In August 1999, an explosion in an MDEA storage tank at a Nitrogen Products plant in Alaska propelled the tank off its base and into the air. The tank landed on an adjacent air-cooled heat exchanger filled with synthesis gas. The impact of the tank on air-cooled heat exchangers initiated a second explosion and fire. Three operators received minor injuries.
Reverse-flow phenomena caused process gas to enter the storage tank, ignited by an unknown source. The plant installed check valves in the MDEA system and equipped the storage tank with an inert gas-blanketing system. It conducted PHA on the MDEA system and revised operating procedures to improve operator awareness of reverse-flow and other startup/shutdown conditions.
