Anti-coking furnace of counter-swirling combustion boiler
By tilting the burner nozzle, the flame trajectory is tilted, the combustion temperature and particulate impact are reduced, and the problem of easy coking in the furnace when burning Jungdong Coal is solved, achieving a safe and environmentally friendly combustion effect.
Patent Information
- Application Number
- CN202421485151.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2025-04-04
- Estimated Expiration
- 2034-06-26
AI Technical Summary
In the prior art, burning Jungdong coal is likely to cause coking in the furnace, forming a safety hazard for boiler combustion. In order to alleviate the coking problem, kaolin needs to be doped, resulting in environmental pollution.
By tilting the burner nozzle, the flame track is tilted upward or downward, pulling the flame to reduce the combustion temperature, allowing the particles to float up in an orderly manner, reducing impact and bonding between particles, thereby preventing the furnace from coking.
It effectively prevents the furnace from coking, reduces the formation of low nitrogen oxides, reduces the safety risks of boiler combustion, and avoids environmental pollution caused by doping kaolin.
Smart Images
Figure CN222718187U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a coking prevention technology for a counter-swirl combustion boiler, in particular to an anti-coking furnace of a counter-swirl combustion boiler, and belongs to the technical field of boiler equipment manufacturing. Background Art
[0002] During the combustion of fuel, the generation of nitrogen oxides is part of the combustion reaction: the nitrogen oxides generated by combustion are mainly NO and NO2, collectively referred to as NOx. NOx in the atmosphere will dissolve in water and generate nitric acid rain. Acid rain will bring extensive harm to the environment, cause huge economic losses, and easily endanger human health.
[0003] Commonly used low-nitrogen combustion uses about 30% of the total secondary air as burnout air. The volatile matter of the primary air powder sprayed out from the main combustion area is burned out first, and some carbon particles are delayed in combustion due to the restriction of oxygen. The center temperature of the flame in the main combustion area is weakened by the control of the combustion air volume, and the NOx generation is reduced synchronously; due to insufficient oxygen, the NOx generation is reduced synchronously again. This low-nitrogen combustion technology has been widely used and recognized. However, due to the reduction in air volume, some fuels are delayed in combustion, and the molten carbon particles are in a state of combustion shock in the closed furnace space, and collide disorderly, resulting in the following problems.
[0004] First of all, the characteristics of the counter-swirl burner are independent ignition, staged combustion, narrow flames of wind-wrapped coal, and parallel non-interference. However, the internal and external secondary air of each burner is greatly reduced, the wind-wrapped coal is weakened, and the volatile matter of the primary air powder is burned first, and some unburned carbon particles are shocked by combustion. The narrow shape of the concentrated primary air powder is even narrower. In the high-temperature furnace, it directly collides with the same concentrated primary air powder coming horizontally from the opposite side, and the same molten unburned carbon particles collide, which is easy to collide and bond. These molten particles continue to collide, bond and grow. Because the raw coal contains different minerals, lignite and sub-bituminous coal have high calcium content, and the particles become coarse and hard after bonding. In particular, Zhundong coal contains high alkali metal ash content and high viscosity, which can easily cause slagging and coking in the furnace, forming a safety hazard for boiler combustion.
[0005] Secondly, due to the reduction of secondary air, the narrow flame of the counter-swirl is longer, and the dense unburned carbon particles in the flame are in a state of combustion shock, but they appear sticky and viscous. Some boilers that did not coke originally also coke. Especially Xinjiang Zhundong coal, which contains high content of alkali metals such as potassium, sodium, magnesium, and iron, is volatile, and has high viscosity after combustion. They collide and stick to each other like a snowball, and large particles stick to the tube wall when they hit it. Coking is a major hidden danger to boiler combustion safety.
[0006] Then, due to deep oxygen-deficient combustion, the strong unburned flame flue gas contains a large amount of CO, which can easily cause high-temperature corrosion and oxidation in the high-temperature environment flame, especially when the coking part of the furnace is unevenly heated, or the water-cooled wall tube is thinned by erosion, and then encounters high-temperature corrosion, causing the water-cooled wall tube peeling and bursting safety hazards.
