The design pressure issue of heat exchangers
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The unit is equipped with numerous heat exchangers, and there is one issue that isn’t clear: it relates to the design pressure of these heat exchangers. For example, consider a certain heat exchanger in which the shell side contains steam, with a design pressure of 0.45 MPa, while the tube side contains acidic gas, with a design pressure of 0.15 MPa. As for this issue of design pressure, why is it different for the same heat exchanger? Does a shell side design pressure of 0.45 MPA mean that the shell side becomes dangerous if the pressure exceeds this value? Please share your thoughts, thank you, extra points!
The shell side and the tube side are two separate chambers that carry different fluids; their operating pressures are different, and therefore their design pressures also differ. The operating pressure must not exceed the design pressure.
Because the pipe bank and the course belong to two different chambers, their design pressures and operating pressures are different. Regarding your concern that going a little above the design pressure might be dangerous, actually going just a little over it isn’t a problem, as the maximum operating pressure is slightly higher than the design pressure
A heat exchanger is a special pressure vessel with a tube side and a shell side. There are different design pressures and operating pressures. As you said, if the pressure in the shell side exceeds 0.45 MPa, it is dangerous; this constitutes overpressure operation. An accident may not occur immediately, but it is still a dangerous operation. There is overpressure in the shell side; as for the tube side, it is subjected to external pressure, which can cause plastic deformation, but fracturing is not necessarily inevitable. But there is overpressure in the shell side; it’s an internal pressure. If the pressure exceeds the limit by a significant amount, an explosion will occur, which constitutes a equipment failure