How to reduce pressure drop in plate heat exchanger
1.Remove dirt or plate fouling in the heat exchanger flow path. For newly operated systems, clean once a week according to actual conditions. When cleaning the surface scale of the plate (mainly CaCO.), use a 0.3 sulfamic acid solution or a 0.8 nitric acid solution containing 0.3 urotropin, 0.2 aniline, 0.1 potassium thiocyanate as the cleaning solution, and the cleaning temperature is 40-60 ° C. . When disassembling equipment for chemical immersion cleaning, open the heat exchanger inlet and outlet or install the DN25 cleaning port on the medium inlet and outlet nozzles when installing the equipment, and inject the prepared cleaning liquid into the equipment, soak it and rinse it with water. Clean the residual acid to make the pH ≥ 7. When disassembling the cleaning, soak the plate in the cleaning solution for 30 min, then use a soft brush to rub the scale and clean it with water finally . Avoid to damage the plates and rubber gasket during the cleaning process. If the mechanical backwashing method is not disassembled, a nozzle should be connected to the medium inlet and outlet pipes in advance, the equipment should be connected to the mechanical cleaning vehicle, and the cleaning liquid should be injected into the equipment in the opposite direction of the medium flow. The cycle cleaning time is 10-15 min. The medium flow rate is controlled at 0.05 to 0.15 m/s. Finally, recycle with water several times to control the mass concentration of Cl in the water below 25 mg/I.
2.It is better to use soft water after softening treatment for the secondary circulating water. Generally, the mass concentration of suspended solids in water is not more than 5 mg/L, the impurity diameter is not more than 3 mm, and pH is ≥ 7. When the water temperature is not more than 95 °C, the concentration of Ca and Mg should be no more than 2 mmol/L; when the water temperature is greater than 95|C, the concentration of Ca and Mg should be no more than 0.3 mmol/L, and the concentration of dissolved oxygen should be no more than 0.1 mg/L.
3.For the central heating system, a method of primary water to the secondary water supply can be used.