Views:0 Author:Site Editor Publish Time: 2020-06-17 Origin:Site
Connection of chemical cleaning circuit
First close the inlet and outlet valves of the heat medium of the plate heat exchanger, and then close the inlet and outlet valves of the cold medium to drain the medium (usually water or steam). The inlet and outlet of the hot and cold medium are used as the cleaning liquid inlet, and the outlet and outlet of the hot and cold medium are used as the cleaning liquid outlet (if there is no outlet, you need to add and add a valve). The sequence of the medium outlet, as well as the cleaning pump, the cleaning tank, and the plastic pipe form a chemical cleaning cycle system.
Chemical cleaning process implementation
According to the chemical cleaning process, the concentration of the cleaning liquid in the cleaning tank should be detected every 1 h during the cycle to keep the concentration of the cleaning liquid constant. Keep it within the safe and effective range of 0 · 10 ~ 0 · 15mol / L, and add cleaning agent based on the measured data. Chemical cleaning without disassembling may take a long time, and can be combined with cyclic cleaning and osmotic cleaning. When the concentration of the cleaning agent does not change for 2 hours or the change is small, the cycle can be stopped.
After chemical cleaning, due to the small internal flow of the plate heat exchanger, there is always scale and slag (especially dirt) on the heat transfer sheet, so the cycle and scum need to be repeatedly washed away. Drain the waste liquid in the cleaning tank, fill it with fresh water, rinse it with a circulating pump, and drain the waste water. Repeat the flushing, and observe the water continuously until no more slag is discharged from the plate heat exchanger.
Neutralization is to neutralize the residual acid solution in the equipment after cleaning without corroding the equipment; passivation is to form an electronic conductor film on the metal surface that can inhibit the dissolution process of the metal. This film itself has a very slow dissolution rate in the medium. , So that it can keep the metal's anode dissolution rate at a small value. Since the chemical cleaning requires several sections of pipes connected to the plate heat exchanger, the heat transfer sheet is made of stainless steel and does not need to be neutralized and turbidized, but the pipes are made of steel. The scale and rust on the surface after cleaning are all cleaned. Remove and expose the nature of steel. It is in a very active and activated state and is susceptible to rust, so it needs to be neutralized and transparentized to prevent secondary rust.