Direct carbon fuel cell
A Direct Carbon Fuel Cell (DCFC) is a fuel cell that uses a carbon rich material as a fuel. The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product. The efficiency of this fuel cell is about 70% (twice as efficient as a conventional combustion reaction).
The total reaction of the cell is C + O2 → CO2. The process in half cell notation:
• Anode: C + 2 O2- → CO2 + 4 e-
• Cathode: O2 + 4 e- → 2 O2-
Despite this release of carbon dioxide, the direct carbon fuel cell is more environmentally friendly than traditional carbon burning techniques. Due to its higher efficiency, it requires less carbon to produce the same amount of energy. Utilized carbon can be in the form of coal, coke, char, or a non-fossilized source of carbon. Due to the higher charge state of the carbon atoms, the current density at the carbon anode is doubled compared to hydrogen gas molecules, giving it a beneficial energy to weight ratio as well.
Three types of DCFC exist:
• The first one is based on the Solid oxide fuel cell (SOFC) concept.
• The second one is based on the Molten Carbonate Fuel Cell (MCFC) concept. William W. Jacques obtained a Canadian patent in this type of fuel cell in 1897.
• The third is a molten tin anode solid oxide fuel cell design, which utilizes molten tin and tin oxide as an inter stage reaction between oxidation of the carbon dissolving in the anode and reduction of oxygen at the solid oxide cathode.
Last Update: Monday 6 April 2009 Time: 14:12