Oxygen removal system

• US 7,735,670 B2
• Filed: 10/17/2006
• Issued: 06/15/2010
• Est. Priority Date: 10/17/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Michalakos, Peter M., Zaki, Rehan
• Primary Examiner(s): SWIATEK, ROBERT P
• Application Number:
  US11/550,066
• Publication Number:
  US 20080099618A1
• Time in Patent Office: 1,337 Days
• Field of Search: 244/135.R, 244/135.B, 220/88.3, 95/54, 261/DIG.2, 553/853, 961/55, 961/56
• US Class Current: 220/88.3
• CPC Class Codes: B01D 19/0073 by a method not covered by groups B01D19/0005 - B01D19/0042
• CPC Class Codes: B64D 37/32 Safety measures not otherwise provided for, e.g. preventing explosive conditions extinguishing or preventing fires in aircraft A62C
• CPC Class Codes: Y10S 261/02 Airplane

Abstract

A system and process to deplete or remove oxygen in the ullage of a fuel tank to reduce the oxygen/fuel vapor ratio below a lower explosion limit by exposing the ullage compounds to an oxygen removal catalyst active at a relatively low temperature. The oxygen removal catalyst may be a non-precious metal catalyst. A selective reaction of the oxygen by the catalyst forms primarily alcohols, aldehydes, and/or ketones and produces less than about 5% water by volume. The selective reaction, occurring at the relatively low temperature, reduces the risk of flammability of the fuel.

Claims

1. A method of removing oxygen from ullage of a fuel tank, comprising the steps of:

maintaining an oxygen removal catalyst at a temperature of less than a pre-determined temperature;

displacing fuel vapor and oxygen-rich air from the fuel tank to said oxygen removal catalyst to produce a vapor output comprising about 2% to about 5% by volume of water;

discharging the vapor output, from said oxygen removal catalyst to the fuel tank.

2. The method of claim 1, wherein said oxygen removal catalyst functions to maintain a higher percentage by volume of alcohols, aldehydes and ketones than of CO₂ in the reaction products at a temperature of less than 300°

F.

3. The method of claim 1, wherein the percentage of oxygen in the ullage is maintained at less than a pre-determined lower explosion limit, and said pre-determined temperature is less than about 300°

F.

4. The method of claim 1, wherein the percentage of oxygen in the ullage is maintained at 12% or less, and said pre-determined temperature is less than about 300°

F.

5. The method of claim 1, wherein the oxygen removal catalyst comprises a non-precious metal catalyst, and said pre-determined temperature is less than about 300°

F.

6. An oxygen removal system for a fuel tank, comprising:

an oxygen removal catalyst having a catalyst input connected to a fuel tank outlet, said oxygen removal catalyst having a catalyst output connected to a fuel tank input;

said oxygen removal catalyst being at a temperature below 200°

F. for selective consumption of oxygen so as to form reacted products in the form of vapor the majority of which are one or more of an alcohol, an aldehyde and a ketone or another oxygenated compound, wherein the vapor comprises about 2% to about 5% by volume of water; and

a pressurizing member disposed between said fuel tank outlet and said catalyst input, said pressurizing member capable of displacing vapor from an ullage region of the fuel tank into said oxygen removal catalyst, and out from said oxygen removal catalyst to said ullage region.

7. The oxygen removal system of claim 6, wherein the oxygen to fuel vapor ratio in the ullage is maintained at less than 12% oxygen.

8. The oxygen removal system of claim 6, wherein the vapor displacement operates in a continuous closed loop.

9. The oxygen removal system of claim 6, wherein the vapor displacement operates intermittently.

10. The oxygen removal system of claim 6, further comprising a pressurizing member for displacing the vapor at various rates dependent upon the oxygen percentage in the ullage region.

11. An oxygen removal system, comprising:

a fuel tank having an ullage region;

an oxygen removal catalyst for receiving fuel vapor and air from said ullage region;

said oxygen removal catalyst further being capable of a low temperature selective consumption of oxygen to produce oxygenated fuel and oxygen-poor air and about 2% to about 5% by volume of water;

said oxygen removal catalyst further for providing said oxygenated fuel and oxygen-poor air to said ullage region;

a blower for displacing said fuel vapor and air from said ullage region to said oxygen removal catalyst and for displacing said oxygenated fuel and oxygen-poor air from said oxygen removal catalyst to said ullage region; and

wherein the system does not have a water trap.

12. The oxygen removal system of claim 11, further comprising a heat exchanger operably connected with at least one of said fuel vapor or said oxygen poor air.

13. The oxygen removal system of claim 11, wherein said oxygen removal catalyst is active at a temperature below 200°

F.

14. The oxygen removal system of claim 11, wherein said oxygen removal catalyst is active at temperatures between about 72°

F. and about 200°

F.

15. The oxygen removal system of claim 11, wherein the oxygen removal catalyst comprises a non-precious metal.

16. The oxygen removal system of claim 11, further comprising at least one of a heat exchanger, a temperature sensor, a pressure gauge, and an oxygen sensor operably connected within said system.

17. The oxygen removal system of claim 11, wherein said oxygen removal catalyst comprises a packed bed.

18. The oxygen removal system of claim 11, wherein said oxygen removal catalyst comprises a washcoated monolith.

19. The oxygen removal system of claim 11, wherein said oxygen removal catalyst operates to form selective oxidation products from hydrocarbons.