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为了筛选适用于异构化 /吸附分离工艺的催化剂 ,考虑到ZSM -5分子筛对直链烷烃的择形催化作用 ,以其为载体 ,采用离子交换法对其改性 ,并负载了不同含量的贵金属Pd。在此基础上 ,利用微反 -色谱系统考察了不同Pd负载量、氢压和反应温度对HZSM -5催化剂异构化活性的影响以及Pd对该类催化剂异构化选择性和稳定性的影响。结果发现 ,HZSM -5催化剂负载Pd后可以有效地提高反应的稳定性及异构化选择性 ;金属分散度的提高有利于改善催化剂的异构化选择性 ;反应温度过高将导致金属的加氢裂化活性增强 ,使异构化选择性下降 ,因此以中温 2 50℃为好 ;在中温下操作时 ,为保证一定的异构化活性 ,氢压不宜太大 ,应控制在 1 .5MPa左右。
In order to screen the catalysts suitable for the isomerization / adsorption separation process, taking into account the shape-selective catalytic action of ZSM-5 molecular sieve on linear paraffin, it was modified by ion exchange method and loaded with different contents of Precious metal Pd. On this basis, the influence of Pd loading, hydrogen pressure and reaction temperature on the isomerization activity of HZSM -5 catalyst and the effect of Pd on the isomerization selectivity and stability of these catalysts were investigated by using micro-reversed-phase chromatography . The results showed that HZSM-5 catalyst can effectively increase the stability and isomerization selectivity of Pd supported Pd catalyst. The improvement of metal dispersion can improve the isomerization selectivity of the catalyst. When the reaction temperature is too high, Hydrocracking activity increases, so that the selectivity of isomerization decreased, so the temperature of 50 ° C is better; at moderate temperature operation, in order to ensure a certain degree of isomerization activity, hydrogen pressure should not be too large, should be controlled at about 1. 5MPa .