The economic growth of the industrialised world is due in no small part to the use of fossil fuels, and arguably no fossil fuel has had more impact than oil. During the development of the
combustion engine the inventors quickly identified that fuels based on hydrocarbons were the most suitable, and with the growth in popularity of the
automobile a rapidly expanding industry was created almost overnight.
The rush was on, not only to locate the necessary reserves of oil, but to refine and improve the quality.
The first iterations of petrol were based on coal tar distillates and distillation of crude oil, the latter being used to power the first four-stroke cycle spark-ignition engine in 1884. At the time, petrol was considered an undesirable by-product from the manufacture of kerosene, the latter being used extensively for lighting and other commercial and domestic purposes.
As the proliferation of cars grew during the first few decades of the twentieth century, demand for petrol would see its profile as a fuel source rise, quickly surpassing the once mighty kerosene.
Thermal cracking was introduced in 1913 to convert a larger fraction of petroleum into petrol - earlier investigations had shown that the heating of crude oil caused a split-up of molecules, thus increasing the proportion of volatile fractions suitable for petrol manufacture (thermal cracking required elevated pressure for the process).
The 1920’s were a time of great innovation in the automotive world, and oil companies needed to invest heavily in refining techniques to ensure their petrol would meet the ever more exacting standards being required to run the latest engines.
During that time it was found that certain silica/alumina-based catalysts accelerated the reaction rate to the extent that high pressure became unnecessary. The advantages of catalytic cracking over thermal cracking were a higher petrol yield and a better quality of product. Then, in 1926, lead was used as an anti-knock agent.
Next came a breakthrough in the catalytic cracking process, the initially developed fixed-bed catalytic process was replaced by a fluid-bed process, which allowed for excellent control of temperature and reaction, in the process providing better yields of petrol from the refineries.
The introduction of the catalytic cracking process and catalytic reforming in the 1940’s was significant for the manufacture of high-octane petrol components. During the 1950’s
automobile manufacturers started to increase the compression ratios in their engines, resulting in higher octane ratings, lead levels, and vapour pressure.
Minor improvements continued to be made to petrol formulations to improve yields and octane, including the introduction of so-called performance additives such as “Platformate” and “Activate”.
From the 1970s petrol underwent a slow evolution, most evident to the classic car enthusiast being the phasing out of leaded petrol (unleaded fuels were introduced to protect the
exhaust catalysts that were being introduced for environmental reasons).
The government set a deadline for all service stations throughout Australia to provide unleaded fuel by 1986, and in the process we stopped calling our petrol simply “Super”, instead having to refer to is as either “Unleaded” or “Leaded”, although for a time through the 1990’s it was a little confusing, with iterations such as “Half Lead” and “Lead Free”.
