JP2007185569A - Vertical type roller mill and pulverizing method using vertical type roller mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical type roller mill capable of making a pulverization roller and a pulverization table stably bite an object to be pulverized even when a moisture content of the object to be pulverized is not suitable. <P>SOLUTION: In the pulverizing method using the vertical type roller mill, the object to be pulverized fed to the vertical type roller mill from the outside is firstly sorted to a normal object N to be pulverized having a particle diameter less than a predetermined first particle diameter and a bulky object M to be pulverized having a particle diameter of the first particle diameter or more. Nextly, while the normal object N to be pulverized is fed onto the rotating pulverization table 22, the pulverization table 22 and the pulverization roller 23 are made to bite the normal object N to be pulverized to perform pulverization. Then, when the generation of a biting failure of the normal object N to be pulverized between the pulverization table 22 and the pulverization roller 23 is detected during the pulverization step, the bulky object M to be pulverized is added/fed onto the rotating pulverization table 22 and a mixture of the normal object N to be pulverized and the bulky object M to be pulverized is bitten between the pulverization table 22 and the pulverization roller 23 to perform pulverization. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vertical roller mill and a pulverizing method using the same, and more particularly to a vertical roller mill for stabilizing the biting of an object to be pulverized between a pulverizing roller and a pulverizing table, and a pulverizing method using the vertical roller mill.

  The pulverized coal machine is a device for pulverizing and pulverizing a material to be crushed, such as petroleum coke, which is boiler fuel of a thermal power generation facility, before supplying it to the boiler. By pulverizing fuel such as petroleum coke with this pulverized coal machine, fuel in a state of being easily pulverized and combusted can be supplied to the boiler.

  A vertical roller mill is used as a pulverizer for pulverizing an object to be pulverized like the pulverized coal machine. The vertical roller mill includes a crushing table that rotates in a horizontal plane, and a plurality of crushing rollers that are pressed on the crushing table and rotate following the rotation of the crushing table. The material to be crushed can be bitten into the pulverized portion between the two and crushed.

  However, in the vertical roller mill that pulverizes the object to be pulverized such as solid fuel in this way, there is a case in which the fuel (object to be pulverized) is poorly caught in the pulverizing portion between the pulverizing table and the pulverizing roller. This poor biting is a phenomenon in which the fuel supplied on the crushing table slips without being bitten between the crushing table and the crushing roller, resulting in vibrations in the crushing part. . When such a biting failure occurs, the crushing function of the vertical roller mill as a pulverized coal machine is not performed, so that there is a problem that fuel is not supplied to the boiler and power generation stops.

  As a technique related to such a biting failure of the object to be pulverized, for example, in Patent Document 1, before starting operation of the vertical roller mill, the object to be pulverized is stored in an optimum state on the pulverization table. It describes that the vertical roller mill is started in a state where the pulverizing roller is not pressurized, and the pulverizing roller is pressurized after the operation is stabilized.

JP-A-5-269365

  However, as a result of intensive studies by the inventors of the present application, in a vertical roller mill, when the moisture content of the material to be pulverized is not within the range suitable for pulverization, for example, the moisture content of the pulverized fuel is less than 4% by mass and dried. If the water content is greater than 11% by mass and the water content is high, the grinding between the grinding table and the grinding roller is necessary when starting up the vertical roller mill or changing the fuel supply amount. It was found that poor fuel biting (slip, vibration) was likely to occur in the part. That is, when the amount of water in the fuel is high and low, the frictional resistance for biting between the crushing roller and the crushing table becomes small, so that the fuel cannot slip into the crushing part and slips. As a result, a clean bed of fuel cannot be formed on the crushing table, so that a slip phenomenon occurs between the crushing table and the crushing roller, and vibration is generated in the crushing unit.

  Thus, when the moisture content of the material to be crushed is not appropriate (for example, when the moisture content of the fuel is less than 4% by mass or greater than 11% by mass), as in the technique of Patent Document 1 above, Even if the object to be crushed is stored in an optimum state on the crushing table before the start of the operation of the vertical roller mill, there is a problem that it is impossible to prevent the occurrence of biting failure after the start of operation. Further, the above-described prior art has a problem that it is not possible to suppress the biting failure (slip of the object to be crushed, vibration of the apparatus, etc.) that occurred during the pulverizing operation of the object to be crushed.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a space between the grinding roller and the grinding table even when the water content of the material to be ground is not suitable. It is an object of the present invention to provide a new and improved vertical roller mill capable of stably biting an object to be ground and a grinding method using the same.

  In order to solve the above problems, according to an aspect of the present invention, there is provided a crushing table provided with a crushing table that rotates in a horizontal plane, and a plurality of crushing rollers that are arranged on the crushing table at predetermined intervals along the rotation direction. A grinding method using a mold roller mill is provided. This pulverization method includes a selection step of selecting a pulverized material supplied from the outside to a vertical roller mill into a normal pulverized material having a particle size smaller than a predetermined first particle size and a massive pulverized material having a particle size larger than the first particle size. A pulverizing step in which the object to be pulverized is caught between the pulverizing table and the pulverizing roller while the object to be pulverized is normally supplied onto the rotating pulverizing table. Then, during the pulverization process, when it is detected that the normal pulverized object is caught between the pulverizing table and the pulverizing roller, the crushed object is additionally supplied onto the rotating pulverizing table. A mixture of the object to be pulverized and the mass to be pulverized is usually sandwiched between the pulverizing rollers and pulverized.

  With this configuration, in the pulverization process, the normal pulverized material having a particle size of less than the first particle size is supplied and pulverized at the normal time when no biting failure occurs. In addition, a mass to be pulverized having a particle size equal to or greater than the first particle size is supplied, and a mixture of the material to be pulverized and the mass to be pulverized is usually bitten and pulverized. Thereby, a massive pulverized object having a high biting resistance with respect to the pulverizing table and the pulverizing roller can be suitably entrapped, the pulverizing roller can be lifted, and the pulverized object can be normally entrained. Therefore, even if the water content of the object to be pulverized is not suitable, the object to be pulverized can be squeezed between the pulverizing roller and the pulverizing table and pulverized, and the fine powder of the object to be pulverized can be stably supplied.

  Further, a vibration value indicating the magnitude of vibration generated in the vertical roller mill in the pulverization step is detected, and when the detected vibration value is equal to or greater than a predetermined reference vibration value set in advance, or in the pulverization step A load value representing the load of the driving device that rotates the table is detected, and when the detected load value is equal to or less than a predetermined reference load value that is set in advance, it is determined that the biting failure of the object to be crushed has occurred. You may make it do. Thereby, it is possible to suitably detect the occurrence of the biting failure by using the vibration value and / or the current value correlated with the presence or absence of the biting failure.

