By ROBIN SHANNON

L’Observateur

GARYVILLE – Marathon Petroleum Co. is seeking a state permit that would allow for an additional expansion at its Garyville refinery, according to a notice filed with the state Department of Environmental Quality.

According to the notice, Marathon wants to modify its state-issued air permit to allow the refinery to expand its hydrocracking unit’s capacity by 20,000 barrels per day (bpd) to 110,000 bpd. The company also wishes to increase a crude distillation unit’s capacity by 20,000 bpd to 290,000 bpd. Total current production at the Garyville refinery is 464,000 bpd.

Officials with Marathon declined to discuss the refinery’s plans. The project will be done in two phases, starting in November when a planned overhaul of several units will begin. The second phase is scheduled during an October 2014 turnaround at the plant.  

The crude unit scheduled for the capacity increase was added as part of a three-year, $3.9 billion expansion at the refinery that was completed in 2010. The unit has already had a 30,000 bpd increase since coming online. The expansion made the Garyville refinery the fourth largest in the nation.

A hydrocracker uses heat and catalysts to break up oil into different products such as motor fuel.

A crude distillation unit does the initial refining of crude oil coming into a refinery and provides feedstock for all other units.

Marathon also wants to optimize diesel production with work on various units at the refinery, according to the notice. There was no explicit date on the notice for the diesel project.

Documents about the proposed expansion are available at the Garyville branch of the St. John the Baptist Public Library or online at the DEQ’s electronic document management system at www.deq.gov.