Trace-Element Geochemistry of Coal Resource Development Related to Environmental Quality and Health (1980)

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6 SYNTHETIC-FUEL PROCESSES (LIQUEFACTION, GASIFICATION) AND COKE PRODUCTION FROM COAL Through thermal processing, coal may be converted from a solid to hydrocarbon liquids and gases, which are cleaner and more conveniently handled. These products are referred to as synthetic fuels (or synfuels). Coal can also be processed thermally to produce a solid, high-carbon coke used commercially to reduce iron ore to metallic iron. Because the coking operation is basically similar to proposed pyrolysis processes for synfuels production, it is also dealt with in this chapter. Although commercial coking processes have operated for almost 100 years, little information about the fate of trace elements in coking operations has been made available to the public. No large commercial synthetic fuel plants are operating within the United States, and only a few are operating elsewhere. There is little available information about the fate of trace elements in such processes. Within the United States, however, there are many research programs devoted to the development of synfuel processes, and from some of these programs a small amount of data has begun to emerge. This chapter discusses the unit operations characteristic of the synfuel processes (some of which are similar to those in the coking processes) and their potential for concentrating or emitting trace elements. In addition, the sparse data that are available have been summarized or referenced. SYNTHETIC-FUEL PROCESSES When coals are heated in the virtual absence of free oxygen to about 400•c and above, they pyrolyze or decompose. Lower-molecular-weight substances evolve as volatile matter, leaving a residual char or coke. The carbon-rich char or coke may be used as a fuel for combustion or as a carbon source for steam gasification (C + H1 0 + heat --> CO + H1 ) or as a reducing agent for the production of iron from its ore. A portion of the volatile matter can be condensed and recovered as liquid tars or oils. If the coal is slurried in a hydrocarbon oil and then heated under pressure, the same basic chemical reactions take place. However, in this process, referred to as liquefaction, substantially more of the 103 

104 coal is converted to liquids that may then be separated from any unliquefied coal. These operations are shown schematically in Fiqure 16. The pyrolysis process operated at 400-soo·c can be considered a means principally for obtaininq liquids from coal (althouqh a substantial proportion of residual char is also recovered); when carried out at about lOOO"C with a premium cokinq coal, its principal purpose is to produce coke for the smeltinq of iron ore in a blast furnace (althouqh some tar by-products are also recovered). Coal or char may be fed to the qasification process; with coal, the volatile products would be converted to qas (thouqh condensible liquids could be recovered dependinq on the reactor desiqn). The undissolved coal from the liquefaction process is normally ash rich; the orqanic content of this fraction depend~ on the severity of the liquefaction process and the procedure used to separate the liquids from the residue. This residue can be pyrolyzed to recover additional liquids, it can be burned as fuel, or it can be disposed of. From all the processes, there is normally an aqueous liquor produced by condensinq steam that is formed in the process. Fiqure 17 is a schematic flow plan showinq the major unit operations in a typical coal liquefaction plant. The process includes a qasifier to convert carbon from unliquefied coal to qas; by followinq the coal preparation flow and the flow of streams into and out of the qasif ier block, the flow plan for a "stand alone" qasifier plant can be envisioned. The coker in Fiqure 17 can be reqarded as a pyrolysis reactor; thus, from the flow throuqh this system, a pyrolysis plant or cokinq operation can be inferred. Cokinq and synfuel processes (i.e., pyrolysis, qasification, and liquefaction) share a number of common unit operations that could concentrate or evolve trace elements. These unit operations are shown in Fiqure 18 and are listed in Table 44. Commonly, a qasification plant will produce tars as a by-product, and invariably a liquefaction plant will contain a qasifier to produce hydroqen or fuel qas. In addition to the operations unique to cokinq and synfuels production, coal storaqe and handlinq processes and furnace-flue-qas emissions are similar to those discussed in the sections of the report for utility plants. SYNTHETIC-FUEL EFFLUENT STREAMS Commercial slot-type coke ovens emit volatile pyrolysis products (tars, qases) durinq charqinq, throuqh leaks in the oven, and durinq coke discharqe and quenchinq operations. The fate of trace elements durinq these phases of operation is unknown. In contrast, synthetic-fuel processinq occurs in closed and sealed systems, as in petroleum refinery operations. However, as with any process, there are specific effluent streams. The effluent streams in which trace elements could be emitted to the environment are shown in Fiqure 18 and are listed in Table 45. Whether the trace-element content of any particular stream represents a potential hazard to the environment depends on three factors: the trace-element content of the prepared feed coal, the specific processinq conditions, such as temperature and pressure (affectinq the conversion 

