Coal seam gas content is frequently measured in quantity during underground coal mining operation and coalbed methane (CBM) exploration as a significant basic parameter. Due to the calculation error of lost gas and residual gas in the direct method, the efficiency and accuracy of the current methods are not inadequate to the large area multi-point measurement of coal seam gas content. This paper firstly deduces a simplified theoretical dynamic model for calculating lost gas based on gas dynamic diffusion theory. Secondly, the effects of various factors on gas dynamic diffusion from coal particle are experimentally studied. And sampling procedure of representative coal particle is improved. Thirdly, a new estimation method of residual gas content based on excess adsorption and competitive adsorption theory is proposed. The results showed that the maximum error of calculating the losing gas content by using the new simplified model is only 4%. Considering the influence of particle size on gas diffusion law, the particle size of the collected coal sample is below 0.25 mm, which improves the measurement speed and reflects the safety representativeness of the sample. The determination time of gas content reduced from 36 to 3 h/piece. Moreover, the absolute error is 0.15–0.50 m³/t, and the relative error is within 5%. A new engineering method for determining the coal seam gas content is developed according to the above research.

在地下煤矿开采和煤层气（CBM）勘探期间，煤层气含量经常作为重要的基本参数进行量度。由于直接法中损失气体和残留气体的计算误差，现有方法的效率和准确性不足以对煤层瓦斯含量进行大面积多点测量。本文首先基于气体动态扩散理论推导了一种简化的理论计算漏气的理论动力学模型。其次，实验研究了各种因素对煤颗粒气体动态扩散的影响。改进了代表性煤粉的采样程序。第三，提出了一种基于过量吸附和竞争吸附理论的剩余气含量估算方法。结果表明，使用新的简化模型计算损失气体含量的最大误差仅为4％。考虑到粒径对气体扩散规律的影响，采集的煤样的粒径小于0.25mm，提高了测量速度，反映了样品的安全性。气体含量的测定时间从36 h /件减少到3 h /件。此外，绝对误差为0.15–0.50 m³ / t，相对误差在5％以内。根据以上研究，提出了一种确定煤层瓦斯含量的新工程方法。