JP5412800B2 - Vertical pulverized coal mill - Google Patents

Description

The present invention relates to a vertical pulverized coal 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 pulverized coal 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 incombustibles is 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 practical pulverization 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 a situation, the present invention provides a vertical pulverized coal mill that does not require water and that does not generate dust and that can perform fine coal pulverization to perform efficient coal selection.

In the present invention, a plurality of pressure rollers are pressed against a rotating pulverizing table to pulverize coal, and a blow-off port is provided around the pulverizing table. Air is blown from the blow-off port, and the pulverized coal is pulverized. In a vertical pulverized coal mill that is adapted to be blown up, an impurity separation device having a rotating roller located in a mixed flow containing pulverized coal is provided, and the rotating roller is magnetically pulverized coal. It relates to a vertical pulverized coal mill configured to adsorb and separate impurities therein, and the rotating roller is related to a vertical pulverized coal mill disposed so as to be positioned above the outlet. is there.

According to the present invention, a separation part case that bulges outside is provided at a lower part of a casing that accommodates the pulverization table and the pressure roller, and the rotating roller is accommodated in the separation part case. And an impurity separation duct. The vertical pulverized coal mill is provided with an impurity scraping plate so as to be brought into sliding contact with the rotating roller, scraping the adsorbed impurities, and leading to the impurity separation duct.

The present invention also relates to a vertical pulverized coal mill comprising a plurality of disc-shaped magnets mounted on a rotating shaft at a predetermined interval. The rotating roller has a cylindrical shape and has an outer periphery. The present invention relates to a vertical pulverized coal mill whose surface is a magnet, and further, the rotating roller has an electromagnet divided into a plurality of equal parts in the circumferential direction, and the electromagnet can be independently excited and de-excited. The present invention relates to a vertical pulverized coal mill configured to be sequentially de-excited at a position deviating from the mixed flow.

According to the present invention, coal is pulverized by pressing a plurality of pressure rollers against a rotating pulverization table, and an outlet is provided around the pulverization table, and air is blown from the outlet and pulverized fine powder. In a vertical pulverized coal mill in which charcoal is blown up, an impurity separation device having a rotating roller located in a mixed flow containing pulverized coal is provided, and the rotating roller is magnetically Since it is configured to adsorb and separate impurities in pulverized coal, an impurity separation device is provided integrally with the vertical pulverized coal mill, and the impurity separation device does not require the function and power to pulverize coal. Further, since the running cost is reduced and the particle size is sufficiently pulverized by the vertical pulverized coal mill, the impurities are effectively separated. 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, a separation part case that bulges outside is provided at a lower part of a casing that accommodates the pulverization table and the pressure roller, and the rotating roller is accommodated in the separation part case. An impurity separation duct is provided at the bottom of the substrate and is in sliding contact with the rotating roller to scrape the adsorbed impurities, and an impurity scraping plate is provided to guide the impurities to the impurity separation duct. In addition, impurities can be permanently separated and recovered.

  According to the present invention, the rotating roller is composed of a plurality of disc-shaped magnets that are mounted on the rotating shaft at predetermined intervals, so that the contact area between the mixed flow and the magnet can be increased, and impurities can be efficiently collected. Can be adsorbed.

  According to the invention, the rotating roller has an electromagnet divided into a plurality of parts in the circumferential direction, and the electromagnets can be independently excited and de-energized, and are sequentially non-excited at positions deviated from the mixed flow. Since it is configured to be excited, it exhibits excellent effects such as easy separation and recovery of impurities.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a vertical pulverized coal mill 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 crushing table 5, and a classification chamber 14 is formed above the crushing 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. Around the pulverizing table 5, primary air outlets 16 are provided on the entire circumference.

  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 for feeding the pulverized coal pulverized to a boiler burner is connected to the coal supply / discharge section 17.

  An impurity separation device 25 is provided at the lower part of the casing 3 and above the outlet 16. The impurity separation device 25 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.

  A first embodiment of the impurity separation device 25 will be described with reference to FIGS.

  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 pulverized coal 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 mixed flow) rises between the adsorption disks 31 and 31 and reaches the classification chamber 14. When the mixed flow flows between the adsorption disks 31, 31, 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, by iron combines with the sulfur is adsorbed into the adsorbing disc 31 is adsorbed before Symbol suction disc 31 heavy metals such as mercury be interposed sulfur iron co.

