Petroleum Refining

Petroleum refining can be defined as the physical, thermal and chemical separation of crude oil into major distillation components, or fractions. These distillation fractions can be further processed through separation and conversion into finished petroleum products. A petroleum refinery is the facility where this process takes place. Petroleum refinery facilities distil or separate crude oil into smaller fractions (or groups of molecules) in order to make more than 2500 different products that we use in our vehicles, homes, and industries.

These products can be broadly grouped into three main areas:

  • fuels (such as motor gasoline, diesel fuel, aviation fuel, light and heavy fuel oil),
  • non-fuel products (such as lubricating oils and greases, asphalt) and
  • raw materials for the chemical industry.

Refinement Process

The refinement of fossil fuels involves a number of steps including: distillation and separation; conversion or upgrading, desulphurization or sweetening; and in some cases the use of additives to improve the fuel's performance.

Distillation, separation, conversion and desulphurization techniques are influenced by the different chemical and physical properties of each fraction or part of crude oil. Often high levels of heat and pressure, along with catalysts, are used to break down the crude oil into its component parts, or to clean it of impurities such as sulphur. “Cracking” and “coking” are two techniques used by refineries to perform this task.

Different petroleum refineries use different refining techniques and technologies.

Petroleum Refining in Canada

Oil was first discovered in the early 1700s as a bituminous gum that flowed out of the banks of the Athabasca River, in Alberta.

It wasn't until the mid 19th century before the first oil refinery, using a fractional distillation process, could change oil into more refined products such as kerosene.

Around 1870, nearly 20 small refineries existed in southern Ontario, mainly to produce kerosene. At that time, gasoline, naphtha and benzene were regarded as by-products and were discarded!

At the beginning of the 20th century, automobiles powered by gasoline gained popularity, providing a market for this previous by-product, gasoline.

In 1947, the giant Leduc was discovered near Edmonton, which was the largest oil field of its time. Leduc produced oil continuously until the 1990s. It made Western Canada the centre of the Canadian oil industry and encouraged an exploration surge!

Canadian petroleum refineries obtain crude from numerous sources including oils fields and oil sands operated by the upstream oil and gas industry, as well as imports from other countries. They are also responsible for the distribution of refined petroleum to users and for further processing to domestic and international destinations.

Air Emissions from Petroleum Refineries

The petroleum refining process results in the release of a number of air pollutants, including: sulphur oxides, nitrogen oxides, volatile organic compounds, particulate matter, carbon monoxide, and benzene, as well as many greenhouse gases (GHGs).

Based on emission information provided by the petroleum refining sector, the refining industry's contribution to overall emissions is summarized in the table below:

Refinery Emission Summary
 % of total industrial source emissions, 2005Footnote a
Sulphur Dioxide6.9%
Nitrogen Oxides3.9%
Volatile Organic Compounds2.1%
Total Particulate Matter1.3%
Carbon Monoxide1.3%
BenzeneFootnote b18.7%


Footnote A

These percentages are based on the national emission inventory for 2000.

Return to footnote a referrer

Footnote B

For benzene, data is for 1999/2000, from Benzene Canada-wide Standard Phase 1 - National Summary, Annual Progress Report, December 2001.

Return to footnote b referrer

Under the auspices of the Canadian Council of Ministers of the Environment, Environment Canada was engaged in the development of the National Framework for Petroleum Refinery Emissions Reduction. The Framework was coordinated by a multi-stakeholder Steering Committee co-chaired by Alberta Environment and Environment Canada and included representation from federal, provincial, municipal, governments, the Canadian Petroleum Products Institute and non-governmental health and environmental organizations. The Refinery Framework's goals are to help protect human health and the environment and help achieve substantive emission reductions-as high as 50% of some parameters at some facilities. The Framework also aims to achieve convergence of the environmental performance of Canadian refineries with comparable refineries in the United States.