AbstractThe best known commercial coal gasification processes which use oxygen (air) and steam as gasifying media are the gas producer process (normal pressure, fixed bed), Lurgi process (high pressure, fixed bed), Winkler process (normal pressure, fluidized bed) and Koppers‐Tetzek process (normal pressure, entrained). Fixed bed and fluidized bed processes are suitable for gasification of noncaking and weakly caking coals with high ash fusion temperatures (> 1200°C). The entrained system is suitable for gasification of any coal.Low‐caloric gas (∼ 150 Btu/scf) can be produced by the gas producer, Lurgi and Kinkier processes; medium‐ (∼ 300 Btu/scf) and high‐caloric (∼ 950 Btu/scf) gas by any process. Lurgi and Koppers‐Totzek processes are preferred processes for production of synthesis gas at the present time.The costs (/Btu) of production of low‐caloric gas are the lowest followed by the medium‐ and high‐caloric gas costs (see Figure 6). The costs of gas production from coal are mainly dependent on the efficiency of the gasification process, scale of operation and the cost of fuel.