Which is better for compressed air heat exchange tubes: low-fin tubes or high-fin tubes?
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I have two questions. In compressed air energy storage power plants, the shell side of the heat exchanger is exposed to air at a temperature of around 400°C. To reduce equipment costs, finned tubes are being considered; are low-fin tubes better or high-fin tubes better? Downstream of the heat exchanger are an air turbine and an air compressor. Tests revealed that the surfaces of the low-fin tubes contained oil after processing, and this oil could not be removed completely, which might affect the operation of the turbine and compressor. Is there any way to thoroughly clean the oil from the surfaces of these low-fin tubes?
Regarding the first question, in general, high-fin tubes have a higher heat transfer efficiency than low-fin tubes, because high-fin tubes have a larger surface area and thus more heat transfer surface. In a high-temperature environment of 400°C, it is better to choose finned tubes, but care must be taken to select a material that meets the temperature requirements. Regarding the second question, if there is oil contamination on the surface of the low-fin tubes, cleaning solutions and detergents can be used for cleaning. It is also possible to consider using materials that are less likely to produce oil stains, such as stainless steel. Furthermore, for equipment such as air filters and compressors, it is advisable to carry out filtration in advance to prevent oil contamination from entering the equipment. .
Does a low-fin tube have a larger heat exchange area per unit weight than a high-fin tube?
First, the issue of impurities and oil in the gas medium must be addressed. When selecting a heat exchanger, parameters such as pressure, temperature, heat exchange area, and volume need to be taken into consideration. When the volume is constant, the higher the heat transfer efficiency, the better. But the allowable process conditions must be taken into account. Chemical methods are mostly used to clean heat exchangers. For reference.