EPA-600/2-76-259
September 1976
Environmental Protection Technology Series
INITIAL ENVIRONMENTAL TEST PLAN FOR
SOURCE ASSESSMENT OF COAL GASIFICATION
Industrial Environmental Research Lateratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Caro!hia 27711
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Piotection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
er vironmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
Tills report has been reviewed by the U.S. Environmental
Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policy of the Agency, nor does mention of trade
mimes or commercial products constitute endorsement or
recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield. Virginia 22161.
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EPA-600/2-76-259
September 1976
INITIAL ENVIRONMENTAL TEST
PLAN FOR SOURCE ASSESSMENT
OF COAL GASIFICATION
by
A. Attari, M. Mensinger, arid J. Pau
Institute of Gas Technology
3424 South State Street
Chicago, niinois 60616
Contract No. 68-02-1307
ROAPNo. 21ADD-024
Program Element No. 1AB013
EPA Project Officer: William J. Rhodes
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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8943
ABSTRACT
Thi::: res earch effort has been directed toward the systematic develop-
ment of an environmental test plan to investigate the fate of a large number
of constituents and certain potentia!' pollutants of coal during gasification.
The test plan is a logical and well-conceived approach to the problems as so-
ciated wjth sampling point selection, sample collection, and sample analysis
for a con.plex and much needed proces s.
In accordance with the tasks outlined in the project proposal, the test
plan comprises 6 major sections.
The first contains a process flow sheet of a possible HYGAS-based coal
gasificat..on installation. Accompanying this flow sheet are three examples
of mater:.al balances calculated for a bituminous, subbltuminous 1 and a
lignite c(lal.
The second section contains the estimated material balances for 38
constituent elements as they might be distributed during gasification in a
typical commercial plant. Extensive thermodynamic calculations based on
chemical analyses have been performed in the development of these material
balances. Supporting discussions and the results of thermodynamic calcu-
lations are included in the appendixes.
The third report section assesses the effects of possible process upsets
on the dif:trlbution of the elements. A wide range of process operating con-
ditions afi evaluated by computer simulation indicate that moderate varia-
tions in t'~mperature and major variations in pressure do not significantly
change the expected trace-element distribution.
In th\~ fourth section, HYGAS pilot plant sampling locations are described
as well a:, methods of high pressure-high temperature gas, solid, and liquid
sampling"
The fifth section contains a list of suggested analytical methods to be
us ed in all actual testing program in support of a comprehensive environ-
mental study of coal gasification proces ses.
The last section
discusses the significance of the results of the analy-
tical methods as proposed herein.
ili
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8943
TABLE OF CONTENTS
HYGAS PROCESS DESCRIPTION
Page
1
1
Introduction
Coals
Coal Ash Materials
Pos sible Disposition of Trace and Minor Elements
Thermodynamically Stable Forms of the Elements in
HYGAS Process Units
Operating Regions
Pretreatment
Steam Plant
Hydrogasification
CO-Shift Reaction
16
16
19
20
23
23
Coal Pretreatment
Coal Energy and Moisture Content
Modes of Occurrence of Trace and Minor Elements in Coals
26
26
27
27
28
28
PROCESS STEPS
30
VARIABILITY OF OPERATING CONDITIONS
36
SAMPLING
41
Sampling Points
Sampling Techniques
Solid Samples
Liquid Samples
Gas eous Samples
41
44
44
44
45
ANALYTICAL METHODS
47
Solid Samples
Liquid Samples
Gas eous Samples
47
47
53
SIGNIFICANCE OF RESULTS
BIBLIOGRAPHY
62
69
APPENDIX A. Analyses of Synthane Water and Tar Samples
A-I
APPENDIX B. Sample Computer Output
B-1
iv
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APPENDIX C.
APPENDIX D.
APPENDIX E.
APPENDIX F.
APPENDIX G.
TABLE OF CONTENTS, Cont,
Flow-Rate Determination - Scaling Factors
Discussion of Process Units and Reactions
Presentation and Discussion of Thermodynamic
Calculations: Tables and Graphs
Example of Operating-Region Determination
Basis for Calculations
y
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Page
C-l
D-l
E-l
F-I
G-l
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Figure No.
1
2
E-1
E-2
E-3
E-4
E-5
E-6
E-7
E-8
E-9
E-10
E-11
E-12
E-13
E-14
E-15
LIST OF FIGURES
Process Flow Diagram for a Typical HYGAS-
Based Commercial Coal-Gasification Plant Design
Possible Distribution of Trace and Minor Elem~nts
Oxidation Reactions of Second-Period Sulfides to
Sulfites
Oxidation Reactions of Second-Period Sulfites to
Sulfates
Oxidation Reactions of Secoild-Period Nitrides and
Carbides to Oxides
Oxidation Reactions of Second-Period Chlorides and
Fluorides to Oxides
8943
Page
15
24
E-3
E-4
E-5
E-6
Carbonate-Forming Reactions of First-Period Oxides E-7
Carbonate-Forming Reactions of First-Period
Sulfide 1>
Carbonate-Forming Reactions of Second-Period
Oxides
Carbonate-Forming Reactions of Second-Period
Sulfides
Reduction Reactions of First-Period Sulfates to
Sulfites to Sulfides
Reduction Reactions of Second-Period Sulfates to
Sulfites to Sulfides
Sulfide Formation From First-Period Oxides
Sulfide Formation From Second-Period Oxides
Sulfide Formation From Second-Period Chlorides,
Fluorides, and Carbides
Formation of BeO From BeClz and First- and
Second- Period Oxides
Formation of MgO From MgClz and First- and
Second- Period Oxides
Vi
E-8
E-9
E-10
E-11
E-12
E-13
E-14
E-15
E-16
E-17
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Figure :~o.
E-16
E-17
E-18
E-19
, .
LIST OF FIGURES Cont.
Hydrolysis of Second-Period Nitrides to Oxide
and NH3 - Hydrogenation of Be3Nz to BeHz
Miscellaneous Reactions Involving KO(g)
Hydrogenation of Beryllium Compounds Forming
BeHz (g)
Miscellaneous Reactions of Antimony and Arsenic
Compounds
vii
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8943
Page
E-l8
E-19
E-20
E-21
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Table No.
1
2
3
4
5
6
7
8
9
10
11
12
13
LIST OF TABLES
Stream Compositions and Flow Rates for a HYGAS-
Based, Commercial Gasification Plant Using
Illinois No.6 Bituminous Coal and Producing 84.89
Nm~/ s SNG
Stream Compositions and Flow Rates for a HYGAS-
Based,~Commercial Gasification Plant Using.
Montari~ Subbituminous Coal and Producing 85.21
Nm3/s SNG
Stream Compositions and Flow Rates for a HYGAS-
Based, Commercial Gasification Plant Using Lignite
Coal and Producing 85.78 Nm3/s SNG
Calculated Flow Rates of Trace and Minor Elements
in a HYGAS-Based, Commercial Gasification Plant
Using Illinois No.6 Bituminous Coal
Typical Modes of Occurrence of Trace and Minor
Elements in Coal
Calculated Flow Rates of Trace and Minor Elements
in a HYGAS-Based, Commercial Gasification Plant
Using Montana Subbitu:m:inous Coal
Calculated Flow Rates of Trace and Minor Elements
in a HYGAS-Based, Commercial Gasification Plant
Using Montana Lignite
Computer-Calculated Gas Composition of HYGAS
Reactor Effluent for Various Temperatures and
Pressures
HYGAS Pilot Plant Sampling Points
Parameters Relating to Preservation, Ho]ding Time,
and Sample Storage
Analytical Methods for Chemical Analysis of Solid
Samples
Analytical Methods for Chemical Analysis of
Liquid Samples
Analytical Methods for Chemical Analysis of
Gaseous Samples
viii
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8943
Page
4
8
12
17
22
31
33
38
42
46
48
54
60
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Table :~o.
14
15
A-I
B-1
B-2
B-3
E-l
E-2
E-3
LIST OF TABLES Cont.
Summary of IGT Analytical Results for 38
Trace and Minor Elements in Feed and Residue
Samples of Two Coals Hydrogasified in a Bench-
Scale Unit
Analysis of NBS Standard Reference Materials at
IGT Laboratories
Water and Tar Analyses From Synthane
Gasification, mg /liter
Standard Operating Conditions
High-Temperature, High-Pres sure Operating
Conditions
High-Temperature, Low-Pressure Operating
Conditions
Calculated Values of Operating Regions
Thermodynamic Equilibrium Calculations of
log K With Temperature
eq
Thermodynamically Stable Forms of Elements in
the Proces s Units
lX
8943
Page
64
67
A-2
B-2
B-5
B-8
E-24
E-25
E-35
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8943
HYGAS PROCESS DESCRIPTION
Introduction
This study was initiated by the Environmental Protection Agency to
investigate the fate of trace elements of coal during the gasification proces s
for production of high-Btu pipeline-quality gas. The ultimate goal of the
investigation is to provide information that will enable the environmentally
sound operation of future commercial-scale coal-gasification plants.
In order to attain this goal, a test plan has been developed which pro-
vides a n estimated environmental impact of three examples of HYGAS-
bas ed coal-gasification facilities.
The test plan follows a logical program of investigation, which includes
examples of HYGAS proces s designs, followed by engineering estimates and
calculations (based on actual analytical data) of the possible distribution of
trace elements during gasification. Next, the test plah is oriented toward
the HYGAS pilot plant where a sampling program could be undertaken for
solid, liquid, and gaseous process streams. The suggested analyses of
pilot plant samples for trace elements and other species will provide im-
portant data on the high Btu-coal gasification processes and serve to refine
the distribution estimates which are presented in this report.
Instrumental to the successful completion of this test plan. was analy-
tical data obtained from the analysis of four series of coal feed. and residue
samples for the dete'rmination of 38 minor and trace elements.
The samples consisted of feed and solid residues of two separate
hydrogasification runs on Montana lignite plus the feed and solid residues
of two series of pretreatment and hydrogasification runs on Illinois No.6
bituminous coal, but included no gaseous or liquid samples.
1
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8943
Figure 1 is a block-flow diagram of a HYGAS-based, large coal-gasifi-
cation plant with an integrated steam-oxygen gasifier. This flow sheet, and
the n~lated material balances, depict only one of many possible variations
in the design of coal gasification facilities based on the HYGAS process.
The final proces s design for any gasification plant will logically depend upon
many factors including the particular coal feed, the plant location, the
enginoering contractor, and the plant owner, among others. This particular
*
plant design is sized to produce 3.0528 GJ /s (250 billion Btu/day) of syn-
thetic natural gas (SNG). The flow diagram shows details for a minimum
dischc.rge system in which all process water is recycled to the process
after water treatment, and most gaseous effluents are treated to reduce
polluta.nt concentrations to acceptable levels. For example, the concentration
of sulfur dioxide (SOz) in the steam-plant stack-gas is reduced to 5. 159 kg
per 1C GJ of energy produced (1.2 lb SOz/million Btu). Measurements of
trace- element levels in the by-product streams will provide valuable data
on rec overy efficiencies for each process, on potential environmental
problEms, and on the salability of each particular by-product. In accord-
ance with this test plan, the SNG product stream should be analyzed for all
trace elements; however, it is expected that extremely low levels of volatile
trace elements will be present, whereas nonvolatile elements will be un-
detecta.ble.
Ta.bles 1 through 3 describe quantitatively the solid, liquid, and gaseous
streanls for process designs based on bituminous, subbituminous, and lignite
coal feeds. The first part of each table details the compositions of the gas-
eous and liquid streams; the second part describes the solid and by-product
streanlS from the process.
*
Metr:.C conversions used -
K (degrees Kelvin) = (oF - 32)/1. 8 + 273.15 = "C + 273.15
ml)l (g)/s = (lb-mol/hr)(0.1259979)
Nrn3/s = (cu ft/day)(3.277432 X 107)
J / s = (B tu / da y )( 0 . 0 122 1134)
kl\ /m;'. = (psia)(6. 894757)
kg = (lb)(O. 45359237)
Where convenient, the allowed prefixes were substituted for scientific
notation. Hence the energy produced by a commercial coal-gasification
plant is recorded as 3.0528 GJ/s instead of 3.0528 X 109 J/s (250 billion
Bt~/day). .
2
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Table 1, Part 1. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING TT.T.Tl\f()!S l'TO. 6 CO_I-\L PP.ODUCI!'JG 8'1.89 !,;~3/C S~;c:
oc
......
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Combined Feed Acid Gas
CO-Shift Shift ~o ~atrr Treatment Waste Water Feed to Sulfur
Stream Description Raw Gas Feed By-Pass cru nit Feed to Treatment Guard Unit
Stream Number 2a 3 4 5 6b 7
Temperature. K 590 480 480 325 325 310
Pressure, kN / m' 7960 7895 7895 1760 7720 7445
Component gm mol/s mol 10 gm mol/s mol1o gm motls mol % gm mol/ s mol 10 gm motls mot 10 gm motls mol'1o gm motls mol 10
CO 2925.3 19.84 1950.2 16.74 975. I 22.25 1424. 3 8.88 1423.7 12.04 1422.5 18.00
COl 1I87. 2 14.83 1458.2 12. 51 729.0 16.64 3691.0 23.02 3647.1 30.85 11. 1 0.14
Hl 3045.0 20.66 2030.0 17.42 1015.0 23. If> 4549.3 28.37 4547.3 38.46 4532.3 57.33
HlO 2457.1 16.66 4525.8 38.84 819.0 18.63 3837. 8 23.93 20.8 0.18 6933..4 100.00
,.j:>. CH. 1922. 7 13.04 1281. 8 II. 00 641.0 14.63 1922. 7 11. 99 1921. 8 16.26 1916.7 24.25
CZH6 63.3 0.43 42.2 0.36 21. 0 0.48 63.3 0.39 63.3 0.54 15.0 0.19
C6H6 18.8 0.13 12. 5 0.11 6.3 0.14 18.8 0.12 17.9 0.15
NH, 79.1 0.54 52.8 0.45 26. 3 0.60 82.4 0.51 0.03
HCN 4.9 0.03 3. 3 0.03 1.6 0.04 1.6 0.01 0.04
H,S 171. 6 1. 16 114.4 0.98 57.2 I. 30 171. 1 1. 07 169.9 1. 44 0.03 Trace 0.10 ppmV
cas 1.5 0.01 1.0 0.01 0.5 0.01 2.0 0.01 2.0 0.02
N, 7.4 0.05 4.9 0.04 2.5 0.06 7.4 0.05 7.4 0.06 7.4 0.09
-I Phenol 1.0 0.6 0.01 0.4 0.01 1.0 0.01 0.03
m Oil 1860.4 12.62 ~ 1. 50 87. 3 1. 99 262.0 ~ 0.8 ~
n Total 14745.3 100.00 11652.3 100.00 4382.2 100.00 16034.7 100.00 11822.0 100.00 6933.53 100.00 7905.0 100.00
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(I> Table l, Part 2. S T REAM COMPOSITIONS AND FLOW RATES FOR HYGAS- BASED COMMERCIAL
-i GASIFICA TION PLANT USING ILLINOIS NO. 6 COAL PRODUCING 84.89 Nm3 / s SNG
-i
Methanation Wa.te Gae Oil-BTX Hl5 to Scav.gcd
c: Stream Descripti!.. Feed Gas Product to Stack to Storage Oil Foul Water ~ ---9.!.!-
-i Stream Number 8 9 10c 11 IZ 13 14 15
m Temperature. K 310 310
Pros8ure, kN/m' 1410 6895
Component gm mot'. mol % 1m moll- mol ~ 11m mo". ~ 11m moll. mol tf. 8m moll. ~ 1m moll. ~ ~ ~ gm molls mol ~
14ZZ. 5 18.0~ 3.5 0.10 1.1 0.03 0.6 0.01 0.6 I.Z
CO
CO, II. 1 0.14 4.8 0.13 3Z37. 6 97.84 43.8 0.71 398.4 10.00 43.8 86.45
0 H, 453Z.3 57. B Z35.1 6.54 15.0 0.45 Z.O 0.04 Z.O
3.97
H,O 0.3 0.01 5460. 5 97.59 0.8 I. 49
" CH. 1916.7 Z4. Z5 3HZ.0 93.01 5. Z 0.16 0.9 O.OZ 0.9 1.14
e,H, 15.0 0.19 48.3 I. 46
C,H, 17.9 6.39 0.9 O.OZ
U', NH, 8Z.4 1.46
HCN 1.6 0.03 1.6 3.16
C') H,S 0.04 0.3 0.11 O. Z 0.08 1.0 O.OZ 169.8 Z9.83 1.0 I. 94
COS 0.97 0.03 0.004 1.0 0.11 0.004 0.01
~ 7.4 0.09 7.4 O. ZI
N,
(I> Phenol 1.0 O. OZ
Oil uJ!~ ~ ~ ~ .m.:.!.. ~
Total 7905.0 100.00 3593.1 100.00 B09.1 100.00 Z80.1 100.00 Z61.4 100.00 5595. 7 100.00 569. Z 100.00 50.7 100.00
-i
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&SZ.O) kl/a 01 bip-pre.aure atearn ia added to the CO-.hilt leed.
bW.ltewater (6) include. diachargca born the acid-gal and tail-gal treatment unit.,
the ammonia recovery unH. oil-BTX Itor&80. and the methanation and drvina unit..
Sampli?8 may be dono at the lource or .t the waltewater-treatment influent pipe.
Water .. derived from coal in the drying process and cleewhere in the sy.tem via
condensation. All proce.. water i. routed to the wa8tewater treatment facility for
eventual recydina.
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cCa.8eou8 e.ffluenta from the. steam plant, ta..i1-gas treatment. and acid-gas regeneration
un.lt8 are .Included under th.l. column. A. 1n b. above, the ..mpling may be done at
the source or at the influent to the wastewater-treatment plant.
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Table l~ Part 3. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFTCA TION PLANT USING ILLINOIS NO.6 COAS PRODUCING 84.89 Nm:J / s SNG
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Coal Feed
from Storage
Stream Description
m
Stream Nllmber
A
183.92kg/s
(6.51. moisture)
Component *
o
C
."
H
°
0"' N
C') S
Ash
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Total
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wt. '70 dry
69.40
4.80
8.71
1. 35
4.20
11. 54
100.00
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*Note other elements shown in Table 4.
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Coal to Coal 1.0 Pretreatment Gyp~um and Steam Plant Ash
Steam Plant Pretreater Gases. Fines, Oil Excesf:; Lime and Spent Char
--- .-
B C Da E F
3B.&Bkg/s 133.29kg/s gmol/s mol % 13.86 kg/s 23.6 kg/s
(dry) (dry)
Ultimate analysis of composite
bituminous coal sample is the
same as stream A.
(Illinois No.6 Seam)
CO 199.9
CO. 358,6
H.
HzOl152.0
CH. 26.3
CZHb 13. 2
C,Hs 26. 3
H.S
N. 3728.8
0. 135.8
Ar 4B.l
SO.~
Total
5728.5
3.49
6.26
10.31. Carbon
20.11
0.46
0.23
0.46
0.31. Sulfur
65.09
2.37
0.84
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Table 1, Part 4. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING ILLINOIS NO.6 COAL PRODUCING 84.89 Nm3 / s SNG
Ge
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Cyclone Steam To Oxygen To Recycle By Product By Product By Product By Product
Stream Description Fines OG OG Oil Oil-BTX Phenols Ammonia Su Ifu r
Stream Nutnber b J K L M N" 0
H
a.a kg Is 124.70 kg/s 34.06 kgl s 215.79 kg/s 5.0lkg/s 0.16 kg/s 1. 40 kg/s 7.08kg/s
gm moll s gm moll s gm molls gm molls gm moll s
Component 1598.4 C6H6 17.9 C6H6 0.88 l'!'H3 82.4 Sulfur 22 0: 98
C 75.60 (oil mol. wt. HzS 0.3 Phenol ,). 98
H ~.l4 135) ."O~I 26.7
0 3.46
N 1.38
S 1. 46
Ash 15.86
Total 100.00 44.9 1. 86 82.4 220.98
Notes:
aThe pretreater effluent includes 5728.5 g-mol/s off-gases. 0.35 kg/s tar and oils. and
1.56 kg/s coal fines - to be used as fuel for steam generation. See Appendix A
for an analysis of tars and oils from the HY GAS pretreater and from tho Synthane
gasification process.
B75030539d
b Of these cyclone fines, 44.9'7. are less than 315 mesh ( < 44 /lm).
(X)
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To.....,...c "'-', .Lar....i.. 0....j.\~.L')'..1.V.L VVJ.V.li ,-,,0i...1..L,-,i'l0~.L-'f.1J .i:.l....J'-IVY .1.'\.£'""')..1...1..:.10 ..1.''-'.1.'\. .L~.1.~.C'3.u-~~IJ.c...LJ \"".,J'-J'iV.l.1Vl...c..,.L'\.v.1..C'3...L..t
GASIFICA TION PLANT USING MONTANA SUBBITUMINOUS COAL PRODUCING 85.21 Nm3 / s SNG
~
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Combined Feed Acid Gas
C OShift Shift to Water Treatment Waste Water Feed to Sulfur
Stream Description Raw Gas Feed By-Pass Scrub Unit Feed to Treatment Guard Unit
Stream Number 1 2a 3 4 5 6b 1
Temperature, K 590 480 480 325 325 310
Pressure. kN/mz 1960 1895 1895 1760 1720 1445
Component gm moll s mol '70 gm moll s mol '70 gm moll s mol '70 gm moll s mol '70 gm moll s mol '70 gm moll s mol '70 gm moll s mol '70
CO 3548.2 21. 91 2365.5 19.31 11 82. 7 24.99 1660.3 9.78 1659.6 12.89 1658.3 19.29
COz 2217.7 14.11 1518.5 12.40 759.1 16.04 4166.6 24.54 4122.8 32.02 12.6 0.15
Hz 3420.6 21.18 2280.1 18.62 1140. 2 24.09 5309.6 31. 26 5307.5 41. 22 5288.8 61.51
HzO 2876.4 17.81 4700.1 38.38 960.1 20.27 3770.9 22.20 22.7 0.18 7191. 9 100.00
CH. 1576.0 9.76 1050.1 8.58 525.3 11. 10 1576.0 9.28 1575. 1 12.24 1568.5 18.24
00 CZH6 127.6 0.79 85.0 0.69 42.6 0.90 127.6 0.75 127.6 0.99 67.2 0.18
C6H6 28.3 O. 18 18.9 0.15 9.4 0.70 28.3 0.17 21.5 0.21
NH] 24.7 0.15 16.5 0.13 8.2 0.17 25.1 0.15 5 ppmW
HCN 1.5 0.01 1.0 0.01 0.5 0.01 0.5 12 ppmW
HzS 30.2 0.19 20.1 0.16 10.1 0.21 30.1 0.18 28.8 0.22 0.2 ppmW Trace 0.1 ppmW
cas 0.3 0.2 0.1 0.3 0.3
Nz 2.3 0.01 1.5 0.01 0.8 0.02 2.3 0.01 t.3 0.02 2.3 0.03
Phenol 1.0 0.01 0.6 0.01 0.4 0.01 1.0 0.01 20 ppmW
Oil 2233.0 ~ 188.7 ~ 94.3 ~ 283.0 1.67 ~ 0.01
Total 16147.8 100.00 12Z48.5 100.00 4733.1 100.00 16982.2 100.00 10459. 100.00 1191.9 100.00 8591.1 100.00
~
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Table 2, Part 2. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING MONTANA SUBBITUMINOUS COAL PRODUCING 85.21 Nm3/s SNG
Q')
-
-.J
0'
MethaDAtion Wa.te Ga. By-Product H,S To Scav&gcd
Stream De8cription Feed Ga. Product To Stack Oil-BTX .Qi! Foul Water ~ ~
Stream Number 9 10c 11 IZ 13 14 I~
Temperature. K 310 310
Pre..ure. kN/m I 7410 689~
Component 8m moll. mol ~ 8m moll. mol 1.0 8m moll. mol ~ 8m moll- mol ~ 8m moll. mol,.. 8m mol/a mol-? am moll- mol? gm moll. mol".
CO 16~8. 3 19.Z9 3. ~ 0.10 1.4 0.03 0.6 0.01 0.6 I. Z7
CO, IZ.6 O.I~ 6.9 0.19 4043.1 97.86 43.8 0.79 67.0 70.00 43.8 88.37
H, SZ88.8 61. ~I Z3~.1 6.51 18.8 0.46 Z.O 0.04 Z.O 4.06
H,O 0.3 0 01 5496.7 98.63 0.8 I. 5Z
CH. 1568.5 18.Z4 3363.3 93.13 6.6 0.16 0.9 O.OZ 0.9 I. 79
CzH, 67. Z 0.78 60.5 I. 46
C,H, Z7.5 8.84 0.9 O.OZ
NH, Z5.7 0.46
HCN 0.5 0.01 0.5 I. OZ
H,S 0.04 0.5 0.16 0.38 0.13 1.0 0.01 Z8.6 Z9.86 9.8 I. 98
COS 0.16 0.01 Z ppmW 0.16 0.14 76 ppmV
N, Z.3 0.03 Z.3 0.06
Phenol 1.0 0.01
Oil So, 0.84 O.OZ Z83.0 91. 00 Z8Z. ZZ 99.87
Total
8~97. 6 100.00 3611.4 100.00 4131. 44 100.00 311.0 100.00 Z8Z.6 100.00 5573.1 100.00 95.76 100.00 ~8.4 100.00
~:
.50.1611.81. of hip-pre..ure ateam are added to the CO-.hilt feed.
bFive wa8tewater atream. are combined under We beading: a<:id 8.8. tail-ga8 treatment, the ammoni,
recovery unit. o.i1-BTX ataralc. and methanauoD and drying waatewater. W.atewater aampling may
be done at each lource 8eparately or at the waUcwater...treabnent influent pipe.
CThree waste la. .tream. are combined here: .team plant, uH-8a. treatment, and acid-ga. regeneration ga.
Uream.. Sampling. may be done at each .ource or in the stack.
(X)
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Table 2, Part 3. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASJFTCA TION PLANT USING MONTANA SUP BITUMINOUS l.OAL PFV)T>l,rc.INC; HI.). II Nm~ is SN<;
Stream Description
Stream Number
Coal Feed
from StoraRe
A
Z48.61 kg/s
(ZZ. '70 Moisture)
wt '70 dry
68.12
ComDonent *
C
H
o
N
S
Ash
4.64
18.57
0.85
0.66
~
100..00
Total
*
Note other elements shown in Table 6.
Coal to
Steam Plant
B
48.72 kg/s
(6.5'70 Moisture)
wt '70 dry
Coal t.o Slurry
Fced SY""~81:~
C
158.68 kg/s
(6.5% Moisture)
wt % dry
Pretreatment
Off Gases, Fines, Tars
Da
Gypsum and
Excess Lime
Eb
2.18kg/s
Ultimate analysis of
composite subbiturninous
coal samples is the same
as stream A.
(Montana s ubbituminous)
~
.......
-..
a-
Steam Plant Ash
and Spent Char
F
20.20 kg/s
10.2% Carbo"
O. 7 "/. Sulfur
B75030540c
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Table 2, Part 4. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING MONTANA SUBBITUMINOUS COA;L PRODUCING 85.21 Nrn3/s SNG
Stream Description
Stream Number
C:omponent
C
H
o
N
S
Ash
Cyclone
Fines
HC
24.73 kg/s
Steam to
OG
I
1I4. 32 kg/s
Oxygen Recycle By- Product By-Product By-Product By-Product
to OG Oil Oil-BTX Phenols Ammonia Sulfur
J K L M N 0
38.1 kg/s 263.3 kg/s 8.93 kg/s 0.16 kg/s 0.44 kg/s 1. 22 kg/s
gm moll s gm molls gm moll s gm moll s gm moll s
1 950. 1 C6H6 27.5 C6H6 0.88 NH3 25.7 Sulfur 38.16
(Oil mol.wt. HzS 0.5
135) Oil 50.1 Phenol 1. 01
78.1
1. 89
25.7
Notes:
apretreatment. to remove coal agglomerating tendencies. is not required for Montana
subbituminous coal. Fines are produced in the grinding and crushing operation
that will be used to fuel the steam boiler.
bSulfur content of Montana subbituminous is generally < I %.This value of gypsum and
excess lime has been correlated from data on Illinois No.5 coal with 4.45 per cent
sulfur. It is possible that the SOz in the steam-plant stack gas may be low enough
to eliminate the need for lime or any other form of treatment
c
The ultimate analysis of the cyclone fines is not available for subbituminous coal.
00
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Table 3. Part 1. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICA TION PLANT USING LIGNITE COAL a PRODUCING 85.78 Nm3/s SNG
Combined Feed Acid Ga s
CO-Shift Shift to Water Treatment Waste \vater Feed to Sulfur
Stream Description Raw Gas Feed By-Pass Scrub Unit Feed to Treatment Guard Unit
Stream Nwnber 2b 3 4 5c 6d 7c
Temperature. K 600 600 685 310 310 310
Pressure, kN/mz 7685 7550 7480 7445 7340
Component gm molls mol '70 gm moll s mol '7. gm molls mol '70 gm molls mol '70 gm molls mol '70 gm moll s mol '70 gm moll s mol '70
CO 1553.2 11.42 1553.2 13.95 781. 9 7.55 781.9 7.69 781.9 12.97
COz 2006.1 14.75 1905.8 17.12 1 905. 8 18.39 1866.2 18.35 14.0 0.13 60 3 1.00
Hz 1960.1 14.42 1960.1 17.60 N/A 2731.4 26.36 2731.4 26.87 2731.4 45.31
HzO 4015.7 29.53 3054.4 27.43 2283.1 22.03 2283.1 22.46 11110.7 99.86 7.8 0.13
CH. 2252.0 16.56 2252 20.23 2252.0 21. 73 2252.0 22.15 252.0 37.35
CzHo 109.7 0.81 109.7 0.99 109.7 1. 06 109.7 1. 08 109.7 1. 82
C)HS 36.7 0.27 36.7 0.33 36.7 0.35 36.7 0.36 36.7 0.61
CoHo 18.2 0.14 23.3 0.21 23.3 0.23 2.4 0.02
HzS 44.3 0.33 44.3 0.40 44.3 0.43 42.6 0.42 1.7 0.01
NH) 27.8 0.20 27.8 0.25 27.8 0.27
Nz 48.6 0.36 48.6 0.44 48.6 0.47 48.6 0.48 48.6 0.81
Oil 1524.7 II. 21 116.8 1. 05 116.8 1.13 11. 7 0.12
Total 13597.1 100.00 11132.7 100.00 10361.4 100.00 10166.3 100.00 11126.4 100.00 6028.4 100. 00
ex>
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z
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-I Stream Description
C Stream Number
-I Temperature, K
m Pressure, kN/mz
Component
o
CO
COz
Hz
HzO
CH.
