Multiple stage combustion process to maintain a controllable reformation temperature profile
A reaction vessel that integrates and balances an endothermic process with at least one exothermic process of the fuel cell system. Preferably the exothermic process is conducted in stages to provide more uniform and/or controllable heat generation and exchange, and to produce a uniform and/or controllable temperature profile in the endothermic reaction process. The invention allows for the elimination of the working fluid loop of prior art systems that had unsatisfactory response times at startup, and during transient conditions, and also added to the overall mass and volume of the fuel cell system.
1. A system comprising:
a combination reaction vessel comprising:
a plurality of spaced apart endothermic reaction chambers, each of the plurality of endothermic reaction chambers having a flow path that extends from a flow path inlet to a flow path outlet and comprising an endothermic reaction catalyst to promote reformation of a reformation fuel supplied to the endothermic reaction chamber; and
a plurality of spaced apart exothermic reaction chambers, each of the plurality of exothermic reaction chambers having a flow path that extends from a flow path inlet to a flow path outlet and comprising an exothermic reaction catalyst to promote combustion of an exothermic reaction fuel with oxygen supplied to the exothermic reaction chamber;
wherein each of the exothermic reaction chambers is positioned between two endothermic reaction chambers and is defined in part by a wall that is shared with one or both of the endothermic reaction chambers so that heat generated from the combustion of the exothermic reaction fuel with oxygen in the exothermic reaction chamber is transferred through the wall to one or both of the endothermic reaction chambers, and wherein one of the exothermic reaction fuel or oxygen is introduced uniformly along the flow path of the exothermic reaction chamber so that a substantially uniform temperature profile is maintained along the flow path of the exothermic reaction chamber.
2. A system as set forth in claim 1 wherein the exothermic reaction catalyst overlies a face of the wall that faces the exothermic reaction chamber.
3. A system as set forth in claim 1 wherein the endothermic reaction catalyst overlies a face of the wall that faces the endothermic reaction chamber.
4. A system as set forth in claim 1 wherein a plurality of charge holes are provided and positioned along the flow path of each exothermic reaction chamber and wherein one of the exothermic reaction fuel or oxygen is charged into the exothermic reaction chamber utilizing the charge holes.
5. A system as set forth in claim 4 further comprising a charge manifold having a plurality of charge pipes extending therefrom and wherein each exothermic reaction chamber includes one of the charge pipes and wherein the charge holes are provided along a length of each charge pipe from the flow path inlet to the flow path outlet, and wherein the exothermic reaction fuel is charged through the charge holes.
6. A system as set forth in claim 4 wherein the exothermic reaction fuel comprises hydrogen and wherein the charge holes are positioned and configured in each exothermic reaction chamber so that a concentration of hydrogen and a temperature in each exothermic reaction chamber is such that flame combustion is prevented.
7. A system as set forth in claim 5 further comprising a valve associated with each charge pipe and further comprising a valve controller for selectively controlling the amount of exothermic reaction fuel charged to each exothermic reaction chamber.
8. A system as set forth in claim 7 further comprising sensors positioned in the exothermic reaction chambers to monitor the exothermic reaction therein, the sensors being operatively connected to the valve controller so that at least one of the exothermic reaction fuel or oxygen being charged to the exothermic reaction chambers can be selectively controlled.
9. A system as set forth in claim 5 wherein the plurality of exothermic reaction chambers are arranged in an adjacent side-by-side configuration, and wherein each charge pipe separates adjacent side-by-side exothermic reaction chambers.
10. A system as set forth in claim 5 wherein the plurality of exothermic reaction chambers are arranged in an adjacent side-by-side configuration, and further comprising a flow direction header at the end of each exothermic reaction chamber for directing gases exiting one exothermic reaction chamber to an entrance of the adjacent side-by-side exothermic reaction chamber.
11. A system as set forth in claim 6 wherein the combination reaction vessel includes an inlet opening communicating with the plurality exothermic reaction combustion chambers, and wherein the system further comprises a fuel cell stack having an anode exhaust line connected to the manifold to charge hydrogen through the manifold and a cathode exhaust line connected to the inlet opening of the combination reaction vessel to charge oxygen through the inlet opening.