不同变质程度含瓦斯煤渗吸效应实验研究

发布时间：2018-04-24 14:19

本文选题：含瓦斯煤 + 渗吸效应　；参考：《河南理工大学》2016年博士论文

【摘要】：为研究水分单因素影响下含瓦斯煤渗吸效应的发生规律,在对目前相关实验装置调研的基础上,设计并搭建了一套用于渗吸效应研究的实验测试装置。该装置能够有效排除注水压力、注入水体积对实验的影响和干扰,确保煤样罐内瓦斯压力变化仅由渗吸效应促进含瓦斯煤解吸影响造成,同时配备高精度压力传感器,能够实现对渗吸效应过程中煤样罐内的压力变化进行全程监控与自动记录。通过考察型煤和颗粒煤在常压下的自发吸水效果,确定了合理的实验煤样型式为型煤;通过对型煤吸水不同时间后的吸水高度及含水率分布考察,确定了合理的实验用型煤高度和煤样含水率。在此基础上,针对无烟煤(WYM)、贫瘦煤(PSM)、焦煤(JM)和气煤(QM)等四种不同变质程度煤,分别开展了不同含水率和不同吸附平衡压力条件下的渗吸效应实验研究,探讨了不同变质程度煤渗吸效果对含水率和吸附平衡压力变化的响应特性;基于实验测试数据,对比分析了不同变质程度煤在相同实验条件下的渗吸效果差异,并对产生差异性的原因进行了理论分析。实验结果表明,水分自然进入含瓦斯煤后,煤样罐内瓦斯压力不断升高,说明水分能够依靠渗吸效应置换出处于吸附态的瓦斯,从而有效促进煤层吸附瓦斯解吸。吸附平衡压力相同时,随煤样含水率增长,渗吸瓦斯量和渗吸瓦斯率均逐渐增大,但前期增幅较大,后期增幅逐渐变缓;数据拟合结果表明,二者与煤样含水率之间均符合Langmuir型函数关系,当煤样含水率达到煤的极限吸水率时,渗吸瓦斯量和渗吸瓦斯率将达到极限值。煤样含水率相同时,渗吸瓦斯量随吸附平衡压力增长较好的符合Langmuir型函数关系,渗吸瓦斯率则随吸附平衡压力升高逐渐降低。不同实验条件下的渗吸瓦斯速度均经历“快速渗吸-缓慢渗吸-终止渗吸”三个发展阶段,且煤样含水率越高、初始吸附平衡压力越大,水分进入含瓦斯煤初期的渗吸瓦斯速度就越大。相同实验条件下,不同变质程度煤的渗吸效果存在较大差异:渗吸瓦斯量和渗吸瓦斯速度方面,均是WYM最大,QM和PSM居中,JM最小;渗吸瓦斯率方面,则是QM最大,WYM和JM居中,PSM最小。理论分析认为,不同变质程度煤的润湿性和孔隙结构特征不同是造成上述差异的根本原因。
[Abstract]:In order to study the occurrence rule of gas-bearing coal permeation effect under the influence of water single factor, a set of experimental test equipment was designed and built on the basis of investigation of relevant experimental devices. The device can effectively eliminate the water injection pressure and the influence and interference of the injected water volume on the experiment, and ensure that the change of gas pressure in the coal sample tank is only caused by the infiltration effect to promote the desorption effect of gas-bearing coal, and the high precision pressure sensor is equipped at the same time. The whole process monitoring and automatic recording of pressure change in coal sample tank can be realized. By investigating the spontaneous water absorption effect of briquette and granular coal under atmospheric pressure, the reasonable experimental coal type is determined as briquette, and the water absorption height and water content distribution of briquette after different time absorption are investigated. The reasonable height of briquette and moisture content of coal sample were determined. On the basis of this, four kinds of coal with different metamorphic degree, such as anthracite (WYM), lean coal (PSM), coking coal (JM) and gas coal (QM), were studied respectively under different moisture content and adsorption equilibrium pressure. The response characteristics of different metamorphic coal permeability to the change of moisture content and adsorption equilibrium pressure are discussed, and the difference of permeability and absorption effect of different metamorphic coal under the same experimental conditions is compared and analyzed based on the experimental data. The reason of the difference is analyzed theoretically. The experimental results show that the gas pressure in the coal tank increases continuously after the moisture naturally enters the gas-bearing coal, which indicates that the moisture can replace the gas in the adsorbed state by the effect of seepage and suction, thus effectively promoting the adsorption gas desorption in the coal seam. When the adsorption equilibrium pressure is the same, with the increase of moisture content of coal sample, the amount of gas absorption and the rate of gas absorption increase gradually, but the increase in the early stage is larger, and the increase in the latter stage is gradually slow. The data fitting results show that, The relationship between them and the moisture content of coal samples accords with the Langmuir function. When the water content of coal sample reaches the limit of water absorption rate of coal, the amount of gas permeation and the rate of gas absorption will reach the limit value. When the moisture content of coal sample is the same, the amount of gas permeating and absorbing gas with the increase of adsorption equilibrium pressure accords with the Langmuir function better, and the gas permeation rate decreases gradually with the increase of adsorption equilibrium pressure. Under different experimental conditions, the velocity of gas permeation and suction all go through three stages of development: rapid infiltration, slow permeation and stop infiltration. The higher the moisture content of coal sample is, the greater the initial adsorption equilibrium pressure is. The higher the gas absorption rate of water entering the gas-bearing coal at the initial stage. Under the same experimental conditions, there are great differences in the permeation effect of coal with different metamorphic degrees: in terms of gas permeation and gas absorption velocity, the WYM maximum QM and PSM are the lowest in the middle of JM, and the gas absorption rate is the lowest. The maximum QM WYM and JM are the smallest in PSM. The theoretical analysis shows that the difference of wettability and pore structure of coal with different metamorphic degree is the root cause of these differences.
【学位授予单位】：河南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TD712

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