CN115315500A

CN115315500A - Method for producing carbide and apparatus for producing carbide

Info

Publication number: CN115315500A
Application number: CN202180023354.6A
Authority: CN
Inventors: 高桥茂树; 小水流广行; 谷奥亘; 小菅克志; 小胁幸男; 安田和真; 今村彰伸
Original assignee: Nippon Steel and Sumikin Engineering Co Ltd
Current assignee: Nippon Steel Engineering Co Ltd
Priority date: 2020-03-30
Filing date: 2021-03-24
Publication date: 2022-11-08
Also published as: AU2021247762A1; JP2021162168A; WO2021200520A1

Abstract

The present invention relates to a method for producing carbide and an apparatus for producing carbide. A method for producing carbide, which comprises a step of separating a component having a predetermined particle diameter or less from a material to be treated before being charged into a tank, by indirectly heating the material while moving the material to be treated in the tank, using a rotary tank furnace comprising a rotary tank, a combustion chamber for heating the circumferential surface of the tank by combustion gas, and an exhaust mechanism for discharging the gas generated in the tank to the combustion chamber.

Description

Method for producing carbide and apparatus for producing carbide

Technical Field

The present invention relates to a method and an apparatus for producing carbide, and more particularly to a method and an apparatus for producing carbide using an external heating type rotary kiln for indirectly heating an object to be treated.

Background

The rotary kiln is also called a rotary kiln, and is widely used for, for example, coal reforming, cement and ore burning, municipal refuse incineration, and livestock manure carbonization. The rotary tank furnace is largely divided into an internal heating type and an external heating type. In the internal-heat type rotary kiln, the object to be treated put into the kiln is directly heated by a high-temperature atmosphere generated by the heat generation of a burner provided in the kiln and the object to be treated itself. On the other hand, in the external heat type rotary kiln, a combustion chamber for heating the circumferential surface of the can from the outside is provided, and the object to be treated is indirectly heated by heat supplied from the combustion gas in the combustion chamber.

Compared with the internally heated rotary tank furnace, the externally heated rotary tank furnace has the following advantages: the high temperature atmosphere does not directly contact the object to be treated, and uniform heating is easily performed. Various techniques have been proposed for effectively utilizing energy or improving the treatment efficiency in such an external-heating type rotary kiln.

For example, patent document 1 describes the following technique: in order to effectively utilize energy in an external-heating type rotary kiln, a combustible gas generated from a material to be treated in a kiln is supplied into a combustion chamber through a through-hole provided in the circumferential surface of the kiln. Patent document 1 also describes the following: the pipe body which is contacted with the through hole and protrudes to the inner side of the tank is arranged, thereby preventing the processed object in the tank from falling into the combustion chamber through the through hole.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 58-124192

Disclosure of Invention

Problems to be solved by the invention

However, the technique described in patent document 1 is insufficient to prevent the micronized object to be treated from being released into the combustion chamber through the through-holes. Since the micronized object floats in the tank, even if a tube as described in patent document 1 is provided, the object enters the tube and is released into the combustion chamber through the through-hole. If the amount of fine particles of the object to be treated released into the combustion chamber increases, a load is applied to the equipment for burning the unburned fine particles in the exhaust gas treatment step of the combustion chamber, which may result in a decrease in productivity.

Accordingly, an object of the present invention is to provide a novel and improved method and apparatus for producing carbide, in which an external-heating type rotary kiln having an exhaust mechanism for exhausting gas generated in a tank to a combustion chamber is used, and release of fine powder of a substance to be treated from the tank to the combustion chamber can be suppressed.

[1] A method for producing carbide, using a rotary can type furnace comprising a rotary can, a combustion chamber for heating the circumferential surface of the can by combustion gas, and an exhaust mechanism for exhausting gas generated in the can to the combustion chamber, wherein carbide is produced by indirectly heating an object to be treated while moving in the can, the method comprising: separating a component having a predetermined particle size or less from the object before the object is put into the tank.

[2] The method for producing carbide according to [1], further comprising: processing the separated components of the object to be treated into an agglomerate; and returning the agglomerates to the object to be treated before the introduction into the tank.

