【作者】 马东民；

【导师】 黄庆享；

【作者基本信息】 西安科技大学 ， 矿业工程， 2008， 博士

【摘要】 煤层气在煤基吸附剂上的解吸机理是当前煤层气开采面临的核心问题之一。鉴于当前国内外对解吸作用理论研究的缺乏,确定论文研究内容:(1)通过当前吸附设备的调研,设计、制造、检验、使用大样量煤层气吸附解吸仿真实验仪;(2)通过大样量煤层气吸附解吸实验,获得我国主要的煤层气勘探开发地区煤的吸附解吸数据;(3)对实验数据进行数学分析、拟合,归纳可信度较高的吸附解吸数学模型;(4)对吸附质、吸附剂及其界面特征进行分析,利用物理化学的基础理论,推导可以反映煤层气吸附解吸过程的数学模型。对建立的数学模型进行检验分析,对模型中的参数进行分析、物理意义核定。研究结论:(1)煤层气的解吸过程与吸附过程不可逆。(2)煤层气的吸附曲线、解吸曲线皆为Brunauer吸附等温线的Ⅰ型。利用SPSS对实验数据拟合较好(R2≥0.9)的数学式有Langmuir方程、指数函数、对数函数、Weibull函数,其中Weibull函数拟合的可信度最高(R2≥0.99),相对误差较小(Δ<0.5%)。(3)以Lenard-Jones介质表面势函数分布分析入手,引入覆盖度θ函数。确立多孔型固体吸附剂(煤)与吸附质(CH4)的作用强度由半孔宽度r决定,煤的表面能量分布非对称,服从Weibull函数,推导获得吸附、解吸作用的数学模型:V = V0 ?[1?exp(?bPq)]。(4)根据引起Weibull函数模型中吸附焓(b)的变化因素,将解吸作用进行初步分类:降压解吸、置换解吸、扩散解吸、升温解吸、电磁场诱发解吸等。(5)确立煤层气的解吸量与吸附量无关。煤层气的解吸量与压力关系可用相应的数学表达式描述;(6)对煤层气采收率进行分析后认为:煤层气的采收率仅与解吸过程的吸附热有关,与其他因素无关。更多还原

【Abstract】 The desorption mechanism of Coal bed methane (CBM) in coal-based adsorbents is one of the critical problems in today’s exploitation of CBM. In view of the lack of theoretical research on desorption home and abroad, the research includes the following several main aspects:1. Based on a survey of the available adsorption equipment, a simulated super-weight equipment of adsorption and desorption is designed, manufactured, tested and used;2. Through super-weight experiments on absorption and desorption of CBM, data of absorption and desorption of the coal in the major CBM exploitation areas in our country are collected;3. Through mathematical analysis,and the fitting of the experimental data, reliable mathematical models of absorption and desorption are derived;4. Through the analysis of adsorbate, sorbent and their interface features, mathematical models reflecting the process of the adsorption and desorption of CBM are derived, using the fundamental theories of physical chemistry, and the established models are checked, the parameters are analyzed and confirmed in terms of physical significance.Conclusions:1. The processes of adsorption and desorption of CBM are irreversible. The process of desorption lags behind that of adsorption;2. The adsorption and desorption curves of CBM are all of ModelⅠof Brunauer adsorption isotherm. The mathematical expressions that fit well into the experimental results(R2≥0.9) include Langmuir equation, exponential function, logarithmic function,and Weibull function, among which Weibull function is of the highest fitting degree(R2≥0.99)with the smallest relative error (Δ<0.5%); 3. Based on the analysis of the Lenard-Jones potential function of medium surface and the use of coverageθfunction, it is established that the intensity of the porous solid sorbent(coal) and the adsorbate(CH4) is determined by the scale of molecules (The width of half pore is r),and that the surface energy distribution of coal, in agreement with Weibull function, is unsymmetrical, thus the mathematical models of adsorption and desorption are derived: V = V0 ?[1?exp(?bPq)] V0 = the largest adsorption amount b= change of adsorption heat q= the unsymmetry of pores4. According to the change factors of adsorption enthalpy (b)in Weibull function model, the desorption is classified into decompression desorption, metathesis desorption, pervasion desorption, heating-up desorption and electromagnetically induced desorption, etc.;5. It is confirmed that desorption amount and adsorption amount of CBM are not interrelated. The relation between desorption amount and pressure can be formulated by mathematical expressions;6. Based on the analysis of the CBM exploitation rate, it is concluded that the rate is solely determined by adsorption heat in desorption process.更多还原