焦化粗苯同时脱硫脱氮新型MxP/复合分子筛催化剂的合成制备及反应机理研究

In present, the large amounts of by-product crude benzol in China’s coking industry is difficult to purify under low energy consumption. Thus, the study of crude benzol simultaneous hydrodenitrogenation and hydrodesulfurization to produce high value-added BTX has vital significance to protect environment, improve energy efficiency, and solve the shortage of BTX resources. This project plans to use micro-mesoporous composite molecular sieves prepared via the self-assembly strategy as the carrier，phosphorus species as the active sites， design a new crude benzene simultaneous hydrodenitrogenation and hydrodesulfurization catalyst. The main research contents are as follows: To study the effect of carrier on catalytic active sites by controlling the structure and properties of composite molecular sieves. The scientific catalyst preparation technology is studied by optimizing the preparation process and expanding the preparation methods of highly dispersed and nano-scale active sites. On this basis，a variety of techniques will be adopted to characterize the catalysts structure and track the surface reaction process. We will elucidate the catalyst active sites，physicochemical property and catalytic performance relationships at a molecular level and the reasons for catalyst deactivation. The reaction mechanism will be proposed using the removal of BT and Py as the probe reaction. More significantly，this study will provide a new insight for constructing other high-performance catalysts and a theoretical basis for the development of new technology.

针对我国焦化行业副产大量粗苯难以低能耗提纯的现状，开展粗苯同时脱硫氮制备高附加值BTX关键技术研究，对于我国保护环境、提高能源利用率、解决三苯资源短缺等有重要的意义。本项目拟以基于自组装原理制备的微介孔复合分子筛为载体，引入磷化物作为活性组分，设计合成一种新型粗苯同时脱硫脱氮精制催化剂。其主要研究内容为：通过对复合分子筛结构和性能的调控，研究载体与催化活性中心结构和性质的调变规律；考察并优化制备工艺，拓展高分散和纳米尺度活性位的构筑和制备方法，研究催化剂的制备科学和功能化制备技术；结合多种分析技术研究催化活性中心结构及其与反应物种的作用机制，从分子水平上揭示催化剂活性中心、物化性能与催化性能之间的构效关系及失活机制，以噻吩、吡啶等的脱除为探针反应研究反应机理，建立相应的反应模型，为高性能催化剂的设计制备以及新工艺技术的开发提供理论依据。

随着环保法规的日益严苛，高品质三苯资源的短缺，以及我国焦化行业副产大量粗苯难以低能耗提纯的现状，开展高活性、高选择性的新一代加氢精制催化剂研究，对于我国保护环境、提高能源利用率等有重要的意义。本项目以微介孔分子筛-氧化铝为复合为载体，引入磷化物作为活性组分，采用低温还原法制备了负载型磷化镍加氢精制催化剂。其主要研究内容为：采用水热合成法制备了微介孔复合分子筛，与氧化铝结合制备分子筛改性的复合载体，通过对分子筛的结构和性能的调控，研究复合载体对催化性能及物化性质的调变规律；采用浸渍-还原法制备了分子筛-氧化铝负载的磷化镍催化剂，考察并优化了催化剂制备工艺及反应条件，研究催化剂制备过程中磷镍比、负载量、干燥、还原温度、空速、氢气分压等对催化性能的影响，活性组分负载量为20wt%，反应温度330℃，空速4h-1，氢气分压 3MPa，氢油比500，在此条件下加氢脱硫转化率达到 97.4%，加氢脱氮转化率达到94.2%；结合多种分析技术研究催化剂的结构及其催化作用机制，进而研究了催化剂活性中心、物化性能与催化性能之间的构效关系，以二苯并噻吩、吡啶等的脱除为探针反应研究了脱硫氮反应机理，二苯并噻吩在磷化物催化剂上加氢脱硫反应主要经历碳-硫键断裂的直接脱硫反应途径。上述研究为高性能催化剂的设计制备以及新工艺技术的开发提供理论依据。