Flue Gas Circulating Modeling of Oxy-fuel Combustion Boiler and the Volume Change Characteristics of the Flue Gas Components

Based on the pulverized coal boiler of the 300 MW unit,the volume changing trends of the flue gas components with different flue gas recirculation types and the boiler are leakage coefficients were calculated and analyzed.According to the flue gas recirculation type of the oxy-fuel combustion,the volume calculating model of the flue gas components were established,and the detailed volume calculation for each component of the flue gas was carried out with the iteration method.The results show that the volume ratios of oxygen and nitrogen of the flue gas in the furnace exit were mainly affected by the air leakage coefficient,but the volume ratios of water vapor and carbon dioxide of the flue gas were mainly affected by the flue gas recirculation type.These results are great significance for the design and arrangement of the heat exchangers of the oxy-fuel combustion boilers.