Most of our energy requirements come from burning of fossil fuels like oil, natural gas and especially coal, which leads to high CO2
emissions in the atmosphere. Carbon Capture is the process by which carbon dioxide is first separated from the flue gases of power-plants and other industries and then reused in other industrial processes or stored deep underground, thus preventing it from being released in the air. Carbon Capture can reduce the CO2
emissions from these plants by almost 90%.
The International Energy Agency (IEA) has studied a number of global greenhouse-gas-reduction scenarios and concluded that CCS is "the most important single new technology for CO2
savings" in both power generation and industry. The agency estimates that attempting to stabilize emissions without CCS could cost about 70% more—equivalent to $4.7 trillion between 2010 and 2050. CO2
can be captured either before or after burning of the fossil fuels through various techniques such as Post-combustion Carbon Capture, Pre-combustion Carbon Capture and Oxy fuel combustion.
Post Combustion Capture
This is the most technologically proven and widely tested method of carbon capture which uses chemical/physical solvent to isolate and capture CO2
after combustion of fossil fuels. This method is most suitable for pulverized coal, supercritical and ultra super critical power plants.
Pre combustion Capture:
In this method, carbon dioxide is removed from the fuel before it is burnt. The syngas is further shifted through water to produce CO2
and H2 which is stored and used separately. This method is mostly applicable in IGCC (integrated gas combustion cycle) power plants, chemical and fertilizer industries.
Oxy Fuel Combustion:
This process uses a conventional boiler where the fossil fuel is burnt in pure oxygen and re-circulated flue gases. The result is a pure stream of concentrated CO2
. Though this method can reduce carbon emission to almost nil, it's a highly energy intensive process.