A micro-mixing coupled micro-diffusion composite combustion device fueled by hydrogen

Abstract

The present application relates to the technical field of compound combustion, and particularly relates to a micro-mixing and coupling micro-diffusion compound combustion device using hydrogen as fuel.In the device, a first shell is provided with a plurality of hydrogen inlets and air inlets, the flow direction of the air is perpendicular to the flow direction of the hydrogen, a micro-mixing nozzle and a micro-diffusion nozzle are arranged in the first shell, the hydrogen and the air can be mixed in the micro-mixing nozzle, a through channel is arranged on the central axis of the first shell, the through channel is provided with a duty fuel nozzle, and the micro-mixing nozzle and the micro-diffusion nozzle are uniformly arranged around the duty fuel nozzle; a second shell is connected with the first shell, the outlet ends of the micro-mixing nozzle and the micro-diffusion nozzle are located in the second shell, and a duty combustion zone, a premixed combustion zone and a diffusion combustion zone are formed in the second shell, and the hydrogen and the air can be mixed at the outlet ends of the micro-diffusion nozzle.The above scheme can solve the problems of unstable backfire, increased nitrogen oxide emission and thermal acoustic oscillation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compound combustion, in particular to a micro-mixing coupled micro-diffusion compound combustion device using hydrogen as fuel. BACKGROUND

[0002] Hydrogen has no carbon emission in the combustion process and can be used as a carbon-free alternative fuel for gas turbine combustion power generation.

[0003] Hydrogen has extreme physical properties, which can easily cause problems such as backfire instability, increased nitrogen oxide emission, and thermal acoustic oscillation in the combustion device. Therefore, it is necessary to propose a micro-mixing coupled micro-diffusion compound combustion device using hydrogen as fuel to solve the above technical problems. SUMMARY

[0004] The present application provides a micro-mixing coupled micro-diffusion compound combustion device using hydrogen as fuel, which can solve the problems of backfire instability, increased nitrogen oxide emission, and thermal acoustic oscillation.

[0005] The present application provides a micro-mixing coupled micro-diffusion compound combustion device using hydrogen as fuel, which comprises:

[0006] The first shell is provided with a plurality of hydrogen inlets and air inlets, the flow direction of the air is perpendicular to the flow direction of the hydrogen, a micro-mixing nozzle and a micro-diffusion nozzle are arranged in the first shell, the hydrogen and the air can be mixed in the micro-mixing nozzle, the center axis of the first shell is provided with a through channel, the through channel is provided with a duty fuel nozzle, and the micro-mixing nozzle and the micro-diffusion nozzle are uniformly arranged around the duty fuel nozzle.

[0007] The second shell is connected with the first shell, the outlet ends of the micro-mixing nozzle and the micro-diffusion nozzle are located in the second shell, and the second shell forms a duty combustion zone, a premixed combustion zone and a diffusion combustion zone, and the hydrogen and the air can be mixed at the outlet end of the micro-diffusion nozzle.

[0008] The present application provides a micro-mixing coupled micro-diffusion compound combustion device using hydrogen as fuel, which comprises a micro-mixing nozzle and a micro-diffusion nozzle arranged in the first shell, and a duty fuel nozzle arranged through the first shell, that is, a scheme of combined arrangement of the micro-mixing nozzle and the micro-diffusion nozzle, which can effectively avoid backfire problem, shorten high-temperature flue gas residence time, and reduce nitrogen oxide emission; at the same time, due to the different types of the micro-mixing nozzle, the micro-diffusion nozzle and the duty fuel nozzle, the difference in natural frequency is realized, and vortex flow is formed in the combustion area (i.e. the A, B, C and D areas), so that the thermal acoustic oscillation can be reduced, and the combustion instability problem can be effectively avoided. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 A cross-sectional schematic diagram of a micro-mixing coupled micro-diffusion composite combustion device using hydrogen as fuel provided by one embodiment of the present invention;

[0011] Figure 2 for Figure 1 A schematic cross-sectional view of a micro-mixing nozzle in the composite combustion device shown;

[0012] Figure 3 for Figure 1 A schematic cross-sectional view of a micro-diffusion nozzle in the composite combustion device shown;

[0013] Figure 4 for Figure 1 A top view of the micro-mixing nozzle, micro-diffusion nozzle and service fuel nozzle in the composite combustion device is shown.

