process plant

Long term storage of carbon dioxide

Carbon dioxide is produced when fossil fuels are burnt. Most combustion is in air, in which case nitrogen will be present. Coal produces CO2 and nitrogen, and hydrocarbons produce CO2, steam and nitrogen. The gases are subject to a multistage process before the carbon dioxide can be stored.

  • Separation, typically using amine solvents.
  • Compression.
  • Drying.
  • Liquefying.
  • Pumping.

These consume a considerable amount of energy.

Bulk storage will be in underground reservoirs, for example where oil has been extracted. Site selection is critical, to prevent the gas from escaping. Ideally, the CO2 should react with the containing rocks, and be buried deep down, and below multiple impervious layers. Many potential sites have been identified, but they are not necessarily close to where they are needed.

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Reusing carbon dioxide

An example is Omnagen’s innovative self-powered CO2 converter; a device which converts carbon dioxide, methane and air into useful chemicals, without the need for external energy. This is how the device works.

Carbon dioxide is a very stable molecule, it will react with some minerals to form stable carbonates, but other reactions require energy. Photosynthesis, for example, uses energy from the sun to convert CO2 and water into glucose and oxygen.