INVESTIGATION OF A STEAM EXPLOSION IN A PETROLEUM-PRODUCT STORAGE TANK

An explosion occurred in a petroleum product storage tank! at a refine ry. The liquid petroleum product was a heavy oil used as an asphalt ex tender. There were no injuries, but the cleanup was costly. The storag e tank was one of several which received the product stream from a deh ydration unit. The accident occurred shortly after the refinery was br ought back on-line following a shutdown for scheduled maintenance. Thi s was the first incident of this kind to occur at this facility. Analy sis of the process data and eyewitness observations indicated that the dehydration tower, which was supposed to be maintained at a minimum o f 100 degrees C during the shutdown, was allowed to drift below 100 de grees C for an unknown period of time. This deviation enabled liquid w ater to enter the storage tank three operational factors contributed t o the accident. Corrective actions were recommended to prevent a recur rence of a similar incident.