Ammonia-doped pulverized coal combustion device and control method

Abstract

The invention discloses an ammonia-doped pulverized coal combustion device and a control method, and belongs to the technical field of fuel combustion, the ammonia-doped pulverized coal combustion device comprises a pulverized coal burner, an ammonia gas burner and an ignition burner, and the pulverized coal burner is provided with a pulverized coal combustion runner; the ammonia gas burner is connected with the pulverized coal burner, at least part of the ammonia gas burner is arranged in the pulverized coal burning runner in a penetrating manner, and the ammonia gas burner is provided with an ammonia gas burning runner communicated with the pulverized coal burning runner; the ignition burner comprises a flow guide pipe, an ignition gun and a net sleeve, the flow guide pipe is connected with the ammonia gas burner and provided with a first gas inlet end, a first gas outlet end and a flow guide cavity, the first gas outlet end is arranged in the ammonia gas burning flow channel in a penetrating mode and provided with a plurality of gas outlet holes, and the gas outlet holes communicate with the ammonia gas burning flow channel; the net cover wraps the first gas outlet end and covers the multiple gas outlet holes, the ignition gun penetrates through the flow guide cavity and is provided with an ignition end, the ignition end penetrates out of the first gas outlet end and the net cover, the combustion speed and the ignition range of ammonia gas are increased, and the ignition success rate is ensured.

Description

Technical Field

[0001] This invention relates to the field of fuel combustion technology, and in particular to an ammonia-blended pulverized coal combustion device and control method. Background Technology

[0002] Coal is a crucial primary energy source, and coal-fired power generation plays a vital role in electricity supply. However, traditional coal-fired power generation processes generate significant amounts of carbon dioxide emissions. Therefore, newly built units are generally required to have provisions for low-carbon retrofitting, and units with the necessary conditions are encouraged to implement low-carbon construction. Ammonia, a widely recognized zero-carbon fuel, possesses high energy density and has a well-developed storage and transportation system. Ammonia-blended pulverized coal combustion is considered an effective way to reduce carbon dioxide emissions from coal-fired power plants at the combustion source.

[0003] In related technologies, some burners use ammonia as ignition fuel to simplify the system, but such burners generally suffer from drawbacks such as low ammonia combustion speed, narrow ignition range, or difficulty in maintaining the flame. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an ammonia-blended pulverized coal combustion device, which is beneficial to improving the combustion rate of ammonia and increasing the ignition range, thereby ensuring the ignition success rate.

[0005] The present invention also proposes a control method.

[0006] A first aspect of the present invention provides an ammonia-blended pulverized coal combustion device, comprising: a pulverized coal burner having a pulverized coal combustion channel; an ammonia burner connected to the pulverized coal burner and at least partially inserted into the pulverized coal combustion channel, having an ammonia combustion channel communicating with the pulverized coal combustion channel; and an ignition burner including a guide pipe, an ignition gun, and a mesh sleeve. The guide pipe is connected to the ammonia burner and has a first inlet end, a first outlet end, and a guide cavity. Both the first inlet end and the first outlet end are connected to the guide cavity. The first outlet end is inserted into the ammonia combustion channel and has multiple outlet holes communicating with the ammonia combustion channel. The mesh sleeve covers the first outlet end and the multiple outlet holes, and has multiple mesh openings. The ignition gun is inserted into the guide cavity and has an ignition end extending out of the first outlet end and the mesh sleeve.

[0007] The ammonia-blended pulverized coal combustion device according to embodiments of the present invention has at least the following beneficial effects: the pulverized coal burner has a pulverized coal combustion channel, an ammonia burner is at least partially inserted into and connected to the pulverized coal combustion channel, a guide pipe is connected to the ammonia burner, and the first outlet end of the guide pipe is inserted into the ammonia combustion channel, and the first outlet end has multiple outlet holes. The ammonia-blended pulverized coal combustion device is further provided with a mesh sleeve, which covers the first outlet end and the multiple outlet holes. The mesh sleeve has multiple mesh openings. An ignition gun is inserted into the guide cavity, and the ignition end of the ignition gun passes through the first outlet hole and the mesh sleeve. In use, the ammonia-blended pulverized coal combustion device can introduce ammonia gas into the first inlet end, allowing the ammonia gas to enter the guide cavity and disperse around the first outlet end after passing through the outlet holes and mesh openings. The arrangement of the outlet holes and mesh openings can effectively increase the ammonia gas concentration. By increasing the flow area and reducing the ammonia flow rate, the ignition end of the ignition gun can ignite the ammonia flowing out of the outlet and mesh to form a primary flame. The mainstream ammonia can be introduced into the ammonia combustion channel of the ammonia burner, where it is ignited by the primary flame to form a secondary flame. The secondary flame can ignite the pulverized coal flow entering the pulverized coal combustion channel, causing the pulverized coal to decompose and burn, thus forming a tertiary flame. Unburned combustibles and the coke remaining after the pulverized coal volatilizes can enter the furnace for complete combustion. In other words, this ammonia-blended pulverized coal combustion device can form a large-scale primary flame through the ignition burner, and ignite the mainstream ammonia through the primary flame to form a secondary flame, thereby increasing the combustion rate of ammonia. The secondary flame can then ignite the pulverized coal flow to form a tertiary flame, thus improving the ignition success rate and reducing carbon dioxide emissions.

