INVESTIGATION OF AMMONIA AS A FUEL FOR SOLID OXIDE FUEL CELLS

Decreasing the generation of CO2 from energy production is a key area in energy research and environmental sustainability. Fuel cells represent a solution to reducing CO2 generation through the use of hydrogen fuel to generate electricity. However, the widespread use of hydrogen fueled fuel cells is generally limited by difficulty of hydrogen storage, transportation, and synthesis. One promising option to address these difficulties is the use of ammonia (NH3) in solid oxide fuel cells (SOFCs), which allows for storage of a liquid fuel source, rather than the highly compressed gaseous fuel. Sourcing hydrogen from ammonia rather than from fossil fuel reformation eliminates the possibility of CO2 generation from SOFC usage. Previous work has proven the ability to generate hydrogen from ammonia at high temperatures in a micro flow reactor (MFR) at high equivalence ratio. The current work seeks to apply a similar methodology directly to standard SOFCs for electricity generation. Construction of the planar SOFC includes a nickel-yttria stabilized zirconia (Ni-YSZ) anode, YSZ electrolyte layer, samarium doped ceria (SDC) electrolyte buffer layer, and lanthanum strontium cobalt ferrite-SDC (LSCF-SDC) cathode layer. A model ammonia exhaust based on the MFR exhaust for equivalence ratio of 4 from the previous work is used. A mixture of NH3, H2, and N2 simulates the MFR exhaust and is supplied to the SOFC. N2 is used to account for all MFR exhaust species outside of NH3 and H2. Testing is completed in a tubular furnace in order to maintain a controlled temperature, with oxygen being supplied to the cathode by ambient air. The buffer-layer SOFC showed high performance on pure H2 at 1V OCV and 343mW/cm² power density. The performance decreases on model exhaust, but maintains 0.9V OCV and 128mW/cm² power density. This showcases the ability of SOFCs to generate power from a NH3 supply that primarily contains N2.