新扩散模型下温度对煤粒瓦斯动态扩散系数的影响

发布时间：2018-07-12 18:32

本文选题：瓦斯 + 扩散模型　；参考：《煤炭学报》2015年05期

【摘要】：升温促进煤基质中瓦斯快速大幅解吸/扩散是热激励法增产瓦斯机理之一,其首要关键科学问题是探明温度对扩散系数的影响规律和影响机理。采用恒温与升温方法进行了3种不同条件下的扩散实验:(1)初始同压不同温吸附后恒温扩散;(2)同初始吸附量条件下(高温高压、低温低压吸附后)恒温扩散;(3)同初始温压吸附后的升温扩散实验。实验结果表明:实验(1),(2)中用单孔隙经典扩散模型计算的常扩散系数随温度升高呈现无规律的波动形态,经典模型无法解释这一现象。原因是经典模型不能精确描述全时段扩散过程,误差极大,继而发现了扩散系数随时间延长而衰减的特有现象。为此,提出了能精确描述全时扩散过程的动态扩散系数新模型。新模型分析表明,煤基质中多尺度非均质孔隙形态决定了多级孔隙扩散系数分布,进而导致了扩散系数随时间延长而衰减。新模型下动扩散系数随温度升高单调递增,符合阿雷尼乌斯关系,规律惟一,经典模型常扩散系数是新模型动态扩散系数的平均值。新模型涵盖了经典模型,前者是后者的推广。
[Abstract]:The rapid desorption / diffusion of gas in coal matrix by heating is one of the mechanisms of increasing gas production by thermal stimulation. The most important scientific problem is to find out the influence law and mechanism of temperature on diffusion coefficient. The diffusion experiments under three different conditions were carried out by using the method of constant temperature and temperature rise: (1) diffusion at constant temperature after adsorption at different initial temperature, (2) at the same initial adsorption amount (high temperature and high pressure), (3) the temperature diffusion experiment after the initial temperature and pressure adsorption. The experimental results show that the constant diffusion coefficient calculated by the single pore classical diffusion model in experiment (1), (2) shows an irregular fluctuation with the increase of temperature, which cannot be explained by the classical model. The reason is that the classical model can not accurately describe the diffusion process in the whole time period, and the error is very great, and then we find that the diffusion coefficient decays with time. Therefore, a new dynamic diffusion coefficient model which can accurately describe the full-time diffusion process is proposed. The new model analysis shows that the multi-scale heterogeneous pore morphology in the coal matrix determines the distribution of the multistage pore diffusion coefficient, which leads to the attenuation of the diffusion coefficient with time. Under the new model, the dynamic diffusion coefficient increases monotonously with the increase of temperature and accords with the Arenius relation. The law is unique. The constant diffusion coefficient of the classical model is the average value of the dynamic diffusion coefficient of the new model. The new model covers the classical model, the former is a generalization of the latter.
【作者单位】：河南理工大学河南省瓦斯地质与瓦斯治理重点实验室-省部共建国家重点实验室培育基地;重庆大学煤矿灾害动力学与控制国家重点实验室;河南理工大学中原经济区煤层(页岩)气河南省协同创新中心;
【基金】：国家自然科学基金资助项目(51004041) 长江学者和创新团队发展计划资助项目(PCSIRT1235) 煤矿灾害动力学与控制国家重点实验室开放课题资助项目(2011DA105287-KF201313)
【分类号】：TD712

【参考文献】