(66b) Selection of Pressure Protection Disposal Systems for Atmospheric Discharges

Discharging highly hazardous chemicals (HHC) to the atmosphere remains a major challenge for refineries with atmospheric pressure protection and blowdown systems.  The potential consequence of discharging HHC to the atmosphere is determined based on key factors including, but not limited to, chemical type, estimated flow rate, concentration, discharge phase, location, and operating procedures.

In recent years, several fatal incidents have proven the need to eliminate HHC disposal to the atmosphere and that other means of safe disposal should be evaluated.  The evaluation of other safe disposal systems should be based on good engineering understanding of the nature of the challenge.  Therefore, potential scenarios, including human error, that may result in system overpressure should be identified and used as a basis to ensure that the technology and equipment used for disposal is appropriate for all credible scenarios.

In this presentation, a decision-making approach to determine safe disposal system based on combined understanding of atmospheric discharge impact and possible alternative discharge locations will be discussed.  This approach provides process operators and managers with a tool to layout an engineered path leading to a recommended discharge location.