US20160341429A1

Movatterモバイル変換

Info

Publication number: US20160341429A1
Application number: US14/717,570
Authority: US
Inventors: Kenneth Eugene Selfridge; Hua Zhang
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2015-05-20
Filing date: 2015-05-20
Publication date: 2016-11-24
Also published as: CN106168383A; EP3095987A1; JP2016217696A; EP3095987B1

Abstract

A method of supplying liquid fuel in a gas turbine engine is provided and includes sealing a fuel manifold with a fluid in the fuel manifold. The method also includes initiating routing of a liquid fuel from a liquid fuel supply structure to the fuel manifold. The method further includes displacing the fluid disposed in the fuel manifold with the liquid fuel. The method yet further includes routing the liquid fuel and the fluid into a combustor.

Description

BACKGROUND OF THE DISCLOSURE

The subject matter disclosed herein relates to gas turbine engines and, more particularly, to a liquid fuel supply system, as well as a method of supplying liquid fuel in a gas turbine engine.

During various operating conditions of a dual fuel gas turbine engine, it is required that liquid fuel is inhibited from entering a liquid fuel manifold. Examples of such operations include during gas fuel operation of the gas turbine engine or during a purge credit mode of the combustor assembly. This is done to protect the liquid fuel combustor nozzles and liquid fuel mixing valves. To block the liquid fuel from entering these locations, a valve assembly is employed upstream of these components and downstream of a liquid fuel supply.

A fluid may be routed to the liquid fuel manifold to pressurize the manifold when it is desirable to prevent liquid fuel from entering the fuel manifold or passing further downstream to the liquid fuel combustor nozzles. Upon initiation of a liquid fuel operation of the gas turbine engine, liquid fuel is to be routed to the combustor. Prior to doing so, the fluid disposed in the liquid fuel manifold must be removed to provide a clear path for the liquid fuel. Typically, this is done by completely draining the fluid from liquid fuel manifold and subsequently filling the manifold with liquid fuel. Unfortunately, the fluid draining procedure may account for a significant amount of time that is allotted for the transition to the liquid fuel operation, with the possibility of even exceeding the allotted time. Therefore, the delay associated with draining the fluid is an undesirable aspect for operators of gas turbine engines.

BRIEF DESCRIPTION OF THE DISCLOSURE

According to one aspect of the disclosure, a method of supplying liquid fuel in a gas turbine engine is provided and includes sealing a fuel manifold with a fluid in the fuel manifold. The method also includes initiating routing of a liquid fuel from a liquid fuel supply structure to the fuel manifold. The method further includes displacing the fluid disposed in the fuel manifold with the liquid fuel. The method yet further includes routing the liquid fuel and the fluid into a combustor.

According to another aspect of the disclosure, a method of supplying liquid fuel in a gas turbine engine is provided and includes sealing a fuel manifold with a water in the fuel manifold. The method also includes initiating routing of a liquid fuel from a liquid fuel supply structure to the fuel manifold. The method further includes displacing the water disposed in the fuel manifold with the liquid fuel, wherein displacing the water comprises routing the liquid fuel to the fuel manifold at varying flow rates. The method yet further includes routing the liquid fuel and the water into a combustor.

According to yet another aspect of the disclosure, a fuel supply system for a gas turbine engine includes a liquid fuel supply structure containing a liquid fuel. The fuel supply system also includes a combustor. The fuel supply system further includes a fuel manifold fluidly coupled to the liquid fuel supply structure to receive the liquid fuel and fluidly coupled to the combustor for selective distribution of the liquid fuel to the combustor. The fuel supply system yet further includes a liquid supply structure containing a liquid different from the liquid fuel, the liquid supply structure fluidly coupled to the fuel manifold for routing of the liquid to the fuel manifold, wherein the liquid fuel and the liquid are routed to the combustor upon initiation of routing the liquid fuel to the combustor.

These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the disclosure, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic illustration of a gas turbine engine;

FIG. 2 is a fuel supply system of the gas turbine engine in a first operating condition;

FIG. 3 is the fuel supply system in a second operating condition;

FIG. 4 is a plot of a first liquid fuel flow profile; and

FIG. 5 is a plot of a second liquid fuel flow profile.

The detailed description explains embodiments of the disclosure, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring toFIG. 1, a turbine system, such as agas turbine engine10, constructed in accordance with an exemplary embodiment of the present disclosure is schematically illustrated. Thegas turbine engine10 includes acompressor section12 and a plurality of combustor assemblies arranged in a can annular array, one of which is indicated at14. The combustor assembly is configured to receive fuel from afuel supply system20 through at least one fuel nozzle and a compressed air from thecompressor section12. The fuel and compressed air are passed into acombustor chamber18 defined by a combustor liner and ignited to form a high temperature, high pressure combustion product or air stream that is used to drive aturbine24. Theturbine24 includes a plurality of stages26-28 that are operationally connected to thecompressor12 through a compressor/turbine shaft30 (also referred to as a rotor).

