Ammonia-coal co-combustion burner and boiler
By designing an ammonia coal mixed combustion burner, the mixed gas flow with high coal powder and high ammonia gas concentration reacts in an oxygen-free environment, the problem of nitrogen oxide emissions under ammonia coal mixed combustion conditions is solved, and effective nitrogen oxides are achieved Reduce emissions.
Patent Information
- Application Number
- CN202411934366.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-02-18
AI Technical Summary
Under the conditions of mixed ammonia coal combustion, how to reduce the emission of nitrogen oxides and solve the problem of nitrogen oxides pollution to the environment.
Design an ammonia coal mixed combustion burner, including a coal pulverized channel, a coal pulverized concentrator and an ammonia distributor. Through the design of imported powder concentrate and coal powder concentrate, a mixed air flow with high coal powder and high ammonia concentration is formed, and the reaction is carried out in an oxygen-free environment to reduce the production of nitrogen oxides, and the design of ammonia distribution pores is achieved. Effective mixing of ammonia and gas powder mixture airflow.
The emission of nitrogen oxides is effectively reduced, and the high concentration of coal powder and ammonia is mixed, and the production of nitrogen oxides is reduced, and it is converted into nitrogen through reduction reaction.
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Figure CN119468197A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of boilers, and more specifically, to an ammonia-coal co-firing burner and a boiler. Background Art
[0002] Coal-fired power generation is an important part of the current energy structure, and its carbon dioxide emissions account for about 40% of the total emissions. Therefore, reducing carbon emissions from coal-fired power generation is the key to reducing carbon emissions. Ammonia, as a carbon-free fuel, has a wide range of application potentials, and co-firing with coal can effectively reduce carbon dioxide emissions. Ammonia-coal co-firing technology, as an innovative way to utilize clean energy, has received widespread attention in recent years.
[0003] Ammonia-coal co-combustion technology achieves fossil fuel substitution by mixing ammonia in coal-fired boilers for combustion, significantly reducing carbon dioxide emissions. It has attracted widespread attention in the energy field because of its potential to replace traditional fossil fuels. However, ammonia itself contains a large amount of nitrogen, which easily produces a large amount of nitrogen oxides (NOx) during combustion, which will cause new pollution problems to the environment.
[0004] Therefore, how to reduce nitrogen oxide emissions under mixed ammonia combustion conditions is an urgent problem to be solved by those skilled in the art. Summary of the invention
[0005] In view of this, the object of the present application is to provide an ammonia-coal co-combustion burner to reduce nitrogen oxide emissions under co-combustion conditions; Another object of the present application is to provide a boiler having the above-mentioned ammonia-coal co-firing burner.
[0006] To achieve the above objectives, this application provides the following technical solutions: The first aspect of the present application provides an ammonia-coal co-combustion burner, comprising: A pulverized coal channel, wherein an imported pulverized coal concentrator is provided in the pulverized coal channel; A pulverized coal concentrator, disposed in the pulverized coal channel and located downstream of the inlet pulverizer; An ammonia distributor, at least part of its structure is located in the pulverized coal channel, and passes through the inlet concentrator and the pulverized coal concentrator. A pulverized coal airflow channel is formed between the ammonia distributor and the pulverized coal channel, a primary channel is formed between the ammonia distributor and the pulverized coal concentrator, and a secondary channel is formed between the pulverized coal concentrator and the pulverized coal channel. The ammonia distributor is provided with an ammonia distribution hole at least in the part inside the pulverized coal concentrator.
[0007] In a possible implementation, the inlet powder concentrator includes a powder concentrating portion and a powder concentrating portion arranged in sequence along the coal powder conveying direction; and / or, The pulverized coal concentrator comprises a pulverized coal airflow gradually contracting inlet, a pulverized coal airflow main body and a mixed gas gradually expanding outlet which are arranged in sequence along the pulverized coal conveying direction.
[0008] In a possible implementation, the inlet powder concentrator further includes a powder concentrating section of equal cross-section arranged between the powder concentrating section and the powder concentrating section; and / or, The areas of the minimum cross sections of the dense powder shrinking portion and the dense powder expanding portion are equal, and the areas of the minimum cross sections of the dense powder shrinking portion and the dense powder expanding portion are 50% to 90% of the cross-sectional area of the coal powder airflow channel; and / or, The inlet end area of the pulverized coal airflow tapering inlet is 50% to 80% of the cross-sectional area of the pulverized coal airflow channel; and / or, The outlet end area of the mixed gas gradually expanding outlet is 40% to 80% of the cross-sectional area of the coal powder airflow channel; and / or, The dense powder shrinking portion, the dense powder expanding portion and the pulverized coal channel are coaxially arranged; and / or, The maximum cross-sectional areas of the concentrated powder shrinking portion and the concentrated powder expanding portion are equal to the cross-sectional area of the coal powder channel.
[0009] In a possible implementation, the downstream end of the ammonia distributor protrudes outside the pulverized coal concentrator, or is sunken inside the pulverized coal concentrator, or is flush with the downstream end of the pulverized coal concentrator, and when the downstream end of the ammonia distributor protrudes outside the pulverized coal concentrator, the ammonia distribution hole is opened in the portion of the downstream end of the ammonia distributor protruding outside the pulverized coal concentrator; and / or, The downstream end of the pulverized coal channel is a terminal expansion, and the angle a between the side wall of the terminal expansion and the axis of the pulverized coal channel is 0° to 50°; and / or, The end face of the downstream end of the ammonia distributor and the end face of the downstream end of the pulverized coal concentrator are both located inside the pulverized coal channel, and the distance L4 between the end face of the downstream end of the pulverized coal concentrator and the end face of the downstream end of the pulverized coal channel is 100-500 mm.
