학술논문
晶粒尺寸对Zn/ZSM-5沸石催化烯烃转化性能的影响 / Effect of Zeolite Crystal Size on the Catalytic Performance of Zn/ZSM-5 Zeolite for Olefin Conversion
Document Type
Academic Journal
Source
石油学报（石油加工） / Acta Petrolei Sinica(Petroleum Processing Section). 40(1):23-36
Subject
Language
Chinese
ISSN
1001-8719
Abstract
将催化裂化汽油中的烯烃转化为高辛烷值的芳烃或异构烷烃是生产国Ⅵ标准清洁汽油的有效途径.锌改性ZSM-5(Zn/ZSM-5)分子筛是目前最好的烯烃芳构化催化剂.通过调整沸石的晶粒尺寸,系统地考察了不同粒径的ZSM-5沸石的酸性与烯烃选择性转化之间的构效关系.XRD、SEM、TEM、UV-Vis、XPS、FT-IR和NH3-TPD表征结果表明:ZSM-5的晶粒尺寸影响分子筛的酸性位分布,最小晶粒尺寸为100～200 nm的Zn/ZSM-5沸石具有最高ZnOH+活性物种的相对含量(Zn物种的57％)和较低的Br?nsted酸与Lewis酸之比(AB/AL=0.15).在反应温度350 ℃、液体进料液时体积空速(LHSV)为1.5h-1、H2(g)和1-己烯(1)体积比为600、氢压为0.1和2.0 MPa条件下,该Zn/ZSM-5沸石催化剂在1-己烯加氢转化反应中分别表现出较高的芳烃选择性(17.2％)和异构烷烃选择性(50.0％).这些数据表明,减小ZSM-5沸石晶粒尺寸有利于促进催化裂化汽油中烯烃向高辛烷值组分进行选择性转化.
Converting olefins in FCC gasoline into high-octane aromatics or iso-alkanes is an effective approach to produce clean gasoline in line with China Ⅵ vehicle emission standard.Zn-modified ZSM-5(Zn/ZSM-5)zeolite has been regarded as the best catalyst for olefin aromatization.The structure-activity relationship between the acid properties of ZSM-5 zeolites with different crystal sizes and the selective conversion of olefins was systematically explored by adjusting the crystal size of zeolite.The XRD,SEM,TEM,UV-vis,XPS,FT-IR and NH3-TPD characterization results show that the crystal size of ZSM-5 has an influence on the distribution of acid sites inside and outside the zeolite,and Zn/ZSM-5 zeolite with the smallest crystal size of 100-200 nm has the highest relative content of ZnOH+active species(57％of all Zn species)and a lower ratio of Br?nsted acid to Lewis acid(AB/AL=0.15).At the reaction temperature of 350 ℃,liquid volume space velocity(LHSV)of 1.5 h-1,volume ratio of H2(g)to 1-hexene(1)of 600,and hydrogen pressures of 0.1 and 2.0 MPa,the Zn/ZSM-5 zeolite catalyst exhibits a high aromatics selectivity(17.2％)and a high iso-alkane selectivity(50.0％)in the hydro-conversion of 1-hexene,respectively.The data indicate that the selective conversion of olefins in FCC gasoline into high-octane components can be promoted by reducing the crystal size of ZSM-5 zeolite.
Converting olefins in FCC gasoline into high-octane aromatics or iso-alkanes is an effective approach to produce clean gasoline in line with China Ⅵ vehicle emission standard.Zn-modified ZSM-5(Zn/ZSM-5)zeolite has been regarded as the best catalyst for olefin aromatization.The structure-activity relationship between the acid properties of ZSM-5 zeolites with different crystal sizes and the selective conversion of olefins was systematically explored by adjusting the crystal size of zeolite.The XRD,SEM,TEM,UV-vis,XPS,FT-IR and NH3-TPD characterization results show that the crystal size of ZSM-5 has an influence on the distribution of acid sites inside and outside the zeolite,and Zn/ZSM-5 zeolite with the smallest crystal size of 100-200 nm has the highest relative content of ZnOH+active species(57％of all Zn species)and a lower ratio of Br?nsted acid to Lewis acid(AB/AL=0.15).At the reaction temperature of 350 ℃,liquid volume space velocity(LHSV)of 1.5 h-1,volume ratio of H2(g)to 1-hexene(1)of 600,and hydrogen pressures of 0.1 and 2.0 MPa,the Zn/ZSM-5 zeolite catalyst exhibits a high aromatics selectivity(17.2％)and a high iso-alkane selectivity(50.0％)in the hydro-conversion of 1-hexene,respectively.The data indicate that the selective conversion of olefins in FCC gasoline into high-octane components can be promoted by reducing the crystal size of ZSM-5 zeolite.