CN117571913A - Experimental ammonia coal combustion test system and combustion control method for industrial boiler - Google Patents
Experimental ammonia coal combustion test system and combustion control method for industrial boiler Download PDFInfo
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- CN117571913A CN117571913A CN202311297462.XA CN202311297462A CN117571913A CN 117571913 A CN117571913 A CN 117571913A CN 202311297462 A CN202311297462 A CN 202311297462A CN 117571913 A CN117571913 A CN 117571913A
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 350
- 239000003245 coal Substances 0.000 title claims abstract description 227
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 222
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 164
- 238000012360 testing method Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 23
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 103
- 239000000446 fuel Substances 0.000 claims abstract description 70
- 238000002156 mixing Methods 0.000 claims abstract description 56
- 239000002245 particle Substances 0.000 claims abstract description 19
- 238000009826 distribution Methods 0.000 claims abstract description 10
- 239000002817 coal dust Substances 0.000 claims description 26
- 239000000498 cooling water Substances 0.000 claims description 16
- 238000007599 discharging Methods 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 9
- 239000000725 suspension Substances 0.000 claims description 6
- 239000007921 spray Substances 0.000 claims description 3
- 230000002093 peripheral effect Effects 0.000 claims description 2
- 239000000843 powder Substances 0.000 abstract description 16
- 239000007789 gas Substances 0.000 description 30
- 239000007800 oxidant agent Substances 0.000 description 18
- 230000001590 oxidative effect Effects 0.000 description 18
- 238000013461 design Methods 0.000 description 15
- 239000003344 environmental pollutant Substances 0.000 description 10
- 231100000719 pollutant Toxicity 0.000 description 10
- 230000006872 improvement Effects 0.000 description 8
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- 238000011105 stabilization Methods 0.000 description 4
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- 238000006243 chemical reaction Methods 0.000 description 3
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- 229910000831 Steel Inorganic materials 0.000 description 2
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- 239000000919 ceramic Substances 0.000 description 2
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- 229910000069 nitrogen hydride Inorganic materials 0.000 description 2
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- 239000000243 solution Substances 0.000 description 2
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- 238000003860 storage Methods 0.000 description 2
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- 238000005496 tempering Methods 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 1
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- 238000011088 calibration curve Methods 0.000 description 1
- 238000004939 coking Methods 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
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- 238000012840 feeding operation Methods 0.000 description 1
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- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/12—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using combustion
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D17/00—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel
- F23D17/005—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel gaseous or pulverulent fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
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- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
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Abstract
The invention discloses an experimental ammonia coal turbulent combustion test system for an industrial boiler, which comprises a combustion chamber, an ammonia coal burner, a coal powder feeding system and a feeding and distributing system, wherein the ammonia coal burner is arranged in the combustion chamber and comprises a combustion body, a central fuel pipe, a tangential feeding cavity and an axial feeding cavity, the circumferential wall of the tangential feeding cavity is provided with a tangential feeding port, the axis of the tangential feeding port is arranged along the tangential direction of the periphery of the tangential feeding cavity, and a rotational flow structure is arranged between the outlet end of a combustion cavity channel and the outlet end of the central fuel pipe; the pulverized coal feeding system is used for feeding pulverized coal; the feed gas distribution system comprises a methane supply assembly, an ammonia supply assembly and an air supply assembly, and has two feed modes of carrying flow and single particle, wherein each feed mode comprises four combustion control methods of axial/tangential direction and premixing/non-premixing. By changing the air inlet and mixing modes, convenience is provided for researching ammonia coal combustion flame and emission control under the condition of realizing a plurality of different combustion modes in a laboratory.
Description
Technical Field
The invention relates to the technical field of ammonia coal burners, in particular to an experimental-grade ammonia coal turbulent combustion test system and a combustion control method for an industrial boiler.
Background
At present, research on the ammonia-doped combustion of a power station boiler at home and abroad is just started, and the research is still very weak in the aspects of ammonia coal combustion basic theory, combustion technology and development and engineering application processes of an ammonia coal dedicated burner. The concrete steps are as follows: (1) The combustion basic theoretical research on the mixed combustion of ammonia-hydrocarbon fuel is mostly focused on the mixed combustion of ammonia and micromolecular gas fuel, but the mixed combustion behavior of ammonia and solid macromolecule hydrocarbon fuel such as coal is very lack of knowledge; (2) In the case of the ammonia-coal mixed combustion test, the research is only carried out on a few existing combustion devices with the level of several megawatts, and the NH is also required to be paid attention to in the development of an ammonia combustion system 3 The problems of corrosiveness, ammonia escape, ammonia leakage, NOx emission and the like, and no formed ammonia coal burner exists in the market at present, so that a specific design is needed, a laboratory-level ammonia coal burner specially designed for small-scale and small-scale research is gradually popularized to industrial application; (3) Low pollutant emission ammonia-doped coal for high concentration, high proportion ammonia-doped situations Powder burner optimization and hearth combustion strategies are rarely explored.
Ammonia fuel co-combustion presents a number of challenges such as difficulty in ammonia combustion ignition, poor flame stability, and high NOx emissions: combustion defect problem and NH 3 The low reactivity and hence the slow flame propagation speed, the narrow flammability range, are closely related, while pollutant emissions are mainly caused by the presence of N atoms in the fuel molecules (i.e. fuel-type NOx). Meanwhile, after macromolecular solid particles such as coal dust are added, the problems of safety and stability are brought to the blending combustion of the burner due to the complex composition of solid fuel, such as unsmooth feeding and uneven blending, coking and slagging of a hearth and the burner, corrosion of a heating surface and the like, and the service life of the burner is greatly influenced. In addition, in actual industrial combustion, most of the flame is turbulent flame, compared with laminar flame generated by a conventional laboratory-grade flat flame furnace, the turbulent flame has random appearance and shape, is free from floating and rigid, is also mixed with noise to a certain extent, and causes great trouble to combustion stability and experimental safety.
Disclosure of Invention
The invention aims to provide an experimental ammonia coal turbulent combustion test system and a combustion control method for an industrial boiler, which are used for solving one or more technical problems in the prior art and at least providing a beneficial selection or creation condition.
The technical scheme adopted for solving the technical problems is as follows:
the invention provides an experimental ammonia coal turbulent combustion test system for an industrial boiler, which comprises a combustion chamber, an ammonia coal burner, a coal powder feeding system and a feeding and distributing system, wherein the ammonia coal burner is arranged in the combustion chamber and comprises a combustion body and a central fuel pipe, the central fuel pipe penetrates through a combustion cavity channel, a tangential feed port is arranged on the peripheral wall of the tangential feed cavity, the axis of the tangential feed port is arranged along the tangential direction of the periphery of the tangential feed cavity, and a rotational flow structure is arranged between the outlet end of the combustion cavity channel and the outlet end of the central fuel pipe; the pulverized coal feeding system is used for feeding pulverized coal; the feed gas distribution system comprises a methane supply assembly, an ammonia gas supply assembly and an air supply assembly, wherein the air supply assembly is connected with an outlet of the pulverized coal feed system in a first mixing pipe section, the outlet of the first mixing pipe section is simultaneously communicated with a tangential feed inlet and an axial feed inlet, the air supply assembly is connected with an outlet of the methane supply assembly in a second mixing pipe section, the second mixing pipe section is communicated with the axial feed inlet, the outlets of the methane supply assembly and the ammonia gas supply assembly are connected with a third mixing pipe section, and the outlet of the third mixing pipe section is communicated with a central feed inlet.
