JP5418145B2 - Vertical mill - Google Patents

Description

  The present invention relates to a vertical mill for pulverizing coal supplied to a coal-fired boiler.

  In a coal-fired boiler using coal as fuel, massive coal is pulverized by a vertical mill into pulverized coal, and the pulverized coal is supplied together with primary air to a burner that is a combustion apparatus.

  Coal used as fuel contains incombustible substances such as ash, sulfur, and heavy metal elements, and impurities (hereinafter referred to as impurities). These impurities cause air pollution and reduce the environmental burden. Need to be removed.

  Conventionally, when coal containing impurities is used as a fuel, in order to prevent environmental pollution, a power generation facility having a coal-fired boiler is provided with a denitration device, a dust collection device, a desulfurization device, and the like as an exhaust gas treatment device.

  If the impurities of coal are removed before combustion, there is an advantage that the amount of impurities treated in the boiler exhaust gas treatment device is reduced, and coal selection for separating coal and impurities is an effective means. Moreover, since the low-grade coal can be effectively used by the coal selection, removal of impurities becomes an important issue.

  As a method for removing impurities from coal in advance before combustion, for example, by separating the coal and coal by a specific gravity separation method (floating beneficiation method) in which coal is pulverized into chunks of several centimeters and immersed in liquids having different specific gravity. Is separated (coal selection).

  Since impurities are finely dispersed in the coal, pulverization as finely as possible during coal preparation contributes to improvement of coal preparation efficiency.

  However, when coal preparation is performed by the flotation method, a large amount of water is used, so that there is a problem of drainage or securing water in a place where water cannot be obtained sufficiently.

  Further, as described above, it is preferable to pulverize as finely as possible in order to improve the coal selection efficiency, but the energy cost required for pulverization increases. Furthermore, if it grind | pulverizes finely, the installation for a process of dust will be needed and an installation cost will rise.

  Therefore, the particle size of the practical crushed powder is several centimeters, but the coal selection efficiency is limited.

JP-A-61-212340 Japanese Patent Laid-Open No. 11-226447

  In view of such circumstances, the present invention provides a vertical mill that can perform efficient coal selection by finely pulverizing coal without requiring water and without generating dust.

  The present invention includes a pulverizing table provided at the lower part of the classification chamber, a pressure roller that is pressed and rolled by the pulverizing table, and an upper part of the classification chamber through which the pulverized pulverized coal passes as an air mixed flow. A classifier disposed in such a manner, a pulverized coal feeding pipe for sending an air mixed stream of classified pulverized coal, and an impurity separation device provided in the pulverized coal feeding pipe, The apparatus includes: a first magnet provided around the pulverized coal feed pipe; a second magnet located downstream of the first magnet and provided at a part of the circumference of the pulverized coal feed pipe; A branch pipe communicating with the pulverized coal feed pipe on the downstream side of the second magnet, wherein the first magnet forms an excitation area, the second magnet forms an attraction area, and the excitation area Exciting impurities in pulverized coal passing through the gas, and guiding the excited impurities to the branch pipe by the suction region Te, it relates to a vertical mill for separating impurities.

  According to the present invention, the second magnet is provided at an upper end portion of the pulverized coal feeding pipe, and the branch pipe is related to a vertical mill that separates upward.

  According to the present invention, the second magnet is provided at a lower end portion of the pulverized coal feed pipe, and the branch pipe is related to a vertical mill that separates downward.

  In the present invention, two sets of impurity separation devices are connected to the pulverized coal feed pipe, and one impurity separation device includes the second magnet provided at an upper end portion of the pulverized coal feed pipe, and the branch. The other impurity separation device is configured such that the second magnet is provided at the lower end of the pulverized coal feed pipe, and the branch pipe is separated downward. This relates to a vertical mill.

  In addition, the present invention provides the excitation region portion and the suction region portion of the pulverized coal feed pipe having a large diameter with respect to the pulverized coal feed tube, and the mixed air flow that flows through the excitation region portion and the suction region portion. The present invention relates to a vertical mill in which the flow rate is reduced with respect to the pulverized coal feeding pipe portion.

