State Key Laboratory of Coal Mine Safety Technology, China Coal Technology & Engineering Group Shenyang Research Institute
State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization, Henan Polytechnic University
School of Safety Science and Engineering, Henan Polytechnic University

瓦斯扩散能力直接影响瓦斯资源开采、突出危险性、瓦斯涌出及含量测定。为了研究煤中瓦斯扩散系数受应力、瓦斯压力、温度等因素的作用规律，在稳定浓度差条件下对柱状煤进行了扩散系数测定，避免了通过解吸曲线反推扩散系数带来的模型依赖性问题。研究结果表明：无论是吸附性气体甲烷还是非吸附性气体氦气，扩散系数与有效应力近似为负线性关系，但相较于渗透率受影响较小；甲烷扩散系数随进气压力（浓度梯度）增大呈幂函数衰减规律，与温度关系满足阿伦尼乌斯公式。对比分析了稳态法实测扩散系数与经典模型和时变扩散系数模型所得扩散系数，发现所得扩散系数的量级相同，大小可相差数倍，且扩散系数随甲烷压力增大变化趋势不同。基于扩散系数受压力（浓度梯度）和温度影响规律，建立了变扩散系数扩散模型，并利用柱状煤实测的扩散系数对粒煤在恒温和变温条件下解吸数据进行了预测。对预测结果进行解吸试验验证，表明该模型无论是在恒温还是变温条件下都能很好反映煤基质中瓦斯扩散过程。

Gas diffusion ability directly affects gas exploitation, outburst risk, emission and content determination. In order to study the influence of stress, gas pressure and temperature on gas diffusion coefficient in coal, the gas diffusion coefficient in columnar coal sample was measured with stable concentration difference, which avoided the model dependence that caused by deducing diffusion coefficient through desorption curve. The experimental results shown that the diffusion coefficient was approximately negative linear related to the effective stress for both the adsorbed methane and the non-adsorbed helium, but it was less affected than the permeability. The methane diffusion coefficient decreased as a power function with increasing inlet pressure (concentration gradient), and the relationship with temperature satisfied the Arrhenius formula. The diffusion coefficient measured by the steady-state method was compared with those obtained by the classical model and the time-varying model. It was found that the obtained diffusion coefficients were of the same order of magnitude, the sizes can be several times different, and the variation trend of diffusion coefficient was different with increasing gas pressure. Based on the law of diffusion coefficient affected by pressure (concentration) and temperature, a variable diffusion coefficient model was established. The gas desorption for granular coal at constant and variable temperature was predicted utilizing measured diffusion coefficient for columnar coal, and the prediction results were validated by desorption test. It indicated that the model can well reflect the gas diffusion process in the coal matrix under both constant and variable temperature condition.

辽宁省自然科学基金资助项目（重点科技创新基地联合开放基金项目）（2021-KF-23-09）；国家自然科学基金资助项目（52074105，52174172）

秦玉金，安丰华，苏伟伟，等. 基于Fick定律的柱状煤瓦斯扩散系数变化规律及模型构建[J]. 煤炭科学技术，2023，51（8）：140−149

QIN Yujin，AN Fenghua，SU Weiwei，et al. Direct determination of the diffusion coefficient variation of coal based on Fick's law and model establishment[J]. Coal Science and Technology，2023，51（8）：140−149