NiW/SAPO-11催化剂孔结构性质对其柴油异构降凝性能的影响

选用SAPO-11分子筛代替传统的ZSM-5分子筛作为酸性载体,Ni和W作为金属组分制备异构降凝催化剂。利用扩孔剂炭黑对催化剂进行扩孔处理,提高催化剂的传质性能,促进原料和产物分子的扩散。以长庆直馏柴油为原料,采用高压固定床微反装置,考察了扩孔剂含量对催化剂异构降凝催化性能的影响。结果表明,随着扩孔剂含量的增加,催化剂的孔容不断增大,大孔数量不断增多,其柴油异构降凝性能逐渐加强。其中, 7%C/NiW/SAPO-11催化剂的异构降凝催化性能最好,在反应温度340℃、反应压力4.0 MPa、空速1.0 h^-1、氢/油体积比500的条件下,凝点由0℃降至-11℃,柴油收率高达98%。

Effect of Pore Structure of NiW/SAPO-11 on Its Catalytic Performance for Diesel Fuel Hydroisomerization Dewaxing

Hydroisomerization dewaxing catalyst NiW/SAPO 11 was prepared with SAPO 11 zeolite as acidic carrier instead of ZSM 5 zeolite and NiW double metals as the active components. In the catalyst preparation pore enlarging reagent (carbon black) was used to elevate mass transfer performance of the catalyst and promote the diffusion process of the materials and products. The hydroisomerization dewaxing performance of the prepared C/NiW/SAPO 11 catalyst was evaluated with Changqing straight run diesel oil as raw material in the high pressure fixed bed microreactor. The influence of pore enlarging reagent on the hydroisomerization dewaxing performance of catalysts was investigated. Experimental results showed that the pore volume and the number of large pore of C/NiW/SAPO 11 catalysts increased with the increase of pore enlarging reagent content, so the hydroisomerization dewaxing performance of catalysts was improved. With 7%C/NiW/SAPO 11 as catalyst under the reaction conditions of 340℃,40 MPa、LHSV 10-1 and H2/oil volume ratio 500, the best hydroisomerization dewaxing performance could be obtained, that is, the freezing point of diesel fuel dropped from 0℃ to -28℃ with the diesel yield as high as to 98%.