JP2565064B2 - How to transfer and load coal to the coke oven - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transporting and charging coal for charging dried or preheated coal to a coke oven during the production of coke.

[0002]

2. Description of the Related Art As one of coke manufacturing technologies, there is a dry preheated carbon technology. This is to increase or equalize the bulk density of coal in the carbonization chamber by drying or preheating the raw material coal in advance when charging the coal to the coke oven, and to produce effects such as reduction of the amount of dry distillation heat. It is a technology that aims to stabilize operations, improve productivity, improve quality and stabilize it.

However, while this dry preheated coal technology has the above-mentioned effects, the amount of dust generated in the transfer process from drying / preheating to carbonization and the coke oven increase with the decrease of water content in the coal. Since there are also environmental, operational and safety issues, such as an increase in the amount of coal outflow (carryover) from the rising pipe during coal charging to the It has not been widely adopted.

In order to solve these problems, for example, a technique of using a hermetically-sealed chain conveyor to introduce carbon dioxide from an inlet while introducing an inert gas (see Japanese Patent Laid-Open No. 51-86501), Technology for air flow transport of active gas as a carrier (JP-A-52-132002), a rally carrier having a hopper capable of shutting off the atmosphere by supplying an inert gas, from a storage device to a charging target kiln. A technique for suppressing dust generation during transportation and carbonization and for avoiding the risk of dust explosion has been proposed, such as a technique for transportation (Japanese Patent Laid-Open No. 58-185681). Further, a technique for preventing carry-over by preventing dust generation by destroying and separating a pseudo-particle material in which fine powder in coal is coarse-grained in a drying / preheating or a subsequent step (Japanese Patent Laid-Open No. 62-62 (192486 publication)
Is proposed.

However, the techniques disclosed in the above-mentioned JP-A-51-86501, JP-A-52-132002 and JP-A-58-185681 all use a closed structure and an inert gas. Although it is used, it is highly effective in suppressing dust generation during transportation and at the coal charging port, but it is not effective in reducing the carry-over amount because it is carbonized while the raw coal contains fine powder. In the process, pulverization or destruction of pseudo particles progresses, the ratio of fine powder contained in the raw coal increases, and there is a serious problem that the quality of coke deteriorates.

The carryover amount can be reduced by using the method of separating the fine powder portion in advance, which is disclosed in JP-A-62-192486. However, it is necessary to incorporate a special device for destroying the pseudo particles to increase the separation rate of the fine powder in the latter stage of the drying / preheating machine, and further, since the separation of the fine powder is performed immediately after the drying / preheating,
There is a problem that pulverization progresses during the transportation process up to carbonization and new fine powder is generated, and it cannot be said that the technique is sufficiently effective as a technique for reducing carryover.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and provides a special device for destroying pseudo particles during the transportation and charging of dried or preheated coal into a coke oven. The present invention proposes a method of effectively suppressing carryover at the time of carbonization without providing the above, and effectively recovering and using the fine powder contained in the raw coal as a raw material for a coke oven.

[0008]

[Means for Solving the Problems] The inventors of the present invention conducted a study of an air flow transfer technology in the process of transferring a dried / preheated coal to a coke oven and developing a new technology for carbonization. I got new knowledge of. In other words, (a) When dry or preheated coal is transported by air flow, it is a closed system, so no dust is generated outside the system, but it remains in the coal during the transport process. While the water content is evaporated to some extent, the pseudo particles are destroyed by the contact and friction between the coal particles and between the coal and the pipe wall. For this reason, the use of air transport technology does not require a special device for destroying the pseudo particles.

(B) In the solid-gas separation step during air flow transportation, it is usually required to reduce dust entrained in the gas phase side as much as possible to enhance the recovery of solids, but it is not solid-gas separation but fine powder separation. Based on the idea of carrying out the above, it is possible to separate and remove the fine powder portion which is easily dusted by entraining the fine powder portion with the gas on the gas phase side and collecting the coal containing a large amount of coarse particles on the solid phase side. . As a result, it is possible to charge the carbonization chamber only with the coarse-grained portion, and carry-over can be significantly suppressed.

