将我国高产量的煤焦油加工利用可以缓解能源紧张问题,煤焦油加氢脱氮是煤焦油清洁高效利用的重要手段,而此过程的关键在于高性能加氢脱氮催化剂的制备。针对普通的Al2O3易与负载的活性金属存在强相互作用而影响加氢性能的问题,基于二维载体特殊的表面性能和层状结构,以氧化石墨烯为结构导向剂,TiO2为改性剂,对Al2O3进行改性,制备了一种新型片层TiO2−Al2O3复合载体材料。并采用共浸渍法在其上负载活性金属,制备了系列NiMoS/TiO2−Al2O3催化剂。试验通过制备不同维数的载体材料,探究了载体的结构对相应NiMoS催化剂加氢脱氮催化活性的影响。结果表明,反应温度350℃,反应釜中压力3MPa,反应4h时,相比于三维负载型催化剂,二维负载型NiMoS/TiO2−Al2O3催化剂能够使喹啉的转化率由94.2%提升至99.4%,脱氮率由0.6%提升至74.8%,其中丙基环己烷和丙苯的收率分别为58.4%和13.4%,说明二维负载型NiMoS/TiO2−Al2O3催化剂具有较好的加氢脱氮性能。进一步分析载体及改性后催化剂的几何结构发现,二维TiO2−Al2O3载体存在多孔的片层结构,Lewis酸比例高,有利于1,2,3,4-四氢喹啉的进一步加氢和十氢喹啉的开环,从而生成脱氮产物丙基环己烷。NiMoS催化剂的比表面积大,MoS2在载体表面的分散度高,团簇颗粒小,金属−载体间相互作用较弱,易被还原硫化生成更多的NiMoS活性相,因而具备了更优的催化加氢脱氮性能。

Processing and utilization of high-yield coal tar in China can alleviate the energy shortage. Hydrodenitrogenation (HDN) ofcoal tar is a significant way to utilize coal tar in a clean and efficient manner,and the key is the preparation of high performance HDNcatalyst. There is a strong interaction between traditional Al2O3 and supported active metals,which affects the hydrogenationperformance. Based on the special surface properties and layered structure of the two-dimensional support,a novel support material wasprepared by modifying Al2O3 with graphene oxide as structure director and TiO2 as the modifier. A set of NiMoS/TiO2−Al2O3 catalystswere prepared by impregnation process and used in the quinoline HDN reaction. The effects of carrier dimensions on the structure ofsupport and the catalytic performance of NiMoS catalysts for HDN were investigated. When HDN reaction was performed at 350 ℃ and3MPa (H2) for 4h,compared with those of three-dimensional supported catalysts,the conversion rate of quinoline increased from94.2% to 99.4%. The nitrogen removal efficiency of quinoline increased from 0.6% to 74.8%,the yields of propylcyclohexane andpropylbenzene were 58.4% and 13.4%,respectively. The results indicate that the supported two-dimensional NiMoS/TiO2−Al2O3 catalyst possesses better HDN performance. The geometrical structure of support and modified catalyst was further analyzed. It is found that two-dimensional TiO2−Al2O3 carrier exists porous lamellar structure,high proportion of Lewis acid,which is conducive to furtherhydrogenation of 1,2,3,4-tetrahydroquinoline and open-loop of decahydroquinoline. Thereby the denitrogenation product,propylcyclohexane is generated. The NiMoS catalyst supported by two-dimensional TiO2−Al2O3 exists large specific surface area,highdispersion of MoS2 on the carrier surface,small cluster parti cles,weak metal-support interaction. And it is easily sulfurized to generatemore active NiMoS phases,so it displays better catalytic HDN performance compared with the NiMoS catalyst supported by three-dimensional TiO2−Al2O3.