Combustion supply pipe with fuel passage

Abstract

The present invention relates to a burner supply pipe (01) and a burner assembly having the burner supply pipe (01). The burner supply pipe (01) has an extending pipe wall (05) with a pipe diameter (07) and at least one integrated fuel passage (11) extending from a fuel inlet (12) at an upstream pipe end (03) to a fuel outlet (13) at a downstream pipe end (04). In order to enable the integrated design, the fuel passage (11) is helical along most of the pipe length (06), and the gradient (14) of the fuel passage is at least 0.5 times and at most 5 times the pipe diameter (07).

Description

Technical Field

[0001] This invention relates to a burner supply pipe, which is part of a burner assembly, wherein fluid can be guided to the burner within the burner supply pipe. To further supply fuel, the burner supply pipe additionally includes an integrated fuel passage. Background Technology

[0002] A conventional burner assembly used in the combustion section of a gas turbine primarily comprises at least one burner. The burner itself is arranged upstream of the combustion chamber, where fuel and combustion air are co-combusted. For the present invention, the burner can be operated with two different types of fuel. Therefore, a burner assembly with two different fuel supply systems is required. Known solutions involve three coaxial tubes arranged upstream of the burner. A first fuel (typically gaseous fuel) is supplied to the burner through the center, and combustion air is supplied to the burner through an annular channel between the center tube and the intermediate tubes. The outer tube typically serves as a protective element for the upstream side of the burner assembly. Liquid fuel is typically used as the second fuel. Therefore, the cross-section for supplying liquid fuel can be significantly smaller than that required for supplying gaseous fuel. Thus, a common solution includes fuel conduits arranged parallel to the tube assembly to guide the liquid fuel to the burner.

[0003] Even though using fuel lines is a common and readily available solution, some problems remain because thermal displacement and burner assembly sealing need to be considered. Therefore, a further solution attempts to integrate the fuel passage into one of the pipes as a straight hole within the pipe wall. To prevent an increase in the thickness of the corresponding pipe, several holes with smaller diameters are typically used instead of a single pipe arranged outside the main pipe. Summary of the Invention

[0004] The objective of this invention is to design an improved scheme for supplying liquid fuel to a burner in parallel with an assembly of coaxial tubes for gaseous fuel and combustion air.

[0005] This task is solved by the burner supply pipe according to claim 1. A burner assembly having such a burner supply pipe is given in claim 7. Further advantageous solutions are the subject of the dependent claims.

[0006] A typical burner supply pipe first comprises a pipe wall extending from an upstream pipe end to a downstream pipe end, and has a substantially cylindrical shape. Therefore, the burner supply pipe defines a pipe length from the upstream pipe end to the downstream pipe end and a pipe diameter as the outer dimension of the pipe wall. Here, the pipe length is at least twice and at most 20 times the pipe diameter. Furthermore, the burner supply pipe is a hollow component with a relatively thin wall, wherein the wall thickness is at least 0.01 times and at most 0.2 times the pipe diameter.

[0007] To enable the supply of liquid fuel along the burner supply pipe, the burner supply pipe also includes at least one integrated fuel passage extending along the pipe wall. Necessarily, the fuel passage begins at a fuel inlet and leads to a fuel outlet. Here, the fuel inlet is not necessarily located directly at the upstream pipe end, but needs to be located at least in the edge region near the upstream pipe end. Similarly, the fuel outlet is located at the downstream pipe end, either in the edge region of the downstream pipe end or directly at the downstream pipe end.

[0008] It must be noted that the burner supply pipe does not necessarily have a free upstream pipe end and / or a free downstream pipe end. As part of the burner assembly, additional components will be arranged at the upstream and / or downstream pipe ends of the burner supply pipe. To determine the burner supply pipe having the upstream and downstream pipe ends in the sense of this invention, the pipe wall, fuel inlet, and fuel outlet need to be considered. If the upstream or downstream pipe end cannot be clearly determined by the shape of the pipe wall, which includes a fuel inlet near the upstream pipe end and a fuel outlet near the downstream pipe end, then the upstream pipe end is 0.25 times the pipe diameter upstream of the fuel inlet, and similarly, the downstream pipe end is 0.25 times the pipe diameter downstream of the fuel outlet.

[0009] The system should be able to supply fuel, particularly liquid fuel, to the burner through the fuel passage. Therefore, the equivalent diameter of the fuel passage should not be less than 0.3 times the wall thickness.

[0010] Obviously, if the fuel passage is circular, then the diameter of that circle is the equivalent diameter of the fuel passage. Otherwise, the equivalent diameter can be calculated by determining the cross-section of the fuel passage.

