Mandan Refinery Successfully Expands
Distillate Desulfurization Unit
In 2012, Tesoro’s refinery in Mandan, N.D. had just completed a successful expansion of its crude unit, allowing approximately 10,000 more barrels of crude from the Bakken oil fields to be processed every day. The refinery team then turned to its next planned improvement: the expansion of the refinery’s distillate desulfurization unit (DDU). This was a real opportunity for Tesoro to benefit from the high demand for diesel fuel in North Dakota. Owing partly to the booming Bakken activity, the state has been hard pressed to keep up with this demand.
“Most diesel has been brought in from outside the state, and diesel pricing is higher than for gasoline,” said Todd Dixon, Mandan Refinery Manager. “It seemed like a good opportunity for Tesoro to benefit from diesel demand in the market.”
With such a strong business case in place, the refinery team moved ahead to develop a plan for the DDU expansion. In order to achieve the planned increase in diesel output, the team needed to make a number of engineering modifications to major process equipment. Also required were upgrades to piping systems, electrical infrastructure and instrumentation.
While the project was less complex than the completed crude unit expansion, it demanded superior execution from the team.
“It’s challenging to run a refinery while also managing a fast-track expansion project,” Todd said. “Our team was responsible for both. Fortunately, we were able to get our refinery craft personnel engaged at the right time.”
Specific improvements to the DDU included:
- Revamp of the existing charge pumps, which would increase motor horsepower from 450 horsepower to 600 horsepower.
- Replacement of the existing feed/effluent exchangers with new, larger, state-of-the-art equipment.
- A new reactor charge heater.
- Modification to the existing reactor, stripper tower and pumps.
“The most ambitious part of the project was constructing a new pressure swing adsorption (PSA) unit,” Todd said. “This PSA unit delivers high-quality hydrogen to the DDU, which facilitates our running at a higher rate.”
The expansion is an excellent example of Tesoro’s strategy to invest capital in high-return, short-payback projects. With the DDU expansion completed in the second quarter of 2013, the refinery is now capable of producing a total of 22,000 barrels per day of diesel, as it was designed to do. Meanwhile, financial returns have also been consistent with the original plan.
Finally, as Todd points out, all of this was accomplished with the proper attention to safety: Not a single refinery worker was injured during the entire project.
“We were able to keep appropriate perspective, particularly on safety,” Todd said. “We didn’t let our sense of urgency get in the way of the most important thing: our people getting the project done and not getting hurt while they’re doing it.”
Find this story and learn more about Tesoro’s Guiding Principles in our 2013 Social Responsibility Report.