[0014] Reference numerals:

[0015] 1- first shell;

[0016] 11- Hydrogen inlet;

[0017] 12- Air inlet;

[0018] 13-upper housing;

[0019] 14-lower housing;

[0020] 15- first partition;

[0021] 16-first mixed space;

[0022] 17-Second mixed space;

[0023] 2- second shell;

[0024] 21-inner shell;

[0025] 22-first inert gas inlet;

[0026] 23- inert gas channel;

[0027] 24-second inert gas inlet;

[0028] 25- third inert gas inlet;

[0029] 26-heat exchange pipeline;

[0030] 3-micro mixing nozzle;

[0031] 31-inlet hole;

[0032] 32-spiral inlet section;

[0033] 33-scaling section;

[0034] 34-outlet hole;

[0035] 4-micro diffusion nozzle;

[0036] 41-inner pipe;

[0037] 42-outer pipe;

[0038] 43-air passage;

[0039] 44-spiral piece;

[0040] 5-on-duty fuel nozzle;

[0041] A, B, C, D-vortex area; X-on-duty combustion area; Y-diffusion combustion area; Z-premixed combustion area; e-on-duty fuel flow direction; f-hydrogen flow direction; g-air flow direction; h-inert gas flow direction. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0043] As shown in Figure 1 The embodiments of the present application provide a micro mixing and micro diffusion combined composite combustion device using hydrogen as fuel, which comprises:

[0044] A first shell 1 is provided with a plurality of hydrogen inlets 11 and air inlets 12, the flow direction of air is perpendicular to the flow direction of hydrogen, a micro mixing nozzle 3 and a micro diffusion nozzle 4 are arranged in the first shell 1, hydrogen and air can be mixed in the interior of the micro mixing nozzle 3, the central axis of the first shell 1 is provided with a through channel, the through channel is provided with an on-duty fuel nozzle 5, and the micro mixing nozzle 3 and the micro diffusion nozzle 4 are uniformly arranged around the on-duty fuel nozzle 5;

[0045] The second shell 2 is connected with the first shell 1, and the outlet ends of the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 are located in the second shell 2, and the second shell 2 forms a duty combustion zone, a premixed combustion zone and a diffusion combustion zone, and hydrogen and air can be mixed at the outlet end of the micro-diffusion nozzle 4.

[0046] In the embodiment, by arranging the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 in the first shell 1 and penetratingly arranging the duty fuel nozzle 5, that is, by adopting the combined arrangement scheme of the micro-mixing nozzle 3 and the micro-diffusion nozzle 4, the backfire problem can be effectively avoided, the high-temperature flue gas residence time is shortened, and the nitrogen oxide emission is reduced; at the same time, due to the different types of the micro-mixing nozzle 3, the micro-diffusion nozzle 4 and the duty fuel nozzle 5, the difference in the natural frequency is realized, and the vortex (that is, the vortex area where A, B, C and D are located) is formed in the combustion area, so that the thermal-acoustic oscillation can be reduced, and the combustion instability problem can be effectively avoided.

[0047] Moreover, the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 are both arranged in millimeter level, and the flow rate in the pipe is high, so that the high-temperature flue gas residence time can be shortened, and the nitrogen oxide emission can be reduced. In addition, the fuel direction (that is, the hydrogen direction) is perpendicular to the air direction, so that the mixing uniformity of the main combustion stage fuel air can be improved.

[0048] It can be understood that the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 are relatively independent, and can be modularly arrayed and expanded according to the load demand, so that the expansibility is good. Figure 4 For example, the duty fuel nozzle 5 can be provided with at least one, the micro-diffusion nozzle 4 can be provided with at least eight, and the micro-mixing nozzle 3 can be provided with at least twenty-eight, and when the required power increases, the number of each nozzle can be increased.

