Flue Gas Whitening in Coal-Fired Power Plants

Overview of Flue Gas Whitening Project in Coal-fired Power Plants:
Coal-fired power plants commonly use wet flue gas desulfurization processes. After wet desulfurization, the flue gas temperature is around 55°C. At this temperature, the saturated wet flue gas, when directly discharged into the atmosphere, condenses into water droplets upon cooling, forming "white plumes" under sunlight refraction, causing certain visual pollution to surrounding residents.

Working Principle of Flue Gas Whitening in Coal-fired Boilers:
Coal-fired power plants generally adopt the MGGH whitening process route, which involves condensation and reheating for flue gas whitening. The MGGH system uses water as a medium, absorbing heat from high-temperature flue gas before desulfurization through water circulation to heat the purified flue gas after desulfurization. This raises the flue gas temperature, increases the elevation of flue gas emissions, and reduces the ground-level concentration of pollutants. The MGGH system consists of a flue gas cooler and a flue gas reheater, equipped with circulating water pumps and corresponding water pipelines. The system also includes pressure stabilization, chemical dosing, and water replenishment devices to ensure safe and stable operation.

Advantages of the MGGH System:
1. It is an upgraded alternative to traditional GGH, overcoming issues such as easy clogging, wear, and difficulty in cleaning associated with rotary GGH.
2. It utilizes waste heat to heat the end flue gas for whitening, requiring no additional energy consumption.
3. It reduces low-temperature corrosion of flue ducts and chimneys by flue gas.
4. It removes some pollutants from the flue gas, lowering the emission indicators of flue gas pollutants.