There is a significant difference between the EDR and HTRI calculation results
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The company needs to design a condenser; since the steam is dirty, it must flow through the tube side. The steam flow rate is 1474 kg/h, the temperature drops from 143°C to 45°C, the refrigerant is circulating water with its temperature rising from 30°C to 35°C. The operating pressure on the tube side is 3.98 bar, while the operating pressure on the shell side is 2 bar. Using EDR, the circulating water flow rate was calculated to be 35,482 kg/h, with a flow velocity of 0.57 m/s in the shell side and 0.82 m/s in the tube side; however, the calculation indicated that the physical properties did not match. A colleague used HTRI to calculate that the circulating water flow rate is 176,890 kg/h, with a flow velocity of 1.21 m/s in the shell side and 0.03 m/s in the tube side. I don’t know why there is such a large difference in the circulating water volume? Based on the results obtained using HTRI, the flow velocity in the tube side is too low, leading to easy clogging, as well as a low thermal conductivity. I’m not sure if the circulating water volume calculated by EDR is correct?
The water volume has nothing to do with your heat exchanger; it’s just a matter of heat balance, right? If it doesn’t work, it means one of the physical properties is incorrect; try calculating it manually
Thank you very much. After doing some calculations manually, it turns out that the HTRI value is quite accurate; EDR does not seem to take the latent heat of vaporization into account. What property values would be appropriate for steam condensation at an operating pressure of 4 kilograms?
Do you confirm that for your input, the import logistics is by gas phase? If it is in the gas phase, EDR should not fail to account for the vaporization latent heat.
Did you manually add the data to your EDR? Generally, if the calculations are done in Aspen and then the results are imported directly, this problem shouldn’t arise. As for the properties of water vapor, there are only two or three methods available; any of them will give similar results. Alternatively, you can change the amount of cold water in EDR, perform the calculations, and check whether the gas-liquid ratio after vapor condensation is the same as that in HTRI (for heat exchangers with similar structures)
Yes, the data in my EDR was added manually; I’ll try importing it from ASPEN
That’s incorrect; the operating pressure was entered wrong. Moreover, you shouldn’t be able to control the pressure of the incoming steam. What’s the purpose of this thing anyway? Is there such a way of using it?