JP2019018926A - Powder supply device - Google Patents

Abstract

To provide a powder supply device capable of quantitatively feeding a raw material stably even in a situation in which a discharge destination side is negative in pressure with respect to a hopper side.SOLUTION: A powder supply device drives a chain conveyor 1 to push and move powder deposited on an intermediate partition plate 3 with a scraper 1D on a going-up side UP, and then make the powder fall on a bottom surface part 2A from the intermediate partition plate 3 after passing the position of a cut gate 4. A limiting plate 10 is provided downstream of the cut gate 4, and then the powder being fed by the cut gate 4 and pushed by the scraper 1D to move is restricted from above and below the intermediate partition plate 3 and limiting plate 10 and also restricted from the left and right by left and right side walls 2C of a casing 2, thereby forming a layer of a pressure seal with the powder loaded relatively by weighting like compacting from the four directions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a powder supply apparatus for cutting and supplying powder such as coal supplied from a hopper at a target supply amount. In particular, the present invention relates to a powder supply apparatus suitable as a coal feeder for supplying coal to a coal pulverizer in a blast furnace PCI facility (pulverized coal injection facility).

In normal PCI equipment, a closed chain conveyor is used as a coal feeder for supplying coal to a coal pulverization mill (coal pulverizer). In the coal feeder, a coal hopper is attached to a coal supply port, and a discharge port is connected to the coal pulverizer. The amount of coal cut by the coal feeder is controlled by the speed of the chain conveyor.
The inventors confirmed the above coal feeder, and when the pressure difference between the coal hopper and the coal crushing mill was as small as about 0.5 kPa, there was no problem that the quantitative cutout amount of coal fluctuated. . However, depending on the operating conditions, it may be assumed that the pressure difference between the coal hopper and the coal crushing mill is 10 kPa or more. Under such circumstances, the conventional closed chain conveyor causes the coal to be hopper side by negative pressure. It was found that the amount of cut out varied.

Here, there is a screw conveyor as a powder supply apparatus capable of quantitative cutting even if there is a pressure difference between the supply port and the discharge port. However, the screw conveyor has a problem that the length of the machine is 6 m or more and a conveyance capacity of 100 t / h is necessary or a material having high adhesiveness is not suitable.
Moreover, there exists a belt conveyor apparatus for powder conveyance of patent document 1 as a powder supply apparatus which has a pressure difference and can be cut out quantitatively. In this belt conveyor device for powder conveyance, it can be applied to a pressure difference where the hopper is negative pressure and the discharge destination is atmospheric pressure, but the discharge destination side is different from the hopper side as in the PCI equipment as described above. If the pressure difference is negative, it may not be adopted.

Japanese Patent Laid-Open No. 9-142665

  The present invention pays attention to the above points, and provides a powder supply apparatus that can stably and quantitatively cut out raw materials even in a situation where the discharge side is negative with respect to the hopper side. For the purpose.

In order to solve the problems, a powder supply apparatus according to one aspect of the present invention includes an endless annular chain and a chain conveyor including a plurality of scrapers attached to the chain at predetermined intervals along the moving direction of the chain. A closed casing that houses the chain conveyor, the bottom surface portion extends along the downward side of the chain conveyor, and the ceiling surface portion extends along the upward side of the chain conveyor, and the ceiling An opening formed in the surface portion, the powder supply port to which a lower portion of a hopper for supplying powder is connected, and at least a position facing the powder supply port from the lower side, the upward side And a partition plate extending along the upward side between the upward side and the downward side, and extending downward from the ceiling surface portion toward the intermediate partition plate to determine the cutting height of the raw material And Ttogeto, a powder supply device and a open powder outlet on the bottom portion of the casing,
The intermediate partition plate has an extended portion that extends more than the cutting height toward the downstream side in the moving direction on the upward side from the position of the cut gate in a top view, and faces the extended portion. At a possible position, a limit plate is provided on the downstream side of the lower end portion of the cut gate and extends toward the downstream side in the upward movement direction, and the upward side of the limit plate The length toward the downstream side in the moving direction is a length in the range of the cutout height or more and less than twice the cutout height.