[0008] According to some embodiments of the present invention, the end face of the first outlet end is provided with a first through hole, the end face of the mesh sleeve is provided with a second through hole opposite to the first through hole, and the ignition end is disposed through the first through hole and the second through hole.

[0009] According to some embodiments of the present invention, the end face and the peripheral face of the first air outlet are respectively provided with a plurality of air outlet holes.

[0010] According to some embodiments of the present invention, the diameter of the vent hole is 0.3 mm to 3 mm.

[0011] According to some embodiments of the present invention, the first air inlet has a first ammonia inlet and a first combustion-supporting gas inlet communicating with the flow guide cavity;

[0012] And / or, the first air intake end has a first air intake chamber, the first air intake chamber includes a first contraction section and a first expansion section, the two ends of the first expansion section are respectively connected to the first contraction section and the guide chamber, the first contraction section gradually narrows toward the first expansion section, and the first expansion section gradually expands toward the guide chamber.

[0013] According to some embodiments of the present invention, the ammonia burner has a second inlet end communicating with an ammonia combustion channel, and the second inlet end has a second ammonia inlet and a second combustion-supporting gas inlet communicating with the ammonia combustion channel;

[0014] And / or, the ammonia burner has a second inlet end connected to the ammonia combustion flow channel, the second inlet end has a second inlet chamber, the second inlet chamber includes a second contraction section and a second expansion section, the two ends of the second expansion section are respectively connected to the second contraction section and the ammonia combustion flow channel, the second contraction section gradually narrows toward the second expansion section, and the second expansion section gradually expands toward the ammonia combustion flow channel.

[0015] According to some embodiments of the present invention, the pulverized coal burner, the ammonia burner, and the ignition burner are arranged coaxially.

[0016] According to some embodiments of the present invention, the pulverized coal burner has a third inlet end and a third outlet end communicating with the pulverized coal combustion channel, and the pulverized coal burner has a corner between the third inlet end and the third outlet end, and the ammonia burner passes through the corner and is arranged toward the third outlet end.

[0017] The control method of the second aspect of the present invention is applied to the ammonia-blended pulverized coal combustion device of the first aspect. The control method includes:

[0018] A first mixture of ammonia and combustion-supporting gas is introduced into the flow guide cavity, and the ignition end of the ignition gun is controlled to ignite the first mixture flowing out of the outlet and mesh to form a first-stage flame.

[0019] A second mixture of ammonia and combustion-supporting gas is introduced into the ammonia combustion channel, and the second mixture is ignited by a primary flame to form a secondary flame;

[0020] Pulverized coal gas flow is introduced into the pulverized coal combustion channel, and the pulverized coal gas flow is ignited by a secondary flame.

[0021] According to the control method of the present invention, at least the following beneficial effects are achieved: When applied to an ammonia-blended pulverized coal combustion device, the control method allows ammonia gas to be introduced into the first inlet end, so that the ammonia gas enters the guide cavity and disperses around the first outlet end after passing through the outlet hole and mesh. The arrangement of the outlet hole and mesh effectively increases the flow area of ​​the ammonia gas and reduces its flow velocity. The ignition end of the ignition gun can ignite the ammonia gas flowing out of the outlet hole and mesh to form a primary flame. The mainstream ammonia gas can be introduced into the ammonia combustion channel of the ammonia burner, so that the mainstream ammonia gas is... The primary flame is ignited to form the secondary flame, which ignites the coal powder gas flow entering the coal powder combustion channel, causing the coal powder to decompose and burn, thus forming the tertiary flame. Unburned combustibles and coke remaining after the coal powder volatilizes can enter the furnace for complete combustion. This control method can form a large-scale primary flame through the igniter, and ignite the mainstream ammonia gas through the primary flame to form the secondary flame, thereby increasing the combustion rate of ammonia gas. The secondary flame is then used to ignite the coal powder to form the tertiary flame, ensuring the success rate of coal powder ignition and reducing carbon dioxide emissions.

