JP2011161306A - Biomass mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biomass mill capable of improving its crushing efficiency and of increasing its crushing capacity by increasing the opportunity of crushing wooden biomass by applying an impact onto the wooden biomass left uncrushed by a pressure roller to disintegrate the same. <P>SOLUTION: The biomass mill includes a housing 8 constituting a classifying chamber 5, a classifier 32 accommodated in the upper part of the housing 8, a crushing table 2 accommodated in the lower part of the housing 8 to be rotated by a table driving device 11, a pressure roller unit 14 comprising a pressure roller 3 to be pressed onto the crushing table 2, a primary air chamber 4 for primary air to be introduced thereinto formed below the crushing table 2, a blowout port 6 for blowing out the primary air present in the primary air chamber 4 via the periphery of the crushing table 2, a chute 21 for feeding wooden biomass into the center of the crushing table 2, and a classifying member 34 that has a distributing function and is disposed on a position facing the blowout port 6 tiltingly in a manner of distancing itself from the chute 21 from the lower end to the upper end thereof. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a biomass mill for pulverizing woody biomass as boiler fuel.

  Currently, coal is mainly used as solid fuel for boilers, but as a measure to reduce CO2, the use of woody biomass with low environmental impact as fuel is being studied.

  In order to use woody biomass as fuel for a pulverized coal-fired boiler, it is necessary to grind woody biomass such as wood chips and wood pellets so that the burner can be burned.

  When coal is mixed with a woody biomass mill and used as fuel, it can be mixed and ground with existing coal mills if the amount of woody biomass is small, but if the amount of woody biomass used increases, It is necessary to pulverize based biomass alone.

  In addition, a pulverization apparatus based on a coal roller mill for pulverizing coal as an apparatus for pulverizing woody biomass can be achieved at a low cost without significant improvements and major equipment changes.

  First, referring to FIG. 4, an outline of a vertical mill 1 for pulverizing coal will be described.

  A crushing table 2 for crushing coal is erected via a table driving device (not shown), and the crushing table 2 is rotated at a constant speed by the table driving device.

  Above the crushing table 2, a plurality of pressure roller units (not shown) having pressure rollers 3 are provided radially from the rotation center of the crushing table 2, for example, three at intervals of 120 °. The roller 3 is pressed onto the crushing table 2 by a roller pressing device (not shown).

  A primary air chamber 4 is formed below the crushing table 2, and a classification chamber 5 is formed above the crushing table 2. A primary air outlet 6 is provided around the pulverizing table 2 over the entire circumference, and the outlet 6 communicates the primary air chamber 4 and the classification chamber 5. In the figure, reference numeral 8 denotes a housing.

  The primary air chamber 4 is provided with a primary air supply port (not shown). The primary air supply port is connected to a primary air supply means (not shown) and communicates with the primary air chamber 4. ing.

  During the coal pulverization process, lump coal is dropped from the coal supply device (not shown) onto the center of the pulverization table 2, and the pulverization table 2 is rotated by the table driving device, and the primary air supply port (not shown) The primary air supplied from the air passes through the primary air chamber 4 and is discharged from the outlet 6 to the classification chamber 5.

  The pressure roller 3 is rotatable and is driven to rotate by the crushing table 2. The coal dropped on the crushing table 2 moves in the outer circumferential direction by the rotation of the crushing table 2, It is pulverized by being bitten by the pressure roller 3.

  The pulverized coal particles are further moved in the outer circumferential direction by the rotation of the pulverization table 2, and are blown upward by the primary air that is ejected at a high speed from the blowout port 6, and pass through the classification chamber 5 to be predetermined. It is classified to a particle size equal to or smaller than the diameter, and is fed to a boiler through a feed pipe (not shown).

  However, when the woody biomass is pulverized alone, the woody biomass is a lightweight fiber, so that it is entangled with each other and the amount of movement on the pulverization table 2 is not as smooth as that of coal. For this reason, the pulverized woody biomass is laid on the pulverization table 2, and the pulverized powder is difficult to move to the outer periphery of the pulverization table 2, and the powder is blown up to the primary air. Less frequent.

