CN101329064A - Small amount of oil gasification combustion side to side multi-stage open ignition center powder swirl burner - Google Patents

Abstract

The utility model relates to a powder-feeding swirl burner for gasification combustion of a small amount of oil, and relates to a swirl burner. The purpose of the present invention is to solve the problem that when the existing micro-oil ignition swirl combustion device is applied to a large-capacity boiler, a large amount of pulverized coal needs to be ignited and a large-scale pulverized coal boiler using a swirl burner can reduce NOx emissions while the power plant boiler starts, The problem of fuel saving under the condition of stop and low load stable combustion. The first-stage combustion chamber of the present invention is fixed in the first air duct pipe at the front end of the support plate, the second-stage combustion chamber is fixed in the first air duct pipe at the front end of the first-stage combustion chamber, and the first air duct at the front side of the second-stage combustion chamber Inside the duct is the third-stage combustion chamber, and the main oil gun communicates with the primary air duct of the burner. The coal powder of the invention burns in a low-oxygen reducing atmosphere, prolongs the residence time of the coal powder, and can control the formation of combustion-type NOx. Since the secondary air is divided into inner and outer parts, staged combustion is formed, low NOx emissions are realized, and fuel is saved.

Description

Small amount of oil gasification combustion side to side multi-stage open ignition center powder swirl burner

technical field

The invention relates to a swirl burner.

Background technique

In the existing large-capacity power plant boilers, the amount of oil used for boiler ignition and low-load stable combustion is huge. In order to save fuel, power generation companies shift the focus of fuel saving from the low-load stable combustion process to the boiler ignition and shutdown process (when the power plant boiler starts and stops Fuel consumption accounts for 60%, low-load stable fuel consumption accounts for 40%). According to the traditional method, the ignition oil gun is arranged in the secondary air port of the burner. The distance between the oil gun and the pulverized coal nozzle is relatively far, and the two airflows are parallel to each other. Therefore, the heat generated by the fuel oil is directly used for heating during ignition. The part of pulverized coal is relatively small, and the heat utilization rate is low, so that when the boiler is ignited, the fuel consumption is very large. Micro-oil ignition technology is a new technology applied to power plant boiler start-up, stop and low-load stable combustion. The utility model patent whose Chinese patent number is ZL200520145352.2, authorized announcement number is CN2854368, and authorized announcement date is January 3, 2007 discloses a kind of "wide coal type micro-oil ignition burner". The Chinese patent application number is 200610053092.5, the publication number is CN1912462, and the invention patent published on February 14, 2007 discloses a swirling flow burner with "micro-oil cold furnace ignition, ultra-low load stable combustion and low NOx emissions" ", the oil guns of these two devices are all inserted into the primary air duct of the burner. When the burner is running, the casing of the oil gun is scoured by pulverized coal particles for a long time, which will easily cause the wear of the casing of the main oil gun. Once the wear occurs, the ignition of the small oil will not start, and it is difficult to meet the required service life. The service life requirements of the equipment are relatively high. On the other hand, the multi-stage combustion chambers of the above two devices are located behind the diversion cone or the pulverized coal concentrator and are connected to the outlet of the oil gun. The entire oil gun combustion device occupies a certain area in the center of the primary air duct of the burner. When the gun is used, the coal powder concentrated by the pulverized coal concentrator is concentrated on the outside of the central recirculation zone, so that the NOx is not reduced to the maximum extent. The Chinese patent application number is 200710072577.3, the publication number is CN101101115, and the invention patent published on January 09, 2008 discloses "a kind of powder swirl burner for gasification and combustion of small amount of oil, which is centrally ignited and fed to the center". The first-stage combustion chamber is arranged in an inverted "V" shape, which is very adaptable to small-capacity boilers, but when used in large-capacity boilers, the first-stage combustion chamber contains less concentrated coal powder in the center, and the first-stage combustion chamber has a lower concentration of coal powder , It is not conducive to the ignition of pulverized coal, and because there are only two stages of combustion chambers to ignite, the heat carried by the first stage of pulverized coal is small, and the second stage needs to be ignited too much pulverized coal, resulting in ignition failure.