[0007] Finally, in the process of burning Zhundong coal in the existing technology, in order to alleviate the coking in the furnace and protect the safety of boiler equipment, a certain proportion of kaolin is burned, making the composition of the flue gas emitted by the boiler combustion more complex. This is because kaolin may produce volatile organic compounds (VOCs) and other combustible pollutants during combustion. These wastes pollute the soil, air, and water sources, and pose a more serious threat to the environment and human health.
[0008] Therefore, there is an urgent need for a device that does not require doping with other raw materials, can effectively prevent coking in the furnace and can ensure low-nitrogen combustion. Utility Model Content
[0009] The utility model provides a novel anti-coking furnace of a counter-swirl combustion boiler, which can pull the flame to reduce the combustion temperature and make particles float in an orderly manner by tilting the burner nozzle, so as to solve the technical problem of easy coking of the furnace in the prior art.
[0010] The anti-coking furnace of the counter-swirl combustion boiler of the utility model embodiment comprises: a furnace body, a plurality of groups of overburned air burners and a plurality of groups of burners; the furnace body has a front wall and a rear wall corresponding to each other; each group of the overburned air burners is divided into two, and are arranged on the front wall and the rear wall corresponding to each other;
[0011] A plurality of groups of burners are located below the overburnt air burners; each group of burners is divided into two and are arranged on the front wall and the rear wall corresponding to each other;
[0012] In each group of burners, each burner has a nozzle, which is arranged obliquely; and the injection trajectories of the two nozzles in each group of burners are parallel to each other.
[0013] As described above, the anti-coking furnace of the counter-swirl combustion boiler, wherein the inclination angle of the nozzle is 5 to 20 degrees.
[0014] The anti-coking furnace of the counter-swirl combustion boiler as described above, wherein a horizontal flue is arranged above the furnace body, and a flame folding angle is formed between the rear wall and the horizontal flue;
[0015] The nozzles of the burners on the front wall are all inclined downward, and the nozzles of the burners on the rear wall are all inclined upward.
[0016] The anti-coking furnace of the opposed swirl combustion boiler as described above, wherein each of the burners comprises: a wind box; both ends of the wind box are air inlets; at least three nozzles are arranged on one side of the wind box, wherein the nozzle close to the air inlet is the end nozzle; two air guide plates are arranged in the wind box, and the two air guide plates are symmetrically distributed; the air guide plate is located between the end nozzle and the other nozzles.
[0017] The anti-coking furnace of the opposed swirl combustion boiler as described above, wherein each of the burnout air burners comprises: a burnout air wind box; both ends of the burnout air wind box are burnout air inlets; at least three burnout air nozzles are arranged on one side of the burnout air wind box, wherein the nozzle close to the burnout air inlet is the end burnout air nozzle; two burnout air guide plates are arranged in the burnout air wind box, and the two burnout air guide plates are symmetrically distributed; the burnout air guide plate is located between the end burnout air nozzle and the other burnout air nozzles.
[0018] As described above, the anti-coking furnace of the counter-swirl combustion boiler, wherein the air guide plate is arranged obliquely; one end of the air guide plate is fixed to the inner wall of the wind box, and the other end faces the air inlet.
[0019] As described above, the anti-coking furnace of the counter-swirl combustion boiler, wherein the burnout air guide plate is arranged obliquely; one end of the burnout air guide plate is fixed to the inner wall of the burnout air wind box, and the other end faces the burnout air inlet.
[0020] As described above, the anti-coking furnace of the counter-swirl combustion boiler, wherein the inclination angle of the nozzle is 8 to 15 degrees.
