Overview

The catalyst in a dehydrogenation reactor, which was usually operated under a hydrogen atmosphere, was changed while the reactor was isolated from the peripheral equipment by closing a 20-inch remotely controlled valve. The hydrogen pressure in the peripheral equipment was set at 20 KPaG, and the reactor was opened to the atmosphere. Anticipating some hydrogen leakage, suction from the piping was accomplished with a vacuum device and, nitrogen sealing was performed. When the piping connections were restored after changing the catalyst, flames spouted from the flange clearance and two workers were burned. One cause of the fire was poor management of the catalyst replacement process.

Incident Synopsis

A catalyst exchange was carried out in a dehydrogenation view more

Incident Synopsis
During transfer of liquid H2 from a commercial tank trailer to a receiving vessel, a leak developed in a bayonet fitting at the trailer/facility connection. The leak produced liquid H2 spray which enveloped the rear of the truck where the hand-operated shutoff valve was located. Emergency trained personnel, wearing protective clothing, except for proper shoes, entered the area and shut off the flow control valve. Reentry personnel suffered frost bite of their feet when shoes became frozen to the water-wetted rear deck of the truck.

Cause
A loose hose flange connection allowed leakage of cold fluid through the lubricated bayonet seal. This allowed cold fluid to contact and shrink the 'O' ring seal (made of Buna-N rubber), thus permitting view more

Incident Synopsis
While disconnecting a liquid H2 fill line from a liquid H2 trailer, liquid H2 escaped, burning a second man who was holding the hose. The man was burned on his hands and on his stomach.

Cause
The liquid H2 shut off valve was partially open, but both men assumed it was closed. Prescribed clothing was being worn.