SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2020, Vol. 28 ›› Issue (3): 793-807.DOI: 10.1016/j.cjche.2019.09.010

• Catalysis, Kinetics and Reaction Engineering • 上一篇    下一篇

Numerical investigation of complex chemistry performing in Ptcatalyzed oxidative dehydrogenation of ethane fixed-bed reactors

Zhongfeng Geng, Hao Deng, Yonghui Li, Minhua Zhang   

  1. Key Laboratory for Green Chemical Technology of Ministry of Education, R & D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China;Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
  • 收稿日期:2019-03-03 修回日期:2019-08-05 出版日期:2020-03-28 发布日期:2020-06-11
  • 通讯作者: Minhua Zhang

Numerical investigation of complex chemistry performing in Ptcatalyzed oxidative dehydrogenation of ethane fixed-bed reactors

Zhongfeng Geng, Hao Deng, Yonghui Li, Minhua Zhang   

  1. Key Laboratory for Green Chemical Technology of Ministry of Education, R & D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China;Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
  • Received:2019-03-03 Revised:2019-08-05 Online:2020-03-28 Published:2020-06-11
  • Contact: Minhua Zhang

摘要: Ethylene is one of the most important basic chemicals in the modern chemical industry. Thermal or catalytic cracking of hydrocarbons is the main industrial technologies nowadays, which suffer from equilibriumlimitation and rapid coke formation. The oxidative dehydrogenation of ethane (ODHE) is considered to be a promising alternative process since it overcomes equilibrium-limitations, avoids catalyst deactivation by coke formation, and decreases the number of side reactions. In this study, particle-resolved 2D CFD simulations of fixed-beds filled with eggshell catalysts coupled with micro-kinetics of Pt-catalyzed ODHE were performed to understand the effect of operation conditions and catalyst properties on ethylene selectivity. The catalyst bed was created by discrete element method (DEM) and the central longitudinal section of the reactor tube was defined as the 2D simulation region. Both of the homogeneous and catalytic heterogeneous chemical reactions were described by detailed micro-kinetics within the particle-resolved CFD simulation. At first, the established model of monolith reactors was verified by comparing the simulated results with experimental results reported in literature. Then, the effects of operation conditions and catalyst concentration on the ethylene selectivity in randomly packed beds were explored. The specific variation of certain operation conditions including inlet flow rate, inlet temperature, pressure, inlet C2H6/O2 ratio and N2 dilution ratio can effectively increase ethylene selectivity. And the reduction of ratio of catalytic active area to geometric area Fcat/geo representing catalyst properties from 140 to 30 increases the selectivity from 42.2% to 59.3%. This research can provide reference for the industrialization of ODHE process in the future.

关键词: Ethane, Ethylene, Oxidative dehydrogenation, Selectivity, CFD, Fixed-bed

Abstract: Ethylene is one of the most important basic chemicals in the modern chemical industry. Thermal or catalytic cracking of hydrocarbons is the main industrial technologies nowadays, which suffer from equilibriumlimitation and rapid coke formation. The oxidative dehydrogenation of ethane (ODHE) is considered to be a promising alternative process since it overcomes equilibrium-limitations, avoids catalyst deactivation by coke formation, and decreases the number of side reactions. In this study, particle-resolved 2D CFD simulations of fixed-beds filled with eggshell catalysts coupled with micro-kinetics of Pt-catalyzed ODHE were performed to understand the effect of operation conditions and catalyst properties on ethylene selectivity. The catalyst bed was created by discrete element method (DEM) and the central longitudinal section of the reactor tube was defined as the 2D simulation region. Both of the homogeneous and catalytic heterogeneous chemical reactions were described by detailed micro-kinetics within the particle-resolved CFD simulation. At first, the established model of monolith reactors was verified by comparing the simulated results with experimental results reported in literature. Then, the effects of operation conditions and catalyst concentration on the ethylene selectivity in randomly packed beds were explored. The specific variation of certain operation conditions including inlet flow rate, inlet temperature, pressure, inlet C2H6/O2 ratio and N2 dilution ratio can effectively increase ethylene selectivity. And the reduction of ratio of catalytic active area to geometric area Fcat/geo representing catalyst properties from 140 to 30 increases the selectivity from 42.2% to 59.3%. This research can provide reference for the industrialization of ODHE process in the future.

Key words: Ethane, Ethylene, Oxidative dehydrogenation, Selectivity, CFD, Fixed-bed