JPH07278562A - Operation of coke oven - Google Patents

Abstract

PURPOSE:To prevent the compression packing of coal and the damage to furnace wall, reduce the mending cost and prolong the furnace life and enable stable operation of a coke oven by controlling the maximum swelling pressure of a coke oven in the carbonization of coal to a specific level according to the furnace height. CONSTITUTION:A coke oven is stably operated by estimating the maximum swelling pressure (P) in carbonization stage from the relationship of the formula I [20(%) <=VM<=38(%); 15(%)<=Ti50(%)] herein VM is the amount of volatile matter of coal and TI is the amount of inert component, compounding one or more kinds of coals in such a manner as to keep the sum of the maximum swelling pressure in carbonization (SIGMAP) below a permissible limit by calculating the pressure from the relationship of the formula II (N is integer of the kinds of coal; fi is weight of i-th coal based on total weight of coal ; Pi is maximum swelling pressure at carbonization of the i-th coal) taking advantage of the additivity of the swelling pressure in the compounding of coal, and controlling the maximum swelling pressure in the carbonization of coal to <=7TkPa for an oven having a furnace height of >=6m and to <=10kPa for an oven having a furnace height of <6m.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a coke oven.

[0002]

2. Description of the Related Art In a coke oven, when the maximum expansion pressure during coal carbonization increases, the coke grain size tends to decrease and the gap between the oven wall and the coke tends to narrow. Both of these phenomena increase the pressure measurement during coke extrusion (pressure applied to the heating wall in the carbonization chamber during coke extrusion), and as a result, the frictional force between the coke and the furnace wall increases,
Extrusion resistance increases.

In the operation of a coke oven, when the coke is discharged (extruded) from the oven, the coke sometimes becomes stuck in the oven and becomes completely immobile. This phenomenon is called “clogged” and is one of the serious troubles that occur during coke oven operation.

When this clogging occurs, a large load is applied to the furnace wall of the coke oven, the life of the coke oven is shortened, and the production of coke as a furnace group is reduced due to interruption of operation and change of the charging schedule. However, the amount of heat consumed also increases due to the increase in the placement time until it can be extruded,
This leads to an increase in coke manufacturing costs.

Conventionally, this clogging has been controlled by the extrusion current of the extrusion ram for extruding the coke and the volatile content of the coal blend.

Regarding the extrusion current, when the extrusion current tends to increase and the extrusion resistance tends to increase, the placing time is extended, and for the kiln with a large extrusion current, the carbon adhering to the furnace wall is removed and the furnace wall / bottom bottom is repaired. I have taken actions such as taking actions to prevent the jam. Although this control method is effective, it is clear that the action goes to the back and the back, and when, for example, a rapid composition change or a change in operating conditions (for example, operating rate, moisture, etc.) occurs,
There was no material to judge the extrudability, and it was only dry distillation in a coke oven to judge whether it could be extruded.

Regarding the volatile content of the blended coal, the lower limit of the volatile content of the coke oven charging coal is usually set and the operation is carried out. However, if it is more than the lower limit, it cannot be said that there is no problem in extrusion, and it cannot be said to be an effective management index.

A method of controlling the expansion pressure by blending coal has been proposed in Japanese Patent Application Laid-Open No. 04-306294. The method estimates the expansion pressure from the amount of inert components and the degree of coalification represented by the volatile content, carbon content, average reflectance, etc. of the coal, and conversely adjusts the coal composition based on this estimation method. Then, the expansion pressure is controlled within an appropriate range below the control value by setting the degree of coalification and the amount of inert components within appropriate ranges. However, the purpose of the method is to control the expansion pressure for preventing damage to the furnace wall of the coke oven, and therefore the object and control values are different from those of the present invention.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coke oven operating method which prevents clogging and enables stable operation.

[0010]

The feature of the present invention is that the relational expression of the volatile matter (VM) of the coal, the amount of the inert component (TI) and the maximum expansion pressure (P) log (P / kPa) =
-0.143 x (VM /%) -0.083 x (TI /
%) + 7.364 ... (1) is used to estimate the maximum expansion pressure from the volatile content and the amount of the inert component, and the maximum expansion pressure is determined by blending the charged coal so that the maximum expansion pressure is 6 m or more. Is controlled to 7 kPa or less and to 10 kPa or less for a furnace having a furnace height of less than 6 m, which is a coke oven operating method.

That is, the gist of the present invention is that in the method of operating a coke oven, the maximum expansion pressure during coal carbonization is controlled to 7 kPa or less in a furnace having a height of 6 m or more, and 10 kPa or less in a furnace having a height of less than 6 m. A method of operating a coke oven, characterized by:

Volatile content (VM) and amount of inactive components (T) of coal
From I), the maximum expansion pressure (P) during dry distillation is estimated from the relationship of the following formula (1), and it is calculated from one or more kinds of coal based on the relationship of the following formula (2) based on the additivity in coal blending of the expansion pressure. The method for operating a coke oven according to claim 1, wherein the composition of one or more kinds of coal is adjusted so that the sum ΣP of the maximum expansion pressures during dry distillation is equal to or less than the allowable limit value.

Log (P / kPa) = − 0.143 × (VM /%) − 0.083 × (TI /%) + 7.364 (1) Here, 20 (%) ≦ VM ≦ 38 (%) , 15 (%) ≦
TI ≤ 50 (%)

[0014]

[Equation 2]

Here, N: integer, type of coal fi: weight of i-th coal with respect to total coal weight Pi: maximum expansion pressure during dry distillation of i-th coal, maximum expansion during dry distillation from the relationship of the following formula (1) The pressure (P) is estimated, and the sum ΣP of the maximum expansion pressure during carbonization calculated from one or more types of coal based on the additivity of the expansion pressure in the coal blending from the relationship of the following formula (2) becomes less than or equal to the allowable limit value. The method of operating a coke oven according to claim 1, wherein the blending of one or more kinds of coal is adjusted.

