
16.3
8.1
20.4
73.3
71.7
23.7
11.8
29.6
107
104
40.0
20.0
50.0
180
176
45.9
22.9
57.4
206
202
59.2
29.6
74.0
266
261
74.0
37.0
92.5
333
326
104
51.8
130
466
456
163
81.4
204
733
717
236
118
295
1,060
1,040
7-5
-------
TABLE 7-3.
NOX EMISSION REDUCTIONS FOR DIESEL CI ENGINES
Power
output, HP
80
80
80
150
150
150
250
250
250
350
350
350
500
500
500
700
700
700
900
900
900
1100
1100
1100
1400
1400
1400
2000
2000
2000
2500
2500
2500
4000
4000
4000
6000
6000
6000
8000
8000
8000
Uncontrolled
NOX, tons/yr
8.46
8.46
8.46
15.9
15.9
15.9
26.4
26.4
26.4
37.0
37.0
37.0
52.9
52.9
52.9
74.0
74.0
74.0
95.2
95.2
95.2
116
116
116
148
148
148
211
211
211
264
264
264
423
423
423
634
634
634
846
846
846
Control technique
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
IT Retard
SCR (base metal)
SCR (zeolite)
Percent NOX
reduction
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
25
80
90
Controlled
NOX, tons/yr
6.3
1.7
0.85
11.9
3.2
1.6
19.8
5.3
2.6
27.8
7.4
3.7
39.6
10.6
5.3
55.5
14.8
7.4
71.4
19.0
9.5
87.2
23.3
11.6
111
29.6
14.8
159
42.3
21.1
198
52.9
26.4
317
84.6
42.3
476
127
63.4
634
169
84.6
NOX removed,
tons/yr
2.1
6.8
7.6
4.0
12.7
14.3
6.6
21.1
23.8
9.3
29.6
33.3
13.2
42.3
47.6
18.5
59.2
66.6
23.8
76.1
85.6
29.1
93.0
105
37.0
118
133
52.9
169
190
66.1
211
238
106
338
381
159
507
571
211
677
761
7-6
-------
efficiency (90 percent) for continuous-duty engines and removes
from 7.61 tons/yr (for the smallest engine [80 hp]) to
761 tons/yr (for the largest engine [8,000 hp]) of NOX emissions.
Zeolite catalyst vendors quote a 90 percent NOX reduction
efficiency; base-metal catalyst vendors quote either 80 or
90 percent. For this reason, NOX reduction levels are shown for
both 80 and 90 percent in Table 7-3.
7.1.4 NQX Emission Reductions for Dual-Fuel CI Engines
The available control techniques for dual-fuel engines are
ignition timing retard, SCR, and low-emission combustion. These
controls are discussed in Section 5.3.2 and are shown in
Table 7-4. Ignition timing retard has the lowest NOX reduction
efficiency (20 percent), removing 10.5 tons/yr for the smallest
continuous-duty engine (700 hp) to 120 tons/yr for the largest
continuous-duty engine (8,000 hp). Selective catalytic reduction
has the highest reduction efficiency (90 percent), removing
47.2 tons/yr for the smallest continuous-duty engine (700 hp) to
539 tons/yr for the largest continuous-duty engine (8,000 hp).
7.1.5 Emissions Trade-offs
Control techniques that modify combustion conditions to
reduce the amount of NOX formed may also increase the amounts of
CO and unburned HC emissions produced. Also, SCR produces
ammonia emissions. These air pollution impacts are discussed in
the following two sections.
7.1.5.1 Impacts of Combustion Controls on CO and HC
Emissions. As discussed in Chapter 5, reducing NOX emission
levels may increase CO and HC emissions. Table 7-5 shows the
effect on CO and HC emissions of various control techniques on
all engine types. For rich-burn engines, CO and HC emissions
increase for most control techniques used. Emissions of CO
increase sharply at fuel-rich A/F's due to the lack of oxygen to
fully oxidize the carbon. As the A/F increases toward fuel-lean
conditions, excess oxygen is available and CO emissions decrease
as essentially all carbon is oxidized to C02. Emissions of HC
increase at fuel-rich A/F's because insufficient oxygen levels
inhibit complete combustion.
7-7
-------
TABLE 7-4. DUAL-FUEL CI ENGINES
Power
output, HP
700
700
700
900
900
900
1650
1650
1650
2200
2200
2200
3000
3000
3000
5000
5000
5000
8000
8000
8000
Uncontrolled
NOX, tons/yr
52.4
52.4
52.4
67.4
67.4
67.4
124
124
124
165
165
165
225
225
225
374
374
374
599
599
599
Control technique
IT Retard
SCR
Low-Emission Combustion
IT Retard
SCR
Low-Emission Combustion
IT Retard
SCR
Low-Emission Combustion
IT Re*ard
SCR
Low-Emission Combustion
IT Retard
SCR
Low-Emission Combustion
IT Retard
SCR
Low-Emission Combustion
IT Retard
SCR
Low-Emission Combustion
Percent NOX
reduction
20
90
76
20
90
76
20
90
76
20
90
76
20
90
76
20
90
76
20
90
76
Controlled
NOX, tons/yr
41.9
5.2
12.3
53.9
6.7
15.9
98.9
12.4
29.1
132
16.5
38.8
180
22.5
52.9
300
37.4
88.1
479
60.0
141
NOX removed,
tons/yr
10.5
47.2
40.1
13.5
60.7
51.5
24.7
111
94.5
33.0
148
126
44.9
202
172
74.9
337
286
120
539
458
7-8
-------
TABLE 7-5.
EFFECTS OF NOX CONTROL TECHNIQUES ON CO AND
HC EMISSIONS
Engine type Control technique
Rich-Burn SI A/F Adjustment
IR Retard
A/F and IR Adjustments
PSC
NSCR
Low-Emission Combustion
Lean-Burn SI A/F Adjustment
IR Retard
A/F and IR Adjustments
SCR
Low-Emission Combustion
Diesel CI IR Retard
SCR
Dual-Fuel CI IR Retard
SCR
Low-Emission Combustion
Effect on CO emissions
increase
(1 to 33 g/hp-hr)
minimal
increase*
increase
C<.3.0 g/hp-hr)
increase
C<37 g/hp-hr)b
increase
C<3.5 g/hp-hr)
minimal
minimal
minimal1
minimal
increase
(<.3.5 g/bp-hr)
variedd
minimal
increase
(13 to 23 percent)
minimal
varied'
Effect on HC emissions
increase
(0.2 to 0.3 g/hp-hr)
minimal
increase8
increase
(<2.0 g/hp-hr)
minimal0
C<3.3 g/hp-hr)
increase
C<2.0 g/hp-hr)
slight increase
minimal
mmimala
minimal
increase
(<2.0 g/hp-hr)
varied6
minimal
increase
(6 to 21 percent)
mjnimal
varied
aThe increase is expected to be less than that shown for A/F adjustment.
From VCAPCD data base, consistent with 4,500 ppmv CO emission limit.
cAccording to a VCAPCD test report summary.
Ranged from a 13.2 percent decrease to a 10.8 percent increase for limited test results.
Ranged from a 0 to 76.2 percent increase for limited test results.
'May be slight increase or decrease, depending on engine model and manufacturer.
7-9
-------
Control techniques used on lean-burn engines to reduce NOY
J\.
generally have less effect on CO and HC emissions. At fuel-lean
A/F's, CO and HC emissions increase slightly as excess oxygen
cools combustion temperatures and inhibits complete combustion.
While it is unclear what effect ignition timing retard has on CO
and HC emissions for diesel engines (see Section 5.3.1.1), SCR
has a minimal effect on these emissions. For dual-fuel engines,
ignition timing retard increases CO and HC emissions, while SCR
has little effect on CO and HC emissions.
As NOX control techniques increase CO and HC emissions to
unacceptable levels, an oxidation catalyst can be used to reduce
these emissions. The oxidation catalyst is an add-on control
device that reduces CO and HC emissions to C02 and H20. This
reaction is spontaneous in the presence of the catalyst but
requires excess oxygen in the exhaust. For this reason, air may
need to be injected into the exhaust upstream of the oxidation
catalyst for rich-burn engines, especially for rich-burn engines
operating with an NSCR system to reduce NOX emission.
7.1.5.2 Ammonia Emissions from SCR. The SCR process
reduces NOX emissions by injecting ammonia (N^) into the flue
gas. The ammonia reacts with NOX in the presence of a catalyst
to form water and nitrogen. The NO., removal efficiency of this
Jv
process is partially dependent on the NH3/NOX ratio. Increasing
this ratio reduces NOX emissions but increases the probability of
passing unreacted ammonia through the catalyst unit into the
atmosphere (known as ammonia "slip"). Although some ammonia slip
is unavoidable because of ammonia injection control limitations
and imperfect distribution of the reacting gases, a properly
designed SCR system will limit ammonia slip to less than 10 ppmv
for base-load applications. Ammonia injection controls for
variable-load applications have limited experience to date, and
ammonia slip levels may be higher for variable or cyclical-load
applications.1
7-10
-------
7.2 SOLID WASTE DISPOSAL
Catalytic materials used in SCR and NSCR systems have a
finite life, and the spent catalyst material must be disposed of
or recycled. Most catalyst suppliers accept return of spent
catalyst materials.1
While spent precious metal and zeolite catalysts are not
considered hazardous waste, it has been argued that vanadium- and
titanium-based catalysts are classified as hazardous waste and
therefore must be handled and disposed of in accordance with
hazardous waste regulations. According to the Best Demonstrated
Available Technology (BDAT) Treatment Standards for Vanadium P119
and P120, spent catalysts containing vanadium pentoxide are not
classified as hazardous waste.
State and local agencies are authorized to establish their
own hazardous waste classification criteria, however, and spent
catalyst material may be classified as a hazardous material in
some areas. For example, the State of California has reportedly
classified spent catalyst material containing vanadium pentoxide
as a hazardous waste.3
7.3 ENERGY CONSUMPTION
Fuel consumption increases as a result of some control
techniques used to reduce NOX emissions. In particular, those
techniques that adjust operating or combustion parameters often
increase BSFC. These increased fuel consumptions, where
applicable, are discussed in Chapter 5 and are summarized in
Table 7-6.
Some control techniques may reduce the power engine output
due to lower fuel input to the engine caused by lean A/F's, or
increased backpressure on the engine caused by placement of a
catalyst in the exhaust. Although this reduction in power output
produces lower NOX emissions for the plant, the lost power must
be produced by another source, such as a utility. Increased NOX
emissions may result at these alternative power sources. These
reductions in power output, where applicable, are discussed in
Chapter 5 and are summarized in Table 7-6.
7-11
-------
TABLE 7-6
EFFECTS OF NOX CONTROL TECHNIQUES
AND POWER OUTPUT
ON FUEL CONSUMPTION
Engine type
Rich-bum SI
Lean-bum SI
Diesel CI
Dual Fuel CI
Control technique
A/F Adjustment
IR Retard
A/F and IR
Adjustments
PSC
NSCR
Low-Emission
Combustion
A/F Adjustment
IR Retard
A/F and IR
Adjustments
SCR
Low-Emission
Combustion
IR Retard
SCR
IR Retard
SCR
Low-Emission
Combustion
Fuel consumption
0-5 percent increase
0-7 percent increase
0-7 percent increase
2 percent increase
0-5 percent increase
variable6
0-5 percent increase
0-5 percent increase
0-5 percent increase
0.5 percent increase
variable6
0-5 percent increase
0.5 percent increase
0-3 percent increase
0.5 percent increase
0-3 percent increase
Effect on power output*
none"
none
minimal0
5-20 percent reduction
1-2 percent reduction
none
none
none
minimalc
1-2 percent reduction
none
none
1-2 percent reduction
none
1-2 percent reduction
none
aAt rated load.
Severe adjustment or retard may reduce power output.
cOne source reported a 5 percent power reduction at rated load (Reference 4).
''Power reduction associated with backpressure on the engine created by a catalyst. Fuel-rich adjustment for
NSCR operation may offset this power reduction.
^In most engines, the effect is a decrease in fuel consumption of 0-5 percent.
7-12
-------
Furthermore, for SCR units, additional electrical energy is
required to operate ammonia pumps and ventilation fans. This
energy requirement, however, is believed to be small and is not
included in this analysis.
7.4 REFERENCES FOR CHAPTER 7
1. Letter and attachments from Smith, J. C., Institute of Clean
Air Companies, to Neuffer, W. J., EPA/ISB. May 14, 1992.
Use of catalyst systems with stationary combustion sources.
2. 55 FR 22576. June 1, 1990.
3. M. Schorr. NOX Control for Gas Turbines: Regulations and
Technology. General Electric Company, Schenectady, NY.
Presented at the Council of Industrial Boiler Owners NOX
Control IV Conference, February 11-12, 1991. pp. 3-5.
4. Letter from Eichamer, P. D., Exxon Chemical Company,
Baytown, TX, to Snyder, R. B., Midwest Research Institute.
June 24, 1992. Engine adjustments for NOX control.
7-13
-------
APPENDIX A
This appendix contains a summary of emission tests conducted
on reciprocating engines in Ventura County, California. The
summary was compiled from a data base provided by the Ventura
County Air Pollution Control District (VCAPCD).1 The data are
tabled by control technique as follows:
Table A-l:
Table A-2:
Table A-3:
Table A-4:
Table A-5:
Prestratified charge (PSC®);
Nonselective catalytic reduction (NSCR);
Low-emission combustion, rich-burn engines;
Low-emission combustion, lean-burn engines; and
Selective catalytic reduction (SCR).
An explanation of the table entries and abbreviations is given
below:
Engine No.:
Test No.:
Manufacturer:
Model:
Test date:
Status:
Each engine is given a specific number, assigned
by VCAPCD.
For those tables in which this column appears,
this number corresponds to the number of emission
tests performed on the engine. This number was
added to the data base provided by VCAPCD.
The engine manufacturer as listed in the data
base.
The engine model as listed in the data base.
Date of the test as listed in the data base.
The status of the engine, as listed in the data
base. The key for this column is:
A-l
-------
c- controlled and currently operating (at the time
the database was received)
d- deleted, removed from service
e- exempt from Rule 74.9
m- deleted, but electrified in Southern California
Edison's incentive program
s- standby
Emissions: Emission levels, as reported in the database in
ppmv, referenced to 15 percent oxygen.