[0021] In the embodiment of the utility model, the burner flame trajectory is tilted upward or downward through the nozzle, and the parallel narrow flame channel is widened, so that the unburned carbon particles can float and extend more orderly and unobstructed. At the same time, the parallel elongated flame path reduces the center temperature of the flame, which not only maintains the generation of low nitrogen oxides, but also greatly reduces the coking of the furnace caused by the collision and adhesion between particles. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a side section schematic diagram of the anti-coking furnace of the counter-swirl combustion boiler according to an embodiment of the utility model;
[0023] Figure 2 This is a side structural diagram of the anti-coking furnace of the counter-swirl combustion boiler according to an embodiment of the utility model. DETAILED DESCRIPTION
[0024] The anti-coking furnace and method of the counter-swirl combustion boiler described in the utility model can be made of the following materials and components, but are not limited to the following materials and components, such as: burner, wind shield, bellows, furnace, burnout air bellows, burnout air burner, etc.
[0025] like Figure 1 The figure shows a side cross-sectional schematic diagram of the anti-coking furnace of the counter-swirl combustion boiler according to the embodiment of the utility model; Figure 2 .
[0026] The anti-coking furnace of the opposed swirl combustion boiler of this embodiment comprises: a chamber body 1, a plurality of groups of burnt air burners 3 and a plurality of groups of burners 2; the chamber body 1 has a front wall 11 and a rear wall 12 corresponding to each other; each group of the burnt air burners 3 is divided into two, and are arranged correspondingly on the front wall 11 and the rear wall 12; the two burnt air burners 3 of each group are on the same horizontal plane and correspond to each other.
[0027] A plurality of groups of burners 2 are located below the overburnt air burners 3; each group of burners 2 is divided into two and are arranged correspondingly on the front wall 11 and the rear wall 12; the two burners 2 of each group are on the same horizontal plane and correspond to each other.
[0028] In each group of the burners 2, each burner 2 has a nozzle 20 (there may be multiple nozzles), and the nozzles 20 are arranged obliquely; the injection trajectories of the two nozzles 20 in each group of the burners 2 are parallel to each other. Figure 1 As shown, in each group of burners 2, the nozzles 20 on the left are tilted downward, and the nozzles on the right are tilted upward, and the injection trajectories of the two are parallel to each other.
[0029] Generally, the nozzle has an inclination angle of 5 to 20 degrees. Preferably, the nozzle has an inclination angle of 8 to 15 degrees. The optimal angle is 9 to 11 degrees.
[0030] In the embodiment of the utility model, the burner flame trajectory is tilted upward through the nozzle, and the parallel narrow flame channel is widened, so that the unburned carbon particles can float and extend more orderly and unobstructed. At the same time, the flame path is parallel and elongated to make the flame temperature low, which not only maintains the low nitrogen oxide generation, but also can greatly reduce the coking of the furnace.
[0031] The utility model retains the counter-swirling combustion characteristics and changes the horizontal counter-swirling combustion in the prior art into parallel wide-width counter-swirling combustion. That is, the burner nozzle is tilted downward or upward at an angle to weaken the trend of the front horizontal counter-swirling flame, and most of the unburned molten shock combustion carbon particles extend and float along the narrow flame trajectory, reducing the turbulence, impact and adhesion in the furnace.
[0032] The utility model changes the horizontal counter-attack concentrated flames on the same layer in the prior art into upper and lower parallel counter-attack diluted flames, reducing the collision and adhesion between particles ejected from the front burner. The parallel wide counter-attack flames can greatly reduce the collision and adhesion between shock combustion carbon particles, and smoothly pass through to the burnout area for combustion and burnout.
[0033] In the anti-coking furnace of the opposed swirl combustion boiler of this embodiment, a horizontal flue 10 is arranged above the chamber body 1, and a flame folding angle 13 is provided between the rear wall 12 and the horizontal flue 10; in the upper part of the rear wall of the boiler combustion chamber, there is a triangular protrusion extending into the furnace chamber, and the protrusion is called the flame folding angle. The functions of the flame folding angle are mainly: (1) to increase the length of the horizontal flue; (2) to improve the heat transfer effect of the screen superheater; (3) to increase the fullness of the flue gas in the furnace so that the distribution of the flue gas along the height direction of the combustion chamber tends to be uniform.