(C) The amount of the fine powder portion to be separated varies depending on the drying preheating condition and the air flow transportation condition. In consideration of the amount balance and the total energy cost balance including the coke oven and the blast furnace, it is determined whether the fine powder portion is used as the blast furnace blown fuel or the coke oven raw material. The pulverized coal recovered can be used as it is when it is used as a blast furnace fuel by pulverized coal combustion, but dust prevention measures are required when it is used as a raw material for a coke oven. In order to prevent dust generation, it is sufficient to increase the particle size so that the particle size is not destroyed during carbonization and can be maintained at a certain level or more, preferably 0.1 mm or more. . By mixing the fine powder that has undergone such pseudo-particle formation with the coarse particle portion, the fine powder portion can be effectively used as a raw material for coke.

The present invention was made on the basis of the above findings, and its gist resides in the following method of transporting and charging coal.

[0012] The dried or preheated coal is conveyed by air transportation to a fine powder separating apparatus installed at the upper part of a charging target kiln of a coke oven, and in the fine powder separating apparatus, a gas phase containing fine coal and coarse-grained coal are A method for transporting and charging coal to a coke oven, characterized in that the coal is separated into main coal and the coarse coal is mainly charged into a charging target kiln.

[0013] The fine powder entrained on the gas phase side is collected and agglomerated, and then coarse grain coal is mixed with the main coal and charged into a charging target kiln. How to transfer and load coal into the coke oven.

The above-mentioned agglomerated particles include not only particles which are apparently agglomerated by molding or granulation but also particles which are pseudo-particles having a particle diameter of 100 μm or more.

[0015]

The method of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic view showing the construction of an example of a carrying and charging apparatus used for carrying out the method of the present invention. In order to carry out the present invention, first, the coke oven raw material coal (wet coal) a is dried or preheated by using the dryer 1 to adjust the water content. The dryer used in this case is not particularly limited as long as a predetermined preheating temperature can be obtained and the water content in the coal can be set to a predetermined value. A general heater or preheater such as a tubular rotary drying preheater may be used.

There is no particular problem as long as the water content is equal to or less than the water content (8-9% by weight) possessed by the wet coal which is a normal coking furnace coking coal, but the stability of transportation during air flow transportation, transportation efficiency and From the viewpoint of improving the fine powder separation efficiency at the time of solid-gas separation, it is desirable to be 5% by weight or less, and further increase and equalize the bulk density of coal in the coke oven,
Stabilize operations by improving dry distillation heat amount, improve productivity,
In order to further improve quality and stabilize it, it is better to reduce the amount as much as possible.

The preheating temperature may be not higher than the thermal decomposition temperature of coal, but is preferably 150 to 200 ° C. from the viewpoint of improving thermal efficiency and improving quality and productivity.

The dried or preheated coal is directly or once put in an intermediate coal tank (not shown) and then sent to the coal storage tank 3 of the coal tower by air flow transfer. Next, similarly, the powder is fed from the coal storage tank 3 to the fine powder separating device 9 by air flow conveyance, where the fine powder is separated and removed.

The fine powder separating device 9 has a cyclone type coal storage bin 10 for separating coarse coal and a gas containing fine coal and a dust collector 11, and the coarse coal separated from the gas containing fine coal is a cyclone type. Coal is stored in coal storage bin 10. The gas containing pulverized coal is introduced into the dust collector 11 such as a bag filter, and the pulverized coal c is collected and collected. The fine powder separating device 9 does not need to be special, and may be any device that can efficiently separate fine powder having a particle size that causes carryover during carbonization in the coke oven. For example, in addition to the cyclone type, a general type such as a gravity classifier can be used.
The fine powder separating device may be either a fixed type or a mobile type.

For the transportation of preheated and dried coal, it is not necessary that the entire line is vapor-phase transported. For example, it may be carried to the coal storage tank 3 by a closed chain conveyor or the like, and then switched to air flow carrying.

It is conceivable that the fine powder separating device 9 is provided above the coal storage tank 3 of the coal tower to store the coarse coal separated from the gas containing the fine coal in the coal storage tank 3. When the air flow distance is long, or when it is carried by a chain conveyor, new fine powder is generated due to contact and friction between coal particles during transfer and between coal and the pipe wall, increasing the carryover amount during carbonization. To do. Therefore,
In the coal storage tank 3, fine powder separation is not performed, but a fine powder separation device is provided in the upper part of the carbonization chamber to be charged, and if fine powder is separated and removed there, new fine powder is generated in the conveying process after separating the fine powder. Can be prevented and carryover can be suppressed.

