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Refining Process

Simplified Diagram of Refining Process

Key Refining Unit Descriptions & Functions

The following is a summary of the primary process flow of North Atlantic's Refinery including a brief description of the process and purpose of the identified processing units. This summary excludes the various utility plants as well as a number of secondary units that add relatively small incremental enhancements to higher valued products from the diesel and fuel oil streams.

Crude & Vacuum Distillation Unit

Crude oil from tankage is heated and processed in the crude unit for primary distillation and separation into various components. The crude oil is first processed in the crude distillation tower where the crude is fractionated into the following streams:

  • Liquid and non-liquid petroleum gas products such as fuel gas, propane, and butane;
  • Light liquid products (naphtha) which are further upgraded in the naphtha hydrotreater and platformer for subsequent blending into gasoline;
  • Middle distillates (kerosene and diesel) which are produced from the middle of the distillation tower. The kerosene goes to either jet fuel blending, the distillate hydrotreater for Ultra Low Sulphur Diesel ("ULSD") production, or No. 6 fuel blending. The diesel goes to the distillate hydrotreater for ULSD production;
  • The material remaining in the bottom of the crude distillation tower ("atmospheric tower bottoms" or “ATB’s”) are sent to the vacuum tower for further separation.

The vacuum tower operates at less than atmospheric pressure and further fractionates the ATB’s. Vacuum gas-oil (“VGO”) recovered from the vacuum tower is then routed to the ISOMAX unit to be upgraded primarily into naphtha, kerosene and ultra-low sulphur diesel. The residual vacuum tower bottoms (“VTB’s”) stream is routed to the visbreaker.

ISOMAX Hydrocracker Unit

The ISOMAX unit (which is a UOP licensed hydrocracking process) uses high heat and pressure to upgrade the VGO through catalytic hydrogenation. This process removes contaminants and produces naphtha for gasoline blending and platformer feed, ULSD and jet fuel. The ISOMAX fractionation bottoms (“Frac Bottoms”) are sold as a valuable lubricant feedstock.


The VTB’s, an asphalt-like product, are further processed in the visbreaker. The visbreaker uses high temperature to crack long chain molecules thereby reducing viscosity to meet the requirements for High Sulphur Fuel Oil (”HSFO”) blending.

Naphtha Hydrotreater, Platformer, and Platformate Hydrogenation Units

The naphtha hydrotreater, uses hydrogen and a catalyst to remove sulphur and nitrogen contaminants from the naphtha to enable it to be used as platformer feed. The platformer then converts the low octane naphtha into high octane platformate for use in gasoline blending. A portion of the platformate is further processed in the platformate hydrogenation unit ("PHU"). The PHU reduces the benzene content of the platformate allowing it to be blended into Reformulated Blendstock for Oxygenate Blended (“RBOB”) gasoline.

Distillate Hydrotreater

The distillate hydrotreater operates at high pressure and uses hydrogen over a catalyst bed to remove nearly all of the sulphur and nitrogen from the middle distillates for the production of ULSD.

Storage and Shipping

Crude oil and other feedstock and finished refined products from the various processing units are temporarily stored in designated tanks. North Atlantic has storage capacity for approximately seven million barrels of crude oil and refined product. This storage capacity is allocated approximately 50% to crude oil feedstock and 50% to refined product outputs. Refined products are ultimately shipped by vessel for delivery to the United States Atlantic Coast market, including Boston and New York City, and Europe. These markets account for approximately 90% of the Refinery's production, and the balance is sold through North Atlantic’s branded and unbranded distribution and marketing network in Newfoundland. The vessels delivering refined products typically have capacities of approximately 330,000 barrels.