CZH6
>- C, H 8
u..'
C6H6
HzS
NH,
Nz
Oil
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Table 3, Part 2. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING LIGNITE COAL PRODUCING 85.78 Nm3/s SNG
00
.......
.--.)
0'
Methanation Product Process Oil-BTX Foul HzS To Scavaged
and Drying Gas Waste Gas to Storage Oil Water Claus Gases
--
8 9 10e 11 12 13 14 15
310 310 390 310 310 310 310 310
7340 6995 7445 7340 7340 7340 7340 7340
gm mol/ s mol % gm mol I s mo11o gm moll s mol '7. gm molls mol '}'. gm molls mol% gm molls mo1% gm molls mol1o gm mol I s mol'j{
781.9 12.97 3.7 0.10
60.3 1. 00 46.3 1. 28 1734.9 100.00 39.6 0.62 71.04 63.38
2731.4 45.31 157.6 4.34 N/A
7.8 0.13 0.5 0.01 6284.4 98.88
2252.0 37.35 3373.7 92.93
109.7 1.82
36.7 0.61
23.3 16.91 19.8 16.01 1.1 0.02
1.7 0.03 40.9 36.49
27.8 0.43 0.14 0.13 (COS)
48.6 0.81 48.6 1.34
114.5 83.09 103.9 83.99 1.2 0.02
--
6028.4 100.00 3630.4 100.00 1734.9 100.00 137.8 100.00 123.7 100.00 6355.8 100.00 112.1 100.00
Notes:
aThe flow rates and stream compositions listed in this table are approximate, having been derived from an early
design based on lignite coal. Where stream compositions are unspecified. the original design data were judged
inappropriate for inclusion.
bThe HzO flow rate in stream 2 reflects the addition of 52.47 kgl s of reaction steam to the CO- shift reactor.
CStreams 5 and 7 are approximate. The early design included a purification unit prior to the gas-shift reactor
to remove COz and HzS, and another unit following the gas-shift reactor to remove HzO, benzene, COz, and any
remaining HzS from the product-gas stream.
dWastewater to the water treatment facility, is collected from the coal-drying units, the quench tower,
purification unit, the methanation unit, and the product-gas dryer.
eCOz from the acid-gas treatment only.
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c
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Stream Description
Stream Number
"
"
>
,
......
~
Component *
C
H
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S
VI
Ash
Total
-I
(X)
"-
--.J
0'
Part 3. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING LIGNITE COAL PRODUCING 85.78 Nm3 Is SNG
Coal Feed
from Storage
A
292.1 kg/s
(35% Moisture)
65.45
4.45
19.85
0.92
0.78
~
100.00
*
Note other elements shown in Table 7.
m
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Coal to
Dryer, Offsite
Ba
19.7kg/s
(351. Moisture)
Coal to Slurry
Feed Systcm
C
2n.4 kg/s
(35 '7. Moi sture)
Ultimate analysis of composite
lignite coal samples is the same as
strea.zn A.
(Montana lignite)
Pretreater
G~ ses, Fines, Oil
Db
Gypsum and
Excess Lime
EC
3.43 kg/s
Ash
F
23.6l kg/s
8.2% Carbon
0.07% Sulfur
Electro-gasified
Char to
MHD and Boile
G
49.00 kg/"
67.75
0.00
0.12
O. 54
0.7Z
~
100.00
B75030541 c
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Table 3, Part 4. STREAM COMPOSITIONS AND FLOW RATES FOR HYGAS-BASED COMMERCIAL
GASIFICATION PLANT USING LIGNITE COAL PRODUCING 85.78 Nm3/s SN9
00
-
-.J
0'
Stream Description
Stream Number
Component
C
H
o
N
S
Ash
Cyclone
Fines
Hd
Z9.5kg/s
Steam From
Boiler
Electric
Power To ETG
Recycle By- Product By-Product By-Product By-Product
Slurry Oil Oil- BTX Phenols Ammonia Sulfur
K Le Me Ne Oe
109.6 kg/s 10.7 kg/s 0.19. kgl s 0.47 kg/s 1.36 kg/s
140Z.8 gm molls 93. Z am molls Z.3 gm molls Z7.8gm molls 4Z.6 gm moll s
I
54.6kg/s
J
Z.4TJ
58.9
3. 15
10.67
0.99
0.84
Z5.45
/
Total
100.00
Notes:
aThis quantity of coal is conveyed to a packaged steam boiler and to a MHD unit to generate electricity for an
electrothermal gasifier (ETG).
bLignite does not require pretreatment.
c The value is proportiona~e to a design based on bituminous coal.
dOf these cyclone fines. 43.5'10 are less than 3Z5 mesh. k44j1m)
eThe flow rates of these streams are computed in proportion to values from a Montana sub bituminous design
and are approximations.
00
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W
-------
8/76
8943
TY;Jical operating temperatures (in K) and pressures (in. kN/m~) are
listed f')r the process streams where this information is available. Solid
and by-product streams are assumed to be at ambient conditions. The
flow rai:es of the proces s streams are calculated and tabulated in kilograms
per second (kg/ s) or moles per 13 econd (moll s). Both are SI-approved
notatior..s .1Z, 53 This test plan could be applied to other gasification processes
without major alterations, even though it is written specifically for the
HYGAS Proces s.
Coals
Thc~ proximate and trace-element analyses of coals may vary consider-
ably frem mine to mine, or even from seam to seam. Therefore, it is
imperative that a test plan be flexible enough to allow for fluctuations in
feed cOJnposition or proces s conditions that might occur during gasification.
For thi!i reason, proces s mas s balances for three different coals are
presented instead of one mass balance for an "average" coal, which may
not exist. Each of the mas s balances in Tables l, 2, and 3 is bas ed upon
the ulthnate analysis of a composite of several coal samples from the same
seam. We believe this approach is valid and representative, even though the
properLes of certain coals necessitate the use of special handling and pre-
treatment steps prior to gasification.
Coal Pretreatment
Bitum.inous cQals ha ve significant agglomerating tendencies which must
be remclved prior to gasification. If fed directly to the gasifier, a bituminous
coal wOllld agglomerate, form clinkers, and plug the reactor. One method
of removing the sticking property is to mildly oxidize the feed material (at
700 K) to drive off some volatile matter and to cover each particle with a
nonsticking layer of oxidized material.
Th€ pretreatment proces s involves the production of sizable quantities
of off-gclses, coal fines, tars, and oils which must be utilized in some way
or discarded. Significant quantities of certain trace and minor elements
are alse volatilized during pretreatment, contributing to the overall losses
as showJ. in Table 4, Column D.
16
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
Table 4. CALCULATED FLOW RATES OF TRACE AND MINOR 00
-
ELEMENTS IN A HYGAS-BASED, COMMERCIAL COAL GASIFICATION -::
0'
z PLANT USING ILLINOIS No. 6 SEAM BITUMINOUS COAL
'"
-f ~tream .l-'retreat~r Uxygasilier Hot Oil Waterb Acid-Gas Sulfur Methanati0'd Product
Description Coal Feed to Pretreater Losses Char Quench Scrub EffluentC Guard Condensate Gas
Stream Number .:; D G K Il, 13 II, 14 P 6 9
-f * .ws(X 103)
E1emp.nt -ppm- kg/s (X 10')
C
-f Sb 1.1 0.15 0.043 0.096 0.008 0.003 0.0 0.0 0.0 0.0
m As l4 3.l 0.35 l. 1 0.3 O.l 0.l5 0.0 0.0 0.0
Ba 31 4.1 0.0 4.1 0.0 0.0 0.0 0.0 0.0 0.0
Be 1 O. 13 O.Ol 0.10 0.01 0.0 0.0 0.0 0.0 0.0
Bi 1.1 0.15 O.Oll o.on 0.050 0.006 0.0 0.0 0.0 0.0
B lOO l7.0 0.73 l4.0 l.O 0.l7 0.0 0.0 0.0 0.0
0
Cd 0.89 O.ll 0.044 0.Ol8 0.040 0.008 0.0 0.0 0.0 0.0
." Ca 3500 470.0 100.0 310.0 60.0 0.0 0.0 0.0 0.0 0.0
CI l300 310.0 110.0 80.0 5.0 110.0 4.0 1.0 0.0 0.0
Cr 15 l.O 0.0 l.O 0.0 0.0 0.0 0.0 0.0 0.0
...... Co 3.6 0.48 0.0 0.48 0.0 0.0 0.0 0.0 0.0 0.0
C') -J Cu
19 l.5 0.0 l.5 0.0 0.0 0.0 0.0 0.0 0.0
~ F 61 8.1 0.l9 6.0 0.5 0.81 0.5 0.0 0.0 0.0
'" Ge 4.3 0.57 0.033 0.5l 0.015 O.OOl 0.0 0.0 0.0 0.0
Fe 14,000 1870.0 73.0 1730.0 65.0 l.O 0.0 0.0 0.0 0.0
Pb 11 1.5 0.73 0.77 0.0 0.0 0.0 0.0 0.0 0.0
Li 33 4.4 0.0 4.4 0.0 0.0 0.0 0.0 0.0 0.0
-f Mg 570 76.0 0.0 76.0 0.0 0.0 0.0 0.0 0.0 0.0
Mn 48 6.4 0.50 5.l 1.1 0.1 0.0 0.0 0.0 0.0
m Hg
O.ll 0.016 0.013 0.0006 0.0013 0.0006 0.0004 0.0001 0.0 0.0
n Mo 7.0 0.933 O.Ol 0.906 0.007 0.0 0.0 0.0 0.0 0.0
:J: Ni 15 Z.O 0.09 1.9 0.01 0.0 0.0 0.0 0.0 0.0
N 10.400 1390.0 0.0 3l0.0 70.0 950.0 40.0 9.0 1.0 0.0
Z
K 1700 lZ7.0 0.0 ll7.0 0.0 0.0 0.0 0.0 0.0 0.0
0 Sm 0.74 0.098 0.0 0.098 0.0 0.0 0.0 0.0 0.0 0.0
r Se 13 1.7 0.l4 1.0 0.1 O.lO 0.16 0.0 0.0 0.0
0
* 00
C') Parts per million ~
~
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-------
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Table 4, Cant. CALCULATED FLOW RATES OF TRACE AND MINOR 00
'"
ELEMENTS IN A HYGAS- BASED,COMMER CIAL COAL GASIFICATION -..:!
0"
PLANT USING ILLINOIS No. 6 SEA~v1 BITUMINIOUS COAL
~trp~m ~':-=~:-=::~i:- ' "-.--- _: .: - - "IV"" '-'&.1 nait:.Eh ACl(i-~a,! Sullur Methana tiO?! Product
--,&"''''',,''''''''''''
Description Coal Feed to Pretreater Losses Char Quench Scrub Effluent Guard Condensate Gas
Stream Number C D G 1< 12, 13 II. 14 P 6 9
* .!&is(X 10')
Element -ppm-. "8/. (X 10')
Si ZO,OOO 2670.0 0.0 Z670.0 0.0 0.0 0.0 0.0 0.0 0.0
Ag 0.1 0.013 0.0042 0.0048 0.003 0.001 0.0 0.0 0.0 0.0
Na 1400 187.0 0.0 187.0 0.0 0.0 0.0 0.0 0.0 0.0
Sr 37 4.9 0.0 4.9 0.0 0.0 0.0 0.0 0.0 0.0
S 38,000 5100 1150.0 1040.0 120.0 200.0 2570.0 20.0 0.0 0.0
Te 8.1 1. 08 0.25 0.64 0.09 0.05 0.05 0.0 0.0 0.0
Sn 2.0 0.27 0.07 0.13 0.06 0.01 0.0 0.0 0.0 0.0
Ti 770 103.0 .0.0 100.0 3.0 0.0 0.0 0.0 0.0 0.0
V 17 2.3 O.ZI 1.9 0.16 0.03 0.0 0.0 0.0 0.0
Yb 0.56 0.075 0.0027 0.069 0.003 0.0003 0.0 0.0 0.0 0.0
..... Zn 49 6.5 0.99 4.8 0.60 0.11 0.0 0.0 0.0 0.0
00 Zr 35 4.7 0.0 4.7 0.0 0.0 0.0 0.0 0.0 0.0
VI
-t
-t
C
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VI
Notes:
-t
apretreater losses arise from the volatilization of elements at lower
temperatures (700K), and are in the form of tars, oils, fines. and
off-gases. All of this material is burned in the steam plant. Volatile
compounds may be lost to the stack unless cleaned by scrubbing or
some other method. Figure 1 incorporates a calcite scrubber to remov!"
SOz from the stack gas.
m
()
:t:
Z
bTwo streams are split here: The oil stream is recycled to the slurry
preparation and may accumulate trace elements. The water stream
contains phenols, NH.-(F, CI) to be separated, and the treated water
to be recycled. It is important to note that the by-products may show
enrichment of some trace elements. .
o
r
cThe sour gas from the acid-gas treatment unit is sent to the Claus
plant. It contains much of the acidic compounds of COz, HzS, AszO),
BlO" etc., and fine particulates. Oil is separated during regeneration
and is recycled. COl is released to the atmosphere with trace sulfur
compounds. Some gaseous, acidic elements, i. e., HzSe and HzTe. will
most likely end up in the Claus plant sulfur product.
dWater is condensed during methanation and may carry away other
trace elements. Almost total sulfur removal is accomplished during
methanation by adsorption onto the catalyst particles. The product
gas will be analyzed for the more volatile, toxic elements. but not
for the innocuous ones.
00
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8/76
8943
In the HYGAS process description (Figure 1, Table 1), the pretreater
by-products are consumed in the boiler for steam productlon. The primary
boiler fuel is coal, while pretreatment fuels provide a supplement. The
combined combustion gases from these fuels represent a considerable
source of potential pollutants, which ma y require the addition of larger
(but not more complex) atmospheric emission controls to the stack. Those
materials removed from the coal during pretreatment must be cleaned from
the stack gas, rather than handled in the normal gasification cleanup train.
For example, pretreatment of high-sulfur coals may volatilize 30'7'0 of the
sulfur as sulfur oxides, which would otherwise be removed during the acid-
gas treatment step as hydrogen sulfide.
By eliminating the coal pretreatment step (by mild oxidation) through pro-
ces s modifications and improvements, the overall gasification proces s
would be simplified, while the demands on the steam plant stack-gas clean-
up system would be reduced.
Coal Energy and Moisture Content
Lignite and subbituminous coals have low « 110) sulfur contents and low
agglomerating tendencies that make them the most "well-behaved" and
environmentally sound fuels for gasification.
However, each of thes e coals
has a higher moisture content and lower heating value than the bituminous
coal. Taken together, these factors require that much larger quantities of
lignite and subbituminous coal be conveyed to a gasification plant, in order
to produce the same quantity of SNG as would be obtained from bituminous
coal. For example, to produce 3.0528 GJ /s (250 X 109 Btu/day) of SNG
requires a lignite coal feed rate of 292.09 kg/s (27,818 tons/day) to the
gasification plant. The corresponding flow rate for subbituminous coal is
248.61 kg/s (23,678 tons/day), and for bituminous, 183.92 kg/s (17,516
tons/day). The lignite flow rate is 5910 higher than the bituminous flow rate.
Two factors can be considered here. First, in each design the total coal
energy conveyed to the gasification plant is within 1.510 of the others. The
totals range from 4.9902 GJ / s for lignite to 5.0750 GJ / s for subbituminous.
Second, of the 292.09 kg/s of lignite feed, 102.23 kg/s (3510) is moisture,
19
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much of which must be removed from the coal before gasification. A summary
of the beating values (HHV), moisture contents, and proces s mas sand
energy :How rates for three coals is shown below. Note that the quantities
of coal~nergy to the "Process" and to the "Offsites" are quite similar for
the bitu::ninous and subbituminous coals, differing from each other by les s
than 110 and 5% , respectively.
Heating
Moisture Value, Raw Coal Coal to Coal to Product Process
Coal Content Dry Basis to Plant Process Offsites SNG Energy Efficiency
--
-" % M J / kg GJ / s -%-
... (Btu/lb) (kg/s)
Lignite " 35 26, 28 39 4.9902 4.6532 0.3370 3. 0528 71.7
(11,300) (292.09) (272. 36) (19.72)
Subbitwnin:>us 22 26.2865 5.0750 3.8828b 1.1922b 3. 0528 67.2
(11,30 I) (248.61) (158.68) (48.72)
BitlUTlinou1: 6.5 29.3142 5.0513c 3.9151 c 1.1362 c 3. 0528 66.2
(12.603) (183.29) (133.29) (38.68)
a A magn<:tohydrodynamic (MHD) unit provided energy for an electrothermal gasifier in this design.
b Partiall, dried coal contains 6.5% moisture.
C Dried coal contains <1 ~/~ moisture.
ThE~ overall energy efficiency for the subbituminous design is 67.2'10,
that for the bituminous design is 66.2,/0. Because of the use of a magneto-
hydrodynamic unit for electric power generation in the lignite design, the
energy :cequirements are not comparable to the other two designs. However,
the efficiency of this early lignite-based design was calculated at 71.710.
Modes of Occurrence of Trace and Minor Elements in Coals
Trace and minor elements are present in raw coals, both in the mineral
matter c.nd in association with the organic materials. Many are present as
sulfides.. or in weathered coals as sulfates43, 50. Nitrogen is present almost
exclusively in five-to-six-member organic ring compounds. 34 Sodium
chloride deposited from saline ground water, is as sumed to be the predom-
inant source of chlorine in coa1.45, 50 Nitride compounds have not as yet
been detected in coal. Carbide compounds also have not been observed in
20
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coals, or to any extent in nature (except in iron meteorites and some
terrestrialiron41 ).
The Inodes of occurrence vary, yet there is evidence in the literature
that one or two forms of each element predominate.6,7,ZO,34,4s,so A summary
of the typical modes of occurrence of trace and lnlnor elements in coals as
reported in the literature is pres ented in Table 5.
Whenever literature searches failed to indicate the naturally occurring
form of an element in coal, its periodic properties and trends were followed.
For example, data on the occurrence of bismuth in coal is scant, but one
may anticipate that bismuth and lead would occur in similar compounds.
Hence bismuth is listed in the table as a sulfide, as is lead.
A study by Ruch et a!. 50 included a matrix of population correlation co-
efficients for potentially volatile trace elements in coal samples, which was
useful in the development of Table 5. The matrix indicated how frequently
one element was detected in a sample relative to the presence of another
element. For example, the highest correlation coefficient, 0.93, occurred
for the zinc-cadmium pair. These two elements are frequently observed
together in coal in the mineral sphalerite (zinc sulfide).
To expedite thermodynamic calculations in a later section of this report,
the element forms listed in Table 5 are assumed to be the only ones present
in the raw coal. Because each element has undergone a thorough thermo-
dynamic evaluation, errors in this assumption (and therefore in the table)
will not significantly affect the outcome of the analysis. If bismuth naturally
occurs in coal as an oxide and not as a sulfide as assumed, the results of
the test plan analysis would be the same.
This is assured, because the
same reaction calculations have been carried out for both the sulfide and the
oxide forms of bismuth. (See Appendix E, Table E-2, Part 1.) If the
necessary thermodynamic data for an element form are not available (as
in the case of bismuth sulfate), periodic property extrapolation must be
depended upon for the analysis. The analyses of every element in this
study are dependent upon the availability of accurate and reliable thermo-
dynamic data. Where data are lacking, that part of the analysis is incomplete.
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Table 5. TYPICAL MODES OF OCCURRENCE OF
TRACE AND lvUNOR ELEMENTS IN COAL
Element
Mode
Sb
Sulfide
Oxide, sulfide
As
Ba
Carbonate, sulfate
wi th Ca
OC *
Sulfide
Be
Bi
B
Cd
OC, bora te
Sulfide
Ca
Oxide, carbonate,
sulfa te
POC; sodium chloride
Cl
Cr
Co
POC, oxide
POC, sulfide
CuFeSz, sulfide
Cu
F
CaFz
POC, carbonate
Ge
Fe
Carbona te, sulfide,
oxide
Pb
Sulfi de
SQ :j:
Li
Mg
Mn
POC, carbonate, SQ
Carbonate in CaCO),
SQ
Hg
POC, element ,sulfide
*
OC - organic contribution.
t POC - partial organic contribution.
:J: SQ - silicates, clay, quartz.
INSTITUTE
o F
Element
Mode
Mo
Ni
Sulfide
Sulfide
N
OC
K
KCl, carbonate
SQ
Sm
Sc
Oxide
POC, sulfide,
iron selenides
Se
Si
Oxide, SQ
Ag
Element, sulfide,
SQ
POC, carbonate
POC, with Ca
POC, sulfides,
sulfa tes
Iron tellurides
Na
Sr
S
Te
Th
SQ
Sn
Carbonate, sulfide
Ti
POC, SQ
OC
SQ
Sulfide
V
Yb
Zn
Zr
Oxide, SQ
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Coal Ash Materials
The m.ineral matter of coal is comprised of materials which may under-
go reactions with proces s gas es in the hydrogasifier. Thes e materials
include silicates, calcite, alumina, tungstates, etc. Thermodynamic data
for many of the compounds are available, and further work should include
an investigation of their reactions in the hydrogasifier I s fluidized bed.
There is a synergistic effect between chlorine and trace elements
during combustion. 16 The presence of chlorine increases the volatilization
of elemental forms, such as arsenious oxide (Asz03)' On combustion, Asz03
volatilizes unless retained as arsenate or arsenites by carbonate minerals,
such as dolomite (CaC03 . MgC03) or barite (BaC03),among others. Per-
haps by reducing the chlorine content (as hydrochloric acid) from the gasi-
fier or by increasing the carbonate content, the trace elements may tend to
remain with the ash rather than be volatilized.
Pos sible Dis position of Trace and Minor Elements
Trace elements in the feed to a commercial coal-gasification plant
are subject to a number of reactions. The possible fates of thes e materials
are listed below with reference to Figure 2.
1.
2.
3.
4.
Coal storage and handling losses arise from the leaching of
trace elements from coal piles by rain water. Windborne dust
losses must be minim.ized.
The coal crushing and drying process will produce wastewater
that ma y contain trace elements.
During pretreatment at 700K, certain trace elements, such as
mercury or lead, may be volatilized to the fuel gas either in
the vapor phase or ads orbed on particulates. Oil, tar, and
fines resulting from pretreatment may also contain trace and
minor elements. This material is combusted along with the fuel
gas and is subjected to the stack gas emission controls. Thus,
some volatile trace elements may be lost to the stack gas.
In the light-oll vaporizer (LOV), the light oil is flashed and the
coal dried prior to gasification. Organic material, which is
soluble in light oil (organometallic compounds and/or metal
chelates) may in part be flashed directly overhead, condensed
23
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Z
II>
-t
COAL
STORAGE
-t AND
HANDLING
C
-t
m
CRUSHING
AND
DRYING
o
"TI
N
() ~ STEAM
BDILER
>
II>
-t
m
(")
::r
z
o
..
o
()
-<
FUEL GAS
TO BOILER
~
PRE-
TREATER
OIL, TAR,
AND FINES
TO BOILER
Figure 2.
--@
LS
SULFUR
STEAM l
PRODUCT
GAS .(;
OXYGEN
RECYCLE aiL
cp
SLURRY
PREP.
LOV
LIGHT OIL
VAPOR.
BY-PRODUCT
OIL-BTX
t
~ It
HOT OIL
QUENCH
TOWASTE WATER
TREATMENT cio
t -
-..J
0'
SL ~
OIL OIL-WATER
SEPAR.
SHIFT BYPASS
WATER ~ -0.0315 m' s
CO-SHIFT SCRUB WATER
CLAUS ~ ACID GAS r PHENOL AND
y
PLANT TREATMENT . L' NH) RECOVERY
G .
SULFUR
GUARD
METH.
',,1' SO!.fl) Si, l.:lJr'[n r.), ,.:' {;..\SI~\. In :-ir'~I!(ln j\.
I.dd.' .j
00 .
~
~
l.N
POSSIBLE DISTRIBUTION OF TRACE AND MINOR ELEMENTS
-------
5.
6.
7.
8.
8/76
8943
in the hot-oil quench unit, and thus recycled to slurry pre-
paration. Part of this material is expected to accompany the
coal to the hydrogasifier stage and react with HYGAS Proces s
gases. The unquenched fraction of organic material may pass
through the CO-shift reactor and be removed in the water
scrub unit. The organic phase is separated and recycled to
the slurry preparation unit; the aqueous phase is piped to the
wastewater treatment area. Coal fines not cycloned out and
recycled to the hydrogasifier may be entrained overhead.
Extremely fine particulates may pass completely through the
plant, possibly as fumes. It is important to note that these
particulates may be enriched in volatile trace elements due
to condensation in the LOV. 39
Other volatile trace elements may neither be condensed in
the LOV nor removed during the subs equent quenching and
scrubbing operations, but remain in the process gas stream.
Thes e compounds, or elements, will be removed in either
the acid-gas treatment unit or the caustic scrub prior to
methanation.
The coal feed material flows by gravity to the low- and high-
temperature reactors, where it is partially gasified. The
char goes to the steam-oxygen gasifier (OG), where the re-
maining carbon is gasified. The mineral matter in the feed
ultimately exits from the OG as low-car bon-content ash.
Some trace-element losses may be attributed to plating of the
material onto the surfaces of the reactor and other process
units. Similarly, some sulfur compounds will be adsorbed
onto the catalyst particles in either the gas shift or methana-
tion reactors, resulting in the poisoning of the catalysts.
Product streams from the purification units may contain
trace elements in the by-product oil-BTX, phenol, ammonia,
sulfur, and spent caustic.
These paths are many and varied, with complex mechanisms for each.
The calculations indicate the streams in which an element is likely to appear;
however, the element may appear much earlier or somewhat later than pre-
dicted. This depends in part on the nature of the coal and on its trace-ele-
ment composition.
Fluctuations in the proces s pres sure or temperature will not substan-
tially affect the appearance of the trace elements down stream unless the
variations of temperature or pressure are extreme. (See "Variability of
Operating Conditions," page 36.) A rapid increase in either parameter
would trigger automatic controls that would shut down the reactor.
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However, process fluctuations compound the problems associated with closing
the maE s balance around the plant, especially for the toxic elements mercury,
seleniwn, arsenic, cadmium, lead, and antimony. An analysis of the gas
from the Synthane Process done by Forney et al. 18 showed that mercury was
present in the gas from the gasifier but not in the final product. The pro-
duct ga:, from the HYGAS plant should be analyzed for volatile trace elements,
but is expected that, as in the Synthane product gas, their levels will be very
lowlS, perhaps because of amalgamation on colder parts of the methanation
catalyst bed.
Thermcdynamically Stable Forms of the Elements in HYGAS Proces s Units
Wi1h the information in Table 5, free-energy calculations were per-
formed to determine the most stable forms of each feed species in the pre-
treater J the hydrogasifier, and the CO-shift reactor. Thus, each element
was followed thermodynamically through the process to estimate its ultimate
form and distribution. The effect of individual reaction kinetics was not
included in this development and each reaction was as sumed to go to an
equilibrium condition. Some of the reactions which are likely to. occur in
each of the process units are included below, along with a discussion of a
convenient thermodynamic indicator - the operating region.
OpE:l'ating Regions
Th~ term "operating region" does not describe a physical location,
but mol' e a "where" with respect to system operating conditions. It is a
nwnerical value assigned to a certain reaction occurring in a given atmos-
phere a1 a given temperature. Operating regions can be calculated by sub-
stituting steady-state gas partial pressures into the usual equilibriwn-
constant equation:
Partial Pressures of Product Gases
Operating Region = log
Partial Pressures of Reactant Gases
This value can be used to determine the direction that the reaction should
go by comparing it with the equilibrium constant for that reaction. By com-
pleting this type of analysis on the numerous reactions considered likely to
occur in anyone reaction unit, the thermodynamically stable form of trace
26
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and minor constituents can be determined.
Several examples of operating region calculations and analys es are
pres ented in the section "Variability of Operating Conditions, " and Appendixes
D, E, and F.
Pretreatment
The reactions occurring in the pretreater are primarily oxidation
devolatilization, and polymerization reactions. Several oxidation reactions
were evaluated at 700 K and atmospheric pres sure for sulfate, sulfite, and
oxide stability. In general, the oxidation reactions strongly favor sulfate,
oxide, or carbonate formation, such as -
MS + 202 i!MS04
MS + 3/2 O2 ~MO + S02
MO + CO2 ttMC03
As the calculations progres s ed, it was as sumed that the sulfate or
oxide form of each element would be thermodynamically favored in the
pretreater. This mild oxidation is required to drive off volatile matter and
to char the surface of each coal particle slightly to reduce agglomeration.
The quantity of off-gases produced during pretreatment is considerable at
5728.5 g -moll s (157.4 kg/ s), (Refer to Table 1, Column D). Nitrogen
and water vapor account for 85 mol 10 of the off-gases; carbon monoxide
and carbon dioxide compris e 10 mol 'l~. Methane, ethane, oxygen, sulfur
dioxide, argon, and heavier hydrocarbons make up the remainder of an
essentially neutral reaction atmosphere.
