Anthracite combustion flame boiler device

Abstract

The invention relates to the field of flame boiler devices, and discloses an anthracite combustion flame boiler device which comprises a hearth and an upper hearth communicated with the hearth, the hearth comprises an upper combustion chamber, a middle combustion chamber and a lower combustion chamber which are sequentially connected, over-fire air inlets are symmetrically formed in the outer wall of the upper hearth, and the over-fire air inlets are connected with an over-fire air bellow; nozzles are symmetrically formed in the outer wall of the upper combustion chamber, the included angle between the incident angle of each nozzle and the vertical direction is 12-17 degrees, a plurality of exhaust air inlets are symmetrically formed in the outer wall of the middle combustion chamber, a plurality of graded air inlets are symmetrically formed in the outer wall of the middle combustion chamber, the graded air inlets are connected with graded air bellows, and the excess air coefficient in the hearth is 1.2. The furnace temperature field can be maintained to be uniform and stable, local overtemperature or low temperature is avoided, grading air and over-fire air are matched to effectively prevent the water cooling wall and the heating surface of the upper furnace from slagging, the slag removal maintenance frequency is reduced, and the service life of equipment is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flame boiler device, and particularly relates to a bituminous coal combustion flame boiler device. BACKGROUND

[0002] W flame boiler is a kind of power station boiler mainly used for burning bituminous coal, lean coal and other low volatile coal, and the boiler burner is one of the key equipment of the combustion device, which can ensure that the air for coal combustion can be fully mixed at a certain speed when entering the boiler, and can be ignited and stably combusted in time. The prior art discloses a concentrated type double air adjusting cyclone burner and combustion method (publication number: CN104390214A), which comprises a deflector pipe, the deflector pipe is connected with an inlet elbow, the inlet elbow is connected with a concentrator, the concentrator is connected with a combustion cylinder, the combustion cylinder is connected with an air adjusting device, the air adjusting device is provided with an air adjusting sleeve, the inlet elbow is provided with a tongue-shaped plate, the concentrator is provided with a waste gas pipe, and the tongue-shaped plate is connected with the waste gas pipe; the burner of the prior art adopts a staged air supply mode, which is beneficial to the ignition and stable combustion of the coal powder, enhances the adaptability of the burner to the medium change, and is also beneficial to controlling the generation of nitrogen oxides in the flame, but due to the influence of market factors, the quality of the coal into the furnace (high ash, high sulfur and low calorific value coal) deviates from the designed coal, power plants gradually begin to adopt mixed coal combustion technology to reduce the production cost of the power plant, which leads to the problems of high NO X emission, low combustion efficiency, slagging and partial burning of the W flame boiler in the running process, and therefore, the present application provides a bituminous coal combustion flame boiler device to solve the above problems. SUMMARY

[0003] The present application aims to provide a bituminous coal combustion flame boiler device to solve the problems of high NO X emission, low combustion efficiency, slagging and partial burning of the W flame boiler in the running process caused by the power plant adopting mixed coal combustion technology to reduce the production cost of the power plant.

[0004] To achieve the above object, the present application adopts the following technical scheme: a smokeless coal combustion flame boiler device, comprising a furnace and an upper furnace connected with the furnace, the furnace comprises sequentially connected upper combustion chamber, middle combustion chamber and lower combustion chamber, and the upper combustion chamber is connected with the upper furnace, the cross sections of the upper combustion chamber and the lower combustion chamber are all set as isosceles trapezoid, the included angle between the waist of the upper combustion chamber and the inner wall of the middle combustion chamber is set as 110°-120°, and the included angle between the waist of the lower combustion chamber and the inner wall of the middle combustion chamber is set as 140°-150°, the outer wall of the upper furnace is symmetrically provided with an overfire air inlet, the overfire air inlet is connected with an overfire air box, the outer wall of the upper combustion chamber is symmetrically provided with a plurality of nozzles capable of being connected with the deflector pipe of the burner, and the included angle between the incident angle of the nozzle and the vertical direction is set as 12°-17°, the outer wall of the middle combustion chamber is symmetrically provided with a plurality of flue gas air inlets, the flue gas pipe of the burner is capable of being connected with the flue gas air inlet, the outer wall of the middle combustion chamber is symmetrically provided with a plurality of staged air inlets, the staged air inlets are connected with a staged air box, and the excess air coefficient in the furnace is set as 1.2.

