氨基三乙酸对Ni-Mo/Al_2O_3催化裂化柴油加氢脱硫脱氮活性的影响

EFFECT OF NITRILOTRIACETIC ACID ON HDS AND HDN ACTIVITY OF Ni-Mo/Al_2O_3 FOR FCC DIESEL

以等体积浸渍法制备Ni-Mo/Al_2O_3催化裂化柴油加氢处理催化剂,在金属浸渍液配置过程中引入一定比例的络合剂氨基三乙酸（NTA）制备改性催化剂Ni-Mo-NTA/Al_2O_3,通过改性前后催化剂的对比分析研究氨基三乙酸对催化剂加氢脱硫和脱氮活性的影响。采用100 mL高压加氢反应装置对催化剂进行加氢脱硫、脱氮反应活性评价,并以NH_3-TPD,H_2-TPR,BET,HRTEM等手段对催化剂进行表征。结果表明,引入氨基三乙酸后催化剂在不同反应温度等级下加氢脱硫和脱氮活性均有提高,这是由于氨基三乙酸改性后催化剂表面酸量提高,载体与金属作用力削弱,金属还原度提高,孔结构得到改善,MoS_2金属堆垛层数集中在2~3层,片晶长度集中在2~4 nm,金属分散度提高。

Ni-Mo/Al_2O_3catalyst for catalytic diesel hydrotreating was prepared by incipient wetness impregnation method. The modified Ni-Mo-NTA/Al_2O_3catalyst was made by adding nitrilotriacetic acid（ NTA） in impregnation solution. The effects of complex agent NTA on HDS and HDN activities were evaluated in a 100 m L high pressure fixed-bed reactor,and the physical and chemical properties were investigated by NH_3-TPD,H_2-TPR,BET and HRTEM techniques. The results indicate that Ni-Mo-NTA/Al_2O_3 catalyst has a higher HDS and HDN activity than Ni-Mo/Al_2O_3. The modification of Ni-Mo/Al_2O_3with NTA improves the surface acidity of the catalyst,reduces the interaction between active metals and support,increases the reducibility of metals,and optimizes the pore structure. The stack layer number of MoS_2 on the modified catalyst is 2—3 with a length of MoS_2 lamella of 2—4 nm,indicating the better dispersion of the active phases.