The beneficial effects of the invention are as follows:
when multiple test combustion modes are needed, the premixed/non-premixed, axial/tangential combustion control method under the pulverized coal carrying flow and single-particle suspension gas circuit can be realized by changing the on-off of each pulverized coal feeding pipe and the on-off of each gas storage bottle gas, the flexible switching and test method design can be realized, the functions of adjusting the wide power ratio (0-20 kW) under different ammonia/coal mixing ratios, realizing the wide combustion limit, the variable swirl, the flexible fuel conversion, optimizing the low pollutant emission and the like under different ammonia coal mixing ratios can be effectively realized by utilizing different combustion organization strategies, and convenience is provided for researching ammonia coal combustion flames under multiple different combustion mode conditions in a laboratory.
As a further improvement of the technical scheme, the device further comprises a flow guide blunt body, wherein the flow guide blunt body comprises a nozzle part plugged at the outlet end of the central fuel pipe and a first back taper flow guide block arranged at the nozzle part, and the nozzle part is provided with a spray outlet;
still perhaps still include the closed blunt body, the closed blunt body includes the shutoff portion of center fuel pipe exit end and locates the second back taper guide block of shutoff portion.
The flow guiding blunt body can rapidly guide flame forming through the shape of the first inverted cone flow guiding block, promote flame propagation, and facilitate flame stabilization and reduce backfire; the other is a closed blunt body for closing the center fuel tube in a premix mode. The first inverted cone flow guide block and the second inverted cone flow guide block can automatically design the inclined angles of different flow patterns and angles according to the flow guide effect required by experimental conditions, so that researchers in a laboratory can conveniently explore the influence of different blunt body shapes and flow guide angles on the stability and emission characteristics of ammonia coal combustion flame, and the combustion technology is optimized.
As a further improvement of the above technical solution, the outer circumferential wall of the combustion body is provided with a cooling water channel in a circumferential direction. The cooling water channel is used for introducing circulating cooling water to cool the ammonia coal burner in real time, so that the ammonia coal burner is prevented from being in a superheated state for a long time, and the service life of the ammonia coal burner is prolonged.
As a further improvement of the above technical solution, the remote automatic ignition device further comprises a remote automatic ignition device, wherein the remote automatic ignition device comprises an igniter, the ignition end of the igniter is adjustable in the axial and radial directions relative to the outlet end of the combustion chamber channel, and the outlet end of the combustion chamber channel is positioned on the rotating path of the igniter.
The ignition end of the igniter is just overlapped with the axial direction of the ammonia coal burner, and the distance between the igniter and the top end of the ammonia coal burner is set, so that the electric arc of the lighter is ensured to be just aligned to the upper part of the fuel outlet, and the ignition is favorably realized. The remote control igniter can be used for igniting, the design is simple, the operation is convenient, and the safety and the reliability of laboratory operators are greatly improved.
As a further improvement of the above technical scheme, the combustion chamber comprises a combustion cover, the lower part of the combustion cover is cylindrical, and the upper part of the combustion cover is in a truncated cone shape with the diameter gradually reduced from bottom to top.
The cylindrical combustion cover can promote flame stabilization, so that the combustion is more sufficient, and the pollutant emission concentration is effectively reduced; the truncated cone shape can greatly limit flame lifting and prevent fire escape; meanwhile, the gas backflow at the total outlet of the ammonia coal burner is avoided, and the backfire is reduced; the limit of ammonia coal combustion can be widened to a certain extent, the structure of the burner can be protected, and the service life is prolonged.
As a further improvement of the technical scheme, the total outlet of the combustion body is provided with a pulverized coal particle suspension net. In the single-particle suspension mode, pulverized coal particles are suspended on a metal wire mesh in a combustion cover, and other air inlet modes are the same as those in the carrying flow mode and are used for directionally tracking the combustion state and characteristics of the single particles.
As a further improvement of the technical scheme, the pulverized coal feeding system comprises an ammonia coal mixer and a pulverized coal feeder, wherein a primary air inlet is formed in the upper end of the ammonia coal mixer, a mixing outlet is formed in the lower end of the ammonia coal mixer, and the pulverized coal feeder is used for conveying pulverized coal into the ammonia coal mixer.
The pulverized coal is automatically controlled, so that the pulverized coal is accurately fed.
As a further improvement of the above technical scheme, the pulverized coal feeding system further comprises a mounting frame, the ammonia coal mixer is provided with a mixing cavity in an inverted cone shape, the discharge end of the pulverized coal feeding pipe of the pulverized coal feeder is arranged on the air outlet path where the primary air inlet is located, a first vibrator is arranged between the pulverized coal feeding pipe and the ammonia coal mixer, the pulverized coal feeding pipe is arranged on the mounting frame through a plurality of second vibrators, and the pulverized coal feeding pipe is arranged on the mounting frame through a plurality of third vibrators.
By adding vibration with certain frequency and amplitude, the pulverized coal is enabled to be vibrated to be in a dispersed state at any time, and meanwhile, the pulverized coal adhered to the wall surface is vibrated down, so that powder feeding updating and continuity are promoted.
The invention provides a combustion control method, which adopts the experimental ammonia coal turbulent combustion test system facing an industrial boiler and comprises the following steps:
in the feed mode of the pulverized coal carrying stream, four combustion modes are included:
in the first premixing mode, air, coal dust, ammonia gas and auxiliary gas methane are introduced into a plurality of axial feed inlets;
a premixing mode II, namely, introducing primary air carrying pulverized coal into a tangential feed inlet, and introducing classified air, ammonia gas and methane into an axial feed inlet;
in the first non-premixing mode, air and coal dust are introduced into the axial feed inlet, and ammonia and methane are introduced into the central feed inlet;
in a second non-premixing mode, classifying air is introduced into the axial feed inlet, ammonia and methane are introduced into the central feed inlet, and primary air carrying pulverized coal is introduced into the tangential feed inlet;
in the single-particle suspended feeding mode, the pulverized coal feeding system is closed, the pulverized coal feeding system comprises four combustion modes, the other air inlet modes are the same as those in the carrying flow mode, and the pulverized coal is suspended outside the ammonia coal burner and is mixed with gas sprayed by the ammonia coal burner for combustion.
The turbulent combustion of ammonia coal can be realized in laboratory level research, and multiple combustion modes can be automatically switched according to requirements: the method comprises four mixing strategies of carrying flow and single-particle feeding, namely axial non-premixing, tangential non-premixing, axial pre-mixing and tangential premixing, and can achieve the purposes of combustion classification and flexible regulation of combustion tissues through conversion of different combustion modes.