[0016]

When the inventors obtained the relationship between the maximum expansion pressure during coal carbonization and the extrusion current in the actual furnace, it was confirmed that the higher the maximum expansion pressure during coal carbonization, the greater the extrusion current. We thought that by controlling the maximum expansion pressure during coal carbonization to a certain value or less by blending the charged coal, it is possible to control the extrusion resistance and prevent clogging.

Here, the correlation between the maximum expansion pressure during coal carbonization and the maximum extrusion current value differs depending on the height of the furnace. Even if the maximum expansion pressure during coal carbonization is the same, the maximum extrusion current value increases as the furnace height increases. Was confirmed to be large. Therefore, it is necessary to distinguish the control value according to the target furnace height. According to actual equipment tests, the control upper limit value is 7 kPa for furnaces with a furnace height of 6 m or more, and the control upper limit value is 10 kPa for furnaces less than 6 m.
It turns out that

The maximum expansion pressure control method during dry distillation by adjusting the coal composition will be described below.

As a result of studying the influence of coal properties on the expansion pressure (P), the present inventors have found that the expansion pressure is governed by the volatile matter (VM) and the amount of the inert component (TI). It was In addition to the volatile content, the amount of the inactive component affects the expansion pressure.Since the inactive component does not soften and melt during carbonization, the generated gas easily escapes from the interface with the active component, which causes the expansion pressure. It is considered that the gas pressure in the molten coal layer is likely to decrease. Then, as shown in FIG. 1, as a result of measuring the expansion pressure of various coals having different amounts of volatile components and inert components, 20 (%) ≦ VM ≦ 38 (%), 1
It was found that the formula (1) can be arranged in the region of 5 (%) ≦ TI ≦ 50 (%).

From the equation (1), the expansion pressure can be controlled so as to be equal to or lower than the predetermined limit value by adjusting the volatile content and the amount of the inert component. That is, since the expansion pressure can be estimated from the volatile content and the amount of the inert component, conversely,
Based on this estimation method and the formula (2) of additivity of maximum expansion pressure and coal composition, the expansion pressure is controlled by adjusting the composition of coal to bring the volatile content and the amount of the inert component into proper ranges. It is possible to control within an appropriate range below the value.

[0021]

[Example] In a coke oven having a furnace width of 450 mm, a furnace length of 15.7 m and a furnace height of 6.5 m, the correlation between the maximum expansion pressure during coal carbonization and the extrusion resistance was investigated.

The maximum expansion pressure was estimated from the volatile content of coal and the amount of inactive components according to equation (1).

For the extrusion resistance, the maximum extrusion current value of the extrusion ram during extrusion was used as an index.

According to this expansion pressure estimation method, the maximum expansion pressure of coal having the composition shown in Table 1 was estimated to be 6.1 kPa, the maximum extrusion current value during the carbonization of coal was 360 A, and no clogging occurred.

The maximum expansion pressure of coal having the composition shown in Table 2 is 7.9 kPa, and the extrusion current during the carbon dry distillation exceeds 390 A, which is the set value for clogging in conventional operation, and increases to about 430 A. , Clogged up.

[0026]

[Table 1]

[0027]

[Table 2]

As shown in FIG. 2, with respect to coal having a maximum expansion pressure of 7 kPa or less, the extrusion current value increases with the expansion pressure, but it has not reached the clog. On the other hand, in the case of coal having a maximum expansion pressure of 8 kPa, clogging occurred.

In the conventional operation, the set value of the maximum extrusion current value, which is the clogging, is 390A. Therefore, from the relationship of Fig. 2, the control value of the maximum expansion pressure during coal carbonization should be 7 kP.
By defining the pressure as a and controlling the expansion pressure to be equal to or lower than the expansion pressure, almost no trouble in extrusion was eliminated, and stable operation was realized.

[0030]

According to the present invention, it is possible to prevent clogging in a real coke oven. This enables stable operation, avoids damage to the furnace wall due to clogging, reduces furnace wall repair costs, and extends furnace life, which has a large economic effect.

[Brief description of drawings]

FIG. 1 is a graph showing the correlation between the volatile content and the amount of inert components of coal and the expansion pressure.

FIG. 2 is a diagram showing the relationship between the maximum expansion pressure during coal carbonization and the maximum extrusion current value.

Claims (2)

[Claims] 1. A coke oven operating method, wherein the maximum expansion pressure during coal carbonization is 7 k in a furnace having a furnace height of 6 m or more.
A method for operating a coke oven, which is characterized by controlling to 10 kPa or less in a furnace of Pa or less and less than 6 m. 2. The maximum expansion pressure during dry distillation (P) is estimated from the relationship of the following formula (1) from the volatile matter (VM) of coal and the amount of inactive component (TI), and the expansion pressure is applied in coal blending. It is characterized in that the composition of one or more coals is adjusted so that the sum ΣP of the maximum expansion pressures during carbonization calculated from the one or more coals based on the following formula (2) is below the allowable limit value. The method for operating a coke oven according to claim 1. log (P / kPa) = − 0.143 × (VM /%) − 0.083 × (TI /%) + 7.364 (1) Here, 20 (%) ≦ VM ≦ 38 (%), 15 ( %) ≤
TI ≦ 50 (%) [Equation 1] Here, N: integer, kind of coal fi: weight of i-th coal with respect to total coal weight Pi: maximum expansion pressure during carbonization of i-th coal