Three measures for plate corrosion prevention of stainless steel plate heat exchanger

The utility model is composed of a plurality of plates which are alternately arranged and clamped together. There is a gap in the cross contact gap within the medium will flow, the concentration gap exists inside and outside oxygen poor, resulting in crevice corrosion, resulting in crevice corrosion will happen in certain regions of priority, which is the main reason of corrosion pits occurred in the contacts of the.

Plate heat exchanger is by stamping molding, in general, cold processing has little influence on the pitting potential, but the cold processing usually makes pitting density increases, this is because the cold processing increases the dislocation density and dislocation in the surface outcrop to form pits. When the plate is assembled, the contact point of the herringbone convex surface is easy to be extruded and the surface oxide film is damaged. The convex surface of the herringbone is the largest part of the cold deformation, and there is crevice corrosion in this part, so the pitting pit mainly occurs in the convex part of the cold working deformation. Therefore, the corrosion failure of the plate heat exchanger is caused by the crevice corrosion of the plate contact at Cl-.

The corrosion failure of stainless steel plate in plate heat exchanger is caused by the crevice corrosion at the contact point of the plate, which is caused by Cl- in the medium:

1, reduce the content of Cl- ions in the medium. Cl- in acrylic fiber production comes from two aspects: first, raw materials into; the two is the introduction of desalted water. In order to reduce or avoid the corrosion of 316 stainless steel source, should be good raw materials, strictly control the content of sodium allyl sulfonate NaCl, and strictly out of water Cl- index.

2, to ensure that the equipment passivation film intact. The defect of passivation film is the internal cause of corrosion, the defects of local residual from stainless steel plate in the cold stamping process may cause stress, damage and adhesion of the passivation film, processing and installation in the process of construction of dirt and welding slag, bump damage signs harm, so be sure to ensure correct installation of sheet passivation good film.

3, the plate assembly after the formation of a multi slot structure, such as contacts, plate sealing between the bottom and other parts, and easy to cause the gap enrichment of C1-, when the dirt sheet surface is serious, the corrosive elements in the medium (Cl, S) a large number of attached dirt and dirt in the gap at the bottom enrichment, easy to cause the crevice corrosion of contact point. To this end, the correct selection of materials, the correct assembly, regular scaling to destroy the formation of corrosion conditions and incubation period, reduce the content of harmful ions such as chloride ions in the media, can effectively prevent the crevice corrosion at the plate contact. Titanium is the best structural material for pitting corrosion and crevice corrosion. Each plate of AI Reed has at least two plates, and the heat transfer and pressure drop of the heat exchanger can be integrated by using the technology of thermal mixing. The inner bypass, the double channel technology and the unequal flow cross section assembly provide the perfect solution for the two sides of the medium flow rate difference.