JP2011240233A - Vertical type crushing device, and coal burning boiler device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical type crushing device capable of reducing pressure loss in the device, and reducing wear of a peripheral housing.SOLUTION: This vertical type crushing device is configured to crush a crushing object with a rotary table 2 and a crushing roller 3 and spray a crushed particle group thereof upward by a carrying gas 61 spewed from a throat part 42 and having turning force to be carried to a classifying part. The vertical type crushing device is equipped with a clustered zone particle dispersion means 68 for spraying a part of the carrying gas 61 to falling particles 76 falling due to the force of gravity before particles large in granularity out of the particle group sprayed by the carrying gas 61 reach the classifying part, and a clustered zone formed by merging of a new particle group sprayed from the float part 42 and having high particle concentration to disperse the particles in the clustered zone.

Description

  The present invention relates to a vertical pulverizer capable of pulverizing a solid raw material with a pulverizing roller and a rotary table and adjusting it to a predetermined particle size distribution with a classifier, and is particularly suitable as a pulverized coal manufacturing apparatus for a coal fired boiler apparatus. The present invention relates to a vertical crusher.

  In a coal fired boiler apparatus for thermal power generation that burns pulverized coal as fuel, a vertical pulverizer is generally used as a pulverized coal production apparatus.

  FIG. 15 is a schematic configuration diagram of a conventional vertical crushing apparatus, and FIG. 16 is a schematic configuration diagram of a pulverization unit viewed from the line XX in FIG.

  As shown in FIG. 15, the vertical crusher includes a driving unit A that rotates the rotary table 2, and a pulverizing unit B that crushes the coal 60 that is a raw material of pulverized coal by the rotation table 2 and the crushing roller 3. The classifying unit C that is installed at the upper part of the pulverizing unit B and classifies the pulverized coal into an arbitrary particle size, and the pulverized coal sent from the classifying unit C to the coal feeding boilers 31 connected to the coal fired boiler. The distribution unit D mainly distributes.

Next, the operation of this vertical grinder will be described with reference to FIG.
Coal 60 supplied from coal supply pipe 1 falls to the center of turntable 2 as shown by the arrow. The rotary table 2 is rotationally driven in a predetermined direction by a drive motor 51 via a speed reducer 50. The coal 60 that has fallen on the rotary table 2 is moved to the outer periphery by drawing a spiral trajectory on the rotary table 2 due to the centrifugal force accompanying the rotation, and is caught between the rotary table 2 and the tire-like grinding roller 3. And crushed.

  The pulverized coal is blown upward by primary air 61 (conveyance air) introduced from a throat 42 provided around the turntable 2. Among the particles 62 that have been blown up, particles having large particles fall by gravity while being transported to the classification unit C, and are returned to the pulverization unit B (primary classification). Reference numeral 76 denotes a falling particle having a large particle separated by the primary classification.

  The ascending particles 69 reaching the classification part C are classified into fine particles 67 having a predetermined particle size or less and coarse particles 63 exceeding the predetermined particle size (secondary classification), and the coarse particles 63 fall into the pulverization part B and are pulverized again. Is done. On the other hand, the fine particles 67 that have passed through the classification section C are distributed to the plurality of coal feeding pipes 31 in the distributor 30 and are sent as product fines 64 to a coal fired boiler (not shown).

  The primary air 61 is introduced from the side surface of the primary air wind box 41 through the primary air duct 40, rectified in the primary air wind box 41, and then ejected upward from the throat 42.

FIG. 17 is an enlarged cross-sectional view of the vicinity of a throat portion in a conventional vertical crusher.
As shown in the figure, the throat 42 is an air flow path formed by being surrounded by the inner ring 44. In this example, the throat 42 is a rotary swirl flow throat connected to the turntable 2 side, but may be a fixed swirl flow throat connected to the outer peripheral housing 46 side.

