Protecting process systems from overpressurization is a critical task in the chemical process industries (CPI), and rupture disks and safety relief valves are routinely used for this purpose. In certain situations, using rupture disks in combination with safety relief valves offers advantages that can increase safety and lower costs. The advantages include a significant lengthening of the service life of the relief valve, as well as prevention of process leakage.
What considerations should be made when combining devices? And how can you decide when the combination is appropriate versus when it may not be useful?
Reasons to combine the two
When overpressurization occurs in situations where rupture disks are combined with safety relief valves, the disk bursts and a valve release follows. Once the pressure drops to a safe level, the safety valve reseats itself and continues to protect the system (Figures 1 and 2). There are several situations in which using the two systems together can lead to significant benefits.
Isolation of relief valve. Rupture disks can isolate a safety relief valve from process fluids and materials, so that, under normal operating conditions, the safety valve does not encounter the process chemicals. Since…