  Further, since the woody biomass has a small specific gravity, it passes between the pressure rollers 3 and 3 without being pulverized by the pressure roller 3, moves to the outer peripheral portion of the pulverization table 2, and is blown up to the primary air. There is a case. The unpulverized woody biomass blown up to the primary air is bounced by a classifier (not shown) and partly falls outside the outlet 6 along the inner wall of the vertical mill 1. The pressure roller 3 is not crushed and the pulverization does not proceed effectively.

  When the powder is not smoothly moved to the outer peripheral portion of the pulverizing table 2, or when unpulverized woody biomass or woody biomass having a predetermined particle size or more is repelled by the classifier, the outlet 6 In the case of falling to the outside, the woody biomass is not discharged out of the mill, but stays in the mill and causes an increase in the differential pressure in the mill, thereby increasing the power of the table driving device. Due to the increase in power of the table driving device, the pulverizing capacity of woody biomass is limited to about 10% of the pulverizing capacity of coal.

  As described above, when woody biomass is supplied to the vertical mill 1 or a mill having an equivalent structure and pulverized, the woody biomass of the mill behaves differently from coal and has a sufficient pulverization efficiency. There was a problem that it could not be obtained.

JP-A-10-28890 JP-A-2005-113125

  In view of such circumstances, the present invention impacts and crushes the woody biomass that has not been crushed by the pressure roller, thereby increasing the opportunity to crush the woody biomass, improving the crushing efficiency and increasing the crushing capacity. A biomass mill is provided.

  The present invention includes a housing forming a classification chamber, a classifier housed in an upper part of the housing, a grinding table housed in a lower part of the housing and driven to rotate by a table driving device, and pressed by the grinding table. A pressure roller unit having a pressure roller, a primary air chamber formed below the pulverization table, into which primary air is introduced, and primary air in the primary air chamber from the periphery of the pulverization table. A blowout port, a chute for supplying woody biomass to the center of the crushing table, and a rectifying function provided at a position facing the blowout port and inclined from the lower end toward the upper end so as to be separated from the chute The present invention relates to a biomass mill having a classification unit.

  Further, according to the present invention, the classification part with a rectifying function further includes a cylindrical part covering the periphery of the chute, and the cylindrical part reduces the flow passage cross section of the classification chamber. The pulverization capacity can be increased by actively discharging the pulverized woody biomass.

  According to the present invention, the classifier with a rectifying function further includes a reject chute that covers the classifier, and the reject chute is provided with slits at regular intervals in the circumferential direction. The woody biomass repelled by the above can be dropped on the pulverizing table without dropping outside the pulverizing table, and the pulverization efficiency can be improved.

  According to the present invention, the classifier further includes blades arranged at regular intervals in the circumferential direction, and the position where the slit is formed is a position facing the blade. Therefore, primary air can be effectively introduced, and classification efficiency and pulverization efficiency can be improved.

  Furthermore, according to the present invention, since the rectifying plate for rectifying the primary air toward the blade is provided in the slit, the flow of the primary air introduced into the classifier is rectified to reduce the pressure loss, thereby classifying. Efficiency and grinding efficiency can be further improved.

  According to the present invention, the housing forming the classification chamber, the classifier housed in the upper part of the housing, the grinding table housed in the lower part of the housing and driven to rotate by the table driving device, and the grinding table A pressure roller unit having a pressure roller to be pressed, a primary air chamber formed below the pulverization table, into which primary air is introduced, and a primary of the primary air chamber from the periphery of the pulverization table. A blowout opening for blowing air, a chute for supplying woody biomass to the center of the crushing table, and a rectification provided at a position opposite to the blowout opening so as to be inclined away from the chute from the lower end toward the upper end Since the functional classifying unit is provided, the woody biomass that has not been crushed by the pressure roller is caused to collide with the rectifying function classifying unit by primary air. Can, by chance grinding of wood-based biomass is carried out is increased, there is exhibited an excellent effect that pulverized is promoted can be increased to improve and milling capacity of grinding efficiency.

