EPA-600/7-90-001
(January 1990
DESIGN REPORT:
LOW-NOx BURNERS FOR PACKAGE BOILERS
by
R. A. Brown, H. Dehne, S. Eaton, H. B. Mason, and S. Torbov
Acurex Corporation
Environmental Systems Division
485 Clyde Avenue
P.O. Box 7044
Mountain View, California 94039
EPA Contract No. 68-02-4213
EPA Project Officer: William P. Linak
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
Air and Energy Engineering Research Laboratory
Office "of Research and Development
0.S. Environmental Protectiori;Agency -
Research-triangle Park,"NC"27711
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/7-90-001
3. RECIPIENT'S ACCESSION NO. ~
PB"90' 1 5 9 8 98 fAS
4. TITLE AND SUBTITLE
Design Report: Low-NOx Burners for Package
Boilers
5. REPORT DATE
January 1990
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
R.A.Brown, H.Dehne, S. Eaton, H. B. Mason, and
S. Torbov
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Acurex Corporation
P.O. Box 7044
Mountain View, California 94039
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-4213
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory-
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 5/85 - 3/89
14. SPONSORING AGENCY COOE
EPA/600/13
is. supplementary notes ^EERL project officer is William P. Linak, Mail Drop 65, 919/
541-5792.
16. abstract rep0rt describes a low-NOx burner design, presented for residual-oil-
fired industrial boilers and boilers cofiring conventional fuels and nitrated hazar-
dous wastes. The burner offers lower NOx emission levels for these applications
than conventional commercial burners. The burner utilizes two-stage combustion in
a deep staging mode in which a precombustor firing substoichiometrically is retro-
fitted to the front of the boiler. The completion of the combustion in the second
stage is achieved through sidefire air ports to be retrofitted to the boiler. The pre-
combustor is a cylindrical shell of 2.1 m internal diameter fabricated of lightweight
refractory blocks with a Saffil based coating. This material gives a lightweight, non-
regenerative precombustor which can adapt to the start-up, shutdown, and load fol-
lowing transients typical of industrial boilers. The precombustor is designed for the
capacity range of 15-29 MW heat input. A modular design using annular spool sec-
tions adapts to different design loads within this range. For larger loads, a geomet-
ric scale-up is required. Design data are also given for 59 MW capacity. .
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDEDTERMS
c. COS ATI Field/Group
Pollution
Fuel Oil
Combustion Control
Nitrogen Oxides
Boilers
Pollution Control
Stationary Sources
Combustion Modification
Low-NOx Burners
13 B
21D
21B
07B
13 A
18. DISTRIBUTION STATEMENT
^ NTIS Is authorized to reproduce and sell this
Release to Pud lie report. Permission lor lurther reproduction
must be obtained (rom the copyright owner.
19. SECURITY CLASS (This Report)
Unclassified
21. SK3. OF PAGES
' 14T;
20. SECURITY CLASS (This page)
Unclassified
22. PRICE"
ui
EPA Form 2220-1 (9-73)
rr
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NOTICE
This document has been reviewed in accordance with
U.S. Environmental Protection Agency policy and
approved for publication. Mention of trade names
or commercial products does not constitute endorse-
ment or recommendation for use.
ii
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ACKNOWLEDGMENT
The participation of Mr. Eaton in this project was arranged through a subcontract from
Acurex Corporation to the Coen Company. The contribution of Mr. Eaton and the
Coen Company to this report and to the design of the low-NOx burner are gratefully
acknowledged.
A low-NOx burner design is presented for residual oil-fired industrial boilers and boilers
cofiring conventional fuels and nitrated hazardous wastes. The burner is intended for higher
NOx emission reductions for these applications than conventional commercial burners. The
burner utilizes two stage combustion in a deep staging mode in which a precombustor firing
substoichiometrically is retrofitted to the front of the boiler. This firing configuration promotes
chemical decomposition of fuel nitrogen compounds in the hot, fuel-rich first stage pre-
combustor. The completion of the combustion in the second stage is achieved through sidefire
air ports to be retrofitted to the boiler. For the prototype design, stage air can also be injected
axially or radially at the throat section between the precombustor and boiler.
The precombustor is a cylindrical shell of 2.1 m (7 ft) internal diameter fabricated of
lightweight refractory blocks with a Saffil™ based coating. This material gives a lightweight,
nonregenerative precombustor which can adapt to the start-up, shutdown, and load following
transients typical of industrial boilers.
Precombustor designs are described for the capacity range of 15 to 59 MW (50 to 200
MMBtu/hr) heat input. A modular design using annular spool sections adapts to different
design loads in the range of 15 to 29 MW (50 to 100 MMBtu/hr). For larger loads, a geometric
scale-up is required. TTie burner used with the precombustor is a conventional register burner.
Separate atomizer guns are provided for residual oil and nitrated waste firing. The burner also
has gas firing capability. The control system maintains precombustor stoichiometry at the
conditions for optimum NOx reduction and the temperature limits of the refractory. Light-off
is done at fuel-lean conditions by bypassing stage air to the precombustor until stable
temperatures are reached. During normal staged operation, load following is done by
proportional controlling of fuel, primary air, and stage air. Waste fuel firing is controlled
consistent with the proposed boiler cofiring regulations whenever the boiler load exceeds
25 percent of capacity and waste firing contributes less than 50 percent of total heat input.
This report presents the burner design and sub-scale refractory endurance tests. No
field evaluations have been performed.
ABSTRACT
111
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CONTENTS
Acknowledgements ,iii j
Abstract i i i i i
Figures vi i
Tables
1. Introduction 1
1.1 Background 1
1.2 Design Objectives 2
1.3 Approach 4
2. Conceptual Design 5
2.1 Technical Options 5
2.2 Configuration Tradeoffs 10
2.2.1 Performance Data and Calculations 10
2.2.2 Configuration Selection: 15 MW (50 MMBtu/hr) Thermal Input 21
2.2.3 Configuration Selection: 59 MW (200 MMBtu/hr) 22
2.3 Refractory Concept for the Fully Insulated Design 22
2.4 Refractory Concept for the Regenerable Design 29
3. Combustor and Retrofit Design 37
3.1 Burner 38
3.2 First Stage Precombustor Detail 38
3.3 Boiler Interface 44
3.4 Control System and Data Acquisition 45
3.4.1 Introduction 45
3.4.2 Control Strategy 45
3.4.3 Start-up, Operation, and Shutdown Control Sequence 48
3.4.4 Data Acquisition 49
3.4.5 Control System Specification 50
3.4.6 Control System Requirements 50
3.4.7 Product Control System 54
4. Conclusions 56
v
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CONTENTS (concluded)
References 58
Abbreviations 59
Appendix A ~ Site Selection 60
Appendix B -- Subscale Refractory Endurance Tests 88
Appendix C -- Design Drawings 119
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FIGURES
Number Page
1 Oil-fired NOx controls 3
2 Prototype EOR burner 6
3 EOR low-NOx burner retrofit 7
4 Chemical kinetics for TFN and NO for simulated fuel CH4 with 1% N
as HCN 11
5 TFN data for different combustors 13
6 Flue gas analysis for different stoichiometrics 14
7 Combustor temperatures 15
8 Air staging temperature profiles: 15 MW (50 MMBtu/hr) boiler 16
9 Combustor-boiler firebox TFN decay process 18
10 NOx formation and prediction. . 19
11 Solid burden from gasifier with steam atomization 20
12 Solid burden from gasifier with air atomization 20
13 Bacharach soot concentration g/Nm3 flue gas 21
14 Pyro-Bloc Plus module 23
15 Combustor cross section, Pyro-Bloc Plus module arrangement 25
16 Heat transfer through the cylindrical wall 28
17 Combustor front end plate and wall assembly 30
18 Combustor rear wall throat design 31
19 Regenerative low-NOx combustor design: 59 MW (200 MMBtu/hr)
capacity 35
20 Heat transfer scheme regenerative design 36
21a Process diagram - English units 39
21b Process diagram - S.I. units 40
22 The combustor section 41
23 Example register burner 42
24 Example atomizer 43
25 Typical fuel train 47
A-l Sample letter sent to industrial clients 72
A-2 Field evaluation of low-NOx heavy oil burners applied to industrial
packaged boilers 74
B-l EPA package boiler simulator 89
B-2 Refractory response to durability testing 95
B-3 Transient bore temperatures (Tl)—1-19-89 104
B-4 Transient inner spool temperatures (T2)—1-19-89 104
B-5 Transient bore temperatures (Tl)—1-20-89 105
B-6 Transient inner spool temperatures (T2)—1-20-89 105
B-7 Transient bore temperatures (Tl)—1-23-89 106
B-8 Transient inner spool temperatures (T2)—1-23-89 106
1
1
I
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FIGURES (Concluded)
Number 1 Page
B-9 Transient bore temperatures (Tl)—1-24-89 107
B-10 Transient inner spool temperatures (T2)—1-24-89 107
B-ll Transient bore temperatures (Tl)—1-25-89 108
B-12 Transient inner spool temperatures (T2)—1-25-89 108
B-13 Bore temperatures (Tl)—2-15-89 113
B-14 Inner spool temperatures (T2)—2-15-89 113
B-15 Bore temperatures (Tl)—2-16-89 114
B-16 Inner spool temperatures (T2)—2-16-89 114
B-17 Bore temperatures (Tl)—2-21-89 115
B-18 Inner spool temperatures (T2)—2-21-89 115
B-19 Bore temperatures (Tl)—2-22-89 116
B-20 Inner spool temperatures (T2)—2-22-89 116
B-21 Bore temperatures (Tl)—2-23-89 117
B-22 Inner spool temperatures (T2)—2-23-89 118
TABLES
Number Page
1 Adiabatic and predicted flame temperature 16
2 Kao-plus C85 casting plastic monolith-average properties 32
3 Lightweight castable physical properties 33
4 Unistik cement 34
5 Summary of input/output signals for low-NOx burner system 51
A-l Site selection criteria 61
A-2 Industry trade association contacts 63
A-3 Air pollution regulatory agency contacts 64
A-4 Nitrated compound manufacturers 66
A-5 Industry contacts 82
A-6 Military and government contacts 85
A-7 Boiler specifications for high priority sites 86
B-l Durability testing operating log 91
B-2 Steady state endurance testing (Phase I) 96
B-3 Transient operation occurring during Phase I 97
B-4 Transient testing of lightweight refractory spool—emissions 98
B-5 Transient testing of lightweight refractory spool—temperatures 103
B-6 Failure testing of lightweight refractory spool—emissions 110
B-7 Failure testing of lightweight refractory spool—temperatures 112
v i i i
v.
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SECTION 1
INTRODUCTION
1.1 BACKGROUND
The development of the low-NOx burner design reported here was motivated by two
separate regulatory needs for more effective NOx emission reduction. The first need addressed
by the burner is for additional emission control for industrial boilers firing high nitrogen residual
oil. This requirement is based on the intent of the Clean Air Act (CAA) to periodically
introduce successively lower emission control standards for new sources as part of Section 111
of the Act.
The initial set of new source performance standards (NSPS) for industrial boilers was
proposed on June 19, 1984 and revised and promulgated on November 25, 1986.1 The NO
standard for residual oil-fired package boilers (heat release rate greater than 730,000 J/sm
(70,000 Btu/hr ft3)) was set at 170 ng/J expressed as N02 (0.40 lb/MMBtu as N02). This
emission level is equivalent to about 310 ppm corrected to 3 percent oxygen. This level is
30 percent higher than the earlier NSPS set for residual oil-fired utility boilers of 129 ng/J
(0.3 lb/MMBtu as N02). The NOx standard for industrial boilers with lower heat release (less
than 730,000 J/s m3 (70,000 Btu/hr ft3)) is the same as the earlier utility boiler standard.
The reason for the higher NOx emission standard for industrial package boilers was that
there was a lack of demonstrated technology which could effectively reduce industrial boiler
emissions for the compact package boiler design, without introducing operational problems.
Conventional technologies such as commercial low-NOx burners and sidefire air generally
increase flame length. For package boilers, this can lead to tubewall flame impingement since
the firebox dimensions are tight to permit boiler shipment by rail or barge.
The 1970 and 1977 CAA Amendments require EPA to periodically review the NSPS and
revise the emission standards based on technology developments since the prior review. To
support this type of review for residual oil fired industrial boilers, EPA's Office of Air Quality
Planning and Standards (OAQPS) identified the need for a combustion modification technology
capable of achieving improvement on the current technology for residual oil fired industrial
boilers. Although there was no precise emission level which must be achieved, an emission target
level of 100 to 125 ppm was suggested by OAQPS for the burner development.
The second regulatory need addressed by the burner development arises from the intent
of the Resource Conservation and Recovery Act (RCRA) to promote hazardous waste disposal
alternatives to landfill. For liquid combustible wastes, thermal destruction by either cofiring with
conventional fuels in boilers or by direct incineration can be an efficient disposal alternative
while recovering energy from the waste.
1
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A potential conflict between the CAA and RCRA can arise for those RCRA
Appendix VIII compounds and waste categories which contain nitrogen. There are 30 category
F and K listings and 114 Appendix VIII compounds, including nitriles, amines, nitrobenzene, and
cyanides, which contain bound nitrogen. These wastes may contain nitrogen levels of 10 percent
or more. Thermal destruction without extensive NO^ control can increase NOx emissions by
several hundred parts per million relative to conventional fuels. Uncontrolled emissions may
reach 1,000 ppm (Figure 1).
The control of NOx from nitrated waste thermal destruction is complicated by the
simultaneous need for low-NOx and high thermal destruction. For conventional combustion,
these are generally opposed conditions. The combustion environment which favors high thermal
destruction is high temperature, intense mixing, and long residence time in the hot zone. This
environment, however, also favors NOx formation in conventional combustion. Conventional
approaches to NOx control can, therefore, be counterproductive for thermal destruction
performance. The need addressed by the burner development was to control NOx formation
from nitrated waste thermal destruction while not degrading, and possibly improving, waste
destruction efficiency.
No firm emission control goal was set since the regulatory need was to avoid high
emission increases with cofiring rather than to achieve any specific compliance level.
Qualitatively, the goal was to fire wastes with nitrogen levels as high as 10 percent and
experience emissions comparable to or lower than conventional combustion when firing residual
011 under uncontrolled conditions.
12 DESIGN OBJECTIVES
The objective of this project was to design an industrial boiler low-NOx burner for firing
residual oil or cofiring nitrated waste. The quantitative design objectives are listed below. In
addition to the quantitative goals are several qualitative goals relating to the impact of the
burner on boiler operation. These goals are motivated by the potential constraining effects of
modified low-NOx conditions on boiler operational flexibility. The performance goals used for
the burner design were:
• Fuels: high nitrogen residual oil
Nitrated waste cofired with residual oil
Natural gas and distillate oil for light-off and backup
• NOx emissions: 100 to 125 ppm with residual oil
200 to 300 ppm with nitrated waste cofiring
• Carbon monoxide: <35 ppm
• Smoke emissions: <4 Bacharach number
• Capacity: 15 to 59 MW (50 to 200 MMBtu/hr) thermal input
• Boiler application: retrofit or new source application for major design types (D,
A, and O) of single burner boilers
• Turndown: >5:1
• Destruction efficiency with waste firing: >99.99 percent
• Operational flexibility: startup, shutdown, and load following transients
comparable to conventional burners
• Size: minimal constraint on retrofit space requirements
• Burner controls: integrated to existing boiler controls in retrofit application
• User oriented
2
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u>
40
10
0.1
EPA Low NO* Burner
Residual
Oil
Waste
Cofiring
J L
0.2
0.4 0.6 0.8 1.0 2.0
Fuel N (percent)
Figure 1. Oil-fired NO^ controls.
_L
4.0 6.0 8.0 10.0
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The stated design objectives for burner heat input capacity are very broad. At the start of the
program, the design objective was focused on the upper end of the range of package boiler heat
input capacities: 59 MW to 74 MW (200 to 250 MMBtu/hr). This range was chosen because
the package boilers in the upper end of the capacity range exhibited the highest volumetric heat
release and hence the higher potential for operational problems with modified low NOx
combustion. This capacity range was regarded as the greatest challenge to achieving low NOx
emissions with acceptable operational impacts.
Early in the project, the design objective for capacity was lowered after initial boiler user
surveys showed there were few operators in the high end of the capacity range using residual
oil. The capacity design range was lowered to 37 MW (125__MMBtu/hr) to include a significant
number of boilers firing residual oil and still retain the emission reduction challenge inherent
in the original objective.
Further along in the project, the design objective for capacity was further lowered to
15 MW (50 MMBtu/hr) after surveys of nitrated waste generators showed that the lower
capacity boilers were used more frequently for nitrated waste cofiring than the larger package
boilers. The composite range of 15 to 59 MW was finally selected to give broad coverage of
both high nitrogen residual oil applications as well as cofiring of high nitrogen wastes. Across
the entire capacity range, the emphasis in the design was to achieve the performance goals with
minimum compromise on boiler operational flexibility.
13 APPROACH
At program inception, the intent was to carry the burner development through to the
field evaluation of a prototype full scale burner retrofit to an existing boiler firing residual oil,
and, as an option, cofiring nitrated waste. Consistent with this field hardware focus, a major
initial task in the program was the site survey to find an appropriate site for the field evaluation.
Seven months into the program, the funding was truncated to allow only design development
and supporting bench scale testing. Accordingly, the site survey effort was terminated and the
subsequent effort refocused on the conceptual design evaluations reported in Section 2 and the
detailed design development reported in Section 3. For completeness, the progress made in the
site selection is summarized in Appendix A. Data from supporting bench scale testing is
summarized in Appendix B. Because the funding was truncated, the intended field evaluation
was not conducted and the program concluded with the design effort and sub-scale endurance
testing reported herein.
The design reported here is for a prototype burner intended for the initial qualification
and optimization testing. As such, the design contains more flexibility in air and fuel distribution
and control and instrumentation than would be used in an eventual commercial burner. This
is particularly necessary in the current project, where it was the intent to proceed directly to a
field prototype checkout without pilot scale testing. Thus, testing of the overall burner
performance, materials behavior, and optimization of stoichiometry and air distribution would
need to be done with the first prototype article. After the initial prototype tests, the operational
characteristics of the burner would be known and the design could be simplified for routine
application.
4
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SECTION 2
CONCEPTUAL DESIGN
2.1 TECHNICAL OPTIONS
The present industrial boiler low-NOx burner development is an extension of an earlier
sequence of EPA burner development and scale-up projects. This developmental sequence
focussed on achieving low levels of NOx emissions during high-nitrogen oil firing through use of
an advanced degree of two-stage combustion.
The fundamental concepts underlying the burner design were developed in the 1970's,
and carried through to the hardware stage in the early 1980's in a series of scale-up tests.
Sarofim2 in 1976 conducted fundamental evaluations of the form and fate of fuel nitrogen
species in fuel-rich and fuel-lean conditions. He suggested that conversion of fuel nitrogen
decomposition products to NOx could be largely suppressed if the products were held at
substoichiometric, high temperature conditions for a sufficient period. For this initial fuel rich
first stage, the high temperature accelerates the reduction of nitrogen species to molecular
nitrogen and lowers final flue gas NOx, in contrast to the lean combustion case where high
temperature promotes NOx formation.
The deep staging concept was validated in the subscale by Brown3'4 for coal firing and
England5 for oil firing. For both fuels, sub-scale results showed a hot, fuel-rich first stage with
long exposure time was very effective in suppressing fuel nitrogen conversion. Starting in 1980,
EPA supported testing to identify the best combination of first stage temperature, stoichiometry,
and residence time to minimize first stage fuel nitrogen intermediaries, and stage air injection
configurations to minimize second stage fuel nitrogen conversion and second stage thermal NOx.
A scale-up sequence was performed on combustors with heat input capacities of 20 kW (70,000
Btu/hr), 0.6 MW (2 MMBtu/hr), and 3 MW (10 MMBtu/hr).
The EPA oil burner scale-up sequence culminated in the development of a 16 MW (55
MMBtu/hr) heat input prototype combustor shown in Figure 26. This combustor was. built for
EPA by EER Corporation. It uses a first stage burner/combustor fabricated from heavy brick
refractory and designed for regenerative cooling of the outer shell by incoming combustion air.
The prototype burner/combustor was retrofit to an enhanced oil recovery (EOR) steam
generator near Bakersfield, California7. The retrofit burner-steamer configuration shown on
Figure 3, achieved NOx emissions as low as 65 ppm when firing local crude oil8. The burner
thermal response was very slow, but proved adequate to the EOR application which is base
loaded for long, sustained operational periods. The thick, hot refractory also presented special
considerations for emergency shut down or operation under low load.
5
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Figure 2. Prototype EOR burner.8
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Controls and
Feedwater oi| Gun
Pump
Burner Oil
Chamber
Radiant
Section
28.3 meters
Figure 3. EOR low-NOx burner retrofit.6
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In July 1984, the EPA low-NOx burner program was reviewed by an industrial peer
review panel preparatory to starting the present industrial boiler project. The panel viewed
the 1984 burner development as adequate for the EOR application, but in need of some
redirection for the industrial boiler market: Industrial boilers typically require much faster
start-up, shut-down, and load following response and higher turndown than EOR steamers.
Industrial boilers also have more complex control systems which must be integrated to the
burner control logic. Industrial boilers are typically in an industrial plant with stringent safety
requirements for combustion equipment. In addition, the package industrial boilers have much
higher combustion intensities and tighter fireboxes than EOR steamers, increasing the
importance of tailoring the retrofit burner flame shape to the parent boiler.
The peer review panel set the following guidelines for the industrial boiler low-NOx
burner development:
• ' Improved thermal response for start-up, shut-down, and load following
• Higher turndown
• Size reduction
• Improved safety
• Upgraded control system
In accomplishing these goals, the panel suggested that more advanced refractory materials be
considered. The conceptual design of the industrial boiler low-NOx burner was based on the
goal of using as much as possible of the earlier EPA oil burner technology while addressing the
peer review panel comments and the design goals listed in Section 1. In addition, it was clear
that satisfying the peer review panel comments would require significant changes to the design.
Yet, it was desireable to avoid further developmental testing. Accordingly, an additional goal
was added that the first full-scale prototype hardware article would be very flexible in design to
permit limited developmental testing during the field evaluation.
In satisfying these requirements with the deep staging concept, several technical trade-
offs needed to be evaluated to arrive at a practical configuration with commercial potential. The
trade-offs are generally grouped as to those affecting the first stage, precombustor section, and
those related to the second stage, boiler section. The major trade-offs are as follows:
First Stage
• Total fixed nitrogen (TFN) decay vs. residence time (size)
• TFN decay vs. precombustor temperature
• Precombustor temperature and TTN decay vs. stoichiometry
• Precombustor temperature vs regenerative cooling configurations
• Thermal response and regenerative cooling vs. refractory materials
Second Stage
• NOx vs. first stage exit temperature
• NOx vs. temperature at stage air injection
• NOx vs. stage air mixing patterns
• Carbon and CO burnout vs. second stage residence time
• Flame shaping vs. interstage throat (choke) design
• Turndown performance vs. throat design
8
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The approach taken to the conceptual design was to first focus on refractory selection.
This was done first since refractory material affects how most of the other trade-offs can be
exercised. The refractory selection also is the most important choice in satisfying the peer review
panel comments since material specification affects start-up, shut-down, and load following
thermal performance, ultimate turndown achievable, and safety requirements.
