oofeoeeofc
SYSTEMS EVALUATION OF REFUSE
AS A LOW SULFUR FUEL
A FINAL REPORT TO THE
ENVIRONMENTAL PROTECTION AGENCY
VOLUME II
REPORT NO. F-1295
NOVEMBER 1971
FOSTER WHEELER CORPORATION
Cottrell Environmental Systems
A Division of Research-Cottrell
-------
',/
SYSTEMS EVALUATION OF REFUSE
AS A LOW SULFUR ,FUEL
VOLUME II - APPENDICES
A Report to
ENVIRONMENTAL PROTECTION AGENCY
CONTRACT CPA 22-69-22
AUTHORS
For Envirogenics Company
R. M. Roberts
S. T. Braunheirn
R. C. Hanson
S. B. Kilner
For Foster Wheeler Corporation:
R. E. Sommerlad
J. D. Shenker
R. W. Bryers
-'
,
For Cottrell Environmental Systems. Inc.:
A. P. Konopka
J. McKenna
November 1971
; ~
-------
TABLE OF CONTENTS
VOLUME II
APPENDIX A - WASTAGE AND FOULING
1.
II.
III.
LITERATURE SURVEY. . . . . . . . . . . . . . . . . . . .
A. INTRODU CTION . . . . . . . . . . . . . . . . . . . . .
B. OPERA TING CONDITIONS. . . . . . . . . . . . . . .
C. INIT IAL REMEDIES. . . . . . . . . . . . . . . . . .
D. THEORY........................
1. Corrosion by Reducing Atmospheres. . . . . .
2. Corrosion by Chloride Compounds. . . . . . .
3. Corrosion by Sulfur Compounds. . . . . . . . .
4. Experiences with PbO . . . . . . . . . . . . . .
E. LABORATORY INVESTIGATIONS. . . . . . . . . . .
EXPERIMENTAL. . . . . . . . . . . . . . . . . . . . . . .
A. DISCUSSION......................
B. CORROSION TESTS . . . .
. . . ,. . . . . . . . . . .
REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . .
APPENDIX B - STATE OF THE ART SURVEY
I.
II.
III.
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . .
SUMMARY AND CONCLUSIONS. . . . . . . . . . . . . . .
STEAM GENERATORS. . . . . . . . . . . . . . . . . . . .
A. HISTORY AND TECHNOLOGY. . . . . . . . . . . . .
1.
Historical Development. . . . . . . . . . . . .
" a. Fuels....................
b.
Cycle Efficiency Improvements. . . . . .
Feedwater Treatment. . . . . . . . . . .
Circuitry Evolution. . . . . . . . . . . .
c.
d.
e.
Pres surized Combustion
. . . . . . . . .
f.
g.
h.
Combustion of Crushed Coal
. . . . . . .
Quick-Starting Techniques
. . . . . . . .
Welded Panel- Walls. . . . . . . . . . . .
1.
Excursion into the High Pressure Domain
11
Page
A-I
A-I
A-I
A-?
A-8
A-8
A-9
A-IO
A-16
A-I?
A-20
A-20
A-26
A-28
B-1
B-1
B-3
B-3
B-3
B-4
B-4
B-6
B-6
B-6
B-6
B-?
B-?
B-1
-------
IV.
TABLE OF CONTENTS - Continued
2.
Steam Gen~rator Design. . . . . .
. . . . . . .
a.
Basic Circulation Effects
. . . . .
. . . .
3.
b. Typical Design Characteristics. . . . . .
. c. Fuel Firing. . . . . . . . . . . . . . . .
Cost and Performance Data for Representative
Designs. . . . . . . . . . . . . . . . . . . . . .
a. Characteristics of Ten Selected Steam
Generators. . . . . . . . . . . . . . . .
4.
b. Economic Analysis. . . . . . . . . . . .
Power Generation with Special Fuels. . . . . .
a. Anthracite.................
b.
Lignite. . . . . .
Peat. . . . . . .
. . . . . . . . .
. . . .
c.
. . . . .
. . . . . . . .
d.
Wood Wastes and Waste Liquor. . . . . .
5.
e. Bagasse..................
Applications for Refuse-Firing. . . . . . . . .
a. Steam Cycles. . . . . . . . . . . . . . .
b. Firing Methods. . . . . . . . . . . . . .
c. Power Output Fluctuations. . . . . . . .
AIR POLLUTION CONTROL. . . . . . . . . . . . .
A. NATURE OF EMISSIONS. . . . . . . . . . . .
. . . .
. . . .
l.
2.
Gross Products of Combustion
Particulate Emis sions . .
. . . . . .
. . . . .
. . . .
. . . . . .
a.
Particulate Levels
. . . .
. . . . . . . .
b.
Physical Properties
. . . . . .
. . . . . .
3.
Gaseous Emis sions
. . . . .
. . . .
. . . . . .
a.
Sulfur Oxides
. . . . . . .
. . . .
. . . .
b.
Nitrogen Oxides
Hydrocarbons.
. . . . .
. . . . . . . . . . . . . .
c.
. . . . . . . . .
d.
Carbon Monoxide
. . . . . . . . .
. . . .
e.
Gaseous Emission Summary
. . . . . . .
iii
Page
B-ll
B-ll
B-22
B-31
B-37
B-37
B-49
B-63
B-63
B-69.
B-69
B-69
B-76
B-76
B-76
B-78
B-81
B-81
B-81
B-81
B-82
B-82
B-86
B-91
B-94
B-96
B-96
B-96
B-99
-------
B.
TABLE OF CONTENTS - Continued
EMISSION CONTROL TECHNIQUES. . . . . . . . . .
1. Particulate-Emission Control Devices. . . . .
a.
Mechanical Collectors
. . . . . . . . . .
b. Nitrogen Oxides Control. . . . . . . . .
3. Forecast of Air Quality Standards. . . . . . .
EXPERIENCE WITH REFUSE-FIRED STEAM GENERATORS -
SELECTED GERMAN PLANTS. . . . . . . . . . . . . . .
A. INTRODUCTION....................
B. DESCRIPTION OF GERMAN PLANTS. . . . . . . . .
1. Munich North, Block I. . . . . . . . . . . . . .
2. Munich North, Block II . . . . . . . . . . . . .
3. DUsseldorf....................
4. Stuttgart.....................
DATA ANALYSIS - TECHNIQUES AND OBJECTIVES
TtTV PERFORMANCE TESTS. . . . . . . . . . . . .
V.
C.
D.
E.
F.
b.
Wet Scrubbers.
. . . .
..........
c.
Fabric Filters. .
. . . . . . .
. . . . . .
2.
d. Electrostatic Precipitators. . . . . . . .
Gaseous-Emission Control Devices. . . . . . .
a.
Sulfur Oxide Control
. . . . .
. . . . . .
1. Test Procedures. . . . . . . . . . . . . . . . .
2. Results......................
EMISSION CONTROL (ELECTROSTATIC PRECIPI-
TATOR) EQUIPMENT. . . . . . . . . . . . . . . . .
1. Performance Characteristics. . . . . . . . . .
2. Design Factors. . . . . . . . . . . . . . . . .
3. Performance Guarantees. . . . . . . . . . . .
TtJV DUST COLLECTOR TESTS. . . . . . . . . . .
1.' Particulate Emissions. . . . . . . . . . . . . .
a.
Concentra tions
. . . .
. . . . . . . . . .
b.
Fly-Ash Sizing and Combustibles. . . . .
Ash Resistivity. . . . . . . . . . . . . .
c.
2.
Gaseous Emissions
. . . . . . .
. . . . . . . .
lV
Page
B-99
B-99
B-99
B-101
B-104
B-104
B-108
B- 1 08
B-110
B-115
B-1l6
B-1l6
B-1l6
B-116
B-118
B-118
B-121
B-124
B-125
B-125
B-129
B-134
B-134
B-135
B-138
B-139
B.,.139
B-139
B-142
B - 144
B - 144
-------
VI.
TABLE OF CONTENTS - Continued
G.
EUROPEAN FIELD TRIP. . . . . . . . . . . . . . . .
1. Scope of Activities. . . . . . . . . . . . . . . .
2. Other Refuse-Fired Plants Visited. . . . . . .
a.
b.
c.
d.
e.
f.
g.
REFERENCES.
Essen-Karnap Plant. . . . . . . . . . . .
Berlin-Ruh1eben Plant. . . . . . . . . . .
Munich-South Plant
. . . . . .
. . . . . .
Mannheim Plant
..............
Frankfurt am Main Plant
.........
Issy-1es -Moulineaux Plant. . . . . . . . .
I vry Plant. . . . . . . . . . . . . . . . .
. . . . . . .
.................
APPENDIX C - COST MODEL
I.
II.
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . .
COMBINED FIRING PLANT MODEL. . . . . . . . . . . . .
A. CAPITAL COSTS. . . . . . . . . . . . . . . . . . . .
1. Land and Land Rights. . . . . . . . . . . . . .
2. Structures and Improvements. . . . . . . . . .
3. Boiler Plant Equipment. . . . . . . . . . . . .
a. Case 1 - Separate Furnaces, Blended Flue
Gas. . . . . . . . . . . . . . . . . . . . .
b.
c.
d.
e.
f.
g.
h.
1.
J.
Case 2 - Combined Furnace. . . . . . . .
Case 3 - Separately Fired Economizer. .
Case 4 - Separate Fos sil Fuel Superheater
(Saturated Steam from Refuse-Fired Boiler)
Case 5 - Separate Fossil Fuel Superheater
(Partial Superheat from Refuse-Fired
Boiler) . . . . . . . . . . . . . . '.' . . .
Case 6 - Suspension Fired Steam Generator
Case 7 - Spreader Stoker
Case 8 - Slagging Furnace
. . . .
. . . . .
. . . . .
. . . .
Case 9 - Combined-Fired Arch Furnace
Case 10 - Refuse-Fired Arch Furnace and
Separate Coal-Fired Superheater. . . . .
v
Page
B-l45
B-145
B-145
B-145
B-l49
B-150
B-151
B-152
B-152
B-153
B-154
C-l
C-l
C-l
C-l
C-3
C-3
C-15
C-15
C-16
C-16
C-16
C-16
C-17
C-17
C-17
C-17
-------
III.
IV.
TABLE OF CONTENTS - Continued
4.
5.
6.
7.
Auxiliary Boiler Equipment. . . . . . . . . . .
Turbine-Generator Equipment. . . . . . . . .
Accessory Electrical Equipment. . . . . . . .
Miscellaneous Power Plant Equipment. . . . .
Air Pollution Control Equipment. . . . . . . .
a. Electrostatic Precipitator. . . . . . . .
b. Wet Scrubber. . . . . . . . . . . . . . .
Waste Handling Equipment. . . . . . . . . . .
a. Weigh and Receiving Statfons . . . . . . .
b. Shredding Equipment. . . . . . . . . . .
8.
9.
10. Engineering and Construction Supervision. . .
ANNUAL CAPITAL COSTS. . . . . . . . . . . . . .
1. Amortization..................
2. Federal Taxes. . . . . . . . . . . . . . . ,. . .
3. Insurance and State and Local Taxes. . . . . .
OPERATION AND MAINTENANCE. . . . . . . . . .
1. Basic 0 & M Costs. . . . . . . . . . . . . . .
2. Shredding 0 & M Costs. . . . . . . . . . . . .
3. Air Pollution Control 0 & M Costs. . . . . . .
4. Residue Disposal Costs. . . . . . . . . . . . .
D. POWER GENERATION CREDIT. . . . . . . . . . . .
E. NET SOLID WASTE DISPOSAL CHARGE. . . . . . .
TRANSPORTATION COST MODEL. . . . . . . . . . . . .
REFERENCES. . . . . . . . . . . . . . . . . . . . . . . .
B.
C.
APPENDIX D - BIBLIOGRAPHY
I.
II.
III.
IV.
V.
SUMMAR Y OF CONTENTS. . . . . . . . . . . . . . . . .
STEAM GENERATION. . . . . . . . . . . . . . . . . . .
CORROSION. . . . . . . . . . . . . . . . . . . . . . . . .
BOTTOM RESIDUES. . . . . . . . . . . . . . . . . . . . .
REFUSE CHARACTERISTICS. . . . . . . . . . . . . . . .
Vl
Page
C-17
C-26
C-27
C-27
C-27
C-27
C-30
C-30
C-30
C-36
C-37
C-37
C-37
C-37
C-38
C-38
C-38
C-40
C-42
C-44
C-46
C-46
C-49
C-54
D-l
D-2
D-IO
D-12
D-12
-------
I'
VI.
VII.
VIII.
IX.
TABLE OF CONTENTS- Continued
AIR POLLUTION ASPECTS. . . . . . . . . . . . . . . . . .
RELATED TH-ERMAL PROCESSES .- . . . . . . . . . . . . .
RELATED WASTE HANDLING PROCESSES. . . . . . . . .
AUTHOR INDEX. . . . . . . . . . . . . . . . . . . . . . . .
APPENDIX E - G LOSSAR Y
. . . . . .
............
. . . .
I -
I --
Vll
Page
D-16
D-20
D-22
D-25
E-l
-------
Table No.
A-I.
A-2.
A-3.
A-4.
B-I.
B-2.
B-3.
B-4.
B-5.
B-6.
B-7.
B-8.
B-9.
TABLES
APPENDIX A
Chemical Analyses of Refuse-Fired Furnace Deposits
Summary of Operating Conditions of Steam-Producing
Incinerator Plants. . . . . . . . . . . . . . . . . . .
. . . .
Typical Ash Analyses (wt-%) From Different Boilers
. . . .
Comparative Analyses (wt-%) of Bulk and Inside Layers of
Ash Samples. . . . . . . . . . . . . . . . . . . . . . . . . .
APPENDIX B
Summary Performance of Ten Selected Steam Generators. .
Capital Costs of Ten Selected Steam Generators. . . . . . .
Plant Total Energy Costs of Ten Selected Steam Generators
Kraftwerk- Union Computation Procedure for Deriving
Energy Production Costs. . . . . . . . . . . . . . . . . . .
Breakdown of Capital Costs for 200 and 400 MW Boilers
Personnel Requirements for a 300 MW Coal-Fired Power
Station. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Classification of Fuels
. . . . . . .
.............
Characteristics of Anthracite Fuels. .
. . . . . .
. . . . .
Characteristics of Lignite and Peat
. . . . . . .
. . . . . .
B-IO. . Summary of Particle Emission Data. . .
B-1l.
B-12.
B-13.
B-14.
..........
Summary of Gaseous Pollutants (ppm, dry basis) from Coal-
Fired Power Plants. . . . . . . . . . . . . . . . . . . . . .
German Plant Design Data
......
. . . . .
. . . . . . .
Electrostatic Precipitator
.......
. . . . .
. . . . . .
Summary of Efficiency- Test Data for Munich Units -
Material Balances. . . . . . . . . . . . . . . . . . . . . .
Vlll
Page
A-2
, A-3
A-2l
A-25
B-38
B-51
B-56
B-6l
B-64
B-65
B-66
B-67
B-70
B-90
B-95
B-l26
B-l27
B-130
-------
Table No.
B-15.
B-l6.
B-17.
B-l8.
B-l9.
B-20.
B-2l.
C-l.
C-2.
C-3.
C-4.
C-5.
C-6.
C-7.
C-8.
C-9.
C-lO.
.'. ".
TABLES - Continued
Summary of Efficiency-Test Data for Wsseldorf and
and Stuttg~rt Units - Material Balances. . . . . . .
Summary of Efficiency-Test Data for Munich Units
Heat Balances. . . . . . . . . . . . . . . . . . . .
'" '" '" '"
'" '" '" '" '"
Summary of Efficiency-Test Data for DUsseldorf and
Stuttgart Units - Heat Balances. . . . . . . . . . .
'" '" '" '"
Summary of Dust- Collector Performance Data for Munich
Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
"
Summary of Dust-Collector Performance Data for Dusseldorf
and Stuttgart Units. . . . . . . . . . . . . . . . . . .
Properties of Fly Ash from German Plants
European Field- Trip Itinerary. . .
'" '" '" '" '"
'" '" '" '"
'" '" '" '"
APPENDIX C
Estimated Equipment Life
'" '" '" '" '"
'" '" '" '" '" '" '" '" '" '" '" '"
Case 1 - Steam Generator Design and Cost Information
Cases 2 and 8 - Steam Generator Design and Cost informa-
tion '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '"
Case 3 - Steam Generator Design and Cost Information. . .
Case 4 - Steam Generator Design and Cost Information
Case 5 - Steam Generator Design and Cost Information
Cases 6 and 7 - Steam Generator Design and Cost informa-
tion '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '" '"
Case 9 - Steam Generator Design and Cost Information
Case 10 - Steam Generator Design and Cost Information,
Items Included in Steam Generator Costs. . . . . . . . . . .
'lX
Page
B-131
B-132
B-133
B-140
B-141
B-l43
B-146
C-2
C-6
C-7
C-8
C-9
C-IO
C-ll
C-12
C-13
C-14
-------
Table No.
C -11.
C -12.
C -13.
C -14.
TAB LES - Continued
Installed Cost of Limestone Scrubber Injection Equipment,
Excluding Wet Scrubber and Reheat System. . . . . . . . .
Cost Estimate Summary of Receiving and Storage Facilities
and Equipment. . . . . . . . . . . . . . . . . . . . .
Labor Requirement and Cost. .
. . . .
.....
......
Cost Equations for Conventional Fossil Fuel Power Plant
x
Page
C-31
C-33
C-39
C-48
-------
Figure No.
A-I.
A-2.
;~- .
A-3.
A-4.
A-5.
B-l.
B-2.
B-3.
B-4.
B-5.
B-6.
B-7.
B-8.
B-9.
B-IO.
B-ll.
B -12.
B-13.
B -14.
B -15.
FIGURES
APPENDIX A
, Typical Location of Corrosion in Large Steam-Generating
Incinerators. . . . . . . . . . . . . . . . . . . . . . . . . .
Chloride Corrosion from Firing Refuse
. . . .
. . . .
Alkali Sulfate Corrosion from Firing Refuse
.....
Reactions of Iron and Sulfur Compounds. . . '. . .
.....
Softening Temperature Versus Ash Base Content
......
APPENDIX B
Historical Trends in Steam Conditions. . . . . . . .
. . . .
Section of Welded Panel- Wall. . . . .
.........
Typical Emplacement of Welded Panel-Wall .
........
Basic Circuits for Achieving Recirculation at Full Load
Effect of Pressure on Density of Steam and Water. .
. . . .
'Principle of Once-Through Steam Generator.
. . . .
. . . .
Typical Boiler Fluid Temperatures
. . . .
. . . .
.....
Once-Through Boiler Systems
......
......
. . . .
Sulzer Once-Through Steam Generator. . . . . .
......
Benson Circuitry for Subcritical Service.
. . . . . . . . . .
Benson Circuitry for Super critical Service
......
Structural Similarities of Modern Boilers Operating by
Different Processes. . . . . . . . . . . . . . . . . . .
Various Types of Once-Through Evaporator s
. . . . . . . .
Meander-Strip Evaporator for Front Wall Firing. . .
Typical Configuration of Small (50-100 MW) Power Boiler
xi
Page
A-5
A-ll
A-13
A-14
A-23
B-5
B-8
B-9
B-12
B-13
B-14
B-15
B-16
B-18
B-19
B-20
B-21
B-23
B-24
B-25
-------
Figure No.
B -16.
B-1?
B-18.
B-19.
B-20.
B -21.
B-22.
B-23.
B-24.
B-25.
B -26.
B-2?
B -28.
B -29.
B-30.
B - 31.
B - 32.
B-33.
B-34.
B - 35.
B-36.
FIGURES - Continued
Typical Configuration of Intermediate to Large (100-400 MW)
Power Boiler. . . . . . . . . . . . . . . . . . . . . . . . .
Typical Characteristics of Combination Radiant and Convec-
tion Superheater s . . . . . . . . . . . . . . . . . . . . . . .
Conservative Arrangement of Heat Absorbing Surfaces
Furnace Heat Absorption in Steam Generators
. . . . . . .
Typical Absorption Variation in Radiant Tubes
.......
Pulverizer Firing System. .
......
. . . .
o . . .
Multi-Fuel Burner. . . . . . .
. . . .
.....
..0...
Cyclone Fired Furnace.
. . . .
......
......
Selected Steam Generator Designs - Unit No.1
.......
Selected Steam Generator Designs - Unit No.2.
. . . . . .
Selected Steam Generator Designs - Unit No.3. .
.....
Selected Steam Generator Designs - Unit No.4. . . . . . .
Selected Steam Generator Designs - Unit No.5.
......
Selected Steam Generator Designs - Unit No.6.
. . . . . .
Selected Steam Generator Designs - Unit No. ? . . .
. . . .
Selected Steam Generator Designs - Unit No.8. . . . . . .
Selected Steam Generator Designs - Unit No.9.
......
Selected Steam Generator Designs - Unit No. 10
. . . . . .
Boiler Plant Equipment Cost.
......
.....
.....
Turbine Generator Equipment
. . . . . .
.......
Specific Power Plant Capital Costs
.............
xii
Page
B-2?
B-28
B-29
B-30
B-32
B-33
B-34
B-36
B-39
B-40
B-41
B-43
B-44
B-45
B-46
B-4?
B-48
B-50
B-52
B-53
B-5?
-------
Figure No.
B-37.
B-38.
B-39.
B -40.
B - 41.
B -42.
B-43.
B-44.
B-45.
B-46.
B-47.
B -48.
B-49.
B-50.
B-51.
B-52.
B-53.
B-54.
., .
."'. '"" .
FIGURES - Continued
Specific Power Plant Total Energy Production Costs, -
Lignite. . . . . . . . . . . . . . . . . . . . . . . .
. . . .
Specific Power Plant Total Energy Production Costs - Coal
Specific Power Plant Total Energy Production Costs - Gas
or Oil. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anthracite-Fired Steam Generator
......0
Black-Liquor Recovery Unit. . . .
.....
. . . .
. . . .
Wood- Waste Fired Steam Generator With Spreader Stoker
Wood-Waste Fired Steam Generator With Inclined Water-
Cooled Grate. .' . . . II . . . . . . . . . . . . . . .
. . . .
Fusion Temperatures of Bark/Coal Ash Mixtures
. . . . .
Refuse-Fired Steam Generator
.....
. .. . . . .
. . . .
Gas Flow ~ Generator Output.
. . . .
. . . .
.......
Dust Concentration: Suspension-Fired Furnace
......
Dust Concentration: Cyclone Furnace
........
Size Distribution of Flue Gas Particles - Pulverized Coal
Fir ed in Su s pens ion. . . . . . . . . . . . . . . . . . . . .
Size Distribution of Flue Gas Particles - Crushed Coal
Fired in Cyclone Furnace. . . . . . . . . . . . . . . . . .
Size Distribution of Flue Gas Particles - Coal Fired on
Grates. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Relationship of Fly Ash Resistivity to Coal Sulfur-Content .'
Effect of Fly Ash Moisture Content on Resistivity ~ . . . .
Estimation of Average Unit NOx Emissions from Similar
Pieces of Combustion Equipment. . . . . . . . . . . . . .
xiii
Page
B-58
B-59
B-60
B-68
B-72
B-73
B-75'
B-77
B-79
B-83
B-84
B-85
B-87
B-88
B-89
B-92
B-93
B-97
-------
Figure No.
B-55.
B-56.
B-57.
B-58.
B - 59.
B-60.
B -61.
B-62.
B-63.
B-64.
B-65.
B~66.
B-67.
B-68.
B-69.
B-70.
B - 71.
B -7 2.
. B -7 3.
FIGURES - Continued
Estimation of Average Unit NOx Emissions from Larger
Sized Combustion Systems. . . . . . . . . . . . . . . . . .
Multi-Cyclone Tube Element
.......
0.....
Cyclone Dust Collector - Expected Micron Efficiency. . .
Variable-Orifice Liquid Scrubber
. . . .
..0..
.....
Multi-Element Bag House. . . .
o . G .
0...0..
Precipitation Rate ~ Fly Ash Resistivity - Field Data. . .
Single-Stage Electrostatic Precipitator. .
OGO...OCltO
Electrostatic Precipitator Installed Costs ~ Gas Throughput
Flow Diagram - Reinluft Process. . . . . . .
. . . .
Flow Diagram - Catalytic Oxidation Process. .
Flow Diagram - Alkalized Alumina Process
.....
Flow Diagram - Dolomite/ Limestone Injection.
......
Munich North Combined-Fired Steam Generator - Block I .
Munich North Combined-Fired Steam Generator - Block IT
" .
Dusseldorf Refuse-Fired Steam Generator. . . . . .
Stuttgart Combined-Fired Ste.am Generator - Unit 28
Stuttgart Combined-Fired Steam Generator - Unit 29
Precipitator Performance vs Gas Temperature - Munich
Plant s ............................
Precipitator Performance vs Gas Temperature - German
and U. S. Data. . . . . . . . . . . . . . . . . . . . . . . .
xiv
Page
B-98
B-IOO
B-l02
B-103
B-I05
B-I06
B-107
B-I09
B-lll
B-1l2
B-1l3
B-114
B-1l7
B-1l9
B -120
B-122
B-123
B-136
B-137
-------
Figure No.
C-l.
C-2.
C-3.
C-4.
C-5.
C-6.
C-7.
C-8.
C-9.
C-10.
C -11.
C -12.
C-13.
C -14.
C-15.
C -16.
C-17.
C -18.
FIGURES - Continued
APPENDIX C
Capital Cost of Land.
......
. . . . . . .
........
Capital Cost of Structures.
........
..........
Capital Cost of Water Treatment Equipment
.........
Capital Cost of Pumps.
......
. . . .
. . . . . . . . . .
Capital Cost of Piping. . . . . . .
. . . .
..........
Capital Cost of Coal Handling Equipment
........
Capital Cost of Residue Handling Equipment
.........
Capital Cost of Stacks. . . . . . . . . . . . .
........
Capital Cost of Turbine - Generator Equipment... .
.....
Purchase Cost of Electrostatic Precipitators
.....
Costs of Electrostatic Precipitators for Municipal Refuse
Incinerator s . . . . . . . . . . . . . . . . . . . . . . .
Purchase Cost of Wet Scrubbers
.....
.....
.....
Truck Delay and Station Costs
.............
Operation and Maintenance Cost of Shredders
........
Page
C-4
C-5
C-l9
C-20
C-2l
C-22
C-23
C-24
C-25
C-28
C-29
C-32
C-35
C-41
Operation and Maintenance Cost of Electrostatic Precipitators C-43
Operation and Maintenance Cost of Wet Scrubbers
Credit for the Sale of Power Versus Plant Size
. . . . . . .
Normal Population Distribution in a Typical Study Area
xv
C-45
C-47
C-52
-------
APPENDIX A
WASTAGE AND FOULING
-------
1.
LITERATURE SURVEY
A.
INTRODUCTION
An extensive survey was made of the literature to establish the
background necessary to evaluate the ash deposit-corrosion problem in
refuse-fired steam generators and to supplement the information generated
in the laboratory and the data gathered through field interviews. A total of
33 articles directly related to the subject matter were reviewed, with about
half of these articles being translated from the German. A large number of
articles indirectly related to the subject were also reviewed to provide back-
ground in specific areas such as corrosion due to complex alkali sulfates,
lead oxide, etc.
In reportin.g the results, the German workers have dealt pri-
marily with theories explaining the mechanism of corrosion through chemical
models. Unfortunately, they have minimized the importance of reporting the
circumstances under which the deposits formed or corrosion took place, and
therefore the chemical models remain largely unconfirmed. Only recently
has work of any merit been reported on laboratory investigations made to
support existing theories or explain field results (Ref. A-I). The lack of
data may be illustrated by the tabulation of chemical analysis of deposits
appearing in Table A-I, the data representing the entire sum of analyses
reported in the thirty-three papers.
. The conditions under which the corrosion and deposits occur are
first reviewed and this is followed by a review of the mechanisms proposed
in addition to a summary of the results.
B.
OPERA TING CONDITIONS
The literature reviews in varying extent the corrosion problems
in approximately 11 different installations representing a variety of operating
conditions and boiler designs. The operating data relevant to the corrosion
or ash deposit problem have been tabulated for each plant in Table A-2 and it
is apparent that there is no single contributing factor to corrosion. A number
of factors, such as type of refuse, operating temperature, or individual details
in design, all influence metal wastage. In some cases there appear to be con-
flicting data.
Corrosion in general is reported to occur on the upstream (leading)
edges of superheater tubes in the first few rows of the tube bundle beneath de-
posits that are not porcelainized, and where the tube metal temperatures ex-
ceed 850oF. In 'some cases, the lowest temperature limit one might expect
A-I
-------
TABLE A-I - CHEMICAL ANALYSES OF REFUSE-FIRED FURNACE DEPOSITS
v..r I'.-Z ltd. 1\- 4(1 ) H.~L ,\-~(~)
Upstream Downst::-cam Scale-Like Layer Under Corr. Layer Inside Surfac e Middle I'\~lJ.r Flue Gas
C0:J.stituent W.S.FP) ~I. F.(4) Ref. A-3 ~ Below ~ Below W.S.F. W.I.F. W.S.F. W.I. F. W.S.F. \V.I.F. W.S.F. W. I. F. W.S.F. il'. I. F. R~,
:-1"20 3.84 3.6 3. J 2 4.87 5.00 11.75 1.0 3.9 3.9 3.4 3.9 3. b
14-24
1':2° 6.20 11.5 3.31 5.12 2.56 6.75 3.6 0.7 19.2 16.9 12.7 7.9
C..O 5.40 16.4 1.85 2.45 1.50 0.7 7.2 9.8 2.0 4.5 5.7 10-2C
Fe203 1.45 4.00 15.4 56.7 24.8 63.8 17.6 Tr. 75.5 Tr. 18.0 0.8 9.2 1.2 5.2 1.2 4.4 1-13
AIZ03 1.53 ' 9.40 7.4 8.9 11.5 8.6 2.2 2.1 3-16
~:gO I. 50 4.0 0.2 1.5 9.8 7.7 5.3 0.5-4. C
PZ05 0.3 1. 1 0.6 0.9 1.4
ZnO 4.75
503 15.60 4.84 29.4 0.14 0.25 0.18 0.25 4.1 31.6 32. 1 16.2 6.0 25.8 4.8 23.4 3.7 30-48
C02 11.60
Cl 6.4 5.5 6.1 4.8 4.3 Tr. 6.0 0.1-0.4
TiOZ 0.90
Si02 11.90 11.5 2.51 3.21 0.81 2.57 0.9 4-14
>
I PbO 14.00 0.6 5.1 5.5 21. 1 5.0 19.8 4.0 21.5
tV
50~ 12.85 28.38 11.75 37.80
5 4.30 9.50 4.05 12.75
pH 5.3 3.9 4.7 4.1 4.0
"0 Wa.tf:r S
-------
TABLE A-2
SUMMAR Y OF OPERATING CONDITIONS OF
STEAM-PRODUCING INCINERATOR PLANTS
Pres sure, Temp, % Excess
Plant psig of Stoker Air
Stuttgart 1135 975 Roller Grate
Munich 3000 985 Backward Feed Re- 80
ciprocating Grate
D{{sse1dorf 1314 932 Roller Grate 100
Rosenheim Sat. Steam 205 Roller Grate
Mannheim 1950 932 Traveling Grate
BASF 426 572 Von Roll Grate
Rotte rdam 516 800 Martin Grate 60
Es sen- Karnap 1470 932 Traveling Grate
Issy-les -Moulineaux 880 770 Reverse Reciprocating 100
Oceanside 460 462 Ro cking 128
Norfolk 300 420 Detroit Reciprocating 50
I -
A-3
-------
to find corrosion was set between 9300F and 9500F. The variation may be
due to a difference in composition of deposits. To a lesser extent it may be
due to the procedure used for estimating tube metal surface temperature.
In the Munich plant, there were a few isolated cases in which corrosion
was reported on the bare side or the downstream side of the tube surface.
Figure A-I illustrates the locations in which corrosion has been reported
in most cases.
Corrosion in the superheater banks is reported to occur at a
catastrophic rate at first and then gradually subside as the ash accumulation
increases. After 500 hours, metal loss of 0.0047 in. was measured, and
0.0078, 0.013, and 0.016 in. after 1000, 3000, and 5000 hours respectively
(Ref. A-7). In numerous cases the deposits accumulated in this zone are
reported to contain quantities of HZS and release a strong odor upon heating
or crushing.
One investigation (Ref. A-8) indicated the corrosion rate "be-
comes less when the percentage of ash content in the waste fuel increases II
(in winter, i. e. ).
Most investigations have attributed corrosion in these zones to
complex alkali iron sulfates, and hydrochloric acid resulting from the burning
of polyvinyl chloride. Typical of information available in this area, it is re-
ported that the plant with the highest HCI content in the flue gas reports no
corrosion damage at all, and the SOZ content of the flue gas in refuse in-
cinerators is reported to be below the level essential to support the for-
mation of the complex alkali iron sulfates.
Huch (Ref. A-5) indicates the deposits are not typical of those
usually associated with sulfate-type corrosion from either the complex
alkali iron sulfates or the pyrosulfates, even though he reports a positive
identification of the former in a deposit removed from a tube. I'Sulfide
formation could not be detected. For salt glaze corrosion, the tube walls
with their temperature at about 66zoF were at too Iowa temperature com-
pared with the fusion and sintering temperatures of the coating on them,
which were found to be Z19zoF and 7Z50F, respectively. Areas of partial
fusion that were observed were never found on the tube wall, but only in
such places where the heat flow to the cooling tube had been retarded by
cavities in the coating, or where the distance from the tube wall was already
fairly large so that the temperature compared to the tube wall was already
much higher. II
Nowak (Ref. A-9) reports more than one type of corrosion ap-
pearing in the superheated banks. The second type he attributes to vana-
dium in the oil fired with the refuse in the Stuttgart plant. Flame photo-
metric tests identified the presence of traces of vanadium in deposits.
A-4
-------
FIGURE A-1. TYPICAL LOCATION OF CORROSION IN LARGE STEAM-GENERATING INCINERATORS
A-5
-------
Corrosion appears to occur despite the types of fuel used; i. e. ,
refuse only, refuse and oil, or refuse and coal. In one plant, in which no
corrosion has been reported (Essen-Karnap), the relative location at which
the two fuels are burned has been considered a contributing factor to the re-
duction in corrosion. There are several other factors that must be considered
in this case which will become more apparently shortly; (1) the combustion
process is complete, assuring the elimination of a reducing atmosphere, and
(2) all metallic material is removed prior to burning the refuse.
A second type of "corrosion" has been reported in the convection
passes. It occurs at low gas temperatures and is prevalent around tube han-
gars and areas where gas passages take a change in direction. This is ac-
tually not corrosion, but erosion due to the high gas loading of large particulate
material. Nowak (Ref. A-7) reports that "during the winter months especially
high dust loadings of 8 to 109 /m3 were noticed, and in some cases the dust
loading of the flue gas reached 15 g /m3." These gas loadings approach the
limits expected of a high ash fossil fuel and if localized gas velocities are
allowed to exceed 100 ft/sec, erosion can be expected.
The most severe corrosion is reported to occur in furnaces when
the radiant superheater has a tube metal temperature of 9500F, or when water
wall tube metal temperatures are about 6000F. Nowak (Ref. A-7) summarizes
this problem as follows: "The appearance of the corrosion on the tubes in the
combustion chamber is similar to that on the finishing superheater tubes. Be-
neath shell-type deposits, brittle oxidation layers were found. As with the
finishing superheater tubes, these tubes were checked frequently with ultra-
sonic instruments for loss of wall thickness. Here, however, the material
loss continues approximately linearly*, while in the superheater the corrosion
process is steadily decreasing and approaches an asymptotic limit. The first
tube failures occurred after 5500 operating hours. It was noted that the tubes
of the wall superheater are affected equally, while the corrosion of the evapo-
rator surfaces is more pronounced in certain areas. These tubes are especially
endangered in the corner of the furnace, while there is essentially no corrosion
on the furnace rear wall tubes. It should be recalled that the superheater steam
temperature is 750 to 8250F while the tube temperature of the evaporator tube
is 5350F. No direct influence of wall temperature upon intensity of corrosion
is obvious, and it is believed that these results occur as a result of oxygen
deficiency in the flue gas composition in various areas of the furnace, the
effect of secondary air, and erosion. "
Corrosion of possibly two different types might be taking place,
one at 9500F plus and the other at a temperature of 600 to 7000F. The
literature is not entirely clear in this matter as some investigators report
a variety of corrosion phenomena between 6000F and 11000F (Ref. A-5, -10,
and -II). It would appear that temperature, physical location, and local
""Loss, in inches, at each 1000 hours (through 5000) equalled 0.0094, 0.020,
O. 033, 0.048, and 0.068.
A-6
-------
environmental conditions within the furnace all affect the extent and type of
corrosion. For example, the corrosion limit for an oxidizing environment
appears to be about 850oF. Corrosion can occur at lower temperatures,
however, if reducing conditions exist.
Little mention is made of corrosion at lower temperatures. One
area to expect such attack would be at the flue gas exit from the plant because
6f the low SOZ levels, high ash loading, emission from air heaters, and rela-
tively high exit gas temperatures from the economizer. Corrosion can be
expected during outage periods, although it has not received much attention.
Eberhardt (Ref. A-IZ) indicates deposits of 30-50 percent S03 with CaS04
are hygroscopic and attract water. After a short time an emulsion of
HzO-FeZ03 flows from the heating surfaces and typical dewpoint corrosion
occurs.
C.
INITIAL REMEDIES
Attempts have been made to minimize these problems with
reasonable countermeasures. They have been summarized by Nowak (Ref.
A-7).
Corrosion in the furnace was countered by studding the tube
surface and covering the area subject to corrosion with refractory. The
refractory was placed on those surfaces on which the flame front impinged
during operation. The method was used in the Munich incineration plant
and 18 months of operating experience was accumulated as of Mr. Nowak1s
reporting date of November 1968. No corrosion was found under the pro-
tective coating. Although a O. 4-in. thick layer of ceramic is not gas tight, .
it appears that the prevention of slag build-up eliminates the corrosion at-
tack. The lower cooling tubes were protected in the same manner. Most
likely these will require a removal of the refractory layer more frequently
than the furnace tubes because of the additional erosion.
The convection surface could not be treated the same way, and
a different approach had to be taken. The hottest tubes, which were most
susceptible to corrosion, were covered with various layers of chromium
steel and aluminum oxide by use of different methods. It was impossible
to obtain a completely smooth surface, and, as a consequence, corrosion
started at pores and continued beneath the protective layers, which then
broke off locally.
Shields made of Sicromal were applied to the leading edge of
some tubes and both sides of the tube in other cases. The shields were
not tightly fitted into the tube. Slag deposits were prevented from coming
in contact with the tube material and sufficient corrosion protection was
obtained.
A-7
-------
Nowak (Ref. A-7) reports that "with these shields, only gas
corrosion can be obtained on the tube surface, which does not endanger
the tube material. Disadvantageous is the reduced heat transfer rate to
the superheater tubes; however, this is not too critical because only the
uppermost superheater tubes will be affected. "
Another approach being taken is to arrange the superheater
in the gas pass of a conventionally fired unit.
For some time it was hoped to eliminate corrosion by the use
of additives. All these attempts were unsuccessful. The slag deposits
were of a different consistency and were easily removable, but a reduction
in corrosion could not be achieved. It also proved too costly to neutralize
the relatively large amounts of fly ash by additives.
With regard to a reduction in erosion, Nowak has indicated that
areas of highest gas velocities and dust loading should be modified by a suitable
design rearrangement based on gas dynamics. He felt the boiler manufacturers
would learn from experience how to layout the system to eliminate this danger.
In the field, the operator must use such practical means as shields, baffles,
etc.
D.
THEORY
The published background just discussed has been the base on
which much theory has been discussed in the literature. Most of the theory
is centered around chemical reaction based on reducing atmospheres, chlo-
rides, and sulfates. The importance of reducing environments was appro-
priately based on field experience. The chlorides were considered potentially
important based on the presence of polyvinyl chloride (PVC) in the refuse.
The sulfates were felt to be important based on U. S. experience and some
similarities that appeared to exist.
The theories proposed have been summarized recently in three
different papers by F~ssler, Leib, and Sp~hn (Ref. A-4); Defeche (Ref. A-13);
and Rasch (Ref. A-l4). .
1.
Corrosion by Reducing Atmospheres
Corrosion due to reducing atmosphere s has its origin in
the furnace during the combustion stage. It is attributed to improper mixing
of air and refuse, allowing some constituents to escape complete combustion.
The unspent material travels as part of a laminar flue gas into the cooler
zones of the furnace where it contacts various metal surfaces. Part of the
problem is attributed to the reverse gas flow in the furnace where some
material is destructively distilled off prior to reaching the high temperature
combustion zone.
A-8
-------
, . .:, ':" ~ '. ,'.
Rasch states the reduction of Fe203 to Fe304 takes place
easily in an atmosphere containing carbon monoxide:
3 FeZ03 + CO
~ Z Fe304 + COZ
The reduction of the Fe304 is more difficult, especially
in the low temperature range around 93zoF. The reaction is described as
follows:
Fe304 + CO
~ 3 FeO + COZ
The reduction of iron (II) oxide (FeO) to elemental iron
is possible only at high temperatures. At temperatures around 93ZoF the
course of the reaction is proposed to proceed by formation of a carbide
phase:
3 Fe ° + 5 CO
~ Fe3C +4 COZ
An investigation of corroded heat exchange surfaces indicates carbonization
doe~ occur.
Defeche indicates the reactions are very slow below 760oF,
but occur rapidly otherwise. The speed of the reactions, however, is en-
hanced by the alternating of oxidizing and reducing gas conditions.
2.
Corrosion by Chloride Compounds
Chloride corrosion has been attributed to burning of PVC.
F~ssler et al claim about 50% of the chlorine content of PVC results in the
formation of hydrogen chloride at temperatures above 4460F. The hydrogen
chloride can also be formed by alkali chloride hydrolysis (due to the high
water vapor content of the refuse flue gases) from about 7540F according
to the following reaction:
Z NaCl + H20
~ NaZ ° + Z H Cl
A third possible source of HCl would result from the re-
action between acid sulfates contained in the deposits and alkali chlorides
at temperatures from 39ZoF.
A limited amount of chlorine can also be expected, de-
pending upon the temperature and partial pres sure of OZ:
A-9
-------
.
Z HCI + 0z
catalyst
480-930oF '-
"" 18300F
Z CIZ + Z H20
F~s sler reports laboratory experiments indicating that
elemental chlorine is released according to the above reaction at tempera-
tures above 66ZoF when HCI-air mixtures are passed over tube deposits.
The formation of chlorine increases rapidly until IZ9zoF, at which time
it stops abruptly. At this point the ash becomes molten. The formation
was noted to be inhibited by water vapor.
Wickert (Ref. A-I) reported similar results when pas sing
HCI over iron shavings. The iron chloride that was formed was converted
with the oxygen present to FeZ03 and CIZ from about 7Z50F. Water inhibited
the formation of chlorine, and increasing amounts of S03 practically stopped
it altogether.
Laboratory tests by Stellar carried out at 8600F to I0400F
in flue gases from city gas burners with HCI added, showed that the test plates
without deposits are hardly attacked. On the other hand, corrosion could be
detected on plates with deposits.
Angenend (Ref. A-15) demonstrated in a test facility the
increase in corrosion activity of chlorine with temperature. These tests
were run in an invironment in which chlorine was added by injecting HC!.
Chlorine was also added by incorporating PVC with the refuse burned.
II
by Fassler:
The actual corrosion process has been explained as follows
"Hydrogen chloride or chlorine, in the presence of deposits,
can diffuse to the tube surface, where the free HCI or CIZ reacts with the sur-
face oxides and metal of the boiler tubes forming iron chlorides (57Z0F to 75Z0F).
Because the tube wall temperature is low compared to the flue gas temperature,
the progres s of the hydrolysis is very much retarded. The iron (Ill) chloride
(6000F boiling point) that is formed diffuses to regions of higher temperature
within the tube deposit and is decomposed to iron oxides and HCI and CIZ in
gaseous form (93Z0F to l11Z0F). II
The cyclic reactions des cribed can be represented as illus-
trated in Figure A-Z.
3.
Corrosion by Sulfur Compounds
As indicated by F~ssler et aI, the background on sulfate
corrosion is largely based on observations made in coal firing units. In
spite of his statement "It has not been possible to this day to find a clear
A-IO
-------
FeO, Fe203' Fe304
HEAT FeCi3
-..
HCI
CI2
Fe, FeO HEAT FeC12
Fe203 -
HCI H20
C12 j AIR
~
L
I
REFUSE
COMBUSTION
FIGURE A-2. CHLORIDE CORROSION FROM FIRING REFUSE
A-ll
-------
and final explanation of the corrosion mechanism, II it is nevertheles s pos-
sible to summarize the reactions that are being considered by most of the
investigators. The greater portion of investigators have tried to relate the
corrosion in the refuse units to the pyrosulfate and complex alkali iron sul-
fate attacks reported while firing coal.
The pyritic attack is usually associated with reducing con-
ditions resulting from flame impingement on water tube walls in the furnace,
with temperature ranging between 6000F and 800oF. The corrosion increases
with temperature, reaches a peak, and then subsides.
The complex alkali iron sulfate corrosion is usually asso-
ciated with metal temperatures of 9500F to 1100oF. It frequently occurs on
the leading edge of the first few rows of superheater tubes and is strongly
dependent on the existence of a liquid phase*. Once again, this corrosion
rate increases with an increase in temperature, reaches a peak and decreases
once again. The reaction is cyclic and has been described as follows:
Fe + K3 Fe(SO 4)3
t
1000-1300oF Fe203 + K2S04 + FeS
o I 02
S03. 2 S02 ''''The melting points of K2S04, K3Fe(S04)3, and K2S207 are approximately
19000, 11000, and 6000F, respectively, as the S content increases from
18 to 25%.
A-12
-------
>
I
0-
W
K2S04 Fe203 S03
t
> 925° F
,
K3Fe(S04'3
<9250F
I
Fe, Fe203 K2S207
TUBE SURFACE 570-9250F
- K2S04 S03
..
K20 S03
~
REFUSE COMBUSTION
'.
. ;-.
FIGURE A-3. ALKALI SULFATE CORROSION FROM FIRING REFUSE
-------
:x:-
I
......
*"
S02
Fe203 Fe203
Fe30 4 S03
Fe304
H2S
-
-
400- >9250F
925°F
AIR FeS S02 FeS04
~ AIR
H20 VAPOR ~
Fe2~ 803 Fe2(S04)3 H20 V APOA
.
FeS2
450"
9250F
750-
925° F
Fe Fe
Fe203 H2S,S S02,S03 Fe203
- -
Fe304 Fe30 4
REDUCING OXIDIZING
TUBE SURFACE TUBE SURFACE
REFUSE COMBUSTION
-.-
FIGUR : A-4. REACTIO I S ( : IRON AND SULFUR COMPOUNDS
-------
Defeche also suggests that the tubes act as a catalyst,
forming S03 in the presence of SOZ, with the formation of ferric sulfate as
an intermediate compound: .
Z FeZ03 + 6 SOZ + 3 0z
.. Z FeZ (SO 4)3
Fez (SO 4)3
~ FeZ03 + 3 S03
A part of this sulfuric anhydride reacts with the alkaline silicates and sodium
chloride of the deposits to form alkaline sulfate.
S03 + NaZSi03
~ NaZS04 + SiOZ
S03 + z NaCl + HZO
~ NaZS04 + Z HCl
The silicates are a product of the reaction of alkaline chlorides and of silica:
Z NaCl + SiOZ + HZO
.. NaZSi03 + Z HCl
The sulfuric anhydride reacts also with the alkaline sulfates
to yield pyrosulfates, which attack the ferric oxide protecting the tubes to yield
an alkaline sulfate of iron, which is broken up and results in a renewal process.
The reactions may be summarized as follows:
NaZS04 + S03
~.NaZSZ07
3 NaZSZ07 + FeZ03
. Z FeNa3 (SO 4)3
Z FeNa3 (SO 4),3
. FeZ03 + 3 NaZS04 + 3 S03
In addition to the attack by the alkaline sulfates, Defeche
suggests the direct attack of iron by the oxides of sulfur; e. g. :
3 S03 + Z Fe
. FeZ03 + 3 SOZ
He also points out the possibility of sulfite formation through
the reduction reactions of carbon and carbon monoxide:
Z NaZS04 + C
. Z NaZS03 + C02
NaZS04 + CO
~ NaZS03 + COZ
A-I5
-------
These sulfites are very unstable and decompose to yield the extremely corro-
Slve sodium sulfide according to the reaction:
4 NaZS03
. 3 NaZS04 + NaZS
The NaZS acts in turn on silicon oxide to form a sulfide of silicon that is
equally corrosive:
4 SiOZ + NaZS + 2 NaZS04
. 3 NaZSi03 + 3 S02 + SiO
SiO + NaZS
~ SiS + NaZO
SiO + SiOZ + NaZS
.. SiS + NaZSi03
SiO + CO
~ Si 0z + C
4.
