By Erwin Seba
HOUSTON (Reuters) - Motiva Enterprises began restarting partial production at the nation's largest crude oil refinery on Tuesday, the company said.
Motiva was ready by Tuesday morning to restart the large crude distillation unit, hydrocracker and coker at the 603,000- barrel-per-day Port Arthur, Texas, refinery shut on Aug. 30 by Tropical Storm Harvey, several sources familiar with Motiva's plans said.
"We expect the refinery to initially return to approximately 40 percent production by the end of this weekend, provided that the final assessments meet our operational standards," Motiva spokeswoman Angela Goodwin said in a statement.
The company had been waiting on the restoration of shipping and pipelines to begin the partial restart, the sources said.
The time line for restarting the other units in the refinery had not been determined as charge pumps, compressors and other ground-level equipment that moves oil and other liquid hydrocarbons into production units have been underwater since heavy rains inundated the plant on Aug. 29, the source said.
A layer of oil spread over the water from a ruptured tank, the sources said.
Checking and repairing the pumps and compressors could take a month to complete, the sources said.
The area encompassing the 325,000-bpd VPS-5 crude distillation unit (CDU), 105,000-bpd hydrocracker and 110,000- bpd coker was relatively dry, enabling a quicker restart for those units, the sources said.
Those units were part of a $10 billion expansion completed in 2012 that more than doubled the refinery's crude oil processing capacity.
Water levels in other portions of the refinery were between 3 and 4 feet (0.9 and 1.2 m) deep, the sources said.
The refinery's production units, like the CDU, hydrocracker and coker, were most likely protected by being elevated and sealed as part of their design, according to the sources.
CDUs do the initial refining of crude oil coming into a refinery and provide feedstock for all other units.
Hydrocrackers produce motor fuels, primarily diesel, by processing gas oil under high heat and pressure in the presence of hydrogen and a catalyst.
A coker converts residual crude oil into feedstock for producing motor fuels or petroleum coke, a coal substitute.
Saudi Aramco [IPO-ARMO.SE] took sole ownership of Motiva on May 1 after completing the planned breakup with Royal Dutch Shell Plc (L:RDSa) of a joint venture that operated the company for nearly 20 years.