No timeline for restart of Texas refinery unit-Motiva

* New 325,000 bpd CDU may be shut for up to five months -sources

* CDU furnace may have been heavily damaged -experts

By Erwin Seba

HOUSTON, June 15 (Reuters) – The operator of the largest U.S. oil refinery said on Friday it did not know how long a newly commissioned giant crude distillation unit, a center piece at the Port Arthur, Texas facility, would be shut down.

Motiva Enterprises said that there was no schedule for the crude distillation unit’s return to production at the 600,000 barrel per day (bpd) Texas, refinery. Sources familiar with refinery have said the unit would be down five months for repairs.

The 325,000 bpd crude distillation unit (CDU), which was the keystone of a recently completed five-year, $10-billion expansion project more than doubling the refinery’s capacity, was shut after a restart attempt failed Saturday, the sources had said.

“The timeline for the full ramp-up of the expansion is not known at this time,” Motiva spokeswoman Emily Oberton said on Friday.

Previously, Motiva had said a unit at the refinery had been shutdown due to a mechanical issue while the expansion units were being brought to full production. When the crude unit was shut, it was within three weeks of reaching full production, according to a timeline previously laid out by Motiva.

The 285,000 bpd pre-expansion CDU continues in the production at the refinery. A crude distillation unit does the initial refining of crude oil coming into a refinery and provides feedstock for all other production units.

The lengthy shutdown is likely due to a heavily damaged furnace on the new CDU, which began production in late April, according to experts.

Oberton declined to discuss the status of individual units at the refinery when asked about the CDU’s furnace.

In a notice filed Saturday with the Texas Commission on Environmental Quality, the Motiva Port Arthur refinery said “uncontrolled combustion occurred within crude distillation unit furnace” during Saturday’s restart attempt.

“The implication is something pretty bad happened,” said David Hackett, president of Stillwater Associates of Irvine, California, an energy consulting firm. “It’s possible they could have burned the furnace up,” Hackett said.

The furnace raises the temperature of crude oil just before it enters the atmospheric section of the CDU to between 625 and 700 Fahrenheit (329-371 Celsius). In the CDU, light end products like naphtha rise as vapor in the atmospheric section while heavier products like asphalt remain liquid in the bottom of the vessel.

The light ends are removed from the atmospheric section, while some heavier products go to the vacuum section for further refining in a vacuum or to other units.

The phrase “uncontrolled combustion” could also include an explosion within the furnace, said a safety expert, who asked not be identified so he can have future dealings with Motiva or its owners Royal Dutch Shell Plc and Saudi Aramco

“Something like that can do a lot of damage,” he said.

REUTERS ARTICLE

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