水分润湿过程中煤中瓦斯解吸规律试验

为了深入探讨水分对煤中瓦斯解吸特性的影响,采用试验和理论分析相结合的方法,按照原煤的固有粒度配比加工制作型煤,充分干燥后使其吸附平衡以模拟原始煤体,然后利用自制的试验装置实现水分自然进入含瓦斯煤,再测试水分润湿含瓦斯煤过程中样品缸内的瓦斯压力变化情况。结果表明:水分润湿含瓦斯煤过程中样品缸内瓦斯压力不断升高,水分能置换出煤中吸附瓦斯;相同吸附平衡压力下,煤样含水率越高,水分占据的有效吸附位越多,累计瓦斯解吸量越大,当煤样含水率达到煤的极限吸水率时,累计瓦斯解吸量达到极限值;同一含水率条件下,随吸附平衡压力增长,煤样吸附饱和度逐渐增加,水分越难进入煤体内部细微孔隙,造成累计瓦斯解吸量逐渐增加,但增幅逐渐减小,随吸附平衡压力不断升高,极限瓦斯解吸量趋于一定值。

Experimental study for the coal gas desorption regularity in the process of moistening

The paper is aimed at presenting the results of its experimental study for the coal gas desorption regularity in the process of moistening and the influence of moisture on the coal gas desorption features in an integrated method of laboratory experiments and theoretical analysis.To be exact,our experiments have been done in the following procedures:First of all,we have prepared the sampling coal briquettes,which are characteristic with the same particle size and proportion with the original coal blocks.And,then,the coal briquettes could be put into a sampiing tank and pre-dried so as for them to reach a certain equilibrium pressure for simulating the raw coal status in-situ.And,thirdly,by using a self-made experimental platform,we have sprayed some water into the coal containing natural gas.Later,the gas pressure change has been observed and monitored during the wetting process.The experimental results we have gained show that the gas pressure in the sampling tank tends to increase continuously in the wetting process,which symbolizes that the moisture can displace the adsorbed gas in the coal and help to improve the gas desorption rate.Under the same adsorption pressure,the higher the moisture percentage is,the more effective adsorption sites the moisture would try to take,and the greater the cumulative gas desorption amount would become.Therefore,it can be concluded that the increase of the cumulative quantity of gas dcsorbed with the moisture percentages tends to fit the function of Langmuir model.And the cumulative gas desorption quantity tends to reach its maximum limit when the water content expands and propagates into the maximum quantity of the water adsorption of the coal.Under the same moisture condition,the adsorption saturation of the coal sample increases gradually with the increase of the adsorption equilibrium pressure,which makes it more difficult for the moisture to enter the micro pores in the coal sample.In such a situation,the cumulative amount of gas desorption tends to increase but the growing rate tends to decrease gradually,which also fits the function of Langmuir model.Thus,in turn,the gas desorption tends to reach its maximal limit with the increase of the adsorption equilibrium pressure.