Oil has 40 years left, what’s next for the petrochemical industry?
Crude oil is the most versatile and useful fossil fuel. Like coal and natural gas it has formed in the Earth’s crust over millions of years from the fossilized remains of algae, plankton, corals and other sea life.
Over time the high pressure and temperature in the Earth’s crust has compressed these fossils into crude oil. Crude oil is composed mostly of hydrocarbons, molecules that contain just C and H atoms, and a small number of inorganic compounds such as H2S. The crude oil is separated using fractional distillation. Different hydrocarbons boil at different temperatures, which means we can collect groups, or fractions, that boil at the same temperature. Some of these smaller chain fractions are very useful, for example petrol and kerosene are used as fuels for cars and airplanes respectively, and many fractions are used to produce petrochemicals. Less useful fractions can be cracked, broken up into smaller useful compounds, or reformed (re- arranged) to increase their use and meet the demand of more useful fractions. Crude oil is an invaluable resource. The oil industry was estimated to be worth $3.3 trillion in 2019, but it is a finite resource. There are approximately 1,500,000,000,000 barrels of oil left in the world and we use around 35,000,000,000 barrels per year, meaning we have only 40 years of oil left! This poses the question, what’s next?
Another crucial fossil fuel is natural gas. Like crude oil it has formed over millions of years from compressed plant and animal matter. Natural gas is mainly the simplest hydrocarbon methane, but it also contains larger hydrocarbons, that often liquefy to form natural gas liquids, and a small number of inorganic compounds such as helium and H2S. The natural gas liquids can be used in a similar way to some fractions of crude oil, such as petrochemical production and vehicle fuel. Natural gas is still used to produce electricity, whereas crude oil is no longer used due to its limited availability and importance in petrochemical production. Natural gas can be converted into hydrogen and carbon monoxide, a specific combination of gases called synthesis gas, which is a useful intermediate for many chemicals. Syngas (synthesis gas) can be converted into organic liquids that are like fractions of crude oil. This can be done by the Fischer-Tropsch process, which is not fully understood even 65 years after its invention. Despite this the process has been developed over the last 65 years and it is now widely used to convert natural gas to liquids, so it provides a viable alternative to oil, however industry infrastructure will need to be completely overhauled to make it economically efficient. Additionally, natural gas is a fossil fuel and it’s expected to run out in just 90 years.
Coal is the third and final fossil fuel, it is in the most plentiful supply (150-440 years) and most evenly spread geographically leading to fewer political issues. However, coal is the most environmentally damaging. Coal extraction causes extensive land damage and water pollution and the burning of coal to generate electricity or syngas produces PAH’s (polycyclic aromatic hydrocarbons) and particulates, which are carcinogenic and cause heart and respiratory diseases. Although coal can be burnt to produce syngas and thus organic liquids, the process would be very energy intensive, costly and damaging to the environment. It is currently unlikely that coal provides a viable alternative to oil.
Biomass provides our first renewable alternative. Mainly composed of plant matter and animal fats, biomass can be burnt to produce energy and syngas, which can be converted to liquids by the Fischer-Tropsch process. However, biomass gasification currently requires high temperatures and has low yields. There is ongoing research into new mechanisms for the conversion of biomass to liquids. Biomass farming requires a large amount of land, leading to conflict. It’s very labour intensive and the technology is currently underdeveloped.
The future of the petrochemical industry is uncertain, natural gas provides a short-term solution, but a sustainable long-term result is yet to be found. It will be the role of aspiring chemical engineers, such as myself, to find a sustainable solution to one of our greatest problems.
Written by Ben Conroy, studying Chemical Engineering at the University of Surrey. Ben is a founding member of the Alumni Association and actively works to support fellow alumni students and develop the reach of the Association for the benefit of his World Class peers. Ben was formerly a student at World Class Ivybridge Community College in Devon.