A plate heat exchanger is a high-efficiency heat exchanger assembled from a series of metal sheets with a certain corrugated shape. Thin rectangular channels are formed between various plates to exchange heat through the plates. The reason and treatment method of internal leakage of plate heat exchanger?
(1) Causes of internal leakage in the heat exchanger
① Cracks or perforations due to plate corrosion due to improper plate selection. ② The operating conditions do not meet the design requirements. ③ The residual stress after cold stamping of the plate and the too small clamping size during assembly cause stress corrosion. ④ There is a slight leakage at the plate leakage groove, which causes the harmful substances (such as C1) in the medium to concentrate and corrode the plate. Example: A BR03 plate heat exchanger with a plate material of 254SMo in the sulfuric acid system of a certain aluminum industry limited company. After 5 months of operation, there was a corrosion and leakage of carbon steel pipe connection on the cooling water side. Through inspection, it was found that there was severe corrosion and cracking at the inlet of the plate acid solution and the diversion area. On-site analysis found that the process parameters such as operating temperature, flow rate and concentration of the system are beyond the design conditions, and the operating temperature is far beyond the applicable range of materials.
(2) Treatment method of heat exchanger internal leakage
① Replace the cracked or perforated plate, and use the light transmission method to find the plate crack on site. ②Adjust the operating parameters so that they meet the design conditions. ③ The clamping size should meet the requirements when repairing and assembling the heat exchanger. ④ Plate materials are reasonably matched.