A-2
-------
TABLE A-1 VENTURA COUNTY APCOEMISSON DATABASE FOAPSCCONTTOL FORC ENGINES.
Engina
No
1
2
2
2
3
3
3
3
4
4
4
4
4
4
5
9
5
8
8
7
7
7
7
7
8
8
10
10
10
10
10
10
10
11
11
11
11
12
12
12
12
12
12
12
13
13
13
13
13
13
14
14
14
14
19
19
15
18
Manufacture
Waukaaha
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Waukaaha
Waukaaha
Waukaaha
Waukaana
Waukaaha
Waukaaha
Waukaana
Waukaaha
Waukaaha
Waukaaha
Ingaraoll-Rand
Ingaraoll-Rand
Ingaraoll-Rand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll-Rand
Ingaraoll-Rartd
Ingaraoil-nand
Ingaraoll-Rand
Ingaraoll-Rand
Ingaraoll-Rand
Ingaraoll Rand
Ingaraoll-nand
Ingaraoll-Rand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll-Rand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll-Rand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll nand
Ingaraoll-nand
Ingaraoll-nand
Ingaraoll-nand
IngaraoH-nand
Ingaraoll-nand
Ingaraoll'fland
Ingaraorl Hand
Ingaraoll Band
Ingaraoll-nand
Ingaraoll nand
1400Z
O378
Q376
Q376
G376
G378
G378
G378
G376
Q379
O379
Q378
0378
O378
P9360G
P9360G
P8360G
P8380G
P6360G
P6390G
P6360G
P9390G
P9390G
P9390G
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
Ingaraoll
InQaMVOlr
SVO-8
svG-e
ind
IngaraoU-nand
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
CaterpiHar
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
8VG-6
Q398
O398
0398
O398
Q368
0368
F817GU
F817GU
F817GU
FS17GU
F817QU
F817GU
F817GU
145GZU
118
330
330
330
330
330
330
330
330
330
330
330
330
330
800
800
BOO
800
800
800
800
768
800
768
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
44O
440
440
412
412
412
412
412
412
180
180
160
180
180
160
180
100
Taat
date
12/21/86
08/27/88
07/28/92
12/12/81
03/23/87
07/29/92
08/27/89
11/24/88
06/27/88
07/29/62
09715/60
12/12/81
03/03/88
03/23/87
08/27/86
10/20/87
07/30/92
08/27/88
07/30/92
05/15/90
08727/86
12/29/87
07/30/82
03/24/87
09/20/88
07/17/60
12/21/88
03/20/80
06/14/88
12/13/88
08/24/81
12/03/81
04/18/88
05/24/88
05/17/88
02/22/88
07/17/80
12/21/88
08/20/88
04/15/88
02/22/88
05/17/88
la/OS/el
06/24/81
05/24/88
12/13/88
08/14/88
06/14/88
12/21/88
04/18/86
05/17/89
06/24/88
02/22/89
06/20/86
07/17/90
12/03/81
06/24/81
12/21/88
02/22VW
06/20/86
09/18/88
06/14/88
05/17/90
03/03/89
10/19/60
12/19/91
01/30/89
12/28/87
12/01/88
12/10/87
01/06/92
12/13/88
12/13/86
01/06/92
12/01/88
10/14/86
Statua
NOx
PSCOfl
840
0
0
854
14
0
0
44
0
0
0
892
14
23
0
44
0
0
0
0
0
36
0
845
814
814
87
814
28
814
814
814
78
17
814
814
1428
53
1428
78
1426
1428
1428
1428
41
1428
10
21
34
88
1060
81
1080
1060
681
681
681
681
86
78
1281
1281
1281
88
70
0
877
0
0
787
462
30
27
0
0
0
0
41
24
24
24
37
83
14
26
42
44
43
33
36
88
14
23
43
44
23
16
33
20
22
36
26
90
49
92
87
31
28
87
14
72
78
17
44
20
45
53
37
78
34
98
87
48
41
77
10
21
34
88
22
81
28
88
83
18
90
82
86
78
87
87
94
88
70
74
43
21
40
48
49
30
27
29
38
45
37
41
24
ptrovni **•
^•fcvnt
•ducDOfl
•7
0
0
83
0
0
0
0
0
0
0
92
0
0
0
0
0
0
0
0
0
0
0
94
94
94
0
M
0
82
86
81
0
0
89
ae
87
0
87
0
ae
68
83
87
0
85
0
0
0
0
86
0
88
84
80
ee
89
84
0
0
85
83
83
0
0
0
84
0
0
84
81
0
0
0
0
0
0
0
0
CO
PSCOfl
NA
MA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
PSCOn
77
138
187
122
231
212
192
193
139
161
179
108
188
172
83
114
143
89
149
118
84
180
133
141
77
ee
98
128
82
78
98
88
28
72
0
0
129
100
120
43
0
0
279
191
47
82
70
70
87
49
0
43
0
88
lie
108
170
109
89
80
0
83
0
78
89
1087
307
408
1988
197
293
209
184
178
238
247
224
189
18774
NMHC
PSCCXf
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
PSCOn
89
40
204
9
98
180
84
102
28
329
0
4
83
22
78
18
11
18
19
0
13
21
9
17
0
0
24
0
0
0
0
0
0
0
0
0
0
7
0
0
0
0
0
0
0
0
0
0
14
0
0
0
0
0
0
0
0
0
0
38
0
0
0
0
0
229
88
33
19
0
389
14
91
4
16
18
9
9
98
A-3
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
3
5
15
16
16
38
81
81
81
81
81
81
81
81
81
81
81
81
83
83
83
83
83
83
83
83
83
83
83
83
84
84
84
84
84
84
84
84
84
84
84
84
64
85
85
85
85
85
85
85
85
85
85
65
85
85
87
87
87
87
Manufacturer
biriMmnl D^nr!
mgeraoi-Hend
Ingaraof-Rand
CeterpWar
Caterpillar
Waukeaha
Waukeaha
Caterpillar
Waukeaha
Waukeaha
Waukeaha
Waukaaha
Waukeaha
Waukeaha
Waukaaha
Waukeaha
Waukeaha
Waukeaha
Waukeaha
Waukaaha
Waukeaha
Waukeaha
Waukaaha
Waukaaha
Waukaaha
Waukeaha
Waukeaha
Waukaaha
Waukeaha
Waukaaha
Waukaaha
Waukeaha
Waukeaha
Waukeaha
Waukesha
Waukeaha
Waukaaha
Waukeaha
Waukaaha
Waukaaha
Waukaaha
Waukeaha
Waukeaha
Waukaaha
Waukaaha
Waukeaha
Waukaaha
Waukaaha
Waukeaha
Waukeaha
Waukeaha
Waukaaha
Waukeaha
Waukeaha
Waukeaha
Waukaaha
Waukaaha
Waukeaha
Waukaaha
Waukaaha
Waukeaha
Waukaaha
Model
iun_£
jvo-e
JVG-8
Q379
O3306
F3521Q
F3521Q
O353
L7042Q
L7042Q
L7042O
L7042Q
L7042G
L7042O
L7042Q
L7042Q
L70420
L7042Q
L7042G
L7042G
L7042O
L7042O
L7042Q
L7042G
L70420
L70420
L7042G
L70420
L7042Q
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042O
L7042G
L7042O
L7042G
L7042G
L7042G
L70420
L7042G
L70420
L7042G
L7042O
L7042G
L7042O
L70420
L7042G
L7042G
L7042G
Power
(hp)
4 AK
165
225
295
67
391
391.
250
858
858
775
775
775
858
775
775
775
775
775
775
858
858
775
775
775
858
775
775
775
775
775
775
513
858
775
775
775
775
775
775
775
775
775
775
775
858
858
775
775
775
775
775
775
775
775
775
775
775
775
775
858
775
Test Status
data
/V8 lf\A MB
03/04/86
12/10/87
12/10/87
12/11/89
06/11/90
12/11/89
03/27/92
02/04/87
05/27/87
10/19/87
12/08/87
03/22/88
06/29/88
03/30/89
06/05/89
09/13/89
12/12/89
03/05/90
04/09/90
03/10/87
05/27/87
09/22/87
12/08/87
03/22/88
06/29/88
03/30/89
06/05/89
09/13/89
12/12/89
03/09/90
06/19/92
02/24/87
05/29/87
09/22/87
12/08/87
03/22/88
06/29/88
03/31/89
06/05/89
09/14/89
12/28/89
03/05/90
04/09/90
06/06/90
02/09/87
05/29/87
09/22/87
12/06/87
03/22/88
06/29/88
03/31/89
06/05/89
09/14/89
12/28/89
03/05/90
04/09/90
06/19/92
03/31/89
06/19/92
05/29/87
06/06/90
c
c
c
c
c
c
c
c
c
c
c
c
c
e
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
e
c
c
c
Emiaaiona,
NOx
Unoontr.
Mm^
457
564
786
393
496
174
0
1074
891
635
769
2563
1231
501
448
458
513
565
425
616
583
630
764
2417
2257
71
52
626
619
640
0
970
839
620
694
2147
2338
495
337
363
372
442
360
407
1204
691
576
714
2432
2189
252
210
185
254
243
565
0
144
0
333
0
pprnv at to 15 percent oxygen
O^Mt^M*
I^VrCVru
Contr. reduction
»«h »
32
31
23
22
4
29
16
18
1
16
56
61
16
8
21
5
38
6
43
45
53
50
166
197
10
4
5
67
46
3
8
3
20
22
43
45
21
11
12
17
9
20
13
5
11
15
6
150
28
12
5
2
4
15
44
19
3
32
27
15
V*
94
96
94
98
98
0
99
97
100
98
98
96
99
96
95
99
93
99
93
92
92
94
93
91
87
92
99
89
93
0
99
100
97
97
96
98
96
97
97
96
98
94
97
100
98
97
99
94
99
95
97
99
98
94
91
0
98
0
92
92
CO
2067
2455
1061
5241
3402
11045
65
2819
433
3469
132
201
1359
1574
2712
3269
2848
1796
3906
2079
886
2158
859
156
617
11834
11569
403
993
1045
2003
4165
57
1347
777
1838
2143
492
5968
4946
4797
5282
4359
1412
3247
1080
1141
111
1135
2517
6411
8113
8453
7240
9624
734
1988
9772
2922
6085
1412
NMHC
28
24
53
22
23
30
0
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
185
12
0
0
0
0
0
0
0
0
0
0
0
0
21
0
0
0
0
0
0
0
0
0
0
0
694
0
341
0
0
A-4
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
87
87
87
87
87
87
87
87
87
87
87
90
90
90
90
90
90
90
90
90
90
90
90
90
90
122
123
130
130
130
130
130
153
153
153
153
153
153
153
153
156
156
156
156
156
156
206
206
206
206
206
206
206
207
207
207
207
207
207
208
208
Manufacturer
Waukaaha
Waufceeha
Waukaaha
Waukaaha
Waukaeha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
WaukMha
Waukaaha
Waukaaha
Waukasha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Minnaapolia-Mol
Minnaapolia-Mol
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
White Superior
White
White Superior
White
White Superior
White
White
White
White Superior
White Superior
White
White
JAflilfca
wnn*
White Superior
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Modal
L7042Q
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
800-6A
800-6A
G342
G342
G342
G342
G342
G-8258
G-8258
G-8258
G-8258
G-8258
08258
G-8258
G-8258
0-8258
G-8258
G-8258
G-8258
G-8258
08258
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
Power
(hp)
858
775
775
775
775
775
775
858
775
775
775
775
775
775
775
775
858
775
775
775
858
775
775
858
775
80
80
225
225
225
225
225
625
625
625
625
625
625
625
625
625
625
625
625
625
625
1250
1250
1250
1250
1250
1250
1250
1250
1250
1250
1250
1250
1250
1250
1250
Test Status
date
06/29/86
06/05/89
09/14/89
12/28/89
03/22/88
09/22/87
03/09/90
03/10/87
12/06/87
04/09/90
06/29/88
12/08/87
06/29/88
03/22/88
09/22/87
06/19/92
03/10/87
06/05/89
03/09/90
03/09/90
05/28/87
09/13/89
03/31/89
06/29/88
12/12/69
07/13/92
06/23/92
07/28/92
12/19/87
08/09/90
10/04/89
08/03/88
12/04/86
03/23/89
08/03/88
08/09/90
10/19/87
07/28/92
08/15/90
10/02/89
08/03/88
10/19/87
08/09/90
07/28/92
10/02/89
12/04/86
12/01/87
02/22/88
08/06/90
07/29/92
10/06/89
08/02/88
03/22/89
07/29/92
08/06/90
08/01/88
10/07/89
12/11/87
02/22/88
02/22/88
03/23/89
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
Emiaaiona,
NOx
Unoontr.
