JPH11131074A - Operation of coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for operating a coke oven to equalize the carbonization times all over the coke oven and to prevent improper carbonization, by reducing within a definite range a quantity of coal to be charged to a carbonization chamber where an operating cycle time (from the initiation of heatup to the completion of generating gases) was behind the set point. SOLUTION: The method comprises reducing a quantity of coal to be charged to a carbonization chamber where an operating cycle time (i.e., time required from the initiation of heatup to the completion of generating gases) was Δt (h.) behind the set operating cycle time ts (h.) by a quantity of at least (δt/ts )×100 (%) and that within a quantity of <=20% of the normal quantity of coal to be charged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of operating a coke oven, and more particularly to an operation method of a coke oven capable of preventing extrusion of poorly carbonized coke.

[0002]

2. Description of the Related Art There are various types of coke ovens depending on the method of supplying fuel and air, the arrangement of heat storage chambers, and the structure of combustion chambers and the like. Generally, a lower part is provided with a heat storage chamber, and an upper part is provided with a combustion chamber and a carbonization chamber which are arranged alternately. Powdered raw coal is charged into the coking chamber, the fuel gas and air are preheated in the regenerator, burned in the combustion chamber, and the combustion heat is transferred to the adjacent coking chamber to remove the coal in the room. Carbonize. When the coal in the coking chamber is heated while shutting off the air, it releases moisture, occluded CO, CH _4, etc. as the temperature rises, and when it exceeds 300 ° C., thermal decomposition of the coal itself starts and gas and chemical Water and tar are rapidly generated and soften and melt. Then, when the temperature becomes close to 500 ° C., it solidifies again to form a porous mass semi-coke. When the temperature further rises to 900 ° C. or higher, the release of volatile components is almost complete, and high-temperature carbonized coke is obtained. The time required from the start of the heating to the end of the gas generation is referred to as a burn-out time. The coal carbonization in the furnace should end after the burn-down time, but in fact, the progress of the carbonization near the furnace lid is partially delayed, so that coke is not completely formed. Therefore, after an additional time of about 1 to several hours for aging and soaking (referred to as an installation time), the material is extruded from the carbonization chamber. The sum of the placing time and the fire-out time is called a carbonization time, and this is an extrusion cycle.

[0003] If the carbonization is extruded in an incomplete state without an appropriate burn-off time, the remaining volatiles are incompletely burned in contact with the air and soot (black smoke) is emitted. .
On the other hand, if the carbonization is excessive, there is a problem that excessive energy is wasted and economic loss is caused. Generally, the length of the required burn-off time depends on the properties of the coal itself, the dry density conditions such as the charging density, heating rate, and final temperature of each carbonization chamber, and the individual carbonization chambers (such as the amount of carbon adhering). It is also affected by the condition of the kiln, etc., causing variations between the carbonization chambers.

[0004] The point of operating a coke oven is to ensure the uniformity of the carbonization time for each kiln, and it is important to take measures against variations in the burn-out time between the kilns of the furnace. For that purpose, it is essential to grasp the burn-out time and the furnace temperature in each carbonization chamber. Regarding the burn-out time, a method was adopted in which the furnace was opened after carbonization in the actual operation, the state was observed, the suitability of the burn-off time set for this treatment was confirmed, and this was reflected in the next treatment. I have.

[0005] In a normal coke oven coke oven, heat required for carbonization is transferred from both sides to a coal bed in the coking chamber through a furnace wall brick interposed between the combustion chamber and the coking chamber. That is, the fire fall in carbonization is heat transfer rate-limiting,
Basically, it is determined by the temperature of the furnace wall. Therefore, in order to keep the burn-out time at a predetermined value, the furnace temperature is grasped and the amount of combustion gas supplied to the combustion chamber is adjusted. For this reason, various temperature measuring methods have been proposed.

[0006]

However, there is an unsolved problem that if a temperature sensor is installed in each of several tens of carbonization chambers for grasping the temperature, an enormous cost will be required.

Further, even if the burn-down time and the furnace temperature are grasped for each coking chamber and the distribution state of the coking chambers in which the carbonization is defective is detected in advance, all of the carbonization chambers in which the carbonization is defective are extruded from the coking chamber. It is actually difficult to avoid completely. Because, for the carbonization chamber which became poor carbonization,
By taking a longer burn-down time than the other carbonization chambers (the same setting time is required), a sufficient dry distillation state can be obtained,
In that case, the extrusion cycle becomes longer than the set value, resulting in a so-called flying kiln deviating from the planned extrusion cycle of the entire furnace. When this flying kiln comes out, the movement of the coal-charging truck, the extruder, the guide truck, etc., which are the auxiliary equipment of the coke oven, becomes irregular and discontinuous. This makes it easier to mischarge coal when charging it into the coking chamber for the next cycle, which not only reduces the production volume, but also reduces the risk of coal scattering and dusting on the furnace upper surface. There is an unsolved problem.