[0010] In a possible implementation, the apertures of the ammonia distribution holes are equal or the apertures of at least two of the ammonia distribution holes are different; and / or, The included angle b between the center line of each ammonia distribution hole and the axis of the ammonia distributor is 45° to 90°; and / or, The ammonia distribution hole is a circular hole or a strip hole. When the ammonia distribution hole is a strip hole, the angle c between the extension direction of the strip hole and the axis of the ammonia distributor is 0° to 50°; and / or, The ammonia distributor comprises a section with a constant diameter and a raised pipe section, the diameter of the raised pipe section is larger than the diameter of the section with a constant diameter, and the ammonia distribution hole is provided on the raised pipe section.
[0011] In a possible implementation, the outlet end surface of the ammonia distributor is provided with air holes; and / or, The pulverized coal concentrator is provided with an ammonia-coal mixed gas distribution hole.
[0012] In a possible implementation, the apertures of the ammonia-coal mixed gas distribution holes are equal or the apertures of at least two of the ammonia-coal mixed gas distribution holes are unequal; and / or, The included angle between the center line of each of the ammonia-coal mixed gas distribution holes and the axis of the pulverized coal concentrator is 45° to 90°; and / or, The ammonia-coal mixed gas distribution hole is a circular hole or a strip hole. When the ammonia-coal mixed gas distribution hole is a strip hole, the angle between the extension direction of the strip hole and the axis of the pulverized coal concentrator is 0° to 50°; and / or, The distance L1 between the ammonia distribution hole at the upstream end and the ammonia-coal mixed gas distribution hole at the upstream end is 0-1000 mm; and / or, The distance L2 between the ammonia distribution hole at the downstream end and the ammonia-coal mixed gas distribution hole at the downstream end is 0-600 mm.
[0013] The ammonia-coal mixed combustion burner provided by the present application has an inlet end for spraying coal powder and air into the coal powder channel, and the gas-powder mixed airflow composed of coal powder and air changes the flow area at the inlet powder concentrator, so that the flow area of the gas-powder mixed airflow becomes smaller. Since the density of coal powder is significantly greater than the density of air, after the gas-powder mixed airflow leaves the inlet powder concentrator, the coal powder continues to flow forward in a straight line under the action of inertia, while the air diffuses outward after losing the constraint of the inlet powder concentrator, so that most of the coal powder and a small part of the air enter the coal powder concentrator, and a small part of the coal powder and most of the air enter the secondary channel between the coal powder concentrator and the coal powder channel. The ammonia distributor is used to introduce ammonia, and ammonia enters the coal powder concentrator through the ammonia distribution hole and mixes with the gas-powder mixed airflow, which makes the mixed airflow circulating in the coal powder concentrator have a higher concentration of coal powder and ammonia, while the mixed airflow circulating in the secondary channel has a lower concentration of coal powder.
[0014] Since the concentration of coal powder and ammonia in the coal powder concentrator is high and the air is low, the ammonia can react in an oxygen-deficient environment and no or less nitrogen oxides are produced. Even if nitrogen oxides are produced, they will be reduced to nitrogen through the volatile matter after the coal powder reaction and the unreacted residual ammonia, so the present application can reduce nitrogen oxide emissions.
[0015] A second aspect of the present application provides a boiler, comprising: The boiler body has a boiler tail flue; An ammonia-coal mixed combustion burner is an ammonia-coal mixed combustion burner as described in any one of the above items, and there are multiple ammonia-coal mixed combustion burners, and all of them are connected to the furnace of the boiler body; The ammonia evaporator uses the heat of the flue gas inside the tail flue of the boiler to evaporate the liquid ammonia in the ammonia evaporator into gaseous ammonia. The inlet end of the ammonia evaporator is connected to a liquid ammonia pipeline, and the outlet end is connected to a gaseous ammonia pipeline. The gaseous ammonia pipeline is connected to the ammonia distributor.
[0016] In a possible implementation, the ammonia evaporator is arranged inside the tail flue of the boiler; or, The ammonia evaporator is arranged outside the boiler tail flue, and the boiler tail flue draws out flue gas through a pipeline and acts on the ammonia evaporator.
[0017] In a possible implementation, a gaseous ammonia storage tank is connected in series to the gaseous ammonia pipeline; and / or, The gaseous ammonia pipeline and the liquid ammonia pipeline are provided with pressure sensors; and / or, A temperature sensor is provided on the gaseous ammonia pipeline; and / or, The liquid ammonia pipeline is provided with a liquid ammonia control valve group, and the liquid ammonia control valve group is used to adjust the flow rate and pressure of liquid ammonia entering the ammonia evaporator; and / or, The gaseous ammonia pipeline is provided with an ammonia control valve group, and the ammonia control valve group is used to adjust the flow rate and pressure of ammonia entering the ammonia-coal mixed combustion burner.
[0018] The boiler provided in the present application has all the technical effects of the above-mentioned ammonia-coal co-firing burner, and thus will not be described in detail herein. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0020] Figure 1 This is a schematic diagram of the structure of the ammonia-coal co-combustion burner disclosed in the embodiment of the present application; Figure 2 This is a schematic diagram of the structure of the ammonia-coal co-combustion burner disclosed in the embodiment of the present application; Figure 3 This is a schematic diagram of the structure of the ammonia distributor disclosed in the embodiment of the present application; Figure 4 A cross-sectional view of an ammonia distributor disclosed in another embodiment of the present application; Figure 5 This is a schematic structural diagram of an ammonia distributor disclosed in yet another embodiment of the present application; Figure 6 This is a schematic diagram of the structure of the outlet end face of the ammonia distributor disclosed in the embodiment of the present application. Figure 7 A schematic diagram of the structure of a boiler disclosed in an embodiment of the present application; Figure 8 This is a schematic diagram of the structure in which the ammonia evaporator of the boiler disclosed in the embodiment of the present application is located in the tail flue of the boiler.
