CN201259216Y - Pulverized coal burner - Google Patents

Abstract

The utility model discloses a pulverized coal burner, which comprises a decelerating pilot chamber; wherein, at least one jack is arranged on the axial sidewall of the decelerating pilot chamber; and an ignition unit which is used to ignite the pulverized coal passing through the decelerating pilot chamber is plugged in the jack. Under the premise that other conditions are not changed, the heating energy applied on the pulverized coal is in proportion to the heating time, and the heating energy of flames applied on the pulverized coal is increased by a factor each time the gas flow velocity is reduced by a factor. Since the utility model arranges a pilot chamber into the decelerating pilot chamber, that is, the speed of the pulverized coal passing through the pilot chamber is reduced, the pulverized coal can stay in the high-temperature flames for a longer time, so that the heating energy of the flames applied on the pulverized coal can be increased in order to accelerate thermo-chemical conversion to reproduce volatile matters to promote complete combustion and then promote ignition and stable combustion.

Description

a pulverized coal burner

technical field

The utility model relates to a pulverized coal burner.

Background technique

After the pulverized coal is ignited, its combustion process is heating up, water evaporation, pyrolysis volatilization, volatile content burning and co-combustion of volatile content and coke. But for the poorer low-quality coal powder, its volatile content is low, so it is not easy to be ignited.

Existing pulverized coal burners are generally used to ignite pulverized coal with a high volatile content, and in order to improve the favorable conditions for pulverized coal to be ignited, a burner for thick and thin pulverized coal has been produced. For example, the utility model patent of Chinese Patent No. CN200820013109.X discloses a "plasma pulverized coal burner", which consists of a primary combustion chamber, a primary combustion chamber throat, a secondary combustion chamber, and a secondary combustion chamber. Chamber throat, outer sleeve and pulverized coal concentration separation device, a plasma generator is installed in the primary combustion chamber; among them, the middle part of the primary and secondary combustion chambers is equipped with a Venturi tube structure that first converges and then diffuses. The point where it converges to the minimum is the throat of the combustion chamber.

In the above-mentioned plasma pulverized coal burner, the operation process of the pulverized coal is as follows: the primary air passes through the pulverized coal concentration and thinness separation device, and is divided into two airflows, the dense phase powder air and the light phase powder air, and the dense phase powder air flow enters the primary combustion chamber , is ignited by the plasma arc generated by the plasma generator, and is sprayed into the secondary combustion chamber at high speed through the throat of the primary combustion chamber, and the coal powder in the secondary combustion chamber is ignited, and the flame is sprayed into the furnace and light coal The powder air flow and the secondary air meet to continue burning. The light-phase powder air flow enters the annular gap between the primary combustion chamber, the secondary combustion chamber and the outer sleeve, cools the wall surface of the combustion chamber and sprays out from the outlet of the outer sleeve to participate in combustion.

The above-mentioned plasma pulverized coal burner adopts a pulverized coal concentration separation device, so that the plasma arc ignites the dense phase powder air flow, so that the pulverized coal is in a condition that is more conducive to being ignited, but even so, due to the poor quality pulverized coal The volatile matter is lower, and the above-mentioned existing pulverized coal burner still cannot ignite it.

Therefore, it is necessary to provide a novel pulverized coal burner to overcome the above-mentioned defects.

Utility model content

The purpose of the utility model is to provide a pulverized coal burner, which prolongs the stay time of the pulverized coal under the high-temperature plasma flame, and overcomes the defect of insufficient heating time of the pulverized coal caused by the short plasma flame.

The above purpose of the utility model can be achieved by adopting the following technical solutions. A pulverized coal burner is characterized in that: the burner includes a slow-down ignition combustion chamber, and the axial side wall of the slow-down ignition combustion chamber is provided with There is at least one jack, and an ignition device for igniting pulverized coal passing through the reduced-speed ignition combustion chamber is inserted in the jack.

In a preferred embodiment, the deceleration ignition combustion chamber includes a deceleration pipe, and the deceleration pipe is located at the front of the deceleration pipe, and the cross-section from the pulverized coal inlet end to the pulverized coal outlet end is gradually enlarged. , the nozzle of the above-mentioned ignition device is located inside the deceleration tube, and is located at the position where its cross section has been enlarged.

