Refiners in the U.S. are enjoying a feedstock price advantage relative to most of the world. However, with this opportunity comes challenges and some confusion with preparing for the crude quality shifts resulting in the “dumb-belling” of U.S. crude supplies, such that the lights get lighter and the heavies get heavier—ultimately resulting in declining middle-distillate yields.

John Auers, executive vice president of Turner, Mason & Co., told Hart Energy recently, “Production of diesel, fuel oil and jet fuel will fall, cutting off much of the lucrative diesel export market.”

But solutions do exist.

The incredible rise of North American crude production from the shale plays and heavy Canadian crude has pumped massive volumes of crude with qualities not particularly suited for many refineries.The blending of North American crudes from the heavy western Canadian crudes in the north to the ultralight sweets in the Midcontinent and south has resulted in a cocktail blended from both ends of the gravity spectrum.

Crudes have always been blended to meet specific criteria for individual refineries, depending on the units as well as the time of year and whether the product yield is more weighted to petrochemical feedstocks or to fuels like distillates. However, the growth in production from shale and tight oil plays has been so fast that infrastructure is still playing catch-up.

William Poe, senior principal technical consultant with Schneider Electric (Invensys), told Hart Energy, “There are ways to deal with this problem with model-based solutions. The blended crude components and cuts can be more accurately characterized with assay analytical tools and advanced process control can be used to fully utilize the light ends and heavy ends processing capability of the refinery.”

Turner, Mason’s Auers also cautioned, “As many refineries shift to a lighter crude slate, they could see a 10% reduction in capacity.” It therefore stands to reason that a significant percentage of infrastructure investment includes hardware upgrades to recover that 10% reduction. Meanwhile, individual refining facilities eagerly await the debut of a crude cocktail formulation palatable to a majority of plants. For example, PBF’s Delaware City, Del., refinery came up with a customized formulation with the flexibility needed to blend more artificial crude blends, creating a de facto blend that is being dubbed “Philly Light.”

Auers added, “Each facility develops its own unique strategies.”

In the case of the Canadian crude imports to the U.S., which could reach 3 MMbbl/d by 2020, this heavy feedstock flows to the refinery as dilbit, a combination of very heavy bitumen crude and diluents. The diluents are usually a very light naphtha, natural gas or condensate from wet shale gas.

BASF’s Technology specialist Melissa Clough and technical marketing specialist Alexis Shackleford told Hart Energy, “There are many differences a refiner must be aware of when processing Canadian crude blends [such as dilbit or synbit]. Upon blending of light tight oil, or shale crudes, with heavy Canadian crudes, incompatibility can induce asphaltene precipitation, which negatively impacts the refining process.”

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