For refractory selection, a wide range of regenerable and fully insulated designs using
conventional heavy refractory, newer thin heavy refractory materials with thermal shock
resistance, and newer lightweight fiber bricks were evaluated. Several emerging refractory
materials were attractive but presented too much developmental risk for a commercial burner.
The best compromise in achieving high thermal performance with acceptable developmental risk
was a fully insulated design using lightweight fiber block bricks. This offers essentially
unconstrained thermal transient flexibility within the thermal limits of the material. The primary
design concerns with this material are the upper temperature limit of 1570°C (2850°F), the
relatively low mechanical strength, and the lack of prior experience in a turbulent, fuel rich
burner application.
The selection of the lightweight refractory material satisfies the thermal performance
goals of the industrial boiler application. The goal of reduced size was approached in two ways.
First, the NOx emission goal was critically reviewed, and the trade-offs identified.
The prior EOR work showed that very low NOx levels on the order of 65 ppm could be
achieved, but only at the price of a large, unwieldy combustor. There are major size reduction
benefits in going to a higher NOx target, as quantified in the subsequent pages.
This issue of size vs. NOx target was discussed with EPA's Office of Air Quality Planning
and Standards who had initially requested the present program. OAQPS requested the project
to improve on the commercial low NOx burner capability available when the industrial boiler
NSPS was written. When the NSPS was promulgated in December, 1987, the NOx emission
control limit with high nitrogen residual oil firing in a package boiler was on the order of 330
ppm. Developments since 1987 have not radically changed that situation for package boilers,
although much lower levels can be achieved in field erected units. The tight firebox in package
boilers severely constrains commercial NOx control techniques. In that context, OAQPS viewed
an emission target for the new burner of 100 to 125 ppm as a logical goal. Reductions below
that range would probably not be used on a nationwide basis for many years, although it could
be needed selectively in some districts.
A similar situation exists for the alternate burner use for nitrated waste cofiring. The
demand for a low NOx burner for this application was primarily to prevent NOx emissions from
exceeding typical emissions from conventional fuels rather than to seek stringent reductions
below conventional. Therefore, for both residual and waste fuels a size reduction in the burner
could be tolerated without compromising the intended market for the burner. The NOx
emission goal with residual oil was accordingly raised to 100 to 125 ppm.
The second approach to size reduction is to use sidefire air for second stage air injection
rather than injecting stage air at the throat as was done with the EOR steamer. This gives some
useful residence time in the boiler for TFN decay which would normally need to be added to the
precombustor volume. The delayed staging also allows prior cooling of the first stage products
which will reduce second stage thermal NOx. The benefits from this approach are ultimately
limited by freezing of the fixed nitrogen kinetics which gives no further NO^ reduction from
increased residence time, and by increasing CO and soot emissions if insufficient second stage
residence time is allowed.
9
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The goal of designing high flexibility into the initial prototype article was approached
in several ways. The overall combustor shell is designed from modular spools to allow changes
in residence time in the field. Stage air is ducted so it can be added through sidefire ports on
the boiler as well as either axially or radially at the throat. The burner control system is also
more flexible to accommodate parametric variation of fuel and air flows.
Satisfying the remaining design goals and settling on a configuration requires evaluating
tradeoffs in residence time, temperature, stoichiometry, and positioning of stage air ports. These
tradeoffs are summarized in the following section.
22 CONFIGURATION TRADEOFFS
22.1 Performance Data and Calculations
Extensive combustor configuration testing was done on the earlier EPA enhanced oil
recovery steamer burner development project and on an in-house EPA project.8,9 This testing
explored the effects of parametric variations of residence time, temperature, first stage fuel air
mixing, and stage air mixing on overall NOx emissions and on interstage total fixed nitrogen
concentrations. Accordingly, no additional configurational testing was done for the current boiler
design since the primary conceptual changes are to use an insulated rather than regenerable
design and to use lightweight rather than heavy brick refractory. These changes should still allow
use of much of the previous test data, although considerable interpolation and extrapolation is
needed to apply to the specific design configuration selected here. An additional change in the
industrial boiler application is to use side fire air rather than throat injection of second stage air.
This staging configuration was not generally covered in the previous EPA testing and engineering
estimates are necessary to quantify NOx emission trade offs for this addition to the design.
This section summarizes the key test data interpretations and design calculations leading
to the selection of the conceptual design configuration.
The overall concept of the deep staging EPA low-NOx burner is to promote decay of
fuel nitrogen intermediary species by the use of high temperatures in a substoichiometric
environment. Figure 4 shows kinetic calculations for simulated fuel oil flame using methane
with one percent fuel nitrogen.7 This shows the trade offs of NOx with higher temperature and
residence time. In the present design, the temperature ceiling is effectively set by refractory
material limits. The residence time benefits are traded-off against excessive space requirements
and increased costs with larger combustor sizes. The curves show the diminishing returns in NOx
reduction in going to residence times much over 300 msec. This is due to the slowing of the
reactions when the TFN concentrations are increasingly reduced.
In the current design, part of the boiler space will be used for TFN decay by introducing
stage air from side-fire air ports in the boiler rather than at the throat between the
precombustor and boiler. This will effectively increase the residence time for TFN decay without
increasing the size of the precombustor.
The use of sidefire boiler ports for injecting second stage air is also effective for
reducing second stage NOx created during the completion of combustion of the carryover fuel
from the first stage. By cooling the first stage gases prior to staging, the temperature rise is
held to a level limited only by the need to leave sufficient downstream space for carbon burnout.
10
-------
Figure 4. Chemical kinetics for TFN and NO for simulated fuel CH^ with 1% N as HCN.7
11
-------
The quantified tradeoffs on NOx, temperature and residence time are illustrated by
test data interpolations from the prior EPA test program shown on Figure 5. The data on the
left panel of the figure show the TFN concentrations at the end of the first stage for various
residence times and chamber temperatures. The correlation of NOx from conversion of TFN
is shown on the right panel. Also shown is the indicated conditions for the design point selected
for the industrial boiler precombustor low-NOx burner. At that condition, the contribution to
total NOx from the first stage is 112 ppm.
Design calculations for combustor and boiler thermal conditions and for space
requirements for second stage air injection were made for a typical California crude oil. The
oil used for design calculations had the following ultimate analysis, in percent:
Water 0.4
The equilibrium flue gas combustion products for various stoichiometric ratios are shown on
Figure 6. The corresponding adiabatic flame temperature and a predicted temperature account-
ing for heat loss are shown on Figure 7 for the fuel. The heat loss calculation accounted for
heat conduction through the combustor shell as well as radiative losses through the precom-
bustor throat into the boiler waterwalls. The corresponding data are listed on Table 1.
The effect of stage air injection on firebox temperatures was modeled with a boiler
heat transfer calculational algorithm. A 15 MW (50 MMBtu/hr) heat input capacity boiler was
used for the calculations. Typical design data for an O-type package boiler configuration was
used for the heat exchange surface orientation in the model. Figure 8 shows the predicted
temperatures and residence times for staged combustion with side-fire air. Zone I is the region
of the boiler where decay of TFN species from the first stage continues, although at a low rate.
Zone II is the second stage where combustion is completed and second stage thermal NOx is
generated. T1 is the temperature at the exit of the precombustor, T2 is the temperature at the
stage air port location, and T3 is the exit temperature of the firebox. The location of the stage
air ports was selected as 2.13 m (7 feet) from the front wall. This is the approximate distance
where the TFN decay kinetics are frozen and no further fuel nitrogen reduction accrues from
downstream placement of the ports.
The results of the temperature analysis show the residence time with sidefire staging
is longer than without sidefire air and the temperatures are lower. This is a result of the lower
velocities and higher cooling in Zone I when staging is used compared to single stage
combustion.
Sulfur
Ash
I.13
0.08
0.78
85.67
II.18
0.76
100
Nitrogen
Carbon
Hydrogen
Oxygen
Total
LHV
9855 kCal/kg (17,738 Btu/lb)
12
-------
T = 1540 - 1600°C
T = 2800 - 2900°F
TFN
msec ppm/1 msec
800 - 560 0.125
560 - 400 0.244
Figure 5. TFN data for different combustors.
13
-------
20
18
16
12
10
8
6
4
2
1
.5
1.0 1.2 1.4 1.6 1.8 2.0 2.2
Equivalence Ratio, ~
0.833 0.714 0.625 0.556 0.5 0.454
Stoichiometri c
Ratio
SR
Figure 6. Flue gas analysis for different stoichiometrics.
14
-------
Stoichiometric Ratio
Figure 7. Combustor temperatures.
15
-------
TABLE 1. ADIABATTC AND PREDICTED FLAME TEMPERATURE
Air Input
Fuel Input (25°C)
SR kcal/kg kcal/kg
Tad TKaI
0.50
1927
42.0
1157
2115
1146
2095
0.55
5420
46.2
1261
2302
1247
2277
0.60 .
5912
50.4
1362
2484
1346
2455
0.65
6405
54.7
1464
2667
1442
2628
0.75
7391
63.1
1665
3029
1635
2975
With Ai r Staging
Parameter
T,
T,
T-, Resid Time
0 (msec)
Zone I
1540^
(2800 F)
1020°C
(1870 F)
680
Zone II
1380UC
(2510 F)
100°U£
(1830 F) 620
Without Air Staging
Parameter Tj °F
T3°F
Resid. Time
(msec)
Firebox
(2800 F)
1080UC
(1970 F)
900'
Figure 8. Air staging temperature profiles: 15 MW (50 MBtu/hr) boiler.
16
-------
The NOx performance for the industrial boiler application was predicted using the
thermal model described above, together with kinetic calculations, and empirical correlations
from the prior EPA low-NOx burner program.6 Figures 9 and 10 show predicted fuel nitrogen
and NOx environments for a 15 MW (50 MMBtu/hr) boiler with the precombustor in a deep
staging mode. These results show the 112 ppm TFN from the first stage as also shown on
Figure 5. The additional residence time in Zone I of the boiler is sufficient to reduce the TFN
by 27 ppm to a level of 85 ppm before the TFN kinetics are frozen. The conversion in stage II
of this TFN carryover, combined with a 25 ppm second stage thermal NOx increment, estimated
from the temperature at staging, leads to a predicted NOx level of 85 ppm (at 3 percent 02).
This is a conservative approach to the design goal of 100 to 125 ppm. If the lower levels are
readily attainable in the prototype demonstration, removable modules, or spools, in the
combustor shell can be taken out to reduce the residence time (and combustor size) as a
tradeoff to higher NOx.
The deep staging configuration must allow sufficient residence time in the second stage
for carbon particulate and carbon monoxide burnout. A semiempirical carbon burnout
calculation was made to estimate the time-temperature conditions for sufficient burnout. These
results were compared with the time-temperature distributions resulting from the thermal
modeling discussed above for a 15 MW (50 MMBtu/hr) package boiler.
Experimental data from residual oil gasification is used to estimate the solids burden
from the first stage for a stoichiometric ratio of 0.75.10 The data on Figures 11 and 12 show a
solids burden of 3.25 percent for air atomization and 1.75 to 2.5 percent for steam atomization.
These levels should be augmented by the ash content of the oil, which is 0.08 percent for the
typical oil used in the design calculations. For these conditions, the initial soot concentration
ranges from 560 to 730 ng/J (1.3 to 1.7 lb/MBtu). For a target emission level, the utility boiler
New Source Performance Standard is 43 ng/J (0.1 lb/MBtu). For a visibility level of less than
5 Bacharach, the corresponding concentration is about 0.2 g/Nm3 (Figure 13) which corresponds
to a carbon burnout from the first stage exit of 80 to 90 percent.
A semiempirical soot burnout kinetic calculation was made for 1 micron particle
diameters which research has shown to be the most prevalent size fraction for oil soot. These
calculations showed that a residence time of about 230 msec is required to bring the initial soot
loading down to the target levels. Since a residence time of 620 msec is available for the
selected design point, sufficient space is allowed for burnout. The safety factor in residence time
will give margin to cover the case of larger particles and compensate for possible agglomeration.
Carbon monoxide burnout was also estimated from a semi-empirical kinetic expression.
The CO at the exit of the precombustor is 10.4 percent as taken from the equilibrium
calculations from Figure 6. For the thermal conditions used in the design calculations, the CO
burnout time is 1 msec. This indicates, as expected, that soot burnout is the critical factor.
Even though the design calculations indicate burnout should not be a problem with
sidefire air, the prototype design will include provision for stage air injection also at the
transition throat section from the precombustor to the boiler. This will give added flexibility
in the event combustible emission problems occur.
17
-------
Figure 9. Combustor-boiler firebox TFN decay process.
18
-------
Fuel N TFN ¦- TFN decay TFN decay2 TFN|cft and thermal NOx Total NOx
Fuel gasification SR = 0.7
Zone I
Zone II
Cooling
Fuel burn out SR = 1.25
Combustor
Boiler firebox
1% N 1000 ppm TFN—--112 ppm TFN—
—- (0 % o2)
•-85 ppm TFN
(0% o2)
60 ppm NOx +25 ppm thermal NO^*~85 ppm total NOx
(3% 02) (3% 02) (3% 02)
400 msec
680 msec
620 msec
Figure 10. NOx formation and prediction.
-------
% of fuel
3 -
2 -
1 -
1.1 1.2 1.3 1.4 1.5 1.6
Stoichiometric Ratio
Figure 11. Solid burden from gasifier with steam atomization.10
(Courtesy of the Journal of the Institute of Energy
[formerly the Journal of the Institute of Fuel])
of fuel
1.0 1.1 1.2 1.3 1.4 1.5 1.6
Stoichiometric Ratio
Figure 12. Solid burden from gasifier with air atomization.10
(Courtesy of the Journal of the Institute of Energy
[formerly the Journal of the Institute of Fuel])
20
-------
Soot concentration g/Nm^ flue gas
Figure 13. Bacharach soot concentration g/Nm3 flue gas.
222 Configuration Selection: 15 MW (50 MMBtu/hr) Thermal Input
The capacity range of the primary prototype design is 15 to 29 MW (50 to
100 MMBtu/hr). Secondary design data are also given for the original program focus in the
59 MW (200 MMBtu/hr) capacity range. The lower heat input capacity range was selected for
the primary design because the increasingly important application to waste thermal destruction
was far more likely to occur with the smaller equipment. Boiler surveys indicated that most
waste generators had boilers in the smaller capacity range, and it was relatively rare to find a
boiler as large as 59 MW (200 MMBtu/hr) at the waste generation site.
The lightweight refractory nonregenerable fully insulated precombustor shell design
was selected as discussed in Sections 2.1 and 2.3. Some design calculations were also made for
the emerging advanced concept of a thin refractory coating over a metal shell in a regenerable
design. Although this material is too risky for current use, it shows potential for effective
application upon further development. The design concept using this material is discussed in
Section 2.4.
The precombustor stoichiometric ratio was taken as 0.7 based on the NOx formation
analysis and the temperature limits of 1540°C (2800°F) for the lightweight fiber refractory
(Figure 7). The residence time for the precombustor is taken as 450 msec to allow time for oil
droplet evaporation and pyrolysis and the nitrogen decay events predicted from the formation
analysis (Figure 10).
The internal diameter of the precombustor is taken as 2.1 m (7 ft) based on the typical
size of the front wall of 15 MW (50 MMBtu/hr) boilers. This diameter is also based on an
analysis of the droplet trajectory in the atomized fuel jet to avoid wall impingement with the
lightweight refractory. The 2.1-m (7-ft) diameter should ensure that droplets evaporate before
impinging on the wall surface.
This internal diameter, together with the 450 msec residence time dictates an internal
combustor length of 2.7 m (9 ft). The precombustor will be fabricated in modules, or spools, so
that residence time can be varied in the prototype, and a similar design can be used for different
21
-------
capacity boilers. The 29 MW (100 MMBtu/hr) capacity precombustor can be fabricated by
adding an additional spool module to the 15 MW (50 MMBtu/hr) design.
The throat diameter at the transition from the precombustor to the boiler is determined
from the requirement that exit velocities are below 35 m/s (115 ft/s) to retain similar
combustion gas aerodynamics in the firebox. The exit velocities for a standard burner design is
30.5 to 43 m/s 100 to 140 ft/s. The resulting throat diameter is 0.9 m (2.9 feet) for the 15 MW
(50 MMBtu/hr) design, and 1.2 m (4 ft) for the 29 MW (100 MMBtu/hr) capacity.
223 Configuration Selection: 59 MW (200 MMBtu/hr)
The 59 MW (200 MMBtu/hr) heat input combustor design and process parameters
are similar to the 15 MW (50 MMBtu/hr) design. The total residence time of combustion
gases in the primary combustor remains at 450 msec and the temperature after combustion
and gasification of the oil is 1540 to 1556°C (2800 to 2850°F), which corresponds to the same
NOx emission design estimate of 85 ppm which was used in the primary prototype design.
The internal diameter of the chamber for the larger capacity is increased from
2.1 m (7 ft) to 2.7 m (9 ft) for two reasons. One reason is to avoid flame impingement to the
cylindrical wall with larger flame sizes. The second is to reduce the total combustor length. This
configuration is compatible with the dimensions of a package boiler of 59 MW (200 MMBtu/hr)
capacity. The internal length, 5.8 m (19 ft), corresponds to a total combustion length of 7.6
m (25 ft). For industrial boiler applications, this will require special considerations of access in
front of the boiler and will pose some difficulties for retrofit of existing units.
The exit throat diameter is 1.5 m (5 ft) which corresponds to an exit velocity of 34 m/s
(115 ft/sec). That degree of choke essentially keeps the boiler firebox flow pattern the same as
with the original burner. It also avoids flame impingement on the heat exchanger water walls
and does not reduce the flue gas residence time in the secondary firebox.
23 REFRACTORY CONCEPT FOR THE FULLY INSULATED DESIGN
The insulated lightweight refractory concept was chosen to permit the flexible duty
cycle required in an industrial boiler application. Specifically, the lightweight refractory will
allow the rapid start-up, shut-down, and load changes in package boiler applications without
destructive thermal shock as could be the case with castable or brick refractories. The material
has been used extensively in heat treating furnaces and drying ovens. There is some
developmental risk in applying this material to the precombustor internals with the highly
turbulent aerodynamics and contact with fuel rich species including reduced sulfur compounds.
Accordingly, durability endurance tests were done for a spool section of a sub-scale
precombustor fired on residual oil and gas. These results are summarized in Appendix B.
For the fully insulated precombustor design, different refractory materials are used for
the cylindrical body, for the front section with the burner throat, and the rear section with the
transition throat. The cylindrical section is fabricated with the full fiber refractory in modules
installed directly to the metal surface. The full modules are designated "Pyro-Bloc® Plus"
modules. Figure 14 illustrates the overall refractory mounting configuration. This refractory
configuration poses virtually no constraints on boiler load changes or startup transients.
22
-------
PYRO-BLOC
H MODULE
ANCHOR SYSTEM
CERAMIC TUBES
CERAMIC LINK
UNIFELT XT MODULE
Figure 14. Pyro-Bloc Plus module.
23
-------
Figure 15 shows the assembley and relative dimensions of the three layer refractory
for the cylindrical section. The components and thermal properties of the refractory sections
are as follows.
Section I is Pyro-Bloc H. It has a maximum design limit use of 1340°C (2450°F), a
recommended long term use temperature limit of 1320°C (2400°F), and a standard density of
192 kg/m3 (12 lb/ft3). The thermal conductivity of the Pyro-Bloc H is as follows:
12# Pyro-Bloc H
Temperature
Range
Thermal
Conductivi
Thermal
Conductivity
(J/m.hr.C)
c*
'F
O,
C
1. 200 94
2. 400 205
3. 600 316
4. 800 427
5. 1000 538
,6. 1200 649
7. 1400 760
8. 1600 871
9. 1800 982
10. 2000 1094
11. 2200 1205
12. 2400 1316
.4280
.4938
.5910
.7160
.8665
1.0414
1.2392
1.4578
1.6934
1.9393
2.1856
2.4179
222
256
307
371
450
540
643
756
879
1006
1134
1254
24
-------
I
7MUZZZ
o
5
I - METAL SHELL
II - PYRO-BLOC H MODULE
III - UNIFELT XT MODULE
IV-UNIKOTES COATING
Figure 15. Combustor cross section, Pyro-Bloc Pius module arrangement.
25
-------
(pN
Section II is Unifelt XT module with a maximum design temperature of 1650°C
(3000°F), a recommended long term temperature limit of 1570°C (2850°F), and a standard
density of 141 kg/m3 (9 lb/ft3). The thermal conductivity of the Unifelt XT is as follows:
Unifelt XT
Thermal
Thermal
Temperature
Conductivity
Conductivity
Range
(Btu.in/hr. frF)
(J/m.hr.K)
°F
°C
1. 200
94
.7226
375
2. 400
205
.7540
391
3. 600
316
.8098
420
4. 800
427
.8825
458
5. 1000
538
.9720
504
6. 1200
649
1.0834
562
7. 1400
760
1.2247
635
8. 1600
871
1.4045
729
9. 1800
982
1.6300
846
10. 2000
1094
1.9048
988
11. 2200
1205
2.2267
1155
12. 2400
1316
2.5852
1341
13. 2600
1427
2.9597
1535
14. 2800
1538
3.3173
1721
15. 3000
1649
3.6103
1873
Section III is Unikote™ S with a use limit of 1650°C (3000°F), and a melting point of
1879°C (3400°F).
Pyro-Bloc H is a dimensionally stable non-hygroscopic alumina silica fiber. It is formed
in standard blocks with a square cross section 0.3 m (1 ft) on a side and with thickness selected
for the application. Each block is attached to the cylindrical surface of the combustor with the
anchoring system. The anchors consist of stainless steel tubes, stainless steel brackets and nut
and bolt fasteners. The nut is welded to the cylindrical shell surface with a special tool during
the installation.
The Unifelt XT module is a Saffil™, high alumina, high purity thermally stable fiber.
Saffil fibers provide improved performance over ceramic fibers because of their microcrystalline
structure and ultra-high alumina content (over 95 percent).
The Unifelt XT veneer is attached to the Pyro-Bloc H module with ceramic links and
ceramic tubes through each module. The Unikote S coating is spayed over the module surface
after the installation. The coating serves as an initial protection of the module surface during
the start up and thermal curing of the fiber module refractory. After the fiber is cured and
solidified, any subsequent partial loss of the coating is not critical for refractory lifetime. The
coating can be periodically reapplied as a part of a regular maintenance schedule. The physical
properties of the Unikote S coating materials are:
26
-------
Unikote S
kg required per m2
3-4
Appearance
White
Lbs required per ft2,
0.6-0.8
Type
Dry powder
1/16" to 1/8" thick
Specific gravity
1.11
Installation method
Spray
Use limit, °C (°F)
1650 (3000)
Mixing water, %
40-50
Melting point, °C (°F)
1870 (3000)
Chemical Analysis (%)
Linear shrinkage, % after firing
Alumina (A1203)
88
@ 1300°C
0.3
Silica (Si02)
12
@ 1400°C
Other
—
@ 1480°C
0.5
Figure 16 shows the nomenclature for the heat transfer analysis through the cylindrical
wall which was done to confirm that temperatures are within design limits. The radiative
component of the heat transfer at the inner wall is:
Qr ,fl = 4.9 x 10"8 xe1vxfnx(TVTt1)
The convective heat transfer at the inner wall is:
Qc," = (y (T„ ¦ T, ).
