Study on gas seepage characteristics of loose coal

ZHENG Xuezhao; FAN Yongchao; YAN Ruijin; SUN Ziyu; HUANG Yuan

doi:10.13347/j.cnki.mkaq.20231367

Abstract：In order to study the influence of temperature on the gas seepage law in loose coal bodies in goaf,gas seepage characterist-ics experiments were conducted on three types of coal samples,namely anthracite,bituminous coal,and lignite,under different tem-perature conditions using a self-developed loose coal temperature seepage comprehensive experimental platform,and COMSOL Multiphysics was used to simulate the gas seepage process through bituminous coal under constant temperature and continuous heat-ing conditions.By studying the gas seepage law when there is a local heat source in the loose coal body in the goaf,a temperature based on gas seepage model for the loose coal body was established.Under constant temperature conditions ranging from 30℃to 80℃,when air passes through loose and broken anthracite,bituminous coal,and lignite at a speed of less than 1.0 cm/s,it follows the lin-ear Darcy flow law,and the pressure gradient gradually increases with the increase of specific flow rate;the permeability of coal de-creases with increasing temperature,and the permeability changes of different coal samples vary with increasing temperature,and brown coal>bituminous coal>anthracite;as the temperature increases,the temperature distribution and permeability distribution in-side the coal pillar can be approximated as an"ellipsoidal shell"near the gas outlet.