Table 1 shows coal (coal "before drying" shown in Table 3).
Under the same conditions as in Example 1 described later, that is, using the air flow test apparatus shown in FIG. It is the result of comparing the particle size distributions before and after transporting by airflow again using the same device after removing the following fine powders. “Before air flow” is the particle size distribution after removing the fine powder, and “After air flow” is the particle size distribution after the air flow again. As shown in this table, new fine powder is generated during the transportation. Is recognized. From this result, it is clear that it is effective to separate and remove the fine powder in the coking coal by using the pneumatic transportation immediately before the charging into the coke oven.

[0024]

[Table 1]

When the dried or preheated coal is conveyed by air flow, the pseudo particles are destroyed due to the contact and friction between the coal particles and between the coal and the pipe wall during the conveying process. Therefore,
With pneumatic transport technology, no special equipment is needed to destroy the pseudo particles.

Table 2 shows the coal before "drying" in Table 3
This is also the result of comparing the particle size distributions before and after transportation by air transport from the cutting tank 12 to the tank A under the same conditions as in Example 1 described later. Table 3 shows the particle size distribution of the coal before drying and the particle size distribution after drying, showing the destruction of pseudo particles due to drying. The subsequent particle size distribution is similar to the particle size distribution after drying, and it can be seen that the fine particles with a particle size of 0.07 mm or less are increasing, and that the pseudo particles are destroyed during the transportation only by air flow transportation. That is, it is clear that if air flow transportation is used in the coal transportation process, no special device for quasi-particle destruction is required.

[0027]

[Table 2]

The carry-over amount at the time of carbonization differs depending on the crushing conditions of the raw material coal, the drying / preheating conditions, the transportation conditions, and the carbonization method (speed, order), and is therefore required for the fine powder separating apparatus 9 accordingly. Specifications (separation particle size, separation efficiency) are determined, but since most of the carry-over particles are usually less than 70 μm (0.07 mm), 0.07 mm or less,
It is desirable that the apparatus is such that particles of 0.1 mm or less can be entrained together with gas on the gas phase side and separated.
Since the present invention (invention) is intended to separate coarse particles from fine powder, the fine powder separation apparatus used in this method has an increased separation capacity as required by a general solid-gas separation apparatus, and has a particle size of 0.
It is necessary not to use a device that collects a large amount of fine powder of less than 07 mm on the solid phase side.

The coarse-grained coal recovered by the fine powder separating apparatus 9 is loaded into the carbonization chamber. The coal-charging device includes a coal-charging vehicle that receives coal for one chamber in the coal-charging chamber and then moves to the position of the coal-charging chamber for coal-charging to perform coal-charging. Gas-phase direct coal-charging device for carbonization, transporting to a fixed or mobile solid-gas separator on the target carbonization chamber by air flow through a metering tank, separating the gas and then coal-charging A conventionally used device such as a gas separation carbonization device or a closed chain conveyor carbonization device may be used.

The invention of (1) is a method of effectively utilizing the fine powder separated and removed from the dried / preheated carbon, and a binder is added to the fine powder after the separation and removal to knead it to form pseudo particles, which is used as it is, or when it is produced. After being agglomerated by a granulator or a molding machine, it is mixed with the coarse-grained portion in the coal storage bin 10 and carbonized in the carbonization chamber. Any kneader or granulator may be used as long as the pseudo particle diameter can be 0.1 mm or more, and a horizontal axis type or vertical axis type kneader or the like may be used. As a molding machine, a general one such as a double roll type or a piston type can be used.

When the above-mentioned method of the present invention is used, the dried or preheated coal is kept in a sealed state until it is charged into the coke oven, so that no dust is generated during the transportation process and during charging. . Further, since fine coal is removed from the coal to be charged, carryover from the rising pipe can be sufficiently suppressed.

[0032]

[Embodiment 1] Using the air flow test apparatus shown in FIG.
Coking coal (coal “before drying” in Table 3) was cut out under the transportation conditions shown in Table 4 and air-transported from tank 12 to tank A, and the coarse-grained portion after separation and removal of fine powder was transferred from tank A to the carbonization chamber. The amount of pulverized coal (carryover amount) contained in the exhaust gas when the corresponding tank B was carbonized was investigated. In addition,
Reference numeral 13 in FIG. 2 is a fine powder separator, which is a cyclone type.

