WO2019059063A1

WO2019059063A1 - Biomass mill

Info

Publication number: WO2019059063A1
Application number: PCT/JP2018/033806
Authority: WO
Inventors: 洋輔大西; 相澤　孝; 淳鹿島; 豊竹野; 光輝松▲崎▼; 祐樹近藤; 浩明金本
Original assignee: 三菱日立パワーシステムズ株式会社
Priority date: 2017-09-19
Filing date: 2018-09-12
Publication date: 2019-03-28
Also published as: JP6500066B2; KR20200005616A; CN110740815A; PH12020500196A1; JP2019051500A; TW201919764A; KR102302031B1; CN110740815B; TWI687261B

Abstract

Provided is a biomass mill that can efficiently and safely grind woody biomass. An internal wall 12 is placed in the interior of a housing 11 in which a rotating table 3, a grinding roller 4, and a rotary classifier 6 are built. An annular channel 13 for guiding, to the rotary classifier 6, biomass particles blown up by primary air is formed between an inner surface of the housing 11 and an outer surface of the internal wall 12. The internal wall 12 does not return coarse particles C repelled by the rotary classifier 6 to the rotating table 3 but returns the same to the annular channel 13, thus causing the annular channel 13 to function as a gravitational classifier. Due to this configuration, large amounts of woody biomass are prevented from being deposited on the rotating table 3.

Description

Biomass mill

The present invention relates to a biomass mill that pulverizes woody biomass to produce biomass particles that can be used as boiler fuel.

In recent years, as a biomass mill of this type, a housing that forms a classification chamber, a classifier provided in the upper part of the classification chamber, and a crushing table provided in the lower part of the classification chamber and driven by a table drive device A plurality of pressure roller units each having a pressure roller pressed against the crushing table, an outlet for ejecting primary air from the periphery of the crushing table, and a chute for supplying woody biomass to the center of the crushing table And a contraction portion, wherein the contraction portion includes an inner contraction portion surrounding the chute, and an outer contraction portion provided at a position facing the inner contraction portion on the inner peripheral surface of the housing. A frusto-conical portion in which a contraction flow channel is formed between the inner contraction section and the outer contraction section, and the inner contraction section extends upward from an upper end of the contraction channel; Below the upper end of the truncated cone Having a inverted truncated cone section which output has been proposed (e.g., see Patent Document 1.).

According to Patent Document 1, since the conventional biomass mill is configured as described above, the powder flow in the wood-based biomass is accelerated through the contraction portion, so that the powder in the classification chamber Residence time is shortened, so that the rise of the mill differential pressure is suppressed and the grinding capacity can be increased, the deposition of the powder on the inner contraction portion is prevented, and the powder is prevented from remaining in the classification chamber Safety can be improved. Moreover, according to Patent Document 1, it is supposed that the biomass mill can be implemented at low cost without major improvement or equipment change by using a pulverizer based on a coal mill for pulverizing coal.

JP, 2017-47383, A

However, in the conventional biomass mill, a contraction flow portion having a contraction flow passage capable of passing only biomass particles crushed to a size of about 1 to 2 mm is formed between the grinding table and the classifier. With regard to coarse-grained particles with large particle size and woody biomass blown up by primary air without being crushed, it is made to collide with the lower surface of the constriction part, separated from the powder flow, and dropped again onto the grinding table It has become.

For this reason, in the conventional biomass mill, a large amount of woody biomass tends to be accumulated on the grinding table, and it is difficult to efficiently produce the intended biomass particles, and the pressure loss in the mill and the grinding power of woody biomass are also It is easy to increase. Further, in the conventional biomass mill, a large amount of woody biomass tends to be accumulated on the grinding table, so the volatile components contained in the woody biomass are likely to have a high concentration in the mill, and ignition in the mill is also concerned. Thus, conventional biomass mills have room for further improvement in these respects.

Then, an object of the present invention is to provide a biomass mill capable of grinding woody biomass efficiently and safely.

