JP2015030738A - Method for manufacturing modified coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing modified coal, capable of improving the productivity of coal having a less mercury content and a high calorific value.SOLUTION: A method for manufacturing modified coal comprises: the dry decalcification step S1 of dry decalcifying a low quality coal 1 used as coal to remove ashes 7 and obtain a decalcified coal 2; the drying step S2 of drying the decalcified coal 2 obtained by the dry decalcification S1 to obtain a dry decalcified coal 3; the fractionation step S3 of fractionating some of the dry decalcified coal 3 obtained by the drying step S2; the carbonization step S4 of carbonizing the dry decalcified coal 3a obtained by the drying step S2 to obtain a dry decalcified coal 4; and the mixing step S5 of mixing the dry decalcified coal 4 obtained by the carbonization step S4 and the dry decalcified coal 3b fractionated by the fractionation step S3 to obtain a decalcified mixture coal 5.

Description

  The present invention relates to a method for producing modified coal.

  Low-grade coal (low-quality coal) with a high water content such as lignite and sub-bituminous coal has a low calorific value per unit weight, so it is dried and dry-distilled by heating, and in a low-oxygen atmosphere. By modifying so as to reduce the surface activity, a modified coal having a higher calorific value per unit weight while preventing spontaneous ignition (see, for example, Patent Document 1 below).

  Further, it is known that mercury can be removed by a heating operation in dry distillation in a coal reforming process involving dry distillation as described above (see, for example, Patent Document 2 below).

JP 2011-37937 A US Pat. No. 5,403,365 US Pat. No. 8,394,240 US Pat. No. 7,540,384

R. Weinstein and R. Snoby, "Advances in dry jigging improves coal quality", p.29-p.34, Mining Engineering, January 2007 William H. Pollock et al., "Lowering Costs with Dry Coal Cleaning Technology to Meet New Environmental Requirements", p.1-p.13, Presented at the 10th Anniversary CoalGen Conference, Pittsburgh, PA, August 10, 2010

  However, the above-described coal reforming process has a drawback in that productivity is low because the yield of reformed coal, which is a product, is reduced by pyrolysis of coal by dry distillation.

  In addition, in the coal reforming process combined with dry deashing as shown in Patent Document 3 described above, it is difficult to recover light pyrolysis components in the dry distillation step, so the yield of reformed coal is reduced. As a result, there is a problem that productivity is lowered.

  For this reason, the present invention has been made to solve the above-described problems, and is a modification that can improve the productivity of coal with reduced mercury content and increased calorific value. It aims to provide a method for producing coal.

The method for producing modified coal according to the first invention for solving the above-described problem is as follows.
A dry deashing process for dry deashing coal to obtain deashed coal from which ash has been removed;
A drying step of drying the decalcified coal obtained in the dry deashing step to obtain deashed dry coal;
A fractionation step of fractionating a portion of the demineralized dry coal obtained in the drying step;
A carbonization step of carbonizing the demineralized dry coal obtained in the drying step to obtain demineralized dry coal;
The demineralized dry coal obtained in the dry distillation step and the deashed dry coal separated in the preparative step are mixed to obtain a demineralized mixed coal.

The method for producing a modified coal according to the second invention for solving the above-described problem is a method for producing the modified coal according to the first invention described above,
The drying step is performed using a dryer with a structure that dries the coal with a carrier gas and discharges the carrier gas.
The fractionation step is performed using the wind fan of the dryer.

The method for producing reformed coal according to the third invention for solving the above-described problem is a method for producing reformed coal according to the second invention described above,
The amount of the dry coal to be sorted in the sorting step is adjusted according to the flow rate of the carrier gas flowing to the wind tank.

The method for producing reformed coal according to the fourth invention for solving the above-mentioned problem is a method for producing reformed coal according to any one of the first to third inventions described above,
The dry deashing step includes a pulverizer that pulverizes the dry coal and the carbonized carbon, and a magnetic separation device that separates and removes the ash from the dry coal and the carbonized carbon pulverized by the pulverizer by magnetism. It is performed using.

The method for producing reformed coal according to the fifth invention for solving the above-described problem is a method for producing reformed coal according to any one of the first to third inventions described above,
The dry deashing step is performed using an airflow separation device that separates and removes the ash from the dry coal and the dry distillation coal using an airflow.

The method for producing reformed coal according to the sixth invention for solving the above-mentioned problem is a method for producing reformed coal according to any one of the first to fifth inventions described above,
The coal is low-grade coal.

  According to the method for producing modified coal according to the present invention, by deashing coal and removing ash from the coal, mercury in the coal can be physically removed together with the ash, By dry-distilling deashed and dry coal that has been dry deashed and dried, it is possible to chemically remove mercury in the deashed and dry coal along with volatile components, so the resulting deashed coal mixture contains mercury. The amount is reduced. Furthermore, deashed carbonized coal obtained by dry deashing, drying and dry distillation of coal, and mixed deashed dry coal are mixed to obtain deashed mixed coal, which increases the calorific value compared to coal. Can do. The obtained demineralized mixed charcoal contains deashed dry coal obtained by dry deashing, dried and dry-distilled, and deashed dry coal obtained by dry deashing, dried and fractionated, and dried. Compared to dry-distilled coal, the yield is higher. That is, it is possible to improve the productivity of demineralized mixed coal with a reduced mercury content and an increased calorific value.