1 is a schematic sectional elevation view of a saddle mill according to a first embodiment of the present invention. It is a schematic sectional elevation view of a saddle mill according to a second embodiment of the present invention. It is a schematic elevation sectional drawing of the saddle-type mill which concerns on the 3rd Example of this invention. It is the elements on larger scale of the conventional vertical mill.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1, a first embodiment of the present invention will be described. In FIG. 1, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  A cylindrical housing 8 is erected on a base 7 having a hollow structure or a leg structure, and a sealed space is formed by the housing 8. A pulverization table 2 is provided in a lower portion of the space via a speed reducer 9, the speed reducer 9 is driven by a table drive motor 11, and the pulverization table 2 is rotated at a constant speed or a variable speed by the speed reducer 9. .

  A table segment 13 having a concave groove 12 having an arcuate cross section is provided on the upper surface of the grinding table 2.

  A required number of groups, for example, three groups of pressure roller units 14 are provided radially from the rotation center of the crushing table 2 at intervals of 120 °. The pressure roller unit 14 includes the pressure roller 3 and is tiltable about a pivot shaft 15. In addition, three sets of roller pressurizing devices 16 penetrating radially are provided below the housing 8. The roller pressure device 16 includes an actuator, for example, a hydraulic cylinder 17, and presses the pressure roller 3 against the concave groove 12 by the hydraulic cylinder 17.

  A primary air chamber 4 is formed below the pulverizing table 2, and a classification chamber 5 is provided above the pulverizing table 2 inside the housing 8.

  A primary air supply port 18 is attached to the lower part of the housing 8, and the primary air supply port 18 is connected to a blower (not shown) and communicates with the primary air chamber 4. Around the crushing table 2, a primary air outlet 6 that is inclined by θ ° is provided on the entire circumference so that the primary air is blown toward the center of the classification chamber 5. In addition, it is desirable that the inclination angle of the outlet 6 is formed in a range of 40 ° to 60 ° in the design of the vertical mill 1.

  A coal supply / discharge portion 19 is provided on the upper side of the housing 8, and a pipe-like chute 21 is provided so as to penetrate the center portion of the coal supply / discharge portion 19. The lower end is located above the center of the crushing table 2. The chute 21 is supplied with coal and woody biomass such as wood pellets, and the supplied coal and wood pellets fall to the center of the crushing table 2.

  A rotating tube 22 is fitted on the chute 21, and the rotating tube 22 is rotatably supported by a rotating tube support portion 23 via a bearing 24. The rotary tube 22 is provided with a pulley 25, a belt 27 is wound between the pulley 25 and the pulley 26, and the pulley 26 is fitted to the output shaft of the speed reducer 28. Thus, the rotary tube 22 is rotated by the classifier motor 29 via the speed reducer 28, the pulley 26, the belt 27, and the pulley 25.

  A blade 31 is attached to the rotary tube 22, and a classifier 32 is formed by the rotary tube 22, the pulley 25, the pulley 26, the belt 27, the speed reducer 28, the classifier motor 29, and the blade 31. It is configured.

  The blade 31 has a strip shape and is arranged on the inverted conical curved surface at a predetermined angular pitch in the circumferential direction. The blade 31 is inclined so as to be separated from the rotary tube 22 from the lower end toward the upper end, and is attached to the rotary tube 22 via a blade support portion 33.

  A classifying plate 34 that is a classifying unit with a rectifying function is attached to the chute 21 via a classifying plate support 35 at a position facing the outlet 6 below the classifier 32. The classification plate 34 is an inverted conical curved plate material that is inclined so as to be separated from the chute 21 from the lower end toward the upper end, and an opening 36 having a shape in which the tip of the cone is cut off is formed at the lower end. The diameter of the opening 36 is larger than the diameter of the chute 21. It is desirable that the classifying plate 34 be inclined at an angle that is orthogonal or substantially orthogonal to the primary air that is blown out from the outlet 6. The classification plate 34 may be a rectangular flat plate. In this case, the classification plate 34 is provided so as to be positioned between the pressure rollers 3 and 3.