In a preferred embodiment, the deceleration ignition combustion chamber includes a tube wall, the above-mentioned deceleration tube is axially arranged at the central position of the tube wall, and the deceleration tube and the tube wall pass through at least one support plate connect.

In a preferred embodiment, the support plate is arranged in an arc shape.

In a preferred embodiment, the front end of the tube wall protrudes out of the front end of the speed reduction tube in the axial direction, and the tube wall is provided with a diverging portion at its front portion, and the diverging portion extends from The section in the direction from the pulverized coal inlet end to the pulverized coal outlet end is gradually enlarged.

In a preferred embodiment, an eccentric dense-lean separation block is provided on the inner surface of the tube wall and at the axial position between the diverging portion and the deceleration tube.

In a preferred embodiment, at a position between the eccentric dense-lean separation block and the deceleration tube, a concentrated powder guide tube is arranged on the central axis of the tube wall.

In a preferred embodiment, a flame stabilizing ring is provided on the inner wall of the rear end of the deceleration tube.

In a preferred embodiment, a thick-lean separation block is provided on the inner wall at the rear end of the tube wall of the decelerating combustion chamber.

In a preferred embodiment, the burner further includes a mixed combustion chamber, which is connected to the rear end of the reduced-speed ignition combustion chamber.

In a preferred embodiment, a thick-lean separation pipe is arranged axially in the center of the mixed combustion chamber, the diameter of the rear end of the thick-lean separation pipe is larger than the diameter of the above-mentioned speed reduction pipe, and the thick-lean separation pipe passes at least A rib connection.

In a preferred embodiment, the ribs are arranged in an arc shape.

In a preferred embodiment, the burner further includes an enhanced oxygen supply combustion chamber, which is connected to the tail end of the mixing combustion chamber.

In a preferred embodiment, the inlet end of the oxygen supply enhanced combustion chamber is sleeved on the outside of the tail end of the mixing combustion chamber by means of a connecting plate, and a double-layer supplementary air inlet is formed between the two.

Features and advantages of the utility model are:

1. It has the gradual expansion part at the front end of the tube wall and the two-stage deceleration process of the deceleration tube, so that the plasma flame or the micro-oil flame makes the coal powder form a high concentration, high temperature, low speed, less air, and easy to burn in the ignition area. favorable conditions for fire;

2. It makes the air powder concentration and airflow velocity of the system in a working condition that is very conducive to ignition by slowing down the ignition combustion chamber, mixing combustion chamber and oxygen supply enhanced combustion chamber, thereby completing a continuous and stable ignition and combustion process .

Description of drawings

The following drawings are only intended to illustrate and explain the utility model schematically, and do not limit the scope of the utility model. in,

Fig. 1 is the front view schematic diagram of pulverized coal burner of the present utility model;

Fig. 2 is the front view sectional schematic diagram of the pulverized coal burner of the present utility model;

Fig. 3 is the top view sectional schematic diagram of the pulverized coal burner of the present utility model;

Fig. 4 is a schematic sectional view along the line A-A of Fig. 3;

Fig. 5 is a schematic sectional view along the B-B line of Fig. 3;

Fig. 6 is a schematic sectional view along the C-C line of Fig. 3;

Fig. 7 is a schematic cross-sectional view along the D-D line of Fig. 3;

Fig. 8 is a schematic cross-sectional view of the combined state of the hybrid combustion chamber and the oxygen supply enhanced combustion chamber of the present invention;

Fig. 9 is a schematic cross-sectional view along the E-E line of Fig. 8;

FIG. 10 is a schematic cross-sectional view along line F-F of FIG. 8 .

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation of the utility model is now described with reference to the accompanying drawings. Wherein, the same parts adopt the same reference numerals.