[0021] The meanings of the reference numerals in the figures are as follows: 1-ammonia-coal mixed combustion burner; 10-ammonia distributor; 101-ammonia gas distribution hole; 102-raised pipe section; 103-gas inlet; 11-coal powder concentrator; 110-coal powder gas flow gradually contracting inlet; 111-mixed gas gradually expanding outlet; 112-ammonia-coal mixed gas distribution hole; 12-coal powder channel; 120-inlet end; 121-end expansion; 122-inlet powder concentrator; 2- ammonia evaporator; 20- heat exchange tube; 3-liquid ammonia flow control system; 301-liquid ammonia pipeline; 302-liquid ammonia control valve group; 303-gaseous ammonia pipeline; 304-gaseous ammonia storage tank; 305-pressure sensor; 306-temperature sensor; 307-ammonia control valve group; 4- Boiler tail flue; R0-coal powder air flow channel; R1-primary channel; R2-secondary channel; R3-tertiary channel. DETAILED DESCRIPTION
[0022] The core of this application is to provide an ammonia-coal co-combustion burner to reduce nitrogen oxide emissions under co-combustion conditions; Another core of the present application is to provide a boiler having the above-mentioned ammonia-coal co-firing burner.
[0023] The following describes the embodiments with reference to the accompanying drawings. In addition, the embodiments shown below do not limit the content of the application described in the claims. In addition, the entire content of the composition represented by the following embodiments is not limited to the solution required as the application described in the claims. It should be noted that, for the convenience of description, only the parts related to the relevant application are shown in the drawings. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other.
[0024] like Figure 1 and Figure 2 As shown, the ammonia-coal co-combustion burner disclosed in the embodiment of the present application includes a pulverized coal channel 12, a pulverized coal concentrator 11 and an ammonia distributor 10. Among them, an inlet powder concentrator 122 is provided in the pulverized coal channel 12, and the pulverized coal channel 12 is used to convey a gas-powder mixed airflow of pulverized coal and air. The inlet powder concentrator 122 is arranged as close as possible to the inlet end 120 of the pulverized coal channel 12, so that the gas-powder mixed airflow can quickly enter the inlet powder concentrator 122 after entering the pulverized coal channel 12 from the inlet end 120. The inlet powder concentrator 122 can reduce the flow area of the gas-powder mixed airflow, so that the gas-powder mixed airflow converges to the middle. The outlet end of the pulverized coal channel 12 is used to communicate with the furnace of the boiler.
[0025] The pulverized coal concentrator 11 is disposed in the pulverized coal channel 12 and is located downstream of the inlet pulverizer 122. It can be understood by those skilled in the art that the upstream and downstream mentioned herein are in terms of the flow direction of the airflow in the corresponding channel. The pulverized coal concentrator 11 can be coaxially arranged with the pulverized coal channel 12, or the pulverized coal concentrator 11 can be eccentrically arranged in the pulverized coal channel 12.
[0026] At least part of the structure of the ammonia distributor 10 is located in the pulverized coal channel 12, and passes through the inlet powder concentrator 122 and the pulverized coal concentrator 11. One end of the ammonia distributor 10 is a gas inlet 103, and the other end is a gas outlet. The end where the gas outlet is located can extend out of the pulverized coal concentrator 11 and is located in the pulverized coal channel 12, and the end where the gas inlet 103 is located can be located outside the pulverized coal channel 12 to facilitate communication with the ammonia supply pipeline. The ammonia distributor 10 can be coaxially arranged with the pulverized coal concentrator 11 and the pulverized coal channel 12, or the ammonia distributor 10 can be eccentrically arranged in the pulverized coal concentrator 11 and the pulverized coal channel 12.
[0027] A pulverized coal airflow channel R0 is formed between the ammonia distributor 10 and the pulverized coal channel 12, a primary channel R1 is formed between the ammonia distributor 10 and the pulverized coal concentrator 11, and a secondary channel R2 is formed between the pulverized coal concentrator 11 and the pulverized coal channel 12. The ammonia distributor 10 is provided with an ammonia distribution hole 101 at least in the part inside the pulverized coal concentrator 11, and the ammonia transported in the ammonia distributor 10 can enter the primary channel R1 through the ammonia distribution hole 101. The primary channel R1 is configured to transport a primary mixed gas (a mixed gas composed of pulverized coal, ammonia and air) to the pulverized coal channel 12. The secondary channel R2 is configured to transport a secondary mixed gas (which can be a mixed gas composed of pulverized coal and air, or a mixed gas composed of pulverized coal, ammonia and air).
[0028] In the ammonia-coal mixed combustion burner provided by the present application, the inlet end of the pulverized coal channel 12 is used to inject pulverized coal and air, and the gas-pulverized mixed airflow composed of pulverized coal and air changes the flow area at the inlet powder concentrator 122, so that the flow area of the gas-pulverized mixed airflow becomes smaller. Since the density of pulverized coal is significantly greater than the density of air, after the gas-pulverized mixed airflow leaves the inlet powder concentrator 122, the pulverized coal continues to flow forward in a straight line under the action of inertia, while the air diffuses outward after losing the constraint of the inlet powder concentrator 122, so that most of the pulverized coal and a small part of the air enter the pulverized coal concentrator 11 (that is, the primary channel R1), and a small part of the pulverized coal and most of the air enter the secondary channel R2 between the pulverized coal concentrator 11 and the pulverized coal channel 12. The ammonia distributor 10 is used to introduce ammonia, which enters the coal powder concentrator 11 through the ammonia distribution hole 101 and mixes with the gas-powder mixed airflow. This makes the mixed airflow circulating in the coal powder concentrator 11 have a higher coal powder and ammonia concentration, while the mixed airflow circulating in the secondary channel R2 has a lower coal powder concentration.
[0029] Since the concentration of coal powder and ammonia in the coal powder concentrator 11 is high and the air is low, the ammonia can react in an oxygen-deficient environment, and no or less nitrogen oxides are produced. Even if nitrogen oxides are produced, they will be reduced to nitrogen through the volatile matter after the coal powder reaction and the unreacted residual ammonia, so the present application can reduce nitrogen oxide emissions.
