1. MATHEMATICAL MODELING OF A MOLTEN-CARBONATE FUEL CELL USING MATHCAD
David Blekhman
Associate Professor
California State University, Los Angeles, CA, USA
Stephen T. McClain
Assistant Professor
Baylor University Waco, TX, USA

2. Molten-Carbonate Fuel Cell Operation
MCFC Operation
Very slow
Reactions provide specific mole count
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

3. Code Execution Block Diagram
Project
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

4. Project Description
Determine open cell voltage potential as reactants flow in a high-temperature fuel cell.
Project
In a molten-carbonate fuel cell
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

5. Fuel Reforming/Equilibrium
at inlet and through the fuel cell anode
Water-gas shift reaction
Steam-reforming reaction
Equilibrium constants, can be given or calculated
Fuel Reforming
Fuel is heated to the FC operational temperature. As the fuel cell reaction proceeds, the gas compositions on both the anode and cathode sides continuously change. For each mole of hydrogen reacted, one mole of water and one mole of carbon dioxide are generated on the anode. On the cathode, a half mole of oxygen and one mole of carbon dioxide disappear. This means that at each new step of the gas composition calculation, after all the corresponding moles of reactants on the anode are added and subtracted, the elements conservation coefficients Eqs. 14 and 15 are determined.
Three element conservation equations for H, O and C
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

6. Fuel Reforming/Equilibrium
at inlet and through the fuel cell anode
Fuel Reforming
Fuel is heated to the FC operational temperature. As the fuel cell reaction proceeds, the gas compositions on both the anode and cathode sides continuously change. For each mole of hydrogen reacted, one mole of water and one mole of carbon dioxide are generated on the anode. On the cathode, a half mole of oxygen and one mole of carbon dioxide disappear. This means that at each new step of the gas composition calculation, after all the corresponding moles of reactants on the anode are added and subtracted, the elements conservation coefficients Eqs. 14 and 15 are determined.
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

7. Fuel Reforming/Equilibrium
at inlet and through the fuel cell anode
Fuel Reforming
Fuel is heated to the FC operational temperature. As the fuel cell reaction proceeds, the gas compositions on both the anode and cathode sides continuously change. For each mole of hydrogen reacted, one mole of water and one mole of carbon dioxide are generated on the anode. On the cathode, a half mole of oxygen and one mole of carbon dioxide disappear. This means that at each new step of the gas composition calculation, after all the corresponding moles of reactants on the anode are added and subtracted, the elements conservation coefficients Eqs. 14 and 15 are determined.
Conjugate Gradient
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

8. Fuel Choices Fuel /Gas H2 H2O CO CO2 CH4 N2 Low-Btu 1, dry 71°C 0.213
0.193
0.104
0.011
0.479
Low-Btu 2, dry 60°C
0.402
0.399
0.199
Low-Btu 2, wet 60°C
0.336
0.164
0.333
0.166
Low-Btu 2, 650°C
0.2319
0.2673
0.0988
0.2344
0.0017
0.1668
Fuels and Oxidizers
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

9. Oxidizer Choices 1. 30% O2-60% CO2-10%N2 2. 30% O2-70% CO2
% O2-26% CO2-61%N2 --from air
Fuels and Oxidizers
Stoichiometry =0.5 (twice oxidizer)
Carbon dioxide =twice that of Oxygen
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

10. Fuel Flow Results Utilization David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

11. Fuel / Oxidizer Utilization
Fuel mixture composition as it flows through the fuel cell
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

12. Nernst Potential Nernst Potential
Open circuit potential as a function of fuel utilization in the fuel cell
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference

13. Topics Reviewed by the Project
Psychrometrics
Ideal Gas Mixtures
Reacting Systems
Chemical Equilibrium
Fuel Cells
Conclusions
David Blekhman, PhD
6th International Fuel Cell Science, Engineering and Technology Conference