JP6304482B2 - Fluidized bed drying apparatus and method for drying low-grade coal - Google Patents

Description

  The present invention relates to a fluidized bed drying apparatus and a method for drying low-grade coal used to dry so-called low-grade coal such as lignite and sub-bituminous coal containing a lot of moisture.

  Conventionally, as the fluidized bed drying device described above, for example, there is a fluidized bed drying device disclosed in Patent Document 1.

  This fluidized bed drying apparatus includes a fluidized bed container to which coarsely pulverized low grade coal (low grade coal pulverized by a mill) is supplied. Inside the fluidized bed container to which the coarsely pulverized low-grade coal is supplied, a heat transfer tube through which high-temperature steam flows is arranged, and fluidized gas is introduced at a predetermined flow rate from the lower part of the fluidized bed container. ing.

  In this fluidized bed container, coarsely pulverized low-grade coal is bubbled with fluidized gas vapor to form a fluidized bed, that is, the coarsely pulverized low-grade coal moves in the horizontal direction while moving up and down with bubbling steam. Thus, the coarsely pulverized low-grade coal is uniformly contacted with the heat transfer tube, and the fluidized bed coarsely pulverized low-grade coal heated by the contact with the heat transfer tube is dried in the fluidized bed container. It is discharged from the outlet toward the cooler.

JP 2011-214816 JP

  However, in the fluidized bed drying apparatus disclosed in Patent Document 1 described above, the coarsely pulverized low grade coal supplied from the mill to the fluidized bed container includes those with various particle sizes. In order to move coarsely pulverized low-grade coal with various particle sizes in the horizontal direction while moving up and down with bubbling steam, which is a fluidized gas, An amount of bubbling steam that can be bubbled is required, and the amount of energy consumption increases accordingly.

  Further, when the amount of bubbling steam is increased in this way, there is a problem that drying may not be sufficiently performed due to the amount of coarsely pulverized low-grade coal having a small particle diameter that is likely to be scattered. It has been a conventional problem to solve the problem.

  The present invention has been made paying attention to the above-mentioned conventional problems, and can move coarsely pulverized low-grade coal while reducing the amount of fluidized gas in the fluidized bed container, thereby realizing energy saving. In addition, an object of the present invention is to provide a fluidized-bed drying apparatus and a method for drying low-grade coal that can suppress scattering of coarsely pulverized low-grade coal having a small particle size.

That is, the first invention of the present application is a fluidized bed drying apparatus for drying low-grade coal, a fluidized-bed container for storing coarsely pulverized low-grade coal obtained by coarsely pulverizing the low-grade coal, and the fluidized bed A large number of heat transfer tubes through which steam arranged in a horizontal direction and parallel to each other in the interior of the container, and a fluidized gas supplied to the fluidized bed container to fluidize the coarsely pulverized low-grade coal, Fluidized gas supply means for drying the fluidized coarsely pulverized low-grade coal in contact with the multiple heat transfer tubes while traversing the array of heat transfer tubes, and the fluidized gas traversing the multiple heat transfer tubes. Gradient force generating means for causing gravity to act on the coarsely pulverized low-grade coal as an obliquely downward force from the low-grade coal supply side to the low-grade coal discharge side of the fluidized bed container, and the low-grade coal of the fluidized bed container Placed on the discharge side and above the fluidized bed container A dry coal outlet for discharging small particles dry coal of the fluidized coarsely pulverized low grade coal collected by the oblique force generating means, and the fluidized bed vessel disposed on the low grade coal discharge side of the fluidized bed vessel. A dry coal outlet for discharging large particle dry coal having an average particle size larger than that of the small particle dry coal of the fluidized coarsely pulverized low-grade coal collected by the oblique force generating means It is said.

  According to a second aspect of the present invention, the bottom surface of the fluidized bed container is formed as an inclined surface, and the inclined surface is used as the oblique force generating means. Container tilting means for tilting the entire fluidized bed container obliquely so as to tilt the bottom surface is configured as the oblique force generating means.

According to a fourth aspect of the present invention, when the low-grade coal is dried, the coarse-grade low-grade coal obtained by coarsely pulverizing the low-grade coal is supplied to a fluidized bed container and fluidized by a fluidized gas, While the fluidized coarsely pulverized low-grade coal is dried by contacting the multiple heat transfer tubes while traversing an array of the multiple heat transfer tubes through which steam flows horizontally and parallel to each other. Gravity is applied to the fluidized coarsely pulverized low-grade coal as an obliquely downward force from the low-grade coal supply side to the low-grade coal discharge side of the fluidized bed container, and the gravity is assumed to be an obliquely downward force. The fluidized coarsely pulverized low-grade coal is collected and discharged on the upper part of the fluidized bed container, and the fluidized coarsely pulverized pulverized by causing gravity to act as an oblique downward force. Small particle dryness of low-grade coal Is set to you scavenge arrangement collect large particle dry coal large average particle diameter in the lower part of the fluidized bed vessel than coal.

