JP2013103212A - Vertical pulverizer and coal-fired boiler plant equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical pulverizer which can adjust a flow rate of gas for conveyance, can prevent fall of matter to be pulverized and can adjust primary classification strengthening.SOLUTION: The vertical pulverizer is composed of blocks formed by dividing a throat 42 arranged between a housing 44 and a pulverizing table 2 to two or more along a circumferential direction. The blocks are composed of a combination of: a first block 501 which has two or more throat openings 84 surrounded by an inner ring 70, an outer ring 71 and a throat vane 43; and a second block 502 which has one or more throat openings 84 and one or more closed parts 82 closing the throat openings 84.

Description

  The present invention relates to a vertical pulverizer for pulverizing solids such as coal and a coal fired boiler plant equipped with the same, and more particularly to a throat structure for introducing a carrier gas into the vertical pulverizer.

  In a coal-fired boiler apparatus for thermal power generation that burns pulverized coal as fuel, a vertical crusher is used as a fuel supply apparatus.

FIG. 16 is a schematic configuration diagram illustrating an example of a vertical crusher.
This vertical pulverizer includes a drive unit A that rotationally drives the pulverizing table 2, a pulverizing unit B that pulverizes the coal 60 that is to be pulverized by meshing between the pulverizing table 2 and the pulverizing roller 3 that is a pulverizer, A classifying unit C that is installed at the upper part of the pulverizing unit B and classifies the coal powder to an arbitrary particle size, and a plurality of coal feeding pipes 31 that are connected to a coal-fired boiler device (not shown). It is mainly comprised from the distribution part D to distribute.

 In the figure, 5 is a pressure frame, 6 is a roller bracket, 7 is a roller pivot, 8 is a pressure rod, 9 is a pressure cylinder, 30 is a distributor, 50 is a speed reducer for the grinding table, and 51 is for driving the grinding table. It is a motor.

  Next, the operation of this vertical crusher will be described. As indicated by the arrow, the coal 60 supplied from the coal supply pipe 1 drops on the center of the rotating crushing table 2 and then spirals on the crushing table 2 by the centrifugal force accompanying the rotation of the crushing table 2. The trajectory is drawn and moved to the outer periphery, and is pulverized by being caught between the crushing table 2 and the crushing roller 3.

  On the other hand, the pulverized object conveying gas 61 which also serves as the primary air for combustion is sent to the wind box 41 through the conveying gas duct 40 and introduced into the pulverizing section B from the throat 42 provided around the pulverizing table 2. The

  The pulverized coal powder is mixed with a high-temperature carrier gas 61 at the upper part of the throat 42 to form a solid-gas two-phase flow 62, which is blown upward while being dried. Among the powders blown up, those having a large particle size fall by gravity while being conveyed to the classification unit C, are returned to the pulverization unit B (primary classification), and are pulverized again.

  The particle group that has reached the classification portion C is classified into fine particles 65 having a predetermined particle size or less and coarse particles 64 exceeding the predetermined particle size (secondary classification), and the coarse particles 64 fall into the pulverization portion B and are pulverized again. . On the other hand, the fine particles 65 exiting the classification section C are sent as product fines 66 from the coal feeding pipe 31 to a burner (not shown) of the coal burning boiler device.

  In the case of this example, the classification part C is composed of a fixed fin 11 and a recovery cone 10. A large number of the fixing fins 11 are suspended from the upper surface plate 45 and fixed at an arbitrary angle with respect to the central axis direction of the classification portion C. The recovery cone 10 is provided in a mortar shape below the fixed fin 11.

  In the case of this example, the classifying unit C is composed of a fixed classifier (the fixed fin 11 and the recovery cone 10), but the classifying unit C may be composed of a rotating classifier equipped with a rotating fin.

  FIG. 12 is an enlarged sectional view of a fixed throat in which the throat 42 is fixed to the inner peripheral side of the housing 44. FIG. 13 is an enlarged cross-sectional view of a rotary throat that attaches to the outer peripheral portion of the crushing table 2 and rotates together with the crushing table 2. In FIG. 12, the space between the throat 42 and the crushing table 12 is largely open between FIG. 13 and the space between the throat 42 and the housing 44. However, this is for convenience of explanation, and there is almost no gap in practice. Designed not to be.