[0005] The beneficial effects of the present scheme are as follows: the upper combustion chamber and the lower combustion chamber both adopt isosceles trapezoidal cross section, which can guide the flue gas to form a slow-flowing turning channel, avoid the coal powder gas flow from washing the furnace wall too fast or directly discharging, prolong the residence time of the coal powder in the furnace, set the included angle between the incident angle of the nozzle and the vertical direction as 12°-17°, avoid the coal powder gas flow from being insufficient due to too small incident angle, the flame from being concentrated in the upper furnace, and the high temperature area from being dispersed; meanwhile, avoid the gas flow from being deflected due to too large incident angle, form a backflow vacuum area, the coal powder from being insufficiently mixed with the high temperature flue gas, and ensure the coal powder gas flow injected from the front and rear arches to accurately converge in the middle combustion chamber, form a symmetrical and stable W-shaped flame, and concentrate the high temperature area in the middle part of the furnace, which can both strengthen the coal powder ignition and avoid the flame from washing the water-cooled wall, further improve the burnout efficiency, the flue gas air inlet is connected with the flue gas pipe of the burner, 10%-15% of the separated coal powder (containing 50% of the primary air) is injected into the middle combustion chamber, avoid the high concentration coal powder from mixing with oxygen too early, reduce the NOx generated in the initial stage of combustion, the staged air box supplements oxygen through the staged air inlet in the middle stage of coal powder combustion, at this time, the coal powder has completed ignition, and appropriate oxygen supplement can avoid "oxygen deficiency extinction", and avoid the NOx surge caused by high oxygen environment in the initial stage of combustion, the overfire air box supplements a small amount of oxygen through the overfire air inlet in the upper furnace, ensures the fully burnout of the unburned fine coal powder, and does not increase the NOx in the later stage of combustion. X X X ​​The generated amount, the excess air coefficient is too low, will cause local hypoxia lead to incomplete combustion of pulverized coal, unburned coal accumulation in the furnace wall, easy to form slag, and the excess air coefficient is too high, will lead to excess air cooling furnace temperature, lead to coal powder ignition delay, flame center up, the upper furnace heating surface over temperature; and the excess air coefficient is set to 1.2, can maintain the uniform and stable furnace temperature field, avoid local overheating or low temperature, with the classification of air and burn-out air can effectively prevent water-cooled wall and the upper furnace heating surface slagging, reduce the slagging maintenance frequency, prolong the service life of the equipment.

[0006] Preferably, as an improvement, the angle between the incident angle of each exhaust gas air inlet and the vertical direction is 60°.

[0007] The beneficial effect is that the exhaust gas air inlet is arranged on the outer wall of the middle combustion chamber, and the middle combustion chamber is the turning area of the W-shaped flame, that is, the main pulverized coal gas flow transported by the symmetrically arranged nozzles extends downward and then turns upward to form a high-temperature smoke backflow area. If the incident angle of the exhaust gas air inlet is too large, the exhaust gas air will directly impact the main pulverized coal gas flow, destroying the symmetry of the W-shaped flame. If the incident angle of the exhaust gas air inlet is too small, the exhaust gas air will quickly sink to the lower combustion chamber and not mix with the main pulverized coal gas flow sufficiently, causing local coal accumulation. By setting the incident angle of the exhaust gas air inlet to 60°, the exhaust gas air can flow along the inner wall of the middle combustion chamber and cut in, forming a staggered layer with the main pulverized coal gas flow, avoiding airflow interference and ensuring uniform dispersion of low-concentration coal powder in the high-temperature backflow area.

[0008] Preferably, as an improvement, the angle between the incident angle of each classification air inlet and the vertical direction is 65°.

[0009] The beneficial effect is that the incident angle of 65° allows the classification air to flow slowly along the inner wall of the middle combustion chamber, supplementing oxygen before the main pulverized coal gas flow ignites and before entering the burn-out stage, avoiding a high-oxygen environment in the early stage of combustion and providing support for continuous combustion of coal powder.

[0010] Preferably, as an improvement, the incident angle of the burn-out air inlet is perpendicular to the outer wall of the upper furnace.

[0011] Preferably, as an improvement, the opening of the inner air adjusting blade of the burner is set to 100%, and the opening of the outer air adjusting blade of the burner is set to 50%.

