Case Study Design Concepts And Fabrication Of Sofcs
Case Study Design Concepts and Fabrication of SOFCs
Rory King 0532103
Executive Summary
Aim:
· Describe how fuel cells and specifically solid oxide fuel cells operate.
· Describe, compare and contrast two design concepts for solid oxide fuel cells capable of operation in the temperature range 800-1000ºC.
· Outline a fabrication route for each of my design concepts.
· Suggest suitable materials for each of the functional components.
What is a fuel cell?
Fuel cells are electrochemical devices that convert chemical energy from a reaction directly into electrical energy. A general fuel cell will comprise of an electrolyte block sandwiched between a porous cathode and anode. Gaseous fuels are fed in at the negatively anode, and oxygen at the positive cathode, the electrochemical reactions take place at the electrodes creating the electric current.
This schematic diagram shows the general reactions in a fuel cell. Here the fuel is Hydrogen gas and the only waste product is water. In other fuel cell systems, Carbon monoxide and methane can be used as the fuel, but reactions of these fuels have different by-products.
At the cathode negatively charged oxygen ions are produced by the reduction of oxygen:
O2(g) + 4e- 2O22-
These oxygen ions will cross the ionically conductive electrolyte to the anode where they will react with the fuel, in this case either H2 or CO:
H2(g) + O2- H2O(g) + 2e-
CO(g) + O2- CO2(g) + 2e-
The extra electrons give the desired potential difference between the anode and cathode.
This reaction also produces heat which must be controlled, this can be done by generating extra electricity through steam turbines.
What is a Solid Oxide Fuel Cell (SOFC)?
SOFCs are an advanced type of all-ceramic fuel cell which...
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