Oxy-Fuel Combustion Capture:
During oxy-fuel combustion the fuel is combusted in the presence of nearly pure (approximately 98%) oxygen (O2) to ensure that the products of combustion, collectively called flue gas, contain carbon dioxide (CO2) and water (H2O) with only trace amounts of other gases (see equation C) (Simbeck & Roekpooritat, 2009). The CO2 can more easily be removed from this flue gas than from flue gas produced in conventional combustion, a process in which CO2 is typically combusted in air made up of roughly 79.9% N2, which dilutes the CO2 concentration in the flue gas (see equation D) (MIT, 2009).
equation C) CxHy(s) + (x + y/4)O2(g) → xCO2(g) + (y/2)H2O(g), where x and y are variables
equation D) CxHy(s) + (x + y/4 + 1)O2(g) + N2(g) → xCO2(g) + (y/2)H2O(g) + 2NO, where x and y are variables
The average oxy-fuel combustion plant captures approximately 92.6% of CO2 emissions (Simbeck, 2009a).
- The gas produced is ready for geological sequestration (Simbeck & Roekpooritat, 2009).
- The total mass and volume of the flue gas is lowered, so it is easier to contain (Simbeck & Roekpooritat, 2009).
- At low energy production rates (around 200MWe), an oxy-fuel combustion power plant costs about the same to operate as a traditional combustion power plant (including construction costs) (MIT, 2009).
Disadvantages: (Simbeck & Roekpooritat, 2009)
- Oxy-fuel capture plants are either just as or more costly as to maintain than traditional power plants.
- Research on manufacture, transportation, and handling of pure oxygen must still be done before oxy-fuel capture may be implemented on on a large scale.
- With this technology, a new plant's efficiency will decrease from 33.6% to 30.1%.
- $1644 million to build an average 500MWe plant (Simbeck, 2009)