JPH0559368A - Method for heating horizontal flue in coke oven - Google Patents

Abstract

PURPOSE:To suppress deposition of carbon in the ceiling part by regulating the temperature of upper flues of a chamber oven type coke oven having the horizontal flues so as to provide 4800 deg.C temperature of the upper space in a carbonization chamber in the first half of carbonization and then a temperature equal to or higher than that of lower flues in the latter half of the carbonization. CONSTITUTION:Horizontal flues 1 of a coke oven are heated. In the process, the temperature of the upper flues is regulated so as to provide <=800 deg.C temperature of the upper space 6 in a carbonization chamber 5 in the first half of carbonization until dehydration of a coal layer in the carbonization chamber is completed and then a temperature equal to or higher than that of the lower flues in the latter half of the carbonization in which the temperature in the coal is >=600 deg.C in the latter half of the carbonization. Thereby, deposition of carbon in the ceiling part of the carbonization chamber related to operational trouble is suppressed to improve carbonization efficiency. As a result, the calorific value required for the carbonization is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a horizontal flue when producing coke in a chamber furnace type coke oven having a horizontal flue.

[0002]

2. Description of the Related Art A vertical flue has become the mainstream of a chamber furnace type coke oven with the recent enlargement of the furnace, but a horizontal flue is used in some small coke ovens, especially a vertical type coke oven. Has been done.

FIG. 1 is a vertical sectional view of one horizontal flue of a vertical coke oven, and FIG. 2 is a horizontal sectional view of the same. In this example, as shown in the figure, the horizontal flue 1a
One horizontal flue (twin flue) by 1b
Is configured. In a vertical type coke oven, a plurality of such horizontal flues are provided in the vertical direction across the carbonization chamber 5.

The horizontal flue combustion system is a rich-gas exclusive combustion system in which a high-calorie rich gas (coke oven gas) is used as a fuel gas. One of the twin flues, 1a, is fed to a fuel gas (rich gas) 2. The preheated air 3 is introduced to burn the fuel gas, and the flue gas 4 is discharged from the other flue 1b. Usually, the flue that introduces the fuel gas 2 and the flue that discharges the combustion exhaust gas 4 are fixed. That is, the horizontal flue 1a always burns the fuel gas, and the generated high temperature flue gas 4 passes through the horizontal flue 1b and is guided to the flue gas flue 10. The combustion exhaust gas 4 discharged from the horizontal flue 1b of each stage is introduced into a heat exchange chamber (not shown) through the combustion exhaust gas flue 10 to preheat combustion air.

In the case of heating the flue in a coke oven having the above-mentioned horizontal flue, conventionally, since the carbonization is uniformly advanced in the oven height direction, the combustion amount of each flue in the oven height direction is made to be a substantially constant amount. The heating was performed after the adjustment and without changing the combustion amount with time in each carbonization cycle.

However, in such a combustion method, the temperature of the generated gas becomes high in the upper space of the furnace, and the amount of carbon deposited in the ceiling of the carbonization chamber increases, which not only hinders the operation, but also the generated gas. The large amount of sensible heat is lost due to the discharge to the outside of the furnace. Further, since the carbonization progresses uniformly in the furnace height direction, the formation of the coke layer and the softening layer in the upper part of the furnace progresses from the beginning of the carbonization, and the steam generated in the coal layer of the furnace core has aeration resistance in the upper part of the furnace. Unable to pass through a large softening layer,
The proportion of water vapor flowing to the heating wall side increases, and heat is taken from the high temperature heating wall, so that the carbonization rate decreases.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and there is no operational trouble due to carbon deposition on the ceiling of the carbonization chamber.
Moreover, it is an object of the present invention to provide a horizontal flue heating method capable of improving the efficiency of carbonization and reducing the amount of heat required for carbonization.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is "when heating a horizontal flue of a coke oven, the temperature of the upper flue is set to the upper part of the carbonization chamber in the first half of the carbonization until the dehydration of the coal bed in the carbonization chamber is completed. The coke oven horizontal is characterized in that the temperature of the space is adjusted to 800 ° C or lower, and in the latter half of the carbonization where the temperature in the coal is 600 ° C or higher, it is adjusted to a temperature equal to or higher than the temperature of the lower flue. How to heat flue ".

