Study of biomass gasification in an industrial-scale dual circulating fluidized bed (DCFB) using the Eulerian-Lagrangian method (Open Access)--颗粒学报PARTICUOLOGY

Yu, J., Wang, S., Luo, K., Li, D., & Fan, J. (2023). Study of biomass gasification in an industrial-scale dual circulating fluidized bed (DCFB) using the Eulerian-Lagrangian method. Particuology, 83, 156-168. https://doi.org/10.1016/j.partic.2023.02.018

Study of biomass gasification in an industrial-scale dual circulating fluidized bed (DCFB) using the Eulerian-Lagrangian method (Open Access)

Jiahui Yu ^a, Shuai Wang ^a, Kun Luo ^{a b *}, Debo Li ^c, Jianren Fan ^{a b}

a State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
b Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, 200120, China
c Guangdong Diankeyuan Energy Technology Co., Ltd., Guangzhou, 510080, China

10.1016/j.partic.2023.02.018

Volume 83, December 2023, Pages 156-168

Received 21 December 2022, Revised 17 February 2023, Accepted 26 February 2023, Available online 10 March 2023, Version of Record 16 March 2023.

E-mail: zjulk@zju.edu.cn

Highlights

• Biomass gasification in an industrial-scale dual circulating fluidized bed was studied.

• Size-/density-induced segregation makes solid fuels concentrate on the bed surface.

• Temperature in the combustor is about 100 K higher than that in the gasifier.

• HTCs are 50–150 W/(m² K) in the combustor and 100–200 W/(m² K) in the gasifier.

• Reynolds number of biomass particles is two orders of magnitude larger than sand particles.

Abstract

Dual circulating fluidized bed (DCFB) has emerged as an efficient reactor for biomass gasification due to its unique feature of high gas-solid contact efficiency and separated reactions in two reactors, yet the understanding of complex in-furnace phenomena is still lacking. In this study, biomass gasification in an industrial-scale DCFB system was numerically studied using a multiphase particle-in-cell (MP-PIC) method featuring thermochemical sub-models (e.g., heat transfer, heterogeneous reactions, and homogeneous reactions) under the Eulerian-Lagrangian framework. After model validation, the hydrodynamics and thermochemical characteristics (i.e., pressure, temperature, and species) in the DCFB are comprehensively investigated. The results show that size-/density-induced segregation makes solid fuels concentrate on the bed surface. Interphase momentum exchange leads to the continuous decrease of the gas pressure axially. In the gasifier and combustor, the lower heating value (LHV) of the gas products is 5.56 MJ/Nm³ and 0.2 MJ/Nm³ and the combustible gas concentration (CGC) is 65.5% and 1.86%, respectively. The temperature in the combustor is about 100 K higher than that in the gasifier. A higher solid concentration results in a smaller value of particle heat transfer coefficient (HTC). The HTCs range from 50 to 150 W/(m² K) for a solid concentration larger than 0.3 in the combustor while the HTCs range from 100 to 200 W/(m² K) in the gasifier. The Reynolds number of biomass particles is two orders of magnitude larger than that of the sand particle. The numerical results shed light on the reactor design and process optimization of biomass gasification in DCFBs.

Graphical abstract

Keywords

Dual fluidized bed; Biomass gasification; Numerical simulation; MP-PIC; Heat transfer coefficient

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