Quench Oil Isolation to Prevent Incidents

Quench oil can present many challenges when it comes to isolating and clearing equipment for maintenance. Ethylene plants designed to crack liquids contain equipment in quench oil service that requires frequent maintenance such as feed preheaters, dilution steam generators, process water preheat, quench oil pumps and filters, and quench fittings.

Quench oil presents challenges to operators during LOTO and clearing due to its physical properties; it can contain solids, is viscous, and has a high pour point.

Failure to isolate and clear this equipment correctly has led to significant process safety incidents and injuries.

This paper will review quench oil physical properties, highlight incidents related to quench oil loss of containment, discuss criteria for selecting isolation valves, and make recommendations for design best practices.