哌啶对负载型Pt催化剂加氢脱硫性能的影响

将ZSM-5溶于偏硅酸钠水溶液,用水热合成法以十六烷基三甲基溴化铵作模板剂自组装合成了ZSM-5/MCM-41介孔硅铝分子筛(ZM)。以二苯并噻吩(DBT)和哌啶作为模型含硫和含氮化合物,考察了含氮化合物对ZM担载的Pt催化剂加氢脱硫(HDS)反应性能的影响。结果表明,DBT在Pt/ZM催化剂上主要通过直接脱硫(DDS)反应路径脱硫,引入哌啶显著抑制了DBT的HDS反应。与DDS相比,哌啶对加氢路径(HYD)抑制作用更强,并且几乎完全抑制了HYD路径含硫中间体的脱硫。动力学分析表明,DBT的HDS反应和DDS路径级数为一级而其HYD路径则为零级,说明DDS和HYD反应可能是在Pt/ZM不同活性中心上进行的。

Influence of Piperidine on the Hydrodesulfurization Performance of the Supported Pt Catalyst

ZSM-5/MCM-41 mesoporous aluminosilicate molecular sieve(ZM) was hydrothermally synthesized by assembling zeolite subunits,which were generated from the hydrolysis of ZSM-5 in a Na2SiO3 aqueous solution,in the presence of cetyltrimethylammonium bromide as the template.The influence of the nitrogen-containing compound on the hydrodesulfurization performance of Pt carried by ZM was studied by using dibenzothiophene(DBT) and piperidine(Pi) as the model molecules.The results indicate that DBT HDS over Pt/ZM predominately takes the route of direct desulfurization(DDS).The addition of Pi strongly has inhibited the HDS of DBT.Compared with the DDS pathway,Pi shows stronger inhibition effect on the hydrogenation pathway(HYD),and the desulfurization of the sulfur-containing intermediates of the HYD pathway is almost completely suppressed by Pi.The kinetic study reveals that the HDS of DBT and the DDS pathway are first order while the HYD pathway is zero order under the conditions studied,suggesting that the DDS and HYD reactions may have taken place on different active sites of Pt/ZM.