Features of plate heat exchangers

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The characteristics of plate heat exchangers are compared with those of shell-and-tube heat exchangers. Below, the author will explain in detail what features plate heat exchangers possess: 1. High heat transfer coefficient. Although shell-and-tube heat exchangers have high structural strength, they are somewhat deficient in terms of heat transfer; as the heat transfer fluid flows through the shell side, it passes through bypass paths between the baffle plates and the shell, between the tube bundle and the shell, and between the baffle plates and the heat transfer tubes, which prevents thorough heat exchange. In contrast, plate heat exchangers do not have bypasses, and the unique corrugated shape of the plates enables strong turbulence to occur at lower flow rates; as a result, their heat transfer coefficient is high, typically 3 to 5 times that of shell-and-tube heat exchangers. When performing the same heat exchange task, the heat exchange area of a plate heat exchanger is only 1/3 to 1/4 that of a shell and tube heat exchanger. 2. In terms of floor space, plate heat exchangers have a compact structure; their heat exchange area per unit volume is 2 to 5 times that of shell-and-tube heat exchangers. Additionally, when performing maintenance on shell-and-tube heat exchangers, it is necessary to reserve a large area for such work, whereas plate heat exchangers require only a smaller area for replacing the plates. Under the same heat exchange requirements, the floor area required by a plate heat exchanger is only 1/5 to 1/10 of that required by a shell and tube heat exchanger. 3. In shell-and-tube heat exchangers with a large logarithmic mean temperature difference, the fluid flows in a cross-flow manner, and a smaller correction factor is used for the logarithmic mean error. In plate heat exchangers, when the fluid flows in co-current or counter-current mode, the correction factor for the logarithmic mean temperature difference can reach up to 0.95. 4. Low investment cost: Plate heat exchangers have a simple structure, and in terms of material costs, their price is much lower than that of shell-and-tube heat exchangers. 5. The fouling coefficient is low: In plate heat exchangers, the fluid flows violently and turbulently, making it difficult for impurities to accumulate. The flow dead zones between the plates are small, the heat exchange surfaces are smooth, and there is little accumulation of deposits, which facilitates cleaning. Therefore, the fouling coefficient of plate heat exchangers is much lower than that of shell-and-tube heat exchangers. 6. Multiple media heat exchange is possible: Plate heat exchangers can be equipped with intermediate partitions, allowing for heat exchange between three or more media, whereas shell-and-tube heat exchangers cannot facilitate heat exchange among multiple media. 7. Easy to change the heat exchange area and flow configuration: To increase or decrease the heat exchange area, it is sufficient to add or remove plates. If there are new heat exchange conditions, simply change the process combination. 8. Cleaning is convenient – all that is needed is to remove the clamping bolts of the plate heat exchanger, loosen the plate bundle, and take out the plates for cleaning. This makes it very convenient for processes that require frequent cleaning of heat exchange equipment.