JP2018168247A - Method of producing molded coal article - Google Patents

Abstract

To produce a molded article of stable quality in a method of producing a molded coal article employing a vertical feed/discharge type molding machine.SOLUTION: Coal particles or a raw material used in producing a molded article employing a vertical feed/discharge type molding machine satisfy both of the following conditions: a≤0.29 and 20≤1/b≤60 in the formula (1): N/C=(1/ab)+(1/a)N, provided that Vo is an initial volume thereof per unit weight, Vis a volume thereof subsequent to performing tapping N-times, and C=(Vo-V)/Vo is the volume reduction ratio thereof.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a coal molded body that is formed after pulverizing coal.

  Conventionally, as a technique for obtaining a coal molded body, in Patent Document 1, after obtaining a first molded body by molding pulverized coal, the first molded body is crushed and molded again as a second molded body. A method for obtaining coal fuel having the desired strength is described. According to Patent Document 1, for molding the first molded body and the second molded body, a pair of rolls having pockets as molds of the molded body formed on the surface, and a screw for supplying a raw material between the pair of rolls, A molding machine (briquette machine) having the following is preferably used. On at least one surface of the pair of rolls, a pocket serving as a mold of a molded body is formed, and the raw material supplied between the rolls by the screw is filled in the pocket and pressurized in the pocket, thereby A molded body is obtained.

International Publication No. 2015/098935

  As a molding machine, a vertical supply / discharge molding machine is generally used in which raw materials are supplied from vertically above and a molded body is discharged vertically downward. When high-pressure molding of powdery raw material is performed with a vertical feed / discharge type molding machine, air is entrained in the raw material due to stirring of the screw, and the raw material floats. It sometimes became unstable.

  An object of this invention is to provide the manufacturing method of a coal molding which manufactures a molding with the stable quality in the manufacturing method of the coal molding using the vertical supply / discharge type molding machine.

The method for producing a coal molding according to the present invention is a coal molding that is molded by a vertical supply / discharge molding machine that molds coal particles supplied from vertically above and discharges the molded coal molding vertically downward. A method for manufacturing a body,
When the initial volume per unit weight is Vo, the volume at the time of tapping N times is V _N , and the degree of bulk reduction is C = (Vo−V _N ) / Vo,
Formula (1): N / C = (1 / ab) + (1 / a) N
In
Condition (1): a ≦ 0.29
Condition (2): 20 ≦ 1 / b ≦ 60
Is satisfied.

  According to the present invention, a coal molding can be manufactured with stable quality.

It is a figure which shows the manufacturing process of the coal molding by one Embodiment of this invention. It is a schematic diagram of the briquette machine which can be used suitably at a formation process. It is a top view of an example of the roll pocket formed in the roll surface of a briquette machine. It is a figure which shows the cross-sectional shape of the roll pocket shown to FIG. 3A. It is a figure which shows an example of the arrangement pattern of the groove | channel formed in the roll surface of a briquette machine.

  Referring to FIG. 1, a process for producing a coal molding according to an embodiment of the present invention is shown. In this embodiment, the manufacturing process of the coal molding includes a first crushing process 10, a drying process 20, a pulverizing process 30, a first molding process 40, a second crushing process 50, a second molding process 60, and a sieving process 70. ing. The coal 1 that is a raw material is crushed in the first crushing step 10 to be crushed material 2, then dried in the drying step 20 to be dried material 3, and the dried material 3 is further pulverized in the pulverizing step 30. Charcoal 4 is obtained. The pulverized coal 4 is molded as the first molded body 5 in the first molding step 40, and then crushed again in the second crushing step 50, whereby the second crushed matter 6 that is a lump corresponding to the coal particles is obtained. can get. Since the obtained lump is obtained by crushing the first molded body 5 obtained by molding the pulverized coal 4, it can be referred to as an aggregate of the pulverized coal 4. Thereafter, in the second molding step 60, the second molded body 7 is obtained from the second crushed material 6, and further, the powder is removed from the second molded body 7 by the sieving step 70, whereby the coal molded body 100 is obtained. The obtained coal molding 100 can be used suitably as a coal molding fuel.

