Combustion chamber for the combustion of hydrogen

Abstract

The invention relates to a combustion chamber (01) as part of a combustion device (11) and is used for the combustion of hydrogen with oxygen. Said combustion chamber extends along a chamber axis and has a combustion space (02) which is surrounded by an inner surface (05). At the upstream end there is a receiving opening (03) for the arrangement of a hydrogen burner (12), and at the downstream end there is an outlet opening (04) for the discharge of water vapor. The combustion chamber (01) can be divided into a combustion section (06), a transition section (07) and an outlet section (08). A cooling channel (23) is also required. The residual amount of unburned hydrogen and oxygen can be reduced by virtue of the heat transfer from the combustion space (02) to the cooling channel (23) in the region of the transition section (07) and outlet section (08) being increased, and by virtue of the free cross section (18) being continuously decreased in size in the outlet section (08).

Description

2024PF00570 Foreign version 1 Description Combustion chamber for the combustion of hydrogen

[0001] The invention relates to a combustion chamber of a combustion device for generating steam and / or superheating a steam stream by the combustion of hydrogen with oxygen. BACKGROUND

[0002] Combustion units with such combustion chambers are used, among other things, in power plants where steam turbines drive generators to produce electricity. The combustion unit provides steam capacity in this process. In particular, the possibility of efficiently using hydrogen improves the sustainability of energy production.

[0003] For example, EP 0 452 839 B1 and the WO 2023274661 A1 describes a typical combustion chamber, which initially has the shape of a cylinder. Hydrogen and oxygen are supplied at the upstream end and combust in the combustion chamber of the combustion device. The resulting steam is discharged downstream and is thus available, for example, to a steam turbine.

[0004] A well-known problem with the combustion of hydrogen with oxygen is the extremely high combustion temperatures. Without appropriate countermeasures, this leads to immediate damage to the combustion system. Therefore, cooler steam or water from other sources is typically introduced into the combustion chamber to cool the components and lower the maximum adiabatic combustion temperature. Furthermore, it is common practice to... 2024PF00570 Foreign version 2 To cool the combustion chamber within the wall or at least on the outside by a cooling medium.

[0005] The highest possible target temperature should be achieved at the outlet of the combustion unit, while preventing thermal damage to downstream pipes and system components. This ensures that the largest possible amount of heat is transported with the generated steam.

[0006] The aim is to achieve the most complete possible combustion of the supplied hydrogen and oxygen to water vapor without any remaining residue of either reactant. However, the usual measures for cooling the combustion chamber and achieving the desired target temperature make it difficult to avoid residual hydrogen and oxygen due to the required mixing with directly supplied steam. SUMMARY OF THE INVENTION

[0008] The object of the present invention is to enable the combustion of hydrogen with oxygen in such a way that, on the one hand, a target temperature can be set and, on the other hand, as few residues of hydrogen and / or oxygen as possible remain. The problem is solved by an embodiment of a combustion chamber according to the invention as described in claim 1. A combustion device according to the invention is specified in claim 10. Advantageous embodiments are the subject of the dependent claims.

[0010] The combustion chamber, as part of a combustion system, serves to combust hydrogen with oxygen. It extends along a chamber axis and has a combustion chamber enclosed by an inner surface. At the upstream end is an inlet opening for the installation of a hydrogen burner, and at the downstream end is an outlet opening for the combustion gases. 2024PF00570 Foreign version 3 Release of water vapor. The combustion chamber can be divided into a combustion section, a transition section, and an exhaust section. A cooling channel is also required.

[0011] By increasing the heat transfer from the combustion chamber to the cooling channel in the transition and exhaust sections, and by continuously reducing the free cross-section in the exhaust section, the residual amount of unburned hydrogen and oxygen can be reduced while still achieving the target temperature. Furthermore, the circumference of the combustion chamber relative to its cross-section is designed to increase continuously in the exhaust section. DESCRIPTION OF THE INVENTION

[0012] A combustion chamber of this type is an integral part of a combustion device designed for the combustion of hydrogen with oxygen. The combustion chamber extends along a central axis. Inside the combustion chamber is the combustion chamber where the combustion takes place. The surface facing the combustion chamber is formed by an inner surface. At the upstream end, an opening is required for the installation of a hydrogen burner. At the downstream end, there is an outlet opening for the release of water vapor.

