A Process for Removing Hydrogen Sulphide and Carbon Dioxide from Fuel Gases and Synthesis Gases Containing the Same

摘要

1,196,658. Purifying combustible gases. METALLGESELLSCHAFT A.G. 3 Oct., 1967 [14 Oct., 1966], No. 44924/67. Heading C5E. H 2 S and CO 2 are removed from fuel gas or synthesis gas in a process which comprises passing the gas under pressure in series through two absorbers 4, 5 (for H 2 S, CO 2 removal respectively) where the gas is contacted with an organic scrubbing liquid, e.g. methanol, acetone, toluene or xylene, at a temperature below 0‹C. Each absorber has a regeneration stage 7, 9 having flashing stages 71, 73, 91, 94, 93, and reabsorbtion stages 72, 92. Clean scrubbing liquid enters the absorber 5 at 13 and apart from a portion recycled through a cooling cycle 54, 15, the CO 2 -containing liquid is divided into two portions which re-combine at 74, namely: 16, 4, 17, 71, 22; and 29, 91 32, 93, 24, 73. H 2 and CO flashed off at 71 and 91 are returned through a compressor 6 to the gas inlet 10, while pure CO 2 flashed off at 93 leaves the apparatus at 36. The reabsorbers 72, 92 remove CO 2 from the flashed-off gases, using partly regenerated scrubbing liquid from 94, via 19, 20. The recombined liquid which still contains H 2 S, is passed via 27 for complete regeneration by boiling in column 8 and recycling through heat exchangers 85, 74, 95 to 13, gas containing H 2 S leaving at 28. Further H 2 and CO leaves at 25. Two other circuits are shown, namely line 26 for delivery of gas and vapour containing H 2 S to the absorber 7 to remove H 2 S from the gas, and line 34 for delivery of CO 2 containing liquid to flashing stage 94 and thence via 97 back to the absorber 5.