[0011] To accommodate the fuel passage integrated into the burner supply pipe, the size of the fuel passage should not exceed certain limits. (Obviously, in the prior art where fuel passages are integrated within the pipe wall, the diameter of the fuel passage must be smaller than the thickness of the pipe wall.) Here, in order to accommodate the fuel passage at the burner supply pipe, the equivalent diameter of the fuel passage should not exceed three times the wall thickness of the pipe wall.

[0012] To increase the diameter of the fuel passage and prevent uncontrolled deformation of the burner supply pipe due to thermal displacement, the fuel passage is now designed as a spiral component. The fuel passage does not necessarily have to include a spiral shape from the fuel inlet to the fuel outlet, but at least along a significant portion of the pipe length, the fuel passage needs to have a spiral design with a gradient of at least 0.5 times and at most 5 times the pipe diameter.

[0013] To ensure sufficient stability of the burner supply pipe at the location of the fuel passage, it is advantageous to increase the thickness of the pipe wall in that specific region. Therefore, it is advantageous to locally thicken the pipe wall at the location of the fuel passage, both on the outer side and / or the inner side.

[0014] The primary benefit is that the size of the fuel passage can be increased because thickening is allowed on the outside and / or inside of the burner supply pipe due to the fuel passage. Even with this thickening, the thermal stress on the component, due to the helical shape, will not lead to uncertain deformation or unacceptable thermal stress within the pipe wall. This is typically a major issue if the fuel passage has a large size and lies in a straight line along the pipe wall, and different thermal expansion occurs within the pipe wall at and beside the fuel passage. Next, the thickening of the pipe wall due to the fuel passage will positively affect the fluid flow inside and / or outside the burner supply pipe by adding eddies to the fluid flow.

[0015] However, the thickness should not exceed what is necessary. Therefore, the local thickness of the burner supply pipe at the fuel passage is advantageously up to three times the equivalent diameter of the fuel passage.

[0016] Similarly, the local thickness of the burner supply pipe at the fuel passage is advantageously up to three times the wall thickness of the pipe.

[0017] The solution of the present invention yields the greatest benefit if the burner supply pipe comprises certain relative dimensions. Therefore, it is advantageous that the pipe length is at least 4 times and / or at most 10 times the pipe diameter. It is also advantageous that the wall thickness is at least 0.02 times and / or at most 0.1 times the pipe diameter. Thus, the pipe wall has a pipe shape in the conventional sense.

[0018] To arrange the fuel passages in a spiral shape at the pipe wall and to utilize the optimal dimensions of the fuel passages, it is particularly advantageous to arrange only one fuel passage or only two fuel passages arranged opposite each other at the burner supply pipe. It may still be advantageous to utilize three fuel passages arranged offset in the circumferential direction. However, with each additional passage, the benefits of the solution of the present invention decrease as it approaches known solutions.

[0019] Next, if the equivalent diameter of the fuel passage is advantageously at least 0.6 times the wall thickness, a beneficial liquid fuel supply can be achieved using a burner supply pipe. This—not necessarily but usually—results in a thickening of the outer and / or inner sides of the pipe wall. As explained earlier, a spiral-shaped thickening does not impede the practicality of the solution, but increasing the size of the fuel passage can improve the supply of liquid fuel through a single (each or one) fuel passage.

[0020] On the other hand, the size of the fuel passage should not be too large compared to the thickness of the pipe wall. It is advantageous here that the equivalent diameter is at most 1.5 times the wall thickness.

[0021] To prevent unacceptable thermal stress within the burner supply pipe and to prevent uncontrollable thermal deformation, it is further advantageous that the spiral section of the fuel passage has a specific shape relative to the dimensions of the burner supply pipe. Advantageously, the gradient of the fuel passage is at least one and / or at most 2.5 times the pipe diameter. Within this range, optimal results can be obtained for thermal stress.

[0022] Clearly, arranging the fuel inlet or fuel outlet on the inside of the pipe wall is less meaningful, as connecting to the next component upstream (fuel inlet) or downstream (fuel outlet) is more difficult. Therefore, it is possible to arrange a fuel inlet with an opening to the upstream side at the upstream pipe end and a fuel outlet with an opening to the downstream side at the downstream pipe end. However, it is preferable to arrange the fuel inlet and / or fuel outlet on the outside of the burner supply pipe wall. This simplifies the connections to the fuel inlet and fuel outlet, respectively, if the attached components surround the upstream and downstream pipe ends of the burner supply pipe, respectively.

