Experimental Investigation On Combustion Charactics Of Swirling Natural Gas Burner

As a premium fuel natural gas occupies more share in primary energy consumption structure of our country. There are many merits concerning the natural gas, including clean, large scale reserves, low combustion pollution,high economical efficiency compared with coal and oil. The pollutant caused by combustion can pollute our environment, though natural gas is clean energy.Therefore, clean combustion technology has got more and more attention by the researchers all over the world.Swirling gas burner is high efficient, and it is widely used in power plant.However, large quantities of nitrogen oxides can be released in case of fire. In order to improve the burnable efficiency and reduce the pollutant emission, it is necessary for us to develop a new lower NOx emission swirling gas burner.To meet the topic requirements of this paper, a new lower NOx emission swirling natural gas burner had been designed and manufactured.A new experiment rig had been built to measure the gas composition in different operating conditions. By means of analyzing database, the optimum conditions will be determined. And a planar laser induced fluorescence(PLIF) system had been built to measure the concentration of OH radicals during combustion process.This paper studies the combustion characteristics by experiment under different air distribution ratio, excess air coefficient, thermal load and different proportion of added CO2. The experimental results showed that 1:9 is the best air distribution ratio, and the fuel is fullest burning when excess air coefficient is up to 1.3. The experiment proves that the rake of stability flame and centre gas pipe are fully meet design requirements. It can be seen from the experimental results that the emission amount of NO first increases and then decreases with the increasing of CO2 in CH4 or air.Then, the OH radicals during combustion process were measured by OH-PLIF technology under different air distribution ratio, excess air coefficient and different proportion of added CO2. The experiment proved that the radiation fluorescence of OH radical in flame is brightest when the excess air coefficient is up to 1.3. The concentration of OH radical in flame has a maximum value when the air distribution ratio is 1:9. The position of the flame front is higher and higher with the increasing of CO2 in CH4 or air. And the radiation intensity of OH radical during combustion process first reduces and then increases and finally began to reduces again with the increasing of CO2 in CH4. However, it first increases and then reduceswhen CO2 mix with air.