JP2005028249A - Method and device for recovering pulverized coal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for recovering pulverized coal by which the use of a flotation machine can be eliminated and the process can be shoryened. <P>SOLUTION: The method for recovering the pulverized coal from a coal slurry containing the pulverized coal comprises: a stage where a scavenger A and a foaming agent B are added to coal slurry S1; a shearing stage where the coal slurry containing the scavenger A and the foaming agent B is rapidly stirred to impart a shearing force to the pulverized coal (c) and oil droplets (a) in the scavenger; and a floatation stage where the foaming agent B is foamed, and simultaneously, the pulverized coal (c) whose surface has been reformed by the shearing treatment is floated by utilizing foam (b) in the foaming agent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for collecting pulverized coal, and more particularly to a method and apparatus for collecting pulverized coal (fine coal) from pulverized coal-water slurry (coal slurry) formed by adding water to pulverized coal. It is.
[0002]
[Prior art]
For the selection of coal, the selection method differs depending on the particle size. For example, pulverized coal of 0.5 mm or less is selected (collected) by the flotation method.
[0003]
Conventionally, as one of the flotation methods, for example, as shown in FIG. 7, (1) a step of pulverizing raw coal 1 with a pulverizer 2 and (2) introducing the obtained pulverized coal 3 into a mixing tank 4 Then, a step of adding a binder 5 and water 6 to form a water slurry of pulverized coal, and (3) sending the water slurry of pulverized coal to a horizontal cylindrical granulator 7 having a stirring blade, A step of deashing and granulating, (4) a step of adjusting the concentration of the microgranulated coal by adding water 10 after introducing the obtained slurry of the microgranulated coal into the conditioner 8, and (5) A step of adding a foaming agent or a flotation agent 9 mainly composed of a foaming agent to the finely granulated coal slurry after the concentration adjustment; and (6) the microgranulated coal after the addition of the foaming agent or the flotation agent 9 Proposed a flotation recovery method that consists of a step of flotation of fine granulated coal by introducing the slurry into the flotation machine 11 Is (e.g., see Patent Document 1.).
[0004]
[Patent Document 1]
JP-A-60-122065 (page 2, upper left column, line 20 to page 3, upper right column, line 15, line 1)
[0005]
[Problems to be solved by the invention]
According to the above floating recovery method, the microgranulated coal 12 is relatively more hydrophobic than the case of the coal alone due to the added binder, so that the foaming agent or the foaming agent is the main component. It adheres to the bubbles generated by the flotation agent and floats on the water surface. On the other hand, the ash 13 in the coal is more hydrophilic than the carbon, so it sinks without floating. If the floated fine granulated coal 12 is collected by a flotation machine as in the normal flotation method, the fine granulated coal 14 with less ash content can be obtained.
[0006]
However, the above-described floating recovery method has a problem that the collection and sorting of pulverized coal is performed by the flotation machine 11, and thus the collection and sorting of pulverized coal depends on the performance of the flotation machine 11. Moreover, since the above floating recovery method is composed of the six steps (1) to (6) as described above, it is desired to shorten the steps.
[0007]
The present invention has been made to solve such problems, and an object of the present invention is to provide a method and an apparatus for recovering pulverized coal that can reduce the use of a flotation machine and the shortening of processes. It is in.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the method for recovering pulverized coal according to the present invention is a method for recovering pulverized coal from a coal slurry containing pulverized coal. In the method for recovering pulverized coal, a collecting agent and a foaming agent are added to the coal slurry. A step of adding, a sharing step of rapidly stirring the coal slurry containing the scavenger and the foaming agent to impart shear force to the pulverized coal and oil droplets of the scavenger, and foaming the foaming agent At the same time, the pulverized coal whose surface is modified by the shearing process is floated by using the bubbles of the foaming agent.
[0009]
Here, pulverized coal refers to coal having a size of about 0.5 mm or less that makes specific gravity selection impossible.
[0010]
In addition, the rapid stirring is for a gentle stirring with conventional conditioners, stirring energy refers to a 10 kW / ^{m 3} or more, ^{preferably, 25kW / m 3 ~100kW / m} 3.
[0011]
That is, the conventional conditioner is stirring for homogenizing the slurry for the purpose of preventing sedimentation of pulverized coal, and is performed gently, for example, at a stirring energy of about several kW / m ³ , whereas in the present invention Rapid stirring forces pulverized coal particles and oil droplets of flotation oil to the fixed part (drum cylindrical wall surface, partition plate, fixed blade) or moving part (stirring plate, stirring blade) in the container (drum). In order to improve the flotation properties of the surface of the pulverized coal by applying a shearing force to the surface of the pulverized coal and attaching or spreading oil droplets on the surface of the particles of the pulverized coal, high agitation energy is used.
