JPH09264525A - Fine powder coal separator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a uniform flow speed distribution by a method wherein an outer diameter of a rich or lean separator at an axial center part of a fine powder coal pipe is a frustoconical shape with its flowing-in side being smaller than a flowing-out side, an outer diameter at the flowing-out part as well as a flowing-in side diameter and a flowing-out side diameter of a cut slit passing through an axial center line are made to have a rate of a specified range with the inner diameter of the fine powder coal pipe. SOLUTION: Fine powder coal mixture gas 02 is fed to a rich or lean separator 13 together with primary air. In this case, a slant angle θ of the frustoconical shape of the separator 13 is 60 deg. to 90 deg., an inner diameter of the fine powder coal pipe 05 is defined as D, a diameter d1 of a front flow side of a hollow recess slit is set to (1/10.5) D to (1/20.5) D, a diameter d2 at the rear stream side is set to (1/5.5) D to (1/10.5) D and an outer diameter d3 of the rich or lean separator 13 is set to (1/1.55) D to (1/3.5) D, thereby mixture gas at an outer side having a high fine powder coal concentration and a low fine powder coal concentration at a central part is formed in the fine powder pipe 05. With such an arrangement as above, it is possible to eliminate staying of gas caused by eddy flow which may easily be generated at a wall surface of the rear-side flow of the rich-lean separator 13 and to make a uniform flow speed distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverized coal separator device applied to a pulverized coal burning burner for industrial and commercial boilers.

[0002]

2. Description of the Related Art A conventional pulverized coal separator device for a pulverized coal burner will be described with reference to FIGS. FIG. 7 is a cross-sectional view of a conventional device, FIG. 8 is a front view thereof, and a view taken along the line DD. In both figures, 01 is a pulverized coal conveying pipe, 02 is a pulverized coal mixture, 03 is a distributor, 04 is a burner, 05 is a pulverized coal pipe, 06 is a conc burner, 07 is a weak burner, 08
Is secondary air, 09 is an air box, 10 is a pulverized coal nozzle, 1
Reference numeral 1 indicates a secondary air nozzle.

In the above apparatus, the burner 04 is NOx.
In order to reduce the above, the burner burner 07 having a high pulverized coal concentration and the weak burner 07 having a low pulverized coal concentration are configured as one set. In addition, conc burner 06 and weak burner 0
7 are both composed of a pulverized coal pipe 05 arranged in the center, an air wind box 09 surrounding the periphery thereof with a prism, a prismatic pulverized coal nozzle 10 connected to an outlet portion, and a secondary air nozzle 11.

In the apparatus having such a structure, the pulverized coal mixture 02, which is conveyed together with the primary air through the pulverized coal conveying pipe 01, is distributed and supplied to the conc burner 06 and the weak burner 07 by the action of the distributor 03. Secondary air 08 also injected through the secondary air nozzle 11 after being injected into the furnace through the pulverized coal pipe 05 and the pulverized coal nozzle 10.
Mixes with, diffuses and burns.

[0005]

The above-mentioned conventional pulverized coal burning burner has the following problems.

(1) In order to reduce NOx and stabilize ignition, as described above, the conver burner 06 is used to add a shade to the fuel.
The combination of the weak burner 07 and the weak burner 07 is optimal, but this increases the burner panel height, reduces the service life, and increases the number of dampers, which complicates the overall structure of the burner 04.

(2) The structure of the distributor 03 for adjusting the density of the pulverized coal mixture 02 is complicated.

(3) Manufactured according to the above items (1) and (2),
It becomes extremely complicated in control and maintenance, and also contributes to cost increase.

[0009]

The present invention provides the following means in order to solve such a problem.

(1) The pulverized coal burner is provided at the axial center of the pulverized coal pipe, the outside diameter of which is smaller than the outside diameter (d ₃ ) of the inflow side, and the tip of the inflow side is approximately 90 °. The cross-sectional shape gradually expands along the flow in a frustoconical shape, then becomes parallel to the flow direction, then ends in a plane perpendicular to the axis line, becomes the outflow side outer diameter (d ₃ ), and the axis line There is a notch slit that penetrates in the front and back, and the dimensions of the notch slit are the inlet side diameter (d ₁ ), the outlet side diameter (d ₂ ), and the inner diameter of the pulverized coal pipe (D ), D
₁ = (1 / √ (10)) D to (1 / √ (20)) D, d
₂ = (1 / √ (5)) D to (1 / √ (10)) D, d ₃
= (1 / √ (1.5)) D to (1 / √ (3)) D in a range, the pulverized coal separator device comprising a density separator.

(2) The pulverized coal separator device according to the above (1), wherein the concentration separator is movable along a rail provided in the axial direction inside the pulverized coal pipe.

