Electrochemical system having multiple independent circuits
View Patent ↗The present teachings relate to an electrochemical system including an electrochemical device and multiple independent circuits which permit independent control of the reaction rates at different sections of the electrochemical device. The electrochemical device can be a fuel cell or an electrolyzer, and can include a common electrode in electrical communication with two or more independent circuits. The present teachings also relate to operating methods of the electrochemical system described.
1. A method of operating a fuel cell, the method comprising:
providing a tubular fuel cell having a length divided into a front end and a back end, wherein the tubular fuel cell comprises an anode extending from the front end to the back end, a first cathode extending within the front end, a second cathode extending within the back end, and an electrolyte separating the anode from each of the first cathode and the second cathode;
providing a first loading device that is electrically connected to the first cathode and the anode in a first electrical circuit;
providing a second loading device that is electrically connected to the second cathode and the anode in a second electrical circuit;
introducing a fuel along the anode from the front end of the tubular fuel cell to the back end of the tubular fuel cell; and
varying independently a first electrical load applied by the first loading device to the first electrical circuit and a second electrical load applied by the second loading device to the second electrical circuit, such that during operation of the tubular fuel cell, the electrical potential across the front end of the tubular fuel cell is different from the electrical potential across the back end of the tubular fuel cell.
2. The method of claim 1 comprising applying the first electrical load and the second electrical load simultaneously, wherein the first electrical load and the second electrical load are different.
3. The method of claim 1 comprising applying the first electrical load and the second electrical load out-of-phase.
4. The method of claim 1 , wherein an oxidant is introduced alternatively to the first cathode and the second cathode.
5. The method of claim 1 further comprising controlling the first loading device and the second loading device with a microprocessor capable of being programmed to vary the first electrical load and the second electrical load independently and at different times.
6. The method of claim 1 , wherein the electrical potential across the front end of the tubular fuel cell and the electrical potential across the back end of the tubular fuel cell independently are between 0.3 V and the open circuit voltage of the tubular fuel cell.
7. The method of claim 6 comprising applying the first electrical load and the second electrical load out-of-phase, such that at alternating points of time, the electrical potential across either the front end or the back end of the tubular fuel cell is the open circuit voltage of the tubular fuel cell while the electrical potential across the other end of the tubular fuel cell is at least 0.3 V but less than the open circuit voltage of the tubular fuel cell.
8. The method of claim 6 comprising applying the first electrical load and the second electrical load simultaneously, wherein the first electrical load and the second electrical load are different and the electrical potential across the front end of the tubular fuel cell and the electrical potential across the back end of the tubular fuel cell independently are at least 0.3 V but less than the open circuit voltage of the tubular fuel cell.
9. The method of claim 1 , wherein the tubular fuel cell comprises a monolith structure.
10. The method of claim 1 , wherein the tubular fuel cell comprises an anode-supported structure.
11. The method of claim 1 , wherein the tubular fuel cell is a solid oxide fuel cell.
12. The method of claim 11 , wherein the electrolyte is composed of yttria-stabilized zirconia.
13. The method of claim 11 , wherein the anode is composed of a cermet comprising nickel and yttria-stabilized zirconia.
14. The method of claim 11 , wherein the cathode is composed of a perovskite.
15. A method of operating a fuel cell, the method comprising:
providing a fuel cell having a length divided into a front end and a back end, wherein the fuel cell comprises an anode extending along the entire length of the fuel cell, a first cathode extending within the front end, a second cathode extending within the back end, and an electrolyte separating the anode from each of the first cathode and the second cathode;
providing a first loading device that is electrically connected to the first cathode and the anode in a first electrical circuit;
providing a second loading device that is electrically connected to the second cathode and the anode in a second electrical circuit;
introducing a fuel along the anode from the front end of the fuel cell to the back end of the fuel cell; and
varying independently a first electrical load applied by the first loading device to the first electrical circuit and a second electrical load applied by the second loading device to the second electrical circuit, such that during operation of the fuel cell, the electrical potential across the front end of the fuel cell is different from the electrical potential across the back end of the fuel cell.
16. The method of claim 15 , wherein the fuel cell is a tubular fuel cell.
17. The method of claim 16 , wherein the anode extending along the entire length of the fuel cell is a common supporting anode.
18. The method of claim 15 , wherein the anode extending along the entire length of the fuel cell is a common supporting anode.
19. The method of claim 15 further comprising controlling the first loading device and the second loading device with a microprocessor capable of being programmed to vary the first electrical load and the second electrical load independently and at different times.
20. A method of operating a fuel cell, the method comprising:
providing a tubular solid oxide fuel cell having a length divided into a front end and a back end, wherein the tubular solid oxide fuel cell comprises a common anode extending along the entire length of the tubular solid oxide fuel cell, a first cathode extending within the front end, a second cathode extending within the back end, and an electrolyte separating the common anode from each of the first cathode and the second cathode;
providing a first loading device that is electrically connected to the first cathode and the common anode in a first electrical circuit;
providing a second loading device that is electrically connected to the second cathode and the common anode in a second electrical circuit;
introducing a fuel along the common anode from the front end of the tubular solid oxide fuel cell to the back end of the tubular solid oxide fuel cell; and
varying independently a first electrical load applied by the first loading device to the first electrical circuit and a second electrical load applied by the second loading device to the second electrical circuit by controlling the first loading device and the second loading device with a microprocessor programmed to vary the first electrical load and the second electrical load independently, such that during operation of the tubular solid oxide fuel cell, the electrical potential across the front end of the tubular solid oxide fuel cell is different from the electrical potential across the back end of the tubular solid oxide fuel cell.