During long-term operation of plate heat exchangers, aging of gaskets, plate fouling, and medium corrosion are common issues that procurement personnel need to pay attention to. Taking the BR-70 plate heat exchanger as an example, its herringbone corrugated plates enhance the heat transfer coefficient by increasing fluid turbulence, but the pressure drop is relatively high; horizontal straight corrugations are suitable for high-viscosity media or working conditions where a smaller pressure drop is allowed. Before procurement, the complete composition, concentration, operating temperature, and whether the medium contains particulate matter should be verified, and based on this, the plate material (such as 304, 316L, titanium) and gasket material (such as nitrile, EPDM, fluororubber) should be selected.
During the selection stage, technical engineers often encounter situations where only the hot-side inlet temperature and flow rate are provided on site, while the cold-side outlet temperature is undetermined. In this case, the cold-side flow rate can be estimated according to the heat balance equation, or the required heat exchange area can be preliminarily calculated based on empirical heat transfer coefficient ranges, but a margin of 10% to 20% should be reserved. During maintenance, if the actual heat exchange capacity is found to be insufficient, the degree of plate fouling and whether the gaskets have internal leakage should be checked.
Regularly check the inlet and outlet pressure difference. An increase in pressure difference usually indicates blockage or fouling of the channels between plates. Avoid using wire brushes during cleaning to prevent scratching the passivation film on the plate surface. When disassembling and assembling the plate pack, the clamping bolts should be tightened evenly in a diagonal sequence to prevent gasket misalignment. For long-term shutdown, the medium should be drained to avoid chloride ion corrosion.
Procurement personnel should require suppliers to provide plate material certificates and temperature and pressure resistance parameters for gaskets. For media containing particulate matter, it is recommended to install a filter at the front end. When replacing gaskets, it is necessary to confirm that they match the original plate grooves.