According to the present invention, in the above-mentioned means (1), the region of the pulverized coal mixture flowing in the pulverized coal pipe that mainly contributes to ignition is the fine powder taken into the circulation on the inner surface of the pulverized coal nozzle. It is a coal flow. The pulverized coal mixture that blows through the central part spreads the flame later than this. By incorporating a density separator at the tip of the pulverized coal pipe, the pulverized coal in the pulverized coal mixture flowing through the pulverized coal pipe collides with the concentration separator installed in the center to give an inertial force to the pulverized coal. Collected on the inner circumferential surface of the pipe, the pulverized coal concentration is high outside the pulverized coal pipe and low in the central side. That is, the same operation as the conventional conc burner and weak burner is performed.

Further, a hollow notch slit is provided in the shaft center of the density separator, and the dimensions d ₁ , d ₂ and d ₃ of the slit are within a range where the density separation effect is enhanced with respect to the pulverized coal inner diameter D. Due to the dimensions, a part of the pulverized coal flow is guided, the central part becomes lighter, the peripheral part has a higher concentration, the stagnation due to vortex flow that tends to occur on the side wall surface behind the density separator is eliminated, and a uniform flow velocity distribution is achieved. It forms and promotes the light and shade separation effect.

Further, by forming the pulverized coal pipe and the concentration separator into a round structure, the pulverized coal mixture can be uniformly separated in density.
Blowing from the pulverized coal nozzle into the boiler is even in the circumferential direction, and stable supply is possible. Furthermore, the pulverized coal mixture after the pulverized coal pipe bend outlet has a strong swirl flow, but if a kicker block or the like is installed at the bend outlet, the swirling force is alleviated, and a more uniform pulverized coal flow is produced in the density separator. Can lead to.

In the means of (2), since the density separator can be moved along the rails before and after the axis of the pulverized coal pipe, the position is adjusted according to the load of the furnace, and the fine powder is placed at the optimum position. The coal flow can be guided to the burner, and the effect in the above (1) is further enhanced.

[0016]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1 is a sectional view of a central portion of a pulverized coal separator device according to an embodiment of the present invention, FIG. 2 is an AA sectional view in FIG. 1, and FIG. 3 is a BB sectional view in FIG. In these drawings, the same members as those of the structure of the conventional pulverized coal separator device are denoted by the same reference numerals, and the detailed description thereof will be omitted and the description will be given as it is, but the characterizing portion of the present invention is the reference numeral 12.
15 to 15, which will be described in detail below.

In these figures, 12 is a kicker block provided on the pulverized coal pipe 05, 13 is a density separator, 14 is a moving rail, and 15 is a position adjuster.
3 is movable back and forth along the moving rail 14,
It is operated by the position adjuster 15.

In the pulverized coal separator device having the above characteristics, the pulverized coal mixture carried by the primary air is 0
No. 2 has a strong swirl flow in the bend part of the pulverized coal pipe 05, and the pulverized coal flow is densely gathered in the lateral part (upper part when vertically upwardly introduced) by the centrifugal force, but in the lateral part of the bend outlet (subject to centrifugal force). The kicking block 12 arranged in the direction) relieves the swirling force, disperses the swirling force again, and the pulverized coal concentration is brought to a substantially uniform state, and is guided to the concentration separator 13.

The pulverized coal mixture 02 is acted by the density separator 13 (the pulverized coal is densely gathered on the inner peripheral surface of the pulverized coal pipe 05 due to the inertial force), so that the pulverized coal concentration in the pulverized coal pipe 05 is outward. High air-fuel mixture, and air-fuel mixture having a low pulverized coal concentration in the center side, respectively, and ejected into the boiler (not shown) via the pulverized coal nozzle 10 for stable ignition, flame holding and low NOx.
Burn.

To adjust the pulverized coal concentration imbalance in the vicinity of the pulverized coal nozzle 10 caused by a change in coal type, load change, etc., the position adjuster 15 is operated to move the density separator 13 on the moving rail 14 along this rail. Move back and forth to guide to the optimum position.

Further, in order to find the optimum density separation and pressure loss of the pulverized coal separator device, the ratio of the height (h) of the kicker block 12 to the pulverized coal pipe diameter (D) or the density separator 13 is used.
The combination of the hollow diameters (d ₁ ) and (d ₂ ) and the inclination angle (θ) are adjusted.

