The swirl and pyrolysis reaction synergistically enhance solid-solid heat transfer and product separation in cyclone pyrolyzer--颗粒学报PARTICUOLOGY

Niu, H., Yang, J., Lian, W., Zhang, N., Li, Y., Ren, H., . . . Guan, G. (2024). The swirl and pyrolysis reaction synergistically enhance solid-solid heat transfer and product separation in cyclone pyrolyzer. Particuology, 91, 118-127. https://doi.org/10.1016/j.partic.2024.02.004

The swirl and pyrolysis reaction synergistically enhance solid-solid heat transfer and product separation in cyclone pyrolyzer

Haorui Niu^a, Jingxuan Yang^a *, Wenhao Lian^b, Nan Zhang^a, Yongguo Li^c, Hongzheng Ren^c, Xiaogang Hao^a *, Guoqing Guan^d *

a College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan, 030024, China
b School of Chemical Engineering and Technology, North University of China, Taiyuan, 030051, China
c CNNC Key Laboratory on Radioactive Gas Purification Technology, China Institute for Radiation Protection, Taiyuan, 030006, China
d Energy Conversion Engineering Laboratory, Institute of Regional Innovation, Hirosaki University, 3-Bunkyocho, Hirosaki, 036-8561, Japan

10.1016/j.partic.2024.02.004

Volume 91, August 2024, Pages 118-127

Received 20 December 2023, Revised 3 February 2024, Accepted 16 February 2024, Available online 14 March 2024, Version of Record 21 March 2024.

E-mail: yangjingxuan@tyut.edu.cn; xghao@tyut.edu.cn; guan@hirosaki-u.ac.jp

Highlights

• Effects of gas swirl and pyrolysis on the heat and mass transport are analyzed.

• Heating rate of biomass with pyrolysis is higher than that without reaction.

• Inner cycle of char as new heat carrier with gas swirl enhances heat transfer.

• Pyrolyzed gas products and the heat carrier particles can be separated in time.

Abstract

Cyclone pyrolyzer is a novel type of downer that combines centrifugal force field and double-layer cyclone vortex. Research on transfer behavior is helpful to optimize the pyrolyzer to meet the needs of pyrolysis. In this study, the Computational Particle Fluid Dynamics (CPFD) model is used to analyze the transfer behavior of binary particles, and finds that the swirl and reaction have a synergistic effect. This effect can increase the heating rate of the particles to the range of flash pyrolysis, and its mechanism lies in the flow field structure of the pyrolyzer. Due to the centrifugal force field, the particles gather to the near wall. The rapid swirl, which facilitates intense gas-solid heat transfer, leads to the rapid heating and pyrolysis of biomass particles. As the pyrolysis proceeds, the mass of the biomass particles becomes smaller and they are more easily affected by the gas flow in pyrolyzer. Under the action of gas flow, char particles serve as new heat carrier to form the inner cycle of particles, which strengthens the heating process. The pyrolysis products are discharged from the exhaust port in time with the flow field of the pyrolyzer to achieve separation from the heat carrier and inhibit the occurrence of secondary reactions.

Graphical abstract

Keywords

Biomass pyrolysis; Cyclone pyrolyzer; Intra-particle circulation; Synergistic effect

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