Experiences with PbO
It has been indicated that zinc and lead appear in deposits
in relatively large quantities for minor constituents. Lead, in particular,
appears to be associated with the excessive oxidation at high temperatures.
Sawyer (Ref. A-ZO) has reported catastrophic damage of stainless steels at
elevated temperatures similar in nature to the corrosion by molybdenum
trioxide. Buckland, et aI, (Ref. A- Zl) has also reported corrosion due to
the presence of lead at elevated temperatures.
There are several possible ways in which corrosion may
be taking place. It is possibly due to the thermal decomposition of Pb304,
Newby and Dumont (Ref. A-Z2) stating that it decomposes at 93ZoF, which
is certainly in the temperature range of the corrosion problem. The equi-
librium reaction, describing the dissociation of Pb304' is as follows:
..... 6 PbO + Z °
Z Pb3 ° 4 ...
The dissociation pressure is 5 torr at 83zoF, 60 torr at 93zoF, 183 torr at
1 032°F, and 765 torr at 1170oF. It is conceivable that a cyclic process may
occur with frequent changes in flue gas temperature, with the periodic re-
lease of oxygen at the tube surface causing the high-temperature corrosion.
The basic lead chloride PbClZ. PbO (Matlockite) is another
compound included in Newby and Dumont's test that thermally decomposes
in the vicinity of 900 to 1000oF. In this case, chlorine, which could be a
dangerously corrosive agent, would be released.
A-16
-------
A third possibility would involve the reaction of lead
chlorides with water at the lower temperature. This reaction could result
in the liberation of lead oxide and hydrogen chloride:
..... Pb ° + Z H Cl
PbCIZ + HZO,
Either compound would be dangerous if the temperature were sufficiently
high to cause further thermal dissociation.
As in the case of the alkalies, the postulations regarding
lead are not without contradictory evidence. That these lead compounds
arrive at the tube without thermally breaking down may be due to the short
residence time in the flue gas. Possibly the compounds are formed during
the destructive distillation of the refuse and are transported to the tube by
the relatively large quantities of excess air present that escapes the com-
bustion process. No explanation can be given for the low-corrosion rate
experience with Pb02 at 9500F.
E.
LAB ORA TOR Y INVESTIGATIONS
There is very little indication of experimental efforts to dupli-
cate field experience in the laboratory and thereby gain a better under-
standing of the mechanisms taking place. A recent paper by Wickert on
"The Accelerators of Corrosion in Furnaces II (Ref. A-I) is virtually the
only evidence of such activity. This work, however, is a most significant
contribution to the state-of-the-art as it duplicates without contradiction
most of the conditions reported thus far in this field. The work deals with
the acceleration of corrosion by sulfur dioxide, sulfur trioxide, hydrogen
sulfide, hydrogen chloride, oxygen, and water vapor by various constituents
found in the ash deposited on boiler tubes; i. e., K2S04, PbS04, PbO, Na2S04,
MgO, CaO, and SiOZ' The tests were run on many 10-CrMo-910 specimens
for six hours in oxidizing, reducing, and neutral atmospheres.
Wickert reports that alkali salts accelerate S03 corrosion.
His experiments demonstrate th~t the t~st gas (air with 2 vol-% HZ)' O. 7%
503' and 0.3% S02) caused a welght gam of less than 0.0008 Ib/ft up .
through 16500F, whereas in the presence of NaZS04 a maximum gain of
0.026 Ib/ft2 was observed at lZOOoF (O. 0070 Ib/ft2 at 11000 and 14300F).
At the higher temperatures, S03 dissociates to form S02 and the activity
of the S03 molecule falls off. It was also established earlier in his paper
that the Naz504 does not accelerate the 02 corrosion, but only the 503
corrosion. He points out that no substance other than VZ05 has been
found to accelerate 0z corrosion. .
Wickert shows that the alkali salts also accelerate HC1 corrosion.
In these experiments, the test gas alone (air with 10 vol-% H20 and 0.5% HCl)
caused weight losses of 0.0035 and 0.018 Ib/ft2 at 930 and 11000F, respec-
tively, and with KZS04 present, losses of 0.0087 and 0.055 Ib/£t2 were
A-17
-------
r--
observed at these temperatures. Wickert's tests show corrosion in this
case may take place in the absence of a liquid phase. He reports that the
K2504 placed on the steel sample was completely loose after the test. In
that no 502/02 or 503 were present in the gas, no bisulfate melts could
be formed.
Further tests with NaCl and Na2504 in an oxidizing environ-
ment indicate the potassium sulfates were most corrosive, followed by
the alkali chlorides, and then sodium sulfates. Mixtures of equal parts
of sodium and potassium sulfates are more corrosive than either con-
stituent by itself. K2504 in the absence of HCl more strongly accelerates
502/02 corrosion than Na2504, and the same is true for HCl corrosion
accelerated by the two alkali sulfates in the absence of 502 or 503' The
corrosion that is not accelerated is light. The alkali salts accelerate the
503 or 502/02 corrosions, but not the 502 corrosion. In the absence of
02, 502 also corrodes the steel, but this reaction cannot be accelerated.
CaO and MgO occur in ash deposits along with the alkali salts.
Wickert indicates that in a gas containing O. 5 vol-% HCI, 0.6 vol-% S02,
and 10 vol-% water, CaO accelerates corrosion above 10320F (seven times
faster at 1100oF). Below this temperature it retards the reaction slightly.
MgO behaves in the same manner but the acceleration is not nearly as great
(0.012 Ib/ft2 for the test gas at 11000F vs 0.018 Ib/ft2 in the presence of
MgO). The alkali salt accelerators increase their action in air with H20,
S02, and HCl starting at 7500F if they are mixed with CaO. MgO-alkali
salt mixtures retard the action of the pure alkali salts, but they do increase
the straight gas corrosion.
If CaO and MgO are combined with FeZ03 as ferrites, the gas
corrosion is increased only above 103zoF. Mixtures of CaO-Fe203 or
MgO. Fe203 with K2504 in a weight ratio of 1:1 reduce the gas corrosion
that is accelerated by K2S04 alone. At 1l000F they accelerate the straight
gas corrosion.
In gases in which HCl is not present, it was found that CaO and
MgO are not accelerants of S02/02 or S03 reactions up to 1000oF. They do
not retard the gas corrosion and the corrosion normally accelerated by
K2S04' They also reduce the activity of the accelerator. The ferrites of
calcium and magnesium behave similarly to CaO and MgO.
In an HCl environment containing no SOx, CaO is a strong re-
action accelerator. MgO increases the reactions only slightly.
Wickert investigated other substances also. He found that
Fe203 does not accelerate the reaction of air, 10% water, 0.6% S02, and
O. 5% HCl. Ferrous sulfate, ferric sulfate, and zinc sulfate do not accele-
rate the gas corrosion either. They only cause a slight increase in the gas
corrosion at higher temperatures because of splitting off of S02, S03, and
02' The chemically pure sulfates of the alkaline earth metals are very weak
A-18
-------
corrosion accelerators; CaS04 and BaS04 accelerate the reactions above
11 OOoF, while MgS04 has no noticeable influence. The CaS04 product
fornled in the gas streanl fronl CaO accelerates very strongly above
llOOoF and the sulfate from MgO noticeably. Wickert assumes that the
residual oxide content is responsible for the difference. .
According to Wickert, PbS04 accelerates the corrosion re-
actions considerably above 9500F for gases containing HCl as well as S02
or S03. He also found that PbS04 is inactive in a dry gas and accelerates
corrosion in the presence of water vapor.
It was found that PbO increased the corrosion rate in the pres-
ence of PbS04 in a manner similar to that of CaO and CaS04. When PbO
was used as a reaction accelerator, weight loss was six times more rapid
at l1000F than with PbS04 and deep corrosion pitting occurres in the short
period of six hours.
With a wet gas containing HCl and S02, it was found that mix-
tures of PbS04 + CaO (Z:1) and PbS04 + MgO (Z:l) greatly increased the
gas corrosion. A loss of 0.049 lb/ftZ was noted at 10800F for both mix-
tures, compared to 0.012 for the gas alone and O. OZ1 lb/ftZ for the gas
plus PbS04' A PbS04' SiOZ mixture retarded the corrosion to the level
of the straight gas.
It is pos sible that the balance of S02 and S03 in flue gas is
such that chlorine could form from HCI present. Tests run with C1Z in
the gas indicated that K2S04 is a strong accelerator for its corrosion
mechanism.
Tests were also run in neutral and reducing environments.
It was found that SOZ corrosion was not accelerated by alkali metal salts
in the absence of OZ. Acceleration of HCl corrosion did not require OZ.
In tests run with KZS04 and HC1, the solid coating on the metal sample
after the tests at all temperatures contained relatively large amounts of
combined chlorine. The water extraction had an acid reaction. If the
reaction gases contained SOZ/02 in addition to HCl, after the test there
was only a smiitll amount of combined chlorine in the coating. On the
other hand, if CaO was present instead of K2S04, then the coating after
the test again contains more combined chlorine.
KZS04 was found to be a strong accelerator (l4x at l1000F)
for HCl corrosion in wet neutral gas. At 7500F the coating was fused,
and at 9500F it was sintered; it contained chlorine at all temperatures.
In a reducing environment, the corrosion due to K2S04 with
and without S02 and HCl and mixtures of these two gases was heavy and
began at lower temperatures, as low as 6000F for some tests. The cor-
rosion product in tests involving a reducing atmosphere contained FeS,
A-19
-------
and the combustion gas contained organic sulfur compounds, sulfur, and
hydrogen sulfide. When KZS04 was used as an accelerant, the corrosion
products contained organic sulfur compounds, sulfur, and hydrogen sulfide.
In summary, Wickert indicates that, with few exceptions, the
ingredients found in refuse deposits accelerate gas side corrosion above
950oF. In the presence of a reducing condition the threshold temperature
could be reduced to as low as 600oF. The deposits we.re fused and re-
vealed the presence of HZS. In an oxidizing atmosphere containing HCI,
it was found that corrosion could take place in a "dry" unfused, powdery
ash.
II.
EXPERIMENT AL
A.
DIS CUSSION
On the present program, analyses were run at the Foster Wheeler
Corp. laboratories on composite samples removed from approximately 30
different locations in each of the boilers under study in Europe. Fewer
sampling locations were used in the boilers examined in the United States.
The sampling points include numerous locations on all four walls of the
furnace representing several elevations, upstream and downstream sides
of tubes located in the superheater bundle, and numerous locations in the
economizer. These sampling points provided a good representative samp-
ling of the ash deposited during flight through the boiler at various tem-
perature levels and gas-tube temperature gradients. In some cases the
corrosion produced was removed intact with the ash samples. In other
cases the corrosion product remained tenaciously attached to the tube.
Fortunately, on several occasions, the layer adjacent to the tube surface
could be removed from the tube as a sample separate from the bulk deposit.
The latter group of samples was analyzed as a separate group.
In the beginning, the first few samples were analyzed for a
large number of elements on the assumption that most elements could be
found in refuse to some degree. The analytical procedure was soon re-
duced to include only those elements appearing most frequently and the
elements which were of the most concern.
Tabulation of the results summarized in Table A-3 re'reals
numerous interesting facts. As suspected at the start, the ash deposited
very much resembled lignite ash and contained relatively large quantities
of calcium in proportion to the iron present. This similarity was con-
firmed by relatively low ash softening temperatures. If the chemical
composition in terms of the basic~:~ constituents present are compared with
~:< Calculation of the level of basic or alkaline constituents follows the
convention of omitting from the other constituents the Zn, Pb, and S
present.
A-20
-------
TABLE A-3
TYPICAL ASH ANALYSES (W T-o/c) FROM DIFFERENT BOILERS
Europe United States
Constituent Boiler 1 Boiler Z Boiler 3 Refuse Lignite
AIZ ° 3 16 17 8 11 11
SiOZ 11 13 15 Z6 18
FeZ03 Z 5 4 4 lZ
CaO 16 8 10 9 Z4
MgO Z Z Z Z 8
NaZO 3 Z 4 6 7
KZO 9 9 9 10 1
PbO 3 6 5 Z
2nO 4 8 6 8
S03 33 30 31 ZO 15
A-Zl
-------
the ash softening temperatures in Figure A- 5, it can be seen that this
same relationship holds for refuse and lignite. The lignite data shown
in Figure A-5 are Duzy's (Ref. A-23); the refuse ash data were generated
by Foster Wheeler Corp.
This analogy is also somewhat substantiated by the relatively
large quantities of sodium and potas sium appearing in the deposit. Sodium
varies between 0 and 5%, while potassium runs a little higher; both con-
stituents appear in the deposits consistently throughout the boiler. Their
presence becomes more pronounced in deposits from boiler zones having
lower gas temperatures.
The findings on chlorine were rather surprising. For the most
part, it was conspicuously missing from the European deposits. It did ap-
pear in small percentages (about 1% or less) in the ash removed from both
of the domestic boilers sampled. In the two cases in which it exceeded these
percentages, the sodium present was also proportionately high. No corro-
sion was associated with either of these two cases. It is possible that
chlorides did appear in larger concentrations in a very thin layer lining
the inside surface of the ash sample.
Zinc and lead were found in relatively large quantities. Neither
of these two elements was anticipated. Zinc, like sodium and potassium,
appeared rather consistently in most ash sampled. It ran between 9 and 10%
and increased in concentration with a decrease in gas temperature.. Lead
appeared somewhat sporadically, ranging from 0 to 13%. Presumably these
two elements are found in refuse as pigments, solders, galvanized coatings,
etc.
The minor constituents, which are usually defined as sodium,
potassium, zinc, and lead, comprise about 18-25% of the ash sampled at
gas temperatures below 17000F. The concentrations decrease with an
increase in temperature above this point, being approximately 15% at 18000
and 10% at 20000F. It was further noted that a rather constant relationship
appears to exist between the percent zinc and the combined percentage of
sodium and potassium. This relationship is best fit by the equation % Zn
= 1. 12 (% Na + K) - 1. 71. If lead is included with the zinc, it is found that
a linear relationship still exists, but in slightly different proportions. This
could be interpreted to mean that zinc, sodium, potassium, and lead are
depositing as some discrete compound or that liquid solutions are solidifying
at a particular composition. An examination of the ternary system of
Na2S04, K2S04, and ZnS04 indicated the percent zinc, sodium, and
potassium were reported in proportions that coincided with low melting
temperature phases (720-7400F) in this system (30-50% K2S04, 40-60%
ZnS04, and 10- 30% Na2S04).
A-22
-------
3000
REFUSE 0 0 fj.
2800, LIGNITE I} 0
II..
0
W
a::
:J
I- 2600
«
a::
w ~ 0
c:I.
:E
.w o.
I-
~ " 0 c;i yll
I z
N ~ 2400 -0 O~O~ II 60
V>
I-
II.. \ 6 % 06 ~
@
0 A
~ 0 ~ 0
. ~....o 660 CO 0
2200 .gg b . ro'~ 6
~ ~~ 00
2000 '*6 6
20 30 40 50 60 70 80
BASIC CONSTITUENTS, WT-%
FIGURE A-5. SOFTENING TEMPERATURE VERSUS ASH BASE CONTENT
-------
Chemical analyses were run on ash samples that comprised
only the inner layer of ash, either lining the corrosion product or the tube
surface. These analyses (Table A-4) indicate the presence of large quan-
tities of lead and potassium. In most cases, the percent lead in the inner
layer was? to 5 times greater than reported in the bulk sample. Consi-
derably less difference was observed in the potassium distribution. Zinc
and sodium were present in substantially lower quantities, and their level
of concentration apparently was not dependent upon location in the ash de-
posit. Ash fusion tests with conventional tetrahedron cones indicated that
portions of the ash can be expected to be liquid at temperatures as low as
1200-1700oF. The inside layer of one sample (removed from a domestic
boiler) that contained large quantities of lead, had an initial deformation
temperature as low as 850oF. Unfortunately, no relationship could be
established between the presence of a liquid state and chemical composition,
a much more sophisticated procedure apparently being required. It is
possible that small portions of a liquid phase could form at low temperatures
and remain undetected due to the wetting of the larger quantity of dry
material.
In general, the chemical analyses indicate that the ash com-
positions in all the boilers analyzed were very much alike. It would be
reasonable to assume that the results could be compared or extrapolated
from one boiler to another if the operating conditions were similar and
the refuse was within the compositional range normally found.
Practically all samples were examined microscopically as well
as chemically in order to detect clues that might shed light on the nature of
deposit corrosion. There was strong evidence that most of the chemical re-
actions responsible for the deposit problem took place at the tube surface.
Sintered ash found in the convection passes, as well as the furnace, con-
sisted of small spherical particles of fly ash IO microns in diameter or
less. Particles forming perfect spheroids indicate that they must have
been molten and solidified at one point in their flight through the boiler,
during which time the aerodynamic and gravitational forces were in balance.
At this point the particles behaved as a part of the gas stream. They must
have reached the tube surface by diffusion in a dry state after they had soli-
dified. This is confirmed by the fact that much larger particles, which are
subject to greater inertia forces, manage to pass through the maze of tubes
in the convection passes before collecting in the cooler zones.
Close examination of the deposits on a layer by layer basis
revealed that the particles comprising the inner layer show much greater
evidence of reaction with other constituents. The spheroids were distorted
and had a frosted appearance. Particles of fly ash situated on the outer
surface were predominantly perfect spheroids of clear "unreacted" material.
Much larger spheres of this description were also found at the cold end of
the convection pass.
A-24
-------
TABLE A-4
COMPARATIVE ANALYSES (WT-o/d OF
BULK AND INSIDE LAYERS OF ASH SAMPLES
Sample 1 Sample Z Sample 3
Constituent Bulk Inside Bulk Inside Bulk Inside
AlZ03 10 5 19 4 11 4
SiOZ ZI lZ 30 9 ZO 6
FeZ03 lZ 5 7 3 4 18
CaO 10 6 11 7 9 Z
MgO 3 1 3 Z
NazO Z 3 3 6 5
KZO 6 8 7 11 10 13
PbO 3 16 1 17 Z 6
2nO 6 6 6 6 8 9
S03 14 36 Z4 40 20 Z6
A-Z5
-------
Fused ash was found in the high temperature gas zones, but not
necessarily in those having the highest gas temperatures. Frequently, the
fused ash was preceded by accumulations of light sintered ash, indicating
unusual conditions existed when the deposits were forming. Gas tempera-
tures in these zones were estimated to be as much as 3900F below the initial
ash deformation temperature measured in the laboratory. In numerous cases
the inner layers of the deposits found in the cooler zones were fused, while
the other layers were sintered or almost powdery. Deposits forming on the
upstream side of the tube were fused solid, while ash of the same composi-
tion accumulated on the downstream side of the tube was powdery. Past
experience with ash deposits and recent work by Bishop (Ref. A- 24), indicate
that vaporized compounds of minor ash constituents, such as sodium, vana-
dium, etc., can condense as solids on surfaces whose temperatures are well
below the triple point even under conditions of high gas velocity.
Examination of the deposits revealed several other facts con-
cerning the ash deposit/corrosion problem. In many cases fused deposits,
when broken open, released a strong smell of sulfides. It is apparent that
despite the large quantities of excess air used in the boilers from which the
samples were taken localized reducing conditions existed. In one of the
boilers examined in the United States, the corrosion and ash deposition on
the tubes was heaviest in the portion of the tube bank either subjected to
flame impingement or in the immediate vicinity of the combustion zone.
Corrosion observed while removing the ash samples varied
throughout the boiler. With few exceptions, corrosion was associated
with the formation of the ash deposited. In some cases, the corrosion
product was removed with the deposit as a loosely attached scale. In
other cases, the corrosion product adhered tenaciously to the tube and
had to be separated from the ash. In one or two cases in the high gas
temperature zone of the boiler, there was evidence of a crystallized
material lining the tube side of the corrosion product. Although this
phenomenon was confined to a given section of the boiler, it was noted
in several different units. No attempt was made to identify the crys-
tallized material.
Corrosion reported in the furnaces of most European boilers
largely involved a zone on the furnace walls which would be outlined by the
projection of the flame shape onto the tube surface. This same area was
reported to be subjected to localized reducing conditions. The corrosion
product could usually be removed from the tubes as an intact scale having
a thin layer of sintered ash.
B.
CORROSION TESTS
Corrosion tests were run on all samples removed from metallic
surfaces by simply soaking small metallic specimens weighing about 15 to
20 grams in approximately 4 grams of ash for about 140 hours at 7500F and
A-26
-------
9500F in an oxidizing atmosphere. Each specimen measured approximately
1 in. x l/2 in. x 1 /4 in. and offered about 0.45 in.2 of surface area. When
soaked in the ash, about l/4 of the specimen was submerged in the ash and
3/4 was exposed to a normal atmosphere. All the specimens had a ground
surface finish.
All samples were cleaned with a solvent before the tests. After
the tests, they were descaled in a hot sodium hydroxide dip and 8% HCI '
solution inhibited with rudine. This was followed by a water rinse and
acetone dip.
The purpose of these tests was not to determine the oxidation
rates but to qualitatively indicate the type of attack and its order of mag-
nitude. Such a procedure was successfully used in studying the effects of
additives on the catastrophic oxidation of boiler tubes caused by vanadium
pentoxide. This type of test often reveals slight changes in the physical
characteristics of ash not normally indicated by standard technique.
v
The results of the tests are difficult to analyze, as there were
no obvious trends noted in the large quantity of data obtained. However,
there is some agreement between field observation and the laboratory re-
sults. Most of the corrosion took place at the 9500F level, although less
severe corrosion was experienced at 7500F on several occasions. Two types
of corrosion were noted. In one case, a brittle scale was formed around
the coupon that could easily be removed with the fingers. No liquid phase
was present in the ash, and the attack above and below the ash line was the
same. The evidence suggests corrosion promoted by the gaseous phase.
In the second case, a tight adhering scale was formed in the presence of a
liquid phase in the ash. The surface of the coupon below the ash line was
obviously pitted. Unfortunately, no relationship could be established on
the basis of chemical composition. Those few samples containing large
portions of chlorides did not necessarily show signs of excessive corrosion.
In many cases, the corroded speciments were those that were soaked in ash
that had been removed from boiler zones where corrosion had taken place,
while little corrosion was noted on coupons immersed in deposits obtained
from boiler zones where only slight corrosion occurred. However, this
situation did not hold for all cases, undoubtedly because of the lack of
duplication of boiler environment.
A-27
-------
Ill.
APPENDIX A REFERENCES
A-I.
A-2.
A-3.
A-4.
A-5.
A-6.
A-7.
A-8.
A-9.
A-I0.
A- 11.
A-12.
A-13.
Wickert, K., "The Accelerators of Corrosion in Furnaces, "
Wlirme, 74 (:1), 103-109 (1970).
Bowen,!. G., and Woodward, G. P. B., "Incineration of
Waste Materials, " The Comb. Eng. Assoc., Document 8411,
Index Fuel (e) 4, Trident House, Station Road, Middlesex,
England, Aug.. 30, 1968 (presented at the Assoc. Meeting,
Manchester, Feb. 27, 1967).
Eberhardt, H., and Mayer, W., "Experiences with Refuse
Incineration in Europe. Prevention of Air and Water Pollution,
Operation of Refuse Incineration Plants Combined with Steam
Boilers, Design and Planning, " Proceedings of the 1968
National Incinerator Conference, ASME, 73-86.
Flissler, K., Leib, M., and Sp~hn, H., "Corrosion in Refuse
Burning Boilers, " Mitteilungen der VGB, 48 (2), 126-38, April
1968 .
Huch, R., "Hydrochloric Acid Corrosion in Refuse Burning
Installations, " Brennstoff- W~rme-Kraft, ~ (2), 76-79 (1966).
Kohle, H., "Fireside Deposits and Corrosion in Refuse Boilers, "
Mitteilungen der VGB, 102, June 1966.
Nowak, F., "Corrosion Problems in Incinerators, " Combustion,
32 -40, November 1968.
Stellar, P., "Corrosion Measurements in the Steam Generator
of a Refuse Burning Installation, " Energie, .!2 (9), 278-80
(1967).
Nowak, F., "Operating Experience at the Refuse Burning Plant
at Stuttgart, II Brennstoff-W~rme-Kraft, .!2 (2), 71-6 (1967).
Stellar, P., "Experiments for Clarifying the Causes of Corro-
sion in Incinerating Plants, " Energie, ~, 355 -5 7, Aug. 1966
Nowak, F., "Corrosion Phenomena in Refuse Boilers, " Mittei-
lungen der VGB, 102 (6), 209-10, June 1966.
Eberhardt, H., "European Practice in Refuse and Sewage Sludge
Disposal by Incineration, " Combustion, 8-15, Sept. 1966.
"Corrosion Caused by the Incineration of Urban Residue, "
Work Group No.3, Fourth Int. Congress of G.!. R. O. M.
A-28
-------
A-14.
A-15.
A-16.
A-17.
A-18.
A-19.
A-ZO.
A-21.
A-22.
A-23.
A- 24.
Rasch, R., "Refuse and Waste Burning - Today's Technical
State and Future Development in View of the Changes in Refuse
Composition, " Chemiker-Ztg. /Chem. Apparatus/Verfahrens-
technik, 21., (10), 369 -78 (1969). \
Angenend, J., tiThe Behavior of Boiler Tube Materials in
Bases Containing HC1, " Brennstoff- W~rme-Kraft, ~ (2),
79-81 (1966).
Reid, W. T., Corey, R. C., and Cross, B. J., "External
Corrosion of Furnace Wall Tubes.!. History and Occurrence, "
Trans. ASME, May 1945.
Corey, R. C., Cross, B. F., and Reid, W. T., "External
Corrosion of Furnace Wall Tubes. II. Significance of Sul-
fate Deposits and Sulfur Trioxide in Corrosion Mechanism, "
Trans. ASME, May 1945.
Corey, R. C., Grabowski, M. A., and Cross, B. J., "Ex-
ternal Corrosion of Furnace Wall Tubes. III. Further Data
on Sulfate Deposits and the Significance of Iron Sulfide Deposits, "
Trans. ASME, Nov. 1949.
Krause, H. H., Levy, A., and Reid, W. T., "Sulfur Oxide
Reactions: Radioactive Sulfur and Microprobe Studies of
Corrosion and Deposits, " J. Eng. Power, 90 (Series A, No.
1), 38-44 (1968).
Sawyer, J. C., "Catastrophic Oxidation of Stainless Steels in
the Presence of Lead Oxide, " Trans. Met. Soc. AIME, 221,
63-67 (1961-63). -
Buckland, B. 0., and Sanders, D. G., "Modified Residual
Fuel for Gas Turbines, II Paper No. 54-A-246, 1954 ASME
Annual Meeting.
Newby, W. E., and Dumont, L. F., "Mechanism of Combus-
tion Chamber Deposit Formation with Leaded Fuels, " Ind.
Eng. Chem., 45 (6), 1336-42 (1953). -
Duzy, A. F., and Walker, J. B., "Utilization of Solid Fuels
Having Lignite Type Ash, " Paper presented at the Lignite
Symposium, Bismarck, N.Dak., 30 April 1965.
Bishop, R. J. I Cliffe, K. R., and Hangford, T. H., "Con-
densation of Sodium Chloride from Flue Gases, " BCURA
Research Report No. 359, August 1969.
A-29
-------
I
APPENDIX B
STATE OF THE ART SURVEY
I
,
i -
-------
1.
INTRODUCTION
\
The purpose of this appendix j s to provide an information compilation
that will describe the state-of-the-art, economic aspects, and emerging
design characteristics of steam generators. Emphasis has been placed on
systems that operate with steam conditions that are compatible with turbo-
electric applications. '
. A brief review of the recent history in the development of the design-
technology is presented, and predictions offered as to the future direction
steam generator design will take.
Cost and performance data, covering ten different boiler configurations,
considered to represent the essentials of domestic practice, have been sum-
marized. Cost data' for European systems have also been organized and are
presented for comparative study. Because German practice furnishes an ex-
cellent cross-section of modern European steam generator technology, data
generated in that country have been used.
To demonstrate the relevance of utility- scale boilers and those suitable
for refuse-firing, a review of what may be considered the intermediate classes
of boilers has been documented. These are comprised of units which fire in-
fet:ior fos sil-fuels and waste fuels.
The nature of emissions produced in PQwer boilers constitutes a logical
topic for this appendix, as does the methodology practiced for their control.
This discus sion includes consideration of both extant and advanced systems,
and the impact that foreseeable air quality standards will have on this field
of engineering.
, The final topic presented deals with the state-of-the-art of utility-class
steam generators which are fired by refuse, either as the sole fuel or in com-
bination with conventional fossil-fuels. At the present time, there are no true
examples of such systems in the U. S. This review has therefore been con-
fined neces sarily to European experience; more specifically, to German units.
Information is presented on the design characteristics of five German plants,
together with performance-test data generated by the Technische tJber-
wachungs Verein (TtJV).
II.
SUMMAR Y AND CONCLUSIONS
In maintaining pace with the exponential increase in energy demand,
the evolution of power-boiler design has been fast-paced and dramatic over
the past several decades. New engineering, fabrication, and operational
developments have profoundly influenced design-practice, as has fuel cost
and the consequent need to accolnmodate lower-grade fuels. Unit sizing
has reflected industry's reaction to power-demand pressures; 1200 and
1300 MW units are now being built and 3000 MW units can be expected by
B-1
-------
the year 1987. In the drive to achieve increased unit capacity, steam con-
ditions also underwent a steady increase. The constraints posed by operation
in the super critical region have now resulted in a trend or return b subcritical
units of the natural circulation type.
This trend, however, has not been followed in Europe, where the once-
through boiler predominates. In spite of this and other differences, it can
still be said that European boilers reflect rather closely the best odesign
practices used in this country.
In considering present and future generation power boilers as possible
convertible systems for the combined-firing of conventional fuels and refuse,
certain problems must be faced. Because of the steady increase in unit size
and the thermal fluctuations caused by variations in the calorific value of
refuse, the amount of the latter to be fired, in proportion to the regular fossil
fuel, will probably be limited. In the case of coal, at least, the practices
now often used in transporting the fossil fuel may have an important effect on
refuse haulage costs. A present trend in new unit construction is to locate
power-boilers close to coal-mining areas. Because of new transmission-
line fabrication techniques, it is cheaper to conduct electricity to the use-
point than to bring coal there from the mine-mouth. Thus, the future use
of retrofitted power plants for refuse-firing may well require the use of
older units, which are reasonably centralized, or the consideration of
advanced concepts of long-distance refuse conveyance.
In terms of the design of units to be used specifically for combined-
or refuse-only-firing, European experience has shown that the engineering
concept is practical. Units are now in operation which provide steam con-
ditions that are consistent with conventional power-boiler characteristics.
This has not resulted in the serious corrosion problems expected by many,
although a greater corrosion nuisance does apparently exist than when
firing with fossil fuels alone.
The direction of current U. S. designing, which will shortly result in
the first combination-fuel turbo-electric boiler, is to suspension-firing of
the shredded refuse. Although the principle has been successfully demon-
strated with other waste fuels, its application to refuse-firing should be
carefully monitored. This step represents a leap beyond the technology
now practiced in Europe, where raw refuse is fired on agitating grates,
or, at most, only bulky items are proeviously reduced in size. Indications
are that the firing of ground refuse in suspension, or even on an agitating
grate, will result in faster burning rates, better burn-out, and a reduction
of ash- bulk.
The air pollution control devices now in popular use in Europe are
almost exclusively aligned to particulate removal. The system favored
for this function is the electrostatic precipitator. Because of the low
sulfur-content of the coal used in Europe, there is less concern regarding
B-2
-------
sulfur oxides emission control. In this country, low sulfur fuels are not as
available; thus, a different emission control problem exists. It is obvious
that the advanced processes, now in development and in early industrial
application, for the control of emis sions of sulfur oxides from conventional
power plants, will also have to be considered for combined-fired boilers.
III.
STEAM GENERATORS
".
A.
HISTORY AND TECHNOLOGY
1.
Historical Development
The progres s in the development of fos sil fuel fired power
systems since the days of Thomas A. Edison and his contemporaries has
been spectacular. Steam conditions have increased from about 100 psig
and saturated temperature to superheat and supercritical pressures. Unit
sizes have grown from around 100 kw to the 1, 500,000 kw range. The
Edison Plant, Pearl Street, New York, in 1882 had a heat rate>',' of 138, 000
Btu/kw-hr. Today's plants have heat rates approaching 8,500 Btu/kw-hr.
In the first half of this century, advances were in the form
of a gradual evolution, setting the groundwork for the explosj on of technology
that occurred during the second half of the century. By 1937, the general
trends in steam generator design, which had long been accepted practice,
were listed (Ref. B-1) as follows:
.
Adoption of superheaters and economizers.
.
Substitution of water- and steam-cooled furnace
walls for refractory surfaces.
8
Removal of coal firing equipment from the inside
to the outside of the furnace~<*.
.
Progressive increase in the SlZe of individual
units.
.
Progressive increase in steam pres sures and
temperatures as boiler materials and manu-
facturing techniques improved.
.
Use of steam separators to prevent carry-over
of water to the superheater and turbine.
~~ Speciality terms are defined in Appendix E.
**The use of pulverized fuel firing systems became
their initial trials in 1919 (Ref. B-2).
almost general since
B-3
-------
The above trends, although described many years ago,
applied only to non-reheat, natural circulation boilers producing less than
1,000,000 lb/hr of steam under conditions of about 1500 psig and 900oF.
In 1937 the first steam generator with a design pres sure above 2000 psig
was developed and by 1939 the steam pressure had reached 2335 psig (Ref.
B-3). The technology explosion began in the post- WW II years and advanced
rapidly. By 1952, the trends observed (Ref. B-4) were as follows:
''';
.
Designs accommodate lower grade fuels
without economic penalties.
.
Cycle efficiencies improved to offset
increasing fuel, labor, materials, and
construction costs.
.
Feedwater treatment improved.
.
Evolution of combined and forced circulation.
.
Pressurized combustion.
.
Combustion of crushed coal.
.
Development of "quick- starting II techniques.
.
Introduction of welded panel-walls.
.
Excursion into the high pressure domain.
These trends, which are discussed below, still operate
at the present time.
a.
Fuels
The expanding power demands have neces sitated
that less desirable fuels be burned. This has included lower grades of coal
and also the use of imported oil crudes containing vanadium and sodium.
b.
Cycle Efficiency Improvements
During the immediate post-war period, stearn con-
ditions of 2400 psig /l OOOoF were being used. A graphical recounting of
stearn pressure and temperature increases up to and including 1955 are
illustrated in Figure B-1. Various techniques of superheating we re being
employed and reheating of steam had become the norm of the indus t.ry
(Ref. B-5). Regenerative heating, an attempt to minimize the effect of
the irreversibilities of the Rankine cycle, was also widely practiced.
B-4
-------
10,000
5,000
-------
In 1952, unit sizes of 200,000 kw were in operation;
by 1953 units of 250, 000 kw were on order (Ref. B - 6), and units of 300, 000 kw
were predicted (Ref. B-7). Because the limits of steam generator efficiencies
had long been achieved, the search for improvements in cycle efficiency was
concentrated on prime movers (turbines) and accessory equipmeI;lt. Further
increase in the unit size of the steam generator (and, thus, cycle efficiency)
awaited the development of the 3600 rpm turbine (Ref. B-8).
A comprehensive treatise on steam turbine develop-
ments was given in 1954 by Franck (Ref. B-9).
c.
Feedwater Treatment
As steam pressures and temperatures were increased,
new specifications for water quality had to be developed. This was especially
necessary for units operating near or above the critical pressure. Experi-
ence showed that water of exceptionally high purity was necessary in order
for large steam generator-turbine units to perform with high availability.
d.
Circuitry Evolution
As later discussed in further detail, the natural
circulation steam generator was joined, although not supplanted, by other
types of boiler circuitries. These included the forced circulation and the
various types of "once-throughl' designs. While these newer systems of-
fered a modest gain in efficiency, drawbacks existed which tended to make
the natural-flow circuit a still very attractive configuration.
e.
Pressurized Combustion
Three basic methods of firing developed: natural-
draft, balanced-draft, and pressurized. In natural-draft furnaces, no fans
are used; in balanced-draft systems, both a forced-draft and induced-draft
blower are used; in a pressurized system only a forced draft fan (handling
cool air only) is used. A savings in total fan horsepower of approximately
20 percent is thus realized in pressurized furnaces. However, the latter
require particular design attention with respect to furnace tightnes s, since
outward leakage of furnace gases cannot be tolerated. Gas tight protection
must be provided at literally hundreds of places, including observation
ports, air heater seals, damper seals, doors, burners, soot blowers,
and certain parts of the pulverizers. The advantages implicit in pres-
surized firing are better realized with ash-free fuels such as natural
gas and oil.
f.
Combustion of Crushed Coal
The first commercial cyclone-burner firing crushed
coal was installed in 1944. By 1954, twenty-five such boiler units had been
placed in service (Ref. B-I0). The main advantages of the cyclone furnace
were the elimination of coal pulverizers and reduction in the carry-over of
fly ash.
B-6
-------
:, - ':'/",'-,.
", .."'-' :"'. '~-
. " "
. -=': ~.' ,¥" I>~'; "'.:~:' "";",
g.
Quick-Starting Techniques
J Much of the work in developing more rapid start-up.
and shut down techniques was done by several utility companies. In order
to complt with these techniques, steam generator designs had to include th~
following features:
.
Drainability of steam and water surfaces.
.
Wide range of steam temperature controL
.
Elimination of rolled joints (through use
of all welded construction).
h.
Welded Panel- Walls
Perhaps the single most dramatic development of
the second half of the century was the welded panel-wall. The panels. con-
sist of a number of tubes joined together by a process of fusion welding.
The tubes are spaced about three-eights to one-half inches apart by means
of bars, which are then fused to the tubes to form a continuous metal fur...,
nace lining as shown in Figure B-2. The first commercial installations.
having welded furnace walls went into service in 1953 (Ref. B-ll and -12)
and 1955 (Ref. B-13).
Panel-wall construction, accomplished in the shop
with rigorous quality control, has led to considerable design simplification,
improved techniques of field erection, and significant cost savings. This
type of construction eliminated the need for an inner furnace casing since
the welded wall forms its own casing, as shown in Figure B-3. Membrane
or fin-tube walls, as they are also called, made possible the economic
utilization of supercritical forced circulation and pressurized combustion.
The advantages of welded waterwalls and radiant superheaters were com-
bined by relocating radiant superheaters as full length or partial division
walls.
A generation of units also appeared (Ref. B-14) in
which radiant superheaters comprised the walls of the furnace. The tubes
of these sections can have tube metal temperatures of up to 1000oF. It
has been shown that in burning refuse, corrosion may well occur at tube
metal temperatures of 7500F and above. Thus steam generators of this
type may not readily lend themselves to modification for the purpose of
refuse burning.
1.
Excursion into the High Pressure Domain
During the 1950' s, when only a few of the largest
units within power plants exceeded 300 MW, it was predicted by even op-
timistic observers that unit size (power capacity) had reached a plateau
B-7
-------
a
FIGURE 8-2. SECTION OF WELDED PANEL-WALL
B-8
-------
FIGURE B-3. TYPICAL EMPLACEMENT OF WELDED PANEL-WALL
B-9
-------
beyond which few utilities would venture. Instead, it was suggested that
the heat-rate gain available from operating at increased pressure and
temperature would far outweight the advantages of mere size expansion.
An excursion thus began into the construction of units operating at steam
temperatures of 1050-1100oF and above (Ref. B-15). Such plants were
the Kearny, Bergen, and Mercer Generating Stations, which operated at
steam conditions of 2400 psig / 11 OooF / 1 050oF. Special interest was at-
tached to two units of this era because the steam pressure approached
5000 psig. One unit of 125 MW was at the Philo Station (start-up March
1957) with steam conditions of 4500 psig/1l50oF with a double reheat to
10500F and 1000oF. The other was the Eddystone Station (start-up 1959)
with two units having steam conditions of 5000 psig/l200oF with a double
reheat to 1050oF. In Germany, where once-through design had been in
use only for sub-critical pressures, the first supercritical unit was a unit
of 85 MW at the Huels Chemical Works (start-up November 1956), having
steam conditions of 4520 psig / 11120F with a double reheat to 10400F
(Refs. B-16 and -17).
--
These breakthroughs into high pres sures and tem-
peratures proved, however, to be only excursions. Today, even though
supercritical pressures in the 3600-3675 psig range have become common-
place, they are matched by steam temperatures which rarely exceed 1000oF.
Furthermore, the predicted leveling off of unit size did not eventuate. By
1966, more than half the generating capacity on order was to be produced
by units of 500 MW and above.
What had occurred during the preceding decade was
a reappraisal of the relationship between unit and plant size, and total sys-
tem load. The arguments favoring the development of larger units were:
(1) a reduction in generating costs; (2) the development of widespread utility
system interconnections; and (3) a slight increase in efficiency*. The prin-
cipal factors that implemented the trend to greater unit-size were the ad-
vances previously described. Of these, the most significant were the use
of welded walls for enclosing the combustion zone and the availability of
superior materials for use in the superheater and reheater tubes, the most
critical heat absorbing surfaces in modern boilers. The choice of alloys
for these sections has centered on chromium-molybdenum, with austenitic
steels being favored in the finishing sections (Ref. B-15). Rapid advance-
ments in steam generator, turbine, and accessory equipment sizes also
supported the trend towards larger units (Ref. B-18).
A case history demonstrating this trend is the
experience of the American Electric Power Company. The success of
Philo 6, first operated in 1957, promoted it as the prototype for super-
critical pressure and double-reheat units. Two 475 MW supercritical
*An increase from 300 to 1000 MW results in a reduction in heat rate
of 1/2 to 1 percent.
B-I0
-------
units at Breed and Philip Sporn 5 were first operated in 1960. The sound
operation of these units, and the solution of a number of lesser problems
that arose, gave confidence to the direction taken. Tanners Creek, first
operated in 1964, was a 600 MW unit. Cardinal 1 and 2 were again 600
MW units, but incorporated two significant changes. These represented
the move from cyclone, wet bottom firing at Tanners Creek to pulverized-
coal, dry-bottom firing at Cardinal, and from an 1800 rpm, four-flow, low
pressure section at Tanners Creek to a 3600 rpm six-flow arrangement at
Cardinal (Ref. B-19). Big Sandy 2 was an 800 MW unit, which represents
a 33% increase in size over Cardinal (Refs. B-20 to -22). These units
were duplicated at Mitchell 1 and 2, and Amos 1 and 2. New orders were
recently placed for 1200 MW units. The size-leap of this decade has also
resulted in the order for two 1300 MW units for the Cumberland Steam Plant
of the Tennessee Valley Authority (Ref. B-23). According to recent pre-
dictions, this trend in unit-size increase will continue such that the maxi-
mum size unit installed in 1987 will be 3000 MW (Ref. B-24). This same
trend has also been the experience of other countries, notably the United
Kingdom (Refs. B-25 to -28). .
2.
Steam Generator Design
a.
Basic Circulation Effects
In the natura.l circulation steam generator, the
pumping head is provided by the density difference between the saturated
liquid in the unheated downcomer and the steam-water mixture in the heated
risers, as shown in Figure B-4A. A separating drum is required to pro-
vide the recirculated saturated liquid to the unheated downcomers and
saturated steam to the superheat inlet. Inherently, this unit has been
proved to be suited only for subcritical pressures and generally is operated
at or below 2850 psig (Ref. B-29).
In controlled circulation (Figure B-4B), a recir-
culating pump is employed to insure sufficient pumping head for the proper
cooling of furnace circuits. As the pressure approaches the critical pres-
sure of 3206 psia, the difference in density between water and steam is
reduced (as shown in Figure B-5) to a point where natural recirculation is
impossible; a mechanical means of fluid circulation, such as a pump, is
then required (Ref. B-30).
The forced circulation or "once...through" design
is European in origin; its general application and use in the United States
is comparatively recent (Ref. B-31). A unit is generally considered once-
through if it does not employ recirculation at full load. A highly simplified
representation of the once-through principle is given in Figure B-6. Typi-
cal boiler fluid temperatures are shown in Figure B-7. The three basic
configurations of once-through steam generators are shown in a simplified
form in Figure B-8.
B-ll
-------
DOWNCOMER
(SAT. WATER)
!
td
I
N
SATURATED STEAM
SEPARATING DRUM
RIRR i
A: NATURAL CIRCULATION
HEAT
INPUT
SATURATED STEAM
SEPARATING DRUM
DOWNCOMER
(SAT. WATER)
!
r
RISER
RECIRCULATING PUMP
B: CONTROLLED CIRCULATION
FIGURE 8-4. BASIC CIRCUITS FOR ACHIE.VING RECIRCULATION AT FULL LOAD
HEAT
INro'i'
- ORifiCE
-------
1:
-
CD
..I
~.
i
&AI
C
tJj
I
........
IN
80
60
40
<:
20
SATURATED STEAM
o
o
1000
2000
30-00
/ CRITICAL POINT
~... .. I SUBCRITICAL
~
PRESSURE, PSIA
4000
!iOOt)
FIGURE B-5.: EFFECT OF PRESSURE ON DENSITY OF STEAM A~b WATER
-------
~ STEAM
~
~
HEAT
~
..
PUMP
~ FEEDWATER
FIGURE 8-6. PRINCIPLE OF ONCE.THROUGH STEAM GENERATOR
B-14
-------
800
u..
0
"-I
at:
::)
t:d ~
, at:
...... t
lY'
"-I
~
600
DRUM TYPE
2500 PSIG
ONCE THRO . G ' ,
2500 PS G ,
: 500 PSIG
1000
...
a: a: a:
a: "-I a: w I!C w
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N « CI: N a: N «
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~ Cl:fI) :t ... :IE a:fI) % ~ «en :l: i
161'" a: « 0 Wd a: 0 w'" IX:
Z "'''' 161 161 2 ~..J 161 I!!
-------
,....-- :,1 -, --,
I ""-, - I
I I I 1
I I I I RECIRCULATED I I
, : I I FLOW (ONLY WHEN I I
I I AT LESS THAN 60% 1 I
I I I I OF FULL LOAD) I I
I I 1 I a:: 1 a:1
~I II.!
I I 1 I II
I I I I i:
I I I I I:
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RECIRCULATING
PUMP
FEED
VALVED CONTROL
OF FURNACE
FEED CIRCUITS
SULZER DESIGN COMBINED CIRCULATION DESIGN BENSON DESIGN
CONTROLLED
POINT IN
CIRCUITRY
MIX LOCATIONS
FIGURE B-8. ONCE-THROUGH BOilER SYS' : ~ S
-------
The Sulzer design is primarily a once-through unit
that provides a fixed point in the fluid circuitry for blow-down or control.
It may be designed to operate either in the subcritical or super critical
region. The subcritical design utilizes a steam-separating system fixed
at a point where the entering fluid is 95 percent steam. The separated
liquid is treated as blow-down and is fed back to the external pre-boiler
'cycle. In the supercritical design, a transitional zone is required where
circuit temperatures can be monitored and controlled so that maximurri
design values are not exceeded. Each of these designs employs I'valvedl'
furnace-circuitry and a control system to proportion fluid to the circuits,
as shown in Figure B-9.
The combined- circulation design employs a fluid
recirculating-pump for low-load operation of the furnace. Basically, this
design is a Benson type circuitry modified by incorporating a recirculating
loop and pump. Up to approximately 600/0 of load, th'e recirculated- and
throughput-fluid is used to cool furnace circuits; from this point to full
load, once-through operation of the furnace circuits is used.
, The Benson once-through design for either sub-
critical or supercritical operation is characterized by the complete absence
of any steam separating drums or fluid recirculation. Feedwater is con-
tinually heated to final outlet steam temperature in a single continuous
flow-path. The difference between subcritical and super critical Benson
designs is the arrangement of the circuits. Figure B-IO shows the ar-
rangement of the circuits for a subcritical and Figure B-ll for a super-
critical system.
It will be noted that the basic circuitry consists
of heater upflow tubes and unheated downcomers as in natural circulation
systems. The main difference between the two is the circuitry within the
furnace. For the greater pressures of supercritical once-through designs,
smaller size tubes are used. However, the disadvantage of using a greater
number of tubes is compensated for by an increase in the allowable heat
absorption. .
Present designs of natural circulation and once-
through boilers have evolved to a point of standardization that the structural
supports setting and insulation, and external appurtenances, as shown in
Figure B-12, are now quite similar.
