JP3664838B2 - Pulverized coal combustor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulverized coal combustor applied to a boiler for power generation or private power generation such as a factory.
[0002]
[Prior art]
A conventional one will be described with reference to FIG. The figure schematically shows the situation until the pulverized coal conveyed through a predetermined path is ejected into the furnace.
[0003]
That is, the pulverized coal that has been transported in the pulverized coal pipe 1 together with the primary air is jetted into the furnace from the burner provided at the tip thereof, but the pulverized coal is caused by centrifugal force at the bent portion 2 that passes in the path to reach here. Although drift occurs, it is returned to the center by contacting the kicker 3 disposed immediately after the bent portion 2.
[0004]
The pulverized coal is rectified by the core 4 disposed subsequently path, thinner central portion 5, to form a thick pulverized coal concentration distribution of the peripheral portion 6, configured to achieve stable ignition and low NO _X combustion Has been.
[0005]
[Problems to be solved by the invention]
As described above, in the conventional combustor for pulverized coal, the pulverized coal transport pipe from the not-illustrated coal pulverizer to the burner has many bent portions 2 in the middle. The concentration distribution in the pulverized coal pipe is generated by the centrifugal force.
[0006]
Further, the pulverized coal drifts by passing through such a bent portion 2 several times, and a spiral pulverized coal high-concentration portion is formed in the pulverized coal pipe 1. In the case where the high concentration portion does not come to the position of the kicker 3 depending on the flow rate condition, or the spiral high concentration portion remains even after passing through the core 4 and the rectification of the pulverized coal is not performed. eventually, there may not be a stable ignition, optimization of the pulverized coal concentration distribution for the low nO _X.
[0007]
Problem in the present invention is to solve such problems in the prior art, a simple structure, optimizes the pulverized coal concentration distribution, to provide what was to achieve a low NO _X reduction with stable ignition It is what.
[0008]
[Means for Solving the Problems]
The present invention has the problems described above were solved all Kunasa, as a first means, the helical rifles plate is provided in the final of the inner surface of the straight pipe portion of the pulverized coal pipe for guiding the pulverized coal to the burner, the rifle The spiral curved surface of the plate provides a pulverized coal combustor formed on a spiral surface opposite to the spiral drift of the pulverized coal mixture conveyed in the pulverized coal pipe, and is generated at a bent portion in the pulverized coal pipe helical and a spiral surface of the pulverized coal drift and opposite, since the disposed rifle plate issued Ri Zhang pulverized coal pipe so as to face in the pulverized coal drift, pulverized coal drift this rifle The uneven flow is canceled by colliding with the plate, and the flow is adjusted so that the flow becomes a uniform distribution and the flow is smooth so that, for example, the rectifying action can be suitably performed.
[0009]
Further, the present invention is a second means, the final plurality of fins on the inner surface of the straight tube portion of the pulverized coal pipe for guiding the pulverized coal to the burner to array on a spiral streamline, the sequence is the sequence of the fin spiral streamlines provides pulverized coal burner which is arranged to symmetrically flow lines are formed for any direction around counterclockwise or the right, of the pulverized coal pipe final of in formation A plurality of fins arranged on a spiral streamline on the inner surface of the straight pipe part, the spiral streamline forming the fin as a whole in the same fin array is symmetrical in either the counterclockwise or clockwise direction As a result, the spiral pulverized coal drift generated at the bent portion in the pulverized coal pipe has the same direction as the spiral arrangement direction of the fins. However, even in the opposite direction, it will collide with either the front or back side of the fin. The are intended to be adjusted so that a smooth flow pulverized coal drift is canceled becomes uniform flow of distribution, can be suitably performed, for example, rectification, etc. In the wake position.
In addition, as a third means, the present invention provides a nozzle part of a pulverized coal pipe downstream of the spiral rifle plate or the plurality of fins arranged on the spiral streamline in the first or second means. Upstream of the pulverized coal combustor provided with a core for separating the pulverized coal flow in the center of the pulverized coal pipe, and arranged on the spiral rifle plate or spiral streamline The flow of pulverized coal, which has been distributed uniformly by canceling the spiral drift by a plurality of fins, is surely suitable for the density by the core located in the center of the pulverized coal pipe at the downstream position. Separation takes place.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. In addition, about the same part as the above-mentioned conventional thing, the same code | symbol is attached | subjected and shown in a figure, and the overlapping description is abbreviate | omitted.
[0011]
1 and 2, reference numeral 1 denotes a pulverized coal transport pipe, which transports pulverized coal together with primary air by a transport device (not shown). 4 is a core that separates the flow of pulverized coal into dark and light, and is disposed in the center of the pulverized coal transport pipe 1 in front of the nozzle portion of the pulverized coal transport pipe 1.
