微介孔ZSM-5负载NiMo催化剂的三甲苯加氢脱烷基性能研究

以ZSM-5沸石及不同碱处理时间下制备的微介孔HZSM-5作为催化剂载体，采用等体积浸渍法制备了一系列NiMo/ZSM-5催化剂（分别记为NiMoPZ，NiMoAKZ-1，NiMoAKZ-2，NiMoAKZ-3）。采用X射线衍射、傅里叶变换红外光谱、N₂吸附-脱附、扫描电镜和热重分析对4种催化剂进行表征，并在反应温度410～530 ℃、反应压力1 MPa、质量空速2.4 h^-1、H₂/三甲苯体积比300的条件下分别对4种催化剂催化1,3,5-三甲苯(1,3,5-TMB)加氢脱烷基反应性能进行评价。结果表明：不同碱处理时间会改变催化剂的孔结构、酸性和形貌，并且影响催化剂的加氢脱烷基反应性能；碱处理时间为2 h时制备的NiMoAKZ-2催化剂具有较优的加氢脱烷基反应性能，在反应温度为530 ℃时，1,3,5-TMB转化率为91.5%，轻质芳烃（BTX）收率为65.3%，BTX选择性为71.3%；NiMoAKZ-2催化剂的介孔孔道提高了1,3,5-TMB与酸性位的可接近性，且其表面非骨架硅铝物种较少，孔道贯通性较好。

STUDY ON THE PERFORMANCE OF MICRO-MESOPOROUS ZSM-5 SUPPORTED NiMo CATALYST FOR HYDRODEALKYLATION OF TRIMETHYLBENZENE

A series of NiMo/ZSM-5 catalysts (designated as NiMoPZ, NiMoAKZ-1, NiMoAKZ-2, NiMoAKZ-3 respectively) were prepared by using ZSM-5 zeolite and micro-mesoporous HZSM-5 catalysts prepared under different alkali treatment time as the support. The catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N₂ adsorption desorption, scanning electron microscopy and thermogravimetric analysis. The hydrodealkylation performance of 4 catalysts were evaluated under the condition of a H₂ /1,3,5-trimethylbenzene (1,3,5-TMB) volume ratio of 300, a reaction temperature of 410-530℃, a reaction pressure of 1 MPa,a space velocity of 2.4 h^-1, respectively. The results showed that the pore structure, acidity and morphology of the catalysts were changed and the hydrodealkylation performance of the catalysts were affected by the alkali treatment time. The NiMoAKZ-2 catalyst prepared by alkali treatment for 2 h had excellent hydrodealkylation performance with the 1,3,5-TMB conversion of 91.5%, the BTX yield of 65.3%, and the BTX selectivity of 71.3% at the reaction temperature of 530℃. The accessibility of acidic sites by 1,3,5-TMB was improved by the mesoporous channel of NiMoAKZ-2 catalyst, and the surface of the catalyst had less non-framework Si-Al species, and the permeability of the channel was good.