Shift conversion of raw gas from gasification of coal

摘要

In a process for producing a fuel gas from a solid fuel by a gasification of solid fuel under a pressure of about 15-100 bars by a treatment with steam and a gas which contains free oxygen, cooling the raw gas to a temperature of about 150°-200° C. and saturating it with water vapor, removing condensate which has formed so that the raw gas contains hydrocarbons having a boiling range from about 20° to 400° C. in an amount of about 10-100 g per standard m.sup.3 of dry gas and has a CO:H.sub.2 O volume ratio of about 0.8-2, and subjecting the raw gas to a shift conversion, the improvement which comprises dividing the raw gas into first and second partial streams in a ratio of about 1:10 to 1:1, feeding the first partial stream with a surplus of water vapor to a first shift conversion stage at an inlet temperature of about 280°-450° C., and passing through a second shift conversion stage a mixture of effluent gas from the first shift conversion stage and at least part of the second partial stream of raw gas at a temperature of about 300°-500° C., while maintaining a pressure of about 15-100 bars in the shift conversion stages. Advantageously water vapor is added to the raw gas entering the first shift conversion stage in at least about 70% of the stoichiometric amount required for shift conversion of all the carbon monoxide contained in the entire raw gas.