WO2011035604A1 - 一种煤粉燃烧器及具有该煤粉燃烧器的锅炉 - Google Patents

一种煤粉燃烧器及具有该煤粉燃烧器的锅炉 Download PDF

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WO2011035604A1
WO2011035604A1 PCT/CN2010/073201 CN2010073201W WO2011035604A1 WO 2011035604 A1 WO2011035604 A1 WO 2011035604A1 CN 2010073201 W CN2010073201 W CN 2010073201W WO 2011035604 A1 WO2011035604 A1 WO 2011035604A1
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WIPO (PCT)
Prior art keywords
pulverized coal
combustion chamber
internal combustion
boiler
furnace
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PCT/CN2010/073201
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English (en)
French (fr)
Inventor
王雨蓬
张经武
刘武成
张昀
伊磊
龚泽儒
程昌业
孙树翁
张超群
张玉斌
杨家驹
苗雨旺
崔星源
王雨勃
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烟台龙源电力技术股份有限公司
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Publication of WO2011035604A1 publication Critical patent/WO2011035604A1/zh

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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
    • 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 
    • F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
    • F23C5/08—Disposition of burners

Definitions

  • Pulverized coal burner and boiler having the same Pulverized coal burner and boiler having the same, the present application is filed on September 27, 2009, the Chinese Patent Office, the application number is 200910175071.4, the invention name is "a pulverized coal burner and has the pulverized coal
  • the priority of the Chinese patent application of the "Boiler of the Burner” is hereby incorporated by reference in its entirety.
  • the present invention relates to a pulverized coal combustion technology, and more particularly to a pulverized coal burner, and to a boiler having the pulverized coal burner. Background technique
  • the combustion process of a boiler consists of two phases: the first phase is the boiler ignition phase and the second phase is the normal combustion phase.
  • the first stage when the boiler is ignited, in order to ignite the pulverized coal and keep the pulverized coal burning and increase the temperature of the furnace, it is often necessary to put fuel into the combustion to ignite the pulverized coal and increase the temperature inside the furnace; After the temperature rises to a certain height, it enters the second stage of boiler combustion, the normal combustion stage.
  • the fuel In the normal combustion stage, the fuel is stopped, and after the pulverized coal enters the furnace, the high temperature flue gas radiant heat and convective heat in the furnace ignite, burn, and release heat.
  • the first deficiency is: In the normal combustion stage, in order to maintain the continuous combustion of pulverized coal, it is necessary to maintain a higher temperature in the furnace; only by maintaining a higher temperature in the furnace, the pulverized coal can rely on the radiant heat of the high-temperature flue gas in the furnace. Convective heat combustion keeps the burnout rate of pulverized coal. Therefore, in the initial stage of operation of the boiler, the burnout rate of the pulverized coal is very low due to the lower temperature in the furnace, which makes the boiler operation less efficient. Moreover, when the temperature in the furnace is below a certain point, the boiler cannot maintain its own continuous operation, and there is a defect that the combustion stability of the pulverized coal in the boiler is poor. Therefore, when the boiler is running at low load, fuel-assisted combustion is often required to keep the boiler running continuously.
  • the pulverized coal burner is actually only a fuel transmission component and cannot maintain the stability of pulverized coal combustion.
  • people mainly start from reducing the ignition heat of pulverized coal and improving the heating of fire.
  • Corresponding measures were taken to improve the stability of boiler pulverized coal combustion.
  • Reducing the ignition heat of pulverized coal is mainly achieved by improving the performance of primary air.
  • the main methods include: increasing the quality and concentration of pulverized coal of primary air powder; increasing the initial temperature of primary pulverized coal to increase the ignition of pulverized coal in the primary wind. Performance; In this technology, the representative ones are WR burners and PAX burners.
  • the technical measures to improve the heating of the fire mainly include: changing the organization or direction of the primary air flow of the pulverized coal burner, strengthening the ignition heating, improving the ignition performance of the pulverized coal; improving the contact area between the primary pulverized coal gas flow and the high temperature flue gas in the furnace Strong thermal and thermal exchanges
  • the following is a specific example to illustrate a technical solution to improve the way of heating.
  • the boiler includes a pre-combustion chamber pulverized coal burner and a boiler body, and the boiler body forms a furnace.
  • FIG. 1 is a schematic structural view of a pre-combustion chamber pulverized coal burner in the prior art.
  • the pulverized coal burner comprises a primary air duct 1, an axial swirling vane 2, a pre-combustion chamber 3, a pre-chamber outlet 4, and a pre-chamber outlet 4 communicating with a furnace of the boiler (not shown).
  • the working principle of the pulverized coal burner of the above structure is: the pulverized coal gas flow passes through the primary air duct 1, the primary air swirling air flow formed by the axial swirling vane 2, and is sent to the cylindrical pre-combustion chamber 3 at the primary air inlet. Under the action of the conical end cap, the restricted primary air swirling air flow is directed to the circumferential wall surface, and a large recirculation zone is formed in the center of the pre-combustion chamber 3, and the recirculation zone has a corresponding negative pressure.
  • the pre-combustion chamber 3 Under the negative pressure of the recirculation zone in the pre-combustion chamber 3, the pre-combustion chamber 3, the high-temperature flue gas in the furnace is returned to the primary air root through the pre-chamber outlet 4, and the pulverized coal entering the pre-chamber 3 is ignited. To achieve pre-combustion of the boiler, the pulverized coal after combustion is then burned into the furnace.
  • a carbon powder burning machine with low production cost, complete combustion and direct injection type disclosed in the Chinese patent document CN2580304Y is also known, and the carbon powder burning machine is arranged in the asphalt mixing tank.
  • a flame can be sprayed to incinerate or heat other articles.
  • the toner burner is burned with carbon powder. Material.
  • the toner burner comprises a body, an igniter and a mesh type fire interceptor; the body forms a forced ignition internal combustion chamber, and the forced ignition internal combustion chamber has an air inlet hole at the end to allow air to enter the forced ignition internal combustion chamber;
  • the igniter includes an electric shock rod, an outer ring tube and a gas tube. The toner enters the forced ignition internal combustion chamber through the outer ring tube, and the gas enters the forced ignition internal combustion chamber through the gas tube, and the electric hammer rod is used to ignite the gas; the fire interceptor is located Near the exit position of the forced ignition internal combustion chamber.
  • the working process of the toner burner comprises two stages, the first stage is an ignition start stage, in which the electric hammer ignites the gas, the gas ignites the carbon, and burns in the forced ignition internal combustion chamber;
  • the powder is ejected outward through the fire interceptor.
  • part of the carbon powder adheres to the fire interceptor to form a carbon powder fire; when the carbon powder attached to the fire interceptor reaches a certain amount, it enters a normal operation stage.
  • the carbon powder entering the forced ignition internal combustion chamber through the outer ring tube is ignited by the carbon powder fire attached to the fire interceptor, and is completely and fully burned in the external combustion chamber, thereby providing sufficient heat to ensure the spray.
  • the intensity of the flame is achieved, and the incineration of other items is achieved.
  • the technical scheme obtains sufficient fire by the fire interceptor to provide sufficient heating to ensure continuous combustion of the carbon powder; since the carbon powder is completely burned in the forced ignition internal combustion chamber, the heat of the carbon powder is released in the forced ignition internal combustion chamber Therefore, it cannot be applied on the boiler.
  • the second deficiency is:
  • the nitrogen element in the pulverized coal easily reacts with oxygen to form nitrogen oxides, thereby causing a large amount of nitrogen oxides in the boiler and lowering the environmental performance of the boiler.
  • Coal is a complex polymer hydrocarbon whose main components are: carbon, hydrogen, oxygen, nitrogen, sulfur, ash and moisture, wherein the nitrogen content is about 0.5% to 2.5%.
  • Decomposition generates fuel-type nitrogen oxides, which account for about 75%-90% of the total amount of nitrogen oxides produced during the combustion of all pulverized coal.
  • the traditional low-NOx combustion technology controls the fuel-type nitrogen oxides by appropriately reducing the furnace temperature to control the formation of thermal nitrogen oxides while creating a reductive reaction zone with a lower oxygen content in the furnace as much as possible.
  • the main realization of the amount of production is: 1) The overall air classification of the furnace. As shown in Fig. 2, the schematic diagram of the overall air classification low NOx combustion technology of the furnace is shown. In the lower part of the furnace, a reducing combustion zone A is formed, and an oxygen-rich combustion zone B is formed in the upper part of the furnace, and in the reducing combustion zone A, it is minimized.
  • the burning rate of the coal powder is ensured, and the operating efficiency of the boiler is ensured.
  • a technical scheme for reducing the nitrogen oxides by grading and grading is also provided.
  • the pulverized coal gas stream is subjected to concentration separation, and the boiler furnace is divided into two regions, and about 85% of the pulverized coal is used.
  • the first region having a higher oxygen content is sent to perform oxyfuel combustion to generate a large amount of nitrogen oxides; about 15% of the pulverized coal is sent to the second region having a lower oxygen content for reductive combustion; and the first region is The generated nitrogen oxides are fed into the second region, and the nitrogen oxides generated in the first region are reduced by reducing combustion to suppress the formation of nitrogen oxides and reduce the amount of nitrogen oxides emitted from the boiler.
  • the way to reduce the combustion zone in the furnace is to adjust the proportion of the pulverized coal gas stream, that is, to form a reducing reaction zone in a predetermined area by reducing the excess air ratio of the predetermined area.
  • reducing the excess air ratio can cause adverse effects on the performance of the boiler, reduce the burnout rate of the pulverized coal, increase the carbon content of the boiler fly ash, reduce the combustion efficiency of the boiler, and may also affect the combustion of the pulverized coal. Stability.