[0023] The fuel passage is an integrated feature of the burner supply pipe and therefore needs to be located on or inside the pipe wall. Even if the fuel passage can be located on the outside or inside of the pipe wall, it is advantageous to at least locate the center of the fuel passage on the outside or inside of the pipe wall (where there is no fuel passage). It is particularly advantageous to locate the center of the fuel passage between the middle and the inside of the pipe wall.

[0024] The burner supply pipe of this invention enables the design of novel, inventive burner assemblies intentionally used in the combustion section. In principle, the burner assembly can be used in different types of combustion systems, but it is advantageously used in the combustion section of a gas turbine. The burner assembly first comprises a burner intentionally arranged upstream of the combustion chamber in the combustion section. A common solution for supplying different types of fuel and combustion air to the burner includes a pipe assembly arranged upstream of the burner. This pipe assembly includes an outer protective pipe located outside the pipe assembly. Next, a burner supply pipe is required within the outer protective pipe. A first internal fluid supply pipe is arranged within the burner supply pipe. Therefore, an external annular space is arranged between the outer protective pipe and the burner supply pipe. A second annular space can be obtained inside the burner supply pipe, between it and the first internal supply pipe.

[0025] In another advantageous solution, the pipe assembly includes a second internal fluid supply pipe disposed within the first internal fluid supply pipe, thereby forming an additional annular space between the two internal fluid supply pipes.

[0026] Which annulus to use to guide fuel, especially gaseous fuel, and which annulus to use to guide combustion air, is irrelevant to the topic of this article.

[0027] The burner assembly of the present invention provides an improved feasible solution for supplying liquid fuel to the burner, which utilizes the burner supply pipe of the present invention and advantageously guides the liquid fuel through the fuel passage within the burner supply pipe from the upstream side of the pipe assembly to the downstream side of the burner.

[0028] First, how the tube assembly and burner are connected is irrelevant to the content discussed in this article. One feasible approach is to fit the downstream ends of one or more tubes into corresponding sleeves in the burner. To ensure the safe routing of fuel and combustion air to the separate burners, and to allow the tube assembly to be held in a fixed position relative to the burner, it is advantageous to securely connect the external protective tube to the burner.

[0029] Here, the external protective tube can be installed at the burner. Another option is a solution that welds or brazes the two components together. A third option is an integrated solution.

[0030] The burner supply pipe can also be arranged movably within the burner sleeve. However, it is advantageous to securely connect the burner supply pipe to the burner. This also applies to the first fluid supply pipe and, if a second fluid supply pipe exists, to it. It is particularly advantageous that all pipes of the pipe assembly are securely connected to the burner.

[0031] To enable the fitting of additional pipes and channels to the pipe assembly, the burner assembly advantageously includes an end-connection block. This end-connection block is positioned upstream of the pipe assembly and facilitates attachment to other devices on the upstream side.

[0032] To achieve a fluid-tight connection and define the position of the end block relative to the pipe assembly, it is advantageous to securely attach the end block to the burner supply pipe. Similarly, mounted, welded, or integrated solutions can be used.

[0033] Furthermore, it is advantageous that the outer protective tube is also securely connected to the end block. To avoid unacceptable thermal stress caused by the different thermal expansion of the burner supply pipe and the outer protective tube, it is particularly advantageous that the outer protective tube includes some corrugations.

[0034] An impermeable connection between one of the inner tubes and the end block is required, but less important than that between the outer tubes. To avoid thermal stress at the first and / or second fluid supply tubes, connections are preferably provided, for example, between the first fluid supply tube and the end block, and between the second fluid supply tube and the end block, respectively, by fitting the upstream end of the fluid supply tube within a sleeve. This allows for relative thermal expansion.

[0035] The arrangement of the first fluid supply pipe within the burner supply pipe creates an annular free space, which is advantageously used as an annular fluid passage to guide, in particular, gaseous fuel or combustion gas, to the burner. Therefore, it is advantageous that the width of the annular fluid passage, i.e., the distance between the inner side of the burner supply pipe and the outer side of the first fluid supply pipe, is at least 0.05 times the pipe diameter. If the width of the annular fluid passage is preferably no greater than 0.3 times the pipe diameter, it is possible to advantageously utilize the first supply pipe to guide additional media, such as gaseous fuel or combustion gas, within the first supply pipe. Particularly advantageous here is that the width of the annular fluid passage is at least 0.1 times and / or at most 0.2 times the pipe diameter.

