Marcio Donnangelo and Marcelo Dultra presented on continuous pressure relief valve (PRV) and rupture disk (RD) monitoring for releases and leaks at the 4C Health, Safety & Environmental conference. Marcelo described a PRV. They are mechanical devices, disconnected from the control system that operate when a set pressure is exceeded. They should never operate in […]
Imagine you have been tweaking and tuning one of your control loops and have the perfect PID [proportional-integral-derivative] settings. Everything is working great for several months until it isn’t. Chances are that it’s the part of that loop doing all the manual work to keep the process running smoothly—the control valve. A poorly performing control […]
Author: Pete Sharpe An ethylene plant has a number of very large, very critical compressors which will cause the entire plant to shutdown if they ever trip. The cracked gas compressor increases the entire cold-side feed from around 3 psig to ~475 psig, typically through 5 stages. The two refrigeration compressors are the next biggest […]
For many applications, such as emergency shutdowns (ESD), on-off quarter valves with electric actuators are the best fit. In the event of loss of power, some type of fail-safe mechanism may be required to bring the valve into an open or closed position as required by the process. These applications are typically found in the […]
A safety instrumented function (SIF) in a safety instrumented system (SIS) contains a sensor, logic solver and final element. All must function properly in the event of a safety demand to take the process into a safe state in coordination with other SIFs. The final element consists of several parts including the isolation valve, actuator, […]
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