N₂O Emissions Laws And Control In Circulation Fluidized Bed Boilers Burned Lignite

With the rapid development of industry, producing large amounts of greenhousegases, which make the problem of global warming become more and more seriously. Asa major greenhouse gas, N2O and its harm to the environment has drawn increasingattention.The concentration of NOx and SO2in the exhaust flue gas of CFB boiler is lowerthan the ordinary pulverized coal boiler, so this technology is developing very rapidly,but studies have shown that the concentration of N2O is higher than the ordinarypulverized coal boiler. The elevation of Yunnan is high, and there are many circulatingfluidized bed unit, and mostly fueled with lignite. Therefore, some studies about how toreduce the N2O emission concentration of the circulating fluidized bed boiler fired ligniteis taken.N2O generated in fuel combustion process from the fuel N. The whole combustionprocess was accompanied by the formation N2O and decomposition, and both wayscontained homogeneous and heterogeneous reactions, the extent of each kind of reactionis influenced by the environment.Based on the data got from tests about the concentration of pollutant emission undervariable conditions. This paper studies the relationship between the different amount oflimestone, bed temperature and oxygen content and N2O emission concentration changetrend. Experiment showed that, N2O emission concentration increased with limestoneinputs and the bed temperature decreased, increased with increasing bed pressure andoxygen content.Finally, considering the emission concentration of SO2, NO and N2O, and theparameters about the dust concentration, air flow and exhaust temperature, combinedwith the characteristics of lignite combustion, an operation control reference value aboutthe bed temperature, oxygen content and amount of limestone was given, in order toreduce pollutant emissions.