Stearn Plant
The pretreater off-gases, combined with pretreater tars, oils, and
fines, supplement the fuel to the stearn plant. The total quantity of steam-
plant feed (i.e., off-gases, oil, tars, fines, and coal) amounts to .....194 kg/s
for bituminous coals. Because pretreatment is not required for nonagglom-
erating coals, the stearn-plant fuel supplement is correspondingly reduced.
The quantity of coal used for stearn production is approximately 30'70 of the
coal conveyed to the hydro gasifier .
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Th,~ combustion gases from a steam plant are scrubbed to reduce sulfur
dioxide emis sions to acceptable levels. It is, however, uncertain that the
SOz scrubber could completely eliminate the emission of the more volatile
trace e:.ements and this question must be resolved by actual sampling and
analysi:, of the combustion gas es.
EVlm though this project is directed toward evaluating the process
stream:> of a HYGAS-based facility, consideration of the plant's auxiliary
units sl:.ould be made with respect to potential pollutants. Larger stack gas
cleaning measures may have to be used on the steam plant, for example,
depending upon the quantity of sulfur in the coal being us ed.
Hydrogasification
The highly reducing atmosphere of the HYGAS unit, as well as the high
pressure and temperature, must be considered in determining the stable
element forms. Some of the reactions that were considered likely to occur
in the hydrogasifier are included here:
MO + 2HCI ~ MClz + HzO
MO + 2HF ~ MFz + HzO
MO + CO2 ~ MC03
MO + H2S ~ MS + H20
MS + 2HCI ~ MClz + HzS
MS + 2HF ~ MFl + HzS
MS + HzO + COl i! MC03 + HlS
MS04 + 4Hz;! MS + 4HzO
In additjon to these, reactions involving the elemental forms were included
for the Inore volatile species (Appendix E, Table E-2). The free-energy
changes for these reactions were calculated at a steam-oxygen gasifier temp-
erature of -BOOK (I 880 OF).
CO..Shift Reaction
The purpose of the CO-shift reactor is to adjust the hydrogen-to-carbon
monoxide ratio in the gas stream to about 3.1:1 prior to methanation. The
cobalt-nlOlybdenum catalyst is expected to equilibrate most materials that
contact :.t. Thus, an oxide that is more stable thermodynamically as a
28
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sulfide will react with sulfur compounds in the gas to form the sulfide.
The reactions are the same as those likely to occur in the HYGAS reactor
except they are evaluated at 600K.
At this point 'in the proces s, only the most volatile trace elements are
in the gas stream. Most of the fine particulate matter has been removed in
the hot oil quench and the cyclone, or has been adsorbed onto the catalyst.
29
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PROCESS ST EPS
The data contained in Tables 4, 6, and 7 are the result of thermodynamic
and solubility calculations to determine the fate of trace and minor elements
in coal during hydrogasification. The parameters used in these calculations
were ta ken from a design for a 3.0528 GJ / s (250 billion Btu/day) coal-gasi-
ficatior: plant based on the HYGAS Proces s. The coals used in the designs
are bitmninous, subbituminous, and lignite.
The tables include the raw coal concentrations (in parts per million) and
the calculated flow rates (in kg/s) for 38 elements in the major process
stream3. For clarity, the stream nun~bers and descriptions of these tables
are related to the Figure I proces s flow diagram.
Th\~ purpose of these calculations is to direct the search for trace
elements toward the proces s streams where they are thermodynamically,
or phys Lcally, more likely to appear. For example, according to trace-
element studies done at IGT, cobalt or lithium are not likely to appear
beyond the hydrogasifier; hence, any extensive analysis of the wastewater
from the acid-gas treatment unit for these elements may generate no us eful
information. With the guidelines from this present study at hand, however,
one may analyze process streams for specific elements and use the informa-
tion in the environmental assessment of a coal gasification plant. It should
be strefsed that the data extrapolated from process development unit test-
ing are preliminary estimates of the trace element distribution and should
be used cautiously, but may serve to.guiae a future search for trace elements
in pilot plant proces s streams.
The data used in the thermodynamic calculations were taken from a
number of references.S,17,21-23,26,27,42,S3,61,63,64 Where data on a certain
compound were available from two or more references, generally the data
from tht: more recently published source were selected. Data from one
reference were used with data from another as infrequently as possible,
becaus e of standard-state definition inconsistencies. If data were not a vail-
able, approximations were made based on the thermodynamic properties
of neighhoring elements in the periodic table. The trends of the stable
compour:ds in the hydrogasifier are outlined in Appendix C.
30
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Table 6. CALCULATED FLOW RATES OF TRACE AND MINOR ().
ELEMENTS IN A HYGAS-BASED. COMMERCIAL COAL-GASIFICATION
z PLANT USING MONT ANA SUBBITUMINOlJS COAT, 0
II>
~ Stream Oxygasifier Hot Oil Waterb Acid-Gas Sulfur Methanationd Product
, a Effluent c
Description . Feed Coal to Slurry Feed System Char Quench Scrub Guard Condensate Gas
Stream Number C G K 12, 13 11, 14 P 6 9
~
C *
Element - ppm - kg/s (X 10) kg/s (X 10)
~
Sb 1.2 0.18 0.14 0.03 0.01 0.0 0.0 0.0 0.0
m
As 18 2.7 1.3 0.65 0.35 0.40 0.0 0.0 0.0
Ba 1300 200.0 200.0 0.0 0.0 0.0 0.0 0.0 0.0
Be 0.98 0.145 0.113 0.032 0.0 0.0 0.0 0.0 0.0
Bi 0.72 0.11 0.06 0.045 0.005 0.0 0.0 0.0 0.0
0 B 85 13.0 9.05 3.5 0.45 0.0 0.0 0.0 0.0
." Cd 0.72 0.11 0.05 0.048 0.012 0.0 0.0 0.0 0.0
Ca 17,000 2520.0 2520.0 0.0 0.0 0.0 0.0 0.0 0.0
Cl 180 27.0 14.1 1.0 11. 9 0.0 0'.0 0.0 0.0
W Cr 14 2.1 1.6 0.5 0.0 0.0 0.0 0.0 0.0
C') .....
Co 4.4 0.65 0.65 0.0 0.0 0.0 0.0 0.0 0.0
~ Cu 8.8 1.3 0.92 0.38 0.0 0.0 0.0 0.0 0.0
II> F 71 10.5 6.7 1.0 1.8 1.0 0.0 0.0 0.0
Ge 2.7 0.4 0.3 0.03 0.03 0.03 0.01 0.0 0.0
Fe 9200 1370.0 1370.0 0.0 0.0 0,.0 0.0 0.0 0.0
Pb 1.9 0.28 0.15 0.09 0.04 0.0 0.0 0.0 0.0
Li 5.8 0.86 0.86 0.0 0.0 0.0 0.0 0.0 0.0
~ Mg 5800 860.0 844.0 110 5.0 0.0 0.0 0.0 0.0
I
m Mn 8.9 1. 32 1. 26 0.06 0.00 0.0 0.0 0.0 0.0
n Hg 0.73 0.11 0.0011 0.048 0.035 .024 0.0019 0.0 0.0
:I: Mo 2.1 0.31 0.28 0.03 0.0 0.0 0.0 0.0 0.0
Ni 23 3.4 3.1 O.~ 0.0 0.0 0.0 0.0 0.0
Z N 9200 1370.0 223.0 77.0 101. 00 50.0 9.0 1.0 0.0
0 K 340 50.0 49.0 1.0 0.0 0.0 0.0 0.0 0.0
r Sm 0.51 0.076 0.074 0.002 0.0 0.0 0.0 0.0 0.0
Se 1.7 0.25 0.09 0.03 0.07 0.06 0.0 0.0 0.0
0
C') * ex>
Parts per million -.0
~
W
-------
Table 6. Cont. CALCULATED FLOW RATES OF TRACE AND MINOR 00
--
ELEMENTS IN A HYGAS-BASED, COMMERCIAL COAL-GASIFICATION -..J
z PLANT USING MONTANA SUBBITUMINOUS COAL '"
en
-i
Stream . Fesd C'oal to Slurry Feed Systema Oxygasifier Hot Oil Waterb Acid-Gas Sulfur Methanationd Product
Description Char Quench Scrub Effluent c Guard Condensate Gas
-i
Stream Number C G K 12, 13 11, 14 P 6 9
C
-i
Element -ppm- kg/s (X 10') kg/s (X 10')
m
Si 13,000 1930.0 [780.0 150 0.0 0.0 0.0 0.0 0.0
Ag 0.24 0.036 0.034 0.0015 0.0005 0.0 0.0 0.0 0.0
Na 180 26.7 25.2 1.5 0.0 0.0 0.0 0.0 0.0
0 Sr 350 52.0 34.0 18 0.0 0.0 0.0 0.0 0.0
"TI S 9900 1470.0 490.0 58.0 86.0 831.0 5.0 0.0 0.0
Te 0.42 0.062 0.036 0.023 0.002 0.001 0.0 0.0 0.0
Sn 1.9 0.28 0.27 0.27 0.01 0.0 0.0 0.0 0.0
\JJ Ti 32.0 48.0 48.0 0.0 0.0 0.0 0.0 0.0 0.0
(') N V 67 10.0 8.0 1.7 0.3 0.0 0.0 0.0 0.0
»- Yb 0.36 0.053 0.047 0.004 0.002 0.0 0.0 0.0 0.0
Zn 13 1.9 1.4 0.42 0.08 0.0 0.0 0.0 0.0
CI>
Zr 25 3.7 3.3 0.4 0.0 0.0 0.0 0.0 0.0
-i
z
aNonagglomerating coals do not require pretreatment.
bTwo streams are split here: The oil stream is recycled to the
slurry preparation and may accumulate trace elements. The water
stream contains phenols, NH.(F, CI) to be separated, and the
treated water to be recycled. It is important to note that the by-
products may show enrichment of some trace elements.
cThe sour gas from the acid-gas treatment unit is sent to the Claus
plant. It cor-tains much of the acidic compounds of CO2, HzS, .
AszO" 82°,. etc., and fine particulates. Oil is separated durIng
regeneration and is recycled. CO2 is released t~ t.he atmospher.e
with trace sulfur compounds. Some gaseous, aCidic elements, 1. e.,
HzSe and HzTe, will most likely end up in the Claus plant sulfur
product.
dWater is condensed during methanation and may carry away other
trace elements. Almost total sulfur removal is accomplished
during methanation by adsorption onto the catalyst particles. The
product gas will be analyzed for the more volatile, toxic elements,
but not for the innocuous ones.
00
-..D
of>.
\JJ
m
n
:r
o
r-
o
(')
-<
-------
Table 7. CALCLTLA TED FLOW RATES OF TRACE AND MINOR 0:
.......
ELEMENTS IN A HYGAS-BASED, CaMMER CIAL COAL-GASIFICATION - (j
z PLANT USING MONTANA LIGNITE
(J'>
-I
Stream Oxygasifier Hot Oil Waterb Acid-Gas Sulfur Methanationd Product
a EffluentC
-I Description Feed Coal to Slurry Feed System Char Quench Scrub Guard Condensate Gas
C Stream Number C G K 12. 13 11. 14 P 6 9
-I
m * kg/s (X 10])
Element -ppm- kg/s (X 10')
Sb 1.2 0.21 0.16 0.04 0.01 0.0 0.0 a.o 0.0
As 18 3.2 1.5 0.79 0.42 0.49 0.0 0.0 0.0
Ba 1300 230.0 230.0 0.0 0.0 0.0 0.0 0.0 0.0
0 0.98 0.17 0.13 0.04 0.0 0.0 0.0 0.0 0.0
Be
" Bi 0.72 0.13 0.073 0.051 0.006 0.0 0.0 0.0 0.0
B 85 15. I 10.8 3.8 0.5 0.0 0.0 0.0 0.0
Cd 0.72 0.13 0.06 0.056 0.014 0.0 0.0 0.0 0.0
'-H Ca 17,000 3010.0 3010.0 0.0 0.0 0.0 0.0 0.0 0.0
G') W Cl 180 32.0 16.8 1.0 14.2 0.0 0.0 0.0 0.0
> Cr 14 2.5 1.9 0.6 0.0 0.0 0.0 0.0 0.0
(J'> Co 4.4 ,. 0.78 0.78 0.0 0.0 0.0 0.0 0.0 0.0
Cu 8.8 1.6 1.1 0.5 0.0 0.0 0.0 0.0 0.0
F 71 12.6 8.0 1.5 1.6 1.5 0.0 0.0 0.0
Ge 2.7 0.48 0.37 0.04 0.03 0.03 0.01 0.0 0.0
Fe 9200 1630.0 1630.0 0.0 0.0 0.0 0.0 0.0 0.0
-I o. Ii
Pb 1.9 0.34 0.18 0.05 0.00 0.0 0.0 0.0
m Li 5.8 I. 03 I. 03 0.0 0.0 0.0 0.0 0.0 0.0
() Mg 5800 1030.0 1010.0 14.0 6.0 0.0 0.0 0.0 0.0
:I: Mn 8.9 1.6 1.5 0.1 0.0 0.0 0.0 0.0 0.0
Hg 0.73 0.13 0.0013 0.057 0.043 0.028 0.007 0.0 0.0
Z 0.37 0.33 0.04 0.0 0.0 0.0 0.0 0.0
Mo 2. 1
0 Ni 23 4.1 3.7 0.4 0.0 0.0 0.0 0.0 0.0
I N 9200 1630.0 266.0 92.0 1200.0 60.0 11. 0 1:0 0.0
K 340 60.2 58.4 0.8 0.0 0.0 0.0 0.0 0.0
0
Sm 0.51 0.0903 0.089 o. 0013 0.0 0.0 0.0 0.0 0.0
G') 00
...0
* >!:>-
-< Parts Der million W
-------
Table 7, Cont. CALCULATED FLOW RATES OF TRACE AND MINOR
ELEMENTS U: A HYGAS-BASED, COI'v1MERCIAL COAL-GASIFICATION
PLANT USING MONTANA LIGNITE
z
Stream a Oxygasifier Hot Oil Water, -A.::i:! '::a.:: .5uiiur Methanationd Product
UI DescriDtion J;'pp~ ~n::lll t" .C;;:I0~~~:r =~~= 5';::~=~ Cnar ~ Scrub" EffluentC Guard C"ndensate Gas
-t Stream Number C G K IZ, 13 11,
14 P 6 9
-t
C Element -ppm- kills (X 10)) 'kg/. (X 10)
-t Se 1.7 0.3 O. I 0.04 0.08 0.08 0.0 0.0 0.0
m Si 13,000 BOO.O 2125.0 175.0 0.0 0.0 0.0 0.0 0.0
Ag 0.24 0.043 0.041 0.0015 0.0005 0.0 0.0 0.0 0.0
Na 180 31. 9 30.1 1.8 0.0 0.0 0.0 0.0 0.0
Sr 350 62.0 40.7 21. 3 0.0 0.0 0.0 0.0 0.0
o S 9900 1750.0 584.0 70.0 100.0 990.0 6.0 0.0 0.0
Te 0.42 0.074 0.042 0.027 0.003 0.002 0.0 0.0 0.0
'TI 1.9 0.34
Sn 0.32 0.02 0.0 0.0 0.0 0.0 0.0
Ti 320 57.0 57.0 0.0 0.0 0.0 0.0 0.0 0.0
V 67 12.0 9.6 2.0 0.4 0.0 0.0 0.0 0.0
W Yb 0.36 0.064 0.0045
C) ,j:>.. 0.057 0.0025 0.0 0.0 0.0 0.0
Zn 13 2.3 1.7 0.51 0.09 0.0 0.0 0.0 0.0
~ Zr 25 4.4
3.9 0.5 0.0 0.0 0.0 0.0 0.0
UI
-t
aNonagglomerating coals do not require pretreatment.
m
bTwo streams are split here: The oil stream is recycled
to the slurry preparation and may accumulate trace elements.
The water stream contains phenols, NH. (F, Cl) to be
separated, and the treated water to be recycled. It is
important to note that the by-products may show enrichment
of some trace elements.
n
:I:
z
o
cThe sour gas from the acid-gas treatment unit is sent to the
Claus plant. It contains much of the acidic compounds of COl.
HzS, AsZO). BZO)' etc., and fine particulates. Oil is separated
during regeneration and is recycled. COz is released to the
atmosphere with trace sulfur compounds. Some gaseous,
acidic elements, i. e.. HzSe and HzTe, will most likely end up
in the Claus plant sulfur products.
~ater is condensed during methanation and may carry away
other trace elements. Almost total sulfur removal is
accomplished during methanation by adsorption onto the
catalyst particles. The product gas will be analyzed for the
more volatile, toxic elements. but not for the innocuous ones.
(X)
-.0
~
W
r
o
C)
-<
-------
8/76
8943
The term "trace element" usually applies to concentrations of 1000 ppm
or less. Minor elements occur in quantities froni 1000 ppm (0.1%) to several
percent. The major constituents in coal are those typically included in the
ultimate analysis. - carbon, hydrogen, oxygen, nitrogen, sulfur, and ash.
Because of its environmental importance and ubiquity in coal, sulfur is
considered a major component, thoughits concentration can vary from low
to several percent.
The concentration of the trace and minor elements listed in Tables 4 and
7 were determined at IGT from composite samples of the two coals. The
information in Table 6 was approximated from the data in Table 7. The data
represent average values; however, a literature survey of the extent of trace
elements in coals has shown a concentration range of about:!: I order of
magnitude. Thus, depending upon the coal source, the concentration of the
trace elements may be about 10 times more or less than what is recorded
here. Relative to their crustal abundance, or "clarke" value, only boron,
cadmium, and selenium are enriched in coal, while fluorine, manganese,
and phosphorus are at lower levels.
The question of trace-element accumulation in process streams becomes
more complex and obscured beyond the severe partitioning effects (volatile
element-refractory element segregation) of the hydrogasifier and steam-
oxygen gasifier units. An example would be the levels of trace elements
dissolved in the scrubbing media. As this media is reprocessed and re-
cycled to the system, quantities of soluble elements may accumulate.
When the solubility limit for a particular compound (or element) is exceeded,
the excess will precipitate out and be removed as sludge material. The
flow rate of a trace element may fluctuate somewhat with variations in the
feed coal concentration; however, the solubility limit is the highest attainable
level for the element in the recycled medium.
35
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8943
VARIABILITY OF OPERATING CONDITIONS
Th,~ effect of a change in operating conditions. on the fate of trace
elements during gasification will be dealt with in this report section. By
utilizing an IGT computer program that simulates the major hydrogasifier
and steam oxygen gasifier reactions, it is possible to follow trends in the
raw gas com.?osition due to variations in operating conditions without using
the ach.al equipment. Some of the parameters which may be altered in a
computer investigation include the steam/oxygen ratios, coal feed/ steam
ratios, the incorporation of either an electrothermal gasifier or steam-
oxygen ,5asifier operations into the system, etc. (See Appendix B.) The
benefits of this kind of analysis are obvious: Changes in operating condi-
tions can be analyzed in a short time, fewer operators are required, con-
siderab:.y less expense is involved, and no materials are consumed.
Th€: HYGAS Process normally operates at about 6985 to 8275 kN/m2
(1000 to 1200 psia), and the high-temperature and steam-oxygen gasifiers
operate at roughly l210K and 13 OOK, respectively. If residence times are
assumed to be constant, the other important changes that may occur in the
reactor operating conditions are those of temperature and press':!re.
In t1.e computer simulations, the effects of different reactor pressures
and tem:?eratures on raw synthesis gas compositions were examined.
In
order to gauge what may result from any uncontrolled temperature fluctua-
tions in the reactor, a range of :!: 20'70 of the normal operating condition was
used. Thus, as the normal operating temperature of the steam-oxygen
gasifier is 1300K, the computer test values were set at extremes of 1560K
and 108CK. The corresponding temperatures in the low and high-temperature
reactors were obtained from the computer program. To evaluate the effects
of di££er(~nt operating pressures, test values ranged from 9930 kN /m2 (1440
psia, + 2,010) down to 1825 kN/m2 (265 psia, -78'10).
In a commercial plant, automatic feedback (or feed forward) controls
should b~ able to maintain a relatively close regulation of process tempera-
ture and pressure during steady-state operation. The widest range of
proces s fluctuations will probably be experienced during the start-up
sequence. As this process may continue over several days, the by-product
streams from the plant should be closely monitored for unusual contaminants
36
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o F
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8943
for the duration. In any system, a major upset may cause severe strains
on the water or gas treatment facilities.
The key indicator in such a study is to what extent the operating regions,
des cribed previously, change due to alterations in reactor temperatur e and
pressure. That is, for a change in temperature (or pres sure), what magni-
tude of variation is observed for the values of operating region indicators -
log (PH,O/PHzS)' etc. These factors are the gauges by which the more
stable forms of an element may be determined.
Table 8 contains the output data from computer runs on Illinois No.6
seam bituminous coal using standard conditions but several variations of
pressure and temperature. Column A presents the synthetic raw gas com-
positions for standard operating conditions. Column B reflects a low-pressure,
high-temperature variation. Column C shows high-pressure, high-temperature
output. When a low-pressure, low-temperature simulation was attempted,
however, the com;mter rejected the set of conditions. The temperature was
obviously too low to sustain the gasifier reactions. Columns D, E, and F
are standard temperature runs with low-pressure variations. Column G
contains output for a standard condition run for Montana subbituminous
coal. The final column (H) contains the calculated raw gas composition
using a lignite coal.
As the data of Table 8 indicate, the raw gas compositions vary consid-
erably with changing operating conditions for the same coal.
Yet if one
compares several examples and calculates the values for the operating
regions, the variations do not represent major changes in the thermodynamic
driving force. This is shown in the tabulation given below. The figures are
based on calculations using the Ideal Gas Law and carry some uncertainty.
In the examples using Illinois No.6 bituminous coal, the HzS concen-
tration ranges from a low of 0.89 mol'7o (Column A, steam-oxygen gasifier)
to 1.30 mol'1o (Column D, electrothermal gasifier). Depending upon the
reaction thermodynamics, this difference mayor may not affect the ultimate
form of the element in a changing system. Consider these two typical gas-
phase (heterogenous) reactions.
MO(s) + H2 (g) :;, M(s) + H20 (g), log. K
eq
+- .'
MO(s) + H2S(g) .. MS(s) -I- H20(g), log K
. eq
=2.0 (1)
= 1.2 (2)
INSTITUTE
o F
37G A S
TEe H N 0 LOG Y
-------
z
(II
-I
-I
C
-I
m
o
."
C"I
>
(II
-I
m
()
:r
z
o
r
o
C"I
-<
Table 8. COMPUTER-CALCULATED COMPOSITION OF HYGAS REACTOR RAW
SYYTHESIS GAS FOR VARIOuS TEMPERATURES AND .PRESSURES
CX>
---
-J
0'
A D C D E F G
SliLnda rd d HiSh d Hil!h !;tauda ru StiLod4rd StandiLrd StandiLrd
Temper.ture, Temper.tL1re, Temperature, Temperature, Temperaturu, Temperatu.re, Temp~rature,
Pre.8L1re Low Preoour. Low Low Low Predsure
Proasure Pres.ufo Pre..ure Pre..ure
Coal Type Illinoio No. 6 Bituminouo PiUaburah b
Montana
BltumiDouo Subbituminoua
Component mol 1.
CO 19.45 2 I. 63 19.89 31. 1Z 23.93 19.9l 14.21
Co. 20.09 18.92 20.17 6.95 15.94 17.70 20.31
1\ 21. 01 25.63 22.68 39.09 28.32 24.38 19.85
1\0 22.98 23.59 24.28 9.08 19.92 22.97 30.111
Clio 14.88 8.62 11. 34 9.99 9.71 12.83 13.26
CaH. 0.28 0.26 0.27 0.76 0.52 0.52 1. 03
C,H, 0.09 0.08 0.08 0.25 0.17 0.17 0.16
NH. 0.33 0.30 0.31 0.58 0.39 0.40 0.311
H,S 0.89 0.97 0.98 I. 30 0.90 0.90 O.ll
'N Na 0.00 ~ ~ ~ ~ ~ ~
(X)
100.00 100.00 100.00 ?9.17 a 99.83 a a a
99.83 ".63
H
StiLndiL rd
Temperature,
Pressure
Lianite
12.89
19.49
22.14
35. 39
8.89
0.40
0.20
0.40
0.20
100.00
Operating Conditione
Low.Temperature Reactor, K 950 1140 1140 880 965 910 900 950
Hlah-TemperOLture Reactor, K IllO 1450 1450 lZ28 1210 1210 1200 1210
o..Yllulfler, K 1300 1530 Q 1300 1300 1300
lS30 1310 1300
Preo.ure. kN/ m' 8275 6618 9930 1825 3620 5620 8065 6895
(ll00 pela) (960 pala) (1440 paliL) (265 poiiL) (525 peia) (815 poia) (1110 poia) (1000 pala)
~lncludes small quantity of new oil make material.
bs..Uur content, 0.66'70; moieture, l2.01..
c J4ectro-thermal ga.iller.
d1'he terms standard temperature oz 8tandard presliure refer to the operatinK conditions in the steam-oxygen gasifier.
and eundard preaaure ie B275 k.N/m' (1200 paia) In the eteam-oxygen guifier. '
The corresponding temperaturel of the low...and high- temperature reactorl were obtained from the computer proKram.
B750l0225
Standard temperature 10 BOOK (IB80'F)
00
-..0
>J:>.
IoN
-------
A B C D
Standard High T, High T, Standard T,
Operating Conditions Temperature, Pressure Low P High P Low P
*
Temperature, K 1300 1530 1530 1310
Pressure, kN Imz 8275 6620 9930 1825
(psia) (1200) (960) (1440) (265)
Operating Regions
(1) log[PHzOIPHz] 0.04 -0. 04 0.03 -0.63
(2) log[PHzOIPHzS] 1. 41 1. 39 1. 39 0.84
*
Electrothermal gasifier.
Note that the numerical difference between log K (2.0) and the Operating
eq
Region (s ee above values), which is the thermodynamic driving force for
Equation 1 may be from 1.96 (Column A) to 2.63 (Column D). The driving
force does not undergo a sign change, nor a significant change in magnitude,
thus the expected product for this reaction is M (s).
For Equation 2, the thermodynamic driving force ranges from -0.21
(Column A) to 0.36 (Column D). Thus, for a situation in which a gasifier
loses significant system pressure (while maintaining temperature), the new
steady-state operating conditions may cause a reversal of the driving force.
The raw synthesis gas composition would change from the one listed in
Column A (Table 8) to the one listed in Column D (Table 8), with a corres-
ponding change in operating regions. If the magnitude of the driving force
(i. e., log K - Operating Region) is near zero, the ratio of products to
eq
reactants at steady-state will remain unchanged.
Further calculations must be m3.de in order to determine other pos sible
reactions which may forn"! chlorides or hydrides, for example. In general,
it is not expected that altering the temperature and pressure of this system
would change the final distribution of the trace elements significantly.
Some of the minor elements such as nitrogen and sulfur, show variations in
flow quantities which may be of concern downstream during operation of the
purification system.
The assumption of constant residence times is not strictly valid across
the temperature and pressure range discussed. An investigation to determine
the effects of prolonged residence times on trace-elements I volatilization
should be undertaken. It is likely that some trace-element losses may be
proportional to residence time.
39
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The temperatures which have been used in the computer analyses are
averages over the entire fluidized reactor bed volume. They do not address
the possibility that localized hot spots may exist in the steam-oxygen gasifier,
above the oxygen sparger. Thes e hot spots may be several hundred degrees
hotter than the surrounding areas and thus, enhance the volatilization of
some, otherwise refractory trace elements.
The effects of these hot spots
on trace-element distribution are not well understood and may be significant.
Furthe:~ investigation is neces sary.
40
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SAMPLING
Sampling Points
The sampling points described in Table 9 and shown in Figure 2 refer
to locations at the HYGAS pilot plant that will yield the most useful informa-
tion concerning trace-element distribution in a commercial-size coal gasi-
fication plant. It must be emphasized, however, that significant calculations
and engineering estimates must be made in order to extrapolate from pilot-
to commercial plant- scale.
Table 9 includes actual, operational data on the temperature, pressure,
and flow rates of the pilot-plant proces s streams. The type of sample
required at each location is indicated to the right of the listing. Figure 2
identifies each sampling point with respect to other process units and also
gives the concurrent phase or phases to be sampled. In this test plan, some
typical solid-waste streams are to be sampled as slurries (SL) for both
solid and liquid phases. The high pressures encountered in the HYGAS
Proces s require that all solid streams be slurried with water prior to dis-
charge. Thus, the material sampled from the primary cyclone (Sample
Location 4) will include the effluent slurry medium (L) as well as the parti-
culate matter (S). Care must be taken during sampling and analysis, to
account for water soluble constituents of slurry discharge as well as the
constituents contained in the solid residues.
Similarly, typical liquid effluent streams will be tested for particulate
matter, which may accom?any the liquid by entrainment or by incomplete
phase separations. The product gas stream (Sample Location 11) will be
sampled to determine if any of the more volatile trace elements have sur-
vived the numerous gas -cleaning steps. The pretreater (Sample Location 12)
produces solid, liquid, and gaseous effluents. This stream is expected to
harbor much of the more toxic, volatile elements; hence, their analyses
should be of considerable interest.
The base-line data points for the quench water, and toluene
washes should be established early in the test program, as some trace
elements may tend to accumulate in the reactor through a volatilization,
41
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Table 9.
8943
HYGAS PILOT PLANT SAMPLING POINTS
Sample Description
1.
Raw Coal
Ambient Conditions
2.
P ~etreated Coal (char)
0.75 kg/s (6000 lb/hr)
7000K (800°F)
I I 5 kN / m 2 (2 psi g )
3.
Light Oil (Toluene)
2.268 kg/s, (18,000 Ib/hr)
Ambient Temp, Pres sure
4.
C\fclone Fine s
0.126 kg/s (1000 lb:hr)
6450K (700°F)
6895 kN/m2 (1000 psia)
5.
