JPH07118660A - Coke oven program heating method - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent troubles due to carbon deposition in the upper space of the carbonization chamber and reduce the amount of heat required for carbonization. [Composition] In a program heating method in which the amount of heat supplied to the flue of a coke oven is changed with time, the temperature in the upper space of the carbonization chamber is kept at 800 ° C or lower in the first half of the carbonization until the dehydration of the coal bed in the carbonization chamber is completed. In the latter half of the carbonization where the inside temperature of the coal bed in the carbonization chamber reaches 600 ° C or higher, the amount of heat supply is reduced and the carbonization is performed in the latter half of the carbonization to increase the caloric supply to the calorific value in the case of constant heating at the same operation rate and perform carbonization. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmed heating method for improving the efficiency of carbonization when coal is carbonized in a coke oven to produce coke.

[0002]

2. Description of the Related Art Combustion control in a coke oven is one of the most important tasks from the viewpoint of ensuring the quality of coke, reducing the basic unit of heat quantity, stabilizing the furnace operation, and preventing damage to the furnace body.
In the furnace temperature management, the temperature level of the entire furnace group is stably maintained at a temperature corresponding to the operating rate, and the temperature distribution in the furnace length, furnace height, and furnace group direction is properly adjusted so that coal carbonization proceeds uniformly. Has been maintained. In the normal operation of the coke oven, the amount of fuel gas and gas calorie supplied to each combustion chamber is constant and the amount of heat supplied to the combustion chamber is constant from the charging of coal to the firing of the red hot coke. It is in operation.

In addition to the conventional dry distillation method, there has been proposed a method for producing a high quality coke or reducing the heat quantity required for dry distillation by changing the amount of heat supplied in the dry distillation process.
For example, a method of setting a heating pattern so that the temperature rising rate in the softening and melting zone of coal is 5 ° C./min or more while maintaining the temperature of the coke discharged from the kiln at the same level as in the normal operating method (Japanese Patent Laid-Open No. 58-222183). Gazette), a method of switching from a large flow rate heating at the initial stage of carbonization to a small flow rate heating when the temperature in the coal reaches 350 to 700 ° C. (Japanese Patent Laid-Open No. 59-179581), and the charged coal is softened and melted. Set a target value for the heating rate in the temperature range and the coke temperature from the kiln, set a heating pattern based on this, and compare the actual value of the heating rate during operation with the target value of the heating rate. To obtain the deviation and correct the subsequent heating pattern including the temperature of the output oven coke.
No. 3-268794) has been proposed.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The methods disclosed in JP-A No. 2183, JP-A-59-179581 and JP-A-63-268794 supply a large amount of heat at the initial stage of carbonization in order to increase the temperature rising rate in the softening and melting zone of coal. , The basic idea is to supply a small amount of heat in the latter part of carbonization. Further, these carbonization methods aim to control the carbonization pattern in the furnace width direction, and are adjusted so that carbonization proceeds uniformly in the furnace height direction. However, in these methods, if the furnace height direction is heated up and down uniformly, the temperature of the coke oven gas generated in the upper space of the carbonization chamber becomes high, and carbon deposition due to thermal decomposition of tar in the upper space of the carbonization chamber increases. In addition to the occurrence of operational troubles due to the carbon adhering to the furnace wall, the sensible heat of the generated gas taken out of the furnace increases, which is a cause of the deterioration of the heat quantity required for carbonization.

In each of the above methods, the carbonization in the upper part of the carbonization chamber is carried out by the uniform progress of dry distillation in the furnace height direction.
The formation of the coke layer progresses from the initial stage of carbonization, and the steam generated in the coal layer does not break the coal softening layer with high ventilation resistance in the upper part of the furnace, easily flows to the heating wall side, and steam exchanges heat with the high temperature heating wall. Has a drawback that the carbonization rate decreases and the carbonization rate decreases.

The object of the present invention is to solve the above-mentioned problems of the prior art. Coke capable of preventing troubles due to carbon precipitation in the upper space of the carbonization chamber and reducing the amount of heat required for carbonization by improving the carbonization efficiency. It is to provide a program heating method for a furnace.

[0007]

[Means for Solving the Problems] The inventors of the present invention have made extensive studies to achieve the above object. As a result, a large amount of hydrocarbon gas containing tar, which is a raw material for the carbon deposition reaction, is generated in the first half of the carbonization, especially until the dehydration of the coal layer is completed. By lowering the upper space temperature, it is possible to prevent the temperature of the coke oven gas generated in the upper space of the carbonization chamber from rising, and to suppress the carbon deposition due to the thermal decomposition of tar, etc., and to suppress the sensible heat of the evolved gas taken out of the furnace. Can be lowered,
Moreover, it was clarified that the reduction of the carbonization rate could be prevented, and the present invention was reached.