[3] The method for producing carbide according to [2], further comprising a step of recovering a powdery material from the combustion chamber, wherein the powdery material is processed into an agglomerate together with the components of the separated material to be treated in the processing step.

[4] The method for producing a carbide according to [2] or [3], wherein the separating step comprises: a 1 st step of separating a component having a particle size of 1 st or less from the object to be treated; and a 2 nd step of separating a component having a particle size of 2 nd or less from the object to be treated having passed through the 1 st step, wherein in the processing step, the component of the object to be treated separated in each of the 1 st step and the 2 nd step is processed into an agglomerate.

[5] The method for producing carbide according to any one of [1] to [4], wherein the separating step comprises: a step of ventilating an air flow to the object to be treated; and recovering the components of the object to be treated scattered together with the gas flow.

[6] A carbide production facility comprising a rotary can type furnace having a rotary can, a combustion chamber for heating the circumferential surface of the can by combustion gas, and exhaust means for exhausting gas generated in the can to the combustion chamber, wherein carbide is produced by indirectly heating a material to be treated while moving the material in the can, wherein the carbide production facility further comprises classification means for separating a component having a predetermined particle size or less from the material to be treated before being charged into the can.

[7] The apparatus for producing carbide according to [6], further comprising: an agglomeration mechanism for processing the components of the treated object separated by the grading mechanism into agglomerates; and a conveying mechanism for returning the agglomerates to the object to be treated before the agglomerates are put into the tank.

[8] The apparatus for producing carbide according to [7], further comprising a recovering mechanism for recovering the powdery material from the combustion chamber, wherein the agglomerating mechanism processes the powdery material and the components of the separated material to be treated into an agglomerate.

[9] The apparatus for producing carbide according to [7] or [8], wherein the classifying means includes: a 1 st classification means for separating a component having a particle size of 1 st or less from the object to be treated; and a 2 nd classifying means for separating components having a particle size of 2 nd or less from the object to be treated having passed through the 1 st classifying means, wherein the agglomerating means mixes the components of the object to be treated separated by the 1 st classifying means and the 2 nd classifying means and processes the mixture into agglomerates.

[10] The method for producing carbide according to any one of [6] to [9], wherein the classifying means includes: a dryer for drying the object to be treated by ventilation; and a bag filter for recovering components of the object to be treated scattered together with the air flow in the dryer.

As described above, according to the present invention, in the method for producing carbide and the apparatus for producing carbide using the external heat type rotary kiln having the exhaust mechanism for exhausting the gas generated in the can to the combustion chamber, the fine powder of the object to be treated can be prevented from being released from the can to the combustion chamber.

Drawings

FIG. 1 is a longitudinal sectional view schematically showing a rotary hearth furnace included in a carbide manufacturing facility according to embodiment 1 of the present invention.

Fig. 2 is a cross-sectional view of the rotary hearth furnace shown in fig. 1.

FIG. 3 is a view showing the entire configuration of a carbide producing apparatus according to embodiment 1 of the present invention.

Fig. 4 is a graph showing an example of the particle size distribution of raw coal before charging in a conventional coal reforming facility.

FIG. 5 is a view showing the entire configuration of a carbide producing apparatus according to embodiment 2 of the present invention.

FIG. 6 is a view showing the entire configuration of a carbide producing apparatus according to embodiment 3 of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description thereof is omitted.

(embodiment 1)

Fig. 1 is a longitudinal sectional view showing an outline of a rotary hearth furnace included in a carbide manufacturing facility according to embodiment 1 of the present invention, and fig. 2 is a cross-sectional view of the rotary hearth furnace shown in fig. 1. In the illustrated example, the rotary can furnace 1 includes a can 2 and a combustion chamber 3. The tank 2 is cylindrical and rotates around a central axis O of the cylinder. In the combustion chamber 3, the external fuel supplied from the burner 4 and the combustible gas supplied from an exhaust pipe 8 described later are combusted. The can 2 is disposed to penetrate the combustion chamber 3 in a substantially horizontal direction, and the circumferential surface of the can 2 is heated by the combustion gas in the combustion chamber 3. The tank 2 is provided with a gentle slope such that the outlet side (right side in the drawing) becomes lower than the inlet side (left side in the drawing). Thereby, the object to be treated is indirectly heated while moving from the inlet side toward the outlet side in the tank 2.

