Chemical Industry and Engineering Progree ›› 2015, Vol. 34 ›› Issue (1): 150-155.DOI: 10.16085/j.issn.1000-6613.2015.01.026

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Performance of Pt/Al2O3-Cl catalysts for C5/C6 paraffin isomerization

LI Yong, ZHANG Kongyuan, ZHU Hongwei, YANG Kang, LIU Chenguang   

  1. State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, CNPC, China University of Petroleum, Qingdao 266580, Shandong, China
  • Received:2014-06-03 Revised:2014-06-21 Online:2015-01-05 Published:2015-01-05

C5/C6烷烃异构化Pt/Al2O3-Cl催化剂的性能

李勇, 张孔远, 朱红伟, 杨康, 刘晨光   

  1. 中国石油大学重质油国家重点实验室, CNPC催化重点实验室, 山东 青岛 266580
  • 通讯作者: 张孔远,博士,高级工程师。E-mail zkyuana@126.com。
  • 作者简介:李勇(1988-),男,硕士研究生,研究方向为石油与天然气加工。E-mail liyongfighting@126.com。
  • 基金资助:

    国家重点基础研究发展计划(2010CB226905)及国家自然科学基金(21176258,U1162203)项目。

Abstract: Pt/Al2O3 catalyst was prepared by impregnation. The Pt/Al2O3-Cl catalyst was derived from Pt/Al2O3, and chlorided by CCl4 at 300℃ for one hour. The characterization techniques, such as FT-IR, XRD, TEM, CO-IR, Py-IR and TPD, were employed. The performance of Pt/Al2O3-Cl catalyst was compared with that of RISO catalyst. The experimental results show that the OH groups are replaced by chorine in the process of chlorination, leading to a great decrease in the range of high wavenumbers (3000—3800cm-1). The structure of alumina does not appear modified upon chlorination. The chlorinated Pt/Al2O3 catalyst exhibits a broad particle size distribution with a larger mean particle size, leading to very low metal dispersion. Simultaneously, platinum is oxidized to platinum chloride, which reacts with AlCl3 to produce the volatile PtCl2·2AlCl3 complex, so a loss of platinum is observed. Only Lewis acid sites are detected on the fresh catalyst. However, both Lewis and Bronsted acid sites are detected on used catalyst. The chlorinated Pt/Al2O3 catalyst is quite unstable, as shown by continuous release of three kinds of Cl species during TPD measurement. The performance of Pt/Al2O3-Cl catalyst is better than that of RISO catalyst. The n-hexane conversion and 2, 2-DMB selectivity are 88.17% and 29.68%, respectively. The hydrogenolysis and hydrocracking of hexane are very limited.

Key words: isomerization, Pt/Al2O3-Cl, chlorination, hexane, particle

摘要: 采用浸渍法制备了Pt/Al2O3,在300℃、CCl4氯化1h,制备出Pt/Al2O3-Cl催化剂。采用FT-IR、XRD、TEM、CO-IR、Py-IR和TPD等方法表征了催化剂,并与中温型RISO催化剂的催化性能进行比较。结果表明,在氯化处理过程中氯取代了氧化铝的表面羟基,导致3000~3800cm-1红外吸收峰强度大幅度减小,但催化剂的晶相不发生改变;氯化使Pt粒子的平均粒径增大,粒径分布变宽,金属分散度降低;氯化后金属Pt主要以+2价的PtCl2的形式出现,其中一部分生成了易升华的PtCl2·2AlCl3,从而导致Pt含量降低;氯化后的催化剂上只有L酸,评价后既有L酸,又有B酸;氯化后的催化剂热稳定不高,随着温度升高,3种类型的氯化物相继脱出;Pt/Al2O3-Cl相对于中温型RISO催化剂表现出较好的异构化性能,正己烷转化率达88.17%,2,2-二甲基丁烷选择性达29.68%,裂化和氢解几乎没有发生。

关键词: 异构化, Pt/Al2O3-Cl, 氯化, 正己烷, 粒子

CLC Number: 

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