A boiler using flue gas and oxygen premixing combustion to reduce nitrogen oxides

Abstract

The application discloses a boiler using flue gas and oxygen premixed combustion-supporting to reduce nitrogen oxides, and belongs to the technical field of combustion, which comprises a boiler body, a combustion-supporting pipe and a flue gas pipe; the flue gas pipe is provided with a stirring device and a suppressing device; the stirring device comprises a horizontal plate, a first motor, a gas conveying pipe and a stirring cylinder; the application is provided with the stirring device, so that the sliding rod rotationally connected with the connecting rod repeatedly moves in the through hole of the stirring cylinder, the gap changeable air flow is repeatedly pushed by the push plate, the push plate is just located at the outer end of the stirring cylinder, the air flow generated by the push plate can interfere with the rotating air flow, so that the coal powder rotating with the rotating air flow is separated from the control of the rotating air flow, the separation efficiency of the coal powder is effectively improved, the coal powder burns together with most of the coal powder under the action of the suppressing device, and the generation of nitrogen oxides can be suppressed.

Description

Technical Field

[0001] This invention belongs to the field of combustion technology, specifically relating to a boiler that uses premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides. Background Technology

[0002] Boilers in thermal power plants have long faced the problem of "high sulfur, high ash, high nitrogen oxides, and high flue gas temperature" due to coal procurement and furnace characteristics. Achieving ultra-low emissions will encounter many unprecedented challenges, necessitating research and modification of low-NOx combustion control technology.

[0003] The boiler currently in use has the following problems:

[0004] 1. Due to the uneven quality of pulverized coal, there is a distinction between coarse and light pulverized coal. When coarse and light pulverized coal are mixed together, the pulverized coal cannot be fully burned, resulting in a large amount of nitrogen oxides, which does not meet the low-NOx combustion standard.

[0005] 2. Existing boilers typically use air to transport pulverized coal. Since air contains nitrogen, the combustion of pulverized coal in the boiler will produce thermal nitrogen oxides, further increasing the generation of nitrogen oxides. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a boiler that uses flue gas and oxygen premixed to assist combustion and reduce nitrogen oxides, so as to solve the technical problem that the coal powder cannot be fully burned due to the mixing of coarse and light coal powder.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a boiler that uses premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides, comprising a boiler body; a combustion-aiding pipe connected to one side of the boiler body, and a flue gas pipe connected to the other side; an inhibition device capable of igniting pulverized coal and suppressing nitrogen oxide production is provided at one end of the flue gas pipe near the boiler body; a stirring device for improving the mixing degree of pulverized coal and oxygen is provided near the inlet end of the flue gas pipe; the stirring device includes a horizontal plate radially disposed on the inner wall of the flue gas pipe; a first motor is vertically disposed on the horizontal plate; and a gas supply is connected to the power end of the first motor. The pipe has several stirring drums evenly distributed along its circumferential sidewalls along its length. Each stirring drum is connected to the gas supply pipe. A support plate is vertically connected to the inner wall of the stirring drum at the end away from the gas supply pipe. A turntable is rotatably connected to the support plate via a second motor. A rotating shaft perpendicular to the turntable is located on the turntable at a position away from the center. A through hole is opened on the inner wall of the stirring drum at the end away from the gas supply pipe. A sliding rod is slidably connected to the through hole. A push plate is connected to the end of the sliding rod away from the gas supply pipe, and a connecting rod is rotatably connected to the other end. The free end of the connecting rod is rotatably connected to the rotating shaft.

[0009] Furthermore, a gas supply device for supplying oxygen to the gas supply pipe is provided on one side of the flue gas pipe; each stirring drum is provided with an intermittent jet device; the intermittent jet device includes a slide tube slidably connected inside the stirring drum; the tube wall of the slide tube near the inner wall of the flue gas pipe is connected to the tube wall of the stirring drum by several springs; several enlarged holes are opened on the circumferential side wall of the slide tube; several spray holes are opened on the circumferential side wall of the stirring drum; when the slide tube compresses the spring, each enlarged hole can communicate with the corresponding spray hole.

