煤层气爆炸极限分析

煤层气爆炸极限的准确确定是煤层气安全开发利用的前提条件。煤层气爆炸极限不仅取决于单组分可燃性气体组成及其含量等自身因素,还受到大气压力、温度等因素的影响,因而首先对煤层气中单组分可燃性气体爆炸极限的准确确定十分必要。为此,采用按完全燃烧所需要的氧原子数和按化学计量浓度两种理论方法对煤层气中常见的单组分可燃性气体进行计算及分析。结果表明,两种理论方法对爆炸下限的计算比爆炸上限更好地接近实验值,其中按完全燃烧所需要氧原子数的改进方法更为准确。然后对含有多组分的煤层气,采用理查特利(Le Chatlier)公式法进行了理论计算,分析了惰性气体、压力、温度对爆炸极限的影响,与温度相比,压力对爆炸上限的影响更大。因此,在煤层气的开发利用中,应尽可能在低温和低压条件下操作。

Theoretical analysis on the explosion limit of coalbed methane gas

The accurate determination of the explosion limit of coalbed methane gas is the prerequisite for its exploitation and utilization. The explosion limit of coalbed methane gas depends not only on the composition of flammable gases and the percentage of each component, but on the atmospheric pressure, temperature, and other factors. Therefore, it is necessary to determine the explosion limit of each flammable gas in the coalbed methane gas. The combustibility of common single component in coalbed methane gas is calculated and analyzed by two theoretical methods: the number of oxygen atoms and the stoichiometric concentration needed for complete combustion, from which the calculated results show that the lower explosion limit (LEL) is much closer to the experimental values than the upper explosion limit (UEL); the former method is more accurate than the latter. For the coalbed methane gas with multiple components, a theoretical calculation is conducted by use of the Le Chatlier Formula to analyze the effect of inert gases, pressure and temperature on the explosion limits; pressure was found to have a greater effect on the UEL than temperature. As a result, we suggest that the exploitation and utilization of coalbed methane gas should be best under such conditions of low temperature and low pressure.