Let’s use an example to discuss heat exchanger design
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High-pressure heater for power plants: Shell side, water at 0.8 MPA and 280 degrees Celsius; tube side, water at 7.8 MPA and 104–155 degrees Celsius, flow rate of 130 T/H
First step in the design: Determine the thermal balance by dividing the shell side into areas for superheated steam cooling, saturated steam condensation, and condensed water cooling. The heat transfer rate Q is determined to be 7041 KW, and the amount of steam required on the shell side is also determined; details on this are not covered here
In the second part, determining △t is still uncertain; feel free to come and discuss it
0.8MPA, 280 degrees Celsius – such water does not exist on Earth, but water vapor of this type does.
Therefore, the heat exchanger cannot be designed either.
I’m sorry for the mistake; it was superheated steam
For the shell side, a pressure of below 1.0 MPa is sufficient; there is no need for a superheating section – a condensation section and a hydrophobic section are adequate.
Whether a steam cooling section is needed should be related to the temperature difference at the feedwater side, right?
If no superheating section is provided, then the issue of average temperature difference arises: the superheated steam is at 280 degrees Celsius, while the saturated steam is at 170 degrees Celsius. Should this temperature difference be ignored?
For now, let’s not consider whether it is necessary to include an overheating section in the equipment. If steam superheating is not taken into account, then where does the average temperature difference come from? Should this average temperature difference for superheated steam at 280 degrees turning into saturated steam at 170 degrees be ignored?
It is recommended to consult Chapter 10 of the \"Technical Manual for Thermal Power Generation Equipment, Volume 4: Power Plant Systems and Auxiliary Equipment\".