[0010] Furthermore, the gas supply pipe has several radially arranged fixed plates evenly connected to its circumferential sidewalls near the first motor; a coal scraping device is provided at the end of the fixed plate away from the first motor; the coal scraping device includes a sliding groove and a strip groove formed in the fixed plate; one side of the strip groove is connected to the sliding groove, and the other side passes through the fixed plate; a slider is slidably connected in the sliding groove through a first tension spring; a third motor located in the strip groove is connected to the slider; a coal scraping rod is coaxially connected to the power end of the third motor; several scraping grooves are evenly formed on the circumferential sidewalls of the coal scraping rod; a scraper is slidably connected in each scraping groove through a second tension spring; a button for controlling the rotation of the third motor is provided on the sidewall of the sliding groove away from the gas supply pipe.

[0011] Furthermore, the gas delivery device includes an oxygen tank located on one side of the flue gas pipe; one end of the horizontal plate passes through the flue gas pipe and has an air inlet; the oxygen tank is connected to the air inlet end of the air inlet; the first motor is connected to the gas delivery pipe via a rotary joint; the air outlet end of the air inlet is connected to the inlet end of the rotary joint via a gas delivery pipe; and the outlet end of the rotary joint is connected to the gas delivery pipe.

[0012] Furthermore, the flue gas pipe is inverted L-shaped; the inlet end of the flue gas pipe has an enlarged section; the outlet end of the flue gas pipe is connected to a light pulverized coal pipe and a coarse pulverized coal pipe, which are respectively connected to the boiler body; the intersection of the light pulverized coal pipe and the coarse pulverized coal pipe is rounded; the pipe wall of the light pulverized coal pipe away from the flue gas pipe has a constricted section; the suppression device is located between the coarse pulverized coal pipe and the constricted section.

[0013] Furthermore, the suppression device includes a connecting pipe and a coarse ignition pipe disposed inside the coarse pulverized coal pipe; the connecting pipe is connected to the coarse ignition pipe; an ignition nozzle is provided on the side wall of the connecting pipe; the connecting pipe is connected to a fuel oil pipe; the fuel oil pipe is connected to a fuel oil tank disposed on one side of the flue gas pipe; control valves are provided at the end of the fuel oil pipe connected to the connecting pipe and on the ignition nozzle.

[0014] Furthermore, a fourth motor is installed at the junction of the flue gas pipe, the light pulverized coal pipe, and the coarse pulverized coal pipe; the power end of the fourth motor is coaxially connected to a connecting shaft; three filter plates are evenly distributed around the connecting shaft; and several filter holes are opened on the filter plates.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. The second motor drives the turntable to rotate, causing the slide rod, which is rotatably connected to the connecting rod, to move repeatedly within the through hole of the mixing drum. This causes the push plate to repeatedly push the airflow, which generates gap changes. Since the push plate is located at the outer end of the mixing drum, the airflow generated by the push plate can interfere with the rotating airflow, thereby causing the coal powder rotating with the rotating airflow to break away from the control of the rotating airflow, effectively improving the separation efficiency of the coal powder. Combined with the suppression device located at the outlet end of the flue gas pipe, it can ignite the coal powder while reducing the generation of nitrogen oxides.

[0017] 2. When the first motor drives the gas delivery pipe to rotate, the slide pipe compresses the spring due to centrifugal force. Simultaneously, because the first motor is a variable-speed motor with constantly changing speed, the centrifugal force on the slide pipe is not constant. This results in intermittent communication between the slide pipe's expansion orifice and the nozzle, achieving intermittent gas injection. The intermittently injected oxygen can fully mix with the coarse and lean pulverized coal, thereby lowering the ignition point of the coarse and lean pulverized coal. Furthermore, compared to continuous gas injection, intermittent gas injection allows the airflow between the nozzles to remain variable, thus cleaning the pulverized coal adhering to the side wall of the mixing drum with the airflow generated each time gas is injected. Since flue gas is used instead of traditional air to transport pulverized coal, and the oxygen introduced through the gas delivery pipe reduces the amount of nitrogen entering when using air for transport, it also suppresses the thermal nitrogen oxides produced during nitrogen combustion within the boiler body, thereby reducing nitrogen oxide production.

