Internal cleaning method for air pre-heater

The invention discloses an air pre-heater interior cleaning method. Particles are gathered together, friction force is large, soot cannot be effectively removed through simple soot blowing, regular manual cleaning is still needed, and the labor intensity of manual cleaning is large. The method comprises the following steps that a first conveying pump conveys cleaning liquid in a cleaning liquid box into a rotor shell, and the cleaning liquid is used for soaking the inner wall of the rotor shell and an air pre-heater structure; then, an electric three-way valve is controlled to enable a first conveying pump to communicate with a spray head, cleaning liquid is sprayed into the rotor shell through the spray head, and dust and suspended solids adhering to the inner wall of the rotor shell and the surface of the air pre-heater structure are washed away; the cleaning liquid containing dust and suspended solids enters the filter box through the return pipe and then is subjected to triple filtration through the filte