Kinetic studies on the reactions involved in the hot gas desulfurization using a regenerable iron oxide sorbent—II: Reactions of iron sulfide with oxygen and sulfur dioxide

In the hot gas desulfurization process using iron oxide sorbent, the regeneration of the sulfided iron oxide sorbent consists of two reactions: the oxidation of iron sulfide with air, and its reaction with the sulfur dioxide formed during the air oxidation. This part describes the kinetic studies on the reactions of iron sulfide (formed by the reactions of Fe₂O₃ with H₂CO mixture and subsequendy with H₂S) with oxygen and sulfur dioxide. The experimental and analysis procedures used are similar to those outlined in Part I of this paper.The activation energies for the oxygen and the sulfur dioxide reactions are found to be 15.63 and 17.5 kcal/mol, respectively. Notably, the product oxides formed in the two cases are different. With air, the reaction is fast and the final product is Fe₂O₃, whereas with SO₂, the major product is Fe₃O₄, which slowly oxidizes to Fe₂O₃ in a secondary step. Also, in the latter reaction elemental sulfur is formed.