Oxy-fuel combustion process

Since the nitrogen component of air is not heated, fuel consumption is reduced, and higher flame temperatures are possible.

[2] There is currently research being done in firing fossil fuel power plants with an oxygen-enriched gas mix instead of air.

[3] Firing with pure oxygen would result in too high a flame temperature, so the mixture is diluted by mixing with recycled flue gas, or staged combustion.

However, oxy-fuel is a viable alternative to removing CO2 from the flue gas from a conventional air-fired fossil fuel plant.

The glass industry has been converting to oxy-fuel since the early 1990s because glass furnaces require a temperature of approximately 1500 degrees C, which is not economically attainable at adiabatic flame temperatures for air-fuel combustion unless heat is regenerated between the flue stream and the incoming air stream.

The planned project was an oxy-fuel power plant coupled with air separation to capture two million tons of carbon dioxide per year.

Because oxyfuel combustion results in flue gas that already has a high concentration of CO2, it makes it easier to purify and store the CO2 rather than releasing it to the atmosphere.

Free lime forms when carbonate minerals in fuels like coal and oil shale decompose at the high temperatures occurring during combustion (calcination).

Because oxyfuel combustion takes place in a CO2-rich atmosphere, decomposition is reduced and the ash generally contains less free lime.