Although the various forced-circulation systems
were employed in Europe earlier than in the United States, it must be pointed
out that European unit-sizes and steam-cycles were quite different from those
used by the United States central-station industry. In addition, many aspects
of boiler design, particularly those relating to furnace wall-enclosures, were
based on markedly different concepts. In Europe, tube-systems were tied
B-17
-------
1ST SPRAYS
STOP VALVES
BYPASS
VALVES
2ND SPRAYS
STEAM FLOW NOZZLES
FEED CONTROL
VALVES
FURNACE
CONVECTION
PASS
WATER
~ V INLETS
I~
PRESS
DIFF
VAL\(ES
FIGURE 8-9. SULZER ONCE-THROUGH STEAM GENERATOR
B-18
-------
- HEATED TUBES
-- -- UNHEATED DOWN COMERS
b:1
I
......
..J)
...
ECONOMIZER
,«::7\
I
I
I
I
I
FURNACE
PASSES
I
I
I
I
I
~~J
I~~
I
I
I
I
I
I
I ".....0- ,- . . I
I. .. I
irls i
L ~ C=H=tf
I ED E311!:3
I
PLATENS
OR
DIVISION
WALL
I
~
PEND
CONY
SH
FIGURE B-10. BENSON CIRCUITRY FOR SUBCRITICAL SERVICE
-------
HEATED TUBES
UNHEATED DOWN COMERS
----
,--, ,WI, ,-~
I I I "
I I I I
I I I I pQ
I I I
DIYI 10 N UlNA
tJj WALL I PASSES I CONY
I I I
['V I SHTR
::..., I I
ECONOMIZER I I I C ORll::>
I
. I CONY =>
I I CSHTR
I I I bJ~
I I i
l__' I .
,- ,,-
FIGURE 8-11. BENSON CIRCUITRY FOR SUPERCRITICAL SERVICE
-------
NATURAL CIRCULATION
ONCE-THROUGH
DO.
Do
c:::J r::J
IJ:1
I
N
~
FIGURE B-12. STRUCTURAL SIMILARITIES OF MODERN BOILERS
OPERATING BY DIFFERENT PROCESSES
-------
back through the brick to the steel supporting-structure and were designed
to move (in response to thermal variations) relative to the surrounding brick
wall. Because of this comparative freedom for expansion of tube systems,
circuits could be and were designed with highly individual shapes and func-
tions. The various types of basic "meandering" tube arrangements are
shown schematically in Figure B-13 and a typical furnace arrangement is
shown in Figure B -14. Both the Sulzer and Benson boilers employ such
tube arrangements in the high absorption areas of the furnace.
While these forced-circulation units became rather
common in Europe, their late application in the United States was more a
matter of economics than technology. Here again, the welded-wall con-
struction was a major factor for the adoption of forced-circulation in the
United States and for not using the European "meandering" tube-arrange-
ments.
German power station practice is characterized
by wide use of the Benson and Sulzer cycles, lower-grade fuels, and slag-
tap furnaces. Meandering furnace-tubes allow variable pressure operation
and German utilities consider this superior to constant pressure operation
as practiced in the United States. The majority of thermal power plants in
Germany are limited with respect to space and water resources. Because
of these limitations the plants must resort to recirculation of cooling water
and cooling towers are more widely used than in the United States.
b.
Typical Design Characteristics
Most of the boilers of interest to this study are of
the natural-circulation type. In terms of size, units in the nominal range
of 50 - 100 MW can be considered small. This size of unit finds applica-
tion in large industrial plants and small utility or municipal power stations.
Final steam temperatures ranging from 7000 to 10000F and operating pres-
sures ranging from 600 to 1800 psig are typical for this category. Steam-
£lows are of the order of 500, 000 to 1,000,000 lb/hr. Figure B-I5 shows
the arrangement of boiler equipment in a unit in this size range operating
at steam conditions of 1500 psig and 1 OOooF. It is noted that only 29% of
the total heat absorbed by the generator is required for superheating the
steam. Units near the 100 MW size may have reheaters.
The furnace is completely water-cooled. The super-
heater is of the all-convection type and is divided into two or more sections.
Temperature control is accomplished by water spraying between sections of
the superheater. The economizer is located in the heat recovery area, im-
mediately after the superheater. .
This unit is designed with sufficient furnace-volume
so that combustion is complete before the gas enters the convection surfaces.
The furnace water-cooling surface must have sufficient area to reduce the
B-22
-------
I.~
L'-- -
o.
~ _::.
VERTI CAL LOOP
HORIZONTAL LOOP
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", ,
" ,
))~'t
I I
RISER- DO\VNCOMER SYSTEM
SIX SECTIONS WITH 4 DOWNCOMERS EACH
,
" " \. \
, \ \
\ \
\ \
,
\
, I , ,
, \ \
\ \ \
\ \ \
\ \ \ \
\ \ \
\ \ \
\. ,
\ \ \
. . , I
-r-
II I I 1'1 \1 L=:::.
\ \ \ .\ \ \ - - - -
,'\\\'\\
\\\ \\\ \
\\\, \\\\\
\,\ \'\ \'
\\\\ \\ \\,\
\ ,.\ '\, \ \ \
,\,\'\\" \
I I , , , I . I I. I I I
COMBINATION LOOP TYPE AND RISER - DO'lJNCOMER SYSTEM
PARALLEL RISER- DOWNCOMER SYSTEM
FIGURE 8-13. VARiOUS TYPES OF ONCE-THROUGH EVAPORATORS
B-23
-------
! OUTLET
tP
I
tV
~
I t
I t ' I
I I
I j
I I i
I
I ~ 1-::. - I'
- J
-- " -. -
rr- ---fl';:: ... --I . .
.~
: . . ~
I
: t - . -
I .' .
, + - . .~
I
I
: ""'"
0 0 0 0 0 0 . :
0 0 0 0 0 0 i
0 I
0 0 0 0 0 I
I.
; !~ :
' :
--
" I / "/ ~ /7
"\. .
I / '/
" . '\: ~\ /7
/ ./
" 7/ " -~~~ -z:/
( -. -I T I " 77
J .,. . . ,
'Ii T~ ~..- -.J ill TJ
L 81
INLET
FRONT WALL AND RIGHT SIDEWALL
REAR WALL AND LEFT SIDE WALL
: GURE 8-14. MEANDER-STRIP EVA )0 ~ATOR FOR FRONT WALL : ~ \lG
-------
tJj
I
N
\JI
100%
SUPERHEAT
29
ABSORPTION
71
STEAM
GENE~ATION
0%
% TOTAL ABSORPTION
REQUIRED FOR FULL
STEAM TE M PERATURE
ALL BANK-TYPE SH
CONVECTION SH
~ SPRAY
D- ECONOMIZER
ALL WATER-
COOLED FURNACE
FIGURE 8-15. TYPICAL CONFIGURATION OF SMALL (50 - 100 MW) POWER BOILER
-------
temperature of the products of combustion below the point at which objec-
tionable slag-accumulations will occur on the convection-surfaces.
The larger units, in the 100-400 MW size, are
usually of the reheat type. Figure B-l6 illustrates the arrangement of
such a unit having steam conditions of 2400 psig /10000F at the super-
heater outlet, and 10000F at the reheater outlet. It will be noted that
about half of the total heat absorbed by the unit is required for superheat
and reheat. This figure shows a unit designed entirely with convection-
type superheater and reheater.
The superheater, which typically consists of several
sections, can include a platen for minimizing slagging difficulties, a pen-
dant section in the high gas-temperature zone, and a large bank in a lower
temperature zone. The reheater is located between two sections of the
superheater to economize on space. The design of a high-pres sure reheat
unit can be improved by using a radiant superheater in combination with a
convection superheater. Figure B-17 shows such an arrangement. It will
be noted that, in the radiant superheater, the steam temperature decreases
as the steam-flow increases, whereas in the convection superheater gas
temperature and mass velocity increase with steam-flow. The combination
of the convection and radiant superheaters thus produces a relatively flat
steam-temperature characteristic for a wide range of loads. This obviates
the need to resort to high furnace exit-gas temperature, exces sive desuper-
heating, gas recirculation~' or manipulation of burners to accommodate load
variations.
Research and experience have shown that corrosion
and oxidation take place in zones where the gas and tube-metal temperatures
are both high. It is possible to minimize these problems by arranging the
surfaces so that the highest metal temperatures are in location of low gas-
temperatures and, conversely, low metal-temperatures in location of high
gas-temperatures. As shown in Figure B-18, where the numbers on the
curve refer to the indicated positions in the boiler, all heating surfaces
are located in safe zones. Relatively low-temperature steam flows in the
radiant superheater, a zone of high gas-temperature and heat absorption.
The higher steam-temperature sections of the superheater and reheater,
on the other hand, are located in cooler gas zones.
The relationship between heat release rate and heat
absorbed was studied in a program sponsored by the ASME (Ref. B-29). In
this program, measurements were taken of furnace-face temperatures of
water-wall tubes at points uniformly spaced in the furnace-walls to deter-
mine the thermal distribution pattern in the various walls of the furnace.
Figure B-19 shows the unfolded elevations of the four walls of a boiler.
The average 6t value for the test is indicated at each point of measure-
ment. Isotherms are shown on the various walls to connect points of
equal rate of heat absorption at each point in terms of Btu/hr-ft2 on the
B-26
-------
100°/0
AS SORPTION
tt:J
I
N
-J
0°10
51
SUPERHEAT
& REHEAT
49
ST.EAM.
GENER:ATION
% TOTAL ABSORPTION
REQUIRED FOR FULL
STEAM TEMPERATURE
ALL BANK-TYPE SH 8RH
PLATEN SH
"-
CONY SH
REHEATER
CONY SH
ALL WATE R-
COOLE 0 FURNACE
FIGURE B-16. TYPICAL CONFIGURATION OF INTERMEDIATE-TO-LARGE
(100-400 MW) POWER BOILER
-------
SUPERHEAT
RADIANT a
CONV SH'S
INS ER IE S
="
b:J
I
N
00
RADIANT
SH
CON V SH"
RADIANT SH..../
o
50
S TEAM OUTPUT, 0/0
100
FIGURE B-17. TYPICAL CHARACTERISTICS OF COMBINATION RADIANT
AND CONVECTION SUPERHEATERS
-------
tJj
I
N
...J:)
LL
o
"
~ 3000
=>
.....
<[
a::
w
a..
~ 2000
w
.....
(f)
-------
ELEVATION ~~5I.CQOt.RY AR IN!E POSITION
!1040 92 .3 810 F"I,.1..L lCW)
ROOf 26.2 % EXCESS AIR
--22 ~ .1e 21 l' lO D
£30 ,,(1
.--24 l8 l8
~O SCREEN TUSES
!')I()' --33
!IOC'
--29 ~ Jill J:II ~ ~ 3;l
490-
--34
4eO
410' --24
460' --38
4~' --34
LEVEL..
440' "'VG. I:. T FRONT RIGHT REAR LHT
FIGURE B-19. FURNAce HEAT ABSORPTION IN STEAM GENERATORS
B-30
-------
projected area. Figure B-20 is a simplified graph showing heat absorption
in the furnace. It illustrates the variation of heat absorption along the length
of a radiant tube. It also provides the average absorption used for deter-
mining the average performance of the tube, and the maximum absorption
used for assigning the metal temperatures to be observed in the selection of
tube materials. The shapes of these curves depend on several factors, such
as type of firing and location of tubes.
c.
Fuel Firing
The physical and chemical characteristics of fuels
and their ashes, along with their burning characteristics, are primary
factors in determining furnace:-type, size, configuration, performance,
and detail. Some fuels foul the furnace and heating surfaces. This has an
effect on the heat absorption characteristics of the unit and can be of ex-
treme importance when clean and dirty fuels are used alternately. Some
fuels, when fired in combination, produce slagging problems that would not
exist if each fuel were fired alone. Combination firing also requires appro-
priate burner design to maintain proper flame clearance and preclude im-
pingement of the flame on the furnace walls.
With coal-fired units, a considerable variation in fuel
properties exists. Moisture, ash, other impurities, heating values, and
grindability are some of the characteristics of the coal that can influence the
boiler design. Being a solid fuel, coal requires a longer residence-time in
the furnace than do other fossil fuels to allow the combustion process to go
to completion. Residence time is a function of furnace volume and the dis-
tance from the burner to the superheater.
The function of fuel-firing equipment is to introduce
the fuel and air for combustion, mixing these reactants, igniting the mixture,
and distributing the flame and products of combustion. In the pulverized coal-
fired system (in the unit size-range under study), the coal is first processed
in a crusher and ground to a talc-like powder in a mill. These mills are
usually of the low or medium speed type. A typical coal-fired system with
a medium speed mill is shown in Figure B-2!. For units burning oil and
gas, these fuels are delivered to the burners with no intermediate steps
other than oil-preheat.
In the burners, the fuel is mixed with the required
amount of combustion air and sprayed into the furnace. The design of the
burner must be such as to promote a uniform distribution of the hot gas-
mass within the combustion chamber. Figure B-22 is a typical design of a
multi-fuel burner. Burners are usually mounted on the front and/or rear
walls, or in the corners of the furnace. Burners mounted in the corners
of the furnace are usually of the tilting type. This aids superheat tem-
perature-control. Each group of burners in a coal-fired unit is associated
with a particular mill.
B-31
-------
lIJ
t-
-------
b:J
I
W
W
fURNACE
............; .,
. ! , """,,),..! .
, II n}" ~ '
li-n;" , II ,J. ~.,.- J
:11'l3 ::II ,1,!I'I'
:, .:oJ n'l F( ;
11 I t=-,::,i i,ii! ' f: II'
1 rT ,I', ,'. ','
, : {::f' rl./, ,1;
! l,~ci!=;-_C_:l', ,,- J1P~ :. " I
'I mmm_,' I ., '\.. /. . . i ., ~
I: \\~::~:.~!~Jl(~: ::-::;i~/ -, ~
lL-==_~::~=~~=:_.i¥" I' II fQ-,.,=._~~",=>
-------
Oil GUN
OR
IGNITOR
\ ,-.
M6:°_mm
SECONDARY AIR
TERTIARY AIR
FIGURE B-22. MULTI-FUEL BURNER
B-34
-------
CyclQne- burner firing is a methQd used with suitable
cQals, usually .of the lQw-fusiQn, high-ash bituminQUs type. This furnace,
as shQwn in Figure B-23, has a water-cQQled, hQrizQntal cylinder in which
fuel is fired and cQmbustiQn is cQmpleted. The crushed cQal, apprQximately
95% .of which is sized at 1/4 in. .or less, is burned at very high heat release
rates (500,000 Btu/ft3-hr); gas temperatures .of 3, OOOQF and higher are de-
velQped (Ref.. B-32). Basically, this is a slagging furnace.
The case fQr a dry-bQttQm .or a wet-bQttQm (slagging)
furnace has been a matter .of QperatQr preference. In the 1940's, several
units in Ohio were built that fired bituminQus cQal thrQugh intertube burners
(Ref. B-33). Except fQrunits equipped with cyclQne units, nQ large slagging-
furnaces were then built until the 1950's, when a pair .of 300 MW units, each
with twin furnaces, were .ordered. AnQther pair .of similar, but slightly lar-
ger, units were put intQ service in 1960 at the Mercer Generating StatiQn.
In bQth plants the cQal was pulverized and fired thrQugh the frQnt wall.
In cQmparisQn tQ dry bQttQm furnaces, it has been
shQwn that slagging-furnaces have demQnstrated lQwer availability and higher
maintenance CQsts. Maintaining the integrity .of the refractQry lining fQr the
mQlten slag has been the main prQblem. Steam generatQrs with slagging-
furnaces, including cyclQne furnaces, are prQPQsed .only when the lQng- range
fuel supply has characteristics clQsely similar tQ thQse .of fuels which have
demQnstrated their suitability fQr cyclQne-firing (Ref. B-34). IrQnically,
the slagging-furnaces at the Mercer Generating StatiQn established several
efficiency recQrds. In 1961, fQr example, plant heat-rate, as reported by
the Federal PQwer CQmmissiQn, stQQd at 8,894 Btu/kw-hr, the lQwest in
the WQrld fQr a drum-bQiler, single-reheat installatiQn. The fQllQwing year
a recQrd .of 8,874 Btu/kw-hr was set (Refs. B-35 and -36). These units are
.operated, hQwever, at unusually high steam-temperatures. In recent years,
the trend .of the utilities has clearly indicated a preference fQr pulverized-
cQal firing with a dry bQttQm (Ref. B-3 7). One utility (Ref. B -19) "cQn-
firmed cQnclusiQns frQm an extensive study that led tQ rejecting the wet
bQttQm and accepting the increased capital CQsts .of the dry bQttQm as an
indispensible element in cQntinuity and lQW .operating CQst. "
. As suggested earlier, EurQpean experience has
differed in this area. Slagging furnaces have been widely used in Germany
and .other cQuntries because .of the lQwer CQst .of the steam generatQr and
ash disPQsal. A summary .of the EurQpean experience is included in the
appendix .of Reference B-38. In additiQn, extensive research has been
. carried .out .on the utilizatiQn .of slag as a by-prQduct (Ref. B-39).
B-35
-------
'."--y
/:
".
FIGURE 8-23. CYCLONE-FIRED FURNACE
B-36
-------
3.
Cost and Performance Data for Representative Designs
a.
Characteristics of Ten Selected Steam Generators
A total of 10 designs was selected to exemplify the
present state-of-the-art in this country in the capacity range of 44 to 400
MW. Of course, much larger units are in operation today, but units with
nameplate ratings exceeding 500 MW's were considered to be outside the
scope of the present survey.
The illustrative examples cover various fuels, de-
signs, and use of steam generators. The selection includes seven natural
circulation units, one controlled circulation, and two subcritical once-
through units. Three of the examples are gas-, two are oil-, and five are
coal-fired. Some of the units are designed to burn alternate fuels. Most
of the units have horizontal burners; one has tangential, tilting burners;
and one has a cyclone furnace. A summary of the performance of the 10
selected steam generators is given in Table B-l. Economic data on these
units is presented in the section which follows. A brief description of each
design is as follows:
Unit No.1 - (Fig. B-Z4)
This is the smallest size (44 MW) unit selected
for the study. It is a gas-fired steam generator having no reheat cycle. It
is of the top- supported type, with two drums and a baffleles s boiler bank.
Six burners are located in the front wall. This type of unit is generally
used for large industrial applications or for relatively small power- gene-
ration applications, such as for a municipality. Operating steam conditions
may vary considerably, but usually favor the 1300 psig and 9500F level.
Unit No.2 - (Fig. B-Z5)
This is a larger gas-fired, non-reheat unit
of almost twice the capacity of Unit No.1. The entire unit is supported
at the bottom. It has two drums and a baffled boiler. A division waterwall
1S located in the furnace.
Unit No.3 - (Fig. B-Z6)
This is a 100 MW central-station type steam
generator. It is a coal-fired, reheat unit. The four rows of intervane bur-
ners are suitable for burning pulverized coal or oil. This generator has
only one steam drum. Because of the addition of the reheater, the boiler
bank found in small units is absent. In a reheat unit, a greater degree of
evaporation is done in the furnace and convection area walls. This par-
ticular boiler has three stages of superheat, one of which is in the form
of a radiant wall extending the entire length of the furnace. The unit has
B-37
-------
TABLE B-1
SUMMARY PERFORMANCE OF TEN SELECTED STEAM GENERATORS
Unit No. 1 2 3 4 5 6 7 8 9 10
Unit Size, MW 44 81 100 158 200 230 245 300 327 400
Fuel Gas GMJ Coal Gas Coal Coal Coal Oil Coal Oil
Steam Flow, 103 lb/hr 500 756 804 I, 065 1,475 1,502 1,734 1,950 2, 300 2, 390
Pressure Superheater
Outlet, psig 1, 300 1,275 1,980 1,875 2,450 2, 591 2,486 2, 100 2,620 2,460
Temperature Superheater
0 950 950 1,005 1,010 1,050 1, 005 1, 000 1, 005 1, 005 1, 005
Outlet, F
Tempergture Reheater 1, 005 1,010 1, 000 1, 005 1,000 1, 005 1, 005 1, 005
Outlet, F
IJj Temperature Gas Leaving
I 0 1,810 2, 330 1,880 2, 365 1, 990
l.V Furnace, F 2,100 2,355 1,870 1,850
00
Temperature Gas Leaving
Air Heater, of 274 245 307 253 257 274 285 268 282
Draft Loss Total, In. H20 11. 90
Air Loss Total, In.H20 18.49 19.65 21.73 16.65 27.45 21.15 12.00 27. 56
Heat LibefationRate, 22, 300 39, 600 16,000 27,700 21, 000 16, 050 15, 900 24, 000 20,800
Btu/hr-ft
Boiler Efficiency, % 84.23 85.44 88. 26 85.23 89.27 88.94 89.32 88.92 88. 56
-------
BU
REGENERATIVE
AIR HEATER
,.~
roo,
SECONDARY
I'""'"'''''
~N
22'.III~'
FURNACE WIDTH
ID
po.
21'.8"'4"
FURNACE DEPTH
~=
/
49' - o'
fiGURE 8-24. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.1
B-39
-------
SUP[IIII[AT[II OUTL[T
i
IIJ
Ii
I
~ !II:
w .
....
~'"
"w
:ax
-~
~w
....
~
..
I,
, .
I
I
\
'-
/
///." / ,,/",1, ,'///. ///. ."//, /// /, /,
//,.' ///,
"/ '. /
36'.3"
'0
..
....
REGENERATIVE
AIR HEATER
'"
....
//
FIGURE 8-25. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.2
B-40
-------
I
1708'-6" I
-_..-.-._--
EL.
PENDANT SUPER
ATER OUTLET
ATER INLET
n
I , I I
; \ / I
AT CONTR
DAMPERS
BUR
GENE RAT V
IR HEAT R
--
FAN
44'-6"
44' - 0"
FIGURE 8-26. SELECT~D STEAM GENERATOR DESIGNS - UNIT NO.3
B-41
-------
a parallel pass arrangement of superheater and reheater convection surfaces
to facilitate steam temperature control. Heat recovery by economizer and
air heater follows the parallel pass.
Unit No.4 (Fig. B-27)
This is a 158 MW utility unit designed for gas
firing. In this unit, the radiant superheater-stage is composed of several
tube panels suspended in the upper portion of the furnace.
Unit No. 5 (Fig. B-28)
This is a 200 MW coal-fired utility generator.
It is of the once-through, subcritical, design. This type of unit has no drum
and differs from the natural circulation (drum) unit mainly in the circuitry
of the furnace walls. The coal pulverizing mills are of the medium-speed,
planetary roll and table type, which pulverizes fuels to any desired, uniform
fineness. The pulverized fuel is fired in burners arranged for opposed firing.
Unit No.6 (Fig. B-29)
This illustration shows a 230 MW, natural
circulation, coal-fired unit. The coal-burners are located in the front
walls. Again, mills are used to pulverize the bituminous coal.
Unit No.7 (Fig. B-30)
This 245 MW unit is of the controlled circulation,
twin-furnace design. It is similar to the one-drum, natural-circulation gene-
rator, except it has a pump to force the circulation of the water in the gene-
rator. The mills pulverize the coal, which is then exhausted to the burners.
These are of the tangential type and are located at the four corners of the
furnace. These burners can be tilted up or down and are useful in control-
ling the steam temperature over a wide range of loads.
Unit No.8 (Fig. B-3l)
This is a 300 MW unit specifically designed for
oil firing. It has a reheater-bypass for the control of steam temperature.
There are two radiant division-walls in the furnace and a radiant super-
heater-section located in a portion of the front furnace-wall.
Unit No.9 (Fig. B-32)
This illustration shows a 327 MW coal-fired
unit. In this installation, crushed coal is introduced at the burner end of
several cyclone furnaces located near the bottom of the main furnace. This
cyclone-firing is a method of burning low-fusion, high ash- content bitumi-
nous coals. The superheater and reheater sections in this unit are arranged
in series. Steam temperature control is frequently obtained by recirculating
gas from the economizer pass to the furnace.
B-42
-------
. ,
---_._----------~---------,--,-",------------ ~ _.--
._-_._.._--------_.._---_._..~
SPRAY CONTROL "~AD2R
'"
WAL
"
...
\
- I
","U r ,",en
I
i
I
I
I
'NLET
30'.'12"
FURNACE WIDTH
211'-1"
'URNACE DEPTH
i
i
: I
I
Ii
I
I
I
I :
I '
I '
\,
'--..
i j
11
.' .', ... ""'r'. ,/ ,- ,..
/./ ,/ /,','/...~ /'///',
-/: ~/ Tr
..'-0.
FIGURE 8-27. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.4
B-43
-------
!
, i
-~~
II
i i
I
!
, I 1/
I ,
! j/
I ,
II
~
fl. 179'-6
: I
')
i i
I
I
- ! ~--
j;- -
i I
Ii
I
i
//
- 1
I
I
I
-/--
ii/
c:=---'
30' - 0"
,n~r/-
/ ./ / .-
... .' /
, / /
FIGURE 8-28. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.5
B-44
-------
?
'",
ER
SUPERHEATER OUTLET
, '
J
: !
'0
'"
! !
ER INLET
BURN
P LVERrZER
EL.1I1I6'-0'
,~
,1-0.
42'-0'
3 e' - a"
FIGURE 8-29. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.6
B-45
-------
, PENDANT REHEATER
FINISHING SUPERHEATER
PLATEN SUPERHEATER
.- - - -.-
ECONOMIZER
REGENERATIVE
AIR HEATER
. . . ~ . . . .
.
.
o
50FT
FIGURE 8-30., SELECTED STEAM GENERATOR DESIGNS - UNIT NO.7
B-46
-------
~.. "! '
'.",
I I
I,
SUP~RHEATER
CONDE!jI ER HEADER
I
:<
UPERHEATER
HEADER
CQNVECTION SUPERHEATER
I I
i: ECON~l"ZER OUTLET
=,~, l I
. Sp~ERHEATER OUTLET
: i
:tEATER BY-PASS
R~ EATER OUTLET
i
Rit EATER
I
I
I
I . ~'"
EctiMIZER ~
RErEATER INLET
EJdNOMIZER INLET
L-
..11 LJ
"d1l!_.
I!
I,
\
I
1
,
REGENERATIVE
AIR HEATER
r-~J
I /--
1,...."- ",
~ "
~ '\ I --'/1- -
~. -_/ .--J STEAM AIR HEATER
f. D. FAN
-'-------- --~ ~- ~_. -
j l
~'
'1
-/1 r
I
"
.
1?
/ ., /. /
.' . ///, "
37'-1"
FIGURE B-31. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.8
B-47
-------
GAS-
TEMPERING
PORTS
I
I
I
I
I
179'-6"
GAS-
RECIRCULATI NG
FAN
! GAS
: : . OUTLET
.lt~~T
: :: ;
.' :
.1
~ -........... .r~.#.:J... ...... ~
29'-0"
"
27'-0"
24'-0"
24'-0"
28'-0"----:1
FIGURE 8-32. SELECTED STEAM GENERATOR DESIGNS - UNIT NO.9
B-48
-------
Unit No. 10 (Fig. B-33)
This is the larges t unit (400 MW) used for
this survey. It is a natural-circulation, oil-fired, steam generator. The
superheater has a front-wall radiant section in addition to a platen section
at the furnace outlet. a pendant spaced-tube section behind the platen, and
a horizontal convection-section in parallel with the reheater in the rear
pass.
b.
Economic Analysis
(l )
Cost Data~ Based on Ten Selected Designs
A convenient method of presenting capital
costs of these plants is by using the Federal Power Commission Uniform
System of Accounting. Major items in this system consist of the following:
F. P. C.
Code Number
Description
.-.
310
311
312
314
315
316
Land
Structures
Boiler Plant Equipment
Turbine Generator Equipment
Accessory Electrical Equipment
Miscellaneous Plant Equipment
Other Expenses
The sources used in determining the capital costs for the 10 units selected
for this study are References B-17 and B-40 to -42.
To develop Table B-2, a correlation was first
obtained between unit capacity and the various component costs. This was
done in the form of graphs and tabulations. Figures B-34 and B-35 show
these relationships for the boiler plant and the turbine generator plant.
Such costs as land and structures vary considerably for units of the same
size. This is understandable as land value and the type of structures needed
vary with the location.
The Boiler Plant Equipment costs (Code 312)
were further subdivided as shown in Table B-2. The main source of infor-
mation for the breakdown is the data of George (Ref. B-42). For example,
the feed-water equipment (Code 122) in George's study, cost $1,300,000
for the average unit he considered. This amount represents 7.9% of the
total cost of the boiler plant equipment. In a corresponding gas fired unit,
*Unless otherwise specified, the base date for all cost data in this report
is July 1969.
. B-49
-------
~
i I
I: I
I
I
, I
~~
I .......~
'i'...... ~~ ......RADIANT
! I
i ,
::I-----~L~~'J
: If " " " .~
I
,
i
,
i'
I
,
I
LL~~\,. HEATt
',I J I
/' /,"", -~ "
I ( ,.. D fAN I L----
, "Yi 'I
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FIGURE 8-33. SELECTED STEAM GENERATOR DESIGNS - UNIT NO. 10
B-50
-------
-- - -- --
" ~
TAB~E B-2
CAPITAL COSTS OF TEN SELECTED STEAM GENERATORS
Values In $1000 other than bottom line
Unit No. 1 2 3 4 5 6 7 8 9 10
Unit Size, MW 44 81 100 158 200 230 245 300 327 400
Fuel Gas Gas Coal Gas Coal Coal Coal Oil Coal Oil
310-Land & Land Rights 100 130 150 210 240 260 260 280 290 300
311-Structures & Improvements 850 I, 07 0 2, 650 1, 990 5,460 6,290 6, 690 3, 170 9, 010 4,350
312-Boiler Plant Equipment
120-Boiler & Accessories 1, 147 1, 600 3,430 3, 320 5,820 6, 300 6,540 6,030 7,600 7, 180
121-Draft Equipment 480 670 1, 185 1,385 2, 010 2,180 2,260 2, 360 2,620 2,800
122-Feedwater Equipment 372 525 682 1, 072 1, 160 1,255 1, 300 1,480 1, 515 1,755
123-Fuel Handling & Storage 1,010 1,720 1, 860 1,925 135 2,2'40 159
124-Fuel Burning Equipment 81 - 115 760 238 1,295 1,400 1,450 413 1,685 479
b:I 125-Ash Handling Equipment 233 397 425 445 60 $15 79
I
U1 .126-Water Supply & Treating 108 150 199 310 338 365 369 445 440 527
- 128-Boiler Instr & Controls 112 158 251 326 420 460 461 535 555 611
129-Boiler Plant Piping 450 632 900 1, 305 1,540 1,655 .1,700 1, 990 1,990 2,360
Total Boiler Plant Equip 2,7'50 3,850 8, 650 7,950 14,700 15,900 16, 450 13, 450 19, 150 15,950
314-Turbine Generator Equip 2,650 3,650 5, 600 7,650 8,950 9, 550 9,850 10,750 11, 150 12,400
315-Accessory Elec Equip 810 1, 030 1,450 1,450 1,950 2,120 2,210 1,650 2, 650 1,950
316 -Misc Plarit Equip 90 100 160 110 260 330 370 320 580 540
Other Expenses 1,690 2, 030 2,460 3,820 4,720 5,310 5, 650 6, 600 7, 120 7,980
Total Plant Cost 8,940 11, 860 21,120 23, 180 36,280 39,760 41,480 36,220 49,950 43,470
Unit Capacity Cost ($/KW) 203 147 211 147 182 173 168 121 153 108
-------
20
0
18 0 COAL
o
COIL
o GAS
16
0
14
C
12 0
o
CQ 0
o
....
10
C
8
6
o
2
50
100
150
200
260
300
350
400
PLANT SIZE, MW
FIGURE 8-34. BOILER PLANT EQUIPMENT COST
B-52
-------
10
8
o
CO
o
...
6
o
o
4
o
o
o
0/
o
o
o
o
o
o
o
REHEAT UNITS
- NONREHEAT UNITS
o
2
50
o
100
150
250
300
200
PLANT SIZE~ MW
FIGURE 8-35. TURBINE GENERATOR EQUIPMENT COST
B-53
o
350
400
-------
I
!
the feedwater equipment was assumed to cost the same amount, but with
relation to the cost of gas-fired boiler plant equipment this represents
13. 50/0 of the total.
An item, "other expenses, II is also included
in Table B-2. This item covers miscellaneous costs such as transmission
plant structures and equipment, indirect construction expenses, design
engineering, administrative expense, and other general expenses.
Energy costs are another important factor
to be considered in evaluating the economics of a steam power plant.
These costs are the sum of the operating expenses and the fixed charges.
The operation costs consist of the operating
and maintenance charges, and fuel charges. The operating and mainten-
ance charges include wages, supervision, maintenance, and repairs. The
fuel charges are a function 01 the plant heat rate, net generation, and fuel
cost- rate.
For this study, the values used for the various
factors making up the operation costs were derived mainly from the data
contained in References B-40 and B-43. A reasonable correlation was ob-
tained between operating expenses (exclusive of fuel) and size of unit. These
expenses vary with the type of fuel fired.
In the determination of fuel charges, it was
neces sary to establish values for plant factor, plant heat- rate, and fuel
cost-rate. The source of data was the same as for the operation expense
(Refs. B-40, -41, and -43). The plant factor, which can be defined as the
ratio of the average load to the rated capacity over a stated time period,
was found to be higher for coal-fired units than oil units, gas-fired units
having the lowest plant factor. Size of unit did not affect the plant factor.
From this investigation, it was decided to use plant-factor values of 70%,
60% and 50% for coal, oil and gas units, respectively.
A plot of net heat- rates vs size of unit for
different steam-cycles was made for the various units. Values for the
survey were then taken directly from this graph. Similarly, the cost of
fuel was investigated. Values per million Btu' s of $0. 25, $0. 32, and
$0.22 for coal, oil, and gas, respectively, were found to be representative
of costs in this country as of early 1969. The fuel charges were then cal-
culated from the capacity rating of the unit, ~ts plant factor, heat- rate and
fuel cost-rate.
Fixed charges for a steam power plant in-
clude costs of capital, depreciation, insurance, property taxes, State
and Federal taxes, and other smaller items. These fixed charges vary
B-54
-------
considerably from plant to plant. A few years ago the Federal Power Com-
rnission suggested that an annualization rate of 12.4% would represent a good
average. In view of the fact that interest rates have gone up considerably in
recent years, a value of 15% was selected as the fixed-charges rate for this
study. This rate. applied to the total plant costs shown in Table B-2, pro-
duced the fixed charges for the units selected.
Table B-3 provides a summary of the vanous
costs making up the total energy costs for the 10 units analyzed.
(2)
Cost Data Based on German Practice
Capital costs, steam generation costs, and
steam requirements of single - reheat steam power plants were supplied by
Siemens America, Incorporated. Figure B- 36 shows the capital costs of
power plants in the 150 to 600 MW range for plants designed for firing with
lignite, bituminous coal, and natural gas or oil. These costs are based on
waste~heat being dissipated by cooling towers and with make-up water being
obtained from a nearby river. Figures B-37 through B-39 give the total
generation cas ts for different full-load hours per year for 100 MW, 300 MW.
and 600 MW units and for three different fuel-types. The fuel costs used in
developing Figures B-3 7 through B-39 are for December 1969 and are low
rather than typical values. The conversion employed was based on a rate
of exchange of 27. 3 cents per German Mark (DM). The method of calcula-
tion used by Kraftwerk Union AG>:' is based on the computational sequence
shown in Table B-4.
Fuel costs are based on the lower or net
heating value of the fuels, which is general practice in Europe. In the
United States it is the general practice to use the higher heating value.
The following conversion factors when multiplied by European fuel costs
yield fuel costs in the same currency for the higher heating values.
Average HHV
Fuel (Btu/lb ) Fa cto r
Lignite 4,000-4,700 O. 70
Bituminous Coal 12,900 0.96
Oil 18,"300 0.94
Natural Gas 21,400 0.90
This conversion need only be applied to heat content of fuels and not trans-
ferred heat. In other words, the factors are applicable to net plant heat-
rates but not turbine heat-rates.
';'The European principal for Siemens America.
B- 55
-------
TABLE B-3
PLANT TOTAL ENERGY COSTS OF TEN SELECTED STEAM GENERATORS
Unit No. 1 2 3 4 5 6 7 8 9 10
Capacity, MW 44 '81 100 158 200 230 245 300 327 400
Fuel Gas Gas Coal Gas Coal Coal Coal Oil Coal Oil
Plant Factor 50 50 70 50 70 70 70 60 70 60
Plant Heat Rate, Btu/kw-hr 12, 700 11,800 10, 600 10,600 9, 550 9,470 9,420 9,400 9, 300 9, 280
6
Net Generation, 10 kw-hr /yr 192 355 613 691 1,225 1,410 1, 505 1, 575 2,010 2, 100
6
Fuel Cost, $/10 Btu's 0.22 O. 22 0.25 0.22 0.25 0.25 0.25 0.32 0.25 O. 32
tJj 1) Production Expenses, 103 $
I
V1 a) Operating and Maint. 140 200 322 328 535 600 630 700 804 900
0'
b) Fuel 539 923 1,625 1, 610 2, 920 3, 340 3,540 4, 730 4, 670 6, 200
2) Fixed Charges @15%,103$ 1, 340 1,780 3,280 3,470 5,450 5,950 6, 220 5,440 7,490 ~?20
3) Total Energy Cost, 103 $ 2,019 2,903 5,227 5,408 8, 905 9, 890 10, 390 10, 870 12, 964 13, 620
Total Energy Cost, mills/kw- 10.43 8. 18 8. 50 7.95 7.28 7.00 6.90 7.23 6.45 6. 48
hr
---- ----~_. ,->-
-------
150
,
[
>-
....
-
o
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a.. 125
-------
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en
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en
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en
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u
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~8
u
-
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-
U
L&.I
a..
en
",
Data Source-Kraftwerk Union AG
300
MW
600 M I¥
6
4
5
.103 Hrs/Yr - FULL LOAD
6
FIGURE 8-37. SPECIFIC POWER PLANT TOTAL ENERGY PRODUCTION
COSTS - LIGNITE
B-58
-------
13
Data Source- KraftwerkUnion AG
12
~
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I
~
~
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~ II
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A)
10.
11.
12.
13.
14.
TABLE B-4
KRAFTWERK-UNION COMPUTATION PROCEDURE.
FOR DERIVING ENERGY PRODUCTION COSTS
Amortization Costs
1.
Specific power plant capital costs
(derived from Figure 37)
2.
Total power plant capital costs
(AI x installed capability)
3.
Interest charges during construction (8% of A2)
4.
Taxes during construction (2% of A2)
5.
Total capital requirements (A2 + A3 + A4)
6.
Straight-line amortization (capital repayment in
17 years with 10% interest rate = 12. 7% of A5)
7.
Taxes (2% of A5)
8.
Insurance (0.8% of A2)
9.
Annual capital costs (A6 + A7 + A8)
Total power plant service load
Tranformer efficiency
Net power plant capability (installed capability
x All - Al 0 x All)
Net generation with either 4,000, 5,000 or 6,000
full-load hours per year
(A12 x 4, 000, 5, 000 or .6, 000 hours, respedively)
Specific amortization costs (A9 /AI3)
B-61
UNITS
DM/~ mstaHed
DM
DM
DM
DM
DM per year
DM pe.r year
DM per year
DM per year
kw
%
kw
kw-hr
Dpf/kw-hr
(100 Dpf = 1 DM)
-------
B)
C)
TABLE B-4 - Continued
Fuel Co sts
1.
Boiler efficiency (generally 93. 5% approx. )
%
2.
Pipework efficiency (generally 99%)
%
3.
Overall plant heat consumption calculated as follows:
Net turbine heat rate
BI x B2 x All (I -
AIO
Kcal/kw-hr
)
Installed Capability
4.
Net plant heat consumption corrected for partial
loading (by +5%, +3. 5% or + 2% at 4, 000, 5, 000
or 6,000 full-load hours per year, respectively
Kcal/kw-hr
5.
Dpf/kw-hr
Specific fuel costs (fuel cost x B4)
Fuel cost is taken at 4DM, 5DM, 6DM and 7DM per
million kilocalories for lignite, and at 7DM, 8DM,
9DM and lODM per million kilocalories for oil,
natural gas and bituminous coal.
Operational Costs
1.
DM per year
4.
D)
Annual compensation per man per year
(generally DM 25, 000)
2.
Personnel requirements
for unit size of
with oil or natural gas
with lignite or
bituminous coal
300 MW
80
100
600 MW
90
110
100 MW
70
90
3.
Annual operational costs (Cl x C2)
DM per year
Specific operational costs with either 4,000,
5,000 or 6,000 full-load hours p. a. (C3 A13)
DM/kw-hr
Intermediate Summation of Specific Costs
E)
Addition of specific costs for amortization, fuel and operation
(A14 + B5 + C4).
Dpf/kw-hr
Overhead Expenses and Lubricants (2% of D)
Dpf/kw-hr
F)
Specific Power Plant Total Energy Production Costs
(D + E)
Dpf /kw -hr
B-62
-------
A detailed breakdown of the capital costs for
200 MW and 400 MW boilers designed for bituminous coal and for natural
gas or oil is presented in Table B-5. These costs reflect typical recent-
day domestic German costs, converted into U. S. currency for boiler plant
equipment as defined by the Federal Power Commission under the 19 items
of Electric Plant Account 312. No costs are given for Items 15 and 19
since neither stokers nor wood fuel are employed with conventional thermal
plants of the sizes under consideration.
Table B-6 gives a breakdown by job classifi-
cation of the personnel requirements of a typical 300 MW coal-fired power
station. The grand total of 98 people can be considered an average for
German conditions and can be reduced if such a plant is automated.
4.
Power Generation with Special Fuels
The previous discussion of steam generators has been
largely directed to systems firing bituminous coal, oil, or natural gas.
Although the large majority of power-generating and industrial plants are
using these fuels, there are significant examples of other lower grade fuels
that h~ve been and are being used. These fuels may be naturally-occurring,
manufactured, or by-product fuels. These fuels are tabulated in Table B-7,
according to Fryling's systemology (Ref. B-30). In the following sections,
examples of steam generators that have been designed for these fuels are
gi ven.
a.
Anthracite
Anthracite, in contrast with the softer bituminous
coals, which contain bitumen and much volatile hydrocarbon, is a mineral
that is nearly pure carbon. Some indication of the characteristics of an.:..
thracite fuels from different locales is shown in Table B-8.
Because of the hardness of this coal, slow-speed
pulverizing equipment must be used to avoid uneconomical shutdowns and
high pulverizer maintenance-costs. Anthracitic coals, because of their
low volatility, exhibit high ignition-temperatures. Special burner and
furnace design must therefore be used with this type of fuel. To maintain
ignition, a combination of auxiliary fuel or refractory walls is used. Fuel
is usually fired downward through arches in both front or rear walls or in
both side walls. A typical example is shown in Figure B-40. Separating-
type burners, in which the bulk of the carrier air is separated, produce a
fuel-rich mixture which is blown into the combustion zone. The basic com-
bustion technique is a delayed burning with low velocity air being admitted
through the side walls. The low volumetric-heat-release results in a rela-
tively long residence time and, thus, better burnout of the carbon particles.
B-63
-------
TABLE B-5
BREAKDOWN OF CAPITAL COSTS* FOR 200 AND 400 MW BOILERS
Bituminous Coal Natural Gas or Oil
200 MW 400 MW 200 MW 400 MW
1. Ash-handling equipment 390.7 694.0
2. Boiler feed system 612.0 1, 087. 5 612.0 1, 087. 4
3. Boiler plant cranes 23.5 41. 3 23.5 41. 3
4. Boilers and equipment 3,470. 0 6,147.5 2,896.2 5,136.6
5. Breeching and accessories 491. 8 874.3 98.4 173.5
6. Coal-handling equipment 101.6 180. 3
7. Draft equipment 573. 8 1, 021. 9 573.8 1, 021. 9
8. Gas -burning 'equipment 286.9 502.7
9. Instruments and devices 273.2 486.3 273.2 486.3
10. Lightin~ systems 13. 7 24.3 13.7 24.3
11. Oil-burning equipment 429.0 751.4
12. Pulverized fuel equipment 819.7 1,459. 0
13. Stacks 527.3 937.2 10.4 17.2
14. Station piping 1,.480.9 2,636.6 1, 480.9 2, 636. 6
15. Ventilating equipment 29.2 51. 9 29.2 51. 9
16. Water purification equip- 21 5. 8 382. 5 21 5. 8 382.5
ment
17. Water-supply systems 10.4 18. 6 8.2 18.6
Grand Total 9,033,600 16,043,200 6, 951,200 12,332,200
':' Tabulated in thousands of dollars in accordance with FPC
Electric Plant Account 312.
B-64
-------
TABLE B-6
PERSONNEL REQUIREMENTS FOR A 300-MW COAL-FIRED POWER STATION
(GERMAN OPERATIONS)
[
.
A)
Supervision
Superintendent
Electrical Engineer
Technical assistant for heat balances
Shift engineer s
Chemist
Laboratory personnel
Administrator
Store keeper
Secretary
Messenger
B)
Operation'
Shift overseers
Control room operators
Turbine operators
Boiler operators
Feedwater and C. W. equipment operators
Condenser and hydrogen plant operators
Mills and deslagging. 'plant- oper,a,to.:t>s
Coal plant opera'tors .
Deashing plant operators
Water treatment plant operators
Gate keepers
C)
Maintenance and Workshops
Workshop overseer
Head electrician
Shift mechanics
Shift electricians
Turners and millers
Instrument technicians
Welders
Blacksmith
Pipe fitter
Messengers
J~nitor
GRAND TO TAL:
1
1
1
4
1
5
1
1
1
1
I7
4
4
4
4
4
4
8
8
4
4
4
52
1
1
4
8
4
4
2
1
1
2
1
2"9
98
B-65
-------
TABLE B-7
CLASSIFICA TION OF FUELS
Type of Fuel
Natural Fuels:
So lid
Coal
Anthracite
Bituminous
Sub-bituminous
Lignite
Peat
Wood
Liquid
Petroleum
Gaseous
Natural gas
Liquified petroleum
gases (LPG)
B-66
Manufactured or By-Product Fuels
Coke and coke breeze
Coal tar
Lignite tar
Charcoal
Bark, sawdust,
Petroleum coke
Bagas se
Refuse
and wood waste
Gasoline
Kero sene
Fuel oil
Gas oi 1
Shale oil
Petroleum fractions
and residues
Refinery gas
Coke ovea gas
Blast furnace gas
Producer gas
Water gas
Carburetted water gas
Coal gas
Regenerator waste gas
-------
TABLE B-8
CHARACTERISTICS OF ANTHRACITE FUELS
tP
I
'"
-...J
Units {
Source Pennsylvania Spain Wale s Belgium France Korea
Moisture % 12.5 18.3 8. 00 20.00 14. 0 8. 0 7 4.00 8.77 12.00
Volatile Matter % 4.8 5. 0 6.30 4.15 5.4 :.5. 5 9 9.'-00 5.73 4.00
Fixed Carbon % 69. 6 56. 5 60.70 50.15 53.6 63. 5 67 65.00 62.84 60.81
Ash % 13. 1 20.2 25. 00 25.70 27.0 23.0 17 22.00 22.66 35. 19
Fusion Temp. of Ash of 2650 - 2240 2315 2322 2550 2370 2237 2140 2800
Grindability - 40 40 55 45 50 55 80 60 50
I
Heating Value (HHV) Btu/lb 10, 970 8,845 - 7,750 8,400 10, 070 11,800 11, 080 9,622 8,100
-------
PENDANT
SUPERHEATER
DIVISION WALLS
SUPERHEATER
CONVECTION
SUPERHEATER
REHEAT
CONTROL DAMPERS
BURNERS
F.D. FAN
ri-
I.~--.
--,---- _.-=------
SPRAY CONTROL HEADER
~.....~.~,.~....."tr.~:..'.~ ~.",""'.'''-'-'~'''''''' ',""""',0"'",'. '\. -."- "\.~'\..-.'.. ""-""1:.:",__,-0, '''.T.,;{'C'"- ~- . . . ,
SUPERHEATER OUTLET
REHEATER OUTLET
REHEATER
REHEATER INLET
FEEDER
BALL MILL
PUL VERIZERS
//./' // ,././, ,// ,-."J' /",.
FIGURE 8-40. ANTHRACITE-FIRED STEAM GENERATOR
B-68
-------
Units have been built in the United States (Ref. B-44), United Kingdom (Ref.
B-45), Spain (Ref. B-46), Belgium (Refs. B-47 and -48), and Korea (Ref.
B-4()). The largest single unit has a capacity of 500 MW.
b.