Here,
£w2 = * + €w = 0.9 effective wall emissivity
2
ew = Wall emissivity = 0.8
£n = flame emissivity = 0.57
Tn = flame temperature, K
Ta, T2, T3: Wall temperature, K
ac = Convective heat transfer coefficient
= 13.6 k cal/m x h x C
The heat transfer through the wall is driven by the free convection heat transfer around the
outer wall:
T3 - Ta = T2 - T3 = Tj - T2 = Qn,r + Qfl,c
1 SI 62
Qa kl k2
27
-------
Ta Qa
11
T3
Figure 16. Heat transfer through the cylindrical wall.
An iterative solution gives for the temperatures,
T\ = 1540°C (2800°F)
T2 = 1300°C (2380°F)
T3 = 93°C (198°F)
Tfl = 1540°C (2802°F)
This analysis confirms that with a flame temperature around 1540°C (2800°F) in the
precombustor, the temperatures of the refractory materials in the insulation are below the
maximum allowable for continuous operation. The distance between the metal shell and the
anchoring system is 4.1 cm (1 5/8 in.). The temperature in that area averages 340°C (643°F).
For these conditions, the anchoring system should be made with 309 stainless steel. Also, since
the shell temperature is below 100°C (212°F), water vapor from the flue gas could condense on
the internal surface of the outer metal shell forming an acidic mixture from the sulfur and
nitrogen species in the flue gas. The extent of this effect will be small, since there is no driving
force for combustion gases to penetrate through the refractory. In any event, the inner skin of
the metal shell should be coated with a teflon coating to suppress acid attack.
28
-------
The front and rear end plates of the precombustor use a more complex structure to
accommodate the burner and combustor throat and the need for greater thermal conduction
away from the wall. The front and rear wall designs are shown on Figures 17 and 18,
respectively. The burner and combustor throats are fabricated from castable refractory which
has sufficient strength to be self supported. The castable will also be anchored by the studs
welded to the front plate and to the boiler front wall tubes. A lightweight castable refractory
is placed behind the castable plastic refractory in the front plate assembly. This provides thermal
insulation, while the castable and the studs conduct heat away from the localized hot spots on
the front face. Design calculations as well as tests at a facility not related to this program show
that the enhanced thermal conduction is necessary to avoid overtemperature of the cement
bonding the outer refractory to the inner surface. TTie properties of both front wall refractories
are listed on Tables 2 and 3.
The internal wall of the precombustor is covered by a Saffil Unifelt XT veneer module
to enhance thermal protection and obtain better thermal stress properties. The veneer module
is attached to the castable plastic refractory with a high-temperature Unistik™ cement with
physical properties as shown in Table 4. The thermal analysis for the front wall similar to the
cylindrical analysis discussed above showed the following temperature levels:
• Inner skin temperature: 1540°C (2800°F)
• Interface temperature of the veneer and castable: 1400°C (2550°F)
• Interface temperature of the castable and lightweight refractories: 1335°C (2434°F)
• Outer skin temperature: 72°C (161°F)
These temperature limits confirm that the materials will be within their permissible temperature
ranges. This is particularly critical for the cement bond which holds the Saffil veneer lining to
the castable. The temperatures in the back wall will be lower since the heat removal from the
boiler tubes will reduce temperatures. The thermal analysis was not repeated for the back wall.
The nonregenerable fully insulated design discussed here appears to allow reliable
operational temperatures, acceptable outside temperatures which will require only a protective
grid, and will permit combustor operation without any limitations on the start up rate and
capacity change under transient conditions.
2.4 REFRACTORY CONCEPT FOR THE REGENERABLE DESIGN
The regenerable concept is considered as a potential future application which needs
development and demonstration before it can be credibly used for burner fabrication. The
technology is under development for gas turbine cans and as a high temperature corrosion
protective barrier in numerous applications. The technology employed is to use a zirconium
silicate substrate bonded to a single compliant layer of sintered metal fibers. The inner layer
compensates for thermal expansion and permits the ceramic to reconfigure to reduce stresses.
The fiber metal layer has a modulus of elasticity lower than the ceramic or typical metals used
in fabrication. It also has a high elastic limit of approximately 2 percent elongation. The
sintered pad is attached to a solid metal base using conventional alloys. The ceramic can be
deposited on the fiber pad by direct plasma spraying of a bond coat and ceramic. The low
elasticity modulus values of the pad induce low stresses in the ceramic layer and allows the metal
shell to move independently of the ceramic layer in a high temperature environment with high
temperature gradients.
29
-------
0.56 m
Studs
steel 309
1.3 cm diameter
58.4 cm length
Lightweight
castable
refractory
Castable
plastic
Pyro-Bloc Plus module
Figure 17. Combustor front end plate and wall assembly.
-------
0.31 m
Studs steel 309
1.3 cm diameter
5.7 cm length
KAO-Plus C85
Studs steel 309
1.3 cm diameter
1.9 cm length
o
us C85
ness
co
§
co
<
tic refractory.
Combustor
throat
Figure 18. Combustor rear wall throat design.
31
-------
TABLE 2. KAO-PLUS C85 CASTING PLASTIC MONOLITH-AVERAGE PROPERTIES
Water addition requirements, wt.%
Recommended use limit °C (°F)
Lbs. required to place one ft:3.
kg required to place one nr*
Specific gravity,
fired @ 980°C (1,800°F)
Condition
Cold Crushing
Strength
9.5
1760 (3,200)
160
2600
2.5
Permanent Linear
Dried 24 Hrs. @ 104°C (220°F)
900
131
-0.1
Fired 5 Hrs. @ 816°C (1,500°F)
2,000
290
-0.2
Fired 5 Hrs. @ 1094°C (2,000°F)
4,000
580
-0.2
Fired 5 Hrs. @ 1700°C (3,100°F)
5,500
798
+ 0.4
Chemical analysis, % fired basis
Alumina
ai2o5
81.2
Silica
Si02
13.9
Ferric oxide
Fe2°5
1.6
Titania
Ti02
2.2
Alkalies, as
Na20
0.5
Thermal conductivity
Btu in./ft2
hr °F J/m hr K
Mean temperature @ 260°C (500°F)
7.8
4047
@ 540°C (1000°F)
7.9
4098
@ 816°C (1500°F)
7.9
4098
@ 1094°C (2000°F)
8.3
4306
32
-------
TABLE 3. LIGHTWEIGHT CASTABLE PHYSICAL PROPERTIES
Maximum service
Temperature
ASTM Class C-401
Dry castable required
Water required for
Pouring (approximate)
Bulk density after
Drying at 230°F (110°C)
Modulus of rupture after
Drying at 230°F (110°C)
Heating at 1.000T (540°C)
Heating at 1,500°F (816°C)
Heating at 2,700°F (1,480°C)
Cold crushing strength after
Drying at 230°F (110°C)
Heating at 1,000°F (540°C)
Heating at 1,500°F (816°C)
Heating at 2,700°F (1,480°C)
Heating at 900°F(1595°C)
Reheat test, permanent
Linear change, percent after
Drying at 230°F (110°C)
Heating at 1,000°F (540°C)
Heating at 1,500°F (816°C)
Heating at 2,900°F (1,590°C)
Thermal conductivity
500°F (400°C)
1,000°F (600°C)
1,500°F (800°C)
2,000°F (1,000°C)
Chemical analysis
(Approximate %)
(Calcined Basis)
Silica (Si02)
Alumina (Al2Oj)
Titania (TiO,)
Iron Oxide (Fe2Oj)
Lime (CaO)
Magnesia (MgO)
Alkalies
(Na20 + K2 + Li20)
3,000°F 1649°C
88 lbs/ft3 1412 kg/m3
3 1/4 to 3 1/2 gal/100 lbs 300 g/kg
92 lbs/ft3 1476 kg/m3
Lbs/in.2 kPa
150 to 250 22 to 36
50 to 100 7.3 to 15
100 to 150 15 to 22
700 to 1300 102 to 189
Lbs/in.2 kPa
500 to 1000 73 to 145
400 to 600 58 to 87
500 to 770 73 to 112
2100 to 2600 305 to 377
2100 to 2800 305 to 406
Negligible
0.0 to -0.2
0.0 to -0.2
-1.0 to +1.5
Btu/hr ft2 °F/in J/m hr K
3.48 1805
3.61 1873
3.87 2008
4.20 2179
35.0
57.3
1.7
1.1
4.1
0.1
0.7
33
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TABLE 4. UNISTIK CEMENT
Physical properties:
Unistik A
Appearance
Gray
Type
Wet
Airset
Use limit, °C (°F)
1,540 (2,800)
w/module
kg (lbs) required per
1.4-1.8
module
(3-4)
For use with
Plastic
dense
castable
firebrick
Chemical analysis (%)
Unistik A
Alumina (A12Oj)
37.0
Silica (SiOj)
57.0
Iron oxide (Fe2Oj)
1.0
Titania (Ti02)
1.0
Alkalies (Na20 + K20)
3.0.
Trace inorganics
1.0
A conceptual design of the regenerable precombustor design using the zirconia coating
is shown on Figure 19. The precombustor is a double shell design with an annular space for
cooling air which is also the combustion air for the primary burner. The inner shell, which is
also the combustor wall is covered with the composite layer. The metal fiber material is also a
thermal barrier with significantly lower thermal conductivity. Nevertheless, extensive cooling is
required to maintain acceptable temperatures at the combustor inner shell.
A thermal analysis of the regenerable design was done to determine if the temperatures
were within the design limits. Figure 20 shows the respective heat fluxes. A heat balance.shows
that for a regenerative air velocity of 3 m/s (9.8 ft/s), and a coating thickness of 1.2 mm (0.3 in),
the metal temperature is 200°C (391°F). The results show that the regenerable design is practical
from a thermal performance standpoint. The primary development which is needed is in the
coating technology as applied to larger sizes. Currently, only smaller gas turbine size
applications have been made.
34
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Zr ceramic coating
0.06 in. (1.524 mm)
Bond coat 0.003 in.
Fiber metal
strain isolator
0.06 in
Cr Ni Alloy v
1/2 in . (12. 7 rmn7
CNJ
^r
9
CO
CO
<
/ 2600°F (1427°C)
/ 1300°F (932°C)
1200°F (649°C)
/ 392°F (200°C)
Figure 19. Regenerative Iow-NOx combustor design: 59 1VTVV (200 MMBtu/hr)
capacity.
-------
Figure 20. Heat transfer scheme regenerative design.
36
-------
SECTION 3
COMBUSTOR AND RETROFIT DESIGN
This section presents the low-NOx precombustor design and boiler retrofit based on the
concepts raised in Section 2. This design is intended to be as adaptable as practical to the
general class of industrial package boilers in the 15 to 29 MW (50 to 100 MMBtu/hr) thermal
input capacity range. Despite the adaptability, there are two boiler interfaces which will be
specific to the boiler which is being retrofit. The integration of the control system to the existing
boiler and plant controls will also have site-specific aspects. Within that context, the design
presented here is a detailed generic design.
The parameters that ultimately determine the equipment configuration are the following
with associated ranges considered:
• Capacity 15 MW (50 MMBtu/hr) (nominal) to 59 MW (200 MMBtu/hr) thermal
input
• Fuel - gas, No. 2 fuel oil, No. 6 fuel oil, waste fuels
• Maximum permissible emission levels i.e., NOx
• Site interface requirements - boiler size and type, site layout and integration
requirements
The capacity of the boiler will influence the size of the burner and associated fuel train
whereas the control system would be identical in all cases with the exception of different
customer-required safety system interlocks. Capacity of the boiler influences the residence time
in the first stage precombustor which has been addressed in the design by providing modular
spool pieces in the combustion section.
The different fuels will impact the requirement of residence time in the precombustor
and minimum inside diameter of the combustion section. Flame impingement on the walls was
considered in selecting the final configuration. Since the design utilizes a modular approach,
customization of each combustor is not going to significantly impact cost. The size and cost of
the equipment will always be produced on order rather than to inventory. Suitable components
may be stocked and combined on order. This is the typical operation mode of large equipment
vendors. The automobile industry too has adopted "just in time" inventory management to
reduce financing cost and to prevent the obsolescence of inventories items by advances in the
technology.
Site requirements will dictate the maximum size of the first stage precombustor and how
equipment may be arranged in the equipment halls. Each installation is likely to have its own
unique individual requirements that must be addressed on a case-by-case basis. The equipment
modules may be the same, but how they are arranged is likely to be customized as the real estate
allows.
37
-------
Figure 21 shows the process diagram for a nominal 15 MW (50 MMBtu/hr) boiler with
low-NOx burner system in place and the associated process flows. This combustor is shown firing
No. 6 fuel oil and high nitrogen waste. Figure 22 shows a cross-section of the first stage
precombustor and some details of the internal configuration. Full design drawings are supplied
in Appendix C.
The low-NOx burner system can be divided into several main subsystems as follows:
• Burner
• First stage precombustor
• Fuel and combustion air valve train
• Auxiliary equipment
• Control and data acquisition system
Examination of the various classes of subsystems reveals that some fall into the category
of conventional equipment already utilized on combustion equipment. The primary components
of interest are the burner, first stage precombustor, and the control and data acquisition system.
Of additional interest is which modifications need to be made to existing boilers in a retrofit
operation to install a low-NOx burner system. The subsystems of particular interest are
discussed in greater detail in the following sections.
An important consideration when evaluating the cost of the low-NOx burner system
compared to other systems is the incremental cost of this type of control system. It should be
expected that the cost of burner, fuel and combustion air valve train, and auxiliary equipment
is virtually identical to that of a standard boiler installation. Increased costs are due to the first
stage precombustor, modifications to existing boiler front walls, the installation of additional
sidefire staged air ports, and an increase in the cost of the control system and valve train due
to increased control logic requirements.
Real estate requirements may be important if buildings have to be enlarged or no space
is available. Whether these costs should be included is a question that is likely to be site
specific. It is possible to orient the precombustor vertically with a suitably designed elbow at the
transition section to the boiler. This configuration could be used at a site with limited horizontal
front wall access.
3.1 BURNER
The burner for this application is of standard design. NOx control is achieved by
controlling the air/fuel ratio in the first stage precombustor and the subsequent injection of air
at the throat or in the main combustion chamber. A register burner with adjustable louver
blades is specified. This type of burner offers capabilities for flame shaping and provides high
turn-down ratios. Fuel atomizers are installed as the case may require for the various fuels and
wastes. Large variations in viscosities require the adjustment of nozzle sizes as well as
adjustment in atomizing air or steam pressure. Figures 23 and 24 show typical burner and
atomizer configurations.
32 FIRST STAGE PRECOMBUSTOR DETAIL
The ideal installation of the precombustor will provide for access as typically found on
a shell and tube heat exchanger. The entire structure is mounted on wheels to allow for thermal
expansion along its length and also for inspection access. The valve train and burner controls
38
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100' Load
Stream #
1
2
3
4
5
6
7
8
9
10
11
12
13
Fluid
AIR
AIR
AIR
AIR
#6
#6
#6
STEAM
WASTE
WASTE
WASTE
NG
FLUE
•
1
1
1
100
100
100
100
100
100
100
60
0.1
Tnom^
70
70
70
70
220
220
220
220
220
220
220
70
400
Mnom(KIPS/HR)
42
7
7
28
3
2
5
0.35
1.25
0.8
0.45
0.05
45
PMAX
150
150
150
150
250
250
250
250
250
250
250
110
500
MVtAX^K,PS/HR)
45
8
8
30
4
3
6
0.5
3
3.5
3.5
0.1
50
Figure 21a. Process diagram — English units.
-------
100/. Load
Low-NO Burner Process Flow
Stream #
1
2
3
4
5
6
7
8
9
10
11
12
13
Fluid
AIR
AIR
AIR
AIR
#6
#6
#6
STEAM
WASTE
WASTE
WASTE
NG
FLUE
PNOM±^kPa^
.15
.15
.15
.15
14.5
14.5
14.5
14.5
14.5
14.5
14.5
8.7
0.01
Tnom^c)
21
21
21
21
105
105
105
105
105
105
105
21
205
MNOM^TonneS/,hr^
19.1
3.2
3.2
12.7
1.4
0.9
2.3
0.16
0.6
0.4
0.2
0.02
20.5
PMAx(kPa)
.15
.15
.15
.15
21.8
21.8
21.8
21.8
21.8
21.8
21.8
8.7
0.01
tmax (°c)
66
66
66
66
121
121
121
121
121
121
121
44
260
MMAX^TonneS//hr^
20.5
3.6
3.6
13.6
1.8
1.4
2.7
0.23
1.4
1.6
1.6
0.05
23
Figure 21b. Process diagram — S.I. units.
-------
BURNER END
SECTION
CENTRAL SPOOL
SECTION
BOILER AND END
THROAT SECTION
Figure 22. The combustnr section.
-------
Coen Register Burner
The Coen register is
designed with adjust-
able louver blades to
provide optimum
combustion effi-
ciency coupled with
wide turndown ability.
With Coen's proven
design and rugged
construction the
register burner will
provide years of
trouble free
service.
• Available with integral scroll for low BTU. gas or
coal requirements.
• Engineered to meet low NOx emission standards for each
application as required.
• Available as integral part of single burner package or for
multiple burner applications.
• Available with ring type or multiple spud type gas burner
elements.
Figure 23. Example register burner.
(Courtesy of the Coen Company)
42
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Coen Atomizers
Coen offers three types of atomizers, each in several sizes,
to handle fuel oils or liquid wastes:
Coen MV Atomizer
• Inside mix steam/liquid atomizer.
• Four sizes available for flow rates up to 35 gpm with steam
pressures of 100 to 200 psig, each with wide range
capability.
• Atomizes liquids from low viscosity up to 500 SSU.
• Capable of producing special asymmetrical spray
patterns.
Coen MA Atomizer
• Low pressure inside mix air/liquid atomizer.
• Four sizes available for flow rates up to 25 gpm, with air
pressures from 5 to 15 psig, each with wide range capability.
• Preferred method of atomization when steam is not available.
• Ideal for corrosive or low flash point liquids, up to 300 SSU.
• Capable of producing special asymmetrical spray patterns.
Coen SNC Atomizer
• Outside mix steam/liquid atomizer.
• Two sizes available for flow rates up to 12 gpm with
atomizing steam at 150 psig.
• Atomizes high viscosity sludges or liquids with large
particles, up to 'A* diameter.
Figure 24.
Example atomizer.
(Courtesy of the Coen Company)
43
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are mounted on a separate rack or structure to the side of the precombustor rather than on
the back or near the burner end section. With this configuration arrangement, changes in the
length (residence time) for low-NOx control can be easily accommodated. Typically, an
installation will only be as long as is needed to achieve the desired emission control
requirements.
The precombustor section consists of several main modules that can be combined to
provide optimum operation of the system for low-NOx emissions. The top assembly drawing on
Figure 22 shows a section of the three main components: the burner end section, the central
spool section and the boiler end and throat section. Each component has been designed to
provide the needed prototype flexibility to adjust operating conditions for optimum operation.
The burner end section will be configured to accommodate the burner size requirements
while providing a standard bolt interface to the central section spool pieces. The maximum
surface temperature permissible is 1540°C (2800°F). The length of the combustor can be
adjusted by installation of different one-piece center sections or by the combination of various
standard center sections. It is desirable to minimize the number of seams and for this reason
it is recommended to minimize the number of center sections. Regenerative designs had initially
been considered; however, the complexity of joints and parts in general would have resulted in
significantly higher costs and much lower configuration flexibility for the refractory chosen.
The central section has been designed to be provided in several basic lengths. They are
0.91, 2.5, and 2.9 m (36,100 and 116 in.). Other section lengths could be provided if needed.
The configuration of the lightweight insulation material provides good thermal response
and compatibility with boiler requirements in terms of response time. The insulation system will
provide for quick start-up (15 min.), easy installation, and has been demonstrated on industrial
furnaces. Sections 2.2 and 2.3 summarize the maximum use temperatures, the long term use
limits and the method by which the insulation material is held in place with anchoring ceramic
tubes. The burner end section utilizes a combination of Pyro-Bloc H and lightweight castable
refractory. The combination of these materials will provide the needed abrasion resistance in
the areas where it is needed. Also, the castable base material will provide higher heat
conduction to keep the Pyro-Bloc temperatures within design limits.
The expected operating temperature of the inside wall can be controlled well by
controlling the stoichiometric ratio in the precombustor. Figure 7 shows the relationship of
combustion temperature with stoichiometric ratio. Control is addressed in Section 3.4.
3 J BOILER INTERFACE
The precombustor is joined to the boiler via the boiler end section. The boiler end
section serves a number of functions. It serves as a bolting arrangement to fasten the
precombustor spool pieces to the boiler, restrict the precombustor flow and allow for the
addition of secondary air either axially or tangentially. The large diameter throat is necessary
to lower the gas to typical boiler gas velocities of 36.6 m/s (120 ft/sec) in the region.
The throat is made from lightweight refractory to improve the abrasion resistance.
Sharp corners have been avoided to reduce the chance of fracture. At the boiler interface, tubes
have been formed around the throat to help cool the gas and maintain temperatures to the
maximum acceptable levels at the air injection plenum which is fabricated from stainless steel.
The injection tubes will be allowed to burn out if metal service temperatures are exceeded
without detriment to their function. Future product designs may see some reduction in the
44
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complexity of the throat design if it is found that the all stage air can be injected at the sidefire
air ports. Details of the boiler end section are shown in Appendix C. Final air duct routing will
depend on the site specifications when known.
3.4 CONTROL SYSTEM AND DATA ACQUISITION
3.4.1 Introduction
The normal product development path typically results in the design and construction
of the product at various stages of maturity. Only in the simplest cases is a final product
reached in the first design cycle. The design of the control system for the low-NOx burner is no
exception. It does not fall into the "simple" category and it is prudent to provide for initial
control flexibility in the prototype that will allow for the tuning of control loops and easy
modification of the control strategy after initial operation when the true characteristics of the
combustor and precombustion chamber become known. A trade-off is usually made between
analytical and empirical evaluation to determine the expected performance. Actual operation,
however, always determines whether the analysis conducted was correct or not. The "extra"
initial control flexibility provided increases the cost of the first control system, but also insures
that all objectives can be met at minimum system development cost.
It should be expected that the final control system configuration can be implemented
in a very cost effective way utilizing state of the art microprocessor technology and
programmable logic controllers.
The initial prototype system will also have a greater need for more data aquisition than
will be required of the product version to permit the proper evaluation of system performance.
Optimization of cost can only occur, when all the operating parameters are fully understood.
For this product this leads to a disproportinately high initial control and data aquisition cost in
the prototype. This should be viewed as an intermediate step toward the final system
configuration which would be cost effective.
At least three control system suppliers presently offer competitive, easily configurable
distributed microprocessor based control systems. These microprocessor systems are capable
of automating entire production processes provided they are equipped with the appropriate
input-output modules and may be seen as an overkill for the application. Experience with
alternative lower cost IBM-PC based control systems, however, has shown that the cost of
programming is very substantial indeed, often exceeding the cost of the initial system many
times. The overall cost of the control system must be considered to come to a fair conclusion
whether it is cost effective. Due to the flexibility that has been built into these systems the
advantages of the microprocessor system as development tools for the prototype are
overwhelming compared to a simple PC system. Data aquisition can also be accomplished by
the microprocessor systems and various reports printed as required. Data can also be
downloaded to other computer facilities for further evaluation and processing. Some complete
systems offer I/O modules at IBM-PC competitive prices making the integrated control system
and data aquisition option very attractive.
3.42 Control Strategy
The burner management system consists of an integrated set of control strategies that
address the need for safety, equipment operating limitations, optimum operating conditions, and
regulatory requirements.
45
-------
• The burner management system will incorporate a primary flame safeguard relay
to provide the standard and typical safety interlocks addressing the need for purge
cycles, flame sensing, and start-up.