[0018] 3. When the third motor rotates, it will drive the coal dust scraped off the inner wall of the flue pipe to generate a rotating airflow, which will cause the scraped coal dust to gather together again. In conjunction with the repeatedly moving push plate, the airflow generated by the push plate can interfere with this part of the coal dust, so that it will burn together with most of the coal dust under the action of the suppression device, while reducing the generation of nitrogen oxides.

[0019] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0021] Figure 1 This is a schematic diagram of the boiler of the present invention;

[0022] Figure 2 This is a longitudinal sectional view of the flue gas pipe of the present invention;

[0023] Figure 3 For the present invention Figure 2 A magnified view of a section at point A in the middle;

[0024] Figure 4 For the present invention Figure 2 A magnified view of a section at point B.

[0025] The following components are labeled in the attached diagram: Boiler body 1, Combustion aid pipe 2, Flue gas pipe 3, Horizontal plate 4, First motor 5, Gas supply pipe 6, Stirring drum 7, Connecting hole 8, Connecting rod 9, Support plate 10, Turntable 11, Slide rod 12, Push plate 13, Slide tube 14, Spring 15, Expanding hole 16, Spray hole 17, Fixing plate 18, Slide groove 19, Strip groove 20, Sliding block 21, Coal scraper 22, Scraper 23, Button 24, First tension spring 25, Second tension spring 26, Oxygen tank 27, Rotary joint 28, Gas supply pipe 29, Expanding hole section 30, Light coal powder pipe 31, Coarse coal powder pipe 32, Narrowing section 33, Filter plate 34, Fuel oil pipe 35, Fuel oil tank 36, Connecting pipe 37, Ignition nozzle 38. Detailed Implementation

[0026] like Figures 1-4 As shown, this invention provides a boiler that uses premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides, including a boiler body 1; the boiler body 1 is divided into a main combustion zone and a burnout zone from bottom to top; a combustion-aiding pipe 2 is connected to the right side of the boiler body 1, and a flue gas pipe 3 is connected to its left side, the lower end of the flue gas pipe 3 is the inlet end, and the right end of the flue gas pipe 3 is the outlet end entering the main combustion zone of the boiler body 1; an inhibition device capable of igniting pulverized coal and suppressing the generation of nitrogen oxides is provided at the outlet end of the flue gas pipe 3; a stirring device for improving the mixing degree of pulverized coal and oxygen is provided near the inlet end of the flue gas pipe 3; as shown Figure 2 As shown, the stirring device includes a horizontal plate 4 radially disposed on the inner wall of the flue gas pipe 3; a first motor 5 is vertically disposed on the lower surface at the center of the horizontal plate 4, the first motor 5 being a variable speed motor; a gas supply pipe 6 is connected to the power end of the first motor 5, and the lower end of the gas supply pipe 6 is sealed; several stirring cylinders 7 are evenly distributed along the circumferential sidewalls along the length of the gas supply pipe 6; a connection hole 8 is opened horizontally at the corresponding position of the gas supply pipe 6; each stirring cylinder 7 is connected to the gas supply pipe 6 through the connection hole 8; as shown Figure 3 As shown, a support plate 10 is vertically connected to the inner wall of the mixing drum 7 at the end away from the gas supply pipe 6; a turntable 11 parallel to the support plate 10 is rotatably connected to the support plate 10 via a vertically installed second motor; a rotating shaft perpendicular to the turntable 11 is provided on the turntable 11 at a position away from the center; a through hole is opened in the horizontal direction on the inner wall of the mixing drum 7 at the end away from the gas supply pipe 6; a sliding rod 12 is slidably connected in the through hole; a push plate 13 is connected to one end of the sliding rod 12 away from the gas supply pipe 6, and a connecting rod 9 is rotatably connected to the other end; the free end of the connecting rod 9 is rotatably connected to the rotating shaft.