Lignite
This material has a high moisture content and burns
with a luminous, but low-temperature, flame. Because the furnace walls
are subjected to a lower heat-flux, lignite-fired steam generators are larger
than bituminous-coal-fired boilers of the same capacity. However, the for-
mer require less relative heat absorption to obtain the same furnace outlet
temperature, which somewhat reduces the size factor between lignite- and
bituminous -coal-fired boilers. However, a greater proportion of the heat
must be transmitted through the convective sections of the lignite-fired
furnace (Ref. B-38).
Lignites, even from the same mine, exhibit wide
variations in heating value, ash fusion-temperature, and grindability .
characteristics. Lignites also have fouling tendencies, and great care
must be taken in their use in steam generators, especially with regard
to sodium content. Typical analyses are shown in Table B-9.
Lignites generally ignite readily and maintain a
stable flame. Medium-speed pulverizers can be used for grinding. Typical
units in operation in the United States are described in References B-50 and
- 51. European units typically recirculate large-amounts of flue gas from
the furnace to dry the pulverized lignite (Ref. B-52). All of these units
have dry-bottom furnaces. Slagging furnaces are also used, however.
One cyclone burner unit in operation in the United States is discussed in
Reference B-53. A unique technique of burning (Ref. B-54) is incorporated
into a lignite-fired unit of German manufacture located in Greece. In this
unit, lignite is pulverized and conveyed to the furnace with hot air. How-
ever, part of this stream is conveyed to cyclone separators above the steam
generator. The dry lignite is then fed by gravity into the furnace zone be-.
tween the other lignite burners. .
c.
Peat
Although not a conlmercial fuel in the United States,
countries such as Ireland, where there is little coal, use peat to a consider-
able extent (Ref. B-30). Large reserves of peat are also found in other
countries. Typical Analyses are shown in Table B-9. Peat has been com-
mercially fired in small steam generators either on a travelling grate or
in pulverized form (Ref. B - 52).
d.
Wood Wastes and Waste Liquor
makes
of this
Starting from timber, the pulp and paper industry
paper from the cellulose fibers, which amount to about 50 percent
primary raw material. The wood is converted into pulp by chemical
B-69
-------
TABLE B-9
CHARACTERISTICS OF LIGNITE AND PEAT
Lignite Peat
North Dakota Germany Ire land Germany
Moisture, wt-o/c 36.4 36. 5 50-60 40. 0 45.0 32.0
Volatile Matter, wt-o/c 28.7 18.4 29. 0 9. 0
Fixed Carbon, wt-o/c 28. 0 35.4 25.0 59.4
Ash, wt-o/c 6.9 6.03 10 6.2 1.0 1.6
Fusion Temp. of Ash, of 2135
Grindability 45
HHV, Btu/lb 6,750 7,000 4, 500-5, 580 5,290 4, 020 7,340
B-70
-------
methods, and steam generation becomes an integral part of the operation
wherein chemicals are recovered. Steam is generated by burning the wood
wastes and waste liquor derived from the process. Supplementary steam
and power for the conversion of pulp to paper may be obtained from power
boilers burning conventional fuels, if there is an insufficient supply from
bark boilers and chemical recovery units (Ref. B-30).
The chemical recovery unit was developed in the
1930's. By the 1950's, stearn conditions of 600 psig and 7500F were being
used. Currently, units operate at 1200 psig and 900oF. A typical stearn
generator is shown in Figure B-4l; this design features a horizontal, con-
tinuous-tube economizer, tubular gas air-heater, and cascade evaporator.
In the recovery unit, the concentrated black liquor is sprayed upon the fur-
nace walls for dehydration prior to final combustion of the dried char on the
furnace hearth. In the furnace, heat is obtained from the combustion of or-
ganic liquid constituents. (dissolved from the wood). Of equal importance,
the inorganic constituents (sodium salts) in the liquor are recovered as
molten ash or smelt. The lower part of the furnace is actually a chemical
retort. Incomplete combustion of the char in the porous bed supplies in-
candes cent carbon and carbon monoxide, which act as reducing agents to
convert the sulfate in the smelt to sulfides and sulfite. To withstand the
erosive and penetrating characteristics of the smelt, special construction
is used in the lower parts of the furnace walls and the floor to assure that
they are leakproof as in slagging furnaces (Ref. B-32).
Wood refuse available as a fuel may consist of large
pieces such as slabs, logs, and bark strips, and small pieces, such as saw-
dust and shavings. Furnaces for burning wood refuse are usually designed
to handle chip size, in which case it becomes necessary to pass the larger
pi~ces through a hogger or chipper. Reducing the wood to chip-size permits
uniform continuous feeding, a more rapid burning of the small particles,
and a more complete coverage of the grates (Ref. B-32).
Typically, wood has a heating value, on a dry basis,
of 8,000 to 9,000 Btu/lb, but the moisture level may be as high as 80%.
Mechanical means are generally used to reduce the moisture to about 60%
for burning. Typical wood-bark has a moisture content of 40% and a heating
value of 5,490 Btu/lb.
Hogged wood-refuse has successfully been burned
on a thin bed. In these units the wood is blown into the furnace above a
spreader stoker as shown in Figure B-42. In this manner, smaller par-
. ticles dry out and burn in suspension while the remainder is burned to
completion on the grate. Fly ash reinjection is often included in these
units. The bark may be burned either alone or in combination with other
fuels. When coal is the auxiliary fuel, the coal may be burned on the same
spreader stoker, or pulverizers may be used. The choice is usually dic-
tated by economics. In areas where fuel costs are high, the increased
B-7l
-------
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il-
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.
30FT
BLACK-LIQUOR RECOVERY UNIT
FIGURE B-41.
b.?2
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i
PENDANT
SUPERHEATER
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30FT
FIGURE 6-42. WQOD-WASTE-FIRED STEAM GENERATOR WITH SPREADER STOKER
B-73
-------
boiler efficiencies -that can be realized with pulverized coal will generally
offset higher first-cost. Other conditions, such as use-factor, purchased-
power costs, proportions of fuels to be burned, steam conditions, and steam-
flow variations, will also affect the choice of the coal-firing method (Ref.
B-30). One large-sized, combined-fired unit has a steam capacity of 450,000
lb/hr at 1335 psig and 9580If when burning natural gas and bark.
Another type of continuous-feed, waste-wood-fired
steam generator is shown in Figure B-43. This unit (Ref. B-55) is designed
for combined firing and features an inclined, water-cooled grate. The de-
signed capacity is 50,000 lb/hr of wood waste (60% moisture) with supple-
mental oil or gas to produce steam conditions of 600 psig and 700oF.
A steam-raising furnace using suspension-fired
pulverized coal and hogged bark as fuel is in operation at Muskegon, Michi-
gan. This furnace generates 275,000 Ib steam per hour, which is used, in
conjunction with steam from other boilers, for production of electricity for
in-plant use. Of the 20 MW power requirement for the facility, a large
production plant for high-grade printing paper stocks and container card-
boards, only 2 MW's need be purchased from the local utility. Nominal
design of the unit is 48,800 Ib/hr of bark (4500 Btu/lb) and 23,800 Ib/hr
coal, but bark availability usually limits this fuel to 12,000 to 15,000
lb/hr.
Bark is passed through a single stage hogger, with
typical particle size distribution (wt-%) of the effluent being as follows:
+ 1/4-in.
+ 1/8-in.
- 1/8-in.
- 112 in.
- I/4-in.
De s c ri ption Softwood Hardwood
Long fibrous strands 2.6% 10.4%
2-Ao 3-in. strands 2.5 5. 1
1- to 2-in. strands and 5.6 13.8
large chips
Short strands and chips 16.3 19. 1
Small curds 12.6 13.4
Fines 60.4 38.2
Screen
+ I-in.
+ 3/4-in. - I-in.
+ 1 12 - in. - 3 14 in.
This material is conveyed to a live-bottom silo
where the small quantity of sawdust from the mill is admixed. From here
it is moved to a distributor for equal division to four pneumatic blowers.
Even though Teflon coated, the distribution system tends to become fouled
with resins from the wood and unequal quantities of bark are fed to the
blowers. This is believed to be the cause of the minor buildup of burning
wood on the grate; a superior means of distribution is being sought. The
blowers transport the bark approximately 150 ft to the furnace, where it
is introduced through a 6-in. pipe tangentially between two corner coal
guns; an oil system is also available.
B-74
-------
a
AIR HEATER
I
I ,
I
I
I
I
. ..
i\
TO ASH
DISPOSAL
REFRACTORY
, HEARTH
/V .
3.CAST ~PPROXIMATE CONTOUR I',
FEED CHUTE' OF WOOD REFUSE
NIPPLES FUEL BED
WATER COOLED
INCLINED GRATE
3.GU ILLOTINE TYPE
ASH REMOVAL DOORS
SHIELD
FOR PROTECTION
OF OPERATOR
WHilE REMOVING
ASH
SEPARATELY
CONTROLLED
OVERFIRE
AIR SUPPLY
o
FIGURE 6-43. WOOD-WASTE FIRED STEAM GENERATOR WITH INCLINED
WATER-COOLED GRATE
B-75
WATER COOLED
GRATE BARS
h
CLAMPS
-------
Visual observation of the furnace indicates all but
a small fraction of the bark burns in suspension. At times, a buildup of
some 3-ft in height occurs in the corners of the 12-ft2 grate, :located some
20 ft below the pneumatic guns, at which time the pile topples and permits
combustion to be completed. Consideration is being given to addition of
small diameter air jets above the grate to minimize fuel buildup in stag-
nant areas.
Separate measurement of bottom ash and fly ash
is not made, but it is claimed that the former is only a very small per-
centage of the total. A material balance has not been attempted. Carbon
content of the over-ash has been found to run as high as 10 to 12%.
The paper company regards this unit, the only
steam generator now in operation that is tangentially fired with waste-fuel,
as a. definite success.
As with most fuels, a careful study of the ash from
coal and bark should be made, especially if both are to be fired on the same
grate. It has been shown that initial deformation, softening, and fluid tem-
peratures of proportional amounts of coal and bark ash will vary in an un-
predictable manner. Figure B-44A illustrates a fractional analysis con-
sidered acceptable for simultaneous firing. Figure B-44B illustrates an
incompatible mixture (Ref. B-56). This criterion would also apply to some
degree to combined bark/pulverized-coal firing, since slagging in the fur-
nace and convection sections is rather limited.
e.
Bagasse
This waste material has been utilized commercially
in relatively small steam generators. In some cases, bagasse is burned
in batches on hearths. In general, however, it can be stoked into furnaces
of essentially the same design as used for waste-wood firing. A design
very similar to that shown in Figure B-43, for example, has been used for
bagas se-firing. Units are also under construction which will operate on
the principle of tangential waste-fuel injection. Where copious fuel supplies
are available year around, it is possible to operate bagasse-fueled boilers
without resorting to combined-firing.
5.
A ppli ca tions fo r Refus e - Fi ring
a.
Steam Cycles
As a waste fuel, refuse does not have the desirable
properties of fossil fuels. It has a high ash and moisture content. How-
ever, its combustible portion is rather volatile.
B-76
-------
2700
2600
2500
LL 2400
o
UJ
a::
::) 2300-
~
-------
In projecting how refuse may be exploited for power
generation, utilization of its energy has been considered separately and in
combination with coal for various portions of the steam cycle, including
feedwater heating, boiling, superheating, and reheating (Refs. B-57 to
B -72)*. It was considered and rejected as the sole fuel for feedwater
heating, boiling, and superheating, wherein the steam generated would
be combined with the outputs of conventionally fired units in a common
manifold for expansion in several turbines (Refs. B-63 to B-65). The
basis of rejection was the wide variations in steam-flow rates and the
prevalent domestic practice of connecting the steam lines between the
steam generator and the turbine directly.
b.
Firing Methods
Various methods of burning refuse either alone
or in combination with coal have been practiced and proposed (Ref. B-66).
An early method was the burning of "as received" refuse with conditioning
of oversized refuse on a stoker. Travelling grates were largely rejected
due to their inherent inability to agitate the refuse. Agitating grates such
as backward or forward reciprocating grates may be considered as a generic
type on the basis of their utilization for solid fossil-fuels as well as refuse.
The roller grate was developed solely to burn refuse, although its handling
and burning characteristics and performance are similar to reciprocating
grates.
Utilization of this type of steam generator has been
largely confined to European municipalities, particularly in West Germany.
An example of a domestic unit of this type, the first constructed (1965) in
this country, is shown in Figure B-45. This unit is equipped with a recipro-
cating grate and incorporates a supplemental oil-firing capability. Unlike
the European counterparts, which are typically coupled with turbines, this
unit operates at steam conditions (275 psig and 4150F) intended for ship-
service lines on nearby Naval docks (Ref. B-59 and -67).
Spreader stokers have been considered, not only
on the basis of their utilization with solid fossil-fuels, but with such waste
fuels as hogged wood-bark (Refs. B-30, -32, and -56). This type of stoker
is presently being considered for burning refuse, which has been conditioned
to a nominal 4-in. top size (Refs. B-68 and -69). Shredding not only pro-
duces a more uniform sizing but also helps distribute (and somewhat reduce)
the moisture. It thus tends to make a heterogeneous fuel more homogeneous,
at least on a macroscopic basis.
Recent experience has indicated that size reduction
results in a significant increase in the burning rate of refuse. At Plaquemine
Parish, Louisiana, it has been reported that the use of refuse-grinding
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equipment has led to a firing rate increase of from 2100 to 6000 lb/hr.
The material is stoked onto travelling grates. This small installation is
a refractory-wall incinerator, however; whether similar benefits could
be expected from a steam- raising unit is uncertain.
A further step in this direction is the suspension
type of burning*. In this method, refuse is conditioned to a nominal 2-in.
top size, or smaller, and blown into a furnace. As the refuse falls, high
velocity air jets tend to create a high degree of turbulence. In this method,
a grate at the bottom of the furnace may be essential for complete burnout
of the refuse. Interest in this method is based on its previous utilization
for waste fuels such as wood bark (see above and Ref. B-56), which is now
also being extended to refuse (Refs. B -70 to B- 72).
Another system for suspension burning is the arch
furnace. This configuration employs no moving grate. This method has
been considered on the basis of its succes sful utilization with low-volatility,
solid fossil-fuels (e. g., anthracite; see Figure B-40). While refuse is un-
like low volatile fuels having high ignition temperatures, such as anthracite,
this method provides a considerable residence time in which to promote the
complete burnout of the fuel. In this method, air is injected along the tra-
jectory of the burning fuel particles, providing a streamline flow to the
convection sections of the steam generator. It is reasonable to expect that
the refuse-input of an arch-furnC!-ce unit will be at least twofold greater
than the maximum allowable for a grate-equipped furnace of the same size.
Slagging furnaces have been discussed earlier in
terms of their operations with solid fossil-fuels and also as chemical re-
covery units in pulping plants. This type of firing is presently being tested
for burning refuse (Refs. B-73 and -74).
In this context, the eval,uation of the basic input-
data available raises several serious technical questions. Vv'hile the proto-
type units are of small capacity, it would appear that pool capacities would
be small and not readily adaptable to the large- sized pools deemed to be
essential for large capacity steam generators. Critical properties for
slagging furnaces are viscosity and melting-temperatures, reported to be
between 26000 and 32000F. The absolute values of these properties must
be known with some degree of precision and these values should not vary
greatly. Ash-melting temperatures, however, are quite dependent on the
levels of the constituents present (Ref. B-75). The experience with chemical-
recovery units has been marked with episodes of tube corrosion; this same
potential exists for refuse-firing in slagging units (Ref. B-76 and -77). It
would appear that a firing method, shown to be unfavorable with a homo-
geneous fuel, should be an unlikely candidate for power generation when
firing a heterogeneous (variable-ash) fuel.
':'See Section III, B, 4 of Volume 1.
B-80
-------
C.,
Power Output Fluctuations
, Power output from a system using refuse as a fuel
will fluctuate due to the highly heterogeneous nature of refuse. Several
different methods are used in Germany to prevent the power-output from
fluctuating to an extent that it cannot be handled by the system. These
methods are:
5
Selective loading of refuse bunkers to
obtain a good mixture of the available
types and qualities of refuse.
.
Constant mixing in the bunkers, usually
by means of the charging cranes, to in-
crease the uniformity of the mixture.
.
Oil-firing to support the incineration'
of refuse.
Oil firing is not required to stabilize the power out-
put in all cases. The neighboring power stations and system distribution
networks often compensate for fluctuations that occur. The control concept
that one German manufacturer (Ref. B-78) recommends for refuse-burning
power plants is to equip the turbines with initial-stage pressure regulators.
IV.
AIR POLLUTION CONTROL
A.
NA TURE OF EMISSIONS
1.
Gross Products of Combustion
Because 10 to 12 lbs of gaseous products are typically
formed per lb of fuel burned, the combustion of fossil fuels for power gene-
ration requires the handling of enormous quantities of gas. Although a pre-
cise determination of reaction products is normally made by a molecular
balance based on the ultimate fuel analysis, reliable approximations can
be derived from the as-fired heating value of the fossil fuel and the observed
values of theoretical air required to combust a specific equivalent o~ Btu's
available in that fuel. The weight of theoretical air required per 10 Btu
has been tabulated (Ref. B-32) for fuel oil (7.46 lb), natural gas (7.20) and
coal. In the last case, the value can be taken from a graph on which theore-
tical air is plotted against the percent of volatile matter in the coal (dry,
ash-free basis). As a rough approximation, the weight (lbs) of theoretical
air required per lb of fossil fuel is equal to the as - received heating value
{Btu/lb} of the fuel divided by 1300.
B-8l
-------
As will be shown, the total gas-volume is a critical para-
meter in the selection and design of air pollution control equipment. A
statistical average of design gas-flows for power-generating boilers, based
on net megawatt output, is shown in Figure B-46.
2.
Particulate Emissions
Approximately 800/0 of the potential ash in pulverized coal
is released and entrained as fly ash in the suspension-burning process. This
is reduced to a probable value of less than 200/0 for the special case of grate-
burning of coal, although the amount of ash transported in the flue gas is
strongly influenced by the grate air-velocity. Not all of the fly ash entrained
in the flue gases can be identified as normal components of the fuel ash.
S()me of the particulates are unburned fuel and acidic smuts, containing re-
action products of the interior furnace/boiler surfaces. Generally speaking,
however, the chemical properties of the particulates are determined by the
specific composition of the fuel. A typical analysis of fly ash from a coal-
fired unit might include: 200/0 Fe203' 15% (or less) A1203' and 30% Si02.
The remainder would consist largely of CaO, MgO, Ti02' and various
sulfates. Of the sulfur introduced into the coal and/or oil combustion*
reactions, less than 50/0 becomes deposited as sulfur compounds in the fly
ash.
a.
Particulate Levels
Reliable statistical correlations between particulate
concentrations and the ash content of coal have been reported (Ref. B-79)
for suspen:;;ion-fired (pulverized coal) and cyclone (crushed coal) furnaces.
These are shown in Figures B-47 and -48. Even finer (unpublished) corre-
lations have been4made between the particulate concentration and the ash
equivalent per 10 Btu. Ash/particulate concentrations for stoker-fired
units have not been well correlated, due to gaps in reinjection data and
underfire-air relationships.
Similarly, particulate concentrations for oil-fired
units have not been well-defined. Due to the low ash-content of oils, the
particulate problem associated with large oil-fired units is usually caused
by acidic smuts. These arise due to localized (S03 - condensation caused)
corrosion that results in the formation of metallic sulfates. These sulfates
become adsorbed on carbonaceous fly ash particles; the resulting smut and
soot fall- out thus constitutes the nuisance identified with oil-firing. The
actual ash and unburned matter, being extremely fine, also causes a plume-
opacity problem. Overall particulate concentrations from large oil-fired
units are very low, being on the order of O. 1 to O. 2 grains /SCF (Ref. B - 80
and -81). Small, through intermediate-sized, oil-fired boilers, with their
>:
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2.0
1.6
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o
o
200
400
600
800
1000
1200
UNIT SIZE, MW
FIGURE 8-46. GAS FLOW VS GENERATOR OUTPUT
B-83
-------
10
c
LL. "
0 ,.,.,
U) ",
'- .",
~ ".,.
t!) 8 ".,. 0
,. ".,.
(.) 0 /' 9~~
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AS H IN CO A L. %
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FIGURE 8-47. DUST CONCENTRA' : I : SUSPENSION-FIRED FURNACE
-------
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ASH I N COAL. %
15
20
FIGURE 8-48. DUST CONCENTRATION: CYCLONE FURNACE.
-------
inherently lower combustion- efficiencies, produce effluents with slightly
higher particulate concentrations. In all unit sizes, the introduction of
magnesium-based additives about doubles particulate output. These ad-
ditives are commonly used to reduce superheater corrosion and air heater
pluggage. There is recent evidence (Ref. B-82) that such additives enhance
overall system performance of the electrostatic precipitation proces s.
b.
Physical Properties
(1 )
Particle Size Distribution
Data on particle size distributions have been
published (Ref. B-79) for suspension-, cyclone-, and stoker-fired boilers,
as shown in Figures B -49 through B -51 , respectively.
Due to the physical instability and the hygro-
scopic nature of oil-derived fly ash, reproducible determinations of particle
size distributions are difficult to achieve. Data have been reported (Ref.
B-83) which indicate that a relatively coarse particle (60% >10/-,) is found in
the flue gas of oil-fired boilers. Tar camera data, photomicrographed
glas s -impaction- slides, and field tests on mechanical collectors (Refs.
B-80 and -81) indicate that a much finer material exists (90% < I/-,) in situ.
Table B-IO furnishes a summary of particulate
concentrations and size distributions for various fossil fuel combustion
systems.
(2 )
Density and Specific Gravity
Apparent, or bulk, densities of fly ash, which
are only employed in sizing hoppers, bunkers, or silos, can range from 20
to 120 Ib/ft3. Actual or true specific gravities are required, together with
particle size data, for selecting inertial particle collectors. For coal fly
ash, true specific gravities range from 1. 2 to 3.2. Reliable values for
oil-derived ash have not been reported, presumably because of the instability
problem mentioned earlier. Freshly collected oil-ash is very light and
fluffy, suggesting a low bulk-density.
(3 )
Bulk Resistivity
Bulk Resistivity of fly ash is an important de-
sign parameter in the consideration of electrostatic precipitators. Absolute
values have been published (Ref. B-84) and the Government is sponsoring
several programs (Refs. B-85 and -86) in which the in situ determination
of resistivities of fly ash from coal-fired boilers is being determined.
-"
B-86
-------
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TABLE B-lO
SUMMARY OF PARTICLE EMISSION DATA
Boiler Emis sions Particle Size Distribution
Grains/SCFDI % of Coal Ash %<10 microns
Type of Firing Avg. Max. Avg. Max. Average Finest
Pulverized Coal 2. 9 3. 9 80 120 44 58
Cyclone 1.0 1.7 28 47 65 72
Stoke r 23 30
Reinjection:
None 1.0 28 NA(2) NA
100% 4.0 110 NA NA
Partial 1. 0 28 NA NA
Oil-Fired
Inte rmediate O. 1 0.2 90 (3) .. --
(>150MW)
Small « 1 00 MW) 0.15 O. 3 90
1 )
2)
Based on average of 10% ash in coal
NA = Not Available
3)
Probable in situ
B-90
-------
Relative resistivity y.!. temperature data for
fly ash of suspension-fired coal of varying sulfur content have also been
reported (Ref. B-87). Figure B-52 illustrates this relationship. The de-
crease in fly-ash resistivity with increasing coal sulfur-content is attri-
buted to the concomitant variation in S03 levels. A portion of the reaction
products of S03 are absorbed on the fly ash and cause the surface conduc-
tivity to increase. Thus, as the.,suliur content of the coal and the S03
level in the flue gas increase, the resistivity of the fly ash will decrease.
This also explains why, in applying flue-gas desulfurization processes in
which fly ash is not removed (e. g., dry limestone or dolomite injection),
the efficiency of an electrostatic precipitator will be reduced.
. The combustible carbon-content of the fly
ash, which is largely determined by the screening or sizing of the fired
coal and the combustion efficiency of the furnace, also influences re-
sistivity. The chemical composition, notably the alumina and magnesia
content, also plays an important role. The following table illustrates
this for two ashes from coals having identical proximate analyses:
RELATIVE FLY ASH ANALYSES
Proximate Ultimate Ultimate
Analysis Analysis Analysis
Coals A & B Ash A Ash B
As Fired Dry Basis % %
Moisture, % 14.Z 0 Fe203 14.2 6.4
Vol. Matter, % 35.2 41. 0 Al203 20.0 32.6
Fixed Carbon, % 45.8 53.4 SiOZ 28.2 38.7
Ash, % 4.8 5.6 CaO 23.8 9.86
Sulfur, % 0.45 0.53 MgO 5.04 1. 43
S03 2.83 0.88
Bulk Resistivity @ 300oF, Ohm- cm 3 x 1011 2 x 1013
Finally, moisture is an agent that will greatly
increase surface conductivity. This is demonstrated in Figure B-53, which
was published by White (Ref. B-84).
3.
Gaseous Emissions
On an average basis, the gaseous products of fossil-fuel
combustion will include approximately 6% moisture for coal and oil (slightly
higher for gas), 12% C02, 6% 02, and the balance N2' This is based on 20%
exces s -air operation. The principal gaseous pollutants include:
B-91
-------
-
w
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0:=
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C
IX:
o
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W
IX:
0.5°k5
250
300
350
400
4",,0
TEMPERATURE, ° F
FIGURE 8-52. RELATIONSHIP OF FLY ASH RESISTIVITY TO
COALSULFUR~ONTENT
B-92
-------
1015
1014
E
"
I
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r.
o
.; 1013
~
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1012
lOll
o
100
400
200
300
500
600
FIGURE 8-53. EFFECT OF FLY ASH MOISTURE CONTENT ON RESISTIVITY
B-93
-------
VI
Sulfur Oxide s (S02' 503)
Nitrogen Oxides (NO)
x
.
.
Carbon Monoxide (CO)
.
Hydrocarbons
Average values for these compounds in stack gases of coal-fired power plants
have been reported (Refs. B-88 and -89) and are tabulated in Table B-ll.
a.
Sulfur Oxide s
The oxidation to sulfur dioxide of sulfur-containing
compounds in fossil fuels readily goes to completion. Further oxidation to
503 occurs to a small extent. As shown in the following table (Ref. B-81),
the fossil fuel combustion-process appears to tie up 85% to 95% of the available
fuel-sulfur as 502; 1% to 3% as S03; and less than 5% in the ash.
GASEOUS EMISSIONS FROM LARGE UNITS
NO 5°2 5°3
x
-lppm) (%)* (%)* (ppm)
Extreme Range 0 - 1,020 12 - 100 0.3 - 11. 5 0 - 76
Normal Range 300 - 700 85 - 100 O. 3 - 2.8 6 - 24
Most Common Values 460 - 480 98 - 100 1.0- 1.3 14 - 22
~:
-------
,TABLE B-ll
SUMMARY OF GASEOUS POLLUTANTS (PPM, DRY BASIS)
FROM COAL-FIRED POWER PLANTS
Oxides o~ Sulfur Sulfur S03./S02 Carbon Hydro - 2 Formal-
Plant Nitrogen Dioxide Trioxide Mo'noxide Carbons dehyde
a b a b a b a b a b a b a b
1 232 664 2420 1370 4 2 0.0017 0.0015 0 0 25 7 0.30 0.25
2 406 335 1330 1820 1 19 0.00080.0104 6 '4 14 6 0.16 O. 061
3 398 520 2080 2350 25 16 O. 0120 O. 0057 7 10 16 2 0.077 o. 056
4 520 334 1850 1320 4 3 O. 0022 O. 0023 7 8 12 8 0.045 O. 054
5 593 521 830 1110 5 22 O. 0060 O. 0198 17 5 6 8 O. 11 0.066
td
I
...0 Avg 430 475 1702 1594 8 12 O. 0045 o. 0079 7 5 15 6. O. 138 O. 097
'U1
1 )
2)
Measured as NOZ
Expresaed as CH4
a :;:
Fly-ash collector input gas
b :;:
Fly-ash collector output gas
-------
b.
Nitrogen Oxides
Within this group are included four common forms:
NO, NOZ, NZ04' and NZ05. The last two are unimportant in the present
context; NZ04 dissociates readily into NOZ at the temperature of interest,
and NZ05 is thermally unstable. In the dynamics of the fossil fuel combus-
tion process, little oxygen is available for the initial formation of NO. If
the available oxygen is increased by increasing excess air, NO formation
is promoted, unles s combustion temperatures are reduced. Higher tem-
peratures result in increasingly higher NO equilibrium concentrations.
Further oxidation of NO to NOZ is favored at tem-
peratures below 4500F (Ref. B-90). The reaction is so slow, however, that
practical furnace configurations do not allow sufficient residence time for
this reaction to occur. Thus, NOx stack discharge compositions are com-
prised largely of NO (Ref. B-91).
Figures B-54 and -55 show data summarized in
References B-9Z and B-90, respectively, on NOx emissions from fossil
fuel fired sources of various sizes.
c.
Hydrocarbons
Hydrocarbon emissions are comprised of many
organic compounds: lower molecular weight aliphatics, unsaturates,
aromatics, and oxygenated and halogenated compounds. The species
which are m.ost difficult to oxidize, such as the aromatics, comprise a
substantial fraction of the overall hydrocarbon emissions. Polynuclear
hydrocarbons, notably benzpyrenes, have received considerable attention
due to their carcinogenic properties. The low oxidation propensity of
benzpyrene and other aromatics results in the formation of soot during
combustion, despite high exces s air levels.
Unburned hydrocarbon emis sions are the inevitable
result of inefficient combustion. True hydrocarbons are released during
intermediate stages of non-ideal combustion. Oxygenated or otherwise
transformed species, such as formaldehyde, are formed following this
initial cracking. True and transformed hydrocarbon emission values
have been published (Refs. B-81, -88, and -9Z) as previously shown in
Table B -11. Values of benzpyrene emis sions have been reported (Ref.
B-93) as a fraction of particulates from oil firing.
d.
Carbon Monoxide
This compound is a fuel itself, having an approxi-
mate heating value of 4500 Btu/lb. Low excess air levels or poor com-
bustion-air distribution result in a deficiency of oxygen for the complete
combustion of carbon. The CO formed can thus escape from the system
B-96
-------
...
:I:
........... 102
~
..J
,.
...
. ~
-
-
10
v
Cf)
en
::;: 1.0
w
~
z
~
-
Z
~
(!)
>
104
103
NOx=N02+ NO (CALC'D ASNOi
0.1
0.01
105
I 06 I 07 I 08
HEAT INPUT. Btu/Hr
109
1010
FIGURE B-54. ESTIMATION OF AVERAGE UNIT NOX EMISSIONS FROM SIMILAR
PIECES OF COMBUSTION EGUIP!VIENT
B-97
-------
to
I
-..0
00
105
a:
:r.:
-
In
..I
W
~
«
a:
z
52
(I)
(I)
:iE
w
X
o
z
~
z
;:)
w
~
«
a:
w
>
«
104
103
102
107
GAS-FIRED BOILERS
1000 MW / .
/ / OIL AND COIL FIRED BOILERS
750 MW i.f8 1000 MW
500 MW" 750 MW
~. 500 MW
/~
250 MW. /
// /
. 250 MW
/
/
/
120 MW
109
1010
1011
HEATINPUT,BTU/HR
FIG
: ~-55. ESTIMATION OF AVERA :1E UN!' . NOX EMISSIONS FROM LARGER SIZED COMBUSTION SYSTEMS
-------
without undergoing the (normal) further conversion to C02. Values of CO
emissions have been reported (Refs. B-88 and -89) for a variety of sizes
of fos sil-fuel combustion sources and are included in Table B-1l above.
e.
Gaseous Emissions Summary
Natural gas combustion does involve an NOx emis-
sion problem. However, no particulates or SOx, and only negligible hydro-
carbons, are associated with this type of firing. Fuel oil combustion also
produces NOx emissions, but with only traces of particulates being formed.
Sulfur-bearing oils release over 90% of their sulfur as noxious S02; only
small amounts of S03 are generated. The S03 levels will increase appre-
ciably when firing vanadium bearing oils, such as Venezuelan, in which the
vanadium acts as a catalyst during combustion. Higher S03 concentrations
result in smut formation, as well as plume opacity. Coal combustion also
results in the generation of NOx' as well as S02, and traces of S03. The
last is normally in low enough concentration to preclude smut formations.
The predominant pollutant from coal combustion is particulates.
B.
EMISSION CONTROL TECHNIQUES
1.'
Particulate-Emis sion Control Devices
There are four basic, or generic, types of particulate
collection devices:
.
Mechanical Collectors
.
Wet Scrubbers
.
Fabric Filters
.
Electrostatic Precipitators
a.
Mechanical Collectors
These devices exploit centrifugal forces to separate
particulates from gas streams. The gas is either vaned, or introduced tan-
gentially, into a tubular element. The resulting tangential velocity causes
the particulates to centrifuge from the gas stream. On large units, tubular
elements are often arranged in multiples of several hundred tubes (multi-
cyclones). One such tube element is shown in Figure B-56.
Being es sentially inertial in character, mechanical
collectors are selective with respect to particle size and density. Multi-
cyclones are often used to fractionate and reinject coarser, higher carbon-
content ash.
B-99
-------
FIGURE B-56. MUL TI-CYCLONE TUBE ELEMENT
B-100
-------
:.,.; ".."/J»
',' .
'.' ..\.
. ,.'.
Decreasing tube diameters or increasing the par-
ticulate size and density results in greater collection efficiency. Because
of practical considerations, such as ash-pluggage and ease of fabrication,
9 or 10 in. (I. D.) tube is shown in Figure B-57. As is' evident, moderate
pressure drops of 2 to 3 in. W. C. are not uncommon.
With a 2 to 3 in. W. C. pressure drop, a mechanical
collector can be expected to exhibit 75 to 80% collection efficiencies on sus-
pension-fired (pulverized coal) units. The relatively low performance and
relatively high power input of mechanical collectors are their principal dis-
advantages. Their main advantage is their low installed cost, which is on
the order of $0. 15 to $0.25 per ACFM of gas.
b.
Wet Scrubbers
These devices cause droplets of scrubber liquid to
impinge with the particulates entrained in the flue gas. The size and weight
of the particulate is effectively increased by wetting, so that they can then
be collected by mechanical (inertial) separation. Scrubber performance
depends on collisions between scrubber liquid droplets and particulates;
these collisions can be increased in three ways:
.
Increasing turbulence
.
Decreasing liquor droplet-size
by atomization
.
Increasing amount of scrubber
liquid us ed
Semrav (Ref. B-94) summarized the pow;er inputs
required to accomplish the first two effects. He concluded that scrubber
performance is basically a function of power input.
The effects of relative liquor concentration (liquid
to gas ratio), although not widely reported, are well known by equipment
suppliers. So- called Stefan Flow Effects are largely undefined for situations
where condensation or evaporation processes occur.
Daily swings in generator output and boiler operation
are common in all but the largest base-loaded units. As a result, variations
in gas volumes must be handled. Variable orifice contactors similar to that
shown in Figure B-58 are well suited to this type of operation, provided plug-
ging does not occur.
B-lOl
-------
100
90
80
70
~ 60
0
..
>- 50
u
z
w 40
-
u
tJj ~
I I.L 30
..... I.L
0
N LaJ
20
10
0
0 5
..-j.Y" --~.. ..':
.;..,~ .~. -... .. .'~ .-
lnches. WC
0.5
1.0
2.0
3.0
DUST CONC"; 3.0 Gr/Cf'
GAS TEMPERATURE"'70@=70()@f'
SPECIFIC GRAVITY- 2.0
10 15 20 25
BAHCO PARTICLE DIAMETER. MICRONS
30
: GURE 8-57. ~YCLONE DUST COLLECTOR - EXPECTED MICRON EFFICIENCY
-------
FIGURE B-58. VARIABLE-ORIFICE LIQUID SCRUBBER
B-103
-------
Although capable of much better collection efficiency,
scrubbers require higher power-inputs than mechanical collectors. Wet
scrubber installed-costs for power boilers are sharply increased by the
required stainless-steel construction; installed costs of $0. 50 to $0.60 per
ACFM are common. Additional process details, such as consideration of
water-availability and wet-ash and effluent-water disposition, must also be
made. Although the wet scrubber requires about the same physical space as
a mechanical collector, the associated water- and ash-handling equipment
can impose an additional space demand of 2 or 3 times that space.
In terms of SOx and particulate removal, wet scrub-
bers have shown 99% overall collection-efficiencies at 6-in. W. C. pres sure
drop on suspension-fired boilers using the dolomite-injection proces s (Ref.
B-95).
c.
Fabric Filters
Similar to the operation of a household vacuum
cleaner, dust-laden gas is passed through a filter cake of collected ash
deposited on the fabric envelope. Fabric filters are capable of 99+% col-
lection efficiencies. While simplicity and good performance make these
systems attractive, space requirements and pres sure drop, typically 5 -in.
W. C., are serious disadvantages. Periodic filter media replacement is
also required, which adds significantly to operating costs. A multitubular
bag house is shown in Figure B-59.
Installed costs for fabric filters are typically $1. 00
to $1. 25 per ACFM, and space requirements are two to three times that for
inertial collectors.
d.
Electrostatic Precipitators
These devices employ high intensity electrical fields
to separate particulates electrostatically from the flue gas. Although rela-
tively insensitive to particle size variations, precipitators depend on particle
resistivities that are consistent with effective 0f;eration. White (Ref. B-84)
has indicated that fly ash resistivities below 10 2 ohm-cm are considered
good for electrostatic precipitation. This is shown in Figure B-60.
Single- stage electrostatic precipitators, as shown
in Figure B-61, will remove up to 99.5% of entrained fly ash. Space re-
quirements are similar to those for fabric filter, as are installed costs.
Operating costs, however, are significantly lower, owing to the fact that
less than O. 5-in. W. C. pressure drop is typical. Precipitator size and
installed cost are sharply influenced by the bulk resistivity of the fly ash.
The precipitation rate or migration velocity (w), shown in Figure B-60, is
an overall performance factor which is observed in establishing the required
collecting plate area, and thus the overall size and cost of the precipitator.
The relationship is given in the Deutsch (Ref. B-96) equation:
B-I04
-------
tP
,
......
o
U1
"
J':;
..
(
.:/
FIGURE B-59. MULTI-ELEMENT BAG HOUSE
-------
0.6
,
"
,
,
0.5 '
u
G»
fJ)
,
- 0.4
IJ...
,.
-
~
-
W
I-
-------
" ~\
<-
~~~
\.~\
\ "\.\
-t.
t~~
--
---
\~
~~\
FIGURE 8-61. SINGLE-STAGE ELECTROSTATIC PRECIPITATOR
B-I07
-------
Aw
N::: l-e-V
where:
N ::: collection efficiency
A ::: collecting plate area (ft2)
W ::: precipitation rate (ft/sec)
3
V ::: gas-flow rate (it /sec)
Electrostatic precipitator installed costs are given
in Figure B-62 for several typical operating conditions.
2.
Gaseous-Emissions Control Devices
a.
Sulfur Oxides Control
Three basic modes of control of this pollutant- das s
are possible:
.
Fuel desu~furization
.
Flue-gas desulfurization
.
Dispersion
Obviously, the last is not a true control technique, for it is only effective in
reducing local ground-level concentrations. Although the upper atmosphere
has the fortunate capability of transforming or dissociating many compounds,
this capability must be regarded as finite. Consequently, dispersion is nor-
mally considered as only a stop-gap control technique.
The U. S. Bureau of Mines has been very active in
studying both fuel and flue-gas desulfurization systems. To date, however,
fuel desulfurization is still very expensive. A typical economic penalty for
producing low-sulfur fuel (Ref. B-97) is $0.10/106 Btu.
The state of the art in flue-gas desulfurization has
advanced rapidly over the past decade, primarily due to a thrust of activity
by the EPA and the Bureau of Mines.
While dozens of processes are being considered and
are perhaps technically feasible, only four are now at second generation, or
commercial stages, of development (Refs. B-98 and -99). These are:
B-I08
-------
106
*
-
t-
CI)
,...
:E
w
t-
CI)
,
CI)
105
D
FUEL
I. VENEZUELAN OIL
2. PULVERIZED COAL(3%'S)
3. CRUSHED COAL (3% S)
COLLECTION
EF FI CI ENCY~%
90
99
98.5
106
107
GAS VOLUME,ACFM
FIGURE 8-62. ELECTROSTATIC PR.ECIPITATOR INSTALLED COSTS,
VS-GAS THROU'GHPUT" .
B-I09
-------
iiI
Reinluft (Reinluft/Gmbh)
.
Catalytic Oxidation (Monsanto)
.
Alkalized Alumina (BuMines)
.
Reactive-Stone Injection
(EPA/Comb. Engrg.)
Figures B-63 through -66 diagram these processes.
The first three involve somewhat complex chemical-process hardware, while
the reactive-stone (dolomite) injection process is more straightforward. Per-
haps because of this, the dolomite injection proces s has been advanced to the
point closest to practical application (Refs. B-86, -98, and -99). Although
commercial versioIfs of the dolomite injection process are based on wet-
s crubbing systems following the air -preheater, the EPA is investigating the
use of dry-dust collection (Ref. B -86). In tests on a dry fabric-filter, Sou-
thern California Edison Co. and Air Preheater Co. have reported that fur-
ther SOx reductions are realized by pas sing the flue gases through the bag
filter-cake.
As mentioned earlier, reduction of the flue- gas sul-
fur oxide levels will have a detrimental effect on electrostatic precipitator
performance. This is an important consideration in pursuing dry flue- gas
desulfurization processes. R&D activities for optimizing the precipitation
process, as applied to dolomite-injected power boilers, is now under way
with EPA sponsorship (Ref. B -95).
b.
Nitrogen Oxides Control
As discussed earlier, NOx formation is favored by
high available excess air and high flame-temperatures. As such, present
attempts to limit NOx emis sions from power boilers have been centered on
burner and combustor design and control thereof. Until very recently, there
had been relatively little activity aimed at eliminating NOx from flue gases
by sorption or conversion. . NOx elimination has largely been sought in terms
of prevention rather than removal, although data have been reported (Ref.
B-lOO) correlating NOx emission with gas recirculation processes and the
overall aspects of the problem (Ref. B-90).
As with CO and the hydrocarbons, the problem of
NOx emis sions from large steam generators is not considered to be as
acute as is the SOx problem. The general consensus of air pollution control
technologists appears to be that NOx control will be more actively pursued
after the development of viable solutions for the SOx problem.
B-110
-------
.
---.---"
FLUE GAS
( 3004) F, SolidscO.9 ~ y/U3)
r-----J"
I
I
I
I
I
I
I
I
I
I
I
I
I
I
: -CHAR RECYCLE
I 300°F
I
I
I
I
I
I
I
I
I
I
I RECY.ClE ELUTION I
I STREAM - 6.2 °/0 OF J
I TOTAL FLUE
I GAS FLOW.
ABSORBER
-290°F
-----
COOLER
-220°F
215°F
I
I
I ;
Ilia TO REHEATER FOR
250°F STACK GAS
I
I
'11 I
700° IF
TER REGENERATOR I
I
700°F I
- J
/ - I
B
..... 15°/0 S02 STREAM TO
ACID PLANT- 0.8°/0
OF TOTAL FLUE GAS
FLOW
I
I
J
I
J.
I
I
I
I I
I I
J CHAR J
I MAKE-UP I
: :-------
I I ~
II I I FLUE GAS(CharTransport)
"-_.J : 1.25°/0 OFTOTAL FLUE GAS
- - - J .--- - _J FLOW
VIBRATING
SCREENS
I
r -_.J
,
CHAR LOSS
(Fines)
I,
I
I
I
I
I
I
I
I
L- - - - -
FIGURE 8-63. FLOW DIAGRAM - REINLUFT PROCESS
B- J 11
-------
FLUE GAS
PRE-CLEANER
--------
PREHEATED AIR
TO BOI LER
COMBUSTION
AIR
,
u
r-----..i
I
I
I
I
I
I
I H2S~ (L)
I
I
I
t
I
I
I
1
I
L_---
°
flUE GAS gOOF
-ELECTROSTATIC PPTR
>99°/0 SOLI DS REMOVAL
- 850° F
CATALYTI C - 6- 9 In. V2,05 (Gran) BED
CONVERTER i-2Ft/See LIN GAS VEL
- 8500F-230ppm S02
H2S 04
CONDENSER
AIR- PREHEATER
-LJUNGSTROM DESIGN
. COMBINES PREHEATER
AND ECONOMIZER FUNC-
TION
- 220°F
~MO-NTSANTO (BRINK)
DESIGN. FIBER BED
UNIT
H 2S 04
M~ST
ELiMINATOR
215 ° F
TO REHEATER FOR
250° F STACK GAS
~
~ H2S04 l L}
H2S 04
STORAGE
FIGURE 8-64. FLOW DIAGRAM -CATALYTIC OXIDATION PROCESS
B-1l2
-------
r-----'
I
I
I
I
I ABSORBENT
I RECYCLE
:~
I
I 6250F
I ,. - -
I I
I I
I I '
I I
I :
: :~-- CYCLONE
I I SEPARATOR
I
i V
: I HEATER I AIR
I PREHEATER
I
I I
I I
: -------L I~~OO F
I SPENT
~ ABSORBENT
. : ABSORB.
I MAKE-UP
I
I '
~---_V_---
I FLUE GAS
W (625"F. Solids
-------
!-
[j)OlO~ rU' IE ~O@
PUlVE~UZiER
1.1 TO 1.2 x
, J FOR FUE
,
FURNACE
....... BOI LER
- ECONOMiZER
-PREHEATED
AIR 6000F
"
OMBUSTION PREHEATER
AIR ..
2700F
,
SCRUBBED 2500F
- FLUE GAS ..
-
REHEATER
1600F
,.
120°F SCRUBBER
"
C
WASTE
~@<200 MIES~
STOICHIOMETR IC
L SULFU R
FLUE GAS
TO STACK
FIGURE 6-66. FLOW DIAGRAM - DOLOMITE/LIMESTONE INJECTION
B-1l4
-------
, ". .. . ~
3.
Forecast of Air Quality Standards
The evolution over the next thirty year s of air pollution
control capability will depend greatly upon ,the extent which technological
momentum maintains pace with requirements. The nature and timing of
future air pollution control legislation will very much depend upon the im-
plementation of present-generation legislation. If the technology required
to fulfill the presently evolving air quality standards is successfully de-
veloped over the next decade, new legislation should then be expected. If
implemen~tion is not technically feasible, legislators must mark time
until the technology does catch up with existing legislation. Based on the
complexity of the problem and the broadness of its scope, it appears that
the neces sary technological advances will take place only if 'very large
federal funds are expended.
Using a modified Delphi approach (Ref. B-10l) to inter-
viewing and then proceeding to: (1) the postulation of possible situations;
(2) the development of a preliminary relevance tree; and (3) estimating what
the extrapolation of past and present pollution emission levels will produce,
forecasts of air quality standards for the year 2000 were projected. Based
on this approach, it has been concluded that the most probable situation is
one wherein, initially, the air quality criteria recommended in Government
documents (Refs. B-l02 and -103) will be adopted in the six large metro-
politan areas under study (see Section II, A of Volume I). For S02, this will
require a concentration range of O. 02 to 0.03 ppm annual-mean, and a 24
hour average maximum allowable level below O. 11 ppm. For suspended par-
ticulates a maximum concentration in the range of 60 to 80 fLg/m3 annual- .
mean level will be observed. It is foreseen that these standards will be
adopted over the next year or two but that implementation to achieve the
sought-for air quality will require more than a decade.
About the year 1985, it is anticipated that a second gene-
ration of air quality standards will evolve. For suspended particulates, a
level of around 30 fLg/m3 maximum annual-mean will be called for and some
specific components may be pinpointed for essentially complete removal.
For S02 it is anticipated that the hourly and daily levels will be made much
more stringent while the annual level will receive less attention. Standards
will call for 24 hour average S02-levels to be below 0.03 ppm and annual
averages below 0.01 ppm. It will probably not be until around the year
2000 that the levels called for by the "1985 Standards" will be achieved.
About the year 2000, the evolution of another package of
air quality standards can be anticipated, but S02 and ,particulates, as such,
will not be under major attack at that time. This will be due to the nature'
of other pollutant priorities that can be foreseen, as well as to the increasing
sophistication of ambient monitoring techniques with which to detect source-
offenders.
B-1l5
-------
A number of assumptions were employed in arriving at the
preceding forecast. One of course is that needed true breakthroughs in the
control technology will be made and on time. This assumption also involves
a forecast of greatly increased Federal funding for industrial air pollution con-
trol research. In arriving at these conclusions regarding air quality standards
in the year 2000, it was not anticipated that the character of the six cities
would undergo any major revolutions except in the area of mass transpor-
tation. It was also assumed that no economic depressions or major wars
would occur during the period from 1970 to 2000.
v.