 The rotary throat is becoming mainstream in recent years because it can reduce coal falling through the throat 42 and reduce the flow rate of the transport gas 61 through the throat 42.

FIG. 14 is a cross-sectional view taken along the line E-E ′ of FIG.
In the throat 42, for the purpose of strengthening the primary classification, a throat vane 43 (see FIG. 14) inclined at an angle α with respect to the horizontal direction is circumferentially placed in a gap between the inner ring 70 and the outer ring 71 (both see FIG. 12). Many sheets are installed in the direction to give swirling force to the jet gas.

 As described above, the transport gas 61 sent from the transport gas duct 40 is stored in the wind box 41 and is jetted to the upper crushing section B while applying a turning force by the throat vane 43. The inclination angle α of the throat vane 43 is generally set in the range of 30 to 60 degrees. In some cases, the inclination direction of the throat vane 43 is opposite to that shown in FIG.

US Pat. No. 5,549,251 WO2009 / 115828

  If the air flow rate at the throat 42 is too low, coal powder will fall through the throat 42, while if it is too high, the pressure loss will increase. Therefore, setting the air flow rate at the throat 42 is very important.

  If there is a deviation between the initially set flow rate and the appropriate flow rate in the relevant coal type or operating conditions due to changes in the coal type or operating conditions, it is necessary to adjust the air flow rate at the throat 42. Since the ratio of air is determined by the optimum condition in combustion, the air flow rate cannot be adjusted by changing the amount of air.

  Therefore, conventionally, as shown in FIG. 15, the opening area of the throat 42 as a whole is increased or decreased by installing the closing plates 80a and 80b at some openings 84 of the throat 42 or by removing the closing plates 80a and 80b. The air flow rate at the throat 42 was adjusted. The closing plates 80 a and 80 b are attached to the throat 42 by welding or bolts 81. In FIG. 15, the example of attachment with the volt | bolt 81 is shown.

  However, in welding or mounting with bolts 81, the closing plates 80a and 80b are detached due to vibration or wear of the throat 42, and the detached closing plates 80a and 80b are blown away inside by the air flow velocity and collide with the structure in the mill. As a result, the structure is destroyed, or the disengaged closing plates 80a and 80b enter the crushing table 2 and are engaged with the crushing table 2 and the crushing roller 3, so that the crushing table 2 and the crushing roller 3 are destroyed. there is a possibility.

  In particular, in the case of a rotary throat in which the throat 42 rotates together with the pulverizing table 2, the vibration of the pulverizing table 2 is directly transmitted to the throat 42. Therefore, there is a problem that the vibration of the throat 42 is large and the closing plates 80a and 80b are likely to come off.

  An object of the present invention is to provide a vertical pulverizer capable of adjusting the flow rate of a carrier gas and preventing the fall of an object to be crushed and adjusting primary classification, and a coal fired boiler plant equipped with the vertical pulverizer. .

In order to achieve the above object, the first present invention provides:
A housing;
A crushing table rotatably installed inside the housing;
A pulverizer composed of a plurality of pulverization rollers, for example, disposed on the pulverization table;
An annular space that is disposed between the housing and the crushing table and is formed by a cylindrical inner ring, a cylindrical outer ring that is installed outside the inner ring, and the inner ring and the outer ring. A throat consisting of a number of throat vanes that divide the
With a windbox at the bottom of the throat,
By crushing the pulverization table and a pulverizer, an object to be pulverized, such as coal, is pulverized to generate pulverized particles, and the conveying gas supplied to the window box is passed through the throat vane to the outer periphery of the pulverization table. It is intended for a vertical pulverizer that jets out and conveys the pulverized particles upward.

And the first means of the present invention is:
The throat comprises a block divided into a plurality along the circumferential direction,
The block includes a first block having two or more throat openings surrounded by the inner ring, the outer ring, and the throat vane, one or more throat openings, and one or more throat openings. It is characterized in that it is configured by combining two types of blocks, the second block, having a blocking portion for closing the block.

