Sulfur management and utilization in molten metal anode solid oxide fuel cells

Patent metadata

Field	Value
Publication number	US-9685675-B2
Application number	US-201414263442-A
Country	US
Kind code	B2
Filing date	Apr 28, 2014
Priority date	Apr 28, 2014
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Embodiments of a molten metal anode solid oxide fuel cell (MMA-SOFC) system comprise a first MMA-SOFC and a second MMA-SOFC, a fuel contactor integral with the first MMA-SOFC or in fluid communication with the first MMA-SOFC, a molten metal conduit configured to deliver molten metal from a first molten metal anode to a second molten metal anode, and one or more external electric circuits, wherein a first molten metal anode is configured to oxidize molten metal to produce metal oxides and electrons, the fuel contactor is configured to reduce the metal oxides and produce metals and metal sulfides in the molten metal upon reaction with sulfur-containing fuel. The second molten metal anode is configured to oxidize the metal sulfides in the metal sulfides-containing molten metal to produce metals and electrons, and the external electric circuits are configured to generate power from the electrons produced in the first and second MMA-SOFCs.

First claim

What is claimed is:

1. A molten metal anode solid oxide fuel cell (MMA-SOFC) system comprising:
a first MMA-SOFC comprising a first cathode, a first molten metal anode, and a first solid electrolyte disposed between the first cathode and the first molten metal anode;
a second MMA-SOFC comprising a second cathode, a second molten metal anode, and a second solid electrolyte disposed between the second cathode and the second molten metal anode;
a molten metal conduit configured to deliver molten metal from the first molten metal anode to the second molten metal anode;
a fuel contactor integral with the first MMA-SOFC or in fluid communication with the first MMA-SOFC; and
one or more external electric circuits, wherein
the first molten metal anode comprises an oxidation region configured to oxidize the molten metal to produce metal oxides and electrons, and
the fuel contactor comprises a regeneration region configured to reduce the metal oxides and produces metal sulfides in the molten metal upon reaction with sulfur-containing fuel;
the second molten metal anode is configured to oxidize the metal sulfides in the metal sulfides-containing molten metal to produce metals and electrons; and
the external electric circuits are configured to generate power from the electrons produced in both the first MMA-SOFC and the second MMA-SOFC; and wherein a solid metal anode is disposed between the second molten metal anode and the second solid electrolyte.

2. The system of claim 1 wherein the second solid metal anode comprises metals or metal-ceramics.

3. The system of claim 1 wherein the second solid metal anode comprises metal selected from the group consisting of iron (Fe), copper (Cu), nickel (Ni), cobalt (Co), and combinations thereof.

4. The system of claim 1 wherein the first molten metal anode, the second molten metal anode, or both comprises metal selected from the group consisting of tin (Sn), bismuth (Bi), indium (In), lead (Pb), antimony (Sb), copper (Cu), molybdenum (Mo), mercury (Hg), iridium (Ir), palladium (Pd), rhenium (Re), platinum (Pt), silver (Ag), arsenic (As), rhodium (Rh), tellurium (Te), selenium (Se), osmium (Os), gold (Au), germanium (Ge), thallium (Tl), cadmium (Cd), gadolinium (Gd), chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), cobalt (Co), zinc (Zn), vanadium (V), and combinations thereof.

5. The system of claim 1 wherein the first molten metal anode, the second molten metal anode, or both comprises antimony.

6. The system of claim 1 wherein the first solid electrolyte, the second solid electrolyte, or both comprises zirconia-based electrolytes or ceria-based electrolytes.

7. The system of claim 6 wherein the zirconia-based electrolytes are selected from the group consisting of yttria stabilized ZrO 2 (YSZ), scandia stabilized ZrO 2 (ScSZ), calcia stabilized ZrO 2 (CSZ) and combinations thereof.

8. The system of claim 6 wherein the ceria-based electrolytes comprise rare earth doped ceria.

9. The system of claim 6 wherein the ceria-based electrolytes are selected from the group consisting of gadolinium doped ceria (GDC), yttria doped ceria (YDC), samarium doped ceria (SmDC), and combinations thereof.

10. The system of claim 1 wherein the first solid electrolyte, the second solid electrolyte, or both comprises of yttria stabilized ZrO 2 (YSZ).