  In order to solve the above-described problem, according to another aspect of the present invention, a crushing table rotating in a horizontal plane and a plurality of crushing rollers arranged on the crushing table at predetermined intervals along the rotation direction are provided. A grinding method using a vertical roller mill provided is provided. This pulverization method includes a selection step of selecting a pulverized material supplied from the outside to a vertical roller mill into a normal pulverized material having a particle size smaller than a predetermined first particle size and a massive pulverized material having a particle size larger than the first particle size. A preliminary supply step of supplying the crushed material onto the pulverization table before starting the vertical roller mill; and starting the vertical roller mill and supplying the normal pulverized material onto the rotating pulverization table, And a starting step in which a mixture of the object to be pulverized and the mass to be pulverized is usually squeezed between the pulverizing rollers. The start of the vertical roller mill means that the grinding table of the vertical roller mill is rotated to start the grinding operation of the object to be ground between the grinding table and the grinding roller.

  With such a configuration, before the vertical roller mill is started, a mass to be crushed having a particle size of 1st particle size or more is supplied in advance onto the pulverization table, and then the vertical roller mill is started and the space between the pulverization table and the pulverization roller is increased. Ordinarily, the mixture of the material to be crushed and the mass to be crushed can be bitten and the pulverization can be started. Thereby, a massive pulverized object having a high biting resistance with respect to the pulverizing table and the pulverizing roller can be suitably entrapped, the pulverizing roller can be lifted, and the pulverized object can be normally entrained. Therefore, even if the water content of the object to be pulverized is not suitable, the object to be pulverized can be squeezed between the pulverizing roller and the pulverizing table and pulverized, and the fine powder of the object to be pulverized can be stably supplied.

  The first particle size may be equal to or greater than the clearance between the grinding table and the grinding roller. As a result, a massive object to be crushed having a particle size equal to or larger than the clearance can be suitably caught between the grinding table and the grinding roller without slipping. Therefore, the pulverized roller can be lifted by this bitten mass to be pulverized, and other normal pulverized material that is slippery can be suitably bitten.

  In the sorting step, the object to be pulverized having a predetermined second particle size larger than the first particle size is removed from the object to be pulverized supplied from the outside to the vertical roller mill, so You may make it classify | collect a massive to-be-pulverized thing less than 2 particle sizes. Thereby, the upper limit of the particle size of a massive ground material can be regulated, and the massive ground material can be supplied to the vertical roller mill to an appropriate size.

  In order to solve the above-described problem, according to another aspect of the present invention, a crushing table rotating in a horizontal plane and a plurality of crushing rollers arranged on the crushing table at predetermined intervals along the rotation direction are provided. A vertical roller mill is provided that crushes an object to be crushed between a crushing table and a crushing roller. The vertical roller mill includes first storage means for storing a normal pulverized material having a particle size smaller than a predetermined first particle size selected from the pulverized material supplied to the vertical roller mill from the outside; A second storage means for storing a mass to be pulverized having a particle size equal to or larger than the first particle size; a first supply means for supplying the normal pulverized substance stored in the first storage means onto the pulverization table; and a second storage means And a second supply means for supplying the massive pulverized material stored on the pulverizing table. With this configuration, it is possible to provide a vertical roller mill that can suitably execute the pulverization method.

  Further, the detection means detects a vibration value indicating the magnitude of vibration generated in the vertical roller mill in the crushing process, and when the detected vibration value is equal to or greater than a predetermined reference vibration value, or In the pulverization process, when a load value representing the load of the driving device that rotates the pulverization table is detected, and the detected load value is equal to or less than a predetermined reference load value that is set in advance, there is a problem that the object to be crushed is not properly caught. You may make it determine with having generate | occur | produced. Thereby, it is possible to suitably detect the occurrence of the biting failure by using the vibration value and / or the current value correlated with the presence or absence of the biting failure.

  The first particle size may be equal to or greater than the clearance between the grinding table and the grinding roller. As a result, a massive object to be crushed having a particle size equal to or larger than the clearance can be suitably caught between the grinding table and the grinding roller without slipping. Therefore, the pulverized roller can be lifted by this bitten mass to be pulverized, and other normal pulverized material that is slippery can be suitably bitten.

  As described above, according to the present invention, even if the moisture content of the object to be pulverized is not suitable, the object to be pulverized can be stably caught between the pulverizing roller and the pulverizing table.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  A vertical roller mill according to an embodiment of the present invention will be described below. In the following embodiment, an example in which a vertical roller mill is applied to a pulverized coal machine of a thermal power generation facility and petroleum coke is used as a material to be pulverized will be described. It is not limited to examples.

  First, with reference to FIG. 1, the outline | summary of the thermal power generation equipment (thermal power generation plant) concerning this embodiment is demonstrated. FIG. 1 is a schematic diagram showing an outline of the thermal power generation facility according to the present embodiment.

  As shown in FIG. 1, in a thermal power generation facility, petroleum coke, which is a fuel for power generation (hereinafter sometimes simply referred to as “fuel”), is lifted and stored in a raw material yard 1. As for the raw material of the petroleum coke, those having a particle size of less than 10 mm occupy 90% or more, and those having a particle size of 10 mm or more are about 10%. In the raw material yard 1, the raw material of petroleum coke is selected according to the particle diameter using a sieve. For example, mainly for the purpose of removing foreign substances, petroleum coke having a predetermined second particle diameter (for example, 100 mm) or more, foreign substances, etc. are removed from the petroleum coke raw material by using a relatively coarse sieve (primary sorting). .

  Petroleum coke having a particle size of less than the second particle size thus selected is transported to a power plant by a transport trailer, put into a raw material receiving hopper 2, and disposed on an upper portion of a vertical roller mill 5 which is a pulverized coal machine. It is stored in the hopper 3 (bunker). In the present embodiment, for example, before putting into the raw material receiving hopper 2, the petroleum coke after the primary sorting is made to have a predetermined first particle size (for example, 10 mm) or more using a relatively fine sieve. Sorting into large petroleum coke (bulk fuel) and small petroleum coke (normal fuel) less than the first particle size (for example, 10 mm) (secondary sorting), this bulk fuel and normal fuel are put into different hoppers 3 respectively. The point of storage is characteristic, but the details will be described later.

  Next, the petroleum coke stored in the hopper 3 is supplied into the vertical roller mill 5 from time to time by the coal feeder 4 and is pulverized and pulverized by the vertical roller mill 5. Petroleum coke fine powder (for example, a particle size of 125 μm) pulverized by the vertical roller mill 5 is blown into the boiler 6 together with air and burned in the boiler 6. The boiler 6 receives water supply from the condensate pump 7 and the water supply pump 8, and generates water vapor by boiling the supplied water by heat generated when the fine powder of the petroleum coke is burned by a burner. . The exhaust gas from the boiler 6 at the time of combustion is purified by a soot treatment facility 12 including a denitration facility 9, an electrostatic precipitator 10, a desulfurization facility 11, and the like, and discharged to the atmosphere.