  • the above-mentioned adverse effects of the air ratio on the boiler require the addition of air to the boiler to meet the requirements for pulverized coal burnout.
  • the timing and replenishment of air enrichment become the key to the combustion performance of pulverized coal in the boiler.
  • the air supply should not be too late, and the amount of replenishment should not be too small.
  • This aspect limits the size of the reductive reaction zone and the degree of reductive combustion.
  • the effect of suppressing the formation of nitrogen oxides is weakened; on the other hand, in order to manufacture a reducing combustion zone, the combustion atmosphere of the pulverized coal is forcibly destroyed, and in short, the scope of the existing low NOx combustion technology is limited to In the boiler furnace, the role of suppressing the formation of nitrogen oxides is limited, and the combustion efficiency of the boiler is also reduced.
  • fuel-type nitrogen oxides account for a large proportion. Therefore, how to reduce the amount of fuel-type nitrogen oxides generated in the case of ensuring the operating efficiency of the boiler is a technical problem to be solved urgently.
  • a first object of the present invention is to provide a pulverized coal burner capable of improving the combustion stability of boiler pulverized coal, and at the same time, it is possible to reduce the amount of nitrogen oxides generated during operation of the boiler.
  • a second object of the present invention is to provide a boiler comprising the above pulverized coal burner.
  • the heat source is a continuous heat source to continuously ignite the coal powder.
  • the internal combustion chamber includes a deceleration inlet section that is in contact with the front end of the main combustion chamber, and the cross-sectional area of the deceleration inlet section is smaller than the cross-sectional area of the main combustion chamber.
  • the cross-sectional area of the deceleration inlet section is gradually increased in the flow direction of the pulverized coal gas stream.
  • the internal combustion chamber further includes an acceleration outlet section that is in contact with the rear end of the main combustion chamber; the cross-sectional area of the acceleration outlet section is smaller than the cross-sectional area of the main combustion chamber.
  • the cross-sectional area of the acceleration outlet section gradually decreases in the direction of flow of the pulverized coal gas stream.
  • the internal combustion chamber further includes an outlet adjustment section that is in contact with the rear end of the acceleration outlet section.
  • the cross-sectional areas of the front end and the rear end of the outlet adjustment section are equal.
  • the inner combustion chamber inner wall has a ceramic refractory layer.
  • the present invention further provides a boiler including a furnace body formed by the furnace body, and further comprising any of the above-mentioned pulverized coal burners; the outlet of the internal combustion chamber of the pulverized coal burner is in communication with the furnace, so as to facilitate The burning coal powder is allowed to enter the furnace to continue burning.
  • the pulverized coal burner provided by the present invention is not only a fuel delivery component, but also includes an internal combustion chamber for maintaining a pulverized coal gas flow inside thereof with a predetermined, relatively a small excess air ratio;
  • the main combustion chamber has a long cylindrical shape and has a predetermined length;
  • the heat source located in the internal combustion chamber is capable of igniting pulverized coal passing through the internal combustion chamber to cause the pulverized coal to undergo reductive combustion in the internal combustion chamber. Due to the above differences, the boiler having the pulverized coal burner can produce the following technical effects:
  • the heat source can ignite the pulverized coal passing through the internal combustion chamber, so that the pulverized coal passing through the internal combustion chamber is burned in the internal combustion chamber to form a high-temperature pulverized coal combustion flame; the high-temperature pulverized coal combustion flame passes
  • the outlet enters the furnace of the boiler to provide a good ignition base and conditions for the subsequent combustion of the pulverized coal in the furnace to meet the needs of stable combustion of the coal powder in the boiler furnace.
  • the pulverized coal burner provided by the invention, it is possible to achieve pulverized coal ignition without adding fuel-assisted combustion during the start-up phase of the boiler, thereby overcoming the defects of unstable combustion of pulverized coal in the prior art.
  • the pulverized coal is ignited by the heat source in the pulverized coal burner, the pulverized coal gas flow enters the furnace in the form of a high-temperature pulverized coal combustion flame, and the pulverized coal no longer depends on the high-temperature flue gas in the furnace. Therefore, when the temperature in the furnace is low, the continuous operation of the boiler can be maintained, and the boiler can be operated at a lower load, the minimum operating load of the boiler can be reduced, and the adaptability of the boiler can be improved.
  • the internal combustion chamber has a main combustion chamber, it can provide a large space for the combustion of pulverized coal, prolong the burning time of the pulverized coal, and the flame formed by the combustion of the pulverized coal can be diffused in the main combustion chamber, thereby improving the entry into the boiler.
  • the high temperature pulverized coal in the furnace burns the stiffness of the flame, thereby improving the stability of the pulverized coal combustion in the boiler.
  • the pulverized coal gas flow in the internal combustion chamber has a predetermined and small excess air ratio, an environment for suppressing the formation of nitrogen oxides can be formed in the internal combustion chamber, and the amount of nitrogen oxides generated during the operation of the boiler is reduced.
  • the heat source ignites the pulverized coal, and a high-reducing atmosphere with high temperature and anoxicity is formed in the internal combustion chamber. Under such a strong reducing atmosphere, the carbon in the pulverized coal cannot react with enough air, so it can only be in the shape of a long cylinder having a predetermined length.
  • the combustion chamber undergoes incomplete, reductive combustion.
  • the pulverized coal is burned in the internal combustion chamber of the pulverized coal burner, the formed high-temperature pulverized coal combustion flame is injected into the boiler furnace to continue combustion, and the entire burn-out process is completed.
  • the nitrogen content in the unburned pulverized coal can be reduced, and the amount of fuel-type nitrogen oxides generated during the combustion of the furnace is reduced. Since the fuel-type nitrogen oxide is a main component of the pulverized coal combustion oxynitride, the furnace can be reduced. The amount of nitrogen oxides produced during combustion.
  • the pulverized coal is separated from the pulverized coal. , reducing the deposition and slagging of pulverized coal, maintaining the conveying performance of the pulverized coal burner, thereby ensuring the stability of the boiler operation; on the other hand, the high-temperature pulverized coal combustion flame enters the furnace of the boiler through the outlet, and the high-temperature pulverized coal combustion flame contains A large amount of flammable gas has strong rigidity, which is beneficial to the optimization of combustion organization in the boiler and improves the efficiency of boiler operation.
  • the technical prejudice of stopping the operation of the heat source when the boiler is normally burned is overcome, and the heat source is set to be sustainable, thereby ensuring continuous igniting of the coal powder, and improving the combustion stability of the pulverized coal.
  • the heat source is set to be sustainable, thereby ensuring continuous igniting of the coal powder, and improving the combustion stability of the pulverized coal.
  • it can ensure that as much pulverized coal as possible can undergo reductive combustion in the anoxic environment that inhibits the formation of fuel-type nitrogen oxides, so that a large amount of nitrogen in the pulverized coal is converted to nitrogen, and finally the fuel is suppressed.
  • the purpose of the formation of nitrogen oxides is provided.
  • the internal combustion chamber further includes a deceleration inlet section that is in contact with the front end of the main combustion chamber; the cross-sectional area of the deceleration inlet section is smaller than the cross-sectional area of the main combustion chamber.
  • the coal powder In order to absorb more heat from the heat released from the heat source and the pulverized coal powder; in this case, the coal powder is more likely to catch fire and burn, thereby improving the stability of combustion of the coal powder in the boiler furnace;
  • the flow rate is correspondingly reduced, so that the pulverized coal stays in the internal combustion chamber having a predetermined length for a longer period of time, so that the nitrogen element in the pulverized coal As soon as possible, it is converted into a reducing intermediate as much as possible, and finally converted into nitrogen gas, thereby further suppressing the formation of fuel-type nitrogen oxides.
  • the cross-sectional area of the deceleration inlet section is gradually increased; the structure can enhance the turbulence intensity of the pulverized coal gas flow while reducing the primary air velocity, thereby improving the concentration of the pulverized coal near the axis of the internal combustion chamber, thereby improving The ignition performance of inferior coal, improving the adaptability of the pulverized coal burner, can also improve the burnout rate of coal powder in the boiler.
  • an acceleration outlet section is disposed after the main combustion chamber, and a cross-sectional area of the acceleration outlet section is smaller than a cross-sectional area of the main combustion chamber to increase the speed of the high-temperature pulverized coal combustion flame entering the furnace furnace to satisfy the furnace.
  • the cross-sectional area of the accelerated outlet section is gradually reduced; the structure can effectively reduce the generation of eddy currents in the pulverized coal gas flow, form an appropriate flow layer on the side wall of the internal combustion chamber, and prevent local burning of the pulverized coal burner outlet. Damage and slagging; can also improve the rigidity of the high-temperature pulverized coal combustion flame, so that the speed and momentum of the high-temperature pulverized coal combustion flame reach the predetermined requirements, and promote the organization of the aerodynamic field in the furnace and the stable combustion of the pulverized coal in the furnace.
  • the internal combustion chamber is formed of a ceramic refractory material by a ceramic refractory material; since the ceramic has good fire resistance and thermal shock resistance, the ceramic refractory layer can maintain a high temperature under continuous high temperature conditions.
  • the mechanical strength is adapted to the sudden change of the temperature field of the internal combustion chamber during the start and stop of the boiler. Therefore, the structure can prolong the service life of the pulverized coal burner; since the ceramic has corrosion resistance, the ceramic refractory layer can Effectively reduce the high temperature corrosion caused by high temperature flue gas on the inner wall of the internal combustion chamber.
  • the structure can keep the outer surface of the pulverized coal burner at a lower temperature, thereby ensuring the safety of the pulverized coal burner and keeping the internal combustion chamber high.
