On July 1, the ExxonMobil gasoline pipeline in Montana that travels through
Yellowstone National Park suffered a major leak from a broken pipe and
spilled into the Yellowstone River.
A couple of questions arise.
First, why did it take so long to isolate the broken line? Indicators
showed low pressure in the line at 10:41 pm, a classic indication of a leak.
At 10:47 pm, ExxonMobil began the shutdown process. The pipeline at the
Yellowstone River was "fully isolated" at 11:36 pm. Typical time to close
for an automatically actuated control valve is on the order of a minute or
less. Why the delay?
Second, is ExxonMobil using online corrosion detection sensors from any
one of a number of vendors to monitor corrosion that could cause a break in
the pipeline? With a full-fledged SCADA control system in place, you'd
think they'd want to sense the presence of corrosion products in the pipe.
Joe Weiss
