On board generation of n2 for fuel cells using a membrane
OwnerTony M.K. Thampan, Robert Beneschinventors
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Abstract
A PEMFC is operated in an operation mode in which a membrane-based humidifier is used to transfer moisture from a moisture-laden exhaust stream to the dry air feed and in a shutdown mode in which the membrane-based humidifier is used to permeate moisture and oxygen from the moisture-laden exhaust stream to provide a N2-rich exhaust for purging of the anode.
Claims15
An improved fuel cell system, comprising:
- a dry air feed;
- a source of compressed Hydrogen;
- a bypass conduit;
- a membrane-based humidifier having an evaporation side and a condensation side;
- a fuel cell having a cathode side, an anode side, and a moisture-laden exhaust outlet, said fuel cell being adapted to react air from said dry air feed and Hydrogen from said compressed Hydrogen source to produce electricity and produce a moisture-laden exhaust stream at said moisture-laden exhaust outlet, wherein said moisture-laden exhaust outlet is in fluid communication with said condensation side and said membrane-based humidifier is adapted to permeate some of the moisture in the moisture-laden exhaust stream from said condensation side to said evaporation side to produce a dried exhaust stream from said condensation side;
- a vent;
- a plurality of valves;
- and
- a controller adapted to actuate said plurality of valves in an operation mode and a startup/shutdown mode, wherein:
- in said operation mode, said controller actuates at least some of said plurality of valves to:
- place said dry air feed, said evaporation side, and said cathode side in fluid communication such that said dry feed is humidified by the moisture permeated from the moisture-laden exhaust stream and is fed to said cathode side;
- place said source of compressed Hydrogen and said anode side in fluid communication;
- place said condensation side and said vent in fluid communication such that the dried exhaust stream is vented;
- and
- in said startup/shutdown mode, said controller actuates at least some of said plurality of valves to:
- place said dry air feed, said bypass conduit, and said cathode side in fluid communication;
- isolate said evaporation side from said dry air feed;
- isolate said anode side from said source of compressed Hydrogen;
- place said condensation side and said evaporation side in fluid communication;
- direct a first portion of the dried exhaust stream from said condensation side to said evaporation side to sweep moisture therefrom and vent the moisture at said vent;
- and
- direct a second portion of the dried exhaust stream from said condensation side to said anode side.
A method of operating a fuel cell system comprising a dry air feed, a source of compressed Hydrogen, a bypass conduit, a membrane-based humidifier having an evaporation side and a condensation side, a fuel cell having a cathode side, an anode side, and a moisture-laden exhaust outlet, a vent, and a plurality of valves, said method comprising the steps of:
- directing the dry air feed to the evaporation side where the dry air feed is humidified to provide a humidified feed;
- directing the humidified feed to the cathode side;
- directing Hydrogen from the source of compressed Hydrogen to the anode side;
- reacting oxygen from the compressed humidified feed with the Hydrogen to produce electricity and a moisture-laden exhaust stream;
- directing the moisture-laden exhaust stream from the fuel cell to the condensation side where moisture permeates through the membrane of the humidifier to the evaporation side to provide the humidification of the dry air feed and to provide a dried exhaust stream;
- venting the dried exhaust stream.
Dependencies are inferred from the claim text.