780
116
103
127
717
280
560
235
255
496
780
766
2114
2094
531
0
345
380
410
699
677
285
394
2114
439
0
0
395
436
566
618
443
497
268
248
1765
108
362
1052
451
507
324
333
666
390
478
572
2005
554
694
613
318
215
497
676
426
564
711
1799
635
845
ppmv at to 1 5 percent oxygen
Paroant
Corrtr. reduction
37
6
5
11
57
18
47
11
23
21
37
17
30
35
8
10
38
7
11
17
2
10
6
30
7
13
6
1
2
15
17
13
22
8
2
2
12
12
1
46
36
38
35
18
39
19
39
114
31
44
44
26
40
18
62
28
42
23
84
56
49
95
95
95
91
92
94
91
95
91
96
95
98
99
98
99
0
89
98
97
97
100
96
96
99
99
0
0
100
100
97
97
97
96
97
99
100
89
97
100
90
93
88
89
97
90
96
93
94
94
94
93
92
81
96
91
93
93
97
95
91
94
CO
8396
11607
10784
12472
7517
10625
2124
9662
7488
3098
8396
224
703
1085
2822
795
OOOv
5764
6253
713
606
5342
5503
703
2549
56
565
3183
4991
2114
910
0
3883
6708
0
1456
0
2588
2599
4057
0
0
2250
3682
3799
3954
3566
0
2244
748
3681
0
0
902
3980
0
3808
3118
0
0
1260
NMHC
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
308
0
0
0
0
0
0
0
0
0
29
1
31
26
11
0
0
6
0
0
9
0
7
8
5
0
0
10
4
6
5
37
0
22
24
29
0
0
33
38
0
21
38
0
0
0
A-5
-------
TABLE A-2. VENTURA COUNTY APCO EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
208
206
206
206
233
233
233
234
234
234
239
239
240
240
240
240
241
241
241
241
241
294
294
294
294
294
294
294
294
294
294
294
303
303
303
303
303
303
303
303
303
303
303
303
303
303
303
304
304
304
304
304
304
304
304
304
304
304
306
305
305
Atanutectur*
Waukeeha
Waukeeha
Waukeeha
Waukeehe
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Caterpillar
dtorpHtar
Caterpillar
CeterpKar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Waukeehe
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Mod*
L7042Q
L7042G
L7042Q
L7042G
F1197Q
H2476Q
F11970
F1197Q
F1197Q
H2476Q
Q398
Q398
G396
O398
0398
G398
Q398
0396
O396
O396
0396
L5790Q
L5790Q
L5790Q
L5790O
L5790Q
L5790Q
L5790G
L5790Q
L5790Q
L5790O
L5790Q
F1197O
F1197Q
F1197O
F11970
F11970
F1197G
F11970
F1197O
F1197G
F1197G
F1197G
F1197G
F1197Q
F1197G
F1187G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
Power
(hp)
1250
1250
1250
1250
186
186
186
186
186
186
412
412
412
412
412
412
412
412
412
412
412
736
738
738
738
736
736
738
738
738
738
738
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
Tast Status
date
08/02/88
12/01/87
07/29/92
06/06/90
05/22/90
09/19/89
03/10/92
OS/22/90
03/11/92
09/19/89
07/06/89
05/11/90
04/26/88
12/19/91
05/11/90
12/07/90
04/26/86
12/19/91
10/19/90
05/11/90
07/27/88
11/14/88
06/20/90
09/18/87
11/17/89
08/31/89
06/23/88
01/15/86
12/02/91
03/11/92
09/09/88
06/21/89
06/19/89
06/05/92
12/10/91
11/30/89
05/21/90
10/28/86
02/19/87
09/30/87
02/14/89
08/29/90
09/08/88
03/18/88
09/08/89
02/28/90
01/19/88
06/05/92
06/19/89
12/10/91
11/30/89
09/08/88
05/21/90
01/19/88
03/30/88
08/29/90
02/28/90
02/14/89
09/30/87
09/08/88
08/29/90
c
c
c
c
c
c
e
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
Emiaaona,
NOx
Unoontr.
841
67
598
793
684
655
660
647
612
714
0
0
475
591
0
0
271
617
0
0
628
164
224
183
415
328
245
479
0
0
102
592
102
0
0
271
201
351
35
221
168
194
76
141
205
0
62
0
247
0
101
142
304
265
236
303
0
486
107
117
88
ppmv it to 1 5 paroant oxygen
Percent
Contr. reduction
12
7
30
18
45
38
41
17
37
46
8
25
31
26
37
24
37
39
20
18
17
3
6
3
2
12
1
1
17
65
1
3
11
27
18
15
31
17
20
13
7
31
35
13
5
41
20
45
28
14
12
30
14
5
35
16
10
19
23
12
7
99
90
95
98
93
94
94
97
94
94
0
0
94
96
0
0
86
94
0
0
97
98
96
98
100
97
100
100
0
0
99
99
87
0
0
94
85
95
43
94
96
84
54
91
98
0
68
0
89
0
88
79
96
98
85
95
0
96
79
90
92
CO
0
10669
3544
712
408
1357
948
1224
862
537
585
1375
4398
2238
232
1063
8662
968
3036
836
2273
5111
5504
2199
2879
2677
1074
6976
1954
1892
5187
8998
5542
809
1797
3946
4435
2740
14333
1629
12305
3535
14102
9970
3450
4095
1994
831
8641
480
8518
11969
4401
5829
7924
2436
1343
2825
2397
7706
2263
NMHC
0
87
30
22
105
167
0
122
0
137
13
0
64
48
0
17
0
31
89
0
0
0
0
3
0
14
0
0
0
50
0
0
0
142
9
26
0
7
0
0
0
0
0
0
0
0
3
226
0
0
0
0
0
7
0
0
6
0
0
0
28
A-6
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
305
305
305
305
305
305
305
305
305
305
320
320
320
320
320
320
320
320
320
320
320
320
320
321
321
321
321
321
321
321
321
321
322
322
322
322
322
322
322
322
322
330
330
330
330
330
331
331
331
331
332
332
332
332
333
333
333
333
333
334
334
Manufacturer
Waukasha
Waukesha
Waukesha
Waukesha
Waukesha
WaukMha
Waukesha
Waukesha
WaukMha
Waukesha
WaukMha
Wauk«aha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
WaukMha
Waukesha
WaukMha
WaukMha
WaukMha
Enterprise
Enterprise
enterprise
Enterprise
Entorpriee
Entarpriaa
cntarpnaa
EnterpriM
cnterpnes
Enterpnee
Enterpnee
cnterpnee
Enterprise
Enterprise
Enterprise
Enterprise
EntarpnM
Enterprise
Caterpillar
CatarpiNar
Model
F1197Q
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1187G
F1197Q
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
F1197G
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSG-6
GSM-B
GSM-8
GSM-8
GSM-8
GSM-8
G396
6398
Power
(hp)
150
150
150
150
150
150
150
150
150
150
150
150
150
98
150
150
150
150
150
150
150
150
150
150
150
150
150
150
98
150
150
150
150
150
150
150
98
150
150
150
150
465
465
465
465
465
520
520
520
520
520
520
520
520
300
300
300
300
300
420
420
Test Status
date
03/18/86
12/13/91
05/21/90
02/19/87
02/17/89
06/05/92
06/19/89
09/08/89
01/19/88
10/28/86
02/20/90
09/07/89
11/10/87
02/17/88
12/13/91
08/22/88
06/04/92
06/08/89
01/31/89
11/16/89
12/10/91
10/03/90
05/15/90
09/07/89
02/20/90
01/31/89
08/22/88
11/16/89
02/17/88
10/11/90
05/14/90
06/08/89
06/08/89
11/16/89
10/11/90
08/22/88
02/17/88
02/20/90
05/15/90
02/14/89
09/07/89
10/26/89
03/13/92
11/21/90
06/15/88
04/15/87
11/20/90
10/25/89
01/14/87
12/27/88
03/28/89
10/25/89
12/30/86
11/27/90
10/27/89
04/22/87
12/11/90
06/16/88
05/01/92
06/10/92
12/27/89
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
Emissions,
NOx
Unoontr.
119
36
106
64
120
0
79
75
87
572
154
95
747
146
190
90
0
104
102
177
0
489
225
39
117
98
33
40
211
565
62
31
355
90
481
231
488
68
190
436
90
93
0
361
39
29
457
625
561
728
317
325
237
611
428
131
367
33
0
0
606
ppmv at to 15 percent oxygen
Percent
Contr.
32
9
5
34
16
35
19
12
35
29
29
3
39
44
47
33
4
23
7
25
2
11
15
11
36
3
18
18
34
35
38
9
6
33
18
14
8
48
8
27
17
1
17
5
1
2
22
29
3
11
16
22
2
19
35
2
1
7
36
2
29
reduction
73
76
95
47
87
0
77
85
60
95
81
97
95
70
75
63
0
79
93
86
0
98
93
71
70
97
45
55
84
94
38
68
98
64
96
94
98
30
96
94
81
99
0
99
97
93
95
95
100
98
95
93
99
97
92
99
100
79
0
0
95
CO
12827
2696
4505
9250
9130
309
2801
10014
6721
2259
10369
12230
1105
10849
3911
13722
332
11684
9699
11779
453
393
4288
12874
5499
7077
12391
18210
7103
2002
10033
12008
2874
15666
770
8927
1578
10722
3785
2553
11463
19411
2213
Oft/?ft
OOvC
12840
11133
2232
1043
1804
1423
4386
4822
9474
1662
11700
11070
3155
14265
1398
1174
2745
NMHC
0
3
0
0
6
133
0
0
39
7
0
34
11
0
38
45
194
0
0
0
4
3
0
41
0
0
78
0
0
8
0
0
0
0
14
39
0
0
0
0
92
20
0
7
0
43
19
9
9
13
32
30
23
1
57
29
51
0
41
0
0
A-7
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
334
334
334
335
335
335
335
335
335
336
336
336
336
339
339
345
345
353
359
367
368
368
378
378
379
379
379
382
382
382
383
383
383
256
256
256
256
256
256
256
258
258
258
258
&w
271
271
271
271
271
271
278
278
278
278
278
278
278
yjtt
eif 0
278
290
290
Emieeton», ppmv at to 15 percent oxygen
Manufacturer
Caterpillar
Caterpillar
Caterpillar
CaterpWar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Waukeeha
Minneapolw-Mol
Minneapota-Mol
Tecogen
Teoogen
Tecogen Cogen
Tecogen
Tecogen Cogen
Teoogen
Teoogen Cogen
Waukeeha
Waukeeha
Weukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Ingereoll-Rand
Ingereoll-Rand
Ingereoll-Rand
Ingereoll-Rand
(ngeraoft-Rand
IngereoH-Rand
Ingereol-Rand
Ingereoll-Rand
Ingereoll-Rand
Ingereoll-Rand
Ingereol-Rand
Ingereol Rend
Ingereol-Rend
kinaianM r^nri
Ingereo*-Rend
Ingereol-Rend
Ingereol-Rend
Ingereoll-Rand
Ingereol-Rand
Ingereoll-Rand
Ingereoll-Rand
Ingereoll-Rand
• y |^_ rirl
efiyOrvOM 1 leVlO
Irbnave^tU flanrl
Ingereoll-Rand
Ingereolr-Rand
Ingereoll-Rand
Model
Q398
G398
G398
G398
G398
0398
Q398
G398
G398
G398
O398
G396
G398
3398
F2895
800-6A
800-6A
CM-75
CM-60
CM-75
CM-60
CM-60
CM-60
CM-60
H2476G
F1197G
F1197G
L5790G
L5790G
L5790G
L5790G
L5790G
L5790G
XVG-8
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
ytjA
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG
XVG-8
XVG
XVG
YVfi
AVO
XVG-S
XVG
SVG-10
Power
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
290
290
290
9QO
290
290
290
290
9
1677
4593
4723
2874
2279
9461
14342
4725
NMHC
37
2
0
0
33
0
0
0
20
12
0
10
0
0
244
47
0
0
0
0
11
0
9
6
0
7
0
6
7
0
0
0
7
0
0
1
5
0
8
0
0
0
0
5
6
0
0
0
0
16
11
0
374
7
0
9
A-9
-------
TABLE A-2. VENTURA COUNTY APCO EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
272
272
aw a»
272
272
272
272
318
318
318
318
318
318
319
319
319
319
319
319
319
319
358
358
61
61
82
82
82
82
82
82
82
82
82
82
82
82
82
82
86
86
86
86
86
86
86
86
86
86
86
86
89
«9
89
89
89
89
89
89
89
89
Manufacturer
Model Power
(hp)
IngaraoK-
Ingeraot-
Ingereolt-
Ingaraol
Awl
_.
Rand
•Rand
Rand
Rand
Waukaaha
Waukeeha
Waukaaha
Waukaaha
Waukaana
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Teoogan
Teoogen
(ngereoM-
fland
(ngaraoV-Rand
Waukaaha
Waukaaha
Waukeeha
Waukaaha
Waukeeha
Waukaaha
Waukeeha
Waukeeha
Waukaaha
Waukaaha
Waukeaha
Waukeeha
Waukeeha
Waukeaha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukaaha
Waukaaha
Waukaaha
Waukaaha
Waukaana
Waukaaha
Waukaana
Waukaaha
Waukaeha
Waukeaha
Waukaeha
Waukaeha
Waukaaha
Waukeeha
Waukeeha
Waukaaha
Waukeeha
Waukeeha
y\/Q
AW
XVG-fl
A »^*"O
XVG-8
XVG-8
XVG
XVG
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145GKU
145QKU
CM-75
CM-75
XVG
XVG
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
*W1
•Sftft
300
300
300
300
65
90
90
90
90
90
90
.90
90
90
65
90
90
90
108
108
350
350
775
775
775
775
775
858
775
775
775
775
775
858
775
858
775
775
775
775
775
858
775
775
775
775
858
775
775
858
775
858
775
775
775
775
858
775
ErrMorw,
Teat Statue NOx
date
nfi/imm
na/ru/fl7
09/25/88
03/19/86
06/17/86
03/18/88
02/16/88
11/12/87
06/15/89
10/03/90
05/14/90
09/07/89
08/15/89
09/15/89
06/23/88
02/22/90
02/18/88
11/12/87
12/01/89
Uooootr.