It is a procedure flow figure of one embodiment of a manufacturing method of reformed coal concerning the present invention.

  One embodiment of a method for producing reformed coal according to the present invention will be described with reference to the drawings. However, the present invention is not limited to only the following embodiment described with reference to the drawings.

  One embodiment of a method for producing modified coal according to the present invention will be described with reference to FIG.

  As shown in FIG. 1, the method for producing reformed coal according to the present embodiment is a dry deashing step S <b> 1 in which low-grade coal (low quality coal) 1 is dry deashed to remove deashed coal 2 from which ash 7 is removed. The drying step S2 for drying the decalcified coal 2 obtained in the dry deashing step S1 to obtain the deashed dry coal 3 and a part of the deashing dry coal 3 obtained in the drying step S2 are fractionated. Preparative process S3, dry distillation process S4 which dry-distills dry coal 3a which has not been separated in preparative process S3 to obtain deashed dry distillation coal 4, demineralized dry distillation coal 4 obtained in dry distillation process S4 and fractionation The mixing step S5 for obtaining the deashed mixed coal 5 by mixing the dry coal 3b separated in the step S3 is performed.

  The low quality coal 1 is a coal having a high water content (60 to 70%) such as lignite and subbituminous coal, and has a large reserve, but has a low calorific value per unit weight and a poor transport efficiency. It is.

  The dry deashing step S1 is a step of separating and removing the ash 7 contained in the low quality coal 1 from the low quality coal 1, for example, a pulverizer for pulverizing the low quality coal 1 and the pulverizer. The low quality coal 1 pulverized by the above is supplied to a dry demineralizer equipped with a magnetic separator for separating and removing the ash 7 by magnetism, and pulverized to, for example, a particle size of 200 mesh or less, and ash 7 ( In particular, pyrite with a high mercury content is separated and removed by magnetism, and deashed coal 2 having an ash content of, for example, about 35% is manufactured. Alternatively, the dry-type deashing step S1 is supplied to a dry-type deashing device such as an air flow separation device, and flows on a fluidized bed and air is supplied to supply ash 7 (particularly to coal such as pyrite with a high mercury content). In comparison, heavy materials) are separated and removed, and deashed coal 2 having an ash content of, for example, about 35% is manufactured. That is, the dry demineralization step S1 produces demineralized coal 2 from the low quality coal 1 in which most of the mercury in the low quality coal 1 is physically removed together with the ash 7.

  As a dry deashing device including the pulverizer and the magnetic separation device, for example, a device described in Non-Patent Document 1 can be used. As a dry deashing device such as the airflow separation device, for example, devices described in Patent Document 4 and Non-Patent Document 2 can be used.

  The drying step S2 is a step of removing the water 8 from the demineralized charcoal 2. For example, the drying step S2 is supplied to a hot air dryer such as a belt conveyor type and dried with hot air (100 to 280 ° C. (preferably 150 to 200 ° C.). )), Demineralized dry charcoal 3 having a water content of approximately 0% is produced.

  The fractionation step S3 is a step of fractionating part of the demineralized dry coal 3, for example, dry coal supplied to a fractionation device such as a belt conveyor or a screw feeder and fed to the dry distillation step S4. 3a and dry charcoal 3b fed to the mixing step S5. The fraction to be collected can be adjusted according to the target oxygen content and mercury content in the deashed mixed coal 5. This is because the oxygen content and mercury content of the decalcified carbonized coal 4, deashed dry coal 3 b and deashed mixed coal 5 are adjusted according to the respective processing conditions, and can also be obtained by analysis. Because. In addition, the sorting step S3 can be performed using the wind kite with the structure of the portion where the carrier gas used in the dryer of the drying step S2 is discharged from the dryer as a wind kite. In this case, the amount of the deashed and dried charcoal 3b sorted in the sorting step S3 is adjusted by the flow rate of the carrier gas. For example, when the flow rate of the carrier gas is increased, it is possible to increase the proportion of the decalcified dry charcoal 3b that is separated along with the carrier gas.

  The carbonization step S4 is a step of removing volatile components 9 such as tar from the demineralized dry coal 3a. For example, the demineralized dry coal 3a is supplied to a continuous type carbonizer and is heated to a high temperature (300 to 500 ° C). (Preferably 400 to 450 ° C.), and the mercury contained in the demineralized dry coal 3a is separated and recovered together with the volatile component 9 such as tar to produce the demineralized carbonized coal 4. That is, in the carbonization step S4, the demineralized dry coal 4a obtained by chemically removing mercury in the demineralized dry coal 3a together with the volatile component 9 from the demineralized dry coal 3a is produced.

