Research On The Retrofit Of Low Temperature Economizer For #5 Unit In Dalate Power Plant

North United Power Co.Ltd.Dalate three power plant unit 5 boiler with SG-1018/18.55-M864,produced by Shanghai Boiler Works Ltd,a subcritical reheat,natural circulation,single chamber,four corner tangential combustion,PI type arrangement,solidslag pulverized coal furnace.The coal pulverizing system adopts medium speed coal mill positive pressure direct blowing pulverizing system,and the burner is arranged in four corners.Equipped with rotary air preheater and electric dust collector.Under rated operating conditions,the exhaust gas temperature is 122℃,and the average annual exhaust gas temperature in 2015 is close to the temperature of 130℃,and the full load exhaust gas temperature reaches to 145℃.On the one hand,the high exhaust temperature on the one hand makes the boiler flue gas heat loss increases,the dust removal efficiency is reduced;on the other hand,the amount of water in the wet desulfurization device is greatly increased,resulting in the waste of water resources.In order to promote energy saving and emission reduction,to improve the efficiency of the unit,to improve the efficiency of the unit,and to solve the problem of high exhaust temperature of the unit,the three unit of Dalate power plant was set up with a low temperature economizer system.This paper analyses the system analysis,including: the existing units existing problems and reformation scheme analysis,key technology research,analysis,technical and economic transformation of the experimental data,the study provide a reference for the improvement of the same type of other units in Dalate power plant.Low temperature economizer system province precipitator flue gas entrance temperature from 145 ℃ to 95 ℃,the condensed water temperature from 70 ℃ to110 ℃,No.5 boiler economizer was put into operation,the load in different operating conditions,unit heat consumption and power consumption are decreased in different degree.And good safety,moderate investment,the normal operation of the boiler does not have any negative impact.