Method and apparatus to determine concentration of a fuel in a fuel mixture for a gas turbine engine

Abstract

Method and apparatus to determine a concentration of a fuel in a fuel mixture for a gas turbine engine are provided. A fuel mixture of the first fuel (e.g., natural gas) and a second fuel flow (e.g., hydrogen) flow through a pipeline including a density meter that supplies a signal indicative of density of the mixture. Based on the signal indicative of the density of the gaseous fuel mixture, temperature and pressure in connection with the gaseous fuel mixture, and certain known properties of the first fuel and the second fuel, a controller is configured to determining a respective concentration of at least one of the first fuel and the second fuel of the mixture. Disclosed embodiments permit determining the hydrogen concentration, for example, in the fuel mixture practically in real-time during operation of the engine and further permit providing a sufficiently fast update rate, which is advantageous to track and dynamically control changes that can occur in the composition of the fuel mixture practically in real-time.

Description

2024PF00865 - Subsequent FilingMETHOD AND APPARATUS TO DETERMINE CONCENTRATION OF A FUEL IN A FUEL MIXTURE FOR A GAS TURBINE ENGINEBACKGROUND

[0001] Disclosed embodiments are directed to method and apparatus for determining concentration of a fuel in a fuel mixture for a gas turbine engine, and, more particularly, to method and apparatus to determine such a concentration by way of a density meter.

[0002] Hydrogen is expected to play an important role in the future supply and storage of energy as the need to reduce greenhouse gas emissions further increases. This has sparked the interest in operating gas turbines on fuel mixtures involving various concentrations of hydrogen.

[0003] Reliable operation of a gas turbine engine involving a fuel mixture, such as including hydrogen mixed with a hydrocarbon-based fuel, e.g., natural gas, etc. requires finding the hydrogen concentration in the fuel mixture.

[0004] Certain known techniques for finding the hydrogen concentration in the fuel mixture tend to suffer from various drawbacks, such as inability to provide a sufficiently fast update rate when using gas chromatograph techniques, for example. Another known technique for finding the hydrogen concentration involves use of multiple sensing devices (e.g., flow meters) in each of the fuel lines conveying the fuel constituents of the fuel mixture and thus this can lead to undue complexity and incremental costs. At least in view of the foregoing considerations, further improvements are desired to reliably and cost-effectively find the hydrogen concentration in the fuel mixture in the context of a gas turbine engine, for example.BRIEF SUMMARY

[0005] In one aspect, disclosed embodiments provide apparatus to determine a concentration of a fuel in a fuel mixture for a gas turbine engine. The apparatus includes a mixing junction where a first gaseous fuel and a second gaseous fuel are mixed with one another to form a gaseous fuel mixture of the first gaseous fuel and the second gaseous fuel. A memory is configured to store data comprising respective predefined properties of the first gaseous fuel and the second gaseous fuel. The respective predefined properties of the first gaseous fuel and the second gaseous fuel comprise the respective molecular weights of the first gaseous fuel and2024PF00865 - Subsequent Filingthe second gaseous fuel. A pipeline is connected to the mixing junction to pass the gaseous fuel mixture. A density meter is disposed in the pipeline to supply a signal indicative of density of the gaseous fuel mixture. A controller is configured to receive the signal indicative of the density of the gaseous fuel mixture. The controller is further configured to read data comprising temperature and pressure in connection with the gaseous fuel mixture, and to read the data comprising the respective predefined properties of the first gaseous fuel and the second gaseous fuel. Based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective properties of the first gaseous fuel and the second gaseous fuel, the controller is configured to determine a respective concentration of at least one of the first gaseous fuel and the second gaseous fuel that form the gaseous fuel mixture.