  In the present invention, another impurity separation device is provided adjacent to the classification chamber, and the other impurity separation device includes a rotating roller located in the flow of the mixed flow containing pulverized coal, and the rotation The roller is related to a vertical mill configured to adsorb and separate impurities in pulverized coal by magnetic force.

  Further, the present invention relates to a vertical mill in which the rotating roller is composed of a plurality of disc-shaped magnets that are mounted on a rotating shaft at predetermined intervals.

  Further, the present invention relates to a vertical mill in which the rotating roller has a cylindrical shape and an outer peripheral surface is a magnet.

  According to the present invention, the rotating roller has an electromagnet divided into a plurality of portions in the circumferential direction. The electromagnets can be independently excited and de-energized, and are sequentially de-energized at a position deviated from the mixed flow. The present invention relates to a vertical mill configured as described above.

  According to the present invention, a pulverizing table provided at the lower part of the classification chamber, a pressure roller that is pressed against the pulverizing table and rolled, and an upper part of the classification chamber, the pulverized pulverized coal is mixed with air. A classifier disposed so as to pass through, a pulverized coal feeding pipe for sending an air mixed stream of classified pulverized coal, and an impurity separation device provided in the pulverized coal feeding pipe, The impurity separation device includes a first magnet provided around the pulverized coal feed pipe, and a second magnet located on the downstream side of the first magnet and provided at a part of the circumference of the pulverized coal feed pipe. A magnet and a branch pipe communicating with the pulverized coal feed pipe on the downstream side of the second magnet, the first magnet forms an excitation area, the second magnet forms an attraction area, Exciting impurities in the pulverized coal passing through the excitation region, and the excited impurities are separated from the branch pipe by the suction region Induction and separation of impurities eliminates the need for a coal pulverizing function and power as an impurity separation device, reducing running costs and pulverizing the particle size sufficiently with a vertical mill. Is done effectively. Furthermore, since the impurities are separated and removed before burning the coal, a denitration device, a dust collection device, a desulfurization device, etc., which are exhaust gas treatment devices, are not required, and the equipment cost is reduced.

  According to the present invention, the second magnet is provided at the upper end of the pulverized coal feed pipe, and the branch pipe separates upward, so that impurities that are lighter than pulverized coal can be efficiently separated.

  According to the present invention, the second magnet is provided at the lower end of the pulverized coal feed pipe, and the branch pipe is separated downward, so that impurities heavier than pulverized coal can be efficiently separated.

  Further, according to the present invention, two sets of impurity separation devices are connected to the pulverized coal feeding pipe, and one impurity separation device has the second magnet provided at an upper end portion of the pulverized coal feeding pipe, The branch pipe is configured to be separated upward, and the other impurity separation device is configured such that the second magnet is provided at a lower end portion of the pulverized coal feeding pipe, and the branch pipe is separated downward. Since it is configured, impurities that are lighter and heavier than pulverized coal can be efficiently separated.

  Also, according to the present invention, the excitation region portion and the suction region portion of the pulverized coal feed pipe are made larger in diameter than the pulverized coal feed tube, and the air mixture flowing through the excitation region portion and the suction region portion is mixed. Since the flow velocity of the flow is reduced with respect to the pulverized coal feed pipe portion, the magnetic force of the first magnet and the second magnet can be effectively applied to the impurities, the impurity separation efficiency is improved, and the coal selection efficiency Can be improved.

  Further, according to the present invention, another impurity separation device is provided adjacent to the classification chamber, and the other impurity separation device includes a rotating roller located in the flow of the mixed flow containing pulverized coal, Since the rotating roller is configured to adsorb and separate impurities in the pulverized coal by magnetic force, it can separate impurities in the classification chamber and impurities in the mixed flow containing the pulverized coal sent from the classification chamber. In addition, excellent effects such as further improving the separation efficiency of impurities and improving the efficiency of coal preparation can be achieved.