The inlet side of the tank 2 is sealed by an inlet side cover 5, and the outlet side of the tank 2 is sealed by an outlet side cover 6. This allows the object to be treated to be heated in the tank 2 while the outside air is blocked. The object to be treated, which is fed from a hopper 7 provided on the inlet side of the tank 2, is heated and dried while moving in the tank 2, and is further pyrolyzed into carbide and a combustible gas. The carbide generated by pyrolysis is recovered from the outlet side of the tank 2.

On the other hand, the gas in the tank 2 containing the combustible gas generated by pyrolysis is supplied to the combustion chamber 3 via the exhaust pipe 8. As described above, the combustible gas supplied to the combustion chamber 3 through the exhaust pipe 8 is mixed with the fuel supplied from the burner 4 and is combusted with the air supplied from the air supply port 9. By supplying the combustible gas from the tank 2 to the combustion chamber 3, the fuel supplied from the outside to the burner 4 can be saved. The exhaust gas from the combustion chamber 3 is discharged through the flue 10 and treated in an exhaust gas treatment process described later. Further, a bottom chute 12 for recovering a powdery material including a powdery material to be treated discharged from the exhaust pipe 8 together with the combustible gas and fine ash generated by combustion of the powdery material to be treated may be provided in the combustion chamber 3. In addition, when the bottom chute 12 is not provided, the powder accumulated in the combustion chamber 3 is collected during maintenance.

The exhaust pipe 8 includes: an inlet port 8a facing the outlet side of the tank 2 in the vicinity of the central axis O of the tank 2; an exhaust port 8b that opens in the circumferential surface of the can 2 and communicates with the combustion chamber 3; and a pipe body 8c extending between the intake port 8a and the exhaust port 8 b. The pipe body 8c includes a bent portion for connecting to the inlet port 8a facing the outlet side of the tank 2, in addition to a straight portion extending in the cross-sectional direction of the tank 2 between the inlet port 8a and the outlet port 8 b. In other examples, the inlet port 8a may be directed toward the inlet side of the tank 2.

As described above, since the inlet port 8a is located near the central axis O, the object to be treated deposited in the tank 2 does not reach the height of the inlet port 8a as long as the object to be treated is in an appropriate amount. Even if a block-shaped object to be treated falls in the vertical direction, the inlet port 8a faces the outlet side of the tank 2, and therefore, such an object to be treated can be prevented from entering the exhaust pipe 8 from the inlet port 8 a. However, the micronized material floating in the tank 2 may enter the exhaust pipe 8 through the inlet port 8 a.

The coal reforming apparatus 100 shown in fig. 3 is an example of a carbide manufacturing apparatus. In the coal reforming apparatus 100, raw coal 101 is pulverized by a pulverizer 103 and then dried by aeration by a dryer 105. At this time, the fine-size coal contained in the raw material coal 101 (including the fine-size coal generated by the pulverizer 103) is scattered together with the gas flow, and is thereby separated from the raw material coal 101. The fine coal is discharged from the dryer 105 together with the gas flow, and recovered by the bag filter 107. On the other hand, the dried raw coal 101 (dry coal) is charged into a rotary kiln (retort) 1.

The dried coal is further dried by heating in the rotary kiln 1, and then is dry distilled. Dry distillation is a process in which coal is pyrolyzed into carbides (char) and combustible gases. The char 109 recovered from the converter furnace 1 is used as, for example, a fuel or a processing material. On the other hand, as described above with reference to fig. 1, the combustible gas is supplied from the interior of the tank 2 to the combustion chamber 3 and burned as fuel for heating the tank 2. Although not shown, part of the combustible gas may be separately recovered from the tank 2 and used as fuel, for example.

The exhaust gas from the combustion chamber 3 in the rotary kiln 1 is sent to an exhaust gas treatment step 111 through a flue 10 shown in fig. 1. The exhaust gas treatment process 111 includes a combustion furnace 113, a boiler 115, a bag filter 117, and a gas treatment machine 119. In the combustion furnace 113, unburned fuel (including combustible gas supplied from the tank 2) included in the exhaust gas is burned. The fine powder of the object to be treated released from the tank 2 to the combustion chamber 3 through the exhaust pipe 8 is also combusted in the combustion furnace 113. The heat generated in the combustion furnace 113 is recovered by the boiler 115. After the solids in the exhaust gas containing ash are collected by the bag filter 117, the exhaust gas is finally treated by the gas treatment unit 119.

