Research Of Carbon Monoxide Gas Concentration Measurement System Based On Spectrum Absorption

In recent years, air pollution is more and more attention by people. It is more and more seriously to harm environment and people. Emissions detection is the foundation and the key of prevention and control of pollution in the production of industrial. But because most of the exhaust gas are poisonous and explosive, and the testing environment very bad, so gas detection system must achieve higher requirements. Therefore, the study of a modern measurement technology of high precision, high sensitivity, non-contact, stable and reliable have the important meaning to realize the measurement of carbon monoxide gas concentration.In this paper, the theory of gas molecules absorption is analyzed deeply. This paper introduces the fundamental laws of gas concentration measurement, analyzes linear and line width of absorption spectrum. And through the comparison of several absorption spectrum of carbon monoxide gas, selected1.568μm as the features absorption wavelength of carbon monoxide gas concentration measurement. Through the comparison of several gas concentration measurement methods based on spectrum absorption and the comparison of some module design scheme, selected design scheme of combined with wavelength modulation and harmonic detection. The scheme has higher precision and the detection sensitivity, safe and reliable, which can realize the online non-contact measurement.According to the design scheme, this article specifically designed photoelectric detection module circuit, including photoelectric detector drive circuit, current and voltage transformation circuit and signal amplifier circuit, and verified its good job characteristics by the experiments. For the overall design scheme, simulation model of the system is established, and finished simulink simulation analysis. Through the analysis of simulation results show that the rationality of the design scheme, and provide the basis for further product realization.