How it Works

As in the figure, the building block of the SOFC is shown: each of these cells - consisting of an anode, electrolyte and cathode - can be connected and stacked up to provide any requirement of power. This modular build-up is what makes it possible for the SOFC to have practically constant efficiencies from Megawatt to single watt scal.

How the SOFC generates high-efficiency power and heat from fuel and air 

The fuel is fed to the anode side, where the high temperature allows it to be separated into its essential constituents. In hydrocarbons, these are hydrogen (H2) and carbon monoxide (CO). H2 and CO react in the same way at the anode. Taking H2 as an example, it reacts electrochemically to generate two electrons per molecule of hydrogen. This current is made to flow across the electrical load that needs to be powered, and reacts at the cathode side with the air - or the oxygen (O2) in particular - that is fed there. Every two electrons generate an oxygen ion, wich migrates across the gas-tight electrolyte to the anode, where it reacts with the hydrogen to release again the two electrons that generated the oxygen ion, effectively closing the circuit. In the process, the only by-product formed is water. In the case of CO, the by-product is CO2. The outlet of the SOFC therefore produces a clean and relatively pure mixture of water and carbon dioxide. Thus, if necessary, the carbon dioxide can be separeted and sequestered much more easily than is the case  with the by-product flows from combustion, where large quantities of nitrogen, contained in the air used for combustion, dilute the CO2 content and make it energy and cost-intesive to separate. Furthermore, the potential to generate clean water could make them attractive for areas and applications where water is in short supply.

 To turn the stack of cell to a fully functional power generating systems several auxiliary components (the so-called balance-of-plant, BOP) have to be integrated, taking care of fuel pre-treatment, power management and heat exchange.

In order to preserve the high efficiency of electrochemical conversion in the SOFC, the BOP often needs to be designed and produced specifically to optimize the integration and minimize parasitc losses. This is an important part of turning the SOFC to real, viable end-products.

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