[0008] Even if the combustion gas amount is adjusted by grasping the furnace temperature and the burnout time, it takes a long time to respond due to the large heat capacity of the coke oven. Therefore, it is necessary to repeat the feedback cycle process several times, in which the adjustment effect in the processing cycle is checked by checking the coke extruded after the process is completed, and further adjustment is performed in the next processing cycle in consideration of the result. However, there is an unsolved problem that poor carbonization is inevitable.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem in a conventional coke oven, and reduces the amount of coal charged to a coking chamber whose burn-out time is later than a set value within a certain range. Accordingly, it is an object of the present invention to provide a method of operating a coke oven in which the carbonization time of the entire furnace is made uniform and a subsequent carbonization failure is prevented.

[0010]

In order to achieve the above object, a method of operating a coke oven according to the present invention comprises:
When the carbonization is carried out with a normal coal charge, the set fire time t
_The amount of coal charged to the coking chamber where the fire was delayed by Δt (hr) with respect to _S (hr) is set to (Δt / t)
_S ) × 100 (%) or more.

In the method for operating a coke oven according to the first aspect of the present invention, the degree of decrease in the amount of coal charged into the coking chamber where the fire has been delayed is limited to a maximum of 20% of the normal amount of coal charged. Is good. This is because even if the amount of coal is reduced by more than 20%, the shortening rate of the burn-down time is saturated and the effect is not recognized.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are schematic views showing an example of a coke oven to which the present invention can be suitably applied. FIG. 1 is a perspective view, FIG. 2 is a sectional view taken along line II-II, and FIG.
It is II sectional drawing. The illustrated one is a Carl still coke oven, in which a number of heat storage chambers 1 are installed adjacent to each other at the lower part of the furnace body, and a combustion chamber 2 and a carbonization chamber 3 are alternately provided above each heat storage chamber. About 100 chambers are arranged in the furnace length direction. The heat storage chamber 1 is divided into two parts by a heat storage brick 4, and the combustion chamber 2 is divided into two parts by a flow straightening plate (duct) 5. After being preheated in the heat storage chamber 1, the fuel gas and the air are supplied to the combustion chamber 2 from the opening 5 a provided in the flow straightening plate 5 and burned in six stages. Therefore, the difference between the upper and lower temperatures is small. The gas after combustion passes through the adjacent heat storage chamber 1 and is recovered by the heat storage brick 4 and then discharged through the flue gas 7. The heat of combustion in the combustion chamber 2 is transferred to the coal bed in the coking chamber 3 through the furnace wall brick 6 and heats it. The heat storage brick 4 and the rectifying plate 5 heat the combustion chambers 2 as uniformly as possible. However, in practice, the ends of the furnace lids 9 and 10 are less likely to heat up. When the temperature is 1000 ° C., both ends are about 800 ° C.

[0013] As ancillary equipment of the coke oven, coal loaded from coal tower 12 is fed into each coking chamber 3 through charging inlet 3a, coal loading truck 13; extruder 14 for extruding coke in coking chamber 3 to the outside; A coke guide vehicle 15 that receives the extruded coke and drops the coke, and the coke guide vehicle 1
A digestion train 16 for transporting the red hot coke dropped from 5 to a digester for waste heat recovery is provided.

In the operation of the coke oven, coal is initially charged into each coking chamber 3 with the amount of coal charged in a normal operation. The amount is the same for each carbonization chamber 3. Taking into account the various factors affecting the burn-down time described above, a burn-down time t _S (hr) corresponding to the amount of coal charged is set.
The extrusion cycle is defined as the carbonization time obtained by adding the two-hour storage time. Then, the fuel gas is supplied to the combustion chamber 2 at a predetermined flow rate and burned, and the coal layer in the carbonization chamber 3 is heated. When the extrusion cycle time has elapsed, the heating is stopped and the furnace lids 9 and 10 are opened. At this time, the coke in the carbonization chamber 3 which was still insufficiently carbonized can be discriminated because the remaining volatile components incompletely burn in contact with air to emit soot (dust generation). Is determined.

The carbonization chamber 3 having poor carbonization is heated again by closing the furnace lids 9 and 10. Heat until no dust is observed,
If the required reheating time Δt (hr) is obtained, the time is the time required for the fire to be delayed, in other words, the time required for the fire to be reduced. Next, the coke in the coking chamber 3 of the coke oven 1 is discharged out of the oven by the extruder 14. This extrusion operation is repeated while sequentially moving the extruder 14. After discharging, coal is charged in the next cycle. At this time, the amount of coal charged to the carbonization chamber 3 determined to be poor in carbonization is reduced. The degree of the weight reduction (coal charge reduction rate) is determined by the set fire time t in the previous cycle in which the carbonization was performed using the normal coal charge.
_At least the same ratio as the ratio of the burnout delay time Δt (hr) to _S (hr) (the burnout time reduction ratio). That is, the _{(Δt / t S) × 100} (%) or more weight loss.

