Regardless of the type of crude we start with, it needs to be refined, or "distilled". Distillation is what happens at the refinery. Crude oil is made up of hydrocarbons - molecules that contain a lot of energy (chemically speaking) and can be used to make different petroleum products like gasoline, diesel, kerosene, jet fuel, and asphalt. During distillation, we heat and separate the different molecules in order to further process them into their end product.

This image (courtesy of the BBC) shows the vaporization temperatures of the different hydrocarbon molecules used in various products. After separation, we now have different streams or fractions.

Following separation, we convert the fractions. Conversion, also called “cracking”, lets us manipulate the molecules to get the desired amounts of the different products. Since lighter petroleum products like gasoline are typically higher in demand than heavier products, we convert to get more of the products our customers want.

Finally, these fractions go through a final treating process to remove any excess water, sulphurs, stray compounds and/or residual solids. Then to make sure our petroleum products meet government standards as well as customer requirements, we blend fractions to create different products. For example, gasoline is blended differently in the summer and the winter. In the winter, we create a "lighter" fuel that minimizes potential problems due to condensation in fuel lines; our winter blend also evaporates more readily for improved cold-weather startups - remember, cars burn vapour not liquid, so when temperatures are colder, the gasoline needs a little help to evaporate.

Once the gasoline is blended to specification, we need to get it from the refinery to a terminal. Fuel can travel by pipeline, ship or rail to get to the terminal. At the terminal, we make one final adjustment to the fuel. First, we put in additives to the gasoline. Our proprietary additive, Tactrol, acts as a detergent to prevent deposit build-up. The terminal is also where we add ethanol; ethanol is used as an octane booster and is what makes our high-performance fuel, Ultra 94.

If you're keen to learn more about our use of ethanol as well as things like an Anti-Knock Index and the nuances of octane numbers, you can check out our Gasoline FAQs. 

A tanker truck leaving the fuel rack at Suncor's Commerce City refinery

But back to the terminals. This is the last step to get the fuel to the pump. At the terminals, fuel trucks load up and transport the fuel to the gas station. At the station, the fuel is stored underground in double-walled tanks. Different blends of gasoline (e.g. Ultra 94 or SuperClean) are stored in separate tanks. Then, when you visit one of our stations, the pump pulls the fuel from the tanks, depending on the type of gas that you purchase.

Now, a question we often hear from our Ultra 94 users is about the "hold up" in the delivery hose, i.e. if the customer before you has purchased regular gasoline (87 Octane) and you purchase Ultra 94, won't you get a lower octane blend? Thankfully, the answer is no.

We use a blender-style pump that is approved by Measurement Canada and it does leave a small amount of fuel from a previous fill in the delivery hose. Based on our calculations for an average 50L fill, this could result in a reduction of octane content of approximately 0.16 octane units, if the previous customer purchased Regular (87 Octane), and the one to follow Ultra 94. The typical octane level in Ultra 94 is 94.2. So, we are confident that even with the small degree of product mixing that may occur in an approved blender-style pump, the Ultra 94 that you're purchasing meets our standards and your expectations.

The fuel gets to you at the Petro-Canada retail station

And that is how crude oil becomes gasoline and gets to the pump at the station.

More questions about how crude becomes gasoline? Leave them in the comments!

- Rose R.