[0013] The combustion chamber can be divided into three sections between the intake and exhaust ports. Downstream of the burner, following the intake port, is a combustion section. A transition section is located in the middle section, and an exhaust section is located downstream of the exhaust port. The combustion chamber should have a substantially constant cross-section in the combustion and transition sections. This is considered to be the case if the free cross-section varies by a maximum of 10%, and preferably by a maximum of 5%, along the combustion and transition sections. 2024PF00570 Foreign version 4

[0014] Although only the first section is designated as the combustion section, the intended combustion of hydrogen with oxygen is not limited to this area, but can continue to the outlet opening.

[0015] The free cross-section is defined by a cut perpendicular to the chamber axis as the cross-sectional area of ​​the combustion chamber bounded by the inner surface.

[0016] Furthermore, at least one cooling channel extending along the combustion chamber is required. The design of this channel(s) is initially irrelevant, provided that sufficient cooling of the combustion chamber, i.e., its walls, is possible. [0011 To cool the mixture of supplied steam and steam produced by combustion, the transition section and the outlet section are provided with means for increasing heat transfer from the combustion chamber to the cooling channel. Although heat transfer from the combustion chamber to the cooling channel also occurs in the combustion section, means for increasing heat transport are provided in the transition section and the outlet section, in contrast to the combustion section.

[0018] To cool the mixture of supplied steam and combustion-generated steam, and simultaneously to set the desired target temperature at the outlet opening – instead of the usual additional steam supply – an increase in heat transfer in the outlet section is preferably achieved by a relative increase in surface area. Thus, the ratio of the internal surface area, i.e., more precisely, the circumference of the internal surface in a section perpendicular to the chamber axis, to the free cross-section in the flow direction is continuously increased.

[0019] Furthermore, it is considered essential that the free cross-section in the outlet section decreases steadily in the direction of flow up to the outlet opening. 2024PF00570 Foreign version 5

[0020] To reduce the cross-section and, in particular, to increase the ratio of circumference to cross-section, multiple indentations are provided distributed around the circumference. The specific design of these indentations is initially irrelevant. However, it must be taken into account that the free cross-section decreases along the length of the outlet section towards the outlet opening.

[0021] A particular advantage of using indentations is that the temperature difference within the combustion chamber, from the inner surface to the central chamber axis, can be reduced.

[0022] The indentations can be designed, for example, as triangular or rectangular ribs extending along the chamber axis and into the combustion chamber. Particularly preferably, the indentations have an arc-shaped form, so that in a particularly preferred embodiment the outlet opening has a wave-like shape around its circumference. By increasing the heat transfer according to the invention, while simultaneously reducing the cross-section and increasing the ratio of circumference to cross-section, the target temperature can be reached, and yet the amount of steam supplied for cooling the mixture can be reduced compared to known solutions. This, in turn, enables better combustion of the hydrogen with the oxygen and thus a reduction of any residual hydrogen and / or oxygen.

[0024] To achieve a beneficial effect by reducing the free cross-section in the outlet section, the area of ​​the outlet opening should be no more than 0.8 times the smallest free cross-section in the combustion and transition sections. Smaller free cross-sections directly at the intake opening, such as those found in rounded edges or similar features, should be disregarded. It is particularly advantageous if the area of ​​the outlet opening is no more than 0.6 times the free cross-section in the combustion and transition sections. 2024PF00570 Foreign version 6

[0025] However, the free cross-section should not be too small, and therefore an area of ​​the outlet opening of at least 0.4 times, preferably at least 0.5 times, the free cross-section in the area of ​​the combustion section and transition section is considered to be advantageous. To increase heat transfer in the transition section, a plurality of fins extending into the cooling channel are preferably used. This increases the surface area of ​​the cooling channel. To avoid unnecessarily impeding the flow in the cooling channel, the fins should extend in the direction of the chamber axis.