[0030] In addition, the embodiment of the present application changes the mixing method of ammonia and gas-powder mixed airflow from point mixing to surface mixing along the flow direction of the airflow, and the gradual mixing method from the ammonia distributor 10 located in the center of the burner to the coal powder concentrator 11 and the coal powder channel 12 on the outside can not only enhance the mixing uniformity, but also reduce the occupied space of the ammonia-coal co-combustion burner and reduce production costs.
[0031] In a specific embodiment of the present application, the inlet powder concentrator 122 includes a powder concentrating portion and a powder concentrating portion arranged in sequence along the coal powder conveying direction. The powder concentrating portion is upstream of the airflow conveying direction, and the powder concentrating portion is downstream of the airflow conveying direction. Concentrating means that the flow area gradually decreases as the airflow is conveyed downstream, while expanding means that the flow area gradually expands as the airflow is conveyed downstream.
[0032] After the gas-powder mixed air flow composed of coal powder and air enters through the inlet end 120 of the coal powder channel 12, it will first enter the concentrated powder shrinking part, and utilize the characteristic that the flow area of the concentrated powder shrinking part gradually shrinks, so that the gas-powder mixed air flow converges to the middle. After converging in the middle, the gas-powder mixed air flow enters the concentrated powder expanding part, and utilizes the characteristic that the flow area of the concentrated powder expanding part gradually expands, so that the gas with lower density in the gas-powder mixed air flow diffuses outward as the flow area expands, while the coal powder with higher density continues to remain in the middle convergent state and flows downstream under the action of inertia, so that more coal powder enters the coal powder concentrator 11, maintaining a high coal powder concentration in the coal powder concentrator 11.
[0033] In a specific embodiment of the present application, the pulverized coal concentrator 11 includes a pulverized coal gas flow gradually contracting inlet 110, a pulverized coal gas flow main body, and a mixed gas gradually expanding outlet 111 arranged in sequence along the pulverized coal conveying direction. The pulverized coal gas flow gradually contracting inlet 110 is upstream of the air flow conveying direction, the mixed gas gradually expanding outlet 111 is downstream of the air flow conveying direction, and the pulverized coal gas flow main body is located between the pulverized coal gas flow gradually contracting inlet 110 and the mixed gas gradually expanding outlet 111. Gradual contraction means that as the air flow is conveyed downstream, the flow area gradually decreases, while gradual expansion means that as the air flow is conveyed downstream, the flow area gradually increases. It should be noted that the flow area of the pulverized coal gas flow main body may remain unchanged.
[0034] In a specific embodiment of the present application, the inlet powder concentrator 122 may also include a concentrated powder equal cross-section portion arranged between the concentrated powder constriction portion and the concentrated powder expansion portion, the cross-sectional area of the concentrated powder equal cross-section portion remains unchanged, and is used to connect the concentrated powder constriction portion and the concentrated powder expansion portion to achieve the transition from the concentrated powder constriction portion to the concentrated powder expansion portion. The cross-sectional area of the concentrated powder equal cross-section portion may be equal to the minimum cross-sectional area of the concentrated powder constriction portion and the concentrated powder expansion portion. Taking the case that the cross-section of the inlet powder concentrator 122 is circular, the diameter of the concentrated powder equal cross-section portion is equal to the diameter of the small diameter end of the concentrated powder constriction portion and the concentrated powder expansion portion, and is correspondingly connected to the small diameter end of the concentrated powder constriction portion and the concentrated powder expansion portion.
[0035] The concentrated powder constriction part, the concentrated powder expansion part and the pulverized coal channel 12 are coaxially arranged, that is, the inlet powder concentrator 122 is coaxially arranged with the pulverized coal channel 12, and the maximum cross-sectional area of the concentrated powder constriction part and the concentrated powder expansion part is equal to the cross-sectional area of the pulverized coal channel 12. That is, the projections of the maximum cross-sectional areas of the concentrated powder constriction part and the concentrated powder expansion part on the pulverized coal channel 12 coincide. When the cross-section of the pulverized coal channel 12 is circular, the large diameter end of the concentrated powder expansion part of the concentrated powder constriction part is equal to the inner diameter of the pulverized coal channel 12, and the outer side wall of the large diameter end of the concentrated powder expansion part of the concentrated powder constriction part is sealed against the inner wall of the pulverized coal channel 12, so that the gas-powder mixed airflow entering from the inlet end 120 of the pulverized coal channel 12 all enters the inlet powder concentrator 122 for convergence, so as to increase the concentration of the pulverized coal converged to the middle.
[0036] In a specific embodiment of the present application, the areas of the minimum cross sections of the concentrated powder necking portion and the concentrated powder expanding portion are equal, and the areas of the minimum cross sections of the concentrated powder necking portion and the concentrated powder expanding portion are 50% to 90% of the cross-sectional area of the coal powder airflow channel R0. It should be noted that the cross-sectional area of the coal powder airflow channel R0 is the difference between the flow area of the coal powder channel 12 and the external contour area of the ammonia distributor 10. If the areas of the minimum cross sections of the concentrated powder necking portion and the concentrated powder expanding portion are designed to be smaller, the airflow resistance will be larger, affecting the transportation of the gas-powder mixed airflow; if the areas of the minimum cross sections of the concentrated powder necking portion and the concentrated powder expanding portion are designed to be larger, the concentration effect of the coal powder will be reduced. In this embodiment, the areas of the minimum cross sections of the concentrated powder necking portion and the concentrated powder expanding portion are designed to be 50% to 90% of the cross-sectional area of the coal powder airflow channel R0, which can take into account both the flow resistance and the concentration effect.
[0037] In a specific embodiment of the present application, the inlet end area of the coal powder airflow gradually contracting inlet 110 (the cross-sectional area of the large end of the coal powder airflow gradually contracting inlet 110) is 50% to 80% of the cross-sectional area of the coal powder airflow channel R0. If the inlet end area of the coal powder airflow gradually contracting inlet 110 is designed to be smaller, the amount of coal powder entering will be less, which is not conducive to increasing the coal powder concentration; if the inlet end area of the coal powder airflow gradually contracting inlet 110 is designed to be larger, more air will enter, which is not conducive to the concentration of coal powder. In this embodiment, the inlet end area of the coal powder airflow gradually contracting inlet 110 is designed to be 50% to 80% of the cross-sectional area of the coal powder airflow channel R0, which can obtain a better coal powder concentration effect.
