Oxy-Fuel Combustion

Oxy-fuel combustion burns a fuel in pure oxygen, or in a mixture of oxygen and recirculated flue gas, instead of ordinary air, which removes nitrogen from the combustion process entirely; historically the approach higher flame temperatures made it useful for welding and metal cutting long before its current interest as an emissions technology. Because pure oxygen alone would produce dangerously high flame temperatures, plants dilute it with recycled flue gas or use staged combustion, and the resulting exhaust gas volume runs about 75 percent smaller than conventional air fired combustion, made up mostly of carbon dioxide and water vapor. That concentrated carbon dioxide stream is far easier to capture and store than the diluted exhaust of ordinary combustion, which is why oxy-fuel combustion has drawn considerable attention in recent decades as a potential carbon capture and storage technology, and several pilot plants worldwide are now testing whether it can be retrofitted onto existing fossil fuel power plants and industrial processes at scale.