Zhangjiagang HuaDong Boiler Co., Ltd.
Zhangjiagang HuaDong Boiler Co., Ltd.
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General Introduction
Air preheater is a kind of equipment which can improve the heat exchange performance of the boiler and reduce the energy consumption. The function of the air preheater is to heat the flue gas discharged from the tail flue of the boiler and transmit it to the air before entering the boiler through the radiator, so as to preheat the air to a certain temperature.
The air preheater is generally used for coal-fired boilers in power station.It can be divided into tubular type and rotary type. The rotary type can be further divided into wind hood rotary type and heating surface rotary type.Power stations usually use the heating surface rotary air preheater. Generally, the application in boilers is two-compartment, three-compartment and four-compartment, among which the four-compartment is more commonly used in CFB boilers.
Working principles
Take the rotary type as a example to illustrate the working principles of air preheaters, when under operation, it would be slowly rotating, and exhaust gas will enter the gas flue side of air preheater, and then be dicharged. The heat carried by the gas flue will be absorbed by the cooling ribs of the air preheater, then the air preheater will be rotating slowly, the cooling ribs work to the side of the air, delivering the heat to the air before the air enters the boiler.
Classification
According to the way of heat transfer, the air preheater can be divided into two types:heat conduction type and regeneration type.Among the heat conduction type, tubular air preheater is most commonly used.With the increase of boiler parameters and capacity, the heating surface of tubular air preheater increases, which brings difficulties to the arrangement of the tail heating surface. Therefore, most of the large capacity units adopt a compact, light weight rotary air preheater. Air preheater is generally divided into three types: plate type, rotary type and tubular type.
The main heat transfer component of tubular air preheater is thin-walled steel tube. The tubular air preheaters are mostly cubic. The steel tubes are arranged vertically and staggered with each other. Both ends are welded on the upper and lower tube sheets.The tubular air preheater is equipped with an intermediate tube sheet in the tube box. The flue gas passes through the preheater up and down the pipe, while the air passes through the preheater horizontally to complete heat transfer.
Tubular air preheater is widely used in power station boilers and industrial boilers because of its advantages of good sealing, high heat transfer efficiency, easy manufacturing and processing. The shortcomings of tubular air preheater are large volume, easy ash plugging of steel tube content, difficult cleaning and easy wear and
Parameter
Layout item | Horizontal layout | Vertical layout |
| Tube arrangement | staggered arrangement / | staggered arrangement / |
| Sealing of pipe and plate | Packing heat- resistant material/ | welding |
| Anti-wearing | a,when gas scours external tube, welcoming smoke tubes have protective tile | |
Enamel air preheater products are classified as following by application
1.Enamel heat exchanger designed for denitration renovation projects
2.Enamel heat exchanger for circulating fluidized bed boiler and pulverized coal boilers Heat
exchanger parts for garbage incinerators and biomass boilers
3.Heat exchanger parts for grate furnaces, like chain grate furnaces4.Heat exchanger parts for gas-fueled boilers, such as kerosene boilers, coke ovens, etc.