Hydrodynamics and OCM reaction performance in a bubbling fluidized bed reactor and a riser reactor--颗粒学报PARTICUOLOGY

Cai, M., Kong, S., Chen, S., Liu, M., & Lu, C. (2024). Hydrodynamics and OCM reaction performance in a bubbling fluidized bed reactor and a riser reactor. Particuology, 86, 188-204. https://doi.org/10.1016/j.partic.2023.05.008

Hydrodynamics and OCM reaction performance in a bubbling fluidized bed reactor and a riser reactor

Min Cai ^a, Shuangzhu Kong ^a, Sheng Chen ^b, Mengxi Liu ^a *, Chunxi Lu ^a

a State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, 102249, China
b China Special Equipment Inspection and Research Institute, Beijing, 102249, China

10.1016/j.partic.2023.05.008

Volume 86, March 2024, Pages 188-204

Received 13 April 2023, Revised 16 May 2023, Accepted 16 May 2023, Available online 8 June 2023, Version of Record 17 June 2023.

E-mail: mengxiliu@sina.com; liumx@cup.edu.cn

Highlights

• Riser reactor can achieve isothermal operation for the OCM process.

• Consecutive reactions of ethylene are negligible due to the plug flow structure and low solids holdup in the riser.

• C₂ yield of 21.1% is obtained in the riser reactor, increasing by 5.8% than that in the BFB.

• In the BFB, the C₂H₄ concentration quickly increases and then sharply declines with H.

Abstract

The reasonable reactor design is of great importance for increasing the C₂ yield (C₂H₄ and C₂H₆) of the oxidative coupling of methane (OCM), and the OCM reactor should remove the heat released in reactions quickly and efficiently and minimize the consecutive reaction of ethylene to carbon oxides. The fluidized bed reactor is characterized by excellent heat transfer, superior mass transport, and large handling capacity, while fewer studies focused on large-scale fluidized bed reactors for the OCM reaction. Therefore, large cold-model experiments and computational fluid dynamics simulations were conducted to investigate hydrodynamics and the OCM reaction performance in a large-scale bubbling fluidized bed (BFB) and a large-scale riser. In the BFB reactor, consecutive reactions of ethylene are acute because of the strong gas back-mixing, high solids holdup, and non-uniform solids distribution. While the consecutive reactions of ethylene are negligible due to the plug flow structure and low solids holdup in the riser reactor. Further, both reactors can achieve isothermal operation for the OCM process. The C₂ selectivity of 45.4% and C₂ yield of 21.1% are obtained in the riser reactor, increasing by 20.3% and 5.8% individually than that in the BFB reactor. This study provides useful information and reference to the OCM reactor design and commercialization.

Graphical abstract

Keywords

Oxidative coupling of methane; Bubbling fluidized bed reactor; Riser reactor; Hydrodynamics; Isothermal operation

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