  15 to 17, reference numeral 5 denotes a pressure frame, 6 denotes a roller bracket, 7 denotes a roller pivot, 8 denotes a pressure rod, 9 denotes a pressure device, 10 denotes a fixed classifying mechanism, and 11 denotes a recovery cone. , 12 is a fixed fin, 20 is a rotary classification mechanism, 21 is a rotary fin, 22 is a rotary shaft, 23 is a classifier motor, 45 is an outer ring, 46 is an outer housing, 47 is an inclined member, and 65 is a classifier C. It is a particle group that flows in.

  Examples of prior art documents related to this type of vertical crusher include the following patent documents.

JP 2006231111 A JP 58-193743 A JP 58-207953 A JP 59-102451

  In recent years, in power plants, price competition has intensified in Japan and overseas due to the liberalization of electric power and the globalization of equipment supply. Particularly in the vertical crusher, it is desired to reduce the driving power in order to reduce the power generation cost.

  About half of the driving power of the vertical crushing apparatus is occupied by the power of the blower fan of the conveying air (primary air 61) for drying and conveying the pulverized coal powder. Therefore, reducing the pressure loss in the vertical crusher is an important issue, and reducing this is an effective means for achieving power reduction. There are various and various causes for the generation of pressure loss in the vertical crushing apparatus. One of the causes is an increase in pressure loss due to the generation of a dense zone of particles on the outer periphery of the crushing roller.

  18 is a plan view of the flow of primary air ejected from the throat 42, FIG. 19 is a diagram of the flow of primary air ejected from the throat 42 as viewed from the vertical direction, and FIG. 20 is a view of the grinding roller 3 and the outer housing. FIG. 6 is a diagram for explaining a particle dense zone 77 generated between 46;

  As shown in FIG. 18, a turning force is given by the throat 42, and the primary air flow 70 is ejected toward the inner wall of the outer peripheral housing 46. Then, the primary air flow 70 colliding with the inner wall of the outer peripheral housing 46 becomes a rising primary air flow 75 that rises along the circumferential direction of the inner wall of the outer peripheral housing 46, as shown in FIG. As shown in FIG. 4, the particle group 62 pulverized by the pulverizing roller 3 is blown up to the classification part C at the upper part of the pulverizing apparatus.

  Of the particles 62 that have been blown up, particles having a large particle size change direction and fall by gravity (falling particles 76). Then, the falling particles 76 between the crushing roller 3 and the outer peripheral housing 46 and the particle group 62 blown up from below join together to generate a particle dense zone 77 (see FIG. 20) where the particle concentration is locally increased. This increases the pressure loss in this region and eventually increases the pressure loss in the grinding device.

  As shown in FIG. 16, the particle dense band 77 is generated particularly in the region behind (backward) the crushing roller 3 where the coal powder that has been crushed by the rotary table 2 and the crushing roller 3 is discharged. It has been confirmed by various experiments that it is easy.

  In the conventional vertical pulverizer, the particle group 62 pulverized by the pulverizing roller 3 is carried by the primary air flow 70 having a turning force and collides with the outer peripheral housing 46 as shown in FIGS. There is also a problem that the wall surface of the outer peripheral housing 46 is worn 79.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to reduce the pressure loss inside the apparatus and reduce the wear of the outer peripheral housing, and the coal slag using the same. It is to provide a boiler device.

In order to achieve the above object, the first means of the present invention is a pulverizing section having a rotating table and a plurality of pulverizing rollers placed on the upper surface of the rotating table and rotating as the rotating table rotates. ,
A wind box to which a transfer gas is supplied;
A throat unit that is installed on the outer periphery of the pulverizing unit and applies a turning force to the conveying gas supplied to the wind box and ejects it from the outer peripheral unit of the rotary table;
A classification unit that is installed above the pulverization unit and classifies the particle group pulverized in the pulverization unit;
A housing for accommodating the pulverizing section, the wind box and the classification section;
The object to be crushed dropped on the rotating table is pulverized by the engagement of the rotating table and the pulverizing roller, and the pulverized particles are blown upward by the conveying gas having a turning force ejected from the throat part. Thus, it is intended for a vertical crushing apparatus that conveys to the classification unit.