[0006] In another aspect, disclosed embodiments provide a method to determine a concentration of a fuel in a fuel mixture for a gas turbine engine. The method includes the following actions: mixing at a mixing junction a first gaseous fuel and a second gaseous fuel to form a gaseous fuel mixture of the first gaseous fuel and the second gaseous fuel; storing in a memory data comprising respective predefined properties of the first gaseous fuel and the second gaseous fuel, the respective predefined properties of the first gaseous fuel and the second gaseous fuel comprising the respective molecular weights of the first gaseous fuel and the second gaseous fuel; connecting a pipeline to the mixing junction to pass the gaseous fuel mixture; disposing a density meter in the pipeline to supply a signal indicative of density of the gaseous fuel mixture; connecting a controller to receive the signal from the density meter the signal indicative of the density of the gaseous fuel mixture, where the controller is configured to read the data comprising temperature and pressure in connection with the gaseous fuel mixture, and to read the data comprising the respective properties of the first gaseous fuel and the second gaseous fuel; and, based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective properties of the first gaseous fuel and the second gaseous fuel, determining by way of the controller a respective concentration of at least one of the first gaseous fuel and the second gaseous fuel of the gaseous fuel mixture.2024PF00865 - Subsequent FilingBRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0007] FIG. 1 is a block diagram of one example embodiment of a disclosed apparatus to determine concentration of a fuel in a fuel mixture for a gas turbine engine.

[0008] FIG. 2 is a block diagram of another example embodiment of a disclosed apparatus.

[0009] FIG. 3 is a block diagram of yet another example embodiment of a disclosed apparatus.

[0010] FIG. 4 is a flow chart including one example analytical modality to determine a concentration of a fuel in a fuel mixture for a gas turbine engine.

[0011] FIG. 5 is a flow chart including an alternative example analytical modality to determine the concentration of the fuel in the fuel mixture.DETAILED DESCRIPTION

[0012] FIG. 1 is a block diagram of one example embodiment of a disclosed apparatus 10 to determine concentration of a fuel in a fuel mixture for a gas turbine engine 12. As would be appreciated by one skilled in the art, gas turbine engine 12 generally includes a compressor (not shown), one or more combustors 13 and a turbine 15 downstream of combustors 13. In one example embodiment, a mixing junction 14 permits mixing a first gaseous fuel 16 and a second gaseous fuel 18 with one another to form a gaseous fuel mixture of the first gaseous fuel and the second gaseous fuel. In one example embodiment, the first gaseous fuel 16 comprises a hydrocarbon-based fuel, such as natural gas, etc., and the second gaseous fuel 18 comprises hydrogen.

[0013] In one example embodiment, a memory (labeled M) 20 is configured to store data comprising respective predefined properties of the first gaseous fuel and the second gaseous fuel. In one example embodiment, the respective predefined properties of the first gaseous fuel and the second gaseous fuel comprise the respective molecular weights of the first gaseous fuel and the second gaseous fuel.

[0014] A pipeline 22 is connected to mixing junction 14 to pass the gaseous fuel mixture. A density meter (labeled D) 24 is disposed in pipeline 22 to supply a signal indicative of density of the gaseous fuel mixture. The signal from density meter 24 can be directly indicative of the density of the gaseous fuel mixture. Alternatively, the signal from density meter 24 can be2024PF00865 - Subsequent Filinginferentially indicative of the density of the gaseous fuel mixture, as would be the case, in embodiments where density meter 24 is based on a specific gravity sensor, for example. It will be appreciated that density meter 24 can be based on any of various modalities of operation, such as, without limitation, a Coriolis-based density meter, also referred to in the art as a mass flow meter or inertial flow meter; or can be an ultrasonic-based density meter.

[0015] A controller 30 is configured to receive the signal indicative of the density of the gaseous fuel mixture. Controller 30 is further configured to read data comprising temperature and pressure in connection with the gaseous fuel mixture, such as may be respectively obtained from a temperature sensor (labeled T) 32 and a pressure sensor (labeled P) 34. Controller 30 is also configured to read the data including the respective predefined properties of the first gaseous fuel and the second gaseous fuel, such as the respective molecular weights of the first gaseous fuel 16 and the second gaseous fuel 18.