[0034] The nozzles of the burners 2 on the front wall 11 are all inclined downward, and the nozzles of the burners 2 on the rear wall 12 are all inclined upward.
[0035] Because the furnace space of the front wall 11 is relatively higher than the space of the rear wall 12, such a narrow and long flame inclination is more suitable for flame distribution.
[0036] like Figure 2 As shown; the anti-coking furnace of the opposed swirl combustion boiler of this embodiment, each of the burners 2 comprises: a wind box 21; both ends of the wind box 21 are air inlets 22; at least three nozzles 20 are arranged on one side of the wind box 21, wherein the nozzle close to the air inlet 22 is the end nozzle; two air guide plates 23 are arranged in the wind box 21, and the two air guide plates 23 are symmetrically distributed; the air guide plate 23 is located between the end nozzle and the other nozzles.
[0037] The air guide plate 23 can ensure that the circumference of the water-cooled wall nozzles on both sides of the wind box 21 is full of air intake, thereby preventing unburned particles from coking on the water-cooled walls on both sides of the wind box during the combustion process. The design of the air guide plate 23 ensures that the circumference of the burners on both sides of the wall is full, strengthens the wind-coated coal effect of the secondary air at the end nozzle, and prevents the primary air from blowing the coal powder particles against the water-cooled wall tube wall, or the molten unburned particles from colliding and bonding with the tube wall. During the combustion process, some coarse particles are very hard after carbon bonding, causing scouring and thinning of the side wall water-cooled wall tube wall. The design of this embodiment fully avoids this situation.
[0038] Similarly, each of the burnout air burners 3 includes: a burnout air wind box 31; both ends of the burnout air wind box 31 are burnout air inlets 32; at least three burnout air nozzles are arranged on one side of the burnout air wind box 31, wherein the nozzle close to the burnout air inlet 32 is the end burnout air nozzle; two burnout air guide plates 33 are arranged in the burnout air wind box 31, and the two burnout air guide plates 33 are symmetrically distributed; the burnout air guide plate 33 is located between the end burnout air nozzle and the other burnout air nozzles.
[0039] The design of this area is the same as the combustion area to avoid coking of particles on the water-cooled wall here.
[0040] Generally, the air guide plate 23 is arranged at an angle; one end of the air guide plate 23 is fixed to the inner wall of the wind box 21 , and the other end faces the air inlet 22 .
[0041] Similarly, the burnt air guide plate 33 is tilted; one end of the burnt air guide plate 33 is fixed to the inner wall of the burnt air wind box 31 , and the other end faces the burnt air inlet 32 .
[0042] The present embodiment also provides a method for preventing coking of a counter-swirl combustion boiler, which adopts the counter-swirl combustion boiler anti-coking furnace of the above embodiment; the exhaust volume and wind pressure of the end nozzle are greater than or equal to the exhaust volume and wind pressure of other nozzles; the exhaust volume and wind pressure of the end burnout air nozzle are greater than or equal to the exhaust volume and wind pressure of other burnout air nozzles.
[0043] The high-pressure and high-flow design of the end nozzle and the end burnout air nozzle ensures full circumferential air intake to the burners on both sides of the wall, strengthens the wind-enveloping coal effect of the secondary air of the end nozzle (the coal powder is completely wrapped by the secondary air to avoid contact with the inner wall of the furnace during the combustion process of the coal powder), and prevents the primary air from carrying coal powder particles to blow against the water-cooled wall tube wall, or the molten unburned particles from colliding and bonding with the tube wall.
[0044] Furthermore, in each of the burners, the nozzle close to the left air inlet is the left nozzle, and the nozzle close to the right air inlet is the right nozzle; the swirl when the left nozzle sprays is in a clockwise direction, and the swirl when the right nozzle sprays is in a counterclockwise direction; the plane where the swirl is located here is perpendicular to the axis direction of the injection trajectory.