[0038] The outlet end area of the mixed gas gradually expanding outlet 111 (the cross-sectional area of the large end of the mixed gas gradually expanding outlet 111) is 40% to 80% of the cross-sectional area of the coal powder airflow channel R0. If the outlet end area of the mixed gas gradually expanding outlet 111 is designed to be smaller, the airflow resistance in the primary channel R1 will be larger; if the outlet end area of the mixed gas gradually expanding outlet 111 is designed to be larger, the flow area of the outlet end of the secondary channel R2 will be smaller, resulting in a larger airflow resistance in the secondary channel R2. In this embodiment, the outlet end area of the mixed gas gradually expanding outlet 111 is 40% to 80% of the cross-sectional area of the coal powder airflow channel R0, which can balance the flow resistance of the primary channel R1 and the secondary channel R2.
[0039] In a specific embodiment of the present application, the downstream end of the ammonia distributor 10 extends out of the pulverized coal concentrator 11, and the portion of the downstream end of the ammonia distributor 10 extending out of the pulverized coal concentrator 11 is provided with an ammonia distribution hole 101. It should be noted that the portion of the downstream end of the ammonia distributor 10 extending out of the pulverized coal concentrator 11 may not be provided with an ammonia distribution hole 101. The ammonia distribution hole 101 located outside the pulverized coal concentrator 11 can release the ammonia delivered by the ammonia distributor 10 directly into the tertiary channel R3. The tertiary channel R3 is formed between the portion of the downstream end of the ammonia distributor 10 extending out of the pulverized coal concentrator 11 and the pulverized coal channel 12. The tertiary channel R3 is configured to deliver the tertiary mixed gas to the pulverized coal channel 12 and the boiler (the gaseous ammonia delivered by the ammonia distribution hole 101, the primary mixed gas delivered by the mixed gas gradually expanding outlet 111, and the secondary mixed gas delivered by the secondary channel R2 are mixed in the tertiary channel R3 to form a tertiary mixed gas).
[0040] It is understood by those skilled in the art that the end surface of the downstream end of the ammonia distributor 10 may also be designed to be flush with the end surface of the downstream end of the coal powder concentrator 11, and the downstream end of the ammonia distributor 10 may also be designed to be recessed in the coal powder concentrator 11 (e.g. Figure 2 As shown). The end surface of the downstream end of the ammonia distributor 10 and the end surface of the downstream end of the pulverized coal concentrator 11 may both be located inside the pulverized coal channel 12, and the distance L4 between the end surface of the downstream end of the pulverized coal concentrator 11 and the end surface of the downstream end of the pulverized coal channel 12 is 100-500 mm. The specific value of the distance L4 can be designed by those skilled in the art according to actual needs.
[0041] like Figure 6 As shown, the outlet end surface of the ammonia distributor 10 may also be provided with air holes.
[0042] In a specific embodiment of the present application, the downstream end of the pulverized coal channel 12 is a terminal flare 121, the flow area of the terminal flare 121 gradually expands along the flow direction of the airflow, and the angle a between the side wall of the terminal flare 121 and the axis of the pulverized coal channel 12 is 0°~50°. In this embodiment, the outlet end of the pulverized coal channel 12 is designed as a flare structure, which can not only suck in high-temperature reflux flue gas, but also use inertia to concentrate the pulverized coal, so that the center has a higher pulverized coal concentration and the periphery has a high-low concentration graded airflow with a lower pulverized coal concentration.
[0043] In a specific embodiment of the present application, the apertures of each ammonia distribution hole 101 can be designed to be equal, or the apertures of at least two of the ammonia distribution holes 101 can be designed to be unequal. It should be noted that the ammonia distribution holes 101 can be designed in multiple rows along the extension direction of the ammonia distributor 10, and each row can be provided with multiple holes in the circumferential direction around the ammonia distributor 10 to improve the uniformity of mixing ammonia with coal powder and air. The apertures of each row of ammonia distribution holes 101 can be designed to be the same; the apertures of the ammonia distribution holes 101 in odd rows can also be designed to be the same, the apertures of the ammonia distribution holes 101 in even rows can be designed to be the same, and the apertures of the ammonia distribution holes 101 in odd rows and even rows can be designed to be different. Those skilled in the art can design the apertures of the ammonia distribution holes 101 according to needs.
[0044] like Figure 4 As shown, the angle b between the center line of each ammonia distribution hole 101 and the axis of the ammonia distributor 10 is 45°~90°. That is, the ammonia distribution hole 101 is inclined toward the direction of airflow delivery, so that there is less resistance. Of course, the ammonia distribution hole 101 can also be inclined in the direction opposite to the airflow delivery direction. Such a setting can have a more intense mixing effect (that is, the ammonia flowing into the primary channel R1 through the ammonia distribution hole 101 is mixed with the gas-powder mixed airflow transported in the primary channel R1). It should be noted that the center line of each ammonia distribution hole 101 and the axis of the ammonia distributor 10 can also be set to be perpendicular, and a more intense mixing effect can also be obtained.
[0045] The ammonia distribution hole 101 can be a circular hole or a Figure 5 The strip-shaped holes shown can of course be holes of other shapes, and this embodiment does not limit the shape of the ammonia distribution hole 101. When the ammonia distribution hole 101 is a strip-shaped hole, the angle c between the extension direction of the strip-shaped hole and the axis of the ammonia distributor 10 is 0°~50°. Such a setting can make the ammonia have a swirl effect, a good mixing effect, and is conducive to entraining the high-concentration gas-powder mixed airflow in the primary channel R1.
