石油学报(石油加工) ›› 2020, Vol. 36 ›› Issue (3): 543-550.doi: 10.3969/j.issn.1001-8719.2020.03.014

• 研究报告 • 上一篇    下一篇

不同碳数脂肪酸甲酯在HZSM-5分子筛中吸附行为的分子模拟

党宇,李瑞英,闫昊,刘熠斌,冯翔,金鑫,陈小博,杨朝合   

  1. 中国石油大学(华东)重质油国家重点实验室,山东 青岛 266580
  • 收稿日期:2019-04-15 修回日期:2019-12-09 出版日期:2020-05-25 发布日期:2020-07-21
  • 通讯作者: 刘熠斌,男,副教授,博士,从事石油与天然气加工方面的研究,Tel:0532-86980917, E-mail:liuyibin@upc.edu.cn E-mail:lyb3028@126.com
  • 作者简介:第一作者:党宇,男,硕士研究生,从事石油天然气加工和分子模拟方面的研究
  • 基金资助:
    国家自然科学基金项目(21476263, 21776312)和中央高校基本科研业务费专项资金(18CX02130A)资助

Molecular Simulations of Adsorption of Linear Fatty Acid Methyl Esters With Different Carbon Numbers in HZSM-5 Zeolite

DANG Yu, LI Ruiying, YAN Hao, LIU Yibin, FENG Xiang, JIN Xin, CHEN Xiaobo, YANG Chaohe   

  1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
  • Received:2019-04-15 Revised:2019-12-09 Online:2020-05-25 Published:2020-07-21

摘要: 采用巨正则蒙特卡洛(GCMC)方法,从反应前驱步骤——吸附出发,在298~473 K下考察了C3~C7直链脂肪酸甲酯在HZSM-5分子筛中的吸附行为。结果表明:HZSM-5催化剂中存在两类吸附位点,分别在孔道交叉处(site I)和直孔道中(site II),并且氢键的形成导致客体分子和site I作用更强;升高温度降低了客体分子和吸附位点的作用强度,使饱和吸附量略有下降。此外,随着碳链长度增加,脂肪酸甲酯的空间位阻增大,体系中氢键数目降低,氢键键长增加,导致长链分子的吸附量显著下降。以上模拟结果从微观角度揭示了温度和链长对脂肪酸甲酯吸附性质的影响,为不同链长油脂分子催化裂解反应特性研究提供了理论指导。

关键词: 脂肪酸甲酯, HZSM-5分子筛, 吸附, 巨正则蒙特卡洛(GCMC)

Abstract: The adsorption behavior of C3-C7 linear fatty acid methyl ester in HZSM-5 zeolite were investigated by grand cononical Monte Carlo (GCMC) method from the perspective of reaction precursor-adsorption. The results demonstrate that there are two types of adsorption sites in the catalyst, which are at the intersection of the channel (site I) and the straight channel (site II), respectively. The formation of hydrogen bonds leads to stronger interactions between the guest molecule and site I. Increasing temperature lowers the intensity of interactions between molecules and adsorption sites, causing a slight decrease of saturated amount. Moreover, the molecular steric hindrance increases with the increase of the chain length. While the number of hydrogen bonds decreases, and the bond length increases, the adsorption capacity of long-chain molecules decreases significantly. The results reveal the effect of temperature and chain length on the adsorption properties of fatty acid methyl esters from a microscopic perspective, which provides theoretical guidance for the study of catalytic cracking reaction characteristics of different chain length oil molecules.

Key words: fatty acid methyl ester, HZSM-5;adsorption, grand canonical Monte Carlo(GCMC)