Influence of pore structure on thermal stress distribution inside coal particles during primary fragmentation--颗粒学报PARTICUOLOGY

Qiao, K., Zhong, S., Tang, S., Yang, K., Yue, H., Ma, K., . . . Liang, B. (2024). Influence of pore structure on thermal stress distribution inside coal particles during primary fragmentation. Particuology, 85, 49-61. https://doi.org/10.1016/j.partic.2023.03.021

Influence of pore structure on thermal stress distribution inside coal particles during primary fragmentation

Kai Qiao ^a, Shan Zhong ^a *, Siyang Tang ^a, Ke Yang ^a, Hairong Yue ^{a b}, Kui Ma ^a, Lei Song ^a, Bin Liang ^{a b}

a School of Chemical Engineering, Sichuan University, Chengdu, 610065, China
b Institute of New Energy and Low-carbon Technology, Chengdu, 610207, China

10.1016/j.partic.2023.03.021

Volume 85, February 2024, Pages 49-61

Received 28 September 2022, Revised 27 February 2023, Accepted 23 March 2023, Available online 13 April 2023, Version of Record 19 April 2023.

E-mail: zhongshan@scu.edu.cn

Highlights

• Relationship between thermal stress and pore curvature was revealed.

• Pores affect the thermal stress more significantly at particle center and surface.

• Mean maximum thermal tensile stress linearly increases with increasing porosity.

• Thermal stress induced fragmentation is easier to occur for high porosity particles.

Abstract

Thermal stress is an important reason of coal particle primary fragmentation, during which the role of pore structure is ambiguous. Thermal stress induced fragmentation experiments were conducted with low volatile coal/char particles, and the results show that the fragmentation severity enhances with increasing porosity. Various porous thermal stress models were developed with finite element method, and the influences of the pore shape, size, position and porosity on the thermal stress were discussed. The maximum thermal stress inside particle increases with pore curvature, the pore position affects the thermal stress more significantly at the particle center and surface. The expectation of the maximum tensile thermal stress linearly increases with porosity, making the particles with higher porosity easier to fragment, contrary to the conclusion deduced from the devolatilization theory. The obtained results are valuable for the analysis of different thermal processes concerning the thermal stresses of the solid feedstocks.

Graphical abstract

Keywords

Coal particle; Primary fragmentation; Thermal stress; Pore structure; Porosity

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