As described above, in the rotary kiln 1, the accumulated and lump-shaped objects to be treated are prevented from entering the exhaust pipe 8 depending on the position and shape of the inlet port 8a of the exhaust pipe 8, and such a mechanism is not provided for the micronized objects floating in the tank 2. Therefore, if the object to be treated in the tank 2 contains a large amount of the micronized component, a large amount of the fine powder of the object to be treated is released from the tank 2 to the combustion chamber 3 through the exhaust pipe 8. In this case, as described above, a load is applied to the combustion furnace 113 or the like for burning the fine powder in the exhaust gas treatment step 111, which may result in a decrease in productivity.

Specifically, for example, even if the processing capacity of the combustion furnace 113 or the like is increased in accordance with an increase in the amount of fine powder released into the combustion chamber 3, the processing capacity of the raw coal 101 for carbonization to form the char 109 is not changed, and therefore the productivity is lowered. Further, even when the amount of fine powder discharged to the combustion chamber 3 is suppressed so that the amount of fine powder can be processed by the combustion furnace 113, the processing capacity of the rotary kiln 1 becomes excessive, and thus the productivity is lowered.

Here, conventionally, a rotary kiln type furnace is generally used without the exhaust pipe 8, and since the behavior of the fine powder as described above is not regarded as a problem, as shown by a broken line in fig. 3, the fine powder coal collected by the bag filter 107 is returned as it is to the raw material coal 101 (dry coal) and charged into the rotary kiln type furnace 1. However, the present inventors have found that in the converter 1 having the exhaust pipe 8, the fine coal contained in the raw coal 101 is released from the inside of the tank 2 to the combustion chamber 3 through the exhaust pipe 8, and the above-described problem occurs.

Fig. 4 is a graph showing an example of the particle size distribution of raw coal before charging in a conventional coal reforming facility. In the illustrated example, raw coal 101 having an original particle size of 10mm to 30mm is pulverized by the pulverizer 103 so that the set particle size thereof becomes maximum, and then dried by the dryer 105, and fine coal scattered by the dryer 105 and collected by the bag filter 107 is returned and charged into the rotary kiln 1. The graph shows the particle size distribution measured in each of the 4 input batches. These particle size distributions indicate, for example, the case where the frequency of the component having a particle size of 1mm or less is 20% to 35%. Although it is not clear what degree of particle size of coal is released from the inside of the tank 2 to the combustion chamber 3 through the exhaust pipe 8, the amount of fine powder actually burned in the combustion furnace 113 in the exhaust gas treatment step 111 is increased, and therefore it is estimated that the amount of fine powder is increased because the object to be treated contains many components having relatively small particle sizes as described above.

Therefore, as shown in fig. 3, in the coal reforming apparatus 100 of the present embodiment, the fine coal collected by the bag filter 107 is not directly returned to the raw coal 101 (dry coal) but is treated separately from the raw coal 101. In this case, the dryer 105 and the bag filter 107 constitute a classifying means for performing a step of separating components having a predetermined particle size or less from the material to be treated by a step of introducing a gas flow into the raw coal 101 as the material to be treated and a step of collecting components of the material to be treated scattered together with the gas flow. This can reduce the amount of fine powder contained in the object to be treated fed into the rotary kiln 1, and as a result, release of the fine powder of the object to be treated from the interior of the can 2 to the combustion chamber 3 can be suppressed.

By suppressing the release of the fine powder of the object to be treated from the tank 2 to the combustion chamber 3, as described above, the load on the combustion furnace 113 or the like for burning the fine powder in the exhaust gas treatment step 111 can be reduced, and the reduction in productivity can be prevented. Further, by suppressing the amount of fine powder released into the combustion chamber 3, it is possible to prevent air that is originally used for burning the fuel supplied from the burner 4 and the combustible gas supplied via the exhaust pipe 8 from being used for burning the fine powder, and as a result, it is also possible to prevent the heat generation efficiency of combustion from being lowered. Further, by suppressing the amount of fine powder released into the combustion chamber 3, it is also possible to prevent the fine powder or ash after the fine powder is burned from adhering to the inside of the combustion chamber 3 or the circumferential surface of the can 2, and to reduce the heat transfer efficiency.