  Note that the sieving step 70 is not an essential step in the present invention, and the second molded body 7 obtained in the second molding step 60 can be used as the coal molded body 100.

  As coal 1 used as a raw material, lignite or subbituminous coal having a water content of 25 wt% or more can be used. Preferably, lignite with a water content of 30 wt% or more can be used. In a series of manufacturing steps of a coal molding, only coal is used as a raw material, and additives such as a binder are not used. Use of an additive such as a binder increases the cost. However, in this embodiment, since only coal is used without adding a binder, a molded coal can be obtained at low cost.

  In the 1st crushing process 10, this coal 1 is crushed using appropriate crushing means, such as a jaw crusher or a hammer crusher, and the 1st crushed material 2 which is crushed coal is obtained. In the 1st crushing process 10, although coal should just be crushed to the magnitude | size which can be thrown into grinding | pulverization means, such as a ball mill used by the subsequent crushing process 30, it does not specifically limit, The magnitude | size of the 1st crushing thing 2 is the maximum particle diameter. However, it is preferably 70 mm or less, more preferably 50 mm or less, still more preferably 20 mm or less, and particularly preferably the average particle diameter is 1 mm to 20 mm or less. Here, the average particle diameter of the coal crushed by the first crushing step 10 is measured based on “5. Particle size test method” of JIS M 8801-4, and the passing sieve mass percentage of each sieve opening is obtained. The particle diameter at which the passing sieve mass percentage is 50% is defined as the average particle diameter.

  The obtained first crushed material 2 is supplied to the drying step 20. In the drying step 20, the first crushed material 2 is dried using an appropriate dryer such as an indirect dryer to obtain a dried product 3. As the indirect dryer, for example, a steam tube dryer can be used. In the production of solid fuel in which the coal molded body 100 is preferably used, a large amount of processing is required. Therefore, the steam tube dryer having a large heat transfer area and capable of a large amount of drying processing is suitable as a dryer used in the drying step 20. is there.

  The obtained dried product 3 is supplied to the pulverizing step 30. In the pulverization step 30, the dried product 3 is pulverized by an appropriate pulverizer to obtain pulverized coal 4. As the pulverizer, a dry pulverizer or a dry pulverizer pulverizer can be used. Among them, a ball mill or a roller mill that can be finely pulverized and is suitable for mass processing can be preferably used. This is because, in the production of solid fuel, a large amount of processing is required in the pulverization step 30 as in the drying step 20.

  The average particle diameter of the pulverized coal 4 obtained in the pulverization step 30 is 10 to 60 μm, preferably 10 to 50 μm, more preferably 10 to 30 μm. The average particle diameter of the pulverized coal 4 is given by the median diameter of the particle size distribution obtained by the laser diffraction / scattering method. In the present specification, “pulverized coal” means the pulverized coal 4 obtained in the pulverization step 30.

  By setting the average particle diameter of the pulverized coal 4 obtained in the pulverization step 30 within the above range, the filling rate of the mold (for example, roll pocket) is increased when the fine pulverized coal 4 is molded in the first molding step 40. And the desired intensity | strength can be obtained by improving the density of the coal molding 100 mentioned later.

  Since the ball mill and the roller mill can be dried simultaneously with the pulverization, the ball mill and the roller mill can also be dried by the ball mill or the roller mill in the pulverization step 30. However, since it is difficult to sufficiently dry the crushed material 2 obtained in the first crushing step 10 with the drying ability in the ball mill and the roller mill, in this embodiment, the drying step 20 is provided before the crushing step 30. Thus, a sufficiently dry pulverized coal 4 is obtained.

  The obtained pulverized coal 4 is supplied to the first molding step 40. The first molding step 40 includes molding the pulverized coal 4 into a plate shape using a molding machine. The molding machine has a molding means for pressure-molding the raw material (in this embodiment, pulverized coal 4) and a supply means for supplying the raw material to the molding means. As such a molding machine, for example, a briquette machine can be used.