[0016] Based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective properties of the first gaseous fuel and the second gaseous fuel, controller 30 is configured to determine a respective concentration of at least one of the first gaseous fuel and the second gaseous fuel that form the gaseous fuel mixture.

[0017] In one example embodiment, pipeline 22 is arranged to pass the gaseous fuel mixture to a fuel system skid 36 operatively connected during operation of the gas turbine engine, where density meter 24 is disposed in fuel system skid 36. As shown in FIG. 2, in an alternative embodiment, density meter 24' is disposed upstream of fuel system skid 32. That is, the density meter can be externally disposed relative to fuel system skid 36 or may be disposed in fuel system skid 36. In general, a "fuel system skid" for a gas turbine engine is a self-contained, portable package that conditions the fuel / s prior to delivery to the turbine engine with a goal of optimizing combustion within the turbine engine.

[0018] In yet another embodiment, as shown in FIG. 3, one density meter 24 is disposed in fuel system skid 36, and a second density meter 24' is disposed in the pipeline spaced apart from density meter 24 and located upstream of fuel system skid 36. This redundancy of density meters 24 and 24' provides an ability to detect certain operational issues that can arise in connection with the pipeline conveying the fuel mixture, such as presence of condensate, etc., which can result in large fluctuation or deviation in the respective density values determined by density meters 24 and 24'. That is, the redundancy of dual density meters is not per se in2024PF00865 - Subsequent Filingconnection with the determination of the concentration value of the H2 fuel but rather to enhance the reliability of such determination while providing an ability to detect certain operational issues that can arise in connection with the pipeline conveying the fuel mixture. For example, in a specific situation, when the mixture gas composition is fully known and expected to be constant, its density will also be a constant. In this case, if density meter shows variation in mixture density, it suggests that the mixture composition has been changed. An error between the expected corrected density and actual density indicates to the gas turbine controller that an unexpected fuel is being delivered, and the controller can be programmed or otherwise set to take an action like a warning and / or trip the engine based on the error value.

[0019] In one example embodiment, controller 30 is further configured to calibrate the measurement of the density of the gaseous fuel mixture relative to Standard Temperature and Pressure (STP) conditions.

[0020] In one example embodiment, the data comprising the respective predefined properties of the first gaseous fuel and the second gaseous fuel can further comprise respective Lower Heating Values (LHVs) of the first gaseous fuel and the second gaseous fuel. LHV of a fuel (or a fuel mixture) is also known in the art as net calorific value of the fuel (or the fuel mixture). The LHV of a fuel is measured in units of energy per unit of mass or volume.

[0021] In this example embodiment, based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective lower heating values (LHVs) of the first gaseous fuel and the second gaseous fuel, controller 32 can be further configured to, for example, determine a temperature-corrected Wobbe Index (WI) of the gaseous fuel mixture.

[0022] The following equation can be used to determine the temperature- corrected Wobbe Index (WI) of the gaseous fuel mixture:

[0025] Without being limited to any specific system of units, in the foregoing equation, LHV is in kJ / mA3; T is temperature of the fuel mixture in Kelvin; SG is the specific gravity (unitless ratio) of the fuel mixture. In this example, LHV, SG are calculated at standard conditions of 100 KPa and 288K. It is noted that to calculate SG at standard conditions, the determined density of the fuel mixture should be converted to STP conditions.2024PF00865 - Subsequent Filing

[0026] In one example embodiment, the signal indicative of the density of the gaseous fuel mixture comprises a sequence of signal updates indicative of the density of the gaseous fuel mixture, and the respective concentration determined by the controller comprises a sequence of data updates indicative of at least one of the concentrations of the first gaseous fuel and the second gaseous fuel. In one example embodiment, the sequence of data updates indicative of at least one of the concentrations of the first gaseous fuel and the second gaseous fuel has a data update rate in a range from 5 Hz to 100 Hz and preferably in a range from 10 Hz to 70 Hz. The foregoing update rate allows for determining transient changes that can occur in the composition of the fuel mixture at a relative high speed and is conducive to efficient dynamic accommodation of such transients by the control system of the gas turbine engine.