As a further improvement of the technical scheme, when the first premixing mode and the second premixing mode are needed, the central discharging port is provided with a closed blunt body (at the moment, the central fuel pipe can be removed or not removed according to the requirement, and the effect is consistent); and when the first non-premixing mode and the second non-premixing mode are needed, the central discharge hole is provided with a diversion blunt body.
The closed blunt body and the flow guiding blunt body are switched to be favorable for better burning of the ammonia-coal mixed fuel in a premixing mode and a non-premixing mode, so that the flow direction of flame is guided, the flame stabilizing effect on turbulent flame is realized, and the flame oscillation and lifting behaviors are effectively slowed down.
Drawings
The invention is further described below with reference to the drawings and examples;
FIG. 1 is a schematic diagram of the overall construction of an experimental ammonia coal turbulent combustion test system and combustion control method for an industrial boiler constructed in accordance with an embodiment of the present invention;
FIG. 2 is an engineering drawing of the swirl vane portion of the ammonia coal burner of FIG. 1, wherein (a) is a top view of the swirl vane, (b) is A-A cross-sectional view of the swirl vane of (a), (c) is a front view of the swirl vane, and (d) is an isometric view of the swirl vane;
FIG. 3 is an engineering drawing of the central fuel tube portion of the ammonia coal combustion body of FIG. 1, wherein (a) is an isometric view of the central fuel tube and (b) is a front view of the central fuel tube;
FIG. 4 is a schematic cross-sectional view of a carrier flow axial non-premixed combustion mode constructed in accordance with one embodiment of the invention;
FIG. 5 is an enlarged partial schematic view of the portion D of the deflector body of FIG. 4;
FIG. 6 is a schematic cross-sectional structural view of a carrying flow axial premix combustion mode constructed in accordance with a second embodiment of the invention;
FIG. 7 is an enlarged partial schematic view of the portion C of the enclosed bluff body of FIG. 6;
FIG. 8 is a schematic cross-sectional view of a carrier flow tangential non-premixed combustion mode constructed in accordance with a third embodiment of the invention;
FIG. 9 is a schematic cross-sectional view of a carrier flow tangential premixed combustion mode constructed in accordance with a fourth embodiment of the invention;
FIG. 10 is a schematic diagram of a pulverized coal feed system constructed in accordance with an embodiment of the invention;
FIG. 11 is a servo motor feed rate calibration curve in a carrier flow mode constructed in accordance with an embodiment of the invention;
FIG. 12 is a schematic view of a combustion chamber and remote auto-ignition device constructed in accordance with an embodiment of the invention.
Reference numerals:
the ammonia coal burner 100, the top discharging cavity 101, the tangential feeding cavity 102, the axial feeding cavity 103, the total outlet 104, the tangential feeding port 105, the axial feeding port 106, the sealing pipe cap 107, the combustion body 110, the central fuel pipe 120, the central feeding port 121, the central discharging port 122, the porous air guiding structure 130, the flow guiding blunt body 140, the nozzle portion 141, the ejection port 1411, the first back taper flow guiding block 142, the closed blunt body 150, the blocking portion 151, the second back taper flow guiding block 152, the cooling water channel 160, the cooling water inlet 161, the cooling water outlet 162;
the pulverized coal feeding system 200, a primary air path 201, a grading air path 202, an ammonia-coal mixer 210, a primary air inlet 211, a mixing outlet 212, a pulverized coal feeder 220, a pulverized coal feeding pipe 221, a mounting frame 230, a first vibrator 240a, a second vibrator 240b, a third vibrator 240c, a stepping cylinder feeder 250, a remote automatic ignition device 300, a T-shaped bracket lifting steering control 310, a steering T-shaped bracket 320, an igniter 330 and a spiral coil 340;
The gas supply and distribution system 400, the air cylinder 410, the ammonia gas cylinder 420, the methane cylinder 430, the first mixing pipe section 440, the second mixing pipe section 450, the third mixing pipe section 460, the pressure reducing valve 470 and the mass flowmeter 480;
a combustion cap 500.
Detailed Description
Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the accompanying drawings are used to supplement the description of the written description so that one can intuitively and intuitively understand each technical feature and overall technical scheme of the present invention, but not to limit the scope of the present invention.
In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, if there is a word description such as "a plurality" or the like, the meaning of a plurality is one or more, and the meaning of a plurality is two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and above, below, within, etc. are understood to include the present number.
In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.
Referring to fig. 1 to 12, the invention provides an experimental ammonia coal turbulent combustion test system and a combustion control method for an industrial boiler, and the following embodiments are made:
in some embodiments, referring to fig. 1 and 4, an industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system includes an ammonia coal burner 100, a feed gas distribution system 400, a pulverized coal feed system 200, a combustion chamber, and a remote auto-ignition device 300. The flame combustion part of the ammonia coal burner 100 is arranged in the combustion chamber; the feeding and air distribution system 400 can provide various air inlet modes for the combustion main body, and the pulverized coal feeding system 200 is used for pulverized coal feeding, so that the pulverized coal feeding is conveniently and accurately controlled; the combustion chamber comprises a combustion cover 500, and the combustion cover 500 is arranged above the ammonia coal burner 100, so that flame stable combustion can be promoted, and the purposes of more sufficient combustion, increased combustion experiment safety and effectively reduced pollutant emission concentration are realized.
The ammonia coal burner 100 includes a burner body 110, a center fuel tube 120. The inside of the combustion body 110 is provided with a combustion chamber channel, the combustion chamber channel comprises a top discharge chamber 101, a tangential feed chamber 102 and an axial feed chamber 103 which are communicated in sequence, and the three feed chambers are communicated with each other, wherein the top discharge chamber 101, the axial feed chamber 103 and the tangential feed chamber 102 are used for feeding, mixing and circulating different fuels under different combustion modes.
The outer circumferential wall of the combustion body 110 is provided with a cooling water passage 160 in a circumferential direction. In this embodiment, the cooling water channel 160 is a cooling water channel surrounding the outlet end of the combustion body 110, and the cooling water channel is provided with a cooling water inlet 161 and a cooling water outlet 162. The cooling water channel 160 is used for introducing circulating cooling water to cool the ammonia coal burner 100 in real time, so as to prevent the ammonia coal burner 100 from being overheated for a long time and reducing the service life. In other embodiments, the cooling water channel 160 may be a water pipe provided around the circumference of the combustion body 110.
Fig. 3 is a detailed engineering drawing of the center fuel tube 120, including an isometric view and a front view, and the material is preferably SUS316 steel. The central fuel pipe 120 is positioned at the central position of the ammonia coal burner 100, and extends along the axis of the burner body 110, and two ends of the central fuel pipe 120 are respectively provided with a central feed inlet 121 and a central discharge outlet 122. The diameter is 1/6-1/4 of the fuel cavity, and consists of a vertical circular tube which penetrates through the combustion cavity channel but is not communicated with the top discharging cavity 101, the tangential feeding cavity 102 and the axial feeding cavity 103.