11 fad
IUV
419
•tiat
77
84
105
90
389
312
517
143
174
99
404
465
421
561
457
386
430
02/17/89 d 515
06/24/89 d 670
03/30/89 d 572
08/25/88 m 61
01/07/88 m 195
03/30/89 m 513
03/05/90 m 452
09/13/89 m 669
03/22/88 m 2014
12/06/87 m 571
05/27/87 m 597
12/12/89 m 690
06/29/88 m 2248
09/22/87 m 641
03/09/90 m 171
04/09/90 m 532
06/29/88 m 2248
06/30/89 m 629
03/10/87 m 596
12/08/87 r
n 660
03/05/90 m 497
06/05/89 m 213
09/14/89 m 865
03/22/88 m 2206
06/29/88 i
04/09/90 1
n 1922
n 505
09/22/87 m 668
06/29/88 m 1922
03/31/89 m 464
02/10/87 i
n 950
12/28/89 m 472
03/22/88 m 720
06/29/86 m 913
09/13/89 m 179
03/10/87 m 475
12/08/87 m 353
09/22/87 m 357
03/30/89 m 202
06/29/88 m 913
05/27/87 m 338
12/12/89 m 191
ppmv at to 15 percent oxygen
Corttr. reduction
1
17
27
39
1
2
5
3
8
5
28
26
9
42
19
6
16
31
115
99
48
2
12
37
14
227
29
55
18
53
18
5
44
53
31
18
10
27
12
14
59
42
32
21
42
32
3
15
7
1
2
0
0
3
1
1
3
2
99
73
74
57
100
99
99
98
95
95
93
95
98
93
96
96
96
94
83
83
41
99
97
91
98
89
95
91
97
98
97
97
92
98
95
97
99
95
94
94
97
98
94
97
96
93
100
97
99
100
99
1
1
99
99
100
99
99
CO
QttVt
Mflfi
9502
22439
10643
10868
1487
2587
1554
1510
3241
8647
4384
2943
560
1603
389
150
4316
2067
6652
'3120
6286
6490
2406
3812
477
2523
3098
1503
794
787
1621
12607
2641
787
1553
2541
1730
3163
8084
7687
1169
3796
3084
193
3798
3418
2848
1862
9020
8789
7928
4262
6040
5997
9701
8789
3900
9885
NMHC
0
18
0
0
0
18
0
0
0
42
0
0
0
8
0
2
0
14
36
8
314
33
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
49
0
0
0
0
0
0
0
0
0
0
0
A-10
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
89
91
91
91
91
91
91
91
91
91
91
91
91
92
92
92
92
92
92
92
92
92
92
92
92
92
316
316
316
316
11 fi
O 1 w
316
316
316
316
316
316
316
316
316
317
317
317
317
317
317
317
317
317
327
327
0
0
0
Manufacturer
Waukaaha
Waukeeha
Waukeeha
Waukaaha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukaaha
Waukeeha
Waukaaha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeeha
Waukeaha
Ingereoll-Rand
IngereoU-Rand
IngaraoH-Rand
IngereoU-Rand
InoeraoU-Rand
IngereolRand
IngeraoH-Rand
IngereoH-Rand
IngereoU-Rand
IngereoH-Rand
Ingereoll-Rand
Ingereoll-Rand
IngereoH-Rand
IngereoU-Rend
IngereoH-Rand
IngereoH-Rand
IngereoH-Rand
IngereoH-Rand
IngereoH-Rand
IngareoH-Rand
IngereoH-Rand
IngereoH-Rand
IngereoH-Rand
IngereoH-Rand
InaeraoH-Rand
Model
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
L7042G
SVG-6
SVG-6
SVG-6
SVG-6
ov/rs-fi
O W^9
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVO-6
SVG-6
SVG-6
QWrtJS
ovvj-o
SVG-6
SVG-6
SVG-6
SVG-6
SVG-6
SVG-8
SVG-8
SVG-10
SVG-12
SVG-12
Power
(hp)
775
775
775
775
775
775
858
775
775
775
775
858
858
775
775
775
775
658
858
775
775
858
775
775
775
775
330
330
330
330
oon
<>i7U
330
330
330
330
330
330
330
330
330
330
330
330
330
•W)
o*^/
330
aao
330
330
330
330
330
440
440
550
660
660
Test Status
date
06/05/89
03/05/90
12/12/89
03/30/89
09/13/89
09/22/87
06/29/88
03/22/88
12/08/87
06/29/88
06/05/89
03/10/87
05/28/87
03/31/89
12/08/87
09/22/87
12/12/89
05/29/87
06/29/88
09/14/89
06/30/89
02/06/87
06/29/88
03/09/90
03/09/90
03/22/88
05/15/90
03/20/86
06/10/87
06/09/86
no/ny/po
V9IVI /O9
1 9/1 fl/Afi
1 £/ 1 \Jl Ow
10/19/90
08/23/88
12/15/87
02/26/87
02/22/90
02/14/89
08/27/86
09/29/87
02/18/88
11/30/89
08/23/88
(V3/1 Q/A7
U^r 1 9/Or
02/17/89
04/07/86
1 9/1 7/flfi
1 4W 1 ' /OO
no/oo/tus
UO/cO/OO
09/29/87
10/03/90
02/18/88
06/15/89
12/15/87
02/06/89
09/18/89
08/28/86
11/24/86
12/01/86
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
m
in
m
m
m
rn
m
m
m
m
m
m
m
Emissions,
NOx
Uncontr.
157
674
154
144
163
335
879
1342
283
879
135
180
512
489
539
494
409
773
2562
385
493
1614
2562
477
559
2589
245
266
201
236
9A9
£t£
319
326
562
227
417
332
176
412
318
322
207
433
263
372
9«51
177
307
358
142
373
519
240
42
519
461
ppmv at to 15 percent oxygen
Percent
Corrtr.
1
33
4
3
4
6
4
24
1
4
1
0
8
1
1
2
13
1
16
3
6
2
16
1
1
3
10
20
5
10
6
20
10
5
11
7
8
13
16
15
2
3
7
/
19
4
1
3
11
4
10
21
30
1
1
4
4
reduction
99
94
98
97
98
98
100
98
100
100
99
1
98
99
100
100
97
100
99
99
99
100
99
99
99
100
96
93
98
96
Qfl
9O
98
94
98
98
97
98
96
97
95
98
99
inn
i \AJ
99
QO
9O
95
ino
IUU
98
97
99
93
94
94
100
98
99
99
CO
10676
867
6651
10138
8651
5997
9019
4780
6608
9019
11318
9631
1900
5326
4102
10825
7867
60
1231
5733
7233
4534
1231
85
8336
5829
3400
5672
3460
4768
A91 1
Oe£ 1 1
4Q71
*9f I
2268
7677
790
4978
484
3305
7275
2524
4083
4596
5421
9fisn
2408
368
K7KA
379B
2678
2579
2554
7133
295
865
4602
14722
2580
3805
NMHC
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
18
0
0
0
0
7
8
0
0
8
0
6
0
0
0
0
0
0
0
0
4
1
0
0
7
0
0
10
16
0
6
5
A-ll
-------
TABLE A-2. VENTURA COUNTY APCD EMISSION DATABASE FOR NSCR CONTROL FOR 1C ENGINES.
Engine
No.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
76
76
931
Manufacturer
Model Power
(hp)
Minneapofe-Mol
Ingereow-Rand
(ngeraoft-Rand
White Superior
Waukeeha
Waukeeha
btMAmnll Danrl
Whrte Superior
!•. „•••..< » — i
HigervOH-nana
Inger»oft-Rand
White Superior
Waukeeha
Wauketha
Inger»o>-Rand
lngen»oH-Rand
(ngereott-Rand
Ingereoll-Rand
IngeraoB-Rand
Waukeaha
Waukeaha
800-6A
SVG-10
XVQ
o-azss
F11970
F1197Q
SVO-12
G-8258
SVO-12
SVG-12
G-62S6
SVQ-12
F11970
F11970
SVO-12
SVG-10
SVG-10
SVG-12
XVG
GMVA-8
GMVA-8
cwrjjj
80
550
300
625
150
150
660
625
660
660
625
660
150
150
660
500
550
660
300
165
165
AAfl
EmiatkxM,
Test Statua NOx
date
07/13/92
06/16/86
12/07/88
12/17/82
11/10/87
11/10/87
02/09/82
12/17/82
11/24/86
12/12/86
12/17/82
10/20/87
06/11/87
06/11/87
10/22/87
04/02/82
12/09/86
02/09/82
12/31/85
06/15/87
07/02/86
19/1 A/07
Unconfr.
0
260
57
0
449
479
537
572
758
315
2
747
63
39
565
432
180
449
311
174
384
•««
ppmv at to 15 percent oxygen
r* *
^•rosfn
Contr. reduction
6
17
22
0
17
3
6
5
3
8
2
23
27
20
4
61
1
3
3
19
23
i
0
94
61
0
96
99
99
99
100
96
0
97
57
49
99
86
99
99
99
89
94
1IY1
CO
164
5387
13606
60
3217
3575
1021
1695
2834
5933
3191
0
5220
7665
0
2638
4652
1146
8056
8894
2752
7OK
NMHC
4
0
30
47
5
3
31
73
6
6
76
0
0
0
0
0
0
101
5
117
0
«
A-12
-------
TABLE A-3. VENTURA COUNTY APCD EMISSION DATABASE FOR LOW-EMISSION ENGINES DEVELOPED FROM RICH-BURN DESIGNS
Engine
No.
74
74
74
74
74
74
74
74
74
74
75
75
75
75
75
75
75
75
75
75
295
295
295
295
295
295
295
295
295
295
296
296
296
296
296
296
296
296
296
296
296
296
296
297
297
297
297
297
297
297
297
297
297
297
297
297
297
297
298
298
298
298
298
Test
No.
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
11
12
13
14
1
2
2
2
3
4
5
6
7
8
9
10
11
12
13
1
2
3
4
5
Manufacturer
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Superior
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Model
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
16SGTA
L7042GL
L7042GL
L7042GL
L7042GL
L7042GU
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
Power
-------
TABLE A-3. VENTURA COUNTY APCO EMISSION DATABASE FOR LOW-EMISSION ENGINES DEVELOPED FROM RICH-BURN DESIGNS
Emissions, ppmv at 15 percent oxygen
Engine
No.
296
296
296
296
296
296
296
296
296
299
299
299
299
299
299
299
299
299
299
299
300
300
300
300
300
300
300
300
300
300
300
301
301
301
301
301
301
301
301
301
301
301
302
302
302
302
302
302
302
302
302
302
354
354
355
355
356
356
362
363
Test
No.
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
1
2
3
4
5
6
7
8
9
10
11
1
2
3
4
5
6
7
8
9
10
11
1
2
3
4
5
6
7
8
9
10
1
2
1
2
1
2
1
1
Manufacturer
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukesha
Waukeaha
Waukesha
Waukesha
Superior
Superior
Superior
Superior
Superior
Superior
Waukesha
Waukesha
Model
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GL
L7042GU
8GTLB
8GTLB
8GTLB
8GTLB
8GTLB
8GTLB
F3521GL
F3521GL
POWWT
-------
TABLE A-4. VENTURA COUNTY APCO EMISSION DATABASE FOR LOW-EMISSION 1C ENGINES DEVELOPED FROM LEAN-BURN DESIGNS
Emissions, ppmv at 15 percent oxygen
Engine
No.
ftf
Of
K7
OV
K7
Of
67
67
fif
Of
67
67
AA
DO
116
116
116
116
116
116
116
117
117
117
117
117
117
117
117
117
117
117
117
117
117
117
117
118
118
118
118
118
118
118
118
118
118
118
118
118
118
118
118
119
119
119
119
119
119
119
119
119
119
119
119
119
119
119
119
Teet
No.
4
5
7
8
4
1
1
2
3
4
5
6
7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Manufacture
f*f*f^* DM i
Cooper Beeeemer
Cooper BeMemer
Cooper Bessemer
Cooper Bwwofiwf
Aj*x
AIM
Ajax
Ajax
Aj«x
Ajax
Ain
Ajax
Ajax
Aiax
Ajax
Aiax
Aiax
Ajax
Ajax
Aiax
AMU
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
A|ax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Ajax
Aiax
Aj«x
Ajax
Model
GMVA-6
GMVA-8
QMVA-8
GMVA-6
GMVA-8
GMVA-6
GMVA-6
/3UWA_ft
UMVA-O
GMVA-8
DCP-180
DCP-180
OCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-160
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
OCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-160
DCP-180
DCP-180
OCP-160
DCP-180
DCP-160
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-180
DCP-1BO
DCP-180
DCP-180
DCP-180
Power
(hp)
1100
1100
1100
1110
1100
1100
1100
1 1IVI
1 IIW
1100
180
ISO
160
ISO
180
160
180
180
160
180
180
180
180
180
160
180
160
180
180
180
180
180
180
180
180
180
160
180
180
180
180
180
180
180
160
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
Test
date
02/06/86
05/05/86
08/22/86
10/31/86
02/06/87
05/08/87
01/08/88
lA/VWAO
iwourow
01/13/89
06/07/87
05/17/89
08/19/88
12/12/88
03/20/90
08/14/90
09/23/91
07/03/86
10/02/86
02/09/87
04/23/87
08/06/87
04/18/88
06/10/88
09/13/88
12/01/88
02/21/89
05/17/89
09/19/89
12/12/89
03/20/90
06/14/90
09/23/91
07/02/86
10/02/86
01/09/87
04/22/87
08/06/87
04/18/88
06/10/88
00/13/88
12/01/88
02/21/89
05/17/89
09/19/89
12/12/89
03/20/90
06/14/90
09/23/91
07/02/86
10/02/86
01/08/87
04/22/87
08/07/87
04/18/88
06/10/88
09/13/88
12/01/88
02/21/89
05/17/89
09/19/89
12/12/89
03/20/90
06/14/90
09/23/91
Status
g
Q
C
c
c
Q
c
c
g
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
NOx
64
65
218
71
236
97
248
inuc
1UM
302
51
60
38
38
42
33
40
78
51
35
56
55
50
44
25
84
57
60
38
71
37
38
25
49
28
39
28
53
78
60
18
44
61
55
32
38
41
45
45
30
18
46
30
60
35
28
21
45
28
38
45
38
27
61
30
CO
40
68
0
0
0
o
0
53
1284
0
0
0
0
528
235
0
0
0
0
739
0
0
0
74
0
0
0
0
0
682
225
0
0
0
0
759
0
0
0
138
0
0
0
0
0
976
510
0
0
0
0
719
0
0
0
25
0
0
0
0
0
1380
556
NMHC
178
173
165
189
109
0
0
72
82
0
89
98
0
86
95
127
108
132
112
98
128
0
110
155
0
0
87
113
0
118
93
227
195
113
155
114
159
0
133
165
0
0
143
126
0
148
133
91
86
102
102
103
141
0
80
174
0
0
104
128
0
143
179
A-15
-------
TABLE A-5. VENTURA COUNTY APCD EMISSION DATABASE FOR SCR USED WITH LEAN-BURN RECIPROCATING ENGINES
Engine
No.
45
45
45
45
45
47
47
47
47
47
139
1 W9
139
1 vv
9elA
fc*»O
248
24A
fc"iO
9AR
fc^W
94ft
2
-
OAK
f^v
309
309
309
309
309
309
309
309
309
309
309
309
357
357
Teet
No.
