煤层瓦斯含量井下一站式自动化精准测定方法

Method of underground integrated automatic and accurate determination ofcoalbed gas content

煤层瓦斯含量是预测煤与瓦斯突出危险性和评价矿井瓦斯储量的基础参数。针对现有测定方法需要井上和井下分阶段测量、测定周期长的不足,提出了煤层瓦斯含量井下一站式自动化测定新方法,介绍了煤样井下直接破碎系统、瓦斯解吸量自动化计量系统和数据自动采集处理系统等关键单元构成及主要技术指标。其次,针对现有测定方法中损失瓦斯量估算误差大的难题,考虑煤孔隙结构的非均匀性建立了瓦斯分数阶扩散模型,以此准确推算煤样暴露过程的损失瓦斯量;搭建了模拟井下煤层瓦斯含量测定流程的误差分析系统,通过设定不同吸附平衡压力来改变瓦斯含量,设定不同暴露时间来改变损失瓦斯量,并通过与传统模型对比来验证分数阶模型的准确性。实验表明,分数阶模型推算损失瓦斯量的误差在10%以内,测定瓦斯含量的误差在5%以内,而传统■模型和幂函数模型测定瓦斯含量的误差达到20%以上。最后,基于煤层瓦斯含量井下一站式自动化测定方法,研发了CWH12型煤层瓦斯含量测定仪,在淮南矿区朱集东矿和潘三矿进行了现场应用,并使用煤矿原有瓦斯含量测定设备对同一地点、同一深度的煤样进行了测定比较。现场试验表明,CWH12型煤层瓦斯含量测定仪比原有设备的测定值平均提高了13.5%,测量时间缩短至1.5 h以内,实现了煤层瓦斯含量的快速精准测定。

Coalbed gas content is one of the basic parameter for predicting the risk of coal and gas outburst and evaluating mine gas reserve.In view of the shortcomings that the existing methods need to determine the gas content with the measurements at surface and underground and are time-consuming,an underground integrated method for determining coalbed gas content is proposed.The composition and main technical indexes of key units such as coal sample underground direct crushing system,gas desorption automatic measurement system and data automatic collection and processing system are introduced.In terms of the large estimation error of gas loss in the existing methods and considering the heterogeneity of coal pore structure,a gas fractional diffusion model is established to accurately calculate the gas loss during coal exposure.An error analysis system simulating the underground coalbed gas content determination is established.The gas content is changed by setting different adsorption equilibrium pressures and different exposure times.The accuracy of the fractional model is verified by comparing it with the traditional model.The experiment shows that the error of calculating gas loss by fractional model is less than 10%,and the error of measuring gas content is less than 5%,while the error of measuring gas content by traditional model and power function model is more than 20%.Finally,based on underground integrated method of determining coalbed gas content,the CWH12 coalbed gas content meter is invented and applied in the Zhujidong and Pansan coal mines in the Huainan mining area.The traditional measurement equipment is used to measure gas content and compare with CWH12 for the coal samples at the same location and depth.The field test shows that compared with the original equipment,the measurement values of CWH12 is improved by 13.5%on average,and the measurement time is shortened to less than 1.5 h,realizing the rapid and accurate determination of coalbed gas content.