中低温煤焦油加氢精制催化剂的结构调控及加氢脱氮脱硫性能研究

It is significant to investigate the catalytic hydrogenation of medium and low-temperature coal tar for producing clean fuel. The key point of achieving the efficient denitrification and desulfurization process is to develop the hydrofining catalyst with high hydrodenitrification activity. The NiMo(W)/γ-Al2O3 catalysts prepared by traditional impregnation method have some problems, such as poor distribution of active components on the support surface, lower active sites density, difficult to mix well with coal tar, and a long start cycle caused by the presulfidation treatment in the reactor of oxidized catalysts. In our research, sulfided high loading NiMo-AlOOH slurry catalyst will be prepared with complete liquid-phase method.The hydroxyl-group-rich AlOOH carrier could offer substantial active metal adsorption sites. A uniform and high dispersion of active components on the support could be obtained by introducing Ni and Mo during the support synthesis process. Meanwhile the active site density of the catalyst could be enhanced. The active phase fine structure regulation will be investigated through precisely controlling the precursor preparation and heat treatment process. The influence of doping other components in situ on the catalyst acidity will be revealed. Moreover, the relationship between the catalyst acidity and active phase fine structure, and the catalytic behavior will be clarified. With the synergistic effect of acid center and metal center of the catalyst, the hydrodenitrification activity of the catalyst would increase, thereby promoting the deep removal of quinoline and dibenzothiophene. The results of this study will be conducive to provide scientific basis for the design and industrial application of high efficienct medium and low-temperature coal tar slurry bed hydrofining catalyst.

中低温煤焦油催化加氢制备清洁燃料油具有重要意义，开发具有高加氢脱氮活性的催化剂是实现其高效脱氮脱硫过程的关键。针对浸渍法制备的NiMo(W)/γ-Al2O3催化剂活性组分分散度低、活性位密度低、不易与煤焦油充分混合以及氧化态催化剂在反应器内预硫化导致开工周期长的难题，采用完全液相法制备浆状硫化型高负载量NiMo-AlOOH催化剂。富羟基的AlOOH做载体提供更多的活性金属吸附中心，在载体合成过程中原位引入Ni、Mo活性组分促进活性金属的均匀高度分散，并提升催化剂活性位密度。通过精细调变催化剂前驱体合成及热处理过程，实现活性相精细结构的调控。揭示掺杂组分对催化剂酸性的影响规律。阐明催化剂酸性和活性相精细结构与催化行为之间的关联。利用活性金属中心与载体酸中心的协同作用，提高催化剂加氢脱氮活性，促进喹啉和二苯并噻吩深度脱除，为高效中低温煤焦油浆态床加氢精制催化剂的设计和工业化应用提供科学依据。

从中低温煤焦油制取清洁燃料不仅能显著提高煤焦油资源的利用率，同时可有效补充紧张的石油资源供应。本项目设计合成具有高加氢脱氮活性的中低温煤焦油浆态床加氢催化剂。从催化剂构效关系研究及性能调控角度出发，围绕完全液相法制备浆状高负载量NiMoAl催化剂展开了一系列研究工作。探索了NiMoAl催化剂前驱体的合成，通过优化合成配方和调节醇铝水解来调控NiMoAl催化剂的织构性质和金属-载体间相互作用，活性金属通过与AlOOH上羟基作用锚定在载体表面，所获得NiMoAl催化剂的脱氮活性高于采用商业载体经浸渍法制备的NiMo/γ-Al2O3催化剂。热处理环境能改变活性相的结构，与空气中焙烧相比，采用液相热处理更有利于形成小晶粒(Ni)MoS2，从而提高活性金属分散度和催化剂的加氢脱氮性能。在催化剂前驱体合成过程中添加硼或硅组分，可使NiMoAl催化剂的酸分布和酸量发生显著变化，通过原位掺杂的方法调控NiMoAl催化剂的酸性质，同时提高了催化剂的加氢脱氮和加氢脱硫性能。总之，通过本项目的实施，探索研究了NiMoAl催化剂的完全液相制备，提高了活性金属分散性及Brønsted酸量，有效调控了活性金属中心与载体酸中心，从而提升了催化剂的反应性能，这为今后进一步开展高效浆态床加氢催化剂的研究提供了重要基础。