Fire in a plastics production plant

Fire on a filter of an autoclave.
The event occurred in a plant for the production of plastics. After catalytic synthesis of amines, the filter of the autoclave was taken out for cleaning. During the removal, the fire started.
The fire was extinguished with water jets and water injection into the reactor vessel. The damages were very limited.

The event was caused by the presence of hydrogen at the top of the reactor, which was also in contact with the filter because the valve aiming at isolation the filter had remained open. The ignition of the hydrogen was probably due to the presence of the catalyst, which is pyrophoric when dry.

The INITIATING cause was the presence of hydrogen in the filter. The intermediate cause is the failing to close the valve supposed to isolate the filter from the content of the reactor.
A CONTRIBUTING OR ROOT CAUSE reported was related to the procedure in place to prepare the filter for dismantling: it must be cleaned-up under water and then dried under nitrogen, to avoid the too intensive drying of the catalyst which can cause the production of sparks. In that case, the drying by nitrogen purging was longer than foreseen.

,valve, filter, autoclave for the synthesis of plastic

After catalytic synthesis of an amine, the filter the autoclave was taken out for cleaning.

Only the filter's valve and manometer were damaged.

The fire remained localised on the filter. The operators did not succeed in extinguishing the fire with water jets. The introduction of water directly at the entrance of the filter while closing the exit valve allowed to extinguished the fire.

The following actions were taken:
1) reduction of the phase of drying of the catalyst by nitrogen;
2) maintaining the filter continuously under water during the dismantling;
3) emptying all the spaces containing the catalyst;
4) installing a hydraulic safe-guard for the case that the isolation valve does not function;
5) re-training personnel on the procedural instructions.