In operation, air flows into thecompressor12 and is compressed into a high pressure gas. The high pressure gas is supplied to thecombustor assembly14 and mixed with fuel, for example natural gas, fuel oil, process gas and/or synthetic gas (syngas), in thecombustor chamber18. The fuel/air or combustible mixture ignites to form a high pressure, high temperature combustion gas stream, which is channeled to theturbine24 and converted from thermal energy to mechanical, rotational energy. As will be appreciated from the description herein, the fuel provided is a liquid fuel, but it is to be appreciated that embodiments of thegas turbine engine10 employ both liquid fuel and gas fuel, which may be employed during different operating conditions.

Referring now toFIGS. 2 and 3, thefuel supply system20 is illustrated in greater detail. Thefuel supply system20 includes a liquidfuel supply structure32 that stores and distributes liquid fuel. The liquidfuel supply structure32 is fluidly coupled to aliquid fuel manifold34 with a liquidfuel piping arrangement36. One ormore valves38 are included along the liquidfuel piping arrangement36 between the liquidfuel supply structure32 and theliquid fuel manifold34 to selectively transition between an open condition and a closed condition to control the flow rate of liquid fuel to theliquid fuel manifold34. Additionally, at least onevalve39 is included along the liquidfuel piping arrangement36 between theliquid fuel manifold34 and thecombustor chamber18 to selectively transition between an open condition and a closed condition to control the flow rate of the liquid fuel to thecombustor chamber18. As will be appreciated from the description herein, thevalve39 also controls the flow rate of a fluid that is disposed in theliquid fuel manifold34.

The

valves

38,39 are in the closed condition when thegas turbine engine10 is operating in a condition other than liquid fuel operation. For example, this may occur during gas fuel operation of thegas turbine engine10 or during a purge credit mode of thecombustor assembly14.

To reduce or eliminate the likelihood that liquid fuel undesirably leaks into or through theliquid fuel manifold34 during a closed condition of the

valves

38,39, pressurization of theliquid fuel manifold34 is provided with apurge system40. Thepurge system40 is fluidly coupled to thecombustor assembly14 and is configured to purge various portions of thecombustor assembly14 with a liquid, such as water, via a water manifold. More specifically, the water is demineralized water in certain embodiments. Thepurge system40 includes a fluid supply line42 (e.g., water supply line) that is fluidly coupled to a fluid supply44 (e.g., water supply) and theliquid fuel manifold34. Afluid valve52 is provided between thefluid supply44 and theliquid fuel manifold34 to control the flow rate of fluid to theliquid fuel manifold34. The fluid valve52 (e.g., water valve) transitions between an open state and a closed state to selectively control the flow rate of the fluid to theliquid fuel manifold34.

The fluid is pumped to theliquid fuel manifold34 to pressurize the components therein. Pressurization opposes any leaked portion of the liquid fuel that tends to pass through thevalve38, thereby reducing the likelihood of ingress of the liquid fuel to theliquid fuel manifold34 from upstream locations along the liquidfuel piping arrangement36. To effectively seal theliquid fuel manifold34 from the leaked portion of liquid fuel, the fluid pumped to theliquid fuel manifold34 must exceed the internal pressure of the liquidfuel piping arrangement36, which may vary depending upon the particular application and operating conditions.

InFIG. 2, thefuel supply system20 is illustrated in a first operating condition that defines a non-liquid fuel operation condition of thegas turbine engine10.FIG. 3 illustrates initiation of the liquid fuel operating condition, with the fluid being displaced from theliquid fuel manifold34 by the pressure of the oncoming liquid fuel.

During a gas turbine engine starting operation or transfer to a liquid fuel operation, the fluid disposed in theliquid fuel manifold34 must be removed to clear a path for the liquid fuel that is to be routed to thecombustor assembly14. Rather than wasting time with draining the fluid, the embodiments described herein simply employ the pressure of the liquid fuel to displace the fluid. This is done by opening the

valves

38,39. The liquid fuel and the fluid are then routed into thecombustor assembly14. Elimination or reduction of the draining process advantageously reduces the time required for initiation of a liquid fuel operation of thegas turbine engine10, whether during a fast start of thegas turbine engine10 or during a transition from gas fuel operation to liquid fuel operation. While it is contemplated that some of the fluid may be drained, typically all of the fluid is routed to thecombustor assembly14.

