Case Study: BP Texas City Explosion 23 March 2005
The increase in average column temperature reduced the density of the hydrocarbon liquid, significantly increasing the liquid level. As the entire column approached the boiling point of the liquid, the vapor bubbles accumulated instead of being rapidly condensed. The resulting increase in volume from vaporization caused the liquid at the column top to overflow into the vapor line.
Safety Relief Valves Open
As the liquid filled the overhead line, the resulting hydrostatic head in the line increased. The tower pressure (which remained relatively constant) combined with the increased hydrostatic head and exceeded the set pressures of the safety relief valves. The valves opened and discharged liquid raffinate into the raffinate splitter disposal header collection system.
Hydrocarbon Liquid Flows Into Collection Header