A:;h From Oxygen Gasifier
0.1327 kg/s (10'53 lb/hr)
10900K (I 500°F)
6930 kN/m2 (100'1 psi a)
6.
Char Slurry From Prequench Tower
0.52 kg/s (41..10 Ib/hr)
408°K (275°F)
6865 kN/m2 (996 psia)
7.
Q1.lench Water to Quench Tower
7.938 kg/s (630001h/hr)
3100K (99°F)
6825 kN/mz (990 psia)
8.
Npt Toluene to Storage
2.261 kg/s (179-l-l1b/hr!
3150K (llOOF)
682'5 kN/mz (990 psia)
9.
WOlter Scrub Influent (Base)
Water Scrub Effluent
10.
Acid Gas From Acid-Gas Treatment
0.383 kg/s (3039lb/hr)
3330K (140°F)
117 kN / m2 (17 psia)
11.
PJ'oduct-Gas Stream
0.0693 kg/s (550 lb/hr)
3100K (l00°F)
6275 kN/m2 (910 psia)
12.
Pretreatment Off-Gases, Tars, Oils
Ambient Conditions
INSTITUTE
o F
Sample Phase
Solid
Solid
Liquid
Slurry
Slurry
Slurry
Liquid
Liquid, Solid
Liquid
Liquid, Solid
Gaseous
Gaseous
Solid, Liquid, Gaseous
4.2:.
GAS
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8943
condensation, and revolatilization process. A similar recycling of trace
elements may occur in the slurry system. The levels of these accumulations
should be measured periodically in the sampling program to determine if
steady-state levels are attained.
The distribution of certain elements, such as nickel or vanadium, that
may plate out on process-unit walls, could be estimated more closely by
positioning test coupons in the process gases. However, such a procedure
would be somewhat academic, as both vanadium and nickel should appear
in the ash or in the entrained particulates from the quench towers, thus
reducing the pollution concern.
The pilot plant is, of course, not of commercial size; its capacity is
roughly 0.78 kg/s (75 tons/day). Not all of the process units required in a
commercial plant are in operation at present. As the by-product recovery
units come on-stream, however, the analysis of trace elements can be ex-
tended to include each by-product. Much will be revealed about the efficiency
of the recovery units as well as the salability of the by-product itself.
Not all of the HYGAS pilot-plant process units relate directly to the
example of a HYGAS-based commercial design, as presented in Figure 1.
For example, the pilot plant utilizes a prequench tower prior to quenching,
and the quench liquor is water rather than a cool oil. The cyclone fines
are discarded at pres ent and not recycled as they would be in the proposed
commercial plant. The steam plant at the pilot plant is gas -fired, not coal-
fired, as presented.
The levels of trace constituents in each of the process streams can be
determined from the data of Tables 4, 6, and 7.
Since the flow rates of these
tables are based on a commercial-sized coal facility, each m'.lst be scaled
down to correlate with the lower flow rates of the pilot plant. Depending
upon the f.eed coal, the capacity of the HYGAS pilot plant is from 233 to 346
times less than the corresponding commercial-size plant. (See Appendix
C for the basis of these factors. )
43
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With scaling factors of such magnitude, it is imperative that each sample
taken -)e representative of the lot,and that sufficient numbers of samples be
analyzed to ensure that the results have statistical significance.
To maintain sample consistency, standard methods of solid, liquid,
and gaseous sampling have been selected from ASTM procedures. Statis-
tically significant results will be attained by sampling each location frequently
(~ 20 ttmes) over the cours e of a 7 -day, steady-state, performance-evaluation
period.
Sampling Techniques
Solid Samples
These include both dry, solid discharges and water-slurried, solid
discha:rges. Each will be collected and prepared according to ASTM Methods,
D-223~:-72, "Sampling of Coal" and D-20J 3-72, "Preparing Coal for Analyses, II
respectively.
Liguid Samples
Ar.. integral part of the liquid-sampling plan is to obtain flow information
on varjous in-plant streams as well as on the plant outfall to facilitate com-
pletion of the following tasks:
Tbe characterization of flow rates of waste water and other liquid
effluents as well as variations in them caused by process upsets
The determination of the total amounts of each constituent emitted
frclm each stream bas ed on the analytical data and the determined
flow rate
The calculation of the solid and liquid mass balances based on the
analytical data gathered for these two kinds of sample analyses
Proces s stream flow rates can be approximated by the following methods:
1) water meters on effluent lines, 2) container and stopwatch, and 3) salt
concentration. The details of these and alternative measuring methods can
be found in many references. 65, 66 One or more of them should be us ed in
conjunction with operating parameters available from HYGAS pilot-plant
record~.
44
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Some analytical parameters of the liquid sample, such as the pH and
temperature, should be measured at the time of sampling. Other analytical
tests require that the sample be chemically fixed immediately after collection.
This is done to reduce the degradation of certain organic or inorganic con-
stituents in the sample, which may occur during shipping and storage.
Common analytical determinations that require special sample fixation,
their maximum holding time before chemical analyses, and the proper
types of containers for collection, are given in Table 10. Separate samples
are needed for analytical tests, which require that the sample be fixed with
different preservatives.
Gaseous Samples
Gaseous sampling systems will be set up following the ASTM atmos-
phere-sampling method. "Standard Recommended Practices for Sampling
Atmosphere for Analysis of Gases and Vapors, II D-1605, Part 23, and the
"Standard Method for Sampling Stacks for Particulate Matter," D-2928,
Part 23 - ASTM standard methods - will be correlated into one sampling
system.
The particulate matter will be collected on a 47 -mm filter, and the
gases and the vapors passing through the filter will be collected in a freeze-
out sampling train consisting of a series of traps at progressively lower
temperatures. The refrigerant should be sufficiently cold to ensure that the
vapor pressure of any trapped material will be low enough to prevent signi-
ficant evaporation during the sampling.
45
INSTITUTE
o F
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TEe H N 0 LOG Y
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8 /'/6
Holding
Time
None
6-l2hr
24 hr
7 days
6 month 8
Table 10. PARAMETERS RELATING TO PRESERVATION,
HOLDING TIME, AND SAMPLE STORAGE
Parameter
Preservation
pH
Temperature
BODs':'
Mercury
Nitrogen (Total)
Refrigeration, 4°C
None
40 mg HgClz/ t
refrigeration, 40C
Refrigeration, 40C
NaOH to pH> 10
2 ml HzS04/ t
refrigeration, 4°C
1 g CUS04/ t
H) P04 to pH 4
Refrigeration, 40C
None required
2 ml HzS04 (or HC1)
to pH 2
2 ml HzS04
None required
None required
40 mg HgClz/ t,
refrigeration, 4°C
40 mg HgClz/ J"
refrigeration, {oC
40 mg HgClz/ t,
refrigeration, 4°C
None required
Refrigeration, 40C
2 ml Zn acetate/ t
None available
5 ml HN03/ t
Color
Cyanide
Oil and grease
Phenolic s
Odor
Calcium
TOC':'
COD':'
Fluoride
Hardne S8
Nitrogen (NH))
Nitrogen NO), NOz
Phosphorus
Solids
Sulfate
Sulfide
Turbidity
Metals
",
" BOD!; is 5-day biological oxygen demand.
TOC is total organic carbon.
COD is chemical oxygen demand.
46
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
8943
C ontaine r
Glas s or plastic
Glas s or PVC
Glass
Glas s or plastic
Glas s
Glas s
Glas s
Plastic or glass
Plastic or glas s
Plastic or
Plastic or
Plastic or
Plastic or
glas s
glas s
gla s s
gla s s
Plastic or glass
Plastic or glass
Plastic or glas s
Plastic or glas s
Plastic or glass
Plastic or glass
Glas s
-------
8/76
8943
ANAL YTICAL METHODS
Solid Samples
These samples include raw and pretreated coal, coal fines, slurry
solids, and solid by-products. They should be analyzed for trace and minor
constituents. The initial step for most trace-element analysis is ashing of
the solid sample in a low-temperature ash (LTA) plasma machine, with
subsequent dissolution in the proper acid mixture. Due to volatility, some
elements (such as mercury) will be lost during the LT A proces s. As a
result, a duplicate sample will be needed for analysis by an appropriate
analtyical scheme.
The analytical methods to be used for each elemental analysis and
some possible alternative methods are given in Table 11. The actual analy-
tical technique to be used for the determination of each constituent will depend
upon the level of that element in the sample as well as on the possible inter-
ferences due to the pres ence of other elements. A NBS standard reference
coal sample should be concurrently analyzed to ensure the accuracy of the
analys es.
Liquid Samples
These samples include any proces s unit tars and oils, quench liquor,
toluene, recycled waste water, phenols, and ammonia. Some liquid samples
will contain large quantities of solids and organic materials. Aqueous
samples should be tested for BODs, COD, color, oil and grease, TOC, TS,
*
TDS, TSS, and turbidity in the whole sample. 9rganic samples need to be
analyzed for trace elements and organic constituents, specifically polynuclear
*
BODs is the 5-day biological oxygen demand.
COD is the chemical oxygen demand.
TOC is total organic carbon.
TS is total solids.
TDS is total dissolved solids.
TSS is total suspended solids.
47
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
Table Ll, Part 1. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF SOLID SA MPLES .
Detectton c Precision,
Constituent Method Limit Range 'fod
Antimony 1. LTA -acid dis solution a 0.001 ppm 0.04-2 ppm 5
Iodide-benzene extraction
Flameless AAS
2. LTA-acid dissolution a 0.001 ppm 3
Hydride formation
Heated-quartz-cell AAS
Arsenic 1. LTA -acid dis solution a 0 . 0 1 ppm 3.0 -30 ppm 7
Flamele s s AAS
2. LTA-acid dissolution a 0.05 ppm 5
Ion- exchange column
separation
APCD-MIBK extraction
Air-CzHz flame AAS
3. LT A -acid dis solution a 0.001 ppm 7
Ion-exchange column
separation
APCD- MIBK extraction
Flamele s s AAS
4. LTA-acid dissolution a 0.001 ppm 3
Hydride formation
Heated-quartz- cell AAS
Barium 1. HTA -acid dis solution a 0 . 0 1 ppm 20 ppm - 5
NzO-CzHz FES 2%
2. HTA-acid dissolution a 0.001 ppm 4
HzS04 ppt
NH40H-EDTA redissolution
NzO-CzHz FES
3. HTA-NazC03 fusion 65 0.001 ppm 4
Hot-water leaching
HCl dis solution
NzO-CzHz FES
Berylliu!:1 1. LTA-acid dissolution a 0.002 ppm 0.2-2 ppm 7
NzO-CzHz AAS
2. L TA-acid dis solution a 0 . 000 1 ppm 5
Flameles s AAS
Bismuth LTA-acid dissolution a 0.02 ppm 0.2-2 ppm 5
APCD-MIBK extraction
Flamele s s AAS
48
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
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8943
Table 11, Part 2. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF SOLID SAMPLES
Constituent
Boron
Cadmium
Calcium
Chlorine
Chromium
Cobalt
Copper
Fluorine
Germanium
Iron
Lead
Li thium
Method
1.
LTA-NazC03 fusion a
Diol-CHC13 extraction
NzO-CzHz FES
LTA-acid dissolutiona
APCD-MIBK extraction
Air-CzHz flame AAS
LTA-acid dissolutiona
APCD-MIBK extraction
Flameless AAS
2.
LTA-acid dissolutiona
Air-CzHz flame AAS
Eshka-HN03 extraction 65
Amperonietric titration
LTA-acid dissolutiona
Air-CzHz flame AAS
1.
LTA-acid dissolutiona
Flamele s s AAS
LTA-acid dissolutiona
APCD-MIBK extraction
Flameless AAS
2.
LTA-acid dissolutiona
Air-CzHz flame AAS
a
Oxyg en Bomb - SIE
LTA-emission spectro-
graphy
1.
LTA-acid dissolutiona
Air-CzHz flame AAS
LTA-acid dissolutiona
APCD-MIBK extraction
Air-CzHz flame, AAS
LTA-acid dissolutiona
APCD-MIBK extraction
Flameless AAS
2.
LTA-acid dissolutiona
NzO-CzHz FES
49
INSTITUTE
o F
GAS
Detection
Limitb
o . 05 ppm
0.005 ppm
0.0001 ppm
o . 002 ppm
1 ppm
o. 0 1 ppm
o . 00 1 ppm
0.0001 ppm
o . 0 1 ppm
o. 1 ppm
l,ppm
0.005 ppm
o . 0 1 ppm
0.001 ppm
0.001 ppm
c
Range
30 - 500 ppm
O. 1 -10 ppm
1-50 ppm
0.1%-2%
0.01% '"
0.5%
10-500 ppm
1-50 ppm
5-50 ppm
30 - 300 ppm
1-40 ppm
0.2%-5%
2-50 ppm
2-50 ppm
TEe H N 0 LOG Y
Precision,
%d
5
4
5
3
8
4
5
6
3
9
10
2
4
6
3
-------
8/76 8943
Table :.1, Part 3. ANALYTICAL METHODS FOR CHEMICAL ANAL YSIS
OF SOLID SAMPLES
Detectton Precision,
Constitui~nt Method Limit Rang e c %d
Magnesillm LTA-acid dissolution a 0.001 ppm 0.02%"'1% 2
Air-CzHz flame AAS
Manganese LTA -acid dis solution a 0 . 0 1 ppm 5-100 ppm 3
Air-CzHz flame AAS
.Mercury Total combustion - o. 1 ppb 0.01- 5 ppm 10
KMn04a
Cold vapor flameless AAS
Molybdenum LTA-acid dissolution a 0.005 ppm 1 - 10 ppm 6
Flameles s AAS
Nickel LTA-acid dissolution a 0.01 ppm 10-50 ppm 4
Air-CzHz flame AAS
Nitrogen KJeldahl digestion -
titrationI
Potas siurn LTA-acid dissolution a 0.001 ppm 0.02%-0.2% 3
Air-CzHz FES
Samariurn LTA-emission O. 5 ppm 0.2-2 ppm 10
a
spectrography
Selenium 1. LTA-acid dissolution a 0 . 0 1 ppm 0.1-50 ppm 6
Flameless AAS
2. LTA-acid dissolution a 0.001 ppm 5
Ion- exchange column
separation
APCD- MIBK extraction
Flameless AAS
Silicon 1. LT A -gravimetric O. 1 mg 1 % -5 % 2
methoda
2. LT A -acid digestion O. 1 ppm 3
bomba
NzO-CzHz flame AAS
Silver LTA-acid dissolution a 0.001 ppm O. 1-5 ppm 6
Flameless AAS
Sodium LTA-acid dissolution a 0.005 ppm 0.01 '" 3
Air-CzHz FES O. 2 ppm
50
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/7.6 8943
Table 11, Part 4. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF SOLID SAMPLES
Detection Precision,
Constituent Method Limitb Range c %d
Strontium LTA-acid dissolution a 0.001 ppm 10.,;500 ppm 3
NzO-CzHz FES
Sulfu r Eshka-gravimetric 0.1 mg 0.1% '" 5% 2
method 1
Tellurium 1. LT A -acid dis solution a 0.01 ppm 0.1 '" 10 ppm 6
Flameless AAS
2. LTA -acid dis solution a 0.001 ppm 5
Ion-exchange column
separation
APCD-MIBK extraction
Flamele s s AAS
Thorium LTA-acid dissolution a 0.02 ppm O. 1 '" 5 ppm 6
Ion-exchange column
separation
Colorimetric method
Tin 1. LTA-acid dissolution a 0.01 ppm O. 1 '" 5 .ppm 6
Iodide-isopropyl/ ether
extraction
Flame1ess AAS
2. LTA-acid dissolution a O. 0 1 ppm 5
Hydride formation
Heated-quartz-cell AAS
Titanium LTA-acid dissolution a O. 1 ppm 0.01%'" 4
NzO-CzHz flame AAS 0.1%
Vanadium 1. LTA-acid dissolution a O. 2 ppm 10 -100 ppm 10
NzO-CzHz flame AAS
2. LTA-acid dissolution a 0 . 0 1 ppm 5
Ion- exchange column
separation
APCD-MIBK extraction
NzO-CzHz flame AAS
Ytterbium LTA-emission O. 1 ppm O. 1-1 ppm 10
a
spectrography
51
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
Table :[1, Part 5 . ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF SOLID SAMPLES
Detection Presicion,
Constituent Me thod Lirnitb Range c %d
Zinc LTA-acid dissolution a O. 0 1 ppm 5-100 ppm 6
Air-CzHz flame AAS
Zirconium LTA-emission 1 ppm 10-100 ppm 10
a
spectrography
A bbrevic:.tions:
AAS -- Atomic absorption spectrophotometer
APCD - Ammonium pyrrolidine carbodithioate
Diol -- 2-ethyl-l, 3-hexanediol
EDTA - Ethylenediamine tetraacetic acid
FES -. Flame emission spectrophotometer
HTA -. High-temperature ashing
LTA-' Low-temperature ashing
MIBK - Methylisobutyl ketone
SIE - Selective ion electrode.
Notes:
a
Methods cur rently in use at IGT.
b
Detection limits are estimated as the concentration of the constituent in
the sample solution or mixture that would produce a signal twice as large
as the background noise level. In gravimetric methods, detection limits
are expressed as the minimum weight the balance can accurately weigh
(0. 1 mg in IGT I S Analytical Laboratory).
c
The range refers to the estimation of the constituent concentration in the
sample.
d
Precinions are estimated by applying the specified analytical method to
the sample in the estimated range.
52
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
aromatics.
Any emulsified samples should then be separated into three
portions - organic, aqueous, and solid -by filtration and solvent extraction.
The solid portion of the sample should be analyzed for trace and minor
constituents and t;reated as any other solid sample. A measured portion
of the organic phase of the sample should be evaporated carefully, wet-
ashed, and also analyzed for trace elements. The aqueous portion of the
sample will be analyzed for the parameters listed in Table 12. EPA reference
water samples will be analyzed concurrently to ensure the accuracy of the
measurements.
Gas eous Samples
The entrained particulate matter in gas should be separately recovered
by filtration and analyzed for trace elements using the analytical methods
for solid samples. The gases and vapors collected in the freeze-out apparatus
will be combined and analyzed according to the methods given in Table 13.
We expect that considerable water vapor will condense and freeze from samples
taken from Sample Location No. 12, pretreater off-gases. The volumes
of water can be reduced by preconcentration of the samJ?les to render
them .more manageable for analysis. In addition, provisions should be
made to recover and determine the concentration of polynuclear aromatics
in the effluents of all the stacks in the plant.
53
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
Table ]2, Part 1. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF LIQUID SAMPLES
Parameter
BOD,S Days
COD
Chloride
Color
Cyanide
Mercaptans
Metal ~
Aluminunl
Antimony
Ar senic
Barium
Method
Modified6~i71fJser or Probe
Method -
65'67'68
Dichromate reflux
Detection
Limitb
60 ppm
50 ppm
Amperometrical titration6S, 67' 68 1 ppm
PI . b It' -1-67'-68
atlnum-co a Vlsua-
1 D't'I-It' 'I 65'67'680.1ppm
. IS 1 a Ion - Sl ver -
nitrate titration
2. Pyridine pyrazoione
coiorimetric65' 67' 68
3 . SIE
GC - photometric
a
ddector
1. NzO-CzHz flame AAS68
a
2. NzO-CzHz FES
1. Air - C zHz flame AAS
2. Hydride formationa
Heated-quartz- cell AAS
1. Silver diethyidithiocar-
bonate3
2. Air-CzHz flame AAS~
3. APCD-MIBK extractiona
Air-CzHz flame AAS
4. APCD-MIBK extractiona
Flameless AAS
5. Hydride formation a
Heated-quartz-cell AAS
6(;
1. NzO-CzHz flame AAS-
a
2. NzO-CzHz FES
54
INSTITUTE
o F
GAS
0,01 ppm
o . 0 1 ppm
O. 1 ppm
0.001 ppm
O. 1 ppm
o . 00 1 ppm
o . 0 1 ppm
O. 1 ppm
o . 0 1 ppm
0.00 I ppm
.001 ppm
0.05 ppm
0.001 ppm
c
Range
Precision,
%d
NA
2000 '"
50,000 ppm
30-500 ppm
O. 1 '" O. 6 ppm
NA
NA
0.001
-D.OOS
O. 028 -
0.044 ppm
O. 0 1 - O. 1 ppm
O. 11 '"
O. 16 ppm
TEe H N 0 LOG Y
20
10
5
30
4
5
NA
3
2
5
5
3
30
3
-------
8/76 8943
Table 12, Part 2. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF LIQUID SAMPLES
Detection Precision,
Metals Method Limitb Range c %d
Beryllium 1. 6a 0.001-
NzO-CzHz flame AAS. 0.002 ppm
O. 1 ppm
2. a O. 1 ppb 4
F1ame1ess AAS
3. Solvent extraction a 0.01 ppb 5
F1ames1ess AAS
Boron Curcumin colorimetric 67 0.2 ug 0.05- 5
10 ppm
Cadmium 1. Air-CzHz flame AAS 68 0.005 ppm 0.4- 1 ppb
2. a 0 . 05 pp b 5
F1ame1e s s AAS
3. APCD-MIBK extraction a 0.005 ppb 7
F1ame1ess AAS
Calcium Air-CzHz flame AAS68 0.002ppm 3.6-4.4ppm 3
10-200 ppm
Chromium 1. Air-CzHz flame AAS68 0.005 ppm NA 3
2. F1ame1ess AASa 5 ppb 5
C obaIt 1. ' 68 0.005 ppm 1-2 ppb
Au-CzHz flame AAS
2. APCD-MIBK extraction a 0.5 ppb 30
Air-CzHz flame AAS
3. APCD-MIBK extraction a 0.01 ppb 6
F1ame1ess AAS
Copper 1. Air-CzHz flame AAS68 0 . 005 ppm 0.016- 20
0.020 ppm
2. APCD-MIBK extraction a 0.5 ppb 5
Air-CzHz flame AAS
Iron 1. ' 68 0.005 ppm 2.6-2.9ppm 3
Au-CzHz flame AAS
2. APCD-MIBK extraction a 0.5 ppb 5
Air-CzHz flame AAS
55
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/71>
8943
Table 12, Part 3. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF LIQUID SAMPLES
Metals
Lead
Fluoride
Ge rmanium
Magnesium
Mercury
Molybdenum
Nickel
Potas siurn.
Selenium
Silver
Sodium
Strontium
Method 1
1. Air-CzHz flame AAS68
2. APCD-MIBK extractiona
A.ir-CzHz flame AAS
3. Flameless AASa
SIE
68
1. NzO-CzHz flame AAS
a
2. NzO-CzHz FES
3. Hydride formationa
Heated-quartz- cell AAS
Air - CzHz flame AAS68
Cold-vapor flameless
AASa,68
NzO-CzHz flame AAS.68
1. Air-CzHz flame AASa,68
2. APCD-MIBK extractiona
Air-CzHz flame AAS
1. Air-CzHz flame AAs68
2. Air-CzHz FES65
1. Air-CzHz flame AAS68
65
2. Flamele s s AAS
1. Air-CzHz flame AAS 68
2. Flameless AASa
1. Air-CzHz flame AAS68
2. Air-CzHz FES"
1. Air-CzHz flame AASf>8
a
2. NzO-CzHz FES
56-
INSTITUTE
o F
GAS
Detectign
Limit
o . 03 ppm
0.003 ppm
O. 1 ppb
O. 1 ppm
2 ppm
O. 5 ppm
o . 005 ppm
0.01 ppb
0.01 ppb
0.05 ppm
0.005 ppm
0.05 ppb
0.005 ppm
O. 5 ppb
o . 3 ppm
0.001 ppm
0.005 ppm
0.05 ppb
0.002 ppm
0.05 ppb
o . 0 1 ppm
O. 1 ppb
c
Range
0.01-0.1 ppm
0.032 -
0.061 ppm
1. 5-1. 8 ppm
0.4 - 5ppb
NA'
0.023 .-v
0.034 ppm
O. 1 .-v 0 . 2 ppm
O. 3 .-v O. 4 ppm
0.001.-v
0.05 ppm
NA
NA
o . 0 24 '"
0.033 ppm
TEe H N 0 LOG Y
Preci~ion,
%
10
5
5
6
2
5
3
20
10
3
2
6
3
6
3
2
20
3
-------
8/76
Table 12. Part 4. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF LIQUID SAMPLES
Metals
Tellurium
Tin
Vanadium
Zinc
Zirconium
Parameter
Nitrogen
(Ammonia)
Nitrogen
(Nitrate)
Nitrogen
(Nitrite)
. Nitrogen
(Total)
Oil and
Grease
Method
1. Air-CzHz flame AAS~8
2. Flameles s AASa'
1. Air-CzHz flame AAS68
a
2. Flameles s AAS
a 68
1. NzO-CzHz flame AAS .
2. APCD-MIBK extractiona
NzO-CzHz flame AAS
3. APCD-MIBK extractiona
Flameless AAS
1. Air-CzHz flame AAS68
2. APCD-MIBK extractiona
Air-CzHz flame AAS
68
NzO-CzHz flame AAS
1. Distillation nes sleri-
t. 65' 67' 68
za Ion
2. SIEa
1. Brucine sulfate65' 67' 68
2. SIEa
Diazotization colori-
t . 65' 67' 68
me rIC
Digestion - distil-
l . 65' 67' DB' . and
ahon
titration
Liquid-liquid 6 6
. 65, 7' 8
extractIon
57
INSTITUTE
o F
GAS
Detection
Lirnitb
O. 1 ppm
0.001 ppm
0.06 ppm
o . 00 1 ppm
0.02 ppm
o. 002 ppm
0.2 ppb
0.002 ppm
00 2 ppb
5 ppm
0.05 ppm
0.01 ppm
o . 2 ppm
1 ppm
o . 05 ppm
o . 05 ppm
0.5 mg
c
Rang e
0.001 '"
0.05 ppm
0.016 -
0.020 ppm
0.002 -
0.004 ppm
0.044 -
0.083 ppm
NA
2500 '"
11.000ppm
NA
NA
NA
NA
TEe H N 0 LOG Y
8943
Preci~ion.
%
8
8
10
8
6
3
10
4
20
NA
NA
4
NA
-------
8/76
8943
Table 12, Part 5. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF LIQUID SAMPLES
Detection Precision,
Paramet,~r Method Limitb Range c %d
Phenolic 3 1. Colorimetric method65' 67' 6~ ppm 7.00- 6600 ppm 4
2. GC":" hydrogen flame 1 ppm 4
d t t 65 67' 68
e ec or .
3. GC - MSa 1 ppm NA
Polynucl'~ar - Solvent NA NA NA
Aromatics Extraction, GC -MS
Sulfate 1. Tur bidimetri c 4 ppm NA 6
method65' 67' 68
2. SIEa O. 1 ppm 6
Sulfide 1. T . . t' . h d 65' 67 , 68 1 NA NA
Itnme rlC met 0 ppm
2. SIEa 0 . 0 1 ppm 5
Thiocyanate Colorimetric methoda O. 1 ppm 20-1000 ppm 5
Turbidity Turbidimetric 1 Jackson NA. NA
method65' 67' 68 unit
TS Gravimetric, 10 50C 65' ~1' 680.5 mg NA NA
TDS G1as s fiber filtration, 1 mg NA NA
180oC65' 67' 68
TSS G1as s fiber filtration, 1 mg NA NA
1030-1050C65' 67' 68
Abbreviations:
AAS -. Atomic absorption spectrophotometer
APCD - Ammonium pyrrolidine carbodithioate
BOD -- Biochemical oxygen demand
COD -- Chemical oxygen demand
FES -- Flame emission spectrophotometer
GC - Gas chromatography
MIBK - Methy1isobuty1 ketone
MS - Mass spectrometry
NA - Not available
SIE - Selective ion electrode
TDS -. Total dissolved solids
TS - Total solids
TSS - Total suspended solids.
58
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
Table 12, Part 6. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS
OF LIQUID SAMPLES
Notes:
a
Methods currently in use at IGT.
b
Detection limits are estimated as the concentration of the constituent in
the sample solution that would produce a signal twice as large as the
background noise.
c
The range refers to the estimation of the constituent concentration in the
sample solution.
d
Precisions are estimated by applying the specified analytical method to
the sample in the estimated range.
59
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
Table 13. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS OF
GASEOUS SAMPLES
Detection b Precision,
Constitul~nt Method Limita Range %c
Antimony 1. Flamele s s AAS 0.001 ppm NA 5
2. Hydride formation - 0 . 00 1 ppm 3
Heated-quartz-cell AAS
Ar senic 1. APCD-MIBK extraction 0.001 ppm NA 6
Flameles s AAS
2. Hydride formation 0.001 ppm 3
Heated-quartz- cell AAS
Cadmiunl Flameless AAS O. 1 ppb NA 5
Chlorine Amperometrical titration 1 ppm
Fluoride SIE O. 1 ppm NA 5
Germanium Flameless AAS 0 . 0 1 ppm NA 5
Hydrogen 1. Colorimetric method O. I ppm 2-20 ppb 5
Cyanide 2. Pyridine pyrazolone O. 0 1 ppm 4
colorimetric
3. SIE 0 . 0 1 ppm 5
Lead 1. Flameless AAS 0.001 ppm NA 5
2. APCD-MIBK extraction O. 1 ppb NA 6
Flameles s AAS
Mercury Cold-vapor flamele s s 0.01 ppb O. 0 1 ppb 5
AAS
Nitrogen Colorimetric method O. 5 ppm NA 5
(NOz)
Phenolic f: 1. Colorimetric method 2 ppm NA 4
2. GC - hydrogen flame 1 ppm 4
detector
3. GC - MS 1 ppm NA
Selenium Flameles s AAS 0 . 00 1 ppm NA 6
60
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943 .