[0046] like Figure 4As shown, the ammonia distributor 10 includes an equal diameter section and a raised pipe section 102, the diameter of the raised pipe section 102 is larger than the diameter of the equal diameter section, and an ammonia distribution hole 101 is opened on the raised pipe section 102. The raised pipe section 102 can be arranged inside the pulverized coal concentrator 11, and close to the position of the mixed gas gradually expanding outlet 111. The raised pipe section 102 can mainly form a layer of concentrated pulverized coal layer on the outer ring of the primary channel R1, wrapping the ammonia gas sprayed from the ammonia distribution hole 101 on the outlet side (that is, the ammonia distribution hole 101 located on the part of the ammonia distributor 10 located outside the pulverized coal concentrator 11), forming an airflow structure with high ammonia concentration and high pulverized coal concentration in the center.
[0047] In a specific embodiment of the present application, an ammonia-coal mixed gas distribution hole 112 is provided on the pulverized coal concentrator 11. The primary mixed gas transported in the primary channel R1 can flow into the secondary channel R2 through the ammonia-coal mixed gas distribution hole 112 provided on the pulverized coal concentrator 11, and mix with the gas-powder mixed fluid with a low pulverized coal concentration transported in the secondary channel R2 to form a secondary mixed gas.
[0048] Since the primary channel R1 conveys a primary mixed gas with a high concentration and a high internal pressure, and the secondary channel R2 conveys a gas-powder mixed gas with a low concentration, there is a large pressure difference between the two, which easily causes deformation of the pulverized coal concentrator 11. In this embodiment, by providing an ammonia-coal mixed gas distribution hole 112 on the pulverized coal concentrator 11, a part of the primary mixed gas is allowed to enter the secondary channel R2, so as to maintain the pressure balance inside and outside the pulverized coal concentrator 11.
[0049] In a specific embodiment of the present application, the apertures of each ammonia-coal mixed gas distribution hole 112 can be designed to be equal, or the apertures of at least two of the ammonia-coal mixed gas distribution holes 112 can be designed to be unequal. It should be noted that the ammonia-coal mixed gas distribution holes 112 can be designed in multiple rows along the extension direction of the coal powder concentrator 11, and each row can be provided with multiple holes in the circumferential direction around the coal powder concentrator 11 to improve the mixing uniformity and obtain a uniform decompression effect. The apertures of each row of ammonia-coal mixed gas distribution holes 112 can be designed to be the same; the apertures of the ammonia-coal mixed gas distribution holes 112 in odd-numbered rows can also be designed to be the same, the apertures of the ammonia-coal mixed gas distribution holes 112 in even-numbered rows can be designed to be the same, and the apertures of the ammonia-coal mixed gas distribution holes 112 in odd-numbered rows and even-numbered rows can be designed to be different. Those skilled in the art can design the apertures of the ammonia-coal mixed gas distribution holes 112 according to needs.
[0050] The angle between the center line of each ammonia-coal mixed gas distribution hole 112 and the axis of the pulverized coal concentrator 11 is 45°~90°. That is, the ammonia-coal mixed gas distribution hole 112 is inclined toward the direction of airflow delivery, so that it can have smaller resistance. Of course, the ammonia-coal mixed gas distribution hole 112 can also be inclined in the direction opposite to the airflow delivery direction. Such a setting can have a more intense mixing effect (that is, the primary mixed gas delivered through the primary channel R1 is mixed with the low-concentration gas-powder mixed gas delivered in the secondary channel R2 to obtain a secondary mixed gas). It should be noted that the center line of each ammonia-coal mixed gas distribution hole 112 can also be set to be perpendicular to the axis of the pulverized coal concentrator 11, and a more intense mixing effect can also be obtained.
[0051] The ammonia-coal mixed gas distribution hole 112 may be a circular hole or a strip hole, or of course, a hole of other shapes. This embodiment does not limit the shape of the ammonia-coal mixed gas distribution hole 112. When the ammonia-coal mixed gas distribution hole 112 is a strip hole, the angle between the extension direction of the strip hole and the axis of the pulverized coal concentrator 11 is 0° to 50°. Such a setting can make the primary mixed gas have a swirl effect, a good mixing effect, and is conducive to entraining the low-concentration gas-powder mixed gas flow in the secondary channel R2.
[0052] In a specific embodiment of the present application, the distance L1 between the upstream ammonia distribution hole 101 and the upstream ammonia-coal mixed gas distribution hole 112 is 0-1000 mm. L1 is mainly considered to allow ammonia to mix slowly along the airflow to reduce disturbance during mixing, that is, ammonia begins to mix with the airflow in the primary channel R1 before the ammonia-coal mixed gas distribution hole 112, so that there is less disturbance.
[0053] The distance L2 between the downstream ammonia distribution hole 101 and the downstream ammonia-coal mixed gas distribution hole 112 is 0-600 mm. That is, a part of the ammonia is sprayed into the primary channel R1, and the other part (generally the part within the range of L2) is sprayed into the tertiary channel R3. Since the ammonia is not sprayed into the primary channel R1, it is beneficial to reduce the resistance of the primary channel R1 and balance the resistance of the primary channel R1 and the secondary channel R2.
[0054] It should be noted that, in this embodiment, the proportional relationship between the different cross-sectional areas disclosed above refers to the flow area, that is, the area does not include the wall thickness of the channel.
[0055] like Figure 7 and Figure 8 As shown, the boiler disclosed in the embodiment of the present application includes a boiler body, an ammonia-coal co-firing burner 1, an ammonia evaporator 2 and a liquid ammonia flow control system 3. Each boiler can be provided with multiple ammonia evaporators 2 and matching liquid ammonia flow control systems 3.
[0056] The boiler body has a boiler tail flue 4, and the ammonia-coal mixed combustion burner 1 is the ammonia-coal mixed combustion burner 1 disclosed in the above embodiment, and there are multiple ammonia-coal mixed combustion burners 1, which are all connected to the furnace of the boiler body. Since the boiler disclosed in the embodiment of the present application has the ammonia-coal mixed combustion burner 1 disclosed in the above embodiment, it has all the technical effects of the above ammonia-coal mixed combustion burner 1, which will not be repeated here.
