CN201787567U - DC pulverized coal burner - Google Patents

Abstract

The utility model relates to a direct-flow pulverized coal burner, which is stable in burning and excellent in oil-saving performance, and comprises a burner body outer casing consisting of an inlet pipeline, a Venturi concentrator and jet pipe in sequential connection. An oil-burning air pipe and an oil burning device positioned at the center of the oil-burning air pipe are further arranged in the burner. The direct-flow pulverized coal burner is characterized in that a rectifying concentration separating device is arranged in the inlet pipeline, an upper concentration separating partition plate and a lower concentration separating partition plate are symmetrically arranged in the jet pipe according to the central line of the burner body outer casing, a flow expansion cone is arranged between each concentration separating partition plate and an outlet expansion section of the Venturi concentrator, the top of the flow expansion cone points at the necking position of the Venturi concentrator; the oil-burning air pipe penetrates through the flow expansion cone; and a burning supporting air passage is communicated with the inside of a jet of the jet pipe.

Description

DC pulverized coal burner

technical field

The utility model relates to a burner, in particular to a direct-flow pulverized coal burner.

Background technique

Coal is the main energy source in our country. Although our country is rich in coal resources, the types of coal are varied and the quality of coal is poor. In recent years, the domestic coal supply situation has continued to deteriorate, and coal prices have continued to rise. In order to reverse losses and increase profits, major domestic power generation companies have generally implemented the strategy of blending coal to reduce power generation costs. A large number of inferior coal with high ash content and low calorific value are burned Coal, resulting in reduced unit operation stability, high-load fire extinguishing phenomenon occurs from time to time, and frequent start-ups increase start-up fuel consumption; in addition, reduced combustion stability will also increase auxiliary fuel consumption. In response to this situation, it is necessary and timely to develop low-quality coal combustion technology.

According to the current situation of coal supply in my country, the market demands pulverized coal combustion technology with higher comprehensive performance. The current fuel-saving technology has a significant effect in starting and saving fuel. The application effect on coal and worse coal units is not good; although the current stable combustion technology can significantly enhance the unit's stable combustion and peak regulation capabilities, it basically does not have the function of starting fuel saving.

Contents of the invention

The problem to be solved by the utility model is to improve the existing pulverized coal burner and provide a direct current pulverized coal burner with stable combustion and excellent fuel-saving performance.

The technical solution to solve the above problems is: the provided direct-flow pulverized coal burner includes a burner body casing formed by sequentially connecting the inlet pipe, the Venturi concentrator and the nozzle pipe, and the burner is also provided with an oil combustion air duct and a The oil combustion device in the center of the oil combustion air duct, the improvement of the utility model is: a rectification thick-thin separation device is installed in the inlet pipe, and the upper and lower thick-thin separation partitions are symmetrically arranged in the nozzle pipe according to the center line of the burner body shell. A diffuser cone is set between the partition and the outlet expansion section of the Venturi concentrator. The cone top of the diffuser cone points to the constriction of the Venturi concentrator. Inside the nozzle of the nozzle tube.

The role of the combustion-supporting air duct is to cool the nozzle of the nozzle pipe and supplement the combustion air. The chamber between the upper and lower thick-thin separation partitions is the primary pulverized coal combustion chamber, and the chamber at the nozzle of the nozzle pipe is the secondary pulverized coal combustion chamber. The pulverized coal airflow enters the inlet pipe, and the particle distribution of the pulverized coal airflow is optimized and adjusted by the rectification and concentration separation device in the inlet pipe, and then enters the Venturi concentrator for secondary concentration separation. The concentration separation partition can be divided to maintain the pulverized coal flow The thick-thin separation flow state. Most of the light pulverized coal flow enters the channel between the thick-lean separation partition and the upper and lower walls of the nozzle; a small part of the dense coal powder flow enters the passage between the diffuser cone and the dense-lean separation partition, and the channel between the diffuser cone and the inner wall of the nozzle tube and The passage between the two side walls of the venturi concentrator outlet expansion section; the dense coal powder gas flow entering from the passage between the diffuser cone and the thick-lean separation partition is blocked by the recirculation zone in the first-stage pulverized coal combustion chamber behind the cone. After the airflow is processed in this way, its combustion stability ability is greatly enhanced, and the fuel consumption is also greatly reduced.