[0027] Steam is preferably supplied to the cooling channel via a channel inlet at the upstream end of the cooling channel. Depending on the type of cooling channel (at least one), a single channel inlet may suffice. Alternatively, multiple channel inlets may be provided. Furthermore, it is advantageously provided that the cooling channel leads to at least one channel outlet at the downstream end of the combustion chamber. The channel outlet can be located adjacent to the outlet opening. In addition, to supply steam as a coolant directly into the combustion chamber, the cooling channel can be connected to steam nozzles located in the inner surface.

[0030] It should be noted that a common supply of steam from the at least one channel inlet, via the at least one cooling channel to the at least one channel outlet and simultaneously to the steam nozzles is possible. Alternatively, it can be provided that at least one cooling channel leads from at least one channel inlet to at least one channel outlet and another cooling channel leads to the steam nozzles.

[0031] To cool the combustion chamber, i.e., the wall, at least one cooling channel can be designed differently. In one variant, it is possible to... 2024PF00570 Foreign version 7. To provide a plurality of cooling channels distributed around the circumference. This allows a large surface area of ​​the cooling channels to be achieved relative to their cross-section. The individual cooling channels can have a round or, preferably, a rectangular or rounded cross-section, and, depending on the arrangement, a slightly curved cross-section. If multiple cooling channels are present in the outlet section, these and their respective outlets are preferably arranged at least in the area of ​​the indentations. This allows for a short distance for heat transfer from the combustion chamber to the cooling channel. Furthermore, this also facilitates the guidance of the steam flow exiting the outlet opening and the channel outlets of the combustion chamber. In an alternative design, an annular cooling channel is provided. Thus, the combustion chamber has an inner wall on the side facing the combustion chamber and an outer wall on the outside. One option is to design the combustion chamber without any connection between the inner and outer walls along its entire length. Depending on the fastening method at the ends of the combustion chamber, this can prevent thermal stresses between the inner and outer walls. Alternatively, the inner and outer walls can be connected via multiple webs or other connecting elements. In an annular cooling channel, the outlet opening is preferably also annular. The wall thickness of the inner wall in the area of ​​the outlet opening is particularly preferably largely constant around the circumference. This is considered to be the case if the wall thickness varies by no more than + / - 15% from a mean value (as the median). Depending on the design of the combustion process with the supply of hydrogen and oxygen as well as steam and / or water, the three phases can have different lengths. 2024PF00570 Foreign version 8 Sectioning the system can be beneficial. When dividing it, it is advantageous to consider how the means for increasing heat transfer are implemented. It is also important to consider the ratio by which the free cross-section is reduced up to the outlet opening.

[0037] Regardless of the specific design of the burner used in a combustion device and the specific design of the components, a reasonable range for the combustion chamber division can still be specified. This involves first defining the combustion chamber length from the intake opening to the exhaust opening.

[0038] Generally, it is advantageous if the length of the combustion section is at least 0.3 times the combustion chamber length. Conversely, the length of the combustion section, i.e., up to the point where additional means for increasing heat transfer are implemented, should not exceed 0.6 times the combustion chamber length. The reduction of the free cross-section along the length of the exhaust section should advantageously be at least 0.2 times the combustion chamber length. It is particularly advantageous if the length of the exhaust section is at least 0.3 times the combustion chamber length. However, the length of the exhaust section should not exceed 0.6 times the combustion chamber length. It is especially advantageous if the length of the exhaust section is not greater than 0.4 times the combustion chamber length.

[0040] The use of a combustion chamber according to the invention enables the realization of a combustion device according to the invention. This device has a hydrogen burner arranged at the receiving opening at the upstream end and a transition section arranged at the downstream end.

