Ultra-low emission transformation of 600 MW supercritical circulating fluidized bed boilers unit

Abstract With the introduction of ultra-low emission environmental protection policies in national and local coal-fired power plants, ultra-low emission transformation of coal-fired power plants is required to be carried out in an all-round way. Under this background, the first 600 MW supercritical circulating fluidized bed (SCCFB) boiler unit in the world have carried out the demonstration of the technical route of ultra-low emission transformation and the research of key technologies. By adopting limestone desulphurization and low nitrogen combustion in furnace, selective non-catalytic reduction (SNCR) technology outside furnace and the integrated desulfurization and dust removal process of flue gas circulating fluidized bed (CFB-FGD), the unit realizes the technical route of ultra-low emission, and has good investment and operation economy, which can adapt to the development trend of environmental protection in the future. The CFB-FGD and dust removal system can further improve the operation economy of the boiler by setting pre-electrostatic precipitator (pre-ESP), designing double-tower and optimizing the single-tower switching mode, optimizing the pressure margin of the induced draft fan, and adopting the coordinated desulphurization operation mode inside and outside the furnace. The research results can provide a reference for the selection of ultra-low emission transformation for 660MW ultra-supercritical CFB boiler unit.