105 ~ Light gases <COx, CH4, H20, ,....._ __,.Volatile ....tcondenlser H2S ,etc.) Matter •---""'·- - ----t., Liquid Hydrocarbons Coal Char or coke <To furnace, gasification,ore smelting) PYROLYSIS PROCESS Char (c ~ ash) ---d_.1000°C 700 - Steam .___ _.._Ash GASIFICATION PROCESS Light gases <COx, CH4, H20, etc.> Liquid Hydrocarbons 400- Coa I ----,--.... soo•c Solvent Recycle Hydrocarbon Solvent '----+-_. Undissolved coal <To disposal or pyrolysis process) LIQUEFACTION PROCESS FIGURE 16 Schematic description of principal coal-conversion processes. of trace elements to labile forms), and the control measures exerted to reduce emissions. Effluent streams that have the potential for being especially troublesome and that are unique to synfuel processes are the following: • The quenching and disposal of gasifier ash. Conceivably, the chemical forms of trace elements in gasifier ashes could be different from those. in furnace ashes, because the gasifier atmosphere is reducing whereas the furnace atmosphere is oxidizing and is generally at a higher temperature. No data bearing on this question are available. • Gas scrubber water and condensate. Sparse data that are available (Forney et al., 19751 Sharkey et al., 1975) indicate that treated product gases may be essentially free of metallic elements. Normally, 

106 Ash-rich Refuse GAS Recycle t H/C Liquids Naphtha Recycle ~----,,---.Solvent ~ (Dtstlllatlon)--+ To SI ~ ToU~ ~ Solvent !Heavy Mi~ From ~ To u"=\?" Dlsttllation Air ..., ~Fuel z iii ... "' .... Ash-rich Char GAS () (Gasit)~ If Process Water Air---- Air From GAS Units FIGURE 17 Flow plan showing major unit operations in a typical coal liquefaction plant. Effluent streams in which trace elements might leave the plant are indicated by heavy-lined boxes. those trace elements that are volatilized in the gasifier (possibly cadmium, chlorine, fluorine, mercury, sulfur, selenium, tellurium, and zinc) could be expected to be trapped in the gas condensate liquor and the acid-gas removal system. However, until current research develops appropriate methods of treatment, inadequately treated gases that are burned hot (i.e., in an adjacent utility plant) could contain volatile elements that would be emitted to the atmosphere. The aqueous condensate liquor from coking plants probably would be similar to gasifier liquors. Treatment of this stream will be critical to the quality of effluent waters • • Acid-gas removal system. Amine or carbonate systems to remove acid gases might collect trace elements not condensed in the aqueous 

107 r::) \2 to 16 Dust ® Ill" 1 ¢ Effluents To Pr-Unit •s1rwms likely 10 be unique 10 1Ynfuel1 . , , . _ c:ompered 10 1imiler petroleum operetlons. tReector (1191116) m-v be llquefec:tlon reector, glliflmtlon reector, or pyrolyli1 (coking) reector end UIOCieted aperations equipment. FIGURE 18 Unit operations in liquefaction and gasification plants. The applicability of specific unit operations to specific processes is given in Table 44. liquor, which could result in disposal problems for this stream. Although there are no data available to indicate that such a phenomenon would occur, power-plant scrubbers using lime or limestone to remove S01 do not appear to trap noxious trace elements (V. E. Swanson, Geological Society of America, Boulder, Colorado, personal communication, 1977). • Tail gas from sulfur plant. All synfuel processes are likely to produce sulfur as a by-product. Though this is common practice in petroleum refineries, the feed-trace-element contents differ. Coal trace elements might produce unique problems in sulfur plants associated with synfuel installations because of the significantly greater amounts of trace elements in coal than in petroleum; though here also, no data are available • • Catalyst disposal. Catalysts employed to upgrade coal liquids will likely concentrate some trace elements. Disposal of used catalysts could present unique problems related to the fate of the trace elements. • Product liquid utilization. Many trace elements indigenous to the feed coal will be found in product hydrocarbon liquids from coal liquefaction. Their ultimate fate will depend on the final use of the 