  And among the particle groups blown upward by the carrier gas, the falling particles that fall by gravity before the particles having a large particle size reach the classification part, and the new particle group blown up from the throat part are A dense band particle dispersion means for dispersing a particle in the dense zone by injecting a part of the carrier gas to the dense zone having a high particle concentration formed by merging is provided. It is what.

  The second means of the present invention is characterized in that, in the first means, the dense particle dispersion means is provided in the wake portion in the rotating table rotation direction of the crushing roller.

  According to a third means of the present invention, in the first or second means, the dense particle dispersion means is disposed between the housing and the throat portion so as to define the wind box, and the throat portion extends from the housing. It is comprised by the gas ejection hole provided in the inclined member descend | falling toward the part side.

  According to a fourth means of the present invention, in the third means, the gas ejection hole is not formed in a portion of the inclined member facing a roller bracket that rotatably supports the crushing roller. Is.

  According to a fifth means of the present invention, in the third means, the ratio (n × A2 / A1) of the total opening area (n × A2) of the gas ejection holes to the total opening area (A1) of the throat portion is set to 0. It is characterized by being restricted to a range of 1 to 1.3.

  The sixth means of the present invention is the ratio of the length (L2) from the lower end of the inclined member to the upper end of the gas ejection hole with respect to the length (L1) from the lower end to the upper end of the inclined member in the third means. (L2 / L1) is regulated within a range of 0.1 to 0.9.

  The seventh means of the present invention is characterized in that, in the third means, a nozzle is installed in the gas ejection hole of the inclined member.

  According to an eighth means of the present invention, in the seventh means, the nozzle protrudes above the surface of the inclined member.

A ninth means of the present invention is a coal fired boiler apparatus provided with a vertical coal pulverizer for pulverizing coal and a coal fired boiler for burning pulverized coal obtained by pulverization with the vertical pulverizer with a pulverized coal burner. In
The vertical crushing device is a vertical crushing device of any one of the first to eighth means.

  The present invention is configured as described above, and can effectively reduce the pressure loss at the throat while also reducing the wear of the outer peripheral housing, and can improve the reliability during operation. A pulverizing apparatus and a coal fired boiler apparatus using the same can be provided.

1 is a schematic configuration diagram of a vertical crusher according to a first embodiment of the present invention. It is a schematic block diagram of the grinding | pulverization part seen from the YY line of FIG. It is an expanded sectional view near the throat part of the vertical crusher. FIG. 3 is an enlarged cross-sectional view taken along the line Z-Z. In the 1st Embodiment, it is a figure for demonstrating the state which diffuses the high concentration particle group in a dense zone with the flow of the air ejected from the gas ejection hole. It is a figure which compares and shows the pressure loss amount (DELTA) P of the conventional vertical grinding apparatus and the vertical grinding apparatus which concerns on this embodiment. It is a figure which shows the flow of the air in a throat part from a perpendicular direction. It is a figure which shows the flow of the air in a throat part from a horizontal direction. It is a figure which compares and shows the amount of wear in the outer periphery housing of the conventional vertical crushing apparatus and the vertical crushing apparatus which concerns on this embodiment. It is a schematic block diagram of the grinding | pulverization part seen from the horizontal direction of the vertical crushing apparatus which concerns on the 2nd Embodiment of this invention. It is an expanded sectional view of the throat part of the vertical crushing apparatus which concerns on the 3rd Embodiment of this invention. It is an expanded sectional view of the throat part of the vertical crushing apparatus which concerns on the 4th Embodiment of this invention. It is an expanded sectional view of the throat part of the vertical crushing apparatus which concerns on the 5th Embodiment of this invention. It is a schematic block diagram of the coal fired boiler apparatus provided with the vertical grinding apparatus which concerns on embodiment of this invention. It is a schematic block diagram of the conventional vertical mill. FIG. 15 is a schematic configuration diagram of a pulverization unit viewed from the line XX. It is an expanded sectional view near the throat part in the vertical crusher. It is the figure which looked at the flow of the primary air ejected from a throat from the plane. It is the figure which looked at the flow of the primary air ejected from a throat from the perpendicular direction. It is a figure for demonstrating the dense zone of the particle | grains produced between a grinding | pulverization roller and an outer peripheral housing.

Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 is a schematic configuration diagram of a vertical crushing apparatus according to the first embodiment, FIG. 2 is a schematic configuration diagram of a pulverization unit viewed from the line YY in FIG. 1, and FIG. FIG. 4 is an enlarged sectional view taken along the line Z-Z in FIG.

  The overall schematic configuration and operation of the vertical crushing apparatus according to the present embodiment are substantially the same as those of the conventional apparatus described above, and thus a duplicate description is omitted. As shown in FIG. 3, the throat 42 in this embodiment is installed in an annular gap between the rotary table 2 and the outer peripheral housing 46, an inner ring 44, and an outer ring 45 disposed on the radially outer side of the inner ring 44, An air flow path surrounded by a plurality of throat vanes 43 disposed in the circumferential direction between the inner ring 44 and the outer ring 45 is formed. The inner ring 44, the outer ring 45, and the throat vane 43 are supported on the outer peripheral portion of the rotary table 2 and rotate with the rotation of the rotary table 2, so that they are called rotary swirl flow throats.

  The throat 42 is not limited to this embodiment, and it is sufficient that a plurality of throat vanes 43 are provided in the circumferential direction at least in the annular gap between the rotary table 2 and the outer peripheral housing 46.

  In the vertical crusher, since the crushing roller 3 is supported at the same position by the roller bracket 6, a plurality of throat vanes 43 are installed in the gap between the rotary table 2 and the outer housing 46 for the purpose of strengthening the primary classification. A turning force is applied to the primary air 61 ejected from the throat 42.

  Therefore, the primary air 61 ejected from the throat 42 is ejected in the direction of the outer peripheral housing 46 after passing through the throat, as will be described later, and then rises while turning the inner wall of the outer peripheral housing 46 along the circumferential direction. .

Next, the function of the throat 42 will be described. The throat 42 has a function of ejecting the primary air 61 from the outer peripheral portion of the turntable 2.
FIG. 4 is a diagram illustrating the flow of primary air passing through the throat 42. The primary air 61 flowing in from the primary air wind box 41 (see FIG. 3) passes through the throat 42 along the inclination direction of the throat vane 43 and is ejected to the pulverizing section B. By tilting the throat vane 43, a swirling force is given to the primary air flow 70 ejected to the pulverizing section B, and the powder crushed by the crushing roller 3 with the primary air flow 70 to which the swirling force is applied is substantially reduced. It is possible to blow up uniformly.

  In addition, the inclination angle θ2 of the throat vane 43 shown in the figure is set to 45 ° or more (θ2 ≧ 45 °), that is, the throat vane 43 is placed so that the throat vane 43 is turned down, so that the primary air flow 70 is parallel to the rotary table 2. The velocity component can be made larger than the velocity component perpendicular to the rotary table 2, and the turning force can be effectively applied to the primary air flow 70.

  As shown in FIG. 19, the particle group 62 (see FIG. 1) pulverized by the pulverizing roller 3 is removed from the upper part of the pulverizer by the primary air flow 75 that rises while turning the inner wall of the outer peripheral housing 46 along the circumferential direction. It blows up to the classification part C.

  At this time, in the conventional vertical crusher, as shown in FIG. 20, among the particles group 62 blown up, particles having a large particle size fall by gravity, and the falling particles 76 and the particle group 62 blown up from below merge. As a result, a dense zone 77 in which the particle concentration locally increases between the grinding roller 3 and the outer peripheral housing 46 is a factor of pressure loss in the grinding device.

