Simultaneous removal of H2S and SO2 from tail gases

A process for removing sulfur compounds from a gas, comprising:

• a) providing a sorbent, comprising;
• expanded perlite, a substitutional solid solution characterized by the formula NiZZn(1-Z)Al2O4, and a substitutional solid metal solution characterized by the formula NiAZnB,
• wherein A is a numerical value is in the range of from about 0.70 to about 0.98, and B is a numerical value in the range of from about 0.03 to about 0.30;
• b) contacting the sorbent with a reducing agent in a reduction zone,
• wherein as a result of said contacting, at least a portion of the Ni promoter metal component of the sorbent is converted to a reduced-valence state;
• c) contacting the sorbent with a tail gas stream in a sorption zone,
• wherein said tail gas comprises sulfur dioxide (SO2) and hydrogen sulfide (H2S), and
• wherein H2S present in said tail gas reacts with said Ni promoter metal to produce NiS, and SO2 present in said tail gas reacts with NiS in the presence of a reducing agent to form NiS2,
• wherein said contacting simultaneously reduces the quantity of SO2 and H2S present in the tail gas, thereby generating a sulfur-laden sorbent;
• d) regenerating at least a portion of said sulfur-laden sorbent with a regeneration gas stream in a regeneration zone to produce a regenerated sorbent and an off-gas stream comprising SO2;
• e) returning at least a portion of said regenerated sorbent to said sorption zone of step c) for a subsequent contacting step;
• f) routing at least a portion of said off-gas stream comprising SO2 to an off-gas user.