  A pulverized coal feed pipe 37 for feeding the pulverized pulverized coal is connected to the coal feed / discharge unit 19, and the pulverized coal feed pipe 37 is connected to a boiler burner (not shown). Yes.

  Next, pulverization of wood pellets in the vertical mill 1 will be described as an example.

  In the figure, the solid line indicates the flow of primary air, and the dotted line indicates the flow of wood pellets.

  The pulverization table 2 is rotated by the table drive motor 11 via the speed reducer 9, and primary air at around 200 ° C. is introduced into the primary air chamber 4 from the primary air supply port 18. A wood pellet is introduced from the chute 21. The wood pellets flow from the lower end of the chute 21 to the center of the crushing table 2 and are supplied onto the crushing table 2.

  The wood pellets on the crushing table 2 are moved in the outer peripheral direction by the centrifugal force generated by the rotation of the crushing table 2 and are bitten by the pressure roller 3 so that the fine powder having a small particle diameter and the coarse powder having a large particle diameter are mixed. It is crushed into a body and further moved to the outer periphery by centrifugal force.

  At this time, the wood pellet is an object in which 1 to 2 mm of wood flour such as sawdust is pressed and compacted to about φ6 to 10 × L20 to 30 mm. 3, it moves between the pressure rollers 3 and 3 and moves to the outer periphery of the pulverizing table 2.

  The primary air introduced into the primary air chamber 4 from the primary air supply port 18 blows up from the outlet 6 of the pulverizing table 2 toward the center of the classification chamber 5 and is subjected to a table segment by centrifugal force. The powder exceeding 13 or the unpulverized wood pellets is blown up on the primary air blown from the outlet 6 and the primary air collides with the classification plate 34 to perform the primary classification. Is called.

  Unpulverized wood pellets having a large mass are impacted and crushed by colliding with the classification plate 34. The pulverized powder having a predetermined particle size or less is transported upward by the primary air, and the wood pellets and the coarse powder having a large particle size that have not been crushed even when colliding with the classification plate 34 have a rising force. Is dropped on the crushing table 2.

  Further, since the outlet of the primary air is only the pulverized coal feeding pipe 37, the primary air becomes an upward flow toward the pulverized coal feeding pipe 37 in the classification chamber 5, and the primary classified powder. Rises on the upward flow of primary air.

  The ejected primary air is deflected by being blocked by the classification plate 34, rises along the classification plate 34, and moves toward the wall surface of the housing 8. Therefore, the upward flow is not formed in the central portion of the classification chamber 5 but is formed in the vicinity of the inner wall of the housing 8. The classification plate 34 has not only the classification of wood pellets but also a function as a rectifying plate that rectifies the flow of primary air.

  The powder that rises along the inner wall surface of the housing 8 together with the primary air flows into the classifier 32, and is subjected to secondary classification so that the particle size is equal to or smaller than a predetermined particle size by the classifier 32, and finally classified. The fine powder having a predetermined particle size or less is fed from the pulverized coal feed pipe 37 and supplied to a burner of a boiler (not shown). Coarse powder larger than the predetermined particle size is bounced by the blade 31 (secondary classification) or falls by its own weight. Part of the coarse powder falls again on the grinding table 2, and part falls outside the grinding table 2. Of the fine powder having a predetermined particle size or less that has been secondarily classified by the classifier 32, the powder separated from the rising primary air passes through the lower end of the classifier 32, and the inclination of the classification plate 34. Along the center, and falls onto the crushing table 2 through the opening 36.

  The fallen powder moves to the concave groove 12 by the rotational centrifugal force of the crushing table 2, is pulverized again by the pressure roller 3, and is blown up by primary air. Further, the coarse powder that has passed between the pressure rollers 3 and 3 without being pulverized is blown up by primary air to collide with the classifying plate 34, and is crushed and primary classified again.