  In the present invention, the force in the diagonally downward direction from the low-grade coal supply side to the low-grade coal discharge side of the fluidized bed container acting on the fluidized coarsely-pulverized low-grade coal is such that the fluidized coarsely-pulverized low-grade coal is, for example, It is a gravity force acting when it is on an inclined surface exceeding the angle of repose, and the magnitude of the downward slanting force (angle of the inclined surface) is the property of fluidized coarsely pulverized low-grade coal Set accordingly.

  In the fluidized bed drying apparatus and the method for drying low-grade coal according to the present invention, the fluidized coarsely pulverized low-grade coal has a gravitational force in a diagonally downward direction from the low-grade coal supply side to the low-grade coal discharge side of the fluidized bed container. As a result, the fluidized bed easily moves from the low-grade coal supply side to the low-grade coal discharge side, and as a result, a large number of heat transfer tubes while fluidizing the coarsely pulverized low-grade coal into a fluidized bed. Thus, the amount of fluidized gas for traversing the arrangement of the above can be reduced, and energy saving is achieved accordingly.

  Further, in the fluidized bed drying apparatus and the low-grade coal drying method according to the present invention, since the amount of fluidized gas necessary for the movement of the fluidized bed from the low-grade coal supply side to the low-grade coal discharge side is small, the particle size Scattering of the coarsely pulverized low-grade coal having a small particle size is also suppressed.

  Here, an inclined surface formed by inclining the bottom surface of the fluidized bed container is used as an oblique force generating means, or a container inclination means for inclining the entire fluidized bed container is inclined so as to incline the bottom surface of the fluidized bed container. In this case, it is possible to easily create an environment in which the amount of fluidized gas can be reduced.

  In the fluidized bed drying apparatus according to the present invention, it is possible to move the coarsely pulverized low-grade coal while keeping the amount of fluidized gas small, and as a result, the amount of fluidized gas can be kept small. In addition, it is possible to suppress the scattering of the coarsely pulverized low-grade coal having a small particle diameter.

It is a schematic structure explanatory view showing one embodiment of a fluidized bed drying device concerning the present invention. It is schematic structure explanatory drawing which shows other embodiment of the fluidized bed drying apparatus which concerns on this invention.

Hereinafter, a fluidized bed drying apparatus and a method for drying low-grade coal according to the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a fluidized bed drying apparatus according to the present invention.

  As shown in FIG. 1, the fluidized bed drying apparatus 1 is a fluidized bed drying apparatus 1 that dries low-grade coal, a mill 2 that coarsely pulverizes the low-grade coal, and a low-grade coarsely pulverized by the mill 2. A fluidized bed container 10 in which charcoal is supplied through a low-grade coal inlet 11, a number of heat transfer tubes 12 through which high-temperature steam is disposed in the horizontal direction and parallel to each other in the fluidized bed container 10, and a fluidized bed container 10 is provided with a fan (fluidized gas supply means) 4 for supplying and bubbling vapor A as fluidized gas.

  In the fluidized bed drying apparatus 1, the coarsely pulverized low-grade coal in the fluidized bed container 10 is fluidized by the steam A from the fan 4, and these heat transfer pipes are transferred while traversing the arrangement of a large number of heat transfer tubes 12 through which high-temperature steam flows. The fluidized bed S is brought into contact with the heat pipe 12 and heated to be dried.

  In this case, the bottom surface of the fluidized bed container 10 is inclined (gradient force generating means) inclined obliquely downward from the low-grade coal inlet 11 (low-grade coal supply side) to the dry coal outlets 14 and 15 (low-grade coal discharge side). By forming as 13, the force in the obliquely downward direction acts on the fluidized bed S crossing the array of the large number of heat transfer tubes 12, that is, the gravity acts as the force in the obliquely downward direction.

