Obtaining and Using Hydrocarbons


This is part of the HSC Chemistry course under the topic Hydrocarbons.

HSC Chemistry Syllabus

  • examine the environmental, economic and sociocultural implications of obtaining and using hydrocarbons from the Earth


How are Hydrocarbons obtained from Earth?

  • Hydrocarbons, mainly alkanes, are extracted from crude oil/petroleum which forms in oil reservoirs within the lithosphere of Earth. 


Detecting Hydrocarbons

  • Geologists use seismic surveys to search for geological structures that may form oil reservoirs.
  • One common method involves making an underground explosion nearby and observing the seismic response that provides information about the geological structures under the ground.


Extracting Hydrocarbons

  • Extracting crude oil normally starts with drilling wells into an underground reservoir. 

Separating Hydrocarbons

  • The crude oil then undergoes fractional distillation, to separate the various components of the mixture into their useful fractions, based on boiling point and chain length.
  • Larger hydrocarbons (higher boiling point) are condensed into liquid state first while those with lower boiling points will rise upwards in the distillation chamber until they reach their boiling point 


Implications of Obtaining and Using Hydrocarbons From the Earth

Sociocultural Implications

  • During the twentieth century, the world population increased significantly. With this increase in population came increased demands for materials such as fuels for transport, industry and heating, materials for construction to replace and supplement timber and iron, fibres for clothing and household goods and chemicals to improve medical care. For a large part of that century, the demands were satisfied by hydrocarbons in fossil fuels. 
  • As the demands for liquid fuels for transport increased, crude oil refining increased, and crude oil provided not only petrol, diesel and aviation fuel but also chemicals such as ethylene, which is an essential raw material for polymer production.
  • Chemical industries based around fossil fuels developed. These included manufactures of polymers, such as polyethylene, PVC and polystyrene, as well as synthetically produced materials including esters, acids, alcohols, nylon, polyesters, synthetic rubber. These chemicals, based on the petroleum industry, changed the lifestyles of society.


Economic Implications

  • Significant economic growth for countries that have access to oil reservoirs as crude oil forms a major party of their export.
  • The exponential use of petroleum led to dwindling supplies and high costs of this non-renewable fossil fuel and by the late 1900s it became evident that traditional materials needed to be supplemented or replaced by others derived from renewable resources.
  • Electrical energy, once largely provided by the burning of fossil fuels such as coal in power stations, is now supplemented by the use of batteries and the development of the renewable energy industry. Renewable energy production is not only environmentally but also more economically viable in the long-term.


Environmental Implications

  • Extraction of crude oil from oil reservoirs creates large cavities underground which may cause overlying geological structures to collapse 
  • Oil spills impose significant damage to the environment especially aquatic ecosystems. Oils spills are also difficult to clean up.
  • Issues associated with climate change, related to the use of carbon-based fuels, need resolution in the short-term, as will the decreasing supplies of the non-renewable resources upon which chemical industry is still dependent. The use of renewable solar, wind, wave and geothermal power sources will become more significant, with the possibility of nuclear energy being harnessed safely for future generations.
  • Materials produced by the chemical industry using components of crude oil as the raw materials are non-biodegradable. Therefore, their disposal poses an environmental concern, particularly in the long-term as the amount of non-biodegradable materials being used accumulate