EXPERIENCE WITH REFUSE-FIRED STEAM GENERATORS -
SELECTED GERMAN PLANTS
A.
INTRODUCTION
There are few refuse- or combination-fired steam generators
in this country and none, at this writing, which are used in turbo-electric
service. For this reason, the present review topic must necessarily be
treated by focusing on European or, more specifically, German experience
with refuse-fired power plants. To base an assessment of European ex-
perience solely on a review of German practice is acceptable, because the
latter does epitomize rather well the overall European art. The plants
selected assure consideration of the best examples of grate and boiler
design, provide examples of different auxiliary-fuel use, and furnish an
opportunity to assess SOx-ash interactions. The plants that have been
analyzed in detail include:
.
The Munich North Plant, Block I and Block II
.
II
The Dusseldorf plant, one of the four identical
units
.
Two Stuttgart units
In accordance with standard German practice, the formal con-
tract acceptance tests for each of these plants were performed by the Tech-
nis cher tTherwachungs - Verein (TtJV). The TtJV is a state-sanctioned agency
that reviews and approves final design, and performs acceptance tests on
virtually all publicly-owned capital facilities. Transcripts of TtJV accep-
tance tes t data (Refs. B-1 04 to -107) on the above plants were procured
and reviewed.
B.
DESCRIPTION OF GERMAN PLANTS
1.
Munich North, Block I
This plant (see Figure B-67)>''< consists of two identical
Benson-type units, both of which are included in this review. These are
>:
-------
A
a
b:J
I
.-
.-
-oJ
SEC, 'C-C'
I~~
'..
SEC, 'A-A'
SEc.'a-B'
FIGURE 8-67. MUNICH NORTH COMBINED.FIRED STEAM GENERATOR . Bl~K I
-------
the oldest of the units under consideration and are characterized by twin-
chamber furnaces; i. e., the refuse and coal-furnace-chambers are separate
but share a common tube-wall. The combustion gases are combined at the
top of the furnace chambers, and pass through a common superheater and
economizer. All of these elements comprise one furnace setting or unit.
Each unit includes a Martin (backward reciprocating) grate for municipal
refuse combustion and a suspension-fired furnace chamber for the com-
bustion of pulverized-coal. Steam conditions for each Block I unit are
220,000 lb/hr of 2600 psig steam at l004/l004oF, while firing 660 tpd
refuse plus auxiliary coal. Maximum continuous load is 220,500 lb/hr
of superheated steam at 2,650 psig and 1004oF. The reheat steam flow
at this load is 198,000 Ib/hr at a pressure of 1,180 psig and l004oF.
Ferrous metals are removed from the combustion water-quenched residue
by magnetic equipment.
2.
Munich North, Block II
This unit, shown in Figure B-68, is the latest design
(1966) under consideration. It was evolved from the Block I units, but
with one important design change. The Block II unit is a single-chamber
furnace, with pulverized.;coal combustion occurring directly above the
refuse grate. Steam quality is identical to that of the Block I units; steam
production, at 800, 000 Ib/hr, is considerably higher.
All the electrostatic precipitators of the Munich North
plants are of Lurgi (Frankfurt) design and are horizontal-flow, steel shell
precipitators having pyramidal hoppers.
The characteristic differences between the Munich North
plants can be seen from the following summarization:
COMPARATIVE INFORMATION ON MUNICH NORTH PLANTS
No. of Turbines
No. of Steam Generators
Block 1 Block II
1 1
2 1
40 20
660 1060
Refuse Heat Input, % (LHV)
Refuse Rate, tpd
3.
DUsseldorf
This plant (Figure B-69) consists of four essentially iden-
tical boilers, arranged in pairs. The Dh'sseldorf furnace is primarily for
firing refuse, although there are auxiliary oil guns that can be used for
start-up and when the heating value of refuse is low. The refuse is fired
B-1l8
-------
tJj
I
-
-
...0
I
I
I
I
I
I
I
i I
~ I
i I
, I
; !
I
I
A
I
I~"
-------
B1
Cl
b:J
I
....
N
o
t
A
SEC.'C-C' SEC.'B-B'
FIGURE 8-69. DUSSELDORF REFUSE-FIRED STEAM GENERATOR
- - --
[[O[]]]
SEC. 'A-A'
-------
on a roller grate; as at Stuttgart, only bulky refuse is shredded. The com-.
bustion air can be directed over a steam air-preheater and a feedwater /air-
preheater if heating of this air is desired. Three electrostatic precipitators
treat the combined flue gases of four units. There is also provision for re-
circulating waste gas.
Each steam generator is designed to deliver from 25,500
lb/hr to 35,200 lb/hr of steam at 1,280 psig and 932oF. The roller grate
of VKW design is designed to burn 22,050 lb/hr of refuse with an exit gas
temperature of 4l0oF.
4.
Stuttgart
The Stuttgart plant consists of two units, which are nearly
identical. Both units have one oil-furnace and one refuse-furnace with the
gases combining before entering the convection section.. As with the other
German units considered, there is provision for recirculation of the flue
gases to cool the residue. The units have steam/air and waste-gas/air
(panel design) air-heaters. The steam generators are designed to deliver
204,600 lb/hr steam at 925 psig and 9770F for normal operation with either
oil-firing or combined-firing. The maximum continuous power level is
275,600 lb/hr steam at the same conditions. The boilers were designed
to handle 40,920 lb/hr of refuse having a lower heating value of 2, 159
Btu/lb. The refuse furnace volumes of Units No. 28 and 29 are 17,655 £t3
and 17,443 ft3, respectively. The oil-furnace volume is 13,277 ft3 in both
units.
The noted difference between the two Stuttgart units is the
grate designs. Unit 28 (Figure B-70) is equipped with a Martin grate, while
Unit 29 (Figure B-71) is equipped with a roller grate that evolved from the
Th.{sseldorf (VKW) design. Only bulky refuse is shredded before burning.
Ferrous metals are removed from the residue magnetically.
It is interesting to note that the fly-ash emissions for the
two Stuttgart boilers were expected to be identical, at 1. 81 gr /SCF. The
Martin grate ~urnace, Unit 28, closely approached this figure during TtJV
testing, but the roller grate unit (Unit 29) emitted approximately 25% less
fly-ash under similar test conditions. The grate areas are very similar,
but the Unit 29 underfire air is approximately 35% lower than Unit 28.
Nowak later published test data (Ref. B-I08) that showed Unit 29 to be
producing about 30% more flue gas particulates than Unit 28. Such varia-
tions must be expected, considering the nature of the fuel.
The two Stuttgart units are each equipped with one electro-
static precipitator of Rohtemlihle design, similar to the aforementioned"
Lurgi units.
B-121
-------
tJj
,
I-"
N
N
rs re
SEC. lA-AI
..
I A
l~
$-
SEC.'S- s' SEe.le-e'
FIGURE 8-70.. STUTTGART COMBINED-FIRED STEAM GENERATOR - UNIT 28
-------
b:J
I
-
N
LV
.-.'
rB rC
~
,.
=
=
...~
.t.I.
:=
I
SEe. 'A-':
t:
SEC.IB-B' SEC.' C-C'
. FIGURE 8-71. STUTTGART COMBINED-FIRED STEAM GENERATOR. UNIT 29 .
-------
C.
DATA ANALYSIS; TECHNIQUES AND OBJECTIVES
A prinlary objective was to be able to predict, in quantitative
terms, the nature of the emission problem that could be expected to result
from the application, in domestic service, of refuse- or combined-fired
system elements delineated by the study. This is obviously necessary
in order to specify the required control techniques for such a system.
S~condly, the reviews of both domestic utility practice and German com-
bined-fired practice could form the basis for selecting with confidence
the required control techniques. Finally, industrial experience must be
brought to bear in the course of designing and cost-estimating the control
systems required for each of the study's output-system recommendations.
Several techniques for predicting emis sions from the systems
under study can be proposed. The coal combustion side of the system, and
its respective contribution to the particulate problem, can readily be pre-
dicted from existing technology (Ref. B-109). The refuse-caused component
of the particulate problem might be predicted by employing Stenburg r s (Ref.
B-ll 0) correlations of underfire air velocity vs. particulate emis sions.
Stenburg's correlation appears to have been substantiated by Neis sen (Ref.
B-lll) and Walker (Ref. B-1l2) and is considered by some to be the most
reliable single technique presently available for predicting emissions from
grate-fired refuse. European investigators apparently have never attempted
to relate underfire-air velocity to refus e fly-ash emis sions. Many engineers,
however, feel that other factors influence the generation rates of refuse fly-
ash. These include the effects introduced by overfire air, uplift velocity
above the grate, the presence or absence of a fossil-fuel flame envelope,
and boiler-tube layout. Another factor, and a highly variable one, that
influences fly ash production rate is the presence of discarded ash in the
refuse itself.
The subject units under consideration were all tested under a
variety of seasonal conditions:
Munich Block I May 1965
Munich Block II November 1967
DUs seldorf September 1967
Stuttgart July 1966
Quantitative refuse-compositions for each of the subject tests were not
available. This is unfortunate because European refuse is characterized
by much greater seasonal variations than is refuse in this country. This
is probably due to a greater use of coal for home space-heating in Europe
than is practiced in the U. S. This would result in correspondingly higher
B-124
-------
ash content in European municipal-refuse during winter months. Andritzky
(Ref. B-l13) observed that the Munich Block I plant emitted finer and higher
levels of fly-ash during the winter months. He concluded that this was
caused by the seasonal variation of the ash content in the input-refuse.
Table B-l2 is an overall tabulation of the characteristics of the
plants under consideration. Table B-13 is a detailed tabulation of the pre-
cipitator design data for these plants.
D.
Ti1V PERFORMANCE TESTS
1.
Test Procedures
,
,
I
The TtJV conducted thorough evaluations of the boiler per-
formance of the four selected generator plants. The Ti1V reports, however,
are es sentially designed to demonstrate whether the equipment tested has
met guaranteed specifications. In the context of the present program, the
objective in studying these selected units was, of course, to establish the
feasibility of using refuse as a steam-generator fuel and to determine what
effect such a process would have on the emission of sulfur oxides. Because
of the difference in objectives, the TtJV report data had to be reorganized in
order to emphasize the operational parameters which pertain to this study.
The primary information that was sought from these reports was data dealing
with heat-, material-, and sulfur-balances. Because of its importance,
sulfur balance is discussed in the main body of this report.
The TtiVreports do not develop detailed material balances,
although mass outputs and inputs had been carefully measured. This was done
because it was desired to estimate the heating value of the input-refuse based
on thermal and fuel-consumption properties of the systems. It was felt that
the heterogeneous nature of the fuel would make analytical determination of
the heating value difficult and even then the results would not be accurate.
From an algebraic point of view, the heating value of the fuel is not needed
to determine unit efficiency. .
Since, if
Q =
A
the sum of heat added to the system,
except that from refus e
QS = 'useful steam output
QL = sum of heat losses
QR = heat from refuse combustion
Then
QR = QS + QL - QA.
and the steam generator efficiency is:
QS
.,., -
- QR + QA
B -125
-------
Furnace Type
(Date Commissioned)
Refuse Grate
Type
M.anufacturer
Area, ft2
Charging Rate,
lb/ft2-hr
Btu Release,
Btu/ft2-hr (LHV)
Under-Fire Air,
SCFM
tJj
I
.....
N
CJ"'
Refuse Rate,
Short Tons/Day
lb/hr
Aux. Fuel
Steam Condition
Production
lO.~ Ib/hr
Prcs;,ure, p::;ig
Temp.. uF
(SH/RH)
APC Equipment
Type
Manufacturer
Rated Flow
Collection Efficiency
TABLE B-12
GERMAN PLANT DESIGN DATA
DtJSSELDORF
Block I (2 Units)
MUNICH NORTH
Block II
Combined- Fired
Twin Chamber
(1962)
Recip. /Backward
Feed
Ma rtin
605
91
455,000
660
55,000
Coal
220
2600
1004/1004
Elect. Pptr.
Lurgi
99. 53%
Combined-Fired
Single Chamber
(1966)
Recip. /Backward
Feed
Ma rtin
1035
87
435,000
1060
88,500
Coal
800
2600
1004/1004
Elect. Pptr.
'Lurgi
Various
99+"/0
4 Units
Refuse Only
(1965 )
Roller or Drum
VKW
275
76
378,000
(Flue Gas Recirc. )
250
20,800
None
32
1280
932
Elect Pptr.
Lurgi
Various
99+%
Unit 28
STUTTGART
Unit 29
Combined- Fired
Twin Chamber
(1965)
Recip. /Backward
Feed
Martin
543
81
410,000
34,300
at Full Load
492
41,000
Oil
205
925
977/-
Elect. Pptr.
Rothem{1hle
172,000 ACFM
98%
Combined-Fired
Twin Chamber
(1965)
Roller or DrUlTI
VKW
550
404,000
22,000
a t Full Load
530
44,300
Oil
205
925
977/-
Elect. Pptr.
RothemUh1e
172,000 ACFM
98%
-------
TABLE B-13
ELECTROSTATIC PRECIPITATOR DESIGN DATA FOR GERMAN PLANTS
MUNICH NORTH DUSSELDORF STUTTGART
B lock I Block II Unit Z8 Unit Z9
Number of Boilers/pptr 1 2 1 1
Number of Ducts 34 84 28 42 42
Duct Width, in. 9.5 8.5 8.75 8.75
Duct Height, ft. 24.6 27.4 20.6 25.4 25.4
Duct Length. ft. 29.1 31.5 18.9 16.4 16.4
tP Total Proj CoIl Area, ft2
I 48,700 21,800 35,000 35,000
......
N 2
-J Inlet Cross-Sect Area, ft 658 1810 406 780 780
Transformer-Rectifier Sets Two-6S0 ma Two Two One 500 ma . One 500 ma
Operating Voltage, kv d-c (max, ) 76
Number Bus Sections 2/Series 2/Series x Z/Parallel Z/Series Z/Series 2/Series
Design Gas Velocity (max.). itl see 3.4 3. 16 3.7 3.67 3.67
-------
---I
The TtJV tests were conducted in the following manner.
The ten1.perature, volume- rate, hun1.idity, and pres sure of the cOl1.1.bustion
air were measured. If this air were heated by a source that was not in-
cluded in the control volume, the heat- content of the air would then have
a heat-input term associated with it. The mass-rate of refuse burned was
usually determined from a calibration curve of the current drawn by the
refuse-crane vs the load lifted. The instantaneous current drawn by the
crane at a specific height under known loads furnished the values that were
used to plot the calibration curve.
The temperature of the residue was measured at the end
of the grate by thermocouples. In units where the residue falls from the end
of the grate into a quench tank, a heat input term is calculated to account for
the water that evaporates from this tank and enters the furnace. The mass-
rate of residue produced was measured and samples of the residue were
analyzed to determine the level of combustibles still present after firing.
The heat value of uncombusted combustible material and the sensible heat
of the residue were then expressed as heat-loss terms.
The mas s -rate, temperature, and combustible content of
the fly ash were also measured. This was done in two ways. In some tests
the mass of the collected fly ash was measured and samples of the waste gas
were taken and analyzed. In the other method, an efficiency of the dust col-
lector was assumed and the mass-rate of the fly ash in the raw gas was cal-
culated using the measured mass of the precipitated fly ash. The moisture
of the fly ash was also measured.
The levels of CO, COZ' and Oz were measured using an
Orsat tester. The remainder of the waste gas was assumed to be NZ (dry
basis) for heat-balance purposes. The humidity of the waste gas was deter-
mined by drawing a sample of the waste gas through a cooler and into a Wulf
bottle. From the weight of the condensate, the humidity of the waste-gas
could be calculated.
Because the German practice is to establish the lower
heating value, the heat loss from the wet waste gas was calculated as
follows:
Q -
L(waste gas) -
[~M. Cp ] TZ - [~M. Cp ] Tl
1 i(Tz) 1 i(TI)
where:
specific heat of each constituent of the waste gas
Cpo =
1
T Z = temperature of waste gas
Tl
M.
1
= reference temperature
= mass of each constituent of the waste gas
B-IZ8
-------
The heat los s due to the conduction and radiation of the
boiler was estimated from standard charts, and the calculation of steam
energy was done in accordance with usual practice. If a fossil fuel were
fired with the refuse, its heat-input was calculated on the basis of an ana-
lytically determined heating value.
At Stuttgart, five tests were performed on each boiler.
Three tests were performed using oil only as the fuel. This report con-
sidered only the two combined-firing tests done on each unit. The duration
of each combined-firing test was 7.5 hours. One combined-firing test was
accomplished at maximum continuous power-level (275,000 lb/hr steam), .
and one was at approximately half maximum continuous-load (165,000 lb/hr
steam) for each boiler. All the combined firing tests were performed at
the maximum refuse mass-rate. At DUsseldorf, one 24-hour test was
performed. The power level of the unit was kept at maximum continuous-
load (35,200 lb/hr steam). No oil was fired during this test.
2.
Results
In all of the tests the total mass-output was found to be
greater than the mass input. All the units tested were of balanced-draft
design and thus the extra mass was attributed to air-leakage into the boiler.
The heat-balance and thermal-efficiency data in the TtJV
reports were calculated on a lower heating value basis. Conversions were
therefore made in the TtJV heat-balances to make them consistent with u. S.
(higher heating value) practice. Additional heat-loss terms were also added
to include the heat of evaporation of the water arising from the moisture and
available hydrogen present in the fuels.
The percentage of moisture in the refuse was determined
from water-balance derivations. The sum of the moisture and the water
arising from the hydrogen in the refuse was found by subtracting all the
water inputs (except that from refuse) from the water outputs. There are
two methods for determining how much of this water is actually derived
from the moisture in the refuse. One method is to assume a certain per-
centage of hydrogen in the refuse and to calculate the amount of water that
would be formed from this hydrogen during combustion. Another method
is to assume a heating value for the refuse. Using this heating value and
the calculated lower heating value, the percent of combustible in the refuse
can be determined. The ash-content can be derived from the mass-measure-
ments of residue and fly ash; the remainder would then represent the percent
of moisture in the refuse. The percent of moisture in the refuse was usually
determined by the latter method.
The results of the TtJV tests and the data conversions
that were employed, as described above, are summarized in Tables B-14
through -17. The first two present material-balance data while the last
two consist of heat-balance information. In the following section, data a.re
presented on the dust collector tests which were simultaneously conducted.
B-129
-------
TABLE B-14
SUMMARY OF EFFICIENCY - TEST DATA FOR MUNICH UNITS - MATERIAL BALANCES
Plantl Unit MUNICH NORTH BLOCK I MUNICH NORTH BLOCK U
Test :-:urnber 5 6 4 5 6 7
Firing Mode Coal Only Refuse + Coal Refuse Only Coal Only Refuse Only Refuse t Coal Refuse t Coal Refuse. Coal
Input:
Combustion Air. 1b/hr 1 286.016 358.759 225. 100 950,000 283,412 1,047,960 1,003,070 5Jl,690
Au..... Fuel. 1b/hr 25, 199 15,388 0 74,580 0 57,280 56,460 16,755
Combustibles. .,. 83.1 84.4 85.9 86.6 86.7 86.6
Ash. % 6.2 5.9 6.4 6.6 6.2 6.5
Moisture. 'II> 10.7 9.7 7.7 6.8 7. I 6.9
Refuse, lb/hr 0 59,337 57,536 0 100,310 94, 140 86,640 38.845
Combustibles. .,. 26.3 25.6 35.2 32.3 31.5 30. f,
Ash. ~. 41.2 30.0 36.8 36.9 44.6 39.8
Moisture. r. 32.5 44.4 28.0 30.8 23.9 29.6
Output:
tP Wet Waste Gas. Ib/hr 376,560 394.544 287.970 1.030,850 366,820 1,163,130 1,119,000 53 I, 820
I Moisture Content. wt-"'2.
'..... 2.0 10.0 12.4 4.4 12.6 5.8 6.0 9.8
i (.oJ
10 Waste Gas Comp., Dry Basis:
I
OZ' 'io 6.30 6.70 11.88 14,35 6.50 5.75 5.45 6.70
C02' <4f. 13.15 13.00 8.87 4.90 13.45 13.85 14.45 13.00
502' a;., 0.05 0.03 0.019 0.048 0.106 0.094 0.09 0.09
1'2' '11> 80.50 80.26 79.22 80.70 79.94 80.31 80.01 80.16
CO. % 0.007 0.01 (HC1 = 0.046":
Raw Flue Gas Fly Ash, 1b/hr
Ash 958 3,039 3,362 2,384 1,239 2.463 5,478 2,425
Combustibles 375 584 196 82 190 214 304 408
FUr.1ace Residue. Ib/hr
Ash (e:«:ludill8 metals) 19,888 19,116 30,001 28,418 29, 133 25,568
Combustibles 690 417 1,265 1,177 2,314 1,250
Metal (total) 1,197 1,193 2,815 3,500 3,585 3,v05
1) Wet basis, except for Stuttgart units.
2) Other gas compositions are in vo1-0/0; solid compositions are in wt-,,/..
-------
TABLE B-1S
SUMlvlARY OF EFFICIENCY - TEST DATA FOR DUSSELDORF AND STUTTGART UNITS -
MATERIAL BALANCES
~ant/Uni.!. DUSSELDORF STUTTGART UNIT NO. 28 STUTTGAR T CJ\:IT NO. 29
Test :>:umber 4 5 4 5
Firin~ Mode Refuse Only Oil Only: ReCuse + Oil 'ReCuse + Oil Oil Only Refuse + Oil ReCuse + Oil
In:>ut:
Combustion Air, Ib/hr I 92,358 291.000 365. 113 252,424 320,769 345.020
252.558
Aux. Fuel, Ib/hr 0 19.392 12.090 6,505 19.6n 13.466 6.116
Combustibles. %
Ash, Cfo
Moisture, ~.
Refuse. Ib/hr 23.192 0 53. 131 46,385 0 49.240 47.437
Combustibles, % 33.9 43.6 30.5 30.3 31.8
Ash, :0 33.7 25.9 28.5 31.3 30.6
b:1 ~ioisture, % 32.4 30.5 41.0 38.4 37.6
I ~
....
UJ Wet Waste Gas. Ib/hr 113.007 283.220 421,917 303.860 313,050 412.032 312.273
....
Moisture Content, wt-%2 9.9 8.0 10.3 11.2 5.9 11.3 10.5
Waste Gas Camp.. Dry Basis:
02.' ,:" 11.20 1.43 4.42 6.26 1.35 5.04 7.42
C02' % 8.41 14.59 13.33 12.14 14.67 12.90 11.41
SOl' % 0.046
X2' % 80.30 83.98 82,. Zl 81.59 83.90 82,.06 81. 17
CO, 'fo (HCI = 0.046%) 0.04 0.01 0.08
Raw Flue Gas Fly Ash, Ib/hr
Ash 1,02,8 1.030 605 1.383 1.394
Combus tible s 7Z 143 44 120 120
Furnace Residue, Ib/hr
Ash (excluding metals) 6.078 n.,2,41 10.979 12.095 11.411
Combu:; tible 5 564 185 32.6 345 375
Metal (total) 728
Separated Ferrous Metal 1.056 1,005 1,490 1.303
I) Wet basis, except for Stuttgart units.
2) Other gi:l8 c<.rmpotiiliuns arc in vol..%.: solid compositions are in wt..%.
-------
TABLE B-16
SUMMARY OF EFFICIENCY - TEST DATA FOR MUNICH UNITS - HEAT BALANCES
Plant/Unit MUNICH NORTH BLOCK I MUNICH NORTH BLOCK II
Trst Xumb..r 5 6 4 5 6 7
Firing Mode Coal Only Refuse + Coal Refuse Only Coal Only Refuse Only Refuse + Coal Refuse + Coal Refuse + Co...l
Int"'t (.."cI. r..(u... I. 103 Rtu/hr
Hut (rom Aux. Fuel (HHV) 322.689 200, 100 0 994, 120 0 765.500 758,600 226,360
:;""..bl" 11"..1 ..1 .'\u". 1-"ud
Atomi:er Steam'
Air Hut
SI.....n H""t (rom Re8ldue
tP .otal (A) 322,689 200,100' 0 994, 120 0 765.500 758.600 226,36(;
I 103 Btu/hr (D) Z87.40Z 276,207 92. 044 881,020 223.547 890.660 856.910 391,296
..... Ste."" Output,
W 103 Blu/br (e)
N Losses,
Wel Wute Ga. 13,602 21.850 15.780 71, 779 33,383 87,682 1'4.190 37.801
Heat of Vap. ot Moilture Ie Comb. 16,272 45.796 31,650
Fuel - HZ 42,750 47,470 91,723 65. 130 64, 966
Res~due &. Fly A.h 5.873 25.769 17.033 939 16. 438 17.191 22. 130 21.653
Conduction &. Radiation Z,165 2,284 2.161 2.816 2,709 2,994 2,830 2,661
Total Losses (C) 37.913 95.699 66.624 118,284 100.000 199.590 174,280 127,081
Output, 103 Btu/hr (B + C) 325,315 371,906 158.668 999,304 323.547 1.090.250 1.031,190 518,377
Thermal Efficiency ( 'I), r. 58.0
11('(lBlB + C) 88.4 74.3 88.2 69.1 81.7 83.1 75.5
Refuse Input. Ib/hr (D) 0 59.337 57,536 0 100,310 94. 140 86,640 88.845
Refuse He:>ting Value (HHV - C.J.c'd), Z.900 2.757
Stuilb (B + C . AID) 3,225 3.450 3,146 3.287
St..;>...." Production. 1061b/hr 224 214 82 775 752 315
-------
TABLE B-17
SUMMARY OF EFFICIENCY - TEST DATA FOR DUSSELDORF AND STUTTGART UNITS -
HEAT BALANCES
Plant/Unit DUSSELDORF STUTTGART UNIT NO. 28 STUTTGART UNIT NO. 29
Test Number 4 5 4 5
Firing Mode Refuse Only Oil Only Refuse + Oil Refuse + Oil Oil Only Refuse + Oil Refuse + Oil
Input (excl. refuse), 103 Btu/hr
Heat from Aux. Fuel (HHV) 0 365.217 228,091 122,738 370,079 253,344 115,057
Sensible Heat of Awe. Fuel 1,543 1,098 607 1,309 1,091 622
Atonlizer Steam 178 139 147 127 159 155
Air Heat 543 6.175 6,484 5.564 9.300 5,667 3,708
Steam Heat from Residue 480 1.507 1,646 2,546 2,411
to 1.023
I Total (A) 373.113 237.319 130.702 380.815 262.807 121,953
....... Steam Output. 103 Btu/hr (B)
W 40,478 323. 149 324.280 198. 166 335.431 314.591 192.681
W
Losses. 103 Btu/hr (C)
Wet Waste Gas 12. 964 25.333 38.079 27,288 21 .079 40,022 30.714
Heat or Vap. or Moisture &. Comb. 10,501
Fuel - H2 24.334 40.846 31.765 20.836 43.222 29.937
Residue 8< Fly Ash 7.567 103 6.575 6,575 1.257 8.086 8. 162
Conduction 8< Radiation 1,562 1.642 1.701 2.114 1.654 1,590 1.685
Total Losses (C) 32, 594 51,412 87.201 67,742 44,826 92,920 70.498
Output. 103 Btu/hr (B + C) 73.072 374.561 411.481 265,908 380.257 407.511 263. 179
Thermal Efficiency (1). "1.
(100B/B + C) 55.4 86.3 78.8 74.5 88.2 77.2 73.2
Refuse Input, Ib/hr (D) 23.192 0 53. 131 46.385 0 49.240 47,487
Refuse Heating Value (HHV - Calc'd).
Btu/lb (B + C - A/D) 3.107 3.278 2.915 . 2.939 2,974
Steam Production, 1061b/hr 272 270 165 279 263 161
-------
E.
EMISSION - CONTROL (ELECTROSTATIC PRECIPITATOR)
EQUIPMENT
1.
Performance Characteristics
With the exception of gaseous emission control, the legis-
1ation and enforcement aspects governing emission control in Germany are
similar to those of this country. The specification for allowable dust emis-
sion is, however, more strict. Regulation VDI-2ll4, November 1966, limits
incinerators of over 20 tons per day to an absolute fly-ash emis sion of 150
mg /Nm3 (0. 061 gr /S CF) uncorrected for C02' Stack opacity requirements
are also made based on Ringlemann indices.
The firm of Lurgi Apperatebau of Frankfurt was com-
missioned to design the fly-ash collection system for the first combined-
fired (coal-pIus-refuse) power boiler (Munich North Block I). Due to
considerations of particle size and fly-ash resistivity, Lurgi felt that the
refuse-derived component of the fly ash would be somewhat easier to control
via electrostatic precipitation than that from low-sulfur coal.
In Europe, precipitators for low-sulfur coal fly ash are
typically operated under 2600 F. This is well below the flue gas temperatures
around 3100 F as sociated by some U. S. observers with peak resistivity
and, thus, minimum collection efficiency. Lurgi, however, expected refus e
fly ash to be more tractable and regarded operation at peak-resistivity
as acceptable. In keeping with this, Lurgi I s performance guarantee
on the combined-firing system was based on a precipitator design migration-
velocity (precipitation rate) of 0.222 ft/sec. This compares to a value of
0.130 ft/sec for coal-only firing of the same system. The latter value
dictates that a precipitator be sized 50% larger than would be required for
a combined-firing installation. The 0.222 ft/sec design migration-velocity
for combined firing resulted in a guaranteed collection-efficiency of 99.25%.
In actual test at Munich Block I, collection performance was measured at
99.75%, corresponding to an actual migration-velocity of 0.301 ft/sec.
The operation on coal-only was also much better than anticipated in the
guarantee. Compared to a design migration-velocity of O. 130 ft/sec for
a guarantee collection efficiency of 97. 54%, the unit was tested at 99. 56%,
corresponding to an actual migration velocity of 0.203 ft/sec.
Lurgi guaranteed, on the basis of an average design
11
migration-velocity of 0.363 ft/sec, that the Dusseldorf units would perform
at 98.90%. Under actual test conditions (gas temperatures of 4500 - 4600 F),
the precipitators were found to have a 99. 68% collection efficiency,
corresponding to an average actual migration-velocity of 0.402 ft/sec.
At the third installation, Munich North- Block II, Lurgi
decided that for combined firing at similar temperatures the precipitator
design migration-velocity could be raised from 0.222 ft/sec (design,
Block I) to an average of 0.265 it/sec. This resulted in guaranteed collection
B- l34
-------
efficiencies of 99. 5% and above. Under actual test, the precipitator per-
formed at 99. 72% and higher, corresponding to an average actual migration-
velocity of 0.295 ft/sec. This value is slightly lower than the performance
of the Block I precipitator (0.301 ft/sec actual). presumably because of the
lower dust-output.
For coal-only firing at Block II, Lurgi I s guarantee was
again improved, in spite of the fact that an operating temperature of 31 OOF
(peak resistivity) was permitted. The migration-velocity was increased to,
0.153 ft/sec as compared to the design-value of O. 125 ft/sec for Block 1.
Under actual test, however, the unit not only met the guarantee but per-
formed better at 3l00F than the Block I units did at 2600F. It was demon-
strated from these test data that the fly ash produced in these units exhibited
a lower temperature peak resistivity than is considered typical (3000 - 3l00F)
for this country. This is shown in Figure B-72.
It is also interesting to note that U. S. investigators (Ref.
B-1l2) have reported fly-ash resistivity values' of lOll ohm-em, at approxi-
mately 4100F, for refractory-wall, municipal refuse-incinerators. Corres-
ponding values for European water-walled furnaces are reported (Ref. B-I07)
at 6 x 107 ohm-cm at 4320F. A comparison of the precipitation rates is shown
in Figure B -73. This significant difference is probably related to the compo-
sition of the respective fly- ashes.
The relationship of fly ash resistivities to temperatures
for German fly ash from both low-sulfur coal and refuse appears to be sig-
nificantly different from that of similar U.S. counterparts (Refs. B-112 and
B-114). This indicates that pollution control design parameters for any pro-
posed combined-fired systems for use in this country cannot be directly
based on European practice.
Values of resistivity vs. temperature for U. S. plants dic-
tate that a minimum gas temperature of 4500F be selected for electrostatic
precipitator operation with municipal-refuse fly ash, whether heat recovery
is practiced or not. These data also indicate that precipitators must be more
conservatively sized than are European systems.
2.
Design Facto~
The materials of construction of the precipitators and flue
work in the German precipitators are plain carbon steel. Fly ash collecting
and storage hoppers are pyramidal. These and the dry, pneumatic, ash-
handling systems are typical of those favored in utility practice, but in sharp
contrast with, U. S. refractory-incinerator practice. Experience in the latter
field indicates that dust transport properties are such that live bottom devices
are required under electrostatic precipitators. These may take the form of
trough-hoppers with screw-conveyors, chain-drag equipped flat-bottoms,
or agitated slurry-ponds integral with the precipitator. The operation of
B-135
-------
0.1
o
Q)
(f)
.......... .
-
lL. 0.2
-
3
-
w O.3~
....
-------
0.1
o 0.2
ell
en
......
-
u..
..
-
~ 0.3
-
w
.....
<{
a:::
z
o 0.4
.....
<{
.....
f1.
<.) 0.5
w
a:
Q.
0.6
o
o MUNICH BL I, REFUSE ONLY
o MUNICH BLII,REFUSE ONLY
o DUSSELDORF, REFUSE ONLY
o STUTTG ART.REFUSE a 01 L
100
200 300 400
GAS TEMPERATURE,oF
500
FIGURE 8-73. PRECIPITATOR PERFORMANCE VS GAS TEMPERATURE -
GERMAN AND U.S. DATA
B-137
-------
domestic refractory units has also dictated that more sophisticated materials
of construction be used throughout to combat corrosion. Finally, extensive
gas tempering must be employed (Ref. B-llS) to depress gas temperatures
if lower cost materials of construction are to be used successfully.
In both domestic and European utility practice, reliability
and availability considerations promote the use of multiple electrical sections
within electrostatic precipitators. In the event of an electrical malfunction,
sectionalization permits the isolation and shutdown of only *e impaired sec-
tion. All of the German precipitators discussed here are equipped with two
electrical sets, or transformer-rectifiers, each with its own control system
that automatically regulates power-input to maintain preset levels of electric
field-intensity or density. The exact feedback conditions are not detailed in
the available data in the case of the German control systems. It is known,
however, that European precipitator manufacturers equip their U. S. in-
stallations with automatic voltage controls that maintain a preset level of
sparking within the precipitator. Random or occasional sparkover is con-
sidered a good indicator of optimum field- strength and power-input.
Somewhat in contrast to U. S. -manufactured equipment,
the European precipitator design-approach aims at a more conservative
migration velocity by using somewhat lower field intensities. Thus, the
size of the precipitator must be increased commensurately. As a result
of this, lower gas velocities, 3 to 4 ft/sec, are employed in combined-fired
applications. U. S. designers would typically specify gas velocities of 4 to
4-1/2 ft/sec for refractory incinerators. It must be cautioned, however,
that gas velocity is selected for a discrete particle size distribution so
that re-entrainment problems are minimized.
One final difference that has been historically observed
between European and U. S. precipitator designs is the degree of electrical
sectionalization. Two electrical sections in series were standard in the
German units studied. U. S. suppliers would incorporate 3 or 4 sections,
in series, for similar requirements.
3.
Performance Guarantees
The European performance guarantees state that collection
efficiency must be expected to decrease with decreasing inlet dust-loading,
presumably because re-entrainment losses remain fairly constant in the
face of.varying loadings. Correction curves are also presented that show
how collection efficiency will increase with decreasing flow rate. This is
due to higher residence time in the precipitator. The guarantees further
state that gas temperature will be maintained through certain limits, or
performance will decrease. Finally, the combustible content of the ash
must be maintained within certain limits, or else performance will be
impaired. This follows from the effects carbon combustibles are known
to produce on ash resistivity.
B-138
-------
The guarantee situation on the domestic scene is seemingly
not as sophisticated. U. S. suppliers normally guarantee a performance level
at one point, and not through a range of operating conditions. However, the
actual selection of design parameters is more of a proprietary art in the U. S.
than in Europe. The European literature abounds with information on resis-
tivity as a function of process variables (e. g., Refs. B -115 to -118) and.
migration-velocity selection.
F.
TtJV DUST COLLECTOR TESTS
With one exception, precipitator inlet and outlet dust determina-
tions were done by isokinetic sampling. TDI test methods are used by the
TtJV. Four alternative sampling trains are employed, depending on the
velocity of the flue gas at the point of sampling. The VDI tept procedures
conform closely with ASME Power Test Codes PTC 21, 27, and 28. In the
case of the DUsseldorf tests, flue layout prohibited reliable sampling. In-
let loading was therefore calculated on the basis of the outlet loading and
the precipitator hopper-catches. The TtJV calculate dust collector efficiency
on a mas s -differential basis:
Eff" " - inlet concentration-outlet concentration
lClency - " 1 "
In et concentrabon
This is in agreement with U. S. practice, except that in this country concen-
tration values are always corrected to standard gas conditions (32°F and 760
torr). The TtJV data were not consistently in this form. Where neces sary,
therefore, dust concentrations were corrected to standard gas conditions
but not to a standard C02 level. An overall summary of the dust collector
test data is presented in Tables B-18 and -19. The tabulation includes
calculated data comparing the design vs. actual precipitator performance.
Precipitation rates, electrical energization data, and gas velocities are
included. The tests shown were all performed at full boiler steaming -load.
1.
Particulate Emis sions
a.
Concentrations
Measured fly ash concentrations for the subj ect plants
ranged from a minimum value of 1. 10 gr /SCF for the Stuttgart Unit 29 toa
maximum of 8.64 gr /SCF for Munich Block I while in combined-firing (refuse
+ coal) operation.
If one subtracts O. 15 gr /S CF for the oil-derived com-
ponent of the Unit 28 Stuttgart lowest fly ash emissions (Test No.1, Table
B-19), the resultant value for the refuse-derived fly a.sh emissions is 1. 62
gr /SCF. This compares with a measured emis sion of 1.66 gr /S CF for Munich
Block II Cfest No.7, Table B -18) when firing refus e-only. Both units are
equipped with Martin reciprocating grates. The Munich Block II emis sions
B -139
-------
TABLE B-18
SUMMARY OF DUST-COLLECTOR PERFORMANCE DATA FOR MUNICH UNITS
Plant/Unit MUNICH NORTH BLOCK I MUNICH NORTH BLOCK II
Test Number 1/ I 1/2 2/1 2/2 3 4
Firing Mode Coal Only Coal &: Refuse Refus e Only Coal Coal Coal Coal +40TPH Coal+40TPH Coal+4 TPH Refus e
(Low Load) Refuse Refuse Refuse Only
Rated Gas Volume. 103 ACFM (OF) 98(284) 98(284) 132(320) 132(320) 343(302) 343(302) 343(302) 423(338) 432(338) 432(338) 432(338)
Act~~l~t)~ YooJ~~F~ea8ured at Pptr IIO( 247) 113(257) 147(310) 147(310) 108(315) 346(308) 348(313) 245(284) 419(324) 432(336) 384(326) 403(328)
Percent of Rating 112 115 III III 101 101 71.3 96.8 100 88.7 93.5
Anticipated Pptr Inlet Dust Cone. grlSCF 1.97 1.97 1.97/6.95 1.97/6.95 6.95 2. 19-8.75 2.19-8.75 2.19-8.75 2.19-8.75 2. 19-8.75 2. 19-8.75 2. 19-8.75
Actual (Test) Pptr Inlet Dust Cone. grlSCF 2.39 2.44 5.12 8.64 6.76 1.18 1.51 9.51 3.06 3.06 3.24 1.66
Actual (Test) Pptr Outlet Dust Cone,
gr/SCF - 0.0105 0.0325 0.0128 0.0178 O. 00774 0.0089 0.0166 0.0060 0.0103 0.00503 O. 00896 0.0133
Guaranteed Collection Efficiency I 97.94 97.49 99.25 97.97 98.00 99.55 99.55 99.50 99.72 99.54
Actual (Test) Collection Efficiency, % 99.56 98.67 99.75 99.79 99.89 99.24 98.90 99.37 99.65 99.84 99.72 99.20
IJj Pptr Design Gas Velocity at Rated
Volume. £tl see 2.48 2.48 3.35 3.35 3.15 3.15 3.15 3.98 3.98 3.98 3.98
I
...... Pptr Actual (Test) Gas Velocity, ft/sec 2.77 2.86 3.714 3.714 2.73 3.19 3.21 2.26 3.86 3.99 3.55 3.72
"'" Relative Pptr Size (Design) Based on
0 Rated Flow. see/it 29.80 29.80 22.07 22.07 25.41 25.41 25.41 20.18 20.18 20.18 20.18
Relative Pptr Size (Actual) Based on
Actual Flow, sec/ft 26.68 25.88 19.91 19. I 27.10 25.22 25.05 35.64 20.33. 20.16 22.74 20.58
Precipitation Rate (W):
(design). it/see 0.130 0.124 0.222 0.153 0.154 0.213 0.268 0.263 0.291 0.267
(actual), it/see 0.203 0.167 0.301 0.323 0.251 0.193 0.180 0.142 0.271 0.319 0.258 0.235
Pptr ~lectrical Energization Data:
A} Secondary Voltage Inlet
(Inlet/Ootlet), kv 41.2/44.4 40.8/43.7 30/34 31/34 32/33 38.2/37/2 37.2/37.8 32.2/32.6 30.5/32.2 32.2/32,2 32,2/32.8
B) Secondary Amperage
(lnletl Outlet). ma 260/308 240/381 600/560 640/650 640/650 850/940 585/775 750/720 735/870 600/660 620/684
C) Input Power (Inlet/Outlet). kw 10.7/13.7 9.79/16.6 18.0/19.0 19.8/22. I 20.5/21.4 26.5/34.9 21.8/29.3 24.2/23.5 22.4/28.0 19.3/21.3 20.0/22.4
D) Power Density (Inlet/Outlet),
Watts/ 103 ACFM 103/126 90.6/154 128.6/136 141.7/157.9 198.8/208 76.9/101 62. 5/84. 2 57.8/56.2 51.9/64.8 50.3/55.3 49.5/55.7
E) Power Density (Inlet/Ootlet),
Watts/Ft2 0.220/0.281 0.201/0.342' 0.370/0.391 O. 407/ 0.454 0.421/0.440 o. 183/0.241 o. 150/ 0.202 0.167/0.162 o. 155/0.193 o. 133/0. 147 o. 138/0. 155
F) Field Strength (Inlet/e>,;tlet),
kv/ in. 0.87/0.94 0.86/0. 9Z 0.63/0. 7Z 0.65/ 0.72 0.68/0.70 0.80/0.77 0.77/0.80 0.68/0.69 0.65/0.68 0.68/0.68 0.68/0.69
I. Corrected for test conditions per Manufacturer's correction factors.
-------
r -
I
TABLEB-19
SUMMARY OF DUST-COLLECTOR PERFORMANCE DATA FOR Dlh;~ELDORF AND ~TU'l''l'GAH'l' UNlT~
PI.."t/Unit
DUSSELDORF
2
Refusc ReCusc
93(500) 93(500)
91(455) 92(468)
97.7 98.9
3.94 3.94
4.81 5.69
0.0158 0.0184
98.85 98.95
99.67 99.68
3.82 3.82
3.74 3.77
14.00 14.00
14.32 14. 16
0.408 0.319
0.399 0.406
31.5/29 31/29
265/267 313/310
8.3/7.7 9.7/9.0
91.7/85 105/97.7
0.401/0.372 0.466/0.432
0.74/0.611 0.73/ 0.611
Test (\umber
Firing :.ltJdt:
Rated Gas Volume, 103 ACFM (OF)
Actual Gas Voh,lme (Measured at Pptr
Outlet), 10) ACFM
Percent of Ratin~
Anti,.ir"<.J.tct! l'I.ltr Inl-.;l DUbt C(JIH':, grlSCF
Ac~ual (Test) Pptr Inlet Dust Conc, gr /SCF
Actual (Test) Pptr Outlet Dust Canc
gr/SCF - '
Gua:-;,ntc.:cd Collection Effi<.:icncy 1
Actual (Test) Collection Efficiency, '?o
f-'ptr LJt.'si~;r. (i<.1S Velucity at Ratcd
Volurroe, ft/sec
tJj
I
~~lr Al"..tU~1 rrt:~l) (.;<4::) Velocity, fl/tJt:c
.....
,.j::.
.....
Rdative P;>tr Size (Design) Based on
Rated FIr)'"". se(;/ft
RclGtiv(: Pptr Size (A<.;:'ual) ilased on
Ar:t\.:al Flnw. see/it
Pr<:ci;>itation Rate (,-'0):
(rh~sil.:n). ft/fH'('
(actual). ft/sec
pptr Electrical Energization Data:
A) Seconda ry Valtas" Inlet
(Inlct/Outkt!, kv
B) Second~ry AmfJcragc
(Inlet/Outlet). ma
C) Input P"wcr (Inlet/Outlet). kw
D) Powcr Den.ity (Inlet/Outlet),
Watt./103 ACFM
E) Power D"nsity (Inlet/Outlet).
Watts /ftl.
F) fOld" Strength (Inlet/Outlet),
kv/ill.
I.
CfJrr-:c.tcJ (ur tctfl (.;onuili<.roti per rnanuf,;u.:lurcr'e;, ,",orrcclLun facLol"ti.
STUTTGART
Unit 28 Unit 29
2 3 4
Refusc &. Oil Ilcfl\sc &. Oil Rdusc &, Oil R,'fusc &, Oil
172(410) 172(410) 172(410) 172(410)
164(375 133(375) 169(362) 117(360)
95.2 77.4 98 67.6
1.81 1.81 1.81 1.81
1.67 1.83 1.47 1. 10
0.0169 0.0207 0.0210 0.00283
98.5 99.5 97.9 99.5
98.22 98.87 98.57 99.74
3.68 3.68 3.68 3.68
3.51 2.85 3.61 2.49
12. 17 12.17 12. 17 12.17
12.79 15.73 12.42 18.02
0.328 0.435 0.317 0.435
0.315 0.285 0.342 0.330
26.5/21. 8 26.8/22.4
484/588 503/575
12.8/12.8 13.5/12.9
79.7/79.6 121/116
0.366/ O. 366 0.385/0.368
0.6110.50 0.61/0.51
-------
are lower than would be anticipated on the basis of underfire-air considera-
tions alone. This is undoubtedly due to a superior burn-out being effected
in this boiler.
In considering the VKW roller grates units at Dllssel-
dorf ant Stuttgart (Unit 29), strikingly different emissions (refuse-only firing)
are apparent: a measured average of 5.25 gr/SCF at Dllsseldorf vs. 1. 13
gr /SCF at Stuttgart. The latter figure includes a O. 15 gr /SCF subtraction
for oil-derived ash.
An absolute value of 22, 000 SCFM underfire air at
full load is available at Dllsseldorf. The heat-release rate of the Stuttgart
roller grate is lower than for the DUsseldorf grate, so that a lower refuse-
derived level of emissions can be expected at Stuttgart. The wide spread
between these values (5.25 vs. 1. 13 gr/SCF) is apparently not solely ex-
plicable on the basis of underfire-air. Other variables, such as furnace
velocities and time vs. temperature profiles, are suspected as being
contributory.
A final interesting comparison, mentioned earlier,
is that between the Martin and VKW grates in the otherwise-identical Stutt-
gart units. The roller-grate unit produces 25% lower dust concentrations,
while being fired with 30% less underfire-a.ir.
All of the foregoing tends to support the conclusions
of Stenburg (Ref. B-llO), Neissen (Ref. B-lll), and Walker and Schmitz
(Ref. B-ll2); that is, the type of grate, and even the degree of agitation the
fuel is subjected to, is of little or no consequence in influencing particulate
levels. They feel that underfire-air velocity and refuse composition, ex-
pressed as SCFM/ft2 of grate, vs. emissions per lb of combustible burned,
is the main factor in determining particle loading.
The velocity of underfire-air is not, however, the
only controlling parameter. The low emissions of the Munich Block II unit
and Stuttgart Unit 29 cannpt be e~plained on that basis. Clearly, furnace
geometry plays a significant role in determining particulate emissions.
Qualitatively speaking, however, analysis of the Tt1V data indicates that
lower furnace gas -velocities and higher residence-times result in signi-
ficantly lower particulate emissions.
b.
Fly-Ash Sizing and Combustibles
Particle size distributions were expressed by the
TtJV (Refs. B-I04 to -108) in suspension-velocity categories. These data
were therefore converted to equivalent particle diameters based on a sus-
pension velocity of 0.6 em/see for a 10fL particle. Additionally, actual
sieve and Bahco analyses had been performed on integrated hopper samples
from Munich Block II and DUs seldorf by other investigators (Ref. B-lll).