[0027] The principles and effects of the above technical solution:

[0028] The first motor 5 is started to drive the gas pipe 6 to rotate, thereby driving the stirring drum 7 to stir the coal powder entering from the inlet end of the flue gas pipe 3. During the stirring process, the stirring drum 7 impacts the coal powder, which can separate the coarse and light coal powder mixed together. After being stirred and separated, most of the coal powder can flow with the airflow to the outlet end of the flue gas pipe 3. However, during the stirring process, the rotation of the stirring drum 7 will generate a rotating airflow, which will cause some of the coal powder that has been separated from the coarse and light coal powder to gather together and rotate with the rotating airflow. At the same time, the coal powder that has not been stirred and separated will rotate with the rotating airflow. To solve this problem, the second motor is started, which drives the turntable 11 to rotate. This causes the slide rod 12, which is rotatably connected to the connecting rod 9, to move repeatedly within the through hole of the mixing drum 7. This causes the push plate 13 to repeatedly push the airflow, which generates gap changes. Since the push plate 13 is located at the outer end of the mixing drum 7, the airflow generated by the push plate 13 can interfere with the rotating airflow, thereby causing the coal powder rotating with the rotating airflow to break away from the control of the rotating airflow. This effectively improves the separation efficiency of the coal powder. Combined with the suppression device located at the outlet end of the flue gas pipe 3, it can ignite the coal powder while reducing the generation of nitrogen oxides.

[0029] In this embodiment, a gas supply device for supplying oxygen to the gas supply pipe 6 is provided on the left side of the flue gas pipe 3; such as Figure 3 As shown, each stirring drum 7 is equipped with an intermittent jetting device; the intermittent jetting device includes a slide tube 14 slidably connected inside the stirring drum 7; the outer side wall of the slide tube 14 contacts the inner side wall of the stirring drum 7; the tube wall of the slide tube 14 near the inner wall of the flue gas pipe 3 is connected to the tube wall of the stirring drum 7 by several springs 15; several enlarged holes 16 are opened on the circumferential side wall of the slide tube 14 away from the axis of the slide tube 14; several spray holes 17 are opened on the circumferential side wall of the stirring drum 7; when the slide tube 14 compresses the spring 15, each enlarged hole 16 can communicate with the corresponding spray hole 17.

[0030] The principles and effects of the above technical solution:

[0031] Before pulverized coal is fed into flue gas pipe 3, oxygen is first introduced into gas pipe 6 through gas conveying device. After a period of "preheating", the stirring drum 7 and gas pipe 6 are filled with oxygen, and then pulverized coal is introduced into flue gas pipe 3.

[0032] When the first motor 5 drives the gas delivery pipe 6 to rotate, the slide pipe 14 compresses the spring 15 due to centrifugal force. Simultaneously, since the first motor 5 is a variable-speed motor, its rotational speed is constantly changing, and the centrifugal force on the slide pipe 14 is not constant. When the centrifugal force is greater than the elastic force of the spring 15, the slide pipe 14 moves away from the gas delivery pipe 6; when the centrifugal force is less than the elastic force of the spring 15, the slide pipe 14 moves closer to the gas delivery pipe 6. This results in intermittent communication between the expansion hole 16 of the slide pipe 14 and the nozzle 17, leading to intermittent gas ejection. The small amount of oxygen ejected intermittently can separate coarse and fine oxygen. The pulverized coal is thoroughly mixed, thereby lowering the ignition point of coarse and light pulverized coal. At the same time, compared to continuous jetting, intermittent jetting allows the airflow between the nozzles 17 to be in a changing state, so that the airflow generated each time jetting cleans the pulverized coal adhering to the side wall of the mixing drum 7. In addition, intermittent jetting can also reduce oxygen consumption and save energy. Since flue gas is used instead of traditional air to transport pulverized coal, and oxygen is introduced through the gas supply pipe 6, the amount of nitrogen entering when transporting with air is reduced, and the thermal nitrogen oxides generated when nitrogen is burned in the boiler body 1 are suppressed, thereby reducing the generation of nitrogen oxides.

