The hydroisomerization catalyst is a metal-acid bifunctional catalyst that provides addition dehydrogenation function by metal component, and acidic component provides isomerization function. Hydroisomerization can effectively reduce oil pour point, provide low-temperature flow performance, and improve oil quality. The ZSM-22 zeolite was modified by ion exchange, molding and loading methods to obtain different Zn loadings. The physicochemical properties were characterized by X-ray diffraction (XRD), N2 physical adsorption-desorption (BET), X-ray fluorescence (XRF) and pyridine adsorption infrared (Py-IR). Ni-based hydroisomerization catalyst was prepared by using modified ZSM-22 zeolite as an acidic component and Ni as a metal component. The heterogeneous pour point depressing performance was evaluated by using Fischer–Tropsch heavy diesel oil as a raw material in the fixed bed reactor. Liquid and gas products were measured by off-line gas chromatography and on-line gas chromatography to calculate diesel yield. The results showed that ion exchange had little effect on the zeolite structure, and Zn species were highly dispersed on the surface of the zeolite. The Br?nsted (B) acid content of the catalyst had a significant effect on the activity. The higher B acid content, the higher activity of the catalyst. The introduction of Zn in the zeolite reduced the acidity ratio of B acid to Lewis (L) acid (B/L). With the increase of Zn content, the B/L value decreased, the yield of isomeric hydrocarbon increased, the cracking reaction was effectively inhibited, and the diesel yield was improved. Loading Zn could significantly reduce the cold filter point of heavy filter, and the cold filter point rose with Zn load content increased gradually. When the metal hydrogenation performance was the same, the matching of the metal and acid sites on the catalyst and the heterogeneous performance of the heavy diesel were improved with the decrease of B acid content. When the cold filter point of diesel reached the requirement of -10# diesel of China VI National Standard (cold filter point –5℃), the yield of prepared HI-3 catalyst reached 90.65%.
[[1] 李大东, 加氢处理工艺与工程[M], 中国石化出版社, 北京, 2004.
[2] I.E. Maxwell, Zeolte catalysis in hydroprocessing technology[J], Catal. Today, 1987（1）: 389-417.
[3] J.W. Ward, Hydrocracking processes and catalysts[J], Fuel Process. Technol., 1993(35): 55-85.
[4] H. Xiang, Y. Yang, Y. Li, Indirect coal-to-liquids technology from fundamental research to commercialization[J], Sci. China-Chem., 2014 (44): 1876-1892.
[5] 闫朋辉, 陶智超, 郝坤, 王煜丹, 杨勇, 李永旺, 金属载体结合方式对镍钨催化剂费托合成蜡加氢裂化性能的影响[J], 燃料化学学报, 2013 (41): 691-697.
[6] R.A. Flinn, O.A. Larson, H. Beuther, The Mechanism of Catalytic Hydrocracking[J], Ind. Eng. Chem., 1960 (52): 153–156.
[7] H.L. Coonradt, W.E. Garwood, Mechanism of Hydrocracking [J], Ind. Eng. Chem., 1964 (3): 38-45.
[8] T. Hengsawad, C. Srimingkwanchai, S. Butnark, D.E. Resasco, S. Jongpatiwut, Effect of Metal–Acid Balance on Hydroprocessed Renewable Jet Fuel Synthesis from Hydrocracking and Hydroisomerization of Biohydrogenated Diesel over Pt-Supported Catalysts[J], Industrial & Engineering Chemistry Research, 2018 (57): 1429-1440.
[9] 韩崇仁, 加氢裂化工艺与工程[M], 中国石化出版社, 北京, 2001.
[10] A. Soualah, J.L. Lemberton, L. Pinard, M. Chater, P. Magnoux, K. Moljord, Hydroisomerization of long-chain n-alkanes on bifunctional Pt/zeolite catalysts: Effect of the zeolite structure on the product selectivity and on the reaction mechanism[J], Appl. Catal. A, 2008 (336): 23-28.
[11] 孟庆磊, 刘百军, 盖有东, 何琳琳, Y/ASA复合材料的制备及加氢裂化性能[J], 燃料化学学报, 2012 (40): 354-358.
