JP7188007B2 - coke production method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing coke, and more particularly, to a method for suppressing adhesion of tar generated during the production of iron-making coke to a furnace frame or the like.

Coal charged into a coking chamber of a coke oven is carbonized by high-temperature heat supplied from combustion chambers adjacent to both sides of the coking chamber through furnace wall bricks to form coke. At that time, tar, which is a black liquid product, is produced from the coal particles.
Since tar generally contains many kinds of compounds, it is separated into various useful components and used as synthetic chemical raw materials in various fields. On the other hand, tar generated during operation in the coke manufacturing industry adheres to the furnace frame and the lower inner surface of the furnace lid knife edge that presses the furnace frame and solidifies. This impedes the sealing of the furnace lid and creates a gap between the furnace frame and the knife edge of the furnace lid.

When the gap is formed, the coke oven gas leaks through the gap and generates heat by oxidation in the vicinity of the metal fittings of the furnace lid. This deforms the oven lid hardware and causes further coke oven gas leaks. Therefore, the work of removing the tar adhering to the furnace frame or the like with a cleaner or the like is generally carried out, but a method for efficiently suppressing the growth of the tar is required.

For example, Patent Literature 1 discloses a method for suppressing adhesion of tar by deteriorating wettability between the coke oven cover and tar. In this method, we focused on the fact that refractory materials such as bricks, which were conventionally used for furnace lids, tended to adhere to tar due to their rough surface. Covering prevents adhesion of tar, etc.
Further, Patent Document 2 discloses a method of increasing the temperature of the furnace lid to suppress the adhesion of tar. Specifically, a heat-resistant gas circulation box is provided on the furnace lid, and after the inside of the heat-resistant gas circulation box reaches the combustion decomposition temperature of tar, the necessary amount of air to burn the tar is blown into the heat-resistant gas circulation box. to heat the furnace lid and suppress the adhesion of tar.

JP-A-11-80738 JP-A-2005-97500

The method described in Patent Document 1 can suppress tar adhesion near the knife edge, but when blended coal with a volatile content of 27% by mass or more is used for coke production, the hermeticity of the furnace lid is significantly deteriorated. The present inventors found that when blended coal with a volatile content of 27% by mass or more is used for coke production, the tar adhered near the kiln mouth is swept near the furnace lid by the external force during coke extrusion, and the fine powder in the coal is removed. We have obtained knowledge that the phenomenon of becoming a massive tar mixture and accumulating and depositing in the vicinity of the furnace lid becomes extremely conspicuous. Therefore, in the method described in Patent Document 1, when blended coal with a volatile content of 27% by mass or more is used for coke production, it is not possible to ensure the airtightness of the oven lid.
The method described in Patent Document 2 also has the same problem as the method described in Patent Document 1.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a method for producing coke that can maintain the airtightness of the oven lid even when blended coal having a volatile content of 27% by mass or more is used for coke production. With the goal.

In order to achieve the above object, the present invention provides a method for producing coke using blended coal having a volatile content of 27% by mass or more,
It is characterized in that the flue temperature is adjusted to raise the furnace lid temperature to 500° C. or higher, and the coke is pushed out from the coking chamber at the furnace lid temperature.
The combustion chamber is composed of a plurality of small combustion chambers, and these small combustion chambers are called "flue".

The present inventors found that when blended coal with a volatile content of 27% by mass or more is used for coke production, the tar adhering near the kiln mouth is swept near the furnace lid by the external force during coke extrusion, resulting in fine powder in the coal. It was discovered that the tar mixture became a lumpy tar mixture and deposited near the furnace lid, which hindered the sealing performance of the furnace lid.

Based on the above findings, further examination was conducted, and
When the furnace lid temperature is adjusted to 500 ° C. or higher by adjusting the flue temperature, and the coke is pushed out from the carbonization chamber at the furnace lid temperature, the tar burnout rate is higher than the amount of the lumpy tar mixture being swept and deposited near the furnace lid. It was found that there is a strong tendency to outperform (the lumpy tar mixture oxidizes and disappears).

Moreover, in the method for producing coke according to the present invention, it is preferable to set the water content of the blended coal to 5% by mass or less.