[0033] In this embodiment, as Figure 2 As shown, a plurality of radially arranged fixing plates 18 are evenly connected to the circumferential sidewall of the gas pipe 6 near the first motor 5; there is a gap between the end of the fixing plate 18 away from the first motor 5 and the pipe wall of the flue gas pipe 3; a coal scraping device is provided on the lower sidewall of the end of the fixing plate 18 away from the first motor 5; as shown Figure 4 As shown, the coal scraping device includes a chute 19 and a strip groove 20 horizontally opened in the fixed plate 18; the horizontal dimension of the strip groove 20 is smaller than that of the chute 19; the upper side of the strip groove 20 is connected to the chute 19, and its lower side penetrates the fixed plate 18; a slider 21 is slidably connected in the chute 19 by a first tension spring 25 set on the side wall near the gas pipe 6; a third motor located in the strip groove 20 is vertically connected to the lower side wall of the slider 21; the rotation direction of the third motor is opposite to that of the first motor 5; a coal scraping rod 22 is coaxially connected to the power end of the third motor; several scraping grooves are evenly opened on the circumferential side wall of the coal scraping rod 22; a scraper 23 is slidably connected in each scraping groove by a second tension spring 26; there is a gap between the scraper 23 and the push plate 13; a button 24 for controlling the rotation of the third motor is provided on the side wall of the chute 19 away from the gas pipe 6; when the slider 21 touches the button 24, the third motor starts to rotate; when the slider 21 does not touch the button 24, the third motor stops rotating.

[0034] The principles and effects of the above technical solution:

[0035] During the mixing of pulverized coal, coarse and fine pulverized coal inevitably adhere to the pipe wall, preventing this portion from burning. To solve this problem, the first motor 5 drives the gas pipe 6 to rotate, causing the fixed plate 18 to rotate. Due to the rotation of the first motor 5, which is a variable speed motor, the intermittent centrifugal force causes the slider 21 to intermittently move away from the first spring 15 and contact the button 24, intermittently activating the button 24. This controls the rotation of the third motor. The centrifugal force generated by the rotation allows the scraper 23 to extend its scraper groove and contact the inner wall of the flue gas pipe 3, scraping off the pulverized coal adhering to the pipe wall. This allows this portion of pulverized coal to enter the boiler body 1 along with most of the pulverized coal for combustion, improving the pulverized coal combustion rate. At the same time, when the third motor rotates, the pulverized coal scraped from the inner wall of the flue gas pipe 3 generates a rotating airflow, causing the scraped pulverized coal to gather together. In conjunction with the repeatedly moving pusher plate 13, the airflow generated by the pusher plate 13 can interfere with this portion of pulverized coal, causing it to be ignited and burned along with most of the pulverized coal by the suppression device.

[0036] In this embodiment, as Figure 1 , 2 As shown, the gas supply device includes an oxygen tank 27 located on one side of the flue gas pipe 3; one end of the horizontal plate 4 passes through the flue gas pipe 3 and has an air inlet channel that is first horizontal and then vertical; the oxygen tank 27 is connected to the air inlet end at the left end of the air inlet channel; the first motor 5 is connected to the gas supply pipe 6 through a rotary joint 28; the air outlet end at the lower end of the air inlet channel is connected to the inlet end of the rotary joint 28 through a gas supply pipe 29; the outlet end of the rotary joint 28 is connected to the gas supply pipe 6.

[0037] The principles and effects of the above technical solution:

[0038] Oxygen is supplied to the air intake through the oxygen tank 27. The oxygen enters the air supply pipe 29 through the outlet of the air intake; then it enters the air delivery pipe 6 through the rotary joint 28, and finally enters each mixing drum 7 through the connection hole 8 and is sprayed out through the spray hole 17. While stirring and separating coarse and light coal powder, oxygen is injected, which can improve the mixing rate of oxygen and coal powder, reduce the ignition point of coal powder, and improve the combustion rate.

[0039] In this embodiment, as Figure 2 As shown, the flue gas pipe 3 is inverted L-shaped; the inlet end of the flue gas pipe 3 has an enlarged section 30; the outlet end of the flue gas pipe 3 is connected to a light pulverized coal pipe 31 and a coarse pulverized coal pipe 32 located below it, both of which are connected to the boiler body 1; the intersection of the light pulverized coal pipe 31 and the coarse pulverized coal pipe 32 is rounded; the pipe wall of the light pulverized coal pipe 31 away from the flue gas pipe 3 has a constriction section 33; the suppression device is located between the coarse pulverized coal pipe 32 and the constriction section 33.

[0040] The principles and effects of the above technical solution:

[0041] After the pulverized coal is stirred and passes through the corner of the inverted L-shaped flue gas pipe 3, the light pulverized coal is separated from the heavy pulverized coal due to its lighter weight. The two pulverized coals are then ignited separately by the suppression device, which also suppresses the generation of nitrogen oxides. The enlarged section 30 at the inlet end can increase the amount of pulverized coal stirred per unit time. The arc transition makes it easier for the pulverized coal to pass through and reduces the damage caused by pulverized coal impact. The constriction section 33 can accelerate the speed at which the light pulverized coal enters the boiler body 1, thereby making the light pulverized coal more dispersed when it is injected into the boiler body 1.