The outlet end of the central fuel pipe 120 is connected with the flow-guiding blunt body 140 or the closed blunt body 150 through threads, referring to fig. 4 and 5, the flow-guiding blunt body 140 is further included, the flow-guiding blunt body 140 includes a nozzle portion 141 plugged at the outlet end of the central fuel pipe 120 and a first inverted cone flow-guiding block 142 provided at the nozzle portion 141, and the nozzle portion 141 is provided with a spray outlet 1411;
referring to fig. 6 and 7, the closed blunt body 150 includes a blocking portion 151 at the outlet end of the central fuel pipe 120 and a second inverted cone flow block 152 disposed at the blocking portion 151;
the inverted cone diversion shape can rapidly guide flame forming, promote flame propagation, be favorable for flame stabilization and reduce the generation of backfire; the bluff body 150 is configured to enclose the center fuel tube 120 in a premix mode. The flow guiding blunt body 140 and the closed blunt body 150 can automatically design the inclined angles of different flow patterns and angles according to the flow guiding effect required by experimental conditions, so that researchers in a laboratory can conveniently explore the influence of different blunt body shapes and flow guiding angles on the stability and emission characteristics of ammonia coal combustion flame. In other embodiments, the deflector body 140 and the closure body 150 may alternatively be omitted.
The outlet end of the combustion chamber channel is provided with a total outlet 104, the outlet end of the central discharge port 122 is arranged at the total outlet 104, a rotational flow structure 130 is arranged between the total outlet 104 and the central discharge port 122, the rotational flow structure 130 comprises a rotational flow base and rotational flow fan blades, and the rotational flow fan blades are shown in reference to fig. 2.
The included angle theta between the rotational flow fan blade and the central axis of the rotational flow base can be independently designed according to the rotational flow strength required by the experimental specific conditions, wherein the rotational flow number S of the rotational flow fan blade is defined by the following formula (1):
wherein d i 、d o Respectively representing the inner diameter and the outer diameter of the rotational flow fan blade, and the unit mm; θ represents the angle of the fan blade to the central axis. The following table 1 designs the rotational flow effect of the ammonia coal burner under different fan blade numbers and different fan blade angles in the application, and is convenient for the staff in the laboratory to explore the influence of the combustion flame stability and emission characteristics of the ammonia coal according to different rotational flow intensities.
TABLE 1 intensity of rotational flow at different blade counts and different angles
The swirling effect of the ammonia coal burner in the present application under the conditions of 12 blades and 45 degrees of blade angle is designed as shown in fig. 2, which comprises front view, top view, section view and two axial views. Wherein the threads are provided with inner walls penetrating, and the material is more preferably 310 steel.
The tangential feed cavity 102 is located in the middle of the ammonia coal burner 100 and is configured as a cylinder or square structure with the diameter 1.3-1.8 times that of the fuel cavity, a plurality of tangential feed inlets 105 are arranged at non-diameter chords around the cross section of the tangential feed cavity 102, that is, the circumferential wall of the tangential feed cavity 102 is provided with the tangential feed inlets 105, and the axis of the tangential feed inlets 105 is arranged along the tangential direction of the periphery of the tangential feed cavity 102, so that the gas from the tangential feed inlets 105 is prevented from being directly sprayed on the central fuel pipe 120, and the gas from the tangential feed inlets 105 is beneficial to mixing and swirling in the tangential feed cavity 102. The number of the tangential feed inlets 105 is preferably 4, the number of the tangential feed inlets 105 can be set to be 4, 8 and other numbers according to the requirements by a person in the field, and the 4 tangential feed inlets 105 are diagonally arranged at 1/4-1/3 parts of the side wall of the section so as to form circumferential vortex flow.
The porous air guide structure 130 is arranged between the tangential feeding cavity 102 and the axial feeding cavity 103, the porous air guide structure 130 is preferably made of anti-corrosion honeycomb ceramics, and due to the characteristics of porous thin walls, the honeycomb ceramic filler has larger specific surface area than other fillers, so that the combustion distribution is more uniform, the mixing effect is better, the thermal shock resistance is improved, the use strength is increased, and the service life is greatly prolonged.
The axial feeding cavities 103 are located at the middle lower part of the ammonia coal burner 100, the bottoms of the axial feeding cavities are respectively provided with a plurality of axial feeding openings 106, the number of the axial feeding openings 106 is preferably 4, and the axial feeding openings 106 can be set to 2, 6, 8 and other numbers according to the requirements by a person skilled in the art, and are respectively arranged at two sides or the periphery of the surrounding center fuel pipe 120.
The feed gas distribution system 400 comprises a methane supply assembly, an ammonia gas supply assembly and an air supply assembly, wherein the air supply assembly is connected with an outlet of the pulverized coal feed system 200 to be connected with a first mixing pipe section 440, the outlet of the first mixing pipe section 440 is simultaneously communicated with a tangential feed inlet 105 and an axial feed inlet 106, the air supply assembly is connected with an outlet of the methane supply assembly to be connected with a second mixing pipe section 450, the second mixing pipe section 450 is communicated with the axial feed inlet 106, the outlets of the methane supply assembly and the ammonia gas supply assembly are connected with a third mixing pipe section 460, and the outlet of the third mixing pipe section 460 is communicated with a central feed inlet 121.
In this embodiment, the ammonia supply assembly includes an ammonia gas cylinder 420, the air supply assembly includes an air cylinder 410, and the methane supply assembly includes a methane cylinder 430. In other embodiments, the methane supply assembly, ammonia supply assembly, air supply assembly include other gas storage devices or gas generating devices that produce the respective gases. For example, the air supply assembly includes an air pump and the ammonia supply assembly includes an ammonia generating device.
Wherein, the methane/ammonia gas is supplied by a gas cylinder with the purity of 99.99 percent, the methane and the liquid ammonia flow out of the gas cylinder after being decompressed by a decompression valve 470, and the liquid ammonia is gasified by the decompression valve 470 to obtain gaseous NH 3 . The air compressor provides oxidant air, and the oxidant air is dried by the cold dryer and then is introduced into the air channel. The pipelines of each gas outlet bottle and each mixing pipeline are provided with a pressure reducing valve 470 and a mass flowmeter 480, and the methane/ammonia gas/air flow is precisely controlled by the mass flowmeter 480 with the precision of +/-2%.
The air path is divided into two parts, one part is a primary air path 201 and the other part is a grading air path 202, the primary air path 201 is used for carrying pulverized coal into the ammonia coal burner 100 from the axial feed port 106 or the tangential feed port 105 in a carrying flow combustion mode, the grading air path 202 is used for being introduced in all combustion modes, and the purpose of the grading air path 202 is to support fuel to burn, so as to explore the influence of the grading combustion on the combustion characteristics and pollutant emission of the ammonia coal mixed combustion. Methane and ammonia are mixed and introduced as gas fuel, wherein the methane is used as auxiliary combustion gas, and the methane gas is firstly ignited at the beginning of experiments, so as to provide a combustible environment of the ammonia and the coal dust, and after the temperature is increased to 500-800 ℃, the ammonia and the coal dust are introduced, and the mixing proportion of the ammonia and the coal dust is gradually increased until the pure ammonia/pure coal dust is combusted. The premixed combustion mode is a mode in which ammonia and methane are premixed with the classifying air and then introduced through the axial feed port 106, and the non-premixed combustion mode is a mode in which ammonia and methane are introduced directly through the center feed port 121 without being mixed with the classifying air.