• An integrated multitasking control system will provide system interlocks and PID
controls to maintain appropriate air/fuel ratios and heat rates for low-NOx and
soot emissions and regulate capacity requirements.
• Additional control loops are utilized to monitor precombustor operating conditions
such as temperature, staging air, and waste feed permissive signals.
• Operating constants for stage air, waste feed percent, precombustor temperature
set points or gradients, and minimum waste feed combustor temperature can be
changed in the prototype easily by the operator. An evaluation needs to be made
upon final system configuration determination what parameters should be fixed
and which should be changeable by operators.
The control system configuration is shown in schematic form in the process and control
instrumentation diagram drawing number 8023-001 shown in Appendix C. A typical fuel train
reflecting a similar degree of complexity is shown in Figure 25. This diagram reflects the
capability to fire either No. 2 or No. 6 fuel oil in conjunction with waste fuels. This system is
set up to allow air and fuel ratios to be adjusted completely independently a feature that may
not be required of a product once the exact operating characteristics are known. The functions
of all the control loops will be discussed in detail in the following paragraphs. Future controls
may also incorporate the use of "ganged" valves to reduce costs of operating control channels and
valve operators. It should be expected that the control system for the low-NOx burner will be
more complex than that of a conventional burner of similar size and capacity due to the complex
operating requirements during start-up and the requirement to closely monitor and adjust the
fuel/air ratios to maintain tight temperature control in the precombustor section.
There are a number of operating constraints that must be satisfied to meet the
objectives of low-NOx, achieve the destruction of fired waste materials, and at the same time also
satisfy other regulatory requirements. Parameters that must be observed in particular are:
• Up to a maximum of 50 percent total heat input may be derived from waste fuels.
• Waste fuel firing must be discontinued if the temperature in the precombustor
drops below a predefined value no longer insuring the destruction of waste
components.
• Waste firing is not permitted at a load below 25 percent of full capacity.
• The wall temperature in the precombustor may not exceed 1540°C (2800°F)
• During normal operation the air/fuel stoichiometric ratio must be maintained in
the range of 0.7 to 0.9 for low thermal NOx formation in the precombustor. Upon
leaving the precombustor, while the remaining air is added, temperatures must be
reduced quickly to prevent formation of second stage thermal NOx but still ensure
soot burnout. Proper mixing of the additional air must be assured in the
precombustor/main combustor nozzle and/or at the sidefire air staging nozzles.
The critical relationships that should be observed to minimize NOx are summarized in
Section 2.2. For this combustion design, these conditions will also provide an environment highly
conducive to good waste destruction. The time-temperature conditions in the low-NOx mode
are far superior to the thermal destruction environment in a typical boiler. A typical boiler
cofiring waste has been shown to provide a waste destruction efficiency averaging 99.998 percent.
The present design should improve on this efficiency. In addition, and very significantly, the
current design should also emit much lower levels of products of incomplete combustion (PICS).
46
-------
-------
The Section 2.2 material showed that if the stoichiometric ratio is maintained around
0.7, NOx emissions will be minimized and the refractory temperature limits will be maintained.
Upon the addition of the remaining second stage air it is essential to reduce the temperature
quickly to maintain the low emission levels desired.
The relationship of NOx emissions to first-stage residence time shows that longer
residence times result in lower emissions rates. Since the combustor volume is fixed, lower firing
rates should result in lower ppm emission rates. For this type of staged combustion burner, the
levels of NOx emissions are virtually unaffected by the amount of fuel nitrogen which leads to
the conclusion that this type of burner is ideally suited for the combustion of high nitrogen waste
fuels. All of the above considerations are integrated into the control system strategy to minimize
emissions during all phases of operation including start-up, normal operation, load changes, shut-
down, emergency shut-down, and during fuel switching.
The process and instrumentation diagram reflects five primary process streams. They
are natural gas, No. 2 fuel oil, No. 6 fuel oil, waste fuels, and air. It is envisioned that the
combustor will be operated primarily with a combination of No. 6 fuel oil and waste fuels and
that No. 2 fuel oil and gas would only be used during the start-up phase of operation. This does
not mean that the combustor cannot be operated on other fuels but that the primary benefit
would be derived in terms of emission reductions from operation with these fuels.
The operation sequence is outlined following explaining the normal start-up, operation
and shut-down of the facility in principle. Detailed control loops must be defined in a control
specification document. To help understand the procedure it is helpful to know that ratio
control valves are employed to adjust the fuel air ratios for the various fuels and that excess air
is introduced via air by-pass valves.
3.43 Start-up, Operation and Shut-down Control Sequence
1. The start-up sequence may begin when the system interlocks show no alarm
condition that would prevent operation of the burner. Status of these interlocks
allows the flame safeguard relay to permit the start of the start-up sequence after
receipt of the start sequence.
2. Valves and other control elements are properly set by the control system to
perform and monitor a purge cycle. Upon completion of the number of volume
changes in the combustor, the flame safety relay will open the pilot air and gas
valve and light the pilot light.
3. Upon successful ignition verified by the flame sensor, the flame safeguard relay
will permit the operation of the main No. 2 fuel and air valve. Flame failure
detection will result in another purge cycle.
4. The main and bypass air valves and No. 2 fuel valve are opened and firing
proceeds at approximately 3 percent excess air in the precombustor for warm-up.
The main air flow maintains the fuel flow at .7 to .9 stoichiometric ratio via the
ratio control valve while additional air is introduced via the air bypass. The fuel
firing rate is determined by the maximum heating rate previously programmed into
the control sequence.
5. Two additional control loops are particularly important at this time monitoring
excess air conditions and the precombustor temperature. The excess air monitor
48
-------
generates a signal that is compared to the set point and the excess air control loop
adjusts the excess air as required. The precombustor temperature is monitored by
the temperature control loop that also interacts with the fuel firing rate controller.
At a predetermined temperature, No. 2 fuel firing may be switched to No. 6 fuel
oil by switching the fuel main solenoids and also switching the fuel ratio sensing
three-way valves.
6. As the temperature in the precombustor approaches the maximum operating
temperature, bypass air to the precombustor is reduced and introduced as second-
stage air in the main orifice area or into the main combustor as the control
strategy requires. Lower stoichiometric ratios reduce the maximum combustion
temperature while also reducing NOx emissions.
7. Waste fuel firing can be implemented anytime the combustor is operating at
25 percent or higher capacity and the minimum combustion temperature for waste
firing is attained in the precombustor. Waste firing is initiated by opening the
appropriate waste fuel air control valve and simultaneously closing the main fuel
air valve. Proportional main fuel and waste fuel firing is maintained by the
proportional control valves.
8. Load following is accomplished by the main air flow control valve which controls
the airflow for main fuel, waste fuel and stage air. Reduced air flow due to
throttling by this valve results in lower pressure drops across the ratio control valve
orifices causing proportional reductions in main and waste fuel flow and
proportional reduction in stage air flow. The important feature to observe is that
the relative positions of valves are not changed. The main to waste fuel ratios are
maintained. An additional capability provided by this control system and the piping
arrangement is the capability to fire waste at a fixed firing rate while the main fuel
is modulated to provide load following. This is the firing mode often used by
operators, because the control capabilities of the existing systems can not provide
for the previously discussed methodology. The draw-back of the latter system is
that the full waste destruction capability of the system is not utilized.
9. Normal system shutdown is accomplished by reducing main air flow which in turn
causes waste fuel firing to be stopped when the 25 percent capacity level is
breached. As capacity is decreased further, the temperature in the precombustor
will be lowered resulting in stage air reduction and stoichiometric firing in the
precombustor until stage air is reduced to zero. Further firing rate reduction will
result in cooling of the precombustor at the predetermined cooling rate resulting
in the eventual shut-down of fuel flow. Cooling of the facility may continue by
air circulation or as desired.
10. Emergency shut-down is accomplished by closing all fuel valves simultaneously but
maintaining air circulation. Emergency shut-down would most likely be triggered
by the flame safety relay due to loss of flame or some other system malfunction
that would cause the flame safety relay to act.
3.4.4 Data Acquisition
The control system will also be able to serve as an integrated data aquisition system.
Many of the input control channels may double as data aquisition channels. Since formatting
and time sequences can be fully integrated, no compromise in reliability will result.
49
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3.4.5 Control System Specification
A specification of the control system meeting the needs of the prototype low-NOx
combustor follows. A detailed listing of the required input/output channels is also presented
in Table 5, not accounting for possible channels required for the boiler or other system
requirements.
3.4.6 Control System Requirements
General
The control system to be supplied shall consist of a complete process automation system
that includes all the control functions (software) and hardware to permit automation of the test
operation of the low NOx combustion burner system. The system shall have sequential, logic,
loop and multivariable control functions completely integrated. Each shall be capable of
interacting with the others. Sequential control shall be able to turn loops on and off, open or
close cascades, and set alarm limits or setpoints. Logic shall be able to change the sequential
operation based on process changes or interlocks, or shut the process down upon emergency
conditions. Multivariable control shall set continuous loop set-points or output directly to
actuators. All values shall be directly accessible by all automation functions.
The control system shall be complete within its own operating system software, so that
the test engineer can configure the control strategies without writing any computer code. The
control system should employ enhanced concepts to expedite procedure strategy definitions that
are presently available in Computer Aided Design (CAD) systems. Since the low-NOx burner
system is a prototype and would be used to optimize operation and define a final product, a
system offering user-friendly approaches is important. Therefore, the control system design
should allow for minimum configuration or set-up time and maximum operation or test time.
Current information indicates that CAD-type versus high level language type set-up systems offer
the most efficient use of available test time.
The control system should be designed to allow for ease of start-up and commissioning.
It is desired that the system be designed to minimize the possibility of human error in
configuration or set-up; i.e., avoid reuse of already named inputs, multiple loop calculations
trying to control one common control output, use of unrelated variables in a control state, etc..
After various test and operational procedures have been defined, accepted, and implemented,
the system will need to be operated by non-engineering oriented, as well as engineering oriented
personnel.
The preferred concept of the control system would consist of (1) one touch screen color
graphics display, multiple remotely located process controllers, multiple varied I/O modules
connected to their associated controllers, and controller and I/O module uninterruptible power
supply capability. System components shall be designed to reduce installation, replacement, and
maintenance costs.
Report Generation
The control system, being used as an optimization tool for the prototype low-NOx
burner system, must be able to generate various summary reports and allow the developer to
efficiently evaluate his or her procedures. A system automatically generating its own reports
would be preferred. A system that categorizes its reports to I/O, controllers, work station, and
process variables has significant advantages. Examples of suggested type reports are as follows:
50
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TABLE 5. SUMMARY OF INPUT/OUTPUT SIGNALS FOR LOW-NOx BURNER SYSTEM
'AG NAME
DESCRIPTI ON
FLUID
SIGNAL
TYPE
F'SL- 211
LOW GAS PRESSURE
GAS
CONTACT
I
PSL- 174
LOW #2 OIL PRESSURE
#2 OIL
CONTACT
I
F'SL- 173
LOW *6 OIL FRESSURE
#6 OIL
CONTACT
I
PSL- 172
LOW WASTE PRESSURE
WASTE
CONTACT
I
V- 203
GAS SHUT-OFF
GAS
115
VAC
0
V- 205
GAS SHUT—OFF
GAS
115
VAC
0
V- 204
GAS VENT
GAS
115
VAC
0
V- 203
PILOT AIR SHUT-OFF
AIR
1 15
VAC
0
HS- 304
#2 PUMP START/STOP
#2 OIL
1 15
VAC
0
V- 153
*2 FUEL OIL SHUT-OFF
#2 OIL
115
V wC
0
HS- 303
#6 PUMP ST ART/STOP
#6 OIL
115
VAC
0
V- 165
SIGNAL DIVERTER VALVE
A IF:
1 15
VAC
0
V— 1 6o
SIGNAL DIVERTER VALVE
AIR
1 15
VAC
0
V- 157
#6 FUEL OIL SHUT-OFF
#6 OIL
115
VAC
0
HS— 302
WASTE PUMP START/STOP
WASTE
115
VAC
0
V- 167
WASTE SHUT-OFF
WASTE
1 15
VAC
Q
HS- 3'.) 1
BLOWER START/STOP
AIR
115
VAC
0
FCV- 102
MAIN AIR CONTROL FORWARD
AIR
115
VAC
0
FCV- 102
MAIN AIR CONTROL REVERSE
AIR
1 15
VhC
0
FCV- 109
BYPASS PRE-COMB FORW
AIR
115
VAC
Q
FCV- i <:¦ MA
I
PT- BP
BOILER PRESSURE
STEAM
4-2
0 MA
I
DPT- 107
PRE-COMB MAIN FUEL AIR
AIR
4-2
"J MA
I
DPT- 108
PRE-COMB BY-PASS AIR FLOW
AIR
4-2
0 MA
I
DPT— 126
PRE-COMB WASTE AIR FLOW
AIR
4-2
0 MA
I
PT- 128
PLENUM AIR PRESSURE
AIR
4-2
0 MA
I
DPT- 129
STAGING AIR I FLOW RATE
AIR
4-2
:> MA
I
DPT- 131
STAGING AIR II FLOW RATE
AIR
4-2
0 MA
I
AIT- ST
EXCESS OXYGEN
FLUE
4-2
0 MA
I
TE- 103
MAIN AIR TEMPERATURE
AIR
TC
I
TE- 127
PLENUM AIR TEMPERATURE
AIR
TC
I
TE-
COMBUSTOR TEMPERATURE I
FLUE
TC
I
TE-
COMBUSTOR TEMPERATURE II
FLUE
TC
I
TE-
COMBUSTOR TEMPERATURE III
FLUE
TC
I
TE-
COMBUSTOR TEMPERATURE IV
FLUE
TC
I
TE-
COMBUSTOR TEMPERATURE V
FLUE
TC
I
TE-
COMBUSTOR TEMPERATURE VI
FLUE
TC
I
51
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(1) batch report, (2) control state history report, (3) trend reports, (4) alarm history report, (5)
operator action report, (6) timed shift log reports, (7) system self-health reports, (8) emergency
shutdown report, (9) start and end batch reports, (10) procedures executed report, and (11)
engineer/operator user name report.
Work Station
The work station shall be the interface between the engineer or operator to the process
or processes. The work station shall be usable by the process engineer developing a procedure,
as well as an operator presently controlling a process or processes. The work station shall be
industrially rugged. System operating software, main computer hardware, color graphics touch
screen CRT, power supply, and ventilation equipment shall be housed in the work station
cabinet. Additionally, communications equipment that allows the work station to communicate
with multiple remote process controllers or other computers should be housed in this cabinet.
The color graphics touch screen CRT is the actual operator interface with the process
or processes. The color graphics screen shall provide for multiple pictorial representations of
each process being controlled. A master color code scheme shall be employed to indicate alarm
conditions. Additionally, the CRT shall have color coded indicators (one for each controller)
of multiple process conditions. The CRT screen shall have the capability to be used for real-
time trending of measured or calculated values over an operator selected history time window.
The touch screen process indicator areas shall be able to call up preselected displays for
each process controller whenever the operator touches a specific indicator area. Once viewing
the selected display, the operator shall be able to touch selected areas of these displays to
advance the CRT to a more detailed diagram of the process. The system shall offer the
operator total ability to develop unique process diagrams as the test engineer is defining his
control strategies.
The work station shall be the device the test engineer uses to define the process control
strategies, tag names, event/condition tables, various state conditions, printout report functions,
touch screen display diagrams, and I/O configurations. The work station CRT interface shall
offer the operator the ability to take manual control of a process parameter if the test engineer
has allowed for such manual control action.
The work station shall be considered as peripheral to a remote process controller or
controllers. This occurs once a controller has been instructed as to control strategies of the
particular process. The work station shall be able to communicate with multiple controllers.
Communications shall be via isolated twisted wire pair. The work station shall be able to pass
multiple procedures to a controller. Therefore, in the event of inadvertent damage to the
interconnecting cable, the controller can perform many procedures in sequence until repairs can
be made.
It is recommended that the control system have the actual control strategy intelligence
device located as close as possible to the process itself. This device would typically be termed
the controller.
Control Components
The control elements shall be the heart of the control system. All control functions shall
be performed by this unit requiring no additional hardware or software including start-up,
operation, and shut-down. The controller shall have the ability to implement 32 PID, PI, PD,
52
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I, P, D, error square, bias, ratio, lead/lag, or dead time control loop algorithms and carry them
out in the course of an individual control strategy. The control output capability shall include
a minimum of thirty-two loop control signals.
200 Analog Input Signals
500 Discrete I/O Signals
Additional channel capability to support frequency, period, and totalized data.
I/O Modules
The I/O modules are connected to their respective controller. The I/O modules shall
have the capability to connect to all commonly used industrial sensors, transmitters, and
preconditioned signals. Tlie I/O structure shall provide a high degree of flexibility to be cost
effective from an initial purchase and installation standpoint. The I/O modules shall have
environmental temperature and selective humidity ratings so that they are suitable for mounting
at the process. The system I/O shall measure each input (analog or discrete) and update each
output (analog or discrete) multiple times per second.
The I/O module wire terminations shall be designed in such a way that process sensor
wires do not require disconnection in order to repair or replace module electronic components.
The I/O modules shall be equipped to perform run time diagnostics in conjunction with the
controller.
It is urged that analog I/O resolution be 12 bits or better. The system I/O module
capability shall offer the following:
Available Inputs:
Voltage (DC) +25 MV, +100 MV, +1V, +10.0V
Currents (DC) 4- 20 MA
Thermocouples J, K, T, E, R, S, B types - cold junction compensation & linearization
incl.
Contact Closures Dry contact (open or closed)
RTD's 100 Ohm platinum
Discrete 30VDC, 60VDC, 120VDC, 120VAC
Pulse 0 - 65,000 counts
Serial RS-232, IEE-488 from analyzers
Available Outputs:
Voltages (DC) 0-5V, 0-10.0V
Currents 1-5 MA, 4-20 MA
Discrete 60 VDC, 120VDC, 200VDC, 120VAC
Time Proportional
Pulse Train
Trigger Output or Trigger Input
Stepper Motor Output
53
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Uninterruptible Power Supply (UPS)
An uninterruptible power supply shall be supplied to protect the system from
undesirable system shut-down and/or loss of process control programs and data. Each process
controller and its associated I/O modules shall be protected by a UPS. Upon loss of AC power
to the controller or I/O module, the UPS battery backup power shall maintain the scheduled
process control procedure or sequenced procedure for up to 2-1/2 hours.
Environmental
The work station shall be placed in a control room that is normally air-conditioned for
personnel and instrument comfort. Nevertheless, equipment shall be rated to continue operating
normally under the following environmental conditions:
Temperature 10 - 45°C
Humidity 20 - 80 percent noncondensing
The control elements an I/O modules may be located next to process equipment in
equipment halls or on the outside. Minimum requirements for these components are:
Temperature 0 - 60°C
Humidity 10 - 90 percent noncondensing
Required components will be mounted in NEMA enclosures to protect them from the
environment in particularly hostile areas.
The overall system main components will be subjected to routine vibration levels from
the environment and process equipment operation. Positive evaluation shall be given to those
systems publishing vibration specifications. Vibration specifications should be presented for all
three axes (Verticle, Horizontal, Transverse). Favorable evaluation would be given to those
systems meeting or exceeding the data presented below:
Work Station 5-15 Hz0.0020"
16-33 Hz
Controller, I/O 5-15 Hz0.060"
Module, and UPS 16-25 Hz0.040"
26-33 Hz0.020"
34-40 HzO.010"
3.4.7 Product Control System
Construction, operation, and evaluation of the prototype low-NOx burner system will
allow the determination of which control loops, sensors, and data are important and are essential
to operate a system of this kind. It will also permit the optimization of the fuel train and various
other aspects of the design. With this information, an optimum control system for the
application can be specified. Microprocessor technology today provides the system designer with
great flexibility at ever decreasing cost. Without the fundamental knowledge of all requirements
of the system to be controlled a system can not be optimized. At this time, reduction in the
scope of the proposed control system for the prototype would be speculation and may result in
an inflexible system that would not be in the interest of this program. Another important aspect
of the design of any product is the expected product life cycle and the number of units over
54
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which the development cost must be amortized. It appears that the number of units that could
be allocated to a single supplier are in the hundreds rather than thousands. This restriction
would lead to less customization than would otherwise be possible, i.e. commercially available
control systems should be adapted for the application.
55
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SECTION 4
CONCLUSIONS
The initial objective of this project was to design, fabricate, install and evaluate the
EPA low-NOx heavy oil burner for an industrial package boiler in the 59 to 74 MW (200 to
250 MMBtu/hr) thermal input range. Early in the project, this objective was revised in two
ways. The capacity range for the burner was lowered and broadened because (1) almost no
industrial boilers in the 59 to 74 MW range were firing residual oil to serve as a demonstration,
and (2) most operators who could use the burner for low-NOx firing of nitrated waste had boilers
in the 15 to 29 MW (50 to 100 MMBtu/hr) thermal input range. The design range was
accordingly changed to 15 to 59 MW (50 to 200 MMBtu/hr).
The second revision of the objective was to respond to peer review comments on the
previous evaluation of the EPA burner on an enhanced oil recovery steam generator. The
panel concluded that the earlier design was not appropriate for industrial boiler applications
because of slow thermal response and unacceptable space requirements. Accordingly, the
objective was modified to attempt to adapt the earlier design to address the peer review
comments without conducting further developmental testing.
In addressing these objectives, the design development effort in the current project led
to selection of the lightweight refractory precombustor/burner design with boiler sidefire air as
discussed in the previous pages. Although this burner was not fabricated and evaluated in the
field, the following conclusions on the design are made based on the process engineering
analyses done as part of the design development.
Emissions Performance
The estimated performance of the design based on previous test results and kinetic
estimates is 85 ppm at 3 percent oxygen. The emission goal selected for this program was 100
to 125 ppm, so the final design should give sufficient margin to meet the emission performance
demands of the intended market.
Burner Performance
The use of the lightweight refractory should allow thermal response during startup,
shutdown and load swings comparable to conventional burners and should not constrain
industrial boiler applications. The burner is smaller, much lighter, and cheaper than the earlier
EPA oil burner design. The control logic during start-up is more complex due to the two-stage
operation, but not out of line with new boilers with advanced low-NOx systems.
56
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Market Niche
The burner addresses a need for both high nitrogen residual oil firing, and cofiring of
nitrated wastes. Conventional low-NOx burners for high-capacity package boilers firing high
nitrogen residual oil cannot lower emissions below the 250 to 350 ppm range without causing
flame impingement, combustible emissions, or instabilities. With waste cofiring, the unique hot
first stage used in the burner design offers simultaneous high waste destruction efficiency and
low-NOx emissions. This burner avoids the problem with other burners where measures taken
to lower NOx are counterproductive for high waste thermal destruction.
Reliability
The present design uses lightweight refractory to improve thermal response and reduce
failure risk from thermal shock. However, the design increases the risk of mechanical failure
and overtemperature. The upper temperature limit on the lightweight refractory specified in the
design is 1570 to 1649°C (2850 to 3000°F). The material has been extensively used in heat
treating furnaces with quiescent flows at temperatures below 1540°C (2800°F). The primary
concern with the present application is the turbulent, fuel rich environment with temperatures
approaching 1570°C (2850°F). The subscale endurance tests of the material done in the present
program showed little materials degradation for the design temperature tests. The
overtemperature failure mode tests where temperatures were deliberately run above 1570°C
(2850°F) showed some destruction of the "Unikote S" surface spray coating. The refractory
manufacturer says this coating is applied to give the new refractory surface rigidity prior to
curing. Once the refractory is hardened by curing, the surface coating is no longer needed. The
surface conditions of the refractory should obviously be monitored closely in the first prototype
demonstration of the burner. In a commercial field installation not related to the present
program, lightweight refractory similar to the cylindrical section of the present design has
performed well in the cylindrical section of an enhanced oil recovery steamer for over 6 months
of operation.
