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1、北京服装学院硕士论文 摘 要 摘 要 以炼厂丙烯为原料固定床液相法合成异丙苯反应过程中，微量杂质的存在和反应历程的复杂性使催化剂很快失活炼厂丙烯中含有少量高度不饱和烃，如丁二烯，丙炔，丙二烯，丁烯，它们极易在沸石催化剂表面生成积炭前身物，造成催化剂的结焦失活为了除去炼厂丙烯中含有的杂质可以采用选择加氢的方法，使其转化为单烯烃或饱和烃。为此通过沸石催化剂进行改性, 将钯负载在 FX-01 催化剂上，不但使其具有烷基化的催化作用，还具有选择加氢的作用。本文考察了负载金属钯改性制得的双功能催化剂，在加速失活条件下，对于催化剂的活性、选择性和稳定性的响 钯是贵金属，负载的金属含量在提高催化剂的稳定性的
2、，同时应尽可能的减少其用量，提高贵金属的利用效率经过考察不同负载量对于催化剂的活性，选择性和稳定性的影响，综合考虑，以离子交换制得负载金属钯千分之二的催化剂为最优. 利用色质联用仪和氧化烧碳分析了改性前后催化剂上积碳组成的变化，结果表明催化剂改性确实提高了催化剂的稳定性同时，对本实验条件下忽略内外扩散的影响，即在内动力学区进行反应时，进行了模拟.经过模拟本征动力学条件下反应，可以很容易考察反应过程的工艺参数对催化过程的影响，并对工艺参数进行优化，但活塞流反应器只是理想反应器理想化的假设和和对于反应器的动态行为难以考察使得模拟结果有一定的局限性尽管如此，对于实验仍有很好的参考作用，并指明了研究的
3、方向模拟结果表明实验中应严格控制苯烯比，才能在指定的温度下确保反应在液相区进行，减少新相出现的可能性，便于利用液相法传热，传质效率高，生产能力大的优点同时，严格控制反应温度，尽量在最佳反应温度下进行，提高目的产物的收率 关键词 沸石;分子筛;改性;载钯;失活;寿命;烷基化;模拟 I 北京服装学院硕士论文 Study on the Deactivation and Modification of the Catalyst in Liquid Phase Alkylation of Benzene and Propylene A b s t r a c tA b s t r a c t Catal
4、yst employed in the production of cumene with benzene and propylene from the refinery is fairly prone to deactivate in the presence of the impurities in small amounts, or as a consequence of the complexity of the reaction mechanism .Such unsaturated hydrocarbon as 1,3-butadiene,allylene, propadiene
5、,which has larger propensity than propylene to deposit on the surface of the catalyst leading to the formation of the precursor of the coke and rapid deactivation of the catalyst. To eliminate small amounts of the impurities present in the propylene from the refinery, the hydrogenation treatment is
6、usually performed for the purpose of transforming them into monoene, or to the extent of saturated hydrocarbon. For the same reason, the incorporation of Palladium on the catalyst are supposed to make it be capable of alkylation and selective hydrogenation. The evolvement of modified bifunctional ca
7、talyst by supporting Palladium on it with respect to the reactivity, selectivity and stability is investigated by accelerated decay. As a kind of noble metal, it makes much difference in economic sense in spite of the fact that it greatly enhances the stability. .Meanwhile, it is of great importance
8、 to reduce the consumption of supported Palladium and increase the efficiency of it. After investigation of influence of different amounts of the supported Palladium on the reactivity, selectivity and stability, the catalyst with 0.2wt% Palladium is much preferable from the overall viewpoint. The ch
9、ange in the composition of the coke deposited on the surface of the catalyst is analyzed by GC-MS and oxidation coke burning. It may safely be concluded that the catalyst prepared in our lab does exhibit higher stability .At the same time, a simulation of theprocess is conducted under the experiment
10、al conditions with the intrinsic rate equation without taking into account the effect of the internal and external diffusion, in other words the reaction proceeds in the range of internal dynamics. By carrying out the simulation, it is fairly easy to evaluate the influence of the process parameters
11、on the reaction, and optimize their values. But the piston flow reactor is an idealized hypothesis and the difficulty to assess the dynamic behavior result in the limitation. With that in mind , the simulation can serve as a satisfying reference which throw light on the direction II 北京服装学院硕士论文 of fu
12、rther study. As it shows in the simulation, the ratio of the benzene to propylene should be strictly manipulated to ensure the reaction occurs in the liquid phase and reduce the tendency of formation of a new phase, so the advantages of the liquid phase method ,which is assumed to greatly facilitate
13、 the heat and mass exchanging and increase the productivity. In the meanwhile, it is of great importance to keep a close control of the temperature to increase the yield of the preferred product at the optimized temperature。 Keywords zeolite catalyst ; molecular sieve; modification; supported Pallad
14、ium; lifetime; deactivation; lifetime; alkylation; simulation III 北京服装学院硕士论文 目 录 0 前 言. 1 1.文献综述 . 2 1.1 异丙苯的生产历史与现状. 2 1.2 异丙苯的合成及反应机理. 2 1.2.1 异丙苯的合成. 2 1.2.2 苯与丙烯烷基化反应机理. 3 1.3沸石分子筛的特点及应用 . 6 1.3.1 沸石分子筛的结构 . 6 1.3.2沸石分子筛的改性 . 7 1.4 沸石催化剂失活机理. 9 1.4.1 反应物对积碳的影响. 11 1.4.2 操作条件对积碳的影响. 11 1.4.3 酸性质对积碳的影响. 11 1.4.4 空速的影响. 12 1.4.5