  On the other hand, the steam generated by the boiler 6 is transferred from the boiler 6 to the turbine generator 13, and the turbine generator 13 rotates the turbine with the steam to generate electric power. During this power generation, the turbine generator 13 is cooled by the cooling water supplied from the cooling tower 14 via the circulating water pump 15. The electric power generated by the turbine generator 13 is transmitted to the outside from the transmission tower 18 via the main transformer 16 and the circuit breaker 17.

  As described above, in the thermal power generation facility according to the present embodiment, the vertical roller mill 5 has a function of pulverizing, for example, petroleum coke as fuel for the boiler 6 as an object to be crushed and supplying it to the boiler 6. The saddle type roller mill 5 will be described in detail below.

  Next, the vertical roller mill 5 according to the present embodiment will be described with reference to FIG. FIG. 2 is a partially cutaway front view showing the configuration of the vertical roller mill 5 according to the present embodiment.

  As shown in FIG. 2, the vertical roller mill 5 includes a crushing table 22 that rotates in a horizontal plane below a crushing space surrounded by a substantially cylindrical housing 21 including an upper housing 21a, an intermediate housing 21b, and a lower housing 21c. A plurality of (three in the figure) crushing rollers 23 arranged on the crushing table 22 at predetermined intervals along the rotation direction are arranged.

  The crushing table 22 has a substantially circular dish shape whose outer peripheral edge protrudes upward, and a table liner 22 a for wear prevention is disposed on the upper surface of the crushing table 22. Further, in the center of the crushing table 22, a substantially tapered receiving portion 22b protruding upward is provided.

  Below the vertical roller mill 5, a motor 24 and a speed reducer 25, which are driving devices for rotating the crushing table 22, are disposed. By transmitting the driving force generated by the motor 24 to the crushing table 22 via the speed reducer 25, the crushing table 22 has a predetermined low speed around a rotating shaft (not shown) extending in the vertical direction. It rotates horizontally (for example, 50 rpm).

  Each crushing roller 23 is rotatably and swingably supported by a roller support device 26 including a roller journal. The crushing roller 23 can swing up and down around the support shaft of the roller support device 26. The roller support device 26 is connected to a pressurizing device 27 configured by, for example, a hydraulic loader. The pressure device 27 applies a load that presses the grinding roller 23 downward toward the grinding table 22 via the roller support device 26. With this configuration, the crushing roller 23 rotates in accordance with the rotation of the crushing table 22 that rotates horizontally as described above while being pressed against the crushing table 22 with a predetermined load with the object to be crushed. Even when the crushing roller 23 is pressed to the lowest position, a gap (clearance) having a predetermined dimension (for example, 3 to 5 mm) is generated between the crushing table 22 and the crushing roller 23. Thereby, since the crushing roller 23 and the crushing table 22 are not in direct contact with each other, damage to both can be prevented. During the pulverization operation, if an object to be crushed larger than the clearance is caught, the pulverization roller 23 rotates about the support shaft of the roller support device 26 and lifts upward away from the pulverization table 22. Yes.

  In the housing 21, a fixed classifier 28 is disposed above the crushing roller 23, and the lower end of a substantially cylindrical coal supply pipe 29 is provided inside the fixed classifier 28. It is arranged. The upper end of the coal supply pipe 29 is connected to the coal feeder 4 (see FIG. 1), and normal fuel (petroleum coke) as a material to be crushed is supplied from the coal feeder 4 into the vertical roller mill 5. Functions as a fuel supply pipe.

  Further, a rotary separator 30 and a rotary separator blade 31 are disposed so as to surround the coal supply pipe 29, and the rotary separator 30 is driven by a rotary separator driving motor 32. In addition, an outlet port 33 is provided at the upper portion of the upper housing 21a for supplying fine powder obtained by pulverizing the object to be pulverized to the boiler 6 (see FIG. 1).

  In addition to the coal supply pipe 29, the vertical roller mill 5 according to the present embodiment is provided with a charging chute 35 for supplying a bulk fuel having a particle size larger than that of the normal fuel onto the grinding table 22. Has been. The charging chute 35 is disposed so as to penetrate the housing 21 and have a lower end positioned above the crushing table 22. Details of the charging chute 35 will be described later.

  Next, the pulverizing operation of the vertical roller mill 5 configured as described above will be described. During the pulverization operation, the material to be crushed (petroleum coke) is supplied from the coal feeder 4 through the coal supply pipe 29 into the housing 21 of the vertical roller mill 5. The material to be crushed falls on the receiving portion 22b in the center of the pulverizing table 22, and then moves on the pulverizing table 22 toward the outer peripheral portion by the centrifugal force generated by the rotation of the pulverizing table 22, and is pulverized with the pulverizing roller 23. It is bitten between the table 22 and pulverized and pulverized. At this time, when an object to be crushed is caught between the pulverizing roller 23 and the pulverizing table 22, the pulverizing roller 23 is, for example, 10 upwards from the pulverizing table 22 even when pressed by a pressure device 27 with a predetermined load. It is lifted until it is separated by about -15 mm, and is rotated following the rotation of the grinding table 22.

  Further, during the pulverizing operation, hot air is sent into the lower housing 21c from the air supply port 34, and this hot air is blown up from an air throat between the outer peripheral portion of the pulverizing table 22 and the inner peripheral portion of the housing 21c. . The fine powder of the material to be pulverized as described above on the pulverization table 22 is dried while rising in the housing 21 by the flow of the hot air. The fine powder conveyed to the upper part of the housing 21 falls by gravity in order from the coarser (primary classification), while the fine powder further raised is further classified by the fixed classifier 28 and the rotary separator blade 31 ( The fine powder having a predetermined particle size or less is transported to the boiler 6 from the outlet port 33. In addition, the granular material having a predetermined particle size or more that has been screened off by the secondary classification by the fixed classifier 28 or the like falls on the crushing table 22 and is newly supplied into the housing 21 from the coal supply pipe 29. It is pulverized again with the material to be crushed. In this way, pulverization and classification are repeated.