  • the temperature is favorable for the analysis of volatilization in coal powder, and further creates favorable conditions for the stable combustion of coal powder.
  • the heat source is located substantially at the central axis of the cross section of the internal combustion chamber; thus, a uniform combustion flame can be formed on the cross section of the internal combustion chamber, thereby ensuring uniformity of combustion of the pulverized coal and uniformity of the temperature field in the internal combustion chamber.
  • the pulverized coal is firstly burned in the internal combustion chamber of the pulverized coal burner, thereby preheating the pulverized coal burning time and prolonging the pulverized coal in the boiler.
  • FIG. 1 is a schematic structural view of a pre-combustion chamber pulverized coal burner in the prior art
  • FIG. 2 is a schematic diagram of the principle of the overall air classification low NOx combustion technology of the furnace;
  • FIG. 3 is a schematic structural view of the pulverized coal burner provided in the first embodiment;
  • Figure 4 is a schematic structural view of a pulverized coal burner provided in the second embodiment
  • Figure 5 is a schematic view showing the structure of a pulverized coal burner of another structure of the second embodiment
  • Figure 6 is a schematic view showing the structure of the pulverized coal burner provided in the third embodiment
  • Fig. 7 is a schematic view showing the flame propagation of the internal combustion chamber in the third embodiment.
  • the section referred to in this document refers to the section perpendicular to the direction of flow of pulverized coal; and the direction of the flow of pulverized coal is referenced, the position near the inlet of the internal combustion chamber is the front, and the position away from the inlet of the internal combustion chamber is the rear.
  • Embodiment 1 is a diagrammatic representation of Embodiment 1:
  • FIG. 3 is a schematic structural view of a pulverized coal burner provided in the first embodiment.
  • the pulverized coal burner comprises a fire source 200 and an internal combustion chamber 100.
  • the internal combustion chamber 100 has an inlet 101 and an outlet 102, and a long cylindrical main combustion chamber is formed therein; the main combustion chamber forms a suitable space to maintain the internal pulverized coal gas flow. Has a predetermined excess air ratio.
  • the internal combustion chamber 100 further includes a transition duct 300 that communicates with the front end of the main combustion chamber.
  • the fire source 200 extends from the transition duct 300 into the internal combustion chamber 100.
  • the transition duct 300 communicates with the primary air pulverized coal pipeline.
  • the internal combustion chamber 100 has a predetermined length and a cross-sectional area in a flow direction of the pulverized coal gas flow. And can maintain the excess air coefficient in the pulverized coal gas flow is much less than 1.
  • the excess air ratio herein refers to the ratio of the amount of air actually supplied to the internal combustion chamber 100 when burning 1 kg of pulverized coal to the theoretical amount of air required to completely burn 1 kg of pulverized coal.
  • the method of maintaining the predetermined excess air ratio may be to limit the ratio of air to pulverized coal in the pulverized coal gas stream and maintain a high primary pulverized coal concentration.
  • the excess air ratio is related to the coal type: Generally, the larger the moisture of the coal, the smaller the excess air coefficient, and the larger the ash content of the coal, the smaller the excess air coefficient; conversely, the smaller the moisture of the coal, the larger the excess air coefficient.
  • the excess air ratio is preferably between 0.15 and 0.45, within which the pulverized coal burner can maintain stable combustion, and at the same time, a strong reducing atmosphere can be formed in the internal combustion chamber 100 in which the pulverized coal ignites, thereby effectively suppressing the nitrogen oxides. Generation.
  • the fire source 200 is continuously held in the internal combustion chamber, and the pulverized coal entering the internal combustion chamber 100 through the inlet 101 is continuously ignited.
  • the working process of the pulverized coal burner provided in this example is: when the pulverized coal gas having an excess air coefficient of 0.15-0.45 passes through the internal combustion chamber 100, the fire source 200 continuously ignites the pulverized coal in the pulverized coal gas flow, and the pulverized coal is ignited in the internal combustion chamber 100.
  • Internal combustion undergoes incomplete, reductive combustion.
  • the flame formed by reductive combustion propagates in the long cylindrical main combustion chamber and releases heat.
  • a suitable high temperature environment is formed.
  • the powder gas stream forms a high temperature pulverized coal combustion flame that is ejected from the outlet 102.
  • the condition that the continuous source of ignition 200 and the excess air ratio are much less than one maintains a reducing atmosphere within the internal combustion chamber 100.
  • the reducing intermediate reacts with the formed nitrogen oxides to form nitrogen.
  • This example provides the benefit of a pulverized coal burner with stable pulverized coal combustion and reduced boiler nitrogen oxides.
  • the benefits of stabilizing pulverized coal combustion are as follows:
  • the pulverized coal gas is burned in the internal combustion chamber 100, and the formed high-temperature pulverized coal combustion flame is sprayed into the furnace through the outlet 102, so that the pulverized coal does not depend on the high-temperature flue gas in the furnace. Therefore, it provides a good ignition base and conditions for the subsequent combustion of the coal powder in the furnace, and meets the requirement of stable combustion of the coal powder in the boiler furnace.
  • the combustion chamber 100 has a main combustion chamber, which can provide a large space for the combustion of pulverized coal, prolong the burning time of the pulverized coal, and enable the flame formed by the combustion of the pulverized coal to diffuse in the main combustion chamber, thereby improving the high temperature coal entering the furnace furnace.
  • the stiffness of the powder burns the flame, which in turn improves the stability of the pulverized coal combustion in the boiler.
  • the pulverized coal gas flow enters the furnace with high-temperature pulverized coal combustion flame
  • the pulverized coal does not depend on the high-temperature flue gas in the furnace, and the following technical effects are also produced:
  • the fire source 200 can maintain the continuity of the pulverized coal Combustion, the resulting continuous high-temperature pulverized coal combustion flame enters the furnace through the outlet 102. Even if the temperature inside the furnace is low, the high-temperature pulverized coal combustion flame can keep the boiler running continuously, so that the boiler operates at a relatively low load. Improve the adaptability of the boiler.
  • the high-temperature pulverized coal combustion flame contains a large amount of combustible gas and has a strong rigidity, it is advantageous for optimizing the combustion structure in the boiler furnace and improving the efficiency of the boiler operation.
  • the pre-chamber burner improves the ignition heating through the recirculation zone, since the pulverized coal does not need to be ignited by the high-temperature flue gas in the recirculation zone, the separation of the pulverized coal and the gas flow can be reduced, and the reduction can be reduced.
  • the deposition and slagging of pulverized coal keeps the conveying performance of the pulverized coal burner and ensures the stability of the boiler operation.
  • the corresponding nitrogen element is converted into nitrogen gas, thereby reducing the nitrogen content in the pulverized coal entering the furnace and reducing the fuel-type nitrogen oxidation generated when the pulverized coal is burned in the furnace.
  • the amount of material produced since the fuel-type nitrogen oxides are the main components of the nitrogen oxides of the pulverized coal combustion, the amount of nitrogen oxides generated during the combustion of the furnace can be reduced, and the amount of nitrogen oxides generated during the operation of the boiler can be reduced.
  • the aspect ratio of the main combustion chamber may be increased, or the distance through which the pulverized coal gas stream is passed may be increased.
  • the second embodiment of the present invention provides another structure of coal. Powder burner.
  • Embodiment 2 Please refer to FIG. 4 , which is a schematic structural view of a pulverized coal burner provided in the second embodiment.
  • the internal combustion chamber 100 includes a main combustion chamber 120 and a deceleration inlet section 110 that is in contact with the front end of the main combustion chamber 120.
  • the inlet 101 is located at the intersection of the deceleration inlet section 110 and the transition duct 300.
  • the cross-sectional area of the retarding inlet section 110 is smaller than the cross-sectional area of the main combustion chamber 120.
  • the flow velocity of the pulverized coal gas flow is correspondingly reduced.
  • the pulverized coal gas flow having a low flow rate needs to reach the outlet 102 for a longer period of time, thereby prolonging the residence time of the pulverized coal in the internal combustion chamber 100, thereby achieving the purpose of prolonging the internal combustion time.
  • the pulverized coal When the pulverized coal is subjected to incomplete and reductive combustion, the pulverized coal stays in the internal combustion chamber 100 for a longer period of time, and can convert as much nitrogen element as possible into nitrogen gas in the pulverized coal, thereby strengthening the suppression of the fuel-type nitrogen oxides.
  • the pulverized coal can absorb more heat from the heat released by the heat source and the pulverized coal powder, and is more likely to catch fire and burn, and increase the high temperature pulverized coal.
  • the strength of the burning flame in turn, on the one hand, it can strengthen the full combustion of the pulverized coal in the furnace; on the other hand, because the high-temperature pulverized coal combustion flame has high strength, the furnace combustion can be maintained continuously at a lower furnace temperature. Therefore, the minimum operating load of the boiler can be further reduced.
  • the fire source 200 is not limited to continuously igniting the pulverized coal.
  • the fire source 200 may also be an intermittent fire source 200, that is, a spark is ignited at a predetermined time to keep the pulverized coal in the internal combustion chamber 100 from burning;
  • the technical solution is that the fire source 200 is a continuous fire source.
  • the fire source 200 continuously ignites the coal powder to maintain the continuous reduction combustion of the coal powder, overcoming the prior art, only in the boiler The technical bias of igniting pulverized coal with a fire source during the start-up phase.
  • the condition required for igniting the pulverized coal is to make the pulverized coal gas flow reach its ignition point; therefore, the igniting of the pulverized coal is not limited to the fire source 200, nor is it limited to igniting the pulverized coal by means of generating a spark, or may be a heat source capable of generating sufficient heat. As long as the heat generated by the heat source is sufficient to reach the ignition point of the pulverized coal, the purpose of igniting the pulverized coal can also be achieved.
