COAL GASIFICATION ONLY REASONABLE WHEN PLANT IS INTEGRATED

COAL GASIFICATION ONLY REASONABLE WHEN PLANT IS INTEGRATED SOME PROCESSES ARE COMMERCIAL H 2 S REMOVAL BY THE CLAUS PROCESS H 2 S + O 2 = H 2 O + SO 2 H 2 S + SO 2 = S + H 2 O

Energy Content Summary…. Type Producer Gas Water Gas Low-Btu Intermediate-Btu SNG Methane Btu/SCF 90 -120 341 150 260 -300 950 1054

Probable Uses…. • Low-Btu gas – Local electrical power generation – Cannot be used for home or commercial heating • Intermediate-Btu gas – Electrical power generation – Feed stock for chemicals – Town gas • High-Btu gas…. Same as natural gas

Selection of a Gasifier • Type of bed • Operating pressure • Slagging, non-slagging Lurgi (fixed bed, high P, non-slagging) Koppers-Totzek (entrained bed, low P, slagging) Wellman-Galusha (fixed, low P, non-slagging) Winkler (fluidized, low P, non-slagging)

CO 2 25, 303 TPD @ 8, 920 Btu/lb FEED COAL H 2 S+CO 2 GAS LIQUOR COAL PREPARATION OXYGEN-BLOWN COAL GASIFIERS SCRUBBING AND COOLING CRUDE GAS SHIFT CONVERSION H 2 O+CO=H 2+CO 2 RECTISOL GAS PURIFICATION SULFUR PLANT METHANATION 3 H 2+CO=CH 4+H 2 O ELEMENTAL SULFUR * 128 LTPD COMPRESSION AND DEHYDRATION TARRY GAS LIQUOR OXYGEN STEAM COAL FINES STEAM AND POWER PLANT OXYGEN PLANT ELECTRIC POWER TO PLANT USE PIPELINE GAS 290 MMSCFD @ 950 Btu/Scf OILY GAS LIQUOR N 2 AIR GAS LIQUOR SEPARATION AND EFFLUENT WATER TREATMENT RECLAIMED WATER TO PLANT USE NAPHTHA COAL TAR COAL OIL TOTAL LIQUIDS 8940 BBLS/day PHENOLS AMMONIA Figure 7 -6. Pipeline gas from coal via Lurgi pressure gasification. 155 tons/day

Figure 7 -11. The Texaco gasifier (also Shell, Eastman)

System for In-Situ Gasification of Coal Inject air and steam Produce low-Btu gas Chemical reactions From Wiser, 2000

Financial Dilemma • Synthetic natural gas cost - >$10. 00/106 Btu • Investment - 75 x 1012 Btu/year plant, 30 year life - $8 billion • Benchmark is cost of oil and gas energy sources - Need a floor on the price of energy over a long time frame