  The schematic configuration and operation of the vertical roller mill 5 according to the present embodiment have been described above. In the vertical roller mill 5, as described above, an object to be crushed (for example, petroleum coke) does not bite well into the pulverized portion between the pulverizing table 22 and the pulverizing roller 23, and a biting failure may occur. In particular, when the moisture content of the object to be pulverized is not within a numerical range suitable for pulverization (for example, 4 to 11% by mass), that is, when the moisture content is small, for example, less than 4% by mass (the object to be pulverized is excessively large). It has been found that when the moisture content is greater than 11% by mass (when the object to be crushed is excessively wet), poor biting frequently occurs. This is because the object to be crushed whose moisture content is not in the appropriate numerical range has a low frictional resistance for biting between the pulverizing table 22 and the pulverizing roller 23 and therefore slips and cannot be bitten properly. . When such a biting failure occurs and the object to be crushed is not crushed, a large vibration is generated in the pulverized portion of the vertical roller mill 5, and the operation of the vertical roller mill 5 must be stopped. As a result, the operation of the boiler 6 is stopped and the power generation of the thermal power generation facility is stopped.

  The reason why the water content of the material to be crushed is high as described above is that, for example, the petroleum coke as the material to be crushed gets wet in the raw material yard 1 or the oil coke conveyed to the raw material yard 1 The water content is originally high. The reason why the moisture content of the material to be crushed is low is, for example, that petroleum coke as the material to be crushed is stored in the raw material yard 1 for a long time and dried, or the oil coke conveyed to the raw material yard 1 The moisture content is originally low.

  Therefore, in order to cope with the above-described incomplete biting of the object to be pulverized with an inappropriate moisture content, the vertical roller mill 5 according to the present embodiment is a normal object to be pulverized having a particle diameter less than a predetermined first particle size (less than 10 mm). In addition, a mass to be crushed having a particle size greater than or equal to the first particle size and less than a predetermined second particle size (10 to 100 mm) can be independently supplied onto the crushing table 22.

  Here, with reference to FIG. 3, the supply mechanism of the crushed material of the vertical roller mill 5 according to the present embodiment will be described. FIG. 3 is a sectional view showing the overall structure of the vertical roller mill 5 according to the present embodiment.

  As shown in FIG. 3, the vertical roller mill 5 includes a first hopper 3a (first storage means) for normally storing the material N to be crushed and a second hopper 3b (second storage means) for storing the mass pulverized material M. ), A first coal feeder 4a (first supply means) for supplying the normal pulverized material N stored in the first hopper 3a onto the pulverization table 22 through the coal supply pipe 29, and a second hopper 3b. And a second coal feeder 4b (second supply means) for supplying the mass to be crushed M stored on the crushing table 22 through the charging chute 35.

  As described in FIG. 1, the material to be crushed (petroleum coke raw material) supplied to the raw material yard 1 is passed through a sieve corresponding to the first particle size (for example, 10 mm) before being input to the raw material receiving hopper 2. Using a sieve corresponding to the second particle size (for example, 100 mm), a normal pulverized product N having a particle size of less than the first particle size (for example, particle size of less than 10 mm), and a lump shape having a particle size greater than or equal to the first particle size and less than the second particle size. The material to be pulverized M is selected (for example, particle size 10 to 100 mm).

  As shown in FIG. 3, the sorted normal object N is stored in the first hopper 3a, and the massive object M is stored in the second hopper 3b. A first coal feeder 4a is connected to the lower portion of the first hopper 3a that normally stores the object N to be crushed, and a cylindrical tube extending vertically on the grinding table 22 is connected to the lower portion of the first coal feeder 4a. The constituted coal supply pipe 29 is connected. On the other hand, a second coal feeder 4b is connected to the lower portion of the second hopper 3b for storing the mass to be crushed M. The lower portion of the second coal feeder 4b extends in the vertical direction and then skews. An input chute 35 is connected to the upper part of the crushing table 22. The capacities / arrangements of the first hopper 3a and the second hopper 3b can be set to any capacities / arrangements according to the operation mode of the thermal power generation facilities, but the receiving equipment (raw material receiving hopper 2, Considering the relationship with the receiving conveyor). It is desirable to set a suitable capacity and arrangement. For example, when it is necessary to increase the capacity of the first hopper 3a in a business power plant or the like, the capacity of the second hopper 3b may be decreased accordingly.

  With this configuration, by operating the first coal feeder 4a, the normal pulverized object N can be introduced into the housing 21 from the first hopper 3a and supplied onto the pulverizing table 22. Further, by operating the second coal feeder 4b, the massive object M can be put into the housing 21 from the second hopper 3b and supplied onto the grinding table 22. As described above, the vertical roller mill 5 according to the present embodiment has two independent and independent systems for supplying the object to be crushed.

  With such a mechanism, during normal operation of the vertical roller mill 5, the normal object N stored in the first hopper 3a can be put on the crushing table 22 to perform a normal crushing operation. When the vertical roller mill 5 is started up (during the crushing operation), when the occurrence of a biting failure of the object to be crushed is detected, or when the vertical roller mill 5 is started up (at the start of operation), the second hopper 3b A predetermined amount (for example, 30 to 50 kg) of the stored mass to be pulverized M can be additionally charged onto the pulverization table 22.

  In this way, in addition to the normal pulverized material N, the massive pulverized material M is additionally supplied, so that the large crushed material M (particle size 10 to 100 mm) and the normal pulverized material are placed on the pulverization table 22. The product N (particle size less than 10 mm) is present in a mixed state. In this mixture, compared with a conventional general object to be pulverized (a thing having a particle diameter of less than 10 mm accounts for 90%), a large proportion (for example, 50%) of a large lumped object M having a first particle diameter of 10 mm or more. %). As described above, when a large amount of large block fuel is mixed, the fuel biting resistance (friction resistance against the crushing table 22 and the crushing roller 23) increases, so that the fuel flows between the crushing roller 23 and the crushing table 22. It becomes easy to bite.

  Therefore, even when the moisture content of the material to be crushed is not in an appropriate numerical range (for example, when the moisture content is less than 4% by mass or greater than 11% by mass), it is stored in the second hopper 3b. By putting the massive object M to be crushed onto the crushing table 22, the biting can be stabilized.

  That is, as described above, when the moisture of the normal grinding object N is large or small, the friction coefficient of the normal grinding object N against the grinding table 22 and the grinding roller 23 is small, so that the normal grinding object N is preferably used. Easy to slip without biting. However, by additionally supplying the mass to be pulverized M in addition to the normal material to be pulverized N, the friction coefficient of the mixture of the mass to be pulverized M and the normal material to be pulverized N becomes large. The crushing table 22 and the crushing roller 23 are suitably bitten, and the crushing roller 23 is lifted. As a result, the normal pulverized object N that has slipped can be easily bitten. Therefore, during the crushing operation of the vertical roller mill 5, slipping of the object to be crushed and vibration of the vertical roller mill 5 can be prevented, and the crushing operation can be stabilized.

