煤屑暴露初期较长时间段瓦斯解吸规律的试验研究

Experimental study on the gas desorption regularity of the drill cutting during the long-lasting exposure of the initial stage

为了解决长钻孔取样暴露时间长、损失瓦斯量推算误差偏大的问题，采用自主研发的试验系统对煤屑暴露初期长时间段内的瓦斯解吸规律进行试验研究，找出了极限瓦斯解吸量与吸附平衡压力的关系，并对Qt=K√t和Qt=Q∞（1-e^λt＋A）两企理论公式在不同时间段内的拟合效果和损失量推算误差进行对比。结果表明，两公式在不同时间段内的拟合效果显著，决定系数均在0．94以上。从损失瓦斯量的推算误差来看，前者在30min内的推算误差较小，相对误差最大值小于7％，但随拟合时间段的向后推移，推算误差越来越大，最小值在40％以上；后者在30min内的推算误差较大，相对误差都在24％以上，而在30—70min和70～120min内的推算误差较小，相对误差都在11％以下。因此，前者适合煤样暴露短时间内损失瓦斯量的推算，后者则适用于暴露长时间后的损失瓦斯量推算，联合两个公式，按时间段推算损失瓦斯量，就可以减少长时间段内的计算误差。

The given paper is to introduce our experimental study on the coal-gas desorption regularity of the drilling cutting during the long-lasting exposure of the initial stage by using our self-developed soprtion/desnrption system. In order to resolve the current serious problem induced by long time exposure of coal samples in the initial stage in calculating the gas-loss, what we want to pursue is the gas desorption regularity in the intial stage exposure. The experiments we have done help us to make out the relationship between the maximum desorption amount and the desorption equilibrium pressure. The max- imum gas desorption amount, as a matter of fact, tends to increase with the increase of the pressure of the absorption equilibrium. And, therefore, we have also studied the fitting results with the two theory formulas, Qt=K√t and Qt=Q∞（1-e^λt＋A） , in different exposure periods and the gas loss calculation error. The results of our study have shown that the fitting results gained through the two theory for- mulae in different periods turn out to be well-fit with the related coef- ficients to the degree over 0.94. As for the loss calculation relative error, the maximum relative error turns out to be below 7 % by using the former formula in the first 30 min with the accuracy up to the minimum above 40% afterwards. However, the relative error using the latter formula in the first 30 min were 24% and dropped down to 11% in the periods of 30 - 70 min and 70 - 120 min. From the above results, it can be concluded that the former is suitable for the gas loss calculation in the short exposure period whereas the latter is suitable for the gas loss calculation in the longer exposure period. Thus, it can be inferred that it would be appropriate to choose one from the two ahernaitve formulae according to different exposure periods and it would be possible for us to work out the gas loss more accurately by reducing the relative error, thus making the gas desorption calculation more efficient. A comprehensive study can help us to testify the gen- eral applicability of our calculation method. If necessary, please refer to us for the experimental samples from Yiyuan coal mine, which de- serves your attention.