JPH0633067A - Method for operating moisture conditioning equipment for charging coal of coke oven - Google Patents

Abstract

PURPOSE:To prevent problems of dust scattering due to overdrying from occurring and the thermal efficiency from deteriorating due to the sticking of high- moisture coal to the dryer body in starting or stopping the operation in coal moisture conditioning equipment. CONSTITUTION:This method for operating moisture conditioning equipment for charged coal is to control the moisture of charged coal to be charged into a coke oven with a wet coal moisture and feed rate to a rotary tube dryer and fed steam pressure to a heat transfer tube. In the method, the feed of wet coal is started at a prescribed time before the start of steam feed in starting the rotary tube dryer operation and stopped at a prescribed time before the stop of wet coal feed in stopping the rotary tube dryer operation. Thereby, problems of dust scattering due to overdried coal are prevented from occurring and the thermal efficiency is prevented from deteriorating due to the sticking of high-moisture coal to the dryer body. As a result, stable operation of the coal moisture conditioning equipment can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a conditioning coal manufacturing facility for adjusting the water content of the charging coal in the pretreatment of charging coal for the production of coke.

[0002]

2. Description of the Related Art In order to inexpensively produce good quality metallurgical coke in a chamber furnace type coke oven, it is necessary to use a large amount of inexpensive coking coal or non-caking coal having low cohesiveness. In a chamber furnace type coke oven, as a method for using a large amount of low-cost low-caking coking coal or non-caking coal, for example, the total water content of the charging coal normally contained in 8 to 10 wt% is 5-
Weighing charcoal charging method to reduce to 7 wt% or charging charcoal 1
Preheated charcoal charging method to dry and preheat to 70-250 ℃ to reduce total water content to 2% by weight or less, 30-40% of normal charging charcoal is blended with briquette charcoal mainly composed of non-caking coal. Known methods include forming coal blending method and adding binder to improve the binding property of charging coal.

Among the above-mentioned methods, the wet-conditioning coal charging method for reducing the total water content of the charging coal to 5 to 7% by weight is, for example, as shown in FIG. Is fed to the feed feeder 3 and cut into the rotary tube dryer 4 to heat it by exchanging heat with the steam flowing in the tube, and a large amount of water vapor evaporated in the rotary tube dryer 4 is blown by the blower 5 through the dry dust remover 6. The fine-grained coal 7 discharged to the outside of the system and adjusted to have a total water content of 5 to 7% by weight is discharged to the rotary tube dryer 4 by the discharge feeder 8.
The pulverized coal 9 discharged from the dry dust remover 6 is mixed with the pulverized coal 9 by the coke oven conveyer 10 and charged into the coke oven.

In the operation of the wet-conditioning coal equipment in the above-mentioned wet-conditioning coal charging method, the amount of wet-coal supplied to the rotary tube dryer fluctuates depending on the stock amount of the coal tower, and the pressure of steam as a heat source changes Controlled by the amount of charcoal supplied and the moisture content of the wet coal, the conditioned coal with a constant water content is charged into the coke oven. However, since the conditioning coal equipment requires a large-scale and extremely huge capital investment, it is common to install equipment suitable for coke oven treatment capacity. For this reason, if the moisture content of the wet coal rises above the control capacity of the conditioning coal facility,
As shown in FIG. 10, the moisture content of the conditioned coal rises above the set value,
Adhesion of coking coal to the inside of the rotary tube dryer body progresses, and thermal efficiency also decreases from that during normal operation. Therefore, if the operation is continued as it is, as shown in FIG. 6, the adhesion of the raw material carbon to the inside of the rotary tube dryer 4 main body proceeds. Therefore, in order to reduce the moisture content of the conditioned coal to the set moisture content, it is necessary to reduce the amount of wet coal supplied to the rotary tube dryer. However, if the supply of wet coal falls below a certain level, it will interfere with the operation of the coke oven.Therefore, this shortage has been covered by stopping the wet coal facility and transferring the wet coal directly to the coal tower. Was there.

As a method for solving the above-mentioned problems, when the coking coal for metallurgical coke is dehydrated by the conditioning coal manufacturing facility and charged into the coke oven, the moisture content of the coking coal on the outlet side of the conditioning coal facility is changed to the coke oven. Operating method in which the entire amount of only the conditioned coal that has been dehydrated by the conditioned coal manufacturing facility can be charged into the coke oven, which is adjusted according to the charging rate of the raw coal into the coke oven (JP-A-4-25592) Is proposed.

