Air Preheater in a Steam Thermal Power Plant

What is Air Preheater in a Steam Thermal Power Plant?

There are two types of air preheaters used in steam generators of thermal power plants: one is a tubular preheater installed in the boiler flue, and the other is a regenerative air preheater. They can be arranged so that the gas flows horizontally or vertically across the rotating shaft.In steam thermal power plants, the air preheater (Air Preheater) is a key energy-saving device installed in the boiler’s tail flue. Its core function is to utilize the waste heat of the flue gas to preheat the combustion air entering the boiler, thereby improving the overall thermal efficiency of the boiler and reducing fuel consumption.

Functions of Air Preheater in a Steam Thermal Power Plant

• Recovering Waste Heat and Improving Thermal Efficiency:  The flue gas temperature at the boiler exhaust is still as high as 120–140℃. The air preheater transfers this waste heat to the cold air through heat exchange, significantly reducing the exhaust gas temperature. According to data, boiler efficiency can increase by approximately 1% for every 15–20℃ reduction in exhaust gas temperature.
• Improving Combustion Performance: The higher temperature of the preheated air makes fuel (especially coal) easier to ignite, burn more completely and stably, helping to improve combustion efficiency and reduce incomplete combustion losses.
• Reducing Fuel Consumption and Emissions: By improving thermal efficiency and combustion quality, the air preheater indirectly reduces coal consumption, thereby reducing emissions of pollutants such as carbon dioxide and nitrogen oxides.

What is the function of the air preheater in boiler ?
An air preheater is a crucial component in boiler systems, primarily responsible for enhancing the boiler’s efficiency. It achieves this by preheating the combustion air before it enters the boiler furnace, leading to several benefits:

Reduced fuel consumption: Preheating the combustion air significantly reduces the amount of fuel needed to reach the desired boiler temperature. This translates into lower fuel costs and a more environmentally friendly operation.
Improved combustion efficiency: By supplying preheated air, the combustion process becomes more efficient, leading to a more complete fuel burn. This results in higher heat release and better overall boiler performance.

Air Preheater in a Steam Thermal Power Plant:

Rotary air preheaters (regenerative type) are commonly used in thermal power plants due to their compact structure, light weight, and high heat transfer efficiency, making them particularly suitable for large-capacity units.

Air Preheater in a Steam Thermal Power Plant Working Principle (taking the rotary type as an example):

The air preheater contains a slowly rotating cylindrical rotor. The rotor is divided into multiple compartments, each containing heat storage plates (heat transfer elements).

Flue gas enters from the flue gas side, flows through the heat storage plates, heats them, and then exits after its temperature decreases.

As the rotor rotates, the heated heat storage plates rotate to the air side.

Cold air enters from the air side, absorbs heat from the heat storage plates, is preheated, and then enters the furnace for combustion.

After the heat storage plates cool down, they rotate back to the flue gas side, and the cycle repeats continuously, achieving continuous heat transfer.

This method belongs to regenerative heat exchange, in contrast to tubular (thermal conduction) air preheaters, which transfer heat indirectly through metal tube walls. They have a simple structure but are bulky and are rarely used in large power plants.

Why Datang Finned Tube and Heat Exchanger?

Datang has significant experiences and strong manufacturing process technologies. We adopted the most advanced manufacture equipments and testing instruments.
Certificates:ISO9001
Lead time: It depends on the scale of order. Generally, goods can be sent out within 60 days.
Service: Technical support can be provided at anytime.
Free maintenance:generally ,can be provided within warranty period if damage of the equipments is only caused naturally from human factors.
Packing: Generally, goods are packed according to per request.
Shipping: Datang locates in Cangzhou,Yanshan,China, it is very closed to Tianjin port.Also ,it has a strong ability of land transportation

RFQ

1.Request for Air Preheater in a Steam Thermal Power Plant             —— February 2, 2026

For CFB 1-2 Air Preheater Lower Tube Box
Tube OD: 40 mm
Tube Thickness: 2 mm
Length: 1832 mm
Material: Q355GNHA/ A572 Gr 50
QTY:1,217