108 TABLE 44 Unit Operations in Coking and Synfuels Plants a Liquefactionb Operation Coke Plant Gasification 1. Coal storage x x x 2. Coal drier x x 3. Coal pulverizer x x x 4. Pretreater furnace s 5. Preheater furnace x 6. Reactor x x x 7. Liquids upgrading x s x 8. Gas scrubber x x G 9. Acid gas removal x x G 10. Methanation/shift x 11. Catalyst regenerator s x 12. Oxygen plant s 13. Sulfur plant x x 14. Utility boiler x x 15. Cooling tower x x 16. Wastewater treatment x x x 17. Feed-water treatment x x x 18. Ash disposal x G a s, some plants. bG, part of gasification plant to supply hydrogen for liquefaction process. liquid, which is a legitimate concern in any consideration of synfuel processes. No published data have been found for trace-element contents of coking plant streams, though some information may exist in company files and government agencies concerned with occupational safety. Only a limited number of references to trace elements in synfuel processes could be found. Table 46 presents a list sununarizing synfuel-related trace-element data sources; a sununary af the data for the elements is presented in Tables 47 through 51. Other than the references listed in Table 46, no publications, of the many addressing trace elements in synfuel processes, report specific data. However, general discussions of the subject from the viewpoints of numerous authorities may be of interest. Therefore, those publications that have been consulted in the preparation of this chapter but that are not specifically cited are listed in the bibliography at the end of the chapter. 

109 TABLE 45 Unit Operation Effluents and Products in Most Coking and Synfuels Processes Effluents and Products From Unit No.a Dust 1, 2, 3, 18 Leachate 1, 18 Water vapor 2, 15 Flue gas 2, 4, 5, 11, 14 Hydrocarbon liquids 7 Carbon dioxide 9 Product gas 10 Used catalyst 11 Tail gas 13 Sulfur 13 Cooling-tower discharge water 15 Ammonia 16 Sludge 16, 17 Water (treated) to pond 16 Quench vapor 18 aAs listed in Table 44. The only reference encountered that discusses methods for dealing with trace-element effluents is an Environmental Impact Statement for a proposed gasification facility (U.S. Bureau of Reclamation, 1977). However, because no data are supplied, it is unclear whether the procedures will be applicable. Few generalizations about the fate of trace elements in the many synfuel processes being investigated can be provided from available published data. Especially critical is the inability to predict how selected trace elements are likely to partition into specific streams in any process. Research programs devoted to the establishment of generalizable data are required. The major areas that should be investigated, using a variety of coals containing various concentrations of trace elements, are the following: • The effect of process variables (atmosphere, temperature, pressure) in gasification on the partitioning of trace elements among the gas stream, condensates, and the residual ash. · Methods for treating condensate and scrubber streams from gasification processes. The leachinq of trace elements from disposed qasif ier residues. • The partitioning of trace elements between products and residues in liquefaction and pyrolysis processes. 

110 TABLE 46 Sources of Trace-Element Data Pertaining to the Synfuels Process Table Reference Process Stream Liquefaction 47 Coleman et al. (1976) Concentration of trace element in solvent refined coal (SRC) 47 Jahnig and Magee (1975) Concentration of trace element in solvent refined coal (SRC) 47 Schultz et al. (1977) Concentration of trace element in synthoil 47 Given et al. (1975) Concentration of trace element in coal-derived oils 48 Griffin et al. (1978) Concentration of trace element in H-coal bottoms 48 Jahnig and Magee (1975) Percentage of feed elements in SRC 48 Schultz et al. (1977) Percentage of feed elements in product oil, centrifuge residue, and scrubber effluent Gasification 49 Sather et al. (1975) Concentration of trace element in Lurgi residue ("ash") 49 Griffin et al. (1978) Concentration of trace element in Lurgi residue ("ash") 49 Sather et al. (1975) Loss of trace element through Lurgi gasifier 49 Attari et al. (1975) Loss of trace element through hygas gasifier 50 Sharkey et al. (1975) Concentration of trace element in synthane condensate 50 Baria (1975) Percentage of feed elements in synthane condensate 50 Forney et al. (1975) Percentage of feed elements in synthane condensate, tar, char, and fines 50 Somerville et al. (1977) Percentage of feed elements in Lurgi ash, oil, tar, and liquor Table 52 shows the scale of the process that would likely be necessary to investigate the areas mentioned above. Relatively small- scale batch processes would serve in some instances, whereas continuous process units would be required in others. Some data applicable to synfuel processes could be obtained by studying process streams from commercial coke plants. HEALTH EFFECTS Coking Moat of the nation's coke is produced in Northern Appalachia and the Central regions (Appendix AJ Drysdale and Calef, 1977). Aside from 