[0022] According to some embodiments of the present invention, a first mixed gas formed by ammonia and combustion-supporting gas is introduced into the flow guide cavity, and the ignition end of the ignition gun is controlled to ignite the first mixed gas flowing out of the outlet and mesh, including: controlling the ratio of ammonia to combustion-supporting gas in the first mixed gas to be 0.9 to 1.1, and controlling the flow rate of the first mixed gas flowing out of the outlet and mesh to be 10 cm / s to 1 m / s;

[0023] Introducing a second mixture of ammonia and combustion-supporting gas into the ammonia combustion channel includes controlling the ratio of ammonia to combustion-supporting gas in the second mixture to be between 0.6 and 1.4.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic diagram of the structure of an ammonia-blended pulverized coal combustion device according to an embodiment of the present invention;

[0027] Figure 2 This is a cross-sectional view of an ammonia-blended pulverized coal combustion device according to an embodiment of the present invention;

[0028] Figure 3 This is a cross-sectional view of the ignition burner of an ammonia-blended pulverized coal combustion device according to an embodiment of the present invention;

[0029] Figure 4This is a partially enlarged view of the first gas outlet end of the ignition burner of an ammonia-blended pulverized coal combustion device according to an embodiment of the present invention.

[0030] Figure 5 This is a cross-sectional view of the ammonia burner of the ignition burner in an ammonia-blended pulverized coal combustion device according to an embodiment of the present invention;

[0031] Figure 6 This is a cross-sectional view of the pulverized coal burner of the ignition burner in an ammonia-blended pulverized coal combustion device according to an embodiment of the present invention;

[0032] Figure 7 This is a flowchart of a control method according to an embodiment of the present invention;

[0033] Figure 8 This is a flowchart illustrating the control method for controlling the mixing ratio of a first gas mixture and a second gas mixture according to an embodiment of the present invention.

[0034] Icon labels:

[0035] 100. Pulverized coal burner; 110. Pulverized coal combustion channel; 120. Third air inlet end; 130. Third air outlet end; 140. Corner; 150. Connecting cylinder; 151. Third flange;

[0036] 200, Ammonia burner; 210, Ammonia combustion channel; 220, Second air inlet; 221, Second ammonia inlet; 222, Second combustion-supporting gas inlet; 223, Second contraction section; 224, Second expansion section; 230, Second air outlet; 240, Second flange;

[0037] 300, Ignition burner; 310, Guide pipe; 311, First air inlet; 3111, First ammonia inlet; 3112, First combustion-supporting gas inlet; 3113, First contraction section; 3114, First expansion section; 312, First air outlet; 3121, Air outlet hole; 313, Guide cavity; 320, Ignition gun; 321, Ignition end; 330, Mesh sleeve; 340, First flange. Detailed Implementation

[0038] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0039] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0040] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0041] In related technologies, since pulverized coal gas flow cannot be directly ignited when the boiler is cold, pulverized coal boilers need to be equipped with oil or natural gas ignition systems or high-power plasma generators, which makes the fuel supply and control system complex and significantly increases investment and operating costs.

[0042] Some coal burners use ammonia burners as igniters, eliminating the need for oil or natural gas as ignition fuels and high-power plasma generators, thus simplifying the system and reducing investment and operating costs. However, ammonia has a low combustion speed and a narrow ignition range, while coal burners have limited volume and area. The ammonia burner used for ignition employs premixed combustion and is located within the coal burner. The flow area and volume of the ammonia burner are limited by the internal installation space of the coal burner, resulting in a high airflow velocity during cold ignition, making flame maintenance difficult and leading to a relatively high probability of ignition failure.

[0043] Reference Figures 1 to 6 As shown, an embodiment of the ammonia-blended pulverized coal combustion device of the present invention includes a pulverized coal burner 100, an ammonia burner 200, and an ignition burner 300.

[0044] The pulverized coal burner 100 has a pulverized coal combustion channel 110, a third air inlet 120 and a third air outlet 130 communicating with the pulverized coal combustion channel 110, and an ammonia burner 200 connected to the pulverized coal burner 100 and at least partially passing through the pulverized coal combustion channel 110. Specifically, the ammonia burner 200 has an ammonia combustion channel 210 communicating with the pulverized coal combustion channel 110. The ammonia burner 200 has a second air inlet 220 and a second air outlet 230 communicating with the ammonia combustion channel 210, with the second air outlet 230 passing through the pulverized coal combustion channel 110 and facing the third air outlet 130.

[0045] Specifically, the ammonia-blended pulverized coal combustion device includes an ignition burner 300, which can use ammonia as ignition fuel. Specifically, the ignition burner 300 includes a guide pipe 310, an ignition gun 320, and a mesh sleeve 330. The guide pipe 310 is connected to the ammonia burner 200 and has a first inlet end 311, a first outlet end 312, and a guide cavity 313. Both the first inlet end 311 and the first outlet end 312 are connected to the guide cavity 313. The guide pipe 310 is connected to the ammonia burner 200, and the first outlet end 312 passes through the ammonia combustion channel 210, and is oriented towards the second outlet end 230.

