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US 8,007,943 B2Granted
Cascaded stack with gas flow recycle in the first stage
AssigneeGM Global Technology Operations LLC
InventorRalf Senner
Life of this patent
Estimating the term…
Abstract
A fuel cell system including a humidification system is described. The humidification system employs a recycling system that recycles relatively humid gas exhausted from a multistage fuel cell stack, either on the anode and/or cathode side, and sends this relatively humid gas back to be combined with relatively dry supply gas, such as but not limited to hydrogen and/or air. The humidified supply gas mixture is then reintroduced into the first stage of the multistage fuel cell stack. A recirculation device, such as but not limited to a pump and/or an ejector, can be used to aid in moving the humid exhaust gas back through a recycle gas line to be combined with the supply gas.
Claims42
A fuel cell system, comprising:
- a first fuel cell stack having a fuel or oxidant gas inlet operable to receive an amount of fuel or oxidant gas and a fuel or oxidant exhaust gas outlet operable to exhaust an amount of fuel or oxidant exhaust gas;
- a second fuel cell stack having a fuel or oxidant gas inlet operable to receive the fuel or oxidant exhaust gas from the first fuel cell stack and a fuel or oxidant exhaust gas outlet operable to exhaust an amount of fuel or oxidant exhaust gas;
- and
- a gas recirculation system in fluid communication with the first and second fuel cell stacks, wherein the gas recirculation system includes a gas recirculation device that operates to increase the pressure of a recirculation gas;
- wherein the gas recirculation device is selected from the group consisting of a pump, ejector, compressor and combinations thereof;
- and
- wherein the gas recirculation system is operable to receive the fuel or oxidant exhaust gas from the fuel or oxidant exhaust gas outlet of the second fuel cell stack and reintroduce the fuel or oxidant exhaust gas into the fuel or oxidant gas inlet of the first fuel cell stack;
- wherein the fuel or oxidant exhaust gas and the fuel or oxidant gas are combined in the gas recirculation device prior to being reintroduced into the first fuel cell stack, said gas recirculation device being operable to increase the pressure of the exhaust gas that enters the gas recirculation system;
- wherein the exhaust gas has a higher moisture level than the fuel or oxidant gas.
6 more elements
A fuel cell system, comprising:
- a first fuel cell stack having a first fuel or oxidant gas inlet operable to receive an amount of fuel or oxidant gas and a first fuel or oxidant exhaust gas outlet operable to exhaust an amount of the fuel or oxidant exhaust gas;
- a second fuel cell stack having a second fuel or oxidant gas inlet operable to receive the fuel or oxidant exhaust gas from the first exhaust gas outlet of the first fuel cell stack, and a second fuel or oxidant exhaust gas outlet operable to exhaust a fuel or oxidant exhaust gas from the second fuel cell stack;
- a third fuel cell stack having a third fuel or oxidant gas inlet operable to receive the fuel or oxidant exhaust gas from the second exhaust gas outlet of the second fuel cell stack, and a third fuel or oxidant exhaust gas outlet operable to exhaust a fuel or oxidant exhaust gas from the third fuel cell stack;
- and
- a gas recirculation system receiving the fuel or oxidant exhaust gas from the third fuel or oxidant exhaust gas outlet of the third fuel cell stack and reintroducing the fuel or oxidant exhaust gas from the third fuel cell stack into the first fuel or oxidant gas inlet of the first fuel cell stack wherein the gas recirculation system includes a gas recirculation device that operates to increase the pressure of a recirculation gas;
- wherein the gas recirculation device is selected from the group consisting of a pump, ejector, compressor and combinations thereof;
- and
- wherein the exhaust gas of the first fuel cell stack and the fuel or oxidant gas are combined in the gas recirculation device prior to being reintroduced into the first fuel cell stack, said gas recirculation device being operable to increase the pressure of the exhaust gas that enters the gas recirculation system;
- wherein the exhaust gas has a higher moisture level than the fuel or oxidant gas.
6 more elements
A method of operating a fuel cell system, comprising:
- providing a first fuel cell stack having a fuel or oxidant gas inlet operable to receive an amount of fuel or oxidant gas and a fuel or oxidant exhaust gas outlet operable to exhaust an amount of fuel or oxidant exhaust gas;
- providing a second fuel cell stack having a fuel or oxidant gas inlet operable to receive the fuel or oxidant exhaust gas from the first fuel cell stack and a fuel or oxidant exhaust gas outlet operable to exhaust an amount of fuel or oxidant exhaust gas;
- and
- providing a gas recirculation system in fluid communication with the first and second fuel cell stacks;
- providing a gas recirculation device within the gas recirculation system that operates to increase the pressure of a recirculation gas;
- wherein the gas recirculation device is selected from the group consisting of a pump, ejector, compressor and combinations thereof;
- and
- wherein the gas recirculation system is operable to receive the fuel or oxidant exhaust gas from the fuel or oxidant exhaust gas outlet of the second fuel cell stack and reintroduce the fuel or oxidant exhaust gas into the fuel or oxidant gas inlet of the first fuel cell stack;
- wherein the fuel or oxidant exhaust gas and the fuel or oxidant gas are combined in the gas recirculation device prior to being reintroduced into the first fuel cell stack, said gas recirculation device being operable to increase the pressure of the exhaust gas that enters the gas recirculation system;
- wherein the exhaust gas has a higher moisture level than the fuel or oxidant gas.
7 more elements
A method of operating a fuel cell system, comprising:
- providing a first fuel cell stack having a first fuel or oxidant gas inlet operable to receive an amount of fuel or oxidant gas and a first fuel or oxidant exhaust gas outlet operable to exhaust an amount of the fuel or oxidant exhaust gas;
- providing a second fuel cell stack having a second fuel or oxidant gas inlet operable to receive the fuel or oxidant exhaust gas from the first exhaust gas outlet of the first fuel cell stack, and a second fuel or oxidant exhaust gas outlet operable to exhaust a fuel or oxidant exhaust gas from the second fuel cell stack;
- providing a third fuel cell stack having a third fuel or oxidant gas inlet operable to receive the fuel or oxidant exhaust gas from the second exhaust gas outlet of the second fuel cell stack, and a third fuel or oxidant exhaust gas outlet operable to exhaust a fuel or oxidant exhaust gas from the third fuel cell stack;
- and
- providing a gas recirculation system that receives the fuel or oxidant exhaust gas from the third fuel or oxidant exhaust gas outlet of the third fuel cell stack and reintroduces the fuel or oxidant exhaust gas from the third fuel cell stack into the first fuel or oxidant gas inlet of the first fuel cell stack;
- providing a gas recirculation device within the gas recirculation system that operates to increase the pressure of a recirculation gas;
- wherein the gas recirculation device is selected from the group consisting of a pump, ejector, compressor and combinations thereof;
- and
- wherein the exhaust gas and the fuel or oxidant gas are combined in the gas recirculation device prior to being reintroduced into the first fuel cell stack, said gas recirculation device being operable to increase the pressure of the exhaust gas;
- wherein the exhaust gas has a higher moisture level than the fuel or oxidant gas.
7 more elements
Dependencies are inferred from the claim text.