JP3171984B2 - Operating method of coke oven - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In the operation of a coke oven, when the coke is discharged (extruded) from the oven, the coke may become stuck in the oven and become completely immobile. This phenomenon is called a blockage and is one of the serious troubles that occur during the operation of the coke oven.

When the clogging occurs, a large load is applied to the furnace wall of the coke oven, which shortens the life of the coke oven, and the coke production as the furnace group decreases due to the interruption of the operation or the change of the charging schedule. In addition, the amount of heat consumed increases due to an increase in the placing time until extrusion can be performed, which leads to an increase in coke production cost.

Conventionally, such press-clogging has been controlled by the extrusion current of the extrusion ram when coke is extruded and the volatile content of the coal blend.

[0005] The extrusion current is a value measured when coke is extruded from a kiln, and the state where the extrusion current value exceeds a certain value and the extrusion ram stops is the compaction. Therefore, as a method of controlling the extrusion current, the extrusion current is recorded each time a certain coke oven is extruded, and if this value tends to increase, the next extrusion is performed by extending the setting time or adhering to the furnace wall. We are taking actions such as removing carbon and repairing furnace walls and hearths, and working to prevent clogging. However, the extrusion current is a value measured at the time of extrusion, and is not a material for judging whether or not extrusion is difficult before extruding coke. In other words, when there is a change in formulation or a change in operating conditions (for example, operating rate, moisture, etc.), there is no material for judging the extrudability, only the carbonization in an actual coke oven and the test to see if it can be actually extruded. .

[0006] The volatile matter of the coal blend is usually operated with a lower limit set for the volatile matter of the coal charged in the coke oven. However, if the volatile content is low, it cannot be said that the extrudability is poor, and it cannot be said that it is an effective management index.

Further, regarding the relationship between the displacement of coke in the height direction and the extrudability in a coke oven, it has been empirically found that if the total shrinkage (burn in the height direction) from the initial stage of carbonization is small, clogging is likely to occur. Was known. As for the displacement of the coke in the coke oven in the height direction, as shown in FIG. 1, the coke shrinks sharply until 2-3 hours after the start of the carbonization, but thereafter slightly shrinks or does not shrink at all. After 8 hours, a phenomenon that sudden contraction occurs again has been known (for example, C. Meyeret).
al. , Gluckauf-Forschungshe
fte, 42 (5) , 1981, 233-239).

[0008]

However, according to the above empirical findings, there is no correlation between the total shrinkage and the horizontal burnout that governs the coke extrusion property, so that it cannot be an optimal operation index. In addition, the phenomenon shown in FIG. 1 only indicates burnout in the coke height direction, and extrusion resistance, that is, burnout in the horizontal direction was unknown.

Further, the phenomenon of horizontal burnout is described in, for example, Mabushi et al .: Proceedings of the 78th Coke Special Meeting, (198)
5) p. 43, Arima et al .: CAMP-ISIJ, 5 (19
92), p. As shown at 54, the content is different for each researcher and there is no established theory at present.

[0010] It is an object of the present invention to provide a method of operating a coke oven which prevents a clogging and enables a stable operation.

[0011]

In order to solve the above-mentioned problem, the present invention measures the secondary shrinkage, which governs the extrudability of coke, by measuring the height of the coke layer twice at a fixed time during carbonization in a coke oven. By presuming and controlling the secondary shrinkage rate to a certain value or more, it is possible to prevent clogging by utilizing the effect that the coke horizontal burnout that affects extrusion resistance and the secondary shrinkage rate show a good correlation. It is characterized by. That is, the feature of the present invention is that in a coke oven,
At the start of the secondary shrinkage, the detachable disk-shaped plate provided at the lower part of the charging lid is pushed into the furnace by penetrating the rod from the upper part of the charging lid, and the rod when the disk-type plate reaches the surface of the coke layer. Measure the coke height from the indentation depth of the coke and measure the coke height before coke extrusion by the same method, and define it as the percentage of the ratio between the coke height displacement and the coal charging height expressed by the difference between the two. The method of operating a coke oven is characterized in that the coke is discharged from the oven after confirming that the secondary shrinkage rate is at least 2%.

Here, the start of secondary shrinkage is defined as the point in time at which the change in shrinkage rate per unit time exceeds 0.3% / hr after the middle stage of carbonization.

[0013]

Hereinafter, the present invention will be described in detail.

[0014] The inventors studied the temporal change of the displacement (shrinkage amount) in the height direction in the test furnace. After the coke height suddenly decreased (primary shrinkage) in the early stage of carbonization, the coke continued to hardly settle. It was confirmed that the contraction (secondary contraction) started again after the middle stage of carbonization. Further, when the time point at which the shrinkage rate change per unit time exceeds 0.3% / hr after the middle stage of the carbonization is defined as the start of the secondary shrinkage, the inventors assume that the coke height displacement from the start of the secondary shrinkage to before the extrusion. And the secondary shrinkage, expressed as a percentage of the coal charge height ratio, show a very good correlation with the horizontal burnout defined by the gap between the furnace wall and coke before extrusion,
The smaller the horizontal burnout, the greater the extrusion resistance,
They have found that jamming is also likely to occur. That is,
If the secondary shrinkage ratio, which has a good correlation with the horizontal burnout, is set to a certain value or more in order to set the horizontal burnout to a certain value or more, it is considered that extrusion resistance can be controlled and the clogging can be prevented. In addition, since the secondary shrinkage is determined by measuring the height of the surface after coking, the measurement error is small and it can be said that it is suitable for management.

