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一、解吸法损失瓦斯量原计算方法及缺陷 目前,在煤田地质勘探工作中,普遍采用解吸法来测定煤芯中的瓦斯含量。解吸法的关键,是以在地面解吸得出的瓦斯释放规律来推算煤芯在解吸前暴露时间内的损失瓦斯量。 煤芯在提升过程中,当瓦斯气压大于孔内静水压力时开始释放瓦斯。但是,瓦斯压力是个未知数,无从知道何时开始释放瓦斯。因而假定:煤芯提升到孔口时间的一半(t_1/2)作为煤样在孔内暴露时间。即认为从这个时刻开始,煤芯释放瓦斯等同于在地面的解吸状态。 煤样解吸前暴露时间包括孔内暴露时间(t_1/2)和装入密封罐时间(t_2),令θ=(t_1+t_2)/2。解吸时间为t_3。目前仍然承认并使用上述假定。
First, the desorption method to calculate the original loss of gas and defect calculation At present, coal geological exploration work, commonly used desorption method to determine the gas content in the coal core. The key of the desorption method is to calculate the amount of gas lost during the exposure time of the coal core before desorption based on the law of gas release obtained from desorption on the ground. Coal core in the process of lifting, when the gas pressure is greater than the hole hydrostatic pressure began to release gas. However, the gas pressure is unknown, no way to know when to start releasing gas. Therefore, it is assumed that half of the coal core lift time to the orifice (t 1/2) is used as the time during which the coal sample is exposed in the pores. That is, from this moment on, the coal core releases methane equivalent to desorption on the ground. The pre-desorption time of coal sample includes the time of exposure (t_1 / 2) and the time of filling the can (t_2) so that θ = (t_1 + t_2) / 2. Desorption time is t_3. The above assumptions are still acknowledged and used.