Derivation of control parameters of fuel cell systems for flexible fuel operation

1. A method of operating a fuel cell system, comprising:

characterizing a fuel being provided into the fuel cell system, wherein the step of characterizing the fuel comprises obtaining a measure of a quantity of a constituent in a sample of the fuel; and

calculating a fuel utilization based on the step of characterizing the fuel,

wherein the fuel utilization is calculated according to the following formula:

Fuel Utilization (%)=100%*((Average Cell Current (in Amps)*Number of Cells)/F)/((4*(mol C atoms/mol fuel)+(mol H atoms/mol Fuel)−2*(mol O atoms/mol Fuel)−(4*(% O2)/100%)*CPOx flow (in mol/sec)).

2. The method of claim 1 , wherein:

the fuel cell system comprises an anode side that receives the fuel;

an oxidizing gas is being provided into the anode side of the fuel cell system;

the oxidizing gas is characterized by obtaining a measure of a quantity of a constituent in a sample of the oxidizing gas;

the oxidizing gas being provided into the anode side of the fuel cell system is air;

local atmospheric information is used for said characterizing the oxidizing gas; and

said local atmospheric information comprises ambient temperature, ambient pressure and relative humidity of the air.

3. The method of claim 1 , wherein said fuel comprises a fuel comprising carbon and hydrogen.

4. The method of claim 3 , wherein said fuel is selected from the group consisting of methane, natural gas, propane, alcohol, or syngas derived from coal or natural gas reformation and wherein obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining a composition of the fuel based on at least one of location or time of year.

5. The method of claim 1 , further comprising:

characterizing a mixture of two or more fuels being provided into the anode side of the fuel cell system, wherein obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining a measure of a quantity of a constituent in a sample of the fuel mixture; and

calculating the fuel utilization based on the step of characterizing the fuel mixture.

6. The method of claim 5 , wherein the fuel mixture comprises two or more fuels with distinct carbon contents, hydrogen contents, and/or oxygen contents.

7. The method of claim 6 , wherein:

the fuel cell system comprises an anode side that receives the fuel;

an oxidizing gas is being provided into the anode side of the fuel cell system;

the oxidizing gas is characterized by obtaining a measure of a quantity of a constituent in a sample of the oxidizing gas;

said oxidizing gas comprises air;

local atmospheric information is used to characterize said air; and

said local atmospheric information comprises ambient temperature, ambient pressure and relative humidity.

8. The method of claim 2 , further comprising:

providing the fuel and the oxidizing gas to the anode side of the fuel cell system based on the calculated fuel utilization; and

generating electricity using the fuel cell system.

9. The method of claim 1 , wherein obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining at least one of moles of carbon per gram or milliliter or mole of fuel, moles of hydrogen per gram or milliliter or mole of fuel, moles of oxygen per gram or milliliter or mole of fuel.

10. The method of claim 2 , wherein:

obtaining the measure of a quantity of the constituent in the sample of the oxidizing gas comprises obtaining at least one of temperature, ambient pressure, or relative humidity from a source of weather data; and

obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining the fuel characteristics from the fuel supply source or by measuring or testing the fuel.

11. The method of claim 2 , wherein said step of characterizing the oxidizing gas utilizes the ambient pressure, temperature and relative humidity to derive at least one of the oxygen, nitrogen or water content of the air.

12. The method of claim 1 , wherein said fuel cell system is a solid-oxide fuel cell system.

13. The method of claim 1 , wherein a computer or a logic device performs the step of calculating.

14. A method of operating a fuel cell system, comprising:

characterizing a fuel being provided into the fuel cell system, wherein said fuel comprises a fuel comprising carbon and hydrogen and wherein characterizing the fuel comprises obtaining a composition of the fuel based on at least one of location or time of year;

characterizing an oxidizing gas being provided into the fuel cell system, wherein:

the oxidizing gas being provided into the fuel cell system is air;

local atmospheric information is used for said characterizing the oxidizing gas; and

said local atmospheric information comprises ambient temperature, ambient

pressure and relative humidity of the air; and

calculating at least one of steam:carbon (S:C) ratio, fuel utilization and oxidizing gas utilization based on the steps of characterizing the fuel and the oxidizing gas.