[0012] The beneficial effects are that the inner adjusting air blade controls the rotational flow intensity and air volume of the inner secondary air, the inner adjusting air blade is at 100% opening degree, the inner secondary air has sufficient air volume and moderate rotational flow intensity, can efficiently entrain the high-temperature flue gas in the furnace, directly acts on the high-concentration pulverized coal gas flow at the outlet of the burner, rapidly increases the temperature of the pulverized coal gas flow to the ignition point, avoids the problems of ignition delay and easy to extinguish of low-volatile anthracite, and the core role of the outer secondary air is to supplement oxygen for the pulverized coal in the middle and later stages of combustion, the outer adjusting air blade is at 50% opening degree, the outer secondary air has moderate air volume, can slowly and uniformly mix into the core area of the flame, avoids that the excessive outer secondary air blows away the flame due to too strong air flow, or that the local oxygen deficiency is not fully combusted due to insufficient air volume.

[0013] Preferably, as an improvement, eight groups of combustion assemblies are further included, each group of combustion assemblies includes two burners, each group of combustion assemblies is symmetrically arranged at two ends of the upper combustion chamber close to the injection ports, and the deflector pipes of the burners are respectively connected with the corresponding injection ports, the secondary air of the four groups of burners on the same side rotates in the clockwise direction, and the secondary air of the four groups of burners on the other side rotates in the counterclockwise direction. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a structural schematic view of the flame boiler device of the embodiment of the present application; Figure 2 It is a temperature field of the flame boiler device of the embodiment of the present application under different opening degrees of the inner adjusting air blade; Figure 3 It is a temperature field of the flame boiler device of the embodiment of the present application under different opening degrees of the outer adjusting air blade; Figure 4 It is a NO concentration distribution nephogram of the flame boiler of the embodiment of the present application under different opening degrees of the outer adjusting air blade. DETAILED DESCRIPTION

[0015] The following is further described in detail through specific embodiments: The reference signs in the drawings of the specification include: furnace 1, upper furnace 2, upper combustion chamber 3, middle combustion chamber 4, lower combustion chamber 5, overfire air inlet 6, injection port 7, spent gas air inlet 8, and staged air inlet 9.

[0016] EMBODIMENT The embodiment is basically as shown in the accompanying drawings, for example, Figures 1-4 Figure 1 ​The illustrated anthracite combustion flame boiler device comprises a furnace 1 and an upper furnace 2 connected with the furnace 1, the furnace 1 comprises sequentially connected upper combustion chamber 3, middle combustion chamber 4 and lower combustion chamber 5, and the upper combustion chamber 3 is connected with the upper furnace 2, the cross sections of the upper combustion chamber 3 and the lower combustion chamber 5 are all set as isosceles trapezoids, the included angle between the waist of the upper combustion chamber 3 and the inner wall of the middle combustion chamber 4 is set as 110°-120°, and the included angle between the waist of the lower combustion chamber 5 and the inner wall of the middle combustion chamber 4 is set as 140°-150°, in the embodiment, the included angle between the waist of the upper combustion chamber 3 and the inner wall of the middle combustion chamber 4 is set as 115°, and the included angle between the waist of the lower combustion chamber 5 and the inner wall of the middle combustion chamber 4 is set as 145°, a plurality of overfire air inlets 6 are symmetrically and fixedly installed at the left and right ends of the upper furnace 2, and the incident angles of the overfire air inlets 6 are all perpendicular to the outer wall of the upper furnace 2, in the embodiment, the overfire air inlets 6 located at the same end are set as 8, the overfire air inlets 6 are connected with overfire air boxes, the overfire air boxes horizontally deliver overfire air into the upper furnace 2 through the overfire air inlets 6, 8 overfire air inlets 7 are symmetrically and fixedly installed at the left and right ends of the upper combustion chamber 3 and can be connected with the deflection pipes of the burners, and the included angle between the incident angle of the overfire air inlets 7 and the vertical direction is set as 12°-17°, in the embodiment, the included angle between the incident angle of the overfire air inlets 7 and the vertical direction is set as 15°, a plurality of flue gas inlets 8 are symmetrically arranged at the left and right ends of the middle combustion chamber 4, in the embodiment, the flue gas inlets 8 located at the same end are set as 8, and the flue gas pipes of the burners can be connected with the flue gas inlets 8, and the included angle between the incident angle of each flue gas inlet 8 and the vertical direction is set as 60°, a plurality of staged air inlets 9 are symmetrically arranged at the outer wall of the middle combustion chamber 4, in the embodiment, the staged air inlets 9 located at the same end are set as 8, and the included angle between the incident angle of each staged air inlet and the vertical direction is set as 65°, the staged air inlets 9 are connected with staged air boxes, and the staged air boxes deliver staged air into the middle combustion chamber 4 through the staged air inlets 9.

