Keeping the plate frame heat exchangers plates clean is one of the important conditions for maintaining high heat transfer coefficients of plate heat exchangers. The medium between the plates moves along the narrow and zigzag flow path. Even if the scale layer is not too thick, it will cause the change of the flow path, which will significantly affect the fluid movement, increase the pressure drop and reduce the heat transfer coefficient .A sugar factory uses a plate heat exchanger for heating. Because the secondary water is not treated well, the flow channel is blocked in only two months during use and cannot continue to operate.
1. Chemical cleaning method. This method circulates a chemical solution through a heat exchanger to dissolve and discharge dirt on the surface of the plate. This method does not require disassembling the heat exchanger, which simplifies the cleaning process and reduces the labor of cleaning. Since the plate ripple can promote the turbulent turbulence of the cleaning liquid, it is beneficial to the dissolution of the scale layer. Therefore, chemical cleaning is an ideal method.
2. The mechanical (physical) cleaning method is to manually wash the plate with a brush to achieve the purpose of removing dirt on the surface of the plate. Although this method is relatively straightforward, it is difficult to clean the hard and thick scale layer.
3. The comprehensive method is to soften the scale layer by chemical cleaning method, and then remove the scale layer by mechanical (physical) cleaning method to keep the plate clean.
4. Precautions for plate heat exchanger plate cleaning
(1) The solution should maintain a certain flow rate during chemical cleaning (generally 0.8 to 1.2 m / s). The aim is to increase the degree of turbulence of the solution.
(2) Carbon steel brushes are not allowed to scrub stainless steel sheets during mechanical (physical) cleaning, so as not to accelerate the corrosion of the sheet. At the same time, the surface of the plate must not be scratched or deformed.
(3) After cleaning, the boards shall be rinsed with water and wiped dry. The boards shall be prevented from deforming when placed.