1
2
3
4
5
1
2
3
4
5
4
1
2
m
1 W
1
2
3
4
5
6
7
8
9
10
11
12
1
2
Manufacturer
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
dark
Clark
Clerk
dark
Clerk
Clerk
Tecogen
Tecogen
Model Power Teet Statue
HRA-6
HRA-6
HRA-6
HRA-6
HRA-6
HRA-6
HRA-6
HRA-6
HRA-6
HRA-6
GMV
UIVI V
GMV
\jfn »
OMV-8
/^t*\/ Q
WMV-o
ruv.fi
f*lLJW_fi
UMV-o
ftMV-fi
ftUV.fi
UIV1 »"Q
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
HRA-32
CM-200
CM-200
(hp)
660
660
660
660
660
660
660
660
660
660
Mfl
wwv
660
IMA/
800
A/V1
00U
Ann
Ann
Ann
ouu
Ann
ow
Ann
OVA/
350
350
350
350
350
350
350
350
350
350
350
350
291
291
date
12/22/86
05/06/88
05/02/89
04/23/90
08/12/92
03/26/87
06/26/88
05/23/89
04/23/90
06/12/92
08/04/88
»M*f«^'rOO
na/ia/B7
«A7|f 1 wyOr
08/03/87
n£/1 A/B7
U6/1U/B7
m/HA/AA
W 1 f\JO/OO
M»MAMp
UO/Z9/BB
AAjno/AA
MP/wV/OQ
OS/ft?/*1)
ns/^«o
04/28/86
06/27/86
12/17/86
02/26/87
06/11/87
10/08/87
12/15/87
03/30/88
09/09/88
03/15/89
06/16/89
10/30/89
12/07/89
04/13/90
EriMeiona, ppmv at 15 percent oxygen
Percent
NOx In NOx out reduction
c
c
c
c
c
c
c
e
c
c
m
m
fn
fn
fn
fn
m
m
m
m
m
m
m
m
m
m
m
m
c
c
1094
885
636
1312
562
672
1159
619
1237
679
170
1 i W
1100
filfl
01 o
779
* r V
T*A
K7A
0f V
972
91 C
220
259
238
211
293
556
373
303
314
199
161
336
354
646
180
104
55
166
64
82
155
72
222
83
1K1
I w i
170
1 i W
77
/ 1
83
1AA
100
132
Ivtt
96
^w
AR
••w
67
90
39
50
52
111
111
63
75
61
55
100
10
36
84
88
91
87
89
88
87
88
82
88
A7
Or
93
fl7
OY
90
70
65
84
76
82
80
70
79
76
69
67
70
97
95
CO out NMHCout
217
243
364
181
152
246
231
225
191
416
91 S
at 10
177
559
42O
«ao
i2a
BB4
•^^^
ADS
485
460
310
289
206
214
396
273
359
362
167
325
7574
406
305
132
197
0
272
197
160
95
0
401
19A3
laCWw
256
1817
1 O 1 *
4K9
ooc
0
0
204
0
0
0
473
0
0
0
0
0
14
4
A-16
-------
REFERENCE FOR APPENDIX A
1. Diskette from Price, D. R., Ventura County Air Pollution
Control District, to Snyder, R. B., Midwest Research
Institute. Received March 22, 1993. Data base of
reciprocating engine emission test summaries (ENGTESTM.DBF)
A-17
-------
APPENDIX B.
This appendix contains tables of the cost and cost-
effectiveness figures presented in Chapter 6. The methodologies
used to calculate the values shown in these tables are discussed
in Chapter 6.
B-l
-------
TABLE B-l. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF AN
AUTOMATIC A/F CONTROL SYSTEM TO A RICH-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Power
Output,
hp
80
150
250
350
500
650
850
1.200
1.600
ZOOO
2.500
4,000
6,000
8.000
Heat
Rate.
Btu/hp-hr
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Heat
Rate.
Btu/hp-hr
8.140
8,140
7,820
7.820
7.540
7.540
7,540
7.460
7,460
7.460
6,780
6,780
6.680
6,680
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Hours
Per
Year
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
Capital
Equipment
CostJ
Sales Tax
& Freight
S
7.000 560
7.000 560
7.000 560
7.000 560
7.000 560
7.000 560
7.000 560
10,000 800
10,000 800
10.000 800
10.000 800
15.000 1.200
15.000 1.200
15,000 1.200
ANNUAL COSTS
Maintenance.
S
700
700
700
700
700
700
700
1.000
1.000
1.000
1.000
1.500
1.500
1,500
Overhead,
S
420
420
420
420
420
420
420
600
600
600
600
900
900
900
Direct and
Indirect Total
Installation, Capital
Contingency. S Cost S
3.850
3.850
3,850
3,850
3.850
3.850
3.850
5.500
5,500
5.500
5.500
8.250
8.250
8.250
Fuel
Penalty,
S
1,080
2,020
3,230
4.520
6.220
8,090
10.600
14.800
19.700
24,600
28.000
44.800
66.200
88,200
11.400
11.400
11.400
11.400
11.400
11.400
11.400
16,300
16.300
16.300
16.300
24.500
24.500
24.500
Taxes,
Insurance,
Admin..
S
456
456
456
456
456
456
456
652
652
652
652
978
978
978
Compliance
Test
S
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2,440
2,440
Capital
Recovery.
S
1.250
1.250
1.250
1.250
1.250
1.250
1.250
1.790
1.790
1,790
1.790
2.680
2.680
2.680
•
Total
Annual
Cost
S
6.340
7.290
8.500
9.790
11.500
13.400
15.900
21,300
26.200
31.100
34.500
53.300
74.700
96.700
COST EFFECTIVENESS
Power
Output.
hp
80
150
250
350
500
650
850
1,200
1.600
1000
2.500
4.000
6.000
8.000
Heat
Rate,
Btu/hp-hr
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7,460
7,460
7,460
6.780
6.780
6.680
6.680
Hour* Uncontrolled
Per NOx,
Year tons/yr
8,000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
8,000
11.1
209
34.8
48.7
69.6
90.5
118
167
223
278
348
557
835
1.110
NOx
reduction,
%
20
20
20
20
20
20
20
20
20
20
20
20
20
20
Controlled
NOx.
tons/yr
8.91
16.7
27.8
39.0
55.7
72.4
94.6
134
178
223
278
445
668
891
NOx
removed,
tons/yr
2.23
4.17
6.96
974
13.9
18.1
23.7
33.4
44.5
55.7
69.6
111
167
223
Total
annual
costS
6.340
7.290
8300
9.790
11.500
13.400
15.900
21.300
26.200
31.100
34.500
53.300
74.700
96,700
Cost
effectiveness,
S/ton NOx
removed
2.850
1,740
1,220
1.000
826
739
670
637
588
559
495
479
447
434
B-2
-------
TABLE B-2. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF AN
ELECTRONIC IGNITION SYSTEM TO A RICH-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2,000
2.500
4.000
6.000
8.000
Power
Output
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4,000
6.000
8,000
Heat
Rate.
Btu/hp-hr
8.140
8.140
7.820
7,820
7.540
7,540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Heat
Rale.
Btu/hp-hr
8.140
8.140
7.820
7,820
7.540
7.540
7.540
7.460
7,460
7.460
6.780
6,780
6.680
6,680
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Hours
Per
Year
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8,000
8.000
8,000
8,000
Capital
Equipment
Cost.$
Sales Tan
& Freight
S
7,500 600
7.500 600
7.500 600
7.500 600
7.500 600
7.500 600
7.500 600
10.000 800
10.000 800
10.000 800
10.000 800
15,000 1.200
15.000 1.200
15.000 1.200
ANNUAL COSTS
Maintenance.
$
750
750
750
750
750
750
750
1.000
1,000
1,000
1,000
1,500
1.500
1,500
Overhead
S
450
450
450
450
450
450
450
600
600
600
600
900
900
900
Direct and
Indirect
Installation.
Contingency. S
4.130
4.130
4.130
4.130
4.130
4.130
4,130
5,500
5,500
5,500
5.500
8.250
8.250
8.250
Fuel
Penalty,
$
869
1.630
2.610
3.650
5.030
6.540
8.560
12.000
15.900
19.900
22.600
36.200
53,500
71.300
Total
Capital
CostS
12.200
12.200
12.200
12.200
12.200
12.200
12.200
16.300
16.300
16,300
16,300
24.500
24,500
24.500
Taxes.
Insurance,
Admin.,
S
489 '
489
489
489
489
489
489
652
652
652
652
978
978
978
Compliance
Test
S
2.440
2.440
2.440
2.440
2,440
2.440
2.440
2,440
2.440
2,440
2.440
2.440
2,440
2,440
Capital
Recovery,
S
1.340
1.340
1,340
1,340
1,340
1,340
1.340
1,790
1,790
1.790
1,790
2,680
2.680
2.680
Total
Annual
Cost,
S
6.340
7.100
8,080
9,130
10.500
12.000
14,000
18.400
22.400
26,400
29.100
44,700
62.000
79.800
COST EFFECTIVENESS
Power
Output
hp
80
150
250
350
500
650
850
1,200
1,600
1000
2,500
4,000
6,000
8.000
Heat
Rate.
Btu/hp-hr
8.140
8.140
7.820
7.820
7,540
7.540
7.540
7.460
7,460
7.460
6,780
6.780
6,680
6.680
Hours
Per
Yew
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8,000
8.000
Uncontrolled
NOx,
tonstyr
11.1
20.9
34.8
48.7
69.6
90.5
118
167
223
278
348
557
835
1110
NO*
reduction.
%
20
20
20
20
20
20
20
20
20
20
20
20
20
20
Controlled
NOx.
tons/yr
8.91
16.7
27.8
39.0
55.7
72.4
946
134
178
223
278
445
668
891
NOx
removed.
tons/yr
2.23
4.17
6.96
9.74
13.9
18.1
23.7
33.4
44.5
55.7
69.6
111
167
223
Total
annual
cost S
6.340
7,100
8.080
9,130
10,500
1ZOOO
14.000
18.400
2Z400
26,400
29,100
44,700
6ZOOO
79.800
Cost
effectiveness.
S/tonNOx
removed
2.850
1.700
1.160
937
755
664
593
552
503
474
418
402
371
359
B-3
-------
TABLE B-3. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF
AUTOMATIC A/F CONTROL AND ELECTRONIC IGNITION SYSTEMS TO A
RICH-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8,000
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
ZOOO
2.500
4.000
6.000
8.000
Heat
Rate.
Bru/hp-rtr
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6,780
6,680
6.680
Heat
Rate.
Bru/hp-hr
8.140
8,140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Hours
Per
Year
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
8.000
8,000
8.000
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Capital
Equipment
COSL$
Sales Tax
& Freight.
S
14,500 .160
14.500 .160
14.500 .160
14.500 ,160
14.500 .160
14.500 ,160
14.500 .160
20.000 .600
20.000 .600
20.000 .600
20.000 .600
30.000 2,400
30,000 2.400
30,000 2,400
ANNUAL COSTS
Maintenance.
$
1.450
1.450
1.450
1.450
1.450
1.450
1.450
2,000
ZOOO
2.000
ZOOO
3.000
3.000
3,000
Overhead.
5
870
870
870
870
870
870
870
1.200
1.200
1,200
1.200
1.800
1.800
1.800
Direct and
Indirect
Installation,
Contingency. $
7.980
7.980
7,980
7.980
7.980
7.980
7.980
11.000
11.000
11.000
11.000
16.500
16.500
16,500
Fuel
Penalty.
S
1.510
2.820
4320
6.330
8.710
11.300
14,800
20.700
27.600
34,500
39.200
6Z700
9Z600
124.000
Total
Capital
Cost.*
23.600
23.600
23.600
23.600
23.600
23.600
23.600
32.600
3Z600
32.600
3Z600
48.900
48.900
48.900
Taxes,
Insurance,
Admin..
S
945
945
945
945
945
945
945
1.300
1,300
1,300
1.300
1.960
1.960
1,960
Compliance
Test,
S
2.440
2.440
2,440
2.440
2.440
2,440
2.440
2.440
2.440
2.440
2.440
2.440
2,440
2,440
Capital
Recovery.
S
Z590
Z590
Z590
Z590
2,590
Z590
Z590
3.580
3.580
3.580
3,580
5,370
5,370
5,370
Total
Annual
Cost.
$
9.810
11.100
12.800
14,600
17,000
19.600
23,100
31.200
38.100
45.000
49.700
77.300
107,000
138.000
COST EFFECTIVENESS
Power
Output.
hp
80
150
250
350
500
650
850
1,200
1.600
' 1000
2,500
4.000
6,000
8.000
Heat
Rate,
Btu/hp-hr
8,140
8.140
7,820
7,820
7.540
7.540
7,540
7,460
7,460
7.460
6,780
6.780
6.680
6.680
Hours
Per
Ye«r
8,000
8,000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8,000
8,000
Uncontrolled
NOx,
toni/yi
U.I
20.9
34.8
48.7
69.6
90.5
118
167
223
278
348
557
835
1110
NO*
reduction.
%
30
30
30
30
30
30
30
30
30
30
30
30
30
30
Controlled
NOx,
tons/ VT
7.79
14.6
24.4
34.1
48.7
63.3
82.8
117
156
195
244
390
584
779
NOx
removed.
tons/yr
3.34
6.26
10.4
14.6
20.9
27.1
353
50.1
66.8
83.5
104
167
250
334
Total
annual
costS
9.810
11.100
12.800
14.600
17.000
19.600
23,100
31,200
38,100
45,000
49,700
77,300
107,000
138.000
Cost
effectiveness
SAon NOx
removed
Z940
1.780
1.230
1.000
815
723
651
623
571
539
476
463
428
413
B-4
-------
TABLE B-4. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF A
PRESTRATIFIED CHARGE (PSC®) SYSTEM, WITHOUT TURBOCHARGER
MODIFICATION OR ADDITION, TO A RICH-BURN SI ENGINE
CAPITAL COSTS
Power
Output
hp
80
150
250
350
500
650
850
1,200
1.600
2.000
2.500
4.000
6.000
8.000
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4,000
6,000
8.000
Heat
Rate.
Btu/hp-hi
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Heat
Rate,
Btu/hp-hr
8.140
8.140
7.820
7.820
7.540
7.540
7,540
7.460
7,460
7,460
6.780
6.780
6,680
6.680
Hours
Per
Year
Capital
Equipment
CostS
Sales Tan
& Freight.
$
8.000 11.800 948
8,000 18.800 1.500
8,000 24.900 2.000
8.000 28.400 2.280
8.000 31,000 2.480
8.000 32.100 2.570
8.000 33,300 2.670
8.000 34,600 2.770
8.000 35.700 2,860
8,000 36.800 2,940
8.000 38.200 3.050
8.000 42.300 3.380
8,000 47.800 3.820
8.000 53.300 4.260
ANNUAL COSTS
Hours
Per
Year
8.000
8,000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
Operating
Labor.
