JP3746642B2 - Pulverized coal concentration adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulverized coal concentration adjusting device in a pulverized coal pipe for supplying pulverized coal to a burner attached to a furnace of a pulverized coal combustion boiler.
[0002]
[Prior art]
A plurality of pulverized coal burners are attached to the furnace of the pulverized coal combustion boiler, and one primary distributor is provided for each of the two burners. This primary distributor has a small space for use near the coal mill, prevents the complication of the piping of the pulverized coal pipe (duct), and reduces the material cost. It is provided so that the pulverized coal pipe of the book can be shared.
[0003]
An example of the primary distributor is shown in FIG. The primary distributor 51 is connected to a pulverized coal pipe 53 in which pulverized coal 52 is sent by air and flows in the direction of arrow A, and branch pipes 54 and 55 branched to the left and right sides at a downstream position. In the interior, a plurality of stages of flow paths partitioned by a plurality of partition plates 56 are formed vertically and horizontally. Blind plates 57 are alternately arranged on the left and right sides in the vertical direction at the downstream ends of the flow paths of these stages, and the blind plates 57 block communication with one of the branch pipes 54 and 55. The pulverized coal 52 is blown into the flows 54 and 55 in a flow divided in the left and right directions (arrow B direction and C direction).
[0004]
That is, the pulverized coal 52 pulverized by a coal mill (not shown) is pneumatically transported to the primary distributor 51 through a plurality of pulverized coal pipes 53 and branched from each flow path of the primary distributor 51. It is supplied to a plurality of burners (not shown) provided in the furnace through the tubes 54 and 55 and burned by the burners.
[0005]
[Problems to be solved by the invention]
However, since the pulverized coal 52 that is pneumatically transported in the pulverized coal pipe 53 has a larger mass than air and tends to gravity settle, the concentration of the pulverized coal 52 flowing under the pulverized coal pipe 53 is high. The concentration distribution in the vertical direction becomes uneven at the inlet of the secondary distributor 51, and the distribution of the pulverized coal 52 supplied from the respective flow paths of the primary distributor 51 to the respective burners via the left and right branch pipes 54 and 55 is different. May occur, leading to an increase in NOx / unburned content.
[0006]
The present invention has been made in view of such a situation, and its object is to improve the concentration distribution in the vertical direction at the inlet of the primary distributor and to make the distribution of pulverized coal to each burner uniform. An object of the present invention is to provide a pulverized coal concentration adjusting device capable of achieving the above.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described problems of the prior art, the present invention is connected to a pulverized coal pipe in which pulverized coal is flown and flows, and is connected to a plurality of downstream branch pipes, and is formed over the top , bottom, left and right. A primary distributor that distributes and feeds the pulverized coal to each branch pipe from a plurality of stages of flow paths, and the pulverized powder to the branch pipe at a lower portion in the pulverized coal pipe on the upstream side of the primary distributor; A pulverized coal concentration adjusting device provided with solid-gas two-phase flow adjusting means for adjusting the charcoal concentration, wherein the solid-gas two-phase flow adjusting means is provided along the entire width of the pulverized coal pipe, and an upper surface thereof It is a kicker block having an inclined surface that gradually rises with respect to the flow direction of the pulverized coal, and the angle of the inclined surface can be adjusted according to the concentration of the pulverized coal flowing in the lower part of the pulverized coal pipe. It is configured .
[0008]
In the present invention, a wear-resistant material is provided on the inclined surface of the kicker block.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on illustrated embodiments. Here, FIG. 1 is a conceptual diagram of an attachment position of a primary distributor to which a pulverized coal concentration adjusting device according to an embodiment of the present invention is applied, and FIG. 2 is a pulverized coal concentration adjusting device and 1 according to the present embodiment. 3 is a perspective view of the vicinity of the installation of the next distributor, FIG. 3 is a conceptual diagram of a dispersion state of pulverized coal flowing through the pulverized coal pipe provided with the pulverized coal concentration adjusting device of FIG. 2, and FIG. 4 is a pulverized coal concentration adjustment of the present embodiment The diagram of the improvement effect confirmation test result by an apparatus is shown.
[0010]
The pulverized coal combustion boiler to which the pulverized coal concentration adjusting apparatus according to the embodiment of the present invention is applied generates heat by burning the supplied pulverized coal 1 with a pulverized coal burner 2, as shown in FIGS. A heat transfer tube group (not shown) that is arranged in parallel at a predetermined pitch above the furnace 3 to be generated, and that generates steam at a predetermined pressure and temperature by flowing steam inside and transmitting combustion heat from outside to generate heat. The combustion gas emitted from the pulverized coal combustion boiler is configured to be discharged from the chimney via an air preheater, an electric dust collector or the like (not shown).