Scale-Up
Burner design data are given over a 4:1 capacity range. The general configuration,
stoichiometric ratios, residence times and temperatures all remain nearly identical across that
range, however. Therefore, there is not expected to be significant performance variations with
scale-up.
Developmental Status
Although the burner concept is derived from the earlier EPA oil burner, there are
numerous differences in materials and configuration that were made to address the industrial
boiler market. These changes were reviewed by an industrial peer review panel in November
1986, which concluded the design changes were logical to meet the industrial boiler application
objectives. Nevertheless, optimization testing is needed for the distribution of stage air and the
fuel/air control sequence during startup, shutdown, and load following. Thus, the first prototype
field evaluation will have a larger component of shakedown and confirmatory testing than would
be the case for a simple hardware scale-up.
57
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REFERENCES
1. 49 FR 25152 "Standards of Performance for New Stationary Sources: Industrial,
Commercial-Institutional Steam Generating Units," EPA 40 CFR, Part 60, Subpart Db,
December 16, 1987.
2. Sarofim, A. F., et al., "Mechanisms and Kinetics of NOx Formation: Recent Developments,"
presented at 69th Annual Meeting, AIChE, Chicago, Illinois, November 30, 1976.
3. Brown, R. A., et al., "Investigation of First and Second Stage Variables on Control of NOx
Emissions Using Staged Combustion in a Pulverized Coal Wall-fired Furnace," presented
to 83rd National Meeting, AIChE, Houston, Texas, March 24, 1977.
4., Brown, R. A., et al., "Investigation of Staging Parameters for NOx Control in Both Wall
and Tangentially Coal Fired Boilers," in Proceedings of the Second Stationary Source
Combustion Symposium, Volume III, EPA-600/7-77-073c (NTIS PB271-757), p. 141, July
1977.
5. England, G. C., et al., "Low NOx Combustors for High Nitrogen Liquid Fuels," in
Proceedings of the Joint Symposium on Stationary Combustion NOx Control, Volume V,
EPA-600/9-81-028e (NTIS PB81-236150), p. 115, July 1981.
6. England, G., et al., "Evaluation and Demonstration of Low-NOx Burner Systems for TEOR
Steam Generators: Final Report Field Evaluation of Commercial Prototype Burner,"
EPA-600/7-85-013 (NTIS PB85-185874), March 1985.
7. England, G. C., et al., "Evaluation and Demonstration of Low-NOx Burner Systems for
TEOR Steam Generators, Design Phase Report," EPA-600/7-84-076 (NTIS PB84-224393),
July 1984.
8. England, G. C., et al., "Evaluation and Demonstration of Low-NOx Burner Systems for
TEOR Steam Generators, Test Report: Preliminary Evaluation of Commercial Prototype
Burner," EPA-600/7-83-061 (NTIS PB84-128727), November 1983.
9. Mulholland, J. A. and R. K. Srivastava, "Low NOx, High Efficiency Multistaged Burner:
Fuel Oil Results," Journal of Air Pollution Control Association,, V38, No. 9, pp 1162-1167,
September 1988.
10. Archer, J. et al., "Multistage Combustion of Residual Fuel oil, Part 2," Journal of the
Institute of Fuel, November 1970.
58
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ABBREVIATION S
CAA
Clean Air Act
CAD
Computer aided design
DRE
Destruction and removal efficiency for waste thermal destruction
EOR
Enhanced oil recovery system generator
FR
Firing rate, thermal input
MW
Thermal input in megawatts
MMBtu/hr
Thermal input in million Btu per hour
NEDS
National Emission Data System
ng/J
Emission factor, nanograms pollutant per Joule fired
NOx
Oxides of nitrogen, nitric oxide (NO) and nitrogen dioxide (N02)
NSPS
New Source Performance Standards
OAQPS
EPA Office of Air Quality Planning and Standards
PBS
Package boiler simulator
PIC
Products of incomplete combustion
ppm
Species concentration in parts per million by volume
RCRA
Resource Conservation and Recovery Act
SR
Stoichiometric ratio. Ratio of actual to theoretical air
TFN
Total fired nitrogen
59
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APPENDIX A
SITE SELECTION
A.l APPROACH
The site selection process was to have been an eight step sequence as outlined below.
Prior to truncation of the project scope because of funding limitations, five candidate sites had
been identified through Step 5 and one candidate through Step 7. The one candidate site that
proceeded through Step 7 eventually declined to participate after a high level management
review within the company. Site visits were planned for the other five candidates prior to the
curtailment of the site selection process.
The site selection process was initiated by first outlining the specifications of the boiler
at a potential host site . These specifications initially included a firing capacity in the range of
59 to 73 MW (200 to 250 MMBtu/hr) and are summarized in Table A-l. As it became obvious
that the number of candidate boilers that met these specifications, particularly the firing capacity,
were very limited, the specifications were broadened to include firing capacities as low as 36 MW
(125 MMBtu/hr). In either case the following procedure was followed in obtaining a potential
host site.
1. Obtain lists of potential boiler sites (sources will be identified later)
2. Make initial telephone contact with company to determine:
• If boiler was operable and able to run on heavy fuel
• If there was an interest in the program
• Responsible individuals to decide availability of site and interest of the
company
3. If interest expressed in "2", send letter to responsible individual
4. Followup telephone call to answer questions, check progress, and level of interest
5. Screen candidates for possible site visits
6. Make site visit, discuss with responsible parties
7. Screen candidates and make a formal request
8. Enter into a formal agreement with host site
The approach and progress in each of these steps is outlined in the following sections.
60
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TABLE A-l. SITE SELECTION CRITERIA
Packaged boiler -- 2 drum D-type
Single burner No. 6 oil/gas (high N oil)
59 to 73 MW thermal input (200 to 250 MMBtu/hr)
Air preheat or economizer
Spare capacity and schedule flexibility
High nitrogen waste generation
NOx problem or interest in control technology
Existing Coen burner and controls
Space available and accessible for retrofit
Continuous steam demand
Well instrumented
Skilled operators/maintenance staff
Willingness of host site
Proximity to Acurex and Coen
61
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A.l.l Site Lists
Lists of potential sites were obtained from the following sources:
• Industry trade groups
• Air pollution regulatory agencies (local, state, federal)
• National Emissions Data System (NEDS)
• California Air Resources Board boiler data (RAMOFF)
• Chemical companies with potential of having nitrated wastes
• Babcock & Wilcox large package boiler sales lists
• Retrofit burner manufacturers installation lists
• Radian Report on Boiler Installations (from Power Magazine)
• Army headquarters
• Navy headquarters
• Air Force headquarters
• Miscellaneous government sources
DOD
DOE
NASA
GSA
U.S. Post Office
Veterans Administration
EPA Federal Facility Coordinator
A brief comment on the effectiveness of each of these sources is given in the sections
that follow.
A.12 Industry Trade Groups
Table A-2 lists the industrial trade groups that were contacted. The industrial trade
groups did not generally supply additional leads beyond those received from the independant
contacts with their constituent members.
A.l J Air Pollution Regulatory Agencies
Table A-3 lists those air pollution regulatory agencies that were contacted. Because many
districts do not have NOx control regulations on old boilers of this size, they often were either
not aware of boilers firing No. 6 oil or were not aware of any that had a NOx control problem.
A few districts were quite helpful in providing what information they had on boilers in the size
range of interest.
It was hoped that the air pollution agencies could provide leads to an oil fired boiler that
was having trouble meeting NOx regulations. However, this did not occur due to three reasons:
(1) lack of NOx regulations for boilers; (2) few single burner package boilers in this size range;
and (3) very low current firing of No. 6 oil as a boiler fuel. However, if further site selection
is required, it is recommended that further contacts be made with air pollution control agencies.
Contacts should be focused in those regions which are in nonattainment for ozone or NOx
and/or where No. 6 fuel oil is most likely to be utilized. Such regions could include the
Southeast (Texas, Louisiana) or the Northeast (New England) where a high percentage of fuel
oil is consumed.
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TABLE A-2. INDUSTRY TRADE ASSOCIATION CONTACTS
Organization Location Contact
Western Oil and Gas Association
Assoc. of Washington Business
Oil Heat Inst, of Washington
Northwest Pulp & Paper Assoc.
American Boiler Manufacturers
Association
Council of Industrial Boiler
Operators
Texas Chemical Council
Texas Mid Cont. Oil & Gas
Association
American Petroleum Industry
Chemical Manufacturers Assoc.
Southern California Gas
Gas Research Institute
Seattle, WA
Seattle, WA
Seattle, WA
Seattle, WA
Arlington, VA
Burke, VA
Austin, TX
Austin, TX
Washington, DC
Washington, DC
Los Angeles, CA
Chicago, IL
D. Vogelquist
R. Van Gohren
E. Bishop
L. Rust
W. Axtman
W.Marx
J. Fisher
B. Landerbeck
E. Crockette
P. Duff
J. Gardetta
R. Kurzynske
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TABLE A-3. AIR POLLUTION REGULATORY AGENCY CONTACTS
Organization
Location
Contact
Puget Sound APCD
Texas Air Control Board
EPA Region 9
State of Florida Dept. of
Environmental Region
NY Dept. of Environment
NY Dept. of Environment
Bay Area APCD
NJ Bureau of Air
Pollution Control
Penn. Bureau of Air
Quality Control
Kern County APCD
California Air Resources
Board
Connecticut Department
Environmental Prot.
South Coast AQMD
Ventura APCD
San Diego APCD
Seattle, WA
Houston, TX
San Francisco, CA
Tallahassee, FL
Albany, NY
Warreburg, NY
San Francisco, CA
Trenton, NJ
Harrisburg, PA
F. Austin
S. Keil
C. Seeley
S. Suec
R. Warland
M. Delawater
S. Hill
W. O'Sullivan
J. Walker
Bakersfield, CA
Sacramento, CA R. Menebroker
Hartford, CT
El Monte, CA
Ventura, CA
San Diego, CA
J.Royce
M. Cruz
C. Kraufe
J. Lake
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A. 1.4 National Emissions Data System (NEDS)
Early in the site selection process the EPA was contacted to provide a listing of residual
oil-fired boilers in two size groups: 53 to 73 MW heat input (180 to 250 MMBtu/hr) and 30 to
53 MW heat input (100 to 180 MMBtu/hr). These listing are organized alphabetically by state,
then by county, and finally by company. Although this file is constantly being updated, it is not
a comprehensive listing. It was found that many of the contacts made through these listing were:
• No longer firing oil
• Multiple burner and/or field erected boilers
• No longer operational
• Had capability to fire oil at one time but were firing other fuels
The listings were prioritized by first contacting those companies that might also be
producing a highly nitrated waste, might be under a regulatory constraint (California, Texas,
Louisiana, New Jersey, New York, and Pennsylvania), or might have a higher probability of using
No. 6 fuel oil (Northeast, South, or Northwest). It was also soon found that may of the large
boilers listed in the pulp and paper industry had the capability to fire oil but were often wood
or wood chip fired stokers and not packaged boilers. Therefore, the pulp and paper industry
received a lower priority than others such as the chemical industry.
These lists were also compared to other sources used in the site survey process to
compliment or verify the NEDS data. Primarily, the NEDS data provided an initial identifica-
tion of companies with boilers in the size ranges of interest.
A.1.5 California Air Resources Board (CARB)
One initial approach was to seek a site within California for two reasons: 1) Air pollution
regulations are the most stringent in the nation especially with regard to NOx; and 2) The
logistics of site construction and testing would be simplified by proximity to Coen and Acurex.
To identify local candidate sites, the data bank assembled by the California Air Resources Board
(CARB) for the NEDS was obtained. This data bank provided more information then reported
in the NTEDS for California, and additional boilers were identified as candidates. Unfortunately,
although many had once had the capability of firing No. 6, most were now firing natural gas due
to lower costs.
A.1.6 Chemical Companies with Nitrated Waste
In 1983, EPA-Cincinnati conducted a study in which hazardous waste compounds were
identified and the manufacturing process that produced these wastes were given. The
compounds were categorized into several classes including one class of wastes containing
nitrogen. From these lists, those chemical industries that produced a relatively high volume of
waste were identified. From the Chemical Week Buying Guide Directory, companies involved
in the production of candidate compounds were identified. Table A-4 lists those nitrated
compounds with the associated companies involved in their manufacture. Again, cross reference
to other boiler lists was attempted. In many cases, common company names were identified but
it was not always known if the particular sites identified also manufactured the nitrated
compounds. Several high priority sites were found through this avenue. On the whole, either
the manufacturing site did not have a large boiler, or they were no longer manufacturing the
compound in question, or the amount of waste had been minimized through recent waste
recycle/reuse refinements in the manufacturing process.
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TABLE A-4. NITRATED COMPOUND
MANUFACTURERS
Nitrobenzene
Allied Chemical
Dupont
First Chemical Corp.
Mobay Chemical Corp.
Monsanto
Rubicon Chemical Inc.
McKesson Chemical Co.
Acrvlonitrile
Fallek Chemical Corp.
B. F. Goodrich Chemical Co. Div.
Dupont
Monsanto
Vistron Corp. (Std Oil Co of Ohio)
ICC
Pyridines
Union Carbide, Danbury, CT
Koppers Co. (Chemical) Pittsburgh, PA
Nepara Chemical Co. Inc.
Reiley Tar Chemical Corp.
Aniline
Air Products and Chemicals
American Cyanamid Co. (Organic Chem Div)
Dupont
First Chemical Corp.
Mobay Chemical Corp.
Uniroyal
All cvlamines
Air Products and Chemicals
ARMAK and Chem. Div.
Ashland Chem. Co.
BASF Wyandotte Corp.
Ethyl Corp Int'l Chem. Div.
Hess, John R. and Sons
Mars Chemical Corp.
Onyx Chem. Co.
Union Carbide, Chemicals and Plastics
(continued)
66
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TABLE A-4. (continued)
Diphenvlamine CDPA'I
Smith, i.g., Frederick Chem. Co.
American Cyanamid
McKesson Chemical Co.
Mobay Chemical Corp.
Uniroyal Inc.
Diphenvlmethane Dissovante
Mobay Chemical Corp.
Rubicon Chemical Inc.
Upjohn Co. (the Polymer Chem. Div.)
Carbamate Pesticides Carbarvl
Agrico Chem. Co.
Alpha International Chemical Inc.
Ashland Chem. Co. (Ind'l Chems and Solvents Div.)
Baker, J. T.
Captree Chemical Co.
Harshaw Chem Col.
Intsel Corp.
Mineral Resources and Development Corp.
Philipp Brothers Chemical Inc.
Urea
Ashland Chemical Co.
Borden Chem. Div. of Borden
Columbia Nitrogen Corp.
ICC Industries Inc.
McKesson Chem. Co.
Olin Corp, Stanford, CT
Stinner Oil and Chemical
Thompson-Howard Chem. Co.
Union Chemicals Div. of Unocal
Vistron, Cleveland, Ohio
(continued)
67
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TABLE A-4. (continued)
Rubber Industrial Wastes (Nitrobenzene)
Cities Service Co, Columbia Chem. Div. Tennessee Chem. Co.
Dow Corning Corp.
Dupont
Exxon Chem. Co., Houston, Texas
Firestone Synthetic Rubber and Latex Co., Akron, Ohio
B. F. Goodrich, Chem. Group
Thiokol Corp. Ordnance
Uniroyal
U.S. Industrial Chem.
Toluene-2-4 Diamine
Air Products and Chemicals
Olin Corp.
Dinitrotoluene
Air Products and Chemicals
Dupont
Dinitrophenols (Dyestuff intermediate)
Blue Spruce Co.
Atrazine
Ciba-Geigy Corp.
Hydrazine
A&S Corp.
Aceto Chem. Co.
Fairmont Chem. Co.
Hummel Chem. Co.
ICC Industries Inc.
Mobay Chemical Corp.
68
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A.1.7 Babcock and Wilcox Boiler Lists
Early in the search for a site, two Babcok and Wilcox boiler designs produced in the
late sixties and early seventies were explored as candidates for the low-NOx burner retrofit.
One design, known as an FM boiler, has a single, large burner and a relatively large firebox.
This design was produced for capacities up to 114,000 kg/hr (250,000 lbs/hr) of steam. Fourteen
sites were initially identified for this design. The second design produced in the early sixties is
the cyclopac boiler which has a removable oil-fired cyclone burner mounted on one end of the
boiler. This design is also ideal for retrofit with the low NOx burner design since the original
burner was fairly large as well. Nine cyclopac boiler sites were initially identified but none were
still in service.
If further site selection is required it is recommended that the other major package
boiler manufacturers (CE, Foster Wheeler, Riley Stoker) be contacted for similar lists.
A.1.8 Retrofit Burner Manufacturer Lists
A major burner retrofit manufacturer was able to provide the project with a list of sites
which had made a burner conversion within the past 15 years. Only those sites were selected
that had the capability of burning fuel oil and were within the capacity range of interest. Initially
this capacity range was from 64,000 to 89,000 kg/hr (140,000 to 195,000 lb/hr) of steam but a
second list was generated in the range of 55,000 to 68,000 kg/hr (120,000 to 150,000 lb/hr) of
steam. The first list consisted of 107 sites of which all were contacted. The second screening
produced about 140 potential sites of which most were contacted prior to cessation of this
activity. Many of the sites in the second listing however were at the same companies as the first
list. TTiese lists proved to be the most useful information source of any of the sources reviewed.
In most cases the data on the boiler was reliable and a contact was provided at the company.
A.1.9 Radian Report
The EPA Project Officer provided a list of boilers compiled from sales information
presented in Power Magazine dating from 1974. This list included 24 boilers in the size range
and fuel of interest. The fuels were listed as oil, oil and gas, or No. 6 oil. It was not specified
if those listed as oil were heavy or light oil-fired. However, most of these listings were duplicates
of information provided from other sources.
A.1.10 Navy
The Navy has many boilers associated with its shipyards. It also generates considerable
nitrated waste in the form of specialized torpedo motor fuel. Thus it seemed that the Navy
would be a natural host site for this project. The primary source of information was the Navy
Energy and Environmental Support Activity, NEESA, located at Port Hueneme, California. The
energy office maintains information on the size and fuel use all the Navy boilers. The
environmental office oversees research on the overall environmental problems in the Navy and
in particular disposal of hazardous waste.
Initial discussion with personnel in the energy office revealed a few boilers in the size
range of interest (52 to 73 MW) (180 - 250 MMBtu/hr input). In response to a letter explaining
the program and requesting participation, NEESA took the position that they could not
participate in the program due to legal problems associated with liability for storage,
transportation and burning of hazardous waste. Simultaneously with the inquiry, a number of
other Navy contacts were made including the following:
69
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• Naval Surface Weapons Center, Dahlgren, VA (Hazardous Waste Research)
• Naval Facilities Engineering Command, Washington, DC
• Naval Facilities Engineering Command, Philadelphia, PA
• Philadelphia Naval Shipyard
• Naval Ordnance Station, Indian Head, Maryland
• Puget Sound Naval Shipyards, Seattle, Washington
• U.S. Navy Base, Keyport, Washington
None of these contacts led to a promising site and usually the contact directed the inquiry to
Washington which in turn directed it back to NEESA at Port Hueneme. Thus, further inquiries
with the Navy were terminated.
A.1.11 Army
The Army maintains boilers at a number of their bases and generates some nitrated
waste from the production of munitions. The following organizations and/or sites were
contacted:
• Construction Engineering Research Lab (CERL), U.S. Army, Champaign, IL
(Boiler Lists)
• Holsten Ammunition Plan, Kingsport, TN
• Test and Evaluation Command (TECOM), Aberdeen Proving Ground, MD
• Rock Island Arsenal, Rock Island, IL
• Picatinny Arsenal, Dover, NJ
• Fort Lewis, Seattle, WA
• Army Material Command Headquarters, Alexandria, VA
• Toxic and Hazardous Material Agency, U.S. Army Aberdeen, MD
• Army Environmental Hygiene Agency (AEHA) MD
Most of the boilers found on Army bases were used for space heating with capacities less than
18,000 kg/hr (40,000 lb/hr) of steam.
The few large boilers associated with munitions production were either coal-fired or
no longer in service. This avenue of inquiry was therefore discontinued.
A.1.12 Air Force
The Air Force also generates a nitrated waste in the form of hydrazine and operates
boilers at most of its bases. It also has a coordinated environmental hazardous waste program.
The Air Force maintains its inventory and coordinates its hazardous program from Tyndall Air
Force Base in Florida. A solicitation letter was sent to the hazardous waste coordinator but
because of lack of funds and no boilers in the size range of interest they declined to participate
in the program. A few individual bases were contacted including:
• Air Force Rocket Propulsion Lab, Edwards Air Force Base, CA
• Vandenberg Air Force Base, Santa Maria, CA
• McCord Air Force Base, Tacoma, WA
• Wright Patterson Air Force Base, Dayton, O
70
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Currently the hydrazine from the rocket fuel is shipped off site for disposal,
boiler sizes were in the range of 23,000 to 27,000 kg/hr of steam (50,000 to 60,000
steam). No promising site were found and this avenue of inquiry was terminated.
A.1.13 Miscellaneous Government Sources
Other government sources that were contacted included the following:
• NASA
• Department of Energy, Washington, DC
• Tennessee Valley Authority, TN
• U.S. Post Office, Washington, DC
• Veterans Administration
• Defense Utilization and Marketing Service, Environmental Protection Department,
Tech Support Division, DOD, Battle Creek, MI
• General Services Administration, Energy Coordinator, Washington, DC
• Environmental Protection Agency, Federal Facilities Coordinator
• Department of Defense, Defense Environmental Leadership Group, Washington,
DC
The latter three were very helpful in providing contacts at the Army, Air Force, Navy,
TVA, DOE, Post Office, and Veterans Administration. Unfortunately, none of these leads
resulted in a high priority site. The DOD Defense Environmental Leadership Group provided
numerous contacts within the military and seemed to be genuinely interested in the program.
However, contacts within those organizations would often refer back to the Defense
Environmental Leadership Group. Thus, this avenue was also terminated in favor of finding a
higher probability private sector industrial site.
A.1.14 Contacts
As the site lists were developed, an attempt was made to prioritize the potential site
for an initial telephone contact. High priority sites included those that might also have a
nitrated waste problem, a NOx regulatory problem, or had a high probability of using a No. 6
fuel oil. Sites located on the West Coast also were given a higher priority.
The initial strategy was to make a telephone contact with the person responsible for
environmental affairs. Questions on the characteristics of the boiler were often directed to the
person responsible for the operation of the boiler. If the boiler characteristics met the required
specification (or nearly met them) and there was an interest expressed, this telephone call would
be followed up by a letter explaining the program and requesting their interest in participation.