[0027] Moreover, in a practical implementation, changes that can occur in the composition of the fuel mixture involving hydrogen are more likely to occur due to H2 variation. Accordingly, having a quicker ability to determine occurrence of such changes in the fuel mixture reduces the level of risk in connection with operation of the gas turbine engine. By way of example, the foregoing update rate is conducive to a more responsive control loop between the respective valving equipment that controls the respective amounts of natural gas and hydrogen being delivered to the gas turbine engine and this can be used to quickly inhibit fuel composition fluctuations and can potentially reduce risk of flashback, for example.

[0028] FIG. 4 is a flow chart disclosing one example analytical modality to determine the concentration of given fuel (e.g., H2) in a fuel mixture for a gas turbine engine and includes example actions that can be performed for finding the hydrogen concentration in the fuel mixture in the context of a gas turbine engine.

[0029] As shown in block 402, this action allows obtaining by way of a density meter, a signal indicative of density of a fuel mixture comprising a first fuel (e.g., NG) and a second fuel (e.g., H2). As shown in block 404, this action allows reading temperature and pressure of the fuel mixture. As shown in block 406, this action allows reading respective predefined properties of the first gaseous fuel and the second gaseous fuel, such as by way of reading in memory 20 (FIG.1), the respective molecular weights of the first gaseous fuel and the second gaseous fuel. As shown in block 408, this action allows calibrating the signal indicative of the density of the fuel mixture relative to Standard Temperature and Pressure (STP), such as a temperature of 273 K and a pressure of 1 atmospheric pressure (atm), equivalent to 1.01325 bar or 101325 Pa.2024PF00865 - Subsequent Filing

[0030] As shown in block 410, this action allows for, based on the molecular weight of NG and H2, calculating the density of the mixture at STP. It will be appreciated that if the ambient conditions are at or relatively close to STP conditions, then there would not be a need to perform the actions described in the context of blocks 408 and 410. Accordingly, based on the actual ambient conditions, the foregoing actions can but need not be performed.

[0031] As shown in block 410, this action allows for, based on the respective MWs of NG and H2, and the mixture density at STP, calculating the Vol % of H2 based on the following equations:

[0032] The following allows determining Vol % of NG:

[0034] where x is indicative of Vol % of NG density and H2 density are determined at STP conditions before this step. The correction at STP is desirable since the pressure and temperature of fuel may be changing due to turbine operating condition and / or ambient conditions.

[0035] The following allows determining Vol % of H2:

[0036] Vol % of H2 = 100 - Vol % of NG.

[0037] FIG. 5 is a flow chart disclosing an alternative analytical modality to determine the concentration of given fuel (e.g., H2) in a fuel mixture for a gas turbine engine and includes example actions that can be performed for finding the hydrogen concentration in the fuel mixture in the context of a gas turbine engine.

[0038] As shown in block 502, this action allows obtaining by way of a density meter, a signal indicative of density of a fuel mixture comprising a first fuel (e.g., NG) and a second fuel (e.g., H2). As shown in block 504, this action allows reading temperature and pressure of the fuel mixture. As shown in block 506, this action allows reading respective predefined properties of the first gaseous fuel and the second gaseous fuel, such as by way of reading in memory 20 (FIG.1), the respective molecular weights of the first gaseous fuel and the second gaseous fuel.2024PF00865 - Subsequent Filing

[0039] As shown in block 508, this action allows for calculating the molecular weight of the mixture (MWmix), such as based on the ideal gas law. That is, R = P / pT, describing the well-established relationship between pressure (P (pascal), density (p (kg / mA3), temperature (T(Kelvin)), and where R represents the gas constant.

