Pt/Hβ临氢异构化催化剂及其还原条件研究
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摘要
以不同硅铝比的Hβ分子筛为载体负载Pt制备Pt/Hβ异构化催化剂。采用低温N_2吸附-脱附和XRD,NH_3-TPD,Py-IR,TEM等方法对催化剂进行表征,在10mL固定床微型反应器(微反)上对不同硅铝比Hβ分子筛制备的Pt/Hβ催化剂和不同还原条件下催化剂的临氢异构化性能进行了评价。结果表明:Hβ分子筛硅铝比对催化剂酸性质和孔结构性质影响明显,随着硅铝比增大,总酸量、中强酸量和B酸量减少,比表面积和孔体积减小,正己烷的转化率增大而异构化率和二甲基丁烷选择性减小;当硅铝比为25时,Pt/Hβ催化剂的异构化性能最好。还原温度和还原压力主要影响催化剂上Pt的粒径大小及其分布,在350℃和0.75MPa条件下还原后,Pt晶粒的平均粒径最小且分布均匀,有利于Pt/Hβ异构化催化剂的活性金属和酸性的匹配,正己烷转化率为81.16%,异构化率为82.89%,二甲基丁烷选择性为25.58%。
The Pt/Hβ isomerization catalysts were prepared by using Hβzeolite with different silica-alumina ratio as the carrier and loaded with Pt.The Pt/Hβ catalysts were characterized by N_2 adsorption-desorption,XRD,NH_3-TPD,Py-IR and TEM.And the isomerization performance of the prepared catalysts was evaluated in a 10 mL fixed-bed micro-reactor.The results showed that the silica-alumina ratio of Hβzeolite has a significant effect on the acidity and pore structure of the catalyst.With the increase of silica-alumina ratio,while the total acid,medium strong acid and Br?nsted acid sites,and the specific surface area and pore volume decrease,which improve the conversion rate of n-hexane and inhibit the isomerization and dimethylbutane selectivity.The Pt/Hβ catalyst with silica-alumina ratio of 25 has the best isomerization performance.Reduction temperature and pressure mainly affects the size and distribution of Pt on the catalyst.At a reduction temperature of 350℃ and a pressure of 0.75 MPa,the average particle size of Pt is the smallest and uniformly distributed,which is beneficial to improve the metallicity and acid matching degree of the catalysts,and the best isomerization results is obtained with the n-hexane conversion rate of 81.16%,isomerization rate of 82.89%,dimethylbutane selectivity of 25.58%.
The Pt/Hβ isomerization catalysts were prepared by using Hβzeolite with different silica-alumina ratio as the carrier and loaded with Pt.The Pt/Hβ catalysts were characterized by N_2 adsorption-desorption,XRD,NH_3-TPD,Py-IR and TEM.And the isomerization performance of the prepared catalysts was evaluated in a 10 mL fixed-bed micro-reactor.The results showed that the silica-alumina ratio of Hβzeolite has a significant effect on the acidity and pore structure of the catalyst.With the increase of silica-alumina ratio,while the total acid,medium strong acid and Br?nsted acid sites,and the specific surface area and pore volume decrease,which improve the conversion rate of n-hexane and inhibit the isomerization and dimethylbutane selectivity.The Pt/Hβ catalyst with silica-alumina ratio of 25 has the best isomerization performance.Reduction temperature and pressure mainly affects the size and distribution of Pt on the catalyst.At a reduction temperature of 350℃ and a pressure of 0.75 MPa,the average particle size of Pt is the smallest and uniformly distributed,which is beneficial to improve the metallicity and acid matching degree of the catalysts,and the best isomerization results is obtained with the n-hexane conversion rate of 81.16%,isomerization rate of 82.89%,dimethylbutane selectivity of 25.58%.
