满足国VI标准FCC汽油深度加氢脱硫-辛烷值恢复催化剂的设计、制备及其作用机制研究

The zeolite-based bifunctional catalysts with different intimacy (distance) between active sites for hydrogenation and acid catalysis will be designed and prepared by using hierarchical ZSM-5 from nanocrystal aggregation, alumina, and their composites as supports, respectively, and by changing the surface properties of supports and the structures of metal ions in solutions. The kinetic and mechanisms of the alkene aromatization, skeletal isomerization and cracking reactions will be studied over ZSM-5 zeolite. The roles of pore structure and acidic properties will be discussed to clarify the optimal hierarchical ZSM-5 zeolites for the selective conversion of alkene to aromatics and isomerization products with a high octane number. The intrinsic kinetic study of benzothiophene hydrodesulfurization and alkane hydroisomerization, together with the product distributions of the coupled deep hydrodesulfurization and octane number recovery (aromatization and hydroisomerization) of FCC gasoline over bifunctional catalysts, will be carried to study the relation for the intimacy between hydrogenation sites (transitional metal sulfide) and acid sites and the catalytic performance (activity, selectivity and stability). These will be useful to clarify the synergy mechanism between the active sites for hydrogenation and acid catalysis, and enhance the development of highly efficient catalysts for the coupled deep hydrodesulfurization and octane number recovery of FCC gasoline as well as the method for the preparation of catalysts. The as-prepared bifunctional catalysts will be tested in the coupled deep hydrodesulfurization and octane number recovery of China VI FCC gasoline under the reaction conditions applicable for the DSO technology by using FCC heavy gasoline as raw materials. These results will give useful information to optimize the design and synthesis of bifunctional catalysts.

采用具有多级孔结构的纳米晶堆积ZSM-5沸石、氧化铝及其与分子筛复合物为载体，改变载体表面性质和金属盐溶液中金属离子结构，设计并制备不同加氢活性中心和酸中心亲密度（距离）的沸石基双功能催化剂。通过研究反应动力学和机理，探讨ZSM-5沸石孔结构和酸性质对烯烃芳构化、骨架异构化和裂化的影响规律，筛选并优化适合烯烃转化制高辛烷值芳烃和异构烃的ZSM-5沸石。通过苯并噻吩加氢脱硫和烷烃加氢异构本征动力学研究，结合FCC汽油加氢脱硫-辛烷值恢复（芳构化和加氢异构化）反应产物分布，探讨加氢中心（过渡金属硫化物）与酸中心亲密性与反应性能（活性、选择性和稳定性）的构效关系，阐明酸中心和加氢中心的协同作用机制，开发高效FCC汽油深度加氢脱硫-辛烷值恢复催化剂及其制备方法。结合DSO技术，以FCC重汽油为原料，考察双功能催化剂通过深度加氢脱硫-辛烷值恢复生产满足国VI标准FCC汽油的性能，完善催化剂设计与制备

日益严格的环境保护法规使清洁汽油的生产成为我国炼油工业一个重要的挑战。降低汽油烯烃含量，同时保持辛烷值标是我国FCC汽油质量升级生产国VI清洁汽油面临的技术难题。开发能够将烯烃选择性转化为高辛烷值异构烷烃和芳烃的催化材料和催化剂是解决问题的关键。项目系统研究了沸石分子筛的拓扑结构和酸性质与烯烃择形转化的构效关系，进而确定烯烃选择性转化的沸石分子筛类型。结合实际需求，项目围绕ZSM-5沸石，开发了一种低成本、无须介孔模板剂直接合成多级结构的纳米晶堆积ZSM-5沸石的方法，并通过反应条件优化实现沸石酸性质和晶粒尺寸的控制制备，验证了硅源解聚与原位晶化同步的多级结构沸石分子筛合成策略，为沸石分子筛的合成机制研究提供重要证据。项目阐明了ZSM-5沸石晶粒尺寸与酸性质之间的构效关系，并发现该关系对于涉及烯烃转化反应中催化剂的稳定性存在制约作用，为设计和开发高效的烯烃转化沸石分子筛提供了理论依据。在此基础上，项目研究了多级结构ZSM-5沸石催化1-辛烯芳构化和1-己烯临氢异构化，金属磷化物催化苯并噻吩加氢脱硫等反应历程，结合FCC汽油的降烯烃评价反应，探讨了基于ZSM-5沸石的双功能催化剂催化烯烃择向芳构化和异构化的反应规律和双功能催化剂的作用机制。研究发现，原位水热金属改性沸石分子筛，能够促进改性金属在沸石孔内的分散，进而可以选择性调变沸石分子筛的酸性质。这为开发不同烯烃转化途径的汽油降烯烃催化剂提供理论和实验支持。以生产满足国VI清洁汽油为目标，以FCC汽油为原料，项目考察沸石基双功能催化剂催化汽油降烯烃和辛烷值恢反应结果，优化降烯烃催化剂制备方法，并实现催化剂的中试放大生产。