Modeling Pressure Relief Devices Mounted on a Common Inlet Manifold

Large equipment items, such as distillation column systems, compressors, or major pressure vessels, are commonly protected by multiple pressure relief devices mounted on a common inlet manifold. In selecting this type of design, the potential exists to inadvertently overlook the flow characteristics associated with such a common inlet manifold.

ioMosaic has developed a methodology to effectively model flow through multiple pressure relief devices mounted on common inlet manifolds. This approach ensures accurate representation of flow through each pressure relief device while avoiding the potential pitfalls of a simplified approach.

Large equipment items, such as distillation column systems, compressors, or major pressure vessels, are frequently protected by multiple pressure relief devices. Often, multiple pressure relief devices are needed to provide adequate relief capacity to handle the large relief flowrates from overpressure scenarios affecting these large systems. Additionally, the set pressures of these relief devices can be staggered to better address varied relief requirements and to improve pressure relief device flow stability.

It is also fairly common practice for these multiple relief devices to be mounted on a common inlet manifold. Installing these devices on such a piping manifold can provide easier access for maintenance and inspection by locating these on a platform or deck, as well as providing the strong structural support needed for multiple heavy relief devices.

However, in selecting this type of design, the potential exists to inadvertently overlook the flow characteristics associated with such a common inlet manifold. Modeling the flow hydraulics to multiple relief devices through such a manifold is more complex than most companies realize, and the potential exists to overlook the impact that the inlet manifold has on the stability of each component relief device.

This paper presents a methodology to effectively model flow through multiple pressure relief devices mounted on common inlet manifolds. This approach ensures accurate representation of flow through each pressure relief device and intends to avoid the potential pitfalls of a simplified approach.