The above-mentioned upper flue means the flue which is at the same height or higher as the upper surface of the coal when the coal is charged into the carbonization chamber. For example, as shown in FIG.
When the height of the upper surface of the charged coal is L ₁ , the uppermost flue is the upper flue, and when the height of the upper surface is L ₂ , the two flues from the top to the second flue are the upper flues.
Usually, only the top flue is the top flue.
The lower flue means all flues located at a lower position than the upper flue.

[0010]

[Function] When the coal flue is heated by heating the flue of the coke oven, the hydrocarbon gas containing tar, which is the main factor causing the carbon deposition reaction, occurs in the first half of the carbonization, especially until the dehydration of the coal layer is completed. Is often generated. On the other hand, the precipitation reaction of carbon rapidly increases above 800 ° C. Therefore,
In the first half of carbonization, the amount of fuel (rich gas) supplied in the upper flue of the furnace was reduced, the amount of combustion was reduced, and the temperature in the upper space of the carbonization chamber was set to 800 ° C or less, so that the carbon in the ceiling of the carbonization chamber was reduced. Since the generated gas can be discharged to the outside of the coke oven at a relatively low temperature, it is possible to reduce the amount of heat required for carbonization.

Further, if the furnace temperature in the upper part of the furnace is kept low as described above in the first half of the carbonization, the formation of the coke layer and the softening layer in the upper part of the carbonization chamber can be delayed, and the ventilation resistance in the furnace high direction can be increased. Can be kept low. As a result, the steam generated in the coal bed during carbonization did not flow to the heating wall side,
Since it passes through a relatively low temperature furnace upper part and is discharged to the outside of the furnace, heat is not taken from the high temperature heating wall, dry distillation is promoted, and the amount of heat required for dry distillation can be reduced.

In the latter half of the carbonization where the temperature in the coal is 600 ° C. or higher, the amount of hydrocarbon gas containing tar is small, and even if the furnace temperature is raised, the precipitation of carbon is small. On the other hand, the dry distillation accelerating effect of steam passing through the upper part of the furnace has already been completed in the first half of the dry distillation, and it is necessary to raise the furnace temperature to recover the delay of the dry distillation in the upper part of the furnace. Therefore, the temperature of the upper flue is adjusted to be equal to or higher than the temperature of the lower flue.

As described above, the carbonization is divided into the first half and the second half,
By heating the flue under the above conditions,
It is possible to suppress the precipitation of carbon on the ceiling of the carbonization chamber, reduce the required amount of heat in the entire carbonization process, and improve the carbonization efficiency.

[0014]

EXAMPLE A test coke oven (carbonization chamber dimensions: height (H) 2.6 m, length 1 m, furnace width (W) 450 mm) shown in FIGS. 3 and 4 was used for carbonization of coal by the heating method of the present invention. The test was conducted.
3 is a vertical sectional view of the test coke oven, and FIG. 4 is a sectional view taken along the line AA of FIG. The test coke oven has 6 stages of horizontal flues 1 in the furnace height direction. Flue 1
The heating method is an electric heating method, and each flue 1 is equipped with an electric heater 9 so that the temperature of each flue 1 can be set independently.

Charging coal has a water content of 8.5% and a volatile content of 26.0%.
(Dry coal basis), ash content 9.0% (dry coal basis), and dry distillation was performed with an average charging bulk density of 715 kg / m ³ .

