JPS6354493A - Manufacture of tar of good quality in coke oven - Google Patents

Abstract

PURPOSE:To obtain tar of good quality advantageously, by driving charging coal before being charged into the carbonization chamber of a coke oven, and lightly charging the dried coal so as to keep the charging height lower than the lower end of a leveler hole, thereby effecting carbonization without using the leveler. CONSTITUTION:Charging coal is dried before being charged into the carbonization chamber of a coke oven. This dried coal is lightly charged so as to keep the charging height lower than the lower end of a leveler hole, thereby effecting carbonization without using the leveler. Predrying of charging coal reduces the angle of repose thereof and prevents the formation of a heap when charged; therefore, leveling becomes unnecessary. Since the predrying also increases the bulk density of charging coal, the volume of the space at the top of an oven will be greater than when moistened coal is lightly charged even with the same amount of charging coal. As a result, the residence of gas containing tar is lengthened, the effect of thermal reforming of tar is improved, and tar of good quality can thus be obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing high-quality tar in a coke oven, and in particular, enables light charging without relying on a leveler, thereby producing high-quality tar. Relating to a method of manufacturing.

(Prior art) The amount of coal charged into the coke oven carbonization chamber is reduced, that is, so-called light charging is performed, the temperature of the gas passage in the upper part of the coke oven is increased, the residence time of the gas is increased, and the by-products are thermally reformed. The technology for testing has been known since before the 1940s.

For example, Japanese Patent Laid-Open No. 61-9491 proposes a method of increasing the temperature by installing a forced heating device in the furnace top space. Furthermore, Japanese Patent Laid-Open No. 59-172584 proposes a method in which a leveler device can be set arbitrarily in the vertical direction to match the height of the charged coal, thereby making it possible to level light equipment accidents.

(Problems to be Solved by the Invention) In the above conventional method, when attempting to lower the level below the lower end of the repeller hole by reducing the amount charged into the carbonization chamber,
There was a problem in that it was impossible to smooth out the mountains that formed when charging coal from above the coking chamber using a repeller, and it became impossible to make the height of the charged coal uniform.

In addition, adjusting the height of the repeller according to the charging height in the carbonization chamber requires the installation of special equipment, which not only increases equipment costs but also increases operational and maintenance costs. Ta.

Furthermore, when installing a forced heating device in the furnace top space, there were problems in terms of equipment costs and maintenance.

The present invention enables light charging without the need for such special equipment, and makes the height of charged coal substantially uniform without using a repeller, resulting in a reduction in the height of the charged coal in the furnace top space. The aim is to provide a method in which tar is effectively thermally reformed as it passes through this space by utilizing temperature history and residence time.

(Means for Solving the Problem) The present inventor conducted research to solve the above problem, and noticed that drying coal improves its fluidity as a powder, and When adjusting the height of coal charging, if the charging coal is pre-dried, even if the charging coal height is within the range that the fixed repeller can reach, the high fluidity of powdered coal will substantially reduce the charging coal height. It was discovered that the height became constant, and not only was there no need for a variable repeller, but there was also no need to operate a fixed repeller.

Furthermore, it is known that the temperature in the furnace top space increases even in the case of normal wet coal charging due to light charging or an increase in heating temperature, but when the charged coal is dried, the temperature in the furnace top space increases. It was found that the width is increased compared to the case of wet coal charging.

That is, in the coke oven operation of charging coal into a coke oven and carbonizing it, the present invention dries the charged coal before charging it into the carbonization chamber of the coke oven. This is a method for producing high-quality tar in a coke oven, characterized by carrying out light charging with a height as low as the lower end of the repeller hole, and carbonizing it without using a repeller.

The dryness of the charged coal is such that the moisture content is 6% by weight or less, preferably 5% by weight or less. It is known that when coal is dried, the angle of repose becomes smaller because the cohesive adhesion force between the coal particles due to moisture is reduced and the fluidity of the coal as a powder increases.

When charging coal into the coke oven carbonization chamber, it passes through 4 to 5 charging ports into the carbonization chamber, so in the case of normal wet coal charging with a large angle of repose, the charging port is placed directly below the charging port. Several small mounds are formed, and in order to uniformly heat the charged coal, only leveling with a repeller is necessary.

In the case of dry charcoal, self-
Because of the leveling property, variations in charging height in the furnace length direction are reduced, and leveling with a leveler is not necessary.

FIG. 1 shows a comparative example of the height of charged coal for wet coal (dotted line) and dry coal (solid line) in a carbonization chamber when a repeller is not used. 3 indicates the charging port, and 4 indicates the riser pipe.

