Gradual oxidation and autoignition temperature controls

• US 9,273,608 B2
• Filed: 03/09/2012
• Issued: 03/01/2016
• Est. Priority Date: 03/09/2012
• Status: Active Grant

• Current Assignee: ReductoNox Corp.
• Original Assignee: Ener-Core Power, Inc. (Ener-Core, Inc.)
• Inventors: Maslov, Boris A.
• Primary Examiner(s): Sutherland, Steven
• Application Number:
  US13/417,125
• Publication Number:
  US 20130232982A1
• Time in Patent Office: 1,453 Days
• Field of Search: 607/74, 607/22, 607/23, 607/33, 607/77, 60/395, 60/392.81, 607/91, 60/391.82, 422/168, 422/173, 431/268, 431/2, 431/5, 431/7
• US Class Current: 1/1
• CPC Class Codes: F02C 3/22 the fuel or oxidant being gaseous at standard temperature and pressure F02C3/28 takes precedence
• CPC Class Codes: F02C 7/10 by means of regenerative heat-exchangers
• CPC Class Codes: F23C 2202/10 Premixing fluegas with fuel and combustion air
• CPC Class Codes: F23C 2900/99001 Cold flame combustion or flameless oxidation processes
• CPC Class Codes: F23C 9/08 for reducing temperature in combustion chamber, e.g. for protecting walls of combustion chamber
• CPC Class Codes: F23C 99/00 Subject-matter not provided for in other groups of this subclass
• CPC Class Codes: F23C 99/006 Flameless combustion stabilised within a bed of porous heat-resistant material F23C13/00 takes precedence; gas burners with radiant combustion on a porous surface F23D14/16
• CPC Class Codes: F23G 2206/203 with a power/heat generating installation
• CPC Class Codes: F23G 5/46 Recuperation of heat
• CPC Class Codes: F23G 7/065 using gaseous or liquid fuel
• CPC Class Codes: F23K 2900/05004 Mixing two or more fluid fuels
• CPC Class Codes: F23L 2900/07002 Injecting inert gas, other than steam or evaporated water, into the combustion chambers
• CPC Class Codes: F23M 2900/05004 Special materials for walls or lining
• CPC Class Codes: F23N 1/022 using electronic means
• CPC Class Codes: F23N 1/082 using electronic means
• CPC Class Codes: F23N 2225/16 burner temperature
• CPC Class Codes: F23N 5/003 using detectors sensitive to combustion gas properties F23N5/02, F23N5/18 - F23N5/26 take precedence
• CPC Class Codes: F23N 5/022 using electronic means F23N5/04 - F23N5/14 take precedence
• CPC Class Codes: F23R 2900/00002 Gas turbine combustors adapted for fuels having low heating value [LHV]
• CPC Class Codes: Y02E 20/12 Heat utilisation in combustion or incineration of waste
• CPC Class Codes: Y02E 20/34 : Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
• CPC Class Codes: Y02T 50/60 : Efficient propulsion technologies, e.g. for aircraft

Abstract

Described herein are embodiments of systems and methods for oxidizing gases. In some embodiments, a reaction chamber is configured to receive a fuel gas and maintain the gas at a temperature within the reaction chamber that is above an autoignition temperature of the gas. The reaction chamber may also be configured to maintain a reaction temperature within the reaction chamber below a flameout temperature. In some embodiments, heat and product gases from the oxidation process can be used, for example, to drive a turbine, reciprocating engine, and injected back into the reaction chamber.

Claims

1. A method for oxidizing fuel, comprising:

in an oxidation system that receives a gas comprising an oxidizable fuel into a reaction chamber having an inlet and an outlet and being configured to maintain an oxidation process, detecting when a temperature of the gas within the reaction chamber approaches or drops below a level such that the reaction chamber alone will not support oxidation of the fuel; and

changing, based on the temperature of the gas within the reaction chamber, at least one of (i) a residence time of the gas within the reaction chamber and (ii) an autoignition delay time within the reaction chamber sufficient for the gas to autoignite and oxidize while within the reaction chamber.

2. The method of claim 1, wherein the residence time of the gas is changed within the reaction chamber by altering flow of the gas through the reaction chamber.

3. The method of claim 2, wherein the residence time of the gas is changed within the reaction chamber by decreasing flow of the gas through the reaction chamber.

4. The method of claim 2, wherein the residence time of the gas is changed within the reaction chamber by recirculating flow of the gas from the outlet to the inlet of the reaction chamber.

