WO2020207318A1 - 多级回流逆喷式旋流煤粉燃烧器 - Google Patents

多级回流逆喷式旋流煤粉燃烧器 Download PDF

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Publication number
WO2020207318A1
WO2020207318A1 PCT/CN2020/082896 CN2020082896W WO2020207318A1 WO 2020207318 A1 WO2020207318 A1 WO 2020207318A1 CN 2020082896 W CN2020082896 W CN 2020082896W WO 2020207318 A1 WO2020207318 A1 WO 2020207318A1
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WIPO (PCT)
Prior art keywords
pulverized coal
secondary air
air
primary air
flow
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PCT/CN2020/082896
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English (en)
French (fr)
Inventor
李水清
宋民航
高琦
许扬
卓建坤
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清华大学
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Application filed by 清华大学 filed Critical 清华大学
Publication of WO2020207318A1 publication Critical patent/WO2020207318A1/zh
Priority to US17/478,896 priority Critical patent/US12117168B2/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D1/00—Burners for combustion of pulverulent fuel
    • F23D1/02—Vortex burners, e.g. for cyclone-type combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
    • F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
    • F23C6/042—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with fuel supply in stages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/006—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber the recirculation taking place in the combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L9/00—Passages or apertures for delivering secondary air for completing combustion of fuel 
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2201/00—Staged combustion
    • F23C2201/30—Staged fuel supply
    • F23C2201/301—Staged fuel supply with different fuels in stages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2202/00—Fluegas recirculation
    • F23C2202/10—Premixing fluegas with fuel and combustion air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/06041—Staged supply of oxidant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/06043—Burner staging, i.e. radially stratified flame core burners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2201/00—Burners adapted for particulate solid or pulverulent fuels
    • F23D2201/20—Fuel flow guiding devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
    • F23D2900/00003—Fuel or fuel-air mixtures flow distribution devices upstream of the outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
    • F23D2900/01001—Pulverised solid fuel burner with means for swirling the fuel-air mixture
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

  • the application relates to the technical field of pulverized coal combustion equipment, in particular to a multi-stage backflow reverse injection type swirling pulverized coal burner.
  • coal-fired industrial boilers are the main coal combustion equipment other than power station boilers.
  • Traditional coal-fired industrial boilers are mainly based on layer-fired grate furnaces and chain-grate furnaces, that is, lump coal is placed on a fixed or mobile grate to form a fuel layer. Air flows in from the bottom of the grate and flows through the fuel layer for combustion reaction. . Limited by the combustion space and the effective area of the reaction, this type of furnace generally has the problem of low boiler thermal efficiency.
  • the pulverized coal chamber combustion method has gradually replaced pulverized coal bed combustion and has been widely used in coal-fired boilers.
  • This method uses air-carrying pulverized coal particles to be sprayed into the furnace for suspension combustion, which enhances gas-solid mixing and contact, and improves the combustion efficiency and thermal efficiency of the boiler.
  • small and medium-sized industrial boilers have operating characteristics such as large difference in pulverized coal characteristics and wide load adjustment range during actual operation.
  • a multi-stage backflow reverse injection type swirling flow pulverized coal burner including:
  • a pre-combustion housing having a pre-combustion chamber and a housing outlet located on one side of the pre-combustion chamber;
  • the primary air pulverized coal structure extends through the pre-combustion shell into the pre-combustion chamber, and is used to separate the primary air pulverized coal air flow into a dense pulverized coal air flow and a light pulverized coal air flow, and the primary air pulverized coal structure
  • the outlet end extends toward the outlet of the housing;
  • the density output structure is arranged at the outlet end of the primary air pulverized coal structure.
  • the density output structure is used to output the light pulverized coal airflow and block the dense pulverized coal airflow so that the dense pulverized coal airflow flows in the reverse direction to The pre-combustion chamber;
  • the internal secondary air structure is arranged on the pre-combustion shell and is located on the peripheral side of the primary air pulverized coal structure.
  • the internal secondary air structure is used to input the internal secondary air to the pre-combustion chamber so that the The pre-combustion chamber forms a first-stage recirculation zone, and a second-stage recirculation zone is formed at one end of the density output structure away from the primary air pulverized coal structure;
  • the external secondary air structure is sleeved on the outside of the pre-combustion shell and used for conveying the external secondary air so that a third-stage return zone is formed at the outlet of the shell.
  • the pre-combustion housing includes a conical section and the flaring section connected to the conical section, and the end of the flaring section away from the conical section is the pre-combustion Shell outlet of the shell;
  • the inclination angle of the flaring section is greater than the inclination angle of the tapered section.
  • the range of the inclination angle ⁇ of the tapered section is 0° ⁇ 20°;
  • the inclination angle ⁇ of the flaring section ranges from 20° to 50°.
  • the primary air pulverized coal structure includes a primary air pulverized coal gas flow pipe, a fixed shaft and a plurality of swing blades, the fixed shaft is close to the outlet end of the primary air pulverized coal gas flow pipe, and a plurality of The turning vane connects the inner wall of the primary air pulverized coal airflow pipe and the fixed shaft, and is used to separate the primary air pulverized coal airflow into the dense pulverized coal airflow and the light pulverized coal airflow.
  • the density output structure includes a backflow baffle and a light coal pulverized coal gas flow pipe passing through the backflow baffle;
  • the backflow baffle is located at the outlet end of the primary air pulverized coal gas flow pipe, and the surface of the backflow baffle facing the primary air pulverized coal gas flow pipe has a backflow groove, and the backflow groove is used to guide the concentrated coal powder
  • the airflow flows in the reverse direction to the pre-combustion chamber, and the shape of the inner wall of the recirculation tank is linear and/or curved; the inner wall of the recirculation tank and the outer wall of the primary air pulverized coal gas flow pipe are enclosed in a cross-sectional shape of a ring
  • One end of the light coal pulverized coal airflow pipe extends into the middle area of the outlet end of the primary air pulverized coal airflow pipe for outputting the light coal pulverized coal airflow in the primary air pulverized coal airflow pipe.
  • the backflow baffle is arranged in a conical shape, and the cross-sectional size of the backflow baffle toward the end of the primary air pulverized coal gas flow pipe is smaller than that of the backflow baffle away from the primary air pulverized coal flow Sectional size of one end of the tube;
  • the density output structure includes a fixed rib, which connects the return baffle and the primary air pulverized coal flow pipe.
  • the internal secondary air structure includes a strong-rotation internal secondary air component, a weak-rotation internal secondary air component, and a direct-current internal secondary air channel, and the strong-rotation internal secondary air component is sleeved in In the primary air pulverized coal structure, the weak-rotation internal secondary air component is sleeved on the strong-rotation internal secondary air component, and the direct current internal secondary air passage is sleeved on the weak-rotation internal secondary air component ;
  • the tangential rotation speed of the internal secondary air conveyed by the strong internal secondary air assembly, the weak internal secondary air assembly, and the direct-current internal secondary air channel gradually decreases.
  • the strong-spinning secondary air assembly includes a strong-spinning secondary air channel and a strong-spinning axial blade arranged in the strong-spinning secondary air channel.
  • the blades are used to generate a tangential rotation speed of the internal secondary air in the strong swirl internal secondary air channel.
  • the range of the outlet angle ⁇ of the strong rotation axial blade is 50°-80°.
  • the weak-spin secondary air assembly includes a weak-swirl secondary air passage and a weak-swirl axial blade arranged in the weak-swirl secondary air passage, and the weak-swirl axial The blades are used to generate a tangential rotation speed of the internal secondary air in the weak swirl internal secondary air channel.
  • the outlet angle ⁇ of the weak-rotation axial blade ranges from 20° to 50°.
  • the multi-stage backflow reverse injection swirl flow pulverized coal burner further includes an annular connecting body located between the secondary air component in the strong swirl and the primary air pulverized coal structure And connect and fix the strong-rotation internal secondary air component and the primary air pulverized coal structure.
  • the outer secondary air structure includes an outer secondary air inlet channel, an outer secondary air outlet channel, and tangential blades, the outer secondary air inlet channel and the outer secondary air outlet channel They are connected and communicated in a stepped shape, and the tangential blades are arranged at the junction of the outer secondary air inlet channel and the outer secondary air outlet channel.
  • the outlet angle ⁇ of the tangential blade ranges from 15° to 40°.
  • the outer secondary air structure further includes a partition ring disposed at the end of the outer secondary air outlet channel and located on the outer wall of the flaring section.
  • the primary air pulverized coal structure separates the primary air pulverized coal air flow into a dense pulverized coal air flow and a light pulverized coal air flow.
  • the concentrated pulverized coal air flow After the concentrated pulverized coal air flow is blocked by the density output structure , It flows into the pre-combustion chamber in the reverse direction, and works with the internal secondary air to form a first-stage recirculation zone in the pre-combustion chamber, so that the dense pulverized coal gas flow is entrained into the first-stage recirculation zone and burns to release heat; at the same time, due to the return flow
  • the baffle is arranged in a conical shape, so that a second-stage recirculation zone is formed on the side of the density output structure away from the primary air pulverized coal structure to heat the light coal and ignite the light coal flow.
