Research On The SCR DeNOx Technology Applied In600ME Unit In Huaneng Shangan Power Plant

Environmental pollution caused by coal-fired power production is an important constraint against power industry development. NOX is one of the main pollutants produced from coal-fired power plants and its emission has been increasing as economy developing. With the publication of new standards for pollutants emission, NOX control after dust and SO2, will be the focus of environmental protection against pollutant emission from coal-fired power plants. To respond positively to the national and local government environmental policies and relieve environment pollution, De-NOX reconstruction was performed on the third phase project, 2 × 600 MW units in Shangan power plant.This paper described the state of De-NOX technologies for coal-fired power plant,and chose SCR technology as the main method for the De-NOX reconstruction project.The SCR reactors were arranged between the boiler economizer and air preheater, with high dust layout. Honeycomb catalyst was chosen to be built in SCR reactor, where the superficial velocity was 5.3m/s, and the flow with rate 6.9 m/s through the catalyst pores,to prevent catalyst attrition and plugging. The transformation process of the related equipments and its impact on boiler operation after the transformation were discussed.After De-NOX system went into operation, NOX concentration in flue gas after the system was 97.5mg / Nm3(6% O2), reduction of NOX was 13434.4t/a, and the decreased amount of pollution discharge fee for NOX emission was about 8.48 million Yuan(by 0.6/ equivalent basis). Experimental method was used to evaluate the De-NOx system performance, where operation parameters, inclusive of the De-NOX efficiency, NH3 slip rate, SO2/SO3 conversion rate, system pressure drop, the NH3/NOX molar ratio were tested, and its operating performance was analyzed. The showed that, except the amount of NH3 slip slightly exceeded, the other indexes could meet the performance requirements. Project investment estimation and economic evaluation showed that dynamic investment was 179.59 million Yuan, unit investment amount was 150 Yuan/kW,and the fluctuation of electrovalence during operating period because of denitration project was 10.02 Yuan / MWh.The above results showed that the De-NOX project construction and operation has good environmental and economic benefits for Shangan power plant and the local area.