The first mixing pipe section 440, the second mixing pipe section 450 and the third mixing pipe section 460 are all provided with mixers, and a plurality of groups of forward and reverse rotation blades are arranged in the mixers, wherein the number of the forward and reverse rotation blades can be one group, two groups, three groups and the like. The mixer is used for fully mixing the multiple air inlets controlled by the mass flowmeter 480 into one premixed air, so that the mixed fuel is fully and uniformly mixed when reaching the outlet of the ammonia coal burner 100. The feeding and air distribution system designs two feeding modes of pulverized coal carrying flow and single particle suspension, and each feeding mode comprises four combustion modes. In the single-particle suspension mode, pulverized coal particles are suspended on a metal wire mesh in a combustion chamber, and other air inlet modes are the same as those in the carrying flow mode and are used for directionally tracking the combustion state and characteristics of the pulverized coal single particles.
The invention discloses working condition design and calculation of an ammonia coal burner.
The ammonia coal burner adopts CH 4 /NH 3 The coal/air blending is carried out at normal temperature and normal pressure as fuel. The required air amount calculation uses the following combustion equations (2) - (4):
coal +2O 2 →CO 2 (2)
CH 4 +2O 2 →CO 2 +2H 2 O (3)
NH 3 +0.75O 2 →0.5N 2 +1.5H 2 O (4)
Under the combustion condition, the equivalent ratioThe calculation relation of (c) is as follows (5):
in the formula, is marked as V NH3 、V CH4 、V air The flow rates of ammonia, methane and air are respectively, and the ammonia doping proportion C in the experiment NH3 The calculation method is as follows formula (6):
the invention respectively carries out mixed combustion tests (before adding pulverized coal) with different ammonia mixing ratios under lean combustion, theoretical air and rich combustion conditions, and the test working conditions are shown in the following table 2. As can be seen from the data in the table, the spiked combustion system has a wide combustion power turndown ratio (3.0-10.9 kW).
TABLE 2 working conditions of lean and rich combustion tests (before pulverized coal addition) at different Ammonia blending ratios
The premixing is different from the non-premixing in that the fuel and the air are premixed in advance, and the fuel is mixed more fully and uniformly, so that stable combustion can be achieved at a smaller outlet speed, and the stable combustion limit is greatly widened.
TABLE 3 variation of burner power at different Ammonia and equivalent ratios (before pulverized coal addition)
At a gas combustion equivalent ratio ofThe pulverized coal combustion air excess coefficient psi=1.1, the auxiliary gas methane flow is fixed to be 4L/min as a design working condition, the rated total power of the pulverized coal/ammonia cyclone ammonia coal burner 100 is set to be 20kW, and the combustion working condition design with the mixing ratio of 10%, 20%, 30%, 50%, 75% and 100% pure ammonia is carried out in an axial non-premixed combustion mode. As shown in the following Table 4, it can be seen from the table that the pulverized coal velocity ranges from 0 to 44.58g/min, the ammonia flow rate ranges from 8.41 to 84.11L/min, and the air flow rate ranges from 300.26 to 336.33L/min, while the air flow rate ranges from large.
TABLE 4 Combustion Condition design for different Ammonia blending ratios in axial non-premixed Combustion at 20kW rated Power
The combustion working condition design of pure ammonia with the mixing ratio of 10%, 20%, 30%, 50%, 75% and 100% is carried out under the axial non-premixed combustion mode by using the gas combustion equivalent ratio variation range of 0.7-1.2 and other parameters as above. As shown in Table 5 below, the actual total air volume (205.21-428.94L/min) and air outlet velocity (1.17-8.71L/min) vary widely.
TABLE 5 Combustion Condition design for different equivalence ratios and different Advances in axial non-premixed Combustion at 20kW rated Power
Fig. 4 and 5 are schematic cross-sectional views of the axial non-premixed combustion mode and a partially enlarged schematic view of the flow-guiding blunt body 140D according to the present invention.
In the entrained flow mode, the axial non-premixed use of the sealing cap 107 seals the tangential feed port 105 to prevent gas within the combustion body 110 from escaping from the tangential feed cavity 102 through the tangential feed port 105.
The central fuel pipe 120 is connected with the inverted cone-shaped flow guiding blunt body, and is jointly installed on the combustion body 110 for fuel gas circulation, so that the influence of the ammonia gas/methane in advance with the oxidant air on non-premixed experimental data is avoided.
Primary air and grading air carrying pulverized coal are respectively introduced into a plurality of different axial feeding cavities 103 at the bottom of the axial feeding cavity 103, and the pulverized coal and oxidant air are uniformly distributed in the internal space of the combustion body 110 after being guided, circulated and mixed through the axial feeding cavity 103, the porous air guide structure 130 with larger aperture and the top discharging cavity 101, and finally flow out from the main outlet 104, the porous air guide structure 130 is used for preventing the pulverized coal from being blocked, and in the process of flowing out the pulverized coal and the oxidant air from the main outlet 104, the swirl fan blades can cut the pulverized coal and the oxidant air for a plurality of times according to the flow patterns and angles of the fan blades, so that the pulverized coal and the air are cut into swirl states to be sprayed out.
After being mixed by the third mixing pipe section 460, the ammonia gas and the auxiliary gas methane are uniformly introduced into the central fuel pipe 120 through the central feed inlet 121 and are sprayed out through the central discharge outlet 122 at the top end of the central fuel pipe 120. Ammonia and methane flow from the central discharge port 122 to the first back taper flow guide block 142, and the first back taper flow guide block 142 dispersedly guides the ammonia and methane to flow in a direction away from the axis of the combustion body 110, so that the methane/ammonia can be mixed with the oxidant air flowing from the swirl vanes and the coal dust. The oxidant air is thoroughly mixed with the methane/ammonia/coal fines at the general outlet 104, including the swirl vane outlet and the outlet of the central discharge port 122 of the central fuel tube 120, and ignited to form an axially non-premixed ammonia-coal burning swirl flame.
Fig. 6 and 7 are schematic cross-sectional views of the carrier flow axial premixed combustion mode and a partially enlarged schematic view of the closed blunt body 150C according to the present invention.
In the entrained flow mode, the axial premixing uses a sealing cap 107 to seal the tangential feed port 105 to prevent gas within the combustion body 110 from escaping from the tangential feed cavity 102 through the tangential feed port 105.
The closed blunt body 150 is connected to the central fuel pipe 120, and is commonly mounted on the combustion body 110 to prevent the fuel gas from flowing, so as to prevent the methane/ammonia/coal dust/air from flowing back to the central fuel pipe 120 at the main outlet 104 to affect the experimental data or avoid tempering to increase the experimental risk. Or the central fuel pipe 120 is directly removed as shown in fig. 6, and since the central fuel pipe 120 is connected with the combustion body 110 and the axial feeding cavity 103 through threads, free switching between premixing and non-premixing according to the needs of the experimenter in the field is very convenient. After the central fuel pipe 120 is removed, the central feed port 121 and the axial feed chamber 103 are in the same function, and the axial feed chamber 103 is in communication with each other.