In order to achieve the above object, according to a typical present invention, a rotary table disposed at a lower portion of a housing, a grinding roller for grinding woody biomass between the rotary table, the rotary table, and the housing A primary chute outlet provided between the two, a center chute for supplying woody biomass which is a raw material to the center of the upper surface of the rotary table, a rotary classifier disposed at the upper part of the housing, and the housing The rotary classifier comprises a cylindrical inner wall disposed inside the inner wall of the housing, an inner surface of the housing, and an outer surface of the inner wall, the powder flow blown up by the primary air jetted from the outlet. And the inner wall is provided with the rough particles of woody biomass that has not passed through the rotary classifier, Characterized in that it is configured to return only the road.

According to the present invention, the biomass particles crushed between the rotating table and the grinding roller can be efficiently discharged to the outside of the mill, so that the pressure loss in the mill and the grinding power of the wood-based biomass can be suppressed. It can grind and process woody biomass safely. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the whole structure of the vertical biomass mill which concerns on embodiment. It is a perspective view showing an important section of a vertical biomass mill concerning an embodiment. It is a perspective view which shows the structure of the internal wall with which the vertical biomass mill which concerns on embodiment is equipped. It is a graph which shows the grinding | pulverization motive power value of the vertical biomass mill which concerns on embodiment by a relative value with a prior art. It is a graph which shows the pressure loss value of the vertical biomass mill which concerns on embodiment by a relative value with a prior art. It is a graph which compares and shows the grinding | pulverization power characteristic and pressure loss characteristic with respect to the biomass supply load of the vertical biomass mill which concerns on embodiment, and a prior art.

Hereinafter, the embodiment of the biomass mill according to the present invention will be described by taking a vertical biomass mill as an example. The embodiment described below shows a specific example when carrying out the present invention, and the scope of the present invention is not limited to the embodiment described below. In addition, crushing of woody biomass, particularly woody pellets to obtain biomass particles is generally referred to as "crushing", but in the present specification, it is referred to as "crushing" following the example of a coal mill.

FIG. 1 is a cross-sectional view showing an entire configuration of a vertical biomass mill according to an embodiment. As is clear from this figure, the vertical biomass mill 1 according to the embodiment uses woody biomass which is a raw material between the rotary table 3 rotationally driven in the horizontal plane by the table driving device 2 and the rotary table 3. A grinding roller 4 for crushing and producing biomass particles as an object, a center chute 5 disposed above the rotary table 3 and supplying woody biomass to the center of the upper surface of the rotary table 3, an outer periphery of the center chute 5 , A stationary classifier 7 disposed on the outer periphery of the rotational classifier 6, a bounce plate 8 disposed on the outer periphery of the stationary classifier 7, a rotational classifier 6 and a stationary classifier And a distribution unit 9 for conveying the biomass particles classified in 7 to a predetermined supply destination.

The rotary table 3, the grinding roller 4, the rotary classifier 6 and the fixed classifier 7 are accommodated in a cylindrically formed housing 11, and the upper end of the housing 11 is connected to the distribution unit 9. . In addition, an internal wall 12 for preventing the return of coarse particles from the rotary classifier 6 and the fixed classifier 7 to the rotary table 3 is disposed between the grinding roller 4 and the rotary classifier 6 concentrically with the housing 11. ing. Thereby, between the inner surface of housing 11 and the outer surface of inner wall 12, annular channel 13 which is a channel of a powder stream containing biomass particles is formed.

Between the outer peripheral surface of the rotary table 3 and the inner surface of the housing 11, a primary air outlet 15 provided with a rotary throat vane 14 is provided. The primary air is supplied from the primary air duct 16, the flow velocity and the wind direction are adjusted by the rotary throat vanes 14, and the primary air is injected from the outlet 15 into the housing 11. In the vertical biomass mill 1, the primary air temperature is adjusted to, for example, 150 ° C., which is lower than that of the coal mill.