  That is, the coarsely pulverized low-grade coal having a large average particle size in the fluidized bed S (for example, the coarsely pulverized low-grade coal having an average particle size of 1000 to 2000 μm) is slid down by the inclined surface 13, whereby the fluidized bed container 10. A large particle dry coal fluidized bed SL is collected in the lower left corner of the figure, and a coarsely pulverized low grade coal having a small average particle diameter (for example, a coarsely pulverized low grade coal having an average particle size of 300 μm or less is formed on the upper part of the dry coal fluidized bed SL The dry coal fluidized bed SS of charcoal) is collected.

  In the fluidized bed drying apparatus 1, the small particle dried coal of the dried coal fluidized bed SS heated and dried by contact with the heat transfer tube 12 in the fluidized bed container 10 is discharged from the dried coal outlet 14 of the fluidized bed container 10. On the other hand, the large particle dry coal of the dried dry coal fluidized bed SL is discharged from the dry coal outlet 15 of the fluidized bed container 10, and the small particle dry coal and the large particle dry coal thus discharged are These are mixed by a mixer (not shown) and conveyed toward a cooler (not shown).

  When the low-grade coal is dried by the fluidized bed drying apparatus 1, first, the coarsely pulverized low-grade coal generated by coarsely pulverizing the low-grade coal in the mill 2 is naturally dropped and the fluidized bed is passed through the low-grade coal inlet 11. Supply into the container 10.

  Next, the steam A is supplied to the fluidized bed container 10 by the fan 4 to fluidize the coarsely pulverized low-grade coal, and the fluidized bed S is passed through these heat transfer tubes 12 while traversing the array of the many heat transfer tubes 12 through which high-temperature steam flows. To heat.

  While the fluidized bed S is heated and dried, the coarsely pulverized low-grade coal having a large average particle size in the fluidized bed S is slid by the inclined surface 13 so that large particles are formed in the lower left corner of the fluidized bed container 10 in the figure. Of dry coal fluidized bed SL. At this time, as the coarsely pulverized low-grade coal having a large average particle size slides down on the inclined surface 13, the dry coal flow of the coarsely pulverized low-grade coal having a small average particle size is placed above the dry coal fluidized bed SL. Layer SS gathers.

  And the small particle | grain dry coal of the dry coal fluidized bed SS heated and dried by the contact with the heat exchanger tube 12 in the fluidized bed container 10 is discharged | emitted from the dry coal outlet 14 of the fluidized bed container 10, On the other hand, dried dry coal The large particle dry coal of the fluidized bed SL is discharged from the dry coal outlet 15 of the fluidized bed container 10.

  In the fluidized bed drying apparatus 1 according to this embodiment, the bottom surface of the fluidized bed container 10 is the inclined surface 13, so that gravity flows from the low grade coal inlet 11 of the fluidized bed container 10 to the fluidized coarsely pulverized low grade coal. Since it acts as a diagonally downward force toward the dry coal outlets 14 and 15, the fluidized bed S can easily move toward the dry coal outlets 14 and 15, and as a result, the coarsely pulverized low-grade coal flows. As a result, the amount of steam A for traversing the array of the large number of heat transfer tubes 12 can be suppressed while the fluidized bed S is formed, and energy saving is achieved accordingly.

  Further, in the fluidized bed drying apparatus 1 according to this embodiment, since the amount of steam A necessary for moving the fluidized bed S toward the dry coal outlets 14 and 15 is small, the coarsely pulverized low-grade coal having a small particle size is used. Scattering is also reduced.

  Furthermore, in the fluidized bed drying apparatus 1 according to this embodiment, since the inclined surface 13 of the fluidized bed container 10 is used as the oblique force generating means, an environment in which the amount of the steam A can be suppressed can be easily created.

  FIG. 2 shows another embodiment of the fluidized bed drying apparatus according to the present invention.

  As shown in FIG. 2, the fluidized bed drying apparatus 1A is different from the fluidized bed drying apparatus 1 according to the previous embodiment in that the entire fluidized bed container 10A is inclined so that the bottom surface 13A of the fluidized bed container 10A is inclined. The screw mechanism 20 as the container tilting means for tilting is used as the tilt force generating means, and the other configuration is the same as the fluidized bed drying apparatus 1 according to the previous embodiment.

  Also in the fluidized bed drying apparatus 1A according to this embodiment, the bottom surface 13A of the fluidized bed container 10A is inclined by the screw mechanism 20 so that the gravity is reduced to the fluidized coarsely pulverized low grade coal and the low grade coal of the fluidized bed container 10A. Since it acts as a diagonally downward force from the inlet 11 to the dry coal outlets 14 and 15, the fluidized bed S can easily move toward the dry coal outlets 14 and 15, and therefore, the coarsely pulverized low-grade coal As a result, the amount of steam A for traversing the arrangement of the large number of heat transfer tubes 12 can be reduced while the fluidized bed S is fluidized, and energy saving is achieved accordingly.