The primary air, the classifying air, ammonia and methane which carry the pulverized coal, the methane/ammonia/pulverized coal and the oxidant air are respectively introduced into a plurality of different axial feeding cavities 103 at the bottom of the axial feeding cavity 103, and are uniformly distributed in the inner space of the combustion body 110 after being sequentially guided, circulated and mixed by the axial feeding cavity 103 and the porous air guide structure 130 with larger aperture to prevent the pulverized coal from blocking, the top discharging cavity 101, and finally flow out from the main outlet 104, and the pulverized coal and the oxidant air are cut according to the blade flow pattern and angle in the process of flowing out from the top blade A by the cyclone blade, so that the methane/ammonia/pulverized coal and the oxidant air are changed into a cyclone state to be sprayed out at the cyclone blade and are ignited to form an axial premixed ammonia coal combustion cyclone flame.
FIG. 8 is a schematic cross-sectional view of the carrier flow tangential non-premixed combustion mode according to the invention.
In the tangential non-premixed mode of carrying flow, in order to prevent the swirling flame from being irregularly blown to a certain side, it is necessary to balance the velocity component in the injection direction of the tangential fuel, the primary air carrying the pulverized coal is divided into several strands (the two-way 2 strands, the three-way 3 strands, the four-way 4 strands … … can be set by the person in the field according to the requirements), and then several strands of primary air carrying the pulverized coal are respectively introduced from tangential feed inlets 105 connected with the tangential feed cavities 102 in a plurality of different directions.
After the primary air and the pulverized coal flow into the tangential feed cavity 102 along the tangential feed opening 105, the primary air and the pulverized coal form a rotational flow after entering the tangential feed cavity 102 because the tangential feed opening 105 is tangential to the tangential feed cavity 102. The classifying air is introduced from the axial feeding cavity 103 at the bottom of the axial feeding cavity 103, guided and circulated by the axial feeding cavity 103, the porous air guide structure 130 with smaller aperture and the top discharging cavity 101, and meanwhile, the classifying air drives the pulverized coal and the primary air to be mixed at the vertical upward dividing speed and then uniformly distributed in the combustion cavity of the combustion body 110, and finally flows out from the total outlet 104, and the pulverized coal and the oxidant air are cut by the cyclone fan blades according to the fan blade flow pattern and angle in the flowing process of the pulverized coal and the oxidant air from the total outlet 104, so that the pulverized coal and the air are changed into a cyclone state to be sprayed out.
The central fuel pipe 120 is connected by the flow-guiding blunt body 140, and is commonly installed on the combustion body 110 for fuel gas circulation, so as to prevent the methane/ammonia from being contacted with the oxidant air in advance to affect the non-premixed experimental data.
The ammonia gas and methane are mixed by the third mixing pipe section 460, then evenly introduced into the central fuel pipe 120, and sprayed out through the central discharge port 122 at the top end of the central fuel pipe 120. Ammonia and methane are sprayed from the central discharge hole 122 and then flow to the first back taper flow guiding block 142, and the first back taper flow guiding block 142 dispersedly guides the ammonia and methane to flow in a direction away from the axis of the combustion body 110, so that the methane/ammonia can be mixed with oxidant air flowing from the swirl vanes and coal dust. The oxidant air will be thoroughly mixed with the methane/ammonia/coal fines at the general outlet 104 and ignited to form a tangential non-premixed ammonia coal combustion swirling flame.
By adjusting the inlet air flow and inlet air ratio in the tangential feed inlet 105 and the axial feed chamber 103, the method can be used for an experimenter in the field to explore the influence of an air classification strategy on the combustion characteristics of ammonia coal and the pollutant emission concentration, and can be used for realizing the regulation of the combustion flame of the ammonia coal with different swirl effects.
Referring to FIG. 9, a schematic cross-sectional view of the tangential premixed combustion mode of carrying flow according to the present invention is shown.
In the tangential premix mode of carrying flow, in order to prevent swirl flame from deflecting to a certain side, it is necessary to balance the inflow direction of tangential fuel, first divide the primary air carrying pulverized coal into several strands (2, 3 and 4 strands … … according to the requirements of the person skilled in the art), and then introduce several strands of primary air carrying pulverized coal into the tangential feed inlets 105 connected with the tangential feed chambers 102 in different directions. After the primary air and the pulverized coal flow into the tangential feed cavity 102 along the tangential feed opening 105, the primary air and the pulverized coal form a rotational flow after entering the tangential feed cavity 102 because the tangential feed opening 105 is tangential to the tangential feed cavity 102.
Referring to fig. 9, a closed blunt body 150 is used to connect the central fuel pipe 120, and is jointly mounted on the combustion body 110 to prevent the fuel gas from flowing, and prevent the methane/ammonia/coal dust/air from flowing back to the central fuel pipe 120 at the main outlet 104 to affect experimental data or to increase experimental risk due to tempering. Or directly removing the central fuel tube 120 (not shown), since the central fuel tube 120 is connected to the burner body 110 and the axial feed cavity 103 by threads, it is very convenient for the experimenter in the art to freely switch between premixing and non-premixing according to the need. After the central fuel pipe 120 is removed, the central feed port 121 and the axial feed chamber 103 are in the same function, and the axial feed chamber 103 is in communication with each other.
The method comprises the steps that classified air is respectively introduced into a plurality of different axial feeding cavities 103 at the bottom of an axial feeding cavity 103, methane and ammonia sequentially pass through the axial feeding cavity 103, a porous air guide structure 130 with smaller aperture and a top discharging cavity 101 for guiding and circulating, meanwhile, the classified air, methane and ammonia drive coal dust and primary air to be mixed at vertical upward separating speed, the coal dust and primary air are uniformly distributed in the inner space of a combustion body 110, and finally, the coal dust and oxidant air flow out from a main outlet 104, and in the process of flowing out from a top swirl fan blade, the swirl fan blade can cut the coal dust and the oxidant air according to the fan blade flow pattern and angle, so that the coal dust and the air are changed into a swirl state to be sprayed out, and the tangentially premixed ammonia coal combustion swirl flame is formed by ignition.
By adjusting the inlet air flow and inlet air ratio in the tangential feed inlet 105 and the axial feed chamber 103, the method can be used for an experimenter in the field to explore the influence of an air classification strategy on the combustion characteristics of ammonia coal and the pollutant emission concentration, and can be used for realizing the regulation of the combustion flame of the ammonia coal with different swirl effects.
FIG. 10 is a schematic diagram of a pulverized coal feeding system according to the present invention.
Accurate control is crucial to continuously and stably micro-feeding, because uneven feeding operation is extremely easy to cause particle agglomeration and adhesion phenomenon, so that stable observation of the ignition process of pulverized coal particles with extremely short existing time cannot be realized.
In order to realize continuous feeding and micro feeding, a coal powder feeding system 200 is designed, the coal powder feeding system 200 comprises an ammonia coal mixer 210 and a coal powder feeder 220, a primary air inlet 211 is arranged at the upper end of the ammonia coal mixer 210, a mixing outlet 212 is arranged at the lower end of the ammonia coal mixer 210, and the coal powder feeder 220 is used for conveying coal powder into the ammonia coal mixer 210.