  • the external secondary air structure makes the external secondary air flow form a third-stage recirculation zone at the shell outlet. Promote the burning of unburned coal and stable combustion, and finally spray it into the furnace.
  • the primary air pulverized coal gas flow is concentrated and separated, it is burned in the three-stage recirculation zone, which is conducive to the ignition, stable combustion and burnout of the pulverized coal under different coal types and load conditions. At the same time, it reduces the pulverized coal combustion process. NO x is generated. Coal burnout and effective solution to the difference between low-load stable combustion pulverized coal boiler capacity currently existing industrial high NO x emissions problem.
  • Figure 1 is a front cross-sectional view of a multi-stage backflow reverse injection swirling pulverized coal burner according to an embodiment of the application;
  • Figure 2 is a side view of the multi-stage backflow reverse injection swirling pulverized coal burner shown in Figure 1;
  • Figure 3 is a cross-sectional view at A-A of the multi-stage backflow reverse injection swirling pulverized coal burner shown in Figure 2;
  • Fig. 4 is a perspective view of the secondary air component of the strong swirl in the multi-stage backflow reverse injection swirling pulverized coal burner shown in Fig. 1;
  • Fig. 5 is a perspective view of the secondary air component in the weak swirl in the multi-stage backflow reverse injection swirling pulverized coal burner shown in Fig. 1;
  • Figure 6 is a cross-sectional view at B-B of the multi-stage backflow reverse injection swirling pulverized coal burner shown in Figure 2;
  • Fig. 7 is a perspective view of the tangential blades installed in the pre-combustion shell of the multi-stage backflow reverse injection swirling flow pulverized coal burner shown in Fig. 1;
  • Fig. 8 is a perspective view of the swirling blades of the primary air pulverized coal structure in the multi-stage backflow reverse injection swirling flow pulverized coal burner shown in Fig. 1;
  • Fig. 9 is a schematic diagram of the multi-stage reflux reverse injection swirl flow pulverized coal burner shown in Fig. 1.
  • 100-multi-stage backflow reverse injection swirling pulverized coal burner 110-pre-combustion shell; 111-pre-combustion chamber; 112-cone section; 113-flaring section; 120-primary air pulverized coal structure; 121- Primary air pulverized coal air flow pipe; 122-fixed shaft; 123-rotating blade; 130-concentration output structure; 131-return baffle; 1311-return trough; 132-light pulverized coal airflow pipe; 133-concentrated pulverized coal airflow channel 134-Fixed ribs; 140-Internal secondary air structure; 141-Strong rotary inner secondary air component; 1411-Strong rotary inner secondary air channel; 1412-strong rotary axial blade; 142-weak inner rotary secondary air Components; 1421-Weak-rotation inner secondary air passage; 1422-Weak-rotation axial blades; 143-DC inner secondary air passage; 1431-support ribs; 150-outer
  • connection and “connection” mentioned in this application include direct and indirect connection (connection) unless otherwise specified.
  • connection connection
  • the “on” or “under” of the first feature on the second feature may be in direct contact with the first and second features, or indirectly through an intermediary. contact.
  • the "above”, “above” and “above” of the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the level of the first feature is higher than the second feature.
  • the “below”, “below” and “below” of the second feature of the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the level of the first feature is smaller than the second feature.
  • the present application provides a multi-stage backflow reverse injection type swirl flow pulverized coal burner 100.
  • the multi-stage backflow reverse injection swirling flow pulverized coal burner 100 is applied to an industrial pulverized coal boiler.
  • the multi-stage backflow reverse injection swirling pulverized coal burner 100 of the present application can realize the concentration separation of pulverized coal, multi-stage air flow recirculation, and air atmosphere level combustion, which is beneficial to the ignition and stable combustion of pulverized coal under different coal types and load conditions. and burnout, while reducing coal combustion process NO x in generation.
  • the multi-stage backflow reverse injection swirl flow pulverized coal burner 100 includes a pre-combustion housing 110, a primary air pulverized coal structure 120, a concentration output structure 130, an inner secondary air structure 140, and an outer secondary air structure 150.
  • the primary air pulverized coal structure 120 partially extends into the pre-combustion housing 110 and communicates with the pre-combustion housing 110.
  • the density output structure 130 is located at the end of the primary air pulverized coal structure 120 in the pre-combustion housing 110.
  • the inner secondary air structure 140 is sleeved on the primary air pulverized coal structure 120 on the outside of the pre-combustion housing 110 and communicates with the pre-combustion housing 110, and the outer secondary air structure 150 is sleeved on the outside of the pre-combustion housing 110.
  • the pre-combustion housing 110 has a pre-combustion chamber 111 and a housing outlet located on one side of the pre-combustion chamber 111.
  • the primary air pulverized coal structure 120 passes through the pre-combustion shell 110 and extends into the pre-combustion chamber 111, and is used to separate the primary air pulverized coal air flow into a dense pulverized coal air flow and a light pulverized coal air flow.
  • the outlet end of the primary air pulverized coal structure 120 Extends toward the shell outlet.
  • the density output structure 130 is arranged at the outlet end of the primary air pulverized coal structure 120, and the density output structure 130 is used to output the light pulverized coal airflow and block the concentrated pulverized coal airflow so that the concentrated pulverized coal airflow flows backward to the pre-combustion chamber 111.
  • the inner secondary air structure 140 is arranged on the pre-combustion housing 110 and is located on the peripheral side of the primary air pulverized coal structure 120.
  • the internal secondary air structure 140 is used to input the internal secondary air to the pre-combustion chamber 111 to form a first-stage recirculation zone F in the pre-combustion chamber 111, and to form an end of the density output structure 130 away from the primary air pulverized coal structure 120
  • the second stage reflux area M The outer secondary air structure 150 is sleeved on the outside of the pre-combustion housing 110 for conveying the external secondary air so that a third-stage return zone N is formed at the exit of the housing.
  • the primary air pulverized coal structure 120 inputs the primary air pulverized coal air flow into the pre-combustion chamber 111 of the pre-combustion housing 110.
  • the primary air pulverized coal structure 120 is inputting the primary air pulverized coal air flow
  • the primary air pulverized coal air flow is subjected to density separation to form a dense pulverized coal air flow and a light pulverized coal air flow.
  • the separated concentrated pulverized coal air flow and light pulverized coal air flow flow from the primary air pulverized coal structure 120 into the pre-combustion chamber 111, they will flow into the pre-combustion chamber 111 in different directions through the density output structure 130.
  • the dense pulverized coal airflow After the dense pulverized coal airflow enters the density output structure 130, it will be blocked by the density output structure 130, causing the dense pulverized coal airflow to flow in the opposite direction.
  • the concentrated pulverized coal air flow flows in the direction opposite to the flow direction in the pre-combustion chamber 111. It can be understood that the flow direction here refers to the direction in which the primary air pulverized coal air flow enters the pre-combustion chamber 111.
  • the light pulverized coal air flow continues to flow along the flow direction after passing through the density output structure 130.
  • the internal secondary air flows into the pre-combustion chamber 111 on the peripheral side of the primary air pulverized coal structure 120 through the internal secondary air structure 140.
  • the internal secondary air interacts with the counter-current dense pulverized coal airflow to cause A first-stage recirculation zone F is formed in the pre-chamber 111.
  • the dense pulverized coal gas flow is easily entrained into the first-stage recirculation zone F during the reverse flow process, the dense pulverized coal gas flow is swirling and combusts in the first-stage recirculation zone F to form a high-temperature gas flow, and then flows through the dense and thin output structure 130 and ejected from the outlet of the casing of the pre-combustion chamber 111.
  • a second-stage recirculation zone M is formed on the side of the density output structure 130 away from the primary air pulverized coal structure 120. This part of the refluxed high-temperature air flow is sprayed from the density output structure 130.
  • the pulverized coal air flow meets, it will promote the heating of the pulverized coal air flow, heating and igniting the pulverized coal air flow.
  • the airflow and unburned coal particles in the pre-combustion chamber 111 are ejected from the outlet of the pre-combustion chamber 111 shell.
  • the external secondary air structure 150 inputs the external secondary air on the outside of the pre-combustion housing 110, and forms a third-stage recirculation zone N at the exit of the pre-combustion chamber 111, thereby making the multi-stage recirculation reverse injection swirl
  • the high-temperature reflux flue gas is also generated at the exit of the pulverized coal burner 100, which further promotes the burnout and stable combustion of the unburned pulverized coal ejected from the pre-combustion chamber 111.
  • the amount of oxygen required for the initial stage of pulverized coal combustion is sequentially supplied in two stages by the inner secondary air structure 140 and the outer secondary air structure 150, so that the pulverized coal is always burned in a reducing atmosphere, thereby reducing the combustion process of the pulverized coal.
  • NO x generation the amount of oxygen required for the initial stage of pulverized coal combustion is sequentially supplied in two stages by the inner secondary air structure 140 and the outer secondary air structure 150, so that the pulverized coal is always burned in a reducing atmosphere, thereby reducing the combustion process of the pulverized coal.
  • the pre-combustion housing 110 includes a tapered section 112. Along the flow direction of the primary air pulverized coal structure 120, the cross-sectional size of the tapered section 112 gradually increases. In this way, because the secondary air in the rotation near the primary air pulverized coal structure 120 will drive the primary air pulverized coal air flow, a low pressure area is formed in the central area of the rotating air flow.
