Analysis of The Impact of Fouling and Non Cleaning On Plate Heat Exchangers

1. Scaling deteriorates the heat transfer condition of plate heat exchangers, causing overheating of the heat transfer surface and causing safety accidents such as bulging, cracks, and tube explosions.

Due to the poor heat transfer ability of dirt, the temperature on the high-temperature side of the equipment cannot be quickly transmitted to the low-temperature medium after scaling on the heat transfer surface, causing the metal wall temperature of the heat transfer surface to continue to rise and reach the creep temperature. When the metal wall temperature reaches or exceeds the creep temperature, the mechanical properties (such as toughness and plasticity) of the metal obviously deteriorate, and the tensile strength and compressive strength greatly decrease, making it easy to be burned and deformed at high temperatures. When the equipment is operating under pressure, the overheating tube wall experiences safety accidents such as bulging, cracking, leakage, and even tube explosion due to a significant decrease in compressive strength.

2. Scaling can cause corrosion damage under the scale, causing equipment perforation and leakage, shortening the service life of the equipment. The density, thickness, and chemical composition of the scale formed on the heat transfer surface of the equipment are usually uneven. This uneven dirt coverage causes electrochemical non-uniformity on the metal surface, which is easy to trigger electrochemical corrosion reactions. Scaling can also cause certain corrosive components such as H+, OH -, Cl -, Mg 2+, S 2-, etc. in the water to accumulate on the metal surface beneath the scale and produce chemical corrosion reactions. The result of corrosion is that local metals are damaged and thinned, and corrosion can penetrate the equipment steel plate, causing equipment leakage, damage, and even failure, thereby increasing equipment maintenance costs. When corrosion is severe, equipment can be scrapped in advance.

3. Scaling can cause unstable production processes, affect the quality of plate heat exchangers, and cause quality accidents. After equipment scaling, due to a decrease in heat transfer efficiency, the heating or cooling conditions of the equipment will deteriorate, which will affect the production process. Instrument indications will malfunction, temperature and pressure indicators will deviate from the process design requirements, equipment operating parameters will change, and the production process will be unstable. Eventually, the output and quality of the product will decrease, and the defect rate will increase. In severe cases, production may be interrupted, resulting in unplanned shutdowns.