According to a second means of the present invention, in the first means,
A throat constituted by a combination of the first block and the second block is fixed to the pulverizing table side, and the throat rotates with the pulverizing table.

A third means of the present invention is the first or second means,
The ratio of the second block having the blocking portion to the total number of blocks constituting the throat is restricted to ½ or less.

According to a fourth means of the present invention, in any one of the first to third means,
The second blocks having the blocking portion are arranged so as not to be adjacent to each other.

According to a fifth means of the present invention, in any one of the first to fourth means,
The first block and the second block have the same shape and size, and the first block and the second block are interchangeable.

According to a sixth means of the present invention, in any one of the first to fifth means,
The inner ring portion, the outer ring portion, and the throat vane portion of the first block are integrally formed of, for example, a casting, and the inner ring portion, the outer ring portion, and the throat of the second block are integrally formed. The vane portion and the closed portion are formed of a single piece by, for example, casting or the like.

According to a seventh means of the present invention, in any one of the first to sixth means,
The closing portion of the second block is formed so as to close the upper throat opening.

The eighth means of the present invention is any one of the first to seventh means,
The second blocks are arranged uniformly in the throat.

The ninth means of the present invention includes
A vertical crusher;
In a pulverized coal fired boiler plant equipped with a pulverized coal fired boiler device that burns pulverized coal produced by pulverization with the vertical pulverizer,
The vertical crushing device is a vertical crushing device of any one of the first to eighth means.

  The present invention has the above-described configuration, and is a vertical pulverizer capable of adjusting the flow rate of the conveying gas, preventing the object to be pulverized from falling, and adjusting the primary classification enhancement, and a coal-fired boiler equipped with the vertical pulverizer A plant can be provided.

It is a longitudinal cross-sectional view of the throat periphery in the rotary throat which concerns on 1st Embodiment of this invention. It is a top view of the whole throat. It is an enlarged top view of the 1st block which comprises a throat. It is sectional drawing on the FIG. 3A-A 'line. It is an enlarged top view of the 2nd block which comprises a throat. FIG. 5B is a cross-sectional view taken along line B-B ′. It is an enlarged top view which shows the example of a combination of a 1st block and a 2nd block. FIG. 8 is a cross-sectional view taken along the line C-C ′ of FIG. 7. It is an enlarged top view which shows the other example of a combination of a 1st block and a 2nd block. It is an enlarged top view of the 2nd block concerning a 2nd embodiment of the present invention. It is sectional drawing on the FIG. 10D-D 'line. It is a longitudinal cross-sectional view of the throat periphery in a fixed throat. It is a longitudinal cross-sectional view around the throat in the rotary throat. It is sectional drawing on the FIG. 12E-E 'line. It is a longitudinal cross-sectional view around the throat in the conventional structure. It is a schematic block diagram of a vertical mill. It is a distribution diagram of a coal fired boiler plant provided with a vertical crusher concerning an embodiment of the present invention.

  Next, a vertical crusher according to an embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of the periphery of a throat in a rotary throat according to a first embodiment of the present invention, FIG. 2 is a top view of the entire throat, FIG. 3 is an enlarged top view of a first block, and FIG. FIG. 5 is an enlarged top view of the second block, FIG. 6 is a sectional view of FIG. 5B-B ′, and FIG. 7 is an enlarged top view showing an example of combining the first block and the second block. FIG. 8 is a cross-sectional view taken along the line CC ′ of FIG.

The overall schematic configuration of the vertical crusher is the same as that shown in FIG.
The throat 42 is disposed between the housing 44 and the crushing table 2 as seen from a longitudinal section as shown in FIG. 1, and has a cylindrical inner ring 70 and a cylindrical outer ring installed outside the inner ring 70. 71 and a large number of throat vanes 43 that divide the annular space formed by the inner ring 70 and the outer ring 71 in the circumferential direction.

  When the entire throat 42 is viewed from above, as shown in FIG. 2, a plurality of first blocks 501 and a plurality of second blocks 502 are circumferentially arranged in a predetermined order. Each of the blocks 501 and 502 is connected to the crushing table 2 or the like using a bolt or the like.

