Patent Grant
11339968
The present disclosure relates to a lance of a burner, such as may be used to inject a liquid fuel or a gaseous fuel into a reheat burner of a sequential combustion gas turbine. The lance includes cooling microchannels and a tip having a shape generally resembling a prolate spheroid.
Some gas turbines used for electrical power generation include a sequential combustion system, in which combustion products from a first annular combustor pass through a first turbine section before being introduced into a second (reheat) annular combustor. In the second combustor, reheat burners introduce additional gaseous or liquid fuel into an annular combustion chamber, where it is ignited by the combustion products received from the first turbine section. The resulting combustion products are directed into a second turbine section, where they are used to drive the rotation of the turbine blades about a shaft coupled to a generator.
The fuel is introduced into the mixing chamber of the second combustor by lances configured for dual-fuel operation (that is, operating alternately on a gaseous fuel and on a liquid fuel). One example of such a lance is described in U.S. Pat. No. 8,943,831 to EROGLU et al. As shown in
The outlets 10 of the first injection passages 4 are axially shifted with respect to the outlets 11 of the second injection ports 7. The third injection passages 16 co-axially surround the outlet ends 10 of the first injection passages 4, and the fourth injection passages 17 co-axially surround the outlets 11 of the second injection passages 7. The third injection passages 16 are defined by holes in the wall of the third duct 15, thus defining a gap around the outlets 10 of each first injection passage 4.
Because the lance is disposed within the hot gas flow path of combustion products passing through the first combustor and the first turbine section, it is necessary to cool the lance to prevent damage and to extend service life. In the EROGLU patent, the air 18 passing through the third duct 15 is used to convectively cool the lance. However, such cooling air 18 must be at a sufficiently low temperature and a sufficiently high pressure to achieve the necessary cooling. Achieving the necessary pressure and temperature in the cooling air 18 may require the use of compressors (or booster compressors) and/or heat exchangers, which are parasitic loads that reduce undesirably the overall operational efficiency of the gas turbine.
Therefore, it would be useful to provide a lance for a secondary burner, which maintains the desired dual-fuel capability of the lance and which is configured to cool the lance using air at a lower pressure and/or a higher temperature, thereby improving turbine efficiency.
A lance for a burner includes an innermost conduit defining a first fluid passage and a plurality of first fuel injection channels, each first fuel injection channel terminating at a first outlet; an intermediate conduit circumferentially surrounding the innermost conduit, the intermediate conduit defining a second fluid passage and a plurality of second fuel injection channels, each second fuel injection channel terminating at a second outlet; an outermost conduit circumferentially surrounding the intermediate conduit, the outermost conduit defining a third fluid passage, a plurality of third air outlets through the outermost conduit and surrounding the first outlets, a plurality of fourth air outlets through the outermost conduit and surrounding the second outlets, and a plurality of cooling microchannels; wherein each cooling microchannel includes and extends between a microchannel inlet in fluid communication with the third fluid passage and a microchannel outlet on an outer surface of the outermost conduit.
The specification, directed to one of ordinary skill in the art, sets forth a full and enabling disclosure of the present system and method, including the best mode of using the same. The specification refers to the appended figures, in which:
Reference will now be made in detail to various embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the disclosure.
To clearly describe the present burner lance with dual fuel capability and microchannel cooling and the features thereof, certain terminology will be used to refer to and describe relevant machine components within the scope of this disclosure. To the extent possible, common industry terminology will be used and employed in a manner consistent with the accepted meaning of the terms. Unless otherwise stated, such terminology should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. Those of ordinary skill in the art will appreciate that often a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single part may include and be referenced in another context as consisting of multiple components. Alternatively, what may be described herein as including multiple components may be referred to elsewhere as a single integrated part.
In addition, several descriptive terms may be used regularly herein, as described below. The terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
As used herein, “downstream” and “upstream” are terms that indicate a direction relative to the flow of a fluid, such as the working fluid through the turbine engine. The term “downstream” corresponds to the direction of flow of the fluid, and the term “upstream” refers to the direction opposite to the flow (i.e., the direction from which the fluid flows. The term “inner” is used to describe components in proximity to the longitudinal axis or center of a component, while the term “outer” is used to describe components distal to the longitudinal axis or center of a component.
It is often required to describe parts that are at differing radial, axial and/or circumferential positions. As shown in
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Each example is provided by way of explanation, not limitation. In fact, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Although exemplary embodiments of the present disclosure will be described generally in the context of manufacturing turbine nozzles for a land-based power-generating gas turbine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present disclosure may be applied to other locations within a turbomachine and are not limited to turbine components for land-based power-generating gas turbines, unless specifically recited in the claims.
Referring now to the drawings,
Unlike conventional lances that have a cylindrical surface (as shown in
The interior of the tip portion 130 is shown in
An intermediate conduit 160 circumferentially surrounds the innermost conduit 150 and defines a passage 164 for the delivery of gaseous fuel 8 to the gaseous fuel injection channels 166 whose outlets are disposed at an approximately 90-degree angle (±10 degrees) relative to the axial centerline 131. The gaseous fuel injection channels 166 are generally frusto-conical in shape and, in the illustrated embodiment, are asymmetrical about an exit axis (represented by the arrow 8). The outlets 168 of the gaseous fuel injection channels 166 are larger in cross-sectional area than the outlets 158 of the liquid fuel injection channels 156. The outlets 168 are slightly inward of the surface 127 of the tip portion 130.
An outermost conduit 170 circumferentially surrounds the intermediate conduit 160 and defines the body 102 of the lance 100. The outermost conduit 170 defines a passage 174 for delivery of compressed cooling air 18 to a first set of air outlets 176 and a second set of air outlets 178, which provide for fluid communication through the lance tip 126 and into the combustion zone 25. As the compressed cooling air 18 is conveyed through the outermost conduit 170, the body 102 (including the downstream portion 120 and the tip portion 130) is convectively cooled.