FIGS. 4 and 5 are views for explaining the operation and effect of the pulverized coal separator device according to the embodiment of the present invention. FIG. 4 is a sectional view of the round pulverized coal separator device, and FIG. It is the CC sectional view. In both figures, D is the diameter of the pulverized coal pipe 05, h is the height of the kicker block 12, θ is the inclination angle of the density separator 13, d ₁ and d ₂ are the diameters of the hollow notch slits on the upstream side, and the rear. Shows the diameter on the flow side, and d
₃ indicates the outer diameter of the density separator 13.

In the pulverized coal separator device as described above, the relationship showing good values for density separation and pressure loss of the pulverized coal mixture 02 is as follows.

(1) The height h of the kicker block is; h =
With 0.2D to 0.3D, h = 0.24D is preferable.

(2) The inclination angle θ of the density separator is; θ = 60
From 90 ° to 90 °, θ = 90 ° is preferred.

(3) The diameter d ₁ of the hollow notch slit on the upstream side is; d ₁ = (1 / √ (10)) D to (1 / √ (2
0)) D, and d ₁ = (1 / √ (20)) D is preferable.

(4) The diameter d ₂ on the wake side of the hollow notch slit is; d ₂ = (1 / √ (5)) D to (1 / √ (1
0)) D, and d ₂ = (1 / √ (5)) D is preferable.

(5) The outer diameter d ₃ of the density separator is; d ₃ =
From (1 / √ (1.5)) D to (1 / √ (3)) D, d ₃
= (1 / √ (2)) D is preferable.

Next, the state of concentration distribution of the pulverized coal measured by conducting experiments by varying the size of the density separator 13 will be described with reference to FIG. FIG. 6A is a diagram showing the dimensional relationship of the separator device, FIG. 6B is a diagram in which the pulverized coal concentration distribution from the center of the nozzle to the end is measured by experimenting with the device of FIG. , (C) are explanatory views of the symbols in (b), and there are three cases, respectively,
The dimensions of d ₁ , d ₂ and d ₃ are changed. In addition, in the above-mentioned experiment, it is a test result performed with θ = 90 °, pulverized coal particle size = 200 mesh (75 micron) passage rate 85%, and pulverized coal flow rate = 20 to 26 m / s.

In case (a), d ₁ = (1 / √
(15)) D, d ₂ = (1 / √ (3)) D, d ₃ = (1
/√(1.5)) D, as indicated by the square symbol,
The density is 1.1 although there is some difference in lightness between the center and the periphery.
Since it is within 5 / 1.4, the effect of separation of light and shade cannot be expected so much. In addition, the density is 1.0 as a standard, the right direction is large density,
The left direction indicates pale.

(A) In the case, d ₁ = (1 / √
(25)) D, d ₂ = (1 / √ (7)) D, d ₃ = (1
In the case of / √ (3)) D, the concentration in the peripheral portion tends to be high as indicated by the black circle symbol, but in the central portion, the standard is 1.0, and the degree of separation is somewhat insufficient. .

(C) In the case, d ₁ = (1 / √
(20)) D, d ₂ = (1 / √ (5)) D, d ₃ = (1
In the case of / √ (2)) D, as indicated by a white circle, the density was extremely light at the center and increased as the distance to the periphery was increased, and an ideal separation effect was obtained.

The results in the above case are the best,
Based on the result of this experiment, the preferable values as described in the above items (1) to (5) were obtained.

Regarding the movement of the density separator 13 in the direction of the burner, when the density separation unit 13 is brought closer to the burner side, the density separation is generally
It will improve, but there is a concern that it will burn out due to the flame. On the other hand, if the distance is increased, the effect of separating light and shade tends to decrease. Therefore, it is preferable to adjust the amount of loading and unloading according to the load of the furnace.

In the embodiment described above, the density separator 13 corresponding to the conventional distributor 03 is replaced with the pulverized coal pipe 05.
It has a structure in which the conventional conc burner 06 and the weak burner 07 are integrated, and the kicker block 12 has a surface inclined at the bend direction by changing the direction horizontally at the bend portion of the pulverized coal pipe 05. Further, on the further downstream side, a cross-sectional shape is widened in the flow direction, and thereafter, a horizontal low-level separator 13 which is horizontal and has a hollow cutout slit in the center of the shaft center is provided. Further, it is characterized by a round type pulverized coal separator device in which a circular pulverized coal nozzle 10 is arranged at the downstream end.

The above-described embodiment has the following actions and effects.

(1) In the pulverized coal mixture 02 flowing in the pulverized coal pipe 05, the region mainly contributing to ignition is the pulverized coal nozzle 1
0 It is a pulverized coal flow that is taken into circulation on the inner surface. The pulverized coal mixture 02 that blows through the central portion propagates the flame later than this. By incorporating the concentration separator 13 at the tip of the pulverized coal pipe 05, the pulverized coal in the pulverized coal mixture 02 passing through the pulverized coal pipe 05 collides with the concentration separator 13 installed in the center, and the inertial force is increased. The pulverized coal is given and collected on the inner peripheral surface of the pulverized coal pipe 05. The pulverized coal concentration is high on the outside of the pulverized coal pipe 05 and low on the center side.

