Molten carbonate fuel cell

The molten carbonate fuel cell ( molten carbonate fuel cell Sheet, MCFC ) is a high temperature fuel cell, which operates at an operating temperature between 580 ° C and 675 ° C. As an electrolyte, this type of cell uses a mixed alkali carbonate melt of lithium carbonate and potassium carbonate.

Principle

The fuel gas is a mixture of hydrogen and carbon monoxide is used on the side of the anode, which is produced by internal reforming of a methane-containing fuels such as fossil natural gas or biogas. Reaction products formed on the anode side of the water and carbon dioxide. The cathode side, oxygen and carbon dioxide is added, the latter is returned from the anode exhaust gas. The oxygen combines with electrons recording with the CO2 into a carbonate ion, which migrates through the electrolyte.

The materials for building this type of cell are relatively cheap, since it works in a temperature range at which an acceptable reaction rate without expensive noble metal catalysts is achieved and cheaper nickel electrodes can be used. On the other hand, the operating temperature is not so high, so it can be without expensive high-temperature materials. Difficult type is mainly because of deterioration due to the constant heating up to high temperatures and cooling the system. The toxicity and flammability of hydrogen-rich and CO-containing reformate from the internal reforming is high but manageable demands on safety.

The molten carbonate fuel cell can reach an electrical system efficiency of about 45% to 50%. When used as a cogeneration unit with simultaneous local heating use an overall efficiency up to 90 % can be achieved. The MCFC is can be used in the future in the local and larger power plants.

Reaction equations

Steam reforming reaction with Shift