Due to the reduction in the amount of coal charged, the amount of heat received per unit coal increases in the carbonization chamber 3 in which the carbonization was poor in the previous cycle, the burn-out time was shortened from the previous time, and the portion where carbonization was delayed was reduced. Coke is promoted.
For this reason, it is possible to reliably prevent coke extrusion in the poor carbonization chamber without disturbing the extrusion plan.

However, according to the test results in the actual furnace shown in FIG. 4, the effect of reducing the amount of coal charged to shorten the burnout time is not always linear. That is, the relationship with the burn-down time reduction rate is substantially linear when the coal loading is 20% or less, but the burn-down time reduction rate is saturated when the coal loading exceeds 20%,
It's not a good idea. Therefore, the upper limit of the coal loading reduction rate in the present invention is preferably set to 20%.

Further, the value of the burnout time reduction rate corresponding to the value of the coal charge reduction rate is smaller. For example, the reduction rate of fire time is 13%, 7%, and 3.5%, respectively, while the reduction rate of coal quantity is 20%, 10%, and 5%.
Approximately 1.5 times the reduction rate of fire time is the reduction rate of coal charge. Therefore, the target burnout time reduction rate Δ
In order to achieve t / t _S , it is preferable to set the coal reduction rate to a value that is 1.5 times the value.

Thus, according to the present invention, the risk of carbonization failure is eliminated by reducing the amount of carbonization in advance in the carbonization chambers which tend to be carbonized out of a large number of carbonization chambers of the coke oven. To continue operations. As a result, there is room for steady adjustment of the combustion gas amount during that time, and after the completion of the gas amount adjustment, the normal coal charge amount is returned.

(Examples) The effects of the present invention will be described below with reference to examples. An experiment was conducted with a normal furnace loading of 30.5 drytons / kiln per room (kiln) using a carstill still type furnace having a height of 6 m. 130% daily occupancy rate
(Extrusion cycle = fire fall time + placement time = 24 hr /
130 × 100 = 18.5 hr). The breakdown is
The burn-out time was 16.5 hr and the placing time was 2 hr. When treated under these conditions, there were 25 carbonized chambers that exceeded the set burn-out time of 16.5 hr, out of a total of 102 chambers, and as shown in Table 1, about half of them were found to have generated dust during extrusion by visual judgment. Was done.

[0021]

[Table 1]

Therefore, the amount of coal charged to these dust generating chambers was reduced as follows. Set fire time t _S : 16.5 hr Fire time delay time Δt: 0.8 hr Therefore, fire time shortening rate Δt / t _S × 100 = 4.8% We assume reduction rate.

When the operation of the coke oven was performed again while reducing the amount of coal charged in the dusting carbonization chamber, the number of carbonization chambers in which the burn-out time exceeded the set value of 16.5 hr was reduced by half. In particular, 1
Nothing exceeded hr or more. As a result, dust generation during extrusion was reduced to zero, and the operation could be performed without disturbing the original extrusion plan.

On the other hand, as a comparative example, the same furnace as in the above example was used. Immediately after the end of the example, the normal coal loading (30.5 dryton / kiln) was returned to the entire coking chamber, and the usual method was followed. The operation was continued for three days. Thereafter, and it reduced the Sosumi amount for dusting coking chamber as Sosumi reduction ratio of 0.5 times the fire fall time saving rate Δt / t _S (5 percent).

As a result, although the burnout time was shortened, about 80% of the carbonized chambers exceeded the set value of 16.5 hr, and in particular, 20% of the chambers exceeded 1 hr or more. Although dusting at the time of extrusion was also reduced, 1/4 remaining was still observed.

[0026]

As described above, according to the method of operating a coke oven according to the present invention, the amount of coal charged into the coking chamber where the fire has been delayed is reduced within a certain range. Therefore, the carbonization time of the entire furnace can be made uniform without installing an expensive temperature sensor, and the effect of preventing a skipping kiln and poor carbonization can be prevented.

Further, it is possible to prevent dust from being generated at the time of pushing out, which contributes to environmental protection. In addition, C gas which has been incompletely burned and exhaled at the time of extrusion can be recovered, which is also effective in energy saving.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a coke oven of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a diagram showing a relationship between a coal loading reduction rate and a fire-fall time reduction rate.

Claims (2)

[Claims] When the carbonization is carried out at a normal amount of coal, the amount of coal to be supplied to the carbonization chamber, which is delayed by Δt (hr) with respect to the set burn-out time t _S (hr), is calculated as the normal amount. A method for operating a coke oven, characterized in that at least (Δt / t _s ) × 100 (%) is reduced from the amount of coal charged. 2. The coke oven operating method according to claim 1, wherein the degree of decrease in the amount of coal charged into the coking chamber where the fire has been delayed is limited to a maximum of 20% of the normal amount of coal charged. Operating method.