The processes listed in Table 9.4 that are reported to be used commercially to supply synthesis gas for methanol production are the Lurgi process, the

Winkler process, the Koppers-Totzek process, and the Texaco process. Down­stream adjustment and treatment of the raw product gases is required when these processes are used to supply feedstock or cofeedstock to a typical low — pressure methanol process operating at 220 to 270°C and 5.066 to 10.132 MPa (50 to 100 atm). A few of the operating details of these and other commercial coal gasification processes are presented here.

Dry Ash Lurgi Process

This process is a fixed-bed process that gasifies crushed, dried coal at 620 to 760°C, 2.43 to 3.14 MPa, and residence times of about 1 h. The raw product gas exits the gasifier at 370 to 590°C and contains tar, oil, naphtha, phenols, ammonia, sulfides, and fines. Quenching with oil removes tar and oil. Catalytic shifting and scrubbing of the quenched product gas provides a gas that can be methanated to produce substitute natural gas, or the equivalent of pipeline gas. The process is limited to noncaking coals.