ZSM-5/Beta多级复合分子筛的制备及其催化生物质热解制芳烃性能研究

Aiming at the key issues of low aromatics yield and high coke amounts in catalytic pyrolysis reaction and combining the excellent catalytic properties of composite molecular sieve, the investigations on the design, synthesis, and catalytic performance of composite molecular sieve with a core-shell structure and the mechanisms of melamine in the synthetic system will be carried out. Based on the melamine-assisted hydrothermal crystallization method, the simultaneous introduction of the mesoporous structure can be realized by adding the melamine in the gel system. The core molecular sieve was coated by a coating layer of the carbonaceous compound on the external surface. The coating layer has the functions of separating the core and shell of the core-shell molecular sieve and promoting the growth of shell molecular sieve on the external surface of core molecular sieve. The adjustment of ratios of nuclear (ZSM-5) and shell (Beta) layer, the controlling of style, intensity and density of acid sites and regulation the thickness of shell and the connectivity style between core and shell will be realized via optimization of the preparation conditions. Through the study of the effects of the pore structure and acidity of the composite molecular sieve on the fast pyrolysis of biomass to aromatics, the essential reason for improving the yield of aromatics by ZSM-5/Beta molecular sieve will be revealed. The above research aim is to provide the theoretical basis and technical support for the development of a new generation catalyst of fast pyrolysis of biomass.

针对现有生物质快速热解制芳烃催化体系中芳烃收率低和结焦量大的关键性制约问题，结合核-壳结构复合分子筛已展现出来的优异催化性能，本课题拟开展基于低廉生物质化合物（葡萄糖、蔗糖、三聚氰胺等）辅助的，兼具多级孔、多晶态、核壳结构ZSM-5/Beta多级复合分子筛的设计、制备、催化性能以及介孔造孔剂在合成体系中作用机制的研究。在核分子筛凝胶中加入介孔造孔剂共同水热晶化，实现在核分子筛中同步引入介孔的目的；在核分子筛表面包覆碳化合物层，包覆层具有将分子筛的核与壳分离，同时促使壳分子筛在核表面晶化的作用；通过制备工艺的研究，调变核（ZSM-5）、壳（Beta）层分子筛比例及酸中心类型、强度、密度，调节壳层分子筛厚度及核壳之间孔道连接方式，研究其对生物质快速催化热解制芳烃反应的影响规律，揭示ZSM-5/Beta多级复合分子筛提高芳烃产率的本质原因，为开发新一代生物质快速热解催化剂奠定理论和技术基础。

针对现有生物质快速热解制芳烃催化体系中芳烃收率低和结焦量大的关键性制约问题，结合核-壳结构复合分子筛已展现出来的优异催化性能，本课题拟开展基于低廉生物质化合物葡萄糖辅助的，兼具多级孔、多晶态、核壳结构ZSM-5/Beta多级复合分子筛的设计、制备、催化性能以及介孔造孔剂在合成体系中作用机制的研究。在核分子筛凝胶中加入介孔造孔剂共同水热晶化，实现在核分子筛中同步引入介孔的目的；在核分子筛表面包覆碳化合物层，包覆层具有将分子筛的核与壳分离，同时促使壳分子筛在核表面晶化的作用；通过制备工艺的研究，调变核（ZSM-5）、壳（Beta）层分子筛比例及酸中心类型、强度、密度，调节壳层分子筛厚度及核壳之间孔道连接方式，研究其对生物质快速催化热解制芳烃反应的影响规律，揭示ZSM-5/Beta多级复合分子筛提高芳烃产率的本质原因，为开发新一代生物质快速热解催化剂奠定理论和技术基础。