[0040]

[0041] The following equation allows calculating the molecular weight of the mixture (MWmix) as follows:

[0042]

[0044] As shown in block 510, this action allows calculating volume % of H2, such as may be based on a linear relationship between MWmix and the known molecular weight (MW) of the first fuel (e.g., NG) based on the following equation:

[0045]

[0046] H2 Vol% =constantconstant is the slope describing change in molecular weight from 0% hydrogen or natural gas to 100% hydrogen, where ,

[0048] where, MW of H2 and MW of NG are known or predetermined.

[0049] In operation, disclosed embodiments permit determining hydrogen concentration in the fuel mixture practically in real-time and further permit providing a sufficiently fast update rate for determining the hydrogen concentration, for example.

[0050] In operation, disclosed embodiments permit finding the hydrogen concentration without involvement of multiple sensing units and this results in a relatively straightforward and cost-effective implementation.

Claims

2024PF00865 - Subsequent FilingCLAIMSWhat is claimed is:

1. Apparatus to determine concentration of a fuel in a fuel mixture for a gas turbine engine, the apparatus comprising:a mixing junction where a first gaseous fuel and a second gaseous fuel are mixed with one another to form a gaseous fuel mixture of the first gaseous fuel and the second gaseous fuel;a memory configured to store data comprising respective predefined properties of the first gaseous fuel and the second gaseous fuel, the respective predefined properties of the first gaseous fuel and the second gaseous fuel comprising respective molecular weights of the first gaseous fuel and the second gaseous fuel;a pipeline connected to the mixing junction to pass the gaseous fuel mixture;a density meter disposed in the pipeline to supply a signal indicative of a density of the gaseous fuel mixture; anda controller configured to receive the signal indicative of the density of the gaseous fuel mixture, wherein the controller is further configured to read data comprising temperature and pressure in connection with the gaseous fuel mixture, and to read the data comprising the respective predefined properties of the first gaseous fuel and the second gaseous fuel, based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective properties of the first gaseous fuel and the second gaseous fuel, the controller configured to determine a respective concentration of at least one of the first gaseous fuel and the second gaseous fuel that form the gaseous fuel mixture.

2. The apparatus of claim 1, wherein the first gaseous fuel comprises a hydrocarbon-based fuel and the second gaseous fuel comprises hydrogen.

3. The apparatus of claim 2, wherein the hydrocarbon-based fuel is natural gas.

4. The apparatus of claim 1 or 3, wherein the pipeline is arranged to pass the gaseous fuel mixture to a fuel system skid operatively connected during operation of the gas turbine engine, wherein the density meter is disposed in the fuel system skid.2024PF00865 - Subsequent Filing5. The apparatus of claim 1 or 3, wherein the pipeline is arranged to pass the gaseous fuel mixture to a fuel system skid operatively connected during operation of the gas turbine engine, wherein the density meter is disposed upstream of the fuel system skid.

6. The apparatus of claim 1 , further comprising a second density meter disposed in the pipeline, the second density meter spaced apart from the density meter to supply a respective signal indicative of the density of the gaseous fuel mixture.

7. The apparatus of claim 6, wherein the pipeline is arranged to pass the gaseous fuel mixture to a fuel system skid connected to the gas turbine engine, wherein the density meter is disposed in the fuel system skid, and wherein the second density meter is disposed upstream of the fuel system skid.

8. The apparatus of any one of claims 1 to 5, wherein the controller is further configured to calibrate the measurement of the density of the gaseous fuel mixture relative to Standard Temperature and Pressure (STP) conditions.

9. The apparatus of any one of claims 1-5 or 8, wherein the data comprising the respective predefined properties of the first gaseous fuel and the second gaseous fuel further comprise respective Lower Heating Values (LHVs) of the first gaseous fuel and the second gaseous fuel.

