Question: In the design of an evaporator, what determines its height?
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As the title suggests: After performing the process calculations to determine the heat exchange area, how can one calculate the height of the evaporator? I’ve searched through many resources, but they only provide methods for calculating the inner diameter of the evaporator’s heater; no information on how to determine its height is available. Please advise those who know the answer! ! ! :dizzy:
1. Logically speaking, area is a concept that applies to a specific structure; without knowing the height (one of the structural parameters), how can there be an area? An area that does not correspond to a specific structure is surely an approximate and unscientific figure; I strongly disagree with this. 2. Height comes in two cases: in a dry evaporator tube, there is a gas-liquid separation space above the liquid ； In a wet evaporator, the liquid essentially fills the heat exchange tubes, while gas-liquid separation takes place outside the evaporator. So the former is higher than the latter. The height of the heat exchange tubes generally does not exceed 2.0 m.
First of all, thank you very much for your help. The heat exchange area is indeed only an approximate value; it is provided to the manufacturer after performing process balance calculations, and the final heat exchange area is subject to the manufacturer’s decision. What I’ve come across here are mainly falling film evaporators, and the longest tube length I’ve seen is 14 meters.
First, the evaporation method is selected based on the properties of the material, such as falling film, rising film, or forced circulation. Once the evaporation method is chosen, the specifications for the tubes are determined. The length is then obtained. Then, based on the amount of evaporation, the number of pipes required can be determined, and thus the diameter can be found.
After determining the evaporation area and pipe specifications, only the total pipe length can be determined. Is it true that the number of heating tubes needs to be calculated based on the selected length of the tube?
No, the length of the tube is determined based on the evaporation method. For example, the tube lengths used in falling film evaporation and forced circulation evaporation are different.