[0045] In each of the burnout air burners, the burnout air nozzle close to the left burnout air inlet is the left burnout air nozzle, and the burnout air nozzle close to the right burnout air inlet is the right burnout air nozzle; the swirl flow when the left burnout air nozzle sprays is in a clockwise direction, and the swirl flow when the right burnout air nozzle sprays is in a counterclockwise direction.
[0046] This design is conducive to the coal powder particles to float upward along the water-cooled wall for combustion. The swirl direction of the rear wall burner nozzle during combustion is the same as that of the front wall, and the upward swirl trend on both sides is also maintained, which maximizes the smooth and orderly floating combustion of the air and powder airflow in the furnace.
[0047] In addition, the anti-coking furnace of the utility model of the counter-swirl combustion boiler has low implementation costs, exquisite layout, compact structural design, is not easy to coke, does not require additional kaolin doping, is easy to maintain, is suitable for various swirl counter-combustion boilers, and is particularly suitable for the combustion of Zhundong coal.
[0048] The serial numbers of the above-mentioned embodiments of the utility model are only for description and do not represent the advantages and disadvantages of the embodiments. Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of some deformations plus the necessary general technology superposition; of course, it can also be implemented by simplifying some important technical features. Based on this understanding, the technical solution of the utility model is essentially or the part that contributes to the prior art is: the overall structure and connection method, and the structure described in each embodiment of the utility model.
[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.
Claims
1. A counter-swirl combustion boiler anti-coking furnace, characterized in that: include: A chamber body, a plurality of groups of overburned air burners and a plurality of groups of burners; the chamber body has a front wall and a rear wall corresponding to each other; each group of overburned air burners is divided into two, and are arranged on the front wall and the rear wall corresponding to each other; A plurality of groups of burners are located below the overburnt air burners; each group of burners is divided into two and are arranged on the front wall and the rear wall corresponding to each other; In each group of burners, each burner has a nozzle, which is arranged obliquely; and the injection trajectories of the two nozzles in each group of burners are parallel to each other.
2. The anti-coking furnace of the opposed swirl combustion boiler according to claim 1 is characterized in that: The inclination angle of the nozzle is 5 to 20 degrees.
3. The anti-coking furnace of the opposed swirl combustion boiler according to claim 2 is characterized in that: A horizontal flue is arranged above the chamber body, and a flame folding angle is formed between the rear wall and the horizontal flue; The nozzles of the burners on the front wall are all inclined downward, and the nozzles of the burners on the rear wall are all inclined upward.
4. The anti-coking furnace of the opposed swirl combustion boiler according to any one of claims 1 to 3, characterized in that: Each of the burners comprises: a wind box; both ends of the wind box are air inlets; at least three nozzles are arranged on one side of the wind box, wherein the nozzle close to the air inlet is the end nozzle; two air guide plates are arranged in the wind box, and the two air guide plates are symmetrically distributed; the air guide plate is located between the end nozzle and the other nozzles.
5. The anti-coking furnace of the opposed swirl combustion boiler according to claim 4 is characterized in that: Each of the burnout air burners comprises: a burnout air wind box; both ends of the burnout air wind box are burnout air inlets; at least three burnout air nozzles are arranged on one side of the burnout air wind box, wherein the nozzle close to the burnout air inlet is the end burnout air nozzle; two burnout air guide plates are arranged in the burnout air wind box, and the two burnout air guide plates are symmetrically distributed; the burnout air guide plate is located between the end burnout air nozzle and the other burnout air nozzles.
6. The anti-coking furnace of the counter-swirl combustion boiler according to claim 4 is characterized in that: The air guide plate is arranged obliquely; one end of the air guide plate is fixed to the inner wall of the wind box, and the other end faces the air inlet.
7. The anti-coking furnace of the opposed swirl combustion boiler according to claim 5 is characterized in that: The burnt-out wind guide plate is arranged obliquely; one end of the burnt-out wind guide plate is fixed to the inner wall of the burnt-out wind box, and the other end faces the burnt-out wind inlet.
8. The anti-coking furnace of the opposed swirl combustion boiler according to any one of claims 1 to 3, characterized in that: The inclination angle of the nozzle is 8 to 15 degrees.