Hydrogen recirculation without a pump
AssigneeGeneral Motors Corporation
InventorRobert Schafer
Life of this patent
Estimating the term…
Abstract
A fuel cell system that routes anode effluent from one fuel cell stack to the anode side of another fuel cell stack to consume unused hydrogen in the production of electricity is disclosed. The routing of the anode effluent from one fuel cell stack to another is accomplished by providing flow paths that connect the anode sides of the various fuel cell stacks together. The flow paths contain valves that are operable to selectively block flow through the various flow paths as desired. Optionally, the flow paths can be operated free of any valves. Methods of operating such fuel cell systems are also disclosed.
Claims16
A fuel cell system comprising:
- first and second fuel cell stacks each having an anode side with an inlet and an outlet and a cathode side with an inlet and an outlet, each fuel cell stack being operable to convert a hydrogen-containing anode reactant feed stream and an oxidant-containing cathode reactant feed stream into electricity, a hydrogen-containing anode effluent and an oxidant-containing cathode effluent;
- a first flow path connecting said anode outlet of said first fuel cell stack to said anode inlet of said second fuel cell stack;
- a second flow path connecting said anode outlet of said second fuel cell stack to said anode inlet of said first fuel cell stack;
- a first valve in said first flow path operable to modulate flow through said first flow path;
- a second valve in said second flow path operable to modulate flow through said second flow path;
- and
- a vent valve communicating with one of said first and second flow paths, said vent valve operable to modulate venting of anode effluent created by said first and second fuel cell stacks.
A method of operating a fuel cell system having first and second fuel cell stacks each operable to convert a hydrogen-containing anode reactant on an anode side of the fuel cell stack and an oxidant-containing cathode reactant on a cathode side of the fuel cell stack into electricity, a hydrogen-containing anode effluent on the anode side and an oxidant-containing cathode effluent on the cathode side, the method comprising:
- (a) operating the fuel cell system in a first mode including:
- (i) supplying an anode reactant to the anode side of the first fuel cell stack;
- (ii) routing an anode effluent from the first fuel cell stack to the anode side of the second fuel cell stack;
- and
- (iii) producing electricity with the first and second fuel cell stacks;
- (b) operating the fuel cell system in a second mode including:
- (i) supplying an anode reactant to the anode side of the second fuel cell stack;
- (ii) routing an anode effluent from the second fuel cell stack to the anode side of the first fuel cell stack;
- and
- (iii) producing electricity with the first and second fuel cell stacks;
- and
- (c) switching operation of the fuel cell system between said first and second modes.
Dependencies are inferred from the claim text.