The plate heat exchanger is composed of a set of corrugated stainless steel metal plates with holes in the corners of the heat transfer plate for the passage of two heat transfer fluids. Plate heat exchanger plates are the most important heat transfer link in the plate exchange system, and their quality directly affects the service life of the equipment. During parameter selection and design, the manufacturer will repeat the design strictly in accordance with the parameters provided by the customer, and the physical properties of the flowing medium will be confirmed to ensure that the corresponding material is selected to avoid leakage. So what kind of heat exchanger plate should be selected for different media?
(1) Water. We generally choose stainless steel 304 for common tap water and purified water. If it is well water, river water, closed circulating water and other media, we have to consider using 316L because these media components are more complicated. The corrosion resistance of 304 is not as good as that of 316L. If it is seawater, we must consider using titanium or titanium alloy materials. The chloride ion concentration of seawater is relatively high, and only titanium alloy materials can satisfy.
(2) Acid. If the concentration of dilute sulfuric acid is less than 10% and the temperature is lower than 50℃, stainless steel 316L can be used. If it is greater than that, Hastelloy should be used. The same principle applies to phosphoric acid and hydrochloric acid.
(3) Oil. General equipment lubricating oil and hydraulic oil are made of stainless steel 304. High temperature heat transfer oil needs to consider high temperature resistance, we use 316L material.
(4) Steam. For steam conditions, we generally choose 316L in the south because the temperature of steam is generally above 120°C. Many manufacturers consider the cost-effectiveness and choose 304 material. After a long time, the plates of the plate heat exchanger are basically likely to be deformed.