Corrosion resistance of plate heat exchanger

Because the internal components of the plate heat exchanger are usually made of stainless steel, the corrosion resistance of stainless steel is particularly important. For the corrosion resistance standard of stainless steel material, the corrosion resistance of stainless steel can be analyzed by referring to the book "Circulating Water Treatment in Thermal Power Plants". According to different chloride ion content and different temperature corrosion limits of different materials, the influence of chloride ion content of cooling water on material selection was analyzed for plate heat exchangers with circulating water as cooling medium.

(1), T304 stainless steel chloride ion content is 0-200mg / L

(2), T316 stainless steel chloride ion content is <1000mg / L

(3), T317 stainless steel chloride ion content is <5000mg / L

In the process of petrochemical plants, pharmaceutical production equipment, food production system design, etc., the selection of equipment materials often takes into account various factors, among which corrosion is one of the important factors to consider, especially considering the long-term continuous operation of system equipment. To ensure that the equipment is not leaking or liquid, it is more important to choose the appropriate anti-corrosion equipment. Here, the possible corrosion of the plate heat exchanger is analyzed and the influence of the chloride ion content of the circulating medium on the material selection is discussed for the plate heat exchanger with circulating water or other medium as the cooling source.

We know that Brazed Plate Heat Exchanger is widely used due to their high heat transfer efficiency, compact structure, convenient disassembly, small footprint and wide application range. The plate heat exchanger consists of two side pressure plates, a plurality of inner plates, and a sealing rubber pad. The hot and cold medium enters and exits the nozzle and tightens the lead screw. Guide rod and other components. In general, 304 can withstand chloride ion concentration of about 200mg / L, 316L can withstand 800mg / L or so. If the system pressure is high (5~6Bar), the chloride ion concentration is higher than 10000mg/L, 316L will be perforated for two years, for the plate heat exchanger used for non-corrosion by the cold medium, the lateral pressure plate at both ends The material of the inlet and outlet is carbon steel, and the inner plate is usually pressed with stainless steel or alloy plate of 0.5~0.8mm thickness. Since the chloride ion in the water will cause different degrees of corrosion to stainless steel and alloy steel, the choice of the material of the inner plate for the plate heat exchanger which is not corroded by the cold medium depends on the content of chloride ion in the circulating cooling water. Of course, the temperature is also the main factor determining the degree of corrosion of chloride ions on the inner sheet. Therefore, it is necessary to select the appropriate stainless steel raw materials according to different industrial mines to ensure the normal operation of the system.
Key words: corrosion; circulating cooling water; chloride ion; plate heat exchanger; temperature l cooler; heat exchanger; Condenser; Welded Plate Heat Exchanger; brazed plate heat exchanger; gasket plate heat exchanger.