Air Preheater

Core Functions：
Improving Boiler Efficiency: This is the primary purpose. By preheating the combustion air, the boiler requires less fuel to heat water into steam. Typically, boiler efficiency increases by about 1% for every 20°C increase in combustion air temperature.
Improving Combustion Conditions: Hot air promotes more complete and stable combustion (especially for pulverized coal in power plant boilers), reducing the formation of unburned carbon particles and carbon monoxide.
Drying and Preheating Fuel: In coal-fired boilers, hot air is typically used to transport pulverized coal to the burner and dry the coal before combustion, which is crucial for efficient combustion.
Mitigating Low-Temperature Corrosion: By increasing the temperature of metal components at the boiler tail end (such as economizers), it helps prevent dew point corrosion caused by the condensation of sulfuric acid vapors from the flue gas on the walls.
Main Types of Air Preheaters:
1. Tubular Air Preheater: A simple static heat exchanger.
Working Principle: Flue gas flows through the tube, while combustion air flows laterally across the tube. The metal tube wall acts as a heat transfer surface, transferring heat from the flue gas to the air.
2. Rotary Air Preheater: A dynamic, continuously rotating heat exchanger.
Working Principle: The core component is a rotor filled with heat storage elements (corrugated metal plates), slowly rotated by a motor.
Flue Gas Side: Part of the rotor passes through the flue gas passage, where the heat storage elements absorb heat from the flue gas.
Air Side: The other part of the rotor passes through the air passage, where the high-temperature heat storage elements release the stored heat to the cool air.
Through the continuous rotation of the rotor, a cyclical heat absorption and release process is completed.

Application Scenarios: 
Power Industry: Especially for large coal-fired power plant boilers, it is a key piece of equipment for improving efficiency and reducing coal consumption.
Metallurgical industry: Used in blast furnaces, heating furnaces, annealing furnaces, etc., to recover waste heat from high-temperature flue gas, saving fuel and increasing furnace temperature.
Chemical and oil refining industries: Used in various process heating furnaces and boilers to improve the thermal efficiency of the entire production unit.
Building materials industry: Such as cement kilns, glass melting furnaces, etc., utilizing waste heat for combustion, it is an important piece of equipment for achieving energy conservation and emission reduction.