  According to one aspect of the present invention, the powder that is cut out by the cut gate, pushed by the scraper and moved, and still located on the intermediate partition plate (on the upward side) is the intermediate partition plate, the restriction By being restrained from the four sides by the left and right side walls of the plate and casing, a pressure seal layer in a consolidated state is continuously formed. As a result, according to one aspect of the present invention, it is possible to stably and quantitatively cut out a raw material even in a situation where the discharge destination side has a negative pressure higher than a predetermined value with respect to the hopper side.

It is a conceptual diagram explaining the powder supply apparatus which concerns on embodiment based on this invention. It is a typical sectional view in a restricting board position concerning an embodiment based on the present invention. It is a conceptual diagram explaining the example of the length of a restriction | limiting board. It is a figure which shows the relationship between a restriction | limiting board and a partition plate. It is a figure which illustrates the limiting plate whose inclination is movable. It is a conceptual diagram explaining the conventional problem. It is a conceptual diagram explaining the effect of the powder supply apparatus which concerns on embodiment based on this invention.

Next, embodiments of the present invention will be described with reference to the drawings.
The embodiment described below exemplifies a configuration for embodying the technical idea of the present invention. The technical idea of the present invention is such that the material, shape, structure, etc. of the component parts are as follows. Not specified. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

In the present embodiment, a powder supply device as a coal feeder for supplying coal to a coal pulverizer in a blast furnace PCI facility (pulverized coal injection facility) will be described as an example. That is, the case where powder consists of coal is illustrated. However, the powder applicable to the powder supply apparatus of the present invention is not limited to coal.
The PCI equipment includes, for example, a coal hopper, a powder supply device (coal feeder), a coal pulverizer, a coal bottle, and a blowing tank. Then, coal is supplied from the raw coal bunker to the coal hopper, and the coal stored in the coal hopper is quantitatively cut out from a coal pulverizer such as a coal pulverization mill by the powder supply device. The powder supply device crushes coal in a dry atmosphere such as hot air. The crushed coal is further sieved with a filter or the like to become pulverized coal having a predetermined particle size or less, and is intermittently supplied to the coal bin. The pulverized coal stored in the coal bottle is supplied to the blowing tank, and the pulverized coal in the blowing tank is blown into the blast furnace from the tuyere.

(Constitution)
As shown in FIG. 1, the powder supply apparatus according to the present embodiment includes a chain conveyor 1, a sealed casing 2 that houses the chain conveyor 1, an intermediate partition plate 3, and a cut gate 4.
The chain conveyor 1 is spanned in an endless ring between two endless annular chains 1A and a pair of sprockets 1B and 1C, and the drive sprocket 1B is driven to drive the chain 1A. A plurality of scrapers 1D are attached between the pair of chains 1A. The scraper 1D is composed of a rectangular plate material, and is disposed with its longitudinal direction directed in a direction intersecting the moving direction of the chain 1A, for example, a direction orthogonal thereto. The height of the scraper 1D is set to be equivalent to the cutting height H of the raw material (powder). A plurality of scrapers 1D are provided at predetermined intervals along the moving direction of the chain 1A.

The casing 2 that houses the chain conveyor 1 is disposed along the chain conveyor 1 to form a sealed space having a rectangular cross section. That is, as shown in FIGS. 1 and 2, the casing 2 has a rectangular cross section from the bottom surface portion 2A, the ceiling surface portion 2B, and the left and right side walls 2C.
The bottom surface portion 2A extends along the downward side LO of the chain conveyor 1. A powder discharge port 6 for discharging coal is formed at a position downstream of the downward LO in the bottom surface portion 2A.

  The bottom portion 2A is set so that the portion facing the downward side LO of the chain conveyor 1 from the lower side faces the lower end of the scraper 1D located on the downward side LO with a predetermined gap. . As a result, the coal that has moved to the upstream side position of the downward LO in the bottom surface portion 2A can be moved by being pushed toward the powder discharge port 6 by the scraper 1D of the downward LO.

  The ceiling surface portion 2B extends along the upward side UP of the chain conveyor 1. The ceiling surface portion 2B is set at a height close to the scraper 1D. In the middle of the extending direction of the ceiling surface portion 2B, for example, a rectangular powder supply port 5 that connects the lower portion of the coal hopper 7 to supply coal is opened. A coal hopper 7 is connected to the powder supply port 5 so that coal can be supplied from the coal hopper 7.