(embodiment 2)

FIG. 5 is a view showing the entire configuration of a carbide producing apparatus according to embodiment 2 of the present invention. The coal reforming facility 200 shown in fig. 5 includes, in addition to the components of the coal reforming facility 100 according to embodiment 1, a caking machine 201 that processes the fine coal collected by the bag filter 107 into a cake, and a conveyor 203 that returns the cake to the raw coal 101 (dry coal) before being charged into the tank 2 of the converter furnace 1. Further, the caking agent 201 may process the pulverized material recovered from the bottom chute 12 (see fig. 1 and 2) of the combustion chamber 3 in the rotary kiln (retort) 1 together with the pulverized coal recovered from the bag filter 107 into a caking agent.

The agglomerating machine 201 is a granulator such as a briquetting machine that compacts a powder containing fine coal into granules by compression, for example. Alternatively, the agglomerator 201 may be a molding machine that kneads a pulverized material containing fine-size coal with a tar-based binder or an organic binder, and then compresses and molds the mixture. The binder as described above is mixed in a small amount, for example, 10% or less, and is gasified during heating in the rotary kiln 1, and therefore does not affect the carbonization treatment of the raw material coal 101. The particles (pseudo particles) of the agglomerates after processing by the agglomerator 201 preferably have a strength to such an extent that they are not disintegrated and re-micronized while being conveyed by the conveyor 203 or the like and heated in the tank 2.

In embodiment 1 described above, the fine coal separated from the raw material coal 101 is treated separately from the raw material coal 101 without being returned to the raw material coal 101 (dry coal). Specifically, the fine-size coal is treated by a method of recovering heat or the like by burning separately from the raw material coal 101. In this case, the productivity is improved as compared with the case where the combustion furnace 113 in the exhaust gas treatment step 111 has a treatment capacity for burning the fine coal discharged to the combustion chamber 3. In contrast, in embodiment 2, by providing the agglomerator 201, the pulverized coal can be carbonized in the rotary kiln 1 after being agglomerated. This eliminates the need for equipment such as a combustion furnace and a boiler for treating the fine coal, and improves the yield of the char 109 produced from the raw coal 101. Further, if the pulverized material recovered from the combustion chamber 3 of the rotary kiln (retort) 1 is processed into an agglomerated material together with the fine coal, the yield of the char 109 produced from the raw material coal 101 can be further improved. However, since the pulverized material collected from the combustion chamber 3 contains a large amount of fine ash, the effect of improving the yield is large in the case of fine coal.

(embodiment 3)

FIG. 6 is a view showing the entire configuration of a carbide producing apparatus according to embodiment 3 of the present invention. The coal reforming plant 300 shown in fig. 6 includes a classifier 301 into which raw material coal 101 (dry coal) having passed through a dryer 105 is fed, in addition to the components of the coal reforming plant 200 of embodiment 2. In the present embodiment, the caking agent 201 mixes the fine coal collected by the bag filter 107 with coal having a predetermined particle size or less separated from the raw material coal 101 by the classifier 301 and processes the mixture into a caking material. The agglomerates are conveyed by the conveyor 203, passed through the classifier 301, and returned to the raw material coal 101 before being charged into the tank 2 of the rotary hearth furnace 1. In the present embodiment, similarly to the above-described embodiment 2, the agglomerating machine 201 may process the pulverized material recovered in the rotary kiln (retort) 1 through the bottom chute 12 (see fig. 1 and 2) of the combustion chamber 3 together with the pulverized coal recovered by the bag filter 107 and the coal having a predetermined particle size or less separated by the classifier 301 into an agglomerated material.

The classifier 301 is a mechanical classification mechanism such as a vibrating screen device, for example, and separates coal particles having a particle size range different from that of classification by the dryer 105 and the bag filter 107 using an air flow from the raw material coal 101. Specifically, when the components (fine coal) of the raw coal 101 having the 1 st particle size or less are separated by the dryer 105 and the bag filter 107, the components of the raw coal 101 having the 2 nd particle size or less larger than the 1 st particle size are separated by the classifier 301. Here, the classifier 301 may be capable of adjusting the particle size (the 2 nd particle size) serving as a separation standard. For example, in the case of a vibrating screen device, the particle size serving as a separation standard can be adjusted by replacing and using a plurality of screens having different mesh sizes.

