以硫代硫酸铵为硫化剂对MoO3/Al2O3催化剂进行预硫化,考察了制备方法和活化条件对预硫化催化剂噻吩加氢脱硫活性的影响.结果表明,硫代硫酸铵预硫化的催化剂活化后,加氢脱硫活性好,噻吩的转化率达到99%以上,而二甲基二硫硫化的MoO3/Al2O3催化剂在相同条件下,噻吩转化率只有92%.合适的活化温度为200~300℃,活化压力增加有利于预硫化催化剂的还原硫化和加氢脱硫活性的提高.硫代硫酸铵预硫化催化剂的高脱硫活性主要归因于多层的Ⅱ型MoS2活性相的形成,其次是硫化程度的提高.硫代硫酸铵预硫化催化剂经过氢气活化和补充硫化两个阶段,其硫化程度高于传统方法硫化的催化剂.
MoO3/Al2O3 catalyst has been presulfided by ammonium thiosulfate. The effects of the presulfidation methods and the activation conditions on the hydrodesulfurization of thiophene were investigated. The results showed that the catalyst presulfided by ammonium thiosulfate (designated as Mo-ATS) exhibited higher activity than the one presulfided by dimethyldisulfide (denoted as Mo-DMDS). The former method gave a conversion of more than 99 % in contrast to 92 % obtained by the latter one under the same reaction conditions. The optimum temperature for the catalyst activation was in the range of 200-300℃. An increase in the pressure was favorable for the activation and the enhancement in the HDS activity. In comparison to Mo-DMDS, the higher activity of Mo-ATS than that of Mo-DMDS was mainly attributed to the formation of an active type 11 MoS2 phase as a result of suppressing the interaction of Mo with γ-Al2O3 by modifying its surface with sulfate species. In addition, an increase in sulfidation degree (S2-/Mo molar ratio) was observed after activation and supplemental sulfidation. This is also favorable for hydrodesulfurization.