[0057] The heat of the flue gas inside the boiler tail flue 4 is used to evaporate the liquid ammonia in the ammonia evaporator 2 into gaseous ammonia. Specifically, the ammonia evaporator 2 can be directly arranged inside the boiler tail flue 4, or can be arranged outside the boiler tail flue 4. The boiler tail flue 4 leads the flue gas through a pipeline and acts on the ammonia evaporator 2. As long as the high-temperature flue gas can flow through the ammonia evaporator 2 to heat the liquid ammonia flowing in the heat exchange tube 20 of the ammonia evaporator 2, it will be sufficient.
[0058] The liquid ammonia flow control system 3 includes a liquid ammonia pipeline 301 and a gaseous ammonia pipeline 303, wherein the liquid ammonia pipeline 301 is connected to the inlet end of the ammonia evaporator 2, the gaseous ammonia pipeline 303 is connected to the outlet end of the ammonia evaporator 2, and the gaseous ammonia pipeline 303 is also connected to the ammonia distributor 10. The liquid ammonia supply device is connected to the liquid ammonia pipeline 301, and is used to supply liquid ammonia to the ammonia evaporator 2 through the liquid ammonia pipeline 301. The liquid ammonia exchanges heat with the high-temperature flue gas in the ammonia evaporator 2 and is gasified into ammonia gas. The ammonia gas enters the ammonia distributor 10 through the gaseous ammonia pipeline 303.
[0059] In order to ensure that the flow rate of the gaseous ammonia pipeline 303 supplied to the ammonia distributor 10 is relatively stable, in a specific embodiment of the present application, the liquid ammonia flow control system 3 may also include a gaseous ammonia storage tank 304 arranged in series on the gaseous ammonia pipeline 303. The ammonia gas vaporized by the ammonia evaporator 2 can be temporarily stored in the gaseous ammonia storage tank 304 to prevent excessive ammonia gas from being supplied to the ammonia distributor 10, resulting in excessive ammonia concentration.
[0060] In a specific embodiment of the present application, the liquid ammonia flow control system 3 may further include a pressure sensor 305 provided on the gaseous ammonia pipeline 303 and the liquid ammonia pipeline 301. The pressure sensor 305 may respectively detect the pressure of ammonia gas in the gaseous ammonia pipeline 303 and the pressure of liquid ammonia in the liquid ammonia pipeline 301. When the pressure exceeds the set pressure, the supply flow of the liquid ammonia supply device may be reduced to prevent damage to the equipment caused by excessive pressure.
[0061] In a specific embodiment of the present application, the liquid ammonia flow control system 3 may further include a temperature sensor 306 disposed on the gaseous ammonia pipeline 303, and the temperature sensor 306 is used to detect the temperature value of the ammonia gas. The liquid ammonia flow control system 3 may further include a liquid ammonia control valve group 302 disposed on the liquid ammonia pipeline 301, and the liquid ammonia control valve group 302 is used to adjust the flow rate and pressure of the liquid ammonia entering the ammonia evaporator 2. The liquid ammonia control valve group 302 may be manually controlled or automatically controlled. When automatically controlled, when the pressure value detected by the pressure sensor 305 on the liquid ammonia pipeline 301 exceeds the preset pressure, the liquid ammonia flow rate and pressure may be reduced by the liquid ammonia control valve group 302.
[0062] In a specific embodiment of the present application, the liquid ammonia flow control system 3 may also include an ammonia control valve group 307 provided on the gaseous ammonia pipeline 303, and the ammonia control valve group 307 is used to adjust the ammonia flow and pressure entering the ammonia-coal mixed combustion burner 1. The ammonia control valve group 307 can be manually controlled or automatically controlled. During automatic control, when the pressure value detected by the pressure sensor 305 on the gaseous ammonia pipeline 303 exceeds the preset pressure, the liquid ammonia flow and pressure can be reduced by the ammonia control valve group 307. It should be noted that the ammonia control valve group 307 can also be controlled by other parameters, and is not limited to the pressure value on the gaseous ammonia pipeline 303. Those skilled in the art can design the conditions for automatic control according to needs.
[0063] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.
[0064] 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.
[0065] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0066] Specific examples are used herein to illustrate the principles and implementation methods of the present application, and the description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.
Claims
1. An ammonia-coal co-combustion burner, characterized in that: include: A pulverized coal channel (12), wherein an inlet pulverized coal concentrator (122) is provided in the pulverized coal channel (12); A coal powder concentrator (11) is arranged in the coal powder channel (12) and is located downstream of the inlet powder concentrator (122); An ammonia distributor (10) at least part of which is located in the pulverized coal channel (12) and passes through the inlet pulverizer concentrator (122) and the pulverized coal concentrator (11); a pulverized coal airflow channel (R0) is formed between the ammonia distributor (10) and the pulverized coal channel (12); a primary channel (R1) is formed between the ammonia distributor (10) and the pulverized coal concentrator (11); a secondary channel (R2) is formed between the pulverized coal concentrator (11) and the pulverized coal channel (12); and an ammonia distribution hole (101) is provided in at least a portion of the ammonia distributor (10) inside the pulverized coal concentrator (11).
2. The ammonia-coal co-firing burner according to claim 1, characterized in that: The inlet powder concentrator (122) comprises a powder concentrating portion and a powder concentrating portion which are arranged in sequence along the coal powder conveying direction; and / or, The pulverized coal concentrator (11) comprises a pulverized coal airflow gradually contracting inlet (110), a pulverized coal airflow main body, and a mixed gas gradually expanding outlet (111) which are arranged in sequence along the pulverized coal conveying direction.