  The first particle size, which is the lower limit of the particle size of the mass to be crushed M, is preferably set to a clearance (for example, 3 to 5 mm) or more between the pulverizing table 22 and the pulverizing roller 23. Thereby, during the pulverization operation, the mass to be pulverized M is caught in the gap between the pulverization table 22 and the pulverization roller 23, and by lifting the pulverization roller 23, it is possible to secure a space for another object to be entrapped. The effect of improving the biting failure increases.

  In addition, the normal pulverized object N and the massive pulverized object M are those having a small particle diameter within the above particle size range (usually, the pulverized object N is less than 10 mm, for example, the massive pulverized object M is 10 to 100 mm). It is preferable that various sizes up to a large size are mixed and the particle size is varied as much as possible. As a result, the mixture of the object to be pulverized N and the object to be pulverized in a mass is easily caught between the pulverizing table 22 and the pulverizing roller 23.

  With the mechanism as described above, it is possible to stabilize the biting of the object to be pulverized by additionally supplying the mass object M to be pulverized in addition to the object N to be pulverized. Therefore, in the present embodiment, when the vertical roller mill 5 is difficult to bite the object to be crushed or when a biting failure is detected during the pulverization operation of the vertical roller mill 5, the above-mentioned massive object M is removed. We are going to supply.

  Here, with reference to FIG. 4, a configuration for detecting a biting failure and supplying the mass to be crushed M in the vertical roller mill 5 according to the present embodiment will be described. FIG. 4 is a schematic view schematically showing the configuration of the main part of the vertical roller mill 5 according to the present embodiment.

  As shown in FIG. 4, the roller support device 26 is rotatable about a support shaft 261 as a fulcrum. Thereby, the roller support device 26 supports the crushing roller 23 so as to be swingable in the vertical direction around the support shaft 261. Further, the upper projecting portion 262 of the roller support device 26 is rotatably connected to the piston rod 272 of the first hydraulic cylinder 271 that constitutes the pressurizing device 27. The first hydraulic cylinder 271 applies a predetermined pressing load to the roller support device 26 and rotates it downward, so that the pulverizing roller 23 can be pressed toward the pulverizing table 22 with the pressing load.

  In the vertical roller mill 5, the pulverizing roller 23 is pressed against the pulverizing table 22 in this way, and the object to be pulverized is pulverized between the pulverizing roller 23 and the pulverizing table 22. At this time, as described above, when the moisture content of the material to be pulverized is not within the appropriate numerical range (for example, when the moisture content is less than 4% by mass or greater than 11% by mass), the bite is poor. Occurs.

  In order to cope with such a biting failure, the vertical roller mill 5 according to the present embodiment includes a detection means 70 for detecting such a biting failure and a detection result of the detection means 70 as shown in FIG. And a control unit 60 for controlling the supply mechanism of the pulverized product.

  The controller 60 controls the first coal feeder 4a and the second coal feeder 4b to control the supply of the normal pulverized material N and the massive pulverized material M to the pulverization table 22. For example, during normal crushing operation of the vertical roller mill 5 (when no biting failure occurs), the control unit 60 operates the first coal feeder 4a and does not operate the second coal feeder 4b. As a result, control is performed so that only the normal object N stored in the first hopper 3 a is continuously supplied onto the crushing table 22 through the coal supply pipe 29.

  In addition, when the vertical roller mill 5 is started, the control unit 60 first operates the second coal feeder 4b and puts the mass to be crushed M stored in the second hopper 3b on the pulverization table 22 in a predetermined amount. It controls to supply only (for example, 30-50 kg). Next, when the vertical roller mill 5 is activated and the pulverization operation is started, the control unit 60 controls the normal pulverized object N stored in the first hopper 3a to be continuously supplied onto the pulverization table 22. To do.

  The detecting means 70 detects the occurrence of a biting failure of the object to be crushed between the pulverizing table 22 and the pulverizing roller 23 during the pulverizing operation by the vertical roller mill 5. In order to detect such a biting failure, for example, a method of detecting vibration generated in the vertical roller mill 5 during a pulverizing operation, a method of detecting a load of a motor 24 that is a driving device for rotating the pulverizing table 22, and There is.

  First, a method for detecting vibration generated in the vertical roller mill 5 will be described. When the object to be crushed is properly biting during the crushing operation by the vertical roller mill 5, fine vibration is stably generated in the vertical roller mill 5, and the vibration value of the vertical roller mill 5 (for example, the amplitude of vibration) ) Is small. On the other hand, when the object to be crushed slips and a biting failure occurs, large vibration is generated in the vertical roller mill 5 as described above, and the vibration value increases. Therefore, by detecting the vibration value of the vibration generated in the vertical roller mill 5, it is possible to detect whether or not a biting failure has occurred.

  Next, a method for detecting the load of the motor 24 will be described. When the object to be crushed is properly biting during the crushing operation by the vertical roller mill 5, a relatively large load is applied to the motor 24 that rotates the crushing table 22 at a predetermined speed. (For example, the current value of electric power (constant voltage) consumed by the motor 24) increases. On the other hand, when the object to be crushed slips and a biting failure occurs, the pulverization table 22 becomes nearly idle, so that a relatively small load is applied to the motor 24. As a result, the load of the motor 24 is reduced. The value (for example, the current value) becomes small. Therefore, by detecting the current value of the power consumed by the motor 24 as the load of the motor 24 that rotates the crushing table 22, for example, it is possible to detect the occurrence of a biting failure.

  From this point of view, as shown in FIG. 4, the detection means 70 according to the present embodiment includes, for example, a vibration meter 71 that detects a vibration value generated in the saddle roller mill 5 and a motor 24 that rotates the grinding table 22. An ammeter 72 that detects a current of consumed power and a determination unit 73 that determines whether or not the biting failure has occurred based on the detected vibration value and / or current value.

  The vibrometer 71 is mounted, for example, on the housing 21 (for example, the outer surface of the lower housing 21c) of the vertical roller mill 5, and continuously detects the vibration value (the amplitude of the vibration) in the housing 21 during the crushing operation. To do. Note that the vibrometer 71 can be installed at any location of the vertical roller mill 5. The ammeter 72 is an example of a detector that detects the load value of the motor 24 that rotates the crushing table 22, and continuously detects the current value of the motor during the crushing operation. The vibration value and current value detected by the vibrometer 71 and ammeter 72 are input to the determination unit 73.

  The determination unit 73 is configured by an arithmetic processing circuit or the like, and when the vibration value detected by the vibration meter 71 is a predetermined reference vibration value (for example, the vibration amplitude is 150 μm) or more, or When the current value detected by the ammeter 72 is equal to or less than a predetermined reference current value (for example, 18A) set in advance, it is determined that a biting failure of the object to be crushed has occurred. The reference vibration value and reference current value are determined according to the vibration value and current value detected during normal operation of the vertical roller mill 5, and the vibration value and current value detected during abnormal operation (when biting is defective). , Are set in advance.