[0017] It also comprises eight groups of combustion assemblies, each group of combustion assembly comprises two burners, the burners are set as concentrated EI-XCL double air adjustment cyclone burners, each group of combustion assembly is symmetrically arranged at the two ends of the upper combustion chamber 3 close to the overfire air inlets 7, the deflection pipes of each burner are respectively connected with the corresponding overfire air inlets 7, the secondary air rotation directions of each group of burners are same, the secondary air of the four groups of burners located at the front side rotates along the clockwise direction, the secondary air of the four groups of burners located at the rear side rotates along the counterclockwise direction, and the corresponding air speeds of the inner air adjustment blades and the outer air adjustment blades of each burner under different opening degrees are shown in the following table:

[0018] As Figure 2The temperature field of the flame boiler under different inner air adjusting blade openings can be directly observed, and when the inner air adjusting blade opening is set to 100%, a strong cyclone effect can be generated, and under this opening, the high-temperature area near the burner nozzle 7 in the furnace 1 is more reasonably distributed, which is conducive to the entrainment of high-temperature flue gas in the furnace 1. For low-volatile anthracite, this can quickly increase the temperature of the pulverized coal gas flow to reach the ignition point, solving the problem of difficult ignition of anthracite.

[0019] As shown in Figure 3 The temperature field of the flame boiler under different outer air adjusting blade openings can be directly observed, and when the outer air adjusting blade opening is 50%, the airflow distribution in the furnace 1 is relatively stable, and flame deflection or airflow turbulence caused by too fast or too slow outer secondary air velocity is avoided, ensuring the stable formation of the W-shaped flame and avoiding combustion instability such as flame shaking and extinguishing, thereby ensuring the stable operation of the flame boiler.

[0020] As shown in Figure 4 The NO concentration distribution cloud diagram of the flame boiler under different outer air adjusting blade openings can be directly observed, and when the outer air adjusting blade opening is 50%, the NO concentration distribution in the furnace 1 is relatively uniform and the overall concentration is relatively low, indicating that when the outer air adjusting blade opening is 50%, the flame core temperature can be stabilized in the optimal combustion temperature range of anthracite, which not only meets the high-temperature environment required for burnout, but also avoids excessive NO caused by local overheating.

[0021] Therefore, in the present embodiment, the opening of the inner air adjusting blade of each burner is set to 100%, the opening of the outer air adjusting blade of each burner is set to 50%, the corresponding inner secondary air velocity is 16.15 m / s, the outer secondary air velocity is 8.07 m / s, and the excess air coefficient in the furnace 1 is set to 1.2.

[0022] The upper and lower combustion chambers 3 and 5 are both in the shape of an isosceles trapezoid, which can guide the flue gas to form a slow-flowing return channel, avoid the pulverized coal gas flow from washing the furnace wall too quickly or being directly discharged, and prolong the residence time of the pulverized coal in the furnace 1. By setting the included angle between the incident angle of the nozzle 7 and the vertical direction to 15°, the pulverized coal gas flow is prevented from being insufficiently downwashed due to a too small incident angle, and the flame is concentrated in the upper furnace 2, and the high-temperature area is dispersed. At the same time, the incident angle is also prevented from being too large to cause airflow deflection and form a backflow vacuum area, and the pulverized coal and high-temperature flue gas are not mixed sufficiently. An angle range of 12°-17° can ensure that the pulverized coal gas flows injected from the front and rear arches accurately converge in the middle combustion chamber 4, forming a symmetrical and stable W-shaped flame, and the high-temperature area is concentrated in the middle of the furnace 1, which not only strengthens the ignition of the pulverized coal, but also avoids the flame from washing the water-cooled wall, further improving the burnout efficiency. The flue gas inlet 8 is connected with the flue gas pipe of the burner, and 10%-15% of the separated pulverized coal is injected into the middle combustion chamber 4, avoiding the early mixing of high-concentration pulverized coal and oxygen, reducing the generation of NO in the initial stage of combustion, and improving the NO concentration distribution in the furnace 1.X The generation, grading wind box through grading wind inlet 9 in the coal powder combustion period of oxygen, at this time the coal powder has completed the ignition, appropriate oxygen can avoid oxygen deficiency and extinguish, at the same time avoid the high oxygen environment of the initial stage of combustion leading to the surge of NO X The generation, grading wind box through grading wind inlet 9 in the coal powder combustion period of oxygen, at this time the coal powder has completed the ignition, appropriate oxygen can avoid oxygen deficiency and extinguish, at the same time avoid the high oxygen environment of the initial stage of combustion leading to the surge of NO X The generation, grading wind box through grading wind inlet 9 in the coal powder combustion period of oxygen, at this time the coal powder has completed the ignition, appropriate oxygen can avoid oxygen deficiency and extinguish, at the same time avoid the high oxygen environment of the initial stage of combustion leading to the surge of NO