Embodiment 1

As shown in Figures 1-3, the utility model provides a pulverized coal burner, which includes a reduced-speed ignition combustion chamber 1, and at least one socket 11 is provided on the axial side wall of the reduced-speed ignition combustion chamber 1, In this embodiment, an insertion hole 11 is provided, and an ignition device is inserted in the insertion hole 11 for igniting the pulverized coal passing through the reduced-speed ignition combustion chamber 1 . Wherein, the ignition device may be a micro-oil gun or a plasma gun or the like.

Since the heating energy of pulverized coal is directly proportional to the heating time under the premise that other conditions remain unchanged, the heating energy of the pulverized coal by the flame will be doubled every time the air velocity is doubled. In the utility model, the ignition combustion chamber is set as a speed-reducing ignition combustion chamber 1, that is, the speed at which pulverized coal passes through the ignition combustion chamber is reduced, so that the time for the pulverized coal to stay under the high-temperature flame can be prolonged, and the flame has a greater impact on the pulverized coal. The heating energy is increased to accelerate the thermochemical conversion and regenerate volatiles to promote complete combustion, which is beneficial to ignition and stable combustion.

In a specific embodiment, the deceleration ignition combustion chamber includes a deceleration tube 12, and the deceleration tube 12 is at the position of its front part 121, and the cross section in the direction from the pulverized coal inlet end to the pulverized coal outlet end is gradually enlarged. , the nozzle of the above-mentioned ignition device is located inside the deceleration pipe 12, and is located at the position where its cross section has been enlarged. That is to say, since the cross section of the front portion of the deceleration tube 12 is gradually enlarged, the velocity of the pulverized coal here is gradually reduced, which is beneficial to the ignition of the pulverized coal.

The deceleration ignition combustion chamber also includes a tube wall 13 , the deceleration tube 12 is axially arranged at the central position of the tube wall 13 , and the deceleration tube 12 and the tube wall 13 are connected by at least one support plate 14 . Among them, the support plate 14 is preferably arc-shaped, because when the high-temperature flame in the combustion chamber is decelerated and ignited, the deceleration tube 12 will be subjected to lateral and longitudinal thermal expansion, and the arc-shaped support plate 14 can use its own Deformation relieves stress.

In a preferred embodiment, the front end of the tube wall 13 protrudes from the front end of the deceleration tube 12 in the axial direction, and the tube wall 13 is provided with a A gradual expansion part 131, the cross section of the gradual expansion part 131 from the pulverized coal inlet end to the pulverized coal outlet end is gradually enlarged.

On the inner surface of the pipe wall 13, and at the axial position between the diverging portion 131 and the deceleration pipe 12, an eccentric thick-lean separation block 15 is provided so that the The pulverized coal is introduced into the central area of the pipe wall 13 through the impact guide of the eccentric thick-lean separation block 15 . And preferably at the position between the eccentric thick-lean separation block 15 and the speed reduction tube 12, a concentrated powder guide pipe 16 is provided on the central axis of the pipe wall 13 to guide the eccentric thick-lean separation block 15. The pulverized coal is guided into the deceleration pipe 12.

The pulverized coal coming from the bend is decelerated by one stage at the diverging portion 131 , and then introduced into the central area of the pipe wall 13 through the impact guide of the eccentric thick-lean separation block 15 . After that, the concentrated powder guide pipe 16 divides the pulverized coal into two streams of pulverized coal and pulverized light coal. The pulverized coal enters the interior of the deceleration tube 12 to participate in combustion, and obtains a two-stage deceleration at the front of the deceleration tube 12. The gas flow rate after the second-stage speed reduction can be designed according to the coal quality characteristics to be 10%-80% of the gas flow rate before the first-stage speed change. The residence time under the flame is increased by 1-5 times, so that the heating energy of the flame on the coal powder is increased by 1-5 times, and then the combustion is promoted, which is beneficial to the ignition. Light coal powder then enters the space between the deceleration tube 12 and the tube wall 13, and does not participate in combustion, but can be used for cooling the deceleration tube 13 to avoid overheating and coking of the tube wall of the deceleration tube 13.