The pulverized coal feeding system 200 further comprises a mounting frame 230, the ammonia-coal mixer 210 is provided with a mixing cavity with an inverted cone shape, a discharge end of a pulverized coal feeding pipe 221 of the pulverized coal feeder 220 is arranged on an air outlet path where the primary air inlet 211 is located, a first vibrator 240a is arranged between the pulverized coal feeding pipe 221 and the ammonia-coal mixer 210, the pulverized coal feeder 220 is arranged on the mounting frame 230 through a plurality of second vibrators 240b, and the pulverized coal feeding pipe 221 is arranged on the mounting frame 230 through a plurality of third vibrators 240 c.
In the embodiment, a micro-feeding system is adopted, the feeding system controls the powder feeding speed by using a servo motor, the vibrating screen keeps particles dispersed, meanwhile, the carrying airflow can freely control the flow, and the powder feeding speed range is designed to be 0.1-50g/min with reference to the combustion working condition designs of different ammonia mixing ratios in axial non-premixed combustion under the rated power of 20kW provided by the table 4, and the feeding precision is set value of +/-2%.
The micro-feeding system mainly comprises a stepping cylinder feeder 250, wherein the stepping cylinder feeder 250 comprises a servo motor, a PLC (programmable logic controller) feeding controller, a large-range injection tube, an ammonia coal mixer 210, a coupler, a speed reducer, a ball screw, a support rack, a control cabinet and the like, the working principle is that the top end of the large-range injection tube is cut off, the rest is used as a piston type injection tube, then the rotating power of the servo motor is converted into micro-feeding thrust to the piston type injection tube through the speed reducer, the coupler, the ball screw and other power transmission components, pulverized coal in the injection tube can be continuously fed into the ammonia coal mixer 210 in a micro-amount through a pulverized coal inlet, primary air flow entering through the top inlet of the ammonia coal mixer 210 and primary air carrying pulverized coal are formed through an air-coal mixing outlet, and the pulverized coal is gradually pushed into a third mixing 460 by the ammonia coal mixer 210 through the carrying air flow and then fed into the ammonia coal burner 100 for combustion.
The pulse signal of the servo motor is input through the control cabinet, the square wave signal supplied by the PLC feed control program controls the servo motor to act, so that the rotation speed of the servo motor can be conveniently and simply regulated, and the powder feeding amount is controlled and regulated; in order to further realize stable and continuous feeding, a plurality of vibration eccentric wheels are arranged at different positions on the support rack, each vibration eccentric wheel comprises two second vibrators 240b, a first vibrator 240a and a third vibrator 240c, and vibration with certain frequency and amplitude is added to ensure that coal dust is vibrated to be in a dispersed state all the time, and meanwhile, the coal dust adhered to the wall surface of the ammonia coal mixer 210 is vibrated to promote the updating and the continuity of powder feeding.
The primary air carries airflow and is separated from pulverized coal relatively, so that normal powder feeding is not influenced by fluctuation of flow of the carried airflow, and the flow of the primary air can be flexibly regulated within a certain range of 0.5-50L/min according to experimental requirements.
FIG. 11 is a graph showing the calibration of the feed rate of a servo motor according to the present invention, in which dry small-sized 20 μm flat sand-mixed C coal particles were used as raw materials for calibrating the feed rate of pulverized coal in the present ammonia coal combustion experiment, a square wave pulse signal value range of 400-2200 (10 3 ) The adjustment range of the carried air flow is 0.5-50L/min, and the measured mass flow rate adjustment range is 5-50g/min under the condition of 20L/min of air inflow, so that the linear relation R between the speed of carrying powder and the pulse feeding amount provided by a servo motor can be obtained 2 =0.9984, which illustrates that the carrying powder feeding speed can be precisely controlled by controlling the pulse signal provided by the servo motor.
FIG. 12 is a schematic view of a combustion chamber and remote auto-ignition device according to the present invention.
In the ammonia coal combustion experiment process, the combustion chamber is preferably a bottle-shaped quartz glass cover, and the combustion chamber can be arranged into a cylinder cover, a cuboid cover and the like according to requirements by experimenters in the field, so that different heights and shapes of quartz glass can have great influence on the flow field structure and the emission performance in the combustion chamber. The inner central reflux zone is not fully developed when the height of the combustion chamber is lower, so that the higher quartz glass is designed so that a more complete reflux zone flow field can be formed in the combustion chamber, and under the same condition, the combustible gas fully reacts in the higher combustion chamber and has longer residence time, so that the flame in the higher combustion chamber is higher in expansion, the combustion is more sufficient, and the generated pollutant emission concentration is lower. In addition, the height of the combustion chamber also affects the concentration distribution of the premixed gas at the upper part of the outlets of the swirl vanes, and the lower combustion chamber is highly easy to form flame which is lifted out of the glass cover completely, because the ammonia concentration at the outlet of the lower combustion chamber is still in a combustible range, while the ammonia concentration at the outlet of the higher combustion chamber is lower, the ammonia reaction is more sufficient, and the combustion is difficult to be performed again.
Therefore, the combustion chamber is designed to be longer in height and cylindrical in shape, flame stabilization can be promoted, combustion is more sufficient, and pollutant emission concentration is effectively reduced; meanwhile, the middle and upper parts of the combustion chamber are in a truncated cone shape with the diameter gradually reduced from bottom to top, so that flame lifting can be greatly limited, and flame falling can be prevented; meanwhile, the gas backflow at the burner main outlet 104 is avoided, and the backfire is reduced; the limit of ammonia coal combustion can be widened to a certain extent, the structure of the burner can be protected, and the service life is prolonged.
Because the turbulent ammonia combustion flame has larger flow and high swirl strength, violent explosion can be generated at the moment of being ignited, the explosion residual wave impact is very large, and in a laboratory-grade combustor, if a conventional ignition mode is used for the turbulent combustor: the ignition part of the manual operation lighter extends into the combustion chamber to be ignited near the central discharge hole 122, and has great personal safety hidden trouble for experimental operators. To effectively eliminate this hidden danger, the present invention specifically contemplates a remote automatic ignition device 300.
The remote auto-ignition device 300 mainly comprises an ignition end of a flameless igniter 330, a liftable and steerable "T" shaped bracket 320, a wire and a remote control part, wherein the remote control part comprises a lighter ignition control and a "T" shaped bracket lifting and steering control 310.
The improved flameless igniter 330 is hung and fixed at one end of the T-shaped bracket 320 by constructing the T-shaped bracket 320 which can be lifted up and down and turn circumferentially at the side edge of the burner platform, the right lower part of the ignition end coincides with the axial direction of the ammonia coal burner 100, and the bracket end, the lighter and the top distance of the ammonia coal burner 100 are arranged, so that the electric arc of the lighter is ensured to be right aligned with the upper part of the fuel outlet. The wires near the burner end are disposed along the "T" shaped support 320, with the remainder being routed to the lighter control portion by the wires of the spiral wrap 340 at a safe distance from the distal end, such as 6 meters away, which can be set by those skilled in the art to 8 meters, 10 meters … …, as desired. When the ignition is needed to be operated, after fuel is introduced into the ammonia coal burner 100 and enters the combustion chamber from the fuel outlet, the remote control automatic ignition can be realized only by pressing an ignition button on a remote ignition control part, and after the ignition is successful, experimental operators can control the operation to lift and turn through a T-shaped bracket, so that the lighter can be quickly removed from the combustion chamber. The design is simple, the operation is convenient, and the safety and the reliability of laboratory operators are greatly improved.