  The mixing step S5 is a step of mixing the demineralized carbonized carbon 4 obtained in the carbonization step S4 and the demineralized dry coal 3b fractionated in the fractionation step S3, and in the fractionation step S3, The separated decalcified dry coal 3b is fed into the mixer together with the deashed carbonized coal 4 and stirred so as to be uniformly mixed, thereby producing the deashed mixed coal 5.

  At this time, the mixing ratio of the demineralized carbonized coal 4 and the demineralized dry coal 3b is the oxygen content of the demineralized carbonized coal 4 and the demineralized dry coal 3b, the deashed carbonized coal 4 and the demineralized dry coal 3b. It is adjusted appropriately according to the mercury content. This is because the oxygen content and mercury content of the deashed dry coal 3b can be obtained by the processing conditions and analysis of the drying step S2, and the oxygen content and mercury content of the deashed dry distillation coal 4 are the same as those of the dry distillation step S4. This is because it can be obtained by processing conditions and analysis.

  Therefore, according to the method for producing the modified coal according to the present embodiment, the low quality coal 1 is dry deashed to remove the ash 7 from the low quality coal 1, so that the mercury in the low quality coal 1 can be obtained together with the ash 7. It can be physically removed, and the deashed dry coal 3a obtained by dry deashing and drying the low quality coal 1 is dry-distilled to chemically remove mercury in the deashed dry coal 3a together with the volatile components 9. Therefore, the obtained demineralized mixed coal 5 has a reduced mercury content. Further, the demineralized dry coal 4 obtained by dry deashing, drying and dry distillation of the low quality coal 1 and the separated deashed dry coal 3b are mixed to obtain the deashed mixed coal 5; Compared with this, the heat generation amount can be increased. The obtained deashed mixed coal 5 contains deashed carbonized coal 4 obtained by dry deashing, dried and dry distilled, and deashed dry coal 3b obtained by dry deashing, dried and fractionated. Therefore, the yield is higher than dry-distilled carbon obtained by dry distillation. That is, the productivity of the deashed mixed coal 5 with a reduced mercury content and an increased calorific value can be improved.

[Other Embodiments]
In the above-described embodiment, the demineralized dry coal 4 obtained by dry deashing, drying and dry distillation of the low quality coal 1 and the separated deashed dry coal 3b are mixed to obtain the deashed mixed coal 5. The method for producing modified coal for obtaining a coal whose surface is inactivated from the deashed mixed coal 5 by an inactivation treatment in contact with a predetermined treatment gas (oxygen-containing gas) has been described. It is also possible to do. Further, after obtaining coal whose surface is deactivated from the demineralized mixed coal 5 by an inactivation treatment in contact with a predetermined treatment gas (oxygen-containing gas), a binder such as corn starch or asphalt is mixed. A method for producing modified coal that produces compacted coal by compressing (1200 kg / cm ² × 300 to 450 ° C. (preferably 350 to 450 ° C.)) and forming it into a solid briquette such as a cylindrical shape or a tadon shape. It is also possible.

  Since the method for producing modified coal according to the present invention can reduce the mercury content and improve the productivity of coal with an increased calorific value, it can be used extremely beneficially industrially.

1 Low grade coal (low quality coal)
2 Deashed coal 3, 3a, 3b Deashed dry coal 4 Deashed carbonized coal 5 Deashed mixed coal 7 Ash 8 Water 9 Volatile component S1 Dry deashing step S2 Drying step S3 Preparative step S4 Drying step S5 Mixing step

Claims (6)

A dry deashing process for dry deashing coal to obtain deashed coal from which ash has been removed;
A drying step of drying the decalcified coal obtained in the dry deashing step to obtain deashed dry coal;
A fractionation step of fractionating a portion of the demineralized dry coal obtained in the drying step;
A carbonization step of carbonizing the demineralized dry coal obtained in the drying step to obtain demineralized dry coal;
A reforming step comprising mixing the deashed carbonized coal obtained in the carbonization step and the demineralized dry coal fractionated in the fractionation step to obtain a demineralized mixed coal. Coal production method. A method for producing the modified coal according to claim 1,
The drying step is performed using a dryer with a structure that dries the coal with a carrier gas and discharges the carrier gas.
The method for producing modified coal, wherein the sorting step is performed by using the wind jar of the dryer. A method for producing a modified coal according to claim 2,
The method for producing reformed coal, wherein the amount of the dry coal to be fractionated in the fractionation step is adjusted by a flow rate of the carrier gas that circulates to the windmill. A method for producing reformed coal according to any one of claims 1 to 3,
The dry deashing step includes a pulverizer that pulverizes the dry coal and the carbonized carbon, and a magnetic separation device that separates and removes the ash from the dry coal and the carbonized carbon pulverized by the pulverizer by magnetism. A method for producing modified coal, characterized in that A method for producing reformed coal according to any one of claims 1 to 3,
The dry deashing step is performed using an airflow separation device that separates and removes the ash from the dry coal and the dry distillation coal by airflow. A method for producing reformed coal according to any one of claims 1 to 5,
The method for producing modified coal, wherein the coal is low-grade coal.

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