It is the schematic of the vertical mill which concerns on the Example of this invention. It is a front view of a 1st embodiment of the 1st impurity separation device. It is a side view of 1st Embodiment of a 1st impurity separation apparatus. It is a front view of 2nd Embodiment of a 1st impurity separation apparatus. It is a side view of 2nd Embodiment of a 1st impurity separation apparatus. It is a front view of 3rd Embodiment of a 1st impurity separation apparatus. It is a side view of 3rd Embodiment of a 1st impurity separation apparatus. It is the schematic of a 2nd impurity separation apparatus. It is the schematic of another 2nd impurity separation apparatus. It is the schematic of another 2nd impurity separation apparatus. It is a figure which shows the content rate of the ash content contained in coal, and the composition of ash content.

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

  FIG. 1 shows an example of a vertical mill 1 in which the present invention is implemented.

  A sealed space is formed by a casing 3 erected on the base 2, and a pulverizing table 5 is installed below the space via a table driving device 4. The pulverizing table 5 is fixed by the table driving device 4. Rotated at high speed. A table segment 7 having a concave groove 6 having a circular arc cross section is provided on the upper surface of the grinding table 5.

  A required number of sets, for example, three sets of pressure roller units 8 are provided radially from the rotation center of the crushing table 5. The pressure roller unit 8 has a pressure roller 9 and is tiltable about a horizontal support shaft 11. Further, three sets of roller pressurizing devices 12 penetrating radially are provided at the lower portion of the casing 3. The roller pressure device 12 includes an actuator, for example, a hydraulic cylinder 10, and presses the pressure roller 9 against the concave groove 6 by the hydraulic cylinder 10.

  A primary air chamber 13 is formed below the pulverization table 5, and a classification chamber 14 is provided above the pulverization table 5 inside the casing 3.

  A primary air supply port 15 is attached to the lower part of the casing 3, and the primary air supply port 15 is connected to a blower (not shown) and communicates with the primary air chamber 13. A nozzle ring 20 is provided around the crushing table 5, and a primary air outlet 16 is provided over the entire circumference of the nozzle ring 20.

  A coal supply / discharge portion 17 is provided on the upper side of the casing 3, and a pipe-like chute 18 is provided so as to penetrate the center portion of the coal supply / discharge portion 17. It extends to. Coal 23 is supplied to the chute 18, and the supplied coal 23 falls on the crushing table 5.

  A classifier 19 is rotatably provided in the middle of the chute 18, and the classifier 19 has strip-shaped blades 21 arranged at a required pitch in the circumferential direction. The classifier 19 is a rotation drive unit. (Not shown).

  A pulverized coal feed pipe 22 is connected to the coal feed / discharge part 17. The pulverized coal feed pipe 22 is connected to a boiler burner (not shown) and feeds the pulverized pulverized coal to the burner. The pulverized coal feed pipe 22 is provided with a second impurity separation device 25.

  A first impurity separation device 24 is provided below the casing 3 and above the outlet 16. The first impurity separation device 24 is provided between the roller pressure devices 12 and 12 so as not to interfere with the roller pressure device 12 and the pressure roller 9.

  First, the first impurity separation device 24 will be described.

  2 and 3 show a first embodiment of the first impurity separation device 24.

  A separation part case 26 swelled in a semicylindrical shape is provided at the lower part of the casing 3, and a rotation roller 27 is rotatably provided in the separation part case 26 via a horizontal rotation shaft 28.

  Further, a separation unit motor 29 is provided on a side surface of the separation unit case 26, and an output shaft of the separation unit motor 29 and the rotary shaft 28 are connected to each other, and the rotation roller 27 is moved by the separation unit motor 29 in FIG. It can be rotated clockwise at a predetermined speed.

  The rotating roller 27 includes a plurality of suction disks 31 mounted on the rotary shaft 28 at predetermined intervals. Each of the suction disks 31 is a permanent magnet. , 31 are arranged so that the magnetic poles are different.