  Here, in the ceiling surface portion 2B, the ceiling is longer than the raw material cutting height H by a predetermined length from the position of the powder supply port 5 (position of the cut gate 4) toward the upward movement direction UP. By being high, the coal supplied from the coal hopper 7 is easily transferred when it is cut out by the cut gate 4 and pushed by the scraper 1D of the upward UP. That is, it has a function of preventing an increase in conveyor driving force. The space portion formed with the high ceiling is referred to as a buffer space S. The buffer space S is also used as a space for repair work on the partition plate 3 when the chain conveyor 1 or the scraper 1D is damaged through a manhole (not shown) provided in the ceiling surface portion 2B. .

The left and right side walls 2C are arranged close to the left and right ends of the scraper 1D.
The cut gate 4 is a plate member that is located on the downstream side of the upward UP from the powder supply port 5 and protrudes downward from the ceiling surface portion 2B at the buffer space S position. The distance between the cut gate 4 and the lower partition plate 3 is set to the cutting height H of the raw material. The position of the cut gate 4 does not need to be in contact with the end of the powder supply port 5 and may be a position where at least a part of the buffer space S is formed behind.

  The middle partition plate 3 exists at least at a position facing the powder supply port 5 from below, and extends along the upward side UP between the upward side UP and the downward side LO. The left and right sides of the middle partition plate 3 are attached to the left and right side walls 2C of the casing 2. The upper surface of the intermediate partition plate 3 is set so as to face the lower end surface of the upward UP scraper 1D with a predetermined gap. As a result, the coal supplied from the coal hopper 7 is deposited on the intermediate partition plate 3 and pushed by the upward UP scraper 1D, so that the coal moves along the intermediate partition plate 3. .

  The intermediate partition plate 3 extends in the upstream side and the downstream side in the moving direction of the upward side UP from the position of the powder supply port 5 in a top view, and the coal from the coal hopper 7 is more reliably supplied to the intermediate partition plate 3. 3 is put on. In particular, the middle partition plate 3 extends more than the raw material cutting height H toward the upstream side of the upstream side UP from the position of the cut gate 4 in a top view. The extending portion is referred to as an extending portion 3A. The extending portion 3A is set to a length that is longer than the limit plate 10 described later. However, the length of the extending portion 3A is shorter than the length of the buffer space S.

In addition, the powder supply apparatus of the present embodiment includes a limiting plate 10 on the downstream side of the cut gate 4.
The limit plate 10 is located at the position of the buffer space S in the top view so as to be opposed to the extending portion 3A, and is provided with one end portion behind the lower end portion of the cut gate 4 so It is a board extending toward. The restriction plate 10 is preferably supported by the ceiling surface portion 2B in order to receive an upward load from coal. Since the limiting plate 10 is supported by the ceiling surface portion 2 </ b> B, there may be a gap between the limiting plate 10 and the cut gate 4. The height of one end of the limiting plate 10 (the end on the cut gate 4 side) is the same height as the lower end of the cut gate 4. It may be set to be slightly higher.

Here, the gap in the present specification is preferably a gap that is equal to or less than the average particle diameter of the target coal.
The length of the restricting plate 10 toward the downstream side in the moving direction of the upward side UP is set, for example, within a range that is not less than twice the cut height H and less than twice the cut height H.
The length of the limiting plate 10 is preferably equal to or longer than the length L defined by the repose angle θ of the target coal, as shown in FIG. That is, the length L (= H / tan θ) or more at which the angle of intersection with the diagonal straight partition plate 3 drawn from the cut gate 4 toward the partition plate 3 is the repose angle θ is preferable. By setting the extending portion 3A and the restriction plate 10 to be equal to or longer than the length L defined by the angle of repose θ, the coal is more reliably partitioned when the coal from the coal hopper 7 falls and rests on the intermediate partition plate 3. While being placed on the plate 3, it becomes possible to form a layer of the coal portion that is more reliably consolidated to form a pressure seal.

The length of the pressure seal layer is determined based on the properties of the target coal (powder) and the upper limit value of the pressure difference assumed in the target powder supply device. However, if it is determined from an experiment or a theoretical formula, the target pressure seal layer can be secured if the cutting height is H or more.
However, if the pressure seal layer by providing the limiting plate 10 is too long, it is necessary to increase the driving force of the conveyor accordingly, so it is defined by less than twice the cutting height H or the repose angle θ. The length is preferably less than twice the length L.

