(Adds details about refinery, owners)
HOUSTON, Feb 18 (Reuters) - Motiva Enterprises has delayed the restart of the second-largest crude distillationunit at the company's 603,000 barrel per day (bpd) Port Arthur,Texas, refinery to next week, sources familiar with plantoperations said on Thursday.
A 49,000 bpd catalytic reformer, which was also shut as partof a planned seven-week multi-unit overhaul, has returned tooperating temperature and is circulating feedstock, but will notresume production until the restart of 195,000 bpd CDU calledVPS-4, which is expected by Monday, the sources said.
A company spokesman said on Thursday that plannedmaintenance was still underway at the refinery, but declined todiscuss the status of individual units.
VPS-4 was originally scheduled to restart on Thursday, afterthe reformer, which was expected to restart by Feb. 13. That waschanged last week by a plan to restart the CDU followed byreformer.
One cause of the delays and changing restart schedules aredifficulties installing new instrumentation on the two units,according to the sources.
Motiva is a 50-50 joint-venture between Royal Dutch ShellPlc and Saudi Aramco. The company's PortArthur refinery is the nation's largest. (Reporting by Erwin Seba; Editing by Marguerita Choy and AlanCrosby)