Reaction and Separation Mechanism in Zeolite Catalytic Membrane Reactor for Dehydrogenation

采用水热合成法在多孔α-Al 2 O3载体管上制备了FAU型分子筛膜。对膜进行了蒸汽渗透试验。在此基础上，在沸石膜反应器中进行环己烷脱氢反应。最后，对膜反应器中的反应和分离行为进行了模拟，并对苯和C4-C7饱和烃的气相渗透进行了研究。对于单组分进料的情况，环己烷的渗透率高于苯。同时，高的苯/环己烷选择性可归因于对苯的高吸附选择性和对环己烷的堵塞。对于苯和其他饱和烃二元混合物的情况也得到了类似的结果。在装有Pt/Al_2O_3催化剂的膜反应器中，使用FAU型分子筛膜对环己烷进行催化脱氢。采用等温操作和活塞流模式，建立了一个简单的数学模型，对FAU型分子筛膜反应器的性能进行了评价。模拟结果与实验结果吻合较好。结果，清楚地证明了膜反应器中催化剂上焦炭形成的减少。

An FAU-type zeolite membrane was formed on porous α-alumina support tube by hydrothermal synthesis method. Vapor permeation test of the membrane was carried out. Then dehydrogenation of cyclohexane was performed in the membrane reactor with the zeolite membrane. Finally, reaction and separation behaviors in the membrane reactor were simulated.Vapor permeation of benzene arid saturated C4-C7 hydrocarbons was studied. For the case of a single-component feed, permeance to cyclohexane was higher than that to benzene. Meanwhile high benzene/cyclohexane selectivity can be attributed to the high adsorption selectivity in favor of benzene and the blockage against cyclohexane. Similar results were obtained for the case of binary mixture of benzene and other saturated hydrocarbons.An FAU-type zeolite membrane was used for the catalytic dehydrogenation of cyclohexane in a membrane reactor packed with a Pt/Al_2O_3 catalyst. The conversion of cyclohexane in the membrane reactor increased beyond the thermodynamic equilibrium value due to the simultaneous removal of hydrogen and benzene from the reaction site.A simple mathematical model assuming isothermal operation and a plug flow pattern was developed to evaluate the performance of an FAU-type zeolite membrane reactor. The result of the simulation was in good agreement with the experimental result. As a result, the reduction in coke formation on the catalysts in the membrane reactor was clearly demonstrated.