Temperature-Programmed Surface Reaction Study of Adsorption and Reaction of H2S on Ceria

H2S adsorption and reaction on CeO2, TiO2, and ?-Al2O3 were studied by temperature programmed surface reaction (TPSR). Ceria had the best desulfidation ability. The pretreatment atmosphere affected H2S adsorption and reaction on ceria, and desulfidation efficiency increased in the order of inert atmosphere, reducing atmosphere, oxidizing atmosphere. H2S was first adsorbed on pretreated ceria at room temperature. On increasing the temperature in an Ar (99.99%) atmosphere, part of the H2S desorbed below 673 K, and another part reacted with the surface oxygen on ceria to produce sulfur and water below 473 K, and SO2 between 473 and 673 K, which further reacted with lattice oxygen and was transformed into sulfate above 673 K. The sulfate decomposed into SO2 again at 873 K. To avoid the complex regeneration, it is advisable to carry out desulfidation below 673 K when using ceria as adsorbent.

摘要采用程序升温表面反应技术研究了 H2S 在 CeO2, TiO2 和 Al2O3 三种载体上的吸附和反应行为. 结果表明, CeO2 具有最强的脱硫能力. 系统研究了预处理气氛对 H2S 在 CeO2 上吸附和反应行为. 发现 CeO2 的脱硫能力在惰性气氛 还原性气氛 氧化性气氛中依次增强. H2S 首先吸附在经预处理的 CeO2 表面, 进一步在 Ar 氛围下升温脱附时, 一部分 H2S 在 673 K 以下脱附, 部分则与 CeO2 表面氧反应, 在 473 K 下产生硫和水, 而在 473∼673 K 温度范围内, 生成 SO2. 在 673 K 以上, 所生成的 SO2 进一步与晶格氧反应, 转化成硫酸盐. 后者在 873 K 再次分解为 SO2. 因此, CeO2 表面脱硫过程应控制在 673 K 以下, 可避免复杂的再生过程. 

Some adsorbed H2S desorbed below 673 K, sulfur and water were formed below 473 K, SO2 was formed from 473 to 673 K, and sulfate was formed above 673 K when H2S was adsorbed on ceria.Figure optionsDownload as PowerPoint slide