Reconstruction And Operation Optimization Of Flue Gas Waste Heat System Of 1000 MW Power Plant Boiler

The exhaust gas temperature of boilers in active thermal power units in China is generally maintained at about 125 ～ 150 °C,which is pretty high.The heat loss caused by exhaust gas can reach 3 % ～ 8 % of the total input fuel heat.Therefore waste heat recovery and utilization of boiler exhaust gas can significantly improve the unit efficiency,reduce the power supply coal consumption,improve the safety and reliability,and have significant economic benefits.In this paper,aiming at the prominent problems of high exhaust temperature and blockage of heat storage element of flue gas waste heat recovery equipment(air preheater)of 1000 MW power plant boiler,based on thermodynamic calculation and evaluation of technical feasibility and economic benefit,the flue gas waste heat recovery scheme of combined open independent circulation system of air heater and low temperature economizer is finally determined,which is through optimization and comparison and combined with production practice.After engineering design and actual transformation,the test results showed that the power supply coal consumption was saved by 2.15 g / k W·h,2.28 g / k W·h and 3.23 g / k W·h under 100 %,75 % and50 % THA conditions.On this basis,the operation control parameters,the condensation water flow of the air heater and the operation mode of the booster pump are optimized.As a result,the heat consumption of the turbine is further reduced by more than 70 k J / k W·h,which improves the annual operation economy of the unit.Through the transformation and operation optimization of the flue gas waste heat utilization system of the ultra-supercritical boiler of 1000 MW units,this paper summarizes the establishment of a collaborative optimization operation mode of low-temperature economizer and air heater,which not only solves the problem of air preheater blockage,but also realizes the deep utilization of flue gas waste heat and improves the efficiency of the unit.This paper provides practical reference for the transformation of similar units and the selection and operation adjustment of new units.There are 31 figures,27 tables and 56 references in this paper.