METHOD AND SYSTEM TO DETERMINE COMPOSITION OF FUEL ENTERING COMBUSTOR

• US 20090064682A1
• Filed: 09/06/2007
• Published: 03/12/2009
• Est. Priority Date: 09/06/2007
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Intile, John Charles, Frederick, Garth Curtis, Healy, Timothy Andrew, Citeno, Joseph Vincent
• Granted Patent: US 7,628,062 B2
• Time in Patent Office: Days
• US Class Current: 60/772
• CPC Class Codes: F02C 7/22 Fuel supply systems
• CPC Class Codes: F02C 9/40 specially adapted to the use of a special fuel or a plurality of fuels
• CPC Class Codes: F05D 2270/303 Temperature
• CPC Class Codes: F05D 2270/708 with comparison tables
• CPC Class Codes: F23N 2221/10 Analysing fuel properties, e.g. density, calorific
• CPC Class Codes: F23N 2241/20 Gas turbines
• 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: G01N 33/225 Gaseous fuels, e.g. natural gas

Abstract

Disclosed is a method and system for determining composition of a fuel entering a combustor. The method includes determining a temperature of the fuel entering the combustor, calculating a first estimated total fuel flow utilizing fuel properties and fuel nozzle effective area (A_e), and calculating a second estimated total fuel flow utilizing an aero-thermal cycle model analysis. The first estimated total fuel flow is compared to the second estimated total fuel flow and a lower heating value of the fuel is determined from a difference between the first estimated total fuel flow and the second estimated total fuel flow. A method and system for controlling a gas turbine includes calculating effects of the fuel composition on performance of the gas turbine and comparing one or more performance parameters to one or more parameter limits. One or more machine controls of the gas turbine are changed based on the results of the comparison.

Claims

1. A method for determining composition of a fuel entering a combustor comprising:

determining a temperature of the fuel entering the combustor;

calculating a first estimated total fuel flow utilizing fuel properties and fuel nozzle effective area (A_e);

calculating a second estimated total fuel flow utilizing an aero-thermal cycle model analysis;

comparing the first estimated total fuel flow to the second estimated total fuel flow; and

determining a lower heating value of the fuel from a difference between the first estimated total fuel flow and the second estimated total fuel flow.

2. The method of claim 1 including determining proportions of one or more constituents in the fuel.

3. The method of claim 2 wherein the proportions of one or more constituents are determined by inputting the lower heating value into a relative constituent model.

4. The method of claim 2 wherein the proportions of one or more constituents are determined by utilizing one or more constituent sensors to measure quantities of one or more constituents.

5. The method of claim 2 wherein the proportions of one or more constituents are determined by:

utilizing one or more constituent sensors to determine a quantity of at least one constituent of the one or more constituents;

inputting the quantity of the at least on constituent into a relative constituent model; and

determining the relative quantities of remaining desired constituents by inputting the lower heating value into the relative constituent model.

6. The method of claim 1 wherein the temperature of the fuel entering the combustor is determined by measuring the temperature of the fuel at an exit of at least one injector nozzle in the combustor.

7. A method for controlling a gas turbine comprising:

determining composition of a fuel entering the combustor of the gas turbine;

calculating effects of the fuel composition on performance of the gas turbine;

comparing one or more performance parameters to one or more parameter limits; and

changing one or more machine controls of the gas turbine based on the results of the comparison.

8. The method of claim 7 wherein the composition of a fuel is determined by:

determining a temperature of the fuel entering the combustor of the gas turbine;

calculating a first estimated total fuel flow utilizing fuel properties and fuel nozzle effective area (A_e);

calculating a second estimated total fuel flow utilizing an aero-thermal cycle model analysis;

comparing the first estimated total fuel flow to the second estimated total fuel flow; and

determining a lower heating value of the fuel from a difference between the first estimated total fuel flow and the second estimated total fuel flow.

9. The method of claim 8 including determining proportions of one or more constituents in the fuel.

10. The method of claim 9 wherein the proportions of one or more constituents are determined by inputting the lower heating value into a relative constituent model.

11. The method of claim 9 wherein the proportions of one or more constituents are determined by utilizing one or more constituent sensors to measure quantities of one or more constituents.

12. The method of claim 9 wherein the proportions of one or more constituents are determined by:

utilizing one or more constituent sensors to determine a quantity of at least one constituent of the one or more constituents;

inputting the quantity of the at least on constituent into a relative constituent model; and

determining the relative quantities of remaining desired constituents by inputting the lower heating value into the relative constituent model.

13. The method of claim 9 including calculating a flameholding margin by utilizing proportions of one or more constituents in the fuel.

14. The method of claim 13 including:

comparing the flameholding margin to a flameholding margin limit; and

changing one or more machine controls of the gas turbine based on the results of the comparison.

15. The method of claim 7 wherein the temperature of the fuel entering the combustor is determined by measuring the temperature of the fuel at an exit of at least one injector nozzle in the combustor.

16. A system for determining fuel composition entering a combustor including:

at least one temperature sensor capable of measuring a temperature of a fuel entering the combustor;

an engine model capable of outputting a first estimated total fuel flow based on a baseline fuel composition;

a fuel system model capable of outputting a second estimated total fuel flow based on the fuel temperature; and

a comparator capable of determining a lower heating value of the fuel by comparing the first estimated total fuel flow to the second estimated total fuel flow.

17. The system of claim 16 further comprising a relative constituent model capable of determining relative proportions of constituents in the fuel based on the lower heating value.

18. The system of claim 16 further comprising one or more constituent sensors to measure quantities of one or more constituents.