  • the heat source may be a plasma generator disclosed in Chinese Patent Publication No. CN201134973, a gasification high-efficiency energy-saving igniter disclosed in CN1815084, and the like, but is not limited to two heat sources of j3 ⁇ 4.
  • the deceleration inlet section 110 can also be configured as a structure having a gradual cross-sectional area. As shown in Fig. 5, the figure shows a schematic structural view of a pulverized coal burner of another structure of the second embodiment.
  • the pulverized coal burner includes a deceleration inlet section 110 that is in contact with a front end of the main combustion chamber 120.
  • the longitudinal section of the deceleration inlet section 110 has a tapered structure.
  • the cross-sectional area of the deceleration inlet section 110 in the direction of flow of the pulverized coal gas stream Gradually increasing, in this way, the flow velocity of the pulverized coal gas flow gradually decreases during the flow of the pulverized coal gas flow; it can be understood that the longitudinal profile of the deceleration inlet section 110 is not limited to a tapered structure, and may be other structures with a gradual cross-sectional area.
  • Embodiment 3 is a diagrammatic representation of Embodiment 3
  • the pulverized coal gas stream ignited in the internal combustion chamber 100 is taken out through the outlet 102 and introduced into the boiler furnace.
  • An accelerating outlet section is provided in the internal combustion chamber 100.
  • FIG. 6 the figure shows a schematic structural view of a pulverized coal burner provided in the third embodiment.
  • the pulverized coal burner further has an acceleration outlet section 130 that is in contact with the rear end of the main combustion chamber 120. Similarly, in order to ensure The stability of the pulverized coal gas flow rate is changed.
  • the cross-sectional area of the accelerated outlet section 130 is gradually decreased, so that the flow rate of the pulverized coal gas flow is gradually increased, thereby improving the pulverized coal combustion in the boiler.
  • Stability The structure can enhance the turbulence intensity of the pulverized coal gas flow while reducing the primary air velocity, and is beneficial to increase the concentration of the pulverized coal near the inner axis of the internal combustion chamber 100, thereby improving the ignition performance of the inferior coal and improving the adaptability of the pulverized coal burner. It can also improve the burnout rate of pulverized coal in the boiler. It is of course also possible to make the accelerating outlet section 130 a structure having a right-angled cross section, as long as the cross-sectional area is smaller than the cross-sectional area of the main combustion chamber 120, so that the primary air flow rate can be increased.
  • Figure 7 is a schematic illustration of flame propagation of an internal combustion chamber in the third embodiment.
  • the internal combustion chamber 100 has a circular cross section, and the fire source 200 is located on the center line of the internal combustion chamber 100.
  • the fire source 200 from the fire source 200, the high temperature pulverized coal combustion flame propagates toward the outlet 102, and The outlet 102 is sprayed into the furnace.
  • the high-temperature pulverized coal combustion flame has a suitable flow velocity, it can ensure that as much pulverized coal as possible participates in incomplete, reductive combustion; at the same time, since the fire source 200 is basically located at the center line of the internal combustion chamber 100, it can be guaranteed Uniformity and internal combustion of pulverized coal combustion
  • the uniformity of the temperature field of the flue gas in the chamber 100 thus, uniform combustion can ensure that as much pulverized coal as possible participates in the reductive combustion, and converts as much nitrogen as possible into nitrogen in the pulverized coal, thereby strengthening the inhibition of fuel-type nitrogen oxidation.
  • the object is produced. At the same time, more pulverized coal is involved in the combustion and combustion, and can avoid or reduce the occurrence of coal slagging.
  • the above object is not limited to the above specific structure, and the cross section of the internal combustion chamber 100 may be other shapes, for example, may be square, polygonal or elliptical, etc.; while maintaining the fire source 200 at the center of the internal combustion chamber 100 , it is possible to convert as much nitrogen as possible into nitrogen.
  • the internal combustion chamber 100 can also be provided with an outlet adjustment section 140, and the front end of the outlet adjustment section 140 is connected with the rear end of the acceleration outlet section 130 to further adjust the pulverized coal gas flow to meet the boiler.
  • the outlet adjustment section 140 can be a cylindrical structure with a front end and a back end of the same cross-sectional area, or can be set to other specific structures according to actual needs.
  • the pulverized coal gas flow will have a corresponding impact on the fire source 200, and the impact will affect the combustion of the fire source 200 itself; further, the fire source 200 affected by the impact will affect Its ignition performance reduces the reliability of ignition.
  • the strength of the fire source 200 can be enhanced, thereby reducing the influence of the impact of the pulverized coal gas flow on the ignition performance of the fire source 200.
  • a ceramic refractory layer may be disposed in the internal combustion chamber 100.
  • the ceramic refractory layer can maintain high mechanical strength under continuous high temperature conditions to adapt to the boiler start and stop.
  • the temperature field of the internal combustion chamber 100 changes abruptly. Therefore, the structure can prolong the service life of the pulverized coal burner; since the ceramic has corrosion resistance, the ceramic refractory layer can effectively reduce the high temperature flue gas to the inner combustion chamber wall surface.
  • the high temperature is beneficial to the analysis of volatilization in coal powder, and further creates favorable conditions for stable combustion of coal powder. .
  • a boiler is provided, and the boiler package is provided.
  • the furnace there is also the above-mentioned pulverized coal burner, wherein the outlet of the internal combustion chamber of the pulverized coal burner communicates with the furnace of the boiler, so that the burned coal powder enters the furnace to continue combustion.
  • the normal combustion stage of the boiler the energy source of the pulverized coal ignition source, the high temperature flue gas in the furnace, which leads to poor combustion stability of the pulverized coal in the boiler.
  • the coal powder before the coal powder enters the furnace, the coal powder is ignited by the heat source of the pulverized coal burner itself, so that the coal powder is burned in the internal combustion chamber of the pulverized coal burner, and after the fire, the high temperature coal powder is used to burn the flame.
  • the form enters the furnace, and the technical solution fundamentally overcomes the deficiencies in the prior art and improves the stability of pulverized coal combustion in the boiler.
  • the traditional low-NOx combustion technology controls the amount of fuel-type nitrogen oxides produced by creating a reducing reaction zone in the furnace, and by controlling the timing and amount of supplemental combustion air.
  • the present invention provides a boiler provided with the above-mentioned pulverized coal burner, and the pulverized coal is first incompletely and reductively burned in the internal combustion chamber of the pulverized coal burner to make an appropriate amount of pulverized coal.
  • the nitrogen element is converted into nitrogen; then, the pulverized coal is re-entered into the boiler furnace to continue combustion; since the pulverized coal is converted to nitrogen in the refractory combustion process, it can be supplied by air.
  • An oxidizing atmosphere is formed in the boiler furnace to fully react the pulverized coal with the air; thus, the combustion efficiency of the boiler can be improved while reducing the amount of fuel-type nitrogen oxides produced.