These data are combined in Table B-20. The values range from 5% «lOj.L)
for Block II units, to 20% «10j.L) for DUsseldorf.
B-l42
-------
b:I
I
-
~
w
TABLE B-20
PROPERTIES OF FLY ASH FROM GERMAN PLANTS
Munich North Block I
Munich North Block II
Dus seldorf
Stuttgart 28
Stuttgart 29
1) - Source: Ref. B-Ill
2) - Source: Ref. B-119
P article Size Dist.
% Less Than Indicated
Size ( p. )
Not Available
5% (10)1
13% (10) (TUV Test-I)
23% (10) (TUV Test-2)
20% (10) 1
Not Available
Not Available
% Combustibles
Bulk Resistivity
(A) = Refuse Only
o
(B) = Combined Firing Ohm - cm ( F)
6. 5% (A)
15% (B)
20% - 30% (B)
Not Available
2
3.4% (B)
2 X 109 (320)1
6. 6% (A)
6 X 107 (432)
9.7%(B)
Not Available
8.3% (B),
Not Available
-------
Refuse fly-ash emitted during grate combustion might
he expected to become coarser as the input-rate is increased. This follows
from the idea that the bed emits greater amounts of material (and of increasing
size and mass ranges) as the underfire air is increased. This prediction is
complicated by burnout considerations, however, The percent combustibles
in the fly ash, as the latter elutriates from the bed, will also influence the
ultimate size of the particles which leave the furnace. Finally, furnace geo-
metry also determines the degree of ultimate burnout achieved for any given
particle in suspension.
The lower fly ash emissions from either Munich Block
II or Stuttgart would be expected to be characterized by low combustible con-
tents and small particle diameters. As the data in Table B-20 indicate, this
is not completely true. The Block II unit furnished the lowest emission rate,
and the best apparent burnout (lowest combustibles). Despite this, the Block
II ash is reported as being coarser than that from other sources. It is possible,
of course, that the hopper-catch samples were not representative.
c.
Ash Resistivity
Absolute values for fly ash resistivities were not
given in the TtJV test reports. Values for Munich and DHsseldorf have been
reported by another investigator (Ref. B-120) and were included in Table
B-20.
These values were determined using integrated hopper-
catch samples from the respective installations. Again, the samples cannot
be considered as being truly representative. Owing to the selective behavior
of the precipitator, resistivity values of truly representative samples could
logically be expected to be significantly higher. Additionally, the value re-
ported for Munich could not be associated with a specific mode of fuel-firing.
It can be assumed, however, that combined-firing, the normal operating-mode
of this unit, was probably being practiced when the fly ash was produced.
These resistivity values determined for Munich Block II and DUsseldorf are
in an excellent region for the cost-effective application of electrostatic pre-
cipitation.
2.
Gaseous Emissions
Compared to the situation in this country, there is less
reason for German national concern over control of sulfur-oxides pollution.
European coal is notably low in sulfur (less than 10/0). Fuel-oil burned in
Europe is also low in sulfur for the most part. Based on the limited data
available, derivations of sulfur-balances were made. This subject is dis-
cus sed in the main volume of the report.
B - 144
-------
G.
EUROPEAN FIELD TRIp.
1.
Scope of Activities
Observations were made and discussions held during a July
1969 survey of selected refuse disposal facilities in Germany, France, and
England by project personnel. No attempt was made to view each of the major'
European refuse operations, in that such general surveys have been reported
previously and adequate descriptive literature is available on many of the faci-
lities. What was intended was an examination of representative steam genera-
ting incinerators and refuse-processing equipment, along with interviews of
key personnel experienced in their operating, such that specific details on the
cataloging of design system candidates could be thoroughly considered. In ad-
dition, it has become apparent that personal expediting of approval for the
release of several of the requested acceptance test reports of the Technis cher
tJberwachungs - Verein (TtJV) was required.
As a result of the trip, all necessary TtJV approvals were
obtained and groundwork was laid for obtaining additional reports of other units
or for potential additional testing of units in the future. In the TtJV documents
obtained, the survey team had access to steam generator and electrostatic pre-
cipitator reports from five different units, rather than .on two combined-firing
units as had originaqy been planned.
Most of the information obtained has already been documented
in the present appendix or in other volumes of the report. Information was also
obtained, however, on refuse-firing plants other than the five German plants
just described. Comments on these additional facilities are therefore presented
in the next section. Table 19 lists the itinerary followed, the facilities visited,
. and the key personnel contacted.
2.
Other Refuse-Fired Plants Visited
a.
Essen-Karnap Plant
The prime purpose in visiting this plant was to inspect
the Lindemann shear and also a refuse-burning travelling grate (for comparison
with agitating grates). This plant was originally designed for firing pulverized-
coal and modified to burn, in addition, sewage sludge and refuse. Perhaps the
most interesting aspects of this plant are that it is a total-waste facility and
that it is one of the few plants built and operated by a private utility.
In this area all sewage is delivered to the Emse river
(parallel to the Ruhr river), from which open system it is later withdrawn for
treatment. Purified water is finally released to the Ruhr river. The classi-
fication sludge is brought to the plant on a long conveyor belt. An interesting
feature of the continuous belt is that it is twisted at each end so that the belt
rollers located below the belt are always in contact with the unused side of the
belt.
I
B-145
-------
Date,
1969
14 July
15 July
16 July
17 July
18 July
City
DUs s eldorf
Essen
Be r lin
Munich
Stuttgart
TABLE B-21
EUROPEAN FIELD- TRIP ITINERARY
Facility Visited
Vereinigte Kesselwerke AG
(VKW)
Rheinisch- Westf~lisches
Elektrizet~tswerk AG
(RWE)~ Essen-Karnap
Power Plant
Technischer tTberwachungs-
Verein Essen e. V. (TtiV)
VKW
Deutsche Babcock
Zentralstelle fUr Abfallbe-
seitigung des Bundesgesund-
heitsamtes (ZfA)
Berlin-Ruhleben Refuse-
Incineration Plant
ElektrizitIitswerk Mtlnchen
Munich South Plant
Josef Martin Feuerungsbau
GmbH
TtiV Bayern
German Consultant>:<
Technische Werke der
Stuttgart, Stuttgart-
MUnster Plant
VKW
>''
-------
Date,
1969
2 1 J u1 Y
22 July
23 July
24 July
25 July
28 July
29 July
3 0 J ul Y
City
Mannheim
Heidelberg
Frankfurt
Wiesbaden
Bad Godes-
berg
Duisberg
Paris
London
Surbiton,
Surrey
Chertsey,
Surrey
Old W oking,
Surrey
Epsom,
Surrey
TABLE B-21 - Continued
Facility Visited
Friesenheimer Island Plant
Composting Pilot Plant
Battelle lnstitut, e.. V.
Refuse Burning Plant
Landfill Station
U. S. Consulate
Composting Plant
VKW
Societe Foster Wheeler
Francaise
Traitment lndustriel des
R~sidus Urbains (TIRU)
Is sy-Ies -Moulineaux Plant
Ivry Plant
Foster Wheeler John Brown
Boilers, Ltd.
Tollemache Composting
Systems, Ltd.
Chertsey Urban District
Council - Landfill Plant
Woking Urban District
Council-Pulverizing Plant
Epsom District Council-
Pulverizing Plant
B-147
Personnel Contacted
lng. Grad. H. M. Hillsheimer
Oberbaurat. Hortsmann
Dip!. -lng. R. Rasch
Dr. F. Fink
lng. H. Thode
Dip!. -lng. H. Baumann
Direktor Steeg
Mr. N. L. Pazdral
Stadtbaudir. B. Frechen
Obering. K. Nuber
Mr. M. de Trincaud
Mr. B. J. Loygue
Mr. J. DefJche
lng. M. Tourret
lng. M. Tourret
Mr. Fourment
Mr. R. M. V. Beith
Mr. R. A. C. Bromwich
Dr. D. H. G. Tollemache
Mr. G. F. Robinson
Mr. W. S. Moncrieff
Mr. H. Bliczek
Mr. Hall
Mr. Brownjohn
-------
Essentially three types of refuse are delivered to the
plant. Municipal refuse is brought in by regular municipal trucks. Bulky
refuse is also delivered, usually by private vehicles, and is process.ed by a
Lindemann Shear. Industrial chemical refuse is accepted in a special pit or
in liquid-storage tanks. Reduced bulky-refuse is discharged to the same pit
where municipal refuse is dumped. There are doors at each truck stall
which open just far enough for the truck to discharge. An inclined apron is
provided so that the refuse crane cannot pos sibly hit a truck or door. The
pit, which is some distance from the refuse-burning facility, is designed to
be under negative pressure, but the odor near the pit-building is quite
noticeable.
A feature of this plant is that the raw refuse is sent
to a magnetic separation-step prior to delivery to the furnace. The recovered
metals are collected, baled, and removed daily. The metal is used in a foun-
dry producing cast iron; the small amount of tin present in this scrap is ap-
parently considered acceptable for this iron. This certainly does not apply
in the case of steel production. It was pointed out that metal baled after com-
bustion contains a great deal of ash which has to be removed before using the
metal in a melt. For this reason, the scrap commanded a price of $lO/ton,
a 50% premium over burned scrap.
From the metal separation step, the refuse is de-
livered by conveyor belt to the boiler house, where there are ten steam-
generators delivering steam to five steam-turbines. Five of the steam
generators have been modified to burn refuse. The other five are fired on
sludge. Boiler 3 was modified in 1961, boilers 1 and 2 in 1969, and boilers
6 and 7 in 1964; total capital costs for the refus e-handling modifications
amounted to $6.2 million. Both the clarification-sludge and the refuse are
brought to the respective furnaces by conveyor belt; 2000 tons of refuse and
a like quantity of sludge are handled daily.
Each of the five refuse-furnaces is completely re-
fractory-enclosed, with no heat-absorbing surface. The flue gas of the
combusted refuse is vented to the water-cooled boiler at a point below the
tangential coal burners. Average heating value of the refuse is 2160 Btu/lb
(LHV); the highest noted was 2880 Btu/lb (LHV). It was confirmed that this
plant had never experienced any corrosion of tube surfaces in any of the units.
The only tube wastage attributable to refuse-firing resulted when occasionally
the refractory furnace was overloaded and the flame impinged on the water
walls of the steam generator.
Recovery of ash, both bottom residue and fly, ash,
is well handled. Gern~an regulations do not permit the use of fly ash for
making concrete, while Dutch specifications are not restrictive. Almost
all of the fly ash collected (1000 tpd) is sold for $0.37 /ton to Dutch distri-
butors, who haul it to Holland in their own trucks, where they receive
$1. 87 /ton from ultimate users.
B - 148
-------
With regard to a private utility (RWE - see Table
B-2l) handling refuse, it was pointed out that the operation was somewhat
forced upon them by the local municipality. The R WE agreed to handle
refuse in exchange for providing power to some sections of the area pre-
viously served by municipal power. It was explained that the RWE is
compensated for handling the refuse and sludge in a rather complicated
manner, which assures a normal return on the investment.
When queried about the future possibilities of private
utilities, such as RWE, building refuse-burning plants, RWE management
was quite sure that none would be built. The reasoning was quite straight-
forward. It was claimed that a coal-fired steam generator can be operated
with essentially one man, while a combined-fired unit requires fourteen men.
It was also pointed out that even if better systems could be developed, the
private utilities would probably not be very interested. It is more advan-
tageous from both a production and economic viewpoint to build large power
plants near the source of fuel and transmit power to the load centers. Ac-
cording to RWE the only reason why Germany has been in the forefront of
refuse burning is because most large cities have municipally-owned and
-operated power plants. However, the private utilities are desirous of
providing the power presently generated by the municipalities. A gradual
take-over of municipal power systems by the private utilities is foreseeable.
This would then suggest that private utilities would be required to operate
existing refuse-burning plants.
A large combined-firing plant similar to that at
Essen-Karnap was planned for the Cologne area and described in 1965 in
a special issue, devoted to refuse-incineration, of Brennstoff- W~rme-Kraft.
The fact that plans for this plant never materialized is perhaps an indication
of this trend.
b.
Berlin-Ruhleben Plant
This plant is rather unique because it is actually
three plants in one. It is a refuse-incineration plant, a clinker-processing
plant, and a clinker-sintering plant. The completed structures will even-
tually include six boilers. To date, four are operating and two are in the
construction stage. Steam is delivered to the existing Reuter power plant
across the river. Superheated steam is delivered at or above 9050F (940
psig); the steam-flow chart indicated considerable flow-variation. The
arrangements with the power plant involve two rates of payment. A lower
payment is given when the steam temperature falls below 9050F. When
this occurs the steam from the refuse-burning plant is diverted from the
high-pres sure-turbine to the intermediate-pressure turbine. It is claimed
that this is automatically controlled. .
B-l49
-------
I
The plant has suffered some corrosion in the fur-
nace, due to localized reducing-atmospheres. An increase in the excess
air used has virtually eliminated this corrosion. Along the roller-grates
in this furnace are waterwall tubes which eventually become part of the
side wall. These tubes have also suffered some wastage. This type of
construction is also used in Stuttgart and Mannheim but more for the
purpose of abrasion protection than for heat pickup. While some wastage
has been noted at Stuttgart, none was reported at Mannheim. Some tubes
in the Berlin-Ruhleben plant have failed because of longitudinal cracks.
In several places, ash had collected behind the tubes, which thus were
being pushed out into the furnace. These units do not have welded walls.
There was heavy ash-accumulation in the superheater, although no plug-
ging had yet occurred. It was claimed that the refuse in Berlin contains
more ash than in most other German cities.
A novel refuse-feeding arrangement, consisting of
a continuous, tank-track conveyor, is used between the chute and the fur-
nace grate. Most European plants use table-type feeders. Generally,
thes e feeders are not us ed in the U. S.
The sintering plant had not been as successful as
expected. When product from this plant was mixed with concrete, cracks
developed in the cured material. This had not been a problem during pilot
plant evaluations. The cause is believed to be elemental aluminum. Ap-
parently aluminum-foil has been marketed only recently in Berlin. It is
claimed that the aluminum passes through the furnace unoxidized and
failure of the concrete is caused by the reaction of the free metal with the
alkaline cement slurry. After working with Battelle on this problem, it is
now believed that by washing the residue in lime solution the aluminum can
be dissolved. The sintering plant was not operating when visited, although
charts in the control room indicated that the plant is operated at least
several days each month.
c.
Munich-South Plant
This plant was indeed the cleanest and most impres-
sive plant seen on the trip. The combined refuse/natural gas facility is Unit
No.6. The other units are coal-fired boilers. Unit No.5 has been ordered
and will be a duplicate of No.6, although construction had not yet begun. In
the control room the steam-flow trace was seen to be very smooth, exhibiting
much less variation than did the units in the Munich-North plants. The grate
used in this unit was a Martin design, the refuse-furnace was by VKW, and
the natural-gas -fired steam generator was constructed by Deutsche Babcock.
This unit also has a capability for future coal-firing, although the bunkers
and mills have not yet been installed in the space provided.
B-l50
-------
The flue gas leaving the refuse-fired economizer is
too hot for introduction into the electrostatic precipitator. It is therefore
mixed with the cooler flue gas produced by the natural- gas -fired boiler. If
only refuse is burned, the flue gas will have to be cooled by water sprays.
Only refuse collected by municipal trucks is brought
to this plant. Bulky refuse is handled by special trucks equipped with built-
in shredders. The importance of having at least that degree of control over
refuse size was stressed. The residue is removed by conveyor belt and is
first taken to a magnetic separator. Baled scrap is loaded into railroad cars
and residue is taken to landfill by truck. Double doors are employed at the
refuse pit, with interlocks provided to prevent both doors from opening simul-
taneously. Air is withdrawn from the top of the pit. As in Berlin, one could
not smell any refuse unles s standing at the edge of the pit. An interesting
point on the architecture is that there are several floors of offices located
above the unloading dock. The crane operators were located in a pulpit at
the top of the pit, similar to the Berlin operation. The pulpit was located at
an elevation even with the chute. However, unlike the Munich-North plants
and the Essen-Karnap plant, it is physically possible for the crane to hit an
unloading truck unless a stop on the bridge of the crane is provided.
d.
Mannheim Plant
The Mannheim plant is located on Friesenheimer
Island in the Rhine river; there are some industrial complexes on the islands
as well as a landfill. When the 4-year old refus e- burning plant is not operable,
refuse trucks are diverted to the landfill; steam demands are fulfilled by ope-
rating standby, oil-fired boilers. At the time the installation was planned,
the various grates available were studied but none of them was considered
particularly well suited for refuse-burning. The choice of a traveling-grate
was based simply on the fact that it was the cheapest machine available. It
was found to be advantageous, however, to use several grates in order to
achieve some agitation by tumbling. When the plant was first started some
corrosion was noted, but it appears to have subsided somewhat. The con-
vection sections of the steam generator, several of which have staggered-
tube arrangements, are similar to the Stuttgart unit; it would therefore
seem that erosion may have been as much the cause of tube-wastage as
corrosion. .
Thi's unit is similar to the units at Berlin and Stutt-
gart, in the use of several rows of waterwall tubes parallel to the grate for
abrasion protection. At Mannheim, however, the feedwater is first sent
through these tubes before flowing to the economizer. At Berlin and Stutt-
gart, the abrasion-protection tubes are part of the boiling section. It was
claimed that no failure of these abrasion-protection tubes had occurred at
Mannheim. It would appear likely that tube-wastage of this section would
be dependent upon metal temperature.
B-15l
-------
On the day of the visit, one unit was out of service for
a scheduled outage. In this unit, part of the superheater is built in the upper
quarter of the side-wall. This superheater surface was being removed and
replaced by waterwalls. The other unit was down on an uns cheduled outage
for repair of the grate.
As at the other plants visited, the Mannheim Plant
was equipped with electrostatic precipitators. As in Stuttgart, a Hazemag
shredder was used to reduce bulky waste.
e.
Frankfurt am Main Plant
Here, plant management admitted that some corrosion
problems had been experienced but not of an unmanagable degree. The steam
produced here is for district-heating and hot water supply (through heat ex-
changers) in an adjacent apartment-house complex. The steam produced by
refuse-burning is an auxiliary source to that from conventional, oil-fired
boilers. One of the unique features of the refuse-burning units is that the
refuse from the crane is dumped on a vibrating trough, which in turn dis-
charges to a vertical chute. While an interesting feature, it is doubtful that
it is a necessary one. No other plants are known to have such an arrange-
ment, and all appear to work well without it. As in other plants, the pit and
building have been built with a view to future capacity requirements. With
extra pit-capacity, the operators try to stagger refuse deliveries on a weekly
basis, so that they maintain some week-old refuse. It is claimed that more
uniform burning is achieved by mixing aged and fresh refuse. The furnace
volume was found to be extremely generous, and no overfire air was used.
Judging from the fact that the excess air was nearly 100% and the flames
produced were somewhat lazy and spotty, the grate surface-area was probably
oversized. The residue from this plant revealed much unburned material,
including partially-burned paper. As in Munich, trucks with built-in shredders
were employed, in lieu of stationary shredding equipment at the plant.
The most persistent maintenance problem mentioned
involved the crane cables which had to be replaced every few weeks. The
cranes in this plant were equipped with an automatic control system, so that
once a bucket was loaded the charge could be automatically taken and dis-
charged at a predetermined chute. However, in the automatic-mode the
crane could move in only one direction at a time. This resulted in an un-
acceptably slow feeding-rate. Manual operation, in which simultaneous
tridirectional control is routinely achievable, had to be adopted therefore.
f.
Issy-les-Moulineaux Plant
This plant is located near the Seine, just outside of
Southwest Paris. It contains four refuse-fired, natural-circulation boilers,
which utilize auxiliary fuel (oil) only on start-up. The rated plant-capacity
is 60 tph while operating at steam conditions of 7700F and 925 psig.
B-152
-------
. Samples of refuse. amounting to approximately 5
tons. are taken 10 days of the year. It is claimed that samples taken during
the summer indicate heating values higher than the steam generator calcu-
lated heating value. During the winter. analyzed samples are lower than
calculated by records. The furnace exit temperature is maintained below
1000oF. The average LHV is 3600 Btu/lb. The minimum LHV is 1600
Btu/lb. The grate metal temperature is between 300 and 400oF. In this
plant. as in some other plants. a siftings -hopper is located under the table
feeder. Uncompressed. recovered metals are sold for $18/ton.
In-line tube spacings were used throughout the con-
vection sections. The air is heated in a steam-coil air heater. The first
corrosion noted occurred after 5.000 hours. while superheater trouble oc-
curred after 14.000 hours.
Refuse is collected by mun~cipalit~es or private con-
tractors. The plant receives money from the municipalities at the end of the
year and the amount is dependent, in part. on the plant operation. The budget
amount set by the TIRU is $8. 10/ton.
g.
Ivry Plant
This plant is also located near the Seine. but outside
of Paris to the southeast. The plant had just started up one steam generator
and the other was scheduled for completion by October 1969. The operating
unit was still undergoing some tests and it was not possible to observe the
steam-flow traces. The designed operating conditions are 8750F and 1400.
psig, using natural-circulation boilers. Like the Issy plant. a reciprocating
grate is employed and refuse constitutes the sole fuel used. except on start-up.
Upon completion. Ivry will be the world's largest
refuse-fired steam generation facility. with the two furnaces being able to
handle 2400 tons/day. The completed plant cost will be $30 million.
As elsewhere. the pit operators are located in a
pulpit. However. at Ivry the pulpit is located at a point lower than the chute.
The operator has therefore been provided with a closed~circuit television
and constantly has a view of the chute on the screen.
B-153
-------
VI.
B-l.
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Plant for Maximum Steam Production, II Proc. of 1966 National
Incinerator Con£., ASME.
IIEast Hamilton Solid Waste Reduction Unit, Preliminary
Engineering Report, II G. L. Sutin and Associates, Ltd.,
July 1968.
Sutin, G. L., "Solid Waste Reduction Unit Promises to be
a Better Mousetrap," Public Works, 100, 98-105, Feb. 1969.
Cohan, L. J., and Fernandes, J. H., "Potential Energy
Conversion Aspects of Refuse, II ASME Paper No. 67- WAf
PID- 6.
Regan, J. W., "Generating Steam from Prepared Refuse, II
Proc. of the 1970 National Incinerator Con£., ASME.
Regan, J. W., Mullen, J. F., and Nickerson, R. D., "SUs-
pension Firing of Solid Waste Fuels, II Proc. Amer. Power
Con£. , 1.!; 599-608, April 1969.
Mihm, V., liThe FLK Slagging Incinerator, a New Design
Concept, II Paper presented to the Design Committee of ASME
Incinerator Div., N. Y., March 1969.
Triebel, W., and Nowak, F., "Production of Fused Phosphate
Fertilizer by Means of Hygienic Preparation and Dest'ruction
of Municipal Refuse, II Forschungsberichte des Landes Nordr-
hein- Westfalen, Rept. No. 858, 1960.
Kaiser, E. R., "Evaluation of the Melt-Zit High Temperature
Incinerator, Oper.ation Test Report, Aug. 1968, II Report to
the City of Brocton, Mass., on USPHS Grant No. D01-UI-
00076, 1969.
Plumley, A. L., Lewis, E. C., and Tallent, R. G., IIEx-
ternal Corrosion of Water Wall Tubes in Kraft Recovery
Furnaces, II TAPPI, 49 (1), 72A-81A, Jan. 1966.
Trostel, L. J., Jr., "Slagging of Incinerator Refractories, "
Presented at ASME Incinerator Div. Meeting, New York,
9 Nov. 1969.
Joyce, J. S. (Siemens America, Inc.) Private Communication
to Project Staff Member, 7 Jan. 1970.
B-159
-------
B-79.
B-80.
B-81.
B-82.
B-83.
B-84.
B-85.
B-86.
B-87.
B-88.
B-89.
B-90.
B-91.
"Criteria for the Application of Dust Collectors to Coal
Fired Boilers, " Results of IGCI-ABMA Joint Technical
Committee Survey, Proc. Amer. Power Conf., 1967.
Schmitz, F. W. D Moore, W. W., and Knecht, H., "Per-
formance Results on Particulate Removal Upstream of an
Airheater when Burning Fuel Oil, " American Power Con£.,
Chicago, April 1966.
Smith, W. D. IJ "Atmospheric Emis sions from Fuel Oil
Combustion, An Inventory Guide, II Public Health Servo
Pub. 999-AP-2, Nov. 1962.
Lynch, C. E., "Experience with the Operation of Electro-
static Precipitators on Oil-fired Boilers, " 13th Annual
New England Section APCA Meeting, 1969.
Burdock, J. L., "Fly Ash Collection from Oil-fired Boilers,
10th Annual New England Section APCA Meeting, 1966.
White, H. J., "Industrial Electrostatic Precipitation, "
Addison Wesely Publishing Co., Reading, Mass., 1963.
"Determination of the Characteristics of Boiler Flue Gas
Desulfurization Additives and Reaction Products, " Babcock
and Wilcox Co., Final Report on HEW Contract No. PH 86-
67-127, 27 March 1970.
"Full Scale Limestone Injection Tests at Shawnee Unit 10,
Test Program, " Tennessee Valley Authority, Report on
NAPCA Project No. 2438, May 1969.
Cahill, W. J., Jr., "Control of Particulate Emissions on
Electric Utilities Boilers, " Proc. MECAR Symp. New De-
velopments in Air Pollution Control, Oct. 1967.
Cuffe, S. T. D et aI, "Air Pollutant Emissions from Coal
Fired Power Plants, Report No.1, "JAPCA, 14, 352-62,
Sept. 1964. -
Idem., Report No.2, ibid., 15, 59-64, Feb. 1965.
Bartok, W., et aI, 'ISystems Study of Nitrogen Oxide Control
Methods for Stationary Sources, " Esso Res. & Eng. Co.
Final Report on NAPCA Contract PH 22-68-55, 20 Nov. 1969.
"Air Pollution Engineering Manual, " USPHS Publication
999-AP-40, 1967.
B-160
-------
B-92.
B-93.
B-94.
B-95.
B-96.
B-97.
B-98.
B-99.
B-1 00.
B-IOI.
B-I02.
B-1 03.
B-1 04.
Smith, W .S., and Gruber, C. W., "Atmospheric Emissions
from Coal Combustion, An Inventory Guide, " Public Health
Service Publication 999-AP-24, April 1966.
Gurinov, B. P., "Effect of the Method of Combustion and
Type of Fuel on the Content of 3, 4-Benzpyrene in Smoke
Gases," Gigiena i Sanitaria, Moscow, Q (12), 6-9 (1956).
Semrau, K., "Correlation of Dust Scrubber Efficiency, ';'
JAPCA, .!.Q., 200-205, June 1960.
McLaughlin, J. F., and Jonakin, J'~, "S02 Trapped in Full
Scale System," Electrical World, 13 November 1967.
Deutsch, W., I'Motion and Charge of Electrostatic Carriers
in a Cylindrical Condenser, 'I Ann. Physik, 2, 335-44 (1922).
"Review of Bureau of Mines Coal Program, 1967, II U.S.
Dept. of the Interior, Bureau of Mines, Information Cir-
cular 8385, June 1968.
Dennis, R., and Bernstein, R. H., "Engineering Study of Re-
moval of Sulfur Oxides from Flue Gases, " GCA Corp. Re-
port, prepared for API Committee for Air and Water
Conservation, Aug. 1968.
"An Interim Report on Sulfur Oxides Pollution Abatement
R&D, " Committee on Government Operations, Federal Air
Pollution Research and Development, Second House Report
No. 91-79.
Sensebaugh, J. D., and Jeffries, G. C., "Effect of Operating
Variables on the Stack Emission from a Modern Power Station
Boiler, " ASME Paper 59-A-308.
McGlauchlin, L. D., "Long Range Technical Planning, "
Harvard Bus. Rev., 46 (4), 54-64 (1968).
"Air Quality Criteria for Sulfur Oxides, II U.S. Department
of Health, Education and Welfare Public Health Service,
NAPCA, Publication No. AP-50, Jan. 1969.
"Air Quality Criteria for Particulate Matter, II U.S. Depart-
ment of Health, Education and Welfare Public Health Service,
NAPCA, Publication No. AP-49, Jan. 1969.
"Report of Dust Collector Performance Tests in March 1965;
Boiler III Block I in the North Power Plant of the Munich City
Works," TtTV Bayern e. V., Munich, 28 June 1965.
B-161
-------
B-1 05.
B-1 06.
B-I07.
B-I08.
B-I09.
B-II0.
B-lll.
B-112.
B-1l3.
B-1l4.
B-1l5.
B-1l6.
"Report of Dust Collector Performance Tests in Nov. 1967;
Block II in the North Power Plant of the Munich City Works, "
TtJV Bayern e. V., Munich, 17 May 1968.
"Report of Dust Collector Performance Tests in July 1966;
Refuse Boilers 28 and 29 of the Steam Power Plant in Stutt-
gart - Mtlnster der TWS, " TtJV Stuttgart e. V., Stuttgart,
Aug. 1966.
"Report of Dust Collector Performance Tests in March 1967;
DUs seldorf City Works, trash-incinerator plant Flingerbroich, II
TtJV Rheinland e. V., Report No. 8/146/66, 25 July 1967.
Nowak, F., IIOperating Experience at the Refuse Burning
Plant at Stuttgart, II Brennstoff-W~rme-Kraft, 19 (2), 71-76
(1967). -
Walker, A. B., I'Emission Characteristics from Industrial
Boilers, "Ind. Coal ConI., LaFayette, Ind., 12 Oct. 1966.
Stenburg, R. 1., et aI, "Field Evaluation of Combustion Air
Effects on Atmospheric Emissions from Municipal Incine-
rators, II JAPCA, g (2), 83-9, Feb. 1962.
Neissen, W., et aI, A. D. Little Co. Final Report on NAPCA
Contract CPA 22-69-21, March 1970.
Walker, A. B., and Schmitz, F. W., IICharacteristics of
Emissions from Large, Mechanically-Stoked Municipal In-
cinerators, II Proc. of the 1966 National Incinerator Con-
ference, ASME.
Andritzky, M., "Design and Maintenance of the Five Gas
Dust Removal Installations at the Munich Power Plant
INord II," Brennstoff-WMrme-Kraft, 19 (9), 436-39,
Sept. 1967. -
Bump, R. L., "Conditioning Refractory Furnace Gases Iqr
Electrostatic Precipitator Application, " Proceedings of the
1968 National Incinerator Conference, ASME.
Liesang, D., "The Effect of Gas Temperature upon the Per-
formance and Design of Electrostatic Precipitators, II Staub-
Reinhaltung der Luft, 28 (10), 403-5, Oct. 1968.
Coutallier, T., and Richard, C., "Improvement of Electro-
static Precipitators by S03 Injection, " Pollution Atmos-
pherique, .2. (3), 9-15, Jan. -Mar. 1967.
B-162
-------
B-117.
B-118.
B-119.
Stabenbow; G., "European Practice in Refuse Burning. II
Proceedings of the 1964 National Incinerator Conference,
ASME.
Eishold, H. G., "A Measuring Device for Determining the
Specific Electrical Resistance of Dust, " Staub-Reinhaltung
der Luft, 26 (1), 14-21 (1966).
Maikranz, F., "Incineration of Refuse arid Heat Recovery
Experience with Mixed Firing, " Mitteilung VGB, 48 (2),
111-118, April 1968. .
B-120. . Bump, R. L., Wheelabrator Corp., Private communication.
~
,:"...'
B-163
-------
APPENDIX C
COST MODEL
-------
1.
INTRODUCTION
The following sections discus s in detail the data and equations that were
developed and incorporated into the cost model computer program. Three
basic models have been developed: (1) combined firing plant, (2) conventional
firing plant, and (3) a transportation model. Each model has been derived as
a series of equations describing the cost of equipment, fuel, labor, and other
cost variables as a function of the major design parameters (waste load, elec-
trical generating capacity, waste fraction). In addition to the equation form,
each maj or cost element is also portrayed in graphical form to facilitate ana-
lysis of the model. Unless otherwise referenced, cost data presented in this
appendix is based on information provided by Foster Wheeler, Research-
Cottrell, and A. E. Gosselin, Consultant to Aerojet-General. The effective
base date for all costs is July 1969.
II.
COMBINED FIRING PLANT MODEL
The results of a series of conceptual design studies have been incor-
porated into a cost model that represents an estimate of the cost of each
major piece of equipment and operating expense in the combined firing plant.
The model generates costs from the receiving area through the disposal of
the incinerator residue. The costs are divided into capital costs, annual
capital costs, operation and maintenance costs, and residue disposal costs.
A.
CAPITAL COSTS
The total capital costs represent the investment in equipment
and/or facilities that are required by a waste-fossil fuel power generating
plant. A summary of the cost elements and estimated equipment life is
given in Table C-l. Where applicable, the cost elements have been grouped
according to the FPC codes. Elements not fitting under a particular code
are listed separately. Specifics concerning each element are presented in
the following paragraphs.
1.
Land and Land Rights
The unit cost of land is treated parametrically. The land
area required is a function of power output and the quantity of waste handled.
It was estimated that approximately 37 acres plus 6.5 acres per 100 MW
would be required for the power plant and that an additional 2 acres would
be required for each 1000 tons per day of waste. This leads to the follow-
ing equation:
Where:
CLC = \0.065 PT + 37 + :-;; ) CA
CLC = capital cost of land, dollars
C A = unit cost of land, dollars per acre
W = waste load, tons per day
w
PT
= total plant output power, megawatts
C-l
-------
r'PC
CODE
310
311
312
314
315
316
TABLE C-l
ESTIMATED EQUIPMENT LIFE
DESCRIP TION
ES TIMA TED
LIFE, YEARS
Land and Land Right
Infini t e
Structure s and Improvements
20
Boiler Plant Equipment
Steam Generator
20
Water Treatment Equipment
25
Pump s
10
Piping
20
Coal Handling Equipment
25
Residue Handling Equipment
20
Stacks
25
Turbine - Generator Equipment
25
Acces sory Electrical Equipment
15
Miscellaneous Power Plant Equipment
Miscellaneous Equipment
25
Power Plant Cranes
15
Air Pollution Control Equipment
20
Waste Handling Equipment
Receiving and Storage Equipment
25
Scales
15
Shredders
10
C-2
-------
Figure C-l shows land costs as a function of power and processed waste load
with the unit cost of land set at $10,000 per acre.
2.
Structures and Improvements
. The capital cost of structures and improvements includes
building substructure and superstructure, piling, structural steel, painting,
landscaping, roads, railroad siding fencing, sewers, and site preparation.
Since a plant capable of handling solid waste may require several steam
generators, the structure cost is obtained by solving the basic equation at
a power level equivalent to the individual steam generator and then multi-
plying this by the number of steam generators to the 0.9 power. The 0.9
power is to take into account that even though the structures are larger, the
appurtenances would not increase directly with the number of steam genera-
tors. The cost equation then is:
CSF =
4 [ PT
5.06 x 10 (Ns)..
1, J
f755
(N )0.9
s . .
1,)
where:
CSF =
(N )
s . .
1, J
cost of structures and improvements
= number of steam generators at power level i
and waste fraction j
Figure C-2 shows structure costs as a function of power and the number of
steam generators used. The number of steam generators required depends
on the design as shown in Tables C.,.2 through C-9.
3.
Boiler Plant Equipment
The capital cos t of boiler plant equipment includes, in
addition to the steam generator, the following auxilia ry items: boiler water
treatment, pumps, piping, coal and residue handling equipment, and stacks.
Auxiliary boiler equipment is dis cus sed separately in the next section.
Steam generator costs were estimated for ten different
design configurations designated Cases 1 through 10; these have been de-
scribed in Section Ill, B of Volume 1. The design criteria for each of these
cases are shown in Tables C-2 through C:-9. The items included in the
steam generator cost estimates are shown in Table C-IO. As shown in
the tables, costs were developed at several power levels and refuse frac-
tions for cases 1, 2, 3, 6, 7, 8, and 9. Due to t~e nature of cases 4, 5,
and 10, only one refuse fraction (fw) was considered. In order to use the
data presented in these tables in the computer p:r;ogram, equations were
fit to each set of cost data.
C-3
-------
()
I
*'"
~
~
Q
-
Q' 0.&
z
<
....
u.
o
~
U)
o
(J
.... 0.4
<
~
~
(J
1.0
0.8
0.2
fw = FRACTIONAL HEAT INPUT FROM WASTE
o
o
1000
2000
3000 4000 5000
PROCESSED WASTE LOAD, TPD
6000
7000
8000
FIGURE C-1. CAPITAL COST ( F LAND
-------
8
. NUM.BER OF
~ STEAM GENERATORS
(&)0 6
...
vi
w
IE:
;:)
t;
;:)
IE:
t; 4
u.
0
t;
0
u
-'
4(
...
~ 2
u
o
o
100
200 300
NAMEPLATE RATING. MW
400
500
. F.'GURE C-2. CAPITAL COST OF STRUCTURES
C-5
-------
TABLE C-2 - CASE 1
S TEAM GENERA TOR DESIGN AND COS T INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 40 20 40 60 40 20 40 60 40
Steam Pressure, psig 1250 1800 1250 850 1250 1800 1250 1250 1250
Number of Steam Generators 2 2 3 5 5 3 6 9 7
Number of Turbines 2 1 3 5 4 2 5 5 6
Steam Generator Cost, 106 $ 13.0 15.8 2.4.2 37.5 34.5 26.2 42.6 59.6 51. 0
()
I
0'
-------
,.
TABLE C-3 - CASES 2 AND 8
S TEAM GENERA TOR DESIGN AND COS T INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 40 20 40 60 40 20 40 60 40
Steam Pressure, psig 1250 1800 1250 850 1250 1800 1250 1250 1250
Number of Steam Generators 2 2 3 5 5 3 6 9 7
Number of Turbines 2 1 3 5 4 2 5 5 6
Steam Generator Cost, 106 $ 10.4 13. 3 17.4 24.2 27.6 23.0 34.2 44.7 41. 1
o
I
--.]
-------
TABLE C-4 - CASE 3
S TEAM GENERA TOR DESIGN AND COS T INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 10 16.6 10.1 16.6 10.4 20.2 24.9 9.9 20.4 24.9 10.6 20.3 24.9
Steam Pressure, psig 1800 1800 1800 1800 2400 2400 2400 2400 2400 ~400 2400 2400 2400
Number of Steam Generators 1 1 1 1 1 2 3 2 3 3 2 4 4
(Refuse)
Number of Turbines 1 1 1 1 1 1 1 1 1 1 1 1 1
Steam Generator Cost, 106 $ 7.6 8.2 12.0 13.4 15.9 20.6 21. 0 20.5 23.6 25.3 24.2 29.5 31. 6
o
I
00
-------
TABLE C-5 - CASE 4
STEAM GENERA TOR DESIGN AND COST INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate. % 63.5 63.5 58.3 58.3 58.3
Steam Pressure, psig 1800. 1800 2400 2400 2400
Number of Steam Generators (Refuse) 3 5 6 7 9
Number of Turbines 1 1 1 1 1
Steam Generator Cost, 106 $ 14.4 22.9 28.5 34.9 42.7
()
I
-.D
-------
TABLE C-6 - CASE 5
S TEAM GENERA TOR DESIGN AND COS T INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 75.5 75.5 71. 3 81. 3 71. 3
Steam Pressure, psig 1800 1800 2400 2400 2400
Number of Steam Generators {Refuse} 3 5 7 9 11
Number of Turbines 1 1 1 1 1
Steam Generator Cost, 106 $ 15. 1 22.8 28.9 37.0 44.7
()
I
>-'
0
-------
TABLE C-7 - CASES 6 AND 7
S TEAM GENERA TOR DESIGN AND ca; T INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 40 20 40 60 40 20 40 60 40
Steam Pressure, psig 1250 1800 1250 850 1250 1800 1250 1250 1250
Number of Steam Generators 2 2 3 5 5 3 6 9 7
Number of Turbines 2 1 3 5 4 2 5 5 6
Steam Generator Cost, 106 $ 9.3 12.8 16.4 22.5 24.8 22.3 31. 6 42.0 34.2
()
I
,.....
,.....
-------
TABLE C-8 - CASE 9
STEAM GENERATOR DESIGN AND COST INFORMATION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 40 20 40 60 80 40 20 40 60 40
Steam Pressure, psig 1800 1800 1800 1250 1250 1800 1800 1800 1250 1800
Number of Steam Generators 1 1 2 3 4 2 2 3 5 4
Number of Turbines 1 1 1 3 3 2 2 2 5 3
Steam Generator Cost, 106 $ 7.6 11. 3 14.8 18. 1 21. 9 18. 8 22.6 25.8 32.3 33.0
()
I
......
N
-------
TABLE C-9 - CASE 10
S TEAM GENERA TOR DESIGN AND COS T INFORMA TION
Nameplate Rating, MW 100 200 300 400 500
Refuse Rate, % 58 58 54.5 54.5 54.5
Steam Pre s sure, ps ig 1800 1800 2400 2400 2400
Number of Steam Generators (Refuse) 1 2 3 3 4
Number of Turbines 1 1 1 1 1
Steam Generator Cost, 106 $ 10.2 15.9 . 22.3 27. 5 31. 7
()
I
......
LV
-------
TABLE C-lO
ITEMS INCLUDED IN STEAM GENERATOR COSTS
Boiler pres sure parts
Structural steel for boiler
Platforms and stairways
Fans and motor drives
Water cooled charging hopper
Feed gate
Stoker
Flues and ducts
Refractory insulation and lagging
Tiebacks and backstays
Soot blowe r s
Normal boiler valves and trim
Hydraulic system for stoker and feed gate
Supplementary oil or gas burners
Economizer
Instruments
Combustion control - pos itioning type
Siftings removal from precipitators and other hoppers
C-14
-------
CSG =
a.
Case 1 - Separate 'Furnaces, Blended Flue Gas
[ ( )N ]
2 3 PT 1 6
(14.3 + 33.3 fw- 16: 2 fv., + 65 fw) 200- 5 10
and
Nr
_1 (20.13 + 34. 14 f + 125. 75 f~ - 98. 54 f3)
= (0.301) xlog ,w N W
, 14. 3 + 33. 2 £ - 16. 2 f2 + 65 f3
, , w w w
CSG = capital cost of steam g,enerators, $
f = ratio of solid waste heat input to total heat input
w
whe re:
PT
=
nameplC\.te rating or total plant outputpoV(er, MW
b.
Case 2 - Combined Furnace
Due to the discontinuities in the cost surface, two
equations are necessary for this case.
" (CSG)H =
-,
and (NU)H =
(CSG\ =
and
(NU)
L
r, ' (p ')(NU)H ]
L(29.3 + 24.08 fw - 31. 25 f: + 54. 17 f~) 2~0 -20 106
, ,
, 1 (35.1 +24.58 f + 91.25 £2 - 83.3 f3 )
- w 'w w
(0.301) x log ,
" 29.3 + 24.08 f - 31. 25 f2 + 54. 17 f3
'W' ' w w.
[ (p )(NU) ]
(29.3 + 24.08 fw - 31. 25 f: - 4. 17 f~) 2~0 L -,20 106
= (NU)H / 1. 7
where:
(CSG)H = capital cost of steam generators for 200 ~ PT ::S 500
(CSG)L ' =
capital cost of steam generators for PT < 200
C-15
-------
c.
Case 3 - Separately Fired Economizer
CSG =
~ 2 ( P T + 50) Ill] 6
L(5.27 + 130 fw - 271 fw) 350 N 10
- 1 (1 7. 2 5 + 72. 1 f w - 5 8. 5 f~)
(0.196) x log
5. 27 + 130 f - 27 1 f2
w w
and
NIlI =
d.
Case 4 - Separate Fossil Fuel Superheater
(Saturated Steam from Refuse-Fired Boiler)
For this case, f can assume only one value for each
power level; consequently, cost is a fun~tion of power only.
(C SG) = 14.56 x 104 (PT + 50)0.898 and 250 S PT S 500
H
(CSG) = 66. 5 x 104 PT 0.688
L
and PT < 250
e.
Case 5 - Separate Fossil Fuel Superheater
(Partial Superheat from Refuse-Fired Boiler)
This case is similar to Case 4 in that there is only one
value of f for each power level.
w
(CSG)H = 22.4 x 104 PT 0.851 and 300 ~ PT ~ 500
(CSG) L = 98 x 104 PT 0.591
and PT <300
f.
Case 6 - Suspension Fired Steam Generator
and
NVI
(CSG)L 0 \(1.12 -.005 fw + .3lf~ exp [Nyr(PT - 200)]
(1. 14 + 1. 38 fw + 1. 14 f~)
= O. 005 x In 2
1.12 - .005 f +.31 f
w w
-I 1108
(CSG)H 0 1(1. 12 - .005 fw + . 31 f~ exp [~~: (PT - 200)]
- 1 \ 108
C-16
-------
-.-,\
where:
(CSG) =
H
capital cost of steam generators when PT ~ 450
(CSG) = capital cost of steam generators when PT <450
L
g.
Case 7 - Spreader Stoker
The steam generator cost for this case is the same
as for Case 6.
h.
Case 8 - Slagging Furnace
. The capital cost of steam generators for the slagging
furnace is the same as for Case 2.
i.
Case 9 - Combined-Fired Arch Furnace
A preliminary analysis of the cost data for this case
shoVl(ed that it would not be economically competitive with other cases. There-
fore, an equation form was not derived for this case.
j.
Case 10 - Refuse-Fired Arch Furnace and Separate
Coal-Fired Superheater
(CSG)H -3 0.689 and PT >250
= 442 x lOP T
(CSG)L 3 0.637 and PT S 250
= 545 x 10 PT
4.
Auxiliary Boiler Equipment
The basic capital costs for boiler feed water treatment
pumps, piping, coal and residue handling, and stacks, were also fit to
equation form. The costs of these equipments were adjusted for the number
of steam generators required, with the exception of piping costs which were
adjusted for the number of turbines required in each of the designs con-
sidered. Since the amount of furnace residue and stack gas are dependent
on the relative quantities of solid waste and fos sil fuel, the costs are ex-
pressed as functions of the waste and coal flow rates. The equations take
the following form and are illustrated in Figures C-3 through C-8.
C-17
-------
Cw
CpE =
Cp
Cco =
CR =
and A =
Cs =
where: Cw =
CpE =
Gp =
CGO =
GR =
A =
TlSGW =
TlSGF =
Wf =
W =
w
GS =
(N ). .=
s 1,J
(N -). .=
'1"1, J
=
2.21 x 103p
T
4( PT )0.73
1.11 x 10 .(N ). . (Ns)i,j
S 1, J
5.9 x l03( P T )1. 1 (NT)"
\(NT)' . 1, J
1, J
1. 8 x 10 [p (1 - w SGW
4 T 'lSGF(: - f:> + 'lSGW fw
3.66 x 104 (Nsf.) 0.858 (Ns)i J.
1, J '
-3 -3
1.18xl0 Wf+8.3xIO Ww
(934 Wf + 500 Ww) O. 151
)r74
=
capital cost of boiler water treatment equipment, $
(see Figure G-3)
capital cost of pumps, $ (see Figure G-4)
capital cost of piping, $ (see Figure G-5)
capital cost of coal handling equipment, $ (see Figure G-6)
capital cost of residue handling equipment, $ (see Figure G-7)
furnace residue, tph
boiler efficiency for refuse firing
boiler efficiency for coal firing
coal rate, tpd
solid waste rate, tpd
capital cost of stacks, $ (see Figure G-8)
number of steam' generators in the plant at power level i
and waste fraction j
number of turbines in the plant at power level i and waste
fraction j
G-18
-------
I-
I
1.0
*
CD
o
...
1-- 0.8
z
w
~
Q.
:;)
o
w
I-
~ 0.6
~
I-
<
w
a:
I-
a:
w
I-
<
~ 0.4
u..
o
I-
CI)
o
U
..J
<
I-
a: 0.2
<
u
o
o
200 300
NAMEPLATE RATING, MW
400
100
FIGURE C-3. CAPITAL COST OF WATER TREATMENT EQUIPMENT
C-19
500
-------
2.0
1.5
~o~s
fc, ~(>.
G((,~
~((,~
o~
~((,~
~U~
7
5
3
~
~
o
..
vi
A.
:!E
:J
A.
~
o 1.0
tJ
o
u
...
ce:
to-
~
ce:
u 0.5
o
100
200
300
400
500
NAMEPLATE RATING, MW
FIGURE C-4. CAPITAL COST OF PUMPS
C-20
-------
1.0
NUMBER OF TURBINES
5.0
4.0
*
ID
o
....
cd 3.0
z
Q.,
ii:
u.
o
~
en
o
u 2.0
~
«
~
Q.,
«
u
o
100
200 300
NAMEPLATE RATING, MW
400
500
FIGURE (:-5. CAPITAL COST OF PIPING
C-21
-------
2.0
~
CD TJ SGW = 0.69
0
...