[0049] In some embodiments, the above-mentioned composite combustion device can be applied to a gas turbine and a gas boiler combustion chamber, and is not specifically limited here.

[0050] In some embodiments, the second shell 2 gradually reduces the flow area along the combustion area to the outlet area, so as to increase the flame injection speed and intensity.

[0051] In an embodiment of the present application, the first shell 1 comprises an upper shell 13 and a lower shell 14 connected with each other, the upper shell 13 is connected with the second shell 2, the hydrogen inlet 11 is arranged at the bottom of the lower shell 14, and the air inlet 12 is arranged on the periphery of the upper shell 13.

[0052] The first partition 15 is arranged between the upper shell 13 and the lower shell 14, the lower shell 14 and the first partition 15 form a first mixing space 16, the upper shell 13, the first partition 15 and the second shell 2 form a second mixing space 17, the inlet ends of the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 are located in the first mixing space 16, the periphery of the micro-mixing nozzle 3 is provided with an air inlet hole 31, and air can enter the micro-mixing nozzle 3 in sequence through the air inlet 12, the second mixing space 17 and the air inlet hole 31 and then be mixed with hydrogen.

[0053] In the embodiment, by adopting the first mixing space 16 combined with the two-stage mixing mode of the micro-mixing nozzle 3, the hydrogen and air are mixed in the millimeter scale, so that more uniform premixed gas of hydrogen and air than the traditional swirl premix burner can be obtained, and the peak flame temperature in the combustion process can be reduced, and the nitrogen oxide emission reduction effect is better. Moreover, since the flames formed by the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 are relatively small and the temperature distribution is uniform, the length of the combustion chamber flame tube can be greatly shortened.

[0054] In an embodiment of the present application, the bottom of the micro-mixing nozzle 3 and the micro-diffusion nozzle 4 is provided with a spiral air inlet section 32, and the spiral air inlet section 32 is located in the first mixing space 16.

[0055] In the embodiment, by arranging the spiral air inlet section 32 at the bottom of the micro-mixing nozzle 3 and the micro-diffusion nozzle 4, the uniformity of hydrogen in the first mixing space 16 can be improved, thereby facilitating the improvement of the subsequent fuel-air mixing uniformity.

[0056] In an embodiment of the present application, the micro-mixing nozzle 3 is provided with a converging section 33, the converging section 33 is located in the second mixing space 17, and the converging section 33 is arranged between the air inlet hole 31 and the outlet end of the micro-mixing nozzle 3.

[0057] In the embodiment, by arranging the converging section 33 in the micro-mixing nozzle 3, the uniformity of the fuel-air (i.e. hydrogen and air) mixing can be further improved, the emission of nitrogen oxides is reduced, the turbulence intensity of the mixed gas is improved, the stability of the flame is improved, and the boundary of stable operation of the burner is widened.

[0058] In an embodiment of the present application, the outlet end of the micro-mixing nozzle 3 is in a circular truncated cone structure, and the outer top plane and the side conical surface of the outlet end are provided with air outlet holes 34. In this way, the stability of combustion can be ensured, that is, the ignition performance of the burner is improved.

[0059] In one embodiment of the present application, the micro-diffusion nozzle 4 comprises an inner pipe 41 and an outer pipe 42, the inlet end of the inner pipe 41 is located in the first mixing space 16, and the outlet end is located in the second shell 2, the outer pipe 42 is located in the second mixing space 17, and the air passage 43 is formed between the outer pipe 42 and the inner pipe 41, and the air can enter the second shell 2 after sequentially passing through the air inlet 12, the second mixing space 17, the air passage 43, and then mixed with the hydrogen.

[0060] In one embodiment of the present application, a spiral blade 44 is arranged between the inner pipe 41 and the outer pipe 42. In this way, the turbulence intensity of the air can be improved, thereby facilitating the improvement of the air-fuel mixing uniformity.

[0061] In one embodiment of the present application, a plurality of second partitions are arranged in the lower shell 14, and the lower shell 14, the second partitions, and the first partition 15 form a plurality of first mixing spaces 16, and the number of micro-mixing nozzles 3 and micro-diffusion nozzles 4 in each first mixing space 16 is the same.