  In order to solve this problem, in the present embodiment, as shown in FIG. 3, the structure is located between the outer peripheral housing 46 and the throat 42, is connected to the inner wall of the outer peripheral housing 46, and descends from the outer peripheral housing 46 toward the throat 42 side. A plurality of gas ejection holes 68 are installed in the inclined member 47 along the circumferential direction so as to eject primary air toward the central direction of the pulverizer (see FIG. 2). In addition, this inclination member 47 is one member which divides and forms the wind box 41, as shown in FIG.1 and FIG.3.

  The inclination angle θ1 (see FIG. 3) of the inclined member 47 is about 20 ° ≦ θ1 ≦ 70 °, which is the same as that of the conventional pulverizer. The provision of the gas ejection holes 68 allows the primary air 61 to flow into the pulverizing part not only through the throat 42 but also through the gas ejection holes 68.

  As a result, as shown in FIG. 5, an air flow 71 is generated from the gas ejection hole 68 toward the center obliquely upward of the pulverizer, and the air flow 71 collides with the particle dense zone 77 (see FIG. 20). The high-concentration particle group existing in the band 77 can be diffused to reduce the pressure loss in this region.

  In the figure, 78 is a particle diffused by the air flow 71. In the figure, in order to identify the diffused particle 78, it is drawn as one lump for convenience. However, the particle is actually diffused and shown in the figure. It is not like a lump. The gas ejection hole 68 may have an appropriate shape such as a round hole or a slit as long as it has an effect of diffusing the particles in the dense band 77 regardless of its shape.

  FIG. 6 is a diagram comparing the pressure loss amount ΔP between the conventional vertical crusher and the vertical crusher according to the present embodiment. This figure shows the pressure loss amount ΔP of the vertical grinder according to the present embodiment when the pressure loss amount ΔP of the conventional vertical grinder is 1.

  In this test, the throat 42 in the conventional vertical pulverizer and the vertical pulverizer according to this embodiment has the same structure, and the supplied primary air flow rate is also equal. In the vertical crushing apparatus according to the present embodiment, the ratio of the total opening area of the plurality of gas ejection holes 68 to the total opening area of the throat 42 is set to 0.5. As is apparent from this figure, the pressure loss ΔP could be reduced by about 60% compared to the conventional vertical crusher.

  Assuming that the total opening area of the entire throat 42 is A1, the opening area of one gas ejection hole 68 is A2, and the total opening area of all (n) gas ejection holes 68 is n × A2, n × A2 with respect to A1 When the ratio (n × A2 / A1) is less than 0.1, the diameter of the gas ejection hole 68 is substantially reduced, and when the air flow 71 passes through the gas ejection hole 68, the flow path rapidly contracts and expands rapidly. As a result, the air flow 71 cannot effectively diffuse the high-concentration particle group in the dense zone 77 due to the influence of the separation vortex generated. Accordingly, it is desirable that (n × A2 / A1) = 0.1 or more.

  When (n × A2 / A1) = 1.3 is exceeded, the amount of the air flow 71 passing through the gas ejection hole 68 is increased, and on the contrary, the amount of the air flow 70 passing through the throat 42 is decreased. Since the flow rate of air discharged from the throat 42 decreases and the amount of coal powder falling from the gas ejection holes 68 increases, it is desirable that (n × A2 / A1) = 1.3 or less. Furthermore, by making (n × A2 / A1) = 0.6 or less, the coal powder almost does not fall from the gas ejection holes 68.

  For this reason, (n × A2 / A1) may be regulated within the range of 0.1 to 1.3, preferably within the range of 0.1 to 0.6.

Next, the wear of the outer peripheral housing 46 will be described.
In the conventional vertical crusher, as shown in FIGS. 17 and 18, the primary air flow 70 given a turning force by the throat 42 is ejected toward the outer housing 46, and the flow velocity in the vicinity of the outer housing 46 is high. Become. Further, the particle group 62 carried by the primary air flow 70 collides with the outer peripheral housing 46, so that the peripheral wall of the outer peripheral housing 46 is worn 79.

