Published: December 2007
Coal gasification is becoming industrially important worldwide to chemicals production from synthesis gas together with cogeneration of electric power; the United States and China are most important in this developing industry.
PEP Report 154A, Coal Gasification (December 2006), provides screening-level technoeconomics of industrial grade syngas using the Shell Coal Gasification Process (SCGP) sized for production of 5,000 metric tons per day (MT/day) of methanol using the ICI process (412 million SCF per day syngas 2 H2: 1 CO). Report 154A discusses gasification industry developments through 2006; Report 154B updates this through 2007.
This PEP Report 154B adds screening-level cost estimates for the GE/Texaco and the ConocoPhillips E-Gas coal gasification processes. All of these gasifiers can be classified as high pressure, oxygen blown; pulverized-coal entrained flow gasifiers but have differing geometries, operating pressures and quench mechanisms. Another difference is that in the GE/Texaco and Conoco/Phillips systems the coal is fed to the gasifier as pumpable water slurry whereas it is a pneumatically conveyed dry solid in the Shell system. They produce differing raw gas compositions which require varied follow-on CO/H2 adjustment and cleanup processing schemes to produce the chemical grade syngas.
Many options exist for the cleanup processing schemes. The scheme evaluated in this study includes sour gas shift, Selexol for H2S/CO2 separation and sulfur recovery via Claus/SCOT. The base plants are designed for processing ~278 (dry basis) metric tons per hour (MT/h) of Illinois No. 6 bituminous coal and producing ~530 Nkm3 /h (449 MM SCF/day) of syngas suitable for methanol synthesis together with ~199 Nkm3 (169 MM SCF/day) of captured CO2 suitable for disposal via sequestration.
Plant capital and operating costs are important in the comparisons; ultimately, however, the comparative plant availability of these three gasifiers becomes the most important factor. Gasifier availability data published through 2007 is discussed.
This report should be useful to planning and evaluation groups.