TABLE 47 Synfuels Trace-Element Concentrations in Solvent Refined Coal, Synthoil, and Coal-Derived Oils Process: Solvent Refined Coal (SRC) SRC Synthoil Unspecified Bench-Scale Process Stream: Product SRC Product SRC Product Oil Product Oils Coal: Pittsburqh 8 Unspecified Western Kentucky Homestead Utah Illinois 6 Kentucky Concentration: ppm ppm ppm ppm Element Reference: Coleman et al. (1976) Jahniq and Maqee (1975) Schultz et al. (1977) Given et al. (1975) Antimony - 0.3 Arsenic - 0.5 Beryllium - 0.4 - 4 x 10-4 0.01 9 x 10-4 Boron - 51 - 0.15 0.12 0.03 Cadmium <0.07 <0.1 0.8 Chromium 5.9 0.9 7.6 0.05 0.12 0.05 .... .... .... Copper <9.5 2.5 2.7 0.02 0.03 0.01 Iron 423 161 Lead <0.5 0.4 1.1 Manganese 21.6 1 11 0.05 0.12 0.05 Mercury - 0.01 Nickel 23 4 6.6 0.15 0.08 0.03 Selenium - <l Tin - 9 Vanadium - 16 - 0.06 0.25 0.004 Zinc 7.6 3 - 0.12 0.12 0.05 

TABLE 48 Synfuels Trace-Element Concentrations and Percentage of Feed Elements in Other Liquefaction Processes Process: H-Coal Solvent Refined Coal Synthoil Stream: Vacuum Bottoms Product Produc.t Centrifuge Residue Effluent coal: Illinois Unspecified Western Kentucky Homestead Concentration: LoglO ppm Percent of Feed Element in Streama Percent of Feed Element in Stream Reference: Griffin et al. (1978) Jahnig and Magee 11975) hnia Maaee (1975) Schultz et al. (1977) Antimony <l 2 Arsenic 1-2 4 Beryllium 1-2 58 Boron 3-4 80 Cadmium <l 5 37 65 0.3 Chromium 2-3 2 48 75 1 .... .... Copper 1-2 78 31 74 2 ..., Iron >4 <l Lead 1-2 3 33 77 3 Manganese 2-3 4 30 70 0.03 Mercury <l 75 Nickel 1-2 6 63 72 0.2 Selenium 1-2 21 Tin <l 14 Vanadium 2-3 7 Zinc 2-3 12 aBased on assumed yield of 75 percent (solvent refined coal), dry coal basis. ' / j 

