SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2021, Vol. 35 ›› Issue (7): 231-238.DOI: 10.1016/j.cjche.2021.07.009

• Catalysis, Kinetics and Reaction Engineering • Previous Articles     Next Articles

Kinetics of steam regeneration of SAPO-34 zeolite catalyst in methanol-to-olefins (MTO) process

Huaiqing An1,2, Hua Li1, Jibin Zhou1, Jinling Zhang1, Tao Zhang1, Mao Ye1, Zhongmin Liu1,2   

  1. 1. National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-04-14 Revised:2021-07-18 Online:2021-09-30 Published:2021-07-28
  • Contact: Mao Ye
  • Supported by:
    We are grateful to the National Natural Science Foundation of China (91834302).

Kinetics of steam regeneration of SAPO-34 zeolite catalyst in methanol-to-olefins (MTO) process

Huaiqing An1,2, Hua Li1, Jibin Zhou1, Jinling Zhang1, Tao Zhang1, Mao Ye1, Zhongmin Liu1,2   

  1. 1. National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • 通讯作者: Mao Ye
  • 基金资助:
    We are grateful to the National Natural Science Foundation of China (91834302).

Abstract: Methanol-to-olefins (MTO) is industrially applied to produce ethylene and propylene using methanol converted from coal, synthetic gas, and biomass. SAPO-34 zeolites, as the most efficient catalyst in MTO process, are subject to the rapid deactivation due to coke deposition. Recent work shows that steam regeneration can provide advantages such as low carbon dioxide emission and enhanced light olefins yield in MTO process, compared to that by air regeneration. A kinetic study on the steam regeneration of spent SAPO-34 catalyst has been carried out in this work. In doing so, we first investigated the effect of temperature on the regeneration performance by monitoring the crystal structure, acidity, residual coke properties and other structural parameters. The results show that with the increase of regeneration temperature, the compositions of residual coke on the catalyst change from pyrene and phenanthrene to naphthalene, which are normally considered as active hydrocarbon pool species in MTO reaction. However, when the regeneration temperature is too high, nitrogen oxides can be found in the residual coke. Meanwhile, as the regeneration temperature increases, the quantity of residual coke reduces and the acidity, BET surface area and pore structure of the regenerated samples can be better recovered, resulting in prolonging catalyst lifetime. We have further derived the kinetics of steam regeneration, and obtained an activation energy of about 177.8 kJ·mol-1. Compared that with air regeneration, the activation energy of steam regeneration is higher, indicating that the steam regeneration process is more difficult to occur.

Key words: Methanol to olefins (MTO), SAPO-34 zeolite catalyst, Steam regeneration, Regeneration kinetics

摘要: Methanol-to-olefins (MTO) is industrially applied to produce ethylene and propylene using methanol converted from coal, synthetic gas, and biomass. SAPO-34 zeolites, as the most efficient catalyst in MTO process, are subject to the rapid deactivation due to coke deposition. Recent work shows that steam regeneration can provide advantages such as low carbon dioxide emission and enhanced light olefins yield in MTO process, compared to that by air regeneration. A kinetic study on the steam regeneration of spent SAPO-34 catalyst has been carried out in this work. In doing so, we first investigated the effect of temperature on the regeneration performance by monitoring the crystal structure, acidity, residual coke properties and other structural parameters. The results show that with the increase of regeneration temperature, the compositions of residual coke on the catalyst change from pyrene and phenanthrene to naphthalene, which are normally considered as active hydrocarbon pool species in MTO reaction. However, when the regeneration temperature is too high, nitrogen oxides can be found in the residual coke. Meanwhile, as the regeneration temperature increases, the quantity of residual coke reduces and the acidity, BET surface area and pore structure of the regenerated samples can be better recovered, resulting in prolonging catalyst lifetime. We have further derived the kinetics of steam regeneration, and obtained an activation energy of about 177.8 kJ·mol-1. Compared that with air regeneration, the activation energy of steam regeneration is higher, indicating that the steam regeneration process is more difficult to occur.

关键词: Methanol to olefins (MTO), SAPO-34 zeolite catalyst, Steam regeneration, Regeneration kinetics