[0046] Specifically, the first gas outlet end 312 has multiple gas outlet holes 3121. The end face and circumferential surface of the first gas outlet end 312 are respectively provided with multiple gas outlet holes 3121 to achieve gas outlet from multiple directions. The ignition burner 300 also includes a mesh sleeve 330, which covers the first gas outlet end 312 and the multiple gas outlet holes 3121. The mesh sleeve 330 has multiple mesh openings. The mesh sleeve 330 can further divert the gas flowing out of the guide cavity 313 to achieve uniform gas distribution and increase the gas distribution range. The ignition burner 300 also includes an ignition gun 320, which is inserted into the guide cavity 313 and has an ignition end 321. The ignition end 321 extends through the first gas outlet end 312 and the mesh sleeve 330 to ignite the gas flowing out of the gas outlet holes 3121 and the mesh openings.

[0047] In use, the ammonia-blended pulverized coal combustion device can introduce ammonia gas into the first inlet end 311, allowing the ammonia gas to enter the guide cavity 313 and pass through the outlet hole 3121 and the mesh, and then disperse around the first outlet end 312. The outlet hole 3121 and the mesh can effectively increase the flow area of ​​ammonia gas and reduce the flow rate of ammonia gas. The ignition end 321 of the ignition gun 320 can ignite the ammonia gas flowing out of the outlet hole 3121 and the mesh to form a primary flame. The mainstream ammonia gas can be introduced into the ammonia combustion channel 210 of the ammonia burner 200, so that the mainstream ammonia gas is ignited by the primary flame to form a secondary flame. The secondary flame can ignite the pulverized coal gas flow entering the pulverized coal combustion channel 110, so that the pulverized coal decomposes and burns to form a tertiary flame to ignite the pulverized coal. The unburned combustibles and the coke remaining after the pulverized coal volatilizes can enter the furnace for complete combustion.

[0048] The ammonia-blended pulverized coal combustion device can form a large-scale primary flame through the igniter 300, and ignite the mainstream ammonia gas through the primary flame to form a secondary flame, thereby increasing the combustion speed of ammonia gas. The secondary flame can then ignite the pulverized coal gas flow to form a tertiary flame, thereby improving the ignition success rate and reducing carbon dioxide emissions.

[0049] The ammonia-blended pulverized coal combustion device provided in this embodiment of the invention has a high ignition success rate and easy NOx (nitrogen oxides) emission control. This ammonia-blended pulverized coal combustion device can preheat the pulverized coal that has not yet entered the boiler furnace, reduce the heat required for the pulverized coal to burn in the furnace, and at the same time ensure the full combustion of the pulverized coal in the furnace and the combustion stability of the flame in the furnace.

[0050] Understandably, the first outlet end 312 has a first through hole on its end face, and the mesh sleeve 330 has a second through hole opposite to the first through hole on its end face. The ignition end 321 is disposed through the first and second through holes. That is, both the first outlet end 312 and the mesh sleeve 330 have reserved holes for the ignition gun 320 to pass through, so that the ignition end 321 can pass through the guide tube 310 and the mesh sleeve 330, and ignite the airflow flowing out of the outlet 3121 and the mesh.

[0051] Understandably, the end face and circumferential surface of the first gas outlet 312 are respectively provided with multiple gas outlet holes 3121. The gas outlet holes 3121 located on the end face of the first gas outlet 312 can guide the gas along the axial direction of the guide pipe 310, while the gas outlet holes 3121 located on the circumferential surface of the first gas outlet 312 can guide the gas along the radial direction of the guide pipe, so that the gas is distributed between the guide pipe 310 and the inner wall of the ammonia combustion channel 210, which is beneficial to increase the gas distribution range and thus increase the ignition range of ammonia.

[0052] Understandably, the vent 3121 can be a round hole, a square hole, or other shapes, and the shorter side dimension of the vent 3121 should be smaller than the quenching diameter of ammonia. The quenching diameter of ammonia refers to the minimum channel diameter that allows a premixed gas of ammonia (NH3) and air (or oxidant) to maintain stable flame propagation under specific conditions (such as temperature, pressure, and mixing ratio). If the shorter side dimension of the vent 3121 is smaller than this critical value, the flame cannot pass through the vent 3121 to propagate and be maintained, meaning the flame self-extinguishes.

[0053] Preferably, the ammonia-blended pulverized coal combustion device can configure the air outlet 3121 as a circular hole, and set the diameter of the air outlet 3121 to 0.3mm to 3mm. This not only prevents flame propagation but also effectively controls the airflow velocity, thereby improving the ignition success rate. The mesh sleeve 330 has a cylindrical groove, and the first air outlet end 312 is embedded in the groove to achieve the coverage of the first air outlet end 312 by the mesh sleeve 330.

[0054] Understandably, the mesh sleeve 330 is a metal woven mesh, meaning that the mesh sleeve 330 is densely covered with multiple mesh holes. The guide tube 310 can also be made of metal material. Each air outlet 3121 is connected to multiple mesh holes. The diameter of the mesh holes is smaller than the diameter of the air outlet 3121. By covering the first air outlet 312 with the mesh sleeve 330, the flow rate of the gas flowing out of the guide cavity 313 can be further reduced and the gas flow area can be increased. Moreover, due to the high thermal conductivity and radiation heat transfer coefficient of metal fibers, the heating performance of the primary flame formed by the ignition gun 320 on the mainstream ammonia gas is improved, which greatly enhances the combustion stability of the mainstream ammonia gas.