There are two options for the above-mentioned oil combustion air duct to penetrate the diffuser cone: the oil combustion air duct penetrates the diffuser cone along the center line of the diffuser cone or the oil combustion air duct obliquely penetrates the diffuser cone.

The above-mentioned combustion-supporting air duct can also be configured in this way: an air film bellows is arranged outside the burner body shell, and a combustion-supporting air duct is formed between the air film bellows and the burner body shell.

The utility model has the advantages that: since the pulverized coal airflow is separated by density for many times, it forms a density separation flow state that is very suitable for the combustion of the pulverized coal airflow, and it will inevitably form a graded gas supplement effect, so that the combustion of residual charcoal can obtain timely and sufficient oxygen. supply, the combustion efficiency is improved, and the carbon content of fly ash is reduced, so as to achieve the purpose of improving boiler efficiency and reducing coal consumption. Due to the adoption of multiple thick-thin separation measures and the establishment of multiple channels for gradually entering the dense-phase airflow, the fuel-saving rate is greatly improved under the condition that the stable combustion ability is further enhanced.

Description of drawings

Fig. 1 is a schematic structural diagram of the first embodiment of the utility model.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is a schematic structural diagram of the second embodiment of the utility model.

FIG. 4 is a top view of FIG. 3 .

Detailed ways

Below in conjunction with accompanying drawing, the content of the present utility model is described in detail.

The first embodiment of the utility model is shown in Fig. 1 and Fig. 2 . The inlet pipeline 1, the Venturi concentrator 5 and the nozzle pipe 9 are connected in sequence to form the shell of the burner body, and the oil combustion device 4 is located at the center of the oil combustion air duct 3. The rectification thick-lean separation device 2 is installed in the inlet pipe 1, the upper and lower thick-lean separation partitions 8 are arranged symmetrically in the nozzle pipe 9, and the diffuser cone 7 is arranged between the partition 8 and the outlet expansion section of the Venturi concentrator 5, and the oil combustion wind The pipe 3 runs through the diffuser cone 7 along the centerline of the diffuser cone 7 (the oil combustion air duct 3 can also pass through the diffuser cone 7 obliquely, that is, the centerline of the oil combustion air duct intersects the centerline of the diffuser cone Angle at a certain angle), the combustion-supporting air duct 61 leads to the nozzle of the nozzle pipe 9 (see Fig. 2). The outlet of the oil combustion air duct 3 is connected to the oil combustion chamber 12, the chamber between the upper and lower thick-lean separation partitions 8 is the first pulverized coal combustion chamber 13, and the chamber at the spout of the spout pipe is the pulverized coal secondary combustion chamber 14.

The sections of the spout pipe 9 and the Venturi concentrator 5 of the present example are all rectangular, and the upper and lower walls of the spout pipe 9 are flush with the outlet end of the Venturi concentrator 5; Form a contraction cone shape that is symmetrical up and down; the two side walls of the nozzle pipe 9 are of double-layer structure, forming a combustion-supporting air duct 61, the inner side wall 92 of the nozzle pipe is flush with the Venturi concentrator 5, and the outlet of the inner side wall 92 of the nozzle pipe is a triangle Shaped protrusion 93.

The diffuser cone 7 of the present example is a triangular cone, and the sidewall of the diffuser cone 7 forms a small channel 71 with the inner wall 92 of the spout pipe and the two sidewalls of the Venturi concentrator 5 outlet expansion section, and the diffuser cone A plurality of rectangular column blocks 72 are arranged up and down on the bottom end surface of 7, and viewed from direction A, the plurality of rectangular column blocks 72 are in the shape of a Great Wall flower.