引文
[1]车用汽油:GB 17930-2013[S].北京:中国标准出版社,2013
[2]车用汽油:GB 17930-2016[S].北京:中国标准出版社,2016
[3]张永铭.引进轻石脑油异构化装置的工艺设计[J].石油炼制与化工,2012,43(8):17-21
[4]曾宿主,高鹏,王琪,等.满足国Ⅵ排放标准汽油生产方案的研究[J].石油炼制与化工,2017,48(5):70-75
[5]李永林.增产汽油技术和措施[J].石油炼制与化工,2017,48(5):60-69
[6]Newsam J M,Treacy M M J,Koetsier W T,et al.Structural characterization of zeolite beta[J].Proceedings of the Royal Society of London,1988,420(1859):375-405
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[11]冯延龙,宋月芹,张娟娟,等.Pt?Beta、Pt?SO2-4?ZrO2和Pt?WO3?ZrO2催化剂上的正己烷异构化[J].石油学报(石油加工),2010,26(4):531-537
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[13]赵国良,滕佳伟,谢在库,等.氟硅酸铵改性的HZSM-5催化剂的表征及其烃裂解催化性能[J].催化学报,2005,26(12):1083-1087
[14]朱玉霞,林伟,田辉平,等.固体酸催化剂酸性分析方法的研究进展[J].石油化工,2006,35(7):607-614
[15]唐津莲,许友好,徐莉,等.庚烯与H2S在酸性催化剂上的反应机理:Ⅰ.硫醇、硫醚生成机理[J].石油学报(石油加工),2008,24(2):121-127
[16]Blomsma E,Martens J A,Jacobs P A.Mechanisms of heptane isomerization on bifunctional Pd?H-Beta zeolites[J].JCatal,1996,159(2):323-331
[17]徐铁钢,吴显军,王刚,等.轻质烷烃异构化催化剂研究进展[J].化工进展,2015,34(2):397-401
[18]柴磊昌,施岩.还原条件对磷化镍催化剂的HDN性能影响[J].当代化工,2014(4):498-500
[2]车用汽油:GB 17930-2016[S].北京:中国标准出版社,2016
[3]张永铭.引进轻石脑油异构化装置的工艺设计[J].石油炼制与化工,2012,43(8):17-21
[4]曾宿主,高鹏,王琪,等.满足国Ⅵ排放标准汽油生产方案的研究[J].石油炼制与化工,2017,48(5):70-75
[5]李永林.增产汽油技术和措施[J].石油炼制与化工,2017,48(5):60-69
[6]Newsam J M,Treacy M M J,Koetsier W T,et al.Structural characterization of zeolite beta[J].Proceedings of the Royal Society of London,1988,420(1859):375-405
[7]Higgins J B,Lapierre R B,Schlenker J L,et a1.The framework topology of zeolite beta[J].Zeolites,1988,8(6):446-452
[8]欧阳颖,陈蓓艳,朱根权,等.催化裂化过程中改性Beta分子筛多产异丁烯作用的研究[J].石油炼制与化工,2017,48(11):1-6
[9]Suphot E,Piyasan P,Sipim K,et a1.Isomerization of n-hexane over platinum ion-exchanged zeolite Beta[J].Reaction Kinetics&Catalysis Letters,2000,71(2):281-287
[10]谢有畅,唐有祺.氧化物和盐类在分子筛内外表面及孔穴中的自发分散及其应用[J].北京大学学报(自然科学版),1998,34(2):302-308
[11]冯延龙,宋月芹,张娟娟,等.Pt?Beta、Pt?SO2-4?ZrO2和Pt?WO3?ZrO2催化剂上的正己烷异构化[J].石油学报(石油加工),2010,26(4):531-537
[12]Emeis C A.Determination of integrated molar extinction coefficients for infrared absorption bands of pyridine adsorbed on solid acid catalysts[J].J Catal,1993,141(2):347-354
[13]赵国良,滕佳伟,谢在库,等.氟硅酸铵改性的HZSM-5催化剂的表征及其烃裂解催化性能[J].催化学报,2005,26(12):1083-1087
[14]朱玉霞,林伟,田辉平,等.固体酸催化剂酸性分析方法的研究进展[J].石油化工,2006,35(7):607-614
[15]唐津莲,许友好,徐莉,等.庚烯与H2S在酸性催化剂上的反应机理:Ⅰ.硫醇、硫醚生成机理[J].石油学报(石油加工),2008,24(2):121-127
[16]Blomsma E,Martens J A,Jacobs P A.Mechanisms of heptane isomerization on bifunctional Pd?H-Beta zeolites[J].JCatal,1996,159(2):323-331
[17]徐铁钢,吴显军,王刚,等.轻质烷烃异构化催化剂研究进展[J].化工进展,2015,34(2):397-401
[18]柴磊昌,施岩.还原条件对磷化镍催化剂的HDN性能影响[J].当代化工,2014(4):498-500