Combustor for mixed combustion of ammonia gas and natural gas and operation method of combustor
By designing a burner for ammonia and natural gas, using a combustion operation method that supplies ammonia to the internal supply of natural gas and externally supply of natural gas, rich combustion and externally lean combustion, the problems of flame instability and high NOx emissions during ammonia combustion are solved, and the stable stationary and low emissions of ammonia flame are achieved, and better compatibility with the existing equipment system is achieved.
Patent Information
- Application Number
- CN202510048027.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-13
- Publication Date
- 2025-04-25
AI Technical Summary
When ammonia is burned, due to low fuel activity and slow flame propagation, it is difficult to maintain the flame stably and easily shut down. During combustion, a large amount of fuel-type NOx is generated, causing environmental pollution. The existing natural gas blending method increases pollutant emissions while increasing the combustion intensity of ammonia gas, and requires complex structural transformation of the combustion system.
A burner for mixing ammonia and natural gas is designed, and a combustion operation method is adopted for internal ammonia supply and external natural gas supply, internal rich combustion and external poverty combustion. Through the design of the inner tube, the middle tube and the outer tube, the rich state of ammonia and air and the poor state of natural gas and air are formed, and stable flame and low emissions are achieved in the internal and external flames respectively.
The stable stationary ammonia flame is achieved, the generation of fuel-type NOx is inhibited, and the unburned ammonia is fully burned through oxygen in the external flue gas, ensuring low emissions of ammonia. Compared with the axial hierarchical combustion scheme, the designed radial hierarchical burner does not require hole drilling and axial air intake modification to the combustion chamber wall, which has better compatibility.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of new energy technology, and in particular to a burner for the mixed combustion of ammonia and natural gas and an operation method thereof. Background Art
[0002] At present, the fossil energy system based on coal, oil and natural gas is transitioning to a renewable energy system based on wind, solar and energy storage. In this process, zero-carbon fuel energy storage has shown special advantages in absorbing wind and solar energy and stabilizing the operation of power systems. Among them, ammonia, as a typical zero-carbon energy storage fuel, has great application potential in gas turbines, gas boilers, power station boilers, industrial kilns, internal combustion power and other fields.
[0003] However, when ammonia fuel is burned and utilized, a series of serious combustion problems will occur due to the fact that ammonia has physical and chemical properties that are very different from those of traditional fuels. On the one hand, ammonia has low fuel activity and flame propagation speed, which makes it difficult to maintain a stable ammonia flame, difficult to ignite, and easy to flame out, threatening the safety of equipment operation. On the other hand, since ammonia molecules contain nitrogen, a large amount of fuel-type NOx will be generated when ammonia burns, with a concentration of up to thousands of ppm, which will cause serious pollution to the environment. Therefore, ammonia cannot be directly used in existing combustion equipment, and it is necessary to develop high-flame stability and low-emission combustion control technology based on the characteristics of ammonia fuel.
[0004] The existing natural gas blending method is mainly carried out in a single-stage combustion mode. This method has been proven to effectively improve the flame stability performance of ammonia and expand the flammable limit of ammonia. However, while improving the combustion intensity of ammonia, the blending of natural gas has brought about an increase in pollutant emissions. This is because single-stage combustion often needs to operate under lean combustion conditions, and sufficient oxygen content and increased chemical activity will further aggravate NOx emissions. In order to control NOx emissions at the same time, some scholars have proposed adding a second stage of combustion along the axial direction on the basis of single-stage blending, namely the so-called axial staged combustion. Among them, the first stage is set to a rich ammonia and natural gas blended combustion, and the rich combustion condition can effectively limit the generation of fuel-type NOx; the second stage is set to lean combustion, and the unburned ammonia and natural gas fuel in the first stage are fully burned. This axial staged combustion has a significant effect in synergistically improving the flame stability and pollutant emission performance of ammonia. However, axial staged combustion requires a large structural modification of the existing mainstream full-head intake combustion system. For example, it is necessary to perforate the existing combustion chamber wall and modify the gas distribution method to achieve complex axial segmented intake. Such complex and expensive facility transformation is not conducive to the use of ammonia fuel under the existing equipment system. Summary of the invention
[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a burner for ammonia and natural gas co-combustion, which can meet the performance requirements of ammonia and natural gas co-combustion devices such as high flame stability, low emissions, and compatibility.