The dry distillation time is 24 hours, and the heating of the flue is
For the uppermost flue in the furnace height direction, the temperature was changed in the first half and second half of the carbonization by programmed heating, and the temperature was maintained at 1000 ° C for 10 hours from the start of carbonization.
The temperature was raised to 1150 ° C. by 15 hours and kept at 1150 ° C. from 15 hours to 24 hours (see FIG. 5). The flues of 5 stages except the uppermost part were controlled at a constant temperature of 1150 ° C.
For comparison, a test was also performed using a conventional heating method in which the temperature of all flues including the uppermost flue was kept constant at 1150 ° C.

In the test, the temperature in the coal at the center of the furnace in the height direction (position 1.0 m above the bottom of the furnace), the fire condition, the gas temperature in the upper space of the carbonization chamber and the amount of carbon deposition were measured during the kiln removal. did. The fire situation was judged from the change with time in the composition of the evolved gas, and the amount of carbon deposition was determined by calculating the thickness of carbon deposition on bricks suspended in the upper space of the carbonization chamber and expressing it in thickness (μm).

The test results are shown in Table 1 and FIG.

The temperature in the charcoal at the center of the furnace in the height direction during the kiln removal is about 50 ° C. higher in the method of the present invention than in the conventional method,
It can be seen that dry distillation is promoted. Further, the fire fall time was 22.3 hours in the conventional method, but was shortened to 20.5 hours in the method of the present invention, and a significant effect of promoting carbonization was confirmed. In the method of the present invention, the setting time is also 3.5 hours, which is longer than necessary, which means that the setting time can be shortened to improve the productivity of the coke oven, or the furnace temperature can be further lowered to reduce the amount of heat required for carbonization. However, it can be seen that the effect of the method of the present invention is extremely large.

In the first half of the carbonization, the temperature in the upper space of the carbonization chamber was 800 ° C. or lower in the method of the present invention, which was about 70 ° C. lower than that in the conventional method (see FIG. 5). It is considered that this is because the flue temperature at the uppermost part is low and steam is discharged from the upper part of the furnace at a low temperature. Also, the temperature in the charcoal is 600
In the latter half of the carbonization, where the temperature of the upper space was also increased by raising the furnace temperature in the method of the present invention in the latter half of the carbonization, the average in the latter half of the carbonization remained almost the same as in the conventional method. As a result, in the entire process of carbonization, the temperature of the upper space of the carbonization chamber is lower than that of the conventional method when the method of the present invention is applied, and the sensible heat removed to the outside of the furnace by the generated gas is reduced,
This proves that the amount of heat required for carbonization has decreased.

Further, the deposition amount (thickness) of carbon on the brick suspended in the upper space is small in the method of the present invention,
It was also confirmed that the precipitation of carbon was significantly suppressed as compared with the conventional method. This is expected to greatly reduce the work of burning off the carbon deposited on the ceiling of the carbonization chamber.

[0022]

[Table 1]

[0023]

EFFECTS OF THE INVENTION When producing coke in a chamber furnace type coke oven having a horizontal flue, by applying the flue heating method of the present invention, carbon precipitation is prevented at the ceiling of the carbonization chamber, and dry distillation is carried out. It is possible to improve efficiency and significantly reduce the amount of heat required for carbonization.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of a horizontal flue of a vertical coke oven.

FIG. 2 is a horizontal sectional view showing an example of a horizontal flue of a vertical coke oven.

FIG. 3 is a vertical cross-sectional view of a test coke oven used in an example of the present invention.

4 is a sectional view taken along the line AA of FIG.

FIG. 5 is a graph showing the results of the examples.

Claims (1)

[Claims] 1. When heating a horizontal flue of a coke oven,
In the first half of the carbonization until the coal bed in the carbonization chamber is completely dehydrated, the temperature of the upper flue is
A method for heating a horizontal flue of a coke oven characterized by adjusting the temperature to 800 ° C or lower, and adjusting it to a temperature equal to or higher than the temperature of the lower flue in the latter half of the carbonization where the temperature in the coal is 600 ° C or higher. ..