Application Of Low Temperature Economizer In 600MW Thermal Power Unit

The coal consumption of thermal power plants in China is as high as 50% of the total coal production in the country.In the process of coal-fired power generation,the heat loss of boilers is the largest among the heat losses of the whole plant,and it is also the biggest factor affecting the efficiency of the unit,affecting the heat of exhaustion.The main factor of the loss is the boiler exhaust temperature.The waste heat resource of the boiler is caused by the excessively high exhaust gas temperature,which is a common phenomenon in China’s power plants.According to the statistics of a 600 MW unit power plant in China,the average annual exhaust gas temperature of the boiler is close to 130.0 °C,and the full-load exhaust gas temperature even reaches 150.0 °C.Excessive exhaust gas temperature has a great impact on boiler efficiency and greatly increases the energy consumption of desulfurization system,so that waste heat and heat resources are all wasted in the desulfurization system.According to the process flow and structural characteristics of thermal power plant,this paper analyzes the problem that the high exhaust gas temperature of boilers in thermal power plants affects the economics of boilers,and proposes to add lowtemperature economizers to introduce high-temperature flue gas from the original boiler to the desulfurization system.The increased low temperature economizer is used to heat the condensate before entering the boiler,and the detailed analysis of the inlet water temperature selection and the heating surface arrangement in the scheme is carried out,and the low temperature corrosion and heat transfer tubes such as the heated surface must be solved in the actual project.In addition,the project must be solved in practice,such as heat surface low temperature corrosion,heat transfer tube wall temperature calculation,H-type fin tube detailed design parameters,heating surface antiaccumulation ash,wear,leakage prevention and control measures,heat exchanger arrangement type is discussed.Finally,the low-temperature economizer was put into operation,and the lowtemperature economizer flue gas flow after the reformation,the low-temperature economizer inlet and outlet temperature,the low-temperature economizer flue gas side pressure drop,the low-temperature economizer air leakage rate,and the low temperature were recorded in detail.Performance parameters such as water side resistance of economizer,and analysis of test data and test results.The test results show that the addition of low temperature economizer can significantly improve boiler efficiency and reduce coal consumption,thereby effectively increasing power generation revenue and reducing greenhouse gas emissions.