Title: The cooling range of liquid CO₂ on loose coal through experimental investigation

Authors: Xiaowei Zhai; Hui Ge; Dariusz Obracaj

Addresses: School of Safety Science and Engineering, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, Shaanxi 710054, China ' School of Safety Science and Engineering, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, Shaanxi 710054, China ' Faculty of Mining and Geoengineering, AGH University of Science and Technology, Cracow, PL-30059, Poland

Abstract: An experimental platform was used to evaluate the cooling characteristics of liquid CO₂ on coal by changing the mass flow rate and the diameter of injection nozzle. The results show that coal temperature was affected by the phase transition of liquid CO₂. Two cooling regions were formed in the vertical sections which would disseminate and finally overlap. In the horizontal sections, the cold volume was reduced from injection centre to the two sides. The functions of furthest cooling influence for both different injection nozzles and different mass flow rates correspond to different nonlinear logarithmic functions. Changing the diameter of injection nozzle had a more promoting effect on cooling range than changing the mass flow rate of liquid CO₂. Moreover, parameter K was introduced to estimate the cooled coal volume. The above results could provide a guideline for onsite coal fire prevention and liquid CO₂ cooling. [Received: August 10, 2019; Accepted: March 7, 2020]

Keywords: spontaneous coal combustion; SCC; liquid CO₂ injection; cooling phenomena; phase transition; cooling influence; cooling parameter.

DOI: 10.1504/IJOGCT.2021.114860

International Journal of Oil, Gas and Coal Technology, 2021 Vol.27 No.1, pp.54 - 77

Received: 10 Aug 2019
Accepted: 07 Mar 2020
Published online: 10 May 2021 *

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