Northern Tier shutters unit for unplanned maintenance at Minnesota refinery

Northern Tier Energy LP has shut down a crude unit for unplanned maintenance at its 97,800-b/sd refinery in St. Paul Park, Minn.

Unplanned maintenance at the refinery’s 58,000-b/sd No. 2 crude unit was due to begin as of Sept. 17, Northern Tier said.

As a result of the unscheduled shutdown, overall refinery crude throughput during this year’s third quarter likely will average between 86,000-90,000 b/sd, the company said.

A reason for the unplanned maintenance event was not disclosed.

Northern Tier previously intended to take the No. 2 crude unit down for regularly scheduled maintenance during a planned turnaround in second-quarter 2016, David Lamp, Northern Tier’s president and chief executive officer, said in an Aug. 4 quarterly earnings call.

During that scheduled maintenance period, the company also planned to execute modifications to the No. 2 crude unit and associated ultralow-sulfur diesel hydrotreater in order to boost crude throughput capacity and distillate yields, Lamp said.

Once completed, the revamp projects would raise crude throughputs by up to 4,000 b/sd and diesel recovery by 2%, Northern Tier said in a September presentation.

Designed to increase crude-input flexibility, a separate project also is under way to replace existing single-stage desalters with two-stage desalters at each of the refinery’s two crude units.

In addition to improving process reliability by reducing salt-related corrosion, the desalter replacements would equip the plant with a greater flexibility to increase recovery of diesel vs. gasoline, the company said.

As of Sept. 9, Northern Tier planned to complete installation of the desalter at the refinery’s 39,800-b/sd No. 1 crude unit by yearend 2015, with No. 2 crude unit’s desalter scheduled to wrap installation by midyear 2016.

The company said it continues to develop other projects to improve operations at St. Paul Park, including installation of a solvent deasphalting unit to fill available capacity in the refinery’s fluid catalytic cracking unit, as well as a revamp of plant’s No. 1 crude unit that would lift its processing capacity.

Contact Robert Brelsford at [email protected].