Clean coal technology focuses on capturing and separating carbon dioxide emissions using three main methods: pre-combustion capture which uses a shift reactor to produce hydrogen gas and carbon dioxide that can then be separated; post-combustion capture where flue gas is filtered through an amine solution to capture carbon dioxide; and oxyfuel combustion which burns coal in oxygen to produce high concentrations of carbon dioxide in the flue gases that can then be captured.

2.  Clean coal technology often concentrates on the
capture and separation of carbon dioxide emissions.
These emissions can cause significant harm to the
environment if not managed properly. Here is a brief
overview of three common methods of carbon
dioxide capture:
Pre-combustion capture —Using a shift reactor, clean
coal plants can oxidize carbon monoxide with water
to create carbon dioxide and hydrogen gas. After
separating out the carbon dioxide with
approximately 85 percent efficiency, plants can then
use the resulting hydrogen gas to generate
electricity.

3.  Post-combustion capture —Burning coal produces a
smoke-like substance known as flue gas. After coal
burns, flue gas can be filtered through an amine
solution to produce a nitrogenous compound.
Although no commercial power plants use post-combustion
capture today, several power plants in
the US have experienced significant success with the
chilled amine technology.
Oxyfuel combustion —By burning coal in oxygen
instead of regular air, clean coal plants can produce
flue gases with high concentrations of carbon
dioxide, which can be readily captured by chilled
amine technology.