  • the side wall of the tapered section 112 of the pre-combustion shell 110 With a certain inclination angle, during the top-down flow of the internal secondary air flow in the pre-combustion housing 110, due to the gradual expansion of the flow area of the air flow, the flow rate of the air flow is reduced, and the static pressure is gradually increased.
  • the function makes the internal secondary air flow in the pre-combustion chamber 111, and part of the internal secondary air flows into the low-pressure zone in the reverse direction, thereby forming the first-stage recirculation zone F in the pre-combustion chamber 111.
  • the pre-combustion housing 110 further includes a flaring section 113 connected to the conical section 112, and the end of the flaring section 113 away from the conical section 112 is a housing outlet of the pre-combustion housing 110.
  • the cross-sectional size of the flaring section 113 gradually increases along the flow direction of the primary air pulverized coal structure 120.
  • the inclination angle of the flaring section 113 is greater than the inclination angle of the tapered section 112. Further, the range of the inclination angle ⁇ of the tapered section 112 is 0° ⁇ 20°. The inclination angle ⁇ of the flaring section 113 ranges from 20° to 50°.
  • the primary air pulverized coal structure 120 includes a primary air pulverized coal air flow tube 121, a fixed shaft 122, and a plurality of swing blades 123.
  • the fixed shaft 122 is close to the outlet end of the primary air pulverized coal air flow tube 121, and the plurality of openings
  • the rotating blade 123 connects the inner wall of the primary air pulverized coal airflow pipe 121 and the fixed shaft 122, and is used to separate the primary air pulverized coal airflow into a dense pulverized coal airflow and a light pulverized coal airflow.
  • the fixed shaft 122 is used to fix each swing blade 123.
  • the turning blade 123 can cause the primary air pulverized coal airflow passing through it to make a rotating flow.
  • the primary air pulverized coal airflow flows in from the end of the primary air pulverized coal airflow pipe 121 located outside the pre-combustion housing 110, and flows along a straight line at the initial stage of entering the primary air pulverized coal airflow pipe 121. After passing through the turning blades 123, under the action of the turning blades 123, the primary air pulverized coal air flow is transformed from a linear flow to a high-speed rotating flow.
  • the pulverized coal air flow further flows in the primary air pulverized coal air flow pipe 121, and is respectively output through the concentration output structure 130 to form a dense pulverized coal air flow and a light pulverized coal air flow, so that the concentrated pulverized coal air flow flows into the pre-combustion chamber 111 in the reverse direction, and the light pulverized coal air flow
  • the light pulverized coal gas flow pipe 132 in the density output structure 130 flows into the pre-combustion chamber 111 in a straight direction.
  • the primary pulverized coal air flow can be concentrated, so that the concentration of the pulverized coal in the concentrated pulverized coal air flow is increased to more than twice that before the concentration, which is beneficial to reduce the combustion of different coal types.
  • the fire heat is required to make this part of the pulverized coal burn in advance to form the main flame, which heats and ignites the light pulverized coal flow and other unfired pulverized coal particles.
  • the primary air pulverized coal gas flow after the primary air pulverized coal gas flow is concentrated, it can also achieve effective pulverized coal concentration and grading combustion, which is conducive to forming a strong reduction zone in the pulverized coal combustion flame, so that a large amount of N elements released during the pulverized coal combustion process are transferred to NH 3 or N 2 conversion, inhibit NO x production.
  • the density output structure 130 includes a backflow baffle 131 and a light coal pulverized coal gas flow pipe 132 passing through the backflow baffle 131.
  • the backflow baffle 131 is located at the outlet end of the primary air pulverized coal gas flow pipe 121.
  • the surface of the backflow baffle 131 facing the primary air pulverized coal gas flow pipe 121 has a backflow groove 1311 which is used to guide the concentrated pulverized coal gas flow to the pre-combustion.
  • the shape of the inner wall of the return groove 1311 is linear and/or curved; the inner wall of the return groove 1311 and the outer wall of the primary air pulverized coal gas flow pipe are enclosed to form a dense coal pulverized coal air flow channel 133 with a circular cross-sectional shape for supplying dense coal
  • the powder airflow flows in the reverse direction.
  • One end of the light coal pulverized coal air flow pipe 132 extends into the middle area of the outlet end of the primary air pulverized coal air flow pipe 121 for outputting the light coal pulverized coal air flow in the primary air pulverized coal air flow pipe 121.
  • the low pulverized coal concentration air flow in the central area is directly facing the light coal pulverized coal air flow pipe 132.
  • the airflow pipe 132 is sprayed out in a direct current, thereby forming a light coal powder airflow.
  • the airflow is facing the return groove 1311 of the return baffle 131.
  • the pulverized coal gas flow of the primary air is injected into the pre-combustion chamber 111 in the reverse direction along the outer wall of the primary air pulverized coal gas flow pipe 121, thereby forming a reversely injected concentrated pulverized coal flow.
  • the primary air pulverized coal gas flow pipe 121 is arranged adjacent to the first-stage recirculation zone F.
  • the concentrated pulverized coal gas flow can be made to flow close to the first-stage recirculation zone F, and is affected by the direct heat radiation of the high-temperature first-stage recirculation zone F, which is beneficial to the temperature rise and ignition of the concentrated pulverized coal gas flow. Because the concentrated pulverized coal air flow is injected into the pre-combustion chamber 111 at a position near the first-stage recirculation zone F, the concentrated pulverized coal air flow is more likely to be entrained into the first-stage recirculation zone F during the flow.
  • the swirling combustion in the first-stage recirculation zone F releases heat, and then flows through the recirculation baffle 131 and is ejected from the pre-combustion chamber 111.
  • the primary air pulverized coal airflow flows in the primary air pulverized coal airflow pipe 121, and enters the pre-combustion chamber 111 through the return baffle 131.
  • the primary air pulverized coal airflow can prevent the primary air coal from entering the pre-combustion chamber 111.
  • the powder air pipe 121 and the return baffle 131 are cooled to achieve the effect of cooling and protection.
  • the bottom of the reflux tank 1311 is arc-shaped, and the side wall of the reflux tank 1311 is linear.
  • annular dense coal gas flow channel 133 with a U-shaped cross section is formed, which facilitates the reverse flow of the pulverized coal gas flow.
  • the pulverized coal gas flow pipe 132 is a straight-tube type of pulverized coal gas flow channel.
  • the primary air pulverized coal gas flow pipe 121 and the return baffle 131 are located on the central axis of the pre-combustion chamber 111.
  • the fixed shaft 122 is located on the central axis of the primary air pulverized coal gas flow pipe 121.
  • the backflow baffle 131 is arranged in a conical shape, and the cross-sectional dimension of the backflow baffle 131 toward the end of the primary air pulverized coal gas flow pipe 121 is smaller than the cross section of the backflow baffle 131 at the end of the primary air pulverized coal gas flow pipe 121 size.
  • a low pressure zone can be formed on the side of the backflow baffle 131 away from the primary air pulverized coal gas flow pipe 121.
  • the density output structure 130 includes a fixed rib 134 connected to the return baffle 131 and the primary air pulverized coal air flow pipe 121. This can ensure that the backflow baffle 131 is reliably fixed to the outlet end of the primary air pulverized coal gas flow pipe 121.
  • the amount of pulverized coal in the light pulverized coal air flow accounts for 10% to 20% of the total pulverized coal content, and the air volume in the light pulverized coal air flow accounts for one time.
  • the pulverized coal air flow is 60% to 70% of the total air volume; the pulverized coal air flow accounts for 80% to 90% of the total pulverized coal volume, and the air volume in the pulverized coal air flow accounts for the total air volume in the primary air pulverized coal air 30%-40%.
  • the internal secondary air structure 140 includes a strong-rotation internal secondary air component 141, a weak-rotation internal secondary air component 142, and a direct-current internal secondary air channel 143.
  • the strong-rotation internal secondary air component 141 is sleeved in The primary air pulverized coal structure 120 outside the pre-combustion housing 110, the weak-rotation internal secondary air assembly 142 is set in the strong-cyclone secondary air assembly 141, and the DC internal secondary air channel 143 is set in the weak-cyclone secondary air Component 142.
  • the tangential rotation speed of the secondary air component 141 in the strong rotation, the secondary air component 142 in the weak rotation, and the secondary air passage 143 in the direct current is gradually reduced.
  • the primary air pulverized coal structure 120, the strong-rotation internal secondary air component 141, the weak-rotation internal secondary air component 142, and the direct-current internal secondary air passage 143 are arranged from the inside to the outside, and the strong-rotation internal secondary air component 141 , The weak rotation internal secondary air component 142 and the direct current internal secondary air passage 143 are arranged in close proximity from the inside to the outside.
  • the internal secondary air is divided into three layers.
  • the rotation intensity of the internal secondary air delivered by the strong internal secondary air component 141 is greater than the rotation intensity of the internal secondary air delivered by the weak internal secondary air component 142, and the direct current internal secondary air channel 143 delivers direct current internal secondary air .
  • the strong cyclone internal secondary air component 141 transports the strong cyclone secondary air
  • the weak cyclone secondary air assembly 142 transports the weak cyclone secondary air
  • the DC internal secondary air passage 143 transports the DC internal secondary air.