  Thus, in the present embodiment, the determination unit 73 determines that a biting failure has occurred when either the detected vibration value or current value indicates an abnormal value. Thereby, the detection sensitivity of the occurrence of the biting failure can be increased. However, the present invention is not limited to this example, and when the detected vibration value is equal to or less than the reference vibration value and the detected current value is equal to or less than the reference current value, that is, both the detected vibration value and current value are detected. If the value indicates an abnormal value, the determination unit 73 may determine that a biting failure has occurred.

  In this way, when it is determined that a biting failure has occurred, the determination unit 73 of the detection means 70 outputs a biting failure occurrence signal to the control unit 60. Then, the control unit 60 operates the second coal feeder 4b in response to the biting failure occurrence signal, and a predetermined amount of the mass to be crushed M stored in the second hopper 3b is placed on the pulverizing table 22. It controls to supply only (for example, 30-50 kg). At this time, the control unit 60 continues the operation of the first coal feeder 4a and controls the normal pulverized material N stored in the first hopper 3a to be continuously supplied onto the pulverizing table 22.

  Next, with reference to FIG. 5, the grinding | pulverization method of the to-be-ground material using the vertical roller mill 5 of the above structures is demonstrated. In addition, FIG. 5 is a flowchart which shows the grinding | pulverization method of the to-be-ground material using the vertical roller mill 5 concerning this embodiment.

  As shown in FIG. 5, first, in step S10, in the raw material yard 1, from a material to be crushed (petroleum coke) supplied to the vertical roller mill 5 using a sieve having a second particle size (for example, 100 mm), An object to be crushed having a particle size of 2 or more is selected and removed (step S10: primary selection step). Thereby, the excessively large petroleum coke of 100 mm or more and foreign matters mixed in the petroleum coke can be removed.

  Next, in Step 12, in the raw material yard 1, the first screened material to be pulverized having a particle size of less than the second particle size is passed through a sieve having a particle size of the first particle size (for example, 10 mm). Sorting into the pulverized product N and the massive pulverized product M having the first particle size or more (step S12: secondary sorting step). Note that it is also possible to change the order of step S10 and step S12 and sort by the second particle size (100 mm) after sorting by the first particle size (10 mm).

  As a result of such primary and secondary sorting, a mass to be pulverized M having a particle size of not less than the first particle size and less than the second particle size (for example, 10 to 100 mm) and a normal material to be pulverized N having a particle size of less than the first particle size are obtained. can get. The proportion of the mass to be crushed M in the entire pulverized material is, for example, 10%, which is relatively small, and the pulverized material N is usually 90%, which is relatively large. The normal pulverized object N and the massive pulverized object M thus selected are respectively loaded into the first hopper 3a and the second hopper 3b of the vertical roller mill 5 and stored.

  Further, in step S14, before the vertical roller mill 5 is started, the massive object M is supplied onto the pulverizing table 22 of the vertical roller mill 5 (step S14: preliminary supply step). Specifically, the control unit 60 operates the second coal feeder 4b to pulverize the mass to be crushed M having a particle diameter of 10 to 100 mm stored in the second hopper 3b through the charging chute 35. Put it on the table 22. The supply amount of the mass to be crushed M can be, for example, 30 to 50 kg. Since the vertical roller mill 5 is not activated at the time of preliminary supply of such a mass to be pulverized M, the pulverizing table 22 and the first coal feeder 4a are also stopped, and the pulverizing operation is not performed.

  Thereafter, in step S16, the vertical roller mill 5 is activated (step S16: activation process). Specifically, when the vertical roller mill 5 is started, the crushing table 22 starts to rotate, and the first coal feeder 4a is operated so that the normal pulverized object N stored in the first hopper 3a is removed. , Continuously supplied onto the crushing table 22. As a result, the mass to be pulverized M previously supplied onto the pulverization table 22 as described above and the normal pulverization object N are mixed, and this mixture moves to the outer peripheral side of the pulverization table 22 by centrifugal force. It is suitably bitten between the crushing table 22 and the crushing roller 23.

  Conventionally, when the vertical roller mill 5 is started, the moisture content of the object to be crushed is not in an appropriate range (less than 4 mass%, 11 mass% or more), and of course, the moisture content is in an appropriate range (4 to 11 mass%). ), The object to be crushed is slippery and difficult to bite between the crushing table 22 and the crushing roller 23, so that the crushing operation is often not stable.

  On the other hand, in the present embodiment, as described above, before the vertical roller mill 5 is started, the mass to be crushed M having a high biting resistance is input in advance, and then the vertical roller mill 5 is started. Even if the moisture content of the object to be crushed is in an inappropriate range, the mixture of the object to be pulverized N and the mass to be pulverized M can be suitably bitten without slipping. Therefore, when the vertical roller mill 5 is started, the object to be crushed can be suitably bitten and the pulverization operation can be started stably.

  Further, in step S18, the normal pulverization operation is continued while supplying only the normal object N (step S18: pulverization step). Specifically, while the grinding table 22 is rotated, the normal grinding object N stored in the first hopper 3a is continuously supplied onto the grinding table 22 at a predetermined supply amount. As a result, the object to be pulverized N is usually crushed between the pulverizing table 22 and the pulverizing roller 23 and pulverized.

  During the crushing operation (crushing process) by the vertical roller mill 5, the detection means 70 monitors the occurrence of a biting failure. When the biting failure does not occur normally, all the crushing rollers 23 are pressed against the crushing table 22 by the pressure device 27, and the normal object N to be crushed is between the crushing table 22 and the crushing roller 23. It is bitten normally and crushed. At this normal time, the current value detected by the ammeter 72 is stable at a normal current value (for example, 21 to 24A), and the vibration value (vibration amplitude) detected by the vibration meter 71 is normal. Stable vibration value (for example, 21 to 25 μm).

  Next, in step S20, the detection means 70 of the vertical roller mill 5 detects the occurrence of a biting failure of the object to be crushed (step S20: pulverization step). In the pulverization process in step S18, if a biting failure (slip of the object to be crushed, vibration of the vertical roller mill 5) occurs, the current value detected by the ammeter 72 is the reference current value (for example, 18A). The vibration value detected by the vibrometer 71 rises to the reference vibration value (for example, 150 μm) or more. Then, the detection means 70 detects the occurrence of biting failure based on these vibration values and current values.