[0006] The present application also proposes an operating method for the above-mentioned burner for the mixed combustion of ammonia and natural gas.
[0007] According to the first aspect of the present application, a burner for the mixed combustion of ammonia and natural gas includes:
[0008] An inner tube, an outer wall of which is provided with first swirl blades;
[0009] A middle tube is sleeved on the outer side of the inner tube, a first channel is provided between the inner tube and the middle tube; and a second swirl blade is provided on the outer wall of the middle tube;
[0010] An outer tube, which is sleeved on the outer side of the middle tube, and a second channel is provided between the middle tube and the outer tube;
[0011] The first channel is used to supply a rich mixture of ammonia and air, and the second channel is used to supply a lean mixture of natural gas and air.
[0012] According to the burner for the mixed combustion of ammonia and natural gas according to the embodiment of the present application, there are at least the following beneficial effects: by adopting the combustion operation method of internal ammonia supply and external natural gas supply, internal rich combustion and external lean combustion, in terms of flame stabilization performance, the outer high-intensity natural gas flame can stably support the continuous stationing of the inner low-intensity ammonia flame; in terms of NOx emission performance, the inner ammonia flame burns in a rich combustion state, which can suppress the large-scale generation of fuel-type NOx; in terms of NH3 emission performance, the outer natural gas flame burns in a lean combustion state, and the oxygen rich in the outer flue gas can fully burn the unburned ammonia in the inner stage to ensure low ammonia emissions. At the same time, compared with the existing axial staged combustion scheme, the radial staged burner based on full-head air intake designed by the present invention does not require the combustion chamber wall to be punched and the axial air intake modification, which can avoid large mechanical adjustments and has better compatibility with existing equipment systems.
[0013] According to some embodiments of the present application, the inner tube is provided with a first conical structure at the exit end of the first channel, and the outer diameter of the first conical structure gradually increases along the flow direction of the airflow in the first channel; the middle tube is provided with a flaring structure at the exit end of the first channel, and the inner diameter of the flaring structure gradually increases along the flow direction of the airflow in the first channel.
[0014] According to some embodiments of the present application, the middle tube is provided with a second conical structure at the exit end of the second channel, and the outer diameter of the second conical structure gradually decreases along the flow direction of the airflow in the second channel; the outer tube is provided with a closing structure at the exit end of the second channel, and the inner diameter of the closing structure gradually decreases along the flow direction of the airflow in the second channel.
[0015] According to some embodiments of the present application, the angle of the first swirl blade is 30 to 60°.
[0016] According to some embodiments of the present application, the angle of the second swirl blade is 30 to 75°.
[0017] According to some embodiments of the present application, the burner for the mixed combustion of ammonia and natural gas also includes a base plate, the inner tube and the middle tube are both installed on the base plate, the base plate is provided with a through hole, and the rich ammonia and air mixture can enter the first channel through the through hole.
[0018] According to some embodiments of the present application, the bottom plate is provided with a threaded hole for threaded connection with the inner tube, and the through hole is adjacent to the threaded hole.
[0019] According to some embodiments of the present application, an air inlet is opened on the side of the outer tube, and a lean natural gas and air mixture enters the second channel from the air inlet.
[0020] According to some embodiments of the present application, the inner tube, the middle tube and the outer tube are all coaxially arranged.
