Hofmann (Beijing) Engineering Technology Co.,Ltd
Add:6F, East International Building, No.2 DongZhiMen Outside Street, DongCheng District, Beijing
As a compact and efficient heat exchange equipment, plate heat exchangers have been developed for nearly 100 years and have been widely used in some sectors (such as food, pharmaceutical, chlor-alkali, etc.), but due to their temperature resistance and pressure resistance. The lack of capacity such as corrosion resistance limits the scope of application. In the evaporation section of the ion-exchange membrane workshop of a factory in our company, two BR0.2-type plate heat exchangers are used to cool the lye in parallel. The hot fluid inlet medium of the heat exchanger is an alkali solution (containing a small amount of salt) with a temperature above 85 °C. The outlet temperature is approximately 50 °C. The plate heat exchanger is made of 304 stainless steel plate, which suppresses the adult shape 0.6m m corrugated plate, and is composed of a labyrinth-shaped fluid passage with a reversed left and right herringbone groove. After two years of use, the plate heat exchanger leaked, and the plate heat exchanger was prevented from leaking after one month. The following is a brief analysis of the reasons for the failure of the plate heat exchanger.
The detachable plate heat exchanger leaks when used, and the failure of the gasket material is also an important factor in addition to the corrosion of the plate. There are mainly the following ways: 1 When the rubber gasket material is in contact with the fluid, when a fluid component penetrates into the rubber, sometimes the soluble matter can be extracted, resulting in swelling of the rubber gasket; 2 the presence of halogen and ozone The effect is to soften the gasket or cause stress corrosion cracking. 3 Under certain conditions, especially at high temperatures, the elastomer will decompose and release chemicals that will corrode the sheet material itself, such as FPM rubber, which will release oxygen. After disassembling the plate heat exchanger, it was found that the cold fluid end surface of the plate was bright, a small amount of black scale was locally, the number of corrosion pits was small and did not penetrate, and there was black deposit in the corrosion pit, so it can be inferred as a gasket. Piece of corrosion exists.