That is, according to the present invention, in the program heating method in which the amount of heat supplied to the flue of the coke oven is changed with time, the temperature in the upper space of the carbonization chamber is 800 ° C. in the first half of the carbonization until the dehydration of the coal bed in the carbonization chamber is completed. In the latter half of the carbonization, where the heat supply is reduced so that the temperature in the coal inside the coal bed is 600 ° C or higher, the heat supply is increased above the heat in the case of constant heating at the same operation rate to carry out the carbonization. This is a programmed heating method for a coke oven characterized by being performed.

[0009]

In the present invention, the temperature in the upper space of the carbonization chamber is 80 during the first half of the carbonization until the dewatering of the coal bed in the carbonization chamber is completed.
In the latter part of carbonization where the heat supply is reduced to 0 ° C or less and the coal inside temperature of the coal bed inside the coal bed becomes 600 ° C or higher, the heat supply is increased to the heat amount in the case of constant heating at the same operation rate. By carrying out carbonization, the hydrocarbon gas containing tar, which is a raw material for the carbon deposition reaction that is often generated during the first half of carbonization, especially before the completion of dehydration of the coal bed, causes the carbon deposition reaction due to the thermal decomposition of tar to rapidly increase. 800 to increase
Since it is not heated above ℃, carbon precipitation in the upper space of the carbonization chamber can be suppressed, and the generated gas can be discharged to the outside of the coke oven at a lower temperature. The amount of heat required can also be reduced. Moreover, lowering the furnace temperature in the upper part of the furnace during the first half of the carbonization can delay the formation of the coal softening layer / coke layer in the upper part of the carbonization chamber, and can keep the ventilation resistance in the furnace high direction low. The steam generated in the coal bed during carbonization is easier to flow to the upper part of the furnace on the lower temperature side than the heating wall side of high temperature, and the steam flows out at a lower temperature in the upper space. Can be reduced.

On the other hand, in the latter half of the carbonization where the temperature in the charcoal is 600 ° C. or higher, most of the generated gas is hydrogen gas, and the amount of hydrocarbon gas containing tar is small, and the heat supply is increased in the latter half of the carbonization. Even if the furnace temperature is raised by the above, the carbon deposition in the upper space of the carbonization chamber can be suppressed low. Further, since the effect of promoting dry distillation by the outflow of steam to the upper part of the furnace has already been completed, it is necessary to raise the temperature of the furnace to recover the delay of dry distillation in the upper part of the furnace in order to improve the efficiency of dry distillation in the whole dry distillation process.

In the present invention, the temperature of the upper space of the carbonization chamber in the first half of the carbonization is set to 800 ° C. or lower because the hydrocarbon gas containing tar, which is often produced in the first half of the carbonization when the temperature of the upper space of the carbonization chamber exceeds 800 ° C. This is because the carbon deposition reaction due to thermal decomposition rapidly increases, causing problems due to carbon deposition on the upper furnace wall of the carbonization chamber. On the other hand, the temperature in the charcoal when increasing the heat supply in the latter half of the carbonization is 600 °
The reason is that when the temperature in the charcoal is 600 ° C or higher, most of the generated gas is hydrogen gas, and the amount of hydrocarbon gas containing tar is small. Therefore, the heat supply is increased to raise the furnace temperature. However, carbon precipitation is small and carbon trouble does not occur.

As a coke oven to which the method of the present invention can be applied, not only an ordinary chamber type coke oven but also a vertical coke oven having a vertical flue or a horizontal flue can be applied. In addition, the increase or decrease of the heat supply in the present invention is performed by changing the upper space temperature of the carbonization chamber to 800 in the first half of the carbonization.
Below ℃, and the temperature in the coal inside the coal bed is 600 ℃
In the latter half of the dry distillation as described above, any method may be used as long as the heat supply can be increased beyond the heat supply in the case of constant heating at the same operating rate. For example, in a normal chamber furnace coke oven or a vertical coke oven having a vertical flue, the amount of fuel gas is reduced in the first half of the carbonization, or the total amount of heat input is reduced while supplying high-calorie rich gas. In the latter half of the dry distillation, the fuel gas amount is increased, or the total input heat amount is increased and heated while supplying low-calorie poor gas. Further, in the case of a vertical type coke oven having a horizontal flue, the heat quantity supply to the upper horizontal flue may be reduced or stopped.