In addition, since the remote automatic ignition device 300 has the function of quickly and remotely operating the T-shaped bracket 320 and the automatic igniter 330, if the ammonia coal is carelessly extinguished in the operation process of the ammonia coal combustion experiment (the ammonia combustion experiment is easy to cause flameout due to the reasons of equivalent ratio, mixing ratio or flow velocity, etc.), the remote automatic ignition device 300 can quickly re-stretch into the ignition end of the igniter 330 for ignition, and the temperature environment in the combustion chamber is in accordance with the ammonia coal combustion condition, so that the remote automatic ignition device has the function of ensuring successful re-ignition in a short time of flameout.
While the preferred embodiments of the present invention have been illustrated and described, the present invention is not limited to the examples, and various equivalent modifications and substitutions can be made by one skilled in the art without departing from the spirit of the present invention, and these equivalent modifications and substitutions are intended to be included in the scope of the present invention as defined in the appended claims.
Claims (10)
1. An experimental ammonia coal turbulent combustion test system for an industrial boiler is characterized in that,
comprising the following steps:
a combustion chamber;
the ammonia coal burner (100) is arranged in the combustion chamber, the ammonia coal burner (100) comprises a combustion body (110) and a central fuel pipe (120), a combustion cavity channel is arranged in the combustion body (110), the combustion cavity channel comprises a top discharging cavity (101), a tangential feeding cavity (102) and an axial feeding cavity (103) which are sequentially communicated, the central fuel pipe (120) penetrates through the combustion cavity channel, a tangential feeding port (105) is formed in the circumferential wall of the tangential feeding cavity (102), the axis of the tangential feeding port (105) is arranged along the tangential direction of the periphery of the tangential feeding cavity (102), and a rotational flow structure (130) is arranged between the outlet end of the combustion cavity channel and the outlet end of the central fuel pipe (120);
A pulverized coal feeding system (200) for feeding pulverized coal;
the feed gas distribution system (400) comprises a methane supply assembly, an ammonia gas supply assembly and an air supply assembly, wherein the air supply assembly is connected with an outlet of the pulverized coal feed system (200) to be connected with a first mixing pipe section (440), the outlet of the first mixing pipe section (440) is simultaneously communicated with a tangential feed inlet (105) and an axial feed inlet (106), the air supply assembly is connected with an outlet of the methane supply assembly to be connected with a second mixing pipe section (450), the second mixing pipe section (450) is communicated with the axial feed inlet (106), the outlets of the methane supply assembly and the ammonia gas supply assembly are connected with a third mixing pipe section (460), and the outlet of the third mixing pipe section (460) is communicated with a central feed inlet (121).
2. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 1, wherein:
the device further comprises a flow guide blunt body (140), wherein the flow guide blunt body (140) comprises a nozzle part (141) plugged at the outlet end of the central fuel pipe (120) and a first inverted cone flow guide block (142) arranged at the nozzle part (141), and the nozzle part (141) is provided with a spray outlet (1411);
still or further include and seal blunt body (150), seal blunt body (150) include the shutoff portion (151) of the exit end of central fuel pipe (120) and locate the second back taper guide block (152) of shutoff portion (151).
3. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 1, wherein:
a cooling water channel (160) is circumferentially arranged on the outer peripheral wall of the combustion body (110).
4. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 1, wherein:
also included is a remote auto-ignition device (300), the remote auto-ignition device (300) including an igniter (330), an ignition end of the igniter (330) being adjustable in axial and radial directions relative to an outlet end of the combustion chamber path while the outlet end of the combustion chamber path is located in a rotational path of the igniter (330).
5. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 1, wherein:
the combustion chamber comprises a combustion cover (500), wherein the lower part of the combustion cover (500) is cylindrical, and the upper part of the combustion cover (500) is in a truncated cone shape with the diameter gradually reduced from bottom to top.
6. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 5, wherein:
a pulverized coal particle suspension net is arranged in the combustion cover (500).
7. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 1, wherein:
the pulverized coal feeding system (200) comprises an ammonia coal mixer (210) and a pulverized coal feeder (220), wherein a primary air inlet (211) is formed in the upper end of the ammonia coal mixer (210), a mixing outlet (212) is formed in the lower end of the ammonia coal mixer (210), and the pulverized coal feeder (220) is used for conveying pulverized coal into the ammonia coal mixer (210).
8. An industrial boiler-oriented laboratory grade ammonia coal turbulent combustion test system as claimed in claim 7, wherein:
the coal dust feeding system (200) further comprises a mounting frame (230), the ammonia coal mixer (210) is provided with a mixing cavity in an inverted cone shape, the discharge end of a coal dust feeding pipe (221) of the coal dust feeder (220) is arranged on an air outlet path where the primary air inlet (211) is located, a first vibrator (240 a) is arranged between the coal dust feeding pipe (221) and the ammonia coal mixer (210), the coal dust feeder (220) is arranged on the mounting frame (230) through a plurality of second vibrators (240 b), and the coal dust feeding pipe (221) is arranged on the mounting frame (230) through a plurality of third vibrators (240 c).
9. A combustion control method, characterized in that the experimental ammonia coal turbulent combustion test system for an industrial boiler is adopted, and the experimental ammonia coal turbulent combustion test system comprises the following components:
In the feed mode of the pulverized coal carrying stream, four combustion modes are included:
in the first premixing mode, air, coal dust, ammonia gas and auxiliary gas methane are introduced into a plurality of axial feed inlets (106);
in the second premixing mode, primary air carrying pulverized coal is introduced into a tangential feed inlet (105), and classified air, ammonia and methane are introduced into an axial feed inlet (106);
in the first non-premixing mode, air and coal dust are introduced into an axial feed inlet (106), and ammonia and methane are introduced into a central feed inlet (121);
in a second non-premixing mode, classifying air is introduced into the axial feed inlet (106), ammonia and methane are introduced into the central feed inlet (121), and primary air carrying pulverized coal is introduced into the tangential feed inlet (105);
in the single-particle suspended feeding mode, the pulverized coal feeding system (200) is closed, the four combustion modes are included, the other air inlet modes are the same as those in the carrying flow mode, and pulverized coal is suspended outside the ammonia coal burner (100) and combusted with gas sprayed out of the ammonia coal burner (100) in a mixed mode.
10. A combustion control method according to claim 9, characterized in that:
when the first premixing mode and the second premixing mode are needed, the closed blunt body (150) is arranged at the outlet end of the central fuel pipe (120) (the central fuel pipe (120) can be disassembled according to the needs at the moment)
Except or not removed, with consistent effect); when a non-premixed mode one and a non-premixed mode two are desired,
the outlet end of the central fuel pipe (120) is provided with a diversion blunt body (140).
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