[0042] In this embodiment, as Figure 1 , 2 As shown, the suppression device includes a vertically arranged connecting pipe 37 and a coarse ignition pipe coaxially arranged inside the coarse pulverized coal pipe 32; the lower end of the connecting pipe 37 passes through the coarse pulverized coal pipe 32 and communicates with the coarse ignition pipe; a fuel oil pipe 35 is connected to the rear side wall of the connecting pipe 37; an ignition nozzle 38 is provided on the rear side wall of the coarse pulverized coal pipe 32; the fuel oil pipe 35 is connected to a fuel oil tank 36 located on one side of the flue gas pipe 3; a control valve (not shown in the figure) is provided at the end of the fuel oil pipe 35 that communicates with the connecting pipe 37 and at the end of the ignition nozzle 38 located outside the coarse pulverized coal pipe 32.

[0043] The principles and effects of the above technical solution:

[0044] Fuel from fuel tank 36 is pumped into fuel pipe 35 by an oil pump. Then, the control valve on connecting pipe 37 is closed, and fuel enters the coarse ignition pipe through connecting pipe 37, which can reduce the ignition temperature in coarse pulverized coal pipe 32. The control valve at ignition nozzle 38 is opened, and ignition is carried out using an existing ignition device, thereby igniting the pulverized coal in the coarse ignition pipe. This ignites the pulverized coal with a small amount of oxygen supplied by the gas delivery device, creating an oxygen-rich micro-oil combustion state in the coarse ignition pipe. This ignites the pulverized coal in the entire coarse pulverized coal pipe 32. After the small amount of micro-oil and oxygen are consumed, a severe lack of oxygen forms in the coarse pulverized coal pipe 32. Oxygen forms a reducing pulverized coal flue gas flow, thereby inhibiting the generation of nitrogen oxides. The reducing pulverized coal flue gas flow ejected from the right end of the coarse pulverized coal pipe 32 enters the main combustion zone of the boiler body 1. Since the main combustion zone is far from the combustion-supporting pipe 2 at the upper end of the boiler body, the air is relatively thin, thus forming a reducing environment, further inhibiting the generation of nitrogen oxides. The reducing flue gas flow enters the burnout zone of the boiler body 1, and combustion-supporting air is introduced into the burnout zone through the combustion-supporting pipe 2 to ensure complete combustion of pulverized coal. The control valve installed on the connecting pipe 37 can prevent the flame from returning to the fuel oil tank 36 along the fuel oil pipe 36 when the ignition equipment is ignited.

[0045] In this embodiment, as Figure 2As shown, a fourth motor is installed in the front and rear directions at the junction of the flue gas pipe 3, the light coal powder pipe 31, and the coarse coal powder pipe 32; the power end of the fourth motor is coaxially connected to a connecting shaft; three filter plates 34 are evenly distributed around the connecting shaft; the filter plates 34 have several filter holes that allow light coal powder to pass through, and the fourth motor rotates counterclockwise.

[0046] The principles and effects of the above technical solution:

[0047] The filter holes allow the light coal powder flowing from above to pass through and enter the light coal powder pipe 31; as the fourth motor rotates counterclockwise, the filter plate 34 can intercept the coarse coal powder. When the coarse coal powder rotates counterclockwise to be parallel to the coarse coal powder pipe 32, it can be sent into the coarse coal powder pipe 32 under the combined action of the coarse coal powder flowing behind.