[0023] The specific implementation process is as follows: The three mine points of Southwest Mining, Jikai Noda Xing'an, Aneng are mixed according to the mass ratio of 1:1:1 to form mixed coal, and the calorific value is about 3537kcal / kg. The mixed coal has high combustion efficiency, meets the needs of the power plant under the current working condition, and achieves the purpose of using low-quality coal. After the coal blending is finished, the mixed coal is sent to the mill at a mass flow rate of 90.7t / h, and the excess air coefficient is kept at 1.2. The total air quantity is adjusted to 1031km 3 / h by the air feeder. The burnout air box sends the burnout air into the upper furnace 2 through the burnout air inlet 6. The exhaust air box sends the exhaust air into the middle combustion chamber 4 at an incident angle of 60° through the exhaust air inlet 8. The grading air box sends the grading air into the middle combustion chamber 4 at an incident angle of 65° through the grading air inlet 9. The burner enters the furnace 1 through the nozzle 7 at an incident angle of 15°. Then, the total air quantity of the inner and outer air adjusting channels of the burner remains unchanged, the opening degree of the inner air adjusting blade of the burner is set to 100%, and the opening degree of the outer air adjusting blade of the burner is set to 50% while the air quantity of the burnout air inlet 6, the exhaust air inlet 8, the grading air inlet 9 and the nozzle 7 remains unchanged.

[0024] The above-mentioned are only embodiments of the present application, and common technical solutions and / or common knowledge of the scheme are not described in detail. It should be pointed out that, for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, and these will not affect the effect and practicality of the patent. The protection scope claimed in the present application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A smokeless coal combustion flame boiler apparatus, characterized by: The furnace chamber comprises sequentially connected upper combustion chamber, middle combustion chamber and lower combustion chamber, and the upper combustion chamber is communicated with the upper furnace chamber, the cross sections of the upper combustion chamber and the lower combustion chamber are all set as isosceles trapezoid, the included angle between the waist of the upper combustion chamber and the inner wall of the middle combustion chamber is set as 110°-120°, the included angle between the waist of the lower combustion chamber and the inner wall of the middle combustion chamber is set as 140°-150°, the outer wall of the upper furnace chamber is symmetrically provided with the overfire air inlets, the overfire air inlets are connected with overfire air boxes, the outer wall of the upper combustion chamber is symmetrically provided with a plurality of nozzles capable of being connected with the deflection pipes of the burners, and the included angle between the incident angle of the nozzles and the vertical direction is set as 12°-17°, the outer wall of the middle combustion chamber is symmetrically provided with a plurality of flue gas inlets, the flue gas pipes of the burners are capable of being connected with the flue gas inlets, the outer wall of the middle combustion chamber is symmetrically provided with a plurality of staged air inlets, the staged air inlets are connected with staged air boxes, and the excess air coefficient in the furnace chamber is set as 1.

2.

2. A bituminous coal fired flame boiler apparatus as claimed in claim 1, wherein: The included angle between the incident angle of each flue gas inlet and the vertical direction is all set as 60°.

3. A bituminous coal fired flame boiler apparatus as claimed in claim 2 wherein: The included angle between the incident angle of each staged air inlet and the vertical direction is all set as 65°.

4. A bituminous coal fired flame boiler apparatus as claimed in claim 3 wherein: The incident angle of the overfire air inlet is perpendicular to the outer wall of the upper furnace chamber.

5. A bituminous coal fired flame boiler apparatus as claimed in claim 4 wherein: The opening of the inner air adjusting blade of the burner is set as 100%, and the opening of the outer air adjusting blade of the burner is set as 50%.

6. A bituminous coal fired flame boiler apparatus as claimed in claim 5 wherein: It also comprises eight groups of combustion assemblies, each group of combustion assemblies comprises two burners, each group of combustion assemblies is symmetrically arranged at the two ends of the upper combustion chamber close to the nozzles, the deflection pipes of the burners are respectively connected with the corresponding nozzles, the rotation directions of the secondary air of each group of burners are the same, the secondary air of the four groups of burners located at the same side rotates in the clockwise direction, and the secondary air of the other four groups of burners rotates in the counterclockwise direction.

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