CPOX reactor control system and method
A fuel reformer module ( 8005 ) for initiating catalytic partial oxidation (CPOX) to reform a hydrocarbon fuel oxidant mixture ( 2025, 3025 ) to output a syngas reformate ( 2027 ) to solid oxide fuel cell stack ( 2080, 5040 ). A solid non-porous ceramic catalyzing body ( 3030 ) includes a plurality of catalyst coated fuel passages ( 3085 ). A thermally conductive element ( 9005, 10005, 11005, 13005 ), with a coefficient of thermal conductivity of 50 W/m° K or greater is thermally conductively coupled with the catalyzing body. A first thermal sensor ( 8030 ) is thermally conductively coupled with the thermally conductive element. A second thermal sensor is thermally conductively coupled with a surface of the fuel cell stack. A control method independently modulates an oxidant input flow rate, based on first thermal sensor signal values, a hydrocarbon fuel input flow rate, based on second thermal sensor signal values.
1. A fuel reformer module for initiating catalytic partial oxidation (CPDX) to reform a hydrocarbon fuel oxidant mixture and deliver a syngas reformate therefrom comprising:
a catalyzing body, having an input end and an output end comprising a solid substrate formed to include a plurality of catalyst fuel passages extending therethrough;
a catalyst layer, comprising a material selected to initiate the CPDX reaction, formed onto an inside surface of each of the plurality of catalyst fuel passages;
a thermally conductive element, comprising a material having a coefficient of thermal conductivity of 50 W/m° K or greater, thermally coupled with the catalyzing body; and
a first thermal sensor, thermally coupled with the thermally conductive element, for generating a first temperature signal corresponding with a temperature sensed by the first thermal sensor,
wherein a contact area between the thermally conductive element and the catalyzing body is greater than a contact area between the first thermal sensor and the thermally conductive element.
2. The fuel reformer of claim 1 wherein the input end and the output end are separated by a first longitudinal dimension that extends along a longitudinal axis of the catalyzing body and the contact surface area between the thermally conductive element and the catalyzing body has a second longitudinal dimension that extends along the longitudinal axis of the catalyzing body, wherein the second longitudinal dimension is at least one quarter of the first longitudinal dimension.
3. The fuel reformer of claim 2 wherein the second longitudinal dimension is in a range of one quarter to one half of the first longitudinal dimension.
4. The fuel reformer of claim 2 wherein the second longitudinal dimension is in a range of one quarter of to equal to the first longitudinal dimension.
5. The fuel reformer of claim 1 wherein the catalyzing body is cylindrical with a first longitudinal dimension that extends a longitudinal axis of the catalyzing body between the input end and the output end.
6. The fuel reformer of claim 5 wherein the first longitudinal dimension is 25 mm or larger and an outside diameter dimension of the catalyzing body is 25 mm or larger.
7. The fuel reformer of claim 1 wherein the contact area between the thermally conductive element and body is sized to provide a heat flux density between the catalyzing body and the thermally conductive element that enables the first thermal sensor to sense a temperature change of 1 to 2 degrees centigrade in less than 30 seconds.
8. The fuel reformer of claim 1 wherein a material volume of the thermally conductive element is sized to provide heat flux between the catalyzing body and the thermally conductive element that enables the first thermal sensor to sense a temperature change of 1 to 2 degrees centigrade in less than 30 seconds.
9. The fuel reformer of claim 1 wherein the contact area between the thermally conductive element and the catalyzing body and a material volume of the thermally conductive element are sized to provide a heat flux density between the catalyzing body and the thermally conductive element that enables the first thermal sensor to sense a temperature change of 1 to 2 degrees centigrade in less than 30 seconds.
10. The fuel reformer of claim 1 wherein the input end and the output end are separated by a first longitudinal dimension that extends along a longitudinal axis of the catalyzing body and wherein each of the plurality of catalyst fuel passages extends, between the input end and the output end, along a fuel passage longitudinal axis that is parallel with the longitudinal axis of the catalyzing body.
11. The fuel reformer of claim 1 wherein solid substrate comprises an open cell foam material, and the plurality of catalyst fuel passages comprise a plurality of interconnecting open cells.