[0041] The hydrogen burner enables the supply of hydrogen via Hydrogen nozzles and the supply of oxygen via oxygen nozzles to 2024PF00570 Foreign version 9 Injection into the combustion chamber. The hydrogen nozzles and / or the oxygen nozzles can advantageously be arranged directly at the intake opening. It is also possible to arrange the hydrogen nozzles and / or the oxygen nozzles inside the burner, in which case combustion within the burner is not intended.

[0042] Furthermore, a steam channel and / or a water channel is required so that steam and / or water can be supplied directly into the combustion chamber via the intake opening.

[0043] Preferably, at least one channel outlet is arranged directly adjacent to the outlet opening. By using steam as a coolant in at least one cooling channel, an advantageous transition section creates a merging of the outlet opening and the channel outlet.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG 1 shows in longitudinal section an exemplary embodiment of a combustion device with a combustion chamber with means for increasing heat transfer.

[0046] FIG 2 sketches a cross-section through the combustion chamber from FIG. 1 in the area of ​​the transition section.

[0047] FIG 3 sketches a cross-section through the combustion chamber from FIG. 1 in the area of ​​the outlet section. DESCRIPTION OF THE EXECUTION FORMS

[0048] Figure 1 schematically shows a combustion device 11 with a combustion chamber 01 according to the invention in a longitudinal section. A hydrogen burner 12 is arranged at the upstream end of the combustion device 11. This burner 12 has as essential elements a vapor channel 13 and 2024PF00570 Foreign version 10 Hydrogen nozzles 14 and oxygen nozzles 15 are installed. Accordingly, the combustion unit 11 is designed to enable the combustion of hydrogen with oxygen in a vapor atmosphere.

[0049] The sketched combustion chamber 01 has an approximately cylindrical shape and extends along a central chamber axis. Inside is the combustion chamber 02, which adjoins the inner surface 05. On the upstream side is a receiving opening 03, at which the hydrogen burner 12 is arranged. On the downstream side is an outlet opening 04 for the release of water vapor formed as a mixture of supplied vapor and vapor generated by combustion.

[0050] The combustion chamber 01 can be divided into three sections. Adjacent to the intake opening 03 is a combustion section 06, followed by a transition section 07. Downstream of the outlet opening 04 is the exhaust section 08. Furthermore, a ring-shaped cooling channel 23 is sketched, which extends over the entire length of the combustion chamber 01 from a channel inlet 27 to a channel outlet 28. Accordingly, on the side facing the combustion chamber 02 with the inner surface 05 there is an inner wall 21 and on the outside an outer wall 22.

[0052] Steam nozzles 16 are also shown, which are arranged distributed around the circumference of the combustion section 06. These are shown purely as examples, and steam nozzles within the combustion chamber are preferably omitted.

[0053] Following combustion chamber 01 is a transfer section 26. In this section, the flow from outlet opening 04 and from channel outlet 28 is combined. 2024PF00570 Foreign version 11

[0054] Essential to the present invention is the provision of means for increasing heat transfer from the combustion chamber 02 to the cooling channel 23. In this embodiment, the transition section 07 is provided with a plurality of circumferentially distributed fins 24 projecting into the cooling channel 23 from the outer surface of the inner wall 21. This effectively increases the surface area for transferring heat energy from the inner wall 21 to the cooling channel 23.

[0055] In this embodiment, the outlet section 08 is designed with a deviation from a round shape to increase the surface area, i.e., the inner surface 05 in the area of ​​the outlet section 08, relative to the volume of the combustion chamber 02. For this purpose, the outlet section 08 has a plurality of circumferentially distributed indentations 25, which extend 25 towards the chamber axis into the combustion chamber 02. This effectively increases the surface area for the transfer of heat energy from the combustion chamber 02 into the inner wall 21.