  FIG. 2 shows a schematic diagram of a briquette machine that can be suitably used in the first molding step 40. The briquette machine shown in FIG. 2 is a vertical supply / discharge briquette machine that molds the pulverized coal 4 supplied from vertically above and discharges the molded first molded body 5 to the vertically lower side. The briquette machine has a pair of rolls 41 that are molding means, and a supply means 42 that is disposed above the pair of rolls 41 and supplies pulverized coal 4 that is a raw material between the pair of rolls 41. The supply means 42 includes a hopper to which the pulverized coal 4 is supplied, a screw feeder that sends the pulverized coal 4 in the hopper downward, and the like. Each of the pair of rolls 41 has a rotation shaft that is driven by appropriate driving means. The rotating shaft extends in the horizontal direction, and the pair of rolls 41 are arranged in parallel to each other with a gap in the horizontal direction. The pulverized coal 4 supplied from above into the gap of the roll 41 is sent downward while being pressurized by the rotational drive of the roll 41, whereby the first molded body 5 in which the pulverized coal 4 is pressure-molded is obtained.

  If the gap (clearance) between the pair of rolls 41 is too wide, leakage of the pulverized coal 4 from the rolls 41 and pressure dispersion are likely to occur, and the density and strength of the first molded body 5 to be obtained are reduced. This leads to a decrease in rate. Therefore, the gap between the rolls 41 is preferably 3 mm or less. By setting the gap between the rolls 41 to 3 mm or less, it is possible to obtain the plate-like first molded body 5 in which sufficient strength is ensured.

  Further, it is preferable that irregularities are formed on the surface of at least one of the pair of rolls 41. Thereby, it is suppressed that the pulverized coal 4 supplied between the rollers 41 slides down from the surface of the roller 41, and the pulverized coal 4 can be favorably held between the rollers 41 and pressurized. Moreover, since the pulverized coal 4 is filled in the recesses by forming the irregularities, the processing amount per unit time can be increased. When the surface of the roll 41 has irregularities, the irregularities on the surface of the roll 41 are transferred to the surface shape of the obtained first molded body 5.

  The form of the unevenness formed on the surface of the roll 41 is not particularly limited, and may be, for example, a roll pocket (concave portion), a groove, or a combination thereof.

  When the irregularities are formed by roll pockets, the shape of the roll pocket can be arbitrary. An example of the shape of the roll pocket is shown in FIGS. 3A and 3B. The illustrated example is an example in which a substantially elliptical roll pocket is formed only on one side of the roll, whereby a first molded body 5 having a convex part of a one-sided plane almond shape is obtained. The roll pocket may be formed on the rolls on both sides, and the planar shape of the roll pocket may be a rounded polygon, a circle, or an oval. The dimensions (vertical length a, horizontal length b, depth c) of each part of the roll pocket, and the gap d between the rolls 41 (thickness formed at the surface portion of the first molded body 5 where the irregularities are not formed. Table 1 shows the preferred dimension range of

  Further, when the unevenness is formed by grooves, the width, depth, arrangement, etc. of the grooves can be arbitrary. For example, as shown in FIG. 4, a plurality of grooves parallel to the axial direction A of the roll 41 and a plurality of grooves parallel to the circumferential direction B may be arranged in a lattice pattern. In addition to this, a plurality of grooves parallel to the axial direction A of the roll 41 and a plurality of grooves oblique to the axial direction A and the circumferential direction B of the roll 41 are arranged to intersect. Etc. are also possible. The width of the groove (the length in the direction perpendicular to the length direction of the groove on the surface of the roll 41) is preferably 0.5 to 5 mm. The depth of the groove is preferably 0.5 to 2 mm.

The first molded body 5 obtained in the first molding step 40, it is preferable that an apparent density of ^{1.00g / cm 3 ~1.25g / cm 3} , it is preferred crush strength is 10～800N. Moreover, it is preferable that the total water | moisture content of the pulverized coal 4 used at the 1st shaping | molding process 40 is 5-20 wt%, It is more preferable that it is 8-18 wt%, It is further more preferable that it is 10-17 wt%.