[0062] All the micro-diffusion nozzles 4 are uniformly and crossly distributed (for example, crossly distributed in the Figure 4 A group of micro-diffusion nozzles 4 is arranged between two groups of micro-mixing nozzles 3 of two adjacent first mixing spaces 16.

[0063] In the present embodiment, the plurality of micro-mixing nozzles 3 are arranged in the form of four main combustion zone arrays, and thus the flames emitted by the micro-mixing nozzles 3 are relatively dispersed in the radial direction, the heat release is relatively uniform, and the flame transmission and stabilization are facilitated.

[0064] In one embodiment of the present application, the second shell 2 is internally provided with an inner shell 21, the periphery of the second shell 2 is provided with a first inert gas inlet 22 (i.e. an inlet through which the inert gas enters the second shell 2 along an inert gas flow direction), an inert gas passage 23 is formed between the second shell 2 and the inner shell 21, the periphery of the inner shell is provided with a second inert gas inlet 24 and a third inert gas inlet 25, the diameters of the second inert gas inlet 24 and the third inert gas inlet 25 are different, and the inert gas can enter the inner shell 21 after sequentially passing through the first inert gas inlet 22, the inert gas passage 23, and the second inert gas inlet 24, and the inert gas can enter the inner shell 21 after sequentially passing through the first inert gas inlet 22, the inert gas passage 23, and the third inert gas inlet 25.

[0065] In the present embodiment, by introducing the inert gas into the second shell 2, a vortex can be formed in the combustion area to reduce the thermal acoustic oscillation, and the problem of unstable combustion can be effectively avoided.

[0066] In some embodiments, the inert gas can be nitrogen, which is not specifically limited herein.

[0067] In one embodiment of the present invention, a heat exchange pipe 26 is provided inside the inner shell 21, and the heat exchange pipe 26 is provided between the second inert gas inlet 24 and the third inert gas inlet 25. This arrangement can effectively improve the cooling efficiency of the inner shell 21, and the heat of this part can be utilized through the heat exchange pipe 26 (such as circulating water) to improve energy utilization efficiency. It can also reduce NO by cooling the high-temperature and high-pressure gas. X generation and reduce pollutant emissions.

[0068] The following describes the movement and combustion process of hydrogen and air.

[0069] by Figure 1 For example, hydrogen enters the first mixing space 16 through flow direction f, and enters the micro-mixing nozzle 3 and the micro-diffuser nozzle 4 respectively through the spiral air inlet section 32, the compressed air enters the second mixing space 17 through the air inlet 12 along the air flow direction g, and enters the micro-mixing nozzle 3 through the air inlet hole 31 to be premixed with the hydrogen that has entered the micro-mixing nozzle 3, the mixed gas is ejected through the air outlet 34, and ignites in the combustion chamber (i.e., in the second shell 2, specifically in the inner shell 21) to form a premixed combustion zone Z (or main combustion zone); the compressed air passes through the air channel 43 and rotates along the spiral sheet 44 to form a swirl gas, and ignites with the hydrogen that has entered the micro-diffuser nozzle 4 in the combustion chamber to form a diffusion combustion zone Y (or secondary combustion zone), and the secondary combustion zone is arranged around the main combustion zone (i.e., the diffusion combustion zone Y is arranged around the premixed combustion zone Z); the duty fuel directly enters the combustion chamber along the flow direction e through the duty fuel nozzle 5 and is ignited to form the duty combustion zone X, and the duty combustion zone X is arranged in the inner center of the diffusion combustion zone Y and the premixed combustion zone Z.

[0070] It should be noted that, in this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the presence of other identical factors in the process, method, article or device comprising the elements.