Fig. 3, Fig. 4 have provided the second embodiment of the present utility model. An air film bellows 6 is arranged outside the burner body shell, and at this time, a combustion-supporting air duct 61 is formed between the air film bellows 6 and the burner body shell. The inlet of the air film bellows 6 is provided with a damper 10 for adjusting the air volume of the combustion air W3. Wall temperature measuring thermocouples 11 are respectively arranged on the wall surfaces of the oil combustion chamber 12, the first-level pulverized coal combustion chamber 13, and the secondary pulverized coal combustion chamber 14 (the Belbin example has only drawn the heat of the secondary pulverized coal combustion chamber 14 wall surfaces) I). Other structures of this example are the same as those of the first embodiment.

The working principle of the burner will be described below in conjunction with the second embodiment.

The wind W2 used for fuel oil enters the fuel oil air pipe 3, and the pulverized coal airflow W1 enters the inlet pipe 1. After passing through the rectified thick-thin separation device 2, the pulverized coal airflow realizes the separation optimization and adjustment of particle distribution, and realizes the second time after entering the Venturi concentrator 5. Air concentration is separated, most of which are light pulverized coal airflow w1d, entering the channel between the partition plate 8 and the upper and lower walls of the nozzle pipe 9; a small part is dense coal pulverized airflow w1n, and most of the dense coal pulverized airflow enters the diffuser cone 7 The upper and lower passages between the upper and lower partitions 8, a small part enters the small passage 71 between the inner side wall of the spout pipe and the two side walls of the venturi concentrator outlet expansion section. Most of the light pulverized coal airflow entering the channel between the partition 8 and the upper and lower walls is affected by the deflection inertia, clings to the upper and lower walls, and is sprayed into the furnace in the form of a wall-attached jet. The shrinking cone structure at the exit can make the part of the air flow The pulverized coal particles bend to move toward the center, the gas inertia is small, and the expansion angle of the air flow around the near wall is increased, the main jet is still jetted against the wall, and a large amount of high-temperature flue gas in the furnace is entrained into the pulverized coal. Inside the secondary combustion chambers 13 and 14.

After the dense pulverized coal gas flow entering the upper and lower passages between the diffuser cone 7 and the upper and lower partitions 8 bypasses the diffuser cone, it acts on the rectangular column block 72 on the end surface, blocks the deceleration and thickens in the positive pressure low-speed zone of the recirculation zone, Under the comprehensive action of the triangular inclined plane of the outlet section of the partition 8, the part of the airflow is concentrated efficiently, and the coal powder particles are classified and moved to the center; a small part of the concentrated coal powder airflow entering the small channels 71 on both sides, after the expansion cone Affected by the diversion of the triangular slope, it quickly flows to the middle area.

The high-temperature flue gas that flows back into the first-stage pulverized coal combustion chamber 13 is strongly mixed with the high-concentration pulverized coal airflow that moves towards the center in a graded direction, and completes extremely high heat and mass exchange and is rapidly heated, and a large amount of volatile matter is rapidly precipitated and ignited. , form a stable ignition area, and continuously ignite the main pulverized coal airflow with the airflow diffusion, so that the pulverized coal airflow can be burned stably and in advance, and the stable combustion ability is greatly enhanced. capacity and reduce fuel consumption.

In the cold state ignition start-up process, the temperature level in the furnace is low, and the heat released by the ignition oil gun burning in the oil combustion chamber 12 only needs to meet the ignition requirements of the concentrated coal powder flow entering the center part of the first-level pulverized coal combustion chamber 13, so the heat required is extremely high. This part of the pulverized coal will be ignited and burned, and then the main pulverized coal airflow will be ignited successively by the return flow zone and air flow diffusion, so that the energy level will be continuously enlarged, and the cold ignition start-up process will be completed with very little fuel consumption, greatly reducing Fuel consumption in the process of ignition and starting, to achieve the purpose of starting fuel consumption.