...:
z TJ SGF = 0.84
w
~ 1.5
2:
::;)
0
w
~
Z
-I
0
2: 1.0
«
:x::
-I
«
0
u
I&.
0
I-
(I)
0 0.5
u
-I
«
I-
0::
«
u
0
100 200 300 400 500
NAMEPLATE RATING, MW
FOGURE C-6. CAPSTAl COST OF COAL HANDLING EQUIPMENT
C-22
-------
~
(Q
c
....
~.
z
w
~ 2.0
a..
::>
o
w
~
Z
-'
C
z
« 1.5
~
w
::>
c
en
w
a:
u..
o
~ 1.0
(I)
o
(,J
-'
«
~
a..
«
(,J
3.0 -
2.5
0.5
o
300
100
200
400
NAMEPLATE RATING, MW
FIGURE C-7. CAPITAL COST OF RESIDUE HANDLING EQUIPMENT
C-23
CASES 1, 2, 3, 5 (fw = 0.6)
6, 7 AND 8
CASE 4
CASE 10
500
------
----
-------
1.5
o
CD
o
...
en'
~ 1.0
«
~
en
u.
o
~
en
o
(J
...! 0.5
«
!::
c..
«
(J
100
200 300
NAMEPLATE RATING, MW
400
500
FIGURE C-8. CAPITAL COST OF STACKS
C-24
-------
~
cc
c
...
~.
z
w 20
~
Q.
::)
o
w
a:
o
~
c( .
a: 15
w
Z
w
tf
w
Z
a:I
a:
::)
~ 10
u..
o
~.
CI)
o
(.)
..J
c(
~
~ 5
(.)
25
~
-------
5.
Turbine-Generator Equipment
The capital cost of the turbine-generator equipment in-
cludes the cost of the turbine-generator assembly and the condenser and
associated cooling equipment. Due to the changing steam conditions, two
equations are necessary to fit the data for these costs. The costs are then
adjusted to account for multiple turbines. Figure C-9 shows the total capital
cost for turbine-generator equipment as a function of power.
( P ) O. 725
(CT) = 14.04 x 104 (N~~ . (NT). .
H 1, J
1, J
0.886
(CC) 3 ( PT ) (NT). . PT
= 7. 36 x 10 (N) 85~(N ) :S 500
H T. . 1, J T. .
1, J 1, J
0.352
(CCE) = 5 ( PT ) (NT). .
2. 17 x 10 (NT)..
H 1, J
1, J
(CT)L = (CT) 0.79
H
(CC) = (CT) 0.79 PT
L H (NT). . < 85
1,]
(CCE) = (CT) 0.79
L H
where
CT = cost of turbine generator, $
Cc = cost of condenser, $
CCE = cost of cooling equipment, $
C-26
-------
/
6.
Accessory Electrical Equipment
This cost element is the summation of electrical control
board, switchgear, conduit and cable, inverter, and an intercom system.
CE = 2.83 x 104 PT 0.771
7.
Miscellaneous Power Plant Equipment
This cost element consists of the cost of cranes, for hand-
ling generator room equipment (not refuse), and miscellaneous equipment such
as air compressors, miscellaneous machinery, and fire protection.
CpCR = 2.3 x 103 PT 0.86
4 PO. 24
= 4.63 x 10 T
CM
where:
CpCR = capital cost of power plant cranes, $
CM = capital cost of miscellaneous equipment, $
8.
Air Pollution Control Equipment
Two potential air pollutants are considered in this cost
nl.odel: particulates and 502. The cost of air pollution control equipment
is a function of the flue gas flow rate, efficiency, and the type of device
being used. In this model an electrostatic precipitator is used for control
of particulates in flue gases low in 502 (i. e., from furnaces firing refuse
only) and a wet scrubber is utilized for both particulate matter and 502
control when flue gas arises wholly or partly from coal combustion.
a.
Electrostatic Precipitator
Data from two sources were used to obtain the capital
cost of electrostatic precipitators. Data extracted from Reference C-l (re-
produced as Figure C-I0) were used to scale costs as a function of efficiency
while the additional cost data shown as Figure C-ll were used as the reference
point. The applicable cost equation is as follows:
ClP =
["7p 10.1 (O. 812 V + 60. 4 x 103) + 0.247 V +
3J/( V )0.15
12.7 x 10 5
2. 35'x 10
C-27
-------
o
It)
o
...
()
I
N
00
t;'
8
w
~ 3.0
J::
(,)
a:
;:)
a..
6.0
5.0
EFFICIENCY
4.0
2.0
NOTES:
1.
THE COSTS SHOWN ARE FOR PURCHASE ONLY.
TOTAL INSTALLED COST IS ABOUT 1.7 TIMES
THE PURCHASE COST.
1.0
2.
DATA SOURCE IS REFERENCE C-1.
o
o
8
9
1
2
3
4
5
7
6
GAS VOLUME, 105 ACFM
FIGURE C-10. PURCHASE COST OF ELECTROSTATIC PRECIPITATORS
-------
.5
'\v«..
~~
~,~"
~<,;;
~~
-------
where:
CIP
7Jp
V
capital cost of an electrostatic precipitator, $
=
=
electrostatic precipitator efficiency
=
volumetric flow rate, ACFM
b.
Wet Scrubber
As pointed out in the systems analysis developed in
Section Ill, B, a limestone wet scrubber was selected for S02 removal. The
installed cost of a wet limestone scrubber system is determined from the sum
of the costs of equipment for injecting limestone into the scrubber liquor and
removing calcium sulfate therefrom, of reheating the cleaned gas to give plume-
free stack operation, and of the wet scrubber. Using the data shown in Table
C-ll (obtained from Ref. C-2), the following equations were determined.
where:
where:
4 0.69
CINJ = 2.75 x 10 PF
CINJ = cost of limestone handling equipment, $
PF = plant power derived from fossil fuel, MW
CRH 4 0.8
= 1. 14 x 10 PT
CRH = cost of gas reheater, $
Data were extracted from Reference C-1 to obtain
the capital cost of wet scrubbers. These data are reproduced in Figure
C-12. The applicable cost equation is as follows:
where:
CIWS =
-2
(1. 06 x 10 V + 131. 6) exp (4.25 7J )
w
CIWS =
capital cost of wet scrubber, $
7J
9.
=
wet scrubber efficiency
Waste Handling Equipment
a.
Weigh and Receiving Stations
The capital cost of waste handling equipment consists
of the cost of receiving and storage, cost of scales, and the cost of shredders.
The cost of the receiving and storage area were determined from a cost study
of a conceptual design of a live bottom pit system such as discussed in Section
Ill, B. The cost data are shown in Table C-12. The equation developed for
receiving and storage facility cost (CST) is:
C-30
-------
TABLE C-11
INSTALLED COST OF LIMESTONE SCRUBBER
INJECTION EQUIP:t\1ENT. EXCLUDING WET
SCRUBBER AND REHEAT SYSTEM>:'
200 MW 1000 MW
Total Direct Cost $ 847.000 $2,561.000.
Engineering @ 100/c 84, 700 256,100
Contractor Fees @ 15o/c 127.000 385.000
Contingency @ 100/c 84,700 256.100
Tutal Investment $1,143,400 $3.467.200
Installed Cost of Gas Reheat System
200 MW
Total Direct Cost $ 585.000
Engineering @ 100/c 58.500
Contractor Fees @ l50/c 87.700
Contingency @ 100/c 58.500
Total Investment $ 789.700
1000 MW
$2.125.000
212.500
319.000
212.500
$2.869.000
>"From Reference C-2.
C-31
-------
(,/)
~
...
ri 6
w
CD
CD
=»
a:
CJ
en
...
w
;=
~ 4
t;
o
CJ
w
~
:J:
CJ
~ 2
a.
8
-------
TABLE C-12
COST ESTIMATE SUMMARY OF RECEIVING AND STORAGE
FACILITIES AND EQUIPMENT
2000 TPD Low Profile High Profile
Conveyors $ 459,000 $ 496,600
Receiving Area 188,000 188,000
Storage Pits 685,000 572,000
Total $1,332,000 .$1,256,000
8000 TPD Low Profile High Profile
Conveyors $1,561,000 $1,731,000
Receiving Area 697,000 697,000
Storage Pits 1,949,000 1,547,000
Total. $4,207,000 $3,975,000
NOTE:
Above summary costs include a 30% contingency allowance for
small plants and a 30o/c x 0.67 or 20o/c contingency allowance
for large plants (0.67 size factor).
C-33
-------
CST
= 2.08 x l03 W 0.84
\V
Weighil\g and receiving lIt' ~olid wa~l(' al
-------
z
o
J:::
*
~.
(I)
o
u
0.50
0.40
0.30
0.20
~
'0
~
\
~
?.A
'0
~
0.10
RECEIVING STATIONS
1
10
2
12
COST BASIS, $/H R
TRUCK = 21.75
WEIGHING STATION = 6.00
RECEIVING STATION = 1.63
PLANT REFUSE RATE = 4000 tpd
3
14
4
16
5
18
NO. OF WEIGHING STATIONS
NO. OF RECEIVING STATIONS
FIGURE C-13. TRUCK DELAY AND STATION COSTS
C-35
6
20
-------
for the case of 4000 tpd operation. including the cost of truck delay. The
table below summarizes the optimum number of weigh stations and receiving
stations for various waste loads.
OPTIMUM NUMBER OF WEIGH SCALES
AND RECEIVING STATIONS
Load. Weigh Scales, Receiving Stations,
tpd No. No.
1000 1 3
2000 ..1 6
4000 3 12
6000 4 16
It should be noted that once some minimum number
of stations are provided, the cost is not very sensitive to the further addition
of stations. More specifically, Figure C-13 shows that increasing the num-
ber of weigh stations beyond 3 or the number of receiving stations beyond 14
adds very little to cost of the 4000 tpd case. '
The cost of scales is estimated to be $16, 000 for a
semi-automatic device. This yields a capital cost of:
CSCAL = 16.000 NSCAL
where:
NSCAL = number of weighing stations required as
determined by the queueing study
b.
Shredding Equipment
Three different conditions for shredding the waste
are considered in this model; namely, a 4-inch nominal top-size product and
all waste is shredded, a 2-inch product and all waste is shredded, and a 4-
inch product but only bulky wastes are shredded. It is assumed, on a con-
servative basis, that 2-inch shredding equipment will cost approximately
twice as much as 4-inch shredding equipment. The equations developed for
each shredding condition are presented below:
.
4-inch product and all waste is shredded
3
CSRED = 1420 W w + 340 x 10
.
2-inch product and all waste is shredded
CSRED = 2840 W w + 680 x 103
C-36
-------
.
4-inch product and only bulky waste is shredded
CSRED = 58. 5 W w
10.
Engineering and Construction Supervision
. It was determined that the cos t of engineering and cons truc-
tion supervision varies from 4 to 5% of the total capital cost over the 200 to
400 MW range. Using these percentages, an exponential scaling equation was
developed to predict the cost of engineering and inspection.
CEl
=
0.313 PT -0.343 x (total capital cost)
B.
ANNUAL CAPITAL COSTS
The annual capital costs are deternlined by annualizing the capital
cost, using an appropriate capital recovery factor, and then adding to this a
value to represent the annual cost of insurance and taxes. The model assumes
that the power plant is a privately owned regulated public utility that is subject
to all applicable federal, state, and local taxes and is allowed to earn a Ilfair
rate of return. II
1.
Amortization
The capital recovery faCtor represents the annual percen-
tage that is required to amortize the capital debt at the regulated rate of re-
turn. In equation form:
CRF (r, N) =
N
rO + r)
N
(l+r) -1
where
CRF (r, N)
= annualization rate for an equipment with
a useful life of N years at a return of r
percent
In this report, a 7% rate of return has been as sumed and a value of N (Equip-
ment Life, see Table C-l) has been given to each major piece of equipment.
2.
Federal Taxes
S.ince the profits from a regulated public utility are ideally
a function of the capital investiment, the allowance for federal corporate
income tax can also be computed as a percentage of the capital investment
using the following formula: '
C-37
-------
e
TAX = I:-e (r - ic)
[S + (I - sJ (I - gf(~ N>]
where
TAX = ratio of equivalent annual tax to first cost
e
= federal tax rate
r
= rate of return
i
=
interest rate on debt
c
= debt ratio (total debts to total assets)
s
= salvage value
and
gf(r,
N) = 1. - N [ r ]
r r (l + r)N - 1
For example, if:
r
= 70/0
1
= 6%
= 55%
e
c
= 50%
s
= 0
then the allowance for federal income is found to be 3. 1 % of the capital cost
of the plant. '
3.
Insurance and State and Local Taxes
Insurance has been estimated to cost 0.25% of the plant
costs; data from Reference C-3 indicate that state and local taxes for regu-
lated utilities average 1. 9% of the capital costs.
C.
OPERATION AND MAINTENANCE
1.
Basic 0 & M Costs
The operation and maintenance costs for the combined
firing plant consist of the operating labor shown in Table C-13; the main-
tenance costs for the power plant, the coal costs, plus additional operation
and maintenance costs for shredders and air pollution control equipment.
C-38
L
-------
'~A 3LE C-13
LABOR REQUIREMENT AND COS T
Rate Shift
Categories Dollars/Yr 1 2 3 4
Superintendent 20,000 1
Plant Engineer 17, 000 1
Shift Engineer 15,000 1 1 1 1
Turbine Operator 12,000 1 1 1 .1
Turbine Room Attendant 10,000 1 1 1 1
Control Room Attendant 10,000 1 1 1 1
Incinerator Operator 8,000 O. S/unit 0.5/unit 0.5/unit 0.5/unit
Boiler Operator 8,000 0.25/unit 0.25/unit 0.25/unit 0.25/unit
Tipping Floor Attendant 9, 000 1
1000 tons/day
.Cleanup Labor 6,000 0.6 men
1000 tons/day
0 1 1 1 1
I Ash Cleaning Labor 6,000
w 1 000 ton/ day ash 1000 ton/day ash 1000 ton/day ash 1000 ton/day ash
-.D
Maintenance Mechanic 10,000 0.25/unit 0.25/unit 0.25/unit 0.25/unit
Electrician 14,000 1
Shredder Operator 9,000 1
1000 tons/day
Conveyor Operator 8,000 O. 25/ unit 0.25/ unit 0.25/ unit 0.25/unit
Clerical 6,000 2
Instrument Technician 8,000 1 1 1 1
NOTE:
The cost of labor is increased by 25o/c over the tabular costs to account for fringe benefits.
-------
The annual plant maintenance costs (with the
are estimated to be 100/0 of the capital costs.
rived from the following equation:
exceptio]) of the following items)
The cost of the coal can be de-
CCOAL = 0.73 W FHFCULF
whe re
CCOAL = cost of coal, $/yr
W F = coal rate, tpd
HF = coal heating value, Btu/lb
Cu = unit cost of coal, $/106 Btu1s
LF = plant factor
2.
Shredding 0 & M Costs
Data from Reference C-4 indicate that the operation and
maintenance cost for shredding (excluding operating labor) will vary from
approximately $1. 00 to $0.25 per ton over a range of 10 to 90 tph. Using
this data, an equation was developed for the 4-in. shredder where only
bulky wastes are handled. It is assumed that bulky wastes are 50/0 of the
total.
CMSHRD = 5.8 x 103 (.05 W w)O. 368
where
CMSHRD = operation and maintenance cost of a shredder
in the 10 to 90 tpd range, $/yr
W
w
= waste load, tpd
For cases where all the waste is ground to a 4-in. top-size, several shredders
of the size range noted above are required. To obtain costs for this case, the
single shredder equation above was used and multiplied by the number of shred-
ders required. The resulting cost data were then fit to the following equation.
C = 456 W 0.845
MSHRD w
For the case of shredding to 2-in. top size, it was assumed that the operation
and maintenance cost for the 4-in. top size would be doubled. Figure C -14
shows operation and maintenance cost for shreiding as generated from the
above equations.
C-40
-------
1.0
0.8
z
g
.
t;' 2.INCH SIZE
o
CJ
w 0.6
CJ
z
-c
z
w
() .-
I Z ~
~ ;;:
...... ~
0 0.4
z
-c
z
Q
.- 4-INCH SIZE
c(
a:
w
c..
0 0.2
BULKY WASTE ONLY
2
3
6
7
8
4
5
PROCESSED WASTE LOAD, 103 tpd
FIGURE C-14. OPERATION AND MAINTENANCE COST OF SHREDDERS
-------
3.
Air Pollution Control 0 & M Costs
An equation for the operation and maintenance cost of
electrostatic precipitators is given in Reference C-l as
G = S (J H K + M)
where
G = operation and maintenance cost, $/yr
S
= design capacity, ACFM
J
= power required, kw / ACFM
H = annual operating time, hrs /yr
K = power cost, $/kw-hr
M = maintenance cost, $/ACFM-yr
Reference C-1 gives typical values for J and M of 0.26 x 10-3 kw/ACFM
and $0. 02/ACFM-yr, respectively. Using 8760 hrs/yr and a power cost
of 0.6 mills per kw-hr, the operation and maintenance cost of electrostatic
precipitators becomes
G = 0.024 (ACFM)
The results of this equation are plotted in Figure C-15.
The following equation for the operation and maintenance
cost of wet scrubbers is also given in Reference C-1:
G = S [0.7457 HK (63;6E
Qg
+ 1722F
+ 39~~F) + WHL It MJ
where:
Term
Definition
Typical Value
(Ref. C- 1 )
10
P = pressure drop across fan, in. of water
E = fan efficiency in decimal form
0.6
Q = liquor circulation, gal/ACFM
0.008
g
=
liquor pressure at the collector, psig
13
F = pump efficiency in decimal form
O. 5
C-42
-------
)0
a: 20
,~
(09
CO)
c
...
()
I
of::>
W
~
o
() 15
w
()
Z
e(
Z
w
to-
Z
e(
:!!: 10
C
Z
e(
Z
o
to-
e(
a:
w
~ 5
:l5
o
o
5
6
7
8
3
4
1
2
GAS VOLUME, 105 ACFM
FIGURE C-15. OPERATION AND MAINTENANCE COST OF ELECTROSTATIC PRECIPITATORS
-------
Term
Defini tion
Typical Value
(Ref. C- 1 )
30
h
= physical height liquor is pumped, ft
W = make -up liquor consumption, gal. /hr
ACFM
0.0005
L = liquor cost, $/gal.
-3
0.5 x 10
M = (see previous equation)
0.04
K = (see previous equation)
0.006
H = (see previous equation)
8760
Introducing the Reference C-I values into the equation for operation and
maintenance of wet scrubbers simplifies it to the following:
G = 0.15 (ACFM)
The results of this equation are shown in Figure C-16.
The 0 & M costs of wet scrubbers given above do not in-
clude costs incurred in the handling of limestone and calcium sulfate. There-
fore, an additional cost is necessary. From Reference C-2, the 0 & M costs
associated with limestone scrubbing varies from $373,000 to $1,432,000 per
year over the range of 200 MW to 1000 MW plant sizes. These data were used
to develop the following equation for the 0 & M costs, CMSO' of the ancillary
limestone equipment.
3 5
CMSO = 1. 32 x lOP F + 1. 1 x 10
where
PF
= power derived from fossil fuel, MW
4.
Residue Disposal Costs
The cost of power plant residue disposal is calculated by
assuming 76 cents per ton to place the residue in a landfill plus 20 cents
per ton-mile transportation. Included as residue is 50/0 of the incoming
waste load.
CDIS
= (0.05 W w + ALF) (730 CMlLE D + 365 CL)
C-44
-------
a: 80
~
....
M
o
-
()
I
*'"
UI
tn'
o
(.)
w 60
u
z:
<
2:
w
~
Z
<
~
C 40
Z
-------
where
CDIS
A
= cost of residue disposal, $/yr
= anlOunt of ash, tpd
LF
D
= plant factor
= haul distance, miles
CL = unit cost of landfill, $/ton
CMILE = unit cost of transportation, $/ton-mile
W = processed waste load, tpd
w
D.
POWER GENERATION CREDIT
The amount of credit for power generated is computed by esti-
mating the cost of power in a conventional coal burning power plant with air
pollution control. The annualization factors used for this estimate are the
same as those that were used for the waste-fossil fuel power plant. The
model is summarized in Figure C-17, which shows the cost of power as
a function of plant capacity and fuel cost. Equations for the capital cost of
equipment, annual capital costs, operation and maintenance, and residue
dis posal and coal costs are tabulated in Table C-14.
E.
NET SOLID WASTE DISPOSAL CHARGE
The net solid waste disposal charge or "Disposal Costl', is the
cost of disposing of a ton of refuse in any of the systems discussed herein.
This charge does not include the cost of bringing refuse to the steam generator,
but does include the cost of hauling and disposing of furnace residues at
land fill dumps. The net solid waste disposal charge or cost is computed
from the difference between the total annual costs of operating, the combined-
fired plant and the value of, or cost for, electricity generated by a conventional,
pulverized-coal plant of identical size built under contemporary capital
cost conditions. This cost difference, distributed over the total annual
tonnage of refuse fired, and corrected for plant factor, which is 80% for
both type plants, is the unit refuse disposal cost, expres sed as $/ton.
C-46
-------
10
9
PLANT FACTOR = 0.8
a:
:I:
~. 8
~
.....
en
....I COAL COST
....I
~
1-" 36 CENTS/106 BTU
O
w 7
a:
u
31 CENTS/106 EITU
6
22 CENTS/106 BTU
5
o
100
200 300
PLANT SIZE, MW
400
500
. .
FIGURE C-17. CREDIT FOR THE SALE OF,POWER VERSUS PLANT SIZE
C-47
-------
TABLE C-14
COST EQUATIONS FOR CONVENTIONAL FOSSIL FUEL POWER PLANT
CAPITAL COSTS
.
Land and Land Rights
'.
Piping and Insulation
. Cp =5.9x103PT1.1
e LC = (O. 065 P T + 37) e A
.
Structure and Improvements
CSF = 5.06 x 104 PT 0.755
.
Coal Handling
Ceo = '1. 81 x 104 PT 0.738
.
Stearn Gene rator
.
Residue Handling
CR = 3.66 x 104 A 0.858
CSG = 6.19 x 104 PT 0.914
.
Boiler Water Treatement
-3
A = 4. 21 x 10 W F
Stacks
C
w
3
= 2. 21 x 10 P T
.,
.
Pumps
CpE = 1. 11 x 104 P TO. 73
Cs = 141 W F
.
Air Pollution Control Equipment
.
Turbine-Generator Equipment
CT =,14.04x104PTO.725
Cc = 7. 36 x 103 PT 0.886
CeE = 2.17 x 105 PTO. 352
eIWS = (1. 06 x 10-2V + 131. 6)
exp (4. 257Jw)
4 0.69
C INJ = 2. 75 x lOP T
C RH = 1. 14 x 1 ° 4 P TO. 8
.
Accessory Electrical Equipment
CE = 4.84 x 104 PT 0.71
.
Engineering and Inspection
CEl = 1. 03 x 105 PT 0.495
.
Miscellaneous Equipment
3 0.86
CpCR = 2. 3 x 10 PT
e = 4.63 x 104 P O. 24
M T
OPERATING &
MAINTENANCE COSTS
.
O&M Costs
C c:: 2 7 P -0.225 (8760) P
OM . T T
CCOAL = 0.73 WFHFCULF
.
Coal Cost
C-48
-------
III.
TRANSPORTATION COST MODEL
The transportation cost model permits some additional insights into
the total cost of disposal. As a general rule, the economies of scale "Nill
indicate that the unit cost of disposal will continue to decrease as the total
tonnage increases. However, this waste must come from farther and
farther out, thus increasing the haul costs. At some point these additional
costs will outweigh the economies of scale as illustrated below:
Cost
$/ton
Total haul and
disposal cost
Haul cost
Disposal cost
Tons/ day
The transportation cost model computes the cost of hauling waste
to the steam generator. In terms of generally accepted solid waste ITlanage-
ment definitions, this cost embraces the expense s of hauling refus e, in
vehicles that are already fully loaded on their routes or have completed
collection routines, to the disposal site. Transfer operations, if
applicable, are normally included in this cost. The model computes
the transpartation by multiplying a unit cost (e. g., $/ton-mile) by the
haul dis tance and waste load where the unit cos t is a function of vehicle
speed. The requirement then is to sum up the products of unit cost, dis-
tance, and the correspondingly located waste load over the region of
interest. For a large number of closely spaced units, as would be the
case for transporting waste from households to a centrally located plant,
thes e products can be considered continuous, thus allowing the summation
to be replaced by integration. The equation then for the cost of transportation
1S:
CTR =
J
R
,...
'-'r
. r d w
J
R
dw
C-49
-------
whe re
= transportation cost, $/ton
CTR
C
r
= unit transportation cost, $/ton-mile
r
= haul distance, miles
dw
= differential waste load
R
= region of interest
To evaluate this equation, dw must be determined. If it is assumed
that waste would be hauled to a centrally located plant, i. e., the plant is in
the center of the hauling area, but not neces sarily at the population center,
then:
dw
= W'RP d (x, y) dJ:C dy
where:
Pd(x, y} = population density as a function of x and y
WI
R
= per capita waste load, tons / cap. -day
The population density distribution is not known precisely for the SlX
regional study areas considered in this program. This being the case, a
population distribution function must be assumed. A normal (Gaussion)
distribution seems reasonable as a first approximation, even though the
maximum population density may not be at the center. This is because
population is used only to represent the ultimate requirement of waste
load and there is a large quantity of commercial wastes in the center of
a metropolitan area. With this assumption, the population density can
be expressed using the probability distribution equation:
P d (x, y) =
1
21TU
x
U
Y
exp
-t [(X~:X) + c;y~yn
where:
u = standard deviation in the x direction
x
u = standard deviation in the y direction
y
fL = mean value of x
x
fL y = mean value of y
C-so
-------
If it is as sumed that Uy = ux' and that T p is a scale factor of the total
population in the area which converts the unit normal distribution to the
waste load spatial distribution, then:
d w =
WI"~ T
R P exp
2 Tr u2
- ~ [(x-
)2 '
}J- +
x
u2
(Y-I'y? ]
dx dy
~
where: '
T :: total population in the area
,p
The concepts discussed above are shown pictorially in Figure C-l8.
To evaluate P d (x, y) for any given area, it is necessary to deternline
U for that area denslty by assuming that the total population given for a study
area is contained in 99% of the total area under the normal surface. This
corresponds to a radius of 3u and therefore:
r = (. ~ )0. 5
TrPd
= 3u
1
(J - -
- 3
( )0.5
Tp
TrPd
where:
P d = average ,population density, cap. /mile2
The unit transportation cost is a function of vehicle speed which,
typically, is also influenced by haul distance. Using data in Reference C-5,
an equation was developed to expres s vehicle speed as a function of haul
distance. Using $21. 75 per hour as the cost of a 5-ton truck, the unit cost
of transportation becomes:
C - 0.57 + 0.0916
- (x2 + y2) 1/2
Substituting for P d' dw, u, and C, the transportation cost equation
becomes:
C-5l
-------
()
I
V1
N
p
I
/v
.....
,
\
\
\
I
\
\ ~y I
\ /
',4f.J-x -.It:> //
....._~-,..
I
'REGeON OF
INYEAESY
x
TYPICAL STUDY AREA
FIGURE C-18. '-( MAL POPULATION : STR~rin TiOW ~ A TYP CAl S '~DY A ~EA
-------
~
+r +a
JJ
-r -a
CTR = +r +a
JJ
-r -a
I
.z
(b exp 1. 14 c) + o. 183 (x2 ty2)
dx dy
b exp c dx dy
where:
a =
I
Z
2 2.
(r - y )
b = 4. 5 P d WI R
1 4.511" Pd
c = - T
P
[ (x " 1')2 + (y - I' y)2 ] \
This is solved by numerical integration for a preselected collection
radius and plant location relative to the center of the study area.
The parameters fLx and fLy' can be chosen to position the plant site at
any desired location; i. e., the plant site is located a distance from the cen-
ter of the area equal to fLx and fLy in a rectangular coordinate system.
C-53
-------
IV.
REFERENCES
C-l.
C-2.
C-3.
C-4.
C-5.
"Control Techniques for Particulate Air Pollutants, II U. S.
Department of Health, Education, and Welfare, Public Health
Service, Jan. 1969, No. AP-51.
"Sulfur Oxide Removal from Power Plant Stack Gas, Use of
Limestone in Wet-Scrubbing Process, " prepared for National
Air Pollution Control Administration, U. S. Department of
Health, Education, and Welfare by Tennessee Valley Authority,
Contract No. TV -29233A.
"National Power Survey, " Federal Power Commission 1964,
Part I, Page 283.
"Solid Waste Handling and Processing, " presented by Neil L.
Drobny, Battelle Memorial Institute, at Joint Meeting of
Research and Special Technical Committee and Industrial
Incineration Committee, ASME Incinerator Division, New
York, New York, January 15, 1969.
"Refuse Collection Practice, " Prepared by Committee on
Solid Wastes, American Public Works Association, 1966.
C-54
-------
APPENDIX D
BIBi IOGRAPHY
Jo.
-------
r
1.
SUMMARY OF CONTENTS
The following compilations list reasonably current and accessible
information sources that deal with subjects falling within the basic scope
of the present report. Thus, while the broad fields of steam generation,
air pollution, and waste management have been searched, only those pub-
lications that clearly relate to refuse-fuel steam systems have been cited.
In the case of writings on novel or conceptual schemes for refuse InCInera-
tion or handling, considerable latitude of selection was observed.
The inclusion of literature dealing primarily with conventional refuse
incineration has been avoided, except that which goes to air pollution aspects.
'J.'he pollutants emanating from burning refuse will obviously be qualitatively
similar regardless of whether the furnace is of the heat recovery type or not.
An excellent bibliography (544 citations) on conventional refuse incineration
and related subjects is contained in Reference 203.
This bibliography has been divided into seven topical groupings. Each
is organized alphabetically according to author I s nam.e or is suing agency.
Because of the contemporary nature of this technology, no publication dating
earlier than 1962 has been cited. Particularly where publications of greater
technical depth are available on the same subject, citations of news-type
articles have generally been avoided. ,Titles placed in parentheses are
translated versions.
"
D-l
-------
II.
STEAM GENERATION WITH WASTE FUEL
1.
2.
3.
4.
5.
6.
8.
Andritzky, M., "(Refuse Power Plant Munich)," Brennstoff-
"
Warme-Kraft, 14 (5), 232-3 (1962).
Andritzky, M.. "(The Second Expansion of the Munich Refuse
"
Power Plant)," Brennstoff-Warme-Kraft, 16 (8), 403 (1964).
Angenend, J.. "(The Incineration of Residential and Industrial
Wastes in the RW E Power Plant, Es sen-Karnap)," Techn.
Mitteilungen. 55 (6), 270-78 (1962).
Anon., "(Rotterdam Gets the Biggest Refuse Incinerator in the
World)," Energie. ~ (12). 443 (1969).
Bachl, H., and Maikranz, F., "(Experience with Refuse In-
cineration in a High Pressure Steam Power Station), 11 Energie,
1 7 (8). 317-26 (1965).
Bachl, H., "(District Heating, Waste Incineration and Electric
Night- Tariff Heating and Air Pollution Control in Munich), It
Staub-Reinhaltung der Luft, 28 (2), 17-27 (1968).
7.
Bachl, H., "(Cost Comparison Between an Oil-Fired Power
Plant and a Multiple Purpose Power Plant (W ith District Heat
Output and Refuse Incineration», It Brennstoff- W1:Lrme -Kraft,
21 (9), 457-60 (1969).
Bauer, H., Michna, L.. and Geer, G. L., 'I(Additional District
Heat from the Expansion of the Stuttgart Refuse Incineration Plant). II
Elektr. -Wirtsch.. 68 (25), 806-11 (1969).
9.
Beningson, R. M., and Beningson, H. E., II The Utilization of
Solid Waste as a Source of Energy' for District Heating and
Cooling Systems. " presented at the 1 st Int. District Heating
Conv., London, April 1970.
10.
Cannon. Co N.. "Utilization of Heat from Refuse Incineration
for Power Generation. II presented at the ASME, Incinerator
Division, 14 March 1968.
11.
Cohan, Lo J. , and Fernandes, J. H., "Potential Energy Con-
version Aspects of Refuse, It ASME Pub!. 67-WA/PID-6.
12.
Connell, J. M.. ItSolving Two Major Problems of a Modern
City," Heat Eng., 40 (9/10), 64-71 (1965).
D-2
-------
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
Deming, L. F., and Connell, J. M., "The Steam Generating In-
cinerator Plant, " Proc. Amer. Power Con£., 28, 652-60 (1966).
Diamant, R. M. E., "Refuse Incineration for Urban Heating
Systems, II Air Cond., Heating & Vent., 65 (6), 21 (1968); ibid.,
65 (8), 18 (1968); also see Steam & Heating Eng., ~, 16-ZT"(T966).
Dvirka, M., and Zanft, A. B., IIAnother Look at European In-
cineration Practices, II Public Works, 98 (7), 99-100 (1967).
Eberhardt, H., "European Practice in Refuse and Sewage Sludge
Disposal by Incineration - I, II Combustion, 38 (3), 8-15 (1966).
Eberhardt, H., and Mayer, W., IIExperiences with Refuse In-
cinerators in Europe - Prevention of Air and Water Pollution"
Operation of Refuse Incineration Plants Combined with Steam
Boilers, Design and Planning," Proc. 1968 Nat. Incinerator
Conf., New York, 5-8 May 1968, pp 73-86.
Eckhardt, F., "( The Refuse Incineration Installation at Berlin-
Ruhleben), 11 Chemie-Ing. -Techn., ~ (10) 606-610 (1969).
Engdahl, R. B., and Hummell, J. D.,IIPower from Refuse, II Amer.
City, 83 (~), 119 and ££'(1968). --
Engel, W., and von Weihe, A., II(Experimental Refuse Incineration
Plant of the DL;.sseldorf Municipal Works, Flingern Power Plant), II
Brennstoff-WJ:trme-Kraft, !! (5), 234-6 (1962).
Fichtner, W., et aI, "The Stuttgart Refuse Incineration Plant:
Layout and Operation Experience, " ASME Pub!. 66 - W A/PID-10.
Fife, J. A., IIDesign of the Northwest Incinerator for the City
of Chicago, II Proc. 1970 Nat. Incinerator Con£., Cincinnati,
17-20 June 1970, pp. 249-60.
Forbert, G., "(Waste Incinerator at Hagen), II StJ:tdtehygiene, 20
(4), 86-94 (1969).
Gampper, R., "(Stuttgart's Refuse Incinerator, II Mitteilungen
der VGB, 86, 329-31 (1963).
Geer, G. L., II(Refuse Firing at the Stuttgart MUnster Power
Plant), 11 Stlldtetag, .!1 (1), 52-54 (1966).
Geer, G. L., II(Soon Higher Availability; the Third TWS-Refuse
Boiler - A Boiler Without First Generation Problems), II Energie-
Wirtsch., 19 (7/8), 307-10 (1969). --
D-3
-------
27.
28.
29.
30.
31.
32.
33.
34.
Gerhardt, P., Jr., 1'lncinerator to Utilize Waste Heat for Steam
Generation," Public Works, 94 (5), 100-1 (1963).
Goepfert, J., and Reimer, H., 11(Refuse Incinerator in Frankfurt
am Main), '1 Energie, 20 (7/8), 195-7 (1968).
Goepfert, J., "(Planning and Construction of the New Refuse In-
cineration Plant for Bremen)," Brennstoff-W~rme-Kraft, 21 (9),
481-84 (1969).
Green, B. L., "Boiler for Bark-Burning," Power Eng., 72 (9),
52-3 (1968).
Hammerlei, H., "(Should Refuse Incineration Plants be Built
With or Without Heat Utilization?)," Tech. Rdsch. (Bern), 21,
9-13 (1969). -
Hansen, E. G., and Rousseau, H., "An Engineering Approach
to the Waste Disposal Crisis," Combustion, ~ (9), 8-13 (1970).
Hart, S. A., "Solid Wastes Management in Germany; Report of
U.S. Study Team Visit, June 25-July 8, 1967," USPHS Publ.
1812, Washington, D. C., 1968.
Hilsheimer, H., "Experience After 20,000 Operating Hours -
the Mannheim Incinerator, 11 Proc. 1970 Nat. Incinerator Coni. ,
Cincinnati, 17-20 May 1970, pp 93-106.
35.
Hitchcock, C. Y., liThe Salvage Fuel Boiler Plant at Noriolk,
Virginia, U. S. A., 11 presented at the Incinerator Conf., Inst.
of Fuel, Brighton (England), 25 -26 Nov. 1969.
36.
Hotti, G., 11Montreal Incinerator is Twofold Innovator. II Power,
112 (1). 63-5 (1968).
37.
Hotti, G., and Tanner, R., IIHow European Engineers Design
Incinerators," Amer. City, 84 (6), 107 and ff (1969).
38.
Howard, J. B., "Combustion of Solid Refuse. " ASME Publ.
68-WA/INC-2.
39.
Jensen, M. E., 110bservations of Continental European Solid
Waste Management Practices. 11 USPHS. Bureau ()f Solid
Waste Management, Publ. 1880, 1969.
40.
Jesson, H. E., and Rolfe, T. J. K., "Refuse Incineration -
Current Practice," BCURA Research Report 358, August 19o5.
D-4
-------
.H.
42.
43.
44.
45.
,46.
47.
48.
49.
50.
51.
52.
r :'; ',~ :'".'~ ;. '.
. " ..:. ~ ';' "," ',~.. ~.~ . .'. !r :'.
Kachulle, C., "(Reflt'sc fncinerating Plan.ts With or Withuut Heat
Utilization. A Main Subject of the Third Conference of the Inter-
national Working Group for Refuse Research, Trient, 1965),"
Brennstoff-W~rme-Kraft, 17 (8), 391-5 (1965).
Kalika, P. W., and Seibel, J. E., "Technical-Economic Study
of Solid Waste Disposal Needs and Practices, 11 Combustion En-
gineering, Inc., Report to the USPHS on Contract Ph 86-66-163,
1 Nov. 1967.
Kallenbach, K., "( Trash Incineration Plant with Roller Grate
Firing for the City of Hagen)," Brennstoff- W !irme -Kraft, 16 (8),
406-7 (1964). -
Kammerer, H. F., "(Refuse Incineration Plant with Heat Re-.
co very in Stuttgart)," Brennstoff-W~rme-Kraft, 14 (10), 476..68
(1962)~ -
Kaupert, W., "Refuse Incineration with Heat Recovery, " presen-
ted at the 9th Int. Con£. Assoc. Pub. Cleansing, Paris, 26-30 June
1967.
Kern, A., "(Views on the Design of Modern Incineration Installa-
tions for Urban Trash)," Brennstoff-Wa'.rme-Kraft, 14 (5), 22:5-7
(1962). -
Knoll, H., "(Refuse Incinerating Plant of the City of Nuremberg), II
Brennstoff-WJirme-Kraft, .!2. (12), 595 (1965).
Kutzschbauch, K., and Bunde, H., "(Refuse Incineration and the
Possibilities for Its Industria] Application)," Energie und Technik,
.!1. (7), 319-23 (1969).
Lauer, H., "( The Status of Refuse Incineration), " Aufbereitungs-
Technik, 4, 174-76 (1968).
Lieberg, O. S., "Heat Recovery From Incinerators, Part I, II
Air Con d., Heating & Vent., 62 (6), 53 -7 (1965); Part II: ibid,
62 (7), 73-4 (1965). -
Lorenzini~ R. A., "Solid Waste Heat Recovery," Power Eng." 73,
37-39 (1969).
Maikranz, F., "(Incineration of Refuse and Heat Recovery, Ex-
perience with Mixed Firing), " Mitteilungen del' VGB, 48 (2),
111-118 (1968). ' -
D-5
-------
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
Maikranz, F., "The Munich Plant: User's Experience," pre-
sented at the Incinerator Conf. Inst. of Fuel, Brighton (England),
25 -26 Nov. 1969.
McKenzie, E. C., and Scott, D. H., "The Design of Combustion
Equipment for Waste Material: A General Review, " presented at
the Incineration Con£. Inst. of Fuel, Brighton (England), 25-26
Nov. 1969.
Moegling, E., "(Practical Aspects of Refuse Incineration Based
"
on the Example of Essen-Karnap)," Brennstoff-Warme-Kraft, 17
(8), 383-91 (1965).
Moore, H. C., and Reardon, F. X., "A Salvage Fuel Boiler Plant
for Maximum Steam Production, " Proc. 1966 Nat. Incinerator
Con£. , New York, 1-4 May 1966, pp 252-258.
Moore, H. C., "Refuse Fired Steam Generator at Navy Base,
Norfolk, Va.," Proc. MECAR Symp. Incineration of Solid
Wastes, New York, 21 March 1967, pp 10-21.
M9Srch, 0., "District Heating for Existing Cities as Well as
New Towns and the Use 0-£ Refuse Incineration as a Base Supply
for the Heating, " presented at the 1 st Int. District Heating Conv. ,
London, April 1970.
Mutke, R., K8rbel, W., and Steller, P., "(Possibilities for
Heat Utilization in Refuse Incinerating Installations), " Mitteil-
ungen der VGB, 50 (2), 113-17 (1970).
Nowak, F., "~Experience with the Refuse Incinerator at Stuttgart),"
Brennstoff-Warme-Kraft, .!l (2), 71-6 (1967).
Nowak, F., "Considerations in the Construction of Large Refuse
Incinerators, "Proc. 1970 Nat. Incinerator Conf., Cincinnati,
17-20 May 1970, pp 86-92.
Nuber, K., 1'(Process Testing of the Rosenheim Refuse Incinera-
tion Plant), " Kommunalwirtsch., .!..' 42-5 (1969).
Palm, R., "( Thoughts on the Combined Firing of Sewage Sludge
"
and Refuse on Furnace Grates), " Brennstoff- Warme -Kraft, 18,
223-26 (1966).
,
Pepe, P. D., and Turner, G. M., "Design of the First Large
United Kingdom Power Producing Refuse Disposal Plant, " Proc.
Inst. Mech. Eng. , 183, Part ~ (24), 527-44 (1968-69). -
D-6
-------
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
:" ':# ',.'; .:.
Perl, K., 1I( The Planning of Plants for the Disposal of M\.111icipal
II
Wastes), 11 Stadtereinigung, .!:..., 9 -11 (1969).
Pope, M., and Deming, L. F." IIRefuse for Fuel Makes Econo-
mical Saline Water Conversion, 11 Combustion, ~ (7), 20 -21 (J. 966).
Porteous, A., IITowards a Profitable Means of Waste Disposa.l, 11
ASME Publ. 67-WA/PID-2.
Presuhn, A., II(Cost Problems in the Combustion of Refuse,
Based on the Data of Power Plant Nord of the Municipal Elec-
tricity Works, Munich), 11 Brennstoff-W~rme-Kraft, 19 (10),
489-92 (1967). -
Rasch, R., "(Furnace Systems for Refuse Incineration), II
Brennstoff-W!:lrme-Kraft, ~, 376-82 (1964).
Rasch, R., "(Incineration Plants for Municipal and Industrial
Wastes), II Energie, ~ (7/8), 239-49 (1969). .
Rasch, R., II(Refuse and Waste Incineration - Present Day
Technological Status and Future Developments Resulting From
Changes in the Composition of Refuse )," Chemiker Zeitung,
93 (10), 369-78 (1969).
,
Regan, J. W., Mullen, J. F., and Nickerson, R. D., IISus-
pension Firing of Solid Waste Fuels, II Proc. Amer. Power
Conf., 31, 599-608 (1969).
Regan, J. W., 11 Generating Steam from Prepared Refuse, 11
Proc. 1970 Nat. Incinerator Conf., Cincinnati, 17-20 May
1970, pp 216-,223.
Rogus, C. A., IIAn Appraisal of Refuse Incineration in Western
Europe," Proc. 1966 Nat. Incinerator Con£., New York, 1 -4: May
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Rogus, C. A., IIHarrisburg Incinerator - Highlights of Design, 11
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76.
Rogus, C. A., IIIncineration with Guaranteed Top-Level Per-
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77.
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D-7
-------
78.
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Sebastian, F. P., ArieYi A. F., and Garretson, B. B., "Modern
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D-8
-------
91.
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93.
94.
95.
96.
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98.
100.
101.
102.
103.
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430-2(1968). --
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"Study of Power Generation Based on the Utilization of Low Grade
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"Special Studies for Incineration for the Government of the Dis-
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99.
Velzy, C. R., and Velzy, 0., "Unique Incinerator Develop s
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(4), 90-5 (1964).
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tions)," Mitteilungen der VGB, 79, 232-38 (1962).
Wangerin, D. D., "Are We Getting the Most Out of Byproduct
Fuels? , 11 presented at the ASME Ind. Fuels Con£., St. Louis,
11-13 Feb. 1969.
Winkins, H. P., "(Reheat Power Plant Using Refuse Firing on
Friesenheimer Island in Mannheim), II Energie. and Technik, 16
(7), 211 (1964).
Winkins, H. P., "(Questions About Waste Incineration Based on
. "
the Mannhelm Example)," Stadtetag, 22 (11), 569-73 (1969).
D-9
-------
104.
105.
106.
107.
108.
109.
110.
Winkens, H. P., "The Application of District Heating to Existing
Town Centres and New Town Districts Related to Mannheim, "
presented at the 1 st District Heating Con v., London, April 1970.
Wisely, F. E., ct aI, "Study of Refuse as Supplemental Fuel
for Power Plants, rf Horner and Shifrin, Inc., Report to the
City of St. Louis, Mo., on Bureau of Solid Waste Management
Grant No. 1-D01-U1-001 76-01, March 1970.
Wolf, M., and Jacobi, J. M., "(Refuse Burning)," Brennstoff-
W~rme-Kraft, .!..2. (4), 191-3 (1967).
Wuhrmann, K. A., "(Possibilities and Limits of Waste Incine-
ration)," Aufbereitungs-Technik, 5 (9), 506-7 (1964).
Wqhrmann, K. A., "Pros and Cons of Heat Recovery in Waste
Incineration, II presented at the Amer. Pub. Works Assoc.,
Inst. of Solid Wastes Meeting, Boston, 5 Oct. 1967.
Zankl, W., II{ The Cell Grate Trash Disposal Installation), "
" 6
Brennstoff-Warme-Kraft, ~ (5), 224-5 (19 2).
Ziemer, G., and Drewes, W., "(Operation and Experience
With the Karnap Refuse Incinerator), II Elektr. - W irtsch., 67
(18), 547-52 (1968).
III.
CORROSION
111.
112.
113.
114.
. 115.
116.
Angenend, J., "( The Behavior of Boiler Tube Materials in
Gases Containing HC1), II Brennstoff-W~rme-Kraft, 18 (2),
79-81 (1966). -
Bryers, R. W., and Kerekes, Z., "Recent Experience With
Ash Deposits in Refuse Fired Boilers, II ASME Publo 68-WA/CD-4.
DefEkhe, J., "(Corrosion in Refuse Incinerators), " MU.ll, Abfall,
Abwasser, .!2:., 3-7 (1969).
F~ssler, K., Leib, H., and Sp~hn, H., "(Corrosion in Incine-
rator Plants)," Mitteilungen der VGB, 48 (2), 126-38 (1968).
Fink, F., "(The Firing of Domestic Refuse with a Higher Content
of Plastics), " Brennstoff- W~rme-Kraft, ~ (9), 472 -76 (1969).
Hirsch, M., "(Flue-Gas-Side Corrosion of Heat Exchange Sur-
faces in Refuse Firing Plants by the Formation of Iron Chloride), II
Energie, 20, 32-5 (1968).
D-IO
-------
11 7.
118.
119.
120.
121.
122.
123.
124.
125.
126.
127.
128.
Hirsch, M., and Rasch, R., "(On the Formation of Iron Chloride
Through the Reaction of Hydrogen Chloride in Flue Gases and
Iron Oxide in Fly Ash and on Heat Exchange Surface), "Auf-
bereitungs - Technik, ~ (12), 614-23 (1968)
Huch, R., "(Hydrochloric Acid Corrosion in Refuse Burning
Installations)," Brennstoff-Warme-Kraft, ~ (2), 76-79 (1966).
K8hle, H., "(Fireside Deposits and Corrosion in Refuse Boilers), 11
Mitteilungen del' VGB, 102, 177-79 (1966).
Nowak, F., "(Corrosion Phenomena in Refuse Boilers), 11 Mittei-
lungender VGB, 102 (6),209-10 (1966); also see ibid, 11l~r--96,
(19b7). -
Nowak, F., "(Corrosion Phenomena in Refuse Firing Boilers
and Preventive Measures), II presented at the Int. Symp. on
Corrosion in Refuse Incineration Plants, VGB, DUsseldorf,
April 1970. .