[0056] Furthermore, according to the invention, the free cross-section in the outlet section 08 decreases continuously along the chamber axis towards the outlet opening 04. Figure 2 shows a cross-section through the combustion chamber 01 in the area of ​​the transition section 07. Visible are the free cross-section 17 with its circular shape, the inner wall 21, and, through the cooling channel 23, the outer wall 22. The numerous fins 24 ensure the necessary means for increasing the heat transfer from the combustion chamber 02 to the cooling channel 23. Figure 3 shows a cross-section through the combustion chamber 01 in the area of ​​the outlet section 08. Also visible is the free cross-section 18, which extends into the wall 21 and, through the cooling channel 23, into the outer wall 22. Due to the numerous indentations 25, both the free cross-section 18 and the inner wall 21 have a similarly star-shaped form.

Claims

2024PF00570 Foreign version 12 Claims What is claimed:

1. Combustion chamber (01) of a combustion device (11) for the combustion of hydrogen with oxygen, which (01) extends along a chamber axis and encloses a combustion chamber (02) with an inner surface (05) and has a receiving opening (03) arranged at the upstream end for the arrangement of a hydrogen burner (12) and an outlet opening (04) arranged at the downstream end for the release of water vapor and has a combustion section (06) and a transition section (07) and an outlet section (08) between the receiving opening (03) and the outlet opening (04) and at least one cooling channel (23) extending along the combustion chamber (02), wherein the free cross-section (17) varies by a maximum of 10% along the combustion section (06) and the transition section (07);wherein the transition section (07) and the outlet section (08) have means for increasing the heat transfer from the combustion chamber (02) to the cooling channel (23), characterized in that a plurality of indentations (25) pointing towards the chamber axis are distributed around the circumference of the outlet section (08), wherein the free cross-section (18) in the outlet section (08) becomes continuously smaller in the flow direction and the ratio of a circumferential length of the inner surface (05) relative to the free cross-section (18) becomes continuously larger in the flow direction.

2. Combustion chamber (01 ) according to claim 1 , wherein the area of ​​the outlet opening (04) corresponds at most to 0.8 times, in particular at most to 0-6 times, the smallest free cross-section (16) of the combustion section (06) and the transition section (07). 2024PF00570 Foreign version 13 3. Combustion chamber (01 ) according to claim 1 or 2, wherein within the transition section (07) a plurality of elevations extending into the cooling channel (23), in particular ribs (24), are arranged distributed around the circumference, which (24) extend in particular along the chamber axis.

4. Combustion chamber (01 ) according to one of claims 1 to 3, wherein the at least one cooling channel (23) leads from a channel inlet at the upstream end of the combustion chamber (01 ) to a channel outlet at the downstream end of the combustion chamber (01 ) and / or to steam nozzles (16) opening into the combustion chamber (02).

5. Combustion chamber (01 ) according to one of claims 1 to 4, wherein a plurality of circumferentially distributed cooling channels and a plurality of circumferentially distributed, in particular each at the position of a respective indentation, channel outlets are provided.

6. Combustion chamber (01 ) according to one of claims 1 to 5, wherein an annular cooling channel (23) is arranged between an inner wall (21) and an outer wall (22).

7. Combustion chamber (01 ) according to claim 6, wherein the wall thickness of the inner wall (21 ) at the outlet opening (04) varies by a maximum of 30%.

8. Combustion chamber (01) according to any one of claims 1 to 7, wherein (01) a combustion chamber length is defined from the intake opening (03) to the outlet opening (04), wherein a length of the combustion section (06) corresponds to at least 0.3 times and / or at most 0.6 times the combustion chamber length; and / or wherein a length of the outlet section (08) corresponds to at least 0.3 times and / or at most 0.6 times the combustion chamber length. 2024PF00570 Foreign version 14 9. Combustion device (11) comprising - a combustion chamber (01) according to one of the preceding claims, and - a hydrogen burner (12) arranged at the upstream end, which (12) has a steam channel (13) or a water channel and several hydrogen nozzles (14) and several oxygen nozzles (15), and - a transfer section (26) located at the downstream end.

10. Combustion device (11) according to claim 9, wherein in the transfer section (26) the outlet opening (04) is joined with the channel outlet (18).

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