Heat exchange area of the heat exchanger
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Is the heat exchange area of the heat exchanger sufficient, and how should it be calculated? What approach should be used for the calculation?
Using the basic equation for heat transfer, namely: Q=K*F*A*ΔT, where Q represents the heat transfer amount, K is the overall heat transfer coefficient (which depends on the heat transfer medium as well as the material of the heat exchanger), F is the temperature difference correction factor, A is the heat transfer area, and the last term represents the logarithmic mean temperature difference. It is recommended that the original poster take another look at Principles of Chemical Engineering.
Solve this problem using the knowledge from the chapter on heat transfer in chemical engineering principles. The thermal load of a heat exchanger is equal to the amount of heat transferred by the heat exchanger, Q = K A ΔTm. First, calculate the thermal load of the heat exchanger based on the temperature and flow rate of the heat transfer fluids: http://hgyl.ccut.edu.cn/old/section4/cr.fomulas.files/crf4-20.bmp. Here, K represents the overall heat transfer coefficient, and ΔT represents the temperature difference for heat transfer. Using these values, it is possible to calculate the heat transfer area A; this value can then be compared with the actual heat transfer area of the heat exchanger to determine whether it is sufficient
Based on the basic heat transfer formulas in chemical engineering principles, the heat transfer coefficient is assumed; after determining the heat exchange area, the assumed value of the heat transfer coefficient is then checked to see if it is reasonable. If it is greater than or less than a certain range, it should be recalculated.
The original poster had better take another look at the textbook on principles of chemical engineering
There are various methods for calculating the heat exchange area of plate heat exchangers; many parameters are related to the type of plates used, and these values are determined through experiments, allowing for an approximate calculation. 1. Determine the heat load. 2. Assume the outlet temperature on one side. 3. Calculate the logarithmic mean temperature difference. 4. Generally, the thermal conductivity of plates is greater than 3000. 5. Select a coefficient based on whether counterflow or co-flow operation is used, to ensure safety. In general, liquid-liquid heat exchange is simpler to calculate than vapor-liquid heat exchange. Reputable manufacturers usually have specialized calculation programs available. You can also incorporate a constant temperature control system.
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