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By Erwin Seba
HOUSTON, Sept 30 (Reuters) - Motiva Enterprises {MOTIV.UL]began shutting down the hydrocracking unit (HCU) at the603,000-barrel-per-day Port Arthur, Texas, refinery on Fridayfor a planned two-month overhaul, said sources familiar withplant operations.
The $250 million hydrocracker overhaul will prepare therefinery, already the largest in the United States, for eventualexpansion as the centerpiece of Motiva's plans to grow arefining network along the Gulf Coast under the sole ownershipof Saudi Aramco
Motiva spokeswoman Angela Goodwin declined on Friday todiscuss operations at the refinery and possible expansion plans.
"Due to competitive reasons, it is our policy not to provideoperational status on individual units," Goodwin said.
The overhaul of the 60,000-bpd HCU will enable the unit toexpand more than three times its current throughput as therefinery improves efficiency, according to the sources
"The hydrocracker turnaround is a massive project," one ofthe sources said.
Motiva expects to increase the capacity of the refinery'slargest crude distillation unit, the 325,000-bpd VPS-5, to400,000 bpd, possibly as early as the end of the decade, thesources said.
VPS-5 feeds the hydrocracker and was built along with theHCU in a massive expansion completed in 2012 that more thandoubled the refinery's capacity.
The increase to 400,000 bpd would coming through improvingVPS-5's efficiency, the sources said.
Motiva is co-owned by Saudi Aramco and Royal Dutch Shell Plc, but the partners have agreed to divide up the refiningand marketing joint venture by April 1, 2017. Saudi Aramco isscheduled to take ownership of the Motiva name and the PortArthur refinery along with distribution assets.
Saudi Aramco and Motiva are weighing an expansion of thePort Arthur refinery to 1 million bpd, but no time frame hasbeen set, and would likely require another crude distillationunit, the sources said.
Saudi Aramco was the leading bidder for LyondellBasellIndustries 263,776-bpd Houston refinery, intended foraddition to the post-split Motiva.
The hydrocracker, which uses hydrogen under high pressure toproduce motor fuels, especially diesel, will be shut down byearly next week, the sources said.
Crude distillation units do the initial refining of crudeoil coming into a refinery and provide feedstock for all otherunits. (Editing by W Simon and JS Benkoe)