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 tear at flue gas inlet.

Ancillary system

Rotary air preheater mainly includeds fire alarm(hot spot detection), clearance adjustment, frequency conversion control, lubricating oil system, rotor stop alarm system, soot blowing and cleaning system, etc..

The key problems affecting the performance of rotary air preheater are air leakage, corrosion and ash plugging. In the design of tubular air preheater, air flow rate and tube box size should be reasonably selected, or vibration isolation board should be installed along the direction of air flow to prevent cavity resonance.Vibration isolation board also have the function of eliminating noise. Air leakage of rotary air preheater is an important problem. Measures should be taken in desgin, manufacturing, installation and operation to keep reasonable sealing gap between dynamic and static components in thermal state.When burning high sulfur fuel, both tubular and rotary preheater are prone to corrosion and ash plugging.The preventive measures include:installing heater or hot air recirculation at the air inlet; using low oxygen combustion or mixing combustion additives to reduce the production of SO2 gas in flue gas; blowing ash regularly to keep the heating surface clean; using corrosion-resistant materials on the heating surface, etc.

Parameter

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.