12. The fuel reformer of claim 5 wherein the thermally conductive element comprises a prismatic rod disposed in mating contact with the outside diameter of the catalyzing body and wherein a longitudinal axis of the prismatic rod is oriented substantially parallel with the longitudinal axis of the catalyzing body.
13. The fuel reformer of claim 11 wherein the catalyzing body is cylindrical about a longitudinal axis of the catalyzing body and the thermally conductive element comprises a prismatic rod disposed in mating contact with an outside diameter of the catalyzing body and wherein a longitudinal axis of the prismatic rod is oriented substantially parallel with the first longitudinal axis of the catalyzing body.
14. The fuel reformer of claim 5 wherein the thermally conductive element comprises a cylindrical segment disposed in mating contact with an outside diameter of the catalyzing body and wherein a longitudinal axis of the cylindrical segment is oriented substantially parallel with the longitudinal axis of the catalyzing body and wherein the cylindrical segment includes a contact surface area that is formed with a radius of curvature that is matched with a radius of curvature of an outside circumferential surface of the cylindrical catalyzing body.
15. The fuel reformer of claim 5 wherein the thermally conductive element comprises an annular wall encompassing a hollow cylinder having an inside diameter disposed in mating contact with the outside diameter of the catalyzing body, wherein a longitudinal axis of the annular wall is oriented substantially parallel with the longitudinal axis of the catalyzing body, and wherein the inside diameter is sized to substantially match the outside diameter of the catalyzing body.
16. The fuel reformer of claim 5 wherein the thermally conductive element comprises an annular wall encompassing a spiral portion of a hollow cylinder having an inside diameter disposed in mating contact with the outside diameter of the catalyzing body, wherein a longitudinal axis of the annular wall is oriented substantially parallel with the longitudinal axis of the catalyzing body, wherein the inside diameter is sized to substantially match the outside diameter of the catalyzing body.
17. The fuel reformer of claim 5 wherein the catalyzing body is formed to include a central cylindrical cavity, wherein the central cylindrical cavity is formed with a cavity inside diameter, wherein the thermally conductive element comprises a solid cylindrical element formed with a solid cylindrical element outside diameter, wherein the thermally conductive element is disposed inside the central cylindrical cavity, and wherein the cavity inside diameter is sized to substantially match the outside diameter of the solid cylindrical element.
18. An SOFC system comprising the fuel reformer module of claim 1 and further comprising:
a hydrocarbon fuel flow rate modulator and an air flow rate modulator configured to vary an oxygen to Carbon (O:C) ratio of a fuel air mixture being delivered to the input end;
an electronic controller operating to transmit independent command and control signals to each of the hydrocarbon fuel flow rate modulator and the oxidant flow rate modulator to vary the O:C ratio;
a solid oxide fuel cell (SOFC) stack comprising a plurality individual SOFC fuel cells each receiving the fuel air mixture for participating in an SOFC reaction;
a hot zone enclosure comprising a plurality of hot zone enclosure walls surrounding the SOFC stack;
a second thermal sensor, coupled to a surface of the hot zone enclosure walls for generating a second temperature signal corresponding with a temperature of the surface of the hot zone enclosure walls;
a range of first set point temperature values, stored by the electronic controller, corresponding with a range of desired first temperature signal values corresponding with the temperature of the thermally conductive element;
a range of second set point temperature values, stored by the electronic controller, corresponding with a range of second signal values corresponding with a temperature corresponding with a surface of the hot zone enclosure walls;
wherein the electronic controller operates a first control loop based on sampling the first thermal sensor signal values and controlling the oxidant flow rate modulator to increase or decrease the oxidant flow rate to maintain the sampled first temperature signal values within the range of first set point values; and,
wherein the electronic controller operates a second control loop based on sampling the second thermal sensor signal values and controlling the hydrocarbon fuel flow rate modulator to increase or decrease the hydrocarbon fuel flow rate to maintain the sampled second temperature signal values within the range of second set point values.
19. The fuel reforming module of claim 1 , further comprising a fuel reactor body comprising a reactor shield base wall, wherein the end of the fuel reactor body and the reactor shield base wall are opposing across an interface and wherein the reactor shield base wall is formed from a material having a coefficient of thermal conductivity of 140 W/m K or greater.