Here, the conveyance speed of the chain conveyor 1 assumed in the present embodiment is, for example, about 50 to 150 mm / sec. If the conveyance speed is within this range, the length of the limit plate 10 is not significantly affected. .
As shown in FIG. 4, the limit plate 10 is larger than 0 degree with respect to the middle partition plate 3 and 20 ° so that the distance from the middle partition plate 3 increases toward the downstream side in the moving direction of the upward side UP. It is preferable to have a gradient of less than or equal to degrees. When the upper surface of the middle partition plate 3 is horizontal, the lower surface of the limiting plate 10 is preferably provided with an elevation angle greater than 0 degrees and 20 degrees or less so as to be positioned upward as it goes away from the cut gate 4. .

  Along the extending direction, the distance between the middle partition plate 3 and the limiting plate 10 may be set to be equal, but by setting a slight gradient as described above, it is constrained to be consolidated. It becomes easy to push the coal with the scraper 1D. The distance between the intermediate partition plate 3 and the limiting plate 10 may be set so as to decrease toward the downstream, but since the driving force of the chain conveyor 1 increases accordingly, a durable chain corresponding thereto It is necessary to employ the conveyor 1.

In addition, the limiting plate 10 may be configured to be movable up and down around the predetermined rotation shaft 11 around the cut gate 4 side as shown in FIG. In this case, according to the properties of the target coal, it is possible to appropriately set a gradient in which the balance between the compacted state by the restriction plate 10 and the extrusion pressure by the scraper 1D is optimal.
In FIG. 5, since the rotation center is set above the limit plate 10, the end of the limit plate 10 on the cut gate 4 side is warped upward in a bowl shape.

(Operation other)
The powder supply device drives the chain conveyor 1 to move the coal supplied from the powder supply port 5 and deposited on the intermediate partition plate 3 in order by the upward UP scraper 1D to move the cut gate 4 position. After passing through the cut gate 4 position by adjusting the cutout height of the coal by passing, it is dropped from the downstream end portion in the longitudinal direction of the intermediate partition plate 3 to the bottom surface portion 2A, and the coal dropped on the bottom surface portion 2A is It is pushed by the scraper 1D of the downward LO and moved toward the powder discharge port 6.

Here, the amount of coal discharged from the powder supply device (coal feeder) (coal feed amount) is adjusted at the speed of the chain conveyor 1 to obtain a stable coal pulverization amount in the coal pulverizer. The speed of the chain conveyor 1 of a supply apparatus (coal feeder) is controlled. The control is performed, for example, by controlling the rotational speed of the drive sprocket 1B.
The upstream of the coal feeder is a coal hopper 7 installed under atmospheric pressure, and the downstream is a coal pulverizer in a negative pressure state. And the negative pressure tends to increase as the set coal pulverization amount is set larger. Even if the pressure difference is as large as about 10 kPa, the coal in the casing 2 is ejected to the coal hopper 7 side. It is preferable that the amount of coal cut-out proportional to the speed of the chain conveyor 1 can be controlled so as not to be leveraged.

At the same time, in order to prevent the explosion of coal dust in the coal pulverizer, airtightness is required so that air does not flow into the coal movement passage from the coal hopper 7 to the coal pulverizer.
And when it is a case where the limiting plate 10 like this embodiment is not provided, for example, the pressure in the powder discharge port 6 is a negative pressure state of about -10 kPaG, it is a schematic diagram by the negative pressure. 6, there is a risk that the coal 20 may spill out behind the cut gate 4 so as to be ejected to the sprocket 1B or the bottom surface 2A side. Even if it cuts out, fluctuation | variation generate | occur | produces in the quantity of the coal which falls to 2 A of bottom parts, and there exists a possibility that fluctuation | variation may generate | occur | produce in the supply amount of coal from the powder discharge port 6. FIG.

  On the other hand, in the present embodiment, as shown in FIG. 7, a limiting plate 10 is provided on the downstream side of the cut gate 4 so as to be opposed to the middle partition plate 3 in the vertical direction. The coal moving on the intermediate partition plate 3 is constrained from the upper and lower directions by the intermediate partition plate 3 and the restriction plate 10 and constrained from the left and right by the left and right side walls 2C of the casing 2 so as to be consolidated from four directions. Move while applying relative weight. As a result, the coal located between the middle partition plate 3 and the restriction plate 10 becomes dense, and the coal in this portion is a pressure seal layer (the portion denoted by reference numeral 21 in FIG. 7), and the coal hopper 7 side and the powder. It is formed between the discharge port 6 and coal is prevented from being ejected to the coal hopper 7 side due to negative pressure, and the amount of coal corresponding to the speed of the chain conveyor 1 is stably dropped to the bottom surface portion 2A. Is possible.

