Integrated CPOX/stream reformer and fuel cell system
A high efficiency fuel reforming and/or electricity generating system and method utilizes the heat generated by CPOX reforming and or fuel cell operation as an energy source to drive steam reforming. Enhanced efficiencies of over 10%, 35%, 40%, and even over 50-55% can be achieved. A CPOX reformer generates hydrogen. A fuel cell converts this hydrogen into electricity, heat and steam. A secondary fuel line can be combined with the heat and steam generated by the fuel cell and steam reform the secondary fuel into additional hydrogen. This additional hydrogen can be used to generate additional electricity, creating even more heat and steam.
1. A method of combined CPOX and steam reforming, comprising:
flowing a first reformable fuel stream and an oxygen containing gas stream into an inlet of a CPOX reaction zone of a CPOX reactor containing a CPOX catalyst, and at least partially reforming the first reformable fuel stream and generating a heat of exotherm and a reaction product stream exiting an outlet of the CPOX reaction zone, the reaction product stream including a first amount of hydrogen;
flowing a second reformable fuel stream through the CPOX reaction zone, isolating the second reformable fuel stream from the CPOX catalyst, and not reforming the second reformable fuel stream within the CPOX reaction zone;
flowing the reaction product stream into an inlet of a fuel cell, and generating a first amount of electricity, heat and steam with the fuel cell;
flowing the secondary fuel stream into the fuel cell and steam reforming the second reformable fuel stream with the heat and steam generated by the fuel cell and producing a second amount of hydrogen.
2. The method of claim 1 , wherein the CPOX reaction zone comprises an open gas flow passageway defined by a wall containing the CPOX catalyst, wherein the first reformable fuel stream and the oxygen containing gas diffuse into the CPOX catalyst containing wall and the reaction product diffuses back into the open gas flow passageway.
3. The method of claim 2 , wherein the second reformable fuel stream flows through the CPOX reaction zone within a conduit extending through the open gas flow passageway.
4. The method of claim 3 , wherein the conduit has an outlet and the conduit outlet extends past a downstream end of the outlet of the CPOX reaction zone and past an upstream end of an inlet of the fuel cell.
5. The method of claim 3 , wherein an outside surface of the conduit within the CPOX reaction zone is at least partially covered with a layer of CPOX catalyst and some of the first reformable fuel stream diffuses into the layer of CPOX catalyst on the conduit and forms a second reaction product, which diffuses back into the open gas flow passageway.
6. The method of claim 3 , wherein the CPOX reaction zone comprises a perovskite-containing wall structure.
7. The method of claim 3 , wherein a cross sectional area of the conduit occupies less than 20% of a cross sectional area of the open gas flow passageway.
8. The method of claim 2 , wherein there is a hydrogen barrier outside the wall preventing substantially any loss of hydrogen therethrough.
9. The method of claim 8 , wherein the hydrogen barrier comprises a layer of metal.
10. The method of claim 1 , wherein the fuel cell reacts the second amount of hydrogen and generates a second amount of electricity, heat and steam.
11. The method of claim 10 , wherein the efficiency of the conversion of the reformable fuel into electricity is at least 35% higher than the efficiency of the same method of CPOX reforming without the step of steam reforming the secondary fuel stream.
12. The method of claim 10 , wherein the second amount of electricity is at least 10% of the first amount of electricity.
13. The method of claim 10 , wherein the second amount of electricity is at least 33% of the first amount of electricity.
14. The method of claim 1 , wherein the molar ratio of the second reformable fuel stream to the first reformable fuel stream is at least 1:9.
15. The method of claim 1 , wherein the molar ratio of the second reformable fuel stream to the first reformable fuel stream is at least 4:6.