[0021] According to the operating method of the second aspect of the present application, the burner for the above-mentioned ammonia and natural gas mixed combustion is carried out, comprising the following steps:
[0022] delivering a rich ammonia and air mixture to the first passage, and delivering a lean natural gas and air mixture to the second passage;
[0023] In a mixture of rich ammonia and air, an equivalence ratio of rich ammonia to air is set at 1 to 1.5; in a mixture of lean natural gas and air, an equivalence ratio of lean natural gas to air is set at 0.6 to 1; a total equivalence ratio of fuel to air in the first channel and the second channel is less than 1;
[0024] The rich ammonia and air mixture is guided by the first swirl blade to generate a swirl flow, and the lean natural gas and air mixture is guided by the second swirl blade to generate a swirl flow;
[0025] The rich ammonia and air mixture is sprayed out from the first passage and burned, and the lean natural gas and air mixture is sprayed out from the second passage and burned.
[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are used to provide further understanding of the technical solution disclosed in the present application and constitute a part of the specification. Together with the embodiments disclosed in the present application, they are used to explain the technical solution disclosed in the present application and do not constitute a limitation on the technical solution disclosed in the present application.
[0028] Figure 1 This is a cross-sectional view of a burner for mixed combustion of ammonia and natural gas according to an embodiment of the first aspect of the present application;
[0029] Figure 2 This is a three-dimensional diagram of the inner tube in a burner for the mixed combustion of ammonia and natural gas according to the first aspect of the present application;
[0030] Figure 3 This is a three-dimensional diagram of a middle tube in a burner for mixed combustion of ammonia and natural gas according to an embodiment of the first aspect of the present application;
[0031] Figure 4 This is a three-dimensional diagram of the outer tube of the burner for the mixed combustion of ammonia and natural gas in the first aspect of the embodiment of the present application;
[0032] Figure 5 This is a three-dimensional diagram of the bottom plate in a burner for the mixed combustion of ammonia and natural gas according to the first aspect of the embodiment of the present application.
[0033] Figure markings: 100 - inner tube, 110 - first swirl blade, 120 - first conical structure, 200 - middle tube, 210 - second swirl blade, 220 - expanding structure, 230 - second conical structure, 300 - outer tube, 310 - closing structure, 320 - air inlet, 400 - first channel, 500 - second channel, 600 - bottom plate, 610 - through hole, 620 - threaded hole. DETAILED DESCRIPTION
[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0035] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0036] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0037] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.
[0038] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0039] The existing natural gas blending method is mainly carried out in a single-stage combustion mode. This method has been proven to effectively improve the flame stability performance of ammonia and expand the flammable limit of ammonia. However, while improving the combustion intensity of ammonia, the blending of natural gas has brought about an increase in pollutant emissions. This is because single-stage combustion often needs to operate under lean combustion conditions, and sufficient oxygen content and increased chemical activity will further aggravate NOx emissions. In order to control NOx emissions at the same time, some scholars have proposed adding a second stage of combustion along the axial direction on the basis of single-stage blending, namely the so-called axial staged combustion. Among them, the first stage is set to a rich ammonia and natural gas blended combustion, and the rich combustion condition can effectively limit the generation of fuel-type NOx; the second stage is set to lean combustion, and the unburned ammonia and natural gas fuel in the first stage are fully burned. This axial staged combustion has a significant effect in synergistically improving the flame stability and pollutant emission performance of ammonia. However, axial staged combustion requires a large structural modification of the existing mainstream full-head intake combustion system. For example, it is necessary to perforate the existing combustion chamber wall and modify the gas distribution method to achieve complex axial segmented intake. Such complex and expensive facility transformation is not conducive to the use of ammonia fuel under the existing equipment system.
[0040] In this regard, the present application proposes a burner for the mixed combustion of ammonia and natural gas. By adopting a combustion operation method of internal ammonia supply and external natural gas supply, and internal rich combustion and external lean combustion, in terms of flame stabilization performance, the outer high-intensity natural gas flame can stably support the continuous stationing of the inner low-intensity ammonia flame; in terms of NOx emission performance, the inner ammonia flame burns in a rich combustion state, which can suppress the large-scale generation of fuel-type NOx; in terms of NH3 emission performance, the outer natural gas flame burns in a lean combustion state, and the rich oxygen in the outer flue gas can fully burn the unburned ammonia in the inner stage to ensure low ammonia emissions. At the same time, compared with the existing axial staged combustion scheme, the radial staged burner based on full-head air intake designed by the present invention does not require the combustion chamber wall to be perforated and the axial air intake to be modified, which can avoid large mechanical adjustments and has better compatibility with existing equipment systems.