Table 13, Cant. ANALYTICAL METHODS FOR CHEMICAL ANALYSIS OF
GASEOUS SAMPLES
Detection b Precision,
Constituent Method Limita Range %c
Sulfur Conductivity method O. 1 ppm NA 3
(S02)
Sulfur GC - photometric 0 NA
(Organic) detector
Tellurium Flamele s s AAS 0.001 NA 4
Tin Flameless AAS 0.001 NA 4
Abbreviations:
AAS - Atomic absorption spectrophotometer
APCD - Ammonium pyrrolidine carbodithioate
GC - Gas chromatography
MIBK - Methylisobutyl ketone
MS - Mass spectrometry
NA - Not available
SIE - Selective ion electrode.
Notes:
a Detection limits are estimated for the specified analytical method after
the sample has been put into solution.
b Most ranges of these parameter s are not available.
c Precisions are estimated for each analytical method separately.
61
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
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8/76
8943
SIGNIFICANCE OF RESULTS
Thj.s res earch effort has been directed toward the systematic develop-
ment of an environmental test plan to investigate the fate of constituents of
coal and potentiai pollutants during gasification. The test plan is a logical
and well- conceived approach to the problem of sample collection and analysis
for trace elements in feeds and residues from coal gasification facilities.
Both engineering and scientific contributions have been made in the develop-
ment of the program. Its implementation at the HYGAS pilot plant or a
similar facility will yield important information on the effluent waste streams
and the efficiencies of by-product recovery units. The following dis cus sion
addresses significant areas of the engineering and analytical work that
were performed during the 6 -m:)nth program.
Making an estimate of the environmental impact of a new process
require:> a careful engineering analysis of the process streams. Descrip-
tions of the environment in the reactors and other proces s units,as well as
the posEible pathways the trace constituents may take during gasification,
are included in the HYGAS Process Description. The HYGAS-b~sed process
flow diagram presented in Figure l,is one example of many possible flow
diagram.s and includes pollution-abatement and by-product recovery equip-
ment, designed for producing environmentally acceptable substitute natural
gas. The tables presented in conjunction with the flow diagram completely
characterize the solid, liquid, and gaseous process streams for each of
three coals - Illinois No.6 bituminous coal, Montana subbituminous coal,
and lign..te. Because the design is based on the concept of minimum liquid-
effluent discharge, all process water is recycled to waste-treatment facilit-
ies and :~eturned to the proces s.
A computer program available at IGT to simulate the HYGAS reactor
has allowed us to study many permutations of the operating conditions.
Because the atmosphere to which the trace elements are subjected determines,
to a greHt extent, the thermodynamically stable forms of each element, the
computer program was instrumental in evaluating the effect of process
changes J upsets, etc., on the trace element distribution. We found that
moderat e upsets in temperature and pres sure do not significantly alter the
62
INSTITUTE
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8943
values of the operating regions (Appendixes E and F) and, hence, do not
change the expected trace element distribution. Although, to be certain,
this estimate as well as the effect of larger changes in temperature and
pressure on trace element distribution must be verified experimentally.
The extensive free-energy calculations presented in Appendix E were
executed concurrently with the analysis of the trace-element content of the
coal samples. They represent values of log K for reactions likely to
eq
occur in the different reaction sections across the operating temperature
range, and are based on the most recently determined thermodynamic quan-
tities. The stable forms of the elements studied in each reaction unit are
summarized in Appendix E (Table E..3). General trends are for oxides and
sulfates to be stable in the pretreater, with sulfides and carbonates being
stable in the hydrogasifier. The CO-shift reactor, which is expected to
equilibrate the gas mixture, contains sulfides and some elemental forms.
Heavier metals - generally the more toxic,volatile species - tend to remain
in the neutral, elemental state as gas es or fumes. The operating conditions
in the pilot plant may tend to favor the sulfide forms for these elements,
which would render them more susceptible to complete removal downstream.
As neutral species, their volatilities and low solubilities makes them more
elusive in the gas -cleaning devices.
IGT's trace constituent analysis of coal, feed, and char samples pre-
treatment and hydrogasification stages of bench-scale gasification runs served
as the basis for the trace-element mas s balances found in Tables 4, 6, and
7. Elements showed various levels of loss from pretreater char and from
first-and second-stage gasification as summarized in Table 14.
Some elements are retained by the ash ma terial or are lost at low
« 1 010) levels during gasification of bituminous or lignite coals. These
include barium, cobalt, iron, lithium, magnesium, molybdenum, nickel,
potassium, samarium, silicon, sodium, and titanium.
A few elements show significant losses during gasification of one coal,
but not for the other. For example, when Illinois No.6 bituminous coal is
gasified, calcium, silver, and tin are volatilized by 3410, 6410, and 5010,
63
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Table 14. SUMMARY OF IGT ANALYTICAL RESULTS FOR 38 TRACE AND
MINOR ELEMENTS IN FEED AND RESIDUE SAMPLES OF TWO COALS HYDROGASIFIED .00
IN A BENCH-SCALE UNIT ........
z ~
illinois No.6 Bituminous Montana Li~nite 0'
VI
-! l:-'retreated Hydrogasified Hydrogasified
Feed Residue Residue Loss Feed Residue Loss
Element ppm - %- ppm -%-
-!
c Sb 1. 1 0.78 0.72 35 1.2 0.93 23
-! As 24 21 16 33 18 8.6 52
m Ba 31 30 31 0 1300 1300 0
Be 1.0 0.85 0.76 24 0.98 0.76 22
Bi 1.1 0.94 0.54 51 0.72 0.41 43
0
"TI B 200 190 180 10 85 61 28
Cd 0.89 0.56 0.21 76 0.72 0.33 54
C1' Ca 3500 2800 2300 34 17,000 17,000 0
G') H:»
> C1 2300 1500 590 74 180 95 47
VI Cr 15 15 15 0 14 11 21
Co 3.6 3.6 3.6 0 4.4 4.4 0
Cu 19 19 19 0 8.8 6.2 30
-!
F 61 59 45 26 71 45 37
m
n Ge 4.3 4. 1 3.9 9 2.7 2. 1 22
:r Fe 14.000 13,500 13,000 7 9200 9300 0
z
0 Pb 11 5.8 5.8 47 1.9 1.0 47
r Li 33 33 33 0 5.8 5.8 0
0 Mg 570 600 580 0 5800 5700 2
00
G') ~
Mn 48 44 39 19 8.9 8.5 4 H:»
w
-<
Hg 0.12 0.025 0.0045 96 0.73 0.0075 99
-------
Table 14, Cont. SUMMARY OF IGT ANALYTICAL RESULTS FOR 38 TRACE AND
MINOR ELEMENTS IN FEED AND RESIDUE SAMPLES OF TWO COALS HYDROGASIFIED
IN A BENCH-SCALE UNIT .00
z --
-oJ
VI Illinois No.6 Bituminous Montana Lignite C1'
-I Pretreated Hydrogasified Hydrogasified
Feed Residue Residue Loss Feed Residue Loss
-I Element ppm -oJ,,- ppm -o/c,-
c Mo 7.0 6.9 6.8 3 2. 1 1.9 10
-I 14 7 23 21 9
Ni 15 14
m
N 10,400 10,400 2400 77 9200 1500 84
K 1700 1700 1700 0 340 330 3
0 Sm 0.74 0.74 0.74 0 0.51 0.50 2
-n 13 11 7.5 42 1.7 0.58 66
Se
Si 20,000 20,000 20,000 0 13,000 12,000 8
G"> 0-'" Ag 0.10 0.069 0.036 64 0.24 0.23 4
Iv'"
» Na 1400 1500 1500 0 180 170 6
VI Sr 37 38 37 0 350 230 34
S 38,000 29,400 7800 80 9900 3300 67
-I Te 8. 1 6.3 4.8 41 0.42 0.24 42
m Sn 2.0 1.5 1.0 50 1.9 1.8 5
(') Ti 770 770 750 3 320 340 0
::r
z V 17 15 14 18 67 54 19
0 Yb 0.56 0.55 0.52 7. 1 0.36 0.32 11
,- Zn 49 42 36 27 13 9.5 27
0 25 22 12
Zr 35 33 35 0 00
G"> ~
-< ~
v..>
-------
8/76
8943
respectively.
Roughly one-half of each loss occurs during pretreatment.
Los ses recorded for calciuml silver 1 and tin during gasification of nonpre-
treatec, Montana lignite are 0101 4% 1 and 5'10 1 respectively. In generall
pretreated coals show greater losses of trace elements because another
exit pa':hway is available in the flow scheme. Pretreater charsl tarsI 011s1
and off-gases will contain considerable quantities of trace elements and are
part of the sampling program of the test plan.
Ebments that undergo considerable volatilization in both coals include
arsenicl berylliuml bismuthl cadmium, chlorine, fluorine, lead, mercury,
nitrogenl selenium, sulfur, tellurium, vanadium, and zinc.
Many of thes e
arel of coursel the more toxic elements, toward which
environmental
concern is directed. Even though the losses of each are high, all are ex-
pected to be effectively scrubbed from the product gas strealTI prior to
methan3.tion and recovered in various by-product or waste streams. Tables
4, 6, and 7 are the initial estimates of the fate of trace elements in three
examples of HYGAS-based coal gasification complexes.
The sampling and analytical program presented here is the major
portion of the test plan. It relies heavily upon the accuracy and precision
of the sa.mpling methods, sample preparation, and the analytical techniques
used. The parameters connected with each method or technique should be
evaluated individually for pos sible errors. Any inconsistencies must be
isolated and improved, if possible. The overall precision and accuracy
of the program must be monitored continuously with careful checks.
A comparison between NBS and IGT analytical measurements for four
elements in NBS standard reference materials (SRM) is presented in Table
15. IGT values compare clos ely with NBS values and show good reproduci-
bility. No statistical analysis was atteInpted on these duplicate determina-
tions. While this type of comparison shows acceptable analytical accuracy
and pre :::isionl it does notl however, addres s the difficult problems ass oelated
with obta.ining dependable samples from a coal gasification plant.
66
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8943
Table 15. ANALYSIS OF NBS STANDARD REFERENCE MATERIALS
AT IGT LABORATORIES
Element Sample Form NBS Value IGT Value
pprn --
Arsenic Coal 5.9 (:f:0.6) 5.5, 6.1
Fly ash 61 (:f:6) 59, 57
Lead Coal 30 (:f:9) 27, 28
Fly ash 70 (:f:4) 69, 67
Manganese Coal 40 (:f:3) 39, 38
Fly ash 493 (:f:7) 481, 488
Zinc Coal 37 (:f:4) 39, 38
Fly ash 210 (:f:20) 210, 210
In order to get sufficient data for a statistical treatment, at least 20
samples should be taken at each sampling location during the test program.
The precision of a sampling technique for solids may be' estimated by com-
paring the ash content (corrected for S03) of one sample with the average ash
content of 20 samples. The variation in trace-elements concentration (in
the same coal) from one batch to the next is large enough to make them un-
dependable as tracers.
The representativeness of a liquid sample may be tested by measuring
the sodium contents of each sample or the quantity of particulate matter in
each sample from the same location. There is no true measurement of
accuracy in this sampling technique, because of variations in the composition
of the feedstock plus minor process upsets even at steady-state conditions.
But the problem may be minimized by analysis of large numbers of samples.
The precision of the sample preparation process may be tested by using
a reliable analytical method to measure a certain parameter in the sample
67
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8943
following the sample-preparation steps. Usually one of the major components
in the sample may be measured precisely enough with respect to the reference
parameter to estimate the precision of the sample preparation process. The
accuracy of the sample preparation process may be estimated along with the
analytical methods by using the "known addition" method.
Th,;: precision and accuracy of the analytical methods may be tested by
repetitively analyzing one sample solution by standard addition. To maintain
consist,mcy, this test should also be carried out frequently for NBS and EPA
standard reference materials.
Th4~ analytical methods presented in Tables 11, 12, and 13 of the
"Analytical Methods" section are the most reliable and accurate techniques
availab]e for the analysis of trace and minor constituents in solid, liquid,
and gas ~ous samples. Table 11 outlines methods of analysis for 39 minor
and trace elements that may be found in solid samples. Alternative tech-
niques ~.re offered for flexibility. Their use depends upon the sample
matrix and other pos sible element interferences. Atomic absorption (AAS)
and flame emission spectroscopy (FES) are the major tools for solid sample
analysiE.
ThE analytical techniques presented in Table 12 cover the organic and
inorganj c constituents that may be sequestered in liquid samples. The
various oxygen-demand parameters are included here as are the metals,
total dissolved and suspended solids, mercaptans, nitrogenous compounds,
etc.
Gaseous sample analyses are accomplished largely via flameless AAS
and colorimetric methods following a preconcentration step, as summarized
in Table 13. The analytical techniques presented are for elements that are
likely to appear in any of the gas -sampling streams. The physical properties
of les s volatile species obviate any need for their analysis.
68
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
10.
11.
12.
13.
. 14.
8/76
8943
BIBLIOGRAPHY
1.
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2.
"Air Pollution Codes," Chern. Eng. 80, 11-22 (973) June 18.
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4.
Attari, A., "Fate of Trace Constituents of Coal During Gasification." Report
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5.
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6.
Bethel, F. V.; "The Distribution and Origin of Minor Elements in Coal," Br.
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7.
Bradford, H. R., "Fluorine in Western Coals," Trans. AIME 208, 78 (957)
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8.
Bodle, W. W. and Vyas, K. C., "Clean Fuels From Coal - Introduction to Modern
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9.
Bolton, N. E. et al., "Trace Element Mass Balance Around a Coal-Fired Steam
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INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
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;"1
...?") .
3/76
8943
'I c:
J.. ..J.
Donaldson, W. T.. "Preliminary Chemical Anal ysis of Aqueous \'Va5h:~ Fron~
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H) .
IIE,:oLoav and AnalY6is d Trace Contaminants. i' Pubi. C1C':L-:'
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40.
41.
42.
8/76
8943
29.
Klein, D. H. and Russel, P., "Heavy Metals: Fallout Around a Power Plant, "
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Lee, R. E., Jr. and von Lehmden, D. J., "Trace Metal Pollution in the Environment,"
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- - -
31.
Lisk, D. J., "Recent Developments in the Analysis of Toxic Elements," Science
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32.
Logsden, G. S. and Symons, J. M., "Removal of Trace Inorganics by Drinking
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33.
Lowry, H. H. Chemistry of Coal Utilization, Voll, Suppl. London: John Wiley,
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35.
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36.
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37.
Monkhouse, A. C., "The Minor ConstHuents of Coal, II Coke Gas 12, 363-68
---
(1950) October.
38.
Moore, W. J., Phlsical Chemistry, 3rd Ed. , Englewood Cliffs, N. J . :
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39.
Nabusch, D.F.S., Wallace, J. R. and Evans, C. A., Jr., "Toxic Trace
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"Occupational Safety and Health Standards, Chapter XVII, Part 1910,
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Palache, C., Berman, H. and Frondel, C., The Dana System of Minerolo gy ,
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Perry, J. H., Ed. Chemical Engineers' Handbook, 4th Ed. New York:
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43.
Pollock, E. N., "Trace Impurities in Coal." Paper presented at the American
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INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
51.
52.
53.
54.
55.
56.
57.
58.
8/76
8943
44.
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45.
Rao, C. P. and Gluskoter, H. J., "Occurrence and Distribution of Mineral
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Reid, R. C. and Sherwood, T. K.. The Properties of Gases and Liquids, 2nd Ed.
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Reiter, W. M. and Sobel, R., "Waste Control rv1anagement," Chern. Eng. 80,
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48.
Ring, T. A. and Fox, J. M., "Stack Gas Cleanup Progress," Hydrocarbon
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50.
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72
INSTITUTE
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GAS
TEe H N 0 LOG Y
-------
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
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8943
IITrace Elements: A Growing Appreciation of Their Effects on Man, 11 Science 181,
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Tsaros, C. L., Arora, J. L. , Lee, B. S., Pimentel, L. S. , Olson, D. P. and
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OCR-A.G.A. Joint Project, Institute of Gas Technology, August 1968.
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APPENDIX A. ANALYSES OF SYNTHANE WATER
AND TAR SAMPLES
The liquid effluents from any new commercial gasification facility will
necessarily be treated before discharge to ensure protection of the environ-
ment. The water introduced into a HYGAS plant will be recycled to water
treatment facilities and returned to the proces s; hence, does not pose a
direct pollution problem. Most of the organic material and suspended
solids will be removed from the wastewater, perhaps as by-products;
however, it is of special interest to consider where each potential pollutant
originates in the process.
The analyses that follow in Table A-I involve the overhead condensate
water in Synthane-Process gasification of several different coals. 18 The
Synthane Process operates at roughly l255K (1800 OF) and 40 atmospheres
pressure.
A-I
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8943
Table A-I. WATER AND TAR ANALYSES FROM SYNTHANEa, b
GASIFICA TION I mg /llter (Except pH)
pH
Suspended Solids
Phenol
COD
Thiocyanate
Cyanide
NH
Chroride
Carbon
Hydrogen
Nitrogen
Sulfur
C/H
a
Data from Forney et al.
b
Synthane Water Condensate
Illinois No.6 Wyoming N. Dakota
Coal Subbit. Lignite
8.6
600
2600
15,000
152
0.6
8100
500
8.7
140
6000
43,000
23
0.23
9520
9.2
64
6600
38,000
22
0.1
7200
No flow rates were reported for the streams where sampling was done.
INSTITUTE
VI tima te Analysis of Tar s ,
Synthane Process
Illinois No.6
Coal
Lignite
82.6
6.6
1.1
2.8
12.5
83.8
7.7
1.0
1.1
10.9
A-2
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APPENDIX B. SAMPLE COMPUT ER OUT PUT
Three sets of data from computer runs evaluating the effects of different
operating conditions on hydro gasifier products are presented in Tables B-1
through B-3. The characteristics used in these calculations are those of
Illinois No.6 seam bituminous coal.
Table B-1 shows data for a case at "standard" conditions, i. e., 8275
kN/m2 (1200 psia) and 1300 K (1850 OF) in the steam-oxygen gasifier.
The second set of output (Table B-2) is for "runaway" conditions, i.e.,
high pressure in the reactor (9930 kN/m2, 1440 psia) and high temperature
in the steam-oxygen gasifier (1533K, 2300 OF).
The third set of output (Table B-3) is for a situation of high temperature
(1533K, 2300 OF) and low pres sure (6620 kN /m2, 960 psia).
The composition of the gaseous product exiting from the low-temperature
reactor (second page of each output set) is used as the basis for calculating
the HYGAS operating regions as described in Appendix F. Expressed in
lb-mol/hr, the data may be readily converted to mole fractions for compar-
ison with other raw-gas compositions or for use in equilibrium calculations.
A Datacra£t 6024 computer was us ed for these runs.
program was written at IGT.
The computer
f
~
"
"
I
B-1
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
z
VI
~
~
c
~
m
o
"'T1
C')
:I>
VI
~
m
n
:J:
z
o
r
o
C')
-<
Table B-1, Part 1.
TYPE OF COAL - ILLINOIS NO.6 COAL OATA BASE
------------
CASE 1,
STANDARD OPERATING CONDITIONS
TEMPERATURE, DEGREE F z: bOO. FRACTION OF FEEO CARHON ~HICH IS VOLO\TtLE. LR/LB = .1014
FLO., RATE, LB/HR = 11.Z93U FRACTION OF TOTAL VOLATILE CA~RON WHICH FORMS
GASEOUS HYOROCARPONS OTHtR THAN CH(4)--
CO~"'OSITION, MASS FRACTION. (C(2)H(b) AND Clb)Hlfo,), L8/LB = .11'\41
C = .6~4~ FRACTION OF TOTAL VOLATILE CA~RON ~HICH FORMS
H = .OJ41 CONOt:NSI~LE. OIL ANI' TAR. Ll::I/lH = .20C;~
o '" .1011 H (2) IC RATIO IN CONOENSII::ILE OIL ANU TAR. "'OLE/MOLE: .4S?7
III '" .0121 O/C RATIO IN CONOE~SII::ILE OIL AND TAR. MOLE/""Olf: . 065 7
S : .OJ41:! FRACTION OF CARRON IN GASEOUS HYD~OCARBON~ OT~fR
ASH '" .1164 THAN CH(4),AS C(2)HI6) (REMAINDER AS C(6)H(b)
MOL FjMOU: : .52~1
TOTAL : 1.OOOU
IJj
I
N
~lNtTIC ACTIVITY fACTOR FOR lOW RATE REACTION
~INE.TIC ACTIVITY FACTOR FOR HIGH RAT~ Mt:ACTION
FEED COAL CHARACTERIZATION
----.---------------------
:
1.0000
.9)'10
:
P~OCfSS DESC~IPTION
-------------------
~A~lU RATE TAKIN~ ~LACE IN HTR
~A"'lU RATE ANO OtVOLo\TILIIATION Rt:Acro~ INCluDED
TEMPERATURE OF MJGH TlMPt:PATURf REACTOR. DEG~EE F
~LlCT~OTHtRMAl O~ OXYGEN GASIFIER INCLUO[O
~AL~NCE UN Q~ METHANE
!jALANCE OH HTR
!jAL~NCE ON O~YGE~ GASIFIER
TEMP~~ATU~E UF LOw
TEM~ERATUNl REACTO~. OEGREt F
TE~PERATURE OF ELECT~OTHERMAL GASIFIFR, nEGRfE F
T~MPE~ATURE OF FfED STtAM TO ELf.CTROTHEQ~Al GASIFIEH.
DEGNFE F
TEMPERATURE OF FFEn STlAM TO HIGH TEMPtQATUR[ HEACTO~.
PEGHFF. F
TEMPEHATU~E OF LIGHT OIL SLUN~Y-FEfn. n.E~RtF F
TEMPERATURE OF LI~HT OIL VAPOHIlfQ. nEG~Fl F
SYSTEM P~ESSURF, ATM
RAPID RATE METHANE
:
1?'+A
=
17;:>0.
=
p~.,o.
:
~70.
:
11'00('1.
148
:
:
A(1('1.
:
Al.~6
.1171
:
ex>
-
~
cr--
ex>
-.D
~
L>J
-------
Table B-1, Part 2. CASE 1, STANDARD OPERA T1NG CONDITIONS
00
--
z -..
LOW TEMPER_TURE REACTOR C1'
(I> -----------------------
-I
SOLIDS FLOW RATE,filOLE/I1R FEED CHAR PRODUCT OIL GAS FLO~ RATl,MOLE/HR FHO P~()f1UCT
PHODUCT
-I C 1.0000 .898t. .0209 ..0 .321~ .J374
c 11(2) .2925 .Ob22 .0094 CO(21 .3174 . ]4 ~4
U .1093 0.0000 .0014 Hlel .?4S? .3h44
-I 111(2) .0078 .0050 0.0000 H(210 .3t-~'" .Jq~5
S .0188 .0050 0.0000 CI1141 .2430 .?~~1
m ASH- 2.0129 2.0129 0.0000 C12111(61 0.0000 .00..'1
(':(bIH(bl 0.0000 .001'::>
Tl"'~ERATURE, DEGkl:.E F 600. 1~50. 1248 NI1(31 0.0000 .0057
H(cl!) .0017 .0155
N(21 0.0000 0.0000
0
II H.M~E~ATIJRE, Vf.bPEI: F 1720. 17.4f\
HIG'" T!:.MPERATURF REACTOR
------------------------
C') td
I SOLlllS FLOW RATl,filOLE/HH FEED PRODUCT GAS FLOw ~ATE. ,MUU IHR FFEr) 1 FEE£' 2 PQOnt IC T
> IoN
(I> C .8986 .5454 CU .r3qq 0.0000 .3215
"'(21 .0622 .0377 (':0(;:» .2-42~ 0.0000 .~174
0 0.0000 0.0000 HilI . 3437 0.0000 .2452
"-121 .0050 .0050 ...(cl\) .6190; 0.0000 . ~~f,~t-
~ .0050 .0050 CH(41 .0C;bl 0.0000 .7.430
ASH- 2.0129 2.0129 H(~)S .0(\17 0.0000 .001"
NI.c1 0.0000 0.0000 0.1'000
TE."''''ERA TURE, DEGIoIH F 1250. 1720. TEMPERATURE, I.JFGRFE F IASO. 1000. 177.0.
SULIUS RESrOENCE TIME = 137.4077 '" r NUH:.S.
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Table B-1, Part 3.
CASE 1, STANDARD OPERA TING CONDITIONS
m
o
O)(YGF:N C,ASIFIER
--------.------
SOLIDS FLOW ~ATEtMOLE/HR FEED P~OOUCT GAS FLU'"' RA TI:'...t040LF./HIof FF.ElJ 1 FEEf' 2 PQODUCT
(.; .5454 .Ol67 ro 0.0000 0.0000 .?]49
~121 .0317 .0107 CUI?) o.ooon 0.0000 .?3?A
o 0.0000 0.0000 HIZI 0.0000 o.onoo . ~4 .17
II,jIZI .0050 .OU50 ~q2)O O.ooOn 1.0<;00 .hI4~
S .0050 .0033 CH(4) o.ooOn 0.0000 .<'561
.tJ:j ASH- 2.0129 l.0129 Ole) . 1374 o.onoo o.nonn
I H(2)S D.ooon 0.0(\00 .0017
""" N(2) o.41oon U.OOOO 0.0000
r~"1...t:PA TU~E. DEG~E.E F 1720. 1850. TEt04Pf~_T""'F.. Ot:.C;IoIFF F- :Ho. lion. \p.,o.
~ULl US ~ESIDENCE TIIo4E 0; 16.9_17 MINUTl.S.
'T1
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~
-< U)
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Table B-2, Part 1.
FE~D CU~L CHAkACTE~IZATION
HIGH TEMPERATURE, HIGH PRESSURE OPERA TING CONDITIONS
----~---------------------
TY~l OF CuAL - ILLI~OTS NO.~ COAL UATA ~A~F.
------------
1I:MI-'F.PA I uKf. [11:. ufo< ~ t. F = ~OO. FJ.lACTIUN 0"- F"-ED CAJ./RON 1IIIHICH IS VOLATILE. L8/LR = .1014
FLU.. IJAlt. l I1/HI< = 17.cY.JU FRACTION 0"- TOTAL VOLH ILf. CAJ.I~ON WHICH "-ORIo4S
[,ASElJIJS ... ([)~OC A~ROII.'C:: OTH!:R THAN CH(,+)--
C\J"'~USITIvN. "'AS~ F~ACTIUN. (((2)H(6) /INn C(b)H(f-J)o LA/LA = .lM4]
C = .b'14~ F~ACTION 0"- TOTAL VOL tIT IU. CAIoIHON WHICH F"J./MS
H = .U341 CONUENS I t~LE OIL ANn TAk. U:!/l R = .cOSH
I) = .1 U 11 H(2)/C kATIO IN CONOE.NSIbLE. OIL AND TAR. toAOI r:: /..()!. F = .4":>27
N = .U12' U/C RATllJ IN CUNOENSIfjLI:. OIl. A"'D TAR. ""OLF:/MIII F= .06<;7
S = .U341:1 H~ACTIUN 0"- CA~HUt~ IN r,ASEOUS HYDIoIOCIlRIJONC; OTHR
ASH = . 11 b" THAN CH(4).IIS C(2)H(6) (kf~1I1IN()E~ 115 C(")H(~)
"'0LF/MnLF = .'j?fll
TO 1 AL = 1.uuou
td
I
U1
KINlTIC ACTIVITY FACTOH FUR LOw ..ATt NtACTION
KINUTC ACTIVITy FACTO.. FOJ./ t-
-------
z
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-;
-oj
c
-oj
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Table B-2, Part 2.
HIGH TEMPERATURE, HIGH PRESSURE OPERATING CONDITIONS
LOW TEMPEHATU~E REACTOR
-._-=---~~;=-=~~~~~----
SOL1IJS f-LUIoI ~ATE,"'OLE/Hk FEEU CHA~ PRODUCT OIL GAS fLOW RATE.MOlE/HP FfEf)
PIofQDlJ<;T
C 1.0000 .d98jf, .0209 C(J .399~
"'(2) .2925 .0622 .0094 (012) .Z~'5P
o .1093 0.0000 .O(l}4 ...(~) .7421
111(2) .0078 .0050 u.OOOO l'«c)(J .4t.5'"
S .01~8 .0050 0.0000 (1-1(4) . 1927
ASH- 2.01~9 ~.OI29 0.0000 C(rhi(6) 0.0000
Clb)H(t-) 0.0000
TEM"'£RATURE, OEGtoCt.E f 800, }~90. 1592 Nh(3) 0.0000
~(2)S .0(j41
II/(e) o.onOO
TE.MPERATURE. UEGRf.E F ?l~O.
PRnrJlu::1
. 1t.]5
.36~6
.4145
.443fo
.1>072
.0044
.0015
.OOC;l
.(1179
0,0000
'"5Q2
HIGH TlMPEkATU~E RlACTOW
tJj
I
'"
------------------------
j()LJUS f- LvIII ~A TI: ,"'ULE/HI< FHD P"'vUUCT GAS FLOw RATE ,M()LF /HR FFf[) 1 Fun c ~R()[\Uc:1
\.. .M9tt6 .5~84 (U . 1)~3 o.onoo .]qQJ
1'1(2) .0622 .0414 CO(?) .213C; 0.0000 .;;>~SR
\J O.I)OUO v.OuOO HIt!) .111" 0.0000 .;;>423
1"..( 2) .0050 .UU~O ...(c)O ."'71;;> \J.OOOO .4""50
~ .OO~O .0050 CH(4) .031'~ 0.0000 .lq27
ASH- 2.012Q c.0129 Hle)S .0041 o.onoo .(10'+1
N(C?) 0.0000 0.0000 f).OOOO
Tt."''''t.'''A, TUk£. Ot.Gkt.t. F l';QO. il~U. TE"'PEJ;ATlJRI:.. UFG~Ff:.. f ?100. loon. ?lc.;O.
~ULlIJS joo/t.~IOt::NCI:. 11""E = .1917 M!NuTt.S.
00
-
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'"
00
-.0
~
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-------
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00
-
-.J
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Table B-2, Part 3.
