Gas Emission Characteristics of Coal Particles Without Local Resistance and Optimization of the Emission Model

The local resistance of the pipeline in the experimental device has an important influence on the speed of gas emission. The purpose of this study is to reveal the characteristics of gas emission from coal particles under the condition of no local resistance. Through the self-developed experimental device for gas emission from coal particles without local resistance, the rapid release of valves is realized, and the interference of local resistance on gas-free emission is eliminated. The results show that, under the condition of no local resistance experiment, the adsorption equilibrium pressure is positively correlated with the cumulative gas emission and the emission rate, and the coal particle size is negatively correlated with the two. And the diffusion amount and diffusion speed of the nonlocal resistance experiment in the initial stage of gas diffusion are greater than those of the resistance experiment. Based on the experimental conditions of no local resistance diffusion, the diffusion amounts of 0.5-1 mm and 2-3 mm in the first second accounted for more than 70% of the total amount, and the coal was crushed during the diffusion process. The unimpeded diffusion was divided into instantaneous and continuous diffusion periods, and the segmented model was established and optimized. The average fitting degree was more than 0.99, and the rationality of the segmented model was evaluated. This study reveals the law of coal particle gas emission after eliminating the influence of local resistance, which provides an important theoretical basis and experimental support for accurate prediction of gas emission.