SNCR Denitration Technology Transformation Of The Circulating Fluidized Bed Boiler In Baotou First Thermal Power Plant

Nitrogen oxides(NO_x)are the main emissions of coal-fired power plants.With the continuous development of economy,the demand for electricity is increasing,and the combustion of fossil fuels causes a great deal of pollution.In order to improve the quality of atmospheric environment,it is necessary to control the emission of NO_x.Therefore,it is of important engineering and practical significance to study the denitrification system in power plants.The average monthly discharge concentration of No.9 and 10 CFB boilers in Baotou first Thermal Power Plant is about 200~400mg/m~3,and the maximum NO_x period can reach 480mg/m~3.In order to meet the requirements of the new emission standard for air pollutants in thermal power plants(GB13223-2011),the NO_x emission concentration is not higher than the 100mg/m~3 limit requirement,the power plant adopts denitrification scheme to reduce NO_x emissions.Baotou first thermal power plant based on the actual operation,and combined with the current national emission standards for new power plant pollutants by denitrification technology programme,route verification and the investment cost is estimated for various power plants,finally decided to adopt the SNCR denitrification transformation scheme,and the use of urea as reducing agent.After modification,according to the inlet NO_x concentration 400mg/m~3,the outlet NO_x was controlled at 100mg/m~3,and the denitrification efficiency was 75%.Through the investment evaluation of the denitration project transformation,the project static investment is 14.25 million yuan,and the unit investment is about 57 yuan/kW.Among them,SNCR part investment is 9.85 million yuan,unit investment is 39.4 yuan/kW.When adopting SNCR technology,the annual operation cost is 8.48 million yuan,the unit NO_x emission reduction cost is 6.93 yuan/kg,and the unit generation increase cost is0.0062 yuan/kW.h.In accordance with the current denitration tariff subsidy standard(0.01 yuan/kW.h),after the denitration system put into operation,two units of annual denitrification tariff subsidies 13.75 million yuan.After the denitration project is completed,it has great environmental and social benefits to the location,and the total amount of NO_x discharged by two boilers in the year before using the denitrification unit reaches about 1840 tons.After the SNCR denitration plant is put into operation,the emission of two boilers is about 463 tons,and the total amount of NO_x can be reduced by about 1377 tons per year.The results showed that the denitration renovation and operation has great significance in NO_x emission reduction,and bring good environmental benefits for the local area.The construction of SNCR will help the localization of denitration equipment,and accumulate valuable experience for the design of SNCR denitrification,so as to provide reference for similar projects in the future.