HIGH TEMPERATURE, HIGH PRESSURE OPERA TING CONDITIONS
-I
m
OXYGf"4 uASIFIE.H
---------------
SOL I US fLuW ~ATE..MULE/HH
fEED
PHOOuCT
o
C
~(2)
U
1'1 (c)
~
A~H.
.5984
.0414
0.0000
.OO~O
.OO~O
2.0129
.I.I~OA
.014e
u.OI.IOO
. o II':! 0
.OUOQ
~.Ol;?q
GAS F"L O~ RATE.MOLf/HH F"f:H) 1 fHn 2 ~ROP"CT
co o.ooon 0.0000 . ~n ~ J
(II (2) 0.0001\ 0.0000 . ~ 115
H(d O.ClUOO 11.01100 .~J]"
"(CIa 0.0001\ 1.U<;00 .1>0.77('
CH(4) lI.ooon 0.0000 .11 q<,/
Ii (c) .1'-1'l 0.0000 o.noon
"'(C)~ 0.0000 (J.Hoon . (\ 0'01
f'llc) u.oooo 11.0rooo f1.nnoo
rf"''''F~A TURf. . 1.J1:.r,~FJ: ~ l10. 1100. 7100.
"
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IlM~I:.~ATU~E. UtGM~t F
~ULJUS wt~IDE~tE TIME.
2150. c30u.
.3571 "'ll1tuTt.S.
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Table B-3, Part 1.
HIGH TEMPERATURE, LOW PRESSURE OPERATING CONDITIONS
frfO CUAL CHARACTE~11ATION
------------
IY~~ Of CUAL - ILLINOIS NO.6 COAL DATA ~ASE
--------------~~-~~~s=~~~~
~ .
r~M~~~ATUkE. UEGktt f
FL0~ ~ATE, L~/Hk
COM~USITIUN, MASS
t'~ACTIUI\i,
C
H
U
N
S
AS';
TOTAL
=
tlOu.
1'.L"~3U
:
:
."'JI't!)
.0341
.1011
.0121
.O)"d
. 11 n..
:
:
:
:
:
:
1.1I0UU
tJj
I
00
~INlTIC ACTIVITY fACTOw FOR LOw kArE KEALTru~
KINETIC ACTIVITY fACTOk FUR HIGH kAlt ~EACTIO~
FPACTION Of FfED_CA~eON_~~ItH IS VOLATILE, LB/LH --
fRACTIUN OF TOTAL VOLATILE CA~~nN WHICH Fn~MS
GASEOUS HYO~OCAkAO~S UTHt~ THAN CHI't)--
IC(2)HI6) AND C(6)HI~) I, LH/LR
fPACTION OF TUTAL VOLATILf CAkBON wHICH Fn~MS
CONUENSIhLE OIL ANn TAk, L~/L~ :
H(2)/C kATIU IN CONnENSI~LE OIL AND TAR, MOLE/MOLF:
U/C kATIO IN CONDEMSIBLl nIL AND TA~, MOLf/~OLF:
FRACTION Of CAk~UN IN GASEOUS HYDHOCAk~ONS UTHEk
THAN CH(4) ,AS CI;?)H(") IkFMAltlit)Ek AS CI(,)H«(,»
MOLE/MOLE:
:
1.(\000
.93'10
:
P~OCESS O~SCkIPTION
~APIU kArt TAKl~~ ~LACt IN rlTR
~Al-'lL) RATt ANI) [1t.'wuLATILllATION ktAC10k IhlCLlJ[1ff)
----.--------------
Tl~PEPATU~~ kEACTOw, UE~kEE F
tLECI~OTH~R~AL Uk UAYGlN GASIFIfW INCLUUfu
~AL~NCE UN W~ ~~ ThANE
t!AL~NCE Ut1 Hlk
dAL~NC£ UN O~Yu£~ uASlfIEW
TlMPF~ATU~t UF LOw
T£MPEHATlJo
-------
z
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Table B-3, Part 2.
00
-
-J
0'
HIGH TEMPERATURE, LOW PRESSURE OPERA TING CONDITIONS
LOW TEM~ERATU~~ REACTOR
-----------------------
SOLIOS FLOW ~ATI:'''''OLE/HW fE, f;,Q CHAR "'~lIOl,lCT OIL - .. G~.S FlOw RATE''''OLE/t1~ FF'fO
"'HOOUCT
C. 1.0000 .8~8f, .0209 CO .4597
1'1(2) .29~5 .0022 .0094 CU(2) .?f1R7
U .10~3 u.OUOO .0014 ....Ie) .307Fc
~(2) .007~ .0050 0.0000 H(Z)U .4831
~ .018A .OUC;O , , U.0900 CH(4) .ISO?
ASH- 2.0129 e.U129 u.OOOO C(2)HI~) 0.0001'
C(b)....Cf,) 0.0000
'EM~E~ATUi(E. OEGHE.E F 800. lbOl. 1601 Nj-j(3) 0.0000
HI~)S .004fo
"'(2) 0.000/'1
TEMI-'ERATURE.. OEl.RFE F 2150.
ppn[1llfT
.4l3b
.3"17
.4R99
.4510
. 1 t-4~
. ()04'1
.001':!
.00"17
.0IR~
0.0000
1MIl
l:O
I
-.tr
t1I~t1 TI:MPfWATUHE REACTOR
------------------------
;,uL1U<; FLU,," ~A He .I"ULF.:/HOI F'Ff.D f'I1<,0.
':)()LluS "'E.:; lOt:.NCt:. '1 ME = .12~~ "'INUTI:~.
00
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00
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Table B-3, Part 3.
HIGH TEMPERA TURE, LOW PRESSURE OPERA TING CONDITIONS
-t
m
OXYGfN (,aSJfIE~
---------------
~0LIuS FLUW ~Al~.~ULE/H~
FEELJ
PWO!)UCT
o
l
,., ( t»
I"
I~ (~)
~
A;:)HO
.67bO
.0408
O.OouO
.0050
.0050
c.(llc~
.u~oo
.0163
v.OuOO
.ou<;o
.0003
£.Olc9
GAS now RATE. MOL F IH~ FFfiJ I Fnn 2 PROIiIIC: T
CO 0.(10011 o.onoO ...o~"
CuC?) 0.0 t, 1)(\ u.onO{J .;>I,.,~
H(~) O.II(d}(1 1].0 (1 (I (1 .-,7R4
~(~).) O.u(lon l.v~()O ."374
r"'(4) O.ono" 0.11(10(\ .rl1n(1
() (~) .;;>j51 lJ.UnOO n. (10 II (i
... Cd" o.ooon !I.unoo .po..",
,. (It!) I).oeon o.or.(10 L.onou
Tf M"f~a T' I~F. u!:r,""J:f ~ .~lo. ) 10 n. ?lnn.
-n
G')
>
to
I
t-
o
r!:~~[~Aru~E. DE&~~l F
~(JL jll'; ...t:.~JUt:NCl lIME =
2150. ~30v.
.Jql.. "'JllluTI:S.
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8/76
8943
APPENDIX C.
FLOW RATE DETERMINATION - SCALING FACTORS
The flow rates from Tables 1, 2, and 3 of the text were taken directly
from examples of IGT process designs for commercial-scale coal gasifica-
tion plants bas ed on bituminous 1 subbituminous 1 and lignite coals. The
English units have been converted to the corresponding SI-approved metric
notation. Variations in each process are footnoted at the end of each table.
The design for a lignite-coal-based plant incorporated the use of a magneto-
hydrodynamic (MHD) unit to produce process power. The MHD unit did
effect the quantities of off-site coal required in the process 1 as compared
to coal-fired steam boilers.
Sample feeds 1 intermediate products; and residues from the bE;nch-
scale gasification of Illinois No.6 seam bituminous and Montana lignite
coals were analyzed for trace elements at IGT. No trace analysis has been
completed on a subbituminous coal. The analyses were reported in parts
per million of trace element per unit weight of dry coal fed to the bench-
scale reactor. The flow rates of the three coals fed to a commercial-size
reactor were calculated as -
Lignite
kg/s (dry)
133.29
148.36
177.04
Illinois No.6 Bituminous
Montana Subbituminous
These flow rates do not include steam-plant feed or pretreater losses.
The data from the trace analyses and the flow rates were used to calculate
the corresponding trace -element flow rates in a com.mercial plant.
The calculations for Table 4 (Illinois No.6 coal) were straightforward,
requiring only scaling by a common factor.
The lignite design calls for about 1910 more dry coal fed to the hydro-
gasifier than the subbituminous design, and 1.193239 was used as the factor
to calculate the flow rates for trace elements shown in Table 6 for subbitu-
minous coal. To simplify the preparation of this table it was assumed that
subbituminous coal has approximately the same trace-element composition
C-I
INSTITUTE
o F
GAS
TEe H N 0 lOG Y
-------
8/76
8943
as lignit e coal. (The uncertainty of this assumption was addres s ed earlier
in the report section on Proces s Steps, page 30).
Thu5, based on dry coal feed, the flow rates of each trace element in
Table 7 a.re a factor of 1.193239 greater than the corresponding flow rate
shown in Table 6.
Scaling Factor
To determine the corresponding values of trace-element flow rates
expected from a commercial plant based on data from the HYGAS pilot
plant, the following factors should be used:
HYGAS Capacity
0.787 kg/s raw coal (75 tons/day)
Moistun: Content of Feed Coals, %
Bituminous
6.5
22
Subbituminous
Ligr::.l te
35
Flow Rates of Dry Coal Required, kg/s
Hydrogaslfier
Bituminous
Snbbituminous
Lignite
133.29
148.36
177.04
Conversion Factors Based on Dry Coal
Lignite
Hydrogasifer
181
241. 5
345.9
Bitu:minous
Subbituminous
Note that the lignite factor is 1.9 times the bituminous factor for the
hydrogas ifier feed and 1.4 times the corresponding subbituminous factor.
Energy Flow Rates
The summary table presented in the HYGAS Process Description section
is reproo.uced here as related information. The moisture content, heating
values (HHV), and process mass and energy flow rates for three coals are
C-2
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
shown below with some additional data.
Note that the quantities of coal
energy to the .IProcess" and to the "Offsites" are quite similar for the
bituminous and subbituminous coals, differing from each other by less than
1 and 5 percent, respectively.
Heating
Value, Raw Coal Coal to Coal to Product Process
Dry Basis to Plant Process Offsites SNG Energy Efficiency
Moisture MJ /kg GJ /5 -'70-
Coal Content. % (Btu/lb) (kg/ s)
Lignite a 35 26.2839 4.9902 4.6532 0.3370 3.0528 71.7
(11.300) (292.09) (272.36) (19.72)
Subbitwninous 22 26.2865 5.0750 3.8828b 1.1922b 3.0528 67.2
(II, 30 I) (248.61) (158.68) (48.72)
B itwninous 6.5 29.3142 5.0513c 3.9151 c 1. 1362 c 3.0528 66.2
(12.603) (183.29) (133.29) (38.68)
a A magnetohydrodynamic (MHD) unit provided energy for an electrothermal gasifier in this design.
b Partially dried coal contains 6. 5~;. moisture.
C Dried coal contains <1 ~'~ moisture.
The overall energy efficiency for the subbituminous design is 67.2
percent; that for the bituminous design is 66.2 percent. Because of the us e
of a magnetohydrodynamic unit for electric power generation in the lignite
design, the energy requirements are not comparable to the other two designs.
However, the efficiency of this early lignite-based design was calculated at
71. 7 percent.
C-3
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
APPENDIX D.
DISCUSSION OF PROCESS UNITS AND REACTIONS
To determine the thermodynamically stable form of each trace (or
minor) element in coal in the HYGAS operation, attention was given to the
temperatures of each reaction unit, and to pressure when the reaction was
affected by the pressure. Otherwise, the stable form was calculated on
a thermodynamic basis, and other physical properties indicated the phase
of the material. For volatile elements and compounds, the vapor pressures
were calculated at the temperatures considered.
For purposes of this study, the primary reaction units are the pre-
treater, the high-temperature and steam oxygen gasifiers, and the CO-
shift reactor. The operating conditions and typical gas composition for each
unit are developed in the following paragraphs.
I
Pretreater (for Agglomerating Coals): 700K (800 OF), 115 kN /ml (2 psig)
In the pretreater, the atmosphere to which the coal, including its
mineral matter, is exposed differs throughout the bed and even in different
zones of a particle. Air enters at the bottom of the fluidized bed, while
the gaseous matter devolatilized from the coal contains hydrogen, hydro-
carbons, water, and oxides of carbon and sulfur. Carbon monoxide and
carbon dioxide are also formed during partial combustion of the coal
particles. The pretreater off-gas contains all of these products as well as
unreacted oxygen.
The reaction of oxygen with the particles occurs only in a peripheral
zone of the particles, while partial devolatilization occurs throughout. .
Because of the mixing in the fluidized bed, the residence time, and thus
the extent of the reactions (that of the mineral matter as well as oxidation
and de volatilization of the coal substance), may vary greatly from particle
to particle.
D-l
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
An approximate analysis of pretreater off-gases for Illinois No.6
coal is -
mole% mole1o
CO 3.49 C3Hs 0.46
C:O~ 6.26 N~ 65.09
E'20 20.11 O2 2.37
CH4 0.46 Ar 0.84
C2H6 0.23 S02 0.69
This gas stream also contains the volatilized trace elements listed in
Table 4, under Pretreater Losses.
High-Ternnerature Reactor and Steam-Ox
6995 to 8375 kN m 1000 to 1200 si
The conditions of the HTR and the steam-oxygen gasifier (OG) are the
most ext:reme of the gasification facility. At l300K, many trace elements
are in th,~ vapor phase and available for reaction with other process gases.
The reactors operate as fluidized-bed reactors, and the atmosphere to which
trace and minor elements are exposed is highly reducing. The typical
gas eous .;omponents exiting from the light-oil vaporizer for a bituminous,
subbituminous, and lignite coal are listed below:
Bituminous Subbituminous
Conlponent
Lignite
co
C02
H2
H20
CH4
C2H6
C6H6
NH3
HCN
H2S
Oil
(C3H8)
19.84
14.83
20.66
16.66
13.04
0.13
0.43
0.54
0.03
1.16
12.62
0.01
0.05
100.00
Mole 10
21. 97 11. 49
14.11 14.85
21.18 14.51
17.81 29.39
9.76 16.67
0.79 0.81
0.18 0.13
0.15
0.01 (0.27)
0.19 0.24
13 .83 11.28
0.00186
0.01 0.36
100.00 100.00
cas
N2
INsrlTUTE
o F
D-2
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TEe H N 0 LOG Y
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Wat~r -Gas Shift Reactor: 560K (550 of), 6995 to 8375 kN /m~ (1000 to 1200 psigl
The carbon monoxide-shift (CO-shift) reactor is a fixed-bed reactor
using a cobalt-molybdenum catalyst in which the gaseous compounds reach
equilibrium. The catalyst is tolerant of sulfur compounds and oils in the
feedstock, and it can withstand the high system pres sure and inadvertent
upsets that could introduce water onto the hot catalyst. Typical CO-shift
reactor feed compositions are listed below for the three types of coals:
Component Bituminous Subbituminous Lignite
Mole 10
CO 16.74 19.31
C02 12.51 12.40
H2 17.42 18.62
H20 38.84 38.39
CH4 11. 00 8.58
C2H6 0.36 0.69
C6H6 0.11 0.15
NH3 0.45 0.13
HCN (C3H8) 0.03 0.01
H2S 0.98 0.16
Oil 1. 51 1. 55
COS 0.01
N2 0.04 0.01
100.00 100.00
8.53
9.78
29.81
24.91
24.58
1.20
0.26
. (0.40)
0.53
100.00
Rea cti ons
The reactions studied were thos e considered likely to occur with the
more reactive gaseous components, 1. e., oxygen and carbon dioxide in the
pretreater (but not nitrogen or water), and hydrogen, hydrogen sulfide,
carbon dioxide, carbon monoxide, and water in the hydrogasifier. A com-
puter program was used to calculate the free energy changes (6G) for each
reaction as a function of temperature. Then the equilibrium constants were
calculated from the equation -
/).G = -RT tn K
eq
D-3
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8943
where t..G is the free energy change (cal/g-mol), R is the gas constant
(cal/g-:mol-K), and T is the absolute temperature (K). The equilibrium
constant (K ) is des cribed in Appendix F in connection with the determina-
eq
tion of operating regions. The results of all these calculations are tabulated
in Table E-2, Appendix E. Plots of log K versus temperature for several
eq
kinds of reactions are included later in this report. (See Figures E-3
through. E -21, Appendix E. )
The earlier. equilibrium calculations included oxidation reactions for
carbides and nitrides; however, a literature investigation of naturally occur-
ring ni.i;rides and carbides failed to reveal any (except carbides in some
iron mdeor!tes). Later calculations concentrated on the typical modes
of trace and minor elements in coal as reported in the literature. (See
Bibliog:raphy entries 6, 7, 20, 34, 45, and 50.) Table 5 (refer to main
text) summarizes the literature information as to the pos sible modes of
occurrf~nce of trace elements in coals. Thus, for example, cadmium
exists in coals as cadmium sulfide (CdS), and calculations were made with
CdS as a. reactant.
Thl~ reactions for the three reaction areas are listed below:
PJ'etreater MS + 3/2 02 +! *
MS03
MS + 202 +! MS04
MS + 3/2 02 +! MO + S02
MO + C02 +! MC03
MS04 +! M02 + S02
H~~R, OG, MS + H2 +! M(s,g) + H2S
CO-Shift
MO + H2 +! M(s,g) + H20
MS + H20 +! MO + H2S
MS + C02 + H20 ~ MC03 + H2S
MS04 + H2 ~ MS03 + H20
MS03 + 3H2 ~ MS + 3H20
MO + C02 ~ MC03
MO + 2HCl ~ MC12 + H20
MS + 2HCl +! MC12 + H2S
MO + 2HF ~ MF 2 + H20
~-
. M refers to the elements in this stud y
D-4
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Some other reactions were investigated thermodynamically where data were
available. These involved nitride or carbide hydrolysis, hydrogenation or
oxidation, and hydride formation:
MS + 2H2 t MH2 + H2S
MO + 2H 2 +! MH2 + H20
M2C3 + 2H2S + 4H2 +! 2MS + 3CH4
MC2 + H2S + 3H2 +! MS + 2CH4
M2C + C02 + 2COS +! 2MS + 4CO
M2C + 2H2S +! 2MS + CH4
M3N2 + 3H20 +! 3MO + 2NH3
M3N2 + 6H2 +! 3MH2 + 2NH3
Calculations were done to compare the relative stabilities of chloride com-
pounds with first- and second-period oxides and with BeCll or MgCll, such
as -
M20 + BeC12
M20 + MgC12
+!
2MCI + BeO (See Figure E-16.)
2MCI + MgO (See Figure E-17.)
+!
Finally, the formation of BeHz(g) and the reactions of KO(g) were investi-
gated:
BeS + 2H2 +! BeH2(g) + H2S
BeO + 2H2 +! BeH2(g) + H20
Be2C + 4H2 +! 2BeH2 (g) + CH4
2KO(g) + H2S +! K2S (5) + H20 + 1/202
2KO(g) + H2S ~ K2S (5) + H202
KO(g) + 3/2H2 ~ KH(g) + H20
D-5
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As this work progressed, gaps in the data interfered with the complete
and detailed analysis that was our aim. It is apparent that even though
interest is growing in trace-element research, considerable work is re-
quired jn the area of thermodynamics.
Whare data were not available, not applicable to a certain temperature
range, or of uncertain or questionable validity, the similarity in physical
and theJ'modynamic properties of compounds formed from elements in the
same period of the Periodic Table was used as a basis on which to interpo-
late potr~ntial results. Some generalizations can be made concerning the
trace elements on this basis. For example, the first period elements tend
to favor carbonate formation in the hydrogasifier. The stable forms of the
elements in the Periodic Table range from carbonates on the left, to oxides,
to sulfic:es, and to non-metallic hydrides on the right. Many heavy metals
tend to :~emain in the elemental form.
Of course, some elements are ex-
ceptionE to this generalization. As far as the data indicate, sodium chloride,
zircon, boron fluoride, and tin (II) chloride are stable in the hydrogasifier.
FOI all thermodynamic calculations in the three :main reaction units,
the opelating region was determined and compared with the equilibrium
constant. If the value of the operating region was less than the calculated
value of K , the reaction proceeded as written. If the value was greater,
eq
the reverse reaction was assumed to occur. This assumption follows directly
from thermodynamic considerations and allows for sufficient time to equi-
librate. For example, in the case of the reaction
PbS(s) + HzO(g) i! PbO(s) + HzS(g)
occurring in the steam-oxygen gasifier at l300K, the value of log K is
eq
--4.417. The value of the operating region (determined from Table E -1,
Appendi;~ E, for the reaction type - MS + H20 i! MO + H2S) is -1. 16. The
value of log K is less than the value of the operating region, therefore,
eq ,
the reverse reaction is favored. (See Appendix E for additional examples.)
This study does not take into account the kinetics and reaction rates of
the individual components, the complex problems associated with hetero-
genous leactions, or the effects of diffusion. Thus, it may be possible for
an oxide to exist in the gasifier when thermodynamically it should be a sulfide.
D-6
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8943
Similarly, a sulfide may not be completely oxidized in the pretreater, but
may exit as a sulfite or sulfide. Gaseous reactions that are expected to
occur in the CO-shift reactor will be catalyzed readily.
When predicting the fate of trace elements, the problems are multiple,
as the actual form of an element may be quite different from the calculated
form.
With continued research and the analysis of HYGAS process and by-
product streams, these questions will be more readily answered, contri-
buting to the understanding of possible trace-element emissions and to the
design of more environmentally sound process.
D-7
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
APPENDIX E. Presentation and Discussion of
Thermodynamic Calculations: Tables and Graphs
The following tables and graphs are the result of computer and other
calculations made to determine the equilibrium constants (K ) for many of
eq
the reactions more likely to occur in a coal-gasification plant.
The tables list the elements, each followed by the relevant reactions
(oxidation) of the pretreater, and the reduction reactions (hydrolysis,
hydrogenation, carbonation, or exchange) of the hydrogasifier and CO-
shift reactor. Miscellaneous reactions are pres ented when the physical
properties of an element warrant - such as low bubble point, high vapor
pressure, or toxicity. Across from each reaction, the log of the equili-
brium constants (log K ) is listed for temperatures encountered in the
eq
major reaction units: 1300, 700, and 600K. Values for other temperatures
are presented when the available data did not extend to 1300K. Occasionally,
data were estimated through extrapolation.
Equilibrium curves for pretreater, hydrogasifier, and CO-shift reactions
are presented in Figures E-l to E-l9.
is temperature in degrees Kelvin (K).
The ordinate is log K ,. the abscissa
eq .
The first- and second-period elements -
lithium, sodium, potassium, beryllium, magnesium, calcium, strontium,
and barium - are analyzed in detail in these graphs. The periodic nature
of their thermodynamic properties is evident and can be used to extend
data to other, less documented elements with confidence.
Figures E-l, E-2, and E-3 indicate that the oxidized form of these
elements is favored thermodynamically in the pretreater. Figure E-4 shows
that only beryllium chloride and magnesium chloride would tend to oxidize
in the pretreater. The other reactions are possible, though unlikely, pro-
vided that fluorine and chlorine gas partial pressures are small enough to
draw the equilibrium to the right.
Carbonate-forming reactions are presented in Figures E-5 through
E-8. For the first period oxides or sulfides, carbonates are the stable
form. The heavier second-period oxides and sulfides will form carbonates
preferentially in the CO-shift reactor (but not beryllium oxide), while the
operating conditions in the hydrogasifier favor carbonate formation from
E-l
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
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8943
barium oxide, strontium oxide, beryllium sulfide, magnesium sulfide,
strontium sulfide, and barium sulfide. In cases where the operating region
overlapt> the plotted equilibrium curve, such as in Figures E-7 and E-8,
the direction of the reaction may be evaluated by Le Chatelier's Principle.
This principle states that:
"Any change in one of the variables that determines the state of a
system in equilibrium causes a shift in the position of equilibrium
in a. direction which tends to counteract the change in the variable
under consideration. II
E-Z
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
o BeS+ 31202~ BeS03 OJ
"-
50 t:. --.)
z MgS+3/202 == MgS03 0"-
V> 0 CaS + 3/202:= CaS03
-I \J SrS + 31202 ~ SrS03
-I 40 0 BaS + 3/202:= BaS03
c 0 VALUES OF LOG
-I
m
- 30
"5
C'
CD
0 ~
"T1 ~
0
.....J
20
M
G) I'
\..V
»
V>
10
-I
::I:
300
m
o
o
400
500
600
700
800
K
900
1000
1100
1200
1300
z
o
A-124-2209
r
Figure E-l.
OXIDATION REACTIONS OF SECOND-PERIOD SULFIDES TO SULFITES
Values of Log fl /(P 0 )3/2-1 at 600 ~ = A- (CO-Shift)
L 2 -1 700 K = 1.02 (pretreater)
1300 K = l' (HYGAS)
~ The partial pres sure of oxygen in these units is vanishingly
small. The value of log approaches 00.
OJ
~
*'"
\..V
o
G)
-<
-------
o BeS03 + 1120Z= BeS04
50 6 MgS03 + 1/202=MgS04 O'a
-
o CaS03 + 1/202:::CaS04 -.J
z 0'
CI> 'V SrS03 + 11202:::SrS04
A. BaS03 + i/202=Sa504
-I v
40 @ VALUES OF LOG
-I
c
-I
m
"5 30
go
G)
~
(!)
0 0
-I
."
20
C"> M
I
~
»
CI> 10
m
o
-I
()
300
400
500
600
700
800
K
900
1000
1100
1200
1300
:I:
z
o
A-1I4-ZZIO
r
Figure E-2.
OXIDATION REACTIONS OF SECOND-PERIOD SULFITES TO SULFATES
Values of Log ~.I (P 0 )1/2J at 600 K = .~. (CO-Shift)
2 700 K = 0.34 (pretreater)
1300 K = ." (HYGAS)
.'f. The partial pressure of oxygen in these units is vanishingly
small. The value of log approache s oo.
00
~
f!:>.
VJ
o
C">
-<
-------
z
V>
-t
-t
C
-t
m
o
"
M
G"> I
U1
}>
V>
-t
m
n
:t:
z
o
r
o
G">
-<
140
120
100
.S
tr
-:2 80
<.!>
o
.-J
60
40
20
300
Figure E-3.
00
.......
-.J
0'
o Be3N2 + 7/202= 3BeO+ 2N02
/:). M93N2 + 7/2 O2 = 3MgO+ 2N02
o Co3N2+7/2Qz= 3CoO+2NOz
"iJ Sr3 N2 + 7/2 O2 = 3SrO + 2N02
<> B03N2 +7/202= 3800+ 2N02
Mg2C3+ 402 = 2MgO + 3C02
. COC2+ 15/202 = CoO+ 2C02
400
500
600
700
800
900
1000
1100
1200
1300
K
A-IZ4-2217
OXIDA TION REACTIONS OF SECOND-PERIOD NITRIDES AND CARBIDES TO OXIDES
Assuming 10 ppm NOz in the NOz-Forming Reactions, at 700 K, the
Values of Log [(PNOz)Z /(P 0) 7/ZJ = - 7.63 (pretreater)
Log [(P CO)3 /(p 0)4] = - 0.90 (pretreater)
o Log [ (p caz)Z / (P OZ)5/ZJ = - o. 71 (pretreater)
00
-.D
.j:>.
lJ,)
-------
z
~:l~
v
CJ>
-!
-I
o
8/. i Clz REACTIONS
< Fz REACTIONS
c
-I
m
-10
o
'5
C'
.,
::.:: -20
<.!)
o
..J
.I::r-----b--
.1:----- --r-
I::r---- ---- v
../:::r---- ----V --_4--
..J:y---- ---_JJ- ---::Z=-::-::.:8:::::
~~ ~-~ -~-~:-=~~--
,..... ,.»--.s3-- ---:1=--
/~ .-- .---Ar----
," J;;-""'" ...s::J'- ,,""-,.-
./ ,'..,...- ....- --
N """-'-
,,- ,'" /1"""- -- ........"
,,/" ""V /"'At-/",,-- 0 BeClz + I/Z02 = BeO + CI2
""" ",/" """ """ "" f:j BeF2 + 1/202= BeO + F2
)f/ ;/ ,;:r~""":",,,8' 0 MgCI2 + 1/202:: MgO + CI2
/ ",'J/ """/",,.'./""" 'V MgF2+1/202;::MgO+F2
/ / """ """:,.f <> CoCI~ + 1/2 O~ ~ CoO + CI2
, "" "" "" """ ' ,-
/ /""?J" /"",/ SrCI2 + 1/202= SrO+CI2
/ / ///!" -CI2REACTIONS eSrF2+1/202=SrO+Fz
/ // / I"// ----F2REACTIONS . BoCI2+1/202= BoO+CI2
/ / /// . BoF2+1/202=BaO+F2
400 500 600 700 800 900 1000 1100 1200
K
."
-30
M
G) I -40
0"-
>
CJ>
-50
-I
-60
300
1300
m
n
::r
A-124-2219
z
o
Figure E-4.
OXIDATION REACTIONS OF SECOND-:PERIOD CHLORIDES AND FLUORIDES TO OXIDES
..
Assuming Clz = 10 ppm and Fz = 1
Values of Log [(P Clz)J (P 0)1/2J =
Log [(PFz)J(POz)1/2] =
ppm in the Pretreater, at 700 K, the
- 4.66
o
G)
-<
-5.66
~
-..
-J
0'
00
...0
~
W
-------
z
6
V>
-I
-I
o K20 + C02 :=:K2C03
~ N020+C02::=No2C03
o Li20+C02~Li2C03
o VALUES OF LOG
c:
-I
40
m
o
"11
"M
C'> I
-J
»
V>
~
C'"
Q)
~
<9 30
o
.-J
20
10
-1
m 0
() 300
:I:
Z
0
r
0
C'>
-<
K
A-124-2214
Figure E-5.