[0055] Understandably, the first air inlet 311 has a first ammonia inlet 3111 and a first combustion-supporting gas inlet 3112 that are connected to the flow guide cavity 313. A first ejector tube is provided at the first ammonia inlet 3111, and ammonia can be introduced into the first ammonia inlet 3111 through the first ejector tube. Through the ejection of high-velocity ammonia, air or other combustion-supporting gases can be guided into the first air inlet 311 from the first combustion-supporting gas inlet 3112, and the ammonia and combustion-supporting gases can be mixed in the flow guide cavity 313 to form a first mixed gas. The first mixed gas can pass through the air outlet 3121 and the mesh to increase the distribution range of the first mixed gas. The ignition end 321 of the ignition gun 320 can ignite the outflowing first mixed gas.

[0056] The ammonia and combustion-supporting gas in the ignition burner 300 have a large flow area for forming the first mixed gas. By controlling the aperture of the outlet 3121 and the mesh, the airflow velocity of the first mixed gas can be effectively reduced, thereby improving the ignition success rate of ammonia. The mixing ratio of ammonia to primary air in the first mixed gas can be controlled from 0.9 to 1.1, giving the first mixed gas a low ignition energy and a high combustion speed, allowing it to be easily ignited by the ignition gun 320. This ammonia-blended pulverized coal combustion device uses premixed combustion, which simplifies the structure of the ignition burner 300, makes the ammonia concentration distribution more uniform, and makes it easier to control the equivalence ratio of the fuel-air mixture, thus resulting in lower NOx emission concentrations.

[0057] Understandably, the first air intake end 311 has a first air intake chamber, which includes a first contraction section 3113 and a first expansion section 3114. The two ends of the first expansion section 3114 are respectively connected to the first contraction section 3113 and the guide chamber 313. The first contraction section 3113 gradually narrows toward the first expansion section 3114, and the first expansion section 3114 gradually expands toward the guide chamber 313.

[0058] When ammonia is introduced into the first ammonia inlet 3111 and combustion-supporting gas is introduced into the first combustion-supporting gas inlet 3112, the first mixed gas formed by ammonia and combustion-supporting gas can first pass through the first contraction section 3113 and then through the first expansion section 3114, thereby accelerating the first mixed gas and forming a complex shock wave system, thus greatly improving the mixing effect of ammonia and combustion-supporting gas.

[0059] Understandably, the ammonia burner 200 has a second air inlet 220 connected to the ammonia combustion channel 210. The second air inlet 220 has a second ammonia inlet 221 and a second combustion-supporting gas inlet 222 connected to the ammonia combustion channel 210. A second ejector tube is provided at the second ammonia inlet 221. Ammonia can be introduced into the second ammonia inlet 221 from the second ejector tube. Through the ejection of high-velocity ammonia, air or other combustion-supporting gases can be guided to enter from the second combustion-supporting gas inlet 222, and the ammonia and combustion-supporting gases can be mixed in the guide cavity 313 to form a second mixed gas. The second mixed gas can be ignited by the ignition of the primary flame to form a secondary flame. The secondary flame is used to ignite the pulverized coal gas flow.

[0060] The ammonia burner 200 has a large flow area for the ammonia and combustion-supporting gas to form the second mixture, thereby improving the ignition success rate of ammonia. The mixing ratio of ammonia to secondary air in the second mixture can be controlled from 0.6 to 1.4, giving the second mixture a lower ignition energy and a higher combustion rate, enabling it to be ignited by the primary flame of the igniter 300, while also ensuring a higher temperature for the secondary ammonia flame. This ammonia-blended pulverized coal combustion device uses premixed combustion, which simplifies the structure of the ammonia burner 200, makes the ammonia concentration distribution more uniform, and makes it easier to control the equivalence ratio of the fuel-air mixture, thus resulting in lower NOx emission concentrations.

[0061] The ammonia-blended pulverized coal combustion device adopts a multi-stage premixed combustion structure, which makes the structure simpler, the ammonia concentration distribution more uniform, and the fuel-air equivalence ratio easier to control, thus resulting in lower NOx emission concentration.

[0062] Understandably, the second air intake end 220 has a second air intake chamber, which includes a second contraction section 223 and a second expansion section 224. The two ends of the second expansion section 224 are respectively connected to the second contraction section 223 and the ammonia combustion channel 210. The second contraction section 223 gradually narrows toward the second expansion section 224, and the second expansion section 224 gradually expands toward the ammonia combustion channel 210.

[0063] When ammonia is introduced into the second ammonia inlet 221 and combustion-supporting gas is introduced into the second combustion-supporting gas inlet 222, the second mixture formed by ammonia and combustion-supporting gas can first pass through the second contraction section 223 and then through the second expansion section 224, thereby accelerating the second mixture and forming a complex shock wave system, thus greatly improving the mixing effect of ammonia and combustion-supporting gas.

