液态二氧化碳相变致裂在煤矿瓦斯灾害中的试验研究

Experimental study on Cracking Caused by Phase Change of Liquid Carbon Dioxide in Coal Mine Gas Disaster

矿井瓦斯的抽采是高瓦斯突出煤矿的一项重要工作,如何提高瓦斯的抽采浓度和抽采量一直是煤矿技术人员探索的方向。项目试验利用液态二氧化碳相变致裂技术在煤矿瓦斯灾害中的防治,通过低温液态CO2相变过程中,在煤岩体中形成一个低应力、高渗透性的卸压区域,加快煤体中原生瓦斯的游离态化,实现低透气性煤层的瓦斯强化抽采。经过现场试验证明,能够提高钻孔瓦斯抽采浓度和减少瓦斯衰减时间2倍以上,且操作简单,不产生高温和明火,具有经济、安全、高效等优点,可以在瓦斯矿井中推广应用。

Gas extraction is an important work in high gas outburst coal mine, therefore, it has always been the direction of research for coal mine technicians on how to improve the concentration and purity of gas extraction. The cracking technology of liquid carbon dioxide phase change is applied to this project to prevent coal mine gas disaster. A safe region with low stress and high permeability is formed in the coal seam by cracking of phase transition of liquid CO2, which can accelerate the transformation of gas from adsorption state to free state, and achieve gas-enhanced extraction of low permeability coal seams. The field test shows that this methodology can improve the gas extraction concentration and reduce the gas attenuation time by more than 2 times. Furthermore, it has simple operation process without high temperature and naked light. The method proposed in this project is suggested to be widely applied to gas mines due to its economy, safety,efficiency, etc.