  As described above, in the first embodiment, the classifier 32 is provided below the classifier 32 by providing the classifier plate 34 that is orthogonal or substantially orthogonal to the primary air that is blown out from the outlet 6. Prior to classification, the wood pellets are crushed and primary classified by the classification plate 34.

  Therefore, the chances of the wood pellets being crushed and classified are increased, and the amount of coarse powder having a large particle diameter that rises on the primary air by the primary classification is reduced, so that the ventilation resistance is reduced. Further, since the coarse powder is bounced by the classification plate 34 immediately above the pulverization table 2 and immediately falls on the pulverization table 2, the opportunity to pulverize the coarse powder by the pressure roller 3 is increased, and the pulverization is performed. Efficiency is improved. Thus, it is possible to improve the grinding efficiency of the wood pellets and increase the grinding capacity.

  Next, referring to FIG. 2, a second embodiment of the present invention will be described. 2 that are the same as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  In the second embodiment, a rectifying cylinder 38, which is a classification section with a rectifying function, is provided below the classifier 32, instead of the classification plate 34 of the first embodiment.

  The flow straightening cylinder 38 has a hollow structure, and includes a cylindrical flow straightening portion 39 having an open upper end and a conical curved classification portion 41 that is inclined from the lower end toward the upper end so as to be separated from the chute 21. An opening 42 is formed at the lower end of the portion 41. The rectifying cylinder 38 is attached to the chute 21 via a rectifying cylinder support 43.

  The diameter of the rectifying unit 39 is the same as or substantially the same as the diameter of the lower end of the classifier 32, and the gradient of the classifying unit 41 is orthogonal to or substantially equal to the primary air blown out from the outlet 6 having an inclination of θ °. The diameter of the opening 42 is larger than the diameter of the chute 21, and a cylindrical opening is formed around the chute 21. In addition, it is desirable that the inclination θ of the classification unit 41 is set in a range of 40 ° to 60 ° with respect to the pulverization table 2 in the design of the vertical mill 1.

  When the processing is started, the wood pellets introduced from the chute 21 and flowing onto the crushing table 2 are crushed into fine powder and coarse powder by being caught in the pressure roller 3, or the Passes between the pressure rollers 3 and 3. Thereafter, it is moved to the outer periphery by the centrifugal force of the pulverizing table 2 and is blown up on the primary air blown up from the blow-out port 6 and collides with the classification part 41 of the rectifying cylinder 38 to perform primary classification. Is called.

  By colliding with the classification part 41, an impact was given to the wood pellet, and the wood pellet was crushed by the impact, and was not crushed even by the collision with the coarse powder having a large particle size and the classification part 41. The wood pellet falls on the grinding table 2 by its own weight.

  The primary air that has collided with the classifying unit 41 is deflected along the inclination of the classifying unit 41 and then rises, thereby generating an upward flow of primary air in the vicinity of the inner wall of the housing 8 and primary classification. The powder rises on the upward flow generated in the classification chamber 5.

  At this time, since the flow straightening cylinder 38 is present in the classification chamber 5, no upward flow of primary air is generated in the central portion of the classification chamber 5. Further, since the cross section of the flow path is reduced by the flow straightening portion 39 of the flow straightening cylinder 38, the flow path of the upward flow is narrowed and the flow velocity of the upward flow is increased.

  Secondary classification is performed on the powder rising on the inner wall surface of the housing 8 by the classifier 32, and fine powder having a predetermined particle size or less is sent out from the pulverized coal feed pipe 37, and a boiler (not shown) Supplied to the burner. Coarse powder having a predetermined particle size or more is bounced by the blade 31 or falls by its own weight. Part of the coarse powder falls again on the grinding table 2, and part falls outside the grinding table 2. Of the fine powder classified by the classifier 32, the fine powder separated from the rising primary air passes through the lower end of the classifier 32 and falls into the rectifying cylinder 38, and further, The particles are collected at the center by the classification unit 41 and fall onto the crushing table 2 through the opening 42.

