Carbon gasification assisted solid oxide electrolysis cell
A syngas generation system that combines a solid oxide electrolysis cell (SOEC) and a carbon gasification unit is described. On the cathode side of the SOEC, CO 2 and H 2 O are electrochemically converted to syngas. At the anode side of the system, a second stream of syngas is produced through a carbon gasification process in which solid carbon is reacted with H 2 O/CO 2 . Oxygen ion transported across the SOEC electrolyte reacts at the anode with a portion of the syngas produced in the gasification process. This reaction product (H 2 O/CO 2 ) can be fed back to the gasification unit.
1. A syngas generation system, comprising:
a solid oxide electrolysis cell comprising a cathode, an anode, and an electrolyte between the cathode and the anode; and
a carbon gasification unit in fluid communication with the anode, the gasification unit comprising a gasification chamber that is configured to operate at substantially atmospheric pressure.
2. The syngas generation system of claim 1 , further comprising a power supply configured to provide a voltage potential across the cathode and the anode.
3. The syngas generation system of claim 1 , further comprising a feed line to the cathode configured to deliver carbon dioxide and water to the cathode.
4. The syngas generation system of claim 3 , further comprising a heating system in contact with the feed line.
5. The syngas generation system of claim 1 , the cathode comprising a nickel-zirconia cermet.
6. The syngas generation system of claim 1 , wherein the electrolyte is an oxygen ion-conducting solid electrolyte.
7. The syngas generation system of claim 1 , wherein the anode comprises a carbon monoxide resistant material.
8. The syngas generation system of claim 7 , wherein the carbon monoxide resistant anode material includes Sr 2 Fe 1.5 Mo 0.5 O 6-δ , or La 0.7 Ca 0.3 Cr 0.97 O 3 .
9. The syngas generation system of claim 1 , the system comprising an array of solid oxide electrolysis cells.
10. A method for generating syngas comprising:
electrochemically reducing water and carbon dioxide at a cathode to produce a first syngas product and oxygen ion, the oxygen ion migrating across an electrolyte adjacent to the cathode and thence to an anode;
reacting a solid carbon with carbon dioxide and water at a gasification unit to produce a second syngas product;
delivering at least a portion of the second syngas product to the anode such that carbon monoxide and hydrogen gas of the second syngas react with the oxygen ion to produce carbon dioxide and water;
delivering at least a portion of the carbon dioxide and water produced at the anode to the gasification unit.
11. The method of claim 10 , further comprising feeding the water and the carbon dioxide to the cathode as a single feed stream.
12. The method of claim 11 , further comprising heating the single feed stream to provide the water to the cathode as steam.
13. The method of claim 12 , wherein the single feed stream is heated with energy generated from a renewable energy source or waste heat.
14. The method of claim 12 , wherein the single feed stream is provided to the cathode at temperature of from about 773 K to about 1273 K.
15. The method of claim 10 , further comprising providing a voltage potential across the cathode and the anode.
16. The method of claim 15 , the voltage potential increasing an oxygen ion transport rate across the electrolyte.
17. The method of claim 10 , wherein the carbon dioxide and the water are provided to the cathode at a ratio such that the first syngas product includes hydrogen gas and carbon monoxide at a ratio of about 2 to 1.
18. The method of claim 10 , wherein the solid carbon is obtained from a carbon source selected from peat, coke, coal, char, petroleum coke, tar sand, oil sand, waste plastics, biomass or carbon produced by pyrolysis of carbonaceous substance.