介绍
空气预热器是提高锅炉热交换性能，降低热量损耗的一种预热设备。空气预热器的作用，是将锅炉尾部烟道中排出的烟气中携带的热量，通过散热片传导到进入锅炉前的空气中，将空气预热到一定的温度,从而提高锅炉系统热效率。
空气预热器多用于燃煤电站锅炉。可分为管箱式、回转式两种，其中回转式又分为风罩回转式和受热面回转式两种。电站锅炉较常采用受热面回转式预热器。在锅炉中的应用一般为两分仓、三分仓、四分仓式，其中四分仓较常用于循环流化床锅炉中。

工作原理
以回转式空气预热器为例说明空气预热器的原理，在工作时会缓慢的旋转，烟气会进入空预器的烟气侧后再被排出，而烟气中携带的热量会为空预器中的散热片所吸收，之后空预器缓慢旋转，散热片运动到空气侧，再将热量传递给进入锅炉前的空气。
空气预热器在锅炉中的应用多为三分仓式，附带有火警报警系统、间隙调整系统和变频控制系统。空气预热器的使用方便、操作简单、运行安全，并能提高锅炉系统的热交换性能，因此在烟气锅炉系统中有很普遍的使用。

Introduction

Air preheater is a kind of preheating equipment to improve the heat exchange performance of boiler and reduce heat loss. The function of air preheater is to transfer the heat from the flue gas discharged from the tail flue of the boiler to the air before entering the boiler through the radiator, and preheat the air to a certain temperature, so as to improve the thermal efficiency of the boiler system.

Air preheaters are mostly used in coal-fired utility boilers. It can be divided into tube box type and rotary type. The rotary type can be divided into wind hood rotary type and heating surface rotary type. The rotary preheater with heating surface is often used in power plant boilers. Generally, the application in boilers is two-compartment, three-compartment and four-compartment, among which the four-compartment is more commonly used in circulating fluidized bed boilers.

Working Principle

Taking rotary air preheater as an example, the principle of air preheater is explained. When working, the air preheater rotates slowly. The smoke will enter the smoke side of the air preheater and then be discharged. The heat carried in the flue gas will be absorbed by the radiator in the air preheater, then the air preheater rotates slowly, the radiator moves to the air side, and then transfers the heat to the air before entering the boiler.

The application of air preheater in boilers is mostly three-storey type with fire alarm system, clearance adjustment system and frequency conversion control system. Air preheater is widely used in flue gas boiler system because of its convenient use, simple operation and safe operation, and can improve the heat exchange performance of the boiler system.