  In the first molding step 40, a horizontal supply / discharge molding machine, for example, a compactor, which supplies raw materials in the horizontal direction and discharges the molded first molded body 5 in the horizontal direction can be used. Similarly to the vertical supply / discharge type briquette machine, the horizontal supply / discharge type compactor also has a forming means for forming the raw material and a supply means for supplying the raw material to the forming means. The molding means can have, for example, a pair of rolls, and the pair of rolls are arranged so that the raw material is pressure-molded between the rolls as the roll rotates as the raw material is supplied between the rolls. Is done. However, in a horizontal supply / discharge compactor, two rolls are arranged up and down. By using a horizontal supply and discharge type compactor in the first molding step 40, the yield of the first molded body 5 obtained, that is, the molding efficiency can be improved.

  The first molded body 5 obtained in the first molding step 40 is supplied to the second crushing step 50. In the 2nd crushing process 50, the 1st molded object 5 is crushed with a crusher, and the 2nd crushing thing 6 which is a lump is obtained. The second crushed material 6 is an aggregate of pulverized coal, and this pulverized coal corresponds to the pulverized coal 4 obtained in the pulverization step 30. Therefore, the pulverized coal preferably has an average particle size of 10 to 60 μm, and preferably has a total water content of 5 to 20 wt%.

  The crusher used in the second crushing step 50 may be the same as that used in the crushing step 20. The second crushed material 6 preferably has an average particle diameter of 0.1 to 1.0 mm, more preferably 0.15 to 0.9 mm, and still more preferably 0.2 to 0.8 mm. Moreover, it is preferable that the maximum particle diameter of the 2nd crushing material 6 is below the length of the shorter one among the two sides of the vertical and horizontal sides of the particle diameter of the below-mentioned 2nd molded object 7. By adjusting the second crushing step 50 so that the second crushed material 6 is in the above average particle size range and the maximum particle size range, the second crushing product 6 is molded into the mold in the molding machine at the time of molding in the second molding step 50. The filling rate of the crushed material 6 can be improved. As a result, the resulting second molded body 7 has superior quality (crushing strength and apparent density) as compared to the first molded body 5. In addition, when using a briquette machine as a molding machine in the 1st shaping | molding process 40 and the 2nd shaping | molding process 60, the size (particle diameter) of the roll pocket formed in a roll surface is the 1st shaping | molding process 40 and the 2nd shaping | molding process 60. May or may not be the same.

  In the second molding step 60, the second crushed material 6 is molded by a molding machine to obtain the second molded body 7, but the second molded body 7 falls from between the rolls without being pressure-molded between the rolls. The 2nd crushed material 6 and the 2nd crushed material 6 which fell out from the 2nd molded object 7 without fully press-molding may also be included. These second crushed materials 6 are preferably removed by a sieving step 70 provided after the second molding step 60, whereby the coal molded body 100 is obtained. In the sieving step 70, a vibration sieving machine can be used. As the vibrating sieve, a circular sieve, a trommel sieve, or the like can be used, and among them, those capable of continuous / mass processing are preferable.

  As the molding machine used in the second molding process 60, a vertical supply / discharge molding machine, such as a briquette machine, can be used as in the first molding process 40.

  In general, in a vertical supply / discharge molding machine having a screw-type supply means, air is entrained in the second crushed material 6 by agitation of the second crushed material 6 as a raw material by a screw. The amount of air entrained in the second crushed material 6 tends to increase as the screw rotation speed increases. When the second crushed material 6 accompanied with air is supplied between the rolls, air is pushed out from the second crushed material 6 as the second crushed material 6 is compressed by the roll. Although the pushed air flows upward, the supply direction of the second crushed material 6 is downward, so that a phenomenon such as flushing of the second crushed material 6 occurs when the amount of air generated is large. Thereby, the continuous supply of the raw material between the rolls is not sufficiently performed, and the second molded body 7 has a stable quality (crushing strength and apparent density) such that the second molded body 7 is intermittently discharged. It becomes difficult to be molded.

