红外热像技术探测硫化矿石自燃火源的影响因素及其解决方法

Detection of Spontaneous Combustion of Sulfide Ores by Infrared Thermal Imaging Method

红外热像技术已成为火源探测的一种新方法,但其应用于井下自燃火源探测的实际操作中还存在许多不足。为了准确、快速地获取自燃矿石表面的温度场,初步探讨了发射率、感温距离、背景噪声、井下环境及热像仪稳定性等因素对探测结果的影响。通过试验,确定了硫化矿石表面的热发射率和使用IRI-1011热像仪探测系统测温时的合理距离。试验结果表明,硫化矿石表面的热发射率ε=0.88;常温下10m探测范围内,随着探测距离的增大,感温误差明显增大;热源温度一定时,3m、4m距离的感温误差几乎呈线性增大;热源温度T>50℃时,2m距离的感温误差趋于稳定。在试验基础上,采用数据拟合的方法,建立了热像仪感温与矿石表面实际温度间的定量关系。现场应用证明该研究结果实际可行。

Infrared thermal imaging technique is a new method for detecting the fire source. But a number of problems have to be solved before it can be applied to the detection of a spontaneous fire source of sulfide ores in mine. In order to determine the surface temperature of spontaneous combustion ores more accurately, preliminary studies were carried out on the effects of emission rate, the range of the detector, background noise, subsurface environment and stability of infrared thermal imagers. It is shown that the emission rate of materials and the range of the detector have greater influence on the precision of the measured temperature than other factors. Some measures are taken to control factors, such as background noise, subsurface environment and stability of infrared thermal imagers in order to avoid external disturbance and keep the imager stable. The emission rate of sulfide ores and the reasonable range of IRI-1101 infrared thermal imagers were determined based on experimental results and a theoretical analysis. The emission rate of sulfide ores is ε=0.88. Within 10m, the temperature error will increase greatly with the measuring distance. When the temperature of the heat source is kept in a certain range, the temperature error is almost linearly related with the distance at 3m and 4m. Temperature error is stable at 2m when the temperature of the heat source T〉50℃. The quantitative relationship between the temperature obtained by IRI-1101 infrared thermal imager and the real surface temperature of spontaneous combustion ores was established when distance is equal to 2m, 3m and 4m, respectively. After the adjustment, the relative error of four measuring points are -3.1%, 3.9%, 5.5% and -5.8%, respectively. The results of study were confirmed by field tests in the sulfide mine.