  An impurity separation duct 32 is connected to the lower portion of the separation part case 26, and an impurity discharge valve, for example, a rotary, is provided at the lower end of the impurity separation duct 32 to maintain the airtightness of the classification chamber 14 and discharge impurities. A gate 33 is provided.

  An impurity scraping plate 34 is fixed to the inner surface of the impurity separation duct 32, and the impurity scraping plate 34 has a comb-like tip portion, and is inserted between the suction disks 31, 31. In this manner, both sides of the suction disk 31 are in sliding contact.

  The operation of the vertical mill 1 will be described.

  The pulverizing table 5 is rotated, and in a state where primary air is introduced from the primary air supply port 15, a massive coal 23 is introduced from the chute 18. The massive coal 23 flows down from the lower end of the chute 18 to the center of the crushing table 5 and is supplied onto the crushing table 5.

  The coal 23 on the pulverizing table 5 moves in the outer circumferential direction by centrifugal force, is pulverized and powdered by the pressure roller 9, and further moves to the outer circumference by centrifugal force. The pulverized coal overflowing from the pulverizing table 5 rises on the primary air that blows up the outlet 16.

  Primary air containing pulverized coal (referred to as a pulverized coal mixed flow) rises between the adsorption disks 31 and 31 and reaches the classification chamber 14. When the pulverized coal mixed flow flows between the adsorption disks 31, 31, the pulverized coal that is not magnetized passes without being adsorbed by the adsorption disk 31.

  Impurities contained in the coal 23 include sulfur, iron, mercury, ash, etc., and metals such as iron, mercury are combined with sulfur, and the ash is also integrated with sulfur. . Therefore, iron combined with sulfur is adsorbed by the adsorption disk 31, so that heavy metals such as mercury are also adsorbed by the adsorption disk 31 together with iron via sulfur.

  FIG. 11 shows the amount of ash contained in the coal 23 and the composition of the ash.

  As shown in FIG. 11, in the brands A to H of the coal 23, the ash content is 1.40 W% at the minimum and 10.00 W% at the maximum.

  Further, iron (Fe2 O3) is included as a composition of ash. It can be seen that the iron content is 2.56 W% at the minimum and 26.90 W% at the maximum, and the iron content is approximately 10 W% as a whole.

  Therefore, the ash can also be adsorbed by a magnet, and when the pulverized coal mixed flow passes through the rotating roller 27, the metals and ash are adsorbed on the adsorption disk 31, and impurities are separated from the coal 23. The Further, the particle size of the pulverized coal pulverized by the pressure roller 9 is as small as 30 to 50 μm, and impurities can be separated (coal selection) with high efficiency.

  Thus, pulverized coal passes through the adsorption disk 31, and impurities are adsorbed on the adsorption disk 31 and removed from the coal 23.

  The suction disk 31 is rotated by the separation motor 29, and impurities are scraped from the suction disk 31 by the impurity scraping plate 34 by the rotation of the suction disk 31.

  The scraped impurities are guided to the impurity separation duct 32 by the impurity scraping plate 34, temporarily stored in the impurity separation duct 32, and rotated by a valve body (not shown) of the rotary gate 33. Impurities are discharged intermittently. Accordingly, the removal of impurities from the pulverized pulverized coal is carried out continuously and permanently.

  The first impurity separation device 24 does not exist in the portion of the pressure roller 9, but in the region where the pressure roller 9 presses the pulverized coal layer, the outer periphery of the pulverized coal is pressed by the pressure roller 9. Since the movement to the side is constrained, even if the first impurity separation device 24 does not exist in the portion of the pressure roller 9, there is no hindrance to the impurity separation from the pulverized coal as a whole.

  The pulverized coal from which impurities are removed and rises in the classification chamber 14 is classified by the classifier 19, pulverized coal of a predetermined particle or more falls on the pulverizing table 5, and the pulverized coal of a predetermined particle or less is pulverized coal. It is sent out from the feed pipe 22.