A sample copy of this letter is shown in Figure A-l. Figure A-2 shows a more detailed
description of the program which was also sent to most contacts. The incentives cited to
encourage participation included the following:
• Potential to meet and exceed any NOx regulatory requirements
• Ability to dispose of nitrated waste compounds
• A new burner and control system at no cost to the host site
• Return of the boiler to its original condition at the end of the project if so desired
• Public relations benefit for controlling emissions
Typical
lb/hr of
71
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/¦s ACUREX
'fT* Corporation
Energy & Environmental Division
July 31, 1985
Mr. Wayne Turner
Manager For Environmental Affairs
Dow Chemical
2030 W. H. Dow Center
Midland, MI 48674
Reference: Field Evaluation of Low NOjj Heavy Oil Burners
Applied to Industrial Packaged Boilers (EPA Con-
tract No. 68-02-4213, Joe McSorley Project Officer
Tel (919) 541-2920)
Dear Mr. Turner:
As I discussed with you during our recent telephone conver-
sation, Acurex was awarded an EPA competitive procurement for the
full-scale demonstration of a low NOx burner. This program
requires the voluntary participation of an industrial site for
the field retrofit and evaluation of a 200 to 250 million Btu/hr
burner on a packaged boiler burning high-nitrogen residual oil.
The burner will also be evaluated for' the efficient destruction
of liquid nitrated hazardous wastes to demonstrate compliance
with emerging RCRA standards. Coen Company has teamed with
Acurex for the fabrication, installation end host site boiler
modifications. Coen will also support Acurex in various engi-
neering and design efforts.
We are soliciting your assistance in helping us locate
candidate sites which would match the program requirements and
might express interest in participating. The importance of the
program lies in the commercia 1-seale demonstration of the burner
dual capability of low-NOx emissions and efficient waste
destruction despite its use of high nitrated fuels. Thus an
industrial facility which might be faced with permitting or
compliance requirements under both RCRA and CAA standards might
be particularly interested in this demonstration program.
Attached is a brief but more detailed description of the
requirements and goals of this program and our anticipated
approach. I would like to indicate that the shown burner/
combustor configuration is not definitive. Its final configura-
tion and size will depend on the host site boiler and on the
results of scheduled engineering optimization and design phases
of the program.
555 Ciyoe Avenue, P.O. Box 7555, Mountain View. CA 94C39 (*15) 964-3200 Telex 34-6391 TWX 910-7796593
Figure A-l. Sample letter sent to industrial contacts.
72
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We look forward to your support in locating candidate sites.
Your suggestions and ideas will be most gratefully appreciated
and definitely a vital contribution to this program.
Richard A. Brown
Manager, Combustion Laboratory
RAB/sla
Encls.
Figure A-l. (continued).
73
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FIELD EVALUATION OF LOW-NOx HEAVY OIL BURNERS
APPLIED TO INDUSTRIAL PACKAGED BOILERS
PROGRAM DESCRIPTION
1. INTRODUCTION
The recent course of regulatory development has created the
need for a new low emisson industrial boiler burner. This need
arises through the emergence of new standards or the tightening
of existing standards for NOx emissions pursuant to the Clean Air
Act, and for emissions of organic hazardous compounds pursuant to
the Resource Conservation and Recovery Act (RCRA). For new
industrial boilers, N0X reduction is needed to meet the New
Source Performance Standards proposed by EPA June 19, 1984. For
existing sources, stringent NO^ controls are needed for preven-
tion of significant deterioration and emission offset provisions
as an alternative to catalytic reduction.
At the same time as these developments, RCRA is encouraging
thermal destruction of combustible organic hazardous wastes as a
means of resource recovery and as an environmentally necessary
alternative to landfill. EPA standards for destruction and
removal efficiency (DRE) for waste cofiring in industrial boilers
are to be proposed in 1985. Concurrently, landfill disposal of
certain wastes may be entirely banned in the near future. Recent
EPA tests conducted by Acurex have shown industrial boilers to be
very effective in waste destruction as evidenced by an overall
mass averaged DRE of >99.99 percent. Tests have shown, however,
that combustion conditions, conducive to high destruction -- high
temperature, long residence time, high turbulence — are also
conducive to N0X formation in conventional combustors. Thus, the
requirements of the Clean Air Act and RCRA are potentially
divergent. This situation is particularly aggravated if the
wastes contain bound nitrogen. This gives rise to the need for a
combustion system which can simultaneously suppress N0X formation
and efficiently destroy wastes.
EPA is addressing this need through a sequenced burner
scaleup program started in 19B1. The EPA burner uses a high-
temperature, fuel-rich, long-residence time chamber which drives
fuel nitrogen intermediaries toward equilibrium and pyrolizes
waste compounds to intermediaries. The boiler serves as a second
stage to form minimal thermal N0„ while oxidizing waste inter-
mediaries to end products. Tests to date have shown N0„ emis-
sions well below 100 ppm, even with highly nitrated fuel/waste,
and DRE >99.99 percent.
Figure A-2. Field evaluation of low-NOx heavy oil burners applied to
industrial packaged boilers.
74
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At this juncture, the burner has been scaled-up to 55 mil-
lion Btu/hr on a thermally enhanced oil recovery (TEOR) steamer
firing an 0.8 percent nitrogen crude oil. The performance of the
burner was successfully demonstrated by achieving NOx levels of
70 ppm (versus 300 ppm for a conventional burner) with low smoke
and CO emissions and satisfactory thermal efficiency. Accord-
ingly, the next logical step is to scaleup through the size range
used for most industrial boilers, particularly those cofiring
hazardous wastes.
2. OBJECTIVES
The objective of the proposed program is to scaleup, fabri-
cate, and demonstrate a 150 to 250 mil lion Btu/hr burner on a
package boiler. This size range is appropriate as it represents
the upper end of the majority of oil-fired industrial boilers,
particularly those in the chemical industry cofiring wastes. A
package boiler is specified as it presents the sternest challenge
to N0X control and waste destruction with its tight firebox, high
combustion intensity, and short residence time. The goals of the
demonstration are NOx 100 ppm (at 3 percent 0^), CO 35 ppm, smoke
number 4, and operational flexibility and reliability acceptable
to potential users.
3. TECHNICAL APPROACH
The program, spanning a period of 3 years, will be conducted
by the Acurex Corporation with assistance from the Coen Company
during design, fabrication and boiler retrofit phases. Coen
Company will bring the necessary experience, credibility and
realism particularly in the burner design, boiler integration and
system control to ensure industry acceptance.
The technical approach is segmented in the following seven
phases:
1. Industrial Boiler Site Selection
2. Burner Design and Construction
3. Installation and Startup
4. Optimization and Evaluation
5. Destruction of Industrial Waste Tests
6. Restoration
7. Coordination
The following subsection briefly describes the work and
objectives in each of these phases.
Figure A-2. (continued).
75
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3.1 Site Selection
The selection of an industrial packaged boiler for retrofit
and field validation of the low-NOx burner is an important task
in this program because of decisive implication on ease and cost
of retrofit and restoration. In general, the selection will be
based on the following required or desirable site and boiler
cha racter i st ics:
Site
• Spare capacity •
• Space availability
• Continuous steam demand •
• High nitrogen liquid •
waste availability
• Permit application •
status
•
3.2 Burner Pesign and Construction
The preliminary burner design will be based on the scaleup
of the existing 55 million Btu/hr burner. An illusratibn of this
preliminary design retrofit to the industrial boiler is shown in
Figure 1. The combustor is shown in the horizontal position in
line with steam generator. The combustor will use the regenera-
tion concept previously used on the TEOR retrofit project. The
key elements of this design are:
• State-of-the-art Coen SAZ/DAZ burner register tech-
nology for efficient air-fuel mixing and flame shape
• Coen MV steam atomized oil gun for efficient atomi-
zation
• Dual fuel capability with Coen natural gas spuds for
boiler operation on natural gas during preheating of
combustor
• Standard carbon steel material for burner and windbox
with typical temperature limitations to 550°F
• Regenerative combustor design utilizing dual shell
arrangement with approximate outside diameter of 11 ft
• Insulated outer shell for outside surface temperatures
below 100°F
• Primary air bypass vent controlled to retain high
velocity over the inner shell during low loads
• Inner refractory lined shell made of high temperature
carbon steel. Prefired high-alumina ( 90 percent) kiln
bricks for low conductivity and stress resistant prop-
erties over high temperature gradients.
Figure A-2. (continued).
Boiler
150-250 Million Btu/hr
nominal capacity
Packaged design
High nitrogen fuel oil
firing (primary fuel)
Compatible burner confi-
guration (single burner)
Compatible furnace design
("D" type preferred)
76
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• Primary air inlet with controlled vanes to partition
air to the burner and secondary N0X ports
• Combustor transition (interface) and choke area (approx-
imately 4 ft diameter) designed for optimal furnace view
angle and boiler retrofit requirements. Both transition
and choke areas are brick lined as in the main combustor.
• Frontwall N0X ports designed for slow air-gas mixing
required for low N0X
• Boiler furnace sidefire air ports and associated
ducting for rapid and complete mixing to ensure low-CO/
smoke emissions
The burner will be equipped with Coen controls to monitor
and set air flow for optimum stoichiometry and varying steam
loads, primary air vent, burner register positioning, oil vis-
cosity (temperature) control, front- and sidefire air injection,
and total overall excess air. The controls will utilize Coen
proprietary and state-of-the-art microprocessor software to pro-
vide optimum load following capability without increase in smoke
or CO emissions. Coen Company will fabricate the burner and
controls at its Burlingame facility for shipment to the site.
The design and construction of the burner is anticpated to take
12 months.
3 . 3 Installation and Startup
The installation and startup of the combustion system will
be performed by a team of Acurex, Coen, and a general contractor.
This phase of the program estimated to span 5 months will require
boiler and site modifications to retrofit the burner and combus-
tor system. Coen will also modify the existing burner control
system for compatibility with the low-NOx system. The startup
and checkout phase will include preliminary cold flow checks
prior to lightoff. Coen will provide a detailed lightoff se-
quence and check procedure. Low fire combustor refractory curing
will be necessary prior to full load operation.
3.4 Optimization and Field Evaluation
Following the burner startup and checkout tests, the
facility will be subjected to a 2 month detailed optimization
test and 1 month performance evaluation program. The objective
of the optimization tests is to determine the operational
settings of the burner for minimum N0„, CO, and smoke over a wide
range of boiler loads. Thermal and mechanical performance will
also be optimized.
Figure A-2. (continued).
78
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The following primary variables effecting the emission
performance of the burner will be investigated during
optimization tests:
• Burner
-- Fuel atomization (pressure, temperature)
-- Mixing (register air swirl)
-- Firing rate (oil/air flow)
• First stage combustor zone
-- Stoichiometry (typically 0.6 - 0.65 required)
-- Temperature (combustor air preheat)
-- Residence time (burner load, air flow, temperature)
• Second stage injection rate and location
-- Air distribution (choke versus boiler sidefire)
-- Overall excess air (boiler exit)
The objective of the long-term (30 day) emission evaluation
performance tests is to measure burner thermal performance and
emissions under typical plant operation.
3.5 Destruction of Industr ial Wastes Tests
Emission tests will be performed to evaluate the destruction
and removal efficiency (DRE) and PIC emissions during cofiring
with nitrated wastes. The tests will be similar to those per-
formed for the industrial boiler hazardous waste cofiring for the
EPA HWERL in Cincinnati. Liquid nitrated wastes containing
aery 1onitri 1 e, nitrobenzene, aniline or pyridine will be con-
sidered for the test program. If nitrated wastes are not avail-
able at the selected site, spiking of the available liquid waste
with a combination of these organic compounds will be considered
for these tests.
3.6 Restorat i on
Following the completion of the validation and performance
tests the host boiler and facility will be restored to original
conditions unless alternate arrangements are negotiated between
the EPA and the host site. Auxiliary systems such as burner
controls, combustion air fan, secondary air ports, etc. may
remain if the host site agrees.
Figure A-2. (continued).
79
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3. 7 Coord i nat i on
The program will utilize a technical advisory panel to
monitor and provide feedback on the plans, progress and results
of each phase on a routine basis. The panel will be selected in
consultation with EPA from among all groups interested in the
development or implementation of the technology. Suggested
candidate groups are:
• User industries
— Host site
— CMA boiler committee chairman
• Boiler industry
-- CIBO
-- ABKA
-- Burner/boi1er manufacturer
• R&D groups
-- EPA research laboratory
-- EPA/DOE contractors
• Regulatory groups
-- EPA, OAQPS, OSW, regional office
CC/RAB/sla
Figure A-2. (continued).
80
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In return for these benefits the host would be required to:
• Make space available to position the new burner/precombustor
• Allow sufficient downtime to modify the boiler
• Allow the boiler to be operated through a series of test conditions both before
and after the retrofit
• Provide a coordinator from the plant to interact with the EPA and its contractors.
This coordinator would also sit on the Technical Advisory Panel to review design,
construction plans, test plans, and final data
• Provide fuel to run the boiler during the test program (not over and above current
fuel use)
• Provide normal boiler maintenance and operators
• Allow the burner to be operated 6 months after the initial test program
Within a week or so after the potential host site had received the information letter,
a followup telephone call was made to the addressees to answer any questions and to obtain
an initial response. Responses included:
• Need more time to canvass boiler sizes and fuel capabilities at various plants
• Need more information (usually financial impact on the host site - downtime,
fuel costs, manpower requirements, etc.)
• Need to take to higher authority
• No interest (no boilers in size range, not burning No. 6, cannot afford downtime,
•no manpower)
• Interested in defining the next step
If interest was expressed, more details were obtained on the boiler type, specific site
information, duty cycle, regulatory situation, and potential for burning hazardous waste. The
decision procedures and level of management approval was also determined. Finally if there
appeared to be sufficient mutual interest, a site visit was scheduled.
At the site visit, detailed dimensions of the boiler layout were obtained and logistics
were discussed with the responsible plant personnel.
This site would then be compared to other potential sites and a decision made to issue
a formal letter requesting participation. If more than one suitable site were available, a priority
would be established but more than one letter could be issued at one time.
A2 SUMMARY OF CONTACTS
In total over 300 potential sites and/or companies were contacted with regard to this
program. Most of these were terminated for a variety of reasons after the initial phone call.
Letters were sent to the companies listed in Table A-5 and military/government installations
in Table A-6. Followup calls were made to all of these. At the time this activity was put on
hold, it had been decided to expand the boiler specification to include single burner package
boilers down to as low as 55,000 kg/hr (120,000 lbs/hr) of steam. This change considerably
broadened the potential base for site selection and another round of contacts were being
initiated. From the first round, five locations were identified for site visits. Table A-7 lists the
site specifications. All of these sites had expressed an interest in a site visit by Acurex or Coen.
81
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TABLE A-5. INDUSTRY CONTACTS
Organization
Location
Contact
Keysmuth Corp
Austin, TX
A. Askew
Celanese Chem.
Dallas, TX
A. Savage
Exxon Baton Rouge, LA
T. Sullivan
Dupont Deepwater, NJ
A. Pagaw
Texas Eastman
Longview, TX
J. Woolbert
Dupont Wilmington, DE
D. Smith
Dupont Beaumont, TX
R. McClure
Dupont La Place, LA
G. Barge
Arco Pennsylvania, PA
D. Fitts
St. Joseph Light and Power
St. Joseph, MO
S. Brooks
Waldorf Corp.
St. Paul, MN
G. Waterhouse
Cape Industries
Wilmington, NC
B. Gravowshi
Dow Chemical
La Porte, TX
M. Dillon
Shell Oil Seattle, WA
D. Gillet
Longview Fiber
Seattle, WA
B. Guide
Seattle Steam Corp.
Seattle, WA
F. Marshall
Pacific Power Co.
Portland, OR
B. Missen
Freeport Sulfur
New Orleans, LA
M. Wiliconsin
Chevron Richmond, CA
P. Davis
B. F. Goodrich
Cleveland, OH
L. Clark
Mobay Chemical
Pittsburg, PA
L. Hughes
Std. Oil of Ohio
Cleveland, OH
K. Blower
Monsanto
St. Louis, MO
G. L. Jessee
Exxon Baton Rouge, LA
E. Sales
Union Oil
Los Angeles, CA
M. Dougherty
Air Products and Chem.
Allentown, PA
J. Spata
BASF Wyandotte
Parssippany, NJ
D. Anderson
Koppers Co.
Pittsburgh, PA
M. Urlassik
American Cyanamid
Wayne, NJ
R. Dennis
First Chemical Corp.
Pascagoula, MS
T. Kissinger
Uniroyal Middleburg, CT
J. Gulak
Harshaw Chem. Co.
Cleveland, OH
A. Koes
Rubicon Chem
Gusmar, LA
M. Keene
Kerr McGee
Tiona, CA
M. G. Edmonsen
Allied Chemical Co.
Morristown, NJ
W. M. Reiter
Texaco USA
Houston, TX
D. H. Schmude
AMOCO Chemical
Chicago, IL
J. Huddle
Boise Cascade
Portland, OR
A. Mick
Warren Petroleum
Montebello, TX
B. Langley
Ashland Chemical
Columbus, OH
R. Sterrit
Ethyl Corp.
Baton Rouge, LA
D. Park
(continued)
82
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TABLE A-5. (continued)
Organization
Location
Contact
Union Chemical
Los Angles, CA
F. Walters
Onyx Chem. Co.
Jersey City, NJ
J. Niermiec
Mars Chem. Corp.
Atlanta, GA
J. Newton
Shell Oil Co.
Houston, TX
G. Barrington
Crown Zellerbach
Seattle, WA
J. Walters
Texaco Chem.
Bellaire, TX
G. Edwards
International Mining & Chem. Terra Haute, IN
M. McKee
McKesson Chem. Corp.
Fort Wayne, IN
A. Peters
U. S. Industrial Chem.
Cincinnati, OH
D. Hall
Warren Petroleum
Houston, TX
L. Reed
C&H Sugar
Crockett, CA
J. Shapak
Louisiana Pacific
Sonora, CA
E. Taylor
Weyerhauser
Seattle, WA
B. Anderson
Simpson Paper
Andersen, CA
S. Narium
Masonite Hardboard
Ukiah, CA
S. Jennings
Mobil Chem. Co
Houston, TX
P. Mullin
Union Carbide
NJ
E. Southard
Union Carbide
NJ
R. Kelley
Union Carbide
Houston, TX
J. Holliday
Dow Chemical
Midland, MI
D. Wilson
Dow Chemical
Midland, MMI
W. Turna
Thiokol
Shreveport, LA
E. Sears
Crown Zellerbach
Antioch, CA
E. Chisin
General Electric
Waterford, NY
A. North
Boeing Co.
Seattle, WA
D. Smukouski
Upjohn
Kalamazoo, MI
S. Karas
Southern California Edison
Los Angeles, CA
L. Radak
Pfizer Inc.
Groton, CT
R. Pfisterer
Uniroyal Chem.
Nantuckett, CT
D. Kogut
Vista Chem.
Westland, LA
M. Hayes
Julian Material
Geisner, LA
B. Smith
P.P.G. Industries
Pittsburg, PA
M. Samuelson
P.P.G. Industries
Lake, LA
A. Pluche
Air Products and Chem
Garbiel, LA
T. Tollwater
Pratt & Whitney
Pensacola, FL
T. Butler
Pratt & Whitney
E. Hartford, CT
A. Caldwall
Vero Beach Power Pit.
Vero B., FL
M. Mossey
Marathon Oil
Geryville, LA
B. Harmon
Gulf Power
Pensacola, FL
N. Hershbeig
Monsanto Fibers
Pensacola, FL
J. Wylie
American Cyanamid
Milton, FL
N. Sharitz
(continued)
83
-------
TABLE A-5. (continued)
Organization
Location
Contact
American Cyanamid
Westwego, LA
J. Schnel
Vanderbilt Chemical
Connecticut
H. Baer
Firestone
Akron, OH
J. Larman
Goodyear Tire and Rubber
Akron, OH
J. Surklia
Dupont
Orange, TX
B. Beck
Union Carbide
S. Charleston, W. VA
D. Knudsen
Air Products and Chem.
Pasadena, TX
B. Martine
Uniroyal Chem
Nantuckett, CT
G. Arndt
Monsanto
Aniston, AL
B. Chevar
Union Carbide
Texas City, TX
R. O'Brien
Dow Chemical
Texas
J. Robertson
84
-------
TABLE A-6. MILITARY AND GOVERNMENT CONTACTS
Organization
Location
Contact
EPA Fed. Facilities Coord.
Washington, DC
L. Herwig
DOD Fed Facilities Coord.
Washington, DC
P. Fink
Defense Utilization and
Battle Creek, MI
L. Daley
Marketing Service -- Environ. Prot. Dept.
Navy - Chesapeake Bay
Washington, DC
S. Buckley
Defense Envir. Leadership Grp Washington, DC
C. Schaeffer
Dept. of Defense
Washington, DC
A. Talts
Vandenberg AFB
Santa Maria, CA
L. Mitchell
Army Command HQ
Alexandria, VA
B. Hasselkus
Air Force Rocket Prop Lab
Edwards AFB, CA
J. Marshall
U.S. Navy-NEESA
Pt. Hueneme, CA
P. Jones
U.S. Navy-NEESA
Pt. Hueneme, CA
R. Winters
U.S. Navy-Naval Ord
Indian Head, MD
T. Woo
Naval Surface Weapon Ctr
Dahlgren, VA
D. Knudsen
U.S. Air Force
Tyndall AFB, FL
S. Joshi
U.S. Army-Fort Lewis
Seattle, WA
S. Miller
U.S. Navy-Puget Sound
Seattle, WA
R. Roholt
Naval Shipyard
U.S. Navy Base
Groton, CT
W. Mansfield
TVA
Tennessee
T. Swanson
U.S. Army (Cor. of Engr.)
Washington, DC
L. Keller
DOE (Energy Office)
Washington, DC
E. Tuttle
U.S. Post Office
Washington, DC
F. Delisio
Veterans Adm.
Washington, DC
J. Garg
GSA
Washington, DC
J. Facaus
U.S. Army, AMC
Alexandria, VA
Maj. Trageirer
NASA
Washington, DC
D. Apsia
DOE
Germantown, MD
C. Wetty
U.S. Army-Rock Island
Rock Island, IL
C. Sarntdman
Arsenal
U.S. Army-Rock Island
Rock Island, IL
R. Shinbori
Arsenal
U.S. Army-Picatinny Arsenel
Dover, NJ
P. Prahlin
85
-------
TABLE A-7. BOILER SPECIFICATIONS FOR HIGH PRIORITY SITES
Number
Boilers
Boiler
Manufacturer
Boiler
size
(Ibs/hr)
No.
Burners
Mfg.
Type
Fuel
Waste
Contact
Consolidated Edison
New York, NY
20
Foster Wheeler
150,000
2, FW
D
Oil
(potential
problem)
None
Dom Mormile
General Electric
Selkirk, NY
2
Babcock Wilcox
Combustion
Engineering
150,000
(90,000 to
100,000)
150,000
1, Coen
1, CE
D
A
Gas, oil
distillate
Gas, oil
1 burns tar
(Haz waste)
Tom Wrobleski
Monsanto
Indian Orchard, MA
1
Babcox & Wilcox
150,000
1, Coen
D
Gas, oil
waste (not
nitrated)
Nonchlorinated
GeorgeLemos
Monsanto
Fayetteville, NC
2
175,000
1, Coen
Oil
Possible NH3
waste
Phil Pruette
Tri Valley
Stockton, CA
4
1
1
Nebraska
Nebraska
Nebraska
125,000
100,000
150,000
1, Coen
1, Coen
1, Low-NOx
Peabody
D
D
D
Gas, oil
(-6N)
None
H. Griffiths
-------
Telephone discussion were continuing with 12 additional sites. An additional group of over
100 remained on the list to be contacted with boilers in the smaller size range. In addition, plans
were underway to scan the list of companies already contacted to determine if boilers in the
range of 55,000 to 82,000 kg/hr (120,000 to 180,000 lbs/hr) of steam might be available.