That is, the same operation as the conventional conc burner 06 and weak burner 07 is performed. Further, a hollow notch slit is provided on the axis of the concentration separator 13 to guide a part of the pulverized coal flow, eliminating stagnation due to eddy currents that are likely to occur on the side wall surface of the concentration separator 13 wake, and uniform flow velocity distribution. To promote the separation effect of light and shade.

(2) Due to the round structure, the pulverized coal mixture 02 can be uniformly separated in density, and the pulverized coal nozzle 10 can be blown into the boiler in a uniform manner in the circumferential direction.

(3) Pulverized coal pipe 05 The pulverized coal mixture 02 after the bend exit has a strong swirling flow, but the swirling force is alleviated by installing the kicker block 12, and a uniform pulverized coal flow is separated into a density separator. Lead to 13.

(4) Dark and light separator 1 for pulverized coal pipe 05
By specifying the dimension of 3, an ideal concentration distribution can be obtained.

[0042]

As described above in detail, according to the present invention, a density separator is provided at the pulverized coal pipe shaft center, a notch slit is provided at the center of the axis of the density separator, and the density separator is provided. Since the outer shape and the size of the notch slit are specified within a predetermined range and the concentration separator is configured to be movable in the axial direction of the pulverized coal pipe, the following effects are obtained.

(1) The conc burner and the weak burner are integrated, the number of burners is reduced, the separator is compact and the entire burner is simplified, and the cost is reduced.

(2) Since the density separation device is provided instead of the separator, the separator is simplified and the pressure loss is reduced.

(3) By using the pulverized coal separator device having the round structure, the pulverized coal mixture can be blown into the boiler evenly in the circumferential direction, so that the local increase in heat load can be eliminated. .

(4) The density separation of the pulverized coal can be performed with an ideal distribution by providing the density separation device with a predetermined size and providing the hollow notch slits.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pulverized coal separator device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

3 is a sectional view taken along line BB in FIG.

FIG. 4 is a shape explanatory view of a pulverized coal separator device according to an embodiment of the present invention, which is a cross-sectional view showing the shape of a density separator.

FIG. 5 is a sectional view taken along the line CC in FIG.

FIG. 6 shows an experimental result of a pulverized coal separator device according to an embodiment of the present invention, (a) is a diagram showing a shape of the separator device, (b) is an experimental result of the device of (a), The figure which shows a light and shade distribution condition, (c) shows the explanatory drawing of a symbol, respectively.

FIG. 7 shows a cross-sectional view of a conventional pulverized coal separator device.

FIG. 8 shows a view taken along the line D-D in FIG. 7.

[Explanation of symbols]

 02 Pulverized coal mixture gas 05 Pulverized coal pipe 10 Pulverized coal nozzle 12 Kicker block 13 Concentration and concentration separator 14 Moving rail 15 Position adjuster

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Suzuki 5-717-1, Fukahori-cho, Nagasaki City, Nagasaki Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor, Koji Yamada 1-1, Atsunoura-cho, Nagasaki-shi Mitsubishi Heavy Industries Stock Company Nagasaki Shipyard (72) Inventor Takahiro Isoda 1-1 No. Agatsunouramachi, Nagasaki City Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard (72) Inventor Takehiko Shirahata 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industries Co., Ltd. Within

Claims (2)

[Claims] 1. A head provided at an axial center of a pulverized coal pipe inside a pulverized coal burner, the outer diameter of which is smaller than the outer diameter (d ₃ ) of the inflow side, and the tip of which is approximately 90 ° on the inflow side. The cross-sectional shape gradually expands along the flow in the shape of a cone, and then ends in a plane perpendicular to the rear axis that is parallel to the flow direction, becomes the outer diameter (d ₃ ) of the outflow side, and is centered around that axis. It has a notch slit penetrating in the front and rear, and the dimensions of the notch slit are the diameter on the inflow side (d ₁ ) and the diameter on the outflow side (d ₂ ).
And the inner diameter of the pulverized coal pipe is (D), d ₁ = (1
/ √ (10)) D to (1 / √ (20)) D, d ₂ = (1
/ √ (5)) D to (1 / √ (10)) D, d ₃ = (1 /
A pulverized coal separator device comprising a density separator in the range of √ (1.5)) D to (1 / √ (3)) D. 2. The pulverized coal separator device according to claim 1, wherein the density separator is movable along a rail provided in the axial direction inside the pulverized coal pipe.