[0012]
Reference numeral 7 denotes a rifle plate disposed upstream of the core 4 at a downstream position of the bent portion 2 of the pulverized coal transport pipe 1 and having a continuous spiral shape protruding from the inner wall of the pulverized coal transport pipe 1 toward the inside of the pipe. It is composed of a plurality of plates.
[0013]
Reference numeral 8 denotes a pulverized coal mixture that has been conveyed with spiral drift in the pulverized coal transport pipe 1 together with the primary air, and the spiral curved surface of the rifle plate 7 is bent by this drift. It is formed in a shape facing the direction.
[0014]
In this embodiment configured as described above, the spiral drift is generated through some bent portions of the pulverized coal transport pipe 1, and the spiral drift is emphasized by the bent portion 2 at the final position. The charcoal mixture 8 collides with the rifle plate 7 arranged with a spiral opposite to the drift, and the drift is canceled out to have a uniform distribution.
[0015]
Thereafter, the core 4 is separated shading of pulverized coal is injected into the furnace, darker periphery distribution 6, the thin pulverized coal density distribution of the center portion distributions 5 is formed, achieve stable ignition and low NO _X To do. Further, the air flow is also swirled by the rifle plate 7, thereby further forming the division of the central portion distribution 5 and the peripheral portion distribution 6.
[0016]
The rifle plate 7 extends about twice as long as the inner diameter of the pulverized coal conveying pipe 1 is D, that is, extends over a range of 2D. As shown in FIG. Further, six sheets are arranged by dividing the circumferential direction into six equal parts.
[0017]
The thickness B of the rifle plate 7 is preferably about 10 to 30 mm in consideration of its workability and wear resistance, and the height H protruding toward the inside of the pipe is the inner diameter D of the pulverized coal transport pipe 1. It is preferable to be 0.1 to 0.3 times with respect to.
[0018]
That is, the height H of the rifle plate 7 is required to be 0.1D or higher in order to effectively eliminate the drift of the pulverized coal that collides with the rifle plate 7, and this height is limited to that purpose. The higher the thickness, the better. However, considering the difficulty of processing, about 0.3D is the limit, so 0.1D is set as the lower limit and 0.3D is set as the upper limit.
[0019]
In this example, the number of rifle plates 7 is six, but the number N of rifle plates 7 is practically about 3 to 8.
[0020]
Further, the inner diameter D of the pulverized coal conveyance pipe 1 is generally 300 to 500φ. If the inner diameter D is 500 mm, the thickness B is 20 mm and the height as the rifle plate 7 suitable for this size. A preferable example is that H is 0.2 mm and 100 mm, and the number of sheets is six.
[0021]
Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those of the conventional one and the first embodiment described above are denoted by the same reference numerals in the drawings, and redundant description is omitted.
[0022]
In this embodiment, instead of the rifle plate 7 in the first embodiment, a plurality of small rectifying fins 9 are arranged at this position.
[0023]
In other words, in the present embodiment, a plurality of small rectifying fins 9 are distributed over the inner diameter D of the pulverized coal transport pipe 1 approximately twice that of the pulverized coal conveyance pipe 1, that is, 2D, and each small rectifying fin 9 is upstream. From the one arranged on the side to the one arranged on the downstream side, they are arranged so as to be distributed on the spiral streamline.
[0024]
In addition, this spiral streamline is an arrangement of the rectifying fins 9 such that the streamlines are formed symmetrically with respect to either the left-handed direction or the right-handed direction. If it sees, as FIG. 3 shows, each longitudinal direction is arrange | positioned toward the direction parallel to the axis line of the pulverized coal conveyance pipe | tube 1. As shown in FIG.
[0025]
Therefore, in the present embodiment, the pulverized coal mixture 8 in which the spiral drift is generated via some bent portions of the pulverized coal transport pipe 1 is flow-rectified fins arranged along the spiral streamline. 9 collides with each other, and the drift is canceled out and a uniform distribution is obtained.
[0026]
In addition, in the present embodiment, since the arrangement of the respective rectifying fins 9 is an arrangement in which a spiral streamline can be drawn symmetrically in either of the left and right directions, the pulverized coal mixture 8 is spirally drifted from either the left or right. Even if it exists, since each rectification fin 9 is formed with the small member which became independent independently, the work of the manufacture, integration, etc. is easy.