  The first block 501 has two or more openings 84 surrounded by the inner ring 70, the outer ring 71, and the throat vane 43. On the other hand, the second block 502 includes two or more openings 84 and a blocking portion 82 that closes the one or more openings 84.

  As shown in FIG. 1, in the case of the present embodiment, the throat 42 is fixed to the pulverizing table 2 side and constitutes a rotary throat that rotates together with the pulverizing table 2. In this embodiment, an example of a rotary throat is shown, but this throat 42 may be fixed to the inner peripheral side of the housing 44 to constitute a fixed throat.

  In the present embodiment, as shown in FIGS. 3 and 4, the first block 501 includes a part 701 of the inner ring 70 divided in the circumferential direction of the throat 42 and an outer ring 71 divided in the circumferential direction of the throat 42. Part 711 (refer to FIG. 3 for both), parts 230a and 230b of the throat vane 43 divided by the dividing surface 201c and extending to the throat upper surface 220a, and a throat vane extending from the throat lower surface 220d to the dividing surface 201b 43 part 230c, 230d (both see FIG. 4).

  On the other hand, as shown in FIGS. 5 and 6, the second block 502 includes a portion 701 of the inner ring 70 divided in the circumferential direction and a portion 711 of the outer ring 71 divided in the circumferential direction (both refer to FIG. 5). The portions 210a and 210b of the throat vane 43 divided by the dividing surface 201a and extending to the throat upper surface 220a, the portions 210c and 210d of the throat vane 43 extending from the throat lower surface 220b to the dividing surface 201d, and the dividing surface 201 The throat vane 43 is divided into b and extends to the throat upper surface 220a, and includes a closing portion 82 (see FIG. 6) provided at the upper ends of the portions 210a and 210b.

  As shown in FIGS. 4 and 6, the portions 210a to 210d and 230a to 230d of each throat vane 43 are inclined at an angle α with respect to the throat lower surface 220b for the purpose of strengthening the primary classification. This inclination angle α is set in the range of 30 to 60 degrees.

  Further, as shown in FIGS. 3 and 5, the inner peripheral length L1a of the first block 501 and the inner periphery of the second block 502 are set so that the combination of the first block 501 and the second block 502 can be arbitrarily changed. The length L1b is substantially the same dimension (L1a≈L1b), the outer peripheral length L2a of the first block 501 and the outer peripheral length L2b of the second block 502 are approximately the same dimension (L2a≈L2b), and the first block 501. The radial width Wa of the second block 502 and the radial width Wb of the second block 502 are designed to have substantially the same dimensions (Wa≈Wb), and have the same shape.

  7 and 8 are diagrams illustrating a first combination example of the first block 501 and the second block 502. In this case, three first blocks 501a to 501c and one second block 502 are illustrated in the drawing. They are combined as shown.

  As shown in FIGS. 7 and 8, for example, by combining the first block 501a and the second block 502 adjacently, a continuous throat vane 43 is formed by connecting a part 230c and a part 210a, and a part thereof. One continuous throat vane 43 is formed by connecting 230d and a portion 210b.

  Further, by combining the first block 501b and the first block 501c adjacent to each other, the portion 230c and the portion 230a are connected to form one continuous throat vane 43, and the portion 230d and the portion 230b are connected to each other. One continuous throat vane 43 is formed.

  Then, as in this example, by combining the first block 501a, the second block 502, the first block 501b, and the first block 501c, a block aggregate in which one of the throat openings 84 is closed is obtained.

  FIG. 9 is a diagram showing a second combination example of the first block 501 and the second block 502. In this case, two first blocks 501a and 501b and two second blocks 502a and 502b are shown in the figure. They are combined in such an arrangement.

  By combining in this way, one throat vane 43 which is partially connected to each other is formed, and a block aggregate in which two of the throat openings 84 are closed is obtained. As is clear from comparison between FIG. 8 and FIG. 9, the opening area of the entire throat 42 can be increased or decreased by replacing the first block 501 that does not have the blocking portion 82 and the second block 502 that has the blocking portion 82. Further, it is possible to adjust the flow rate of the conveying gas at the throat 42, to prevent the object to be crushed from falling, and to adjust the primary classification enhancement.

