According to the pressure, medium, safety level and operation mode, the cleaning system can be divided into high pressure, medium and low pressure, explosion-proof and non explosion-proof, original liquid cleaning or imported cleaning medium and other different types of combinations. The overall optimization of the cleaning system, the selection of the cleaning pump and the setting of the cleaning head all need professional knowledge. The evaporative crystallization system needs to protect and clean the whole system during intermittent operation and shutdown or maintenance. Due to the different media, some media are toxic, some are flammable and explosive, some crystallize and become viscous when the temperature drops. The system needs to design the corresponding inert gas protection or cleaning device before the shutdown. Where it is impossible to reach manually, it needs to design an automatic online cleaning system to clean the main device and auxiliary device, so as to ensure the safety of each section Good operation.