Summary for the H2 example simulation

Shell and tube heat exchangers often have a wide pressure difference between their fluids. If the MAWP (maximum allowable working pressure) of the low-pressure side is less than 10/13th of the high-pressure side, the low-pressure side may exceed its test pressure after a tube rupture.

API Standard 5211 section 4.4.14 recommends transient analysis for heat exchanger tube rupture even if protected by a relief valve. This type of analysis is recommended in cases where the low-pressure side is liquid-filled and the high-pressure side contains a gas or a fluid that flashes across the rupture. The pressure spike may occur very fast, in the order of milliseconds, after the rupture.

Similarly, a tube rupture may over-pressurize adjacent piping as well.

The objectives of this simulation are:

• Estimate pressure spike in the low-pressure side of the exchanger.

• Estimate the pressure spike in the adjacent piping.

• Determine the effectiveness of a relief valve which must open in response to the pressure spike.

The following figure illustrates the tube rupture simulation as modeled in AVEVA Process Simulation.