Shell's Norco, Louisiana, gasoline unit restart delayed 1-2 weeks -sources

(Adds details about other units, background)

HOUSTON, April 24 (Reuters) - The restart of the gasoline-producing unit at Royal Dutch Shell Plc's 218,200 barrel-per-day (bpd) Norco, Louisiana, refinery has been delayed between one and two weeks, said sources familiar with plant operations on Wednesday.

The restart of the 112,000-bpd gasoline-producing Residual Catalytic Cracking Unit from a two-month overhaul was scheduled for May 8, but is now expected to take place in the third or fourth week of May, the sources said.

Shell is preparing to restart the 14,800-bpd alkylation unit, which is expected to resume operations as early as this week, according to the sources. Also, an overhaul of the Sulfur Recovery Unit 3 (SU-3) is finishing up and the unit is expected to restart soon.

The RCCU uses a catalyst under high heat and pressure to convert residual crude oil into gasoline. The more common fluidic catalytic cracking unit processes gas oil.

The alkylation unit converts refining byproducts into octane-boosting components blended into gasoline.

Sulfur recovery units extract sulfur from hydrogen sulfide removed from motor fuels in compliance with U.S. environmental rules. (Reporting by Erwin Seba; Editing by Peter Cooney)