SYSTEMS AND METHODS FOR LIQUID FUEL MODELING

• US 20140018973A1
• Filed: 07/13/2012
• Published: 01/16/2014
• Est. Priority Date: 07/13/2012
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Drohan, John Benjamin
• Granted Patent: US 9,149,776 B2
• Time in Patent Office: Days
• US Class Current: 700/300
• CPC Class Codes: B01F 35/20 Measuring; Control or regulation
• CPC Class Codes: B01F 35/21 Measuring
• CPC Class Codes: F02C 9/00 Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05
• CPC Class Codes: F02C 9/16 Control of working fluid flow F02C9/48 takes precedence; control of air-intake flow F02C7/057
• CPC Class Codes: F05D 2270/71 synthesized, i.e. parameter computed by a mathematical model
• CPC Class Codes: G05D 21/02 characterised by the use of electric means

Abstract

A system includes a model-based control unit configured to receive a lower heating value for a liquid fuel having a composition. The processor is configured to determine a specific gravity, a hydrocarbon ratio, or both, for the liquid fuel based, at least in part, on the lower heating value of the liquid fuel. The processor is configured to compare the hydrocarbon ratio, the specific gravity, and/or the lower heating value of the liquid fuel to a collection of hydrocarbon ratios, specific gravities, and/or lower heating values for a plurality of mixtures of methane and ethylene. The processor is configured to identify a mixture of methane and ethylene from the collection that best matches the hydrocarbon ratio, the specific gravity, and/or the lower heating value of the liquid fuel and configured to use the identified mixture of methane and ethylene as a model for the composition of the liquid fuel.

Claims

1. A system, comprising:

a model-based control unit comprising a processor configured to;

receive a lower heating value for a liquid fuel having a composition;

determine a specific gravity, a hydrocarbon ratio, or both, for the liquid fuel based, at least in part, on the lower heating value of the liquid fuel;

compare the hydrocarbon ratio, the specific gravity, and/or the lower heating value of the liquid fuel to a collection of hydrocarbon ratios, specific gravities, and/or lower heating values for a plurality of mixtures of methane and ethylene;

identify a mixture of methane and ethylene from the collection that best matches the hydrocarbon ratio, the specific gravity, and/or the lower heating value of the liquid fuel; and

use the identified mixture of methane and ethylene as a model for the composition of the liquid fuel.

2. The system of claim 1, comprising a gas turbine system configured to consume the liquid fuel.

3. The system of claim 2, wherein the model-based control unit is configured to model one or more parameters of the gas turbine system during operation using the model for the composition of the liquid fuel to obtain modeled parameters of the gas turbine system.

4. The system of claim 3, wherein the one or more parameters of the gas turbine system comprise exhaust temperature, exhaust composition, combustor temperature, fuel flow rates, air flow rates, or a combination thereof

5. The system of claim 3, wherein the model-based control unit is configured to alter the one or more parameters of the gas turbine system based, at least in part, on the modeled parameters of the gas turbine system.

6. The system of claim 1, wherein the collection comprises one or more tables of hydrocarbon ratios, specific gravities, and/or lower heating values for the plurality of mixtures of methane and ethylene.

7. The system of claim 1, wherein the collection comprises one or more graphs of hydrocarbon ratios, specific gravities, and/or lower heating values for the plurality of mixtures of methane and ethylene.

8. A method, comprising:

determining an estimated specific gravity of a liquid fuel based, at least in part, on a measured lower heating value of a liquid fuel having a composition;

determining an estimated hydrocarbon ratio of the liquid fuel based, at least in part, on the estimated specific gravity of the liquid fuel;

selecting a hydrocarbon mixture from a plurality of hydrocarbon mixtures to serve as a model for the composition of the liquid fuel, wherein the selected hydrocarbon mixture comprises a hydrocarbon ratio, a specific gravity, and/or a lower heating value similar to the estimated hydrocarbon ratio, the estimated specific gravity, and/or the measured lower heating value of the liquid fuel.

9. The method of claim 8, comprising using the model for the composition of the liquid fuel to determine one or more parameters of a gas turbine system, wherein the gas turbine system is configured to consume the liquid fuel.

10. The method of claim 8, comprising using the model for the composition of the liquid fuel to determine how to alter one or more parameters of a gas turbine system during operation.

11. The method of claim 10, wherein the one or more parameters of the gas turbine system comprise exhaust temperature, exhaust composition, power output, fuel flow rates, air flow rates, or a combination thereof

12. The method of claim 8, wherein the hydrocarbon mixture comprises a mixture of methane, ethylene, acetylene, ethane, propane, propylene, or a combination thereof

13. The method of claim 8, comprising determining the measured lower heating value of the liquid fuel using a calorimeter.

14. The method of claim 8, wherein the estimated specific gravity of the liquid fuel is determined using a graph, an equation, or a table that correlates specific gravities and lower heating values of liquid fuels.

15. The method of claim 8, wherein the estimated hydrocarbon ratio of the liquid fuel is determined using a graph, an equation, or a table that correlates hydrocarbon ratios and specific gravities of liquid fuels.

16. A non-transitory, computer-readable medium storing instructions executable by a processor of an electronic device, the instructions comprising instructions to:

determine a first lower heating value of a liquid fuel, wherein the liquid fuel comprises a composition, a first hydrocarbon ratio, and a first specific gravity;

identify a mixture of methane and ethylene having a second hydrocarbon ratio, second specific gravity, and/or second lower heating value that is similar to the first hydrocarbon ratio, the first specific gravity, and/or the first lower heating value to serve as a model of the composition of the liquid fuel when simulating a combustion system consuming the liquid fuel during operation; and

modify a parameter of the combustion system based, at least in part, on the simulation of the combustion system.

17. The medium of claim 16, comprising instructions to use the model of the composition of the liquid fuel to determine one or more exhaust conditions of the combustion system.

18. The medium of claim 16, wherein the parameter of the combustion system comprises an air flow rate, a fuel flow rate, or a combination thereof

19. The medium of claim 16, comprising instructions to determine the first specific gravity based, at least in part, on the first lower heating value, and instructions to determine the first hydrocarbon ratio based, at least in part, on the first specific gravity.

20. The medium of claim 16, comprising instructions to identify the mixture of methane and ethylene from one or more tables storing hydrocarbon ratios, specific gravities, and/or lower heating values for a plurality of mixtures of methane and ethylene.