Research On On-line Detection System Of SO₂ Concentration In Power Plant Flue Gas

In recent years, with the rapid development of modern industry in China, the use of coalhave been increasing year by year. China is almost the only economic power country in theworld which uses coal as the primary energy. In China, power industry consumes a lot of coalvery year, more than 40% total volume of coal used in our country. A considerable period oftime in the future, thermal power is still dominated in our country's power. It is predicted thatNational generating capacity will reach 40 billion kWh and about 80 billion kWh by2010 and2015.When coal is burning ,it releases a lot of sulfur dioxide into the atmosphere.The pollution of sulfur dioxide has some characteristics such as low concentrations,large-scale and long-term effect. And the harm is chronic, progressive and accumulated.Sulfur dioxide is a major producer of acid rain pollution, the main pollutants of atmospheric,and it has caused serious harm to human beings and the natural environment.This paper mainly designed the detection system of the concentration of sulfur dioxide inpower plant flue gas by UVabsorption spectrometry. Details are as follows:(1) This paper systematicly summarizes the hazards of sulfur dioxide in the atmosphere,and the various methods of detection on sulfur dioxide in current domestic and international.Through analysis and comparison, the UV absorption method to on-line detect theconcentration of sulfur dioxide in power plant flue gas was chosen.(2) This paper introduces the principle of the detection of sulfur dioxide concentration byUV absorption, the characteristic of UV radiation when it transports in the air, as well as theimpact of temperature and pressure on sulfur dioxide to absorb ultraviolet light. Themathematical models of sulfur dioxide concentration were established, which was detected byUVabsorption in the power plant flue gas .(3) This paper introduces the variety of UV sources which can be used to detect the sulfur dioxide, the variety methods of light source collimation, the method of wave filter inoptical system and all kinds of the reception equipments which can be used in UV detectionnowadays. Avariety of devices were selected through analysis and comparison. Some circuitsof detection system have been designed, including light source driver circuit, wave filtercircuit, amplification circuit and rectifier circuit. The entire detection system has beendesigned in this paper, including a gas chamber was designed and the optical detection system,gas system, and signal processing system were established.(4) Some experiments have been done with the combination of this detection system andthe mathematical models of sulfur dioxide concentration. Through analysis the experimentaldata, it is proved that the on-line sulfur dioxide concentration detection system which we havedesigned in power plants flue gas can accurately determine the concentration of sulfur dioxidein flue gas.