To avoid this,
(I) increase the density of the second crushed material 6 itself (to increase the weight), and (ii) increase the filling rate of the second crushed material 6 between the rolls,
And so on. However, in the case of (i), if the density of the second crushed material 6 itself is too high, the quality of the obtained second molded body 7 is affected. In the case of (ii), there is a method of increasing the filling rate by reducing the particle size of the second crushed material 6, but by reducing the particle size of the second crushed material 6, the second crushed material 6 Flushing is likely to occur, which may be counterproductive.

Therefore, as a result of repeated studies by the present inventors, it was found that when the fluidity of the raw material was expressed by a specific index, the index correlated with the stable operation of the vertical supply / discharge molding machine. That is, when the initial volume per unit weight of the second crushed material 6 is Vo, the volume after N times tapping is V _N, and the degree of bulk reduction after tapping is C = (Vo−V _N ) / Vo,
Formula (1): N / C = (1 / ab) + (1 / a) N
In
Condition (1): a ≦ 0.29
Condition (2): 20 ≦ 1 / b ≦ 60
Is to satisfy both. By adjusting the characteristics of the raw material supplied to the vertical supply / discharge molding machine so as to satisfy these conditions (1) and (2), the instability of the raw material due to the air flow generated in the molding by the molding machine Therefore, efficient molding can be performed with stable operation of the molding machine.

  The above equation (1) is called Kawakita's equation and is known to accurately indicate the compression / flow characteristics of the powder. In Kawakita's equation, “a” is a liquidity index, and the smaller this value, the better the liquidity. “1 / b” is an adhesion index, and the smaller the value, the weaker the adhesion.

  Here, in the present invention, whether or not the molding machine is stably operated is determined as follows.

  The state in which the operation is stable refers to a situation where a certain amount of raw material is molded as a molded body having a certain quality. The quality (crushing strength, apparent density) of the molded product discharged from the molding machine depends on the roll kW that is the output of the drive motor that rotates the roll. If the roll kW can be maintained constant, the molded product of a constant quality Is discharged. Therefore, if the roll kW is kept constant at a constant roll speed, it is determined that the molding machine is stably operated. When the roll kW is low, the quality of the molded body is deteriorated, or the ratio of raw materials left unmolded due to insufficient compression force is increased. Here, “the roll rotation speed and the roll kW are“ constant ”” means that these fluctuations are within a range of ± 15% with respect to the reference value (set value).

  In actual operation, the physical properties (particle size distribution, apparent density, strength, etc.) and bulk density of the supplied raw material may vary. This is because the coal 1 that is the raw material supplied to the molding machine is a natural product, and therefore physical properties such as particle size distribution, apparent density, and strength vary depending on the mining site. Variations in the physical properties of the raw material cause variations in the roll kW of the molding machine. Moreover, the fluctuation | variation of the bulk density of the raw material supplied to a molding machine also becomes a factor of fluctuation | variation of the roll kW. In this case, the roll kW can be kept constant by controlling the screw rotation speed and adjusting the supply amount of the raw material between the rolls. Even if there is a change in the physical properties of the raw material to be supplied, if a constant roll kW can be maintained. It can be said that a certain amount of molded product of a certain quality is discharged, and as a result, the operation is stable.

  Depending on the physical properties of the raw material, the roll kW may not be maintained constant even if the screw rotation speed is controlled. In this case, it is determined that the operation of the molding machine is unstable.

The particle diameter of the second molded body 7 obtained in the second molding step 60 is preferably 5 to 40 mm. The second molded body 7 preferably has an apparent density of 1.2 to 1.4 g / cm ³ and a bulk density of 0.4 to 0.6. The weight of the second molded body 7 is preferably 0.2-20. The total moisture of the second molded body 7 is 5 to 20 wt%, preferably 8 to 18 wt%, and more preferably 10 to 17 wt%. The moisture of the coal molded body 100 is derived from the moisture of the second crushed material 6 that is a raw material in the second molding step 60.