Contents of the invention

The purpose of the present invention is to solve the problem that when the existing micro-oil ignition swirl combustion device is applied to a large-capacity boiler, a large amount of pulverized coal needs to be ignited and a large-scale pulverized coal boiler using a swirl burner can reduce NOx emissions while the power plant boiler starts, To solve the problem of fuel saving in the case of stoppage and low-load stable combustion, a kind of side-to-side multi-stage open ignition center-feeding powder swirl burner is provided. The invention includes a burner primary air duct, a concentration ring, a support plate, an inner swirler, an inner secondary air duct, an outer swirler, an outer secondary air duct, a burner, a support rod, and a third-stage combustion chamber , the second-stage combustion chamber, the first-stage combustion chamber, the main oil gun, the stopper, the first air duct pipe, the second air duct pipe and the third air duct pipe. The primary air duct of the burner is inside the first air duct pipe. The outlet end of the first air duct pipe is the burner, the support plate is fixed on the inlet end of the first air duct pipe, the concentration ring is fixed on the support plate, the first stage combustion chamber is fixed in the first air duct pipe at the front end of the support plate, The second-stage combustion chamber is fixed in the first air duct pipe at the front end of the first-stage combustion chamber, and the third-stage combustion chamber is inside the first air duct pipe at the front side of the second-stage combustion chamber. The main oil gun is connected with the primary air duct of the burner The outlet end of the main oil gun corresponds to the inlet end of the first-stage combustion chamber, the second air duct pipe is fixed on the front end of the outer surface of the first air duct pipe, and the gap between the second air duct pipe and the first air duct pipe It is the inner secondary air duct, the inner swirler is fixed in the inner secondary air duct, the third air duct pipe is fixed on the front end of the outer surface of the second air duct pipe, the distance between the third air duct pipe and the second air duct pipe The space is the external secondary air duct, the external cyclone is fixed in the external secondary air duct, the front ends of the first air duct pipe, the second air duct pipe and the third air duct pipe are connected to each other by the support rod, and the stopper is fixed on On the inner wall of the first air duct pipe at the rear end of the first-stage combustion chamber, the second-stage combustion chamber includes an upper plate and a lower plate, the upper end of the upper plate is fixedly connected with the upper inner wall of the first air duct pipe, and the lower end of the lower plate is connected with the upper inner wall of the first air duct pipe. The lower inner wall of the first air duct pipe is fixedly connected, the upper plate and the lower plate are arranged symmetrically in the first air duct pipe, and a gap is provided between the lower end of the upper plate and the upper end of the lower plate.

