Online Monitoring Technology Of Flue Gas Emissions With DOAS

Presently, sulfur dioxide (SO2) and nitrogen oxides (NOX) are let from most of the boiler power plant to exceed forth the criterion about gas standard established by our government. Along with the improvement of environmental protection, it's necessary to monitor and control SO2 and NOX emission by taking some special measurement method.1. It is interested to measure the concentrations of SO2 and NOX in situ and on-line and useful to control air pollution. Some methods have been already developed, and commercial instruments are available. Author studied Differential Optical Absorption Spectroscopy (DOAS) for measuring SO2 and NOX.2. It is analyzed in detail what are the principle and those characteristic of the absorption spectrum of the gas molecule. By discussion for the light absorption law, the data processing methods of the main peak value method and differential optical absorption spectroscopy method (DOAS) are introduced. The technology is the key part of which are the experimentation method of the measurement and data processed with DOAS in monitoring the gas. According to the Lambert-Beer Law, to measure these component concentrations using the absorption spectrum of the smoke, in which is the absorption coefficient large.3. Design the experiment system to measure the smoke. The soft development of DOAS data processing system was accomplished based on the analysis to DOAS measurement process. Flue remote online monitoring system, which takes use of virtual instrument, can supervise the concentrations of sulfur dioxide and nitrogen oxide when recording and transmitting data remotely.4. Study the concentration of the SO2 and NO under some interferential factors. These experimentation results prove feasible and dependable of the system.