  • the tapered section 112 has a certain The angle of inclination, the internal secondary air flow in the pre-combustion chamber 111 from top to bottom, due to the gradual expansion of the air flow area, the air flow velocity decreases, while the static pressure gradually rises, the above two reasons work together to make the internal During the flow of the secondary air in the pre-combustion chamber 111, part of the internal secondary air flows into the low pressure zone in the reverse direction, thereby forming the first-stage recirculation zone F.
  • the strong rotation internal secondary air assembly 141 includes a strong rotation internal secondary air channel 1411 and a strong rotation axial blade 1412 arranged in the strong rotation internal secondary air channel 1411, and the strong rotation axial blade 1412 is used for In this way, the internal secondary air in the strong swirl internal secondary air passage 1411 generates a tangential rotation speed.
  • the range of the outlet angle ⁇ of the forced rotation axial blade 1412 is 50°-80°.
  • the outlet angle ⁇ of the strong-rotation axial blade 1412 is relatively large, which can cause the internal secondary air flowing through it to generate a relatively large tangential rotation speed.
  • the forced rotation axial blade 1412 is an axial blade.
  • the weak-swirl secondary air assembly 142 includes a weak-swirl secondary air passage 1421 and a weak-swirl axial blade 1422 arranged in the weak-swirl secondary air passage 1421.
  • the weak-swirl axial blade 1422 is used for Therefore, the internal secondary air in the weak rotation internal secondary air passage 1421 generates a tangential rotation speed.
  • the range of the outlet angle ⁇ of the weak-rotation axial blade 1422 is 20°-50°.
  • the outlet angle ⁇ of the weak-rotation axial blade 1422 is small, which can cause the internal secondary air flowing through it to generate a small tangential rotation speed.
  • the weak-rotation axial blade 1422 is an axial blade.
  • the direct current secondary air passage 143 is sleeved in the weak rotation inner secondary air passage 1421 through a supporting rib 1431, and the supporting rib 1431 is flat to avoid generating a tangential rotation speed of the internal secondary air.
  • a total of three layers of strong internal secondary air component 141, weak internal secondary air component 142, and DC internal secondary air passage 143 are used to inject internal secondary air into the pre-combustion chamber 111.
  • the internal secondary air can be adjusted flexibly.
  • the air volume distribution between the secondary air flows adjusts the size of the return zone in the pre-combustion chamber 111 and the combustion state of the pulverized coal, which increases the flexible adjustment capability of the burner, which is beneficial to the flexible adjustment of the ignition and stable combustion of the pulverized coal under different load and coal types. .
  • it also increases the ability to flexibly adjust the suppression of NO x production.
  • the multi-stage backflow reverse injection swirl flow pulverized coal burner 100 further includes an annular connecting body 160, which is located between the secondary air component 141 in the strong swirl and the primary air pulverized coal structure 120, and The secondary air component 141 and the primary air pulverized coal structure 120 are connected and fixed.
  • the annular connecting body 160 can make a certain distance between the secondary air component 141 and the primary air pulverized coal structure 120 in the strong rotation, so as to facilitate the formation of the first-stage reflux zone F in the pre-combustion chamber 111.
  • the direct-current internal secondary air passage 143 conveys the direct-current internal secondary air along the inner wall of the pre-combustion housing 110, which can maintain an oxidizing atmosphere in the area near the inner wall of the pre-combustion housing 110 and avoid unburned coal particles or molten ore.
  • the substance reaches the wall area and causes the wall to coke.
  • the DC internal secondary air in the inner wall area of the pre-combustion housing 110 can also play a role in cooling and protecting the pre-combustion housing 110.
  • the outer secondary air structure 150 is located on the outside of the pre-combustion housing 110 and is used to convey the outer secondary air. During the flow of the external secondary air, the heat in the inner wall area of the pre-combustion housing 110 can be taken away, and the inner wall of the pre-combustion housing 110 can be further cooled and protected.
  • the outer secondary air structure 150 includes an outer secondary air inlet channel 151, an outer secondary air outlet channel 152, and tangential blades 153, and the outer secondary air inlet channel 151 and the outer secondary air outlet channel 152 are formed
  • the tangential blades 153 are connected and connected in a stepped manner, and the tangential blades 153 are arranged at the junction of the outer secondary air inlet channel 151 and the outer secondary air outlet channel 152.
  • the tangential blades 153 are used to rotate the external secondary air flowing therethrough at a high speed.
  • the external secondary air flows in from the external secondary air inlet channel 151, and is affected by the tangential blades 153, which can cause the external secondary air entering the external secondary air outlet channel 152 to produce high-speed rotation, and the external secondary air outlet channel 152 high-speed rotating jet.
  • the high-speed rotating and sprayed external secondary air helps to form a low-pressure zone at the exit of the pre-combustion chamber 111, thereby forming a third-stage return zone N, which further promotes the unburned pulverized coal ejected from the pre-combustion chamber 111 The burnout and steady burning.
  • the pulverized coal particles in different combustion stages are heated, which is beneficial to different coal types and load conditions.
  • the pulverized coal catches fire, burns steadily and burns out.
  • the range of the exit angle ⁇ of the tangential blade 153 is 15°-40°.
  • the tangential blade 153 is a tangential blade.
  • the outer secondary air structure 150 further includes a separation ring 154 which is disposed at the end of the outer secondary air outlet channel 152 and located on the outer wall of the flaring section 113.
  • the separating ring 154 can make the flame sprayed from the pre-combustion chamber 111 and the external secondary air space a certain distance, thereby delaying the mixing between the external secondary air and the unburned coal in the flame, and prolonging the pulverized coal in the reducing atmosphere combustion time, to suppress NO x generation.
  • the primary air pulverized coal airflow enters the primary air pulverized coal airflow pipe 121, and flows along a straight line at the initial stage of entering the primary air pulverized coal airflow pipe 121. After flowing through the turning blade 123, it is acted by the turning blade 123, The linear flow of the primary air pulverized coal air flow is transformed into a rotating flow.
  • the inner wall of the return groove 1311 and the outer wall of the primary air pulverized coal airflow pipe 121 form an annular concentrated
  • the pulverized coal air flow channel 133 after flowing through the concentrated pulverized coal air flow channel 133, is guided by the return groove 1311 and is injected into the pre-combustion chamber 111 in the reverse direction along the outer wall of the primary air pulverized coal air flow pipe 121. Thereby, a reverse jet of concentrated coal powder flow is formed.
  • the internal secondary air is divided into three layers, which are respectively entered by a strong internal secondary air component 141, a weak internal secondary air component 142, and a direct current internal secondary air passage 143.
  • a strong internal secondary air component 141 a weak internal secondary air component 142
  • a direct current internal secondary air passage 143 a direct current internal secondary air passage 143.
  • the air flow forms a low pressure area in the central area of the rotating air flow during the high-speed rotation flow process.
  • the pre-combustion housing 110 The inner wall has a certain inclination angle. During the continuous flow of the internal secondary air flow from top to bottom in the pre-combustion chamber 111, due to the gradual expansion of the flow area of the air flow, the flow velocity of the air flow is reduced, and the static pressure is gradually increased.
  • the external secondary air flows in from the external secondary air inlet channel 151, and after passing through the tangential blades 153, the external secondary air rotates at a high speed after entering the external secondary air outlet channel 152, and flows from the external secondary air outlet channel 152 high-speed rotating spray, the high-speed rotating spray of the external secondary air helps to form a third-stage recirculation zone N at the exit of the pre-combustion housing 110, forming a high-temperature return flue gas at the exit of the pre-combustion chamber 111, It further promotes the burn-out and stable combustion of the unburned pulverized coal ejected from the pre-combustion chamber 111.