The invention has the advantages that after the pulverized coal airflow passes through the concentrator, a relatively high pulverized coal concentration is formed in the central area of the primary air passage of the burner, while the pulverized coal concentration is very low near the side wall. In the present invention, a stopper is set in front of the entrance of the first-stage combustion chamber to block part of the airflow of the light coal powder, and the concentration of coal powder in the first-stage combustion chamber is increased by 5% to 10%. Concentrated pulverized coal airflow is contained in the first-stage combustion chamber, which also increases the concentration of pulverized coal in the first-stage combustion chamber, which is beneficial to the ignition of pulverized coal. The second-stage combustion chamber is an open combustion chamber. When the pulverized coal combustion produces a large amount of smoke and causes excessive resistance, the smoke can enter the space outside the second-stage combustion chamber through the gap between the two plates of the second-stage combustion chamber. The air resistance is reduced, and this part of the heat properly heats the pulverized coal outside the second-stage combustion chamber, making it easier for the pulverized coal to be ignited when it enters the third-stage combustion chamber. The second stage combustion chamber burned out. Since the second-stage combustion chamber includes more areas with high pulverized coal concentration in the center, as the amount of pulverized coal input increases after the boiler is started, the amount of pulverized coal in the second-stage combustion chamber increases rapidly, and the combustion of the second-stage combustion chamber The heat released by the pulverized coal ignites the pulverized coal in the third-stage combustion chamber, further realizing the step-by-step amplification of energy, and greatly reducing the ignition energy required for pulverized coal combustion. The invention avoids the problem that the bushing of the oil gun is scoured by pulverized coal particles for a long time, which will easily cause the wear of the bushing of the main oil gun and cause the small oil ignition to fail to start, and the micro-oil ignition device does not change the low NOx and low NOx of the burner itself. Stable combustion characteristics; the invention improves the pulverized coal concentration of the first-stage combustion chamber by using the block and changing the shape of the combustion chamber, which is beneficial to the ignition of the coal powder. The problem of easy burning of the combustion chamber and the blockage of the flue gas in the combustion chamber is solved by using a multi-stage combustion chamber to solve the problem that a large amount of pulverized coal needs to be ignited when it is applied to a large-capacity boiler, which may easily lead to ignition failure. This burner can be used as the main burner during normal operation of the boiler. Since the secondary air enters the burner through the secondary air box, it is divided into two parts, which are respectively sent through the secondary air duct outside the burner and the secondary air duct inside the burner. Adjusting the opening of the inner and outer swirlers can change The ratio of internal and external swirling secondary air, the secondary air is rotated by the internal swirler and the external swirl, forming a central recirculation zone in the central area of the burner. The pulverized coal is injected into the central part of the central recirculation zone of the burner, the amount of pulverized coal passing through the central recirculation zone increases, and the pulverized coal burns in a low-oxygen reducing atmosphere, prolonging the residence time of pulverized coal and controlling combustion NOx generation. Since the secondary air is divided into inner and outer parts, staged combustion is formed, combined with central powder feeding, low NOx emissions are achieved, and a large amount of fuel is saved at the same time.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention, and Fig. 2 is the AA sectional view of Fig. 1, and Fig. 3 is the pulverized coal concentration distribution schematic diagram after the pulverized coal passes through the concentrator, wherein C is the pulverized coal concentration at the measuring point, and _C is the average coal concentration Powder concentration; R is the radius at the measuring point, and R ₀ is the radius of the primary air duct.

Detailed ways

Specific Embodiment 1: (See Figures 1 to 2) This embodiment includes a burner primary air duct 1, a concentration ring 2, a support plate 3, an inner swirler 4, an inner secondary air duct 5, and an outer swirler 6. External secondary air duct 7, nozzle 8, support rod 9, third-stage combustion chamber 10, second-stage combustion chamber 11, first-stage combustion chamber 12, main oil gun 15, stopper 16, first Air duct pipe 17, second air duct pipe 18 and third air duct pipe 19, the primary air duct 1 of the burner is inside the first air duct pipe 17, the outlet end of the first air duct pipe 17 is the burner 8, and the support plate 3 is fixed at the inlet end of the first air duct pipe 17, the concentration ring 2 is fixed on the support plate 3, the first-stage combustion chamber 12 is fixed in the first air duct pipe 17 at the front end of the support plate 3, and the second-stage combustion chamber 11 is fixed in the first air duct pipe 17 at the front end of the first-stage combustion chamber 12, the third-stage combustion chamber 10 is inside the first air duct pipe 17 on the front side of the second-stage combustion chamber 11, the main oil gun 15 and the burner The primary air duct 1 is connected, the outlet end of the main oil gun 15 corresponds to the inlet end of the first-stage combustion chamber 12, the second air duct pipe 18 is fixed on the front end of the outer surface of the first air duct pipe 17, and the second air duct Between the pipe 18 and the first air duct pipe 17 is the inner secondary air duct 5, the inner swirler 4 is fixed in the inner secondary air duct 5, and the third air duct pipe 19 is fixed on the second air duct pipe 18 The front end of the outer surface, between the third air duct pipe 19 and the second air duct pipe 18 is the outer secondary air duct 7, the outer swirler 6 is fixed in the outer secondary air duct 7, the first air duct pipe 17 , the front ends of the second air duct pipe 18 and the third air duct pipe 19 are connected to each other by the support rod 9, and the stopper 16 is fixed on the inner wall of the first air duct pipe 17 at the rear end of the first-stage combustion chamber 12, and the second-stage combustion chamber The chamber 11 includes an upper plate 11-1 and a lower plate 11-2, the upper end of the upper plate 11-1 is fixedly connected with the upper inner wall of the first air duct pipe 17, and the lower end of the lower plate 11-2 is connected with the first air duct pipe 17. The lower inner wall of the lower side is fixedly connected, the upper plate 11-1 and the lower plate 11-2 are symmetrically arranged in the first air duct pipe 17, and a gap 11 is provided between the lower end of the upper plate 11-1 and the upper end of the lower plate 11-2 -3.

