Regarding the issue of increasing the withstand test pressure
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Everyone, when the design pressure of the tube side is higher than that of the shell side, why is it necessary to raise the pressure test requirement for the shell side to be on par with that of the shell side itself?
It is intended to prevent leakage at the connection between the heat exchange tubes and the tube sheet to the shell side when pressure is applied from the tube side, so that such leakage is not easily detected
During normal production, if there is a break and leakage in the tube side, will it cause overpressure in the shell side? For reference.
It’s not necessarily the case; as long as the quality of the connection at the pipe outlet can be ensured, and sufficient pulling force is available, then the shell-side safety valve will have enough margin. If the pressure difference between the tube side and the shell side is particularly large, this will result in a very thick shell side.
Analyze each device individually; it’s not necessary to raise all of them to the same level.
This design unit must specify it; here is the source: GB/T 150-2011 4.6.1.7
The standards do not require that the test pressure in the shell side must be increased to match that in the tube side; raising the pressure for the stress test is merely one method. This approach is not appropriate when there is a large difference between the pressures on the two sides. Typically, a stress test for the shell side is combined with an ammonia leakage test. The purpose of doing this is to test the quality of the pipe fittings.
Generally, the test pressure of the tube side is used to verify the pressure-bearing components on the shell side. If the requirements are not met, and the difference is not significant, it may be possible to increase the wall thickness of the shell accordingly. If the difference remains large, then the maximum allowable test pressure for the shell side must be used; thereafter, a leakage test on the shell side is conducted as a supplementary check.