How To Clean Heat Exchanger Plates
Keeping the plate clean is one of the important conditions for maintaining a high heat transfer coefficient. Between the plates, the medium moves along a narrow, meandering flow path. Even if a less thick scale layer is produced, it will cause a change in the flow path, significantly affecting the movement of the fluid, increasing the pressure drop and reduce heat transfer coefficient.
In this method, a chemical solution is circulated through the heat exchanger to dissolve and discharge the dirt on the surface of the plates. This method does not need to disassemble the heat exchanger, which simplifies the cleaning process and reduces the labor level of cleaning. Since the plate corrugation can promote the turbulent flow of the cleaning liquid and facilitate the dissolution of fouling, the chemical cleaning method is an ideal method.
2.Mechanical (physical) cleaning
In this method, the plate is manually washed with a brush to achieve the purpose of removing dirt on the plate surface. Although this method is relatively straightforward, it is not easy to clean harder and thicker scale layers
3.comprehensive cleaning method
In the case where the dirt layer is relatively hard and thick, it is difficult to clean by using one of the above methods. The comprehensive method is to soften the scale layer first by chemical cleaning, and then remove the scale layer by mechanical (physical) cleaning method to keep the plate clean.
4.Precautions for cleaning
The solution should maintain a certain flow rate during chemical cleaning, generally 0.8-1.2 m/s. Its purpose is to increase the degree of solution turbulence.
Different chemical cleaning solutions should be used for different fouling. In addition to the frequently used diluted soda ash solution, 5% nitric acid solution can be used for the fouling. For the fouling generated in the soda ash production, 5% hydrochloric acid solution can be used. However, chemical lotions that corrode the plates should not be used.
Stainless steel plate are not allowed to be brushed with a carbon steel brush during mechanical (physical) cleaning to avoid accelerating plate corrosion . At the same time, the plate surface cannot be scratched or deformed.
The cleaned plate should be rinsed with water and dried, and the plate should be prevented from being deformed.