Abstract:With more attention paid to environmental protection，the environmental protection supervision of key pollutant discharge enterprises has been strengthened，constraints on emission limits of air pollutants from thermal power plant become increasingly strict. To assure the up-to-standard release, technological transformations have been made to lower the emission of SO2 and NOx. In this article, To meet the national pollutant discharge requirements.In this article, two circulating fluidized bed boilers in ** Power Plant, Without the construction of an off-furnace desulfurization device, the analysis of the combustion of the boiler will start from two aspects: how to reduce the operating temperature of the boiler and improve the use efficiency of the desulfurizer，Proposed the idea of solving the problem.Through the reformation of the boiler limestone system and the electrostatic dust removal fly ash conveying system, the reuse technology was used to increase the utilization of the desulfurizer in the furnace. At the same time, the combustion conditions of the boiler are improved to inhibit the generation of pollutants such as SO2 and NOx.This article compares and analyzes the situation before and after the boiler transformation，Through the test data from the boiler operation safety, economical, calcium-sulfur ratio, thermal efficiency, pollutant emissions and other indicators in detail.