Scale cleaning of heat exchanger:

　　1. Water washing: after alkali washing, wash the heat exchanger repeatedly with clean softened water to completely clean the residues in the heat exchanger.

　　2. Acid pickling: soak the heat exchanger filled with acid solution for 2 h in static state, then conduct dynamic circulation for 3-4 h. during this period, clean the heat exchanger with positive negative replacement every other time. After pickling, if the pH value of the acid is greater than 2, the acid can be reused.

　　3. Flushing: prior to acid cleaning, the heat exchanger shall be flushed in an open way so that there is no mud, scale other impurities inside the heat exchanger, which can only improve the effect of acid cleaning, but also reduce the acid consumption of acid cleaning. Pour the cleaning liquid into the cleaning equipment, then write it into the heat exchanger.

　　4. Alkali washing: after acid washing, NaOH, Na2CO3, Na3PO4 softened water shall be used to manufacture the heat exchanger in a certain proportion, the dynamic circulation method shall be used to alkali wash the heat exchanger to neutralize the acid alkali, so that the plate of the heat exchanger will be corroded.

　　The main reason for the formation of scale is that the water contains calcium magnesium salts with low solubility, which have common characteristics. Their solubility decreases with the rise of water temperature, they become difficult to contain salts. If the heat exchanger wants to maintain stable operation, it is necessary to do a good job of cleaning in time to prevent the occurrence of blockage.