[0027]
As an example of the rectifying fin 9, the length L is about 100 mm, the plate thickness is 10 to 30 mm, and the height is 0.1 to 0.3 times the inner diameter D of the pulverized coal conveyance pipe 1 (0.1 D -0.3D), the arrangement interval M in the axial direction is about 100 mm, and the arrangement interval in the circumferential direction is a phase of 120 ° to 45 °, and 3-8 pieces are arranged in the circumferential direction. Is desirable.
[0028]
Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to this embodiment, and it goes without saying that various modifications may be made to the specific structure within the scope of the present invention. Absent.
[0029]
【The invention's effect】
In the pulverized coal combustor according to the first aspect of the present invention, the spiral rifle plate is provided on the inner surface of the final straight pipe portion of the pulverized coal pipe for guiding the pulverized coal to the burner, and the spiral curved surface of the rifle plate is Since it is formed on the spiral surface opposite to the spiral drift of the pulverized coal mixture conveyed in the pulverized coal pipe, the spiral pulverized coal drift generated at the bent portion in the pulverized coal pipe, By colliding with a rifle plate that is formed on a spiral surface opposite to the same drift and that overhangs the pulverized coal pipe so as to confront the same pulverized coal drift, this is canceled and the flow of the pulverized coal is changed to a uniform distribution flow. was adjusted so that a steady stream, which can be suitably performed, for example, rectification, etc. in the wake position, optimizes the pulverized coal density distribution in an extremely simple configuration, the low NO _X reduction with stable ignition It has been achieved.
[0030]
Further, according to the invention of claim 2, the final plurality of fins on the inner surface of the straight tube portion of the pulverized coal pipe for guiding the pulverized coal to the burner to array on a spiral streamline, the sequence is the sequence of the fin since spiral streamlines in form constitute a pulverized coal combustor and arranged to symmetrically flow lines are formed for any direction around counterclockwise or right, the fins The spiral streamlines forming the fins in the entire array are arranged so that the streamlines are symmetrically formed in either the counterclockwise direction or the clockwise direction, so that bending in the pulverized coal pipe Spiral pulverized coal drift generated in a part or the like is caused to collide with either the front or back surface of the fin regardless of whether the direction of the drift is the same direction as the spiral arrangement direction of the fin or the opposite direction. This cancels out the pulverized coal drift and creates a uniform flow. For example, instead of the steady flow of suitably performing rectifying action such optimizes the pulverized coal concentration distribution, in which it was possible to achieve low NO _X reduction with stable ignition.
Further, according to the invention of claim 3, in the invention of claim 1 or 2, the pulverized coal pipe is disposed downstream of the spiral rifle plate or the plurality of fins arranged on the spiral streamline. Since the pulverized coal combustor is configured by arranging a core for separating the flow of the pulverized coal in the central part of the pulverized coal pipe upstream of the nozzle portion, the helical rifle plate or the spiral The flow of pulverized coal that has been distributed in a uniform manner by canceling the spiral drift by a plurality of fins arranged on the streamline of the certainly preferred shades separation is performed, in which it was possible to achieve low NO _X reduction with stable ignition.
[Brief description of the drawings]
FIG. 1 is a schematic view of a pulverized coal combustor according to a first embodiment of the present invention.
FIG. 2 is a view taken along the line II-II in FIG.
FIG. 3 is a schematic view of a pulverized coal combustor according to a second embodiment of the present invention.
4 is a view taken along the line IV-IV in FIG. 3;
FIG. 5 is a view taken along the line VV in FIG. 3;
FIG. 6 is a schematic view of a conventional pulverized coal combustor.
[Explanation of symbols]
1 Pulverized coal transport pipe 2 Bent part 3 Kicker 4 Core 4
5 Central distribution 6 Peripheral distribution 7 Rifle plate 8 Pulverized coal mixture 9 Rectifier fin

Claims (3)

A spiral rifle plate is provided on the inner surface of the final straight pipe portion of the pulverized coal pipe that guides the pulverized coal to the burner, and the spiral curved surface of the rifle plate is a spiral shape of the pulverized coal mixture conveyed in the pulverized coal pipe. A pulverized coal combustor characterized by being formed on a spiral surface opposite to the drift . The final plurality of fins on the inner surface of the straight tube portion of the pulverized coal pipe for guiding the pulverized coal to the burner to array on a spiral streamline, the same sequence spiral streamlines counterclockwise to form an array of the fin Alternatively , the pulverized coal combustor is arranged so that streamlines are formed symmetrically in any direction clockwise . The flow of the pulverized coal is separated into the central part of the pulverized coal pipe downstream of the spiral rifle plate or the plurality of fins arranged on the spiral streamline and upstream of the nozzle part of the pulverized coal pipe The pulverized coal combustor according to claim 1 or 2, wherein a child is arranged.

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