Cleaning method of plate heat exchanger
1. Pickling: Use pickling liquid and impurities such as scale to react, which is convenient for the subsequent process.
2. Alkaline washing: The application of alkaline washing to remove organic compounds and oil stains and to soften the dirt makes it easier to remove. The time is between 10-24 hours and the temperature is usually 85 degrees Celsius. At the same time, local impurities are taken away from the surface.
3. Neutralization and passivation; passivation agent is used to form a passivation film on the surface of the metal.
4. For rinsing, the rinsing liquid is combined with the iron ions remaining in the system to reduce the content of [Fe2+/Fe3+], in order to prepare for passivation, so as to prevent the equipment metal from returning rust.
5. Water rinse after alkaline washing: to remove residual alkaline cleaning solution and generate soluble substances.
6. Water rinse after pickling: To remove the residual acid and the falling solid particles, at the same time remove the secondary rust that appears during the water rinse.
7. Water flushing and system pressure test: Water flushing and pressure test are used to remove ash, silt, metal oxides and loose dirt in the system, and the flow rate is less than 0.3 meters.