  Also in the fluidized bed drying apparatus 1A according to this embodiment, since the amount of steam A required for moving the fluidized bed S toward the dry coal outlets 14 and 15 is small, the coarsely pulverized low quality with a small particle size is sufficient. The scattering of charcoal will be reduced.

  Furthermore, in the fluidized bed drying apparatus 1A according to this embodiment, since the screw mechanism 20 as the container tilting means for tilting the entire fluidized bed container 10A is used as the tilt force generating means, the environment in which the amount of the steam A can be suppressed to be small. Can be easily created, and the inclination angle of the bottom surface 13A can be easily changed.

  The configuration of the fluidized bed drying apparatus and the low-grade coal drying method according to the present invention is not limited to the configuration of the above-described embodiment, and other configurations include, for example, small particle dry coal of the dry coal fluidized bed SS. In addition, a dry coal outlet for discharging both the large particle dry coal of the dry coal fluidized bed SL in a lump may be installed in the lower left corner of the fluidized bed container 10 in FIG. The entire fluidized bed container 10A may be inclined obliquely.

1,1A Fluidized bed dryer 4 Fan (fluidized gas supply means)
10, 10A Fluidized bed vessel 11 Low grade coal inlet (low grade coal supply side)
12 Heat Transfer Tube 13 Inclined Surface (Gradient Force Generation Means)
13A Bottom surface of fluidized bed container 14, 15 Dry coal outlet (low-grade coal discharge side)
20 Screw mechanism (container tilting means; oblique force generating means)
A Steam (fluidized gas)
S fluidized bed

Claims (4)

A fluidized bed drying device for drying low-grade coal,
A fluidized bed container for storing coarsely pulverized low-grade coal obtained by coarsely pulverizing the low-grade coal;
A number of heat transfer tubes through which steam is disposed horizontally and parallel to each other inside the fluidized bed container;
The fluidized gas is supplied to the fluidized bed container to fluidize the coarsely pulverized low-grade coal, and the fluidized coarsely-pulverized low-grade coal is fluidized to the multiple heat transfer tubes while traversing the array of the multiple heat transfer tubes. Fluidized gas supply means for contacting and drying,
A slant that causes gravity to act on the fluidized coarsely pulverized low-grade coal traversing the array of the plurality of heat transfer tubes as a downward force from the low-grade coal supply side to the low-grade coal discharge side of the fluidized bed container. Force generating means;
Dry coal which is disposed on the low-grade coal discharge side of the fluidized bed container and discharges the fluidized coarsely pulverized low-grade coal small particle dry coal collected by the oblique force generating means on the fluidized bed container. Exit,
Average particle size than the small particle dry coal of the fluidized coarsely pulverized low grade coal disposed on the low grade coal discharge side of the fluidized bed vessel and collected by the oblique force generating means at the bottom of the fluidized bed vessel A fluidized bed drying apparatus comprising: a dry coal outlet for discharging large particle dry coal having a large diameter .   The fluidized bed drying apparatus according to claim 1, wherein the inclined surface is used as the oblique force generating means by forming the bottom surface of the fluidized bed container as an inclined surface.   The fluidized bed drying apparatus according to claim 1, wherein the tilting force generating means is a container tilting means for tilting the entire fluidized bed container so as to tilt the bottom surface of the fluidized bed container. When drying low-grade coal,
The coarsely pulverized low-grade coal obtained by coarsely pulverizing the low-grade coal is supplied to a fluidized bed container and fluidized by a fluidized gas,
Inside the fluidized bed container, the fluidized coarsely pulverized low-grade coal is contacted with the fluidized coarsely pulverized low-grade coal while traversing an array of a plurality of heat transfer tubes through which steam is disposed in a horizontal direction and parallel to each other. While making the fluidized coarsely pulverized low-grade coal, gravity acts as an oblique downward force from the low-grade coal supply side to the low-grade coal discharge side of the fluidized bed container ,
By causing gravity to act as an obliquely downward force, the fluidized coarsely pulverized low-grade coal small particle dry coal is collected and discharged at the top of the fluidized bed container, and the gravity is caused to act as an obliquely downward force. wherein the small particles dry coal drying method of the low-grade coal you collect and discharge large particle dry coal average particle diameter is large at the bottom of the fluidized bed vessel than the fluidized roughly pulverized low rank coal by.

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