  The fallen powder moves to the concave groove 12 by the rotational centrifugal force of the crushing table 2, is pulverized again by the pressure roller 3, and collides with the classification unit 41 by being blown up by primary air. Crushing and classification are performed again.

  As described above, in the second embodiment, below the classifier 32, the classification unit 41 orthogonal to or substantially orthogonal to the primary air blown from the outlet 6 and the flow of the upward flow of the primary air Since the rectifying cylinder 38 having the rectifying unit 39 for narrowing the path is provided, the classification unit 41 performs the pulverization and primary classification of the wood pellets before the classification by the classifier 32, and the classification unit The flow rate of the primary air that raises the fine coal classified to 41 is increased.

  Accordingly, the opportunity for pulverization and pulverization of the wood pellets is increased, the pulverization is promoted, and the primary air conveyance capacity is increased by the upward flow of the primary air with the increased flow velocity. Thus, the finely classified fine coal can be positively discharged from the pulverized coal feed pipe 37, and the efficiency of pulverizing the wood pellets in the vertical mill 1 and the increase of the pulverizing capacity can be achieved.

  Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the third embodiment, a rectifying cylinder 44 is provided below the classifier 32, and a reject chute 45 is provided so as to cover the periphery of the classifier 32, and the rectification is performed by the rectifying cylinder 44 and the reject chute 45. It constitutes a functional classifier.

  The rectifying cylinder 44 is substantially the same structure as the rectifying cylinder 38 in the second embodiment, has a rectifying section 46 and a classification section 47, and is attached to the chute 21 via a rectifying cylinder support section 49. Yes.

  Around the classifier 32, a hollow, inverted frusto-conical reject chute 45 having the same inclination as the classifier 32 is disposed. A slit 51 is formed in the reject chute 45 at a predetermined angular pitch in the circumferential direction at a position facing the blade 31 of the classifier 32 so that primary air containing powder passes through the slit 51. It has become. A rectifying plate 52 may be provided in the slit 51 so that primary air passing through the slit 51 faces the blade 31. The outer shape of the slit 51 is a rectangle, but it may be a trapezoid whose upper side is longer than the lower side.

  The reject chute 45 has an upper end fixed to the housing 8 and a lower end fixed to the rectifying cylinder 44 by welding or the like and supported.

  When the processing is started, the wood pellets introduced from the chute 21 and flowing onto the crushing table 2 are crushed into fine powder and coarse powder by being caught in the pressure roller 3, or the Passes between the pressure rollers 3 and 3. After that, the crushing table 2 moves to the outer periphery due to the centrifugal force, rides on the primary air blown up from the blowout port 6, and collides with the classifying portion 47 of the rectifying cylinder 44 to perform primary classification. Is called.

  The primary air that has collided with the classifying portion 47 is deflected along the inclination of the classifying portion 47 and rises to generate an upward flow of primary air in the vicinity of the inner wall of the housing 8. The powder rises on the upward flow generated in the classification chamber 5.

  At this time, since the flow straightening tube 44 exists in the classification chamber 5, no upward flow of primary air is generated in the central portion of the classification chamber 5. Further, since the flow passage cross section is reduced by the flow straightening portion 46 of the flow straightening cylinder 44, the flow flow of the upward flow is narrowed and the flow velocity of the upward flow is increased.

  The powder that has moved up the inner wall surface of the housing 8, crossed the slit 51, and entered the reject chute 45 is subjected to secondary classification by the classifier 32, and the fine powder moves the blade 31. It is sent out from the crushed pulverized coal feed pipe 37 and supplied to a burner of a boiler (not shown). When the rectifying plate 52 is provided in the slit 51, the primary air that crosses the slit 51 is rectified so as to cross the blade 31.

  Coarse powder having a predetermined particle size or more falls on the pulverizing table 2 by its own weight or is repelled by the blade 31, and the repelled coarse powder slides along the slope of the reject chute 45, and the rectification is performed. It passes through the inside of the tube 44, is brought close to the center by the classifying portion 47, and falls onto the pulverizing table 2 through the opening 48. Further, among the powders secondarily classified by the classifier 32, the fine powder separated from the rising primary air passes through the lower end of the classifier 32 and passes on the pulverizing table 2 from the opening 48. Fall.

