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1. WO2020113242 - ANODE EXHAUST PROCESSING FOR MOLTEN CARBONATE FUEL CELLS

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[ EN ]

CLAIMS:

1. A method for producing electricity using a molten carbonate fuel cell comprising an anode and a cathode, the method comprising:

operating the molten carbonate fuel cell with a cathode input stream comprising CO2 and O2 to generate i) electricity at a current density of 60 mA/cm2 or more, ii) an anode exhaust comprising H2, CO, and CO2, and iii) a cathode exhaust comprising 2.0 vol% or less CO2, 1.0 vol% or more H2O, and 1.0 vol% or more O2; and

oxidizing at least a portion of the H2 and CO in the anode exhaust in the presence of a metal oxide oxidizer.

2. The method of claim 1, wherein at least a portion of the metal oxide oxidizer is converted into metal, a reduced oxidation state metal oxide, or a combination thereof, the method further comprising oxidizing at least a portion of the converted metal, reduced oxidation state metal oxide, or a combination thereof to form the metal oxide oxidizer, and wherein the cathode exhaust optionally further comprising O2, the at least a portion of the converted metal, reduced oxidation state metal oxide, or a combination thereof optionally being oxidized using at least a portion of the cathode exhaust.

3. The method of claim 2, wherein oxidizing the converted metal, reduced oxidation state metal oxide, or a combination thereof to the metal oxide oxidizer generates heat, the generated heat being used for generation of electrical power, the generated heat optionally being used to generate steam that is passed into a heat recovery steam generator.

4. The method of claim 2 or 3, the method further comprising:

determining a requested load;

accumulating the metal, reduced oxidation state metal oxide, or a combination thereof when the requested load is below a threshold value; and

oxidizing at least a portion of the converted metal, reduced oxidation state metal oxide, or a combination thereof to the metal oxide oxidizer when the requested load is greater than a second threshold value.

5. The method of any of the above claims, wherein the cathode input stream comprises 5.0 vol% or less CO2, or wherein the cathode exhaust comprises 1.0 vol% or less CO2, or a combination thereof.

6. The method of any of the above claims, wherein the molten carbonate fuel cell is operated at a transference of 0.95 or less, or wherein the molten carbonate fuel cell is operated at a CO2 utilization of 75% or more, or a combination thereof.

7. The method of any of the above claims, wherein the voltage drop across the cathode is 0.4

V or less, or wherein the electricity is generated at a voltage of 0.55 V or more, or a combination thereof.

8. The method of any of the above claims, wherein a Ha concentration in the anode exhaust is 5.0 vol% or more, or wherein a combined concentration of Ha and CO in the anode is exhaust is 6.0 vol% or more, or a combination thereof.

9. The method of any of the above claims, wherein the metal oxide oxidizer comprises iron oxide, manganese oxide, nickel oxide, copper oxide, or a combination thereof.

10. The method of any of the above claims, wherein the at least a portion of the Ha and CO in the anode exhaust is oxidized in the presence of a fixed bed comprising the metal oxide oxidizer, a fluidized bed comprising the metal oxide oxidizer, or a combination thereof.

11. A combined cycle power system, comprising:

a gas turbine comprising a combustion zone, and a turbine outlet;

a plurality of molten carbonate fuel cells comprising fuel cell cathodes, fuel cell anodes, a cathode exhaust outlet, and an anode exhaust outlet, the fuel cell cathodes being in fluid communication with the combustion zone via the turbine outlet;

a plurality of chemical looping combustion reactors including one or more first reactors comprising metal oxide particles and one or more second reactors comprising reduced oxidation state metal oxide particles, metal particles, or a combination thereof, at least one first reactor being in fluid communication with the anode exhaust outlet; and

a heat recovery steam generator in fluid communication with at least one second reactor.

12. The combined cycle power system of claim 11, further comprising a second heat recovery steam generator in fluid communication with an outlet of the at least one first reactor.

13. The combined cy cle power system of claim 11 or 12, further comprising a third heat recovery steam generator, the fuel cell cathodes being in fluid communication with the combustion zone via the turbine outlet and via the third heat recovery steam generator.

14. The combined cycle power system of any of claims 11 to 13, wherein tire metal oxide comprises iron oxide, manganese oxide, nickel oxide, copper oxide, or a combination thereof.

15. The combined cycle power system of any of claims 11 to 14, wherein the plurality of chemical looping combustion reactors comprise fixed bed reactors, fluidized bed reactors, or a combination thereof.