The Catalytic Combustion Type Methane Concentration Detector With Anti-poisoning Function

Coal mine gas accident is the frequent accident that taking place in the mine.And the most frequently occurrence of gas accident is the gas explosion, leading to pay a high price for it in economy and life safety. With the rising demand for coal, the mining depth needs to be deepened, and the environment of the mine is more complicated, there are a lot of H₂S that can make the catalytic sensor inactive, causing the overwhelming measurement error. Thus, we studied a detection method of anti- poisoning that has a realistic significance to detect the concentration of methane in a high sulfur mine.The design has researched on catalytic sensor working principle carefully,analyzed the poisoning mechanism deeply, and then finds out the main reason for poisoning. By exploring the poisoning mechanism, finding that the main reason for sensor poisoning is catalyst deactivation, catalyst deactivation due to catalyst reacts with H₂S form sulfates. Since sulfates can be decomposed at a certain high temperature, so the paper presents a methane detecting method with anti-poisoning function, that is, after a certain time raising the sensitive components temperature, so that sensitive components is disinfected in the shortest possible time（thermal decomposition of sulfates） to restore the activity of the sensitive components. The paper proposes a thermostatic control circuit which can precisely control the sensor operating temperature to finish disinfection process effectively and protect the sensitive components. In order to facilitate migration and check, the hardware and software of detector are modular design. The hardware circuit of detector consists of the following section: MCU system, infrared control decoding circuit, display and alarm circuit, power circuit,thermostatic control circuit, signal conditioning circuits, frequency output andconnection detection circuit. The software part consists of the following section:the main program, infrared control decoding program, the calibration program,concentration data handler program, disinfection program, concentration output program.The paper finished the performance test and error analysis for the catalytic combustion methane concentration detector which having an anti-poisoning function, and finished the stability and anti-poisoning ability testing respectively.The detector has good anti-poisoning performance, so that it is suitable for use under high-sulfur coal mines.