87
-------
APPENDIX B
SUBSCALE REFRACTORY ENDURANCE TESTS1
B.l INTRODUCTION
This appendix summarizes a test series run to obtain endurance data for the lightweight
refractory section at combustion conditions simulating the design conditions of the full scale
burner. Three test phases were run. Initially, a nominal four week steady exposure test was run
to obtain durability data. This was followed by a one week thermal transient test which tested
the ability of the refractory to adapt to temperature ramps representative of industrial boiler
load swings and start ups. The third phase consisted of another 4 days of steady state testing
at temperatures beyond the range for which the refractory was designed. Since the testing was
focused on materials durability, the primary test data was materials examination after each
phase of testing and monitoring of outer shell temperatures to detect any change in thermal
conductivity or heat shorts caused by refractory cracking. With this type of refractory, the failure
modes of concern are weakening of surface strength and increased friability caused by
overtemperature, and propagation of surface cracks in the Saffil coating caused by thermal
stresses. Due to the limitations of the sub-scale system, the test conditions which most closely
simulate full-scale materials performance cannot be simultaneously run with the conditions
simulating full scale NOx performance. Therefore, the NOx emission results are not
representative of the performance potential of the design.
B2 FACILITY
The tests were run on the EPA versatile pilot-scale package boiler simulator (PBS) located
at the Air and Energy Engineering Research Laboratory in Research Triangle Park, NC. The
PBS configuration used for the refractory durability tests included the vertical down-fired
precombustor section shown in Figure B-l. The facility was adapted to firing No. 6 residual oil,
including oil preheater, filters, pumps, and transport lines. The facility was nominally fired on
residual and distillate fuel oil during workdays and on gas during nights and weekends. The fuel
changeovers at the start and the end of oil firing were done with a minimum of temperature
excursions.
The test section with the light-weight Kaowool refractory was fabricated by the refractory
manufacturer, Thermal Ceramics. The test section was positioned as the center spool in the
down-fired precombustion section (refer to Figure B-l). TTiis position provided the temperature
window of interest of about 1540 °C (2800°F), and also was sufficiently downstream of the burner
to allow oil volatilization.
lrThe subscale refractory tests and the data analyses in this section were conducted by Ravi
Srivastava of Acurex, Research Triangle Park, NC.
88
-------
PRIMARY FUEL
I
^ PRIMARY AIR
SAMPLE
PRECOMBUSTION CHAMBER
RADIAL STAGED AIR
BOILER REBURN FUEL
AXIAL REBURN AIR
PACKAGE BOILER SIMULATOR
f^SII
Figure B-l. EPA package boiler simulator.
89
-------
Instrumentation was as is normally used with the PBS NOx control testing. In addition,
a thermocouple was positioned at the upstream plane of the refractory test section midway
across the combustor flow. This was needed to monitor combustion gas temperatures to detect
if the temperature limit of the material, 1566 °F (2850°F), was exceeded.
B3 RESULTS
Table B-l lists the operating log for the three test phases: quasi-steady, transient, and
failure mode. The appearance of the refractory surface prior to the testing and during various
stages of the tests is shown by the photos of the bore of the test spool on Figure B-2.
During the quasi-steady testing, various equipment malfunctions and scheduled
maintenance necessitated several furnace shut-downs. The cold start-ups following a shut-down
as well as other operational excursions resulted in more thermal transients than were specified
in the test plan. Table B-2 lists the nominal steady-state test conditions during the first test
phase. The transients which actually developed during the course of the quasi-steady testing are
summarized on Table B-3. The NOx levels indicated on the test summaries do not reflect the
potential capabilities of this combustor. This is because in the subscale facility the heat losses
are much higher than in the field, so the combustor temperatures were over 56°C (100°F) lower
than the optimum in the fuel-rich precombustor for a given stoichiometric ratio. These lower
temperatures slow the NOx reduction reactions causing higher flue gas emissions than will be
realized in a full scale combustor. The refractory after the 4-week quasi-steady test period
showed no significant surface cracking or other signs of surface deterioration as shown on
Figure B-2b. The rectangular chip missing from the surface coating at the top of the spool is
thought to be mechanical damage during disassembly of the combustor for inspection.
During the transient testing phase, temperature cool-downs and ramp-ups were created
in the combustor over a 5-day period. A cool-down episode was initiated by stopping the natural
gas firing and purging the combustor with air. This would lower the temperature, Tl, at the
center of the combustor to below 815°C (1500°F). A ramp up condition was then created by
firing at the maximum firing rate that the gas delivery system would allow at a slightly lean
stoichiometry. After 15 minutes of this high fire, the fuel feedrate was reduced and the
stoichiometric ratio was reduced to a fuel-rich condition. This would cause the centerline
temperature, Tl, to level off around 1540 °C (2800°F) within 15 minutes of the start of the ramp-
up. After maintaining a temperature of 1540°C (2800°F) for over 15 minutes, the fuel was shut
off and the air purge started to initiate another cool-down cycle.
Tables B-4 and B-5 show the operating conditions and temperature excursions throughout
the 5 days of the transient testing. Figures B-3 through B-12 illustrate the temperature
variations for the 5-test days. The temperature T2 at the edge of the refractory shows the same
general trends of the gas temperature, Tl, but exhibits lower temperature swings due to the wall
conduction. The appearance of the refractory after transient testing as shown on Figure B-2c
was very similar to the appearance after the quasi-steady tests.
Following the transient testing, a 32 cm3 (2-in3^ sample of each layer of the refractory
was removed for inspection and analysis by the manufacturer. The final test phase to explore
refractory failure limits was then started. The combustor temperatures were raised to levels
beyond those recommended for continuous operation of the refractory. For this series, the
furnace was fired with No. 2 oil since the hardware constraints allowed higher firing rates and
temperatures with oil firing. The combustor was fired with No. 2 oil to maintain the center bore
temperature near 150°C (300°F) for four periods of 8-hours each. The test spool was allowed
to cool and inspected after the first 8-hour test period and then again after the final 8-hour
90
-------
TABLE B-l. DURABILITY TESTING OPERATING LOG
DfeTE
DATE
FUEL START
HUE
{hr 5.)
END
TIME
Ihrs)
1 IKE FIRING
FIRED RATE
(hr s 1 (flfitu/M
02
(1)
-AVERAGE-
CD C02
(pp«! HI
NO
(pp«)
--START/FINISH-
T1 T2
IF) IF)
REMARKS
DfiTt
DATE
FUEL
START
TIKE
Itirs)
END
hue
(hr&J
T inE FIRING
FIRED RATE
(tirsl (NBtu/h)
--START/FINISH-
T1 12
-------
TABLE B-l. (continued)
DATE DATE FUEL START END TINE FIRING AVERAGE STARI/FINISH--
11NE TINE FIREC RATE 02 CD CD2 NO T1 T2
(hrsl (hrs) (hr5) |HBtu/h| II)- |pp«) (1) Ippi) IF). (F)
RENBRKS
J?/O9/0S I2/09/B6 NG 13:00
12/12/86 12/12/B6 13:00 72 9.98E+05 10.7 0 5.3
2300 T/C BURNT «6 LINES COLD flOMDAY BORN 1KB; BACK
2420 T/C BURNT PRESSURE RE6ULAT0R NOT RELIEVING.
CLEANED THE REBULATOR.
12/12/06 12/12/88 16 13:00
12/12/88 12/12/88 15:30 2.5 2.02E»0t 4.5 20 10.1
2400 T/C BURNT OVERTENPERATURE SHUT OFF.
7600 T/C BURNT
12/12/88 12/12/8B 12 16:00
12/12/08 12/12/88 16:15 0.25 2.07E»06 5.3 20 6.4
2660 T/C BURNT
2660 1 It BURNT FIRED ON 12 FUEL OIL.
12/12/B8 12/12/88 NB 16:15
12/13/86 12/13/88 8:30 16.25 9.96E+05 8.8 25 5.2
2200 T/C BURNT
2400 T/C BURNT
12/I3/6E 12/13/68 16 6:30
11:30 3 7.02E+04 3.5 15 12.6
2370 T/C BURNT OVERTENPERATURE SHUT OFF DUE TO tt
2800 T/C BURNT FLOW DECREASE. ATTEMPTS TO FILL <6
RESERVOIR FRO" HOUSE SUPPLY UNSUCCESSFUL
DUE TO HEATERS ON HOUSE SYSTEM INOPERATIVE
12/13/B5 12 /13/68 No 13:00
12'15'B8 12/15/66 12:30 47.5 9.96E»05 10.0 20 6.0
]6CC T/C BURNT UNABLE TO GET AN* 16 FRO* HOUSE SUPPLY
2460 T/C BURNT UNTIL NOON Of 12/15/B8.
12/15/86 12 '15/88 tt 12:45
12/15/06 12/15/86 15:15 2.5 2.02E«06 2.5 50 18.0 120
2480 T/C BURN!
2620 T/C BURNT VERY ERRATIC It FLO*.
12/15/66 12/15/86 >2 15:15
12/15/66 12/15/86 15:30 0.25 2.07E*06
2660 T/C BURNT
2660 T/C BURNT BRIEF FIRING OF 12.
12/15/88 12/15/B8 NS 15:30
12/16/66 12/16/B8 9:00 17.5 9.9Bf»05 12.1 20 4.7 60
2240 T/C BURNT
2600 T/C BURNT IDLING.
12/16/88 12/16/66 It 9:15
12/16/66 12/16/88 12:45 3.5 2.02E+06 2.5 28 13.2 140
2600 T/C BURNT OVERTENPERATURE SHUT OFF PROBSB.Y DUE
2800 T/C BURNT TO FAILING T/C. SHUT DOWN FOR THE
WEEKEND IN THE ABSENCE OF OVERTENP
PROTECTION.
12/19/88 12/19/B6 NG 12:45
12/20/88 12/20/B6 10:00 21.25 9.98E+05 10.0 16 6.5 20
70 T/C BURNT T/C REPAIRED AND FURNACE BROUGHT UP.
2260 T/C BURNT
12/20/88 12/20/66 NS 10:00'
13:00 3 1.87E~04
2260 T/C BURNT NATURAL BAS DATA AQUISITION.
2480 T/C BURNT
12/20/08 12/20/88 t6 13:15
15:15 2 2.02E»06 3.0 20 12.0 140
2400 T/C BURNT T/C FAILED. T/C HIRE ORDERED.
2700 T/C BURNT
0I/03/B9 01/03/89 NG 9:45
01/03/09 01/03/69 11:00 1,25 9.98E*05 10.1 30 9.2 75
70 70 COOLANT OVERHEAT. COOLANT PUNP STARTED.
1960 1750
01/03/89 01/03/69 NB 11:15
01/03/89 01/03/89 14:00 2,75 9.98E»05 9.6 35 9.2 60
1700 1300 T/C PROVIDED 8* NVO FAILED.
2560 2300
01/16/09 01/16/89 NG 10:00
0W17/89 01/17/89 2:00 16 9.9BE»05
0 9.4
70 T/C BURNT LOOSE T/C HIRE CAUSED OVERTENP SHUTDOWN.
2600 T/C BURNT
92
-------
TABLE B-l. (continued)
DATE DATE FUEL STAR! END TIKE FIRING AVERAGE START/F1NISH--
TIBE 11 BE FIRED RATE 0? CD C02 NO 11 12
Ihrs) (hrs) (hrs) (NBtu/h) (II [ppi)' (I! (pp.: (F] (F)
RECIftfiKS
01/17/89
01/17/89
01/17/8?
01/17/8?
NG 10:15
15:00 <.75 9.98E»05 10.9 0 10.0 35
1400 1/C BURN! FURNACE RE-HEATED AFTER SHUTDOWN.
2480 1/C BURNT
01/17/89
01/17/89
01/17/89
01/17/89
NG 15:00
17:00 2 6.I5E»05 10.2 0 10.6 35
2480 T/C BURNT SET UP NED ION I DIE SETTINGS.
2380 1/C BURN!
01/17/89
01/17/B9
01/17/89
01/17/89
NG 17:00
17:30 0.5 l.iOEtOi 8.0 0 11.8 300
2240 1/C BURNT TRIAL HIGH FIRE SETTINGS.
2400 T/C BURNT
01/17/89
01/18/89
01/17/89
01/1B/89
NG 17:30
8:30 15 8.15E+05 7.1 0 12.4 50
2600 T/C BURNT OVERNIGHT IDLING.
2*00 T/C BURNT
01/18/89
01/18/8?
01/18/89
01/18/89
NE 8:30
18:00 8.5 VARIOUS
T/C BURNT TRANSIENT SETTING DETERMINATION,
1/C BURNT
0!1B •' 8c'
01,'19/89
01/18/89
Ci/19/89
NE 18:00
10:05 16 7.10E»05 12.3 35 9.0 30
2800 T/C BURNT OVERNIGHT IDLING.
2400 T/C BURNT
01/19/89
01/19/89
01/19/89
0J/19/B9
NG 10:00
17:15 6.25 VARIOUS
T/C BURNT TRANSIENT TESTING: DAY 1.
01 ,'19/69
01/20/89
01/19/89
01/20/89
NG 17:15
:30 15.25 7.1OE*05 11.7 45 8.8 20
1400 2000 OVERNIGHT IDLING.
2560 2380
Oi/TC/SC
01720/89
01/20/89
01/20/69
NE 8:30
15:00 6.5 VARIOUS
TRANSIENT TESTING: DM 2.
01 ,'20/89
C1/23/B9
01/20/8'
01/23/89
NG 15:00
9:00 66 7.10E+05 5.7 (5 12.0 30
1700 2100 WEEKEND IDLING.
2750 2600
01/23/89
01/2'3/e?
01/23/89
01/23/89
NG 9:00
15:30 6.5 VARIOUS
TRANSIENT TESTING; DAY 3.
01/23/69
01/24/89
01/23/89
01/24/89
NG 15:30
9:00 17.5 7.I0E»05 10.6 BO
25
1200 1800 OVERNIGHT IDLING.
2640 2480
01/24/89
01/24/89
01/24/89
01/24/89
NG 9:00
15:30 6.5 VARIOUS
TRANSIENT TESTING: DAY 4.
01/24/89
01/25/89
01/24/89
01/25/89
NG 15:30
7:45 16.25 7.10E+05 4.5 0
50
1400 2000 0VERNI6HT IDLING.
2500 2320
01/25'e9
01/25/89
01/25/89
01/25/89
NE 7:45
15:15 7.5 VARIOUS
TRANSIENT TESTING: DAY 5.
01/25/89
01/25/89
01/15/89
01/25/B9
NG 15:15
17:30 2.25 1.5BE06 4.5 50
100
2400 2500 HIGH FIRNG
2800 2450
01/25/B9
02/02/B9
01/25/89
02/02/89
NG 17:30
14:00 188.5 7.10EO5
2BC0 - 2450 LONG TERM IDLING. CEHS SNITCHED OFF.
2400 2300 SHUT OFF FOR PHOTOGRAPHING OF TEST SPOOL
93
-------
TABLE B-l. (continued)
DATE DATE FUEL START END TIHE FIRING — AVERAGE START/FIN1SH-
TIPIE II BE FIRED RATE 03 CO CD2 NO T1 T2
(hrs) (hrs) (hrs) (BBlu/h) II) (pp.! ID Ippi) (F) (F)
RfHARK5
02/14/89 02/14/89 NB 17:15
02/15/69 02/15/09
70 70 STAB! UP FOR FAILURE TE5TING.
8:30 15.25 9.98E*05 10.6 10 9.4 300 2560 2640
02/15/89 02/15/89 N6 8:30
02/15/89' 02/15/B9
9:30 1 9.9BE*05 8.4 10 10.7 75
2560 2640 SUITCHED TO IDLE SETTINGS.
2500 2380
02/15/69 02/15/B9 N6 9:30
02/15/09 02/15/89
12:00 2.5 1.72E»06
2500 3380 HIGH FIRE SETTING DETERNINrTlON,
2510 2470
02/15/89 02/15/89 NG 12:00
02/15/89 02/15/89
15:00 3 1.08E»06 7.0 15 11.6 230
2510 2470 ATTEMPT TO ATTAIN 3000 DEGREES WHILE
2600 2650 FIRING ON NATURAL GAS
02/15/89 02/15/89 12 15:15
02/15/89 02/15/89
17:30 2,25 1.96E»06 4.2 27 .14.2 890
2240 2360 12 FUEL OIL SETTING VERIFICATION
2980 2700
02/15/0' 02/15/89 NG 17:30
O:/16/85 02/16/69
9:30 16 9,98E»05 7.4 30 11.5 40
2980 2700 OVERNIGHT IDLING.
2340 2480
02/16/89 02/16/B9 12 9:45
02/16/89 02/16/89
18:00 8-25 VARIOUS
2340 2480 BORE TEHPERATURES HAINTAINEC NEAR 3000.
2980 2580 SHUT OFF FOR, PHOTOGRAPHING Of TEST SPOOL.
02'20,'89 02/20/89 N5 11:00
02/21/89 02/21/89
10:30 23.5 9.90E»O5 8.9 40 10.0. 240
70 70 START UP FOR CONTINUED FAILURE TESTING.
2550 2680
02/11/09 02/21/85 12 10:30
02/21/09 o:/ri/B9
18:30
1.70E+06 7.5 50 13.0 700
2550 2680 FAILURE TESTING. DAY 2.
2996 2800
02/21/89 02/21/69 NG 18:45
02/22/89 02/22/8=
B:45 14 9.98Ef05 6.9 38 11.4 35
2996 2800 OVERNIGHT IDLING.
2470 2540
02/22/8" 02-'22/89 42 9:00
02/22/69 02/22/89
17:00
1.80E+06 7.2 40 13.2 700
2470 2540 FAILURE TESTING. DA* 3.
2967 2800
02/22/6c 02/22/69 NG 17:00
02723/89 02/23/89
10:00 17 9.98E+05 7.5 40 11.3 50
29B7 2800 0VERN1GH1 IDLING.
2430 2220
02/23/89 02/23/B9 12 10:00
02/23/89 02/23/89
18:00 8 1.80E +06 7.2 10 13.1 800
2430 2220 FAILURE TESTING. DA* 4
2996 2830 SHUT OFF FOR PHOTOGRAPHING OF TEST SPOOL.
94
-------
a. Before testing b. After Quasi-steady tests
c. After Transient tests d. After Overtemperature tests
Figure B-2. Refractory response to durability testing.
95
-------
TABLE B-2. STEADY STATE ENDURANCE TESTING (PHASE I)
TEMPERATURE
RANGE, T1
FUEL (F)
TOTAL
HOURS
02
( % )
EMISSIONS
NO
(ppm)
CO
(ppm)
CO 2
( % )
Trace Reference
NG 2200-2300
330
5.3-10.7
5-100
0-50
7-8 . 5
(11-22,23-88)
(11-28,29,30-88)
(12-1,5,9-38)
(12-13,14,15-38)
(12-19,20-83)
(1-16,17,13-39)
(1-19,20-39)
(1-23,24,25-89)
#2 2660
0.5
10.3-10.7
30-50
0-20
4.2-4.8
none
#6 2600-2800
19.5
2.6-4.4
120-160
10-30
12.2-18
(11-23-83)
(12-7,9,12-88)
(12-13,16,20-33)
TEMPERATURE
RANGE, T1
FUEL (F)
HOURS
02
( % )
EMISSIONS
NO CO
(ppm) (PPm)
( % )
Trace Reference
-------
TABLE B-3. TRANSIENT OPERATION OCCURRING DURING PHASE I
TEMPERATURE
EMISSIONS
RAIMGE , T1
D2
NO
CO
C02
FUEL
-------
TABLE B-4. TRANSIENT TESTING OF LIGHTWEIGHT REFRACTORY SPOOL—EMISSIONS
1-19-89
Emissions (at 0% 02)
FR
SRI
SR2
C02
CO
NO
(Btu/h)
(%)
(ppm)
(ppm)
Graph Points
1.03E+06
0 . 98
1 . 23
22 . 61
110
192
2,3
1.63E+06
1. 04
1 . 44
23 . 64
535
591
3,4,5
1. O'SE+06
0 . 99
1 . 59
24 .61
175
273
5,6,7
1.63E+06
.1.04
1. 20
22 . 06
256
549
8,9,10,11
1.08E+06
0 . 98
1 . 23
22 . 04
133
275
11,12,13
1.63E+06
1 . 04
1 . 20
21. 32
193
661
14,15,16,17
1.08E+06
0 . 92
1 . 17
21. 37
114
151
17, 13, 19,2.0,21
1.63E+06
1 . 04
1.20
21 . 97
214
591
22 , 23,24,25
1.0SE+06'
0 . 92
1 . 17
22 . 57
131
256
25,26,27
1.63E+06
1 . 03
1. 20
21 . 83
¦ 135
634
28,29,30,31
1.03E +06
0.92
1 . 17
21 . 66
131
143
31,32,33,34,35
i . 5 3 E + 0 6
1 . 07
1 . 23
22 . 19
151
605
36,37,33,39
1.08E+06
0 . 85
1.10
21 . 31
116
69
39,40,41
98
-------
1-20-89
TABLE B-4. (continued)
Emissions (at 0% 02)
FP
SRI
SR2
C02
CO
NO
(Btu/h)
(%)
(ppm)
(pprri)
Graph Points
1 . 61E+06
1 . 05
1.21
16 . 39
73
657
3,4,5,6
1.08E+06
0 . 35
1 . 10
15. 54
52
63
6,7,3
1.61E+06
1. 05
1.21
16 . 40
78
620
9, 10, 11,12
1.0SE+Q6
0. 85
1 . 10
15 . 61
58
70
12, 13,14
1.61E+06
1. 04
1.21
16.36
67
465
15,16,17,13
1.03E+06
0 . 35
1.10
15 . 57
58
62
13,19,20
1.61E+06
1 . 05
1 . 21
16.34,
71
549
oi on 07 n A
1.03E+06
0 . 85
1 . 10
15. 59
54
66
24,25,26
1 , 61E + 0 6
1 . 04
1. 21
16 . 33
64
339
27,28,29,30
i.asE+oe
0 . 85
1.10
15 . 62
56
64
30,31,32
1.61E+0S
1 . 05
1 . 21
16 . 34
67
470
33,34,35,36
1.08E+06
0 . 85
1 . 10
15.63
54
7 0
36,37,33
99
-------
1-23-89
TABLE B-4. (continued)
Emissions (at 0% 02)
FF
(Btu/h.)
SP1
SF
2
C02
<%)
CO
(pprrj)
NO
(pprrj)
Graph Points
1.03E+06
0 . 83
1 .
13
NA
36
91
6,7,8
1.54E+06
1 . 11
1.
28
NA
37
401
9,10,11,12
1.03E+06
0.93
1.
18
NA
36
138
12,13,14
1.54E+06
1.11
1.
23
NA
49
547
15,16,17,18
1.03E+06
0 . 95
1 .
19
NA
45
138
18, 19,20,21
1.54E+06
1.10
1.
23
NA
54
592
22,23,24,25
1.03E+06
0 . 96
1 .
20
NA
52
173
25 , 26,27,28
I.5 4E+06
1.11
X .
23
NA
60
536
29,30,31,32
1.GoE+06
0 . 92
1.
17
NA
57
130
32,33,34
1.54E+06
1.10
1.
23
NA
39
517
35,36,37,33
1 . 0 3E+CJ6
0 . 95
1.
