Supercritical carbon dioxide

Supercritical carbon dioxide

Subject : Environment

Section: Climate change

Concept :

• A new research by IIT Madras has suggested the use of Supercritical carbon dioxide to flush out oil from depleting oil and gas reservoirs.

About Supercritical carbon dioxide:-

• Supercritical carbon dioxide (CO2) is a fluid state of CO2 where it is heated and held at or above its critical temperature(31∘C) and pressure(73 atm).
• In this supercritical phase, CO2 exhibits properties and behaviours between that of a liquid and a gas.
• Supercritical CO2 possesses liquid-like densities with gas-like diffusivity, surface tension and viscosity.

‘Surfactant-Alternating gas (SAG) injection’ approach:

• In this process, carbon dioxide gas is injected into the reservoir, where it becomes supercritical, followed by injection of water or surfactant solution.

Use of Supercritical Carbon Dioxide (CO2):-

• It is used in the oil and gas industry for gas injections during enhanced oil recovery (EOR) techniques.
• When supercritical CO2 reacts with water, carbonic acid (H2CO3) is formed.
• Carbonic acid lowers the pH in the reserve and creates an environment that is corrosive to metal equipment.