  Then, in step S22, the bulk pulverized material M is additionally supplied by a predetermined amount onto the pulverization table 22 of the vertical roller mill 5 (step S22: Bulk pulverized material supply step). Specifically, the control unit 60 operates the second coal feeder 4b to pulverize the mass to be crushed M having a particle diameter of 10 to 100 mm stored in the second hopper 3b through the charging chute 35. It is put on the table 22 and is normally supplied to the object N to be crushed. The supply amount of the mass to be crushed M can be 30 to 50 kg, for example, and the supply period can be 10 seconds, for example. At the time of additional supply of such a mass to be pulverized M, the pulverization table 22 and the first coal feeder 4a are also in operation, and the normal pulverized object N is continuously supplied in parallel. The supply amount per unit time of the normal pulverized object N and the massive pulverized object M can be set to the same level.

  In this way, by adding the mass to be crushed M having a high biting resistance, the mixture of the material to be crushed N and the mass to be crushed M is normally slid between the crushing table 22 and the crushing roller 23. It will come to bite suitably. Accordingly, it is possible to eliminate the biting defects that are normally caused by supplying only the object N to be crushed and to perform stable pulverization.

  If the biting failure is not solved by the one-time injection of the mass to be crushed M (when the slip and vibration are not cured), the biting failure is detected until the biting failure is eliminated. 30 to 50 kg of the mass to be crushed M is fed to each. As a result, the existence ratio of the mass to be crushed M having a high biting resistance can be increased, and the biting failure can be eliminated. The supply amount of the mass to be crushed M can be increased according to the state of occurrence of slip or vibration.

  As described above, when a biting failure occurs, in addition to the normal pulverized object N, the bulk pulverized object M is additionally supplied as appropriate, so that the moisture content of the pulverized object is not within an appropriate range and is slippery. Even if it is a case (when moisture content is less than 4% by mass, for example, or when it is 11% by mass or more and a lot of moisture, etc.), it is caught between the crushing table 22 and the crushing roller 23. It is possible to stabilize the pulverization operation by suitably biting the mixture of the massive pulverized material M and the normal pulverized material N having high resistance. Therefore, it is possible to improve the biting failure generated in the middle of the pulverization process and reduce the vibration of the vertical roller mill 5 and to secure a sufficient amount of pulverized material by the vertical roller mill 5 so that the boiler 6 has a sufficient amount. Fine powder can be continuously supplied.

  Next, a description will be given of the results of experiments 1 to 3 in which the object to be pulverized is pulverized using the vertical roller mill 5 according to the present embodiment. In any of Experiments 1 to 3, the vertical roller mill 5 is a pulverized coal pulverizer for petroleum coke (model: Mitsubishi vertical mill, capacity: 12.8 t / h, fineness: 200 mesh (nominal size 75 μm) 95%, classification method) : Fixed / rotary classifier).

(Experiment 1)
Before the vertical roller mill 5 is started, lump fuel (bulk petroleum coke) having a particle diameter of 10 to 100 mm is supplied onto the crushing table 22 by a half (30 kg) of the amount held in the vertical roller mill 5, and then The vertical roller mill 5 was started, and the pulverizing table 22 was rotated while supplying normal fuel (normal petroleum coke) having a particle size of 10 mm or less to start the pulverizing operation. As a result, it was confirmed that even if the water content of petroleum coke was 3% by mass or 12% by mass, the petroleum coke was reliably caught and the vertical roller mill 5 could be started stably.

(Experiment 2)
When the load is changed during the operation of the vertical roller mill 5 and a fuel slip occurs, the bulk fuel having a particle diameter of 10 to 100 mm (the bulk petroleum coke) is ½ of the retained amount in the vertical roller mill 5 (30 kg). ) Only on the crushing table 22. As a result, it was confirmed that the bite roller mill 5 could be prevented from being bitten and slipped regardless of whether the water content of petroleum coke was 3% by mass or 13% by mass.

(Experiment 3)
When a normal fuel with a moisture content of 3-4 mass% and a normal fuel of 12-14 mass% are continuously supplied, the slip / vibration is detected when the fuel slip phenomenon and the vibration of the vertical roller mill 5 are not resolved. At that time, 30 kg of bulk fuel having a particle size of 10 to 100 mm was continuously charged. As a result, it was confirmed that the above-mentioned slip phenomenon / vibration was eliminated and the vertical roller mill 5 could continue the pulverization operation stably.

  According to the above experimental results, even when the vertical coke roller 5 is started up or when the load changes, even if the oil coke, which is the material to be crushed, fails to bite, Thus, it can be seen that the oil coke can be suitably bitten. The particle size distribution of the normal fuel is 90% or more when less than 10 mm, and there are few bulk fuels of 10 mm or more with high biting resistance. It is considered effective in suppressing slip and vibration.

  The vertical roller mill 5 and the pulverizing method according to this embodiment have been described in detail above. According to this embodiment, when the vertical roller mill 5 is started, when the load is low, or when the load is changed, the object to be pulverized (slip of the object to be pulverized, vibration of the vertical roller mill 5) occurs. In addition, by supplying the mass to be crushed M, the mixture of the mass to be crushed M and the normal pulverized material N can be forcibly bitten between the grinding roller 23 and the grinding table 22. For this reason, the crushing operation can be continuously performed stably without stopping the vertical roller mill 5.

  In particular, in this embodiment, during normal operation of the vertical roller mill 5 (when no biting failure occurs), only the material to be pulverized N is normally supplied, and when there is an abnormality (when biting failure occurs). , It is characterized by additionally supplying a mass to be crushed M. As a result, a mass to be crushed M having a high biting resistance is sandwiched between the crushing roller 23 and the crushing table 22, and the crushing failure is usually caused by the slip of the material to be crushed N by lifting the crushing roller 23. Vibration can be eliminated. Therefore, the combustion of the pulverized coal in the boiler 6 can be stabilized and the boiler 6 can be prevented from stopping, so that the power generation in the thermal power generation facility can be stably continued.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above embodiment, the vertical roller mill is applied to a pulverized coal machine of a thermal power generation facility, and an example of pulverizing petroleum coke as fuel for the boiler 6 as an object to be crushed has been described. It is not limited to examples. A vertical roller mill is a material to be crushed, for example, coal as a fuel for thermal power generation, PCI (pulverized coal injection) coal used as supplementary fuel in a blast furnace of an ironmaking plant, raw materials such as cement raw materials, chemical products, etc. It is also applicable when pulverizing the like.

  In the above-described embodiment, the detection means 70 detects the occurrence of a biting failure based on the vibration value of the vertical roller mill 5 and the load value (for example, current value) of the motor 24 that rotates the crushing table 22. The present invention is not limited to such an example. For example, the occurrence of a biting failure can be detected based on the natural lift amount of each crushing roller 23 that accompanies the biting of the object to be crushed during the crushing motion.