  4 and 5 show a second embodiment of the first impurity separation device 24. In addition, in the figure, the same code | symbol is attached | subjected to the thing equivalent to what was shown in FIG. 2, FIG.

  In the first impurity separation device 24, the rotating roller 27 is a cylindrical drum 35 and the outer peripheral surface of the cylindrical drum 35 is a magnet, and the impurity scraping plate 34 is in sliding contact with the outer peripheral surface of the cylindrical drum 35. Is provided.

  Also in the first impurity separation device 24, impurities adhere to the outer peripheral surface and are scraped off by the impurity scraping plate 34, and the scraped impurities are further transferred to the impurity separation duct 32 by the impurity scraping plate 34. Led.

  6 and 7 show a third embodiment of the first impurity separation device 24. In addition, in the figure, the same code | symbol is attached | subjected to the thing equivalent to what was shown in FIG. 2, FIG.

  In the first impurity separation device 24, the rotating roller 27 is composed of a plurality of electromagnets 36 (four in the figure, 36a, 36b, 36c, 36d).

  An electromagnet 36a, 36b, 36c, 36d is attached to the surface of a hollow cylindrical drum, and an excitation coil (not shown) for exciting and de-energizing the electromagnets 36a, 36b, 36c, 36d independently inside the hollow drum. And a switching circuit (not shown) for switching the energization state of the exciting coil.

  The impurity scraping plate 34 attached to the impurity separation duct 32 is in sliding contact with the outer peripheral surface of the rotating roller 27.

  The rotating roller 27 is rotated by a separation unit motor 29, and among the electromagnets 36a, 36b, 36c and 36d, three electromagnets 36 are excited and one electromagnet 36 is not excited.

  In the drawing, the electromagnet 36a is not excited, and the electromagnets 36b, 36c, and 36d are excited. Accordingly, impurities are adsorbed on the electromagnets 36b, 36c, and 36d, but not adsorbed on the electromagnet 36a.

  The rotating roller 27 is continuously rotated, and when the electromagnet 36b comes to the position of the illustrated electromagnet 36a, that is, the electromagnet 36b comes out of the pulverized coal mixed flow and comes close to the impurity separation duct 32, the energization is stopped. Is de-excited. Further, the electromagnet 36a is excited at a position beyond the impurity scraping plate 34. Impurities are released from the non-excited electromagnet 36b, fall onto the impurity scraping plate 34, and are guided to the impurity separation duct 32. Further, when the electromagnet 36a is excited, impurities are attracted to the electromagnet 36a.

  Thus, the excitation and non-excitation of the electromagnets 36a, 36b, 36c, and 36d are sequentially repeated, so that impurities are adsorbed and collected, and separated and removed from the pulverized coal.

  The position where the first impurity separation device 24 is provided is preferable because the dense pulverized coal mixed flow and the rotary roller 27 are in contact between the pressure rollers 9 and 9 and above the outlet 16. However, what is necessary is just to be provided in the flow path of a pulverized coal mixed flow, and an impurity can be separated and removed from pulverized coal by the structure which contacts a pulverized coal mixed flow and a magnet.

  Further, the separation portion case 26 may be detachable from the casing 3 so that the rotation roller 27 can be easily replaced and maintained.

  Next, the second impurity separation device 25 will be described with reference to FIG.

  The second impurity separation device 25 removes impurities from the pulverized coal mixed stream sent from the vertical mill 1, and the first impurity separation device 24 and the second impurity separation device 25 perform two stages. To remove impurities.

  The second impurity separation device 25 is provided in a straight portion of the pulverized coal feed pipe 22 or a loosely curved portion.

  The pulverized coal feed pipe 22 is branched by a main pipe 38 and a branch pipe 39 communicating with the pulverized coal feed pipe 22, and the main pipe 38 has a pipe axis parallel to the pulverized coal feed pipe 22. And after branching, it functions as a pulverized coal feed pipe 22 for feeding pulverized coal. The main pipe 38 has a diameter D2 (D1 ≧ D2) smaller than the pipe diameter D1 of the pulverized coal feed pipe 22, and the pipe axis of the main pipe 38 is the pulverized coal feed pipe. The lower end of the pulverized coal feed pipe 22 and the lower end of the main pipe 38 are the same.