$
54.000
54,000
54,000
54,000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54,000
Supervisory
Labor.
$
8.100
8.100
8.100
8,100
8,100
8.100
8.100
8.100
8,100
8,100
8,100
8,100
8.100
8.100
Direct and
Indirect
Installation.
Contingency. $
6.520
10.300
13.700
15,600
17,000
17,700
18.300
19.000
19.600
20.200
21.000
23.300
26.300
29,300
Maintenance,
$
1.180
1.880
2.490
2,840
3,100
3.210
3.330
3.460
3.570
3.680
3.820
4,230
4,780
5,330
Total
Capital
CostS
19,300
30.600
40.700
46.400
50,500
52,400
54,300
56.400
58.200
60,000
62.200
68.900
77.900
86,800
Overhead.
S
711
1.130
1,500
1.710
1.860
1,930
2,000
2.080
2,140
2,210
2,290
2.540
2,870
3.200
Fuel
Penalty,
S
430
806
1.290
1,810
2.490
3.240
4.230
5,910
7.880
9.850
11.200
17.900
26,500
35,300
Taxes.
Insurance.
Admin..
$
772
1.220
1.630
1.850
2.020
2.100
2,170
2.260
2.330
2.400
2,490
2,760
3,110
3.470
Compliance
Test
S
2.440
2.440
2.440
2,440
2.440
2,440
2.440
2.440
2.440
2,440
2.440
2,440
2.440
2.440
Capital
Recovery,
S
2.120
3,360
4,460
5.090
5.550
5.750
5.970
6.190
6.390
6.580
6.830
7.570
8.550
9.530
Total
Annual
Cost
S
69.800
72,900
75,900
77.800
79.600
80.800
82.200
84.400
86.800
89.300
91.200
99.500
110.000
121.000
COST EFFECTIVENESS
Power
Output
hp
80
150
250
350
500
650
850
1.200
1,600
2,000
2.500
4,000
6.000
8.000
Heat
Rate.
Btu/hp-hi
8,140
8.140
7.820
7,820
7.540
7,540
7.540
7.460
7.460
7,460
6.780
6,780
6,680
6,680
Hours Uncontrolled
Per NOx,
Year tons/yi
8.000
8.000
8,000
8.000
8.000
8,000
8,000
8,000
8,000
8,000
8.000
8,000
8,000
8,000
11.1
20.9
34.8
48.7
69.6
90.5
118
167
223
278
348
557
835
1110
Controlled
NOx.
g/hp-hr
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Controlled
NOx.
tons/yr
1.41
2.64
4.41
6.17
8.81
11.5
15.0
21.1
28.2
35.2
44.1
70.5
106
141
NOx
removed
tons/yr
9.72
18.2
30.4
42.5
60.8
79.0
103
146
194
243
304
486
729
972
Cost
Total effectiveness.
annual $/ton NOx
cost $ removed
69.800
72.900
75,900
77,800
79,600
80.800
82.200
84.400
86.800
89,300
91,200
99.500
110,000
121,000
7.170
4.000
2,500
1,830
1.310
1,020
7%
579
447
367
300
205
151
125
B-5
-------
TABLE B-5. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF A
PRESTRATIFIED CHARGE (PSC®) SYSTEM, WITH TURBOCHARGER
MODIFICATION OR ADDITION, TO A RICH-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Power
Output
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2,500
4.000
6.000
8.000
Heat
Rate.
Btu/hp-hr
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Heat
Rate.
Bru/hp-hr
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6,780
6.680
6.680
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8,000
8.000
Hours
Per
Year
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8,000
8.000
8.000
Capital
Equipment
Cost.!
Sales Tax
& Freight
$
16.100 1,290
28.100 2.250
42.300 3.380
53.200 4,250
64,500 5.160
71.100 5.690
75.100 6,010
78.800 6.300
81300 6.520
84.100 6.730
87.400 6.990
97.300 7.780
110.000 8.830
124.000 9.880
ANNUAL COSTS
Operating
Labor.
$
54.000
54,000
54,000
54,000
54.000
54.000
54,000
54.000
54.000
54,000
54,000
54,000
54.000
54.000
Supervisory
Labor.
S
8.100
8.100
8,100
8,100
8.100
8,100
8,100
8.100
8.100
8.100
8.100
8.100
8.100
8.100
Direct and
Indirect
Installation,
Contingency. S
10.500
18.300
27300
34.600
41.900
46.200
48.800
51.200
53,000
54.700
56.800
63.200
71.700
80.300
Maintenance.
S
1.610
2.810
4.230
5.320
6,450
7.110
7,510
7.880
8.150
8.410
8.740
9.730
11.000
12.400
Total
Capital
CostS
27,900
48,700
73.100
92,000
112.000
123.000
130.000
136.000
141.000
146.000
151.000
168.000
191,000
214.000
Overhead.
S
967
1.690
2.540
3.190
3.870
4.270
4.510
4.730
4.890
5.050
5.240
5.840
6.620
7.410
Fuel
Penalty,
S
430
806
1.2W
1.810
2.490
3.240
4.230
5,910
7,880
9.850
11.200
17,900
26300
35.300
Taxes,
Insurance.
Admin..
$
1,120
1,950
2,920
3.680
4.460
4.920
5.200
5.450
5,640
5.820
6,050
6.730
7.640
8.550
Compliance
Test
S
2.440
2.440
2,440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2,440
2,440
2.440
2.440
Capital
Recovery,
S
3,060
5.350
8,030
10,100
12,300
13.500
14.300
15.000
15.500
16.000
16.600
18.500
21.000
23.500
Annual
Cost
S
71,700
77.100
83.500
88.600
94.100
97.600
100.000
103,000
107.000
110.000
112.000
123.000
137.000
152.000
COST EFFECTIVENESS
Power
Output,
hp
80
150
250
350
500
650
850
1.200
1,600
2.000
2.500
4.000
6.000
8.000
Heat
Rate.
Bru/hp-hr
8.140
8.140
7.820
7.820
7340
7340
7340
7,460
7.460
7.460
6.780
6,780
6.680
6.680
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
Uncontrolled
NOx,
tons/yr
11.1
20.9
34.8
48.7
69.6
903
118
167
223
278
348
557
835
1110
Controlled
NOx,
g/hp-hr
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Controlled
NOx,
tons/yr
1.41
2.64
4.41
6.17
8.81
11.5
15.0
21.1
28.2
35.2
44 1
70.5
106
141
NOx
removed
lons/vr
9.72
187
30.4
423
60.8
79.0
103
146
194
243
304
486
729
972
Total
annual
costS
71.700
77,100
83300
88.600
94.100
97.600
100,000
103.000
107.000
110.000
112,000
123.000
137,000
15ZOOO
Cost
effectiveness,
SAon NOx
removed
7.380
4.230
Z750
1080
1350
1.240
970
709
548
451
370
253
188
156
B-6
-------
TABLE B-6. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF
NONSELECTIVE CATALYTIC REDUCTION (NSCR) TO A RICH-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
80
150
250
'50
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8,000
Heu
Rate,
Blu/hp-hr
8.050
8.050
7.830
7.810
7.700
7.700
7.470
7.470
7.440
7.440
7.110
7.110
6.800
6.800
Heat
Rate.
Bru/hp-hr
8.050
8.050
7.830
7.830
7,700
7.700
7.470
7,470
7.440
7,440
7.110
7.110
6.800
6.800
Hours
Per
Year
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Hours
Per
Year
8.000
8.000
8.000
8,000
8.000
8,000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Capital
Equipment
Cost. $
Sales Tax
& Freight,
$
7.200 576
8.250 248
9.750 293
11.300 1?8
13.500 405
15,800 473
18.800 563
24.000 720
30.000 900
36.000 1.080
43.500 1.310
66.000 1 .980
96.000 2,880
126.000 3.780
ANNUAL COSTS
Operating
Labor.
J
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
54.000
Supervisory
Labor.
J
8.100
8.100
8.100
8.100
8,100
8.100
8.100
8.100
8.100
8,100
8.100
8.100
8.100
8.100
Direct and
Indirect Total
Installation. Capital
Contingency. $ Cost. $
7.060
8.090
9.560
11.000
13.200
15.400
18.400
23.500
29.400
35.300
42.600
64.700
94.100
123,000
Maintenance.
$
720
825
975
1.130
1,350
1.580
1.880
2.400
3,000
3.600
4.350
6.600
9.600
12.600
14,800
16.600
19.600
22.600
27.100
31.700
37.700
48,200
60.300
72.400
87.400
133.000
193.000
253.000
Overhead.
S
432
495
585
675
810
945
1.130
1,440
1.800
2.160
2.610
3.96%
5,760
7.560
Fuel
Penalty.
$
1.060
1,990
3.230
4.530
6.360
8.270
10.500
14.800
19.700
24.600
29.300
46.900
67.400
89.800
Catalyst
Cleaning,
S
22.0
41.3
688
96.3
138
179
234
330
440
550
688
1.100
1.650
2200
Catalyst
Replacement,
$
293
550
917
1.280
1.830
2.380
3.120
4.400
5,870
7,330
9,170
14,700
22,000
29.300
Taxes.
Insurance.
Admin..
J
593
663
784
905
1,090
1.270
1,510
1,930
2.410
2,890
3.500
5,310
7.720
10.100
Compliance
Test,
J
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2,440
2.440
2.440
2,440
2.440
2.440
2,440
Capital
Recovery.
S
1.630
1.820
2.150
2.480
2.980
3.480
4.140
5.300
6.620
7.940
9.600
14.600
21.200
27.800
Total
Annual
Cost.
%
69.300
70,900
73.300
75.600
79.100
82.600
87.000
95.100
104,000
114.000
124.000
158.000
200.000
244.000
COST EFFECTIVENESS
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2,000
2.500
4.000
6.000
8.000
Heat
Rate.
Btu/hp-hi
8,050
8.050
7,830
7.830
7.700
7.700
7.470
7.470
7.440
7.440
7.110
7.110
6.800
6.800
Hours
Per
Year
8.000
8,000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
Uncontrolled
NOx.
tonj/yr
11.1
20.9
34.8
4S.7
69.6
90.5
US
167
223
278
348
557
835
1110
NOx
Reduction.
%
90
90
90
90
90
90
90
90
90
90
90
90
90
90
Controlled
NOx,
tons/yr
1.11
2.09
3.48
4.87
6.96
9.05
11.8
16.7
22.3
27.8
34.8
55.7
835
111
NOx
removed.
tons/yr
10.0
18.8
31.3
438
62.6
814
106
150
200
250
313
501
751
1,000
Total
annual
cost. $
69.300
70.900
73,300
75.600
79,100
82,600
87,000
95.100
104,000
114.000
124,000
158.000
200.000
244,000
Cost
effectiveness.
I/ton NOx
removed
6.920
3,780
2,340
1.730
1.260
1.010
817
633
521
454
395
315
266
244
B-7
-------
TABLE B-7. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF LOW-
EMISSION COMBUSTION TO A MEDIUM-SPEED, RICH-BURN OR LEAN-BURN SI
ENGINE
CAPITAL COSTS
Power
Output,
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Power
Output,
hp
80
150
250
350
500
650
850
1.200
1.600
ZOOO
2.500
4.000
6.000
8.000
Heat
Rate.
Bru/hp-hr
8.140
8.140
7.820
7,820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Heat
Rate.
Btu/hp-hr
8.140
8.140
7.820
7.820
7.540
7,540
7.540
7.460
7.460
7.460
6.780
6.780
6,680
6.680
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8,000
8,000
8.000
8.000
8.000
8.000
Hours
Per
Year
8.000
8,000
8.000
8.000
8.000
8.000
8,000
8,000
8,000
8,000
8.000
8,000
8.000
8,000
Capital
Equipment
Cost,$
Sales Tax
A. Freight.
S
22.500 1.800
29.900 2.390
40,500 3,240
51.100 4.090
67.000 5,360
82,800 6.630
104,000 8,320
141.000 11.300
183.000 14,700
226.000 18.100
279,000 22.300
437,000 35.000
649,000 51.900
861.000 68.800
ANNUAL COSTS
Maintenance.
S
2.250
2.990
4.050
5,110
6.700
8.280
10,400
14,100
18.300
22.600
27.900
43,700
64.900
86.100
Overhead.
S
1.350
1,790
2.430
3.060
4.020
4.970
6,240
8.460
11.000
13,500
16,700
26,200
38.900
51,600
Direct and
Indirect
Installation.
Contingency. S
14.600
19,400
26.300
33.200
43.500
53.800
67,600
91,700
119.000
147.000
181.000
284,000
422.000
559.000
Fuel
Penalty,
S
(215)
(403)
(646)
(904)
(1.240)
(1.620)
(2.120)
(2,960)
(3,940)
(4,930)
(5,600)
(8.960)
(13,200)
(17,650)
Total
Capital
Cost.$
38.900
51.700
70.100
88.400
116.000
143.000
180.000
244.000
317.000
390,000
482.000
757,000
1.120.000
1.490,000
Taxes,
Insurance,
Admin.,
$
1,560
2,070
2,800
3,530
4,630
5.730
7,200
9.760
12.700
15,600
19,300
30.300
44,900
59,600
Compliance
Test.
J
2,440
2.440
2.440
2,440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2,440
2,440
Capital
Recovery,
S
4,270
5.680
7,690
9,700
12,700
15,700
19.800
26,800
34.800
42,900
52.900
83.100
123.000
163,000
Total
Annual
Cost,
S
11.700
14.600
18.800
22,900
29,300
35.500
43,900
58.600
75.300
92.100
114.000
177.000
261.000
346.000
COST EFFECTIVENESS
Power
Output,
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Heat
Rate.
