Fire in a refinery plant

The event occurred in an alkylation reactor. Due to the rupture of a pipe (probably due to material failure), a power failure took place and the plant was automatically put in hot-stand-by mode. This implied the cut out of fuel feed and energy supply. The plant was gradually cooled down.
After about half an hour, for reasons not yet clarified, a fire started at the outlet of the alkylation reactor.

The INITIATING cause was the rupture of the pipe feeding into the reactor, probably due to material failure.
How this relates to the development of a fire later is unknown. The investigation report is not available.

alkylation reactor, feeding pipe

The accident occurred during normal operation of the plant. However, fire started after that a shutdown caused by the failure of a pipe.

DESCRIPTION OF THE PROCESS
An alkylation unit is one of the many conversion steps taking place in petroleum refineries. It converts isobutane and low-molecular-weight alkenes (primarily a mixture of propene and butene) into alkylate, a high octane gasoline component. The process occurs in the presence of an acid as catalyst. The feeds contains as well non-condensable gases such as ethane and hydrogen.
(from Wikipedia, https://en.wikipedia.org/wiki/Alkylation_unit)

The total establishment and the potential directly involved inventories of hydrogen, methane, benzene and toluene has been estimated in about 10,000 Kg. This figure refers to the whole amount involved in the accident. No data are available about their single amounts.
No people injured. The cost of the material damages estimated between 2 to 5 millions of Deutsch Marks.

Emergencies actions were necessary only inside the plant.

The emergency depressurization of the plant was activated. In order to minimize the amount of flammable substances involved, the isolation of various sections of the plant was carried out. Nitrogen purging of the system was carried out. The adjacent installations were protected by applying cooling water.

The fire was extinguished by the intervention of operators, the plant fire brigade and the local fire brigade. The fire fighting water was collected in a basin and disposed for treatment in the biological waste-water treatment plant of the establishment. Ambient air monitoring inside the establishment revealed no presence of hazardous substances in the environment.