Petrochemical Engineering in Canada:

The Process  

What could be more appropriate than to have Petro-Canada help us learn about the world of chemical engineering and petrochemistry in Canada? Petro-Canada is, in fact, Canada’s largest petrochemical company. With refineries in Edmonton, Oakville and Montreal, its plants transform crude petroleum into gasoline and a number of other quality products. The Oakville plant alone employs over two hundred workers, including many chemical engineers and technicians who are mainly responsible for the quality and smooth performance of the processes. The chemists employed in Oakville primarily conduct laboratory research to ensure constant improvement in the quality of the products and process efficiency. The following paragraphs explain the petroleum refining process and the chemical principles that are applied during operations. 

The 13,000 cubic metres (89,000 barrels) of crude petroleum refined each day in Oakville must undergo a very precise purification sequence. Crude petroleum is a complex mixture of several organic molecules called hydrocarbons. Refining is the process through which these various compounds are separated, some of them are converted, and impurities are eliminated. The first step is "separation".  Imagine an enormous kettle in which the various crude petroleum compounds are evaporated one after another at different boiling points. This is a chemical process known as distillation. The virtually pure vapours recovered in tall columns are then cooled at specific temperatures, condensed, and extracted separately. The viscous, non-volatile residue remaining at the bottom will be used in the manufacture of asphalt or used as heavy heating oils or lubricants.   

The second major step is "conversion." This step consists of changing the chemical structure of the extracted petroleum fractions to obtain superior quality products such as gasoline. Conversion first includes the “reforming procedure”, which will change the shape of the molecules, followed by the cracking process, which will break the large molecules into smaller, more similar molecules. Conversion ends with alkylation, which combines the small molecules into the desired identical, larger molecules such as octane in gasoline. The series of steps is carried out at very high temperatures, using a catalyst, and the entire process is supervised by chemical engineers.  

The third step is "treatment of impurities." Physical and chemical separations such as precipitation and dissolution are performed to remove impurities such as sulphur from the environment. The gas phase sulphur thus collected is sent to specialized treatment plants where it is converted into liquid sulphur and stored. If this purification step were omitted, the impurities would cause corrosion and damage the operation of vehicles.  

Finally, the term "blending" characterizes the last step in which all the final adjustments and specificities are carried out. Particular products are added depending on the season, and each sample is checked to ensure that it contains the desired specific mixture. 

Although gasoline is the main product of crude petroleum, a number of other by-products are also obtained. These include diesel oil and kerosene (aviation fuel discovered by the Canadian, Abraham Gesner, in 1853), heating oil and lubricants. By-products obtained from the refining process are also used in the manufacture of plastics, synthetic fibres, synthetic rubber and a number of other products for daily use.