晶粒度对ZSM-5沸石上C_4液化气低温芳构化反应的影响  

Effect of Crystal Size of ZSM-5 Zeolites on the Low-temperature Aromatization of C_4 Liquefied Petroleum Gas

作　　者：孙琳[1] 叶娜[1] 王祥生[1] 郭洪臣[1] 

机构地区：[1]大连理工大学催化化学与工程系及精细化工国家重点实验室,大连116012

出　　处：《化学通报》2007年第8期633-636,共4页Chemistry

基　　金：中国石油天然气股份有限公司(040508-02-2);辽宁省优秀青年科技人才培养基金(3050004)资助项目

摘　　要：用小型加压固定床反应器对比研究了晶粒度分别为20～50nm(DNZ)、1～2μm(IDG)和3～4μm(NK)的ZSM-5沸石的液化气(含C4烯烃56%、C4烷烃43%)低温芳构化反应性能。用SEM、XRF、XRD、NH3-TPD、吸附量和积炭量测定等方法对催化剂进行了表征。结果表明,纳米沸石催化剂DNZ与微米沸石催化剂IDG、NK虽初始芳构化活性(C5+烃中的芳烃含量)基本相同,但当DNZ、NK、IDG分别运转到192h、144h和168h时,芳烃含量分别降为68%、52%和46%,而积炭量依次为209、162和201mg/g。这是由于纳米ZSM-5沸石具有晶间孔辅助容炭,孔口多和孔道短等特点,因而在液化气低温芳构化反应中表现出比微米ZSM-5沸石更强的抗积炭失活能力。The effect of crystal size of ZSM-5 zeolites on the low-temperature aromatization of C4 liquefied petroleum gas in which containing C4 alkenes （56%） and C4 alkanes （43%） is investigated with three samples, i.e., DNZ （20 ～ 50nm）, IDG （1～ 2μm） and NK （3 ～ 4μm） and a fix-bed reactor. Characterizations are carried out with SEM, XRF, XRD, NH3-TPD, adsorption capacities as well as coke analysis to investigate the different performances of the zeolitic catalysts. Results show that the initial aromatization activity of the nano-sized ZSM-5 zeolite （expressed by the aromatics content in C5^＋ hydrocarbons） is roughly the same as those of the micro-sized zeolites. However, as the time on stream of DNZ, IDG and NK extending to 192h, 168h and 144h, the aromatics content in C5^＋ hydrocarbons decreases to 68% , 52% and 46%, respectively. Meanwhile the coke deposited on these catalysts are 209mg/g, 162mg/g and 201mg/g, respectively. These resuhs show that the nano-sized ZSM-5 zeolite exhibits a stronger ability in resisting pore blockage deactivation compared to the micro-sized ZSM-5 zeolites. The advantage of the nano-size ZSM-5 zeolite is attributed to its shorter channels, more pore mouths and rich intercrystal pores.

关 键 词：晶粒度 ZSM-5沸石分子筛 芳构化 C4液化气 活性稳定性 

分 类 号：O643.32[理学—物理化学]