19
NA
111
149
38,39,40
100
-------
[-24-89
TABLE B-4. (continued)
FF
(Btu/h)
SRI
SF2
Ernies
CO 2
(%)
ions (at
CO
(ppm)
0% 02)
NO
(ppm)
Graph Points
1 . 56E+06
1 .09
1. 26
NA
103
583
3,4,5,6
1.03E+06
0 . 93
1 . 23
' NA
94
214
6,7,3,9
1.56E+06
1 . 09
1 . 26
NA
105
623
10,11,12,13
1.08E+06
0. 93
1. 22
NA
104
273
13,14,15
1.56E+06
1. 09
1. 26
NA
110
687
16,17,18,19
1.08E+06
0. 87
1 . 11
NA
98
96
19,20,21,22
1.56E+06
1. 09
1 . 26
NA
118
615
23,24,25,26
1 . 08E+06
0 .91
1 . 16
NA
101
133
26,27 ,28,29
1.56E+Q6
1 . 09
1 . 26
NA
115
580
30,31,32,33
1 . 08E+06
0 .91
1 . 16
NA
101
137
33,34,35
1.56E+06
1. 09
1 .26
NA
118
636
36,37,38,39
1.03E+06
0 . 90
1.15
NA
1 0 0
126
39,40,41
101
-------
1-25-89
TABLE B-4. (continued)
FP
(Btu/h)
SRI
SR2
Emissions (at
C02 CO
(%) (ppm)
0% 02)
NO
(ppm)
Graph Points
1.58E+06
1 . 08
1 . 25
NA
111
554
3,4,5,6
1.08E+06
0. 87
1. 12
NA
72
96
11,12,13
1.53E+06
1 . 08
1 . 25
NA
82
545
14,15,16,17
1.08E+06
0.90
1. 14
NA
75
118
17,18,19
1.58E+06
1 . 07
1 .24
NA
90
554
20,21,22,23
1.08E+06
0 . 39
1. 14
NA
73
119
31,32,33
1 .-53E + 06
1 . 07
1 . 24
NA
33
543
34,35,36,37
1.03E+06
0 . 39
1 . 14
NA
3 3
119
37,33,39
1 .¦58E+06
1 . 0!6
1. 23
NA
72
286
40,41,42,43,44,45
1.03E+06
0 . 39
1 . 14
NA
76
113
45,46,47
1.58E+06
1 . 06
1 . 23
NA
63
291
48,49,50,51
1.0SE+06
0 . 33
1 . 13
NA
33
115
51,52,53
102
-------
TABLE B-5. TRANSIENT TESTING OF LIGHTWEIGHT REFRACTORY SPOOL—TEMPERATURES
1-19-B9 ; 1-20-89 : 1-23-89 1-24-89 ; 1-25-89
Pt. lime [1 T 2 : Time T1 T2 ITirr.e 11 T2 ITirr.e Tl T2 ; Time T1 12
# ( it, i r, ) (F) (F ) ! Imin) (F) (F) ! (min) (F) (F) : (mn) (F) (F) : (min) (F) (F)
0
2340
0
2560
2300
0
2740
2580
0
2680
2520
0
254 0
2370
r>
5
234 0
7.5
2560
2380
35
2740
2580
35
2680
2520
25
2540
2370
3
77
2400
48
1320
1970
48
1680
2180
48
1 560
2040
38
1600
194 0
4
78
2410
49
2300
2140
49
2300
2400
49
2240
24 10
39
2140
22,4 0
5
95
2515
55
2440
2360
55
2400
2460
55
2320
2460
45
2260
2400
6
97
2760
65
2520
2500
65
2440
2490
65
2380
2540
55
2320
2400
7
135
2000
66
2810
2510
66
2790
2570
66
2760
2440
56
2600
2400
6
1 4 B
1290
95
2010
2520
95
2B10
2610
75
2800
2490j
65
2760
¦ 2440
9
150
2220
108
1360
1980
108
1440
2040
95
2020
2520
100
2700
2480
10
155
2340
2320
110
2340
2330
no
2240
2320
108
1340
1940
101
2410
2560
1
165
2440
2420
115
2440
2420
115
2370
2500
110
2220
2340
115
2420
2610
12
170
27B0'
2460
125
2500
2470
125
2430
2540
115
2340
2460
116
2800
2520
13
205
2820
2510
126
2020
2500
126
2800
2540
125
2420
2560
145
2000
2520
14
210
1370
20 J 0
155
2020
2520
155
2820
2590
126
2700
2500
150
1440
1990
15.
220
2360
2350
160
1270
1940
168
1380
2000
155
2020
2530
160
2200
2320
. 16
225
2380
2370
170
2240
2100
170
2080
22B0
168
1440
2000
165
2320
2460
17
235
2400
2 4 50
175
2440
2430
175
2350
2440
170
2200
2300
175
23B0
2540
IB
237
2590
2460
185
2490
2460
105
247.0
2540
175
2390
2510
177
2000
2480
19
245
2610
2490
187
2810
24 BO
1B7
2740
2540
185
2430
2560
205
2000
2520
20
2 4 fa
2010
2510
215
2010
2510
195
2000
2580
187
2780
2490
210
1470
2000
21
265
2810
2540
226
1340
1960
21 5
2810
2630
195
2820
2530
220
2220
2360
22
276
1 380
2020
230
2240
2220
22B
14 00
2060
215
2820
2530
225
2320
2460
23
2B0
2300
2280
235
2400
2390
230
2240
2345
228
1440
1980
235
2300
2560
24
205
2400
2390
245
2500
2400
235
2380
2470
230
2280
2370
236
2600
2470
2 5
295
2490
2470
246
2020
2490
245
2440
2540
235
2380
2520
250
2730
2480
26
290
2B00
2500
275
2020
2510
246
2740
2540
245
2440
2560
251
2390
2580
27
325
2820
2540
288
1380
1980
255
2800
2580
246
2780
2520
265
2410
2600
20
330'
1360
2000
290
2340
2240
275
2810
2620
255
2020
2540
266
2740
2530
29
340
2380
2360
295
2420
2420
28B
1360
2020
275
2820
2540
200
2740
2520
30
34 5
24 40
24 30
305
2500
2500
290
2220
234 0
2BB
1420
1980
281
2420
2600
31
355
2520
2 500
307
2820
24BO
295
23fe0
2460
290
2260
2360
300
2450
2650
31'
3 57
2650
251 0
335
2020
24 90
305
2460
2520
295
2400
2500
301
2000
2570
33
7.6 3
2600
2 530
348
1360
1980
307
2800
2520
305
2440
2570
325
2800
2570
34
life 4
2020
2540
350
2240
2260
335
2820
2630
307
2000
2500
330
1640
2080
35
385
2020
2550'
355
2440
2440
348
1 3B0
2020
335
2010
2540
340
2240
2380
36
390
1300'
2000
365
2520
2520
350
2260
234 0
348
1440
2000
345
24 00
2540
37
4 00
2420
'2260
366
2020
2480
355
2400
2500
350
2240
2380
355
24 50
2620
30
405
2560
2410
395
2020
2520
365
2460
2540
355
2360
2500
356
2BOO
2540
39
415
2660
2 500
408
1740
2160
366
2 B 0 0
2540
36 5
2400
2560
385
2BOO
2540
40
416
2B20
2560
410
2500'
2330
395
2820
2640
366
2790
2490
398
1590
2060
41
445
2820
25Bk>
415
2580
24 00
400
1720
1 B60
395
2820
2540
400
2160
2300
42
4 50
14 40
2080
420
2 590
24 20
4 1 U
2 4 4 0
2180
408
14B0
2040 '
405
2240
2400
4 3
4t-0
24 30
2 260
460
2550
2420
4 1 5
2580
2340
4 J 0
2300
2440
410
2250
2410
44
A ft 5
2540
2330
500
2550
2420
440
2660
2470
415
2400
2540
411
2340
2500
4 5
4 75
2620
2400
470
2680
2510
4 30
2440
2560
425
24 6 0
2610
4t
413 5
2640
2440
500
2680
2510
500
24 4 0
2560
426
2BOO
2520
47
i 500
264 0
2440
445
2800
2530
48
4 58
1620
2060
49
460
2300
2400
50
465
24 20
254 0
51
475
2500
:'6?0
5?
476
28 u •
2540
53
500
2810
2540
103
-------
ST
I
f ~
X z
w e
M
t £
L v
&
E
300
2.90 -
2.80 -
2.70
2.60 -
2.50 -
2.40 -
2 JO
2.20 -
2 10 -
2 J>0 -
\*0 -
1 30
1.70 -
1.60 -
1.60 -
1.40 -
1 -30 -
1.20 -
1.10 -
1 DO
1%
1
1
200
Trr* (mJnutoa)
4-00
Figure B-3. Transient bore temperatures (Tl)—1-19-89.
1-19-09
k
I
11
I
I
Figure B-4. Transient inner spool temperatures (T2)—1-19-89.
104
-------
i-20-ee
2.00
.
2.90
2.BO
-
2.70
-
2,60
-
2-50
-
b.
2.*0
-
1
2.30
-
f ^
9 «
2.20
-
• r
© c
2.10
-
A ¦
2.00
-
3 0
% e
W V
1.90
1 80
1 .70
-
1.60
-
1 .£0
-
1 .*0
-
1 .30
-
1 .2D
-
1 -10
-
1 .00
—
/
'fr-
f
19-—®
26—ft6
vT
f
3f—¥
/
3?—
f
¦*3r-
I
15
200
Time (minute*)
400
Figure B-5. Transient bore temperatures (Tl)—1-20-89.
Figure B-6. Transient inner spool temperatures (T2)—:
105
1-20-89.
-------
1-23-69
!
3.00
2.90 -
2-80
2,70 -
2 60 -
2.60 -
2.40 -
2 JO -
2.20
2.10
2-00 -
1.90
1 BO -
1.70 -
1.60
1 AO -
1 ,40 -
1.30 -
1.20 -
1 .10' -
1 .00
r
1|5-
/
n
,rr aTT t
1 5
,1
f
1
200
Time (minutes)
400
Figure B-7. Transient bore temperatures (Tl)—1-23-89.
1-23-69
t
9 *
• T
V C
c
II
6,
E
3.00
2.90 -
2.80 -
2.70 -
2.60
2.50 -
2 40 -
2.30 -
2,20 -
2,10 -
2,00 -
1,90 -
1.00 -
1.70 -
1.60 -
1.60 -
1 .40 -
1.30 -
1.20 -
1,10 -
1.00
-r
200
Time (minutes)
400
Figure B-8. Transient inner spool temperatures (T2)—1-23-89.
106
-------
1-24-49
3.00
2.90
2.60 -
2 70 -
2 ,60 -
2.50 -
2.40 -
2.30
2.20 -
2.10 -
2.00 -
1 $0 -
1 ao -
1 .70 -
1 .60 -
1.50
1 .40
1.30 -
1 .20 -
1 .10 -
1 .00
/
r-*f aMF a?®-5?
f
ib
f
ite
f
f
1
f
200
Time (mirmtes)
400
Figure B-9. Transient bore temperatures (Tl)—1-24-89.
Figure B-10. Transient inner spool temperatures (T2)—1-24-89.
107
-------
I
f
» •
• V
r c
^ c
ij
o P
k ¦w
£
E
3.00
2.90
2.80 -
2-70 -
2.60 -
2.50 -
240 -
2 JO -
2.20 -
2-10 -
2.00 -
1 jo -
1 JO -
1,70 -
1.60 -
1.50 -
1 .40 -
1.30 -
1.20 -
1 .10 -
1 .00
1-25-09
1J—V
/
f
n *
3i—SJ
3B—S
f
n
,7 fie—s 5
I
200
Trrre (rrvrvute#)
400
Figure B-ll. Transient bore temperatures (Tl)—1-25-89.
1-25-69
3.00 -i
2.90 -
2,80 -
2.70 -
2.60 -
2.50 -
L
2.40 -
s
2,30 -
c ^
2,20 -
® t
V c
2.10 "
P 5
2.00 -
re
1 JO -
to
1 JO -
A.
£
1 .70 -
c
1 ,60 -
1 £0 -
1.40 -
1 .30 -
1-20 -
1.10 -
1.00 -
Figure B-12. Transient inner spool temperatures (T2)—1-25-89.
108
-------
test. Tables B-6 and B-7 summarize the temperature and emissions data during the failure mode
overtemperature testing. The plots of temperatures are shown on Figures B-13 through B-22.
The refractory condition at the conclusion of the overtemperature testing is shown on photo
B-2d. The primary effects of excursions above 1566°C (2850°F) appeared to be deterioration
of the Unikote surface coating. This coating was largely intact at the start of the failure tests,but
was approximately 25 percent gone after the four 8-hour tests. The manufacturer indicated
the primary function of the coating is for added structural integrity during installation. At this
stage, the uncured refractory is soft and pliable. After the initial firing and curing, the pyro-
block becomes hard and the coating has little additional value. Apart from the loss of the
Unikote, the surface showed no other significant cracking or other signs of deterioration.
109
-------
TABLE B-6. FAILURE TESTING OF LIGHTWEIGHT REFRACTORY SPOOL—EMISSIONS
Dgte: 2-15-Bc'
Fu >-1 f-R , SRI
(Bt n 'h )
Emissions (at 07. 02)
SR2 C02 CO NO
("/.) (ppm) (ppm) Graph Point;
NG
NG
NG
9.93E+05 1.06 1.71 18.98
9.98E+05 0.81 1.72 17.83
9 . 93F. + 05 1 . Ofc 1.71 1G. 98
i."2EH0i 0.79 1.23 16.61
1 . 72'E-i 06 0.99 1.23 17.05
1.72E+06 0.93 1.17 16.43
l.~2Ei06 0.91 1.15 16.26
1 . '.'Lu * 1.11 1 ¦ 5u 1 / . 4r.'
I."u.^i06 1.07 1.34 20.15
20 606 0,1
17 117 2,3
30 121 4,5
21 618 6,7
20 641 6,7
20 457 6,7
19 397 6,7
23 345 8,9
33 1277 10,ll,i:
Emissions (at 0"/. 02)
PR SRI GR2 C02 'CO NO
(Ltu.'h) (7) (ppm) (ppm) Graph Points
NG r. "'32 0.8! 1.37 17.76 62 46 0,1
*2 2.25E+06 0.94 1.18 18.20 53 432 2,3,4,5,6
1.05 1.31 19.38 67 983 7,8
*2 2.0T-:-06 1.02 1.27 19.30 65 809 9,10,11
*2 J. 07 0 06 1.13 1.42 20.26 74 1361 11,12
1 .020 06 1.16 1.45 20.70 76 1293 12,13
*12 1.55Z-t06 1.36 1.70 22.09 B1 778 14,15,16
(continued)
110
-------
TABLE B-6. (continued)
Date
F i_l£ 1
2-21-89
FR
(Btu/h)
SRI
SR2
Emissions (at
C02 CD
(V.) , (ppm)
07. 02
NO
(ppm)
)
Graph Points
NG
9.9BE+05
1 . 06
1.71
17. 36
69
417
0, 1,2
NG
9.9BEh05
0. so
1. 45
17. 11
70
544
2,3,4
*2
1.67E+06
1 . 26
1 . 57
20. 52
D1
BBS
5,6,7
#2
1 . 77IH 06
J ***^
1.52
O (") O "7
73
1034
7,8,9
#2
1. . 79E + 06
i. ie
1. 47
20. 10
75
1230
9,10,11,12,13,14,15,16,17
442
1.73Ei06
1. 22
1. 52
20. 23
77
12E?B
17, IB
D 51 e:
Fue;
i—.n n n
FR
(E t u / h i
SRI
SR2 '
Emissions (at
C02 CO
(y.) (p p ffi)
07. 02
NO
(ppm)
Graph F'oints
t\io
9.9BE+05
0. 80
1 . 35
16. 98
57
CT o
0, 1
#2
1 . 76E-1-06
* 4
1.^1
1 . 50
19. 7B
61
913
2,3,4,5,6
#2
1 . 66E+06
1 . 29
1. 60
20. 35
65
96='
6,7
4+2
1 . 7 6 r-1-06
1 . 21
1. 50
19. 93
61
1065
7,8
TT .u-
1 . OAE-i' 06
1.16
1. 44
19. 69
C ri
UU
1196
B. 9
442
1.25 2'i 06
1 . 5 G
1 . 47
19. 62
c r-i
"?
1 9
9,10
442
1 . 7'7E i 06
1 . 20
1 . 49
20. 09
61
1309
10, 11
442
1.16
1 . 44
19. 83
59
1351
11,12
442
1.75l!06
1 . 22
1.51
20. 30
62
1307
12,13,14
Tr
5 . 'JOE i 06
1 J
1 . 4 3
20. 24
60
1345
14, 15
—»
1 . 7..X-I 06
1.25
1 . 50
20. 53
62
1307
15,16,17
(continued)
111
-------
TABLE B-6. (continued)
Date:
Fuel
: 2-23-39
FR
(B t u / h )
SRI
SR2
Emissions (at
C02 CO
('/.) (ppm)
OV. 02
NO
(ppm)
>
Graph F'oints
NC
9. 9RE+05
0. £31
1 . 36
17. 53
62
78
0, 1
#2
1 .S4E+06
1.15
1. 43
19. SO
11
870
2,3,4
#2
1.92E+06
1.10
1. 37
19. 42
9
1093
4,5,6,7
#2
3 . £3 1 E + U6
1.17
1. 46
19. 79
9
1269
8,9
#2
1. 73E-H 06
^ 1
u i
to 1
1
1. 52
19. 91
12
1307
9, 10
ft
1 . 76E-i 06
1 . 20
1 . 49
19. 93
IE
1380
11,12
#2
1 . C 3 E +06
1.17
1 . 46
19. 96
27
13E5
12, 13, 14, 15, 16
(continued)
TABLE B-7. FAILURE TESTING OF LIGHTWEIGHT REFRACTORY SPOOI^-TEMPERATURES
Temperatures
Pt.
«
Tims
(hrs
2-15-
Tl
(F)
B9
T2
(F)
1 Ti#e
! (hrs)
2-16-89
T1 T2
(F) (F1
! Time
! (hrs)
2-21-
T1
(F)
39
T2
(F)
Tiee
(hrs)
2-22-
T1
(F)
39
T2
(F)
Tite
(hrs)
2-23-
T1
(F)
39
T2
(F)
0
0.00
2560
2640
0.00
2340
2 4 BO
0.00
2550
2680
0.00
2470
2540
0.00
2430
2220
1
0.50
2560
2640
0.75
2340
24B0
0.50
2550
2680
0.67
2470
2540
0.17
2430
2220
2
0.52
2680
2660
0.77
2800
2580
1.08
2380
2600
0.75
2220
2340
0.25
2820
2620
0
1.33
2500
2380
1.25.
2910
2790
1.13
2360
2660
0.83
2600
2500
1.00
2975
27B0
4
1.35
2300
2400
1.50
2950
28(0
1.50
2360
2660
1.00
2800
2630
1.33
2988
2790
c
J
i.70
2440
2490
1.52
2990
2800
1.53
.2200
2320
1.25
2882
2660
3.08
2970
2820
K
1.75
2380
2560
2.00
3000
2810
1.58
2680
2550
1.75
2910
2700
3.17
3003
2820
f
3.92
2510
2670
2.02
3000
2790
1.75
2871
2620
2.50
2859
2660
3.50
3014
2830
6
3.93.
*JC\'
2640
4.00
3040
2840
2.83
2878
2630
3.00
2925
2720
3.53
2992
2810
9
7.00'
2600
2650
4.25
2500
2550
3.75
293(!
2670
3.50
2985
2780
5.08
3009
2820
. A
7. o:
224,: i
23e0
<.33
3004
27 40
4.00
2970
2750
5.33
3021
2810
5.67
2956
2810
j i
* ci'"i
2920
26«
4.50
3019
2790
5.00
2976.
2770
6.25
3003
2760
5.7
2989
2810
'•T
9,5'
29?')
27'X'
5.75
3112
2790
6.00
2989
2790
6.50
3020
2810
6.83
2975
2810
i 7
7.6?
3127
2790
6.50
2996
2800
7.00
2977
2790
7.00
2995
2820
,4
7.75
3000
2660
7.00
3000
2810
8.00
2992
2790
7.50
3010
2830
C
e. oo
2975
2640
7.50
3002
2E20
6.25
3012
2820
B.OO
2993
2B30
t
9.00
29 BO
2530
6.00
3005
2820
B. 75
2986
2800
8.17
2996
2830
1 <
B. 50
3008
2820
9.00
2967
2800
Z
9.50
2996
2800
112
-------
2-16-89
it
c
a
£
2.00
1.60 -
1 60 -
1 .40 -
1.20 -
1 0G
—I 1 I
4 6
Time (Hours)
10
Figure B-13. Bore temperatures (Tl)—2-15-89.
2-1 5-89
L 'w
a
£
3,00
2.90 -
2,60 -
2,70 -
2 60 -
2,50 -
2 40 -
2.30 -
2,20 -
2.10 ~
2.00 -
1 .90 -
1.60
1 .70 -
1 .60 -
1.50 -
1 .40 -
1.30 -
1 .20 -
1 .10 -
1 .00 -¦
10
Figure B-14. Inner spool temperatures (T2)—2-15-89.
113
-------
2-16-89
! ~
9 f!
• V
X c
Time (Hours)
Figure B-15. Bore temperatures (Tl)—2-16-89.
2-16-69
3,00 -|
2.93' -
1.50 -
1 .40 -
1 .30 -
1 .20 -
1 .1 D -
1 -00 -I 1 1 1 1 1 1 1 1
0 2 4 6 8
Tim*
Figure B-16. Inner spool temperatures (T2)—2-16-89.
114
-------
2-21-69
Tirr* (Hour®)
Figure B-17. Bore temperatures (Tl)—2-21-89.
2-21—89
3.00 -|
2 90 -
1 50 -
1 .40 -
1 JO -
1 .20 -
1 ie -
1 .00 | I | I I I I til
0 2 4 6 6 10
T«me
Figure B-18. Inner spool temperatures (T2)—2-21-89.
115
-------
2-22-89
Time (Hour*)
Figure B-19. Bore temperatures (Tl)—2-22-89*
2-22-09
3 00 —
2.90 "
2.60 -
^ 13 M*5 W
2.70 -
2 60 J
2.50 -
1/
r 2,40 -
u
I 2,30 -
4
i? 2 20 J
1 c 2.10-
2.00-
| | 1.90 -
1 so -
g 1 70 -
* 1 .60 -
1.SD -
1 .40 -
1 .30 -
1.20 -
1.10 -
1 .00 -
i i i i i i i i
0 2 4 6 6
Time (Hours)
Figure B-20. Inner spool temperatures (T2)—2-22-89.
116
-------
3.00
2,eo
2.60
o f»
x c 2.20
^ o
11
s I 2.00
0 P
I.
a 1.80
t
1 -60
1 40
1.20
1 .00
Figure B-21. Bore temperatures (Tl)—2-23-89.
2-23-69
Time (Hours)
117
-------
Figure B-22. Inner spool temperatures (T2)—2-23-89.
118
-------
APPENDIX C
DESIGN DRAWINGS
119
-------
120
-------
121
-------
122
-------
REVISIONS
ZOW£
ITS
DESCRIPTION
DATE
APPflOVEO
A
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127
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128
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REVISIONS
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132
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REVISIONS
ZONE
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B
AX>OEP -c"i IH FORMAT Iftlv/
3-1--&9
NOTES:
I. MATERIALS^
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