In addition, a combustion stabilization ring 17 is preferably provided on the inner wall of the rear end of the deceleration tube 12. The high-temperature flame that burns violently is broken by the combustion stabilization ring 17 to form a pulsating groove ring around the high-temperature torch, which is beneficial to the surrounding pulverized coal flow. The timely mixing intensifies the next stage of combustion.

In a preferred embodiment, a rich-lean separation block 2 is provided on the side wall at the rear end of the reduced-speed ignition combustion chamber 1, through which the pulverized coal in the reduced-speed ignition combustion chamber 1 moves closer to the center .

For the reduced-speed ignition combustion chamber in this embodiment, its output can be designed to be 500-2000 kg/h according to the characteristics of pulverized coal, and the nozzle temperature is not lower than 1200 °C.

Embodiment 2

In this embodiment, as shown in Figures 8-10, the burner includes a mixed combustion chamber 3 in addition to the above-mentioned reduced-speed ignition combustion chamber 1, and the mixed combustion chamber 3 is connected to the coal fired in the reduced-speed ignition combustion chamber 1. Powder outlet end (rear end). The mixed combustion chamber 3 is provided with a thick-lean separation pipe 31 axially in the center, the diameter of the rear end of the thick-lean separation pipe 31 is larger than the diameter of the deceleration pipe 12, and the thick-lean separation pipe 31 and the outer wall of the mixed combustion chamber 3 pass through at least one rib 32 connections. The pulverized coal that comes out from the deceleration pipe 12 is sprayed into the thick-lean separation pipe 31 of the mixed combustion chamber 3, and the pulverized coal in the thick-lean separation pipe 31 is ignited. A part also enters the thick-thin separation pipe 31, and the other part flows into the next stage from the gap between the thick-thin separation pipe 31 and the outer wall of the mixing combustion chamber 3, which is beneficial to the ignition of the mixing section and cools the wall of the mixing section. . Wherein, the above-mentioned ribs 32 can also be arranged in an arc shape, and have the same function as the above-mentioned support plate 14 .

In addition, since the thick-lean separation block 2 is provided on the side wall at the pulverized coal outlet end of the deceleration ignition combustion chamber 1, it can make most of the light coal powder between the deceleration tube 12 and the tube wall 13 enter the rich-thin separation tube. 31 participates in combustion, and only a very small part flows into the next stage from the gap outside the concentration separation pipe 31 against the wall.

Other structures, working principles, and beneficial effects of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

Embodiment 3

As shown in Figures 8-10, the burner can also include an oxygen supply enhanced combustion chamber 4, which is connected to the tail end of the mixing combustion chamber 3, so that all the pulverized coal in the mixing combustion chamber 3 enters the oxygen supply enhanced combustion chamber 4. The high-temperature flame in the oxygen supply enhanced combustion chamber 4 mixes with the dilute-phase pulverized coal and ignites the dilute-phase pulverized coal to realize the complete combustion of the pulverized coal. The volatile matter in the first two combustion chambers 1 and 3 is basically burnt out. In order to improve the burnout rate of loose charcoal, the measure of enhanced combustion with oxygen supplementation in advance is adopted. The oxygen supplementation in advance meets the oxygen amount required for pulverized coal combustion in time. The enthalpy of the oxygen supply enhanced combustion chamber 4 is increased, and then the muzzle velocity of the nozzle is increased, so as to achieve the purpose of enlarging the flame length and improving the degree of burnout.

Specifically, the inlet end of the oxygen supply enhanced combustion chamber 4 is sleeved on the outside of the tail end of the mixed combustion chamber 3 by means of the connecting plate 41, and an air supply port is formed between the two, and due to the reduced-speed ignition combustion chamber 1 and the mixed combustion chamber 3 In the two stages of combustion, the oxygen in the tube has been basically burned out, and the timely supplement of air from the air supply port strengthens the follow-up combustion of pulverized coal.