  The 1st block 501 and the 2nd block 502 are produced by casting as an integrated object (for example, refer to Drawing 1). Therefore, the risk of detachment of the closing plates 80a and 80b due to vibration and wear, which is a problem in the prior art, is suppressed.

  As shown in FIG. 6, the blocking portion 82 is provided at the upper end portions of the portions 210a and 210b and is not provided at the lower end portions of the portions 210c and 210d. The reason is that when the closed portion 82 is provided at the lower end of the portions 210 c and 210 d, the coal particles stay in the recess formed by the portions 210 c and 210 d and the closed portion 82.

  The dividing surfaces 201c and 201d of the first block 501 and the dividing surfaces 201a and 201b of the second block 502 are preferably perpendicular to the upper surface and the lower surface of each block. The reason is that when installing or replacing, there is no interference in the vertical direction between adjacent blocks, so that installation or replacement is facilitated.

  10 and 11 are diagrams for explaining a second block according to the second embodiment of the present invention. FIG. 10 is an enlarged top view of the second block, and FIG. 11 is a cross-sectional view taken along the line DD ′ in FIG. It is.

  As shown in FIGS. 10 and 11, in this embodiment, the blocking portion 83 is divided by the dividing surfaces 601 a and 601 b of the second block 503. When using the 2nd block 503 which has the obstruction | occlusion part 83 divided | segmented in this way, it is necessary to arrange | position two or more the said 2nd blocks 503 side by side.

  The second blocks 502 and 503 having the blocking portions 82 and 83 are preferably less than or equal to ½ of the total number of blocks constituting the throat 42. This is because when the half of the number of blocks constituting the throat 42 is the second blocks 502 and 503 having the closed portions 82 and 83, the area of the opening 84 of the throat 42 is 3/4. The flow rate of the transfer gas 61 is 4/3 times or more. This is because the pressure loss is proportional to the square of the flow velocity, so that the pressure loss is 1.78 times or more compared to the case where the second blocks 502 and 503 having the closed portions 82 and 83 are not used.

  It is desirable that the second blocks 502 and 503 having the blocking portions 82 and 83 are arranged uniformly (at equal intervals) in the entire configuration of the throat 42 (see, for example, FIG. 2). This is because when the location of the blocking portion 82 is biased, the transport gas 61 is biased.

FIG. 17 is a system diagram of a coal fired boiler plant provided with the vertical crusher according to the embodiment.
Bulk coal 60 to be crushed is put into the coal bunker 102 by the carry-in conveyor 101, and then the coal 60 is weighed by the meter 103 and put into the vertical crusher 104. Further, from the lower part of the vertical crusher 104, a high-temperature transport gas 61 that serves as both drying of the coal particles and primary air is supplied, and the coal 60 is crushed and classified in the vertical crusher 104 as described above. The pulverized coal having a predetermined particle diameter or less is supplied to the burner 106 of the coal-fired boiler device 105 and burned in the furnace.

  The combustion gas generated by this combustion is purified through the denitration device 107, the air preheater 108, the electrostatic precipitator 109, etc., and discharged from the chimney (not shown) to the atmosphere.

In the present invention, the effects according to the claims are summarized as follows.
According to the configuration of the first aspect, it is possible to provide a vertical crusher capable of adjusting the flow rate of the conveying gas, preventing the object to be crushed, and adjusting the primary classification.
According to the configuration of the second aspect, the pulverized material falling through the throat can be reduced, and the flow velocity of the carrier gas passing through the throat can be reduced.

According to the structure of Claim 3, the increase in the pressure loss of the conveyance gas which passes a throat can be suppressed.
According to the configuration of the fourth aspect, the unevenness of the blocking portion is eliminated, and accordingly, the supply of the conveying gas to the pulverizing portion is equalized.
According to the structure of Claim 5, replacement | exchange of a 1st block and a 2nd block becomes easy.