[0048] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A boiler that uses premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides, characterized in that, The system includes a boiler body; one side of the boiler body is connected to a combustion-supporting pipe, and the other side is connected to a flue gas pipe; the end of the flue gas pipe near the boiler body is equipped with an inhibition device that can ignite pulverized coal and suppress the generation of nitrogen oxides; the flue gas pipe near the inlet end is equipped with a stirring device for improving the mixing degree of pulverized coal and oxygen; the stirring device includes a horizontal plate radially disposed on the inner wall of the flue gas pipe; a first motor is vertically disposed on the horizontal plate; a gas supply pipe is connected to the power end of the first motor; several stirring cylinders are evenly distributed along the circumferential sidewalls along the length of the gas supply pipe; each stirring cylinder is connected to the gas supply pipe; a support plate is vertically connected to the inner wall of the stirring cylinder at the end away from the gas supply pipe; a turntable is rotatably connected to the support plate via a second motor; a rotating shaft perpendicular to the turntable is disposed on the turntable at a position away from the center; a through hole is opened on the inner wall of the stirring cylinder at the end away from the gas supply pipe; a sliding rod is slidably connected in the through hole; a push plate is connected to the end of the sliding rod away from the gas supply pipe, and a connecting rod is rotatably connected to the other end; the free end of the connecting rod is rotatably connected to the rotating shaft.

2. A boiler that uses premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides according to claim 1, characterized in that: One side of the flue gas pipe is provided with a gas supply device for supplying oxygen to the gas supply pipe; each stirring drum is provided with an intermittent jet device; the intermittent jet device includes a slide tube slidably connected inside the stirring drum; the tube wall of the slide tube near the inner wall of the flue gas pipe is connected to the tube wall of the stirring drum by several springs; several enlarged holes are opened on the circumferential side wall of the slide tube; several spray holes are opened on the circumferential side wall of the stirring drum; when the slide tube compresses the spring, each enlarged hole can communicate with the corresponding spray hole.

3. A boiler using premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides according to claim 2, characterized in that: The gas pipeline has several radially arranged fixing plates evenly connected to its circumferential sidewalls near the first motor. A coal scraping device is provided at the end of the fixed plate away from the first motor; the coal scraping device includes a chute and a strip groove opened in the fixed plate; one side of the strip groove is connected to the chute, and the other side passes through the fixed plate; a slider is slidably connected in the chute through a first tension spring; a third motor located in the strip groove is connected to the slider; a coal scraping rod is coaxially connected to the power end of the third motor; several scraping grooves are evenly opened on the circumferential side wall of the coal scraping rod; a scraper is slidably connected in each scraping groove through a second tension spring; a button for controlling the rotation of the third motor is provided on the side wall of the chute away from the gas pipeline.

4. A boiler using premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides according to claim 3, characterized in that: The gas delivery device includes an oxygen tank located on one side of the flue gas pipe; one end of the horizontal plate passes through the flue gas pipe and has an air inlet; the oxygen tank is connected to the air inlet end of the air inlet; the first motor is connected to the gas delivery pipe via a rotary joint; the air outlet end of the air inlet and the inlet end of the rotary joint are connected via a gas delivery pipe; the outlet end of the rotary joint is connected to the gas delivery pipe.

5. A boiler using premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides according to claim 4, characterized in that: The flue gas pipe is inverted L-shaped; the inlet end of the flue gas pipe has an enlarged section; the outlet end of the flue gas pipe is connected to a light pulverized coal pipe and a coarse pulverized coal pipe, which are respectively connected to the boiler body; the intersection of the light pulverized coal pipe and the coarse pulverized coal pipe is rounded; the pipe wall of the light pulverized coal pipe away from the flue gas pipe has a constricted section; the suppression device is located between the coarse pulverized coal pipe and the constricted section.

6. A boiler using premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides according to claim 5, characterized in that: The suppression device includes a connecting pipe and a coarse ignition pipe installed inside the coarse pulverized coal pipe; the connecting pipe is connected to the coarse ignition pipe; an ignition nozzle is provided on the side wall of the connecting pipe; the connecting pipe is connected to a fuel oil pipe; the fuel oil pipe is connected to a fuel oil tank located on one side of the flue gas pipe; control valves are provided at the end of the fuel oil pipe connected to the connecting pipe and at the ignition nozzle.

7. A boiler using premixed flue gas and oxygen to aid combustion and reduce nitrogen oxides according to claim 6, characterized in that: A fourth motor is installed at the junction of the flue gas pipe, the light pulverized coal pipe, and the coarse pulverized coal pipe; the power end of the fourth motor is coaxially connected to a connecting shaft; three filter plates are evenly distributed around the connecting shaft; and several filter holes are opened on the filter plates.

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