In a preferred embodiment, the supplementary air port in the oxygen supply enhanced combustion chamber 4 is a double-layer supplementary air port 42, there is a high-temperature flame in the burner spout, and there is heat radiation of the high-temperature flame in the furnace outside, and the secondary air (double-layer air ) enters the oxygen-supply enhanced combustion chamber 4 through the double-layer air supply port 42, which plays a cooling role on the inner layer and the outer wall, and has the effect of timely supplementing oxygen to enhance combustion; that is to say, the adopted perimeter cooling secondary air technology The oxygen used for combustion can be supplemented in time, and the problems of high-temperature flame burning out the burner and coking on the wall can be avoided. Because the burner is a burner with a thick inside and a thin outside, the volatile content of the airflow in the center of the outlet is very high and it is easy to catch fire after entering the furnace and contacting the high-temperature flame. It has a stable combustion capacity of 40% load and can replace the original main burner. Meet the needs of boiler startup, shutdown and low-load stable combustion.

Experiments have proved that the output of a single burner can reach more than 12t/h by using the above structure and principle.

Other structures, working principles, and beneficial effects of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

The above descriptions are only illustrative specific implementations of the present utility model, and are not intended to limit the scope of the present utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present utility model shall fall within the protection scope of the present utility model.

Claims (14)

1. A pulverized coal burner, characterized in that: the burner comprises a reduced-speed ignition combustion chamber, at least one socket is provided on the axial side wall of the reduced-speed ignition combustion chamber, and the socket is inserted There is an ignition device for igniting the pulverized coal passing through the reduced ignition combustion chamber. 2. The pulverized coal burner according to claim 1, characterized in that: said deceleration ignition combustion chamber includes a deceleration pipe, which is located at the front of the deceleration pipe, from the pulverized coal inlet end to the coal The cross-section in the direction of the powder outlet end is gradually enlarged, and the nozzle of the above-mentioned ignition device is located inside the deceleration tube, and is located at the position where the cross-section has been enlarged. 3. The pulverized coal burner according to claim 2, characterized in that: said deceleration ignition combustion chamber comprises a tube wall, said deceleration tube is axially arranged at the central position of the tube wall, and said deceleration tube The tube is connected to the tube wall via at least one support plate. 4. The pulverized coal burner according to claim 3, wherein the support plate is arranged in an arc shape. 5. The pulverized coal burner according to claim 3, characterized in that: the front end of the tube wall protrudes from the front end of the speed reduction tube in the axial direction, and the tube wall is provided with a A gradually expanding part, the cross section of the gradually expanding part in the direction from the pulverized coal inlet end to the pulverized coal outlet end is gradually enlarged. 6. The pulverized coal burner according to claim 5, characterized in that: on the inner surface of the tube wall, and at the axial position between the diverging part and the speed reduction tube, an eccentric Shade separation block. 7. The pulverized coal burner according to claim 5, characterized in that: at the position between the eccentric thick-lean separation block and the speed reduction tube, a thick powder guide tube is arranged on the central axis of the tube wall . 8. The pulverized coal burner according to claim 3, characterized in that: a combustion stabilizing ring is provided on the inner wall of the rear end of the deceleration tube. 9. The pulverized coal burner according to claim 3, characterized in that: a thick-thin separation block is arranged on the inner wall at the rear end of the tube wall of the decelerating combustion chamber. 10. The pulverized coal burner according to any one of claims 1-9, characterized in that the burner further comprises a mixing combustion chamber connected to the rear end of the reduced-velocity ignition combustion chamber. 11. The pulverized coal burner according to claim 10, characterized in that: a thick-thin separation pipe is arranged axially in the center of the mixing combustion chamber, and the diameter of the rear end of the thick-thin separation pipe is larger than the diameter of the above-mentioned speed-reducing pipe. The separating pipe is connected with the outer wall of the mixing combustion chamber through at least one rib. 12. The pulverized coal burner according to claim 11, wherein the ribs are arranged in an arc shape. 13. The pulverized coal burner according to claim 10, characterized in that: said burner further comprises an oxygen supply enhanced combustion chamber connected to the tail end of said mixing combustion chamber. 14. The pulverized coal burner according to claim 13, characterized in that: the inlet end of the oxygen supply enhanced combustion chamber is sleeved on the outside of the tail end of the mixing combustion chamber by means of a connecting plate, and a double-layer supplementary structure is formed between the two. tuyere.

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