[0012]
According to the pulverized coal recovery method of the present invention, shearing active surfaces are formed on the particles of pulverized coal and oil droplets of the flotation oil by shearing (giving shearing force) of rapid stirring, and by generating this shearing active surface, Although it is transient, surface energy rises relatively. By this increase in surface energy, an oil film can be formed on the surface of the pulverized coal due to the association between the pulverized coal and the oil droplets.
[0013]
If desired, a trapping agent and a foaming agent can be simultaneously added to the coal slurry. Moreover, a foaming agent can be added to the coal slurry which added the collection agent to coal slurry, and mixed the collection agent after an appropriate time.
[0014]
Further, the addition amount of the collecting agent is preferably 0.01 to 1.0% by weight, more preferably 0.05 to 0.3% by weight, based on the amount of pulverized coal.
[0015]
On the other hand, the addition amount of the foaming agent is preferably 50 to 1000 ppm, more preferably 100 to 200 ppm, based on the amount of pulverized coal.
[0016]
And the collection apparatus of the pulverized coal used in order to implement said pulverized coal collection method is comprised as follows.
[0017]
That is, the pulverized coal recovery device of the present invention is a pulverized coal recovery device that recovers pulverized coal from a coal slurry containing pulverized coal, the means for adding a collecting agent and a foaming agent to the coal slurry, A pulverized coal surface reformer that foams the foaming agent at the same time as applying a shearing force to the oil droplets of the pulverized coal and the collection agent by rapidly stirring the coal slurry containing the collection agent and the foaming agent; The pulverized coal surface reformer comprises a floating sorting tank that floats the pulverized coal whose surface has been modified using bubbles of a foaming agent.
[0018]
Here, the pulverized coal surface reformer has a multi-stage donut-shaped partition plate in the longitudinal direction of the drum in a cylindrical drum, and in the stirring chamber surrounded by the partition plate, A stirring plate with stirring blades for rapidly stirring the coal slurry is provided, and among the partition plates, fixed blades are provided on the wall surface of the partition plate in the strong stirring region on the drum upstream side.
[0019]
The present invention also includes means for simultaneously adding a scavenger and a foaming agent to the coal slurry.
[0020]
Furthermore, this invention is equipped with the collection agent addition means which adds a collection agent to coal slurry, and the foaming agent addition means which adds a foaming agent to the coal slurry in which the collection agent was mixed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a pulverized coal recovery apparatus according to the present invention, in which a slurry adjustment tank 21, a slurry pump 22, a collecting agent addition apparatus 23, a foaming agent addition apparatus 24, and a pulverized coal surface reformer 25 are illustrated. The floating sorter 26 is configured.
[0022]
Here, the foaming agent addition device 24 is located on the downstream side of the collection agent addition device 23, and after adding the collection agent A to the coal slurry S1 by the collection agent addition device 23, the coal slurry S1 is added. Foaming agent B is added.
[0023]
The collecting agent adding device 23 is composed of a collecting agent tank 27 and a quantitative supply pump 28, and the foaming agent adding device 24 is composed of a foaming agent tank 29 and a quantitative supply pump 30.
[0024]
The pulverized coal surface reformer 25 is configured as a horizontal multistage high-speed mixer, as shown in FIG. The horizontal multistage high-speed mixer 25 includes a drum 41 supported on a base by a support leg (not shown), a motor 61 and a speed reducer (not shown), and a rotating shaft 51 driven by the motor 61. By rotating the stirring plate 52 provided at a high speed, the particles c of the pulverized coal in the coal slurry S1 and the oil droplets a of the collecting agent are brought into contact with the drum inner cylinder wall surface 41a, the partition plate 42, the stirring plate 52, and the like. The pulverized coal is modified by applying shearing force.
[0025]
More specifically, in the pulverized coal surface reformer 25, as shown in FIG. 2, partition plates (baffles) 42 are provided in the drum 41 at substantially equal intervals in the axial direction of the drum 41. The partition plate 42 is formed in a donut plate shape in which two upper and lower semicircular arc plates are arranged to face each other, and the outer peripheral side is fixed to the cylindrical wall surface 41a of the drum 41, and the coal slurry S1 and the collecting agent A at the center. And the flow path 43 for the mixture S2 of the foaming agent B and the air E to distribute | circulate is provided. The reason why the partition plate 42 is made of two upper and lower semicircular arc plates is to facilitate assembly and disassembly.
