【作者】 龙立华；

【导师】 伏再辉； 万焱波；

【作者基本信息】 湖南师范大学 ， 有机化学， 2004， 硕士

【摘要】 催化裂化是石油炼制工业的重要手段之一，它能提供柴油、汽油、液化石油汽，同时在催化裂化过程中产生的芳烃和低碳烃，特别是轻烯烃可作为化工的基础原料。为了满足产品需求多样化的要求，就必须开发“量体裁衣”催化剂。这样作为催化裂化剂活性组分的分子筛也就应该具备多元化的特性。同时基于催化裂化加工数量巨大，任何细微的改进都可能带来显著的经济效益。本文的研究就是基于这点出发，在考查ZSM-5分子筛催化裂化反应性能的基础上，通过浸渍法和离子交换法，分别引入了磷、钛、锌等对其进行改性。同时也用磷对ReY型分子筛进行改性处理。改性的分子筛分别用静态低温氮吸附法、XRD、SEM以及DTA等手段进行了表征，其催化裂化反应性能用重油微反装置或者小型固定流化床进行了评价。 研究发现：（1）在催化裂化条件下，ZSM-5分子筛的硅铝比在50～100以内有较好的活性；（2）磷对ZSM-5分子筛的改性使分子筛的孔道结构、比表面和晶体形貌都发生较大的变化，使分子筛酸中心性质更为合理，从而显著提高了分子筛的活性和稳定性，并改善了特定产物的选择性，诸如能够大幅度提高液化石油气和丙烯、丁烯产率，能有效地降低汽油烯烃含量，提高汽油辛烷值；（3）磷和稀土对Y型分子筛有协同改性的作用，磷可以进一步调变了ReY酸中心性质，从而提高了分子筛的催化裂化活性和氢转移能力，有效地降低了汽油中烯烃的含量。但P₂O₅含量应控制在1.0％～2.5％为宜，过高的磷含量反而会削弱分子筛的催化裂化性能；（4）钛对ZSM-5分子筛改性使其孔结构发生一定的变化，孔容（PV）在一定钛含量范围时反而还有所增加。钛改性能使催化裂化汽油烯烃含量下降，但其焦炭产率却明显增加。（5）锌改性ZSM一5分子筛随着锌含量的增加其比表面和孔容均呈下降趋势，能使催化汽油中的烯烃含量有所减少，但焦炭产率和氢气产率明显增加。 山于不同元素改性后分子筛在催化裂化条件下呈现出不同的反应性能，因此，木文的研究结果可以为催化裂化开发多元化的催化剂提供一些基础依据，同时也为进一步的研究提供了一些有意义的信息。更多还原

【Abstract】 Catalytic cracking is one of very important processes of petroleum refining,because many kinds of chemicals come from it. And catalytic cracking catalyst play a key role in catalytic cracking or FCC(Fluid Catalytic Cracking). So it is necessary to develop various modified zeolites, which are main components of catalyst, in order to meet the need of diversification. And any insignificant enhancement will bring out significant profits, owing the enormous amount of process.In this dissertation, The ZSM-5 zeolites modified by phosphorus , titanium, zinc respectively, and the ReY zeolite modified by phosphorus were prepared through ion-exchange or impregnant and then being calcined by high temperature steam. The above modified zeolites’ relative crystallinity, unit cell parameters, BET surface area , pore structure, collapse temperature were measured by XRD, static nitrogen volumetric adsorption method under low temperature, DTA. And their feature were observed by SEM. The catalytic performances of the modified zeolites were evaluated by heavy oil fixed bed microreactor or fluid bed microreactor.It was discovered that : (1) the ZSM-5 zeolite with lower ratio of Si to Al has better catalytic cracking performances; (2) The physiochemical properties and catalytic performances of the phosphorus-containing ZSM-5 zeolite were greatly improved, especially its activity and selectivity to propylene were drastically enhanced; (3) the titanium-containing and zinc-containing ZSM-5 zeolites can decrease the content of olefin and increase the content of the aroma to some extent in gasoline, while the selectivity to coke will become bad. But there are some differences between them; (4) the ReY modified by phosphorus has higher activity and hydrogentransfer ability, therefore it can decrease the content of olefin in gasoline and has good selectivity to coke during the course of catalytic cracking process.The above results are very useful to develop some novel catalysts.更多还原