[0013]

【Example】

Example 1 As shown in FIG. 1, a furnace height 2 of an electrothermal heating system capable of independently setting the temperatures in 6 stages of horizontal flues in the furnace height direction 2
Using a test coke oven 1 of 600 mm, oven width 450 mm, and oven length 1000 mm, a charging coal with a total water content of 8.5% was charged into the carbonization chamber 2 at an average charging high density of 715 kg / m ³ , and the furnace height direction was increased. Program the top flue 3 of the No. 3 with a heater and set the flue temperature to 100 for the first 10 hours.
The temperature was raised to 1150 ° C. from 0 ° C. after 10 hours to 15 hours, and the furnace temperature was changed to 1150 ° C. from 15 hours to 24 hours. In the case of the method of the present invention in which the flues 4 to 8 except the uppermost part were controlled by a heater to keep the flue temperature constant at 1150 ° C. for 24 hours and the uppermost flue was also constant at 1150 ° C. The temperature in the coal at 1.0m from the bottom of the furnace in the center of the width direction, the burn down situation judged from the change over time in the composition of the evolved gas in the upper space, the gas temperature in the upper space of the carbonization chamber 2, the brick suspended in the upper space The amount of deposited carbon was measured. Table 1 shows the measurement results
And shown in FIG. In addition, 9 is a furnace lid and 10 is a coal charging port.

[0014]

[Table 1]

As shown in Table 1 and FIG. 2, the temperature in the charcoal at the center of the furnace in the height direction during the kiln removal is higher by about 50 ° C. in the method of the present invention than in the conventional method, and dry distillation is promoted. Further, the fire time is 22.3 hours in the conventional method and 2 in the method of the present invention.
It was shortened to 0.5 hours, and a significant effect of promoting carbonization was confirmed. The settling time is 3.5 hours in the method of the present invention, which is unnecessarily long. This means that the settling time is shortened to improve the productivity of the coke oven, or the furnace temperature is lowered to reduce the amount of heat required for carbonization. It means that the effect is extremely large.

The temperature of the upper space of the carbonization chamber in the first half of the carbonization until the dehydration of the coal layer is completed is 800 ° C. in the method of the present invention.
It is considered to be because the temperature is below about 70 ° C. as compared with the conventional method, the uppermost flue temperature is low, and the steam flows out at a temperature lower than the upper part of the furnace. In the method of the present invention,
Since the furnace temperature is raised in the latter half of the carbonization where the temperature in the charcoal is 600 ° C or higher, the upper space temperature also rises, but the average of the latter half of the carbonization remains the same as the conventional method.
Therefore, in the whole process of carbonization, the head space temperature is lower in the method of the present invention than in the conventional method, and the heat quantity required for carbonization due to the decrease in the sensible heat of the generated gas can be reduced. Further, it was also confirmed that the amount of carbon deposited on the brick suspended in the upper space was almost non-existent in the method of the present invention, and was significantly reduced as compared with 20 μm in the conventional method. It is expected that the work of burning off will be greatly reduced.

[0017]

As described above, according to the method of the present invention, in the program heating of the coke oven, the furnace temperature in the upper part of the furnace height direction is changed with time, and the furnace temperature in the upper part of the carbonization chamber is set low in the first half of the carbonization distillation. The amount of carbon deposited in the upper space of the carbonization chamber is suppressed, and the generated steam is selectively discharged to the upper part of the furnace at a low temperature.In the latter half of the carbonization, the furnace temperature in the upper part of the carbonization chamber is set high, It is possible to recover the delay of carbonization and greatly improve the efficiency of carbonization in the whole process of carbonization, and to significantly reduce the amount of heat required for carbonization.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a test coke oven used in an example.

FIG. 2 is a graph showing the relationship between the dry distillation elapsed time of the method of the present invention and the conventional method, the temperature in the upper space of the carbonization chamber, the temperature in charcoal, and the flue temperature at the top in Examples.

[Explanation of symbols]

 1 Test coke oven 2 Carbonization chamber 3 Top flue 4, 5, 6, 7, 8 flue 9 Furnace lid 10 Charging port

Claims (1)

[Claims] 1. In a program heating method in which the amount of heat supplied to the flue of a coke oven is changed over time, the temperature in the upper space of the carbonization chamber becomes 800 ° C. or lower during the first half of the carbonization until the dehydration of the coal bed in the carbonization chamber is completed. As shown in the figure, the calorie supply is reduced and carbonization is carried out, and the temperature in the coal bed in the carbonization chamber is 600 ° C.
In the latter half of the carbonization, the programmed heating method of the coke oven is characterized in that the carbonization is carried out by increasing the amount of heat supply to a value higher than that in the case of constant heating at the same operating rate.