As a result, even if the negative pressure on the powder discharge port 6 side increases due to an increase in the coal pulverization amount, a stable amount of coal can be supplied to the coal pulverizer side. That is, in the powder supply apparatus according to the present embodiment, the raw material can be stably quantified and cut out.
In addition, by forming the gradient as described above in which the downstream side becomes higher on the restriction plate 10, even if the coal cut out by the cut gate 4 is restrained by the restriction plate 10 to form a dense coal layer, the chain conveyor 1 The increase in the driving amount can be suppressed to a small level.

DESCRIPTION OF SYMBOLS 1 Chain conveyor 1A Chain 1B, 1C Sprocket 1D Scraper 2 Casing 2A Bottom surface part 2B Ceiling surface part 2C Side wall 3 Middle partition plate 3A Extension part 4 Cut gate 5 Powder supply port 6 Powder discharge port 7 Coal hopper 10 Limit plate LO Below Outbound side Upbound side S Buffer space θ Angle of repose

Claims (4)

A chain conveyor comprising an endless annular chain and a plurality of scrapers attached to the chain at predetermined intervals along the moving direction of the chain;
A closed casing that houses the chain conveyor, the bottom surface portion extends along the downward side of the chain conveyor, and the ceiling surface portion extends along the upward side of the chain conveyor;
A powder supply port connected to a hopper lower part for supplying powder, which is an opening formed in the ceiling surface part;
A partition plate present at least at a position facing the powder supply port from the lower side, and extending along the upward side between the upward side and the downward side;
A cut gate that extends downward from the ceiling surface part toward the partition plate and determines the cutting height of the raw material,
A powder supply device comprising a powder discharge port opened in a bottom surface portion of the casing,
The middle partition plate has an extending portion that extends more than the cut height toward the downstream side in the moving direction on the upward side from the position of the cut gate in a top view,
At a position that can be opposed to the extended portion, a limit plate is provided that extends toward the downstream side in the moving direction on the upward side by disposing one end on the downstream side of the lower end portion of the cut gate,
The length of the restricting plate toward the upstream side in the moving direction on the upward side is a length in a range not less than twice the cut height and less than twice the cut height. .   The restricting plate has a gradient greater than 0 degree and 20 degrees or less with respect to the intermediate partition plate so that the distance from the intermediate partition plate increases as it goes downstream in the upward movement direction. The powder supply apparatus according to claim 1.   3. The powder according to claim 1 or 2, wherein the powder is coal, and the powder discharge port of the casing is connected to a supply port of a coal pulverizer for pulverizing the coal to have a negative pressure. The powder supply apparatus described. A chain conveyor comprising an endless annular chain and a plurality of scrapers attached to the chain at predetermined intervals along the moving direction of the chain;
A closed casing that houses the chain conveyor, the bottom surface portion extends along the downward side of the chain conveyor, and the ceiling surface portion extends along the upward side of the chain conveyor;
A powder supply port connected to a hopper lower part for supplying powder, which is an opening formed in the ceiling surface part;
A partition plate present at least at a position facing the powder supply port from below, and extending along the upward side between the upward side and the downward side;
A cut gate that extends downward from the ceiling surface part toward the partition plate and determines the cutting height of the raw material,
A powder outlet opening in the bottom of the casing,
By driving the chain conveyor, the powder supplied from the powder supply port and deposited on the intermediate partition plate is pushed and moved by the upward scraper and passed through the cut gate position to cut the raw material cut height. After adjusting the thickness and passing through the cut gate position, it is dropped from the middle partition plate to the bottom surface portion, and the powder dropped on the bottom surface portion is pushed by a downward scraper toward the powder discharge port. A powder supply device to be moved,
A restriction plate is provided downstream of the cut gate so as to face the middle partition plate in the vertical direction, and the powder that is cut by the cut gate and pushed and moved by the scraper is moved in the vertical direction by the middle partition plate and the restriction plate. The powder supply device is characterized in that a pressure seal layer is formed by the powder by relatively applying a load that is constrained from the left and right by the left and right side walls of the casing and being consolidated from four directions.

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