The seal plate is a metal piece provided at the base of the knife edge, and is close to the metal piece on the carbonization chamber (kiln mouth) side when the furnace lid is closed. Therefore, when the seal plate is deformed, it becomes a cause of deterioration of the sealing performance of the furnace lid. When the moisture content of the blended coal exceeds 5% by mass, the total amount of heat generated due to tar combustion during the extrusion time is large, the temperature rise of the seal plate becomes significant, and the deformation of the seal plate progresses.

According to the method for producing coke according to the present invention, the tar burnout rate is higher than the amount of the lumpy tar mixture that is swept and deposited near the furnace lid, so coke is produced from blended coal with a volatile content of 27% by mass or more. It is possible to maintain the sealability of the furnace lid even when used for

FIG. 3 is a schematic view of a coke oven lid of a coke oven carbonization chamber cut horizontally. FIG. 3 is a schematic diagram showing in which direction a gas saturated with tar concentration flows in a coke oven coke chamber.

Next, an embodiment embodying the present invention will be described with reference to the attached drawings for understanding of the present invention.

FIG. 1 shows a furnace lid 10 for opening and closing a kiln mouth 21 of a coke oven carbonization chamber.
The furnace lid 10 is roughly composed of a furnace lid body 13 that closes the kiln mouth 21, and a bar 19 that is supported at both ends by a pair of bar bearings 18 projecting forward from the furnace frame 11 and that holds the furnace lid body 13. there is
The furnace lid body 13 includes a furnace lid brick 16 inserted into the kiln mouth 21, a spring device 17 disposed between the furnace lid brick 16 and the bar 19 and pressing the furnace lid body 13 toward the kiln mouth 21, and a furnace. A knife edge 14 and a seal plate 15 are provided to seal between the lid body 13 and the furnace frame 11 .

The gas generated in the process of carbonizing the coal charged into the carbonization chamber into coke mainly passes between the coke whose volume has been reduced during carbonization and the furnace wall, and passes through the riser pipe 22 connected to the carbonization chamber. (See Figure 2). The gas generated in the vicinity of the furnace lid 10 reaches the riser pipe 22 via a route that contacts the furnace lid 10 and the furnace wall of the coking chamber near the furnace lid 10 . At that time, if the sealing performance of the furnace lid 10 is poor, the gas flows out of the system from a location with poor sealing performance.

The path of the gas until it reaches the riser pipe 22 is determined according to the amount of pressure loss. As the amount of gas generated increases, the amount of gas passing near the furnace lid of the coking chamber increases. This means an increase in the amount of tar deposits near the furnace lid.

When blended coal with a volatile content of 27% by mass or more is used for coke production, the amount of gas with a saturated tar concentration increases, and the amount of tar adhered to the furnace wall near the furnace cover is conventional (for example, the volatile content is 26% by mass When using the blended coal below), it increases significantly.

When the present inventors observed the operating conditions when using blended coal with a volatile content of 27% by mass or more, the tar attached near the kiln mouth was swept near the furnace lid by the external force during coke extrusion, It was discovered that coke powder in the coking chamber and carbon scraps scraped off in the coking chamber are involved, forming a massive tar mixture that hinders the sealing of the furnace lid. From this, when blended coal with a volatile content of 27% by mass or more is used for coke production, coping with the massive tar mixture that is swept and deposited near the furnace lid improves the sealing performance of the furnace lid. important in

In the method for producing coke according to one embodiment of the present invention, when producing coke using blended coal having a volatile content of 27% by mass or more, the furnace lid temperature is adjusted to 500 ° C. or higher by adjusting the flue temperature. After that, the coke is forced out of the coking chamber.
By maintaining the flue temperature at a high level to 500° C. or higher, the vicinity of the kiln opening including the furnace cover 10 can be kept at 500° C. or higher.

The present inventors adjusted the flue temperature and compared the case where the oven lid temperature was 500°C or higher and the case where the furnace lid temperature was lower than 500°C. The moisture content of the blended coal was kept constant at 7% by mass.
As a result, assuming a normal extrusion time (usually 3 minutes to 5 minutes, sometimes about 10 minutes in some cases), if the furnace lid temperature is 500 ° C. or higher, the lumpy tar mixture will be in the vicinity of the furnace lid. It was found that the tar burning rate tends to outweigh the amount swept to the surface.
The time during which the coke is pushed out of the coking chamber is called the pushing time, and during this time the furnace lid portion in contact with the coking chamber is exposed to the atmosphere.

