Aircraft fuel tank ullage gas management system

Patent metadata

Field	Value
Publication number	US-9623981-B2
Application number	US-201414552100-A
Country	US
Kind code	B2
Filing date	Nov 24, 2014
Priority date	Nov 24, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

An aircraft fuel tank ullage gas management system is disclosed. The system includes an electrochemical cell having a membrane electrode assembly that includes a cathode and anode separated by an electrolyte separator. A cathode fluid flow path is in fluid communication with the cathode, and receives the flow of cabin air from the cabin air fluid flow path and discharges nitrogen-enriched air. An anode fluid flow path is in fluid communication with the anode, and discharges oxygen or oxygen-enriched air. The electrochemical cell also includes water in fluid communication with the anode. The system includes an electrical power source and electrical connections to the anode and cathode for providing an electric potential difference between the anode and cathode. An ullage flow path receives nitrogen-enriched air from the cathode fluid flow path and delivers it to the fuel tank. An optional flow path delivers humidified oxygen-enriched air back to the cabin.

First claim

The invention claimed is:

1. An aircraft fuel tank ullage gas management system, comprising
a cabin air fluid flow path that receives a flow of aircraft cabin air;
an electrochemical cell comprising a membrane electrode assembly that comprises a cathode and an anode separated by an electrolyte separator, a cathode fluid flow path in fluid communication with the cathode that receives the flow of cabin air from the cabin air fluid flow path and discharges nitrogen-enriched air, an anode fluid flow path in fluid communication with the anode, water in fluid communication with the anode;
an electrical power source and electrical connections to the anode and cathode that provides power to an electrical circuit connecting the anode and cathode; and
an ullage flow path that receives nitrogen-enriched air from the cathode fluid flow path and delivers it to the fuel tank.

2. The system of claim 1 , further comprising a gas dryer disposed along the ullage flow path to dry the nitrogen-enriched air.

3. The system of claim 2 , wherein the gas dryer is a heat exchanger condenser having a heat rejection side in fluid communication with the nitrogen-enriched air, and a heat absorption side in fluid communication with ambient air.

4. The system of claim 3 , further comprising a condensate flow path that receives water condensed in the heat exchanger condenser and delivers it to the anode.

5. The system of claim 2 , wherein the gas dryer comprises a desiccant.

6. The system of claim 5 , further comprising a thermal flow path to transfer heat from electrochemical cell to the gas dryer for regeneration of the desiccant, or a dryer regeneration fluid flow path that receives a flow of aircraft cabin air.

7. The system of claim 1 , further comprising a cabin air return fluid flow path that receives an anode exhaust stream from the anode fluid flow path and discharges it to the cabin.

8. The system of claim 7 , further comprising a cabin air heat exchanger having a heat absorption side in fluid communication with the cabin air fluid flow path, and a heat rejection side in fluid communication with the cabin air return fluid flow path.

9. The system of claim 1 , that is configured to control electrical current and cabin air flow rate on the cabin air fluid flow path in response to a demand signal for nitrogen-enriched air.

10. The system of claim 1 , further comprising a water flow loop in fluid communication with the anode.

11. The system of claim 10 , further comprising a micro-porous plate adjacent to the anode, comprising micro-channels in fluid communication with the water flow loop.

12. The system of claim 1 , wherein the electrochemical cell is disposed in an electrochemical cell stack with one or more additional electrochemical cells comprising membrane electrode assemblies.

13. The system of claim 12 , further comprising a micro-porous bipolar plate disposed between each pair of adjacent electrochemical cells in the stack, comprising micro-channels in fluid communication with a water flow loop that is in fluid communication with the membrane electrode assemblies in the stack.

14. The system of claim 1 , wherein the electrolyte separator is a polymer electrolyte membrane.

15. The system of claim 1 , further comprising an auxiliary flow path that receives nitrogen-enriched air from the cathode fluid flow path and delivers it to a cargo bay, engine compartment, or other area of the aircraft to aid in fire suppression or provide an inerting atmosphere.

16. The system of claim 1 , wherein the electrical power source provides power to the circuit connecting the cathode and the anode at a voltage to hydrolyze water at the anode and form water at the cathode.

17. A method of operating the system of claim 1 , comprising
hydrolyzing water at the anode to form oxygen, hydrogen ions, and free electrons;
migrating the hydrogen ions across the electrolyte separator;
providing power from the electrical power source to the circuit to transport the free electrons through the circuit to the cathode; and
combining the free electrons, the hydrogen ions, and oxygen from the cabin air at the cathode to form water and the nitrogen enriched air.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Darling Robert Mason
• Perry Michael L

Classifications

• B64D37/32 Primary

  Safety measures not otherwise provided for, e.g. preventing explosive conditions · CPC title

• A62C3/065

  for containers filled with inflammable liquids · CPC title

• B01D2256/12

  Oxygen · CPC title

• C25B15/08

  Supplying or removing reactants or electrolytes; Regeneration of electrolytes · CPC title

• B01D2256/10

  Nitrogen · CPC title