Moreover, in connection with the said pulverized coal combustion boiler, the coal mill 4 which manufactures the pulverized coal 1 by grind | pulverizing the supplied coal is equipped, and the pulverized coal 1 is supplied from the coal mills 4 to 4 by pneumatic transportation. Eight pulverized coals that pass through the four pulverized coal pipes 5a to 5d, pass through the four primary distributors 6a to 6d and the branch pipes 7 and 8, and are attached to the outer periphery of the furnace 3 at a predetermined interval. It is supplied to each of the burners 2a to 2h.
[0011]
The primary distributors 6a to 6d have the same structure as in the prior art, and the pulverized coal 1 is fed by air and flows in the direction of arrow A, and the pulverized coal pipes 5a to 5d branch to the left and right sides at the downstream position. A plurality of flow paths 10 partitioned by a plurality of partition plates 9 are formed in the upper, lower, left, and right sides. On the downstream end side of the flow paths 10 of these stages, blind plates 11 are alternately arranged in the left and right directions in the vertical direction, and the blind plate 11 blocks communication with one of the branch pipes 7 and 8. In the branch pipes 7 and 8, the pulverized coal 1 is inflated by the flow divided into the left and right in the arrow B direction and the arrow C direction.
[0012]
Further, on the upstream side of the inlets of the primary distributors 6a to 6d, in the lower part of the pulverized coal pipes 5a to 5d, as shown in FIGS. A kicker block 12 of solid-gas two-phase flow adjusting means for adjusting the pulverized coal concentration to 7 and 8 is provided. The kicker block 12 constitutes the pulverized coal concentration adjusting device according to the embodiment of the present invention, and is provided along the entire width of the pulverized coal pipes 5a to 5d. An inclined surface 12a having an angle θ that gradually rises with respect to the flow direction (arrow A direction) is provided. That is, the kicker block 12 is formed on the downstream side (the inlet side of the primary distributors 6a to 6d) by the inclined surface 12a, and is formed in a substantially triangular cross section when viewed from the side. In addition, the code | symbol D has shown the pulverized coal density distribution in the pulverized coal pipes 5a-5d in FIG.
[0013]
In addition, the kicker block 12 can adjust the angle θ of the inclined surface 12a according to the concentration of the pulverized coal 1 flowing under the pulverized coal pipes 5a to 5d by using a known height position changing means or the like. It is configured. This adjustment operation of the angle θ is normally performed during the test operation after the completion of the apparatus, and each burner 2a to 2h during operation is changed and adjusted by changing the pulverized coal concentration to the branch pipes 7 and 8 on both the left and right sides. The distribution of the pulverized coal 1 is evenly distributed.
Further, the inclined surface 12a of the kicker block 12 is provided with a wear-resistant material 13 such as ceramics in order to prevent wear caused by the passing pulverized coal 1, and the wear-resistant material 13 includes a number of squares and the like. The tile pieces are fixed by attaching them with an adhesive or the like.
[0014]
Next, the operation of the pulverized coal concentration adjusting apparatus according to the embodiment of the present invention will be described.
First, when the pulverized coal 1 is sent from the coal mill 4 into the pulverized coal pipes 5a to 5d by pneumatic transportation, the pulverized coal 1 is directed to the primary distributors 6a to 6d as indicated by the arrow A direction. It flows in the pulverized coal pipes 5a to 5d. As shown in FIG. 3, the pulverized coal 1 flows under the pulverized coal pipes 5a to 5d by gravity sedimentation. At this time, the pulverized coal 1 hits the inclined surface 12a of the kicker block 12 of the solid-gas two-phase flow adjusting means and moves upward. As a result, the high concentration portion in the lowermost layer flows into the inlets of the primary distributors 6a to 6d while being dispersed.
Thereafter, the pulverized coal 1 in which such a high-concentration portion is dispersed is divided as shown by the arrows B and C from the flow passages 10 of the respective stages of the primary distributors 6a to 6d, while being branched downstream. 7, 8 is supplied to the burners 2a to 2h attached to the furnace 3, and burned by the burners 2a to 2h.
[0015]
In the pulverized coal concentration adjusting apparatus according to the embodiment of the present invention, the kicker block 12 provided with the inclined surface 12a at the lower part of the pulverized coal pipes 5a to 5d located on the upstream side of the primary distributors 6a to 6d is full-width. Therefore, the pulverized coal 1 flowing in the lower part of the pulverized coal pipes 5a to 5d can be dispersed and mixed upward, and the left and right branch pipes located on the downstream side of the primary distributors 6a to 6d. 7, 8 and the distribution of the pulverized coal 1 supplied to the burners 2a to 2h can be made uniform. When the density distribution improvement effect confirmation test in the height direction by the kicker block 12 was performed, the results as shown in FIG. 4 were obtained. As is clear from the figure, after the improvement as compared with before the improvement, the high concentration portion of the lowermost layer of the pulverized coal pipes 5a to 5d is dispersed by the installation of the kicker block 12, and the primary distributors 6a to 6d are dispersed. It can be seen that the variation in the concentration distribution in the vertical direction at the entrance is reduced and uniform.