[0026]
Further, in the partition plates 42 a and 42 b provided in the vicinity of the inlet 44 of the coal slurry S 1, that is, the partition plates 42 a and 42 b in the strong agitation zone M, strip-shaped or rectangular fixed blades 48 project from the partition plate 42. ing. Specifically, the first partition plate 42a is provided with fixed blades 48 on both surfaces thereof, and the second partition plate 42b has a plurality of, for example, three fixed blades 48 on only one surface on the inlet 44 side. Provided (see FIG. 3). Note that the symbol N is a separation zone.
[0027]
A rotating shaft 51 pivotally supported by bearings 46 on both sides of the drum 41 is disposed inside the drum 41, and the rotating shaft 51 has a stirring blade 53 as shown in FIG. The plate 52 is fitted through the boss portion 52a. The stirring plate 52 is provided perpendicular to the axial direction of the rotating shaft 51 and is disposed at substantially equal intervals in the axial direction of the rotating shaft 51. Thereby, when the stirring plate 52 is disposed in the drum 41, each stirring plate 52 is disposed in each stirring chamber 50 partitioned by the partition plate 42.
[0028]
In order to give a sufficient shearing force to the coal component (pulverized coal) c and the oil droplets a of the collecting agent, the gap between the stirring blade 53 and the fixed blade 48 is desirably as narrow as possible.
[0029]
Further, in order to increase the stirring efficiency, the stirring blade 53 is formed so that the belt-like bodies that are convex and radial with respect to the rotation direction R are substantially perpendicular to the stirring plate 52 on both sides of the stirring plate 52. That is, it is provided so as to be in the axial direction of the rotating shaft 51. A plurality of stirring blades 53 (four in FIG. 4) are provided at substantially equal intervals in the rotational direction of the rotating shaft 51.
[0030]
And the part which contacts the mixture S2 in the drum 41, ie, the drum inner peripheral surface 41a, the partition plate 42, the fixed blade 48, the stirring plate 52, and the surface of the stirring blade 53, are mixed with pulverized coal c and oil droplets a. A ceramic lining (not shown) such as alumina is applied in order to efficiently apply a shearing force at the time of contact and to prevent wear due to contact with the pulverized coal c.
[0031]
The stirring plate 52 is preferably operated in the range of 2G to 40G, more preferably 20G to 30G. Here, G is a centrifugal force determined by the stirring blade diameter and the rotational speed.
[0032]
As shown in FIG. 1, so-called coal slurry S <b> 1 in which pulverized coal and water are mixed to form a slurry is once introduced into a slurry adjustment tank 21, and is adjusted by a provided stirrer 31.
[0033]
The coal slurry S <b> 1 in the slurry adjustment tank 21 is supplied to the pulverized coal surface reformer 25 by the slurry pump 22. At that time, the collection agent A in the collection agent tank 27 is sent out by the fixed supply pump 28 and supplied to the coal slurry S <b> 1 passing through the pipe 32. Thereafter, the foaming agent B in the foaming agent tank 29 is quantitatively supplied by the constant supply pump 30 into the coal slurry S2 in which the collecting agent A is mixed. This state is a state shown in FIG. 6A, in which the pulverized coal c, the ash d, the oil droplet a of the collecting agent, and the droplet b of the foaming agent are mixed. W is water.
[0034]
As the scavenger A, mineral oils such as kerosene and light oil can be mainly used. Although it depends on the quality of the coal, the surface of the pulverized coal is improved by adding a very small amount of the trapping agent A of 0.01% to 1.0%, preferably 0.05% to 0.3% by weight with respect to the amount of pulverized coal. The machine 25 can form pulverized coal floss.
[0035]
On the other hand, the foaming agent B is for foaming the modified coal slurry, and pine oil, terpineol, polyoxypropylene alkyl ether, higher alcohol and the like can be used. Moreover, the addition amount is 50-1000 ppm with respect to the amount of pulverized coal, More preferably, 100-200 ppm is added.
[0036]
Then, the mixture S3 in which the coal slurry S1, the collecting agent A, and the foaming agent B are mixed is rapidly stirred by the pulverized coal surface reformer 25. That is, agitation energy 10 kW / ^{m 3} or more, ^preferably, agitation such that 25kW / ^{m 3} ~100kW / m 3 is performed.