CARBONATE-FORMING REACTIONS OF FIRST-PERIOD OXIDES
Values of Log (liP caz) at 600 K = -1. 36 (CO-Shift)
1300 K = -1. 17 (HYGAS)
co
-
-J
0'
co
-.0
~
w'
-------
z
V>
-I
-I
c
-I
m
o
1i 7
tT
GO
::,c:: 6
(.!)
o 5
-.J
11
C>
>
/:%:I
I
Q:)
tI>
-I
m
n
:r:
z
o
r-
o
C>
14
13
12
II
10
9
8
4
3
2
o
-I
-2
-3
-4
300
o K2S + C02 + H20 := H2S +K2C03
6. No2S + CO2 + H20;: H2S + No2C03
o Li2S + C02 + H20;: H2S + Li2C03
00
-....
--.1
n--
r\ \11\.1 IIC'C: ,",co I "r..
""-J .."._--- -. ---
400
500
600
700
800
K
900
1000
1100
1200
1300
S-124-2;>06
Figure E-6. CARBONATE-FORMING REACTIONS OF FIRST -PERIOD SULFIDES
Values of Log '-(PH S)/(PH O)(PCO )J at 600 K = -2. 71 (CO-Shift)
- 2 2 2
1300 K = -2. 33 (HYGAS)
-<
ex>
...0
~
v.>
-------
z 20
V>
-i
-i
C
-i
m
o
"T1
tr1
C'J I
-.D
>
V>
:J
CT
G>
~
~
o
-I
~
m
()
:I:
z
o
I
o
ex>
.......
-.J
0"
o BeO+ C~ ~BeC03
t::. MgO+ C02 ~ MgC03
o CoO+ C02~ Co C03
'V Sr 0+ C02:;!::Sr C03
o BoO+ C02:;!::Bo C03
@ VALUES OF LOG
10 -
CO-SHIFT
-10
300
400
500
600
700
800
K
1000
1100
900
8-124-2211
Figure E-7.
o
C'J
-<
CARBONATE-FORMING REACTIONS OF SECOND-PERIOD OXIDES
Values of Log (1 Ip C02) at 600 K = -1. 36 (CO-Shift)
1300:< = -1. 17 (HYGAS)
ex>
-.D
~
v.>
-------
z
24'
22 ex>
-
--.J
20 0"-
18
o BeS + H20 + C02:::BeC03 + H2S
~ MgS + H20 . C02~MgC03 + H2S
o CaS. H~+C02~CaC03.H2S
"iJ SrS. H20 + C02~SrC03 +H2S
o BaS + H20. C02~BaC03 +H2S
o VALUES OF LOG
II>
-i
-i
c
-i
m
...-
12
-- 10
::3
0-
CD 8
:x:
(!)
0 6
..J
4
2
0
-2
-4
-6
-8
300 400
.COSHIFT
o
"
C')
>
M
I
o
II>
-i
m
()
z
500
600
800
K
900
1000
1100
1200
1300
::I:
o
B -124- 2218
r
-<
Figure E-8. CARBONATE-FORMING REACTIONS OF SECOND-PERIOD SULFIDES
Values of Log [ (PHzS)j (PHzoHP CO) J at 600 K = -2. 71 (CO-Shift)'
1300 K = -2. 33 (HYGAS)
ex>
-..D
~
u.>
o
C')
-------
z
II>
-I
-I
c
-I
m
o
."
tr:1
G') I
.......
> .......
II>
-I
m
n
:J:
z
o
r
o
G')
-<
4
3
2
o
CO-SHIFT
-I
-2
::J
g -3
~
C) -4
o
..J
o Li2S04 + H2 ... Li2S03 + H20
[j, Li2S03 + 3H2 ... Ll2S + 3H20
o Na2S04 + H2 ... Na2S03 + H20
'il Na2S03 + 3H2 ~ Na~ + 3H20
o K2S04 + H2 .~ K2S03 + H20
-------
z
CI>
-j
-j
c::
-j
m
o
"T1
C'> M
I
'-'
> N
en
-j
IT!
()
:r
z
o
r
o
C)
-<
4
3
2
-5
:; I
~
Sr S04 + H2 == SrS03 + H20
. Sr S03 + H2 = SrS + 3 H20
A 8aS04 + H2 == 8aS03 + HzO
. 8aS03 + H2= 8aS + 3HzO
-2
-3
o VALUES OF LOG
-4
-5
-6
300
1100
1200
1300
A-IZ4-2213
Figure E-10.
REDUCTION REACTIONS OF SECOND-PERIOD SULFATES TO SULFITES TO SULFIDES
Values of Log [(PHzO)/(PHz)] at 600 K = -0. 07 (CO-Shift)
1300 K = -0. 09 (HYGAS)
Log r(PH )3/(PH )3lat 600 K = -0.22 (CO-Shift)
L zO z -'
1300 K = -0. 28 (HYGAS)
00
.......
-..J
0'-
CP
~
J4:>.
1.,.0.)
-------
ex:
-
Z --.J
'"
U>
-I
40
-I 0 K20+ H2S= K2S + H20
c l:J. Li20 + H2S == Li2S + H20
-I
30 0 Na20 +H2S= Na2S+ H20
m
0 VALUES OF LOG
::I
C'
at
0 ~
t') 20
"T1 0
....J
M
,, ~ 10
.....
» w
U>
o
300
400
800
900
1000
1100
-I
m
K
n
:I:
A-124-2207
z
o
r
Figure E-11. SULFIDE FORMATION FROM FIRST-PERIOD OXIDES
Values of Log [(PHzO)/(PHzS)] at 600 K = 1. 35 (CO-Shift)
1300 K = 1. 16 (HYGAS)
o
"
-<
00
-.D
~
W
-------
o SrO + H2S;:: H zO + SrS 00
........
20 6 BeO+H2S;= HzO+BeS --J
z 0'
(I> 0 MgO+HzS;= H20+MgS
-i V CaO+H2S;= H20+CaS
0 BaO+H2S= HzO+BaS
-I 0 VALUES OF LOG
10
c
-I
m
CO-SHIFT
.5 0
C"
CI)
0 ~
" (!)
0
.....J
-10
l'1
(;) I
......
:t> ~
(II
-20
-I
m
n
::t
z
o
r
o
(;)
-<
300
700
1300
-30
400
500
600
800
K
900
1000
1100
1200
A-124-2212
Figure E-12. SULFIDE FORMATION FROM SECOND-PERIOD OXIDES
Values of Log [(PH O)/(PH s)l at 600 K = 1. 35 (CO-Shift)
z z -
1300 K = 1. 16 (HYGAS)
00
-..D
~
W
-------
8/76
8943
-20
30
20
10
CO-SHIFT
:3 0
C"
Q)
~
<.!)
0
...J
-10
o VALUES OF LOG
o BeCI2+ H2S~BeS + 2HCI
fj, MgCI2+H2S~MgS+2HCI
o CoCI2+H2 S~Co S + 2 HCI
"iJ BeF2 +H2S~BeS +2HF
o MgF2+H2S:O<=MgS+2HF
M92C3+2H2S=2MgS+3CH4
. CoC2 +H2S+3H2-:::CoS + 2CH4
A Be2C+C~+2COS:O<=2BeS+4CO
. Be2C + 2H2S~2BeS +CH4
-30
-40
300
400
500
600
700
800
K
900
1000
1100
1200
1300
9-124- 2294
Figure E-13. SULFIDE FORMATION FROM SECOND-PERIOD
CHLORIDES, FLUORIDES, AND CARBIDES
Assuming HC1 :: 500 ppm and HF :: 50 ppm, the
Values of Log [(PHC1)2/(PH2S)] at 600 K:: -2.63 (CO-Shift)
1300 K :: -2.67 (HYGAS)
Log [(PHF)2/(PH2S)] at 600 K:: -4.63 (CO-Shift)
1300 K :: -4. 67 (HYGAS)
For Eq.£ Log [(PCO)4/(PCOS)2(PC02)J at 1300 K:: 8.02 (HYOAS)
For Eq.8 Log [(PCH)/(PHzS)2Jat 1300 K:: 0.99 (HYGAS)
For Eq.. Log [(PCH4)Z/(PH)3(PHzS)] at 1300 K:: -1. 78 (HYGAS)
E-15
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
00
60 I .......
-J
Z 0'
CI> 0 u?o + BeCI?~BeO +2LiCI
~ ~ N020+ BeCI;~BeO+2NoCI
50 0 K20 + BeCI2~BeO+2KCI
-I \l MgO+ BeCI2~BeO+MgCI2
c: 0 CoO+ BeCI2~BeO +CoCI2
-I <] SrO + BeCI2~BeO + SrCI2
m 40 I> BoO+ BeCI2~BeO +BoCI2
~
0 C'"
Q)
"'TI ~ 30
(!)
trJ g
C'> I
...... 20
:t> 0'
VI
10
-I
m
n
:x:
o
300
400
500
600
700
800
900
1000
1100
1200
1300
z
o
K
,...
A-124-2222
o
C'>
Figure E -14.
FORMATION OF BeO FROM BeClz AND FIRST- AND SECOND-PERIOD OXIDES
00
-..D
~
~
-<
Note: Operating Regions (Log Values) are not calculated for solid-phase reactions such
as these.
-------
00
-
-J
Z '"
VI
-t 50
-t 0 Li20+ MgCI2~MgO + 2UCI
c ~ N~O+ MgCI2~MOO + 2NaCI
-t 40 0 K20 + MgCI2~MgO + 2KCL
m 'V CoO + MgCI2-MgO+ CaCI2
0 SrO + MgCI2-MgO+ SrCI2
<] BoO + MgCI2-MgO + BaCI2
:J
0 t:T30
Q)
" ~
(!)
0
M --I
. 20
C> I
......
» -J
VI
10
-t
m
::I:
o
300
500
700
"K
900
1100
1300
A-124-2215
(')
z
o
r
o
C>
Figure E-l5.
FORMATION OF MgO FROM MgClz AND FIRST- AND SECOND-PERIOD OXIDES
00
';i?
VJ
-<
Note: Operating Regions (Log Values) are not calculated for solid-phase reactions such
as these.
-------
(;)
»
M
I
......
00
140
130
120
iiG
100
90
80
70
"5
C'"
v 60
~
~
0 50
-..J
40
30
20
10
0
-10
-20
-30
-40
-50
300 400 500
o Be3N2 + 3H20 ~ 3BeO + 2NH3
6 M93N2 + 3H20 ~ 3MgO + 2NH3
o Ca3N2 + 3H20 ~ 3CaO + 2NH3
Sr3 N2 + 3H20 ~ 3Sr 0 + 2NH3
0__'"1.... .1.. "'2~-" - ~.C),...~ .". ~."..'
--~....c:: . .....,(:..... - "''-'w- I ~1~f'3
'\J Be3N2 + 6H2 ~ 3BeH2 + 2NH3
o VALUES OF LOG
co
-
--:J
0'
z
C/)
-i
-i
C
-i
m
o
"11
VI
-i
600
700
800
900
1000
CO-SHIFT
m
1100
1200
1300
()
:I
i<
8-124-2216
z
Figure E-16. HYDROLYSIS OF SECOND-PERIOD NITRIDES TO OXIDES AND NH3-
HYDROGENA TION OF Be3Nz TO Be Hz
For Eq.V , Assume BeH2 = 1 ppm, the
Values of Log [(PNH3)2(PBeHz)3 /(PH)6 ] at 1300 K = -12.43 (HYGAS)
Log [(PNH3)z/(PHzO)3J at 600 K = -4.83 (CO-Shift)
1300 K = -4.20 (HYGAS)
co
...0
~
v.>
o
r
o
(;)
-<
-------
z
VI
-i
-i
c
-i
m
":;
0'
GI
0 ~ 30
~
-n 0
~
M
C') I 20
.......
> -.D
VI
10
-i
m
n
:r
z
o
r
o
C')
-<
60
ex:>
-
-...J
0'
50
o 2 KO(g)+ H2S(g) = K 2S(S) + H20(g)+ 1/2 02(g)
t:.. 2KO(g)+ H2S(g) ~ K2S(S)+ H202(g)
o KO(g)+3/2 H2(g)= KH(g)+ H20 (g)
o VALUES OF LOG
40
o
300
400
500
600
700
800
900
1000
1100
1200
1300
K
A-124- 22 08
Figure E-l7. MISCELLANEOUS REACTIONS INVOLVING KO (g)
Assuming KO = 1 ppm and Oz = O. 01 ppb, the
Value of Log [(P OZ)l /Z(PHzO)/(PHzS)(PKO)2 J at 1300 K = 4.66
00
-.D
~
W
(HYGAS)
-------
o
-I
-10
CO-SHIFT
I:::~
ex>
-
---.J
0"
z
(f'I
FOR Eq. 0
-i
C
-20
-i
m
o
::3
tT
Q)
~ -30
<..!)
3
'TI
-40
M
Q I
N
» 0 -50
(f'I
o BeS+2H2:;!:BeH2(g) +~S
b, BeO+2H2:;!:BeH2(g) + H20
o B~C+4H2~2BeH2(g)+CH4
o VALUES OF LOG
-60
300
400
500
600
700
800
K
900
1000
1100
1200
1300
-i
A-124-2220
m
n
:I:
Figure E-18. HYDROGENATION OF BERYLLIUM COMPOUNDS FORMING BeH2 (g)
Assuming BeHz = 1 ppm, the
Values of Log !-(PH S)(PB H )/(PH )21 at 600 K = -6.88 (CO-Shift)
L 2 e2 2.~
1300 K = -6.57 (HYGAS) for Eq.O
Log r(PH O)(PB H )/(PH )21 at 600 K = -5.53 (CO-Shift)
L Z e 2 2....!
1300 K = -5.41 (HYGAS) for Eq.~
Log [(PCH)(PBeHz)/(PH2)4] at 600 K = -12. 73 (CO-Shlft)
1300 K = -12. 15 (HYGAS) for Eq.O
ex>
--0
~
vv
z
o
r
o
Q
-<
-------
-I
m
n
:I:
z
o
r
o
c;')
-<
o Sb2S3 + 3C02 + 3H20 -- Sb2(C~3 + 3H2S
/:;). Sb2S3 + 9/2 02 ~ ~ Sb2(S03)3
o Sb2S3 + 6 02 . ~ Sb2(S04)3
\l AS2 S3 + 3H20 .. AS203(g) + 3H2S
o Sb2(S04)3 + 12H2 -- Sb2S3 + 12H20
o VALUES OF LOG
Figure E-19.
FOR Eq. 0
FOR E FORf~ /:;).
q.O .:':;:::'}:"",:::::,,:
FOR Eq. 'V
CO-SHIFT
HYGAS
500
600
700
800
70
z
VI 60
-I
50
-I
c: 40
-I
m 30
.-
::::J 20
0-
Q)
0 ~
"TI (!) 10
0
.-J 0
M
c;') I
N
...... -10
»
VI
-20
-30
-40
-50
300 400
900
1100
1000
1200
1300
K
A-124-2223
MISCELLANEOUS REACTIONS OF ANTIMONY AND ARSENIC COMPOUNDS
ex-
--
-.]
0'
00
-D
~
t.V
-------
8/76
8943
The elevated pressures found in the hydrogasifier favor carbonate
. formation in these reactions. This follows from a consideration of the
effect of pressure on reaction equilibrium for several situations which may
be encountered:
1.
BeS + H20 + CO2 ~ BeC03 + HzS (Figure E-8)
BeO + H2S ~ BeS + H20 (Figure E-12)
2.
3.
HzO +! Hz + 1/2 Oz
4.
MgC12 + LizO ;! MgO + 2LiCl (Figure E-15)
In case I, two moles of gas (HzO, COl) will react to form one mole of
gas (HzS). Increasing the partial pressure of either H20 or CO2 (or decreas-
ing PH <;;), will push the reaction to the right. Decreasing the partial pres s-
2'-"
ure of H~O or CO2 (or increasing Hl5 or introducing inert gas), will pull the
reaction to the left.
In ca.se 2, one mole of HzO will react to form one mole of HzS. Varia-
tions in pres sure will not affect the equilibrium conversion of this reaction.
In case 3, one mole of gas decomposes to form 1.5 moles of product
gas. Increasing the partial pressure of H2 or 02, will force the equilibrium
to the left.
In case 4, solid phase reactions are not affected by changes in system
pressurE:. (See comments on Figures E-14 and E-15).
The effect of pressure can be similarly judged for the other reactions
pos ed in this study.
Figures E-9 and E-IO show the steps of reduction for the first- and
second-period sulfates. The reduced forms of these elements are stable
with respect to the oxidized forms in the HYGAS reactor. In Figure E-9,
the redu<:tion of sulfate to sulfite is not fa vored, but the overall reaction of
sulfate to sulfide is favored in the hydrogasifier.
Figures E-11 and E-l2 attempt to tie the oxides and sulfides together
in the hydrogen sulfide/water exchange reactions. In general, the sulfide
form is preferred, except for beryllium and magnesium oxides.
E-22
"I N S TIT UTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
In Figure E-13, various chloride, and some miscellaneous reactions
are presented. Here it is assumed for calculational purposes, that 500 ppm
of chlorine (as HCl) and 50 ppm of fluorine (as HF) exist in the HYGAS and
CO-shift reactors at steady state. The chlorine levels for some lignite
feeds may be this high in the raw gas from the hydrogasifier but much lower
in the CO-shift reactor, depending upon removal efficiency during water
quenching. These reactions go to products as indicated.
Figures E-14 and E-15 show that beryllium and magnesium oxides are
thermodynamically favored in these solid-phase exchange reactions. This
is evidenced by the high positive values for the log of the equilibrium constant
(log K ) over the given temperature range.
eq
The hydrolysis of nitride compounds is shown in Figure E -16. Figures
E-17 and E-18 present some miscellaneous reactions involving potassium
oxide (gas) and beryllium compounds. Figure E-19 contains some reactions
of arsenic and antimony compounds. The oxidation of antimony sulfide
proceeds readily in the pretreater while the sulfate is readily reduced in
the hydrogasifier. Arsenous oxide (As,03' gas) is thermodynamically
stable with respect to its sulfide in the HYGAS unit. Arsenous 5ulfide
(As,S3' liquid) is stable with respect to its oxide in the CO-shift reactor.
Considering several other arsenic-related reactions, however, the metallic
form (As 0) predominates in all reaction units.
The calculations presented in Table E-l comprise the thermodynamic
operating conditions in each of the process units for selected reactions.
The derivation of these values is presented and substantiated in Appendix F.
Table E-2 contains the results of computer and other calculations to
determine the equilibrium constants for the elements in numerous reactions
at various temperatures.
Elements not considered in this table, because
only limited thermodynamic data are available, include germanium, samarium,
and ytterbium. Chlorine, fluorine, nitrogen, and sulfur are not directly
presented because the reactions include them as chlorides, fluorides,
ammonia, and sulfides.
E-23
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
*
Table E-1. CALCULATED VALUES OF OPERATING REGIONS
Pretrea.ter (700K}
MS -1- 3/2 Oz 4t MS03
MS03 + l/2 Oz it MS04
JParameter 1
[1/ P 3/ Z] **
Oz
[ 1 / P rlz ]
O2
[ 1 / P 0/ ]
[P tiP 3/2 J
SOz Oz.
[ 1 / P CO: ]
[PS02 ]
MS -- 202 +! MS04
MS -:.3/2 O2 i! MO + S02
MO + COz +t MC03
MSOl i! MOz + S02
HTR, OG (1300K ); CO-Shift (600K)
MS 1- H2 ~M(s, g) + H2S
MO + Hz tM(s, g) + H20
[PHZS/PHZ J
[PH20/PH2 J
[PH2S/PH20J
[PH2S/P CO2, PHzoJ
[PH203/P H23 J
[PH204/PH24 ]
[ 1 / P CO2 ]
[PH20/PHClz ]
[PH2S/PHC12 ]
[PH20/PHF2 ]
[PHzS/ PHF2 J
MS 1- H20 i! MO + H2S
MS -1- COz + HzO i!MC03
+H2S
MSOJ + 3Hz ;!MS + 3HzO
MSo.~ + 4Hz t MS + 4HzO
MO + CO2 t MC03
MO + 2HCl i! MClz + H20
MS ,. 2HCl it MClz + HzS
MD -.- 2HF i! MF 2 + H20
MS + 2HF ;t MF2 + H2S
HYGAS
-1. 25
-0.093
-1.16
-2.33
- 0 . 280
-0.374
-1.17
3.82
2.67
5.82
4.67
Log [ J
1. 02
0.34
1. 36
- 1. 14
1. 20
- 2. 16
CO-Shift
-1.25
0.348
-1. 60
-2.70
1. 04
1. 39
-1.097
.1. 19
2.59
6. 19
4.59
*
. Bitur.ninous Coal.
*-)(- 21 % 0z is in the pretreater air.
t Based on Pretreater off-gas composition Table 1, Part 3, Column D.
E-24
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
z
U>
-t
-t
C
-t
m
o
"T1
"
»
M
I
tV
U"1
U>
-t
m
()
:I:
z
o
r
o
"
-<
Table E-2,
Pa rt 1.
Antimony.SbzS, (See Figure E-19.)
SbzS, +9/2 0z ;!SbzO, +3S0z
SbzS, + 30, ;!2Sb(s) + 3S0z
Sb,S, + 30z ;! 2Sb( g) .+ 3S0,
Sb,S, + 30, ;! 1/2 Sb,(g) + 3S0,
SbzS, +3H,0 ;! Sbz0 ... 3H,S
Sb,S, ... 6HCI ;! 2SbCI, + 3H,S
Sbz0, + 6HCI ;!2SbCI, + 3HzO
Sb + 3HCI ;! SbCl, + 3/2 Hz
Sb(g) + 3HCI ;!SbCI, + 3/2 H,
Sb, (g) + 12HCI ;!4SbCI, + 6H,
SbZOJ + 3Hz i! 2Sb + 3HzO
SbzO, + 3H, ;!2Sb (g) + 3HzO
SbzO, + 3Hz ;!1/2 Sb.(g) + 3HzO
Sb,S, + 3H, ;! 2Sb + 3HzS
Sb,S, + 3H, ;! 2Sb(g) + 3H,S
SbzS, + 3H, ;! 1/2 Sb,( g) ... 3H,S
Arsenic, FeSz. FeAsz (See Figure £-19. )
As'" 3/2 H, ;! AsH,(g)
AsZO) + 3Hz i! 2AB + 3HzO
As,e, + 6H, ;! 2AsH,(g) + 3HzO
As,e, ...6HCI ;!2AsCI, ... 3H,0
AsH, + 3HCl ~AsCl, + 3Hz
As + 3HCI ~ AsCI, + 3/2H,
Barium (See Figures E-l to £-4, £-7.
E-8. E-I0, E-12. and E-14 to E-16.)
Beryllium (See Figures £-1 to £-4, £-7,
E-8, E-I0. E-12 to E-14. E-16. and E-18.)
Bismuth, BiZS)
BiZO) +3H,.S i!BiZSJ +3HzO
Bi,S, ... 3Hz ;!2Bl(g) ... 3HzS
BizS, ... 3H, ;! 2Bi(t) ... 3HzS
Blz0, ... 3Hz;! 2Bi(g) ... 3HzO
Bi,O, ... 3Hz ;! 2Bi(~) + 3HzO
THERMODYNAMIC EQUILIBRIUM CALC ULA TIONS OF LOG K
eq
Temperature, K
..I2.qQ
1200
.!..!QQ
.!.QQQ.
-.--.
3.704
-I. 758
5.609
-I. 967
6.238
-1.915
5.229
-6. 309
3.065
900
800
log K eq
-9.241
-3.723
-I. 354
-21. 7
-4.019
-5.222
15.004
2.584
16.942
WITH TEMPERA TURE
700 600 500 400 ~ OC
.......
93.6 --:J
0-
54. 933
29.753
51. 348
-10.44 -12.041
- 3.888 - 4. 148
6.552 7.893
- 0.8445 - 0.383
11. 746 12.092
3.792 8.136
9.399 8.659
-16.939 -22.987
4.656 3.825
- 2.199 - 3.382
-27.379 -35.028
- 5. 784 - 8.216
- 5. 752 - 6.484
10.683 13.858
-2.285 -I. 229
-0.895 1.893
0.72 I. 561 2.948
5.764 -5.9825 -6.2765
17.749
21. 047
0.599
0.4
18.348
- 0.868
- 2.585
20.0
B75030438a
ex>
...0
~
\..V
-------
z
CI>
-I
-I
C
-I
m
o
."
(;)
»
CI>
-I
rr.
n
:I:
z
o
r
o
(;)
-<
Table E- 2,
Pa rt 2.
THERMODYNAMIC EQUILIBRIUM CALCULATIONS OF LOG Keq WITH TEMPERATURE
M
~
N
0'
Temperature. K Q:)
1300 1200 1100 1000 900 800 700 600 ill 400 298 ...........
::'':''''''''' u\C~n)i3 I?g K"q -J
B,O, +4HCI +H, ;! 2BCI,{g) +3H,O -22.471 -46.765 -55.96 0'
B,O, + 4HF +H, ;!2BF,(g) + 3H,O -13.951 -31.271 -37.924
Calcium (See Figures E-l to E-4, E-7.
E-8. E-IO. and E-12 to E-16.)
Cadmium, CdS
CdS + 3/2 0, ;!CdO +SO, 26.036
CdS + 0, ;! Cd +SO, 12.203
CdS + 20, ;!CdSO. 39 . 805
CdS +H,O ;!CdO +H,S - 5.204 - 8.644 -10.039
CdS +H,O +COz ;!CdCO, + H,S -30.393 -28.944 -28.634
CdO +CO, ;! CdCO, -25.003 -20.3 -18.595
CdS + 2HCI i'CdCI, +H,S - 2.145 - 0.483 0.47
CdO + 2HCI i'CdCl, + H,O 3.059 8.161 10.509
Cd +HzS ~CdS +Hz 1. 597 6.841 8.434
Cd +1/20, ;!CdO 13.833
CdSO. + 4H, ;! CdS + 4H,O 16.2E 22.739 25.199
Chlorine
Chromiwn
Cobalt, CoS
CoS04 +4Hz i!Co5 +4HzO 17.072 ll.144 24.791
CoS + HzO ;! CoO + Hz5 -1. 8n - 4.349 - 5.223
CoO +2HCl +!CoClz +HzO --{).168 3.lZ6 4.805
CoS +ZHCl ~CoClz +HzS -2.04 - 1. 123 - 0.418
Copper, CuS
CuS +20z :CUS04 34.731
Cu,S + 5/2 Oz ;'CuSO. + CuO 37.683
CuS +3/20, ;'CuO +SOz l5. 746
CuS04 +4Hz t!CuS +4HzO l7.813 31.117
CuSO. + 4CO ;! CuS + 4COz 31.517 48.697
CuS +H, ;!Cu(s) + H,S 0.484 - 0.426
CuS +HzO i!CuO +HzS -4.912 -10.363
Cu,S + H, ;'lCu(s) +H,S -2.758 - 4.579
CUz5 +HzO ~CuzO +HzS -6.821 -12.404
CuD + Hz i!Cu +HzO 5.396
B75030438b
00
...0
~
v.J
-------
z
en
-I
-I
c:
-I
m
o
."
C'I
>
en
-I
m
()
::I:
z
o
r
o
C'I
-<
Table E-2,
Pa rt 3.
THERMODYNAMIC EQUILIBRIUM CALCULATIONS OF LOG Keq WITH. TEMPERATURE
CP
-
-.J
J'
2CuO +HzS + H,. i!CuzS +2HzO
CUzO +Hz t!2Cu +HzO
CUzS + HzS t!2CuS +Hl
CUzS +ZHCl i! ZCuCI +HzS
CUzS +ZHF i!ZCuF +HzS
CUzS +4HCI i!ZCuClz + Hz +HzS
CuzS +4HF i!2CuFz +Hz +HzS
Fluorine
Germanium
M
I
tV
-.J
1300
gQQ.
1100
Temperature. K
~O- 900
6.775
- 0.075
- 3.726
- 4.Z93
-ZO.103
- Z.Z67
- 1. 814
- o. 51Z
- 5.437
- 3.758
6.Z37
log K eq
800
600
400
Iron. FeCO,. FeSz. FeO
FeSz + 30z t FeSO. + SOz
FeSz + 0. ~ FeS + So.
FeSz + 5/Z Oz i! FeO + ZSo.
ZFeSz + I I /Z 0. i!FezO, +4S0z
3FeSz + HOz ~ Fe)O. + 650z
FeCO, ;! FeO + Co.
ZFeCO, + I/Z Oz ;! FezO, +ZCOz
FeSz +Hz ;! FeS +HzS
FeS +Hz ;!Fe +HzS
FeS + HzO ;:! FeO + HzS
FeS +HzO +COz ;! FeCD) + HzS
FeSz + Hz + HzO . Co. i! FeCO, + ZHzS
FeS + ZHCI i! FeClz +HzS - Z. 3Z5
FeSz + 4HCI i! FeCl,(g) + ZHzS + I/Z Clz
FeS +ZHF i! FeFz + HzS - 8.457
FeSz +4HF i! FeF,(g) + ZHzS + I/Z Fz
FeO + ZHCI i! FeClz +HzO
FeO +ZHF i! FeFz(g) + HzO
FeO + 3HCI i! FeCI,(g) + HzO + I/Z Hz
Fe + I/Z Oz i!FeO
FeSO, + 4Hz i! FeS + 4HzO
FeZO) + 2HzS + Hz ;! 2FeS + 3HzO
700
500
-17.872
-ZI.446
IZ.ZZ7
0.314
- 3.727
- 3. 449
-51.785
-18.055
-ZI.987
6Z. 5Z 3 75.636
19.308 Z 1. 899
50.845 59.4Z5
57.78 68.IOZ
55. 959 65.776
3.376 Z.963
10.816 11. 641
O. Z64 - 0.551
- 4.343 - 5. 108
- 3.143 - 3.618
-IZ.571 -IZ.356
-19.55Z -ZO.OZ5
- 0.089 1.009
-15.589 -18.651
- 5.651 - 4.674
-26.584 -31.459
3.054 4.6Z7
-11.4Z -13.5Z7
- 5.341 - 5.959
16.836
19.ZZ4 Z 1. 037
8.041 8. 573
1175030438c
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Table E- 2,
Part 4.