The temperature-measuring thermocouples provided on the walls of the oil combustion chamber 12, the primary pulverized coal combustion chamber 13, and the secondary pulverized coal combustion chamber 14 respond to changes in wall temperature in time, and the measured temperature indirectly reflects the combustion conditions in each combustion chamber. If the temperature is higher than The allowable temperature limit of the wall surface can be opened to cool the nozzle by air film air, or reduce the output of the oil gun, so that the burner can always work below the safe temperature limit.

From the above working process, it can be seen that regardless of the cold ignition start-up or the normal operation process, the high-concentration pulverized coal in the center of the pulverized coal primary combustion chamber is in a state of rapid heating, rapid precipitation of a large amount of volatile matter, and ignition and combustion in an oxygen-poor environment. , which greatly suppresses the generation of nitrogen oxides; in the secondary pulverized coal combustion chamber, the light-phase air flow is mixed in, and the combustion air is replenished in time to intensify the combustion. Because the secondary air has not been mixed in, so the formation is still a high-temperature reducing flame. The reduction of nitrogen oxides produced by the combustion of centrally concentrated pulverized coal can greatly reduce the concentration of nitrogen oxide emissions and achieve the purpose of protecting the environment.

Claims (6)

1. straight-through pulverized coal burner, comprise by inlet duct (1), the burner body shell that venturi inspissator (5) and jet pipe (9) are connected to form in turn, also be provided with oil firing airduct (3) in the burner and be positioned at the oil combustion device (4) at oil firing airduct center, it is characterized in that: rectification light-dark separation device (2) is set in the inlet duct (1), center line by the burner body shell in jet pipe is symmetrical arranged deep or light separation dividing plate (8) up and down, between the outlet expanding section of deep or light separation dividing plate (8) and venturi inspissator (5), be provided with and expand flow cone body (7), this expands the bottleneck that flow cone body (7) vertex of a cone points to venturi inspissator (5), oil firing airduct (3) runs through expansion flow cone body (7), and combustion-supporting air channel (61) are led in the spout of jet pipe (9).

2. coal burner according to claim 1 is characterized in that oil firing airduct (3) runs through expansion flow cone body 7 two kinds of selection modes are arranged: flow cone body (7) center line runs through expansion flow cone body to oil firing airduct (3) or oblique running through of oil firing airduct (3) expanded flow cone body (7) along expanding.

3. coal burner according to claim 1 is characterized in that the outer setting air film bellows (6) at the burner body shell, forms combustion-supporting air channel (61) between air film bellows (6) and the burner body shell.

4. coal burner according to claim 3 is characterized in that the inlet of air film bellows (6) is provided with damper (10).

5. according to each described coal burner of claim 1 to 4, it is characterized in that the cross section of jet pipe (9) and venturi inspissator (5) is all rectangular, jet pipe (9) is gone up lower wall and venturi inspissator (5) concordant joining of the port of export; Inwall up and down in jet pipe (9) exit is contraction inclined-plane (91), forms laterally zygomorphic contraction taper; Jet pipe (9) two side is a double-decker, forms combustion-supporting air channel (61), jet pipe madial wall (92) and concordant joining of venturi inspissator (5), and jet pipe madial wall (92) exit is triangular shape projection (93).

6. coal burner according to claim 5, it is characterized in that expanding flow cone body (7) and be the triangle cone, form passage aisle (71) between the two side of the sidewall of expansion flow cone body (7) and jet pipe madial wall (92) and venturi inspissator (5) outlet expanding section, expand the bottom end face of flow cone body (7) and arrange a plurality of rectangular column pieces (72) up and down, from A to, a plurality of rectangular column pieces (72) are a Great Wall shape.

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