TABLE 49 Synfuels Trace-Element Concentrations in Lurgi Residue and Losses Through Lurgi and Hygas Gasifiers Process: Lurgi Lurgi Lurgi Hy gas Stream: Residue ("ash") Residue ("ash") Loss Through Gasifier Loss Through Gasifier Coal: Illinois 5 Illinois 6 Unspecified Illinois 5a Illinois 6a Unspecified Concentration: ppm ppm Weight Percentb Weight Percent Element Reference: Sather et al. (1975) Griffin et al. (1978) Sather et al. (1975)a Attari et al. (1975) Antimony 0.3 0.2 1-10 91 81 33 Arsenic 0.3 0.1 1-10 98 99 65 Beryllium 21 13.7 10-100 6 - 18 Boron 673 622 100-1000 79 Cadmium <0.3 <0.3 <l - - 62 Chromium 570 755 100-1000 0 0 0 .... .... Copper 273 239 10-100 0 0 - w Iron 15 x 10 4 5.2 x 10 4 104 0 0 Lead 210 71 10-100 32 - 63 Manganese 320 200 >1000 0 0 Mercury 0.01 0.02 <l 99.5 99.6 96 Nickel 462 456 10-100 0 0 24 Selenium - - <J, - - 74 Tin Vanadium 181 301 100-1000 19 0 30 Zinc 15~8 4.7 100-1000 29 0 aBased on residue representing 9.43 percent and 11.1 percent of dry feed coal (from ash balance calculation). bWeight percentage of trace elements in feed not found in ash-rich residue. 

TABLE 50 Synfuels Trace-Element Concentrations in Synthane Condensate and Percentage of Feed Elements in Related Gasification Processes Process: Syn thane Syn thane Syn thane Stream: Condensate Condensate Condensate Tar Char Fines Coal: Illinois 6 Concentration: ppb Percent of Feed Element in Stream Percent of Feed Element in Stream Element Reference: Sharkey et al. (1975) Baria (1975) Forney et al. (1975)a Antimony - - 0 0 203.1 2.0 Arsenic 30 0.06 0.2 3.0 116 4.3 Beryllium - - 0 0.2 138.4 4.2 Boron - - 75.7 0.9 95.1 0.6 Cadmium - - 0 1.4 404.1 10.4 Chromium 6 0.02 0 0.2 48 0.4 ...... Copper 20 0.09 0 0.3 29.8 1.1 ... ...... Iron 3 x 10 7 Lead - - 0.1 1.2 656.4 5.1 Manganese 40 0.21 0.1 0.1 43.7 0.0 Mercury - - 39.9 19.6 15.7 1. 2 Nickel 30 0.13 0.1 0.3 55.7 1.0 Selenium 360 9.23 11. l 0.5 310.5 9.9 Tin 20 0.70 0 0.2 68.9 2.6 Vanadium 3 0.005 0 0.1 53.4 0.9 Zinc 60 0.1 0.1 0.1 71.9 0.6 -- aAverages of three runs. Elemental balances range from 48 to 660 percent. J t 

115 TABLE 51 Distribution of Selected Inorganic Trace Elements from Mercer County Coal, Indianhead Mine, North Dakota, During Sasol Gasification Test of a Lurgi GasifierCI Parts per Percentage of Feed Element in Streanl"•c Million Gasifier Element in Coal Ash Oil Tar Liquor Sb 0.3 100 As 8 90.8 3.2 4.3 1. 7 Be 0.3 99.1 0.9 B 56 99.3 0.03 0.03 0.7 Cd <l 14.5 1.6 4.5 79.4 Cr 5.3 97.7 0.3 1.8 0.2 Cu 10.6 93.5 0.7 5.3 0.5 Fe 7936 99.0 0.02 0.95 0.01 Pb 2.7 88.3 0.7 10.9 0.1 Mn 70.7 99.2 <0.01 0.7 0.1 Hg 0.2 1.4 0.5 38.2 59.9 Ni 6.7 93. 3 0.7 5.7 0.3 Se 0.4 13.8 1.3 2.8 1.5 Sn 0.27 100 v 21.3 99.0 0.01 1.0 0.01 Zn 6.7 74.7 1.6 3.4 20.3 asource: Somerville et al. (1977). bAll elemental balances normalized to 100 percent total except selenium, which was assumed to exit with gas. cDashes indicate no data. TABLE 52 Potential Sources for Data on Trace Elements in Synfuels and Coking Process Bench Bench Pilot or Process Batch Continuous Commercial Pyrolysis partitioning x Coke plant Liquefaction partitioning x x Gasification, gas versus residue X Scrubber solutions ? x Coke plant Gasification ash leach x 

