This document was originally prepared following the explosion of an activated carbon cryogenic purifier cooled by liquid nitrogen in helium service in Europe.
In addition to this explosion EIGA is aware of three other similar incidents and one that occurred in an activated carbon cold adsorber in the nitrogen cold box section of a hydrogen liquefaction process.
Each purifier had previously operated safely for many years. In all cases it is believed that condensation of an oxygen enriched phase occurred and this reacted with the activated carbon adsorbent, resulting in an explosion.
This edition has been revised to reinforce and clarify the sections on condensed oxygen mixtures and oxygen analysis.
This document provides guidance on the safe operation of cryogenic activated carbon gas purifiers with particular reference on how to prevent explosions.
The document is intended to be used by those who are responsible for the design, operation and maintenance of activated carbon cryogenic purifiers.