In the present embodiment, not only the fine coal separated by the dryer 105 and the bag filter 107 by the gas flow, but also coal having a larger (but smaller overall) particle size can be separated from the raw material coal 101 by the classifier 301. For example, when not only pulverized coal separated by a gas flow but also coal having a larger particle size may float in the tank 2 and be discharged from the exhaust pipe 8 to the combustion chamber 3, such coal can be separated from the raw material coal 101 by using the classifier 301, agglomerated by the agglomerating machine 201, and returned to the raw material coal 101. Further, although it is needless to say that the classifier 301 for separating coal having a larger particle size can separate fine coal, it is advantageous to perform classification in two stages as in the present embodiment because the fine coal is automatically separated by an air flow in the step of drying the raw material coal 101 by the dryer 105, and the fine coal is not fed into the classifier 301 and clogging of a screen is less likely to occur in, for example, a vibrating screen device.

Alternatively, coal having a larger particle size, which is separated from the raw material coal 101 by the classifier 301 and mixed with the fine coal in the agglomerator 201, may cause the fine coal in the agglomerator 201 to easily agglomerate. For example, in the case of compression molding using a pelletizer, the strength of the molded pseudo particles is improved by appropriately adjusting the particle size distribution of the material. Therefore, for example, regardless of whether or not there is a possibility of floating in the tank 2 and being released from the exhaust pipe 8 to the combustion chamber 3, coal having a particle size required for the agglomerating machine 201 to appropriately agglomerate the fine-size coal may be separated from the raw coal 101 by the classifier 301. The particle size distribution suitable for agglomeration also differs, for example, depending on the kind of coal. Therefore, the particle size serving as a separation standard in the classifier 301 may be adjusted according to the type of coal. That is, in the present embodiment, the particle size to be the separation standard can be freely set in a wider range, or the strength of the agglomerated treatment object can be improved by preparing a particle size distribution suitable for the agglomeration of the separated treatment object.

Examples

Next, examples of the present invention will be explained. In the example, the coal reforming apparatus 200 described above as embodiment 2 modifies coal. The agglomerator 201 uses a briquetting machine. In the dryer 105 and the bag filter 107, fine coal having a particle size of approximately 1mm or less is separated from the raw coal 101. On the other hand, in the comparative example, as shown by the broken line in fig. 3, the separated fine-size coal was returned as it is to the raw material coal 101 (dry coal), and the coal was reformed in the same manner. In the examples and comparative examples, the particle size distribution of the coal containing the fine-size coal was the same as that in the example shown in fig. 4. The results of examples and comparative examples are shown in table 1 below.

[ Table 1]

	Examples	Comparative example
			Proportion of flying micro powder	5％	12％
Carbide yield	54％	45％
			Amount of exhaust gas generated	40,000Nm ³ /h	43,000Nm ³ /h

Table 1: results of examples and comparative examples

In the above results, the proportion of the scattered fine powder is the mass ratio of the fine powder collected by the bag filter 117 of the exhaust gas treatment step 111 to the raw coal 101, which is contained in the exhaust gas from the combustion chamber 3. The fine powder contains ash of the fine coal which is released from the inside of the tank 2 to the combustion chamber 3 through the exhaust pipe 8 in the rotary kiln 1 and is combusted in the combustion chamber 3 or the combustion furnace 113 of the exhaust gas treatment step 111. On the other hand, the carbide yield is the mass ratio of the char 109 recovered from the rotary hearth furnace 1 to the raw material coal 101. The exhaust gas generation amount is an integrated flow amount of the exhaust gas of the combustion chamber 3 calculated based on a measurement value of a flow meter provided in the flue 10.