5. The method of claim 1, wherein the changing comprises changing the autoignition delay time within the reaction chamber.

6. The method of claim 5, wherein the autoignition delay time is decreased within the reaction chamber by increasing the temperature of the gas within the reaction chamber with a heater.

7. The method of claim 5, wherein the autoignition delay time is decreased by circulating product gas from the outlet to the inlet.

8. The method of claim 1, wherein the reaction chamber maintains oxidation of the oxidizable fuel beneath a flameout temperature without a catalyst.

9. The method of claim 1, further comprising expanding product gas from the reaction chamber in a turbine or a piston engine.

10. The method of claim 1, further comprising compressing the gas prior to introducing the gas into the reaction chamber.

11. The method of claim 1, wherein the oxidizable fuel comprises at least one of hydrogen, methane, ethane, ethylene, natural gas, propane, propylene, propadiene, n-butane, iso-butane, butylene-1, butadiene, iso-pentane, n-pentane, acetylene, hexane, and carbon monoxide.

12. A method for oxidizing fuel, comprising:

in an oxidation system that receives a gas comprising an oxidizable fuel into a reaction chamber having an inlet and an outlet and being configured to maintain an oxidation process, detecting when a temperature of the gas within the reaction chamber approaches or drops below a level such that the reaction chamber alone will not support oxidation of the fuel; and

changing, based on the temperature of the gas within the reaction chamber, an autoignition delay time within the reaction chamber sufficient for the gas to autoignite and oxidize while within the reaction chamber.

13. The method of claim 12, wherein changing the autoignition delay time comprises introducing additional heat into the reaction chamber, thereby increasing an internal chamber temperature to a level that will maintain oxidation of the fuel.

14. The method of claim 12, further comprising changing the residence time of the gas within the reaction chamber by altering flow of the gas through the reaction chamber.

15. The method of claim 12, further comprising changing the residence time of the gas within the reaction chamber by decreasing flow of the gas through the reaction chamber.

16. The method of claim 12, further comprising changing the residence time of the gas within the reaction chamber by recirculating flow of the gas from the outlet to the inlet of the reaction chamber.

17. The method of claim 12, wherein the reaction chamber maintains oxidation of the oxidizable fuel beneath a flameout temperature without a catalyst.

18. The method of claim 12, further comprising expanding product gas from the reaction chamber in a turbine or a piston engine.

19. The method of claim 12, wherein the oxidizable fuel comprises at least one of hydrogen, methane, ethane, ethylene, natural gas, propane, propylene, propadiene, n-butane, iso-butane, butylene-1, butadiene, iso-pentane, n-pentane, acetylene, hexane, and carbon monoxide.

20. A method for oxidizing fuel, comprising:

receiving a gas comprising an oxidizable fuel into a reaction chamber;

determining a temperature of the gas within the reaction chamber;

when the temperature of the gas approaches or drops below a temperature level such that the reaction chamber alone will not support oxidation of the fuel, changing an autoignition delay time within the reaction chamber sufficient for the gas to autoignite and oxidize while within the reaction chamber and such that a flammability residence time of the gas within a flammability zone, defined as a volumetric fuel concentration between a lower flammability limit of the gas and an upper flammability limit of the gas, is less than the autoignition delay time.

21. The method of claim 20, wherein changing the autoignition delay time comprises decreasing the autoignition delay time.

22. The method of claim 20, further comprising changing a chamber residence time of the gas within the reaction chamber by altering flow of the gas through the reaction chamber.

23. The method of claim 20, further comprising changing the chamber residence time of the gas within the reaction chamber by decreasing flow of the gas through the reaction chamber.

24. The method of claim 20, further comprising changing the chamber residence time of the gas within the reaction chamber by recirculating flow of the gas from an outlet to an inlet of the reaction chamber.

25. The method of claim 20, wherein the reaction chamber maintains oxidation of the oxidizable fuel beneath a flameout temperature without a catalyst.

26. The method of claim 20, further comprising expanding product gas from the reaction chamber in a turbine or a piston engine.

27. The method of claim 20, wherein the oxidizable fuel comprises at least one of hydrogen, methane, ethane, ethylene, natural gas, propane, propylene, propadiene, n-butane, iso-butane, butylene-1, butadiene, iso-pentane, n-pentane, acetylene, hexane, and carbon monoxide.