11. The system of claim 1 wherein the first cathode, the second cathode, or both is selected from the group consisting of lanthanum strontium manganite (LSM), yttria stabilized ZrO 2 /lanthanum strontium manganite (YSZ-LSM), lanthanum strontium cobalt ferrite (LSCF), and combinations thereof.

12. The system of claim 1 further comprising a fuel contactor in fluid communication with the first molten metal anode and the second molten metal anode.

13. The system of claim 12 wherein the fuel contactor comprises a porous ceramic, metal, or combinations thereof.

14. The system of claim 1 further comprising a sacrificial reducing agent downstream of the second molten metal anode and configured to reduce the metal oxides to metal.

15. The system of claim 14 wherein the sacrificial reducing agent is a graphite rod or one selected from the group consisting of iron (Fe), zirconium (Zr), manganese (Mn), tantalum (Ta), silicon (Si) or titanium (Ti) and combinations thereof.

16. The system of claim 1 further comprising SO 2 removal and treatment equipment downstream of the second molten metal anode.

17. The system of claim 16 wherein the SO 2 removal and treatment equipment comprises one or more units selected from the group consisting of a wet scrubber unit, a spray-dry unit, a wet H 2 SO 4 processing unit, a SNO X flue-gas desulfurization unit, and combinations thereof.

18. The system of claim 1 further comprising a catalytic section of a Claus unit downstream of the second molten metal anode, the catalytic section of the Claus unit being configured to utilize SO 2 byproduct to catalytically convert H 2 S to elemental sulfur.

19. The system of claim 1 further wherein the sulfur-containing fuel is selected from the group consisting of hydrogen fuel, carbon fuel, hydrocarbon fuel, hydrogen sulfide, and mixtures thereof.

20. The system of claim 1 wherein the fuel contactor is integrated into the first MMA-SOFC.

21. The system of claim 1 wherein the fuel contactor is separate but in fluid communication with the first MMA-SOFC.

22. The system of claim 1 further comprising an additional fuel contactor in fluid communication with the second molten metal anode, wherein the additional fuel contactor comprises a sulfation region configured to produce metal sulfides in the molten metal.

23. A molten metal anode solid oxide fuel cell system (MMA-SOFC) comprising:
a first MMA-SOFC comprising a first cathode, a first molten metal anode, and a first solid electrolyte disposed between the first cathode and the first molten metal anode, wherein the first molten metal anode is configured to oxidize molten metal to produce metal oxides and electrons;
a second MMA-SOFC comprising a second cathode, a second molten metal anode, and a second solid electrolyte disposed between the second cathode and the second molten metal anode;
a fuel contactor in fluid communication with the first MMA-SOFC and the second MMA-SOFC;
a molten metal conduit configured to deliver molten metal between the first molten metal anode, the second molten metal anode, and the fuel contactor; and
one or more external electric circuits configured to generate power from the electrons produced in both the first MMA-SOFC and the second MMA-SOFC, wherein,
the fuel contactor comprises a regeneration region configured to reduce the metal oxides and produces metal sulfides in the molten metal upon reaction with sulfur-containing fuel and a sulfation region configured to produce metal sulfides from metals in molten metal delivered by the second molten metal anode, and
the second molten metal anode is configured to oxidize metal sulfides in metal sulfides-containing molten metal to produce metals and electrons; and wherein a solid metal anode is disposed between the second molten metal anode and the second solid electrolyte.

24. The system of claim 23 wherein the molten metal conduit is configured to recycle metal sulfides produced in the sulfation region of the fuel contactor back to the second molten metal anode.

25. The system of claim 23 wherein the molten metal conduit is configured to r

Assignees

• Saudi Arabian Oil Co

Inventors

• Souentie Stamatios
• Dawsari Yasmeen A
• Hamad Esam Zaki

Classifications

• H01M4/9033

  Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites · CPC title

• H01M4/905

  specially used in fuel cell operating at high temperature, e.g. SOFC · CPC title

• H01M8/1246 Primary

  the electrolyte consisting of oxides · CPC title

• Y02P70/56

  Cross-Sectional Technologies · mapped topic

• H01M8/22

  Fuel cells in which the fuel is based on materials comprising carbon or oxygen or hydrogen and other elements; Fuel cells in which the fuel is based on materials comprising only elements other than carbon, oxygen or hydrogen · CPC title