Design And Realization Of Methane Detection Based On Catalytic Combustion

This paper introduces firstly situation of coal mine safety and the importance of mining. The greatest disaster in coal mine is gas disaster, and main performance of the disaster is gas explosion.Methane is analyzed by thermocatalysis sensor in Coal Mines in our country at Present. With zero drift and nonlinear in the output signals, zero adjustment and sensitivity correction system of methane sensors is needed frequently. Methane sensors always have the problems of short service life ,bad stability and short-period. The more gas concentration is,the more non-linear thermocatalysis sensors. Methane sensor's linearity fitting and nonlinear fitting are presented. After analysis and comparison, the piecewise interpolation is used to do nonlinear data processing. Stable zero is the most important affection factor of measurement accuracy. Zero self adjustment is processed by storing zero-value.Based on auto-calibration technology of mine methane sensor and bussing technique, improvements are made in conventional measurement circuit and method of detection. Based on this,a new kind of design scheme of sensing system for thermocatalysis sensors is introduced.MCU is chosen as the microprocessor. Among them ,the control system of hardware has introduced the peripheral circuit including main chip, circuit of power supply ,module of the signal gathers ,alarm circuit and communication circuit. Gas satety concentration,zero drift and nonlinear coefficient are stored with the application of external memory EEPROM.With serial devices in place of parallel devices, we can save resources of MCU's I/O and increase the functions of MCU. The paper makes a lot of researches on communication technology. After the research on the comparison of communication technologies, the data transmits between the sensors and underground monitoring outstations through RS485 bus. The sensor sends gas concentration to underground monitoring outstations for real time monitoring of methane.The modular programming approach is adopted on the software design and code is writed in C51 language. Software programming has been done to realize these functions of subprogram in detail. The technological flowsheets are drawn more visually.After software and hardware of system are designed, the experiments are designed. I made a series of simulated tests under the background of non-test in field. Verification test of each functional module is carried,then the whole systems do .