Air heaters are used to heat air. Currently, they are mostly used in dust removal systems in thermal power plants. They can reduce the humidity in exhaust smoke and maintain the smoothness of air force in pipeline transportation. They are one of the indispensable supporting equipment for power plants.
Plate-type air heaters are mostly made of steel, with compact scaling. The main heat exchange equipment is made of 1.5-4mm thin steel plates. The steel plates are welded into rectangular boxes, and several boxes are assembled into a group. The entire air preheater consists of 2-4 boxes. The flue gas passes from top to bottom, passing through the outside of the box, while the air passes horizontally through the inside of the box, turning upward at the bottom, and interacting with the flue gas twice to transfer energy, so that the flue gas and air form a reverse flow, and obtain better heat transfer efficiency.
The air heater can heat the air to improve the thermal efficiency of fuel and boilers. The large amount of flue gas carried by the flue gas discharged from the flue at the tail of the boiler is transferred to the air through the equipment to preheat the air to a certain temperature. The main function of the air heater is to reduce the heat loss of the boiler, reduce the exhaust temperature, and recover the waste heat to improve the thermal efficiency of the boiler. When the combustion temperature in the boiler is stable, the loss of incomplete combustion can be reduced. Air heating uses the waste heat of flue gas to further reduce the exhaust loss.
The lower the ambient temperature in winter, the lower the working efficiency of the main unit in the air heater. When the ambient temperature in the air heater is lower than -2℃, the air heater is far different from the standard heating condition due to the ambient temperature. The air conditioning unit designed according to the standard working condition of the air heater can provide much less heat than the standard working condition in the air heater. The compressor in the air heater works at a high compression ratio, which will inevitably lead to a decrease in the volumetric efficiency and indicated efficiency of the compressor of the air heater.
We will use air heaters in many fields. We must correctly understand it and understand its role in order to use it better.