  Next, the amount of ash contained in the coal 23 and the composition of the ash are shown in FIG.

  As shown in FIG. 8, 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 the magnet, and the metal and ash are adsorbed on the adsorption disk 31 and the impurities are separated from the coal 23 by passing the mixed flow through the rotating roller 27. 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.

  Next, the adsorption disk 31 is rotated by the separation motor 29, and impurities are scraped from the adsorption disk 31 by the impurity scraping plate 34 by the rotation of the adsorption 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 impurity separation device 25 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 pressure roller 9 moves to the outer peripheral side of the pulverized coal. Therefore, even if the impurity separation device 25 does not exist in the pressure roller 9, there is no problem in separating impurities from 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 impurity separation device 25. 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 impurity separation device 25, 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 provided so as to be in sliding contact with the outer peripheral surface of the cylindrical drum 35. It has been.

  Also in this impurity separation device 25, impurities adhere to the outer peripheral surface, and are scraped off by the impurity scraping plate 34, and the scraped impurities are guided to the impurity separation duct 32 by the impurity scraping plate 34. .

  6 and 7 show a third embodiment of the impurity separation device 25. 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 impurity separation device 25, the rotating roller 27 is constituted by a plurality of electromagnets 36 (four in the figure, 36a, 36b, 36c, 36d).

  Electromagnets 36a, 36b, 36c, 36d are mounted on the surface of a hollow cylindrical drum, and inside the hollow drum, excitation coils for energizing and de-energizing the electromagnets 36a, 36b, 36c, 36d independently are housed. A switching circuit for switching the energization state to the exciting coil is housed.

  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 mixed flow and comes close to the impurity separation duct 32, the energization is stopped, 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 impurity separation device 25 is provided is preferable because the dense mixed flow and the rotating roller 27 are in contact with each other between the pressure rollers 9 and 9 and above the outlet 16. It is only necessary to be provided in the flow path, and impurities can be separated and removed from the pulverized coal with a configuration in which the mixed flow is brought into contact with the 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.

As described above, according to the present invention, the impurity separation device is provided integrally with the vertical pulverized coal mill, and the impurity separation device does not require the function and power of pulverizing coal, and the running cost is reduced. Moreover, since the particle size is pulverized sufficiently by the vertical pulverized coal mill, the separation of impurities is effectively performed. Furthermore, since impurities are separated and removed before the coal is burned, a denitration device, a dust collection device, a desulfurization device, etc., which are exhaust gas treatment devices after combustion, are not required as boiler equipment, and the equipment cost is reduced.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vertical pulverized coal mill 3 Casing 5 Grinding table 9 Pressure roller 12 Roller pressurization device 14 Classification chamber 16 Outlet 25 Impurity separation device 26 Separating part case 27 Rotating roller 31 Adsorption disk 32 Impurity separation duct 33 Rotary gate 34 Impurity Scraping plate 35 cylindrical drum 36 electromagnet

Claims (6)

A plurality of pressure rollers are pressed against the rotating crushing table to crush the coal, and a blowout port is provided around the crushing table. Air is blown out from the blowout port so that the pulverized pulverized coal is blown up. In the vertical pulverized coal mill, an impurity separation device including a rotating roller located in a mixed flow containing pulverized coal is provided,
Contained in the pulverized coal, wherein the metal containing iron and compounds with sulfur, by being configured as to be separated by adsorption by magnetic force by the rotating roller was the ash integrated with iron interposed sulfur and sulfur A vertical pulverized coal mill. The vertical pulverized coal mill according to claim 1, wherein the rotating roller is disposed so as to be positioned above the outlet. A separation part case that bulges outside is provided at a lower part of a casing for housing the pulverization table and the pressure roller, the rotating roller is accommodated in the separation part case, and an impurity separation duct is provided at a lower part of the separation part case. The vertical pulverized coal mill according to claim 1 or 2, wherein an impurity scraping plate is provided so as to slide on the rotating roller, scrape the adsorbed impurities, and guide the impurities to the impurity separation duct. 4. The vertical pulverized coal mill according to claim 3, wherein the rotating roller is composed of a plurality of disc-shaped magnets mounted on a rotating shaft at predetermined intervals. 4. The vertical pulverized coal mill according to claim 3, 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 pulverized coal mill according to claim 3.

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