  On the other hand, in this embodiment, as shown in FIGS. 7 and 8, the air flow 70 ejected from the throat 42 is caused by the air flow 71 ejected from the gas ejection hole 68 toward the center of the pulverizer. Shifting toward the center of the crushing part (see FIG. 8), the air flow changes to the air flow 72 (see FIG. 7). This air flow shift reduces the air flow velocity in the vicinity of the outer housing 46, thereby reducing wear on the outer housing 46.

  FIG. 9 is a diagram showing a comparison of the amount of wear in the outer peripheral housing 46 of the conventional vertical crusher and the vertical crusher according to the present embodiment. In this figure, the wear amount of the vertical crusher according to the present embodiment when the wear amount of the conventional vertical crusher is set to 1 is shown.

  In this test, the throat 42 in the conventional vertical pulverizer and the vertical pulverizer according to this embodiment has the same structure, and the supplied primary air flow rate is also equal. In the vertical crushing apparatus according to this embodiment, the ratio of the total opening area of the gas ejection holes 68 to the total opening area of the throat 42 is set to 0.5. As can be seen from this figure, the amount of wear on the outer peripheral housing 46 can be reduced as compared with the conventional vertical crusher.

  As shown in FIG. 3, the inclination angle θ1 of the inclined member 47 is 45 °, the length of the inclined member 47 from the lower end to the upper end of the inclined member 47 is L1, and from the lower end of the inclined member 47 to the upper end of the gas ejection hole 68 The length is L2, (n × A2 / A1) = 0.5, the diameter of the gas ejection hole 68 is the same, and the installation position of the gas ejection hole 68 is changed in various ways to reduce the amount of wear in the outer housing 46. Tested.

  As a result of the wear test, when the position (L2 / L1) of the gas ejection hole 68 installed on the inclined member 47 is less than 0.9, that is, when the gas ejection hole 68 is formed near the lower end of the inclined member 47, Since the direction of the air flow 71 from the gas ejection hole 68 becomes relatively vertical, the force for changing the air flow 70 to the flow toward the center of the pulverizing portion is weak, so that the effect of reducing wear on the outer peripheral housing 46 is achieved. Can not fully demonstrate.

  In order to enhance the wear reduction effect, the position L2 of the gas ejection hole 68 installed on the inclined member 47 is installed at a position where (L2 / L1) ≦ 0.9 with respect to the length L1 of the inclined member 47. In order to maintain the strength of the construction part of the gas ejection hole 68, it is desirable to satisfy L2 / L1 ≧ 0.1. Therefore, (L2 / L1) may be regulated within a range of 0.1 to 0.9 [0.1 ≦ (L2 / L1) ≦ 0.9].

(Second Embodiment)
FIG. 10 is a schematic configuration diagram seen from the plane of the pulverization unit of the vertical pulverizer according to the second embodiment of the present invention.

  As shown in FIG. 1, the crushing roller 3 is rotatably supported by a roller bracket 6, and the roller bracket 6 is located outside the crushing roller 3 and above the inclined member 47. Therefore, the roller bracket 6 can be a resistor against the air flow 71 ejected from the gas ejection hole 68.

  Therefore, in this embodiment, the pressure loss is further reduced by avoiding the resistance of the roller bracket 6 against the air flow 71 without forming the gas ejection hole 68 at the position of the inclined member 47 facing the roller bracket 6. Can be reduced.

  Even if the gas ejection hole 68 is not formed at a position facing the roller bracket 6 of the inclined member 47, the position where the particle dense band 77 is easily formed as shown in FIG. This is a region of the region and is shifted in position, so that the diffusion effect of the particles in the dense zone 77 hardly changes.

(Third embodiment)
FIG. 11 is an enlarged cross-sectional view of the vicinity of the throat portion according to the third embodiment of the present invention. In the present embodiment, a downstream nozzle 73 having a certain length in the axial direction is installed in the upper opening of the gas ejection hole 68 formed in the inclined member 47.