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Abstract

一种多级回流逆喷式旋流煤粉燃烧器（100），包括：预燃壳体（110），预燃壳体（110）具有预燃室（111）以及位于预燃室（111）一侧的壳体出口；一次风煤粉结构（120），用于将一次风煤粉气流分离成浓煤粉气流及淡煤粉气流；浓淡输出结构（130），用于输出所述淡煤粉气流，并阻挡浓煤粉气流使所述浓煤粉气流逆向流动至预燃室（111）；内二次风结构（140），用于向预燃室（111）输入内二次风，使预燃室（111）形成第一级回流区，以及在浓淡输出结构（130）远离一次风煤粉结构（120）的一端形成第二级回流区；以及外二次风结构（150），用于输送外二次风，使壳体（110）出口处形成第三级回流区。一次风煤粉气流经过浓缩与分离后，采用三级回流区进行燃烧，有利于不同煤种及负荷条件下煤粉的着火、稳燃及燃尽，同时降低氮氧化物生成。

Description

多级回流逆喷式旋流煤粉燃烧器
相关申请
本申请要求2019年04月10日申请的，申请号为2019102839216，名称为“多级回流逆喷式旋流煤粉燃烧器”的中国专利申请的优先权，在此将其全文引入作为参考。
技术领域
本申请涉及煤粉燃烧设备技术领域，特别是涉及一种多级回流逆喷式旋流煤粉燃烧器。
背景技术
在我国，燃煤工业锅炉是除电站锅炉以外的主要煤燃烧使用设备。传统燃煤工业锅炉以层燃型炉排炉和链条炉为主，即将块状煤置于固定或移动的炉排上形成燃料层，空气从炉排底部通入，流过燃料层进行燃烧反应。受燃烧空间及反应有效面积所限，该炉型普遍存在锅炉热效率较低的问题。
近年来，随着煤粉加工、运输、存储和燃烧技术的不断发展，煤粉室燃方式逐步替代煤粉层燃，在燃煤锅炉中得到广泛的应用。该种方式采用空气携载煤粉颗粒喷入炉膛进行悬浮燃烧，加强气固混合与接触，提高锅炉的燃烧效率和热效率。但相比电站锅炉，中小型工业锅炉在实际运行过程中存在煤粉特性相差大、负荷调节范围宽的运行特点。但是，目前工业煤粉锅炉的设计准则大部分基于特定选用煤种及满负荷工况，造成在锅炉改用(混用)其他煤种及低负荷运行时，出现燃烧稳定性差、机械不完全燃烧损失大、NO x排放量高等诸多问题。
随着我国对环保问题的逐步重视，现有工业煤粉锅炉燃烧技术难以满足日益严苛的污染物排放标准。开发应用于工业煤粉锅炉的高效、低NO x生成、煤种适应性强及低负荷稳燃能力强的煤粉燃烧设备已成为行业亟需。
申请内容
基于此，有必要针对目前工业煤粉锅炉存在的煤粉燃尽及低负荷稳燃能力差与NO x排放量高的问题，提供一种多级回流逆喷式旋流煤粉燃烧器。
上述目的通过下述技术方案实现：
一种多级回流逆喷式旋流煤粉燃烧器，包括：
预燃壳体，所述预燃壳体具有预燃室以及位于所述预燃室一侧的壳体出口；
一次风煤粉结构，穿过所述预燃壳体伸入所述预燃室，用于将一次风煤粉气流分离成浓煤粉气流及淡煤粉气流，且所述一次风煤粉结构的出口端朝向所述壳体出口延伸；
浓淡输出结构，设置于所述一次风煤粉结构的出口端，所述浓淡输出结构用于输出所述淡煤粉气流，并阻挡所述浓煤粉气流使所述浓煤粉气流逆向流动至所述预燃室；
内二次风结构，设置于预燃壳体上，并位于所述一次风煤粉结构的周侧，所述内二次风结构用于向所述预燃室输入内二次风，使所述预燃室形成第一级回流区，以及在所述浓淡输出结构远离所述一次风煤粉结构的一端形成第二级回流区；以及
外二次风结构，套设于所述预燃壳体的外侧，用于输送外二次风，使所述壳体出口处形成第三级回流区。
在其中一个实施例中，所述预燃壳体包括锥形段以及与所述锥形段连接的所述扩口段，所述扩口段远离所述锥形段的一端为所述预燃壳体的壳体出口；
所述扩口段的倾斜角度大于所述锥形段的倾斜角度。
在其中一个实施例中，所述锥形段的倾斜角度α的范围为0°＜α≤20°；
所述扩口段的倾斜角度β的范围为20°～50°。
在其中一个实施例中，所述一次风煤粉结构包括一次风煤粉气流管、固定轴以及多个启旋叶片，所述固定轴靠近所述一次风煤粉气流管的出口端，多个所述启旋叶片连接所述一次风煤粉气流管的内壁与所述固定轴，用于使所述一次风煤粉气流分离为所述浓煤粉气流与所述淡煤粉气流。
在其中一个实施例中，所述浓淡输出结构包括回流挡板以及贯穿所述回流挡板的淡煤粉气流管；
所述回流挡板位于所述一次风煤粉气流管的出口端，所述回流挡板朝向所述一次风煤粉气流管的表面具有回流槽，所述回流槽用于引导所述浓煤粉气流逆向流动至所述预燃室，所述回流槽内壁的形状为直线型和/或曲线型；所述回流槽的内壁与所述一次风煤粉气流管的外壁围设成截面形状为环形的浓煤粉气流通道，供所述浓煤粉气流逆向流动；
所述淡煤粉气流管的一端伸入所述一次风煤粉气流管的出口端的中部区域，用于输出所述一次风煤粉气流管中的所述淡煤粉气流。
在其中一个实施例中，所述回流挡板呈锥形设置，且所述回流挡板朝向所述一次风煤粉气流管一端的截面尺寸小于所述回流挡板远离所述一次风煤粉气流管一端的截面尺寸；
所述浓淡输出结构包括固定筋，所述固定筋连接所述回流挡板与所述一次风煤粉气流管。
在其中一个实施例中，所述内二次风结构包括强旋内二次风组件、弱旋内二次风组件 以及直流内二次风通道，所述强旋内二次风组件套设于所述一次风煤粉结构，所述弱旋内二次风组件套设于所述强旋内二次风组件，所述直流内二次风通道套设于所述弱旋内二次风组件；
所述强旋内二次风组件、所述弱旋内二次风组件、所述直流内二次风通道输送内二次风的切向旋转速度逐渐减小。
在其中一个实施例中，所述强旋内二次风组件包括强旋内二次风通道以及设置于所述强旋内二次风通道中的强旋轴向叶片，所述强旋轴向叶片用于使所述强旋内二次风通道中内二次风产生切向旋转速度。
在其中一个实施例中，所述强旋轴向叶片的出口角度θ的范围为50°～80°。
在其中一个实施例中，所述弱旋内二次风组件包括弱旋内二次风通道以及设置于所述弱旋内二次风通道中的弱旋轴向叶片，所述弱旋轴向叶片用于使所述弱旋内二次风通道中内二次风产生切向旋转速度。
在其中一个实施例中，所述弱旋轴向叶片的出口角度δ的范围为20°～50°。
在其中一个实施例中，所述多级回流逆喷式旋流煤粉燃烧器还包括环形连接体，所述环形连接体位于所述强旋内二次风组件与所述一次风煤粉结构之间，并连接固定所述强旋内二次风组件与所述一次风煤粉结构。
在其中一个实施例中，所述外二次风结构包括外二次风入口通道、外二次风出口通道以及切向叶片，所述外二次风入口通道与所述外二次风出口通道呈阶梯状连接并连通，所述切向叶片设置于所述外二次风入口通道与所述外二次风出口通道的连接处。
在其中一个实施例中，所述切向叶片的出口角度γ的范围为15°～40°。
在其中一个实施例中，所述外二次风结构还包括分隔环，所述分隔环设置于所述外二次风出口通道的端部，并位于所述扩口段的外壁。
采用上述技术方案后，本申请至少具有如下技术效果：
本申请的多级回流逆喷式旋流煤粉燃烧器，一次风煤粉结构将一次风煤粉气流分离成浓煤粉气流及淡煤粉气流，浓煤粉气流经过浓淡输出结构的阻挡后，逆向流入预燃室，并与内二次风共同作用在预燃室内形成第一级回流区，使得浓煤粉气流被卷吸进入第一级回流区，并燃烧放热；同时，由于回流挡板呈锥形设置，使在浓淡输出结构远离一次风煤粉结构的一侧形成第二级回流区，以对淡煤粉加热并点燃淡煤粉气流。而后，预燃室内部的气流以及未充分燃烧的煤粉从预燃壳体的壳体出口喷出，外二次风结构使外二次风气流在壳体出口形成第三级回流区，可以促进未燃尽的煤粉燃尽与稳燃，最后喷射到炉膛中。这样，一次风煤粉气流经过浓缩与分离后，采用三级回流区进行燃烧，有利于不同煤种及负 荷条件下煤粉的着火、稳燃及燃尽，同时，降低煤粉燃烧过程中的NO x生成。有效解决目前工业煤粉锅炉存在的煤粉燃尽及低负荷稳燃能力差与NO x排放量高的问题。
附图说明
图1为本申请一实施例的多级回流逆喷式旋流煤粉燃烧器的主视剖视图；
图2为图1所示的多级回流逆喷式旋流煤粉燃烧器的侧视图；
图3为图2所示的多级回流逆喷式旋流煤粉燃烧器在A-A处的剖视图；
图4为图1所示的多级回流逆喷式旋流煤粉燃烧器中强旋内二次风组件的立体图；
图5为图1所示的多级回流逆喷式旋流煤粉燃烧器中弱旋内二次风组件的立体图；
图6为图2所示的多级回流逆喷式旋流煤粉燃烧器在B-B处的剖视图；
图7为图1所示的多级回流逆喷式旋流煤粉燃烧器中预燃壳体安装切向叶片的立体图；
图8为图1所示的多级回流逆喷式旋流煤粉燃烧器中一次风煤粉结构的启旋叶片的立体图；
图9为图1所示的多级回流逆喷式旋流煤粉燃烧器的原理图。
其中：