In addition, since the kicker block 12 of the present embodiment is configured so that the angle θ of the inclined surface 12a is variable, the distribution ratio to the branch pipes 7 and 8 and the burners 2a to 2h can be easily changed even after the apparatus is completed. It is useful for adjusting the combustion of the burners 2a to 2h, and for reducing NOx / unburned content. In addition, since the wear resistant material 13 is provided on the inclined surface 12a of the kicker block 12, the durability of the kicker block 12 can be improved.
[0016]
As mentioned above, although embodiment of this invention was described, this invention is not limited to above-mentioned embodiment, In the range which does not deviate from the summary of this invention, a various deformation | transformation and change can be added. For example, in the present embodiment, the distribution is made to the two branch pipes 7 and 8 on the downstream side of the primary distributors 6a to 6d, but the upstream side of the primary distributor that distributes to three or more branch pipes. It is also possible to provide the kicker block 12.
[0017]
【The invention's effect】
As described above, the pulverized coal concentration adjusting device according to the present invention is connected to a pulverized coal pipe through which pulverized coal is flowed and is connected, and is connected to a plurality of downstream branch pipes, and is formed across the upper , lower, left and right sides. A primary distributor that distributes and feeds the pulverized coal to each branch pipe from a flow path in a stage, and pulverized coal to the branch pipe at a lower portion in the pulverized coal pipe on the upstream side of the primary distributor; Solid-gas two-phase flow adjusting means for adjusting the concentration is provided , the solid-gas two-phase flow adjusting means is provided along the entire width of the pulverized coal pipe, and the upper surface is a flow of the pulverized coal. The kicker block has an inclined surface that gradually rises with respect to the direction, and the kicker block is configured such that the angle of the inclined surface can be adjusted in accordance with the concentration of pulverized coal flowing in the lower part of the pulverized coal pipe . So pulverized coal flowing in the lower part of the pulverized coal pipe is dispersed and mixed upward Cause it becomes possible, and the distribution ratio of the device after completion even branch pipe can easily change, Ri FIG improved vertical is brought to a concentration distribution decreasing the variation in the concentration distribution of the inlet of the primary distributor, the final to be uniform pulverized coal distributed to each burner can Taseru useful standing in reducing NOx · unburned.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a mounting position of a primary distributor to which a pulverized coal concentration adjusting apparatus according to an embodiment of the present invention is applied.
FIG. 2 is a perspective view showing the vicinity of the installation of the pulverized coal concentration adjusting device and the primary distributor according to the embodiment of the present invention.
FIG. 3 is a conceptual diagram showing a dispersion state of pulverized coal flowing in a pulverized coal pipe provided with a pulverized coal concentration adjusting device according to an embodiment of the present invention.
FIG. 4 is a diagram showing test results for confirming the effect improved by the pulverized coal concentration adjusting apparatus according to the embodiment of the present invention.
FIG. 5 is a perspective view showing the vicinity of the installation of a conventional primary distributor.
[Explanation of symbols]
1 pulverized coal 2a to 2h pulverized coal burner 3 furnace 4 coal mills 5a to 5d pulverized coal pipes 6a to 6d primary distributors 7, 8 branch pipes 9 partition plates 10 flow paths 11 blind plates 12 kicker block (solid-gas two-phase flow Adjustment means)
12a Inclined surface 13 Wear resistant material

Claims (2)

The pulverized coal is connected to a plurality of pulverized coal pipes that are flown by air and connected to a plurality of downstream branch pipes, and the pulverized coal is distributed to the respective branch pipes through a plurality of stages of flow paths formed vertically and horizontally. comprising a primary distributor for pneumatically conveys Te, the lower portion of the pulverized coal pipe at the upstream side of the primary distributor, provided with a solid-gas two-phase flow adjusting means for adjusting the pulverized coal concentration to the branch pipe pulverized In the coal concentration adjusting device, the solid-gas two-phase flow adjusting means includes an inclined surface that is provided along the entire width of the pulverized coal pipe and whose upper surface gradually rises with respect to the flow direction of the pulverized coal. A pulverized coal concentration adjusting device, characterized in that the angle of the inclined surface can be adjusted according to the concentration of pulverized coal flowing in the lower part of the pulverized coal pipe . The kicker on the inclined surface of the block, pulverized coal concentration adjustment apparatus according to claim 1, characterized that you have wear resistant material is provided.

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