Molten Carbonate Fuel Cells – MCFC
The MCFC operates at high temperature ranges of 580 to 660°C.
The advantage of this type of cell is that there is no need for gas purification. In addition the cell is insensitive to carbon monoxide poisoning.
Natural gas, coal gas, biogas and synthesis gas can be used directly as fuels. No reformer is needed.
The electrolyte in this fuel cell is a salt melting of combined alkali carbonates (Li2CO3 / K2CO3).
The function of the MCFC:
- Step 1
There are two seperate gas supply systems. At the cahode area there is oxygene and carbon dioxide. At the anode area there is hydrogen. The gas flow touches the catalyzer.
- Step 2
The hydrogen molecules are splitted into two H+ protons at the catalyzer. Each hydrogen atom sets one electron free.
- Step 3
The electrons move from the anode to the cathode and cause an electric current. This electric current supplies an electric capacitor with electriv power
- Step 4
Respectively four electrons recombine with one hydrogen molecule at the cathode.
- Step 5
The now generated oxygene ions have a negative load and react with carbon dioxide into carbonate ions.
- Step 6
The negative loaded carbonate ions move through the electrolyte (molten carbonate) into the direction of the positive loaded protons at the anode side.
- Step 7
The carbonate ions change their negative loads with two protons and oxidize with them to water. Because of the split off of the oxygene ions from the carbonate, carbon dioxide is generated again.
Molten carbonate fuel cells are being developed for stationary applications. They are especially useful for the cogeneration of power and heat in industrial and commercial applications where high temperatures are required (process heat) because the MCFC operates at temperatures around 650°C.
Plants with around 300 kW power rating are in the development but plants with more power are also possible. Apart from these stationary applications ship engines on the basis of MCFCs are being developed as well.