Here, the apparent density is a value measured based on “8. Method for measuring density and specific gravity by submerged weighing method” of JIS Z 8807. The bulk density is a value calculated by the following formula from the weight of the filled sample and the volume of the container after the sample is ground and filled in a container of about 2 to 5 L whose volume is known. In addition, the method of throwing into the container differs between rough filling and dense filling. In the rough filling, when the sample was put into the container, the sample was filled so as not to be compacted as much as possible, and in the close filling, the container was filled while tapping. The number of tapping was 10 times.
Bulk density = Mass of filled sample ÷ Container volume

  The water content is a value measured based on “Measurement method of total water content of coals” of JIS M 8820-0. Moreover, it is preferable that the coal molding 100 has a hard glove grindability index (HGI) of 40 or more.

  As described above, in the present embodiment, the first molded body 5 once molded is crushed again in the second crushing step 50 and molded again in the second molding step 60. The first molded body 5 is in a state in which the density has already been increased to some extent in the first molding step 40, and the second crushed material 6 also has a similar density. Therefore, by molding the second crushed material 6 again, it is possible to obtain the second molded body 7 having a further improved density than the first molded body 5.

  Moreover, the average particle diameter of the pulverized coal 4 pulverized in the pulverization step 30 is 10 to 60 μm, and as it is, the fluidity in the briquette machine is poor and it may be difficult to mold. On the other hand, if the crushed material of the first molded body 5 once molded, the density is increased to some extent by the first molding step 40, so that the fluidity in the briquette machine is improved and the second molding step 60 Molding is performed smoothly. Thereby, the 2nd molded object 7 whose density is higher than the 1st molded object 5 will be obtained, and by making this 2nd molded object 7 into the coal molded object 100, the powdering at the time of storage and conveyance is carried out. Furthermore, it is reduced, handling property can be improved, and it becomes suitable as a coal molding fuel.

  In addition, you may provide the water | moisture-content adjustment process of adjusting the total water | moisture content of the coal molding 100 finally obtained. In the case where the moisture adjusting step has the sieving step 70, the moisture adjusting step is preferably provided after the sieving step 70. By the moisture adjustment step, dust generation and spontaneous heat generation of the coal molded body 100 can be prevented.

  In the moisture adjustment step, a belt conveyor is arranged, and a watering facility including a water supply pump and a spray nozzle is arranged on the belt conveyor, and the coal molding 100 is conveyed by the belt conveyor. There is a method in which the moisture of the coal molded body 100 falls within a suitable range with respect to the coal molded body 100 that has passed through the sieving process 70. Further, after the coal molding 100 that has undergone the sieving process 70 is erected (stacked in a mountain shape to form a pile), the water of the erected coal molded body 100 is preferably used by a watering facility including a water supply pump and a sprinkler. A method of adjusting the range may be used.

  The moisture after the moisture adjustment step of the coal molded body 100 is preferably 10 to 30 wt%, more preferably 10 wt% or more and less than 25 wt%.

  The quality evaluation of the obtained coal molding was performed by Examples 1-3 and Comparative Example 1. In these Examples 1 to 3 and Comparative Example 1, as shown in FIG. 1, the first crushing process 10, the drying process 20, the crushing process 30, the first molding process 40, the second crushing process 50, and the second molding process 60. And the coal molding 100 is obtained through the sieving process 70. Tables 2 and 3 show the properties of the coal used in Examples 1 to 3 and Comparative Example 1.

Example 1
In this example, Indonesian lignite B coal was crushed in the first crushing step 10 using a hammer crusher so that the average particle size would be 3 mm or less. Next, the crushed B charcoal was dried in a drying step 20 using a steam tube dryer so that the total moisture of the dried product 3 was 11.2%. In the subsequent pulverization step 30, the dried B charcoal was pulverized using a roller mill so that the average particle diameter of the pulverized coal 4 was 19 μm. Next, the pulverized coal 4 obtained by the pulverization step 30 was molded in the first molding step 40.

