A gas refining method for adsorbing a reducing gas obtained by pressure gasification
of coal or oil comprises introducing a reducing gas stream into an adsorbing and
removing zone where it contacts an adsorbent. Sulfur-containing compounds are adsorbed
onto the adsorbent and a first oxygen-containing gas stream is introduced into
the adsorbing and removing zone in order to form a regeneration gas containing
sulfur dioxide. The regeneration gas is contacted with a second oxygen-containing
stream and a calcium-containing liquid slurry to effect absorption of sulfur dioxide
by the slurry and precipitation of a gypsum compound. The temperature of the slurry
is varied to cause selective precipitation of 60 -gypsum hemihydrate or gypsum dihydrate.