[0037]
As shown in FIG. 5, when the mixture S3 is supplied into the drum 41 from the inlet 44, the mixture S3 of the coal slurry S1, the floating oil A, and the foaming agent B is rotated at a high speed by the stirring blade 53 that rotates at high speed. Stir. By this high-speed stirring, the mixture S3 passes through the flow passage 43, the gap between the stirring plate 52 and the cylindrical wall surface 41a and the like while being rapidly stirred by the stirring blade 53 that rotates together with the rotating shaft 51. 50, and becomes a modified coal slurry S4 and discharged from the outlet 45.
[0038]
More specifically, when the mixture S3 is supplied from the inlet 44 into the strong stirring zone M of the drum 41, the pulverized coal c and the oil droplets a are highly dispersed, and the pulverized coal c and the oil droplets a are dispersed. The cylindrical wall surface 41a, the partition plate 42, the fixed blade 43, the stirring plate 52, the stirring blade 53, and the like are brought into contact with each other. By this contact, a strong shearing force is applied to the pulverized coal c and the oil droplets a, and a very thin oil film a is spread on the surface of the pulverized coal c (see FIG. 6B). The oil film a improves and improves the wettability of the surface of the pulverized coal c, and enhances the lipophilicity of the surface of the pulverized coal c. As a result, the flotation performance is dramatically improved.
[0039]
The application of shearing force (sharing) is rapid agitation unlike conditioning, and therefore a shearing force is applied to the pulverized coal particles c and the oil droplets a to induce a shearing surface. At the moment when the shear surface is generated, it is considered that the oil droplets a are likely to adhere to and adhere to the particles c of the pulverized coal because the surface energy is instantaneously transiently exhibited.
[0040]
According to the structure of the pulverized coal surface reformer 25, since the partition plates 42 and the stirring plates 52 are alternately arranged, this configuration can prevent a short path from the inlet 44 to the outlet 45, which is efficient. A shearing force can be applied by mixing and contacting. By applying a shearing force by this mixing and contact, the oil droplets a can be efficiently attached to the surface of the pulverized coal c. Therefore, the surface of the pulverized coal c can be modified with a small amount of the collecting agent A in a short time.
[0041]
Then, the pulverized coal c modified by the pulverized coal surface reformer 25 is, as shown in FIG. 6 (c), the bubbles e obtained by foaming the foaming agent B while the oil film a is adhered. Adhere to the surface. In the centrifugal separation zone N on the downstream side of the strong stirring zone M, the object to be treated is stirred at high speed by the stirring blade 53, so that foaming of the foaming agent B is actively performed and fine powder adhering to the air bubbles e While the amount of coal increases, the ash d having a specific gravity larger than that of the pulverized coal c moves to the inner cylinder wall surface 4a side of the drum 1 due to the action of centrifugal force, and the separation from the pulverized coal c progresses as it moves downstream. To do. The pulverized coal c adhering to the bubbles e is sent to the floating sorter 26 together with a small amount of ash d.
[0042]
As described above, the low ash pulverized coal c to which the oil film a has adhered becomes attached to the bubbles e and floats on the water surface, so that the portion exceeding the weir 33 in the floating sorter 26 is recovered as the levitation component. Further, the pulverized coal c that has floated is separated by a vacuum filter or the like (not shown) and recovered as pulverized coal C.
[0043]
One ash d is more hydrophilic than pulverized coal c, and thus settles without being floated and separated as sludge D. This sludge D is sent to a thickener (not shown), separated from water, and discarded or reused as a raw material for “low-grade coal-water slurry”. On the other hand, the water from which the sludge D is separated is reused as circulating water.
[0044]
Therefore, according to this pulverized coal recovery method and apparatus, the pulverized coal surface reformer 25 modifies the mixture S2 of the coal slurry S1 and the scavenger A to thereby improve the flotation refined coal recovery rate and flotation. The floating speed can be greatly improved. Moreover, since the solid content in the wastewater can be reduced by improving the recovery rate, the drainage load can be reduced.
[0045]
In addition, the pulverized coal recovery method and apparatus according to the present invention can handle a wide range of slurry concentrations from concentrated flotation to direct flotation, and furthermore, it has been difficult to recover fine coal by the flotation method until now. Even for coal with poor selectivity, flotation can be applied by improving flotation by this surface modification method, and pulverized coal can be efficiently recovered by flotation. .
[0046]
In the above description, the case where the foaming agent B is added to the coal slurry S1 after the collection agent A is added to the coal slurry S1 has been described. However, as shown in FIG. It is also possible to connect the pipe 55 of the B to the pipe 56 of the collecting agent A and simultaneously add the collecting agent A and the foaming agent B to the coal slurry S1.
[0047]
【The invention's effect】
As described above, according to the present invention, the following effects can be achieved.