  In the first molding step 40, a vertical supply / discharge briquette machine was used as a molding machine. The briquette machine used has a pair of rolls 41 as shown in FIG. 2, in which only one of the rolls 41 has a roll pocket, and the other roll 41 has a flat outer peripheral surface without unevenness. Was. The pair of rolls 41 had a diameter of 520 mm and an axial length of 236 mm.

  The shape of the roll pocket was an almond shape having a substantially elliptical shape in plan view as shown in FIGS. 3A and 3B. On the roll 41, two types of roll pockets of shape A and shape B having different dimensions were formed. Table 4 shows the dimensions of the roll pocket.

On the peripheral surface of the roll 41, 5244 roll pockets of shape A and 184 roll pockets of form B were regularly distributed. Volume per one roll pockets, shape A is 0.035Cm ^3, shape B was 0.0048cm ^3. Further, if the gap between the rolls 41 is large, leakage of the pulverized coal 4 and pressure dispersion are likely to occur, so the gap d between the rolls 41 is set to 1 mm. Moreover, the briquette machine adjusted the rotation speed of the roll 41 and the screw so that the roll linear pressure was maintained at 1.9 t / cm.

The apparent density of the first molded body 5 obtained by the first molding step 40 was measured and found to be 1.077 g / cm ³ .

  After the 1st shaping | molding process 40, the obtained 1st molded object 5 was crushed in the 2nd crushing process 50, and the 2nd crushing thing 6 was obtained. In the second crushing step 50, a hammer crusher was used.

  Subsequently, the 2nd crushing thing 6 was shape | molded in the 2nd shaping | molding process 60, and the 2nd molded object 7 was obtained. In the second molding step 60, the same briquette machine as used in the first molding step 40 was used, and the rotation speeds of the roll 41 and the screw were adjusted so that the roll linear pressure was maintained at 7 t / cm.

  After the 2nd shaping | molding process 60, in the sieving process 70, the pulverized coal was removed from the 2nd shaping | molding body 7, and the coal molding 100 was obtained. In the sieving step 70, sieving was performed manually using a standard sieve having an opening of 3.35 mm. The proportion on the sieve was 93.9%. Thereby, it has confirmed that the 2nd shaping | molding process 60 was drive | operated stably and the coal molding 100 was obtained with high yield.

In addition, when the physical property of the 2nd crushing thing 6 obtained at the 2nd crushing process 50 was measured, an average particle diameter is 0.40 mm, bulk density (coarse) is 0.65 g / cm < ³ >, and bulk density (dense) is. It was 0.84 g / cm ³ .

Moreover, the tapping machine was used to measure the change in tap density until the second crushed material 6 was tapped 500 times. The tap density is an apparent bulk density when a sample (which is a powder) is gently filled in a container (measuring cylinder) and then tapped and tightly packed. Tapping was performed by moving the container upward and then dropping the container freely. The stroke of the tapping machine was 20 mm, and the tapping speed was 35 times / min. Record the volume of the sample (second crushed material 6) (from the scale of the graduated cylinder) at each of the 0, 5, 10, 25, 75, 100, 250, and 500 tapping times. And the tap density in each frequency | count was calculated | required from the preparation weight. This result was applied to the above-described formula (1), and the fluidity and adhesion as the powder of the second crushed material 6 were evaluated.
Formula (1): N / C = (1 / ab) + (1 / a) N

  The evaluation of fluidity was performed by the fluidity index a, and the evaluation of adhesion was performed by the adhesion index 1 / b. When these indices were determined from the tap density measurement results, the fluidity index a was 0.28 and the adhesion index 1 / b was 53.4.

(Example 2, Example 3, Comparative Example 1)
The coal molded body 100 was manufactured in the same procedure as in the first embodiment, with some parameters changed from those in the first embodiment. The changed parameters are the total moisture of the dried product 3, the average particle diameter of the pulverized coal 4, and the roll linear pressure of the first molding step 40. By changing these parameters, various evaluation results (the yield in the second molding step 60, the operational stability of the second molding step 60, the apparent density of the first molded body 5, and the average of the second crushed material 6) These results, in which the particle size, bulk density, fluidity index a and adhesion index 1 / b) were changed, are shown in Table 5 together with the results in Example 1.

