多级孔材料可控合成及其加氢改质反应性能的构效关系研究

Stringent regulations of environmental protection laws and regulations impel the publication of strict fuel specifications. The production of ultra clean fuels will be an important task in the future. Besides the removal of the refractory large molecular sulfur compounds from gasoline and diesel, it is necessary to solve the problems derived from the low octane number and high solidifying point of n-alkane. In order to achieve the goals of ultra-deep desulfurization, hydrodewaxing and octane number preservation, this proposal focuses on the directional synthesis of novel hierarchical porous materials and catalysts, which possess the dual functions of HDS and ISO. Using microporous molecular sieve with different topological structures as the precursor, the ordered meso-microporous composites with different acidities and pore sizes were synthesized by in-situ self-assembly method. Furthermore, the systematic researches of the adsorption, diffusion, and the reactions of typical model compounds (sulfur compounds, n-hexane, dodecane and tetradecane) will be investigated over the hierarchical molecular sieves catalysts with different pore structures and different acidities. The relationship between the structure characteristics, physico-chemical properties, the “limit effect” of the active phases and the performance of catalysts will be further studied. The reaction mechanisms of HDS and ISO will also be studied in details by integrating the DFT calculations with special analytical techniques of GC-MS, In-situ IR, Raman, EXAFS, and XANES, etc. This project will lay a firm theoretical and experimental foundation for the practical production of ultra clean fuel oil.

严格的环保法规推动超清洁油品生产进程。针对油品中大分子硫化物难以脱除，及正构烷烃辛烷值小、凝点高的问题，为实现深度脱硫、降凝和提高辛烷值的目标，本申请拟设计合成具有HDS及异构双功能的新型多级孔复合材料催化剂。采用酸性适宜、异构化性能良好的不同拓扑结构微孔分子筛为前驱体，原位自组装合成不同孔道结构的介孔材料，形成有序介微孔复合材料，实现不同酸性、拓扑结构、孔道尺寸多级孔分子筛的可控制备。进而采用动力学方法，考察模型化合物分子（硫化物、正己烷、正十二烷和正十四烷）在不同酸性、孔道结构的多级孔材料负载型催化剂中的扩散及反应规律，深入研究和探讨材料结构物性、活性相“限域效应”与催化剂反应性能之间的相互关系。结合GC-MS、In-situ IR、Raman、EXAFS、XANES等分析技术与密度泛函理论（DFT）计算，分析研究加氢脱硫和异构化的反应机理，为实现超清洁燃油生产奠定理论研究和实验基础。

超清洁油品的生产对于环境保护及社会经济可持续发展具有深远的意义，新型高活性加氢脱硫催化剂的研发是技术升级的关键。本研究针对难脱除硫化物分子尺寸大、存在烷基位阻的特点，定向设计合成酸性适宜、具有多级孔道结构的Beta-SBA-16、ZSM-5-SBA-16、Beta-FDU-12以及ZSM-5-FDU-12复合材料，通过优化调变催化剂孔道结构、酸性及理化性质实现催化剂高加氢脱硫活性。同时，通过加氢反应中间及最终产物分析，结合GC-MS等表征方法细致研究了复合孔材料催化剂的加氢深度脱硫反应机理和规律。基于实验结果，开展了密度泛函理论计算，系统研究了不同反应条件下MoS2基活性相表面硫空位的形成机制。基于实验以及理论两方面相结合，为实现超清洁油品加氢精制催化剂的结构优化及升级换代提供了科学研究基础和指导。