恒定电场作用下瓦斯吸附量临界值的理论研究

发布时间：2018-07-01 14:06

本文选题：恒定电场 + 焦耳热效应　；参考：《太原理工大学》2015年硕士论文

【摘要】：通过外加作用场来影响瓦斯的开采方法是一种较为新颖的开采模式，且能为瓦斯的开采工作提供一种安全保障，但仍然需要进一步的研究和探讨。本文通过考察外加恒定电场对瓦斯吸附作用的影响，对瓦斯的吸附量临界值进行了理论分析与推导，并得出了具体表达关系式。通过考察可知，煤属于非晶态类的固体电介质，是一种典型的电介质材料，且导电能力是其特性之一。将煤与瓦斯系统置于恒定电场中，，会使煤的导电性增强，并会在系统内部产生焦耳热效应和极化效应。将煤与瓦斯系统置于恒定电场中，一方面会由于发生焦耳热效应而引起系统温度升高，从而促使系统中瓦斯气体的解吸；另一方面，由于恒定电场的作用，会导致煤体表面吸附势阱深度的加深，进而会使瓦斯的吸附量增加。由于这两者共同作用于系统，因此最终的吸附量变化是由这两者共同竞争的关系所决定的，当由于吸附势阱深度的增加起主导作用时，瓦斯吸附量会随着电场电压的升高而增加；而当由于引发的焦耳热效应所导致的系统温度升高成为主要因素时，瓦斯吸附量则会随着电场电压的升高而减少。最终的结果是瓦斯吸附量随恒定电场电压升高的变化趋势是一种“类抛物线型”先升高后降低的变化，因而在变化过程中会出现一个临界值点，在此临界电压处瓦斯吸附量会达到最大值。本文分为三部分对吸附量临界值进行推导。第一：首先通过对由焦耳热效应引起的温度升高量与瓦斯吸附量的关系进行分析，然后进行关系转换得出温度升高作为主导因素时瓦斯吸附量与电场电压的理论关系式；第二：对煤表面势阱深度加深作为关键因素的情况进行分析，确定煤体瓦斯吸附量与电场电压之间的理论关系式；第三：对两种情况下的瓦斯吸附量与电场电压的关系式进行拟合，最终得出总的吸附量与电场电压的理论关系式。本文在得出恒定电场作用下瓦斯吸附量与电场电压的理论关系式后，利用相关实验数据对结果进行了分析论证，证明了恒定电场中吸附量临界值确实存在，为将来恒定电场中瓦斯吸附规律的研究提供了一种思路。
[Abstract]:It is a new mining mode to influence the gas mining method by applying the action field, and it can provide a kind of safety guarantee for the gas mining work, but it still needs further research and discussion. In this paper, the influence of applied constant electric field on gas adsorption is investigated, the critical value of gas adsorption is theoretically analyzed and deduced, and the concrete expression formula is obtained. According to the investigation, coal belongs to amorphous solid dielectric, which is a typical dielectric material, and its conductivity is one of its characteristics. When the coal and gas systems are placed in a constant electric field, the conductivity of coal will be enhanced, and the Joule heat effect and polarization effect will be produced in the system. Placing coal and gas systems in a constant electric field will, on the one hand, cause the temperature of the system to rise because of the Joule heat effect, thus prompting the gas desorption in the system; on the other hand, because of the effect of the constant electric field, It will lead to the depth of adsorption potential well on the surface of coal, which will increase the amount of gas adsorption. Because the two act on the system together, the ultimate adsorption capacity change is determined by the competing relationship between the two, when the increase in the depth of the adsorption potential well plays a leading role, The amount of gas adsorption will increase with the increase of electric field voltage, but when the temperature of the system caused by Joule heat effect is the main factor, the amount of gas adsorption will decrease with the increase of electric field voltage. The final result is that the change trend of gas adsorption capacity with constant electric field voltage is a kind of "parabola" which rises first and then decreases, so there will be a critical point in the process of change. At this critical voltage, the gas adsorption capacity will reach the maximum value. This paper is divided into three parts to deduce the critical value of adsorption quantity. First, through the analysis of the relationship between the temperature rise caused by Joule heat effect and the gas adsorption capacity, the theoretical relationship between the gas adsorption capacity and the electric field voltage is obtained when the temperature rise is the dominant factor. Second, the paper analyzes the situation that the depth of coal surface potential well deepens as the key factor, and determines the theoretical relation between coal gas adsorption quantity and electric field voltage. Thirdly, the relationship between the gas adsorption capacity and the electric field voltage is fitted, and the theoretical relationship between the total adsorption capacity and the electric field voltage is obtained. In this paper, the theoretical relationship between gas adsorption capacity and electric field voltage under the action of constant electric field is obtained, and the results are analyzed and proved by using relevant experimental data, and it is proved that the critical value of adsorption quantity in constant electric field does exist. It provides a way to study the law of gas adsorption in a constant electric field in the future.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD712

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