100-多级回流逆喷式旋流煤粉燃烧器；110-预燃壳体；111-预燃室；112-锥形段；113-扩口段；120-一次风煤粉结构；121-一次风煤粉气流管；122-固定轴；123-启旋叶片；130-浓淡输出结构；131-回流挡板；1311-回流槽；132-淡煤粉气流管；133-浓煤粉气流通道；134-固定筋；140-内二次风结构；141-强旋内二次风组件；1411-强旋内二次风通道；1412-强旋轴向叶片；142-弱旋内二次风组件；1421-弱旋内二次风通道；1422-弱旋轴向叶片；143-直流内二次风通道；1431-支撑筋；150-外二次风结构；151-外二次风入口通道；152-外二次风出口通道；153-切向叶片；154-分隔环；160-环形连接体。
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下通过实施例，并结合附图，对本申请的多级回流逆喷式旋流煤粉燃烧器进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本申请，并不用于限定本申请。
本文中为部件所编序号本身，例如“第一”、“第二”等，仅用于区分所描述的对象，不具有任何顺序或技术含义。而本申请所说“连接”、“联接”，如无特别说明，均包括直接和间接连接(联接)。在本申请的描述中，需要理解的是，术语“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”等指示的方位或位 置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
在本申请中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
参见图1至图9，本申请提供了一种多级回流逆喷式旋流煤粉燃烧器100。该多级回流逆喷式旋流煤粉燃烧器100应用于工业煤粉锅炉中。本申请的多级回流逆喷式旋流煤粉燃烧器100可实现煤粉的浓淡分离、多级气流回流以及空气氛级燃烧，有利于不同煤种及负荷条件下的煤粉着火、稳燃与燃尽，同时，降低煤粉燃烧过程中的NO x生成。
在一实施例中，多级回流逆喷式旋流煤粉燃烧器100包括预燃壳体110、一次风煤粉结构120、浓淡输出结构130、内二次风结构140以及外二次风结构150。一次风煤粉结构120部分伸入预燃壳体110，并与预燃壳体110连通。浓淡输出结构130位于一次风煤粉结构120在预燃壳体110内的端部处。内二次风结构140在预燃壳体110的外侧套设于一次风煤粉结构120，并与预燃壳体110连通，外二次风结构150套设于预燃壳体110的外侧。
具体的，预燃壳体110具有预燃室111以及位于预燃室111一侧的壳体出口。一次风煤粉结构120穿过预燃壳体110伸入预燃室111，用于将一次风煤粉气流分离成浓煤粉气流及淡煤粉气流，且一次风煤粉结构120的出口端朝向壳体出口延伸。浓淡输出结构130设置于一次风煤粉结构120的出口端，浓淡输出结构130用于输出淡煤粉气流，并阻挡浓煤粉气流使浓煤粉气流逆向流动至预燃室111。内二次风结构140设置于预燃壳体110上，并位于一次风煤粉结构120的周侧。内二次风结构140用于向预燃室111输入内二次风，使在预燃室111内形成第一级回流区F，以及在浓淡输出结构130远离一次风煤粉结构120的一端形成第二级回流区M。外二次风结构150套设于预燃壳体110的外侧，用于输送外二次风，使壳体出口处形成第三级回流区N。
一次风煤粉结构120将一次风煤粉气流输入至预燃壳体110的预燃室111中。一次风煤粉结构120在输入一次风煤粉气流的过程中，会将一次风煤粉气流进行浓淡分离形成浓煤粉气流与淡煤粉气流。分离后的浓煤粉气流与淡煤粉气流从一次风煤粉结构120流入预燃室111时，会通过浓淡输出结构130沿着不同方向流入预燃室111。浓煤粉气流进入浓淡输出结构130后，会受浓淡输出结构130阻挡，使得浓煤粉气流逆向流动。也就是说， 浓煤粉气流在预燃室111中，沿着与流动方向相反的方向流动，可以理解的，这里的流动方向是指一次风煤粉气流进入预燃室111的方向。而淡煤粉气流经过浓淡输出结构130后继续沿着流动方向流动。
同时，内二次风通过内二次风结构140在一次风煤粉结构120的周侧流入预燃室111，内二次风在流动过程中，与逆向流动的浓煤粉气流共同作用，会在预燃室111中形成第一级回流区F。由于浓煤粉气流在逆向流动过程中容易被卷吸到第一级回流区F内，使浓煤粉气流在第一级回流区F内回旋燃烧放热形成高温气流，而后流经浓淡输出结构130并由预燃室111的壳体出口喷出。并且，高温气流流经浓淡输出结构130时，会在浓淡输出结构130远离一次风煤粉结构120的一侧形成第二级回流区M，这部分回流的高温气流与由浓淡输出结构130喷出的淡煤粉气流相遇，将促进淡煤粉气流的升温，加热并点燃淡煤粉气流。
而后，预燃室111内部气流及未燃尽煤粉颗粒由预燃室111的壳体出口喷出。此时，外二次风结构150在预燃壳体110的外侧输入外二次风，在预燃室111的壳体出口处形成第三级回流区N，进而使得多级回流逆喷式旋流煤粉燃烧器100出口处同样产生高温回流烟气，进一步促进由预燃室111喷出的未燃尽煤粉的燃尽及稳燃。并且，煤粉燃烧初期所需的氧量由内二次风结构140、外二次风结构150分两级依次供给，使煤粉始终保持在还原性气氛下燃烧，从而降低煤粉燃烧过程中的NO x生成。
这样，一次风煤粉气流经过浓缩与分离后，采用三级回流区进行燃烧，有利于不同煤种及负荷条件下煤粉的着火、稳燃及燃尽，同时，降低煤粉燃烧过程中的NO x生成。有效解决目前工业煤粉锅炉存在的煤粉燃尽及低负荷稳燃能力差与NO x排放量高的问题。
在一实施例中，预燃壳体110包括锥形段112。沿一次风煤粉结构120中一次风煤粉气流的流动方向，锥形段112的截面尺寸逐渐增加。这样，由于靠近一次风煤粉结构120的旋转内二次风会带动一次风煤粉气流流动，在旋转气流的中心区域形成低压区，加之，预燃壳体110的锥形段112的侧壁具有一定倾斜角度，内二次风气流在预燃壳体110内自上而下的流动过程中，由于气流流动面积逐渐扩大，使气流流速降低，同时静压逐渐升高，以上两个原因共同作用使内二次风在预燃室111内流动过程中，部分内二次风反向流入低压区，从而在预燃室111内形成第一级回流区F。
在一实施例中，预燃壳体110还包括与锥形段112连接的扩口段113，扩口段113远离锥形段112的一端为预燃壳体110的壳体出口。扩口段113的截面尺寸沿一次风煤粉结构120中一次风煤粉气流的流动方向逐渐增大。
在一实施例中，扩口段113的倾斜角度大于锥形段112的倾斜角度。进一步地，锥形 段112的倾斜角度α的范围为0°＜α≤20°。扩口段113的倾斜角度β的范围为20°～50°。
在一实施例中，一次风煤粉结构120包括一次风煤粉气流管121、固定轴122以及多个启旋叶片123，固定轴122靠近一次风煤粉气流管121的出口端，多个启旋叶片123连接一次风煤粉气流管121的内壁与固定轴122，用于使一次风煤粉气流分离为浓煤粉气流与淡煤粉气流。固定轴122用于固定各个启旋叶片123。启旋叶片123可以使经过其的一次风煤粉气流做旋转流动。
一次风煤粉气流从一次风煤粉气流管121位于预燃壳体110外侧的一端流入，在进入一次风煤粉气流管121内的初期沿着直线流动。经过启旋叶片123后，受启旋叶片123的作用，将一次风煤粉气流由直线流动转变为高速的旋转流动。在一次风煤粉气流高速旋转过程中，由于煤粉颗粒密度大，自身受到的离心力作用大，而被甩向一次风煤粉气流管121的内壁附近，从而使一次风煤粉气流管121内壁附近的煤粉浓度高，而位于中心区域的煤粉浓度低。煤粉气流在一次风煤粉气流管121中进一步流动，并经过浓淡输出结构130分别输出形成浓煤粉气流与淡煤粉气流，使得浓煤粉气流逆向流入预燃室111，淡煤粉气流经浓淡输出结构130中的淡煤粉气流管132沿直线方向流入预燃室111。
可以理解的，一次风煤粉气流经过启旋叶片123后，可以使得一次煤粉气流浓缩，这样浓煤粉气流中煤粉浓度增大至浓缩前的2倍以上，有利于降低不同煤种燃烧所需着火热，使这部分煤粉提前燃烧形成主火焰，加热并点燃淡煤粉气流及其它未着火煤粉颗粒。同时，一次风煤粉气流经过浓缩后，还能实现有效的煤粉浓淡分级燃烧，有利于形成煤粉燃烧火焰内的强还原区，使煤粉燃烧过程中释放的N元素大量向NH 3或N 2转化，抑制NO x生成。
在一实施例中，浓淡输出结构130包括回流挡板131以及贯穿回流挡板131的淡煤粉气流管132。回流挡板131位于一次风煤粉气流管121的出口端，回流挡板131朝向一次风煤粉气流管121的表面具有回流槽1311，回流槽1311用于引导浓煤粉气流逆向流动至预燃室111，回流槽1311内壁的形状为直线型和/或曲线型；回流槽1311的内壁与一次风煤粉气流管的外壁围设成截面形状为环形的浓煤粉气流通道133，供浓煤粉气流逆向流动。淡煤粉气流管132的一端伸入一次风煤粉气流管121的出口端的中部区域，用于输出一次风煤粉气流管121中的淡煤粉气流。
