Blasting Law of Liquid CO2 Phase Change in Coal Mine Based on Numerical Simulation

Abstract

In order to obtain the best CO2 blasting drilling efficiency and improve the gas permeability coefficient of the coal seam in the mining area, a research method of liquid CO2 phase change blasting in the coal seam based on electrochemical numerical simulation is proposed. In this paper, the electrochemical numerical simulation of coalbed methane caused by liquid CO2 phase change blasting is studied through theoretical analysis, the antireflection mechanism of liquid carbon dioxide gas explosion on broken coal seam is obtained, and the initial fracture length of coal body caused by gas explosion stress wave is deduced by the mathematical model. A method for improving CBM desorption with nonmechanical coal was proposed, namely, a method for electrochemically strengthening CBM desorption. A comprehensive theory and application system of liquid carbon dioxide phase change gas explosion and anti-reflection technology are established by combining theoretical analysis, experimental research, and numerical simulation with field industrial comparative experiment. According to the gas tracing method, the precise measurement of the working face shows that the impact radius of the collision caused by the explosion of the liquid carbon dioxide phase change gas is 2 m. Gas emissions increased the emissions of coal seam drilling in the affected areas by 4 to 8 times, and the gas emission attenuation coefficient decreased from 0.76 times to 0.93 times. The carbon dioxide phase change gas cracking theory and antireflection theory and their application technology system are systematically studied. The research shows that the liquid carbon dioxide phase transfer gas blasting and infiltration technology is not limited by the geological conditions of the coal seam and has the characteristics of high efficiency and inherent climate. In view of the wide area of coal mines and the harsh geological conditions of coal seams, carbon dioxide phase change gas-induced cracking antireflection technology has application prospects and expandability.