Specific implementation mode two:. (See Fig. 1～Fig. 2) The difference between this embodiment and the specific embodiment one is that it increases the auxiliary oil gun 13, the auxiliary oil gun 13 is arranged in parallel with the main oil gun 15, and the auxiliary oil gun 13 is connected with the first stage combustion The chambers 12 communicate with each other, and the outlet end of the auxiliary oil gun 13 is arranged in the middle of the first-stage combustion chamber 12 . Others are the same as in the first embodiment.

Specific embodiment three: (referring to Fig. 1～Fig. 2) the difference between this embodiment and specific embodiment two is that it has increased flame detection device 14, and flame detection device 14 is arranged on auxiliary oil gun 13 and main oil gun 15 During this period, the flame detection device 14 communicates with the first-stage combustion chamber 12 . Others are the same as in the second embodiment.

The pulverized coal is sent into the primary air duct 1 of the burner, and the pulverized coal is concentrated through the pulverized coal concentrator 2, and a high concentration of pulverized coal is formed in the central area of the primary air duct 1 of the burner. The 600MW subcritical boiler is calculated by fluent software The concentration distribution results are shown in Figure 3. The high concentration area of pulverized coal is within 0.6R ₀ where the center of the primary air duct 1 is the center of the circle, and the rest is the airflow of light pulverized coal. A block is set in front of the _entrance of the first-stage combustion chamber 12 to block part of the airflow of light coal powder. The high-concentration pulverized coal in the annular area 1/4 of R ₀ to 0.6R ₀ enters the first-stage combustion chamber 12, and the high-temperature flame formed by the main oil gun 15 directly contacts with the dense coal powder particles in the first-stage combustion chamber 12 to make the coal The characteristics of the powder particles change, and the extremely high heating rate greatly accelerates the precipitation of volatile matter. The temperature of the coal powder particles rises sharply, bursts, smashes and burns violently. When the flame is unstable, the auxiliary oil gun 13 can be used in time to help Pulverized coal burns. Then the ignited high-temperature pulverized coal airflow enters the second-stage combustion chamber 11 to contact with the pulverized coal particles in the second-stage combustion chamber and ignites the coal powder in the second-stage combustion chamber 11. The second-stage combustion chamber 11 has an open slit structure and reduces This part of the heat heats the pulverized coal outside the second-stage combustion chamber, making it easier for the pulverized coal to be ignited when it enters the third-stage combustion chamber, and finally enters the third-stage combustion chamber. The remaining pulverized coal is ignited in the combustion chamber to realize the staged combustion of the pulverized coal, the combustion energy is amplified step by step, and finally sprayed into the furnace through the burner 8 . The support plate 3 is used to fix the concentration ring, and the support rod 9 is used to fix the inner secondary air duct 5 and the outer secondary air duct 7 . The secondary air enters the burner through the secondary air box and is divided into two parts, which are respectively supplied through the secondary air duct 7 outside the burner and the secondary air duct 5 inside the burner, and the opening of the inner and outer swirlers can be adjusted. The ratio of the secondary air of the internal and external swirls is changed, the secondary air is rotated by the internal swirler 4 and the external swirl 6, and a central recirculation zone is formed in the central area of the burner. The pulverized coal is injected into the central part of the central recirculation zone of the burner, the amount of pulverized coal passing through the central recirculation zone increases, and the pulverized coal burns in a low-oxygen reducing atmosphere, prolonging the residence time of pulverized coal and controlling combustion NOx generation. Since the secondary air is divided into inner and outer parts, staged combustion is formed, and combined with central powder feeding, low NOx emissions are achieved.