随着煤粉气流的进一步流动，在到达一次风煤粉气流管121的出口时，由于中心区域的低煤粉浓度气流正对淡煤粉气流管132，使该部分煤粉气流由淡煤粉气流管132直流喷出，从而形成淡煤粉气流。与此同时，由于一次风煤粉气流管121内壁附近的高煤粉浓度气流正对回流挡板131的回流槽1311。由于回流槽1311的内壁与一次风煤粉气流管121 的外壁围设成浓煤粉气流通道133，高浓度煤粉气流会进入浓煤粉气流通道133。受回流槽1311内壁的导向作用，沿着一次风煤粉气流管121的外壁反向喷入预燃室111内，从而形成反向喷射的浓煤粉气流。
可以理解的，一次风煤粉气流管121与第一级回流区F相邻设置。这样，可以使得浓煤粉气流紧邻第一级回流区F流动，受高温的第一级回流区F的直接热辐射影响，有利于浓煤粉气流的升温与着火。由于浓煤粉气流在临近第一级回流区F位置喷入预燃室111，使浓煤粉气流在流动过程中更容易被卷吸到第一级回流区F内，浓煤粉气流在第一级回流区F内回旋燃烧放热，而后流经回流挡板131并由预燃室111喷出。并且，一次风煤粉气流在一次风煤粉气流管121中流动，并经由回流挡板131进入预燃室111，一次风煤粉气流在进入预燃室111的过程中，可以对一次风煤粉气流管121以及回流挡板131进行冷却，以达到降温保护的作用。
示例性地，回流槽1311的底部呈弧形设置，回流槽1311的侧壁呈直线型。这样，回流槽1311的内壁与一次风煤粉气流管121的外壁之间形成具有U形截面的环状浓煤粉气流通道133，便于煤粉气流的反向流动。淡煤粉气流管132为具有直筒型的淡煤粉气流通道。
可选地，一次风煤粉气流管121与回流挡板131位于预燃室111的中轴线上。固定轴122位于一次风煤粉气流管121的中轴线上。
在一实施例中，回流挡板131呈锥形设置，且回流挡板131朝向一次风煤粉气流管121一端的截面尺寸小于回流挡板131远离所述一次风煤粉气流管121一端的截面尺寸。采用锥形的回流挡板131后，可以在回流挡板131远离一次风煤粉气流管121的一侧形成低压区。这样，第一级回流区F燃烧后产生的高温气流流经锥形的回流挡板131时，将在回流挡板131后方形成低压区，使部分高温气流在回流挡板131后方发生回流，形成第二级回流区M，这部分回流的高温气流与由回流挡板131的淡煤粉气流管132中部喷出的淡煤粉气流相遇，将促进淡煤粉气流的升温，加热并点燃淡煤粉气流。而后，预燃室111内部气流及未燃尽煤粉颗粒由预燃室111喷出。
在一实施例中，浓淡输出结构130包括固定筋134，固定筋134连接回流挡板131与一次风煤粉气流管121。这样可以保证回流挡板131可靠的固定于一次风煤粉气流管121的出口端。
可以理解的，通过一次风煤粉结构120对一次风煤粉气流进行浓淡分离后，淡煤粉气流中含粉量占总煤粉量的10％～20％，淡煤粉气流中风量占一次风煤粉气流中总风量的60％～70％；浓煤粉气流中含粉量占总煤粉量的80％～90％，浓煤粉气流中风量占一次风煤 粉气流中总风量的30％～40％。由于浓煤粉气流的煤粉浓度高，使自身着火热降低，有利于浓煤粉气流的着火，增强低负荷稳燃能力及煤种适应性。同时，煤粉气流在富燃料条件下燃烧，有利于减少NO x的生成。
在一实施例中，内二次风结构140包括强旋内二次风组件141、弱旋内二次风组件142以及直流内二次风通道143，强旋内二次风组件141套设于预燃壳体110外侧的一次风煤粉结构120，弱旋内二次风组件142套设于强旋内二次风组件141，直流内二次风通道143套设于弱旋内二次风组件142。强旋内二次风组件141、弱旋内二次风组件142、直流内二次风通道143输送内二次风的切向旋转速度逐渐减小。即一次风煤粉结构120、强旋内二次风组件141、弱旋内二次风组件142、直流内二次风通道143从内到外依次布置，并且，强旋内二次风组件141、弱旋内二次风组件142、直流内二次风通道143从内到外紧邻布置。
也就是说，内二次风分为三层。强旋内二次风组件141输送的内二次风的旋转强度大于弱旋内二次风组件142输送的内二次风的旋转强度，直流内二次风通道143输送直流的内二次风。这样，强旋内二次风组件141输送的内二次风喷入预燃室111时产生较大的切向旋转速度，弱旋内二次风组件142输送的内二次风喷入预燃室111时产生较小的切向旋转速度，直流内二次风通道143输送的内二次风无切向旋转速度，直流喷入预燃室111内。也就是说，强旋内二次风组件141输送强旋内二次风，弱旋内二次风组件142输送弱旋内二次风，直流内二次风通道143输送直流内二次风。
以上使整体内二次风喷入预燃室111后，形成在预燃室111中由内至外，内二次风气流旋转强度逐渐减小至零的速度分布。由于靠近一次风煤粉气流管121的内二次风气流具有较大的旋转切向速度，使气流在高速旋转流动过程中，在旋转气流中心区域形成低压区，加之，锥形段112具有一定倾斜角度，内二次风气流在预燃室111内由上至下的流动过程中，由于气流流动面积逐渐扩大，使气流流速降低，同时静压逐渐升高，以上两个原因共同作用使内二次风在预燃室111内流动过程中，部分内二次风反向流入低压区，从而形成第一级回流区F。
在一实施例中，强旋内二次风组件141包括强旋内二次风通道1411以及设置于强旋内二次风通道1411中的强旋轴向叶片1412，强旋轴向叶片1412用于使强旋内二次风通道1411中内二次风产生切向旋转速度。
在一实施例中，强旋轴向叶片1412的出口角度θ的范围为50°～80°。也就是说，强旋轴向叶片1412的出口角度θ较大，可以使流经其的内二次风产生较大的切向旋转速度。可选地，强旋轴向叶片1412为轴向叶片。
在一实施例中，弱旋内二次风组件142包括弱旋内二次风通道1421以及设置于弱旋内二次风通道1421中的弱旋轴向叶片1422，弱旋轴向叶片1422用于使弱旋内二次风通道1421中内二次风产生切向旋转速度。
在一实施例中，弱旋轴向叶片1422的出口角度δ的范围为20°～50°。也就是说，弱旋轴向叶片1422的出口角度δ较小，可以使流经其的内二次风产生较小的切向旋转速度。可选地，弱旋轴向叶片1422为轴向叶片。
可选的，直流内二次风通道143通过支撑筋1431套设于弱旋内二次风通道1421，并且，支撑筋1431为平板状，以避免使内二次风产生切向旋转速度。
采用强旋内二次风组件141、弱旋内二次风组件142、直流内二次风通道143共三层将内二次风喷入预燃室111内，可通过灵活调节各股内二次风气流间的风量分配调整预燃室111内回流区大小及煤粉燃烧状态，增加燃烧器的灵活调节能力，有利于在不同负荷及煤种条件下对煤粉着火及稳燃的灵活调节。同时，还增加了对抑制NO x生成的灵活调节能力。
在一实施例中，多级回流逆喷式旋流煤粉燃烧器100还包括环形连接体160，环形连接体160位于强旋内二次风组件141与一次风煤粉结构120之间，并连接固定强旋内二次风组件141与一次风煤粉结构120。环形连接体160可以使得强旋内二次风组件141与一次风煤粉结构120之间存在一定的间距，便于在预燃室111中形成第一级回流区F。
同时，直流内二次风通道143沿预燃壳体110的内壁输送直流内二次风，可以使近预燃壳体110的内壁区域保持氧化性气氛，避免未燃尽煤粉颗粒或熔融矿物质到达壁面区域造成壁面结焦。并且，预燃壳体110内壁区域的直流内二次风也能够起到对预燃壳体110的降温保护作用。
并且，外二次风结构150位于预燃壳体110的外侧，用于输送外二次风。外二次风在流动过程中，可以带走预燃壳体110内壁区域的热量，对预燃壳体110的内壁起到进一步的降温保护作用。
在一实施例中，外二次风结构150包括外二次风入口通道151、外二次风出口通道152以及切向叶片153，外二次风入口通道151与外二次风出口通道152呈阶梯状连接并连通，切向叶片153设置于外二次风入口通道151与外二次风出口通道152的连接处。切向叶片153用于使流经其的外二次风发生高速旋转。外二次风由外二次风入口通道151流入，受切向叶片153的作用，可以使进入外二次风出口通道152后的外二次风产生高速旋转，并由外二次风出口通道152高速旋转喷出。高速旋转喷出的外二次风有助于在预燃室111的壳体出口处形成低压区，从而形成第三级回流区N，进一步促进由预燃室111喷出的未燃 尽煤粉的燃尽与稳燃。
通过设置三级高温烟气回流即第一级回流区F、第二级回流区M、第三级回流区N，从而加热处于不同燃烧阶段的煤粉颗粒，有利于不同煤种及负荷条件下的煤粉着火、稳燃及燃尽。
在一实施例中，切向叶片153的出口角度γ的范围为15°～40°。可选地，切向叶片153为切向叶片。
在一实施例中，外二次风结构150还包括分隔环154，分隔环154设置于外二次风出口通道152的端部，并位于扩口段113的外壁。分隔环154可以使由预燃室111内喷出的火焰与外二次风间隔一定距离，从而推迟了外二次风与火焰中未燃尽煤粉间的混合，延长了煤粉在还原气氛下的燃烧时间，抑制NO x生成。
本申请的多级回流逆喷式旋流煤粉燃烧器100的工作原理如下：