On the other hand, when the furnace lid temperature is less than 500°C, there is a strong tendency for the lumpy tar mixture to be swept up and deposited near the furnace lid, making it impossible to improve the sealing performance of the furnace lid, which tends to deteriorate as the number of operations increases. It was observed.

In addition, a method of heating the inside of the furnace lid to raise the temperature of the furnace lid to 500 ° C. or higher was also performed for comparison (only the furnace lid was 500 ° C. or higher, and the flue temperature was lowered to about 400 ° C.). Since the temperature of the furnace wall is low, the effect of oxidizing and disappearing the lumpy tar mixture was low, and the tendency of the lumpy tar mixture to be swept and deposited near the furnace lid was observed.

The furnace lid temperature is preferably measured at the refractory portion (furnace lid brick 16) on the furnace lid side where the furnace lid and the furnace wall of the coking chamber face each other and are close to each other. This is because the temperature of the furnace lid can be measured immediately after opening the furnace lid with a radiation thermometer provided on the extruder side because the furnace lid is opened during coke extrusion.

The moisture content of blended coal is preferably 5% by mass or less.
If the moisture content of the blended coal exceeds 5% by mass, the total amount of heat generated by tar combustion during the extrusion time increases, the temperature rise of the seal plate 15 becomes significant, and the deformation of the seal plate 15 progresses.

When the blended coal had a moisture content of 5% by mass and a moisture content of 7% by mass, it was found that the deformation of the seal plate 15 was less advanced in the 5% by mass operation than in the operation with the moisture content of 7% by mass, and the seal plate 15 was removed. I was able to reduce the frequency of replacement.

According to the observation results of the present inventors, when the oven lid temperature is 500 ° C., compared to the case where the moisture value of the blended coal is 5% by mass, the oven lid A significant amount of tar adhered immediately after removal. This is because when the moisture value of blended coal is 5% by mass, the amount of mixed gas of steam and tar generated is small and the amount of tar reaching the vicinity of the kiln mouth is small, but when the moisture value of blended coal is 7% by mass. In the case, a large amount of mixed gas of water vapor and tar was generated, and a large amount of tar reached the vicinity of the kiln mouth.

However, no change was observed in the amount of tar adhered immediately before the furnace cover was reattached to the kiln throat in both cases where the moisture value of the blended coal was 5% by mass and 7% by mass. This is probably because the total amount of tar burned during the extrusion time is greater when the blended coal has a moisture content of 7% by mass.

Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration described in the above-described embodiment. Other possible embodiments and modifications are also included.

Verification tests conducted to verify the effects of the present invention will be described.
Table 1 shows a list of test results. The presence or absence of gas leakage was visually observed. Since the gas contains tar, it is colored and can be visually observed.

In the comprehensive evaluation of the test results, x (improper) was given when there was gas leakage, ◯ (good) was given when there was no gas leakage, and ⊚ (excellent) was given when there was no gas leakage and the seal plate replacement frequency was lower than in the conventional example.

The table shows the following.
・When the furnace lid temperature is adjusted to 500°C by adjusting the flue temperature, gas leakage disappears.
- When the furnace lid temperature is adjusted to 500°C by adjusting the flue temperature and the water content of the blended coal is adjusted to 5% by mass, the seal plate replacement frequency is reduced compared to the conventional example.
・When the flue temperature is adjusted to bring the furnace lid temperature to 450°C, gas leakage occurs.

10: Furnace cover, 11: Furnace frame, 13: Furnace cover main body, 14: Knife edge, 15: Seal plate, 16: Furnace cover brick, 17: Spring device, 18: Bar catch, 19: Bar, 21: Kiln opening , 22: riser pipe

Claims (2)

A method for producing coke using blended coal having a volatile content of 27% by mass or more,
A method for producing coke, characterized in that the flue temperature is adjusted to set the furnace lid temperature to 500° C. or higher, and the coke is pushed out from the carbonization chamber at the furnace lid temperature. 2. The method for producing coke according to claim 1, wherein the blended coal has a water content of 5% by mass or less.

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