  The fallen powder is moved to the outer periphery by the rotational centrifugal force of the crushing table 2, pulverized again by the pressure roller 3, blown up by primary air, collides with the classification unit 47, and is re-dissolved. Crushing and classification are performed.

  As described above, in the third embodiment, below the classifier 32, the classification unit 47 orthogonal to or substantially orthogonal to the primary air blown from the outlet 6 and the flow of the upward flow of the primary air Since the rectifying cylinder 44 having the rectifying unit 46 for narrowing the path is provided, the classification unit 47 performs pulverization and primary classification of the wood pellets before classification by the classifier 32, and the classification unit The flow rate of the primary air that raises the powder classified to 47 is increased.

  Therefore, the opportunity for the pulverization and pulverization of the wood pellets is increased, the pulverization is promoted, and the upward flow of the primary air whose conveying capacity is increased by increasing the flow rate is increased by the classifying unit 47. The finely classified fine coal can be positively discharged from the pulverized coal feed pipe 37.

  Further, since the reject chute 45 having the slit 51 perforated at a position facing the blade 31 and the rectifying plate 52 provided in the slit 51 is provided around the classifier 32, the blade 31 The powder bounced by the nozzle can be dropped onto the crushing table 2 along the slope of the reject chute 45, and the slit 51 and the rectifying plate 52 can flow primary air before the classifier 32. The primary air can be effectively introduced into the classifier 32.

  In addition, the reject chute 45 separates the upward flow that rises in the vicinity of the inner wall of the housing 8 and the downward flow that descends the central portion of the classification chamber 5, thereby eliminating collision and interference between the upward flow and the downward flow. And pressure loss can be reduced.

  Further, the powder bounced by the blade 31 can be dropped onto the crushing table 2 without dropping out of the crushing table 2, and the powder bounced by the blade 31 does not interfere with the upward flow. The pressure loss in the classification chamber 5 can be reduced, the efficiency of pulverization of the wood pellets in the vertical mill 1 and the increase of the pulverization capacity, and the improvement of the powder classification efficiency. Can do.

DESCRIPTION OF SYMBOLS 1 Vertical mill 2 Crushing table 3 Pressure roller 4 Primary air chamber 5 Classifying chamber 6 Outlet 8 Housing 21 Chute 31 Blade 32 Classifier 34 Classifying plate 38 Rectifier cylinder 39 Rectifier 41 Classifier 44 Rectifier cylinder 45 Reject chute 46 Rectifier 47 Classifier 51 Slit

Claims (5)

  A housing forming a classification chamber, a classifier housed in an upper part of the housing, a grinding table housed in a lower part of the housing and driven to rotate by a table driving device, and a pressure roller pressed against the grinding table A pressure roller unit including: a primary air chamber formed below the pulverization table into which primary air is introduced; and a blow-out port for blowing out primary air in the primary air chamber from the periphery of the pulverization table And a chute for supplying woody biomass to the center of the crushing table, and a classifier with a rectifying function provided at a position opposite to the outlet from the lower end toward the upper end so as to be separated from the chute. A biomass mill characterized by comprising.   The biomass mill according to claim 1, wherein the classification unit with a rectifying function further includes a cylindrical part that covers the periphery of the chute, and the cylindrical part reduces the cross-section of the flow path of the classification chamber.   The biomass mill according to claim 2, wherein the classification unit with a rectifying function further includes a reject chute that covers the periphery of the classifier, and slits are formed in the reject chute at regular intervals in the circumferential direction.   4. The biomass mill according to claim 3, wherein the classifier further includes blades arranged at regular intervals in the circumferential direction, and the position where the slit is formed is a position facing the blade.   The biomass mill according to claim 4, wherein a rectifying plate that rectifies primary air toward the blade is provided in the slit.

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