一次风煤粉气流由一次风煤粉气流管121进入，在进入一次风煤粉气流管121内的初期沿着直线方向流动，在流经启旋叶片123后，受启旋叶片123的作用，将一次风煤粉气流的直线流动转变为旋转流动。在一次风煤粉气流高速旋转过程中，由于煤粉颗粒密度大，自身受到的离心力作用大，而被甩向一次风煤粉气流管121的内壁附近，从而使一次风煤粉气流管121内壁附近的煤粉浓度高，而位于中心区域的煤粉浓度低。随着煤粉气流的进一步流动，在到达一次风煤粉气流管121的出口端时，由于中心区域的低浓度煤粉气流正对淡煤粉气流管132，使该部分气流由淡煤粉气流管132直流喷出，从而形成淡煤粉气流。与此同时，由于一次风煤粉气流管121内壁附近的高浓度煤粉气流正对回流挡板131的回流槽1311，回流槽1311的内壁与一次风煤粉气流管121的外壁形成环形的浓煤粉气流通道133，使这部分气流在流经浓煤粉气流通道133后，受回流槽1311的导向作用，沿着一次风煤粉气流管121的外壁反向喷入预燃室111内，从而形成反向喷射的浓煤粉气流。
在预燃室111中，内二次风分三层，分别由强旋内二次风组件141、弱旋内二次风组件142及直流内二次风通道143进入。其中，一部分内二次风进入强旋内二次风通道1411后，由于强旋轴向叶片1412的出口角度大，使该部分内二次风在喷入预燃室111时产生较大的切向旋转速度；一部分内二次风进入弱旋内二次风通道1421后，由于弱旋轴向叶片1422的出口角度小，使该部分内二次风在喷入预燃室111时产生较小的切向旋转速度；另一部分内二次风进入直流内二次风通道143后，未受任何导向叶片的作用，直流喷入预燃室111内。以上使整体内二次风喷入预燃室111后，形成在预燃室111中由内至外，内二次风气流旋转强度逐渐减小至零的速度分布。
由于靠近一次风煤粉气流管121的内二次风气流具有较大的旋转切向速度，使气流在 高速旋转流动过程中，在旋转气流中心区域形成低压区，加之，预燃壳体110的内壁具有一定倾斜角度，内二次风气流在预燃室111内自上而下的持续流动过程中，由于气流流动面积逐渐扩大，使气流流速降低，同时静压逐渐升高，以上两个原因共同作用使内二次风在预燃室111内流动过程中，部分内二次风反向流入低压区，从而形成第一级回流区F。由于浓煤粉气流在临近第一级回流区F位置喷入，使浓煤粉气流在流动过程中更容易被卷吸到第一级回流区F内，浓煤粉气流在第一级回流区F内回旋燃烧放热，而后流经回流挡板131区域并由预燃室111喷出。
高温气流流经锥形的回流挡板131时，将在回流挡板131后方形成低压区，使部分高温气流在回流挡板131后方发生回流，形成第二级回流区M，这部分回流的高温气流与由回流挡板131中部喷出的淡煤粉气流相遇，将促进淡煤粉气流的升温，加热并点燃淡煤粉气流。而后，预燃室111内部气流及未燃尽煤粉颗粒由预燃室111喷出。此时，外二次风由外二次风入口通道151流入，经由切向叶片153后，外二次风在进入外二次风出口通道152后发生高速旋转，并由外二次风出口通道152高速旋转喷出，高速旋转喷出的外二次风有助于在预燃壳体110的壳体出口处形成第三级回流区N，形成预燃室111出口处的高温回流烟气，进一步促进由预燃室111喷出的未燃尽煤粉的燃尽及稳燃。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书的记载范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对本申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (10)

  1. 一种多级回流逆喷式旋流煤粉燃烧器，其特征在于，包括：
    预燃壳体，所述预燃壳体具有预燃室以及位于所述预燃室一侧的壳体出口；
    一次风煤粉结构，穿过所述预燃壳体伸入所述预燃室，用于将一次风煤粉气流分离成浓煤粉气流及淡煤粉气流，且所述一次风煤粉结构的出口端朝向所述壳体出口延伸；
    浓淡输出结构，设置于所述一次风煤粉结构的出口端，所述浓淡输出结构用于输出所述淡煤粉气流，并阻挡所述浓煤粉气流使所述浓煤粉气流逆向流动至所述预燃室；
    内二次风结构，设置于预燃壳体上，并位于所述一次风煤粉结构的周侧，所述内二次风结构用于向所述预燃室输入内二次风，使所述预燃室形成第一级回流区，以及在所述浓淡输出结构远离所述一次风煤粉结构的一端形成第二级回流区；以及
    外二次风结构，套设于所述预燃壳体的外侧，用于输送外二次风，使所述壳体出口处形成第三级回流区。
  2. 根据权利要求1所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述预燃壳体包括锥形段以及与所述锥形段连接的所述扩口段，所述扩口段远离所述锥形段的一端为所述预燃壳体的壳体出口；
    所述扩口段的倾斜角度大于所述锥形段的倾斜角度。
  3. 根据权利要求1所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述一次风煤粉结构包括一次风煤粉气流管、固定轴以及多个启旋叶片，所述固定轴靠近所述一次风煤粉气流管的出口端，多个所述启旋叶片连接所述一次风煤粉气流管的内壁与所述固定轴，用于使所述一次风煤粉气流分离为所述浓煤粉气流与所述淡煤粉气流。
  4. 根据权利要求3所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述浓淡输出结构包括回流挡板以及贯穿所述回流挡板的淡煤粉气流管；
    所述回流挡板位于所述一次风煤粉气流管的出口端，所述回流挡板朝向所述一次风煤粉气流管的表面具有回流槽，所述回流槽用于引导所述浓煤粉气流逆向流动至所述预燃室，所述回流槽内壁的形状为直线型和/或曲线型；所述回流槽的内壁与所述一次风煤粉气流管的外壁围设成截面形状为环形的浓煤粉气流通道，供所述浓煤粉气流逆向流动；
    所述淡煤粉气流管的一端伸入所述一次风煤粉气流管的出口端的中部区域，用于输出所述一次风煤粉气流管中的所述淡煤粉气流。
  5. 根据权利要求4所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述回流 挡板呈锥形设置，且所述回流挡板朝向所述一次风煤粉气流管一端的截面尺寸小于所述回流挡板远离所述一次风煤粉气流管一端的截面尺寸；
    所述浓淡输出结构包括固定筋，所述固定筋连接所述回流挡板与所述一次风煤粉气流管。
  6. 根据权利要求1所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述内二次风结构包括强旋内二次风组件、弱旋内二次风组件以及直流内二次风通道，所述强旋内二次风组件套设于所述一次风煤粉结构，所述弱旋内二次风组件套设于所述强旋内二次风组件，所述直流内二次风通道套设于所述弱旋内二次风组件；
    所述强旋内二次风组件、所述弱旋内二次风组件、所述直流内二次风通道输送内二次风的切向旋转速度逐渐减小。
  7. 根据权利要求6所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述强旋内二次风组件包括强旋内二次风通道以及设置于所述强旋内二次风通道中的强旋轴向叶片，所述强旋轴向叶片用于使所述强旋内二次风通道中内二次风产生切向旋转速度；
    所述强旋轴向叶片的出口角度θ的范围为50°～80°。
  8. 根据权利要求6所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述弱旋内二次风组件包括弱旋内二次风通道以及设置于所述弱旋内二次风通道中的弱旋轴向叶片，所述弱旋轴向叶片用于使所述弱旋内二次风通道中内二次风产生切向旋转速度；
    所述弱旋轴向叶片的出口角度δ的范围为20°～50°。
  9. 根据权利要求6所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述多级回流逆喷式旋流煤粉燃烧器还包括环形连接体，所述环形连接体位于所述强旋内二次风组件与所述一次风煤粉结构之间，并连接固定所述强旋内二次风组件与所述一次风煤粉结构。
  10. 根据权利要求2所述的多级回流逆喷式旋流煤粉燃烧器，其特征在于，所述外二次风结构包括外二次风入口通道、外二次风出口通道以及切向叶片，所述外二次风入口通道与所述外二次风出口通道呈阶梯状连接并连通，所述切向叶片设置于所述外二次风入口通道与所述外二次风出口通道的连接处；
    所述外二次风结构还包括分隔环，所述分隔环设置于所述外二次风出口通道的端部，并位于所述扩口段的外壁。
PCT/CN2020/082896 2019-04-10 2020-04-02 多级回流逆喷式旋流煤粉燃烧器 WO2020207318A1 (zh)

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