Desulphurization and partial carbon dioxide removal - treatments for natural and refinery gas

摘要

Grid gas supply is prepd. by desulphurising natural gas under pressure, refinery gases and/or gases obtained by cracking or gasification of hydrocarbons with steam and/or O2, while removing only part CO2, and leaving gas containing =3 vol % CO2, takes place by process where CO2, is partly removed at 110-160 (pref. 140-150) degrees C with a bicarbonate-contng. aqs. alkali carbonate soln. circulated over absorber and regenerator, amount and bicarbonate content of which is measured so that its uptake capacity is just sufficient for scrubbing excess CO2. Contact time between gas to be treated and washing solution is controlled so that COS is completely saponified and part of the H2S is washed out, whereupon the gas is subsequently desulphurised almost completely with fresh or regenerated alkali carbonate soln. at temps below 100 degrees C.