  Due to the rectification effect resulting from the installation of the downstream nozzle 73, the air flow 71 directed toward the center of the crushing device ejected from the gas ejection hole 68 is strengthened. The strengthening of the air flow 71 enhances the dispersion effect of the particle dense band 77 and effectively changes the primary air after passing through the throat 42 into the flow 72 toward the center of the pulverizer.

  Further, in the case where only the gas ejection holes 68 are formed in the inclined member 47, there is a possibility that coal powder slides and falls from the inclined member 47 to the gas ejection holes 68, but the downstream nozzle 73 is provided at the upper opening of the gas ejection hole 68. By installing, the coal powder which slides down from the inclined member 47 to the gas ejection hole 68 is eliminated.

(Fourth embodiment)
FIG. 12 is an enlarged cross-sectional view of the vicinity of the throat portion according to the fourth embodiment of the present invention. In the present embodiment, the upstream nozzle 74 is installed in the lower opening of the gas ejection hole 68 formed in the inclined member 47.

  By the rectifying effect due to the installation of the upstream nozzle 74, the air flow 71 directed toward the center of the pulverizer ejected from the gas ejection hole 68 is strengthened, and the primary air after passing through the throat 42 is effectively directed toward the center of the pulverizer. It becomes possible to change to the flow 72 to The upstream nozzle 74 may protrude up to the top of the inclined member 47, and the rectifying effect is further enhanced by lengthening the nozzle flow path.

(Fifth embodiment)
FIG. 13 is an enlarged cross-sectional view of the vicinity of the throat portion according to the fifth embodiment of the present invention. This embodiment is an embodiment of a so-called fixed swirl flow throat in which a throat 42 constituted by a throat vane 43, an inner ring 44 and an outer ring 45 is connected to an inner peripheral portion of an inclined member 47.

  In order to prevent the coal powder from falling from the gap formed between the throat 42 (inner ring 44) and the turntable 2, a ring sheet 48 is installed on the outer periphery of the turntable 2.

  Also in this fixed swirl flow throat, the gas ejection hole 68 is not formed at the position facing the roller bracket 6 of the inclined member 47 as shown in FIG. 10, and the gas ejection hole 68 as shown in FIG. A configuration in which the downstream nozzle 73 is installed or a configuration in which the upstream nozzle 74 is installed in the gas ejection hole 68 as shown in FIG. 12 can be applied as appropriate, and similar effects can be achieved.

FIG. 14 is a schematic configuration diagram of a coal fired boiler apparatus provided with a vertical pulverizer according to an embodiment of the present invention.
As shown in the figure, the combustion air A fed by the air blower 81 is separated into primary air A1 and secondary air A2, and the primary air A1 is directly cooled by the primary air air blower 82 as cold air. It is branched into what is sent to the crusher 83 and what is heated by the exhaust gas air preheater 84 and sent to the vertical crusher 83. The cold air and the warm air are mixed and adjusted so that the mixed air has an appropriate temperature, and supplied as primary air 61 to the vertical crusher 83.

  After the coal 60 is put into the coal bunker 85, it is supplied to the vertical crusher 83 by the coal feeder 86 and is pulverized. The pulverized coal generated by being pulverized while being dried by the primary air 61 is conveyed by the primary air 61, sent to the coal fired boiler 88 through the pulverized coal burner 87, and burned. The secondary air A <b> 2 is heated by the steam air preheater 89 and the exhaust gas air preheater 84, sent to the wind box 90, and used for the combustion of pulverized coal in the coal fired boiler 88.

  The exhaust gas generated by the combustion of the pulverized coal is dust removed by the electrostatic precipitator 91, nitrogen oxides are reduced by the denitration device 92, sucked by the induction blower 93 through the exhaust gas air preheater 84, and sulfur content by the desulfurization device 94. Is removed and the system is released from the chimney 95 into the atmosphere.