  The branch pipe 39 has a diameter D3 (D1 ≧ D2 ≧ D3) smaller than the pipe diameter D2 of the main pipe 38, and has an acute angle α (for example, 5 ° to 30 ° with respect to the pulverized coal feed pipe 22). The branch point 41 is at a height D2 from the lower end of the pulverized coal feed pipe 22. A branch flow rate may be adjusted by providing a flow rate adjusting valve 48 in the branch pipe 39.

  A first magnet 42 is disposed upstream of the branch point 41, and a second magnet 43 is disposed downstream of the first magnet 42.

  The first magnet 42 has a cylindrical shape surrounding the entire circumference of the pulverized coal feed pipe 22, and the second magnet 43 surrounds a required range in the circumferential direction around the upper end of the pulverized coal feed pipe 22. It has a shape having an arc cross section, and preferably has a substantially semi-cylindrical shape surrounding the upper half of the pulverized coal feed pipe 22.

  The first magnet 42 forms an excitation region for exciting impurities that pass through the first magnet 42. Further, the second magnet 43 forms a suction region for sucking the excited impurities to the upper part of the pulverized coal feed pipe 22.

  The magnet used for the first magnet 42 and the second magnet 43 may be a permanent magnet or an electromagnet. Moreover, when using a permanent magnet, a strong magnetic force can be obtained by connecting the divided magnets.

  Hereinafter, the operation of the second impurity separation device 25 will be described.

  The pulverized coal mixed stream delivered from the vertical mill 1 contains impurities that could not be removed by the first impurity separation device 24, and these impurities are excited when passing through the first magnet 42. Further, when passing through the second magnet 43, it is attracted to the second magnet 43 side.

  At the time of passing through the first magnet 42, the attractive force of the second magnet 43 acts effectively by exciting the impurities. By passing through the second magnet 43, the impurities are attracted to the second magnet 43 and further diverted by the branch point 41, and the impurities are separated from the pulverized coal.

  The position of the branch point 41, that is, (D1-D2) is appropriately selected depending on the speed of the pulverized coal mixed flow, the strength of the second magnet 43, and the like. For example, if the magnetic force of the second magnet 43 is sufficiently strong and can be diverted only by the magnetic force, the values of D1 and D2 are made equal (D1-D2 = 0).

  Further, since the branch pipe 39 communicates with the upper side of the pulverized coal feed pipe 22, it is suitable for separating those having a specific gravity of impurities that is lighter than that of the pulverized coal.

  The second impurity separation device 45 shown in FIG. 9 is one in which the branch pipe 39 is communicated with the lower side of the pulverized coal feed pipe 22, and in this case, the impurities are separated downward, so that the separation action is performed. Gravity is added. Accordingly, the second impurity separation device 45 is suitable when the specific gravity of impurities is larger than that of pulverized coal. Further, in order to use centrifugal force acting on impurities for separation, the second impurity separation device 45 may be provided in the curved portion, and the branch pipe 39 may be communicated with the outer peripheral side.

  The second impurity separation device 25 and the second impurity separation device 45 can be combined. For example, by providing the second impurity separation device 25 on the upstream side and the second impurity separation device 45 on the downstream side, the second impurity separation device 25 separates lighter than pulverized coal, and the second impurity The separator 45 can separate the heavier than pulverized coal, improving the efficiency of coal preparation.

  Since the second impurity separation device 25 and the second impurity separation device 45 are provided in the middle of the piping, they can be easily provided in addition to existing facilities. A branch flow rate may be adjusted by providing a flow rate adjusting valve 48 in the branch pipe 39.

  Next, FIG. 10 shows another embodiment of the second impurity separation device.

