Explosion and Fire in a Chemical Plant Producing Aromatic Hydrocarbon (959)

A gaseous mixture of hydrogen (H2), methane (CH4) and ethane (CH3-CH3) at 54 bar was cooled in a heat exchanger upstream of a hydrogen purification system. The accident started with a double explosion followed by a fire.The heater used to regenerate the adsorbent beds of the purification unit had been repaired a few hours earlier, but the automatic heating mode had not been activated upon restart. Therefore, two regeneration cycles had been carried out cold, causing an overload of the adsorber and the fouling of the heat exchanger.