Oxidizing fuel

• US 8,671,658 B2
• Filed: 03/18/2008
• Issued: 03/18/2014
• Est. Priority Date: 10/23/2007
• Status: Expired due to Fees

• Current Assignee: ReductoNox Corp.
• Original Assignee: Ener-Core Power, Inc. (Ener-Core, Inc.)
• Inventors: Prabhu, Edan
• Primary Examiner(s): Wongwian, Phutthiwat
• Assistant Examiner(s): SUTHERLAND, STEVEN M
• Application Number:
  US12/050,734
• Publication Number:
  US 20090100820A1
• Time in Patent Office: 2,191 Days
• Field of Search: 60/398.22, 607/23, 607/37, 607/76, 607/77, 60/395.3, 607/75, 60/392.6, 60/393, 60/395.5, 60/392.81
• US Class Current: 60/39.281
• CPC Class Codes: F02C 3/205 in a fluidised-bed combustor in combination with a steam cycle see F01K23/061; fluidised-bed apparatus in general B01J8/18; fluidised-bed combustors in general F23C10/00
• 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 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F23C 2900/99001 Cold flame combustion or flameless oxidation processes
• 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: F23R 3/26 Controlling the air flow
• CPC Class Codes: F23R 3/28 characterised by the fuel supply burners F23D
• 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

Abstract

A mixture of air and fuel is received into a reaction chamber of a gas turbine system. The fuel is oxidized in the reaction chamber, and a maximum temperature of the mixture in the reaction chamber is controlled to be substantially at or below an inlet temperature of a turbine of the gas turbine system. The oxidation of the fuel is initiated by raising the temperature of the mixture to or above an auto-ignition temperature of the fuel. In some cases, the reaction chamber may be provided without a fuel oxidation catalyst material.

Claims

1. A method of operating a gas turbine system, the method comprising:

receiving a mixture of air and fuel along a reaction chamber flow path in a reaction chamber of the gas turbine system;

igniting the fuel to raise the temperature of the mixture to or above an auto-ignition temperature of the fuel;

oxidizing the fuel while controlling a maximum temperature of the mixture in the reaction chamber to be between the auto-ignition temperature of the fuel and 1300°

C., wherein a fuel oxidation catalyst material is not used during the oxidation;

receiving a control flow comprising supplemental fuel through a plurality of ports located at a plurality of locations along the reaction chamber flow path in the reaction chamber, each of the plurality of ports being spaced from another of the plurality of ports along the flow path, each of the plurality of ports being connected to a supplemental fuel source for introduction of the supplemental fuel into the reaction chamber through the plurality of ports, and adjusting the control flow to control the maximum temperature of the mixture; and

detecting a characteristic comprising a temperature at one or more positions in the reaction chamber;

wherein adjusting the control flow comprises adjusting an amount of the control flow received into the reaction chamber based at least in part on the detected characteristic.

2. The method of claim 1, wherein the mixture of air and fuel is a substantially homogeneous mixture of air and one or more of oxidizable gas, oxidizable vapor, or oxidizable particles.

3. The method of claim 1, wherein the reaction chamber defines an air and fuel mixture flow path of sufficient duration that the flow rate of the air and fuel mixture along the flow path provides sufficient time for the fuel to oxidize substantially to completion.

4. The method of claim 1, further comprising heating the mixture before the mixture is received into the reaction chamber.

5. The method of claim 1, wherein the control flow further comprises air or a non-reactive fluid.

6. The method of claim 1, wherein the control flow comprises one or more of air or non-reactive fluid and adjusting the control flow comprises increasing an amount of the control flow received into the reaction chamber to decrease the maximum temperature of the mixture.

7. The method of claim 1, wherein the control flow further comprises air, and adjusting the control flow comprises adjusting an amount of the control flow received into the reaction chamber to increase a maximum temperature of the mixture.

8. The method of claim 1, wherein controlling a maximum temperature of the mixture in the reaction chamber comprises adjusting one or more of a flow rate of the mixture through the reaction chamber or a composition of the mixture in the reaction chamber.

9. The method of claim 1, wherein oxidizing the fuel comprises gradually oxidizing a majority of the fuel.

10. The method of claim 1, wherein controlling a maximum temperature of the mixture in the reaction chamber comprises controlling the maximum temperature to be substantially at or below an inlet temperature of a turbine of the gas turbine system.

11. The method of claim 1, wherein each of the plurality of ports is further connected to a non-reactive fluid source and an air source for introduction of a non-reactive fluid and air into the reaction chamber through the plurality of ports.

12. A method of operating a gas turbine system, the method comprising:

pressurizing a mixture of air and fuel along a reaction chamber flow path in a compressor of the gas turbine system;

initiating oxidation by raising the temperature of the mixture to or above an auto-ignition temperature of the fuel;

oxidizing the fuel in a reaction chamber of the gas turbine system while controlling a maximum temperature of the mixture in the reaction chamber to be between the auto-ignition temperature of the fuel and 1300°

C., wherein a fuel oxidation catalyst material is not used during the oxidation;

receiving a control flow comprising supplemental fuel through a plurality of ports located at a plurality of locations along the reaction chamber flow path in the reaction chamber, each of the plurality of ports being adjacent to another of the plurality of ports along the flow path, each of the plurality of ports being connected to a supplemental fuel source for introduction of the supplemental fuel into the reaction chamber through the plurality of ports, and adjusting the control flow to control the maximum temperature of the mixture;

detecting a characteristic comprising a temperature at one or more positions in the reaction chamber;

wherein adjusting the control flow comprises adjusting an amount of the control flow received into the reaction chamber based at least in part on the detected characteristic; and

expanding the oxidized mixture in a turbine of the gas turbine system.

