The reason why the plate heat exchanger fouls is very simple. The first point is that the environment where the heat exchanger equipment is running is a major cause of fouling. For example, some heat exchangers are installed in the workshop. There is a lot of dust in the workshop, which will become scale after a long time. Some heat exchangers are installed in the water for a long time, and the suspended solids in the water are also easy to scale. Similar to this The situation will produce scale. What are the common types of scale,
1) Particle fouling: The accumulation of solid particles suspended in the fluid on the heat exchange surface. This kind of fouling also includes the sedimentation layer of larger solid particles formed by gravity on the horizontal heat exchange surface, that is, the so-called sedimentation of fouling and other colloidal particles.
2) Crystallization fouling: The deposits formed by the crystallization of inorganic salts dissolved in the fluid on the heat exchange surface usually occur during supersaturation or cooling. Typical fouling such as calcium carbonate, calcium sulfate and silica fouling layer on the cooling water side.
3) Chemical reaction dirt: dirt produced by chemical reaction on the heat transfer surface. The heat transfer surface material does not participate in the reaction, but it can be used as a catalyst for the chemical reaction. 4) Corrosive fouling: Fouling caused by corrosive fluid or fluid containing corrosive impurities that corrodes the heat exchange surface. Generally, the degree of corrosion depends on the composition, temperature, and pH of the fluid being processed.
4) Biological fouling: Except for seawater cooling devices, general biological fouling refers to microbial fouling. It may produce slime, which in turn provides conditions for the propagation of biological fouling, which is very sensitive to temperature. Under suitable temperature conditions, biological fouling can generate a considerable thickness of fouling layer.
5) Fouling: Fouling formed by the solidification of fluid on the supercooled heat exchange surface. For example, when water is below the freezing point, it solidifies into ice on the heat exchange surface. The uniformity of temperature distribution has a great influence on this kind of fouling.