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Description

一种煤粉燃烧器及具有该煤粉燃烧器的锅炉 本申请要求于 2009 年 09 月 27 日提交中国专利局、 申请号为 200910175071.4、 发明名称为"一种煤粉燃烧器及具有该煤粉燃烧器的锅 炉"的中国专利申请的优先权， 其全部内容通过引用结合在本申请中。 技术领域
本发明涉及一种煤粉燃烧技术， 尤其涉及一种煤粉燃烧器， 还涉及一 种具有该煤粉燃烧器的锅炉。 背景技术
当前， 锅炉的燃烧过程包括两个阶段： 第一个阶段是锅炉点火阶段， 第二阶段正常燃烧阶段。
在第一个阶段， 锅炉点火时,为了将煤粉点燃， 并保持煤粉的燃烧， 提 高炉膛的温度， 往往需要投入燃油进行助燃， 以将煤粉点燃， 提高炉膛内 温度； 在炉膛内的温度升高到一定高度之后， 进入锅炉燃烧的第二个阶段， 即正常燃烧阶段。
在正常燃烧阶段， 停止投入燃油， 煤粉进入炉膛之后， 在炉膛内的高 温烟气辐射热、 对流热作用下着火， 燃烧， 释放出热量。
当前的锅炉燃烧技术虽然能够保持煤粉的燃烧， 但却存在以下两个主 要不足：
第一个不足就是： 在正常燃烧阶段， 为了保持煤粉的连续燃烧， 需要 保持炉膛内较高的温度； 只有保持炉膛内较高的温度， 煤粉才能依赖炉膛 内高温烟气的辐射热和对流热燃烧， 保持煤粉的燃尽率。 因此， 在锅炉开 始运行初期， 由于炉膛内温度较低， 煤粉的燃尽率非常低， 这就使得锅炉 运行的效率偏低。 而且， 在炉膛内温度低于一个确定的点时， 锅炉就无法 自行保持持续性运行， 存在锅炉中煤粉燃烧稳定性较差的缺陷。 因此， 在 锅炉低负荷运行时， 往往还需要投入燃油助燃， 以保持锅炉的持续运行。
由此可见， 现有技术中， 煤粉燃烧器实际上只是一个燃料传输部件， 并不能保持煤粉燃烧的稳定性。 为了提高锅炉运行过程中， 煤粉燃烧的稳 定性， 当前人们主要从降低煤粉的着火热和提高着火供热两方面入手， 釆 取了相应了措施， 以提高锅炉煤粉燃烧的稳定性。
降低煤粉的着火热主要通过改善一次风的性能实现的， 其方式主要包 括： 提高一次风粉的煤粉质量和浓度； 提高一次风煤粉的初温， 来增加一 次风中煤粉的着火性能； 在该技术方面， 比较有代表性的是 WR燃烧器、 PAX型燃烧器。
提高着火供热的技术措施主要包括： 改变煤粉燃烧器一次风流动的组 织或方向， 强化着火供热， 改善煤粉的着火性能； 提高一次风煤粉气流与 炉膛内高温烟气的接触面积和热质交换强 以下以一个具体实例说明一 种提高着火供热方式的技术方案。
该实例中， 锅炉包括一个预燃室煤粉燃烧器和锅炉本体， 锅炉本体形 成炉膛。 请参考图 1 , 该图为现有技术中， 预燃室煤粉燃烧器的结构示意 图。 该煤粉燃烧器包括一次风管 1、 轴向旋流叶片 2、 预燃室 3、 预燃室出 口 4, 预燃室出口 4与锅炉的炉膛（图中未示出 )相通。 上述结构的煤粉 燃烧器的工作原理是： 煤粉气流通过一次风管 1、 经过轴向旋流叶片 2形 成的一次风旋转气流， 送入圓筒形预燃室 3 , 在一次风进口处的圓锥形端 盖的作用下， 把受限的一次风旋转气流引向周向壁面， 并在预燃室 3中央 形成一个艮大的回流区， 该回流区具有相应的负压。 在预燃室 3内回流区 的负压作用下， 预燃室 3夕卜、 炉膛中的高温烟气通过预燃室出口 4回流到 一次风根部， 并将进入预燃室 3的煤粉点燃， 实现锅炉的预燃， 点燃后的 煤粉再进入炉膛内燃烧。
上述技术措施虽然能够通过改善着火供热的方式提高锅炉中煤粉燃烧 的稳定性， 降低锅炉不投油时的最低运行负荷； 但在锅炉启动阶段， 煤粉 仍然依赖于燃油才能着火、 燃烧， 其负荷适应性及运行的稳定性仍然存在 问题， 存在的技术缺陷仍然没有从根本上加以解决。
另夕卜， 在申请人研发过程中， 还查阅到中国专利文献 CN2580304Y公 开的一种生产成本低、 燃烧完全、 直喷式的碳粉燃烧机， 该碳粉燃烧机设 置于沥青拌合槽、 石料干燥炉或焚化炉等需作大量干燥或焚化的机具或设 备前方， 能够喷出火焰， 以实现对其他物品的焚烧或加热。 为了避免燃烧 液态燃料造成的成本高、 燃烧不完全的不足， 该碳粉燃烧机以碳粉作为燃 料。 该碳粉燃烧机包括本体、 点火器和网状的火种***； 本体内形成强 制引燃内燃室， 强制引燃内燃室末段具有进气孔， 以使空气进入强制引燃 内燃室中； 点火器包括电击棒、 外环管和燃气管， 碳粉通过外环管进入强 制引燃内燃室中， 燃气通过燃气管进入强制引燃内燃室中， 电击棒用于点 燃燃气； 火种***位于靠近强制引燃内燃室的出口位置。 该碳粉燃烧机 的工作过程包括两个阶段， 第一个阶段是点火启动阶段， 在该阶段， 电击 棒点燃燃气， 燃气再将碳粉点燃， 在强制引燃内燃室燃烧； 点燃后的碳粉 通过火种***向外喷出， 同时， 部分碳粉附着在火种***上， 形成碳 粉火种； 在附着在火种***上的碳粉火种达到一定量时， 进入正常运行 阶段。 在正常运行阶段， 通过外环管进入强制引燃内燃室的碳粉由附着在 火种***上的碳粉火种点燃， 并在外燃室进行完全、 充分地燃烧， 进而 提供足够的热量， 保证喷出火焰的强度， 实现对其他物品的焚化。 该技术 方案通过火种***获得足够的火种， 以提供足够的供热， 使碳粉保证持 续燃烧； 由于碳粉在强制引燃内燃室进行完全燃烧， 碳粉的热量在强制引 燃内燃室释放， 因此， 无法在锅炉上应用。
第二个不足是： 在现有技术中， 为了提高煤粉的燃烧效率， 炉膛中需 要保持较高的温度和较高的氧气浓度。 在这种情况下， 煤粉中的氮元素很 容易与氧反应生成氮氧化物， 因此使锅炉的氮氧化物生成量较大， 降低了 锅炉的环保性能。
煤是复杂的高分子碳氢化合物， 其主要成分为： 碳、 氢、 氧、 氮、 硫、 灰分和水分， 其中氮元素含量约为 0.5%-2.5%。 煤中的氮元素在燃烧过程 中的化学变化十分复杂， 燃烧前期主要转化成 NHi ( i=0, 1 , 2 ) 、 HCN 等还原性中间产物和氮氧化物； 燃烧后期， 部分还原性中间产物会与已产 生的氮氧化物反应生成 N2, 其余的中间产物继续与氧反应生成更多的燃料 型氮氧化物； 在煤粉燃烧过程中， 由于煤中的氮元素在高温火焰中发生热 分解生成燃料型氮氧化物， 燃料型氮氧化物约占全部煤粉燃烧过程中氮氧 化物生成量的 75%-90%。 且研究发现： 燃料型氮氧化物的生成量主要与氧 的浓度有关， 在很大的范围内几乎与温度无关。 燃烧过程中， 氧气补充越 及时， 氧量越充足， 煤中氮元素转化成氮氧化物的比例就越大； 相反， 在 缺氧条件下， 更容易产生还原性中间产物， 且最终产生的燃料型氮氧化物 的量也相对较少。
为了减少锅炉的氮氧化物排放量， 当前釆用的方法主要有两种： 一是 在煤粉燃烧产生氮氧化物之后，在这些氮氧化物随烟气排出锅炉尾部烟道， 进入烟自之前， 依靠专门的氮氧化物吸收设备对氮氧化物进行吸收和还 原， 使其转化为其他物质， 中国专利文献 CN1439450就公开了一种与此相 似的技术方案； 二是低氮氧化物燃烧技术， 即减小煤中的氮元素与空气中 的氧反应的可能， 从而抑制燃烧过程中氮氧化物的产生， 中国专利文献 CN101050853就公开了其中的一种技术方案。
传统的低氮氧化物燃烧技术在适当降低炉膛温度， 以控制热力型氮氧 化物生成的同时， 在炉膛内营造范围尽量大的含氧量较低的还原性反应区 来控制燃料型氮氧化物的生成量， 其主要实现方式是： 1 )炉膛整体空气分 级。 如图 2所示炉膛整体空气分级低氮氧化物燃烧技术的原理示意图， 在 炉膛下部， 形成还原性燃烧区域 A, 在炉膛上部形成富氧燃烧区域 B, 在 还原性燃烧区域 A中， 尽量减少空气的供入量， 以使煤粉进行不完全的、 还原性燃烧； 在炉膛的上部的富氧燃烧区 B, 以燃尽风等形式进行补氧， 为煤粉完全燃烧提供充足的氧气， 以在保证炉膛整体的供氧量的同时， 保 证煤粉的燃尽率， 保证锅炉的运行效率。 2 )现有技术中还提供了一种浓淡 分级降低氮氧化物的技术方案在该技术方案中， 对煤粉气流进行浓淡分 离， 将锅炉炉膛分为两个区域， 将 85%左右的煤粉送入氧含量较高的第一 区域进行富氧燃烧， 生成大量的氮氧化物； 将 15%左右的煤粉送入氧含量 较低的第二区域， 进行还原性燃烧； 并将第一区域生成的氮氧化物送入第 二区域中， 通过还原性燃烧将第一区域生成的氮氧化物还原， 抑制氮氧化 物的生成， 降低锅炉的氮氧化物的排放量。
