Abstract
A carbonyl sulfide (COS) hydrolysis catalyst can play an efficient role in blast furnace gas (BFG), but the life of the catalyst is greatly shortened due to the presence of O(2) and H(2)S in the atmosphere, so improving the sulfur resistance of the catalyst is the key to application. In this work, alkali metals Na and K modified γ-Al(2)O(3) catalysts to improve COS hydrolysis efficiency and sulfur resistance by adding an alkaline center. Compared with γ-Al(2)O(3) catalysts, the COS hydrolysis efficiency of the modified catalysts in the experiment was improved by 12% in the presence of H(2)S and O(2). The main cause of catalyst sulfur poisoning is the presence of O(2), which intensifies both the total amount of sulfur deposition and the proportion of sulfate. It is found that the NaOH/Al(2)O(3) catalyst shows better sulfur resistance than the KOH/Al(2)O(3) catalyst for two reasons: first, the support of Na can significantly improve the medium-strong alkaline site, which is the adsorption site of H(2)S. This is equivalent to increasing the "sulfur capacity" of H(2)S adsorption and reducing the impact of sulfur deposition on the main reaction. Second, the elemental sulfur is more easily produced on the NaOH/Al(2)O(3) catalyst, but the sulfur is further oxidized to sulfate and sulfite on the KOH/Al(2)O(3) catalyst. The molecular diameter of elemental sulfur is smaller than that of sulfate. Therefore, the NaOH/Al(2)O(3) catalyst has better sulfur resistance.