Calculation of heat exchange area for shell-and-tube heat exchangers
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Could the experts here help calculate the heat exchange area for two heat exchangers? 1. For the tube side, it uses natural gas; the operating pressure is 0.8 MPa, with inlet and outlet temperatures of -40/5°C and a flow rate of 7174 KG/h. The shell side uses circulating hot water, with an operating pressure of 0.3 MPa and inlet and outlet temperatures of 80/60°C. 2. The tube side contains natural gas, with a working pressure of 4.0 MPa; the inlet and outlet temperatures are -40/5°C, and the flow rate is 7174 KG/h. The shell side contains circulating hot water, with a working pressure of 0.3 MPa; the inlet and outlet temperatures are 80/60°C.
Please refer to the Principles of Chemical Engineering, Chemical Engineering Handbooks, and Chemical Engineering Design Handbooks
In both cases, the heat load is the same and the logarithmic mean temperature difference is the same; the size of the heat exchange area depends on the degree of turbulence on the natural gas side of the tube side. Assuming that K is controlled by the tube side, in Case 1, K is 200 W/m2/K, while in Case 2, K is approximately 100*(0.8/4)^2 = 8. Therefore, the heat exchange area required for Case 2 is 25 times that of Case 1. The above are only estimates, as the actual situation is likely to be different and further calculation is required.