A ring-shaped recessed groove 3 a having a width capable of receiving the grinding roller 4 is formed on the upper surface of the rotary table 3 concentrically with the rotation center of the rotary table 3. Therefore, when the rotary table 3 is rotationally driven by the table driving device 2, the grinding roller 4 is rolled in the concave groove 3a, whereby the wood-based biomass which is the raw material is crushed and the biomass particles which are the target are manufactured. Ru.

Various types of wood-based biomass can be used, but by crushing, biomass particles with a uniform size of about 1 mm to 2 mm can be obtained. Is particularly preferred.

The grinding roller 4 is rotatably attached to the roller bracket 21, and the roller bracket 21 is supported by the pressure frame 23 via the roller pivot 22. The pressing frame 23 is connected to the pressing rod 26 of the pressing cylinder 25 whose one end is connected to a predetermined fixing portion via the pressing arm 24. Therefore, the grinding roller 4 is moved up and down through the pressure rod 26, the pressure arm 24, the pressure frame 23, the roller pivot 22 and the roller bracket 21 by driving the pressure cylinder 25, thereby The grinding load acting between the rotary table 3 and the grinding roller 4 is adjusted. The grinding roller 4 is provided in the circumferential direction of the rotary table 3 in plurality (in many cases, three).

In addition, the aspect of the above-mentioned grinding | pulverization is an example, Comprising: This invention is not limited to this. The form of the pulverizer is not limited to a roller, and may be a ball. Also in the mode of pressurization, as long as the crusher is pushed downward and the crushing load acts on the concave groove 3a, such as the rotation shaft of the roller, the operation of the component and each element is irrelevant.

The center chute 5 has an upper end attached to the distribution unit 9 and a lower end inserted into the inner wall 12.

The rotary classifier 6 is configured by arranging a large number of fins 6a at predetermined intervals in the circumferential direction, and classification of biomass particles is performed by rotationally driving these fins 6a with a motor (not shown). It is supposed to be. The particle size distribution of the biomass particles is adjusted by the number of revolutions of the fins 6a. In the rotary classifier 6 according to the embodiment, the bottom plate is a fin support annular plate 6 b for raising the fins 6 a. The rotary classifier 6 has a function of evenly distributing biomass particles to each of a plurality of (only one is shown in FIG. 1) transport pipes 9a provided in the distribution unit 9.

The fixed classifier 7 has a large number of non-rotating fins arranged at predetermined intervals in the circumferential direction, and classifies biomass particles in the powder flow by applying powder flow to the fins.

The bounce plate 8 bounces the biomass particles blown up above the rotary classifier 6 and the fixed classifier 7 through the inside of the annular channel 13 and guides the biomass particles to the rotary classifier 6 and the fixed classifier 7. It also functions as a contraction member for adjusting the flow rate of the powder flow flowing into the machine 6 and the fixed classifier 7. The flow velocity of the powder flow flowing into the rotary classifier 6 and the fixed classifier 7 is adjusted to, for example, about 10 m / sec by the bounce plate 8.

The distribution unit 9 is provided with a transfer pipe 9 a for transferring the biomass particles produced by the vertical biomass mill 1 to a predetermined transfer destination. As a transfer destination of biomass particles, there are a biomass-combustion boiler or a biomass-combustion boiler that mixes and burns wood-based biomass and coal. In addition, when the distribution part 9 is equipped with the several conveyance pipe 9a, in order to equalize introduction of the biomass particle | grains in each conveyance pipe 9a, the structure which makes the edge part of the conveyance pipe 9a project in the distribution part 9 It can also be done.

The housing 11 is formed in a cylindrical shape that can accommodate the rotary table 3, the grinding roller 4, the rotary classifier 6, the fixed classifier 7 and the bounce plate 8, but in order to facilitate maintenance of the vertical biomass mill 1, For example, it can also be configured with a combination of a plurality of members that can be disassembled, such as the upper housing, the middle housing, and the lower housing.