Btu/hp-hr
8,140
8.140
7,820
7.820
7.540
7.540
7,540
7.460
7.460
7.460
6,780
6.780
6.680
6,680
Hours
Per
Year
8,000
8,000
8,000
8,000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8,000
Uncontrolled
NOx.
tons/yr
11.1
20.9
34.8
48.7
69.6
90.5
118
167
223
278
348
557
835
1110
Controlled
NOx.
g/hp-hr
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
20
2.0
20
20
2.0
Controlled
NOx.
tons/yr
1.41
2.64
4.41
6.17
8.81
11.5
15.0
21.1
28.2
35.2
44.1
70.5
106
141
NOx
removed.
tons/yr
9.72
18.2
30.4
42.5
60.8
79.0
103
146
194
243
304
486
729
972
Total
annual
cost,$
11,700
14.600
18.800
22,900
29300
35.500
43.900
58.600
75300
92.100
114,000
177,000
261.000
346.000
Cost
effectiveness
$Aon NOx
removed
1.200
799
618
539
481
450
425
402
387
379
374
364
358
355
B-8
-------
TABLE B-8. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF LOW-
EMISSION COMBUSTION TO A LOW-SPEED, RICH-BURN OR LEAN-BURN SI
ENGINE
CAPITAL COSTS
Power
Output.
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Power
Output,
hp
80
150
250
350
500
650
850
1.200
1.600
2.000
2.500
4.000
6.000
8.000
Heat
Rate.
Btu^p-^l^
8.140
8.140
7.820
7.820
7.540
7.540
7.540
7.460
7.460
7.460
6.780
6.780
6.680
6.680
Heat
Rate.
Btu/hp-hr
8.140
8,140
7.820
7,820
7.540
7.540
7.540
7,460
7.460
7,460
6.780
6.780
6.680
6.680
Hours
Per
Year
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
8.000
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8,000
8,000
8.000
8.000
Capital
Equipment
Cost,S
Sales Tax
& Freight,
$
198.000 15.800
21ZOOO 17.000
232,000 18,600
253,000 20.200
283.000 22.600
313.000 25,000
353.000 28.300
424,000 33.900
504,000 40.400
585,000 46.800
686.000 54.900
988.000 79,000
1.390.000 111.000
1.790.000 144,000
ANNUAL COSTS
Maintenance,
$
19,800
21.200
23,200
25,300
28,300
31.300
35.300
42,400
50.400
58,500
68.600
98,800
139,000
179.000
Overhead.
$
11.900
1Z700
13.900
15.200
17.000
18.800
21.200
25,400
30,300
35,100
41.100
59,300
83.500
108,000
Direct and
Indirect
Installation.
Contingency, $
129,000
138.000
151.000
164.000
184.000
203.000
230,000
275,000
328,000
380.000
446,000
642.000
904.000
1,170.000
Fuel
Penalty.
$
(215)
(403)
(646)
(904)
(1.240)
(1.620)
(2.120)
(2.960)
(3.940)
(4.930)
(5,600)
(8.960)
(13.200)
(17.600)
Total
Capital
Co«, $
343.000
367.000
402.000
437.000
489,000
541.000
611,000
733,000
873,000
1.010,000
1.190,000
1.710.000
2.410.000
3.100.000
Taxes.
Insurance,
Admin.,
$
13,700
14,700
16,100
17.500
19,600
21.700
24.400
29.300
34,900
40,500
47,500
68,400
96,300
124,000
Compliance
Test,
$
2.440
2.440
2,440
2,440
2,440
2,440
2.440
2.440
2,440
2,440
Z440
2.440
Z440
Z440
Capital
Recovery,
$
37.600
40,300
44,100
48.000
53,700
59,400
67,100
80.500
95,800
111.000
130.000
188.000
264,000
341.000
Total
Annual
Cost.
$
85,300
91.000
99.200
107.000
120.000
132.000
148.000
177,000
210.000
243.000
284.000
408.000
572.000
737,000
COST EFFECTIVENESS
Power
Output,
hp
80
150
250
350
500
650
850
1,200
1.600
ZOOO
2,500
4,000
6,000
8.000
Heat
Rate,
BtWhp-hr
8.140
8.140
7,820
7,820
7.540
7.540
7,540
7,460
7,460
7.460
6,780
6.780
6.680
6.680
Houn
Per
Year
8,000
8.000
8,000
8,000
8.000
8.000
8.000
8.000
8,000
8,000
8,000
8,000
8,000
8.000
Uncontrolled
NOx,
tons/yr
11.1
20.9
34.8
48.7
69.6
90.5
118
167
223
278
348
557
835
1110
Controlled
NOx.
g/hp-hr
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Controlled
NOx,
tons/yr
1.41
2.64
4.41
6.17
8.81
11.5
15.0
21.1
28.2
35.2
44.1
70.5
106
141
NOx
removed.
tons/yr
9.72
18.2
30.4
42.5
60.8
79.0
103
146
194
243
304
486
729
972
Total
annual
cost,J
85300
91,000
99.200
107.000
120,000
132,000
148.000
177,000
210,000
243,000
284.000
408,000
572,000
737,000
Cost
effectiveness.
SAon NOx
removed
8,770
4,990
3.260
2,520
1.970
1,670
1.440
1,210
1.080
998
936
838
785
758
B-9
-------
TABLE B-9. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF AN
AUTOMATIC A/F CONTROL SYSTEM TO A LEAN-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
200
350
550
800
1.350
1.550
2.000
2.500
3.500
5.500
8.000
9.500
11.000
Power
Output,
hp
200
350
550
800
1.350
1.550
2.000
2.500
3.500
5.500
8.000
9.500
11.000
Heat
Rate.
Btu/hp-hr
8.760
8.760
7,660
7.660
7.490
7.490
7.490
7.020
7.020
6.660
6.660
6.660
6.660
Heat
Rate.
Btu/hp-hr
8.760
8,760
7.660
7,660
7.490
7,490
7,490
7.020
7.020
6.660
6.660
6.660
6.660
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Capital
Equipment
CostS
Sales Tax
* Freight.
S
42.700 3.410
43.100 3.450
43.700 3,500
44,500 3.560
46.100 3.690
46.700 3.740
48.100 3.840
49.600 3,960
52.600 4,200
58.600 4.680
66.100 5.280
70.600 5.640
75.100 6,000
ANNUAL COSTS
Maintenance,
$
4,270
4.310
4.370
4.450
4.610
4.670
4.810
4.960
5.260
5.860
6.610
7.060
7.510
Overhead,
S
2.560
2.590
2.620
2.670
2,770
2.800
2.880
2,970
3.150
3,510
3,960
4.230
4.500
Direct and
Indirect
Installation,
Contingency. S
27.700
28.000
28.400
28.900
30.000
30.400
31.200
32.200
34.200
38.100
42.900
45.900
48.800
Fuel
Penalty,
$
1.740
3.040
4.170
6.070
10,000
11,500
14.800
17,400
24.300
36.300
5Z800
62.700
72,600
Total
Capital
CostS
73.800
74.600
75.600
76.900
79,800
80.800
83.100
85.700
90.900
101.000
114.000
122.000
130,000
Taxes,
Insurance.
Admin..
S
2.950
2,980
3.020
3.080
3,190
3,230
3,330
3.430
3.640
4.050
4.570
4.880
5,190
Compliance
Test,
S
2,440
Z440
Z440
2,440
Z440
Z440
Z440
Z440
Z440
Z440
Z440
Z440
Z440
Capital
Recovery,
S
8,100
8,190
8,300
8.440
8,760
8,870
9.130
9,410
9.980
11,100
12.500
13.400
14.300
Total
Annual
Cost.
$
22,100
23.500
24,900
27.100
31,800
33300
37.400
40.600
48.800
63.300
82.900
94.700
106,000
COST EFFECTIVENESS
Power
Output.
hp
200
350
550
800
1.350
1.550
2.000
2.500
3.500
5.500
8.000
9.500
11.000
Hex
Rate.
Btu/hp-hr
8.760
8.760
7.660
7.660
7.490
7.490
7.490
7.020
7,020
6.660
6.660
6.660
6,660
Hours
Per
Year
8,000
8.000
8.000
8,000
8,000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
8.000
Uncontrolled
NOx,
toni/yr
29.6
51.7
81.3
118
200
229
296
370
517
813
1180
1400
1630
NOx
reduction.
%
20
20
20
20
20
20
20
20
20
20
20
20
20
Controlled
NOx.
tons/yr
23.7
41.4
65.1
94.6
160
183
237
296
414
651
946
1120
1300
NOx
removed.
tons/yr
5.91
10.3
16.3
23.7
39.9
45.8
59.1
73.9
103
163
237
281
325
Total
annual
cost. J
22.100
23,500
24.900
27,100
31.800
33.500
37,400
40,600
48,800
63.300
82.900
94.700
106,000
Cost
effectiveness,
S/ton NOx
removed
3,730
2,270
1.530
1,150
796
731
633
549
472
389
350
337
327
B-10
-------
TABLE B-10. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF AN
ELECTRONIC IGNITION SYSTEM TO A LEAN-BURN SI ENGINE
CAPITAL COSTS
Power
Output.
hp
200
350
550
800
800
1.350
1.550
2.000
2.500
2.500
3.500
5.500
8.000
9.500
11.000
Power
Output.
hp
200
350
550
800
800
1.350
1.550
2.000
2.500
2.500
3.500
5.500
8.000
9.500
11.000
Heal
Rate.
Btu/hp-hr
8.760
8.750
7.560
7.550
7.660
7.490
7,490
7.490
7.020
7.020
7.020
6.550
6.660
6.660
6.660
Heat
Rate.
Btu/hp-hr
8.750
8.760
7,660
7,660
7.660
7.490
7.490
7.490
7.020
7.020
7.020
6.650
6.660
6.660
6.660
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8,000
8.000
8.000
8,000
8.000
Houn
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
Capital
Equipment
Cost. $
Sales Tax
& Freight.
S
7,500 600
7.500 600
7,500 600
7,500 600
10.000 800
10.000 800
10,000 800
10,000 800
10.000 800
15,000 UOO
15.000 1,200
15,000 1.200
15.000 UOO
15,000 1.200
15.000 UOO
ANNUAL COSTS
Maintenance.
$
750
750
750
750
1.000
1.000
1.000
1.000
1.000
1.500
1,500
1,500
1.500
1.500
1,500
Overhead.
$
450
450
450
450
600
600
600
600
600
900
900
900
900
900
900
Indirect Total
Instillation. Capital
Contingency. $ Cost. $
4.130
4.130
4.130
4.130
5.500
5.500
5.500
5.500
5.500
8.250
8.250
8250
8.250
8.250
8^50
Fuel
Penalty.
$
1.740
3,040
4.170
6.070
6.070
10,000
11,500
14,800
17.400
17,400
24.300
36.300
52.800
62,700
72.600
12.200
12.200
12.200
12200
16.300
16.300
16.300
16.300
16.300
24,500
24,500
24.500
24.500
24.500
24.500
Taxes.
Insurance,
Admin..
$
489
489
489
489
652
652
652
652
652
978
978
978
978
978
978
Compliance
Test.
S
2.440
2.440
2,440
2.440
2.440
2.440
2,440
2.440
2.440
2.440
2,440
2.440
2.440
2.440
2.440
Capital
Recovery.
S
1.340
1.340
1,340
1.340
1.790
1,790
1.790
1,790
1,790
2.680
2.680
2.680
2.680
2.680
2.680
Total
Annual
Cost,
J
7210
8.510
9.640
11.500
12.600
16.500
18.000
21.300
23.900
25.900
32.800
44.800
61,300
71,200
81.100
COST EFFECTIVENESS
Power
Output,
hp
200
350
550
800
800
1.350
1,550
2.000
2,500
2.500
3.500
5.500
8.000
9.500
11.000
Heat
Rate.
Btu/hp-hr
8,760
8.760
7,660
7.660
7,660
7.490
7.490
7,490
7,020
7,020
7.020
6.660
6.660
6.660
6.660
Houn
Per
Yew
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
Uncontrolled
NOx,
lont/yr
29.6
51.7
81.3
118
118
200
229
2%
370
370
517
813
1180
1400
1630
NOx
reduction.
%
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
Controlled
NOx.
ton»/yr
26.6
46.6
73.2
106
106
ISO
206
266
333
333
466
732
1060
1260
1460
NOx
removed.
toru/yr
2.96
5.17
8.13
11.8
11.8
20.0
22.9
29.6
37.0
37.0
51.7
81.3
118
140
163
Total
annual
cost. J
7.210
8.510
9.640
11400
12.600
16.500
18.000
21300
23,900
25.900
32.800
44.800
61.300
71000
81,100
Cost
effect! venesi
S/lonNOx
removed
2.440
1.640
1,190
976
1.060
827
785
721
646
700
635
551
518
507
499
B-ll
-------
TABLE B-ll. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF
AUTOMATIC A/F CONTROL AND ELECTRONIC IGNITION SYSTEMS TO A LEAN-
BURN SI ENGINE
CAPITAL COSTS
Power
Outpui.
hp
:oo
?50
550
goo
800
1.150
1,550
2.000
2.500
2.500
1.500
5.500
8.000
9.500
11,000
Power
Output,
hp
200
350
550
800
800
1.350
1.550
2,000
2.500
2.500
3.500
5.500
8.000
9.500
11.000
Heal
Rate.
Btu/hp-hr
8.760
8.760
7.660
7,660
7.660
7.490
7,490
7.490
7.020
7.020
7.020
6.660
6,660
6.660
6.660
Heal
Rate.
Btu/hp-hr
8.760
8.760
7.660
7.660
7.660
7.490
7,490
7,490
7.020
7.020
7.020
6.660
6.660
6.660
6.660
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
Houn
Per
Year
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8,000
Capital
Equipment
CosuS
Sales Tax
* Freight.
$
50.200 4.010
50.600 4.050
51.200 4.100
52,000 4.160
54.500 4.360
56.100 4.490
56.700 4.540
58.100 4.640
59.600 4.760
64.600 5.160
67.600 5.400
73.600 5,880
81.100 6.480
85.600 6.840
90.100 7.200
ANNUAL COSTS
Maintenance.
$
5.020
5.060
5.120
5.200
5.450
5.610
5.670
5,810
5.960
6.460
6.760
7.360
8.110
8.560
9,010
Overhead.
J
3.010
3.040
3.070
3.120
3.270
3.370
3,400
3.480
3.570
3.870
4.050
4.410
4.860
5.130
5.400
Direct and
Indirect
InstaUaoon.