[0064] Air introduced from the second combustion gas inlet 222 and ammonia introduced from the second ammonia inlet 221 mix in the ammonia combustion channel 210 to form a second mixed gas. The second mixed gas flows past the vicinity of the mesh sleeve 330 and is heated by the primary flame and ignited by the activating components in the primary flame (low-power flame), thereby forming a high-power ammonia flame (secondary flame) at the second gas outlet 230.

[0065] Understandably, the coaxial arrangement of the pulverized coal burner 100, the ammonia burner 200, and the ignition burner 300 makes the distance between the guide pipe 310 and the peripheral wall of the ammonia combustion channel 210 more uniform, and the distance between the ammonia burner 200 and the pulverized coal combustion channel 110 more uniform. This improves the uniformity of the distribution of ammonia and pulverized coal airflow, increases the ignition range and ignition success rate, and effectively improves the stability of the ammonia-blended pulverized coal combustion device.

[0066] Understandably, the pulverized coal burner 100 has a third air inlet 120 and a third air outlet 130 that are connected to the pulverized coal combustion channel 110. The pulverized coal burner 100 has a corner 140 between the third air inlet 120 and the third air outlet 130. The pulverized coal burner 100 is connected to a connecting cylinder 150 at the corner 140. The connecting cylinder 150 is connected to the pulverized coal combustion channel 110, and the inner axis of the connecting cylinder 150 is coaxial with the axial direction of the third air outlet 130.

[0067] The ammonia burner 200 passes through the corner 140 and is positioned toward the third outlet 130. The connecting cylinder 150 is connected to the ammonia burner 200, thereby providing support for fixing the ammonia burner 200.

[0068] The pulverized coal gas flow (pulverized coal-air mixture) can be introduced into the pulverized coal combustion channel 110 from the third inlet end 120. When the pulverized coal gas flow passes through the high-power ammonia flame near the second outlet end 230, it is heated by the high-temperature secondary flame and decomposes into volatiles containing combustibles such as hydrogen, carbon monoxide, and methane. The combustibles are then ignited. The unburned combustibles and the coke remaining after the pulverized coal volatilization enter the furnace from the third outlet end 130 (not shown in the figure) and continue to burn in the furnace until it is completely burned.

[0069] Understandably, specifically, the outer periphery of the connecting cylinder 150 is provided with a third flange 151, while the outer periphery of the ammonia burner 200 is provided with a second flange 240. The user can achieve a fixed connection between the ammonia burner 200 and the pulverized coal burner 100 by passing a threaded connector through the second flange 240 and the third flange 151.

[0070] The ammonia burner 200 has an installation port communicating with the ammonia combustion channel 210 at one end facing away from the pulverized coal burner 100, and an installation hole around the installation port. The ignition burner 300 has a first flange 340 on its outer periphery. The ignition burner 300 passes through the installation port, and the first flange 340 abuts against the end face of the ammonia burner 200. The user can achieve a fixed connection between the ignition burner 300 and the ammonia burner 200 by passing a threaded connector through the first flange 340 and the installation hole.

[0071] Understandably, the thermal power of the ignition burner 300 is 5-50kW, the thermal power of the ammonia burner 200 is 100kW-1MW, and the thermal power of the pulverized coal burner 100 is 12-60MW, in order to ensure multi-stage ignition of the flame and improve the flame propagation speed and ignition success rate.

[0072] One embodiment of the control method of the present invention, using the ammonia-blended pulverized coal combustion device of any of the above embodiments, includes the following steps:

[0073] In step S100, a first mixture of ammonia and combustion-supporting gas is introduced into the flow guide cavity 313, and the ignition end 321 of the ignition gun 320 is controlled to ignite the first mixture flowing out of the outlet 3121 and the mesh to form a first-stage flame.

[0074] In step S200, a second mixture of ammonia and combustion-supporting gas is introduced into the ammonia combustion channel 210, and the second mixture is ignited by a primary flame to form a secondary flame.

[0075] In step S300, pulverized coal gas flow is introduced into the pulverized coal combustion channel 110, and the pulverized coal gas flow is ignited by a secondary flame.

