Performance Analysis of a New Type Economizer System for Active Control of Exhaust Flue Gas Temperature in a 600 MW Power Plant

A new type of bypass staged economizer system is presented in this paper. The calculation model of the bypass staged economizer and ordinary LPE were established based on a 600 MW unit. The performance analysis for important operating parameters of the presented economizer system such as exhaust gas temperature and bypass flue gas ratio are carried out. Simulation results showed that, when the scheme of the bypass staged economizer was adopted, the temperature of the flue gas entering the electrostatic precipitator (ESP) can be reduced to 95°C, which can greatly improve unit efficiency, reduce standard coal equivalent (SCE) consumption by 2.8g/kWh. Compared with the traditional LPE, it can reduce SCE consumption by 1.59g/kWh. In addition, the technology can also achieve the active control of the exhaust flue gas temperature by changing the bypass flue gas ratio. The different flue gas temperatures correspond to different bypass flue gas ratios. And the optimum bypass flue gas ratio was calculated in different exhaust gas temperature conditions.