116 total particulates, inorganic emissions from coking are not well characterized, but synergistic interaction of metals with other pollutants could contribute to effects on population near the plant. As an illustration of the potential impact on local air quality, the Clairton Coke Works, largest in the country, emits from approximately 25 tons of particulates per day (Allegheny County Bureau of Air Pollution Control, 1977; Kenson et al., 1976). The elevated lung-cancer mortality rate experienced by coke workers is moat likely attributable to organics and major pollutants (Lakowicz et al., 1978; Laskin et al., 1975), although metals could play a role in potentiating and enhancing the effects of gases, organics, and particulates that workers are exposed to during the coking process. A study of 3305 workers and 6475 controls revealed 2.5 times the lung-cancer mortality expected. There was also gradation of risk with type and duration of exposure. The relative risks were 1.70 for all men with leas than 5 years' experience at the start of follow-up; 2.10 for men with 5 or more years aide-oven experience only; 3.22 for men with 5 or more years of mixed topside and aide-oven experience; and 6.87 for men with 5 or more years employed at full topside (Redmond et al., 1972). Synthetic-Fuel Plants Potential ef fecta of trace elements in synfuel plants may be considered in two categories, public health (environmental) effects and occupational health effects. Factors that could affect the routine release of trace elements to the environment were discussed in the preceding paragraphs. These may be categorized as coal-dust emissions, flue-gas emissions, and water contamination (from ash leachate and process condensate). Except for condensate water, which can be adequately treated before discharge, the potential public health effects in these three areas are expected to be only minimally different in kind (as already discussed) from those experienced as similar emissions from utility power plants. Synthetic- fuel plants will probably be quite large, consuming coal at rates equivalent to or larger than those of very large power plants. Therefore any problem related to ash disposal in synfuels plants would be at least equivalent in magnitude to the problems experienced at power plants. However, only about 10 percent of the coal consumed would be burned in a synthetic-fuel plant, meaning that flue-gas emissions would be aignif icantly lower per ton of coal consumed in synfuels plants in comparison with large utility power plants. The industrial hygiene aspects of synfuel plants will, however, differ from those indigenous to utility power plants. As has been discussed, processing is accomplished in closed systems, so that routine contact with concentrated or labile forms of trace elements will be negligible. System leaks should be minimal (comparable with experience in well-run petroleum refineries). However, because of the higher concentration of trace elements in the coal-derived synfuel in-plant process streams, any system leaks would have the potential for emitting larger amounts of trace elements than would be emitted from petroleum refineries. The concentration in some selected streams would also 

117 require that precautions be exercised durinq periods of maintenance when the systems are opened. However, it is likely that such precautions will be exercised because of the carcinoqenicity of polynuclear aromatics that are found in coal-derived hydrocarbon liquids. Distribution and utilization of the synthetic fuels should ~lso be a public health concern. Coal-derived qases will be unlikely to contain any harmful trace elements because of the procedures used to clean product qases. Hydrocarbon liquids (asphalts, fuel oils, qasolines) miqht contain troublesome trace elements dependinq on the extent of processinq to which they are subjected. Because these liquids are hiqhly aromatic, contact by workers and consumers should be minimized anyway; therefore trace-element concerns are really secondary. Combustion of the liquids would likely result in emission of contained trace elements. This matter should be considered if coal-derived liquids (except those produced by reforminq qases) are produced commercially. BIBLIOGRAPHY This biblioqraphy represents a thorouqh literature search on synthetic- fuel processes and coke production from coal. Attari, A. 1973. Fate of trace constituents of coal durinq qasification. EPA-650/2-73-004. U.S. Environmental Protection Aqency. 31 pp. Attari, A., M. Mensinqer, and J.C. Pau. 1975. Fate of trace constituents in coal qasification. EPA-659/2-73-004. U.S. Environmental Protection Aqency. Baria, D.N. 1975. Survey of trace elements in North Dakota liqnite and effluent streams from combustion and qasification facilities. Enqineerinq Exp. Station, University of North Dakota. 64 pp. Beckner, J.L. 1975. Trace element composition and disposal of qasifier ash. Seventh Synthetic Pipeline Gas Symposium, Chicaqo. Beckner, J.L. 1976. Consider ash disposal (from qasification of coal). Bydrocarb. Process. 55(2):107-109. Beychok, M.R. 1975. Perspective on coal conversion/letter. Environ. Sci. Technol. 9(5):396-397. Coleman, W.M., P. Szabo, D.L. Wooten, B.C. Dorn, and L.T. Taylor. 1976. Minor and trace metal analysis of solvent refined coal by flameless atomic absorption. Fuel 56(2):195-198. Davis, A., w. Spackman, and P.H. Given. 1976. The influence of the properties of coals on their conversion into clean fuels. Enerqy Sources 3(1):55-81. Forney, A.J., W.P. Baynes, S.J. Gasior, G.E. Johnson, and J.P. Strakey, Jr. 1974. Analysis of tars, chars, qases, and water found in effluents from the synthane process. U.S. Bur. Mines Tech. Proq. Report 76. Pittsburqh Enerqy Research Center, U.S. Enerqy Research and Development Administration. 9 pp. Forney, A.J., W.P. Baynes, S.J. Gasior, G.E. Johnson, and J.P. Strakey, Jr. 1975. Trace element and major component balances around the synthane POU qasifier. U.S. Bur. Mines Tech. Proq. Report 75. PERC- TPR-75-1. Pittsburqh Enerqy Research Center, U.S. Enerqy Research and Development Administration. 

