Dynamic Analysis of Heat Exchanger Tube Rupture Scenario Case Study


The Challenge

An American energy company with multiple refineries in California and other locations in the U.S. required some complex dynamic analysis. ioMosaic was to evaluate dynamically a tube rupture overpressure scenario for several heat exchangers systems.

The main challenge encountered during this project was to accurately track the vapor/liquid interface. In order to do that, it is critical to define the correct initial liquid volume, use a small-time step during the dynamic simulation, and split the downstream piping in as many equal-volume sections as possible.

Our Approach

The analysis was conducted using Process Safety Office® SuperChems™. Detailed pressure relief valve reports and supporting documentation were managed with Process Safety Enterprise®.The tube rupture overpressure analysis for each system was divided into three main steps:

  • Estimate the flow from the broken high-pressure source
  • Calculate the initial pressure pulse caused by the formation of the first gas bubble on the low-pressure side and the liquid acceleration
  • Study the transient pressure development in the low-pressure side as the liquid is expelled and the high-pressure gas expands into the low-pressure side

Shell internal stress vs. failure stress at 2/3 UTS.

Shell internal stress vs. failure stress at 2/3 UTS

Source: G.A. Melhem, Ph.D., “Realize Better Risk Characterization of STHE Tube Failure Scenarios Through Relief Systems Dynamics Modeling”, ioMosaic Whitepaper (2018).

The Benefits

The deliverable for each system analyzed was a report illustrating the following results:

  • Pressure profile based on the liquid being first pushed out of the low-pressure side, and then the expanding gas continuing to push the liquid out of the piping and gas out of the rupture pin
  • Vapor-liquid interface and average slug velocity in the piping
  • Mass flow rates profiles of the different species
  • Pressure profile throughout the liquid filled piping at the maximum pressure reached
  • Flow impulse profile of the flowing liquid

This detailed report provided the client with a comprehensive analysis of the system design and process operations data.

Learn More

Our mission is to help you protect your people, your plant, your stakeholder value and our planet. To learn more about how we can help you manage risk, call us at 1.844.ioMosaic.