Fire at a Desulfurization Unit (735)
Hydrogen gas leaking from drain pipes in a hydrodesulfurization plant: There was a hydrodesulfurisation plant which had a recycle hydrogen compressor fitted with a suction rectifier. Hydrogen gas gushed out through a hole made by corrosion at the drain pipe on the suction rectifier. The process condition (45C and 3.7Mpa) made atmosphere causing hydrogen sulfide-ammonia corrosion in the drain pipe which consisted of about 10m horizontal parts and an upward outlet. This upward outlet made it impossible to drain out completely. Furthermore, steam insulation also contributed to the corrosion.