The method disclosed in JP-A-4-25592 described above continues to operate even when the water content of the wet coal supplied to the humidity control coal facility rises abnormally, and raises the water content of the humidity control coal by that amount. Since the coke is charged into the coke oven after that, coking coal advances on the inner surface of the dryer and the thermal efficiency of the dryer deteriorates. Further, if the operation of the humidifying coal facility is continued, the raw material coal is clogged in the dryer, and eventually the facility must be stopped. In addition, even during normal operation, the humidifying coal facility is normally stopped about once / day for the purpose of removing adhered coal such as the transfer belt connecting portion and inspecting each device.

[0007] When stopping the above-mentioned wet-coal equipment, in order to prevent the coking coal from adhering to the conventional dryer, as shown in FIG. 9, after the supply of wet-coal to the rotary tube dryer is stopped first, The supply of steam to the heat transfer tube, which is the heat source, was stopped. Further, when the operation of the conditioning coal facility is restarted, the steam is first supplied to the heat transfer tube, and then the supply of the wet coal is started.

[0008]

In the method of stopping and starting the above-mentioned humidity control coal facility, as shown in FIG.
When the operation is stopped and when the operation is started, the amount of heat supplied to the rotary tube dryer becomes excessive, and overdried dry coal (hatched portion) is generated. As shown in FIG. 7, the process of transferring to the coke oven and the coke oven to the coke oven are performed. Dust generation during charging is a serious problem.

An object of the present invention is to prevent adhesion to the dryer main body even when the moisture content of the wet coal supplied to the wet-conditioning coal facility rises considerably, and to prevent the operation of the wet-conditioning coal facility from being stopped and started. An object of the present invention is to provide a method of operating a conditioning coal facility that can prevent drying and dust generation.

[0010]

[Means for Solving the Problems] The inventors of the present invention have made extensive studies to achieve the above object. As a result, when the operation of the wet-coal equipment is stopped, as shown in FIG. 11, the supply of steam to the heat transfer tube is stopped first, then the supply of wet-coal is stopped, and the operation of the wet-coal equipment is started. In the above, by starting the supply of the wet coal to the dryer first and then starting the supply of the steam to the heat transfer tube, it is possible to prevent the operation of the humidity control coal facility and the overdrying at the start of the operation. But,
As shown in FIG. 10, when the time interval from the supply stop of steam to the stop supply of wet coal is too long, high-moisture coal W is generated,
If it adheres to the dryer body, the thermal efficiency will deteriorate. Therefore, by setting the time interval from the supply stop of steam to the stop supply of wet coal according to the facility capacity of the wet-coal facility, it is possible to suppress the generation of overdried coal and high-moisture coal and The present invention has been achieved by investigating that operation can be stopped and started.

That is, the present invention relates to a charging coal humidity control system for controlling the moisture content of the charging coal charged into the coke oven by controlling the moisture content and supply amount of the wet coal to the rotary tube dryer and the steam pressure supplied to the heat transfer tube. In the operation method, when the rotary tube dryer is started, the supply of wet coal is started a predetermined time after the start of steam supply, and when the rotary tube dryer is stopped, the supply of steam is stopped a predetermined time before the stop of wet coal supply.

[0012]

In the present invention, when the rotary tube dryer is started, the wet coal supply is started a predetermined time before the steam supply is started, so that the heat supply amount to the rotary tube dryer is not excessive and the product is overdried. Generation of dry coal is prevented, and dust generation during the transfer process to the coke oven and the charging into the coke oven does not increase. Also, when the rotary tube dryer is stopped, the steam supply is stopped a predetermined time after the wet coal supply is stopped.Therefore, the amount of heat supplied to the rotary tube dryer does not become excessive as in the start of operation, resulting in overdrying. Generation of dry coal is prevented, and dust generation during the transfer process to the coke oven and the charging into the coke oven does not increase.

In the present invention, the time from the start of the wet coal supply to the start of the steam supply at the start of the rotary tube dryer operation cannot be specified because it varies depending on the treatment capacity of the dryer and the residence time of the raw coal in the dryer. The time for which the moisture content of the humidity-controlled coal initially discharged from the rotary tube dryer is slightly higher than the set water content may be investigated and determined in advance. In addition, the time from the stop of steam supply to the stop of charging coal charging when the rotary tube dryer is stopped differs depending on the processing capacity of the dryer and the residence time of wet coal in the dryer as at the start of operation. However, it is possible to determine in advance by investigating the time for which the moisture content of the tempered coal discharged from the rotary tube dryer at the end stage is slightly lower than the set moisture content.