10. The apparatus of claim 9, wherein, based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective lower heating values (LHVs) of the first gaseous fuel and the second gaseous fuel, the controller further configured to determine a temperature-corrected Wobbe Index (WI) of the gaseous fuel mixture.

11. The apparatus of any one of claims 1 or 9, wherein the signal indicative of the density of the gaseous fuel mixture comprises a sequence of signal updates indicative of the density of the gaseous fuel mixture, and wherein the respective concentration determined by the controller comprises a sequence of data updates indicative of at least one of the concentrations of the first gaseous fuel and the second gaseous fuel.

12. The apparatus of claim 11, wherein the sequence of data updates indicative of at least one of the concentrations of the first gaseous fuel and the second gaseous fuel have a a data update rate in a range from 5 Hz to 100 Hz.2024PF00865 - Subsequent Filing13. The apparatus of claim 1, wherein the signal from the density meter is directly or inferentially indicative of the density of the gaseous fuel mixture.

14. A method to determine concentration of a fuel in a fuel mixture for a gas turbine engine, the method comprising:mixing at a mixing junction a first gaseous fuel and a second gaseous fuel to form a gaseous fuel mixture of the first gaseous fuel and the second gaseous fuel;storing in a memory data comprising respective predefined properties of the first gaseous fuel and the second gaseous fuel, the respective predefined properties of the first gaseous fuel and the second gaseous fuel comprising respective molecular weights of the first gaseous fuel and the second gaseous fuel;connecting a pipeline to the mixing junction to pass the gaseous fuel mixture; disposing a density meter in the pipeline to supply a signal indicative of a density of the gaseous fuel mixture;connecting a controller to receive the signal from the density meter a measurement of the density of the gaseous fuel mixture, wherein the controller is configured to read the data comprising the temperature and pressure in connection with the gaseous fuel mixture, and to read the data comprising the respective properties of the first gaseous fuel and the second gaseous fuel,based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective properties of the first gaseous fuel and the second gaseous fuel, determining by way of the controller a respective concentration of at least one of the first gaseous fuel and the second gaseous fuel of the gaseous fuel mixture.

15. The method of claim 14, wherein the first gaseous fuel comprises a hydrocarbon-based fuel and the second gaseous fuel comprises hydrogen.

16. The method of claim 14, further comprising arranging the pipeline to pass the gaseous fuel mixture to a fuel system skid operatively connected during operation of the gas turbine engine, wherein the density meter is disposed in the fuel system skid.112024PF00865 - Subsequent Filing17. The method of claim 14, further comprising arranging the pipeline to pass the gaseous fuel mixture to a fuel system skid operatively connected during operation of the gas turbine engine, wherein the density meter is disposed upstream of the fuel system skid.

18. The method of claim 14, further comprising configuring the controller to calibrate the measurement of the density of the gaseous fuel mixture relative to Standard Temperature and Pressure (STP) conditions.

19. The method of claim 14, wherein the data comprising the respective predefined properties of the first gaseous fuel and the second gaseous fuel further comprise respective Lower Heating Values (LHVs) of the first gaseous fuel and the second gaseous fuel.

20. The method of claim 19, based on the signal indicative of the density of the gaseous fuel mixture, the temperature and pressure in connection with the gaseous fuel mixture, and the respective lower heating values (LHVs) of the first gaseous fuel and the second gaseous fuel, determining by way of the controller a temperature-corrected Wobbe Index (WI) of the gaseous fuel mixture.

21. The method of claim 20, wherein the signal indicative of the density of the gaseous fuel mixture comprises a sequence of signal updates indicative of the density of the gaseous fuel mixture, and wherein the respective concentration determined by the controller comprises a sequence of data updates indicative of at least one of the concentrations of the first gaseous fuel and the second gaseous fuel.

22. The method of claim 19, wherein the sequence of data updates indicative of at least one of the concentrations of the first gaseous fuel and the second gaseous fuel has a a data update rate in a range from 5 Hz to 100 Hz.12

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