在传统的低氮氧化物燃烧技术中， 在炉膛内营造还原燃烧区的方式就 是调整煤粉气流的风粉比例， 即通过减小预定区域的过量空气系数的方式 在预定区域形成还原性反应区。 然而， 减小过量空气系数会导致对锅炉的 性能产生不利影响， 会使煤粉的燃尽率降低， 使锅炉飞灰的含碳量增加， 降低锅炉的燃烧效率， 还可能会影响煤粉燃烧的稳定性。 为了避免减小过 量空气系数对锅炉产生的上述不利影响， 需要向锅炉内补入空气， 以满足 煤粉燃尽的要求。 空气的补入时机和补充量成为锅炉中煤粉燃烧性能的关 键， 空气补入不能太晚， 补入量也不能太少， 这一方面限制了还原性反应 区域的大小和还原性燃烧的程度， 进而削弱了抑制氮氧化物生成的作用； 另一方面， 为制造还原性燃烧区域， 强制性地破坏了煤粉的燃烧气氛， 不 总之， 现有低氮氧化物燃烧技术的作用范围仅限于锅炉炉膛内， 抑制 氮氧化物生成的作用有限， 同时还会降低锅炉的燃烧效率。 而在锅炉产生 的氮氧化物中， 燃料型氮氧化物所占比重很大。 因此， 如何在保证锅炉的 运行效率的情况下， 降低燃料型氮氧化物的生成量是当前亟待解决的技术 问题。 发明内容
针对上述现有技术不足， 本发明的第一个目的在于提供一种能够提高 锅炉煤粉燃烧稳定性的煤粉燃烧器， 同时能够降低锅炉运行过程中氮氧化 物生成量。
本发明的第二个目的在于提供一种包括上述煤粉燃烧器的锅炉。
为了实现上述第一个目的， 本发明提供的煤粉燃烧器包括热源和维持 内部煤粉气流具有预定的过量空气系数的内燃室，所述热源位于内燃室内， 所述内燃室具有进口， 长筒形主燃烧室和出口； 所述热源能够点燃通过内 燃室的煤粉， 并使煤粉在内燃室内进行还原性燃烧。
优选的， 所述热源为持续性热源， 以持续性地点燃煤粉。
优选的， 所述内燃室包括与所述主燃烧室前端相接的减速进口段， 所 述减速进口段的截面积小于主燃烧室的截面积。
优选的，在煤粉气流流动方向上，所述减速进口段的截面积逐渐增加。 优选的， 所述内燃室还包括与所述主燃烧室后端相接的加速出口段； 所述加速出口段的截面积小于主燃烧室的截面积。
优选的，在煤粉气流流动方向上，所述加速出口段的截面积逐渐减小。 优选的， 所述内燃室还包括与加速出口段后端相接的出口调整段。 优选的， 所述出口调整段前端和后端的截面积相等。 优选的， 所述内燃室内壁具有陶瓷质耐火材料层。
为了实现上述第二个目的，本发明还提供的锅炉包括炉体形成的炉膛， 还包括上述任一种煤粉燃烧器； 所述煤粉燃烧器内燃室的出口与所述炉膛 相通， 以便于使燃烧着的煤粉进入炉膛内继续燃烧。
与现有技术中的燃烧燃烧器不同， 本发明提供的煤粉燃烧器不仅仅是 一个燃料输送部件， 还包括内燃室， 所述内燃室用于维持其内部的煤粉气 流具有预定的、 较小的过量空气系数； 所述主燃烧室为长筒形， 具有预定 的长度； 位于内燃室内的所述热源能够点燃通过内燃室的煤粉， 使煤粉在 内燃室内进行还原性燃烧。 由于上述区别， 具有该煤粉燃烧器的锅炉能够 产生下述技术效果：
第一、 在锅炉的启动阶段和正常燃烧阶段， 热源都能够点燃通过内燃 室的煤粉，使通过内燃室的煤粉在内燃室中燃烧，形成高温煤粉燃烧火焰； 高温煤粉燃烧火焰通过出口进入锅炉的炉膛中， 为煤粉在炉膛内的后续燃 烧提供良好的着火基础和条件， 满足锅炉炉膛内煤粉稳定燃烧的需要。 因 此， 用本发明提供的煤粉燃烧器， 在锅炉启动阶段， 不需要加入燃油助燃， 就可以实现煤粉着火，进而能够克服现有技术中，煤粉燃烧不稳定的缺陷。
第二、 由于煤粉在煤粉燃烧器中由热源点燃， 煤粉气流以高温煤粉燃 烧火焰的形式进入炉膛， 煤粉不再依赖于炉膛内的高温烟气着火。 因此， 在炉膛内温度较低时， 也能够保持锅炉的持续运行， 进而能够使锅炉在比 较低的负荷下运行， 降低锅炉的最低运行负荷， 提高锅炉的适应性能。
第三、 由于内燃室中具有主燃烧室， 能够为煤粉的燃烧提供较大空间， 延长煤粉的燃烧时间， 使煤粉燃烧形成的火焰能够在主燃烧室中扩散， 从 而能够提高进入锅炉炉膛中的高温煤粉燃烧火焰的刚度， 进而提高锅炉中 煤粉燃烧的稳定性。
第四、 由于内燃室中维持煤粉气流具有预定的、较小的过量空气系数， 内燃室中能够形成抑制氮氧化物生成的环境， 减少锅炉运行过程中， 氮氧 化物的生成量。 在煤粉气流通过进口进入内燃室后， 热源将煤粉点燃， 内 燃室内形成高温、 缺氧的强还原性气氛。 在这种强还原性气氛下， 煤粉中 的碳无法与足够的空气进行反应， 因此只能在长筒形、 具有预定长度的主 燃烧室进行不完全的、 还原性燃烧。 还原性燃烧的结果是： 生成的碳化物 以一氧化碳为主； 同时， 由于没有足够的氧同煤粉中的氮元素结合， 因此， 煤粉中的氮元素倾向于与氢、 碳等反应， 转化为 NHi ( i=0, 1 , 2 )、 HCN 等还原性中间产物。 这些还原性中间产物与部分已生成的氮氧化物继续反 应， 生成氮气， 最终使较多的氮元素转化成氮气。 煤粉在煤粉燃烧器内燃 室内燃烧后， 形成的高温煤粉燃烧火焰喷入锅炉炉膛中继续燃烧， 完成整 个燃尽过程。 这样就能够减少未燃尽煤粉中的氮元素含量， 减少炉膛燃烧 过程中燃料型氮氧化物的生成量； 由于燃料型氮氧化物为煤粉燃烧氮氧化 物主要组成部分， 从而能够减少炉膛燃烧过程中氮氧化物的生成量。
另外， 与预燃室燃烧器通过回流区提高供火热的技术方案相比， 由于 不需要设置相应的回流区弓 I燃煤粉， 这在一方面可以减少由于回流而造成 的煤粉与气流分离， 减少煤粉的沉积、 结渣， 保持煤粉燃烧器的输送性能， 进而保证锅炉运行的稳定性； 另一方面， 高温煤粉燃烧火焰通过出口进入 锅炉的炉膛中， 高温煤粉燃烧火焰含有大量的可燃气体， 且具有较强的刚 性， 从而有利于锅炉内燃烧组织的优化， 提高锅炉运行的效率。
在进一步的技术方案中， 克服锅炉正常燃烧时， 热源停止工作的技术 偏见， 将所述热源设置为可持续的， 从而能够保证持续不断地将煤粉提前 点燃， 一方面能够提高煤粉燃烧稳定的程度； 另一方面能够保证尽可能多 的煤粉在这种抑制燃料型氮氧化物生成的缺氧环境中进行还原性燃烧， 使 煤粉中的氮元素大量向氮气转化， 最终实现抑制燃料型氮氧化物生成的目 的。
在进一步的技术方案中， 由于内燃室还包括与主燃烧室前端相接的减 速进口段； 所述减速进口段的截面积小于主燃烧室的截面积。 在煤粉气流 从减速进口段进入主燃烧室时， 由于截面积增加， 其流速会相应减小； 进 一步地， 该结构一方面可以使煤粉在具有预定长度的内燃室中停留较长的 时间， 以从热源及已着火的煤粉放出的热量中吸收更多的热量； 在这种情 况下， 煤粉更容易着火、 燃烧， 进而提高煤粉在锅炉炉膛中燃烧的稳定性； 另一方面使煤粉气流从减速进口段进入主燃烧室时， 流速相应减小， 这样 可以使煤粉在具有预定长度的内燃室中停留较长的时间， 使煤粉中的氮元 素尽早、 尽多地转化成还原性中间产物， 最终转化为氮气， 进而更好地抑 制燃料型氮氧化物的生成。
在进一步的技术方案中， 减速进口段的截面积逐渐增加； 该结构能够 在降低一次风速度的同时， 增强煤粉气流的湍流强度， 有利于提高内燃室 内轴线附近煤粉的浓度， 从而能够提高劣质煤的着火性能， 提高煤粉燃烧 器的适应性能， 还能够提高锅炉中煤粉的燃尽率。
在进一步的技术方案中， 在主燃烧室之后设加速出口段， 所述加速出 口段的截面积小于主燃烧室的截面积， 以提高进入锅炉炉膛内的高温煤粉 燃烧火焰的速度， 满足炉膛整体燃烧组织对煤粉燃烧器出口高温煤粉燃烧 火焰速度、 动量提出的要求。
在进一步的技术方案中， 加速出口段的截面积逐渐减小； 该结构能够 有效减少煤粉气流中涡流的产生， 在内燃室边壁形成适当的流动层， 防止 煤粉燃烧器出口的局部烧损和结渣；还能够提高高温煤粉燃烧火焰的刚性， 使高温煤粉燃烧火焰的速度、 动量达到预定要求， 促进炉膛内空气动力场 的组织和炉膛内煤粉的稳定燃烧。
在进一步的技术方案中， 所述内燃室由陶瓷质耐火材料形成陶瓷质耐 火材料层； 由于陶瓷具有良好的耐火性能和耐热震性， 陶瓷质耐火材料层 能够在持续高温条件下保持较高的机械强度， 以适应锅炉启动、 停止过程 中， 内燃室温度场的急剧变化， 因此， 该结构能够延长煤粉燃烧器的使用 寿命； 由于陶瓷具有耐蚀性， 因此， 陶瓷质耐火材料层能够有效减轻高温 烟气对内燃室壁面所造成的高温腐蚀。 由于陶瓷具有保温功能， 具有较小 的传热系数， 该结构能够使煤粉燃烧器的外表面保持较低的温度， 进而保 证煤粉燃烧器的使用安全性， 同时能够使内燃室内保持较高的温度， 有利 于煤粉中挥发分析出 , 进一步地为煤粉的稳定燃烧创造有利条件。
在进一步的技术方案中，使热源基本位于内燃室截面的中心轴线位置； 这样能够在内燃室截面上形成均勾的燃烧火焰， 进而保证煤粉燃烧的均匀 性和内燃室内温度场的均匀性。
