Research on the effect of the flue gas recirculation on the combustion and operating economy of circulating fluidized bed boiler

Abstract To meet the requirements of the power grid’s deep peak shaving, a 300MW CFB boiler in a power plant transformed the flue gas recirculation. After the transformation, it is found that after putting into the flue gas recirculation, the main parameters of the boiler such as environmental protection emission value, the boiler operating bed temperature, and the inlet temperature of the separator had changed. To analyze the changes, this paper was carried out by related thermal state tests during the start-up or the normal operation of the boiler. The operating data of the boiler was collected before and after putting into the flue gas recirculation, and the influence of the gas recirculation on the main parameters and economic indicators of the boiler is quantitatively analyzed and discussed. The result shows that the technology of the flue gas recirculation can reduce the oxygen content in the dense phase area of the furnace and increases the reducing gas atmosphere to reduce the generation of NO X emission during the start-up or in the normal operation of the boiler. This provides a technical reference that optimizes the operation mode of the flue gas recirculation during the deep peak shaving in the CFB boiler.