Mandu Engineering introduces the steps for cleaning scale from plate heat exchangers

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Specific steps for cleaning scale: 1) Flushing: Before acid cleaning, the heat exchanger should be flushed openly to remove any impurities such as mud and scale from its interior. This not only improves the effectiveness of the acid cleaning process but also reduces the amount of acid required. 2) Pour the cleaning solution into the cleaning equipment, and then inject it into the heat exchanger. 3) Acid cleaning: Immerse the heat exchanger filled with acid solution statically for 2 hours, then subject it to continuous dynamic circulation for 3–4 hours, during which cleaning is carried out alternately in forward and reverse directions every 0.5 hours. After the pickling process is complete, if the pH value of the acid solution is greater than 2, it can be reused; otherwise, it should be diluted and neutralized before being discarded. 4) Alkali cleaning: After acid cleaning, a solution prepared from NaOH, Na3PO4, and softened water in specific proportions is used to carry out alkali cleaning of the heat exchanger through dynamic circulation, thereby achieving acid-base neutralization and preventing further corrosion of the heat exchanger plates. 5) Water washing: After the alkaline cleaning is complete, the heat exchanger is rinsed repeatedly with clean softened water for 0.5 hours to thoroughly remove any residues remaining inside it. 6) Recording: During the cleaning process, the time taken for each step should be carefully recorded in order to assess the effectiveness of the cleaning. In industrial systems such as power plants and large-scale wastewater treatment facilities, due to the large size of the heat exchangers and the dirty water quality, these exchangers often become clogged and scaled. In such cases, it becomes very difficult to disassemble them for cleaning. The main solutions are reverse flushing of the system and built-in filters.