As shown in table 1, in the examples, the proportion of the scattered fine powder (5%) was reduced by about 40% as compared with the comparative example (12%). This is considered to be because the fine-size coal contained in the raw material coal 101 is separated, agglomerated, and then pyrolysed, thereby greatly reducing the amount of the fine-size coal discharged into the combustion chamber 3. In the examples, the carbide yield (54%) was increased by about 20% in addition to the comparative example (45%). This is considered to be because the fine coal discharged into the combustion chamber 3 in the comparative example was carbonized after being agglomerated in the examples, and the ratio of the raw coal 101 recovered as the char 109 was increased. In addition, in the embodiment, the exhaust gas generated by the fine coal is not included, and therefore the exhaust gas generated is also reduced, as compared with the comparative example in which the exhaust gas generated also includes the exhaust gas amount of the fine coal released into the combustion chamber 3.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. It is needless to say that various modifications and alterations can be made by those having ordinary knowledge in the technical field to which the present invention pertains within the scope of the technical idea described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention.

Description of the symbols

1: a rotary retort furnace (retort machine); 2: a tank; 3: a combustion chamber; 8: an exhaust pipe; 10: a flue; 12: a bottom chute; 100. 200 and 300: a coal upgrading facility; 103: a pulverizer; 105: a dryer; 107: a bag filter; 111: an exhaust gas treatment step; 201: a caking machine; 203: a conveyor; 301: a classifier.

Claims

1. A method for producing carbide, using a rotary kiln comprising a rotating kiln, a combustion chamber for heating the circumferential surface of the kiln by combustion gas, and an exhaust mechanism for exhausting the gas generated in the kiln to the combustion chamber, wherein carbide is produced by indirectly heating a material to be treated while moving in the kiln, the method comprising:

separating a component having a predetermined particle size or less from the object to be treated before the object to be treated is put into the tank.

2. The method for producing carbide according to claim 1, further comprising:

processing the separated components of the object to be treated into an agglomerate; and

returning the cake to the object to be treated before the cake is charged into the tank.

3. The method of manufacturing carbide according to claim 2, further comprising:

a step of recovering the powdery material from the combustion chamber,

in the processing step, the powdery material is processed into the agglomerate together with the separated components of the object to be treated.

4. A method for producing carbide according to claim 2 or 3, wherein,

the separating step includes: a 1 st step of separating a component having a particle size of 1 st or less from the object to be treated; and a 2 nd step of separating a component having a particle size of 2 nd or less from the object to be treated having passed through the 1 st step,

in the step of processing, the components of the object to be treated separated in the step 1 and the step 2 are processed into the cake.

5. The method for producing carbide according to any one of claims 1 to 4, wherein,

the separating step includes: a step of ventilating the gas flow to the object to be treated; and recovering the components of the object to be treated scattered together with the gas flow.

6. A carbide producing apparatus comprising a rotary can type furnace including a rotary can, a combustion chamber for heating the circumferential surface of the can by combustion gas, and an exhaust mechanism for exhausting gas generated in the can to the combustion chamber, wherein carbide is produced by indirectly heating a material to be treated while moving in the can,

the carbide producing apparatus further includes a classifying means for separating a component having a predetermined particle size or less from the object before the object is put into the tank.

7. A carbide manufacturing apparatus according to claim 6, further comprising:

a caking mechanism for processing the components of the object to be treated separated by the classification mechanism into a caking object; and

and a conveying mechanism for returning the agglomerates to the object to be treated before the agglomerates are put into the tank.

8. A carbide manufacturing apparatus according to claim 7, wherein,

further comprises a recovery mechanism for recovering the powder from the combustion chamber,

the caking mechanism processes the powder together with the separated components of the object to be treated into the caking object.

9. A carbide manufacturing apparatus according to claim 7 or 8, wherein,

the above-mentioned grading mechanism includes: a 1 st classifying means for separating a component having a particle size of 1 st or less from the object to be treated; and a 2 nd classifying means for separating a component having a particle size of 2 nd or less from the object to be treated having passed through the 1 st classifying means,

the caking means mixes the components of the object to be treated separated by the 1 st classification means and the 2 nd classification means, respectively, and processes the mixture into the caking material.

10. The carbide manufacturing apparatus according to any one of claims 6 to 9,

the above-mentioned grading plant includes: a dryer for drying the object to be treated by ventilation; and a bag filter for collecting components of the object to be treated scattered together with the air flow in the dryer.