Perl, K., "(Corrosion Damage to Steam Generators of Refuse
Burning Plants)," Energie, ~ (8), 353-4 (1966).
Rasch, R., "(Concerning the Disintegration of Protective Iron
Oxide Coatings on Heat Exchange Surface of Slagging, Refuse-
Firing Furnaces as the Cause of Initial High- Temperature
Corrosion}," Aufbereitungs-Technik, ~ (5), 237-44 (1969).
Rasch, R., "(Corrosion When Firing Refuse:
Group of the 4th International Congress of the
"
Warme-Kraft, ~ (9), 495-6 (1969).
Report of the 3rd Work
lAM}," Brennstoff-
Rasch, R., "( Thermodynamic, High Temperature, Fire-Side
Corrosion in Waste Incineration Plants}," MUll, Abfall, Ab-
wasser, ~ (12), 34-37 (1969).
Som!TIerlad, R. E., I.' Tube Wastage in Refuse Burning Installa..
tions, II presented at the ASME, Incinerator Division, Design
Committee Meeting, New York, 14 Jan. 1970.
Steller, P., "(Experiments for Clarifying the Causes of Corro-
sion in Incinerating Plants)," Energie, 18, 355-57 (1966); also
see ibid, 19 (9), 278-80 (1967). -
Wickert, K., "(The Accelerators of Corrosion in Furnaces),"
"
Warme, 74 (4), 103-109 (1970).
D-ll
-------
IV.
BOTTOM RESIDUES
129.
130.
131.
132.
133.
134.
135.
136.
137.
138.
v.
Bowen, 1. G., and Brealey, L., "Incinerator Ash-Criteria of
Performance, "Proc. 1968 Nat. Incinerator Con£. , New York,
5-8 May 1968, pp 18-22.
Braun, R., "( To What Extent Should Refuse be Burnt? Ideas
on the Quality of Combustion Products When Burning Refuse), "
Brennstoff-W!:trme-Kraft, ~ (9), 409-11 (1968).
Cohan, L. J., "A Proposed Method to Establish Standards for
Residue Quality, " presented to the ASME Incineration Division,
Grate and Combustion Subcommittee, June 1968.
Hampton, R. K., and Roberts, J., "Incinerator Refuse-Residue
and Fly-Ash Materials Handling, II ASME Paper 62-WA-343.
Hawkins, G. A., "The Residue Tells the Story, II Amer. City, 78
(9), 104-6 (1963).
Kaiser, E. R., Zeit, C. D., and McCaffery, J. B., "Municipal
Incinerator Refuse and Residue," Proc. 1968 Nat. Incinerator
Con£. , New York, 5-8 May 1968, pp 142-53.
Kenahan, C. B., et aI, "Composition and Characteristics of
Municipal Incinerator Residues," Bureau of Mines Pub!. 7204,
Dec. 1968.
"The Residue Situation - Current and Future, " National Academy
of Science, National Research Council, Committee on Pollution,
Appendix 4 of "Waste Management and Control, " Committee on
Pollution, Publication 1400, 1966.
Purdom, P. W., rrCharacteristics of Incinerator Residue, "
presented at 1 st Annual Meeting Inst. Solid Wastes, Chicago,
Sept. 1966.
Schoenberger, R. J., and Purdom, P. W., "Classification of
Incinerator Residue, "Proc. 1968 Nat. Incinerator Conf., New
York, 5-8 May 1968, pp 237-41.
REFUSE CHARACTERISTICS
139.
Abrahams, J. H., and Cheney, R. L., "The Role of Glass Con-
tainers in Solid Waste Disposal," Bull. Glass Container Manu£.
Inst., New York, undated.
D-l2
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140.
141.
142.
143.
144.
145.
146.
147.
148.
149.
150.
Bell, J. M., II The Physical and Chemical Composition of
Municipal Refuse," The APWA Reporter, 29 (1), 11 (1962);
also see Proc. of the Nat. Con£. on Solid waste Research,
APWA, Chicago, 1963, pp 28-38.
Black, R. J., et aI, II The National Solid Wastes Survey - An
Interim Report:"Presented at the 1968 Annual Meeting, Inst.
for Solid Wastes, Miami Beach, Florida, 24 October 1968.
Calhoun, J. C., Jr., et aI, "Solid Wastes, 11 Environmental
Pollution Panel, President's Science Advisory Committee,
The White House, November 1965.
"California Integrated Solid Wastes Management Project, A
Systems Study of Solid Wastes Management in the Fresno Area,. II
(State of) California, Dept. of Public Health, 1968.
Carruth, D. E., and Klee, A. J., "Analysis of Solid Waste
Composition - Statistical Technique to Determine Sample Size, II
USPHS, Bureau of Solid Waste Management, Publ. SW -19ts,
1969.
Cohan, L. J., and Fernandes, J. H., liThe Heat Value of
Refuse, II Mech. Eng., ~ (9), 47-51 (1968).
"Genesee County Solid Waste Disposal Study, II Consoer,
Townsend & Associates, Inc., Report on USPHS Grant
I-DOI-UI-00070-01, April 1968.
Darney, A., and Franklin, W. E., II The Role of Packaging
in Solid Waste Management, 1966 to 1967, II USPHS, Bureau
of Solid Waste Management, Report SW -5c, 1969; also see
Envir. Sci. & Tech., 2. (4), 328-33 (1969).
Eliassen, R., et aI, "Solid Waste Management - A Compre-
hensive Assessment of Solid Waste Problems, Practices, and
Needs, II Ad Hoc Group Report for Office of Science and Tech-
nology, Washington, D. C., May 1969.
Etzel, J. E., and Bell, J. M., "Methods of Sampling and
Analyzing Refuse, II The APWA Reporter, 29 (11), 2-4, 18-21
and ff (1962).
Etzel, J. E., and Bell, J. M., "A Report on the Sampling and
Composition of Municipal Refuse to Bloomington, Indiana, 11
Purdue University, 1967.
D-13
-------
151.
152.
153.
154.
155.
156.
157.
158.
159.
160.
161.
162.
Foster, W. S., "Municipal Solid Waste Disposal. Part I.
Nature and Magnitude, " Amer. City, '!2 (2), 105-7 (1962).
Fulmer, M. E., and Testin, R. F., "Report on the Role of
Plastics in Solid Waste," prepared for The Society of the
Plastics Industry, Inc., by Battelle Memorial Institute,
Columbus Laboratories (undated).
Golueke, C. G., and McGauhey, P. H., IIComprehensive
Studies of Solid Wastes Management," First Annual Report
SERL 67-7, Sanitary Engineering Research Lab., University
of California Berkeley, May 1967.
H!{feli, R. J., "Refuse Analyses," International Research
Group on Refuse Disposal, Bull. 15, August 1962, pp 16-20.
Hamm, H. W., "Equivalent Heat Energy in Refuse," Power,
112 (10), 132 (1968).
Hickman, H. L., Jr., "The Physical and Chemical Charac-
teristics of Municipal Solid Wastes," USPHS, Solid Wastes
Program, Cincinnati, 1968.
Ingram, W. T., and Francia, F. P., "Quad City Solid Wastes
Project - Final Report," USPHS, Solid Waste Program, Cin-
cinnati, 1968.
Kaiser, E. R., "Refuse Composition and Flue-Gas Analyses
from Municipal Incinerators," Proc. 1964 Nat. Incinerator
Conf., New York, 18 -20 May 1964, pp 35-51.
Kaiser, E. R., "Combustion and Heat Calculations for In-
cinerators, " Proc. 1964 Nat. Incinerator Conf., New York,
18 -20 May 1964, pp 81-89.
Kaiser, E. R. D "Chemical Analyses of Refuse Components, II
Proc. 1966 Nat. Incinerator Conf., New York, 1-4 May 1966,
pp 84-88.
Kaiser, E. R., "Composition and Combustion of Refuse, II Proc.
MECAR Symp. Incineration of Solid Wastes, New York, 21 March
1967, pp 1-9.
Kaiser, E. R., Zimmer, C., and Kasner, D., "Sampling and
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D-14
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163.
164.
165.
166.
167.
168.
169.
170.
171.
1 72.
1 73.
Kennedy, J. C., "Seasonal Variations in Municipal Solid Waste
Output, " presented at the Eng. Found. Res. Con£., Solid Waste
Research and Development, Milwaukee, 24-28 July 1967.
Muhich, A. J., Klee, A. J., and Britton, P. W., "1968 National
Survey of Community Solid Waste Practices - Preliminary Data
Analysis," USPHS Publ. 1867, 1968.
Niessen, W. R., and Chansky, S. H., "The Nature of Municipal
Solid Waste," presented to the ASME, Incinerator Division,
15 May 1969; also see Proc. 1970 Nat. Incinerator Conf., Cin-
cinnati, 17-20 May 1970, pp 1-24.
Rogus, A., "Refuse Quantities and Characteristics," Proc.of
the Nat. Conf. on Solid Waste Research, APW A, Chicago, 1963,
pp 17-27.
Rogus, C. A., "Refuse Collection and Refuse Characteristics, "
Public Works, 97 (3), 96-99 (1966).
Russ, H., "(Combustion Calculations for Refuse with Charac-
teristic Fuel Values), 11 BrelJ.nstoff-W~rme-Kraft, 21 (3), 125-29
(1969); also see ibid, ~ (9), 467-72 (1969). -
Schoenberger, R. J., Trieff, N. M., and Purdom, p. W.,
"Special Techniques for Analyzing Solid Waste or Incinerated
Residue, " Proc. 1968 Nat. Incinerator Conf., New York, 5-8
May 1968, pp 242-48.
Slatin, B., "Paper and Paperboard Consumption - Trends to
1980, " presented to the ASME~ Incinerator Div., New York,
14 Nov. 1968. .
";3olid Wastes Study of a Residential Area," USPHS, Solid
Wastes Program, Cincinnati, October 1966.
"Kalamazoo County Road Commission, Solid Wastes Study,"
USPHS, Solid Wastes Program, Cincinnati, 1967.
"Solid Wastes Study and Planning Grant, Jefferson County,
Kentucky," USPHS, Solid Wastes Program, Cincinnati, 1967.
174. ,11 The Solid Waste Disposal Study, Genesee County, Michigan, 11
USPHS, Solid Waste Program, Cincinnati, 1968.
175.
1 76.
"Comprehensive Solid Waste Study:' Johnson City, Tennessee,"
USPHS, Solid Wastes Program, Cincinnati, May 1968.
Watson, R. H., and Burnett, J. M., "Municipal Refuse as a
Fuel," Proc. Inst. Mech. Eng., 183, Part 1 (24), 519-26
(1968-69).
D-15
-------
VI.
AIR POLLUTION ASPECTS
1 77.
1 78.
1 79.
180.
181.
182.
183.
184.
185.
186.
187.
Andritzky, M.,"(Constructionand Tests of the Flue Gas Dust-
Removal Unit in the Munich Incinerator Plant North I)," Brenn-
stoff-W~rme-Kraft, 19 (9), 436-9 (1967).
Barton, A. E., and Ostle, E. J.. II Tests on Emission from
Refuse Incinerator Stacks," Smokeless Air, 37, 159-60 (1967).
Bump, R. L., "The Use of Electrostatic Precipitators for In-
cinerator Gas Cleaning in Europe, "Proc. 1966 Nat. Incinerator
Conf., New York, 1-4 May 1966. pp 161-6.
Bump, R. L., "The Use of Electrostatic Precipitators on Muni-
cipal Incinerators," J. Air Poll. Control Assoc., ~ (12), 803-9
(1968).
Burck1e, J. 0., Dorsey, J. A., and Riley, B. T., "The Effects
of the Operating Variables and Refuse Types on the Emissions
from a Pilot-Scale Trench Incinerator, " Proc. 1968 Nat. In-
cinerator Conf., New York, 5-8 May 1968, pp 34-41.
Carotti, A. A., Smith, R. A., and Wikstrom, L., "Chemical
Composition of Stack Effluent from Municipal Incinerators, "
presented at the Eng. Found. Res. Con£., Solid Waste Research
and Development, Milwaukee, 24-8 July 1967.
Cederholm, C., "Collection of Dust from Refuse Incinerators in
Electrostatic Precipitators Provided with Multicyclone After-
Collectors, " Proc. Int. Clean Air Congres s, London, 4-7 Oct.
1966, Part 1, Paper V /3.
Cross, F. L., Jr., Drago, R. J., and Francis, H. E., "Metal
and Particulate Emissions from Incinerators Burning Sewage
Sludge and Mixed Refuse," Proc. 1970 Nat. Incinerator Conf. ,
Cincinnati, 17-20 May 1970, pp 189-95.
Ellison, W., "Control of Air and Water Pollution from Municipal
Incinerators with the Wet-Approach Venturi Scrubber," Proc.
1970 Nat. Incinerator Conf., Cincinnati, 17-20 May 1970, pp
157-66.
Feldman, M. M., "Particulate Emission Control for Municipal
Incinerators, " Proc. MECAR Symp. New Developments in Air
Pollution Control, New York, October 1967, pp 70 -3.
Fernandes, J. H., "Incinerator Air Pollution Control, 11 Proc.
1968 Nat. Incinerator Conf., New York, 5-8 May 1968, pp 101-16.
D-16
-------
188.
189.
190.
191.
192.
193.
194.
195.
196.
197.
198.
199.
Fife, J. A., and Boyer, R. H., Jr., "What Price Incineration
Air Pollution Control'? ," Proc. 1966 Nat. Incinerator Conf. ,
New York, 1-4 May 1966, pp 89-96.
Fife, J. A., "Control of Air Pollution from Municipal Incine-
rators," Proc. 3rd Nat. Con£. on Air Pollution, Washington,
D. C., 12-14 Dec. 1966, pp 317-326. .
Fitzpatrick, J. V., "Solid Refuse Disposal Practices as Related
to Air Pollution Problems, II Proc. 3rd Nat. Con£. on Air Pollution,
Washington, D. C., 12-14 Dec. 1966, pp281-284.
Flood, L. P., "Air Pollution from Incinerators - Causes and
Cures," Civil Eng., ~ (12), 44-8 (1965).
Hangebrauck, R. P., von Lehmden, D. J., and Meeker, J. E.,
"Emissions of Polynuclear Hydrocarbons and Other Pollutants
from Heat-Generation and Incineration Processes, 11 J. Air
Poll. Control Assoc., .!:.! (7), 268-278 (1964).
Hirayama, N., et aI, "(Study of the Refuse Incinerator from the
Viewpoint of Sm()"KeCharacteristics), " Bull., Japan Soc. Mech.
Engineers, .!..!. (47), 902-12 (1968).
Hishida; K., "(Explanation of and Guidelines for a Collection
System for Refuse Incinerator Smoke)," J. Poll. Control (Japan),
~ (6), 365-72 (1967).
Jens, W., and Rehm, F. R., "Municipal Incineration and Air
Pollution Control," Proc. 1966 Nat. Incinerator Conf., New
York, 1-4 May 1966, pp 74-83. .
Johnson, H. C., Ping, A., and Clayton, L., "Emissions and
Performance Characteristics of Various Incinerators," presented
at 57th Annual Air Pollution Control Assoc. Meeting, Houston,
21 -25 June 1964. '
Kaiser,E. R., "Prospects for Reducing Particulate Emissions
from Large Incinerators," J. Air Poll. Control Assoc., 16 (6),
324 (1966); Combustion, ~ (2), 27-9 (1966). -
Kaiser, E. R., "The Sulfur Balance of Incinerators, " J. Air
Poll. Control Assoc., .!.! (3), 171-4 (1968).
Kalkhoff, A. W., "Incineration vs Air Pollution - A Necessary
Divorce," Proc. 1966 Nat. Incinerator Con£. , New York, 1-4
May 1966, pp 60-3.
D-17
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200.
201.
202.
203.
204.
205.
206.
207.
208.
209.
210.
211.
212.
Kurker, C., "Reducing Emissions from Refuse Disposal," J. Air
Poll. Control As soc., 19 (2), 69-72 (1969).
LaRue, P. G., "Pollution-Controlled Gas Incine ration: A Solution
to the Growing Problem of Solid Waste Disposal, " ASHRAE J J 12
(2), 58-62 (1970). .
Leib, H., "(Dust Removal and Composition of Flue Gases in the
Industrial Waste Incineration Plant of BAS F) , 11 Mitteilungen der
VGB, 93, 434-37 (1964).
--
Niessen, W. R., "Systems Study of Air Pollution from Municipal
Incineration, " A. D. Little Co. Report to the NAPCA on Contract
No. CPA-22-69-23, March 1970.
Niessen, W. R., and Sarofim, A. F., 11Incinerator Air Pollution:
Facts and Speculation, "Proc. 1970 Nat. Incinerator Conf., Cin-
cinnati, 17-20 May 1970, pp 167-181.
Ochs, H. J., "( The Use of Air Filters in Refuse Incineration
Plants)," Wasser, Luft, und Betrieb, ~ (9), 535-37 (1964).
Pascual, S. J., and Pieratti, A., "Fly-Ash Control Equipment
for Municipal Incinerators, " Proc. 1964 Nat. Incinerator Coni. ,
New York, 18-20 May 1964, pp 118-25.
Rathgeber, F., "(Removal of Dust from the Flue Gas from Waste
and Re.fuse Incineration)," Wasser, Luft, und Betrieb, 13 (2),
46-50 (1969). -
Rehm, F. R., "Control of Air Pollution from Municipal Incine-
rators, " presented at the Nat. Con£. on Air Poll., Washington,
D. C., Dec. 1966.
Rogus, C. A., "Control of Air Pollution and Waste Heat Recovery
from Incineration," Public Works, 97 (6), 100-5 (1966).
Rohr, F. W., "Suppression of the Steam Plume from Incinerator
Stacks, " Proc. 1968 Nat. Incinerator Con£., New York, 5-8 May
1968, pp216-24.
Scharfenstein, O. H. C., "(PVC-Waste Incineration - City
Health Officials Give Information), 11 StM.dtehygiene, 20 (8),
192-96 (1969). -
Schiemann, G., "(Results of Emission Measurements from
"
Community Incinerators), II Brennstoff- Warme -Kraft, 19 (9),
440-443 (1967). -
D-18
-------
213.
214.
215.
216.
217.
f "':. '.~. : ':. '. \ . .'.'
','.
, "
.' '.: -.
'j",
, Schwarz, ,K., "(Measures Taken in Incineration Plants to Prevent
Pollution), 11 Proc. 3rd International Congr. on Treatment and Dis-
posa1 of Refuse and Sewage Sludge, Trento (Italy), 24-29 May 1965,
p 120.
Smith, R. A., Hornyak, J., and Carotti, A. A., "Analysis of
Stack Effluent from Municipal Incinerators, " presented at the
Eng. Found. Res. Con£., Solid Waste Research and Development,
Milwaukee, 24-28 July 1967.
Stenburg, R. L., et aI, "Field Evaluation of Combustion Air Ef-
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J. Air Poll. Control Assoc., 12 (2), 83-9(1962).,
Stenburg, R. L., et aI, "Effects of Design and Fuel Moisture on
Incinerator Effluents," J. -Air Poll. Control Assoc., 10, 114-20
(1966).
Teller, W., and Bohne, H., "(Hydro~en Chloride in Flue Gases
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28-9 (1969). -
218. "Air Borne Emissions from Municipal Incinerators," USPHS,
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219.
220.
"A Technical Services Report on an Environmental Evaluation
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Wastes Program, July 1968.
"Preliminary Report for a Technical Services Environmental
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221. ' Velzy, 0., "Air Pollution Control for Refuse Incinerators - A
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222.
223.
224.
Walker, A. B., "Electrostatic Fly-Ash Precipitation for Muni-
cipal Incinerators - A Pilot Plant Study, " Proc. 1964 Nat. In-
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Walker, A. B., and Schmitz, F. W., "Characteristics of Furnace
Emissions from Large, Mechanically-Stoked Municipal Incine-
rators, "Proc. 1966, Nat. Incinerator Conf., New York, 1-4 May
1966,pp 64-73.
Weber, E., "( The Amount of Dust and Flue Gas from a Refuse
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D-19
-------
VII.
225.
226.
Wegman, L. S., "An Incinerator with Rcfrqctory Furnaces and
Advanced Stack Gas Cleaning Systems," Pruc. MECAR Symp.,
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Whitehead, C., and Darby, K., "Cleaning of Gases from the
Incineration of Waste Materials," presented at the Incineration
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RELATED THERMAL PROCESSES
227.
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231.
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Bailie, R. C., "Solid Waste Incineration in Fluidized Beds,"
presented at the Eng. Found. Res. Con£., Solid Waste Research
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Bailie, R. C., Donner, P. M., and Galli, A. F., "Potential
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Incinerator Con£., New York, 5 -8 May 1968, pp 12 -1 7.
Blanc, H., and Maulaz, M., "Sludge Press Cake Incineration
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"CPU -400 Year 2 Final Report, 11 Combust~on Power Co. Report
to the USPBS on Contract CPE 69 -1 00, July ~ 969.
Corey, R. C., IIResearch in the Bureau of Mines on the Pyrolysis
of Solid Wastes, " presented to the ASME, Incinerator Division,
Research Technical Committe~, New York, 14 May 1969.
Eberhardt, H., and Weiand, H., "(Experiences with the Novel
Tilting -Stage Garba~,'~ .Incineration Met~od at the Co~posting
Plant at Stuttgart-;Mormgen), " Aufberelt~ngs - Techlllk, 11,
490-94(1962.). ... -
Hanway, J. E., "Fluidized Bed Processes - A Solution for In-
dustrial Waste Problems," presented at the 22nd Purdue Ind.
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Hescheles, C. A., II Ultimate Disposal of Indust:rial Wastes, II
Proc. 1970 Nat. Incinerator Con£. , Cincinnati, 17-20 May 1970,
pp 235 -43.
Hoffman, D. A" and Fitz, R. A., "Pyrolysis of Solid Municipal
Waste, " presente!i at: the Eng. Found, Res. Cop.f., Solid Waste
Research and Development, Milwaukee, 24-28 July 1967; also
see Envir. Sci. & Tech., ~ (11), 1023-6 (1968).
D-20
-------
236.
237.
238.
239.
240.
241.
242.
243.
244.
245.
246.
Kaiser, E. R., and Friedman, S. B., "Pyrolysis of Municipal
Refuse, " presented at the Eng. Found. Res. Conf., Solid Waste
Research and Development, Milwaukee, 24-28 July 1967; also
see Symp. Air Poll. Control through Applied Combustion Science,
60th Annual Meeting AIChE, New York, 26-30 Nov. 1967; and
Combustion, 39 (11), 31-6 (1968).
Kaiser, E. R., "Evaluation of the Melt-Zit High Temperature
. Incinerator, Operation Test Report, Aug. 1968," Report to the
City of Brocton, Mass., on USPHS Grant'No. DOI-UI-00076,
1969.
Kaupert, W., "(Refuse Gasification - Experience Obtained in the
Refuse Gasification Plant of Kolding, Denmark), II Brennstoff-
W~rme-Kraft, 20 (9), 433-35 (1968).
Kaupert, W., "(Refuse Gasification. Research and Experience
in the United States) I" Warme, 75 (2/3), 48 -50 (1969).
Kennedy, J. C., "Current Concepts in the Disposal of Solid
Wastes," J. Envir. Health, ~ (2), 149-52 (1968).
Mihm, V., "The FLK Slagging Incinerator - A New Design Con-
cept, " presented to the ASME, Incinerator Division, Design
Committee, 13 March 1969.
Millward, R. S., and Darby, W. A., "Fluidized Bed Combustion,"
presented at the 13th Annual Waste Eng. Con£., Minneapolis,
10 Dec. 1966.
Reh, L., "(Combustion and Thermal Destruction of Industrial
Wastes in the Liquid or Sludge Forms), II Chemie-Ing. -Techn.,
~ (4), 165-71 (1967). .
Reynolds, W. F., "The Bureau of Mines Looks at Refuse Dis-
posal and Recovery Possibilities," Public Works, 99 (12), 85-6
(1968). -
Sanner, W. S., et aI, "Conversion of Municipal and Industrial
Refuse into Useful Materials by Pyrolysis, " Bureau of Mines
Report 7428, 1970.
Shuster, W. W., and Gilbert, J. S., "Partial Combustion of
Solid Organic Wastes," presented at the Eng. Found. Res.
Con£. , Solid Waste Research and Development, Milwaukee,
24-28 July 1967.
D-21
-------
VIII.
247.
248.
249.
250.
251.
Smith, R. D., "Feasibility Study of Applying Jet-Engine Tech-
nology to Incineration, " presented at the Eng. Found. Res.
Conf., Solid Waste Research and Development, Milwaukee,
24-28 July 1967.
"Combustion Power Unit-400," USPHS, Bureau of Solid Waste
Management, 1969.
"Comprehensive Studies of Solid Waste Management, 2nd Annual
Report, " University of California Berkeley, Sanitary Engineering
Research Lab., Rep9rt No. 69 -1, Jan. 1969.
Velzy, C. R., "Potentials in Incineration," ASME Publ. 65-
WA/PID-IO.
Zinn, R. E., LaMantia, C. R., and Niessen, W. R., "Total
Incineration, " Proc. 1970 Nat. Incine rator Con£., Cincinnati,
17-20 May 1970, pp 116-127; Ind. Water Eng., 7 (7), 29-34,
(1970). -
RELATED WASTE HANDLING PROCESSES
252.
253.
254.
255.
256.
257.
258.
259.
Andreas, E., "Grinding Harbour and Bulky Refuse in Amsterdam, II
Int. Res. Group on Refuse Disposal, Bull. 18, Aug. 1963, pp 48-9.
"
Anon., "(Trash Preparation with the Gorator}," Brennstoff-Warme-
Kraft, ~ (8), 404-5 (1964).
Boettcher, R. A., "Air Classification for Reclamation Processing
of Solid Wastes," ASME Pub!. 69-WA/PID-9.
Brown, R. R., and Block, F. E., "Copper Removal from Steel
Scrap by Thermal Treatment," Bureau of Mines Pub!. RI-7218,
Dec. 1968. '
Cerniglia, V. J., "Close-Circuit Television and its Application
in Municipal Incineration, II Proc. Nat. Incinerator Con£., New
York, 1-4 May 1966, pp 187-90.
Elger, G. W., Hunter, W. L., and Arrpantrout, C. E., "Re-
moval of Nonferrous Metals from Synthetic Auto Scrap by Heating, "
Bureau of Mines Pub!. RI-72l0, Dec. 1968.
Engdahl, R. B., "Solid Waste Processing - A State-of-the-Art
Report on Unit Operations and Processes, II USPHS, Bureau of
Solid Waste Management Report SW -4C, 1969.
Harding, C. J., "Recycling and Utilization," the Surgeon General's
Conference on Solid Waste Management for Metropolitan Washington,
19-20 July 1967, USPHS Pub!. 1729, 1967, pp 105-119.
D,..22
-------
260.
261.
262.
263.
264.
265.
266.
267.
268.
269.
270.
271.
272.
,..- . ~
Heiny, B., "(Waste Incinerator Equipment for Solid and Liquid
"
Refuse in the Volkswagenwerk Wolfsburg)," Brennstoff- Warme-
Kraft, 20 (5), 212-14 (1968).
Hershaft, A., "Solid Waste Treatment, II Sci. & Tech., 68,
34-42 (1969).
King, J. A., and Archer, G. A., "Refuse Pulverizing Plant,
Slough," Public Cleansing, pp 232-50, May 1970.
Kummer, F., "A New Machine for Grinding Bulky Refuse,"
Int. Res. Group on Refuse Disposal, Bull. 20, May 1964,
pp 56-59.
Meyer, A. F., "Grinding, an Aid in Refuse Disposal, " Public
Works, 97, 156 (1966).
Patrick, P. K., "Waste Volume Reduction by Pulverisation,
C rushing and Shearing, 11 Institute of Public Cleansing 69th
Annual Conference, Blackpool (England), 9 June 1967, p. 39.
Pikarsky, M., "Chicago Looks to Refuse Grinding, II Public
Works, 101 (9), 82-3 (1970).
Rampacek, C., "Extraction of Metal and Mineral Values from
Municipal Incinerator Residues - A Progress Report," pre-
sented at the Eng. Found. Res. Con£. , Solid Waste Research
and Development, Milwaukee, 24-28 July 1967; also see Proc.
Symp. Mineral Waste Utilization, 27-8March 1968, pp 124-31.
Randles, L. C., Jr., "The Field of Refuse Salvage," Compost
Science, 4 (2), 5-10 (1963).
Reinhardt, J. J. J "A Report on Milled Refuse and the Use of
Milled Refuse in Landfill, " City of Madison, Division of En-
gineering, Bulletin GR-69124, 20 Jan. 1969.
Snyder, M. J., et aI, "Fly Ash Utilization Research Program, "
Edison Elec. Inst. Bull., pp 38-42, Feb. 1966.
Steward, G. H., and Grant, R. M., "The Handling of Waste
Materials," 'presented at the Incineration Con£. , Inst. of Fuels,
Brighton (England), 25 -26 Nov. 1969.
Tanzer, E. K., "Pneumatic Conveying for Incineration of Paper
Trim," Proc. 1968 Nat. Incinerator Con£. , New York, 5-8 May
1968, pp 309-17.
D-23
-------
273.
274.
275.
276.
Vaughan, R. D., "Reuse of Solid Wastes: A Major Solution to
a Major National Problem, II Waste Age, .!.. (1), 10 and ff (1970).
Wiley, J. S., "Some Specialized Equipment Used in European
Compost Systems, " Int. Res. Group on Refuse Disposal, Bull.
18, Aug. 1963, pp 25-33; Compost Science, 4 (1) 7-10 (1963).
Wilson, D. G., and Smith, D. E., "Mechanized Reclamation
from Municipal Solid Waste," presented at the Nat. Ind. Solid
Waste Conf., Houston, March 1970.
Zandi, 1., and Hayden, J. A., "The Flow Properties of Solid
Waste Slurries, " presented to International Conf. on Hydraulic
Transport of Solids in Pipes, London, 1-3 Sept. 1970; also see:
Envir. Sci. & Tech., ~(9), 812-19 (1969).
D-24
-------
IX.
AUTHOR INDEX
Abrahams, J. H., 139
Andreas, E., 252
. Andritzky, M., 1, 2, 177
Angenend, J., 3, 111
Ariey, A. F., 81, 82
Bachl, H., 5, 6, 7
Bailie, R. C., 227, 228
Barton, A. E., 1 78
Bauer, H., 8
Bell, J. M., 140, 149, 150
Beningson, . H. E., 9
Beningson, R. M., 9
Black, R. J., 141
Blanc, H., 229
Block, F. E., 255
Boettcher, R. A., 254
Bohne, H., 217
Bowen, I. G., 129
Boyer, R. H., Jr., 188
Braun, R., 130
Brealey, L. 129
Britton, P. W.,. 164
Brown, R. R., 255
Bryers, R. W., 112
Bump, R. K., 179, 180
Bunde, H., 48
Burck1e, J. 0.; 181
Burnett, J. M., 1 76
Calhoun, J. C., Jr., 142
Canon, C. N., 10
Carotti, A. A., 182, 214
Carruth, D. E., 144
Cederholm, C., 183
Cerniglia, V. J., 256
Chansky, S. H., 165
Cheney, R. L., 139
Clayton, L., 196
Cohan, L. J., 11, 131, 145
Connell, J. M., 12, 13
Corey, R. C., 231
Cross, F. L., Jr., 184
Darby, K., 226
Darnay,A., 147
Defeche, J., Jr., 113
Deming, L. F., 13, 66
Diamant, R. M. E., 14, 15
Donner, P. M., 228
Dorsey, J. A., 181
Drago, R. J., 184
Drewes, W., 110
Dvirka, M., 16
Eberhardt, H., 16, 17, 232
Eckhardt, F., 18
Elger, G. W., 257
Elias s en, R., 148
Ellison, W., 185
Engdahl, R. B., 19, 258
Engel, W., 20
Etzel, J. E., 149, 150
"
Fassler, K., 114
Feldman, M. M., 186
Fe rnande s, J. H., 11, 145
Fichtner, W., 21
Fife, J. A., 22, 188, 189
Fink, F., 115
Fitz, R. A., 235
Fitzpatrick, J. V., 190
Flood, L. P., 191
Forbert, G., 23
Foster, W. S., 151
Francia, F. P., 157
Francis, H. E., 184
Franklin, W. E., 147
Fulmer, M. E., 152
Galli, A. F., 228
Gampper, R., 24
Garretson, B. B., 81, 82
Geer, G. L., 8, 25, 26
Gerhardt, P., Jr., 27
Gilbert, J. S., 246
Goepfert, J., 28, 29
Golueke, C. G., 153
Grant, R. M., 271
Green, B. L., 30
D-25
-------
11
Hafeli, R. J., 154
Hamm, H. W., 155
Hammer1ei, H., 31
Hampton, R. K., 132
Hangebrauck, R. P., 192
Hansen, E. G., 32
Hanway, J. R., 233
Harding, C. J., 259
Hart, S. A., 33
Hawkins, G. A., 133
Hayden, J. A., 276
Heiny, B., 260
Hershaft, A., 261
Hescheles, C. A., 234
Hickman, H. J., Jr., 156
Hilsheimer, H., 34
Hirayama, N., 193
Hirsch, M., 116, 11 7
Hishida, K., 194
Hitchcock, C. Y., 35
Hoffman, D. A., 235
Hornyak, J., 214
Hotti, G., 36, 37
Howard, J. B., 38
Huch, R., 118
Hummell, J. D., 19
Ingram, W. T., 157
Jacobi, J. M., 106
Jens, W., 195
Jensen, M. E., 39
Jesson, H. E., 40
Johnson, H. C., 196
Kachulle, C., 41
Kaiser, E. R., 134,
160,
197,
237
Kalika, P. W., 42
Kalkhoff, A. W., 199
Kallenbach, K., 43
Kammerer, H. F., 44
Kasner, D., 162
Kaupert, W., 45, 238, 239
Kenahan, C. B., 135
158, 159,
161, 162,
198, 236,
Kennedy, J. C., 163, 240
Kerekes, Z., 112
Kern, A., 46
King, J. A., 262
Klee, A. J., 144, 164
Knoll, H., 47
K8hle, H., 119
11
Korbel, W., 59
Kummer, F., 263
Kurker, C., 200
Kutzschbauch, K., 48
LaMantia, C. R., 251
LaRue, P. G., 201
Lauer, H., 49
Leib, H., 114, 202
Lieberg, O. S., 50
Lorenzini, R. A., 51
Maikranz, F., 5, 52, 53
Maulaz, M., 229
Ma ye r, W., 1 7
McCaffery, J. B., 134
McKenzie, E. C., 54
Meeker, J. E., 192
Meyer, A. F., 264
Michna, L., 8
Mihm, V., 241
Millward, R. S., 242
Moegling, E., 55
Moore, H. C., 56, 57
M~rch, 0., 58
Muhich, A. J., 164
Mullen, J. F., 72
Mutke, R., 59
Nickerson, R. D., 72
Niessen, W. R., 165, 203,
204, 251
Nowak, F., 60, 61, 120, 121
Nuber, K., 62
Ochs, H. J., 205
Ostle, E. J., 178
D-26
-------
Palm, R., 63
Pascual, S. J., 206
Patrick, P. K., 265
Pep~, P. D., 64
Perl, K., 65, 122
Pieratti, A., 206
Pikarsky, M., 266
Ping, A., 196
Pope, M., 66
Porteous, A., 67
Presuhn, A., 68
Purdom, P. W., 137,
138, 169
Rampacek, C., 267
Randles, L. C., Jr., 268
Rasch, R., 69, 70, 71, 117,
123, 124, 125
Rathgeber, F., 207
Reardon, F. X., 56
Regan, J. WoJ 72, 73
Reh, L., 243
Rehm, F. R., 195, 208
Reimer, H., 28
Reinhardt, J. J.., 269
Reynolds, W. F., 244
Riley, B. T., 181
Roberts, J., 132
Rogus, A., 74, 75, 76, 166,
167, 209
Rohr, F. W., 210
Rolfe, T. J. K., 40, 77
Rousseau, H., 32, 78
Russ, H., 168
Rutz, P., 79
Salamon, 0., 95
Sanner, W. S., 245
Sarofim, A. F., 204
Scharfenstein, O. H. C., 211
Schenkel, W., 80
Schiemann, G., 212
Schmitz, F. W., 223
Schoenberger, R. J., 138, 169
Schwartz, K., 213
Scott, D. H., 54
Sebastien, F. P., 81, 82
D-27
Seibel, J. E., 42
Shequine, E. R., 83
SherI, G. A., 84, 85
Shuster, W. W., 246
Slatin, B., 1 70
Smith, D. E., 275
Smith, R. A., 182, 214
Smith, R. D., 247
Snyder, M. J., 270
Sommerlad, R. E., 86, 126
"
Spahn, H., 114
Spitzer, P. E., 87
Stabenow, G., 88, 89
Steller, P., 59, 127
Stenburg, R. L., 215, 216
Stephenson, J. W., 90
Steward, G. H., 271
Sutin, G. L., 91, 92
Tanner, R., 37, 93,
Tanzer, E. K., 272
Teller, W., 21 7
Testin, R. F., 152
Trieff, N. M., 169
Turner, G. M., 64
94, 95
van der Kooi, 1., 98
Vaughan, R. D., 273
Velzy, C. R., 99, 250
Velzy, 0., 99, 221
von Lehmden, D. J., 192
von Weihe, A., 20, 100
Walker, A. B., 222, 223
Wangerin, D. D., 101
Watson, R. H., 1 76
Weber, E., 224
Wegman, L. S., 225
Weiand, H., 232
Whitehead, C., 226
Wiley, J. S., 274
Wilson, D. G., 275
Winkens, H. P., 102, 103, 104
Wisely, F. E., 105
Wolf, M. 106
Wuhrmann, K. A., 107, 108
-------
Zandi, 1., 276
Zanft, A. B., 15
Zank1, W., 109
Zeit, C. D., 134
Ziemer, G., 110
Zimmer, C., 162
Zinn, R. E., 251
D-28
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APPENDIX E
GLOSSAR Y
-------
APPENDIX E - GLOSSARY
Air -
Theoretical or stoichiometric - the quantity of air required to oxidize
all of the labile constituents in a unit weight of fuel to C02 and
H20. ..
Exces s - the quantity of air in exces s of theoretical employed in the
combustion process.
Combustion - theoretical plus excess air. The terms primary-,
secondary-, and tertiary-air are also used. These terms,
derived from pulverized coal firing, relate to the air-flow
arrangements up to and with respect to the burner.
Underfire - the combustion air introduced under a grate to promote
burning within the fuel bed.
Overfire - the combustion air introduced over a grate to promote
combustion of the gases rising from the fuel bed.
Air Heater - A device for transferring some of the residual heat in the ex-
haust flue gas to the intake air passing into the furnace to support
combustion. The recuperative and regenerative types are the best
known generic forms. .
Annualization - The annual apportionment required to recover all capital
related costs, such as interest, amortization, insurance, and taxes.
APC - Air pollution control.
Bag House - An air pollution control device consisting of a system of fabric
filter envelopes through which flue gas is pas sed to remove dust.
Boiler Surface - That portion of the boiler working -fluid circuitry in which
water undergoes change of state; i. e., boiling occurs.
Calorific Value - See Heating Value.
CAMP - Continuous Air Monitoring Program.
Capital Recovery Factor - The annual percentage that is required to
tize the capital debt at some given rate of return for a definite
period.
amor -
time
Clinker - A solidified slag deposit found in a boiler.
E-l
-------
ConvcctirJn Section -That portion of the boiler in which the exchange of heat
through boiler surfaces occurs directly between the flue gas and the
working fluid. Thus, those sections which ~re obstructed from the
flame and do not undergo radiant heat transfer.
Critical Pressure - A characteristic partial pressure of a substance at which
liquefaction can occur when the substance is at critical temperature.
Critical Temperature - A characteristic temperature of a substance above
which liquefaction cannot occur, regardles s of its partial pres sure.
The substance is then said to be a gas rather than a vapor.
Demister - A device for removing liquid droplets entrained in flue gases.
Disposal Cost - In the present report, this is an inside battery limits
cost term that includes aU plant costs for reducing refuse to an
inert residue and effecting the ultimate disposal of the latter.
Refuse transportation costs (q. v. ) and power transmission are
necessarily excluded from disposal cost.
Downcomer - A member of a steam circuit, usually unheated, which permits
the working fluid to flow as a liquid, usually saturated, down to a dis-
tribution point from which it can then rise through boiler tubes within
the furnace.
Duty - The energy content of the steam produced per unit time by a boiler.
Usually expressed as 109 Btu/hr.
Economizer - The first stage of the boiler where the working fluid is heated
by exiting flue gas. Typically, feed water is fed back through the eco-
nOlnizer and then pas sed to the primary boiler steam circuits.
Efficiency (Combined Steam Generator) - The percent of the input fuel energy
transferred to the output working fluid.
Electrostatic Precipitator - An air pollution device consisting of an array of
electrodes through which the flue gas flows. The high voltage cathodes
operate at corona condition and induce some ionization of the flue gas.
Collisions between negative ions and particles charge the latter with
surface electrons and cause migration to the grounded anodes. There
discharge occurs and the collected dust can be mechanically dislodged
into hoppers.
Enthalpy - The heat content of a system; usually expressed as the sum. of the
internal energy (sensible and latE;nt heats) and the work content implicit
in the pressure-volume condition.
Feedwater Heater - A heat exchange system for heating the working fluid
recovered in the condenser to desired economizer inlet conditions.
The energy for this process is often supplied by steam tapped from
the turbine. .
Fireside - Loosely, that portion of boiler heat exchange structures exposed
to hot combustion gases (as opposed to steam side).
E-2
-------
Forced Circulation - Boiler circuitry in which movement of the wo rking fluid
frorn the drum through downcomers, up boiler tubes, and back to the
steam drum. is promoted by pumps.
Fossil Fuel - Any material capable of supporting combustion that has been
formed by the long -term effects of subterranean environments on an-
cient vegetable deposit!). Included are such fuels. as coal (anthracitic,
bituminous, lignitic), oil, natural gas, 'and by-products thereof, as
well as certain less fossilized materials.
Fuel Value - See Heating Value.
Grate - Device for supporting coarse fuels stoked into furnaces. Agitating
grates are inclined, the steps of which can move in either a rolling or
reciprocating manner. Travelling grates are endless-belt conveyors
(non-agitating) and are usually horizontal. Retainer grates are sta-
tionary devices situated in the hopper area to catch burning fall-out
from material fired in suspension.
Heat Capacity - The quantity of heat required to increase the temperature
of a unit weight of substance 1 degree in the absence of frictional and
change of state processes. In the English system, the Btu is defined
as the quantity of heat required to cause a temperature rise of lOF in
1 lb of water from 39. lOF (maximum density temperature).
Heat Rate (Net Plant) - The heat from fuel that must be supplied to produce
a unit of power. This tern~ is usually expressed as Btu/kw-hr.
Heating (or Heat Value) - The thermal energy released per unit weight of
fuel (Btu/lb or cal/g) undergoing combustion. In the U. S., the higher
heating value (HHV) is used. This corresponds with calorimetric
measurement, in that water vapor formed during combustion is con-
sidered to u,ndergo condensation. In Europe, the lower heating value
(LHV) is commonly used. This term, usually calculated from the
calorimetric value or HHV, requires that the water formed by the
oxidation of bound hydrogen in the fuel does not undergo condensation
after the combustion proces s has occurred.
Liquid (or Wet) Scrubber - Any air pollution control device that brings the
flue gas into intimate contact with a liquid phase to effect contaminant
removal. The process can proceed by th.e acquisition of liquid on par-
ticles in the flue gas to render them susceptible to subsequent removal
in mechanical collectors or by the entraprnent of solids within or the
solution of gase~ into the liquid phase.
LMA - Large Metropolitan Area.
E-3
I
-------
Mechanical Dust Collector - Any inertial air pollution control device which
traps out particulates by centrifugal force. The latter effect is im-
parted by the gas stream itself, which is made to flow in a cyclonic,
or related, manner within the collector.
Nameplate Rating - The nominal power capacity of a turboele~tric sys.t~m
specified in the construction contract for normal operatIng condltIons.
Because of design margins, actual capacity is usually greater.
Net Disposal Cost - See Disposal Gos-t.
Net Total Disposal Cost - The sum of disposal and transportation costs.
NASN - National Air Sampling Network.
Natural Circulation - Boiler circuitry in which movement of the working fluid
from the drum through downcomers, up boiler tubes, and back to the.
steam drum is promoted by convection within the liquid phase.
Once
Through - Boiler circuitry in which the working fluid does
as a liquid via a drum, but is completely volatilized in its
through the radiant section of the boiler.
not circulate
first pass
Pendant Section - A continuous tube run in a panel-like arrangement, the
inlet and outlet ends of which are supported by headers. The section
thus hangs from the latter.
Plant Factor - The ratio of the average electrical load to the rated capacity
for a given time period.
Platen Section - A continuous tube arrangement, the vertical members of
which are set very closely together. Each panel-like section is placed
in-line with respect to gas flow and 9 to l2-in. apart from other platen
sections arranged in parallel. The purpose of a platen superheater is
to drop the temperature of the flue gas so that slagging and fouling on
more closely grouped tube banks downstream will be minimized.
Radiant Section - That portion of the boiler in which the transfer of heat to
the working fluid can occur by the absorption of radiant energy emitted
by the flame.
Rankine Cycle - A hypothetical cycle of a steam generator in which all heat
transfers take place at constant pressure and in which expansion and
compres sion effects are produced adiabatically.
Reheat - A process wherein turbine exhaust steam, usually from the first
stage, is passed back through isolated heat exchange surfaces (re-
heaters) in the furnace to regain some of the energy transferred to
the turbine. The reheated steam is then introduced at a lower stage
of the turbine.
E-4
-------
. " :~~.
Retrofit - An operation wherein an existing device or system is modified
through the addition of new components so as to make it function in
an improved or different manner.
Saturation - When a liquid and its vapor are in equilibrium, each phase
is said to be saturated. For every temperature below the critical
temperature, there is a discrete pressure at which saturation
(equilibrium) can exist.
Sensible Heat - Heat which has been absorbed to produce a change in tem-
perature due to the heat capacity of the substance, as contrasted to
energy (latent heat) contributing to change of state processes.
Shot
Cleaning - A process wherein large steel shot (1/4- to 1/2-in. dia.)
is distributed, usually by gravity, down through convective passes
to dislodge ash accumulations. The shot is recovered and reused.
Slag - Molten ash.
Slag-Tap (or Slagging) Furnace - See Wet Bottom Furnace.
SMSA - Standard Metropolitan Statistical Area.
Soot Blower - A device situated in various portions of a boiler for directing
jets of stearn or air onto tube banks to dislodge ash accumulations.
Specific Heat - See Heat Capacity.
Spreader-Stoker - A firing arrangement wherein a coarsely divided fuel is
fed into the furnace by a suitable conveyance system and is blown up-
ward into the furnace by air jets. The falling, ignited fuel then falls
onto a horizontal grate to be burnt out and disposed of. The grate
typically used is of the travelling (endless belt) type.
Steamside - That portion of the heat exchange surfaces which are in con-
tact with the working fluid, regardless of which phase is present.
Superheat - A furnace proces s wherein saturated stearn from the boiler is
increased in temperature, enthalpy, and specific volume to required
outlet conditions. Superheater surfaces may be located in both the
raqiant and convective zones of the stearn generator. By superheating
stearn, a thermodynamic gain in the Rankine cycle results.
Suspension Firing - The process in which a solid fuel, usually of reduced
particle size, is injected into the mid-zone of the furnace so that it
will tend to burn out before settling.
Tipping - The unloading of refuse from a collection vehicle.
E-5
-------
Topsize - The specification for maximum particle length in any dimension
for coarse output from a hammermill or related grinding device.
Transportation Cost - The cost, exclusive of collection cost's, of transpor-
ting refuse, once trucks are loaded, to the disposal point.
TtJV
- Technische tTherwachungs Verein. A German organization involved
in the qualification and acceptance testing of steam generators and
various other hardware.
Tuyere - A furnace wall section containing a network of air nozzles. In the
present context, a system for delivering side-fire air to grates..
Venturi Scrubber - A wet scrubber in which the flue gas is accelerated
through a restriction or venturi to cause aerosolization of a scrubber
liquid injected into the venturi throat. Impaction of scrubber drop-
lets with dust particles renders the latter more susceptible to .
mechanical collection.
Wet Bottom Furnace - By virtue of its design and the fusion temperature of
the fuel used, a furnace which collects molten ash (slag) in its bottom.
The slag is periodically or continuously removed for quenching (solidi-
fication in water) through a suitable orifice (slag tap).
E-6
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