Research And Application Of Flue Gas Monitoring System Based On Differential Spectroscopy

With the development of China’s industrial and the progress of science & technology, the problem of environment has become increasingly serious. Under this background, the voice of the community on environmental protection getting more and more intense. Sustainable development has become the theme of development for a long period of time. Real-time monitoring of gaseous pollutants for corporate emissions is a priority and an important prerequisite to control air pollution. Traditional non-dispersive infrared（Non Dispersive Infrared, Acronym NDIR） technology, has unavoidable disadvantage for cost and measuring low concentrations, under this background, this article in-depth study on DOAS（Differential Optical Absorption Spectroscopy, Acronym DOAS） technology, and apply it to the flue gas monitoring, this article’s main research is:1.Embarked on the current major pollutants SO₂, NOX, presentation and analysis of the current common flue gas monitoring methods and principles, according to Lambert- Beer law（Lambert- Beer）, focuses on research DOAS principle of the method, and the method of least squares algorithm, lets calculation results are closer to the real value.2.Based on the spectral characteristics of SO₂, NOX, the proposed design method based on the flue gas DOAS Continuous Emission Monitoring System（Continuous Emission Monitoring System, referred to CEMS）, and the detailed study of the four major sub-systems- gaseous pollutants monitoring subsystem, particulate matter monitoring subsystem, flue gas parameters subsystems, data processing and transmission subsystem.3. Study on the key technology of the whole CEMS system, specific include: the system temperature, pressure, flow rate, oxygen content, humidity and dust concentration measurement of the relevant parameters of the study, and design the entire system of gas and electrical control system.4. Conducted three test using CEMS system with DOAS method, the first is the single standard gas test, the second is the mixed standard gas test, the third is the actual site of flue gas test. The test results using statistical methods to analyze and verify the DOAS method can be applied to the actual flue gas monitoring. The focus of this article is the practical application of DOAS method. Through the application of comparative test and case study, it proved that the DOAS method has a very broad prospect in flue gas monitoring.