As shown in FIG. 2 and FIG. 3, the inner wall 12 extends from the upper end portion to which the ring member 31 is attached to the ring member 31 disposed opposite to the fin support annular plate 6 b of the rotary classifier 6 downward. Therefore, it comprises an upper conical portion 32 having a larger diameter, a cylindrical portion 33 connected to the lower end of the upper conical portion 32, and a plurality of detachable plates 34 detachably connected to the lower end of the cylindrical portion 33. ing.

The internal wall 12 is disposed between the rotary table 3 and the rotary classifier 6 inside the housing 11, as shown in FIG. The inner wall 12 is attached to the housing 11 using a fixing member (not shown) extending from the inner surface of the housing 11. A slight clearance d is provided between the fin support annular plate 6 b and the ring member 31 in order to prevent interference between the rotary classifier 6 and the inner wall 12. The size of the clearance d is set to about 2 mm to 8 mm in order to keep the flow path resistance of the flow path from the inside to the outside of the inner wall 12 large. Thereby, it is possible to prevent the biomass particles from invading between the fin support annular plate 6 b and the ring member 31, and to prevent galling of the fin support annular plate 6 b and the ring member 31 by the biomass particles.

A pressure arm through hole 35 for penetrating the pressure arm 24 is formed in the cylindrical portion 33, and a maintenance door 36 for enabling loading and unloading of the grinding roller 4 during maintenance can be opened and closed. Be equipped. Thus, by forming the pressure arm through hole 35 in the cylindrical portion 33, the installation of the inner wall 12 in the housing 11 becomes possible. Further, by providing the maintenance door 36 in the cylindrical portion 33, replacement of the grinding roller 4 at the time of maintenance becomes possible.

The detachable plate 34 is attached to the cylindrical portion 33 after the pressure arm 24 penetrates into the pressure arm through hole 35, and an access door 37 which a person enters and leaves at the time of maintenance is opened and closed in part thereof. It is equipped to be possible. Thus, by configuring the cylindrical portion 33 and the detachable plate 34 as separate members, the installation of the inner wall 12 in the housing 11 becomes possible. Further, by providing the access door 37 on the desorption plate 34, the operator can enter the vertical biomass mill 1 and maintenance of the grinding roller 4 and the like can be performed.

In addition, the desorption plate 34 has a function of guiding the biomass particles blown up by the primary air into the annular channel 13. For this reason, the detachable plate 34 is disposed on the outer peripheral side of the grinding roller 4 so as to overlap at least a part of the grinding roller 4, and more preferably the lower end portion covers up to a lower portion than the rotation center of the grinding roller 4 Configured as.

Hereinafter, the operation and effects of the biomass mill 1 according to the embodiment configured as described above will be described.

The woody biomass A supplied from the center chute 5 falls to the center of the rotary table 3 as shown by the arrow in FIG. 1 and then spirals on the rotary table 3 by the centrifugal force accompanying the rotation of the rotary table 3 It moves to the outer peripheral part by drawing the locus of and enters into the concave groove 3a. The wood-based biomass A that has entered the inside of the concave groove 3a is bitten between the rotary table 3 and the grinding roller 4 in the form of a tire and is ground to become biomass particles.

The produced biomass particles are blown up while being dried by the primary air blown out into the housing 11 from the outlet 15 and are introduced into the annular channel 13 as a powder flow B containing biomass particles. Ru. The powder flow B moves upward while spirally rotating in the annular flow passage 13, and the flow passage along the upper conical portion 32 provided on the inner wall 12 is on the rotary classifier 6 and fixed classifier 7 side. Change to

Among biomass particles having passed through the annular flow channel 13, biomass particles of the appropriate size directly enter the distribution unit 9 through the rotary classifier 6 or the fixed classifier 7. Further, among the biomass particles that have passed through the annular flow channel 13, the fine particles hit the bounce plate 8 and then enter the distribution unit 9 through the rotary classifier 6 or the fixed classifier 7. On the other hand, among the biomass particles having passed through the annular flow channel 13, the coarse particles C can not pass through the rotary classifier 6 or the fixed classifier 7, and are guided by the upper conical portion 32 provided on the inner wall 12 It returns to the annular flow path 13.