[0041] Reference Figure 1 The burner for ammonia and natural gas in the embodiment of the first aspect of the present application comprises an inner tube 100, a middle tube 200 and an outer tube 300. The three are mutually nested, and channels are provided between each other for airflow, thereby separating the inner low-intensity ammonia flame and the outer high-intensity natural gas flame.
[0042] Specifically, refer to Figure 2The outer wall of the inner tube 100 is provided with a first swirl blade 110 for guiding the airflow to form a swirl and increasing the stability of the flame during combustion. The middle tube 200 is sleeved on the outer side of the inner tube 100. A first channel 400 is provided between the inner tube 100 and the middle tube 200. The first channel 400 is used to supply a rich ammonia and air mixture. Figure 3 The outer wall of the middle tube 200 is provided with a second swirl blade 210, which is used to guide the airflow to form a swirl and increase the stability of the flame during combustion. The outer tube 300 is sleeved on the outer side of the middle tube 200, and a second channel 500 is provided between the middle tube 200 and the outer tube 300, and the second channel is used to supply a lean natural gas and air mixture. Therefore, the outer high-intensity natural gas flame can stably support the continuous stationing of the inner low-intensity ammonia flame, and the inner ammonia flame burns in a rich combustion state, which can suppress the large-scale generation of fuel-type NOx.
[0043] Further, the inner tube 100 is provided with a first tapered structure 120 at the exit end of the first channel 400, and the outer diameter of the first tapered structure 120 gradually increases along the flow direction of the airflow in the first channel 400. The middle tube 200 is provided with a flared structure 220 at the exit end of the first channel 400, and the inner diameter of the flared structure 220 gradually increases along the flow direction of the airflow in the first channel 400. The middle tube 200 is provided with a second tapered structure 230 at the exit end of the second channel 500, and the outer diameter of the second tapered structure 230 gradually decreases along the flow direction of the airflow in the second channel 500. Figure 4 The outer tube 300 is provided with a closing structure 310 at the exit end of the second channel 500, and the inner diameter of the closing structure 310 gradually decreases along the flow direction of the airflow in the second channel 500. Thus, a specific internal airflow channel and an external airflow channel are formed.
[0044] Specifically, the angle of the first swirl blade 110 is 30 to 60 degrees, and the angle of the second swirl blade 210 is 30 to 75 degrees. The first swirl blade 110 and the second swirl blade 210 have the same rotation direction.
[0045] Furthermore, the burner for the mixed combustion of ammonia and natural gas further comprises a bottom plate 600, and the inner tube 100 and the middle tube 200 are both mounted on the bottom plate 600. Figure 5 The bottom plate 600 is provided with a through hole 610 , and the rich ammonia and air mixture can enter the first channel 400 through the through hole 610 .
[0046] Furthermore, the bottom plate 600 is provided with a threaded hole 620 for threaded connection with the inner tube 100, and the through hole 610 is adjacent to the threaded hole 620. The number of the through holes 610 can be set to two or more, and the supply efficiency of the mixed gas can be improved by increasing the number of the through holes 610.
[0047] Furthermore, an air inlet 320 is provided on the side of the outer tube 300 , and the lean natural gas and air mixture enters the second channel 500 from the air inlet 320 .
[0048] Furthermore, the inner tube 100, the middle tube 200 and the outer tube 300 are all coaxially arranged to maintain the coaxiality of the three.