[0014]

【Example】

Example 1 Using a rotary tube dryer having a treatment capacity of 400 t / H and a residence time of raw coal in a dryer of about 10 minutes, wet carbon with a total moisture content of 9% was pulverized, and the total moisture content at the dryer outlet was 6.
When adjusting to 5%, the time from the stop of the wet coal supply to the stop of the steam supply when the rotary tube dryer is stopped is -20 minutes, -3.5 minutes, and +20 minutes. Changes in steam pressure and moisture content of the conditioned coal were measured. The result is shown in FIG. In addition, when the time from the start of wet coal supply to the start of steam supply at the start of rotary tube dryer operation is -17 minutes, +5 minutes, and +20 minutes, the controlled-conditioner coal discharge amount, steam pressure, and controlled-conditioner water content The change was measured. The result is shown in FIG.

As shown in FIG. 1, in the case of A in which the time from the stop of the supply of the wet coal to the stop of the steam supply was stopped by advancing the steam by -20 minutes, the rotary tube 10 minutes before the stop of the supply of the wet coal. The moisture content of the conditioned coal discharged from the dryer gradually increased, and it was confirmed that the high-moisture coal increased the adhesion to the dryer body. In addition, in the case of B in which the time from the stop of the supply of the wet coal to the stop of the steam supply is appropriately preceded by -3.5 minutes of steam and stopped, a small amount of the wet-conditioning coal discharged from the rotary tube dryer at the end stage is Overdrying was observed, and dust generated during transportation was not much different from that of normal conditioned coal. Furthermore, the time from the stop of wet coal supply to the stop of steam supply is +
In the case of C in which the supply of wet coal for 20 minutes was preceded and stopped, the moisture content of the wet-conditioning coal discharged from the rotary tube dryer decreased 7 to 8 minutes after the supply of wet coal was stopped, and a considerable amount of overdried coal was generated. It was generated, and dust was often generated during transportation to the coke oven.

Further, as shown in FIG. 2, in the case of D in which the time from the start of the supply of the wet coal to the start of the steam supply was -17 minutes before the steam was supplied, 30 minutes after the start of the supply of the wet coal. The over-dried charcoal was discharged up to, and dust was often generated during the transfer to the coke oven. In the case of E, in which the time from the start of supplying wet coal to the start of steam supply was +5 minutes before the start, the over-drying was found in the small amount of wet coal initially discharged from the rotary tube dryer. However, the dust generated during transportation was not much different from that of normal conditioned coal. Further, in the case of F in which the time from the start of the supply of the wet coal to the start of the steam supply is set to +20 minutes with the advance of the wet coal, the high-moisture coal is discharged from the start of the supply of the wet coal for about 40 minutes, It was confirmed that the adhesion of high-moisture charcoal inside the tube dryer body increased.

Example 2 Using the rotary tube dryer having the processing capacity of 400 t / H used in Example 1 and the raw material coal residence time in the dryer of about 10 minutes, steam is supplied from the stoppage of the wet coal supply when the rotary tube dryer is stopped. The time until supply is stopped is -10 minutes, -5 minutes, -3.5 minutes, 0 minutes, +5 minutes, +
With respect to the case of 10 minutes, changes in the amount of dust generated during transportation and the thickness of the adhered carbon layer in the rotary tube dryer body were measured. The result is shown in FIG.

As shown in FIG. 3, when the operation of the rotary tube dryer is stopped, in order to minimize the amount of dust generated during transportation and the thickness of the adhered carbon in the body of the rotary tube dryer, 3.5 minutes after stopping the supply of wet coal. It was best to stop the steam supply early. Further, if the supply of steam is stopped 3.5 minutes or more earlier than the stop of the supply of wet coal, the thickness of the adhered coal in the rotary tube dryer body can be reduced, but the amount of dust generated during transportation is increased. Furthermore, if the supply of steam is stopped later than the stop of the supply of wet coal, the amount of dust generated during transportation can be reduced, but the amount of adhered coal in the rotary tube dryer body increases.

At the start of the rotary tube dryer operation, the start of the wet coal supply is made 5 minutes earlier than the start of the steam supply to minimize the amount of dust generated during transfer and the thickness of the adhered carbon in the rotary tube dryer body. It is confirmed that it can be suppressed. When the operation of the humidifying coal facility is restarted within several hours for the purpose of checking the humidifying coal facility, as shown in FIG. By increasing the amount of wet coal supplied to the conditioning coal facility for several hours after restarting the operation of the coal facility, the moisture content of the conditioning coal charged into the coke oven is kept constant, and a stable conditioning coal charging method is implemented. It can be carried out.