The coarse particles returned into the annular flow channel 13 move up and down in the annular flow channel 13 due to the balance between their own weight and the blowing-up force of the primary air, and they are finely crushed in the meantime, eventually the rotary classifier 6 or fixed. It enters into the distribution unit 9 through the classifier 7. That is, the annular flow path 13 functions as a gravity classifier of biomass particles.

Thus, the vertical biomass mill 1 according to the embodiment is provided with the inner wall 12 between the rotary table 3 and the rotary classifier 6, and the coarse particles C which do not pass through the rotary classifier 6 or the fixed classifier 7 Is returned into the annular flow passage 13 formed between the inner surface of the housing 11 and the outer surface of the inner wall 12, so that the coarse particles C can be prevented from returning onto the rotary table 3. That is, the vertical biomass mill 1 according to the embodiment has a one-through structure in which biomass particles crushed between the rotary table 3 and the grinding roller 4 are discharged to the distribution unit 9 through only the annular flow channel 13 Therefore, the coarse particles C can be reliably prevented from returning onto the rotary table 3.

Therefore, according to the vertical biomass mill 1 of the embodiment, since the wood-based biomass A more than the amount set in advance is not retained on the rotary table 3, the power required to crush the wood-based biomass can be suppressed and the mill Internal pressure loss can also be suppressed. Furthermore, according to the vertical biomass mill 1 of the embodiment, the concentration increase of volatile components in the mill can also be prevented.

The grinding | pulverization power value of the vertical biomass mill 1 which concerns on embodiment in FIG. 4 is shown compared with the conventional vertical biomass mill which is not equipped with the internal wall 12. FIG. In this graph, the grinding power value of the vertical biomass mill 1 according to the embodiment is shown as a relative value when the grinding power value of the conventional vertical biomass mill is “1”. In the conventional vertical biomass mill, a large amount of wood-based biomass A tends to stay on the rotary table 3, and when a large amount of wood-based biomass A stays on the rotary table 3, the crushing power increases rapidly. It is difficult to raise Therefore, in FIG. 4, the comparison is made at the time of comparable low load operation.

The crushing power varies widely depending on the type of woody biomass as the raw material and the operating conditions of the mill, but according to the data of FIG. 4, the crushing power value of the vertical biomass mill 1 according to the embodiment is the conventional vertical shape. It is 0.42 to 0.63 times the grinding power value of the biomass mill. From this data, it can be said that the vertical biomass mill 1 according to the embodiment can significantly suppress the grinding power as compared with the conventional vertical biomass mill.

The pressure loss value of the vertical biomass mill 1 according to the embodiment is shown in FIG. 5 in comparison with a conventional vertical biomass mill without the internal wall 12. Also in this graph, the pressure loss value of the vertical biomass mill 1 according to the embodiment is shown as a relative value when the pressure loss value of the conventional vertical biomass mill is "1". In addition, it is a comparison at the time of comparable low load operation.

The pressure loss in the mill also varies widely depending on the type of woody biomass that is the raw material and the operating conditions of the mill, but according to the data in FIG. 5, the pressure loss value of the vertical biomass mill 1 according to the embodiment is The pressure drop value of the vertical biomass mill is 0.37 to 0.67 times. From this data, it can be said that the vertical biomass mill 1 according to the embodiment can significantly suppress the pressure loss as compared with the conventional vertical biomass mill.

In FIG. 6, the grinding | pulverization power characteristic and pressure loss characteristic with respect to biomass supply load of the vertical biomass mill 1 which concerns on embodiment, and the conventional vertical biomass mill which is not equipped with the internal wall 12 are compared and shown. As is clear from this data, the vertical biomass mill 1 according to the embodiment has stable grinding power characteristics and pressure loss characteristics against fluctuations in biomass supply load, and a wide range of operation from low load to high load Is possible. In contrast, conventional vertical biomass mills can only operate at low loads. From this data, it can be said that the vertical biomass mill 1 according to the embodiment is capable of high-load operation and has a high ability to produce biomass particles.