[0076] In step S100, the first inlet end 311 has a first ammonia inlet 3111 and a first combustion-supporting gas inlet 3112 communicating with the guide cavity 313. A first ejector tube is provided at the first ammonia inlet 3111, allowing ammonia gas to enter through the ejector tube. The high-velocity ammonia gas ejection guides air or other combustion-supporting gases to enter through the first combustion-supporting gas inlet 3112, causing the ammonia gas and combustion-supporting gas to mix within the guide cavity 313 to form a first mixed gas. This first mixed gas can pass through the outlet hole 3121 and the mesh to increase its distribution range. The ignition end 321 of the ignition gun 320 can ignite the outflowing first mixed gas. The ignition burner 300 has a large flow area for the ammonia gas and combustion-supporting gas to form the first mixed gas, and by controlling the aperture of the outlet hole 3121 and the mesh, the airflow velocity of the first mixed gas can be effectively reduced, thereby improving the ignition success rate of the ammonia gas. The mixing ratio of ammonia to primary air in the first mixture can be controlled between 0.9 and 1.1, giving the first mixture a low ignition energy and a high combustion rate, allowing it to be easily ignited by the ignition gun 320. This control method employs premixed combustion, which simplifies the structure of the ignition burner 300, results in a more uniform ammonia concentration distribution, and makes it easier to control the equivalence ratio of the fuel-air mixture, thus leading to lower NOx emission concentrations.

[0077] In step S200, the air introduced from the second combustion gas inlet 222 and the ammonia introduced from the second ammonia inlet 221 are mixed in the ammonia combustion channel 210 to form a second mixed gas. The second mixed gas flows through the vicinity of the mesh sleeve 330 and is heated by the primary flame and ignited by the activating components in the primary flame (low-power flame), thereby forming a high-power secondary flame (ammonia flame) at the second gas outlet 230.

[0078] In step S300, the pulverized coal gas flow (pulverized coal-air mixture) can be introduced into the pulverized coal combustion channel 110 from the third inlet end 120. When the pulverized coal gas flow passes through the high-power ammonia flame near the second outlet end 230, it is heated by the high-temperature secondary flame and decomposes into volatiles containing combustibles such as hydrogen, carbon monoxide, and methane. The combustibles are then ignited. The unburned combustibles and the coke remaining after the pulverized coal volatilization enter the furnace (not shown in the figure) from the third outlet end 130 and continue to burn in the furnace until burnout.

[0079] The control method provided in this invention has a high ignition success rate and easy NOx (nitrogen oxides) emission control. This control method can preheat the pulverized coal that has not yet entered the boiler furnace, reduce the heat required for the pulverized coal to burn in the furnace, and at the same time ensure the full combustion of the pulverized coal in the furnace and the combustion stability of the flame in the furnace.

[0080] Understandably, in step S100, the control method introduces a first mixture of ammonia and combustion-supporting gas into the guide cavity 313, and controls the ignition end 321 of the ignition gun 320 to ignite the first mixture flowing out of the outlet 3121 and the mesh, including the following steps:

[0081] In step S110, the ratio of ammonia to combustion-supporting gas in the first mixed gas is controlled to be 0.9 to 1.1, and the speed at which the first mixed gas flows out of the outlet 3121 and the mesh is controlled to be 10 cm / s to 1 m / s.

[0082] In step S110, the ammonia and combustion-supporting gas in the ignition burner 300 form a large flow area for the first mixed gas. By controlling the aperture of the outlet 3121 and the mesh, the airflow velocity of the first mixed gas can be effectively reduced, thereby improving the ignition success rate of ammonia. The mixing ratio of ammonia to primary air in the first mixed gas can be controlled between 0.9 and 1.1, giving the first mixed gas a low ignition energy and a high combustion speed, allowing it to be easily ignited by the ignition gun 320. This ammonia-blended pulverized coal combustion device uses premixed combustion, which simplifies the structure of the ignition burner 300, makes the ammonia concentration distribution more uniform, and makes it easier to control the equivalence ratio of the fuel-air mixture, thus resulting in lower NOx emission concentrations.

[0083] This control method utilizes the aperture of the vent 3121 and the aperture of the mesh to control the flow rate of the first ammonia inlet 3111 and the first combustion-supporting gas inlet 3112. This allows control of the flow rate of the first mixed gas through the vent 3121 and the mesh, and controls the flow rate to 10 cm / s to 1 m / s. This effectively reduces the flow rate of the first mixed gas, thereby improving the ignition success rate of ammonia.

[0084] Understandably, in step S200, the control method introduces a second mixture of ammonia and combustion-supporting gas into the ammonia combustion channel 210, including the following steps:

[0085] In step S210, the ratio of ammonia to combustion-supporting gas in the second mixture is controlled to be 0.6 to 1.4.

[0086] In step S210, the control method controls the mixing ratio of the second mixture to give it a lower ignition energy and a higher combustion rate, enabling it to be ignited by the primary flame of the igniter 300, while simultaneously giving the secondary ammonia flame a higher temperature. This ammonia-blended pulverized coal combustion device employs premixed combustion, resulting in a simpler structure for the ammonia burner 200, a more uniform ammonia concentration distribution, and easier control of the fuel-air equivalence ratio, thus leading to lower NOx emission concentrations.