[0048]
That is, since the flotation property of pulverized coal can be greatly improved by the shearing action (sharing action) of the strong stirring zone of the pulverized coal surface reformer, a high coal recovery rate can be realized.
[0049]
In addition, a strong agitation zone (sharing process) of the pulverized coal surface reformer allows a thin oil film to be efficiently attached to the surface of the coal, so the amount of oil used is less than that of the conventional flotation method. A small amount. Moreover, since the flotation floatation speed has been greatly improved by the pulverized coal surface reformer, the flotation machine that has been conventionally required is no longer required.
[0050]
In addition, the pulverized coal recovery method of the present invention prevents the pulverized coal and flotation oil from floating on the surface of the thickener and lowers the drainage load. The wastewater treatment system can be operated smoothly throughout. In other words, the drainage system load is reduced by achieving good flotation performance, and smooth factory operation and reduction of environmental load can be achieved.
[0051]
Moreover, according to the pulverized coal recovery apparatus of the present invention, the coal slurry and the mixture of the flotation oil can be stirred at high speed, and shear force can be applied to the pulverized coal to improve the flotation property of the pulverized coal. . Moreover, the pulverized coal can be modified very efficiently by the configuration of the plurality of partition plates and the plurality of stirring plates. As a result, the device is very compact and requires less installation space. Therefore, even the existing pulverized coal flotation system can be easily incorporated in the previous stage of the flotation process.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a pulverized coal recovery apparatus according to the present invention.
FIG. 2 is a sectional view of a pulverized coal surface reformer.
FIG. 3 is a view taken along the line XX ′ of FIG.
4 is a view taken along arrow YY ′ of FIG. 2;
FIG. 5 is an operation explanatory view of a pulverized coal surface reformer.
6A is a diagram showing a mixed state of pulverized coal and the like, FIG. 6B is a diagram showing a surface modified state of the pulverized coal, and FIG. 6C is a diagram showing surface modified pulverized coal adhering to air bubbles.
FIG. 7 is an explanatory view of a conventional pulverized coal recovery method.
[Explanation of symbols]
A Collecting agent B Foaming agent b Foaming agent bubble c Pulverized coal S1 Coal slurry containing pulverized coal

Claims (9)

In the pulverized coal recovery method for recovering pulverized coal from coal slurry containing pulverized coal, a step of adding a collection agent and a foaming agent to the coal slurry, and a coal slurry containing the collection agent and the foaming agent And a pulverized coal whose surface has been modified by the sharing process at the same time that the foaming agent is foamed. A method for recovering pulverized coal, which is constituted by a floating sorting step in which bubbles of a foaming agent are floated. The method for recovering pulverized coal according to claim 1, wherein the collecting agent and the foaming agent are simultaneously added to the coal slurry. The method for recovering pulverized coal according to claim 1, wherein a collecting agent is added to the coal slurry, and then a foaming agent is added to the coal slurry. The method for recovering pulverized coal according to claim 1, 2 or 3, wherein the collecting agent is added in an amount of 0.01 to 1.0% by weight based on the amount of pulverized coal. The method for recovering pulverized coal according to claim 1, 2 or 3, wherein the foaming agent is added in an amount of 50 to 1000 ppm based on the amount of pulverized coal. In a pulverized coal recovery apparatus that recovers pulverized coal from coal slurry containing pulverized coal, means for adding a collection agent and a foaming agent to the coal slurry, and a coal slurry containing the collection agent and the foaming agent Is rapidly stirred to apply shear force to the pulverized coal and the oil droplets of the scavenger, and at the same time, the pulverized coal surface reformer for foaming the foaming agent, and the surface is modified by the pulverized coal surface reformer An apparatus for recovering pulverized coal, comprising a floating sorting tank for levitating the pulverized coal made by using bubbles of a foaming agent. The pulverized coal surface reformer has a doughnut-shaped partition plate in multiple stages in the longitudinal direction of the drum in a cylindrical drum, and rapidly stirs the coal slurry in the stirring chamber surrounded by the partition plate. An apparatus for recovering pulverized coal according to claim 6, wherein a stirring plate with stirring blades is provided, and a fixed blade is provided on a wall surface of the partition plate in the strong stirring zone upstream of the drum among the partition plates. The apparatus for recovering pulverized coal according to claim 6, comprising means for simultaneously adding a scavenger and a foaming agent to the coal slurry. The collection | recovery of pulverized coal of Claim 6 provided with the collection agent addition means which adds a collection agent to coal slurry, and the foaming agent addition means which adds a foaming agent to the coal slurry in which the collection agent was mixed. apparatus.

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