Table 5 (1) shows the particle size distributions of the solid phase side (coarse grain coal) and the gas phase side (fine coal powder) after the raw coal is cut out and air-transported from the tank 12 to the tank A. The sampling positions are, as shown in the figure, the inlet side (post-transport sampling position) and the outlet side (vapor phase side sampling position) of the fine powder separation device 13.
, The particle size distribution of coarse coal obtained by subtracting the value of the corresponding particle size range in the particle size distribution of the sample collected at the gas-phase side sampling position from the value of each particle size range in the particle size distribution of the sample collected after transportation Is indicated as "solid phase side", and the particle size distribution of the sample collected at the gas phase side sampling position is indicated as "gas phase side". The total of "solid phase side" and "gas phase side" is 100% by weight.

Case 1 is a case where fine powder having a particle size of 0.15 mm or less is entrained in the gas phase side, and almost all fine powder having a particle size of 0.07 mm or less is contained in the gas phase side. In Case 2, the fine powder separation conditions were changed to increase the amount of fine powder with a particle size of 0.25 mm or less entrained in the gas phase, and in Case 3, the amount of fine powder entrained in the gas phase was reduced. is there.

In Table 5 (2), the amount of pulverized coal contained in the exhaust gas from tank B (carrying when the coarse particle portion after separation and removal of fine powder as described above is carbonized from tank A to tank B) The results of the survey of the excess amount are shown. The comparative example in the table is
This is a charging method corresponding to the conventional method in which raw coal is directly charged into tank A and then charged into tank B.

From the results shown in Table 5 (2), it is understood that the carry-over amount at the time of carbonization is significantly reduced by removing the fine powder. In addition, even if the recovery rate of fine powder with a particle size of 0.25 mm or less to the gas phase side is increased (Case 2), the carryover amount is Case 1 in which fine powder with a particle size of 0.15 mm or less is entrained in the gas phase side. In Case 3, where the recovery rate of fine powder with a particle size of 0.07 mm or less to the gas phase side was reduced, the carryover amount increased significantly compared to Case 1. From this, it can be said that it is not necessary to collect fine powder having a particle size of 0.25 mm or less to the gas phase side, and it is desirable to entrain fine powder having a particle size of 0.15 mm or less to the gas phase side.

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

[Table 5 (1)]

[0040]

[Table 5 (2)]

[0041]

Example 2 Fine powder (particle size distribution is shown in Table 6) which was air-transported under the same conditions as in Example 1 and was entrained in the gas phase side was recovered,
To this, 2% by weight of tar as a binder was added and granulated and agglomerated with a high-speed kneader to a particle size of 0.1 mm or more was mixed with the coarse-grained portion of tank A and carbonized in tank B, and then carbonized. The amount of carryover at that time was investigated.

The survey results are shown in Table 7. The comparative example in the table is a case where the raw material coal is directly put into the tank A and is charged into the tank B, which corresponds to the conventional method. From this result, it is understood that the fine powder separated and removed is collected, agglomerated, and then mixed with the coarse grain portion and carbonized, whereby the fine powder can be effectively used without carrying over.

[0043]

[Table 6]

[0044]

[Table 7]

[0045]

When the method of the present invention is applied when the dried or preheated coal is transferred and charged into the coke oven, the transfer,
It is possible to prevent dust generation during charging and to effectively suppress carryover during charging. Further, it is possible to effectively use the recovered fine powder as a raw material for a coke oven or the like.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an example of a carrying and charging device used for carrying out a method of the present invention.

FIG. 2 is a schematic diagram of an airflow transportation test device used in an example.

[Explanation of symbols]

1: Dryer, 2: Pipe for air flow transfer, 3: Coal storage tank, 4: Pipe for air flow transfer, 5: Coke oven, 6: Extruder, 7: Guide car, 8: Digestion trolley, 9: Fine powder separation device, 10: Cyclone type coal storage bin, 11: Dust collector, 12: Cutting tank, 1
3: Fine powder separating device, 14: Rotary feeder, a: Coking furnace raw coal (wet coal), b: Exhaust gas, c: Fine coal.

Claims (2)

(57) [Claims] 1. Dry or preheated coal is conveyed by air flow to a fine powder separator installed at the upper part of a charging target kiln of a coke oven, and in the fine powder separator, a gas phase containing fine coal and coarse particles are conveyed. A method for transporting and charging coal to a coke oven, which comprises separating the coal into main coal and charging the coarse coal mainly into a charging target kiln. 2. The fine powder entrained on the gas phase side is recovered and agglomerated, and then the coarse coal is mixed with the main coal and charged into a charging target kiln. The method for transporting and charging coal to the coke oven according to 1.