  That is, during normal crushing operation, an object to be crushed is caught between the crushing roller 23 and the crushing table 22, so that the crushing roller 23 is separated from the crushing roller 23 with the support shaft 261 of the roller support device 26 as a fulcrum. Rotate in the direction and lift naturally by the lift amount corresponding to the biting thickness of the object to be crushed. For this reason, when the natural lift amount is within an appropriate range, it is possible to determine that the crushing roller 23 has no biting failure and is normal, while the natural lift amount is However, if it is smaller than the predetermined reference lift amount, it can be determined that the crushing failure has occurred in the crushing roller 23.

  Moreover, in the said embodiment, although the particle size of the massive to-be-ground material M was 10-100 mm, this invention is not limited to this example. The particle size range of the mass to be crushed M depends on the type, size, and quality of the crushed material to be supplied, the specifications of the vertical roller mill 5, the set value of the clearance between the crushing table 22 and the crushing roller 23, and the like. Accordingly, it can be set to an arbitrary particle size.

  The present invention is applicable to a vertical roller mill for pulverizing an object to be crushed and a pulverization method using the same.

It is the schematic which shows the outline | summary of the thermal power generation equipment concerning the 1st Embodiment of this invention. It is a partially notched front view which shows the structure of the vertical roller mill concerning the embodiment. It is sectional drawing which shows the whole structure of the vertical roller mill concerning the embodiment. It is the schematic which shows schematically the structure of the principal part of the vertical roller mill concerning the embodiment. It is a flowchart which shows the grinding | pulverization method of the to-be-ground material using the vertical roller mill concerning the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material yard 2 Raw material receiving hopper 3 Hopper 3a 1st hopper 3b 2nd hopper 4 Charging machine 4a 1st feeding machine 4b 2nd feeding machine 5 Vertical roller mill 6 Boiler 13 Turbine generator 21 Housing 22 Grinding table 23 Grinding Roller 24 Motor 25 Reducer 26 Roller support device 27 Pressurization device 28 Fixed classifier 29 Charging pipe 30 Rotary separator 31 Rotary separator blade 32 Rotary separator drive motor 33 Exit port 35 Input chute 60 Control unit 70 Detection means 71 Vibration Total 72 Ammeter 73 Determination unit 261 Support shaft 271 First hydraulic cylinder 272 Piston rod N Normal object to be pulverized M Bulk object to be pulverized

Claims (9)

A grinding method using a vertical roller mill comprising a grinding table rotating in a horizontal plane and a plurality of grinding rollers arranged at predetermined intervals along the rotational direction on the grinding table:
A sorting step of sorting the object to be crushed supplied to the vertical roller mill from the outside into a normal object to be pulverized having a particle diameter smaller than a predetermined first particle size and a mass object to be pulverized having a particle diameter larger than the first particle size;
A pulverization step of pulverizing the normal pulverized material by interposing it between the pulverizing table and the pulverizing roller while supplying the normal pulverized material onto the rotating pulverizing table;
Including
During the pulverization process, when it is detected that the normal pulverized object is caught between the pulverizing table and the pulverizing roller, the bulk pulverized object is additionally supplied onto the rotating pulverizing table. A pulverizing method using a vertical roller mill, wherein the mixture of the normal pulverized material and the massive pulverized material is pulverized between the pulverizing table and the pulverizing roller. A vibration value representing the magnitude of vibration generated in the vertical roller mill in the crushing step is detected, and the detected vibration value is greater than or equal to a predetermined reference vibration value set in advance, or
In the pulverization step, a load value representing a load of a driving device that rotates the pulverization table is detected, and when the detected load value is equal to or less than a predetermined reference load value set in advance,
The pulverization method using the vertical roller mill according to claim 1, wherein it is determined that a biting failure of the object to be crushed has occurred. A grinding method using a vertical roller mill comprising a grinding table rotating in a horizontal plane and a plurality of grinding rollers arranged at predetermined intervals along the rotational direction on the grinding table:
A sorting step of sorting the object to be crushed supplied to the vertical roller mill from the outside into a normal object to be pulverized having a particle diameter smaller than a predetermined first particle size and a mass object to be pulverized having a particle diameter larger than the first particle size;
A preliminary supplying step of supplying the massive pulverized material onto the pulverization table before starting the vertical roller mill;
While starting the vertical roller mill and supplying the normal pulverized material onto the rotating pulverizing table, the mixture of the normal pulverized material and the massive pulverized material is placed between the pulverizing table and the pulverizing roller. A starting step of biting and crushing;
A crushing method using a vertical roller mill characterized by comprising:   The pulverization method using the vertical roller mill according to any one of claims 1 to 3, wherein the first particle size is equal to or greater than a clearance between the pulverization table and the pulverization roller. In the sorting step,
The object to be crushed having a predetermined second particle size larger than the first particle size is removed from the object to be pulverized supplied from the outside to the vertical roller mill, and the second particle size is equal to or larger than the first particle size. The pulverization method using the vertical roller mill according to any one of claims 1 to 4, wherein less than the mass to be crushed is selected. A crushing table that rotates in a horizontal plane; and a plurality of crushing rollers that are arranged on the crushing table at predetermined intervals along a rotation direction, and a material to be crushed is caught between the crushing table and the crushing roller. A vertical roller mill that pulverizes:
First storage means for storing a normal pulverized material having a particle size less than a predetermined first particle size selected from the pulverized material supplied to the vertical roller mill from the outside;
A second storage means for storing a bulk pulverized product having a particle size of not less than the first particle size selected from the pulverized product;
First supply means for supplying the normal pulverized material stored in the first storage means onto the pulverization table;
Second supply means for supplying the massive pulverized material stored in the second storage means onto the pulverization table;
A vertical roller mill characterized by comprising: Detecting means for detecting occurrence of a biting failure of the object to be crushed between the pulverizing table and the pulverizing roller;
7. The bulky pulverized product is additionally supplied onto the pulverizing table by the second supply unit when occurrence of a biting failure of the pulverized product is detected by the detecting unit. The vertical roller mill described in 1. The detection means includes
A vibration value representing the magnitude of vibration generated in the vertical roller mill in the crushing step is detected, and the detected vibration value is greater than or equal to a predetermined reference vibration value set in advance, or
In the pulverization step, a load value representing a load of a driving device that rotates the pulverization table is detected, and when the detected load value is equal to or less than a predetermined reference load value set in advance,
The vertical roller mill according to claim 7, wherein it is determined that a biting failure of the object to be crushed has occurred. The vertical roller mill according to any one of claims 6 to 8, wherein the first particle size is equal to or larger than a clearance between the pulverizing table and the pulverizing roller.

Images