The furnace top space temperature gradually rises as carbonization progresses, but since the moisture evaporation period is shorter in the case of dry coal charging, the furnace top space temperature increases compared to the case of wet coal charging. reach higher levels in a shorter time. Since the main generation period of tar is in the first half of carbonization, the thermal reforming conditions of tar are advantageous in the case of dry coal charging where the furnace top space temperature becomes high in the early stage of carbonization.

As mentioned above, by light charging, the furnace top space temperature (gas passage temperature)
Although it is known that tar can be reformed by increasing the residence time of the gas and thus the tar, if light charging is carried out below the lower end of the leveler hole, it can only be leveled by the leveler. By charging dry coal, only leveling with a repeller is required, and the furnace top space temperature increases due to dry coal charging.The combination of dry coal charging and light charging has a great effect, and this is the result of the present invention. This is the aim.

The disadvantages of charging dry coal are that if the dryness is increased too much, there is a possibility of pulverized coal explosion if it mixes with air, and that dust is generated during charging. This can be avoided by closed charging with an oxygen-free gas, such as an inert gas or coke oven gas.

There is a drawback that pulverized coal is sucked out into the riser tube in the early stages of carbonization, resulting in a large amount of ash in the tar, but this can also be solved by installing two riser tubes in one carbonization chamber and directing the gas immediately after charging into separate lines. This can be avoided by means such as suction.

The disadvantages of light charging are that the amount of charging per charge decreases, resulting in a decrease in coke production, and that the amount of heat consumed by carbonization increases; however, in the case of dry coal charging,
The combination of light charging and dry coal charging improves productivity by increasing the bulk density of the charged coal and shortening the carbonization time, and reduces the disadvantages of light charging. ,
This is an extremely effective method industrially.

(Function) When performing light charging where the charged coal level in the coking chamber is lower than the lower end of the leveler hole, a normal leveler cannot function as a leveler, but by charging dry coal, the angle of repose can be improved. becomes smaller, thus eliminating piles during charging and eliminating the need for leveling. Also, the bulk density is large, and there is no need for compression using a repeller.

It is known that the lower the charging height, the higher the furnace top space temperature, but in the case of dry coal, the furnace top space temperature is even higher than that of wet coal. As the bulk density increases, the volume of the furnace top space increases even with the same amount of charged coal compared to when wet coal is lightly charged, and the residence time of gas containing tar becomes longer, and when coke production is reduced, heating flue Even if the temperature is lowered, good quality tar can be obtained.

(Example) The coal content ratio of charging coal is the same, and the moisture level is 9.
(charging coal A: wet coal) and 5 char (charging coal B: dry coal) were prepared, and according to AS'TM, for charging coal A and H, a constant hopper height of 55° W) was prepared. From constant volume (863
The angle of repose and bulk density were measured when the sample was allowed to fall naturally into a container containing crA.

The results are shown in Table 1. In the case of dry charcoal, the angle of repose became smaller and the bulk density became larger.

Next, charge coals A and B are charged into the actual furnace, and the furnace temperature is constant (114
It was actually carbonized under the conditions of 0°C).

The charging amount was set so that the charging height in the carbonization chamber was up to the leveler mouth (standard height) and 0.40 m below the leveler, and the furnace top space temperature was measured throughout the entire carbonization period, and the generated tar was collected at the same time. Specific gravity (SG) and toluene insoluble content (TI)
measurements were taken.

Figure 2 shows the change in furnace top space temperature.

The lower the charging height, the higher the furnace top space temperature.

In the case of dry coal, the temperature in the furnace top space was higher than that of wet coal.

Table 2 shows the specific gravity of tar (8G) and the toluene insoluble content (TI
) measurement results are shown.

It is clear that when a light charge of dry coal is used, the specific gravity and toluene insoluble matter are the largest, and that this allows for the production of high-quality tar.

Table 1 (Effects of the Invention) According to the present invention, the self-leveling property of dry coal not only eliminates the need for a leveler, but also reduces the time during the temperature rise in the furnace top space compared to the case of normal wet coal charging. Because of its large size, the effect of thermal reforming of tar by light charging is remarkable, and it is of extremely high practical value industrially.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the height of charged coal in a coke oven carbonization chamber type showing one embodiment of the present invention, and Fig. 2 is an explanatory diagram of the elapsed carbonization time (hr
) is a chart showing changes in furnace top space temperature.

Claims (1)

[Claims] In coke oven work where charged coal is charged into a coke oven and carbonized, the charged coal is dried and the height of the charged coal is leveled before charging the charged coal into the carbonization chamber of the coke oven. A method for producing high-quality tar in a coke oven, characterized by carrying out light charging lower than the bottom end of the hole and carbonizing it without using a leveler.