基于TDLAS技术的井下多组分气体浓度监测(特邀)

Monitoring of Multi-component Gas Concentration in Coal Mine Based on TDLAS Technology(Invited)

采用可调谐半导体激光吸收光谱技术分析了气体浓度与谐波强度之间的关系,并设计了多组分气体长距离输送系统对矿山有害气体进行远程实时监控,实现千米外对矿井环境内多种气体的实时浓度监测。在理论推导的基础上,对矿井中可能出现的一氧化碳气体(CO)、二氧化碳气体(CO_(2))、甲烷气体(CH_4)和乙烯气体(C_(2)H_4)四种气体进行了标定,获得了浓度标定曲线及检测下限,检测下限均可达到10^(-4)以下。对甲烷气体标定得到的线性相关系数R达到0.99554,检测下限为2.2×10^(-6),探测的稳定度为0.137%。在矿井应用中,长时间监测结果与矿方所拥有的气体检测系统检测到的数据变化趋势一致,随机抽取样本与第三方检测结果误差在5%以内。该多组分气体监测系统具有准确度高、监测限低和稳定性好等优点,可为矿山气体安全提供可靠的数据支持。

Coal is the most important energy mineral in China,and methane gas is the main harmful gas in the mine production process,which may causes miners to be poisoned and even causes major safety accidents such as fire and gas explosion,which seriously threatens the life safety of coal miners and affects the mining progress.In order to prevent the occurrence of safety accidents caused by hazardous gases,the real-time monitoring of harmful gases in the mine is an important measurement to ensure the safety of mine production.Only by monitoring and detecting the concentrations of these harmful gases in a timely and accurate manner can problems be found early and corresponding measures taken.At present,as a new type of high-sensitivity,high-resolution,anti-electromagnetic interference sensor,tunable diode laser is widely used in various fields,and is an effective means to detect gases.In this paper,the Tunable Diode Laser Absorption Spectroscopy(TDLAS)is used.Based on the Lambert-Beale law,the relationship between gas concentration and signal intensity is analyzed.Based on TDLAS,a multi-component gas long-distance sensing system was designed to carry out remote real-time monitoring of harmful gases in the mine,so as to realize the real-time concentration monitoring of multiple gases in the mine environment from kilometers away.In this paper,four gases that may occur in the mine were calibrated,namely carbon monoxide gas(CO),carbon dioxide gas(CO_(2)),methane gas(CH_4)and ethylene gas(C_(2)H_4).The calibration curves of the four gases and lower detection limits were obtained.The coefficients of determination R~2 were all greater than 0.99,indicating that the linear fittings were accurate.The lower detection limit for each gas can be less than 0.01%.Especially for methane gas,the main component of harmful gas,the calibrated linear correlation coefficient R reaches 0.99554,and the detection limit is as lower as 2.2×10^(-6).The stability of the measurement is 0.137%.For the remaining three selected gases,the carbon monoxide gas reached the lower detection limit of 27.1×10^(-6),and the stability of the measurement was 0.402%;the carbon dioxide gas reached the lower detection limit of 23.2×10^(-6),and the stabilityof the measurement was 0.365%.The ethylene gas reached the lower detection limit of 80.7×10^(-6),and the stabilityof the measurement was 0.291%.After the calibration in lab,the gas detection equipment was applied in coal mine.The long-term monitoring results are consistent with the the gas detection system owned by the mine.By random sampling of the gases,detection results are compared with the third-party test results and the difference between the two is within 5%.The multi-component gas monitoring system has the advantages of high accuracy,low monitoring limit and good stability,which can provide reliable data support for mine gas safety and has a promising application in the mining industry.