本发明提供的具有该煤粉燃烧器的锅炉中， 煤粉首先在煤粉燃烧器的 内燃室内进行燃烧， 从而把煤粉燃烧的时间提前， 延长了煤粉在锅炉内的 燃烧时间； 这不仅为煤粉进入炉膛燃烧提供稳定着火和燃烧的条件， 实现 了锅炉炉膛内煤粉燃烧的稳定性，提高了煤粉的燃尽度和锅炉的运行效率 , 而且， 在内燃室煤粉进行不完全的、 还原性燃烧时， 还能够使煤粉中的氮 元素主要转化为氮气， 降低进入炉膛的未燃尽煤粉中的氮元素含量； 这样 能够减少炉膛燃烧过程中燃料型氮氧化物的生成量， 因此， 本发明提供的 锅炉能够大幅度地降低氮氧化物的排放量。 附图说明
图 1为现有技术中， 预燃室煤粉燃烧器的结构示意图；
图 2是炉膛整体空气分级低氮氧化物燃烧技术的原理示意图； 图 3为实施例一提供的煤粉燃烧器的结构示意图；
图 4为实施例二提供的煤粉燃烧器的结构示意图；
图 5示出了实施例二的另一种结构的煤粉燃烧器的结构示意图； 图 6示出了实施例三提供的煤粉燃烧器的结构示意图；
图 7为实施例三中内燃室的火焰传播的示意图。
具体实施方式
以下结合附图对本发明的具体实施方式进行描述， 本部分描述仅仅是 为了详细说明本发明提供的技术方案， 具体的描述顺序和用语不应当形成 对本发明保护范围的任何限制。
本文件所说的截面是指与煤粉流动方向相垂直的断面； 并以煤粉流动 方向为参照， 靠近内燃室进口位置为前， 远离内燃室进口的位置为后。
实施例一：
请参考图 3 , 该图为实施例一提供的煤粉燃烧器的结构示意图。 该煤 粉燃烧器包括火源 200和内燃室 100,内燃室 100具有进口 101和出口 102, 其内形成长筒状的主燃烧室； 主燃烧室形成一个适合的空间， 以维持内部 煤粉气流具有预定的过量空气系数。 本例中， 内燃室 100还包括与主燃烧 室前端相通的过渡管道 300 , 火源 200从过渡管道 300伸入内燃室 100中； 过渡管道 300与一次风煤粉管道相通。
在煤粉气流流动方向上， 所述内燃室 100具有预定的长度和截面积， 并能够维持煤粉气流中的过量空气系数远小于 1。 这里的过量空气系数即 是指， 燃烧 1kg煤粉时实际供入内燃室 100的空气量与完全燃烧 1kg煤粉 时所需的理论空气量的比值。 维持预定的过量空气系数的方式可以是限制 煤粉气流中空气与煤粉的比例， 保持较高的一次风煤粉浓度。 过量空气系 数与煤种有关： 一般来说， 煤的水分越大， 过量空气系数越小， 煤的灰分 越大， 过量空气系数越小； 反之， 煤的水分越小， 过量空气系数越大， 煤 的灰分越小， 过量空气系数越大； 通过简单的试验， 就可以确定适合的过 量空气系数， 获得最优的技术效果。 过量空气系数优选在 0.15-0.45之间， 在该范围内煤粉燃烧器能够维持稳定燃烧， 同时可以实现在煤粉着火的内 燃室 100内形成强烈的还原性气氛， 从而有效地抑制氮氧化物的生成。
本例中， 为了实现内燃室 100内煤粉燃烧的持续性， 所述火源 200持 续地保持在内燃室中， 并持续性地将通过进口 101进入内燃室 100的煤粉 点燃。
本例提供的煤粉燃烧器的工作过程是： 过量空气系数为 0.15-0.45的煤 粉气流通过内燃室 100时， 火源 200持续地将煤粉气流中煤粉点燃， 煤粉 在内燃室 100内燃烧进行不完全的、 还原性燃烧， 还原性燃烧形成的火焰 在长筒状的主燃烧室中传播， 并释放出热量； 在内燃室 100, 特别在主燃 烧室中形成适当高温环境， 煤粉气流形成高温煤粉燃烧火焰从出口 102喷 出。 还原性燃烧过程中， 持续性火源 200和过量空气系数远小于 1的条件 使内燃室 100内维持一个还原性气氛。 在该高温环境下， 还原性气氛使煤 粉中的氮元素首先被热分解， 并转化成 NHi ( i=0, 1 , 2 )、 HCN等还原性 中间产物和氮氧化物污染物； 然后， 还原性中间产物再与已生成的氮氧化 物反应生成氮气。
本例提供煤粉燃烧器具有稳定煤粉燃烧和降低锅炉氮氧化物生成量的 益处。
稳定煤粉燃烧的益处具体体现是： 煤粉气流在内燃室 100内燃烧， 形 成的高温煤粉燃烧火焰通过出口 102喷到炉膛中， 这样， 煤粉就不依赖于 炉膛内的高温烟气着火， 从而为煤粉后续在炉膛内的继续燃烧提供良好的 着火基础和条件， 满足锅炉炉膛中， 煤粉稳定燃烧的需要。 而且， 由于内 燃室 100中具有主燃烧室， 能够为煤粉的燃烧提供较大空间， 延长煤粉的 燃烧时间 ，使煤粉燃烧形成的火焰能够在主燃烧室中扩散，提高进入锅炉 炉膛中的高温煤粉燃烧火焰的刚度， 进而提高锅炉中煤粉燃烧的稳定性。
进一步的， 由于煤粉气流以高温煤粉燃烧火焰进入炉膛， 煤粉不依赖 于炉膛内的高温烟气着火， 还会产生以下技术效果： 第一， 由于火源 200 能够保持煤粉的持续性燃烧， 产生的持续性的高温煤粉燃烧火焰通过出口 102 进入炉膛中， 即使炉膛内温度较低， 高温煤粉燃烧火焰也能够保持锅 炉的持续运行，进而使锅炉在比较低的负荷下运行，提高锅炉的适应性能。 第二， 由于高温煤粉燃烧火焰含有大量的可燃气体， 且具有较强的刚性， 从而有利于锅炉炉膛中燃烧组织的优化， 提高锅炉运行的效率。 第三， 与 现有技术中的预燃室燃烧器通过回流区提高着火供热的技术方案相比， 由 于煤粉不需要由回流区的高温烟气点燃， 可以减少煤粉与气流分离， 减少 煤粉的沉积、 结渣， 保持煤粉燃烧器的输送性能， 保证锅炉运行的稳定性。
降低锅炉氮氧化物生成量的益处主要体现是：
煤粉在内燃室 100内进行还原性燃烧过程中， 相应的氮元素转化为氮 气， 从而能够减少进入炉膛的煤粉中的氮元素含量， 减少煤粉在炉膛中燃 烧时产生的燃料型氮氧化物的生成量； 由于燃料型氮氧化物为煤粉燃烧的 氮氧化物的主要组成部分， 从而能够减少炉膛燃烧过程中氮氧化物的生成 量， 减少锅炉运行过程中氮氧化物的生成量。 而且， 煤粉在锅炉炉膛中进 行燃烧时， 可以向锅炉炉膛中供入足够的空气， 以使煤粉在炉膛中进行充 分的燃烧， 进而避免了现有技术中， 为了形成还原性燃烧区而导致锅炉运 行效率低的问题， 兼顾锅炉运行效率和锅炉的环保性能。
可以理解， 煤粉在燃烧室 100内的缺氧环境中停留的时间越长， 还原 性燃烧程度越高， 煤粉中的越多的氮元素转化为氮气。 为延长煤粉在内燃 室 100内的停留时间， 可以增加主燃烧室的长径比， 也可以通过增加煤粉 气流通过的距离。 在不改变内燃室 100的截面积和长度的情况下， 还可以 通过改变煤粉气流的流动速度实现； 为了降低煤粉气流的流动速度， 本发 明实施例二就提供了另一种结构的煤粉燃烧器。
实施例二： 请参考图 4 , 该图为实施例二提供的煤粉燃烧器的结构示意图。 在实 施例一的基础上， 所述内燃室 100包括主燃烧室 120和与主燃烧室 120前 端相接的减速进口段 110, 进口 101位于减速进口段 110与过渡管道 300 的交会处。 如图所示， 减速进口段 110的截面积小于主燃烧室 120的截面 积。 在煤粉气流从截面积较小的减速进口段 110进入截面积较大的主燃烧 室 120时， 煤粉气流的流速会相应减小。 这样， 在内燃室 100长度没有改 变的情况下， 流速低的煤粉气流需要更长时间到达出口 102, 从而延长了 煤粉在内燃室 100内的停留时间， 进而实现延长内燃时间的目的。
在煤粉进行不完全的、 还原性燃烧时， 煤粉在内燃室 100内停留的时 间长一些， 能够使煤粉中尽可能多的氮元素转化成氮气， 进而强化抑制燃 料型氮氧化物的技术效果。
使煤粉在具有预定长度的内燃室中停留较长的时间， 还可以使煤粉从 热源及已着火的煤粉放出的热量中吸收更多的热量， 更容易着火、 燃烧， 增加高温煤粉燃烧火焰的强度； 进而， 一方面可以强化煤粉在炉膛中的充 分燃烧； 另一方面， 由于高温煤粉燃烧火焰具有较高的强度， 能够在更低 的炉膛温度下保持炉膛燃烧的持续运行， 从而能够进一步地降低锅炉的最 低运行负荷。
可以理解， 火源 200不限于持续性点燃煤粉， 火源 200也可以为间断 式火源 200 , 即以预定的时间产生火花点燃煤粉， 以使内燃室 100 内的煤 粉保持燃烧； 优选的技术方案是， 火源 200为持续性火源， 在锅炉正常燃 烧阶段， 火源 200持续性点燃煤粉， 以保持煤粉进行持续性的还原性燃烧， 克服现有技术中， 仅在锅炉启动阶段用火源点燃煤粉的技术偏见。 可以理 解， 点燃煤粉需要的条件是使煤粉气流达到其着火点； 因此， 点燃煤粉不 限于火源 200, 也不限于通过产生火花的方式点燃煤粉， 也可以是能够产 生足够热量的热源， 只要热源产生的热量足以达到煤粉的着火点， 同样能 够实现点燃煤粉的目的。 热源可以是中国专利文献 CN201134973 公开的 等离子发生器， CN1815084公开的一种气化高效节能点火器等等， 但不限 于 j¾两种热源。