[12] 张学军, 王宗贤, 郭爱军, 袁宗胜, 王甫村, 高中油型加氢裂化催化剂用Y型沸石的改性研究[J], 燃料化学学报, 2008 (36): 606-609.
[13] 徐如人, 分子筛与多孔材料化学[M], 科学出版社, 北京, 2014.
[14] S. Liu, J. Ren, S. Zhu, H. Zhang, E. Lv, J. Xu, Y.-W. Li, Synthesis and characterization of the Fe-substituted ZSM-22 zeolite catalyst with high n-dodecane isomerization performance[J], J. Catal., 2015 (330): 485-496.
[15] S. HyeonBaeck, W. YoungLee, Dealumination of Mg-ZSM-22 and its use in the skeletal isomerization of 1-butene to isobutene[J], Appl. Catal. A, 1998 (168): 171-177.
[16] Y. Wang, Z. Tao, B. Wu, J. Xu, C. Huo, K. Li, H. Chen, Y. Yang, Y. Li, Effect of metal precursors on the performance of Pt/ZSM-22 catalysts for n-hexadecane hydroisomerization[J], J. Catal., 2015(322): 1-13.
[17] W. Huybrechts, G. Vanbutsele, K.J. Houthoofd, F. Bertinchamps, C.S. Laxmi Narasimhan, E.M. Gaigneaux, J.W. Thybaut, G.B. Marin, J.F.M. Denayer, G.V. Baron, P.A. Jacobs, J.A. Martens, Skeletal isomerization of octadecane on bifunctional ZSM-23 zeolite catalyst[J], Catal. Lett., 2005 (100): 235-242.
[18] S.H. Baeck, K.M. Lee, W.Y. Lee, Skeletal isomerization of 1-butene into isobutene over Mg-ZSM-22 modified by the deposition of silicon alkoxide[J], Catal. Lett., 1998(52): 221-225.
[19] P. Strode, K.M. Neyman, H. Kniizinger, N. Riisch, Acidic properties of [Al], [Ga] and [Fe] isomorphously substituted zeolites. Density functional model cluster study of the complexes with a probe CO molecule[J], Chem. Phy. Letters., 1995 (240): 547-552.
[20] M.S. Stavet, J.B. Nicholas, Density Functional Studies of Zeolites. 2. Structure and Acidity of [T]-ZSM-5 Models (T = B, Al, Ga, and Fe)[J], J. Phys. Chem., 1995 (99): 15046-15061.
[21] S. Liu, J. Ren, H. Zhang, E. Lv, Y. Yang, Y.-W. Li, Synthesis, characterization and isomerization performance of micro/mesoporous materials based on H-ZSM-22 zeolite[J], J. Catal., 2016(335): 11-23.
[22] Z. Chen, S. Liu, H. Wang, Q. Ning, H. Zhang, Y. Yun, J. Ren, Y.-W. Li, Synthesis and characterization of bundle-shaped ZSM-22 zeolite via the oriented fusion of nanorods and its enhanced isomerization performance[J], J. Catal., 2018 (361): 177-185.
[23] Y. Wang, Z. Tao, B. Wu, H. Chen, J. Xu, Y. Yang, Y. Li, Shape-controlled synthesis of Pt particles and their catalytic performances in the n-hexadecane hydroconversion[J], Catal. Today, 2016(259): 331-339.
[24] 董玉林，张玉荣，张群等．ZnO／HZSM-5对环戊烷芳构化催化性能的研究．精细石油化工[J]，1994，(2)：35-39.
[25] 王子建．碳四烯烃芳构化的研究：[学位论文]．北京：石油化工科学研究院，2006.
[26] 潘履让，李牛，唐祥海．正戊烷在HZSM-5及ZnHZSM-5上芳构化反应的研究[J]．南开大学学报(自然科学)，1995，28(1)：28-32.
[27] 徐佩若，班卡拉 ND，吴指南等．碳四烃在改性HZSM-5分子筛上芳构化研究[J]．燃料化学学报，1993，21(2)：127-l34．