[0036] If the inner side of the burner supply pipe is thickened, it is obvious that the distance to the first fluid supply pipe at the location of the fluid channel will be locally reduced. Since the fluid channel includes a spiral shape, the thickening can have a beneficial effect on the fluid flow within the annular fluid channel. Therefore, it is advantageous that the thickened portion inside the burner supply pipe is at least 0.2 times the width of the annular fluid channel. On the other hand, free space should be left from the thickened portion to the first fluid supply pipe. Therefore, it is advantageous that the thickened portion inside the burner supply pipe is at most 0.7 times the width of the annular channel. Particularly advantageous is that the height of the thickened portion inside is at least 0.3 times and / or at most 0.6 times the width of the annular channel. Attached Figure Description

[0037] An example of the pipe assembly of the present invention having the burner supply pipe of the present invention is shown in the following figures:

[0038] Figure 1 A longitudinal section of an example pipe assembly is shown;

[0039] Figure 2 An exemplary burner supply pipe of the present invention is shown; and

[0040] Figure 3 The fuel passage of the burner supply pipe is shown in detail. Detailed Implementation

[0041] exist Figure 1The exemplary pipe assembly 31 between the burner 32 located at the downstream pipe end and the end block at the upstream pipe end 03 is shown in longitudinal section. The pipe assembly 31 includes an outer protective pipe 33 on its outer side, which is securely connected to the burner 32 at the downstream side 04 and securely connected to the end block at the upstream pipe end 03. To prevent terminal stress within the pipe assembly 31, the outer protective pipe 33 includes a bellows. Furthermore, a mounting bracket is attached to another bellows and in between to the outer protective pipe 33.

[0042] An exemplary burner supply pipe 01 is arranged next to the outer protective pipe 33. The burner supply pipe 01 is also securely connected to the burner 32 at the downstream pipe end 04 and the end block at the upstream pipe end 03. The burner supply pipe 01 includes an integrated fuel passage 11, the length of which is approximately equal to the length of the helical shape.

[0043] A first fluid supply pipe 34 is arranged within the burner supply pipe 01. This first fluid supply pipe is also securely connected to the burner 32. To prevent terminal stress, the first fluid supply pipe 34 is connected to an end fitting at an upstream pipe end 03 with terminal expansion capability. An annular channel is defined between the burner supply pipe 01 and the first fluid supply pipe 34.

[0044] In this example, a second fluid supply pipe 35 is arranged within the first fluid supply pipe 34. This allows additional media to be guided from the upstream pipe end 03 to the burner 32 at the downstream pipe end 04.

[0045] Figure 2 It shows the use in Figure 1 An exemplary burner supply pipe 01 in the pipe assembly 31, wherein, Figure 3 The details of the fuel passage are depicted. The burner supply pipe 01 includes a thin pipe wall 05 with a length 06 and a diameter 07, which is the diameter on the outer side of the pipe wall 05. In this example, the length 06 is approximately four times the diameter 07. The pipe wall 05 is very thin compared to the size of the burner supply pipe 01, and has a thickness 08 that is approximately 0.05 times the diameter 07.

[0046] The burner supply pipe 01 includes a fuel passage 11 as a key feature. This fuel passage has a fuel inlet 12 at the upstream pipe end 03 and a fuel outlet 13 at the downstream pipe end 04 (the fuel outlet 13 is offset in the circumferential direction and therefore not directly visible in this section). After a short distance 17 from the fuel outlet 13, and similarly after a short distance from the fuel inlet 12, the fuel passage 11 includes a spiral shape with a gradient 14.

[0047] In this example, the gradient 14 of fuel passage 11 is approximately 1.5 times that of pipe diameter 07.

[0048] The integration of the fuel passage 11 within the burner supply pipe 01 necessitates the provision of thickenings 15 and 16 on both the inner and outer sides of the pipe wall 05. The inner thickening 16 reduces the distance to the first supply pipe 34. Due to the helical shape of the fuel passage 11, the inner thickening 16 does not obstruct fluid flow within the annular fuel passage. In this example, it is preferable that the fuel passage 11 is arranged with its center radially positioned inside the pipe wall 05. This results in a smaller outer thickening 15 on the outer side of the pipe wall 05 and a higher thickening 16 on the inner side of the pipe wall 05.

Claims

1. A burner assembly having a burner (32) and a tube assembly (31), the tube assembly (31) being attached to the burner (32) located upstream of the tube assembly, and the tube assembly (31) comprising: -External protective tube (33); -The internal first fluid supply pipe (34); as well as - A burner supply pipe (01) is arranged between the outer protective pipe (33) and the first fluid supply pipe (34), wherein the burner supply pipe (01) has - A pipe wall (05) extending along the pipe length (06) from the upstream pipe end (03) to the downstream pipe end (04), the burner supply pipe further having a pipe diameter (07) and a wall thickness (08), wherein the pipe length (06) is at least 2 times and at most 20 times the pipe diameter (07), and the wall thickness (08) is at least 0.01 times and at most 0.2 times the pipe diameter (07), and The burner supply pipe includes at least one integrated fuel passage (11) extending from a fuel inlet (12) at the upstream pipe end (03) to a fuel outlet (13) at the downstream pipe end (04), the equivalent diameter of the fuel passage (11) being at least 0.3 times and at most 3 times the wall thickness (08). It is characterized in that The fuel passage (11) is spiral along most of the length of the pipe (06), and the gradient (14) of the fuel passage is at least 0.5 times and at most 5 times the diameter of the pipe (07), wherein thickening portions (15, 16) due to the fuel passage (11) are arranged on the inner and / or outer sides of the pipe wall (05).