(Discussion)
It has been found that changing the parameters affects the operational stability and yield in the second molding step. In particular, paying attention to the characteristics of the raw material (second crushed material) in the second molding step, when a briquette machine is used, the fluidity index a of the raw material (second crushed material) is 0.29 or less and adheres. When the property 1 / b satisfies 20 ≦ 1 / b ≦ 60, it can be said that the briquette machine can be stably operated at a high yield.

  As explained above, according to the form of this invention, the manufacturing method of the coal molding described in the following (1)-(3) is provided.

(1) A method for producing a coal molded body molded by a vertical supply / discharge molding machine that molds coal particles supplied from vertically above and discharges the molded coal molded body 100 vertically downward. ,
When the initial volume per unit weight is Vo, the volume at the time of tapping N times is V _N , and the degree of bulk reduction is C = (Vo−V _N ) / Vo,
Formula (1): N / C = (1 / ab) + (1 / a) N
In
Condition (1): a ≦ 0.29
Condition (2): 20 ≦ 1 / b ≦ 60
A method for producing a coal molding characterized by satisfying any of the above.

(2) In the method for producing a molded coal according to (1) above,
A first crushing step 10 for crushing the coal 1;
A drying step 20 for drying the coal crushed in the first crushing step 10;
Crushing the coal dried in the drying step 20 to obtain pulverized coal; and
A first molding step 40 for molding the pulverized coal to obtain a first molded body 5;
A second crushing step 50 for crushing the first molded body 5 to generate a lump,
A second molding step 60 for molding the mass again to generate a second molded body 7;
Have
The lump is an aggregate of the pulverized coal, corresponding to the coal particles,
In the second molding step 60, the vertical supply / discharge molding machine is applied,
A method for producing a coal molding characterized by the above.

(3) In the method for producing a molded coal according to (2) above,
The pulverized coal has an average particle size of 10 to 60 μm and a total water content of 5 to 20 wt%,
The apparent density of the second molded body 7 is 1.2 to 1.4 g / cm ³ ,
A method for producing a coal molding characterized by the above.

DESCRIPTION OF SYMBOLS 1 Coal 2 1st crushed material 3 Dry material 4 Ground material 5 1st molded object 6 2nd crushed material 7 2nd molded object 10 1st crushing process 20 Drying process 30 Crushing process 40 1st shaping | molding process 50 2nd crushing process 60 Second molding process 70 Sieving process 100 Molded body

Claims (3)

A method for producing a coal molded body molded by a vertical supply / discharge molding machine that molds coal particles supplied from vertically above and discharges the molded coal molded body vertically downward,
When the initial volume per unit weight is Vo, the volume at the time of tapping N times is V _N , and the degree of bulk reduction is C = (Vo−V _N ) / Vo,
Formula (1): N / C = (1 / ab) + (1 / a) N
In
Condition (1): a ≦ 0.29
Condition (2): 20 ≦ 1 / b ≦ 60
A method for producing a coal molding characterized by satisfying any of the above. In the manufacturing method of the coal molding of Claim 1,
A first crushing step of crushing coal;
A drying step of drying the coal crushed in the first crushing step;
Crushing the coal dried in the drying step to obtain pulverized coal;
A first molding step of molding the pulverized coal to obtain a first molded body;
A second crushing step of crushing the first molded body to generate a lump,
A second molding step for re-molding the mass and generating a second molded body;
Have
The lump is an aggregate of the pulverized coal, corresponding to the coal particles,
In the second molding step, the vertical supply / discharge molding machine is applied,
A method for producing a coal molding characterized by the above. In the manufacturing method of the coal molding of Claim 2,
The pulverized coal has an average particle size of 10 to 60 μm and a total water content of 5 to 20 wt%,
The apparent density of the second molded body is 1.2 to 1.4 g / cm ³ ,
A method for producing a coal molding characterized by the above.

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