Abstract:
The gases in underground coal mines are composed of multiple components characterized by necessity,disaster triggering and early warning.The quantitative measurement of coal mine gases is of significance for the early identification of hazardous sources,the accurate warning of relevant secondary disasters,and scientific decision making for emergency rescue.Firstly,the principles and research progress of commonly used gas analysis techniques are presented,i.e.,gas sensors (catalytic combustion type,thermal conductivity type,optical interference type and electrochemical type),chromatographic analysis technology,Fourier transform infrared spectroscopy,non dispersive infrared spectroscopy and tunable diode laser absorption spectroscopy.The field application of the above mentioned gas detection technologies is summarized.Secondly,the extreme working conditions in coal mines including large atmospheric pressure and temperature variation,high relative humidity and dust concentration,as well as strong electromagnetic interference are pointed out.The technical applicability of different detection technologies is also compared from the aspects of applicable gas,pros and cons,application fields,and representative instruments.Then,on the basis of cross interference analysis,some suggestions for single gas detection (such as CH4,O2,CO,C2H4,C2H2 and H2) and multi component gas mixture online monitoring as well as in situ analysis of toxic gases in explosive environments during emergency rescue are put forward.When selecting a detection method under the premise of measurement accuracy and range,some comprehensive considerations should be given to cost performance,background interference,and zero drift.Finally,the bottleneck problems such as the low detection limit of trace gas,cross interference of multi component gas mixture,high cost of specific wavelength laser and high performance detector are presented,which shows the research direction for realizing the in situ quantitative analysis and dynamic monitoring of coal mine gas.