RECOVERY OF SO2 FROM WASTE GAS EMISSIONS

摘要

A process for recovering sulfur values from gas emissions by absorbing SO2 in an aqueous solution comprising a mixture of Na2HPO4 and NaH2PO4 at a pH between about 2.5 and about 5 at an absorption temperature between about 85 DEG and about 200 DEG F., treating the phosphate solution containing absorbed SO2 with H2S to produce sulfur, separating the sulfur from the phosphate solution and recycling the phosphate solution to the absorber. Provision is made to remove sulfate, which builds up in phosphate absorbent, by crystallizing sulfate from a purge stream. The process is particularly useful in the field of pollution abatement for recovering SO2 from the off-gas obtained from a Claus-type reactor system.