Safe shutdown: The best-laid plan - Energy Factor
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Safe shutdown: The best-laid plan

Sep. 29, 2017

The process of shutting down a refinery can’t be simplified or cut short just because a historic flood is coming.

“You can’t skip steps,” said Kristy McCarty, lead of the environmental department at ExxonMobil’s Beaumont refinery and chemical plant in southeast Texas. “The shutdown process is built entirely with safety in mind, and each step, no matter how small it may seem, is crucial for doing it correctly.”

It was up to a large team of employees, including McCarty, to help refinery personnel safely shut down the entire facility—while minimizing environmental impacts—as Hurricane Harvey, one of the fiercest natural disasters ever to hit the U.S. Gulf Coast, approached.

With thousands of employees and the capacity to process more than 370,000 barrels of crude a day, the Beaumont refinery is a behemoth—among the largest refineries in the United States.

The process of shutting down such an operation is a delicate ballet of moving pieces, each step meticulously orchestrated so that all interconnected units work in tandem. It requires precise coordination and rehearsed communication among a dedicated team of professionals.

And one of the most important elements to consider during a shutdown is what to do with all the refinery’s “in-transit” streams.

“A refinery is constantly moving crude, refining it into different products,” McCarty said. “When that movement stops, it means that some gases that were in the middle of being processed are stopped in their tracks, now immobile.”

She went on to explain that the partially processed streams need to be collected from different stages along the refining path, and then safely disposed of, if they can no longer be used or safely stored.

The industry standard for that task is flaring. During flaring, excess gases are combined with supplemental natural gas, steam or air, and are burned off, producing primarily water vapor and carbon dioxide. You’ll often notice a flare at a refinery when units are shutting down or starting up,whether for routine maintenance or unplanned interruptions.

Flaring plays a critical role in protecting the operating units and pipes from over-pressurizing, and it also keeps nearly all of the refinery’s excess emissions from being released into the atmosphere.

“The most important part of a shutdown is ensuring the safety of our employees and neighboring communities,” McCarty said. “We do that by making sure that critical safety systems, like flaring, are working properly.”

The Beaumont refinery shutdown was a success. But before the team could reflect on a job well done, they began supporting the plan for ensuring a safe startup; indeed, the refinery has already begun producing fuels again, slowly but surely.

Tags: Hurricane, safety, Harvey, Beaumont, flaring
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