[0087] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0088] This invention is described in terms of flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0089] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0091] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An ammonia-blended pulverized coal combustion device, characterized in that, include: A pulverized coal burner (100) having a pulverized coal combustion channel (110); An ammonia burner (200) is connected to the pulverized coal burner (100) and is at least partially inserted into the pulverized coal combustion channel (110), and has an ammonia combustion channel (210) communicating with the pulverized coal combustion channel (110); An ignition burner (300) includes a guide pipe (310), an ignition gun (320), and a mesh sleeve (330). The guide pipe (310) is connected to the ammonia burner (200). The guide pipe (310) has a first inlet end (311), a first outlet end (312), and a guide cavity (313). The first inlet end (311) and the first outlet end (312) are both connected to the guide cavity (313). The first outlet end (312) passes through the ammonia combustion channel (210). 312) has multiple air outlets (3121), the air outlets (3121) are connected to the ammonia combustion channel (210), the mesh sleeve (330) covers the first air outlet (312) and covers the multiple air outlets (3121), the mesh sleeve (330) has multiple mesh holes, the ignition gun (320) passes through the guide cavity (313), the ignition gun (320) has an ignition end (321), the ignition end (321) passes through the first air outlet (312) and the mesh sleeve (330).

2. The ammonia-blended pulverized coal combustion device according to claim 1, characterized in that: The end face of the first air outlet (312) is provided with a first through hole, and the end face of the mesh sleeve (330) is provided with a second through hole opposite to the first through hole. The ignition end (321) is disposed through the first through hole and the second through hole.

3. The ammonia-blended pulverized coal combustion device according to claim 2, characterized in that: The first air outlet end (312) has a plurality of air outlet holes (3121) on its end face and circumferential surface, respectively.

4. The ammonia-blended pulverized coal combustion device according to claim 3, characterized in that: The diameter of the air outlet (3121) is 0.3 mm to 3 mm.

5. The ammonia-blended pulverized coal combustion device according to claim 1, characterized in that: The first air inlet (311) has a first ammonia inlet (3111) and a first combustion-supporting gas inlet (3112) communicating with the flow guide cavity (313); And / or, the first air intake end (311) has a first air intake chamber, the first air intake chamber including a first contraction section (3113) and a first expansion section (3114), the two ends of the first expansion section (3114) are respectively connected to the first contraction section (3113) and the guide chamber (313), the first contraction section (3113) gradually narrows toward the first expansion section (3114), and the first expansion section (3114) gradually expands toward the guide chamber (313).

6. The ammonia-blended pulverized coal combustion device according to claim 1, characterized in that, The ammonia burner (200) has a second inlet end (220) communicating with the ammonia combustion channel (210), and the second inlet end (220) has a second ammonia inlet (221) and a second combustion-supporting gas inlet (222) communicating with the ammonia combustion channel (210); And / or, the ammonia burner (200) has a second inlet end (220) communicating with the ammonia combustion channel (210), the second inlet end (220) having a second inlet chamber, the second inlet chamber including a second contraction section (223) and a second expansion section (224), the two ends of the second expansion section (224) communicating with the second contraction section (223) and the ammonia combustion channel (210) respectively, the second contraction section (223) gradually narrowing toward the second expansion section (224), and the second expansion section (224) gradually expanding toward the ammonia combustion channel (210).

7. The ammonia-blended pulverized coal combustion device according to claim 1, characterized in that: The pulverized coal burner (100), the ammonia burner (200), and the ignition burner (300) are arranged coaxially.

8. The ammonia-blended pulverized coal combustion device according to claim 1, characterized in that: The pulverized coal burner (100) has a third air inlet (120) and a third air outlet (130) communicating with the pulverized coal combustion channel (110). The pulverized coal burner (100) has a corner (140) between the third air inlet (120) and the third air outlet (130). The ammonia burner (200) passes through the corner (140) and is arranged towards the third air outlet (130).

9. A control method, characterized in that, The control method, applied to the ammonia-blended pulverized coal combustion device as described in any one of claims 1 to 8, comprises: A first mixture of ammonia and combustion-supporting gas is introduced into the flow guide cavity (313), and the ignition end (321) of the ignition gun (320) is controlled to ignite the first mixture flowing out of the outlet (3121) and the mesh to form a first-stage flame. A second mixture of ammonia and combustion-supporting gas is introduced into the ammonia combustion channel (210), and the second mixture is ignited by the primary flame to form a secondary flame; A coal powder gas flow is introduced into the coal powder combustion channel (110), and the coal powder gas flow is ignited by the secondary flame.

10. The control method according to claim 9, characterized in that: The first mixture of ammonia and combustion-supporting gas is introduced into the flow guide cavity (313), and the ignition end (321) of the ignition gun (320) is controlled to ignite the first mixture flowing out of the outlet (3121) and the mesh, including: controlling the ratio of ammonia to combustion-supporting gas in the first mixture to be 0.9 to 1.1, and controlling the speed at which the first mixture flows out of the outlet (3121) and the mesh to be 10 cm / s to 1 m / s; The process of introducing a second mixture of ammonia and combustion-supporting gas into the ammonia combustion channel (210) includes controlling the ratio of ammonia to combustion-supporting gas in the second mixture to be between 0.6 and 1.4.

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