Washington — Pressure relief valves, rupture discs and other equipment designed to prevent overpressurization within chemical vessels must always function properly, the Chemical Safety Board is reminding industry stakeholders.
The message is part of an update of CSB’s investigation into a November incident at the Givaudan Sense Colour facility in Louisville, KY. A batch reactor vessel exploded after pressure built up during production of caramel coloring for a food product. The blast killed two workers and seriously injured three others, in addition to causing extensive property damage to the facility and surrounding community.
CSB determined that internal pressures and temperatures each exceeded the vessel’s capacity design limits. The agency says the batch reactor had a vent valve designed to automatically open and close to control batch reactor pressure. When the pressure and temperature within the reactor began to rise, however, the valve may not have opened despite commands to do so.
In the investigation update, CSB says that process fluid flows through the vent opening when the ball valve in the vent aligns with attached piping. If the opening is perpendicular to piping, the flow of process fluid is stopped.
“This massive explosion should not have happened,” CSB Chair Steve Owens said in a press release.
The investigation is ongoing, the agency says, adding that “complete findings, analyses and recommendations, if appropriate, will be detailed in the CSB’s final investigation report.”