  The second impurity separation device 46 shown in FIG. 10 is such that the portion of the pulverized coal feed pipe 22 where the first magnet 42 and the second magnet 43 are provided has a partially large diameter.

  By using a large diameter, the flow rate of the pulverized coal mixed flow that passes through the excitation area and the suction area decreases, the passage time of the excitation area and the suction area becomes longer, the excitation action and the suction action against impurities increase, and the separation effect Will increase.

  Although the first magnet 42 and the second magnet 43 are provided separately, they may be provided continuously, or the branch pipe 39 may be provided with a flow rate adjustment valve 48 to adjust the branch flow rate. . Furthermore, it is possible to provide only the second impurity separation device 25 or only the first impurity separation device 24. In this case, it goes without saying that the efficiency of coal selection is improved.

DESCRIPTION OF SYMBOLS 1 Vertical mill 3 Casing 5 Grinding table 9 Pressure roller 12 Roller pressurization device 14 Classification chamber 16 Outlet 24 First impurity separation device 25 Second impurity separation device 26 Separation part case 27 Rotating roller 31 Adsorption disk 32 Impurity separation Duct 33 Rotary gate 34 Impurity scraping plate 35 Cylindrical drum 36 Electromagnet 38 Main pipe 39 Branch pipe 41 Branch point 42 First magnet 43 Second magnet 45 Second impurity separator 46 Second impurity separator

Claims (9)

  A crushing table provided at the lower part of the classification chamber, a pressure roller that is pressed and rolled by the crushing table, and disposed at the upper part of the classification chamber so that the pulverized pulverized coal passes as an air mixed flow. A classified classifier, a pulverized coal feeding pipe for sending an air mixed stream of classified pulverized coal, and an impurity separation device provided in the pulverized coal feeding pipe, the impurity separation device comprising: A first magnet provided around the pulverized coal feed pipe; a second magnet located downstream of the first magnet and provided at a part of the circumference of the pulverized coal feed pipe; A branch pipe communicating with the pulverized coal feed pipe on the downstream side of the magnet, wherein the first magnet forms an excitation area, the second magnet forms an attraction area, and passes through the excitation area. Impurities in the charcoal are excited, and the excited impurities are guided to the branch pipe by the suction region. Vertical mill and separating the.   The vertical mill according to claim 1, wherein the second magnet is provided at an upper end portion of the pulverized coal feeding pipe, and the branch pipe is separated upward.   The vertical mill according to claim 1, wherein the second magnet is provided at a lower end portion of the pulverized coal feed pipe, and the branch pipe is separated downward.   Two sets of impurity separation devices are connected to the pulverized coal feed pipe. One impurity separation device has the second magnet provided at the upper end of the pulverized coal feed pipe, and the branch pipe faces upward. The other impurity separation device is configured such that the second magnet is provided at a lower end portion of the pulverized coal feed pipe, and the branch pipe is separated downward. Vertical mill.   The excitation region portion and the suction region portion of the pulverized coal feed pipe are made larger in diameter than the pulverized coal feed tube, and the flow velocity of the air mixed flow flowing through the excitation region portion and the suction region portion is set as the pulverized coal. The vertical mill according to claim 1, wherein the vertical mill is reduced with respect to a feeding pipe portion.   Another impurity separation device is provided adjacent to the classification chamber, and the other impurity separation device includes a rotating roller positioned in the flow of the mixed flow containing pulverized coal, and the rotating roller is finely divided by magnetic force. The vertical mill according to claim 1, wherein the vertical mill is configured to adsorb and separate impurities in the charcoal.   The vertical mill according to claim 6, wherein the rotating roller is composed of a plurality of disc-shaped magnets mounted on a rotating shaft at predetermined intervals.   The vertical mill according to claim 6, wherein the rotating roller has a cylindrical shape and an outer peripheral surface is a magnet.   The rotating roller has a plurality of electromagnets equally divided in the circumferential direction, and the electromagnets can be independently excited and de-energized and are sequentially de-energized at positions deviating from the mixed flow. The vertical mill according to claim 6.

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