THERMODYNAMIC EQUILIBRIUM CALCULATIONS OF LOG K
eq
Lead. PbS
PbS -+ 20~ i! PbSO,.
PbS. 3,2 O! +' PbO(g\ + SO,
PbS .. O! ~ Pb + SO!
PhS -+H20... C02 i!PbC03 +H!S
PbO +CO,+'PbC03
PbS ..H20 ~ PbO(g) +H!S
PbS "H20 ~PbO(s) +H!S
PbS .. H2 ~ Pb(t) + H,S
PbS . 3n H2 ~ PbH(g) ... H,S
PbS ..2HCl +,PbCl,(g) + H25
t':I
I
N
00
PbS ""ZHF -: PbFz +-HzS
PbS.. 3/2 O2 .. PbO(s) + SOz
PbSO.; +- 4Hz" PbS ... -lHzO
Pb" 1/2 0, ;! PbO(g)
FbO(s) +' PbO(g)
Pb + 1/2 0, ;!PhO(s)
Lithium (See Figures E-5. E-6, E-9.
E-l 1. E-14. and E-15.)
~....lagnesium (See Figures E-l to £-4. E-7,
E-S. E-IO. and E-12 to E-16.)
~angaI1ese MnCO). MnOz
M.nC03 +HzS i! MnS ....COz -+ H20
MnC03 i! ~1nO ""COz
MnO +H,S ;!MnS"H20
MnSO.. ""4Hz ~ MnS +4HzO
~1nC03 -+ 2HC 1 i! MnG 12 + H20 + COl
MnO+2HCI;!MnCI, + H20
:\1.nC03 .... 2HF i! MnFz ..... H20 + CO2
MnO +lHF .. MnFz + Hz 0
MnS -+ lHCl t!'MnClz +HzS
MnS -+ lHF ~ MnFz + HzS
Temperature. K
~ .vv ~"" ~ ~ ~
- log K eq
42.731 52.913
15.469
15.445
-30.267 -30.142
-22.078 -20.676
-19.212 -23.754
- A. 189 - 9.466
- 3. 599 - 4. 584
-16.737 -20.552
0.809 1.974
- 2.018 - I. 418
26.491
19.813 21.861
0.023
-II. 023 -14.288
II. 046 13.811
L.;JVV
iZvv
1 ivv
14.987
-31.133
-26.716
- 6.697
- 4.417
- 0.998
- 6.404
- 1.197
- 3.157
13.395
- 2.37
3.677
2.167
4.962
I. 027
3.935
18. 592
6.073
5.042
4.181
- 0.384
4.565
20.286
6. 554
6.938
2.622
3.006
2. 373
16.202
0.54
- 1.918
- 1.627
- 4.085
2.671
1.64
I. 107
- 2- 295
- I. 559
WITH TEMPERATURE
c:.
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'0'
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Table E-2,
Pa rt 5.
THERMODYNAMIC EQUILIBRIUM CALCULA TIONS OF LOG Keq WITH TEMPERA TURE
Mercury. Hg. HgS
HgS + 3/2 Hz i!HgH + HzS
HgO + HzS i! HgS + HzO
Hg(g) + 1/2 Hz .. HgH(g)
HgS +HzO i!HgO(g) +HzS
HgS +2HF i!HgFz(g) +HzS
HgS +2HCI i!HgClz + HzS
HgO(g) + 2HF i! HgFz + HzO
HgO(g) + 2HCI i! HgClz + HzO
HgS + Oz i!Hg + SOz
HgS + 3/2 Oz i!HgO(g) + So.
HgS + 3/2 Oz i!HgO(s) +SOz
HgO(s) i!Hg(g) + 1/2 0,
HgO(g) i! Hg(g) + 1/2 0,
HgO(s) i!HgO(g)
Hg + I /2 Oz i! HgO(g)
HgO(s) +2HF i! HgFz + HzO
HgO(s) +2HCI i!HgC!z+HzO
HgS.. Hz i!Hg(g) +H,S
HgO(s) +Hz i!Hg + H,O
HgFz +H, i! Hg(g) + 2HF
HgCI, +Hz .. Hg(g) + 2HCl
Molybdenum, MOZS)
Mo,S, .. 6H,O i! 2MoO, + 3H,S + 3Hz
MoSz + 2HzO it MoOz + 2HzS
MaS) + 3HzO ~ MoO) + 3HzS
Mo,S, + 3H>.0 i! 2MoO + 3H,S + I /2 0,
MoZS) + 4HzO t! 2MoOz + 3HzS + Hz
Temperature. K
1300
1200
1100
.!.QQQ.
900
- 8.28
- 4.403
3.225
2-3
13.79
5.162
800
log Keg
700
-13.26
8.835
-14.35
-15.147
-17.244
- 3.502
- 2.097
11. 645
20.134
19.545
20.845
- 0.711
0.601
- 1. 312
- 0.601
- 3.47
10.333
1. 05
14.925
18.334
4.592
-25.836
-18.61
- 9.904
-110.316
-57.781
00
--
-.J
0'
600
500
400
298
-16.57
16.182
-16.783
-19.08
-19.216
- 4.381
- O. 138
14.697
- 3.034
11. 801
0.213
16.395
19.429
4. 594
-29.553
-20.385
-12.151
-132.843
-66.28
B75030438e
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Table E-2, Part 6. THERMODY NAMIC EQUILIBRIUM CALCULATIONS OF LOG Keq WITH TEMPERATURE
.00
Temperature, K .........
Z -J
l1QQ II 00 1000 900 HOO 700 600 500 400 298 0"
VI 1200
-i Nickel, NiS. NiCO,. Ni,S, log Keg
Ni +1/2 O2 i! NiO 13.147
Ni,S, + 7/2 °z i! 3NiO + 2S0, 70.718
-i . Ni3Sz + 9/2 Oz ~ 2NiS04 + NiO 93.674
C NiS + 202 i! NiS04 48.748
NiS04 + 4Hz t NiS + 4HzO 24.342
-i 3NiSO. + 13H z~ Ni3Sz + 12HzO + HzS 50.235 63.436 70.127
m NiO + HzS ~ NiS + HzO 6.431
NiO + Hz t Ni + H20 2.083 2.489 2. 591
Ni)SZ ... 3HzO i! 3NiQ + 2HzS + Hz -10.131 -14.278 -16.394
NiO + CO2 t NiCO) -17.086
Ni3Sz + 2Hz i!3Ni + 2HzS - 3. 369 - 6.811 - 8.621
0 Ni + HzS i! NiS + Hz 3.843
NiS + 2HF t! NiFz +HzS - 3.169
"TI NiS + 2HCl i! NiClz + HzS - 2.293
NiO + 2HF i:! NiFz + HzO - I. 883 I. 881 3.262
NiO +2HCI i!NiCI, +H,O - 1.132 2.61 4.138
Ni3Sz + 6HF i!' 3NiFz + ZHzS + Hz - 8.635 - 6.608
Q M Ni,S, + 6HCI i! 3NiCI, + 2H,S + H, - 6.448 - 3. (78
I
W 3NiS i! Ni3Sz + S - 6.606
» 0 NiS + CO2 + H20;:! NiC03 + HzS -29. 988
VI
Nitrogen~ Organic
Potassiwn (See Figures £-5, E-6,
E,9, E-II, E-14, E-15, E-17)
Samariuxn
-i Selenium. SeS. FeSe,
Se + H, i! H,Se(g) - 0.022 - 0.174 - O. 328
m Se,(g) + 2Hz i! 2H,Se(g) 0.844 2. 535 3.782
Se + 6HF ~SeF6 + 3Hz -51. 665 -57.781 -62.338
()
Se,(g) + 12HF i! 2SeF, + 6Hz -97.844 -112.805 -123.895
J: SeHz + 6HF ~ SeF 6 + 4Hz -59.993 -67.561 -73.238
Z Silicon, 5i02
SiO,(s) i!SiO(g) + 1/2 Oz -18.749 --16.346
0 SiO, + 2HzS i! 2H,O + SiSz(s) -10.43 -19.306 -22.509
r SiO, + 2Hz i! Sits) + 2H,O -13.066 -27.19 -32. 39
SiO, + 4H. i! SiH.(g) + 2H,O -19.034 -33.S38 -39.312
0 SiO, + H,S + H, i! SiS(g) + 2H,O -11. 91 -30.984 -37.977
Q SiOz + 4HF i! SiF4 + 2HzO - O. 367 3. 56-1 4.933 00
SiO, + 4HCI i! SiCI.(g) + 2HzO - 9.B96 -1-1.495 -1&.193 ...0
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Table E-2,
Pa rt 7.
THERMODYNAMIC EQUILIBRIUM CALCULATIONS OF LOG Keq WITH TEMPERATURE
(X)
-
-.J
0'
Sih'cr. Ag. AgS
!A~+l'.!O.-:Ag!O
2Ag + II~S t! A~zS + 1I.~
Ag!S + 20;: i! AgzSO..
A~.!SO.. + 4H, ~ AgzS + -tHzO
A~;:O + 2HF t! !.AgF + 11;:0
AgzO + lliCI t ZAgCI ... HzO
Ag;:S + ZHF -: 2AgF + H;:S
Ag;:S + 2HCI .. 2AgCl + illS
Ag.;:O + COz i!A)!2:CO,
Ag,S + H,O + COz ;! Ag,Co, I H,S
AgzO + HzS ~ AgzS + IIzO
AgzS + Hz i! ZAg + IlzS
AgCI + III H, ;!HCI + Ag
AgF + 1/2 H;: t!!-tF + A~'.
Sodiwn (See Figures E-S, E-6,
E-9. E-ll. E-14. E-1S)
~
I
W
......
Strontium (See Figures £-1 to E--I. £-7.
E-I{, E-IO, and E-ll t.o E-16.)
Sulfur
TeHurium. FeTez. TeS
Te + Oz -: TeO;:
Te(g) + 0, .. TeOz
Te,(g) + lO, ;! lTeOz
Te(s) + 6HF .. TeF,,(g) + 3H,
Te(g) + 6HF ;! TeF,,(g) + 3H,
Te,(g) + IlHF ;! lTeF" + 6Hz
Te + -tHCI ~ TeCL.. + 211z
Te(g) + 4HCI ;! TeCI, + lH,
Te,(g) + HHCI ;! lTeC\, + 4Hz
TeOz + 6HF t! TeFl, + 2HzO + Hz
TeOz + -tHCl .. TeCt.. + lHzO
TeOz + 3Hz t! TeH;: + 2HzO
Tin, SnCO" SnS" SnS
SnS + 3/Z 0, ;! SnO + SO,
5nS + lOz .. SnOz + SOz
SnS, + 51l Oz ;! SnO + lSO,
5nSz + 30;: i! SoOz + 250z
I ~OO
1. Ill}
-27.37
-58.5
-11.351
-l().46l
-- ---- ---
7. 371
10.21K
-10. III
-13.73
-II}. 196
- l. HI4
Ilon
------. -- ------- ---'~.sn~~~~~~ -~ - --
I 1nn I non '100
.----- -----
- ---- --- -_._-- -
- O. 'IIH
4. <).I'}
.----------------
Hon
-Ioj!, \":'<,'q - -.
------------ - ------------------
..- -..,-.----., .---- ---
--- - --..-------.-.- -- .-.-
- ---------
100
600
400
500
-- O. I. 37
O.I:}')
O. ~3(,
0.31l
- l..lI,3
10.1.03
:\ j. K(,l
l.061
l3.4(,'1
-17. .1"<;
- l.077
-1'1.17
- I. 3l
l3.705
- 0.53(,
0.3'll
H. .10 J
". 317
1 r;. 7i, ~ I'!. 033
l.l. 5(,3 l'l.l3l>
1<;. 545 H.OKI
-3H.OII -11. 301
-30.211 -I I. O'JK
-7"/...003 -7(,. SK7
-IH.416 -}'I. H2.H
-10. i,Ii, - ". l,l5
-31..HI.I '-3.1. (,41
-ll. r;o.? -l2.947
-- l. 1)07 - 1.47H
15.154
31. III 37.03')
4H. (,15 57. 161
<;0.45 ::;9, j~J4
73.lll HC" .$H(I
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2.'JI-;
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Table E-2,
Pa rt 8.
THERMODYNAMIC EQUILIBRIUM CALCULATIONS OF LOG Keq WITH TEMPERATURE
5nS + H20 i! SnO + HzS
SnS + H, ;! Sn(I.) + H,S
5nSz + Hz ~ 5nS + HzS
5nSz + Oz t! 5nS + SO~
SnO + 1/2 0, ;! SnOz
SnS + 2HCI ;! SnCI,(g) + H,S
SnS + 4HCI ;! SnCI.(g) + H,5 + H,
5nSz + 2HCl + Hz +=!SnClz + 2HzS
5nSz + 4HCl i! SnC14 + 2HzS
5nSz + Hz + H20 t! SnO +2HzS
5nS, + 2H,0 ;! 5nO, + 2H,S
SnO + H20 ~ SnOz + H1.
Sn + H20 ~ SnO + Hz
5n + co., ;! SnO + co
Titanium. TiOz
TiOz + 2HzS t! TiSz + ZHlO
TiO, ;! TiO + 1/20.,
TiOz +2Hz t!Ti + ZHzO
TiOz +HCI + 1/2 H, ;!TiOCl(g) + H,O
TiO, + 2HCl .. TiOCI,(g) + H,O
TiO, + HF + 1/2 H, ;! TiOF(g) + H,O
TiO, + 2HF ;! TiOF,(g) + H,O
TiO, +4HF .. TiF.(g) +2H,0
TiOz + 4HCl i! TiC14 + 2HzO
Vanadium. (Organic)
2V + 5/2 O2 t! VzOs
2V + 3/2 0, ;! V,O,
V,O, + 3H, + 4HCI .. 2VCI, + 5H,0
V,O, +2H, + 6HCI ;! 2VCI,(g) + 5H,0
V,O, + H, + 8HCI ;! 2VCI. + 5H,O
V,O, + H, + 4HCl .. 2VCI, + 3H,0
V,O, + 6HCl ;! 2VCI, + 3H,0
V,O, + 8HCI ;! 2VCI.(g) + 3H,0 + H,
Ytterbium
Temoer;:tt.u.,.".. K
00
-
1300
1000
298
1200
1100
- 2.295
- I. 274
- I
- I. 627
- - 6
- 1.39
- I. 513
.- 2.033
- 0.52
- 1.021
- 0.741
-11.682
-14.259
-14.852
- 9.595
-14.497
- 9.104
- 2.93
- 6.354
- 0.816
-II. 718
- 9.46
-20.362
900
800
log K eq
700
600
-J
0'
500
400
- 3.569
- 3.991
0.295
19.331
17.504
- I. 609
- 5.56
- I. 314
- 5.265
- 3.274
- I. 406
1.868
-12.547
-26.34
-29.609
-33.450
-21. III
-32.734
-20.128
- 2.433
- 8.H2
93.656
77.83l
7.496
0.307
-10.906
- 7.452
-15.141
-26.354
- 4.105
- 5.101
- 0.095
22. 355
20.173
- I. 167
- 5. 362
- I. 262
- 5.457
- 4.200
- 2.771
1.429
0.996
0.399
-14.651
-31.629
-35.225
-40.228
-25.328
-39. 382
-24.048
- 2.288
- 9.228
10.709
3. 139
-II. 147
- 6. 756
-14.326
-27.416
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Table E-2,
Pa rt 9.
THERMODYNAMIC EQUILIBRIUM CALCULATIONS OF LOG Keq WITH TEMPERATURE
1100
Temperature. K
1000 900 800 700 600 SOO
log K eq -
40.42 50.017
29.142
8.378
-10.666 -12.856
- 5.538 - 6.467
-29.016 -28.742
-23.478 -22.275
- 2.221 - 1.734
- 3.573 - 3.044
3. 317 4.733
1.965 3.423
20.764
22. 124 24.757
2.307 4.949
-11.408 -12.807
298
1300 1200
Zinc, Zn5
ZnS + 20z 4! ZnSO" 16.691
Zn5 + 3/2 0, ;!ZnO + SO,
ZnS + Oz i! Zn + SOz
ZnS + Hz" Zn ~.HzS -A.021
ZnS +HzO ;! ZnO + HzS - 2. 959
ZnS + HzO+ COz .. ZnC03 +HzS -30.269
ZoO + COz ~ ZnC03 -27.31
Zn5 +2HCl .. ZnC1, + H,5 - 1.947
ZnS + 2HF i! ZnFz + HzS
ZnO + 2HC1 .. ZnCl, + H,O 1. 012
ZnO + 2HF t! ZnFz + HzO
Zn + 1/2 Oz ;! ZnO
ZnSO-, + 4Hz;! ZnS + 4HzO 15.039
Zirconium, ZrSi04
ZrO, + 4HF .. ZrF.(g) + 2H,0 - 2.393
ZrOz + 4HCl .. ZrC1.(g) + 2H,0 - 7.643
400
- 3.608
- 2. 745
B75030438i
00
..........
--J
0'
00
-.0
~
VJ
-------
8/76
8943
By comparing the equilibrium constants for each element and reaction
with thl~ corresponding value of the operating region, the more stable form
of the dement can be determined. At 700K, the value of log K for the
eq
reaction -
CdS + 3/2 O~ t CdO + SO~
is 26.036. The corresponding operating region value for the pretreater at
700K if: -1. 14 (see Table E-l). Obviously, cadmium oxide is much more
stable under these conditions than cadmium sulfide.
The results of comparing operating region values with the equilibrium
values for the elements are summarized in Table E-3. The thermodynam-
ically dable form of cadmium in the pretreater is the sulfate. In general,
oxide and sulfate forms are stable in the pretreater, while sulfides and
elemen~al forms are stable in the hydrogasifier and CO-shift reactors.
By combining the thermodynamic data for each element, it is possible
to dete)~mine what compounds will be favored in each reactor and, hence,
to what extent each trace or minor element will be removed from the product
gas str eam. The solubilities, vapor pres sures, and other physical properties
were uBed to evaluate the removal of pollutants downstream from the reactors.
Across the periodic array of elements, the trend is for first-and second-
period elements to be stable as carbonates; the elements of periods 3B, 4B,
and 5B to be more stable as oxides; and the rr£ tals to be more stable as
sulfide1i up through the transition elements. Heavier metals (e. g., mercury,
lead, b.ismuth) tend to exist in elemental form. Hydrides form with members
of the carbon, nitrogen, and oxygen families.
It 1s assumed that the scrub units are highly efficient in particulate
removal and that the operating temperature of each unit is relatively uniform.
The ga~ residence time in the light-oil vaporizer 1s assumed to be sufficient
to condense all condensable materials (such as volatilized metals) on the
fluidized drying bed. The materials passing overhead from the cyclone to
the CO.. shift reactor are assumed to be gaseous and contain only small
quantities of minute particulates. Some condensable materials may be
transported on these entrained particulates.
E-34
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76 8943
Table E- 3. THERMODYNAMICALLY STABLE FORMS OF
ELEMENTS IN THE PROCESS UNITS
::~ '- -'-
Element Pretreater HYGAS ,- CO-Shift-"
Sb SA S S
As SA E,H E,H
Ba SA C C
Be 0 0 0
Bi SA E, S E, S
B 0 F F
Cd SA S S
Ca SA S C
Cl E HCl ECl
Cr SA S S
Co SA S S
Cu SA S S
F E HF HF
Ge 0 H H
Fe SA S S
Pb SA S S
Li 0 C C
Mg SA S C
Mn SA S S
Hg E E, S E
Mo SA S S
Ni SA S S
N E,O H H
K 0 C C
Sm 0 0 0
Se 0 H H
Si 0 0 0
Ag SA S, E E
Na 0 C C
Sr SA C C
S 0 H H
Te 0 H H, E
Sn 0 E, Cl Cl
Ti 0 0 0
V 0 0 0
Yb 0 0 0
Zn SA S S
Zr 0 0 0
-'-
" C = carbonate; E = element; H = hydride; 0 = oxide; S = sulfide;
and SA = sulfate.
E-35
INSTITUTE
o F
GAS
TEe H N 0 LOG Y
-------
8/76
8943
APPENDIX F.
EXAMPLE OF OPERATING-REGION DETERMINATION
The operating regions for the different reactions may be determined
from the gas compositions in each reaction unit. These values are calcu-
lated in the tables and indicated on each figure where applicable by a labeled
circle. The basis for the calculations and concurrent assumptions about
operating regions lies in fundamental physical laws. For each reaction,
the change in the Gibb's Free Energy value (6G) can be related to the
equilibrium constant (K ) by the equation
eq
AG::: -R T J nK
eq
where R is the gas constant, and T is the absolute temperature of the
system. The equilibrium constant can be calculated for gas phas e reactions
by measuring the composition of the gaseous products at the end of a reac-
tion which began with known quantities of reactants. This type of test and
analysis has been done on a large number of reactions, the results of
which are tabulated and published in numerous references. 5,17, ~1-~3, ~6, ~7, 38,
4l ,61 , 63,64
For a typical gas phase reaction the equilibrium constant can be
written:
K
eq
:::
[p CJc [PDt
[p Ja [p Jb
A B
where the bracketed quantity represents the partial pressure (in atmospheres)
of the products or reactants at equilibrium. Each quantity is raised to the
power of its stoichiometric coefficient.
Equilibrium constants of heterogeneous gas reactions (gas -solid, gas-
liquid) are somewhat more complex than gas -phase reactions requiring
the additional concept of activity. The equilibrium constant for the reaction
MS (s) + HlO(g) ~ MO (s) + H~S(g), takes the form:
K
eq
::: [aMO ] [PHzS ]
CaMS ] [PHlO J
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where 1Ja" is the activity of the solid phase component. Solid phase activities
are us.~ally assumed to be near unity to expedite calculations, hence, the
equilibrium constant can be determined from the partial pressures of HzS
and Hz':) in the reaction vessel at equilibrium. If the vapor pressure of the
solid or liquid components is calculable at the reaction temperature, the
partial pres sure should be useq in the calculation of K .
. eq
In this study, the mole percentages of the gaseous components in the
main reactors are as sumed to be constant during steaQy-state operation.
Thus, in the hydrogasifier, the value of [PHzSJ / [PHzOJ is a constant.
Since E is known from previous calculations, the ;ratio of products (s olid)
eq
to rea<:tants (solid) can be determined directly. This provides the thermo-
dynamJ,cally favored form of the element for tla. t reaction in that reactor
unit. The concept of operating regions is derived from this treatment.
T1:.e operating region for the rea(::tions of Figwre E-l may be calculated
from the mole fraction data of Table 1, Par~ 3, Column D (pretreater off-
gases)u The operating region at 700K may be calculated as log [I/(PO)3/Z],
which follows from the form of K for these reactions;
eq
K - JaMSO) 1
eq - ~
CaMS] [p Oz ] /z
In this case, PO =0.21 atm and log [l/(PO )%] = 1.02. The K values
2 2. eq
are much higher than 1.02 in these reactions, and the thermodynamic driving
force bods strongly to the right, favoring oxidation to sulfites. Had the
operating region been greater than the K values, the driving force would
eq
have boen to the left, favoring redp.ction to sulfides.
The assumption that the mole fraction of a component in a gas is equal
to its partial pressure is supported in the following discussion.
Partial-Pres sure Calculations
The Ideal Gas Law states that the mole fraction of a gas is directly
proportional to its partial pres sure:
P.
1
PT
==
n.
1
I;n.
1
- X
- i
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At low pres sures and high temperatures one ma y readily calculate the
partial pressure of a component in a gaseous mixture. This law was applied
to the gases in the HYGAS reactors to estimate the partial pressures needed
to calculate the operating regions for the different reactions.
Calculations were based on 100 atm pressure in the hydrogasifier and
CO-shift reactor-. Thus, the mole percent of a gas in the hydrogasifier was
numerically equal to its partial pressure: e.g., for HzO, 17.81 mol '70
indicates a partial pressure of 17.81 atm. Since the HYGAS process is
designed to operate at pres sures ranging from 70 to 100 atmospheres, 100
atm was chosen over a median value for convenience. Pretreater calcu-
lations were based on 1 atm pressure.
The validity of the Ideal Gas Law at these conditions was checked by
calculating the reduced pressure and temperature for each process gas and deter-
mining the compressibility factor (2) and fugacity coefficients (f/p) from
generalized tables. The values of 2 and f/p are listed below. Because
the values are all very near 1.0, the assumption holds.
* t f/p
T P T P Z
c c r r
CO 134.15 35 8.94 2.57 0.997 1.002
C02 304.25 73 3.9 1.2 1.000 1.000
H2 34.25 12.8 35.04 7.03 1.09 1.09:j:
H20 647.3 218.4 1.85 0.412 0.989 0.984
CH4 190.65 45.8 6.29 1. 97 0.996 1.000
H2S 373.55 88.9 3.2 1. 01 1.000 1.000
* T = 1200K/T .
r c
t P = 90 atm/P .
r c
:j: Each table listed T maximum as 15.00. T for hydrogen here is 35. 04.
r r
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APPENDIX G.
BASIS FOR CALCULATIONS
The objective of the present study is to prepare an environmental test
plan to investigate the fate of constituents of coal and potential pollutants
during coal gasification. The basis for this test plan is the analytical data
acquired from four series of gasification runs in a 0.1 m diameter reactor
of the HYGAS process development unit. The operating conditions of these
runs were 1160K (1630 OF) and 6935 kN/m~ (1006 psia). The gasification
runs did not include a steam-oxygen gasifier, nor were there any gaseous
or liquid samples tested, since the gasification runs were conducted a few
years prior to this program. The net carbon gasified in these runs was
about 40%.
Some comments should be made on the applicability of these test data
and operating conditions to a commercial design. First, one may expect
more extreme conditions to be experienced in a commercial plant. The
steam-oxygen gasifier will produce much higher temperatures than the
present tests have reached and will cause more materials to be volatilized.
Indeed, the amount of carbon gasified should exceed 90% of the original
coal feed. Second, a commercial plant will most likely operate at higher
pressures than these bench-scale tests. This will allow for pressure
drops across the system to supply product gas at a nominal 6995 kN/m2
(1015 psia) rate without the need for additional compression. Third, the
coal-feed and ash-discharge systems are quite different. The bench-scale
reactor is dry-fed and dry-dis charged; the commercial plant will incorpor-
ate a slurry feed system using either a light oil or water as the slurry
medium. Ash material will be slurried and discharged in a similar manner.
The slurry medium presents another sink for the soluble trace-elements
which may tend to accumulate with time. This factor is not encountered in
the bench-scale tests and may prove to be a significant part of the total
potential pollutants to be carefully studied.
The differences between the bench-scale reactor runs and a commer-
cial plant operation are many, and yet the data derived from the former may
with justification be scaled-up to the latter. First, we must be cognizant
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of the differences between the PDU and the commercial plant and of how they
affect the actual operations. Second, the thermodynamic differences, as
they re]ate to trace-element volatilization and reactions, must be considered
with thE proces s. changes. Third, the information gathered from analys es
of the bench-scale gasification runs is the most complete look available
at the fc!.te of trace elements during hydrogasification. The importance of
gatherilLg additional data in a comprehensive program to evaluate the
environmental impact of coal-gasification processes cannot be overemphas-
ized. Our current work indicates that the purification units connected with
a HYGAS plant will eliminate the toxic trace-elements, but further assur-
ances are required for the private as well as public acceptance of a new
energy 30urce.
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TECHNICAL REPORT DATA
(Please read IIlUTuctiolls all the rel'erse before completing)
1. REPORT NO. 12. 3. RECIPIENT'S ACCESSION' NO.
EPA-600/2-76-259 .
4. TITLE AND SUBTITLE INITIAL ENVmONMENTAL TEST 5. REPORT DATE
PLAN FOR SOURCE ASSESSMENT OF COAL GASI- September 1976
FICA TION 6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO.
A. Attari, M. Mensinger, and J. Pau
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
Institute of Gas Technalagy lAB013; ROAP 2lADD-024
3424 Sauth State Street 11. CONTRACT/GRANT NO.,
Chicago., illinais 60616 68-02-1307
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORi/~ND PER/~D COVERED
EPA, Office af Research and Develapment Task Final. 6 73-12 74
Industrial Enviranmental Research Labaratary 14. SPONSORING AGENCY CODE
Research Triangle Park, NC 27711 EPA-ORD
15. SUPPLEMENTARY NOTES IERL-RTP praject afficer far this repart is W. J. Rhades, Mail
Drap 61, 919/549-8411, Ext 2851. 16. ABSTRACT Th t d .b . Tit. tit t I
e repar eSCrl es an Inl la sa'Jrce assess men enVlronmen a es p an,
develaped to. investigate the fate a~ varia'Js ca:1stituents during caal gasificatian. The
plan is an appraach to. the prablems assaciated with sampling paint selectian, sample
callectian, and sample analysis which is based on a HYGAS-type pracess. The
repart includes a general pracess descriptian, process steps, effects af aperating
conditians, sampling, analytical methads, and significance af results. In arder to.
be implemented, this enviranmental test plan wauld have to. be integrated into. the
operating pragram of a specific facility. Although this integratian has nat taken
place, it wa~lld be a next step taward data acquisitian.
17. KEY WORDS AND DOCUMENT ANAL YSIS
a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDECi TERMS c. COSA TI Field/Group
Air Pallutian Air Pallutian Cantrol 13B
Caal Gagificatian Statianary Saurces 13H
Assessments Saurce Assessment 14B
Tests Test Plan
Sampling HYGAS Pracess
Analyzing
18. DISTRIBUTION STATEMENT 19. SECURITY CLASS (Tllis Report) 21. NO. OF PAGES
Unclassified 145
Unlimited 20. SECURITY CLASS (Tllis page) 22. PRICE
Unclassified
EPA Form 2220.1 (9.73)
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