15. A method of operating a fuel cell system, comprising:

characterizing a mixture of two or more fuels being provided into the fuel cell system, wherein said two or more fuels have distinct carbon contents, hydrogen contents, and/or oxygen contents and wherein the step of characterizing the fuel mixture comprises obtaining a measure of a quantity of a constituent in a sample of the fuel;

characterizing an oxidizing gas being provided into the fuel cell system, wherein said oxidizing gas comprises air, wherein the step of characterizing the oxidizing gas comprises obtaining a measure of a quantity of a constituent in a sample of the oxidizing gas based on local atmospheric information and wherein said local atmospheric information comprises ambient temperature, ambient pressure and relative humidity; and

calculating at least one of steam:carbon (S:C) ratio, fuel utilization and oxidizing gas utilization based on the steps of characterizing the fuel and the oxidizing gas.

16. The method of claim 2 , wherein the oxidizing gas is being provided through a catalytic partial oxidation reactor with the fuel.

17. The method of claim 14 , wherein:

the fuel cell system comprises an anode side that receives the fuel;

the oxidizing gas is provided into the anode side of the fuel cell system through a catalytic partial oxidation reactor with the fuel; and

the step of calculating comprises calculating the fuel utilization.

18. The method of claim 15 , wherein:

the fuel cell system comprises an anode side that receives the fuels;

the oxidizing gas is being provided into the anode side of the fuel cell system through a catalytic partial oxidation reactor with the fuels; and

the step of calculating comprises calculating the fuel utilization.

19. A method of operating a fuel cell system, wherein the fuel cell system comprises an anode side that receives the fuel, the method comprising:

characterizing a fuel being provided into the fuel cell system, wherein the step of characterizing the fuel comprises obtaining a measure of a quantity of a constituent in a sample of the fuel;

characterizing an oxidizing gas being provided into the anode side of the fuel cell system, wherein the oxidizing gas is air, wherein the step of characterizing the oxidizing gas comprises:

obtaining a measure of a quantity of a constituent in a sample of the oxidizing gas;

obtaining local atmospheric information comprising ambient temperature, ambient pressure and relative humidity of the air; and

characterizing the constituent in the sample using the measure and the local atmospheric information; and

calculating a fuel utilization based on the steps of characterizing the fuel and characterizing the oxidizing gas.

20. The method of claim 19 , further comprising:

characterizing a mixture of two or more fuels being provided into the anode side of the fuel cell system, wherein obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining a measure of a quantity of a constituent in a sample of the fuel mixture; and

calculating the fuel utilization based on the step of characterizing the fuel mixture.

21. The method of claim 20 , wherein the fuel mixture comprises two or more fuels with distinct carbon contents, hydrogen contents, and/or oxygen contents.

22. The method of claim 19 , further comprising:

providing the fuel and the oxidizing gas to the anode side of the fuel cell system based on the calculated fuel utilization; and

generating electricity using the fuel cell system.

23. The method of claim 19 , wherein:

obtaining the measure of a quantity of the constituent in the sample of the oxidizing gas comprises obtaining at least one of temperature, ambient pressure, or relative humidity from a source of weather data; and

obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining the fuel characteristics from the fuel supply source or by measuring or testing the fuel.

24. The method of claim 19 , wherein said step of characterizing the oxidizing gas utilizes the ambient pressure, temperature and relative humidity to derive at least one of the oxygen, nitrogen or water contents of the air.

25. A method of operating a fuel cell system, comprising:

characterizing a fuel being provided into the fuel cell system,

wherein said fuel comprises a fuel comprising carbon and hydrogen,

wherein said fuel is selected from the group consisting of methane, natural gas, propane, alcohol, and syngas derived from coal or natural gas reformation,

wherein the step of characterizing the fuel comprises obtaining a measure of a quantity of a constituent in a sample of the fuel, and

wherein obtaining the measure of a quantity of the constituent in the sample of the fuel comprises obtaining a composition of the fuel based on at least one of location or time of year; and

calculating a fuel utilization based on the step of characterizing the fuel.