煤矿气体检测设备交叉干扰及评判方法研究

Research on cross interference and evaluation method of coal mine gas detection equipment

目前煤矿井下气体检测设备常因交叉干扰造成误报警甚至不报警,存在安全隐患,且现行国家或行业标准并未对气体交叉干扰提出明确的评判方法。针对上述问题,结合煤矿井下实际的环境气体类型和体积分数阈值情况,采用理论分析和试验验证相结合的方法研究了基于催化燃烧、激光和电化学3种常用原理的气体检测设备的交叉干扰机理和交叉干扰特性,设计并进行了交叉干扰试验。结合现行标准中气体检测设备误差试验通用方法,提出了基于煤矿井下特殊气体环境的气体检测设备交叉干扰评判方法:采用试验方法对气体检测设备交叉干扰特性进行评估,通入交叉干扰气样,计算气体检测设备的交叉干扰值,并与设备最高精度比较,从而判断非目标气体是否对气体检测设备造成交叉干扰影响。试验结果表明:气体检测设备交叉干扰影响普遍存在,在煤矿井下特定气体环境条件下,基于催化燃烧原理的甲烷检测设备易受硫化物和氢气干扰,应避免长时间在含有硫化氢或二氧化硫的气体环境中使用,以免造成催化剂中毒或抑制,影响测量精度;基于激光原理的甲烷和乙炔检测设备基本不受煤矿井下常见气体干扰,可以不进行交叉干扰试验,基于激光原理的乙烯检测设备易受甲烷气体的影响,经交叉干扰评判合格的,可以在甲烷环境中使用,不合格的应明确产品不能在含有甲烷的环境中使用;基于电化学原理的气体检测设备的交叉干扰特性具有不确定性,需经交叉干扰评判后,明确其可以和不可以使用的交叉干扰气体环境。

At present, coal mine underground gas detection equipment often causes false alarms or fails to alarm due to cross interference. There are potential safety hazards. There is no clear evaluation method for gas cross interference in current national or industry standards. In view of the above problems, combining with the actual underground environment gas type and volume fraction threshold in coal mines, the cross interference mechanism and characteristics of gas detection equipment based on the three commonly used principles of catalytic combustion, laser and electrochemistry are researched by using a combination method of theoretical analysis and experimental verification. The cross interference tests are designed and conducted. Combining with the common methods of gas detection equipment error testing in current standards, a gas detection equipment cross interference evaluation method based on the special gas environment in coal mines is proposed. The cross interference characteristics of the gas detection equipment are evaluated using the test method. By introducing cross interference gas samples, the cross interference value of the gas detection equipment is calculated. The value is compared with the highest precision of the equipment so as to determine if the non-target gas has a cross interference impact on the gas detection equipment. The test results show that cross interference of gas detection equipment is widespread. The methane detection equipment based on the catalytic combustion principle is easy to be interfered by sulfide and hydrogen under the specific gas environment conditions in the coal mine. Therefore,methane detection equipment should be avoided to be used in the gas environment containing hydrogen sulfide or sulfur dioxide for a long time. It will avoid poisoning or inhibiting the catalyst and affecting the measurement precision. Gas detection equipment based on the laser principle for detecting methane and acetylene is generally not affected by interference from common gases in coal mines and does not require cross interference testing.However, gas detection equipment based on the laser principle for detecting ethylene is affected by interference from methane gas. If it passes the cross interference evaluation, it can be used in a methane environment. If it fails, it should be clearly stated that the product cannot be used in environments containing methane. The cross interference characteristics of gas detection equipment based on the electrochemical principle are uncertain. It is necessary to determine the cross interference gas environment that can and cannot be used after the cross interference evaluation.