A straight run of eight-inch-diameter line carrying hot oil from the high pressure separator to the low pressure stripper in a refinery hydrodesulfurizer fractured circumferentially in the parent metal in the heat zone about 1.5 inches from a weld. Hot oil at 700 psi and 650°F sprayed across the roadway into the hydrogen units where ignition occurred. An intense fire around the pipe rack in the hydrogen plant caused a 16-inch-diameter gas line to rupture, adding a second blow torch to the fire. More pipes ruptured with explosive force in adjacent areas. The fire resulted in a crash shutdown of the entire 600,000 bbl/d refinery. After six and a half hours, the fire was extinguished. Damage was extensive. The three hydrogen plants and the four hydrodesulphurization (HDS) units were heavily damaged or destroyed. Before the loss, the line which failed was judged as having excessive vibration. It is believed that the hot oil line failed due to fatigue, considered, in turn, to be largely due to hydrogen embrittlement.
[ Property Damage $75 Million. Estimated Current Value $180 Million ]
Image credit: PDVSA