3. The ammonia-coal co-firing burner according to claim 2, characterized in that: The inlet powder concentrator (122) further comprises a powder concentrating equal-section portion arranged between the powder concentrating constriction portion and the powder concentrating expanding portion; and / or, The areas of the minimum cross sections of the dense powder shrinking portion and the dense powder expanding portion are equal, and the areas of the minimum cross sections of the dense powder shrinking portion and the dense powder expanding portion are 50% to 90% of the cross-sectional area of the pulverized coal airflow channel (R0); and / or, The inlet end area of the pulverized coal airflow tapered inlet (110) is 50% to 80% of the cross-sectional area of the pulverized coal airflow channel (R0); and / or, The outlet end area of the mixed gas gradually diverging outlet (111) is 40% to 80% of the cross-sectional area of the pulverized coal airflow channel (R0); and / or, The dense powder shrinking portion, the dense powder expanding portion and the pulverized coal channel (12) are coaxially arranged; and / or, The maximum cross-sectional areas of the concentrated powder constriction portion and the concentrated powder expansion portion are equal to the cross-sectional area of the coal powder channel (12).
4. The ammonia-coal co-firing burner according to claim 1, characterized in that: The downstream end of the ammonia distributor (10) protrudes outside the pulverized coal concentrator (11), or is sunken inside the pulverized coal concentrator (11), or is flush with the downstream end of the pulverized coal concentrator (11), and when the downstream end of the ammonia distributor (10) protrudes outside the pulverized coal concentrator (11), the ammonia distribution hole (101) is provided in the portion of the downstream end of the ammonia distributor (10) protruding outside the pulverized coal concentrator (11); and / or, The downstream end of the pulverized coal channel (12) is a terminal flare (121), and the angle a between the side wall of the terminal flare (121) and the axis of the pulverized coal channel (12) is 0° to 50°; and / or, The end surface of the downstream end of the ammonia distributor (10) and the end surface of the downstream end of the pulverized coal concentrator (11) are both located inside the pulverized coal channel (12), and a distance L4 between the end surface of the downstream end of the pulverized coal concentrator (11) and the end surface of the downstream end of the pulverized coal channel (12) is 100-500 mm.
5. The ammonia-coal co-firing burner according to any one of claims 1 to 4, characterized in that: The apertures of the ammonia distribution holes (101) are all equal, or the apertures of at least two of the ammonia distribution holes (101) are unequal; and / or, The included angle b between the center line of each ammonia distribution hole (101) and the axis of the ammonia distributor (10) is 45° to 90°; and / or, The ammonia distribution hole (101) is a circular hole or a strip hole. When the ammonia distribution hole (101) is a strip hole, the angle c between the extension direction of the strip hole and the axis of the ammonia distributor (10) is 0° to 50°; and / or, The ammonia distributor (10) comprises a section of equal diameter and a raised pipe section (102); the diameter of the raised pipe section (102) is greater than the diameter of the section of equal diameter, and the ammonia distribution hole (101) is provided on the raised pipe section (102).
6. The ammonia-coal co-firing burner according to any one of claims 1 to 4, characterized in that: The outlet end surface of the ammonia distributor (10) is provided with air holes; and / or, The pulverized coal concentrator (11) is provided with an ammonia-coal mixed gas distribution hole (112).
7. The ammonia-coal co-firing burner according to claim 6, characterized in that: The apertures of the ammonia-coal mixed gas distribution holes (112) are all equal, or the apertures of at least two of the ammonia-coal mixed gas distribution holes (112) are unequal; and / or, The included angle between the center line of each of the ammonia-coal mixed gas distribution holes (112) and the axis of the pulverized coal concentrator (11) is 45° to 90°; and / or, The ammonia-coal mixed gas distribution hole (112) is a circular hole or a strip hole. When the ammonia-coal mixed gas distribution hole (112) is a strip hole, the angle between the extension direction of the strip hole and the axis of the pulverized coal concentrator (11) is 0° to 50°; and / or, The distance L1 between the ammonia distribution hole (101) at the upstream end and the ammonia-coal mixed gas distribution hole (112) at the upstream end is 0-1000 mm; and / or, The distance L2 between the ammonia distribution hole (101) at the downstream end and the ammonia-coal mixed gas distribution hole (112) at the downstream end is 0-600 mm.
8. A boiler, characterized in that: include: A boiler body having a boiler tail flue (4); An ammonia-coal mixed combustion burner (1), which is the ammonia-coal mixed combustion burner (1) according to any one of claims 1 to 7, and there are a plurality of the ammonia-coal mixed combustion burners (1), all of which are connected to the furnace of the boiler body; The ammonia evaporator (2) uses the heat of the flue gas inside the boiler tail flue (4) to evaporate the liquid ammonia in the ammonia evaporator (2) into gaseous ammonia. The inlet end of the ammonia evaporator (2) is connected to a liquid ammonia pipeline (301), and the outlet end is connected to a gaseous ammonia pipeline (303). The gaseous ammonia pipeline (303) is connected to the ammonia distributor (10).
9. The boiler according to claim 8, characterized in that The ammonia evaporator (2) is arranged inside the boiler tail flue (4); or, The ammonia evaporator (2) is arranged outside the boiler tail flue (4), and the boiler tail flue (4) draws out flue gas through a pipeline and acts on the ammonia evaporator (2).
10. The boiler according to claim 8, characterized in that The gaseous ammonia pipeline (303) is connected in series with a gaseous ammonia storage tank (304); and / or, The gaseous ammonia pipeline (303) and the liquid ammonia pipeline (301) are provided with pressure sensors (305); and / or, The gaseous ammonia pipeline (303) is provided with a temperature sensor (306); and / or, The liquid ammonia pipeline (301) is provided with a liquid ammonia control valve group (302), and the liquid ammonia control valve group (302) is used to adjust the flow rate and pressure of the liquid ammonia entering the ammonia evaporator (2); and / or, The gaseous ammonia pipeline (303) is provided with an ammonia control valve group (307), and the ammonia control valve group (307) is used to adjust the flow rate and pressure of ammonia entering the ammonia-coal mixed combustion burner (1).