The inventors measured the temporal change of the displacement in the height direction in an actual coke oven to determine the secondary shrinkage. As the secondary shrinkage increased, the extrusion resistance decreased and the secondary shrinkage decreased. When it was less than 2%, it was confirmed that compaction occurred. In actual operation, it takes much effort to measure the temporal change of displacement in the coke height direction during carbonization, so the coke height is measured at the start of secondary shrinkage and before leaving the kiln, and the secondary shrinkage rate is determined from the difference between the two. Should be obtained.

The present invention has been completed based on these findings.

Hereinafter, the present invention will be described specifically.

First, a method of measuring the coke height will be described. In the present invention, as shown in FIG. 2, a loading lid 1 provided with a detachable disk-shaped plate 2 at a lower portion is used, and a displacement measuring rod 4 is moved from the loading lid to the furnace through a hole 3 previously formed in the loading lid. Disk type plate 2
Is removed from the charging lid 1 and pushed into the furnace, and the coke height is measured from the pushing depth of the rod when the disk-shaped plate 2 reaches the coke layer surface 6. After the measurement, the bar is lifted up again to lift the disk-shaped plate, and the disk is attached to the lower portion of the charging lid. Then, the bar is taken out of the furnace, and the hole in which the bar is inserted is closed with a cap, thereby completing a series of operations.

Next, a method of determining the start of secondary contraction will be described. The time-dependent change pattern of the displacement in the height direction changes depending on the operating conditions (furnace temperature, moisture, charging density, coal blending, etc.). Therefore, each time the operating conditions change significantly, the start of secondary shrinkage is determined by the following method. There is a need to. In order to obtain the secondary shrinkage, first, a temporal change pattern of the height direction displacement is obtained. The displacement in the height direction is measured at intervals of 30 minutes to 60 minutes by the method described above. At this time, a temporal change pattern as shown in FIG. 1 is obtained. From FIG. 1, the time point at which the change in shrinkage rate per unit time exceeds 0.3% / hr after the middle stage of carbonization is determined by calculation, and this is defined as the start of secondary shrinkage under these operating conditions.

Alternatively, in a test furnace having the same furnace width, furnace wall brick, and heating structure as the coke oven, the time-dependent change pattern of the coke height direction displacement is measured under the same conditions as in the coke oven operation, and per unit time after the middle of carbonization. The change in shrinkage is 0.
The point in time exceeding 3% / hr is defined as the start of secondary contraction under these operating conditions.

The secondary shrinkage rate is determined from the thus determined secondary shrinkage starting time and the percentage of the ratio of the difference between the coke height before the coke extrusion and the coal charging height, and this value is 2% or more. After confirming that the coke is pushed out of the furnace, it is possible to avoid clogging.

[0022]

EXAMPLE In a coke oven having an oven height of 6 m, the temporal change of the coke displacement in the height direction was measured. The operating rate at this time is 1
The volatile content of the charged coal was 26.6%. As shown in FIG. 1, it shrinks sharply until 2-3 hours after the start of carbonization, but it continues to shrink slightly or not at all thereafter, and after 7-8 hours, sharp shrinkage starts again. . From FIG. 1, the start of the secondary contraction was found to be 8 hours later.

Then, after 8 hours and before leaving the kiln, the coke height was measured, and the secondary shrinkage was determined from the coke displacement at these two points. When the secondary shrinkage was 2% or more, no compaction occurred, and when it was less than 2%, compaction occurred. Therefore, when the secondary shrinkage was less than 2%, the placing time was extended to secure a secondary shrinkage of 2% or more. As a result, there was almost no trouble in extrusion, and stable operation was realized. .

[0024]

According to the present invention, it is possible to prevent clogging in a coke oven. As a result, stable operation can be achieved, and furnace wall damage due to blockage can be avoided to reduce furnace wall repair costs and extend furnace life, which has a great economic effect.

[Brief description of the drawings]

FIG. 1 is a diagram showing a temporal change of a coke displacement in a furnace height direction.

FIG. 2 is a diagram showing a method for measuring a coke height.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Loading lid 2 ... Disc type plate 3 ... Measuring rod insertion hole 4 ... Displacement measuring rod 5 ... Carbonization chamber 6 ... Coke layer surface

Continuation of the front page (56) References JP-A-3-273091 (JP, A) JP-A-2-235989 (JP, A) JP-A 4-106342 (JP, U) JP-A 61-199541 (JP) , U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10B 57/00 C10B 41/00

Claims (1)

(57) [Claims] 1. In a coke oven, at the start of secondary shrinkage, a removable disk-shaped plate provided at the lower part of the charging lid is pushed into the furnace by penetrating a rod from the upper part of the charging lid, and the disk-shaped plate is The coke height was measured from the pushing depth of the rod when it reached the surface of the coke layer, and the coke height before coke extrusion was measured by the same method. A method for operating a coke oven, comprising: discharging coke from a furnace after confirming that a secondary shrinkage rate defined by a percentage of an input height ratio is 2% or more.