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, recover waste heat and 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. According to relevant experience, when the air rises by 1.5℃ in the preheater, the exhaust temperature can be reduced by 1℃. After installing an air preheater in the boiler flue, if the air waste heat can be reduced to 150-160℃, the exhaust temperature can be reduced by 110-120℃, and the thermal efficiency of the boiler can be increased by 7%-7.5%. It can save 11%-12% of fuel.