[0020]

As described above, according to the method of the present invention, the dust scattering problem caused by overdried coal at the time of starting and stopping the operation of the humidifying coal facility, and the problem of drying the main body of the dryer due to high-moisture coal The decrease in thermal efficiency due to adhesion is prevented, and stable operation of the humidity control coal facility can be implemented.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the time from the stop of the supply of wet coal to the stop of the steam supply when the operation of the wet-coal equipment is stopped in Example 1, and the changes in the amount of the wet-coal delivered, the steam pressure, and the moisture content of the refined coal at the outlet of the dryer body. It is a graph which shows.

[Fig. 2] Similarly, in Example 1, the time from the stop of the supply of wet coal to the stop of steam supply at the start of the operation of the wet-conditioning coal facility, and the change in the amount of discharged wet-conditioning coal, the steam pressure, and the moisture content of the conditioning coal at the dryer body outlet It is a graph which shows a relationship.

FIG. 3 is a graph showing the relationship between the time from the stop of the wet coal supply to the stop of the steam supply, the amount of dust generation, and the thickness of the adhering layer in the dryer main body when the operation of the humidifying coal facility is stopped in Example 2.

[Fig. 4] The elapsed time before and after the shutdown of the humidity control coal equipment for several hours, the moisture content of the humidity control coal at the dryer body, the moisture content of the quality control coal at the time of charging, the amount of the quality control coal discharged, and the stock amount of the coal tower It is a graph which shows a relationship.

FIG. 5 is a system diagram of a rotary tube dryer type humidifying coal facility.

FIG. 6 is a situation explanatory diagram when the supply of wet coal is stopped after the supply of steam to the heat transfer tube is stopped when the operation of the humidifying coal facility is stopped.

FIG. 7 is a situation explanatory diagram when the supply of steam to the heat transfer tubes is stopped after the supply of wet coal is stopped when the operation of the wet coal facility is stopped and the discharge of the wet coal from the dryer main body is completed. .

FIG. 8 is a graph showing the relationship between the time when the high-moisture wet coal is supplied to the wet-conditioning coal facility and the operation is continued, the wet-coal / conditioning-coal water content, the amount of wet-conditioning coal discharged, and the thermal efficiency. .

[Fig. 9] A case where the supply of steam to the heat transfer tube is stopped after the supply of the wet coal is stopped when the operation of the wet coal facility is stopped and the discharge of the wet coal from the dryer body is completed, and the case of the wet coal facility It is a graph showing the relationship between the elapsed time when the supply of wet coal is started after starting the supply of steam to the heat transfer tube at the start of operation, and the amount of steam supply, the amount of adjusted-humidified coal discharged, and the adjusted-humidified coal water content. .

FIG. 10 is an elapsed time when the supply of steam at the time of the operation stop and the start of the supply of the wet coal at the start of the operation are accelerated in order to suppress the dust generation at the time of the operation stop and the operation start of the wet-coal facility. It is a graph which shows the relationship between the amount of steam supply, the amount of humidified coal discharged, and the moisture of the humidified coal.

FIG. 11: Elapsed time when the supply of steam when the operation of the humidifying coal facility is stopped and the start of supplying the wet coal when starting the operation are set to the optimum time, the steam supply amount, the amount of the adjusted coal, and the adjustment amount It is a graph which shows the relationship with wet coal moisture.

[Explanation of symbols]

 1 Wet coal hopper 2 Conveyor 3 Supply feeder 4 Tube dryer 5 Fan 6 Dry dust remover 7 Fine coal 8 Emission feeder 9 Pulverized coal 10 Coke oven conveyor

Claims (1)

[Claims] 1. A method of operating a charging coal humidity control facility, wherein the water content of the charging coal charged into a coke oven is controlled by the moisture content and supply amount of the wet coal to the rotary tube dryer and the steam pressure supplied to the heat transfer tube. The coke is characterized in that when the operation of the rotary tube dryer is started, the supply of the wet coal is started a predetermined time after the start of the steam supply, and when the operation of the rotary tube dryer is stopped, the supply of the steam is stopped a predetermined time after the stop of the supply of the wet coal. Operating method of furnace charging coal humidity control equipment.