Carbonyl sulfide removal from gas mixture comprises use of regenerated active carbon granules of defined pore size

摘要

Carbonyl sulfide (COS) is removed in a first stage process from gas by an active carbon filter in the presence of molecular oxygen and ammonia. The active carbon is then regenerated and treated again. The first-stage active carbon has pores whose average accumulated pore volume is at least 0.8 cm<3>/g. 10-30 % of the first-stage carbon has pore diameters between 350 and 1200 nm. At least 40% of the first-stage carbon grains have pore sizes of less than 10 nm. The first stage carbon grains have an average overall accumulated pore volume of at least 1.2 cm<3>/g. 15-25% of the first stage overall pore volume is in the range 350 to 1200 nm. At least 55% of the first stage carbon grains have a pore size of less than 10 nm. The final stage carbon is regenerated by washing with preferably water followed by steam cleaning followed by drying by dry carbon dioxide containing ammonia.