ADVANCED CARBON DIOXIDE FUEL TANK INERTING SYSTEM

• US 20080128048A1
• Filed: 11/15/2006
• Published: 06/05/2008
• Est. Priority Date: 11/15/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: JOHNSON, RUSSELL W., ZAKI, REHAN, YATES, STEPHEN F.
• Granted Patent: US 7,905,259 B2
• Time in Patent Office: Days
• US Class Current: 141/59
• CPC Class Codes: B64D 37/32 Safety measures not otherwise provided for, e.g. preventing explosive conditions extinguishing or preventing fires in aircraft A62C

Abstract

An onboard inert gas generation system includes an evaporator comprising a vessel that receives a hydrocarbon fuel from a fuel tank, separates vapor fuel components from liquid fuel components, establishes a nearly constant fuel vapor composition, and outputs the fuel vapor to be mixed with air prior to combusting the fuel vapor and air mixture in a catalytic reactor. Water is separated from the inert gas produced and the inert gas is introduced into the ullage space of the fuel tank to prevent or reduce possible hazardous conditions in the fuel tank.

Claims

1. An onboard inert gas generation system comprising:

an evaporator, said evaporator comprising a vessel that receives a hydrocarbon fuel from a fuel line, separates vapor fuel components from liquid fuel components, establishes a nearly constant fuel vapor composition, and outputs a fuel vapor through a vapor line; and

a catalytic reactor that receives the fuel vapor and an air input containing oxygen as a component.

2. The system of claim 1, wherein said vessel drains said liquid fuel components through a fuel return line.

3. The system of claim 1, wherein less than 25% of the fuel is converted into vapor.

4. The system of claim 1, wherein said nearly constant fuel vapor composition varies by no more than plus or minus 20%.

5. The system of claim 1, further comprising:

a fuel heater that adds a controlled amount of heat to said fuel.

6. The system of claim 1, further comprising:

an air heater that adds a controlled amount of heat to air in an air input line; and

a mixing tee that receives the heated air and the fuel vapor and outputs a mixture of the heated air and the fuel vapor to a mixture line.

7. An aircraft fuel system comprising:

a fuel valve that meters fuel;

a fuel heater that heats the metered fuel from the fuel valve;

an evaporator that receives the metered, heated fuel and provides a fuel vapor having a nearly constant fuel vapor composition;

a mixing tee that mixes the fuel vapor with air; and

a catalytic reactor that reacts the fuel vapor and air mixture to produce an inert gas.

8. The system of claim 7, wherein the catalytic reactor operates at a sufficient temperature and space velocity to oxidize the fuel into carbon dioxide and water vapor at a conversion greater than 90% of the fuel vapor.

9. The system of claim 7, further comprising:

an air valve that meters air;

an air heater that heats the metered air fed from the air valve; and

a reactor inlet temperature indicator that provides a control signal to the air heater.

10. The system of claim 7, further comprising:

a reactor outlet temperature indicator that provides a control signal to the fuel heater.

11. The system of claim 7, further comprising:

an air valve that meters air;

an air heater that heats the metered air fed from the air valve;

a reactor inlet temperature indicator that provides a first control signal to the air heater;

a reactor outlet temperature indicator that provides a second control signal to the fuel heater and the fuel valve; and

a safety temperature indicator that provides a third control signal to the fuel valve.

12. The system of claim 7, further comprising:

an air valve that meters air;

a recuperative heat exchanger that heats the metered air fed from the air valve using heat from the catalytic reactor.

13. The system of claim 7, further comprising:

a water separator that receives a reactor output effluent from the catalytic reactor and removes condensed water from the reactor output effluent and delivers the inert gas.

14. A method for fuel tank inerting, comprising the steps of:

evaporating a fraction of fuel in a vessel into a fuel vapor;

combusting the fuel vapor with air in a reactor to form an inert gas; and

introducing the inert gas into an ullage space of the fuel tank.

15. The method of claim 14, further comprising:

metering a flow of liquid fuel in response to a control signal to control the fraction of fuel evaporated.

16. The method of claim 14, further comprising:

heating a flow of liquid fuel in response to a control signal to control the fraction of fuel evaporated.

17. The method of claim 14, further comprising:

heating an input air flow in response to a control signal before mixing the input air with the fuel vapor and feeding the fuel vapor with air to the reactor to control reactor operating conditions.

18. The method of claim 14, wherein:

the evaporating step uses only fuel from the fuel tank.

19. The method of claim 14, further comprising:

controlling the temperature of the inert gas using a safety temperature indicator.

20. The method of claim 14, wherein:

the reactor is loaded with an oxidation catalyst.