As described above, routing of the liquid fuel to theliquid fuel manifold34 comprises opening thevalve38. When done in conjunction with opening ofvalve39, the liquid fuel and the fluid are routed to thecombustor assembly14. Thevalve38 is configured to allow for control of the flow rate of the liquid fuel. In one embodiment, the flow rate is constant over the entire fluid removal process. However, in some embodiments it is advantageous to vary the flow rate of the liquid fuel during initiation of the liquid fuel operating condition. The advantages may be associated with the fuel supply profile required and/or with displacement characteristics of the fluid from theliquid fuel manifold34. For example,FIGS. 4 and 5 illustrate two exemplary liquid fuel flow rate profiles. In particular,FIG. 4 shows the liquid fuel being routed to theliquid fuel manifold34 in a stepped profile. Although only two distinct flow rates are illustrated, it is to be appreciated that more “steps” may be included in the flow profile. InFIG. 5, a constantly varying flow rate is illustrated. The specific flow rate profile of the liquid fuel during displacement of the fluid in the liquid fuel manifold will depend upon the particular application. Although illustrating an increasing flow rate over time, it is to be understood that the flow rate may decrease over time and that a combination of increasing and decreasing (e.g., pulsed flow) may be employed.

Advantageously, start or transition time for a liquid fuel operation is reduced by avoiding the need to completely drain the liquidfuel piping arrangement36, including theliquid fuel manifold34, of the fluid disposed therein during sealing of the arrangement. In some applications, operators of thegas turbine engine10 are sensitive to this response time to the degree of seconds. Therefore, even small amounts of reduced time periods are greatly desired by operators in some instances.

While the disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosure is not limited to such disclosed embodiments. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the disclosure. Additionally, while various embodiments of the disclosure have been described, it is to be understood that aspects of the disclosure may include only some of the described embodiments. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

What is claimed is:

1. A method of supplying liquid fuel in a gas turbine engine comprising:

sealing a fuel manifold with a fluid in the fuel manifold;

initiating routing of a liquid fuel from a liquid fuel supply structure to the fuel manifold;

displacing the fluid disposed in the fuel manifold with the liquid fuel; and

routing the liquid fuel and the fluid into a combustor.

2. The method ofclaim 1, wherein the fluid comprises water.

3. The method ofclaim 1, wherein the fluid comprises demineralized water.

4. The method ofclaim 1, wherein the initiating routing of the liquid fuel occurs during a transition from a gas fuel operation of the combustor to a liquid fuel operation of the combustor.

5. The method ofclaim 1, wherein the initiating routing of the liquid fuel occurs subsequent to a purging of the fuel manifold.

6. The method ofclaim 1, wherein all of the fluid in the fuel manifold is routed to the combustor.

7. The method ofclaim 1, wherein initiating routing of the liquid fuel comprises opening a first valve located between the liquid fuel supply structure and the fuel manifold.

8. The method ofclaim 1, wherein routing the liquid fuel and the fluid into the combustor comprises opening a second valve located between the fuel manifold and the combustor.

9. A method of supplying liquid fuel in a gas turbine engine comprising:

sealing a fuel manifold with a water in the fuel manifold;

displacing the water disposed in the fuel manifold with the liquid fuel, wherein displacing the water comprises routing the liquid fuel to the fuel manifold at varying flow rates; and

routing the liquid fuel and the water into a combustor.

10. The method ofclaim 9, wherein displacing the water with the liquid fuel comprises routing the liquid fuel to the fuel manifold at a first flow rate that is constant for a first period of time and a second flow rate that is constant for a second period of time.

11. The method ofclaim 9, wherein displacing the water with the liquid fuel comprises routing the liquid fuel to the fuel manifold at a constantly varying flow rate over a period of time.

12. The method ofclaim 9, wherein the initiating routing of the liquid fuel occurs during a transition from a gas fuel operation of the combustor to a liquid fuel operation of the combustor.

13. The method ofclaim 9, wherein the initiating routing of the liquid fuel occurs subsequent to a purging of the fuel manifold.

14. The method ofclaim 9, wherein all of the water in the fuel manifold is routed to the combustor.

15. A fuel supply system for a gas turbine engine comprising:

a liquid fuel supply structure containing a liquid fuel;

a combustor;

a fuel manifold fluidly coupled to the liquid fuel supply structure to receive the liquid fuel and fluidly coupled to the combustor for selective distribution of the liquid fuel to the combustor; and

a fluid supply structure containing a fluid different from the liquid fuel, the fluid supply structure fluidly coupled to the fuel manifold for routing of the fluid to the fuel manifold, wherein the liquid fuel and the fluid are routed to the combustor upon initiation of routing the liquid fuel to the combustor.

16. The fuel supply system ofclaim 15, wherein the fluid is water.

17. The fuel supply system ofclaim 15, wherein the fluid is demineralized water.

18. The fuel supply system ofclaim 15, wherein all of the fluid in the fuel manifold is routed to the combustor.