Economic and techn. aspects of the sepn. of CO2 from synthesis gas for energy prodn. in integrated gasification combined cycle and by underground coal gasification were taken into consideration. A new concept for simultaneous sepn. of CO2, S compds. and moisture from the fuel gas (prior to combustion) by a membrane process was outlined. Selective sepn. of acid gas components in the membrane contactor resulted in redn. of plant size and improving the CO2 stream quality necessary for its sequestration in a single-stage system.