13. The method of claim 12, wherein the pressurized mixture of air and fuel is substantially homogeneous.

14. The method of claim 13, the mixture comprising a fuel concentration below a sustainable-combustion threshold concentration.

15. The method of claim 12, wherein oxidizing the fuel comprises gradually oxidizing substantially all of the fuel.

16. The method of claim 12, wherein the fuel is oxidized in a flow path defined by the reaction chamber, a plurality of temperatures along the flow path defines a temperature gradient, and the temperature gradient generally increases from a flow path inlet temperature to a flow path outlet temperature.

17. The method of claim 12, further comprising controlling a maximum temperature of the mixture in the reaction chamber to be substantially at or below a turbine inlet temperature of the gas turbine system.

18. The method of claim 12, wherein the fuel is oxidized in a flow path defined by the reaction chamber, the method further comprising at least one of:

adjusting a flow rate of the mixture along the flow path;

adjusting a fuel concentration of the mixture;

receiving into the flow path one or more fuels to increase a temperature of the mixture;

receiving into the flow path air to decrease the temperature of the mixture;

receiving into the flow path air to decrease a rate of increase of the temperature of the mixture;

receiving into the flow path one or more non-reactive fluids to decrease a rate of increase of the temperature of the mixture;

or

receiving into the flow path one or more non-reactive fluids to decrease the temperature of the mixture.

19. The method of claim 12, further comprising heating the mixture before receiving the mixture into the reaction chamber.

20. The method of claim 12, wherein each of the plurality of ports is further connected to a non-reactive fluid source and an air source for introduction of a non-reactive fluid and air into the reaction chamber through the plurality of ports.

21. A gas turbine system comprising:

a compressor having an air and fuel mixture inlet and an outlet, the compressor adapted to compress the air and fuel mixture between the inlet and the outlet;

a reaction chamber in communication with the outlet of the compressor to receive the compressed air and fuel mixture along a reaction chamber flow path, the reaction chamber comprising an ignition source adapted to ignite the fuel and raise a temperature of the mixture above an auto-ignition temperature of the fuel, to oxidize at least a portion of the fuel, and to maintain a maximum temperature of the mixture in the reaction chamber between the auto-ignition temperature of the fuel and 1300°

C.;

a controller adapted to adjust a control flow comprising supplemental fuel received through a plurality of ports located at a plurality of locations along the reaction chamber flow path in the reaction chamber to control the maximum temperature of the mixture, each of the plurality of ports being adjacent to another of the plurality of ports along the flow path and each of the plurality of ports being connected to a supplemental fuel source for introduction of the supplemental fuel into the reaction chamber through the plurality of ports, and detect a characteristic comprising a temperature at one or more positions in the reaction chamber,

wherein adjusting the control flow comprises adjusting an amount of the control flow received into the reaction chamber based at least in part on the detected characteristic; and

a turbine inlet in communication with the reaction chamber, the turbine adapted to convert energy from the oxidized air and fuel mixture into rotational movement, and

the reaction chamber is provided without a fuel oxidation catalyst material.

22. The gas turbine system of claim 21, the reaction chamber comprising at least one of refractory material, rock, or ceramic.

23. The gas turbine system of claim 21, further comprising:

sensors to detect at least one of a temperature of the mixture or a flow rate of the mixture at one or more positions in the reaction chamber, wherein

the controller detects data from the sensors and controls at least one of a flow rate of the mixture or a temperature of the mixture in the reaction chamber.

24. The gas turbine system of claim 21, the reaction chamber defining an air and fuel mixture flow path of sufficient length that a flow rate of the air and fuel mixture along the flow path, averaged over the length of the flow path, allows the fuel to oxidize substantially to completion.

25. The gas turbine system of claim 21 further comprising a heat exchanger in communication with an inlet of the reaction chamber and the outlet of the compressor, the heat exchanger adapted to transfer heat energy from turbine exhaust gas to the mixture in the heat exchanger.

26. The gas turbine system of claim 25 further comprising a valve detecting an amount of turbine exhaust gas directed to the heat exchanger and controlling the amount of heat energy transferred from the turbine exhaust gas to the mixture in the heat exchanger.

27. The gas turbine system of claim 21, the reaction chamber comprising a reaction chamber inlet to receive the mixture into the reaction chamber, and a flame arrestor to reduce transfer of heat energy from the reaction chamber inlet to upstream of the reaction chamber inlet.

28. The gas turbine system of claim 21, the reaction chamber comprising a single reaction chamber.

29. The gas turbine system of claim 21, the turbine comprising a single turbine.

30. The gas turbine system of claim 21, the air and fuel mixture comprising a substantially homogeneous mixture of air and one or more of oxidizable gas, oxidizable vapor, or oxidizable particles.

31. The gas turbine system of claim 21, wherein maintaining the maximum temperature of the mixture in the reaction chamber comprises maintaining the maximum temperature substantially at or below a temperature of the turbine inlet.

32. The gas turbine system of claim 21, wherein each of the plurality of ports is further connected to a non-reactive fluid source and an air source for introduction of a non-reactive fluid and air into the reaction chamber through the plurality of ports.