118 Given, P.H., R.M. Miller, N. Suhr, and w. Spackman. 1975. Major, minor, and trace elements in the liquid product and solid residue from catalytic hydrogenation of coals. In Trace Elements in Fuel, S.P. Babu, ed. Advances in Chemistry Series No. 141, American Chemica1 Society, Washington, D.C., pp. 188-191. Griffin, R.A., R.M. Schuller, J.J. Suloway, S.A. Russell, W.F. Childers, and N.F. Shimp. 1978. Solubility and toxicity of potential pollutants in solid coal wastes. In Proceedings of Third Svmposium on the Environmental Aspects of Fuel Conversion Technology, Sept. 1977, Hollywood, Fla. F.A. Ayer and M.F. Massoqlia, compilers. EPA- 600/7-78-063. U.S. Environmental Protection Agency, pp. 506-518. Institute of Gas Technology. 1976. Preparation of a coal conversion systems data book. FE 2286-4. U.S. Enerqy Research and Development Administration. Jahnig, C.E. 1975a. Evaluation of pollution control in fossil fuel conversion processes. Gasification: Section 5. Bigas process. EPA- 650/2-74-009-g. U.S. Environmental Protection Agency. Jahnig, C.E. 1975b. Evaluation of pollution control in fossil fuel conversion processes. Gasification: Section 6. Hygas process. EPA- 650/2-74-009-h. U.S. Environmental Protection Agency. Jahnig, C.E. 1975c. Evaluation of pollution control in fossil fuel conversion processes. Gasification: Section 7. U-gas process. EPA- 650/2-74-009-i. U.S. Environmental Protection Agency. Jahnig, C.E., and R.R. Bertrand. 1976. Coal processing: Environmental aspects of coal gasification. Chem. Eng. Prog. 72(8):51-56. Jahnig, C.E., and E.M. Magee. 1975. Evaluation of pollution control in fossil fuel conversion processes. Liquefaction: Section 2. SRC Process. EPA-650/2-74-009-f. u.s. Environmental Protection Agency. Kalfadelis, C.D., and E.M. Magee. 1974. Evaluation of pollution control in fossil fuel conversion processes. Gasification: Section 1. Synthane process. EPA-650/2-74-009-b, U.S. Environmental Protection Agency, pp. 1-87. Kalfadelis, C.D., E.M. Magee, G.E. Milliman, and T.D. Searl. 1975. Evaluation of pollution control in fossil fuel conversion processes. Analytical test plan. EPA-650/2-74-009-1. u.s. Environmental Protection Agency. Kalika, P.w., P.T. Bartlett, R.E. Kenson, and J.E. Yocom. 1975. Measurement of fugitive emissions. Presented at 68th Annual Air Pollution Control Association Meeting, Boston, Mass. Kenson, R.E., P.W. Kalika, and J.E. Yocom. 1975. Fugitive emissions from coal. Presented at National Coal Association/Bituminous Coal Research Coal Conf. and Expo. II, Louisville, Ky. Kenson, R.E., N.E. Bowne, and W.A. Cote. 1976. The cost effectiveness of coke oven control technology--study of ambient air impact. Presented as APCA Western Penn. Section Conf., Pittsburgh, Pa. Magee, E.M. 1976. Evaluation of pollution control in fossil fuel conversion processes. Final Report. EPA-600/2-76-101. U.S. Environmental Protection Agency. Magee, E.M., H.J. Hall, and G.M. Varga, Jr. 1973. Potential pollutants in fossil fuels. EPA-R2-73-249. U.S. Environmental Protection Agency. 151 pp. Magee, E.M., C.E. Jahnig, and H. Shaw. 1974. Evaluation of pollution control in fossil fuel conversion processes. Gasification: Section 