  DESCRIPTION OF SYMBOLS 1 ... Coal feeding pipe, 2 ... Rotary table, 3 ... Grinding roller, 6 ... Roller bracket, 31 ... Coal feeding pipe, 40 ... Primary air duct, 41 ... Primary Air wind box, 42 ... throat, 43 ... throat vane, 44 ... inner ring, 45 ... outer ring, 46 ... outer housing, 47 ... inclined member, 60 ... coal 61 ... primary air, 62 ... blown up particle group, 63 ... coarse particle, 64 ... product fine powder, 65 ... particle group flowing into classification part, 67 ... fine particle, 68: Gas ejection holes, 69: Ascending particles, 70: Air flow ejected from the throat, 71: Air flow ejected from the gas ejection holes, 72: To the center of the pulverizer Shifted air flow, 73 ... downstream nozzle, 74 ... upstream nose 75 ... Ascending primary air flow, 76 ... Falling particles, 77 ... Particle dense zone, 78 ... Diffused particles, 83 ... Vertical crusher, 87 ... Pulverized coal Burner, 88 ... Coal fired boiler, A ... Drive unit, B ... Crushing unit, C ... Classification unit, D ... Distribution unit.

Claims (9)

A pulverizing section having a rotary table and a plurality of pulverizing rollers placed on the upper surface of the rotary table and rotating with the rotation of the rotary table;
A wind box to which a transfer gas is supplied;
A throat unit that is installed on the outer periphery of the pulverizing unit and applies a turning force to the conveying gas supplied to the wind box and ejects it from the outer peripheral unit of the rotary table;
A classification unit that is installed above the pulverization unit and classifies the particle group pulverized in the pulverization unit;
A housing for accommodating the pulverizing section, the wind box and the classification section;
The object to be crushed dropped on the rotating table is pulverized by the engagement of the rotating table and the pulverizing roller, and the pulverized particles are blown upward by the conveying gas having a turning force ejected from the throat part. In the vertical crusher that transports to the classification unit,
Of the particle groups blown upward with the carrier gas, the falling particles that fall by gravity before the particles having a large particle size reach the classification part and the new particle group blown up from the throat part merge. A dense band particle dispersion means for spraying a part of the carrier gas to disperse particles in the dense band is provided for the dense band having a high particle concentration. Vertical crusher. The vertical crushing apparatus according to claim 1,
The dense band particle dispersion means comprises:
A vertical crushing device provided at each downstream portion of the crushing roller in the rotating table rotation direction. In the vertical crushing apparatus according to claim 1 or 2,
The dense band particle dispersion means comprises:
In order to partition and form the wind box, it is arranged between the housing and the throat portion, and is composed of a gas ejection hole provided in an inclined member descending from the housing toward the throat portion side. Mold crusher. In the vertical crushing apparatus according to claim 3,
The vertical pulverizing apparatus is characterized in that the gas ejection hole is not formed in a portion of the inclined member facing a roller bracket that rotatably supports the pulverizing roller. In the vertical crushing apparatus according to claim 3,
The ratio (n × A2 / A1) of the total opening area (n × A2) of the gas ejection holes to the total opening area (A1) of the throat portion is restricted to a range of 0.1 to 1.3. Vertical crusher. In the vertical crushing apparatus according to claim 3,
The ratio (L2 / L1) of the length (L2) from the lower end of the inclined member to the upper end of the gas ejection hole to the length (L1) from the lower end to the upper end of the inclined member is in the range of 0.1 to 0.9. A vertical crusher characterized in that In the vertical crushing apparatus according to claim 3,
A vertical crusher characterized in that a nozzle is installed in a gas ejection hole of the inclined member. The vertical crusher according to claim 7,
The vertical crusher characterized in that the nozzle protrudes above the surface of the inclined member. In a coal fired boiler apparatus equipped with a coal fired boiler for grinding coal, and a coal fired boiler that burns pulverized coal obtained by pulverization in the vertical grinder with a pulverized coal burner,
A coal fired boiler apparatus, wherein the vertical grinder is the vertical grinder of any one of claims 1 to 8.

Images