Claims (3)

1, a kind of small oil mass gasification combustion side direction multilevel open type igniting center powder-feeding swirling burner, it comprises an air channel of burner (1), concentrate ring (2), gripper shoe (3), interior cyclone (4), interior secondary wind air channel (5), outer cyclone (6), outer secondary wind air channel (7), nozzles (8), support bar (9), third level combustion chamber (10), combustion chamber, the second level (11), first-stage burning chamber (12), main oil gun (15), block (16), first wind channel tube (17), second wind channel tube (18) and the 3rd wind channel tube (19), in first wind channel tube (17) is an air channel of burner (1), the port of export of first wind channel tube (17) is nozzles (8), it is characterized in that: gripper shoe (3) is fixed on the arrival end in first wind channel tube (17), concentrating ring (2) is fixed on the gripper shoe (3), first-stage burning chamber (12) is fixed in first wind channel tube (17) of gripper shoe (3) front end, combustion chamber, the second level (11) is fixed in first wind channel tube (17) of first-stage burning chamber (12) front end, in first wind channel tube (17) of front side, combustion chamber, the second level (11) is third level combustion chamber (10), main oil gun (15) is connected with an air channel of burner (1), the port of export of main oil gun (15) is corresponding with the arrival end of first-stage burning chamber (12), second wind channel tube (18) is fixed on the front end of first wind channel tube (17) outer surface, be interior secondary wind air channel (5) between second wind channel tube (18) and first wind channel tube (17), interior cyclone (4) is fixed in the interior secondary wind air channel (5), the 3rd wind channel tube (19) is fixed on the front end of second wind channel tube (18) outer surface, be outer secondary wind air channel (7) between the 3rd wind channel tube (19) and second wind channel tube (18), outer cyclone (6) is fixed in the outer secondary wind air channel (7), first wind channel tube (17), the front end of second wind channel tube (18) and the 3rd wind channel tube (19) is interconnected by support bar (9), block (16) is fixed on the inwall of first wind channel tube (17) of rear end, first-stage burning chamber (12), combustion chamber, the second level (11) comprises upper plate (11-1) and lower plate (11-2), fixedly connected with the upper inside walls of first wind channel tube (17) in the upper end of upper plate (11-1), fixedly connected with the downside inwall of first wind channel tube (17) in the lower end of lower plate (11-2), upper plate (11-1) and lower plate (11-2) are symmetrical arranged in first wind channel tube (17), are provided with slit (11-3) between the upper end of the lower end of upper plate (11-1) and lower plate (11-2).

2, small oil mass gasification combustion side direction multilevel open type igniting according to claim 1 center powder-feeding swirling burner, it is characterized in that: turbulent burner also comprises auxiliary oil gun (13), auxiliary oil gun (13) be arranged in parallel with main oil gun (15), auxiliary oil gun (13) is connected with first-stage burning chamber (12), and the port of export of auxiliary oil gun (13) is arranged on the middle part of first-stage burning chamber (12).

3, small oil mass gasification combustion side direction multilevel open type igniting according to claim 2 center powder-feeding swirling burner, it is characterized in that: turbulent burner also comprises fire monitor equipment (14), fire monitor equipment (14) is arranged between auxiliary oil gun (13) and the main oil gun (15), and fire monitor equipment (14) is connected with first-stage burning chamber (12).

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