119 1. Koppers-Totzek process. EPA-650/2-74-009-a. U.S. Environmental Protection Aqency. RRC Colllllittee on Processinq and Utilization of Fossil Fuels. 1977. Assessment of technoloqy for the liquefaction of coal. Commission on Sociotechnical Systems. Department of Enerqy Report FE1216-3. Available from NTIS, Sprinqfield, Va. 165 pp. O'Hara, J.B., S.N. Rippee, B.I. Loran, and W.J. Mindheim. 1974. Environmental factors in coal liquefaction plant desiqn. Presented at EPA Symposium on Environ. Aspects of Fuel Conv. Technol. (OCR R.D. Rep. 82. Interim Rep. No. 3, Contract 14-32-0001-1234). Ralph M. Parsons Co. Parrish, R.W., and H.B. Neilson. 1974. Synthesis qas purification includinq removal of trace contaminants by the Benfield proces~. Indust. and Enq. Chem. Div., American Chemical Society. Rubin, E.S., and F.C. McMichael. 1975. Impact of requlations on coal- conversion plants. Environ. Sci. Technol. 9(2):112-117. Rubin, E.S., F.C. McMichael, and M.R. Beychok. 1975. Coal conversion retort/letter. Environ. Sci. Technol. 9(6):497. Ruch, R.R., H.J. Gluskoter, G.B. Dreher, S.J. Russell, R.A. Cahill, J.K. Frost, J.K. Kuhn, J.D. Steele, J.F. Ashby, J. Thomas, and R. Malhotra. 1977. Determination of valuable metals in liquefaction process residues. Rep. No. 21. ERDA contract (E46-l)-8004. FE-8004- 14, U.S. Department of Enerqy. Sather, N.F., W.M. Swift, J.R. Jones, J.L. Beckner, J.B. Addinqton, and R.L. Wilburn. 1975. Potential trace element emissions from the qasification of Illinois coals. Final Rep. Proq. llEE-80.026. Rep. No. llEE-75-08. Illinois Institute for Environmental Quality. NTIS PB-241, 220/3ST. 18 pp. Schultz, B., E.A. Hattman, and W.B. Booher. 1975. Trace elements in coal--what happens to them? Amer. Chem. Soc. Div. Environ. Chem., Prepr. 15(1):196-197. Schultl, B., G.A. Gibbon, E.A. Hattman, H.B. Booher, and J.W. Adkins. 1977. The distribution of some trace elements in the 1/2 ton per day Synthoil process development unit. PERC/RI-77/2. U.S. Enerqy Research and Development Administration. 17 pp. Sharkey, A.G., J.L. Shultz, C.E. Schmidt, and R.A. Friedel. 1975. Mass spectrometric analysis of stream from coal qasification and liquefaction processes. PERC/RI-75/5. U.S. Enerqy Research and Development Administration. Shaw, B., and E.M. Maqee. 1974. Evaluation of pollution control in fossil fuel conversion process. Gasification: Section 1. Lurqi process. EPA-650/2-74-009-R, u.s. Environmental Protection Aqency, pp. 1-70. Somerville, M.B., J.L. Elder, and R.G. Todd. 1977. Trace elements: analysis of their potential impact from a coal qasif ication facility. Enq. Exp. Sta. Bull. 77-05-EES-Ol. University of North Dakota. U.S. Bureau of Reclamation. 1977. Draft environmental impact statement. ANG C~al Gasification Company, North Dakota project, Upper Missouri Reqion. U.S. Department of the Interior.