Sulfur recovery process using metal oxide absorbent with reducing gas purge

Process for the recovery of sulfur from a H.sub.2 S containing gaseous stream comprising:

• (a) converting H.sub.2 S to elemental sulfur by the Claus reaction in a Claus furnace and producing an effluent stream comprising both H.sub.2 S and SO.sub.2 ;
• (b) removing both H.sub.2 S and SO.sub.2 from the effluent stream by reaction in a first absorption zone with a sorbent containing ZnO, optionally after converting substantially all sulfur species to H.sub.2 S, thereby producing ZnS and an absorber effluent stream comprising H.sub.2 and CO;
• (c) regenerating ZnS to ZnO in a second absorption zone by admixing O.sub.2 with at least a portion of said absorber effluent and introducing the resulting stream containing from about 0.4 to about 3.5 mol. % O.sub.2 into contact with ZnS in the second absorption zone, thereby producing regenerated ZnO and a regeneration effluent stream;
• (d) conditioning the regenerated ZnO from step (c) by introducing at least a portion of absorber effluent, without oxygen, into contact with the regenerated ZnO in the second absorption zone;
• and
• (e) interchanging the first absorption zone and the second absorption zone and continuing steps (b), (c), and (d);
• wherein
• step (d) is conducted for a period of time effective for reducing by at least 10% a temporary increase in emissions of SO.sub.2 otherwise occurring from the second absorption zone after the first and second absorption zones are interchanged in the absence of step (d).