According to the structure of Claim 6, the danger of the isolation | separation of the obstruction | occlusion member by vibration or wear is suppressed, and safe operation is attained.
According to the configuration of the seventh aspect, since the concave portion is not formed on the upper surface of the throat, the problem that the pulverized material stays in the concave portion is solved.
According to the configuration of the ninth aspect, the unevenness of the blocking portion is eliminated, and accordingly, the supply of the transport gas to the pulverizing portion is equalized.
According to the structure of Claim 10, it can respond easily to changes, such as a charcoal type and the operating condition of a boiler.

  In the above embodiment, the case of a vertical pulverizer for pulverizing coal has been described. However, the vertical pulverizer according to the present invention can also be applied to an apparatus for pulverizing other objects to be pulverized such as cement.

2: Grinding table,
3: Crusher,
40: Gas duct for conveyance,
41: Windbox,
42: Throat,
43: Throat vane
44: housing,
60: coal,
61: conveying gas,
70: Inner ring,
71: outer ring,
82: occlusion,
83: a divided blockage,
84: Throat opening,
104: vertical crusher
105: Coal-fired boiler equipment,
201a to 201d: divided surfaces,
210a-210d, 230a-230d: a part of the throat vane,
220a: top surface of the throat,
220b: the lower surface of the throat,
501: the first block,
502: Second block,
503: a second block obtained by dividing the blocking portion,
601a, 601b: a divided surface of the second block obtained by dividing the blocking portion,
610a to 610d: a part of the throat vane of the second block obtained by dividing the blocking portion,
701: a part of the inner ring,
711: a portion of the outer ring,
B: Crushing part,
C: Classification part.

Claims (9)

A housing;
A crushing table rotatably installed inside the housing;
A plurality of crushers arranged on the crushing table;
An annular space that is disposed between the housing and the crushing table and is formed by a cylindrical inner ring, a cylindrical outer ring that is installed outside the inner ring, and the inner ring and the outer ring. A throat consisting of a number of throat vanes that divide the
With a windbox at the bottom of the throat,
The object to be pulverized is pulverized by biting the pulverization table and the pulverizer to generate pulverized particles, and the carrier gas supplied to the wind box is jetted to the outer periphery of the pulverization table through the throat vane. In the vertical crushing apparatus for conveying the pulverized particles upward,
The throat comprises a block divided into a plurality along the circumferential direction,
The block includes a first block having two or more throat openings surrounded by the inner ring, the outer ring, and the throat vane, one or more throat openings, and one or more throat openings. A vertical crusher characterized in that it is configured by combining two types of blocks, the second block, having a blocking portion for closing the block. In the vertical crushing apparatus according to claim 1,
A vertical crusher comprising a combination of the first block and the second block, wherein a throat is fixed to the crushing table side, and the throat rotates together with the crushing table. In the vertical crushing apparatus according to claim 1 or 2,
The vertical crusher characterized in that the ratio of the second block having the closed portion to the total number of blocks constituting the throat is regulated to ½ or less. The vertical crusher according to any one of claims 1 to 3,
A vertical crusher characterized in that the second blocks having the closed portion are arranged so as not to be adjacent to each other. In the vertical crushing apparatus according to any one of claims 1 to 4,
The vertical crusher characterized in that the first block and the second block have the same shape and size, and the first block and the second block are interchangeable. In the vertical crushing apparatus according to any one of claims 1 to 5,
The inner ring portion of the first block, the outer ring portion, and the throat vane portion are integrally formed, and the inner ring portion, the outer ring portion, and the throat vane portion of the second block, A vertical crusher characterized in that the closing portion is formed of a single piece. The vertical crushing apparatus according to any one of claims 1 to 6,
The vertical crushing apparatus, wherein the closing portion of the second block is formed so as to close the upper throat opening. The vertical crusher according to any one of claims 1 to 7,
A vertical crusher characterized in that the second blocks are evenly arranged in the throat. A vertical crusher;
In a pulverized coal fired boiler plant equipped with a pulverized coal fired boiler device that burns pulverized coal produced by pulverization with the vertical pulverizer,
A pulverized coal-fired boiler plant, wherein the vertical pulverizer is the vertical pulverizer according to any one of claims 1 to 8.

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