An explosion occurred in a hydrogen liquefier/purifier commissioned in 1987, after it had previously operated safely for many years. The explosion took place in the nitrogen cold box section of the hydrogen liquefaction process in an activated carbon cold adsorber vessel. Process records showed that the explosion occurred at the beginning of the regeneration phase of the activated carbon adsorber. When the explosion took place, the outlet temperature of the activated carbon bed was still at -190C. The force of the explosion was estimated from a mapping of the debris to be between 10 and 100 kg TNT equivalent.Activated carbon is a general term that covers carbon material mostly derived from charcoal. It has an exceptionally high surface area and can adsorb large quantities of gases. It view more