Dual-catalyst Beds to Reduce Sulfur Dioxide to Elemental Sulfur in the Presence of Water Vapor.
Sulfur Removal & Recovery from Ind Proc Adv in Chem Ser (139):15 pages
Water vapor decreases the effectiveness of an iron-alumina bifunctional catalyst in reducing sulfur dioxide with carbon monoxide. This problem can be averted by enriching the iron content in the bifunctional catalyst. The water-gas-shift reaction between water vapor and carbon monoxide generates an equivalent quantity of hydrogen. A post-catalyst bed of pure alumina must be used because of the hydrogen sulfide that is generated in the reduction step with hydrogen as well as that which is produced from the hydrolytic decomposition of the carbonyl sulfide byproduct. By deliberately releasing some sulfur dioxide (equal to half of the hydrogen sulfide produced) from the first catalyst, both pollutants can be suppressed by a claus reaction on a post-catalyst.
Sulfur Removal & Recovery from Ind Proc., Adv. in Chem. Ser., No. 139, Am. Chem. Soc., PP.60-74