The first set of air outlets 176 are disposed around the liquid fuel outlets 158 and help to cool the liquid fuel channels 156, thereby preventing coking. Additionally, the air outlets 176 may help to atomize the liquid fuel 5 as the liquid fuel 5 is injected. The second set of air outlets are disposed around the gaseous fuel outlets 168 and provide air 18 that mixes with the gaseous fuel 8 as the gaseous fuel 8 is introduced into the combustion zone 25. Such mixing helps to reduce emissions of nitrous oxides (NOx).
The concentric conduits 150, 160, 170 are shown in their entirety in
The unique geometry of the present lance 100 with its intricate pattern of microchannels, as will be discussed below, may be efficiently produced by an additive manufacturing process. In such case, the vertically oriented passage of the gaseous fuel conduit 160 may be provided with a stacked arrangement of ribs 165 to facilitate manufacturing.
The additive manufacturing process includes any manufacturing method for forming the lance 100 and its cooling features through sequentially and repeatedly depositing and joining material layers. Suitable manufacturing methods include, but are not limited to, the processes known to those of ordinary skill in the art as Direct Metal Laser Melting (DMLM), Direct Metal Laser Sintering (DMLS), Laser Engineered Net Shaping, Selective Laser Sintering (SLS), Selective Laser Melting (SLM), Electron Beam Melting (EBM), Fused Deposition Modeling (FDM), or a combination thereof.
In one embodiment, the additive manufacturing process includes the DMLM process. The DMLM process includes providing and depositing a metal alloy powder to form an initial powder layer having a preselected thickness and a preselected shape. A focused energy source (i.e., a laser or electron beam) is directed at the initial powder layer to melt the metal alloy powder and transform the initial powder layer to a portion of the lance 100 or one of its cooling features (e.g., microchannels 200).
Next, additional metal alloy powder is deposited sequentially in layers over the portion of the lance 100 to form additional layers having preselected thicknesses and shapes necessary to achieve the desired geometry. After depositing each additional layer of the metal alloy powder, the DMLM process includes melting the additional layer with the focused energy source to increase the combined thickness and form at least a portion of the lance 100. The steps of sequentially depositing the additional layer of the metal alloy powder and melting the additional layer may then be repeated to form the net or near-net shape lance 100.
While the majority of the air 18 flows through the outermost conduit 170 to be introduced through the tip portion 130 with the fuel (5 or 8) to convectively cool the body 102 and to mix with the fuel, a relatively small percentage of the air 18 is diverted into small air inlets (e.g., 202) of cooling microchannels (e.g., 200), as may be formed during the DMLM process described above. Air flowing through the microchannels produces a cooling film along the outer surface of the lance 100 in critical areas otherwise exposed to high temperatures due to exposure from the incoming hot combustion gases. By strategically placing the microchannels in these areas, the number of microchannels and the volume of cooling air may be advantageously reduced. Shorter microchannels (e.g., channels having a length of about 1 inch) may be used in higher temperature areas, while longer microchannels (e.g., channels having a length of about 2.5 to 3 inches) may be used in other areas.
A first set of these cooling microchannels 200 is disposed in the middle portion 140 of the lance 100 downstream of the balcony 106. As shown in
In many fuel lances having a cold fuel conduit disposed within a hotter outer conduit, the thermal discrepancy between the components can lead to wear that shortens the useful life of the lance. In the present lance 100, a self-centering fixation system 300 is disposed in the passage 174 between the outer surface of the intermediate conduit 160 and the inner surface of the outermost conduit 170. The fixation system 300, which is located along the longitudinal axis 101 of the lance 100, permits movement of the conduits 160, 170 along the longitudinal axis 131 of the downstream portion 120 and the tip portion 130. Movement along the radial direction of the downstream portion 120 (and, therefore, along the longitudinal axis 101 of the lance 100) is prevented.
The fixation system 300 includes hook-shaped elements 302, 304, 306, 308 and T-shaped pegs 310. The hook-shaped elements 302, 304, 306, 308 extend radially inward from the outermost conduit 170 and are arranged in pairs 302/304 and 306/308. The hook-shaped elements 302 and 304 are axially spaced from one another, and the hook-shaped elements 306 and 308 are axially spaced from one another. The hook-shaped elements 302 and 304 are circumferentially spaced from the hook-shaped elements 306 and 308, such that element 302 is opposite element 306 and element 304 is opposite element 308. The length of each T-shaped peg 310 spans the spacing of the hook-shaped elements 302, 304 and 306, 308.
Although the fixation system 300 is illustrated with four sets of hook-shaped elements 302-308 and T-shaped pegs 310, the number of sets may vary.
Exemplary embodiments of the present dual-fuel lance with cooling microchannels are described above in detail. The components described herein are not limited to the specific embodiments described herein, but rather, aspects of the methods and components may be utilized independently and separately from other components described herein. For example, the components described herein may have other applications not limited to practice with annular combustors for power-generating gas turbines, as described herein. Rather, the components described herein can be implemented and utilized in various other industries.
While the technical advancements have been described in terms of various specific embodiments, those skilled in the art will recognize that the technical advancements can be practiced with modification within the spirit and scope of the claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5181379 | Wakeman | Jan 1993 | A |
| 8281594 | Wiebe | Oct 2012 | B2 |
| 8572980 | Winkler | Nov 2013 | B2 |
| 8943831 | Eroglu | Feb 2015 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20200072469 A1 | Mar 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62724784 | Aug 2018 | US |
