Crude hydrogen and methanol prodn. from synthesis gas - comprises methanol synthesis in plant main stream before carbon mon:oxide conversion

摘要

MeOH synthesis is effected before CO conversion, in crude H2 and MeOH prodn. from a synthesis gas contg. mainly C oxides and MeOH, by a process comprising CO conversion, CO2 scrubbing and MeOH synthesis. MeOH synthesis gas mixt. opt. contains recycled gas in addn. to fresh synthesis gas, provided recycle:fresh synthesis gas quantity ratio is 2. Exclusive use of fresh synthesis gas for MeOH synthesis is prefd. In pref. synthesis gas, mol. ratio H2:CO is 0.8:1 to 1.5:1. Plant and process costs are reduced. MeOH prodn. is increased. The unreacted gas mixt. is processed to crude H2 which can be worked up to pure H2, e.g. for NH3 synthesis. Crude MeOH obtd. has a lower water content.