[0071] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A micro-mixing coupled micro-diffusion composite combustion device using hydrogen as fuel, characterized in that: include: A first shell (1) is provided with a plurality of hydrogen inlets (11) and air inlets (12), the flow direction of the air is perpendicular to the flow direction of the hydrogen, a micro-mixing nozzle (3) and a micro-diffusion nozzle (4) are provided in the first shell (1), hydrogen and air can be mixed inside the micro-mixing nozzle (3), a through-channel is provided on the central axis of the first shell (1), a duty fuel nozzle (5) is provided on the through-channel, and the micro-mixing nozzle (3) and the micro-diffusion nozzle (4) are evenly arranged around the duty fuel nozzle (5); A second shell (2) is connected to the first shell (1), wherein the outlet ends of the micro-mixing nozzle (3) and the micro-diffusion nozzle (4) are both located in the second shell (2), and a duty combustion zone, a premixing combustion zone and a diffusion combustion zone are formed in the second shell (2), and hydrogen and air can be mixed at the outlet end of the micro-diffusion nozzle (4); The first shell (1) comprises an upper shell (13) and a lower shell (14) connected to each other, the upper shell (13) is connected to the second shell (2), the hydrogen inlet (11) is arranged at the bottom of the lower shell (14), and the air inlet (12) is arranged around the upper shell (13); A first partition (15) is provided between the upper shell (13) and the lower shell (14); the lower shell (14) and the first partition (15) form a first mixing space (16); the upper shell (13), the first partition (15) and the second shell (2) form a second mixing space (17); the inlet ends of the micro-mixing nozzle (3) and the micro-diffusion nozzle (4) are both located in the first mixing space (16); an air inlet hole (31) is provided around the micro-mixing nozzle (3); air can enter the micro-mixing nozzle (3) through the air inlet (12), the second mixing space (17) and the air inlet hole (31) in sequence and then be mixed with hydrogen; The micro-diffusion nozzle (4) comprises an inner pipe (41) and an outer pipe (42); the inlet end of the inner pipe (41) is located in the first mixing space (16), and the outlet end is located in the second shell (2); the outer pipe (42) is located in the second mixing space (17); an air channel (43) is formed between the outer pipe (42) and the inner pipe (41); air can sequentially enter the second shell (2) through the air inlet (12), the second mixing space (17), and the air channel (43) and then be mixed with hydrogen; A spiral sheet (44) is provided between the inner pipe (41) and the outer pipe (42); A plurality of second partitions are provided in the lower shell (14); the lower shell (14), the second partitions and the first partition (15) form a plurality of first mixing spaces (16); the number of the micro-mixing nozzles (3) and the micro-diffusing nozzles (4) in each of the first mixing spaces (16) is the same; All the micro-diffusion nozzles (4) are evenly cross-distributed, and one group of the micro-diffusion nozzles (4) is arranged between two groups of the micro-mixing nozzles (3) in two adjacent first mixing spaces (16); The bottoms of the micro-mixing nozzle (3) and the micro-diffusing nozzle (4) are both provided with spiral air inlet sections (32), and the spiral air inlet sections (32) are located in the first mixing space (16).

2. The device according to claim 1, characterized in that The micro-mixing nozzle (3) is provided with a convergent section (33), the convergent section (33) is located in the second mixing space (17), and the convergent section (33) is provided between the air inlet hole (31) and the outlet end of the micro-mixing nozzle (3).

3. The device according to claim 1, characterized in that The outlet end of the micro-mixing nozzle (3) is in a truncated cone-shaped structure, and both the outer top plane and the side conical surface of the outlet end are provided with air outlet holes (34).

4. The device according to any one of claims 1 to 3, characterized in that An inner shell (21) is provided inside the second shell (2), a first inert gas inlet (22) is provided around the second shell (2), an inert gas channel (23) is formed between the second shell (2) and the inner shell (21), a second inert gas inlet (24) and a third inert gas inlet (25) are provided around the inner shell, the second inert gas inlet (24) and the third inert gas inlet (25) having different calibers, inert gas can sequentially enter the inner shell (21) through the first inert gas inlet (22), the inert gas channel (23), and the second inert gas inlet (24), and inert gas can sequentially enter the inner shell (21) through the first inert gas inlet (22), the inert gas channel (23), and the third inert gas inlet (25).

5. The device according to claim 4, characterized in that A heat exchange pipeline (26) is provided inside the inner shell (21), and the heat exchange pipeline (26) is provided between the second inert gas inlet (24) and the third inert gas inlet (25).

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