Contingency. S
30.100
30.400
30.700
31.200
32.700
33.700
34.000
34.800
35.700
38.700
40.500
44.100
48.600
51.300
54.000
Fuel
Penalty,
S
2.890
5.060
6.960
10,100
10,100
16.700
19.200
24.700
29.000
29.000
40.600
60.500
88.000
104.000
121.000
Total
Capital
Cost. $
84.300
85.000
86.000
87.300
91.500
94.300
95,300
97.500
100.000
108.000
113.000
124.000
136.000
144.000
151.000
Taxes.
Insurance.
Admin..
S
3.370
3.400
3.440
3.490
3.660
3.770
3.810
3.900
4.000
4.340
4.540
4.940
5.450
5.750
6.050
Compliance
Test,
S
2.440
2.440
2.440
2.440
2.440
2.440
2,440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
Capital
Recovery.
$
9.250
9.330
9.440
9.580
10.000
10.300
10.500
10.700
11.000
11.900
12.500
13,600
15,000
15.800
16.600
Total
Annual
Cost.
S
26.000
28.300
30.500
33.900
35.000
42.200
44,900
51.100
55,900
58.000
70.800
93.200
124.000
142.000
160.000
COST EFFECTIVENESS
Power
Output,
hp
200
350
550
800
goo
1,350
1.550
2,000
2,500
2,500
3.500
5.500
8.000
9.JOO
11.000
Heat
Rate.
BtuAp-hr
8.769
8.760
7.660
7.660
7.660
7.490
7.490
7,490
7,020
7.020
7,020
6.660
6.660
6,660
6.660
Houn
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Uncontrolled
NOx.
tom/yr
29.6
51.7
81.3
118
118
200
229
296
370
370
517
813
1180
1400
1630
NOx
reduction.
1c
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Controlled
NOx.
tons/vr
22.2
38.8
61.0
88.7
88.7
150
172
222
277
277
388
610
887
1050
1220
NOx
removed.
loni/yr
7.39
12.9
20.3
29.6
29.6
49.9
57.3
73.9
92.4
92.4
129
203
296
351
407
Total
annual
com J
26,000
28.300
30.500
33.900
35,000
42.200
44.900
51.100
55,900
58.000
70.800
93,200
124.000
142.000
160.000
Cost
effectrveoeis.
SAonNOx
removed
3.510
2.190
1300
1.150
1.180
846
785
691
605
628
547
458
419
405
395
B-12
-------
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B-13
-------
TABLE B-13. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF AN
ELECTRONIC INJECTION CONTROL SYSTEM TO A DIESEL ENGINE
CAPITAL COSTS
Power
Output
80
150
250
350
500
700
900
900
1.100
1.400
2.000
2.500
2.500
4.000
6.000
8.000
Power
Output
hp
80
150
250
350
500
700
900
900
1.100
1.400
2.000
2.500
2.500
4,000
6.000
8.000
Heat
Rate.
Bru/hp-nr
6.740
6.740
6.600
6.600
6.790
6.790
6.790
6.790
6.740
6.740
6.740
6.710
6.710
6.710
6200
6200
Heat
Rate.
Btu/hp-hr
6.740
6.740
6.600
6.600
6.790
6.790
6.790
6.790
6.740
6.740
6,740
6.710
6,710
6.710
6200
6200
Houn
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Houn
Per
Year
8.000
8.000
8.000
8.000
8.000
8,000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Capital
Eainnment
1 "I*™!
Co.1. $
Sales Tax
A Freight.
S
7.500 600
7.500 600
7.500 600
7.500 600
7.500 600
7.500 600
7.500 600
10.000 800
10.000 800
10.000 800
10,000 800
10.000 800
15.000 1.200
15.000 1,200
15,000 1.200
15.000 1.200
ANNUAL COSTS
Maintenance.
$
750
750
7<0
7?0
750
750
750
.000
.000
.000
.000
.000
.500
.500
.500
1,500
Overhead.
J
450
450
450
450
450
450
450
600
600
600
600
600
900
900
900
900
Direct and
Indirect
Installation.
Contingency. $
4.130
4.130
.130
.130
.130
.130
.130
5.500
5.500
5.500
5,500
5.500
8250
8250
8250
8250
Fuel
Penalty.
J
754
1.410
2.310
3230
4.750
6.650
8.550
8.550
10.400
13,200
18.800
23.500
23.500
37.500
52.000
69.400
Total
Capital
Cost. $
12.200
12.200
12200
12,200
12.200
12.200
12200
16.300
16.300
16.300
16.300
16,300
24.500
24.500
24.500
24.500
Taxes,
Insurance.
Admin.,
S
489
489
489
489
489
489
489
652
652
652
652
652
978
978
978
978
Compliance
Test.
$
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
2.440
Capital
Recovery.
$
1.340
1340
1.340
1.340
1.340
1.340
1.340
1,790
1,790
1,790
1.790
1.790
2.680
2,680
2.680
2.680
Total
Annual
Cost,
J
6230
6.880
7.780
8.700
10200
12.100
14.000
15.000
16.800
19.700
25300
29.900
32.000
46.000
60.500
77.900
COST EFFECTIVENESS
Power
Output
hp
80
150
250
350
500
700
900
900
1.100
1.400
2.000
2.500
2.500
4.000
6.000
8.000
Heat
Rate.
Btu/hp-hr
6.740
6,740
6.600
6.600
6,790
6,790
6,790
6,790
6.740
6,740
6.740
6.710
6.710
6,710
6200
6200
Houn
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Uncontrolled
NOx.
tons/yr
S.45
15.1
26.4
36.9
518
73.9
95.0
95.0
116
148
211
264
264
422
633
845
NOx
reoucDOB.
*
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Controlled
NOx,
tons/yr
6.33
11.9
19.8
27.7
39.6
55.4
71.3
71.3
87.1
111
158
198
198
317
475
633
NOx
removed.
lons/yr
2.11
3.%
6.60
9.24
13.2
18.5
23.8
23.8
29.0
36.9
52.8
66.0
66.0
106
158
211
Total
annual
cost, J
6230
6.880
7.780
8.700
10200
12,100
14.000
15.000
16.800
19.700
25.300
29,900
32,000
46.000
60.500
77,900
Cost
effecnveoeu.
Won NOx
removed
2.950
1.740
1.180
942
774
656
590
633
580
533
480
454
484
436
382
369
B-14
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B-15
-------
TABLE B-15. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF AN
ELECTRONIC INJECTION CONTROL SYSTEM TO A DUAL-FUEL ENGINE
CAPITAL COSTS
Power
Output.
hp
700
900
900
1.200
1.650
2.200
2.200
4.000
6.000
8.000
Power
Output,
hp
700
900
900
1.200
1.650
2.200
2.200
4.000
6.000
8.000
Heat
Rate,
Btu/hp-hr
6,920
6.920
6.920
7.220
7.220
6.810
6.810
6,810
6.150
6.150
Heat
Rate.
Btu/hp-hr
6.920
6.9^0
6.920
7.220
7.220
6,810
6.810
6.810
6.150
6.150
Hours
Per
Year
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
8.000
Hours
Per
Year
8.000
8.000
8.000
8.000
8,000
8,000
8.000
8.000
8.000
8.000
Capita]
Equipment
Cost. 5
Sales Tax
& Freight,
S
7.500 600
7,500 600
10.000 800
10,000 800
10,000 800
10.000 800
15.000 1.200
15.000 1.200
15,000 1.200
15,000 1.200
ANNUAL COSTS
Maintenance,
S
750
750
,000
.000
.000
.000
.500
,500
,500
,500
Overhead,
S
450
450
600
600
600
600
900
900
900
900
Direct and
Indirect
Installation.
Contingency, S
4,130
4.130
5,500
5.500
5,500
5.500
8.250
8,250
8.250
8.250
Fuel
Penalty,
S
4.800
6.170
6.170
8,580
11.800
14.800
14.800
27,000
36.600
48,700
Total
Capital
Cost. $
12,200
12,200
16.300
16.300
16.300
16.300
24.500
24,500
24.500
24.500
Taxes.
Insurance,
Admin..
S
489
489
652
652
652
652
978
978
978
978
Compliance
Test.
S
2.440
2,440
2,440
2,440
2,440
2,440
2.440
2.440
2.440
2.440
Capital
Recovery,
S
,340
.340
.790
.790
,790
,790
2,680
2,680
2,680
2.680
Total
Annual
Cost.
S
10.300
11.600
12,700
15.100
18,300
21.300
23300
35.500
45.100
57,200
COST EFFECTIVENESS
Power
Output,
hp
700
900
900
1,200
1.650
2.200
2.200
4.000
6.000
8.000
Heat
Rate.
Btu/hp-hr
6.920
6.920
6.920
7,220
7.220
6.810
6,810
6.810
6,150
6,150
Hours
Per
Year
8,000
8,000
8.000
8,000
8,000
8,000
8,000
8.000
8.000
8.000
Uncontrolled
NOx,
tons/yr
52.1
67.0
67.0
89.4
123
164
164
298
447
596
NOx
reduction.
%
20
20
20
20
20
20
20
20
20
20
Controlled
NOx,
tons/yr
41.7
53.6
53.6
71.5
98.3
131
131
238
357
477
NOx
removed.
tons/yr
10.4
13.4
13.4
17.9
24.6
32.8
32.8
59.6
89.4
119
Total
annual
cost. S
10.300
11.600
12.700
15.100
18.300
21.300
23,300
35.500
45.100
57000
Cost
effectiveness.
S/tonNOx
removed
985
868
944
843
744
651
712
596
504
480
B-16
-------
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— — —
-------
TABLE B-17. COSTS AND COST EFFECTIVENESS FOR RETROFIT OF
LOW-EMISSION COMBUSTION TO A DUAL-FUEL ENGINE
CAPITAL COSTS
Power
Output.
hp
700
900
1.200
1.650
2.200
4.000
6.000
8.000
Power
Output.
hp
700
900
1.200
1.650
2.200
4.000
6,000
8.000
Heat
Rate.
Btu/hp-hr
6.920
6.920
7.220
7.220
6.810
6.810
6.150
6.150
Heat
Rate.
Btu/hp-hr
6,920
6.920
7.220
7.220
6.810
6.810
6,150
6,150
Hours
Per
Year
8,000
8.000
8,000
8,000
8,000
8.000
8,000
8.000
Hours
Per
Year
8,000
8.000
8,000
8,000
8,000
8.000
8.000
8.000
Capital
Equipment
Cost. S
Direct and
Sales Tax Indirect
& Freight. Installation,
S Contingency. S
416.000 33.300
468.000 37,400
546.000 43,700
663.000 53,000
806.000 64,500
1.270,000 102,000
1,790.000 144.000
2,310,000 185.000
ANNUAL COSTS
Maintenance.
S
41.600
46,800
54.600
66.300
80.600
127.000
179.000
231.000
Overhead,
$
25.000
28.100
32.800
39.800
48.400
76,400
108,000
139.000
270,000
304.000
355.000
431.000
524,000
828,000
1,170.000
1.500,000
Fuel
Penalty,
S
4,800
6,170
8.580
11.800
14,800
27.000
36,600
48,700
Total
Capital
Cost. $
720,000
810,000
945.000
1,150,000
1,390,000
2.200.000
3,100.000
4.000,000
Taxes,
Insurance,
Admin.,
S
28.800
32,400
37.800
45.900
55.800
88.200
124,000
160.000
Compliance
Test.
S
2.440
2.440
Z44C.
2,440
2,440
2,440
2.440
2,440
Capital
Recovery,
S
79,000
88,900
104.000
126,000
153.000
242,000
341.000
440.000
Total
Annual
Cost.
S
182.000
205.000
240.000
292.000
355.000
563.000
791,000
1.020.000
COST EFFECTIVENESS
Power
Output,
hp
700
900
1.200
1.650
2.200
4.000
6.000
8.000
Heat
Rate.
Btu/hp-hr
6,920
6.920
7.220
7.220
6.810
6.810
6.150
6,150
Hours
Per
Year
8.000
8.000
8,000
8,000
8.000
'8,000
8,000
8,000
Uncontrolled
NOx,
tons/yr
52.1
67.0
89.4
123
164
298
447
5%
Controlled
NOx.
g/hp-hr
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Controlled
NOx.
tons/yr
12.3
15.9
21.1
29.1
38.8
70.5
106
141
NOx
removed.
tons/yr
39.8
51.2
68.2
93.8
125
227
341
455
Total
annual
costS
182.000
205,000
240,000
292.000
355.000
563,000
791,000
1.020.000
Cost
effectiveness.
S/ton NOx
removed
4,560
4,000
3.520
3,110
2,840
2.480
2.320
2040
B-18
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing/
1 REPORT NO. 2.
EPA-453/R-93-032
4. TITLE AND SUBTITLE
Alternative Control Techniques Document-
NOX Emissions from Stationary Reciprocating
Internal Combustion Engines
7. AUTHOH(S)
Robert B. Snyder
9. PERFORMING ORGANIZATION NAME ANO ADDRESS
Midwest Research Institute
401 Harrison Oaks Boulevard
Gary, NC 27513-2412
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Emission Standards Division (MD-13)
Office of Air Quality Planning Standards
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
July 1993
6. PERFORMING ORGANIZATION CODE
a. PERFORMING ORGANIZATION REPORT NO
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D1-0115
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
is. SUPPLEMENTARY NOTES
EPA Work Assignment Manager: William Neuffer (919) 541-5435
6. ABSTRACT
This alternative control techniques (ACT) document describes
available control techniques for reducing NOX emission levels
from rich-burn and lean-burn natural gas-fired, diesel, and dual-
fuel stationary reciprocating internal combustion engines. A
discussion of the formation of NOX and uncontrolled emission
levels is included. Control techniques include parameter
adjustments, prestratified charge, selective and nonselective
catalytic reduction, and low-emission combustion. Achievable
controlled NOX emission levels, costs and cost effectiveness, and
environmental impacts are presented, and the applicability of
these control techniques to new equipment and retrofit
applications is discussed.
7 KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Reciprocating Internal Combustion
Engines
Nitrogen Oxide Emissions
Control Techniques for NOX Emissions
Costs of Emission Controls
Catalytic Reduction
Low-Emission Combustion
i. DISTRIBUTION STATEMENT
b. IDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS /Thu Report/
20 SECURITY CLASS (Tha page)
c. COSATI Field/Croup
21. NO. OF PAGES
315
22. PRICE
PA Form 2220-1 (R»». 4-77) PREVIOUS EDITION is OBSOLETE
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