[0049] The operating method of the burner for the above-mentioned ammonia and natural gas blending in the second aspect of the present application includes the following steps:
[0050] S100. A rich ammonia and air mixture is delivered to the first channel 400, and a lean natural gas and air mixture is delivered to the second channel 500;
[0051] S200. In the rich ammonia and air mixture, the equivalence ratio of the rich ammonia and air is set to 1 to 1.5; in the lean natural gas and air mixture, the equivalence ratio of the lean natural gas and air is set to 0.6 to 1; the total equivalence ratio of the fuel and air in the first channel 400 and the second channel 500 is less than 1;
[0052] S300. The rich ammonia and air mixture is guided by the first swirl blade 110 to generate a swirl, and the lean natural gas and air mixture is guided by the second swirl blade 210 to generate a swirl;
[0053] S400. A rich ammonia and air mixture is sprayed out from the first passage 400 and burns, and a lean natural gas and air mixture is sprayed out from the second passage 500 and burns.
[0054] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.
Claims
1. A burner for the mixed combustion of ammonia and natural gas, characterized in that: include: An inner tube, an outer wall of which is provided with first swirl blades; A middle tube is sleeved on the outer side of the inner tube, a first channel is provided between the inner tube and the middle tube; and a second swirl blade is provided on the outer wall of the middle tube; An outer tube, which is sleeved on the outer side of the middle tube, and a second channel is provided between the middle tube and the outer tube; The first channel is used to supply a rich mixture of ammonia and air, and the second channel is used to supply a lean mixture of natural gas and air.
2. The burner for the mixed combustion of ammonia and natural gas according to claim 1 is characterized in that: The inner tube is provided with a first conical structure at the exit end of the first channel, and the outer diameter of the first conical structure gradually increases along the flow direction of the airflow in the first channel; the middle tube is provided with a flared structure at the exit end of the first channel, and the inner diameter of the flared structure gradually increases along the flow direction of the airflow in the first channel.
3. The burner for the mixed combustion of ammonia and natural gas according to claim 1 is characterized in that: The middle tube is provided with a second conical structure at the exit end of the second channel, and the outer diameter of the second conical structure gradually decreases along the flow direction of the airflow in the second channel; the outer tube is provided with a closing structure at the exit end of the second channel, and the inner diameter of the closing structure gradually decreases along the flow direction of the airflow in the second channel.
4. The burner for the mixed combustion of ammonia and natural gas according to claim 1 is characterized in that: The angle of the first swirl blade is 30 to 60 degrees.
5. The burner for the mixed combustion of ammonia and natural gas according to claim 1 is characterized in that: The angle of the second swirl blade is 30 to 75 degrees.
6. The burner for the mixed combustion of ammonia and natural gas according to claim 1, characterized in that: The burner for the mixed combustion of ammonia and natural gas also includes a base plate, the inner tube and the middle tube are both mounted on the base plate, the base plate is provided with a through hole, and the rich ammonia and air mixture can enter the first channel through the through hole.
7. The burner for the mixed combustion of ammonia and natural gas according to claim 6 is characterized in that: The bottom plate is provided with a threaded hole for threaded connection with the inner tube, and the through hole is adjacent to the threaded hole.
8. The burner for the mixed combustion of ammonia and natural gas according to claim 1, characterized in that: An air inlet is provided on the side of the outer tube, and a lean natural gas and air mixture enters the second channel from the air inlet.
9. The burner for mixed combustion of ammonia and natural gas according to any one of claims 1 to 8, characterized in that: The inner tube, the middle tube and the outer tube are all coaxially arranged.
10. An operating method for a burner for mixed combustion of ammonia and natural gas according to any one of claims 1 to 9, characterized in that: include: delivering a rich ammonia and air mixture to the first passage, and delivering a lean natural gas and air mixture to the second passage; In a mixture of rich ammonia and air, an equivalence ratio of rich ammonia to air is set at 1 to 1.5; in a mixture of lean natural gas and air, an equivalence ratio of lean natural gas to air is set at 0.6 to 1; a total equivalence ratio of fuel to air in the first channel and the second channel is less than 1; The rich ammonia and air mixture is guided by the first swirl blade to generate a swirl flow, and the lean natural gas and air mixture is guided by the second swirl blade to generate a swirl flow; The rich ammonia and air mixture is sprayed out from the first passage and burned, and the lean natural gas and air mixture is sprayed out from the second passage and burned.