可以理解， 实施例二提供的煤粉燃烧器中， 虽然能够延长煤粉气流在 内燃室 100内停留的时间， 但在减速进口段 110和主燃烧室 120之间由于 存在直角结构， 该结构容易使煤粉气流受到涡流和死区的影响， 产生积粉 的问题。 为此， 还可以将减速进口段 110设置为截面积渐变的结构。 如图 5 所示， 该图示出了实施例二的另一种结构的煤粉燃烧器的结构示意图。 该煤粉燃烧器包括与主燃烧室 120前端相接的减速进口段 110 , 该减速进 口段 110的纵向剖面为锥形结构， 在煤粉气流流动方向上， 所述减速进口 段 110的截面积逐渐增加， 这样， 在煤粉气流流动过程中， 煤粉气流的流 速逐渐减小； 可以理解，减速进口段 110的纵向剖面也不限于为锥形结构， 也可以是截面积渐变的其他结构。
实施例三：
在内燃室 100内点燃的煤粉气流通过出口 102引出， 并引入到锅炉炉 膛时， 为了使引出的高温煤粉燃烧火焰具有较高的刚性， 并适应锅炉炉膛 整体的燃烧组织需要，还可以在内燃室 100内设加速出口段。如图 6所示， 该图示出了实施例三提供的煤粉燃烧器的结构示意图， 该煤粉燃烧器还具 有与主燃烧室 120后端相接的加速出口段 130; 同样， 为了保证煤粉气流 流速改变时的稳定性， 在煤粉气流流动方向上， 优选的， 加速出口段 130 的截面积逐渐减小， 以使煤粉气流的流速逐渐增加， 进而， 提高锅炉中煤 粉燃烧的稳定性。 该结构能够在降低一次风速度的同时， 增强煤粉气流的 湍流强度， 有利于提高内燃室 100内轴线附近煤粉的浓度， 从而能够提高 劣质煤的着火性能， 提高煤粉燃烧器的适应性能， 还能够提高锅炉中煤粉 的燃尽率。 当然也可以将加速出口段 130做成纵向截面为直角的结构， 只 要是其截面积小于主燃烧室 120的截面积就能够实现增加一次风流速的目 的。
参考图 7 , 图 7为实施例三中内燃室的火焰传播的示意图。 本例中， 内燃室 100的截面为圓形， 火源 200位于内燃室 100的中心线上； 从图 7 可以看出， 从火源 200开始， 高温煤粉燃烧火焰向出口 102传播， 并从出 口 102喷入炉膛中。 只要高温煤粉燃烧火焰具有合适的流动速度， 就能够 保证尽可能多的煤粉参与不完全的、 还原性燃烧； 同时， 由于火源 200基 本位于内燃室 100的中心线上， 因此， 可以保证煤粉燃烧的均匀性和内燃 室 100内烟气温度场的均匀性； 这样， 均匀燃烧就能够保证尽可能多的煤 粉参与还原性燃烧， 使煤粉中尽可能多的氮元素转化为氮气， 从而强化抑 制燃料型氮氧化物产生。 同时， 更多的煤粉参与燃烧和燃烧的均勾性， 还 可以避免或减少煤粉结渣的发生。
可以理解， 实现上述目的不限于上述具体结构， 内燃室 100截面可以 是其他形状， 比如说， 可以是方形， 多边形或椭圓形， 等等形状； 在保持 火源 200在内燃室 100中心处时， 就可以使尽可能多的氮元素转化氮气排 出。 如图 6和图 7所示， 内燃室 100还可以设置出口调整段 140, 并使出 口调整段 140的前端与加速出口段 130后端相接， 以对煤粉气流作进一步 调整， 满足锅炉中燃烧组织的需要， 提高锅炉炉膛煤粉燃烧的稳定性； 出 口调整段 140可以为前端和后端截面积相等的筒形结构， 也可以根据实际 需要设置为其他具体结构。
在煤粉气流通过进口 101进入内燃室 100时， 煤粉气流会对火源 200 产生相应的冲击， 这种冲击会影响火源 200 自身的燃烧； 进一步地， 受到 冲击影响的火源 200会影响其点火性能， 降低点火的可靠性。 为了保证火 源 200点火的可靠性， 可以加强火源 200的强度， 从而减小煤粉气流冲击 对火源 200点火性能的影响。
由于煤粉持续地在内燃室 100内燃烧， 持续的高温可能会使煤粉燃烧 器的使用寿命缩短。 为了提高内燃室 100使用寿命， 还可以在内燃室 100 内设置陶瓷质耐火材料层。 与单纯金属侧壁形成的内燃室 100相比， 由于 陶瓷具有良好的耐火性能和耐热震性， 陶瓷质耐火材料层能够在持续高温 条件下保持较高的机械强度， 以适应锅炉启动、 停止过程中， 内燃室 100 温度场的急剧变化， 因此， 该结构能够延长煤粉燃烧器的使用寿命； 由于 陶瓷具有耐蚀性， 因此， 陶瓷质耐火材料层能够有效减轻高温烟气对内燃 室壁面所造成的高温腐蚀。 由于陶瓷具有保温功能，具有较小的传热系数， 该结构能够使煤粉燃烧器的外表面保持较低的温度， 进而保证煤粉燃烧器 的使用安全性， 同时能够保持内燃室 100内较高的温度， 有利于煤粉中挥 发分析出 , 进一步地为煤粉稳定燃烧创造有利条件。。
在提供上述煤粉燃烧器的基础上， 还提供了一种锅炉， 提供的锅炉包 括炉膛， 还具有上述的煤粉燃烧器， 该煤粉燃烧器的内燃室的出口与锅炉 的炉膛相通， 以便于使燃烧着的煤粉进入炉膛内继续燃烧。
根据背景技术中的描述， 现有技术中， 锅炉正常燃烧阶段， 煤粉着火 的能量来源炉膛内的高温烟气，这一点导致了锅炉中煤粉燃烧稳定性较差。 本发明从另一角度出发， 在煤粉进入炉膛之前， 用煤粉燃烧器本身的热源 点燃煤粉， 使煤粉在煤粉燃烧器的内燃室内燃烧， 在着火后， 以高温煤粉 燃烧火焰的形式进入炉膛中， 该技术方案从根本上克服了现有技术中的不 足， 提高了锅炉中煤粉燃烧的稳定性。
同样， 在降低氮氧化物方面， 传统的低氮氧化物燃烧技术通过在炉膛 中营造还原性反应区来控制燃料型氮氧化物的生成量， 并通过控制助燃空 气的补入时机和补入量来改善锅炉的燃烧性能。 与传统的低氮氧化物燃烧 技术不同， 本发明提供锅炉设置有上述煤粉燃烧器， 煤粉首先在上述煤粉 燃烧器的内燃室中进行不完全的、 还原性燃烧， 使煤粉中适量的氮元素转 化为氮气； 然后， 煤粉再进入锅炉炉膛中继续燃烧； 由于煤粉在还原性燃 烧过程上， 煤粉中的一部分氮元素已经转化为氮气， 因此， 可以通过供入 空气的方式在锅炉炉膛中形成氧化性气氛，使煤粉与空气充分反应；从而， 这样能够在降低燃料型氮氧化物的生成量的同时， 提高锅炉的燃烧效率。
以上所述仅是本发明的优选实施方式， 应当指出， 对于本技术领域的 普通技术人员来说， 在不脱离本发明原理的前提下， 还可以做出若干改进 和润饰， 也可以上述具体实施方式的进行组合， 这些改进、 润饰及组合形 成的技术方案也应视为本发明的保护范围。

Claims

权 利 要 求
1、 一种煤粉燃烧器， 其特征在于， 包括热源和维持内部煤粉气流具有 预定的过量空气系数的内燃室， 所述热源位于内燃室内， 所述内燃室具有 进口， 长筒形主燃烧室和出口； 所述热源能够点燃通过内燃室的煤粉， 并 使煤粉在内燃室内进行还原性燃烧。
2、根据权利要求 1所述的煤粉燃烧器， 其特征在于， 所述热源为持续 性热源， 以持续性地点燃煤粉。
3、根据权利要求 1或 2所述的煤粉燃烧器， 其特征在于， 所述内燃室 包括与所述主燃烧室前端相接的减速进口段， 所述减速进口段的截面积小 于主燃烧室的截面积。
4、根据权利要求 3所述的煤粉燃烧器， 其特征在于， 在煤粉气流流动 方向上， 所述减速进口段的截面积逐渐增加。
5、 根据权利要求 1-4任一项所述的煤粉燃烧器， 其特征在于， 所述内 燃室还包括与所述主燃烧室后端相接的加速出口段； 所述加速出口段的截 面积小于主燃烧室的截面积。
6、根据权利要求 5所述的煤粉燃烧器， 其特征在于， 在煤粉气流流动 方向上， 所述加速出口段的截面积逐渐减小。
7、根据权利要求 5或 6所述的煤粉燃烧器， 其特征在于， 所述内燃室 还包括与加速出口段后端相接的出口调整段。
8、根据权利要求 7所述的煤粉燃烧器， 其特征在于， 所述出口调整段 前端和后端的截面积相等。
9、 根据权利要求 1-8中任一项所述的煤粉燃烧器， 其特征在于， 所述 内燃室内壁具有陶瓷质耐火材料层。
10、 一种锅炉， 包括炉体形成的炉膛， 其特征在于， 还包括权利要求 1至权利要求 9中任一项所述的煤粉燃烧器； 所述煤粉燃烧器内燃室的出 口与所述炉膛相通， 以便于使燃烧着的煤粉进入炉膛内继续燃烧。
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CN101532662A (zh) * 2008-03-14 2009-09-16 烟台龙源电力技术股份有限公司 一种采用内燃式燃烧器的煤粉锅炉降低氮氧化物的方法

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