The vertical biomass mill 1 of the present invention is characterized in that an inner wall 12 for restricting the return of coarse particles C to the rotary table 3 is installed in the housing 11, and the other parts are the same as above. The present invention is not limited to the embodiment, and can be changed as appropriate. For example, the vertical biomass mill 1 of the present invention can be configured by modifying a conventionally known coal mill, but is not limited thereto. Moreover, although only wood-based biomass is crushed in the embodiment, coal and wood-based biomass can also be mixed and crushed. According to the vertical biomass mill 1 of the present invention, when coal and woody biomass are mixed and crushed, woody biomass can be mixed at a high ratio.

In the vertical biomass mill 1 of the present invention, since the inner wall 12 is configured to be removable from the housing 11, the inner wall 12 is removed from the housing 11 and rotational classification is performed on the lower portion of the rotary classifier 6. It can also be used as a coal mill by providing a hopper for returning coarse particles C which have not passed through the machine 6 or the fixed classifier 7 to the central portion of the rotary table 3.

DESCRIPTION OF SYMBOLS 1 ... Vertical biomass mill, 2 ... Table drive device, 3 ... Rotating table, 3a ... Ditch | groove, 4 ... Crushing roller, 5 ... Center chute, 6 ... Rotational classification machine, 6a ... Fin, 6b ... Fin support ring board 7, 7: fixed classifier, 8: bounce plate, 9: distribution unit, 9a: transport pipe, 11: housing, 12: internal wall, 13: annular flow passage, 14: rotational throat vane, 15: primary air blowout Port 16 16 Primary air duct 21 Roller bracket 22 Roller pivot 23 Pressure frame 24 Pressure arm 25 Pressure cylinder 26 Pressure rod 31 Ring member 32 Upper conical part, 33: cylindrical part, 34: desorption plate, 35: pressure arm through hole, 36: maintenance door, 37: access door, A: woody biomass, B: powder flow, C: coarse particles

Claims

A rotary table arranged at the lower part of the housing, a grinding roller for grinding woody biomass between the rotary table, a primary air outlet for outlet provided between the rotary table and the housing, and A center chute for supplying woody biomass which is a raw material to the upper surface center of a rotary table, a rotary classifier disposed at the upper part of the housing, a cylindrical inner wall disposed inside the housing, and the housing And an annular flow path for guiding a powder flow blown up by primary air jetted from the outlet to the rotary classifier.
A biomass mill characterized in that the inner wall is configured to return coarse particles of woody biomass that has not passed through the rotary classifier only to the annular flow channel.
The inner wall has a ring member disposed opposite to the rotary classifier, an upper conical portion whose diameter increases from the upper end to which the ring member is attached to the lower side, and a lower end of the upper conical portion The biomass mill according to claim 1, characterized by comprising: a cylindrical portion to be connected; and a plurality of detachable plates detachably connected to the lower end portion of the cylindrical portion.
The biomass mill according to claim 2, wherein the cylindrical portion includes a maintenance door capable of carrying in and out of the grinding roller.
The biomass mill according to claim 2, wherein the desorption plate comprises an access door which can be accessed by a person.
The inner wall is detachably attached to the housing between the upper surface of the ring member and the lower end of the rotary classifier via a required clearance capable of preventing biting of wood-based biomass. The biomass mill according to claim 2, characterized in that.
The biomass mill according to claim 2, wherein the desorption plate is disposed on an outer peripheral side of the grinding roller so as to overlap with a part of the grinding roller.
The biomass mill according to claim 6, wherein the desorption plate is configured such that a lower end portion of the desorption plate covers a lower portion than a rotation center of the grinding roller.
The biomass mill according to claim 1, further comprising a contraction member for increasing the flow velocity of the powder flow flowing into the rotary classifier on an outer peripheral portion of the rotary classifier.