2. The burner assembly according to claim 1, in, The pipe assembly (31) also includes an internal second fluid supply pipe (35).

3. The burner assembly according to claim 1 or 2, in, The local thickness of the burner supply pipe (01) at the fuel passage is at most three times the equivalent diameter; and / or The local thickness of the burner supply pipe (01) at the fuel passage is at most three times the wall thickness (08).

4. The burner assembly according to claim 1 or 2, in, The length of the pipe (06) is at least 4 times and / or at most 10 times the diameter of the pipe (07).

5. The burner assembly according to claim 1 or 2, in, The burner supply pipe includes one or two fuel passages (11).

6. The burner assembly according to claim 1 or 2, in, The distance from the fuel inlet to the spiral shape and the distance from the fuel outlet to the spiral shape are at most 1 times the diameter of the pipe (07).

7. The burner assembly according to claim 1 or 2, in, The distance from the fuel inlet to the spiral shape and the distance from the fuel outlet to the spiral shape are at most 0.5 times the diameter of the pipe (07).

8. The burner assembly according to claim 1 or 2, in, The fuel inlet (12) and / or the fuel outlet (13) are arranged on the outside of the burner supply pipe (01).

9. The burner assembly according to claim 1 or 2, wherein, The fuel passage (11) is arranged such that the center of the fuel passage is between the middle and the inner side of the pipe wall (05).

10. The burner assembly according to claim 1 or 2, in, The external protective tube (33) is securely connected to the burner (32) and is securely connected to the end block at the end of the upstream tube, and includes a bellows.

11. The burner assembly according to claim 10, in, The external protective tube (33) is securely connected to the mounting bracket.

12. The burner assembly of claim 10, wherein, The burner supply pipe (01) is securely connected to the burner (32) and is securely connected to the end block at the end of the upstream pipe; and / or The first fluid supply pipe (34) and / or the second fluid supply pipe (35) are securely connected to the burner (32), while thermal expansion may occur at the upstream pipe end at the end block.

13. The burner assembly according to claim 1 or 2, in, An annular fluid channel is defined between the burner supply pipe (01) and the first fluid supply pipe (34), the annular fluid channel having a channel width between the burner supply pipe (01) and the first fluid supply pipe (34), wherein the channel width is at least 0.05 times and at most 0.3 times the pipe diameter (07).

14. The burner assembly according to claim 13, in, The channel width is at least 0.1 times and at most 0.2 times the pipe diameter (07).

15. The burner assembly according to claim 1 or 2, in, The local distance from the first fluid supply pipe (34) to the thickened portion at the fuel passage is at least 0.2 times and at most 0.7 times the width of the passage.

16. The burner assembly according to claim 1 or 2, in, The local distance from the first fluid supply pipe (34) to the thickened portion at the fuel passage is at least 0.3 times and at most 0.6 times the width of the passage.

17. The burner assembly according to claim 1 or 2, in, The wall thickness (08) is at least 0.02 times and / or at most 0.1 times the pipe diameter (07).

18. The burner assembly according to claim 1 or 2, in, The equivalent diameter is at least 0.6 times and / or at most 1.5 times the wall thickness (08).

19. The burner assembly according to claim 1 or 2, wherein, The gradient (14) is at least 1 and / or at most 2.5 times the pipe diameter (07).

20. The burner assembly of claim 10, in, The distance from the fuel inlet to the spiral shape and the distance from the fuel outlet to the spiral shape are at most 1 times the diameter of the pipe (07).

21. The burner assembly according to claim 10, in, The distance from the fuel inlet to the spiral shape and the distance from the fuel outlet to the spiral shape are at most 0.5 times the pipe diameter (07).

22. The burner assembly according to claim 10, in, The fuel inlet (12) and / or the fuel outlet (13) are arranged on the outside of the burner supply pipe (01).

23. The burner assembly according to claim 1 or 2, in, The fuel passage (11) is arranged such that the center of the fuel passage is between the middle and the inner side of the pipe wall (05).

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