METHOD OF ESTIMATING LOAD GENERATED WHEN COKE IS EXTRUDED
FROM COKE OVEN

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method of estimating a load generated when coke is extruded, for example, from a horizontal chamber type coke oven, especially in consideration of the characteristics of coke cakes that are determined by the kind of coal charge and carbonization conditions in the case where a furnace wall of a carbonization chamber has a projection portion formed therein.

This application claims priority from Japanese Patent Application No. 2008-279889, filed on October 30,2008, the content of which is incorporated herein by reference in its entirety.

Description of Related Art

In the operation of recent coke ovens, in order to achieve an improvement in coke quality and productivity, the charge (filling up) density of coal in a carbonization chamber tends to increase. Because of this, when the coke is extruded, the load acting on a side wall (furnace wall) of the carbonization chamber increases and consequently the extrusion load of the coke tends to increase.

In addition, because of increasing wear occurring in furnaces constructed 30 years ago, there are an increasing number of coke ovens in which the stiffness of the furnace walls has deteriorated. In such coke ovens, deformation or unevenness occurs on the furnace wall surfaces of the carbonization chambers thereof. While coke cakes pass over a place where such deformation or unevenness occurs, the coke extrusion resistance increases to heighten the load acting on the furnace wall. As a result, in the coke ovens, the occurrence of problems, such as fracture pores made through furnace wall bricks, damages to the furnace wall, and the like, is likely to increase.

More specifically, in the carbonization chamber of a coke oven of which wear has increased, projection portions (convex portions) may be formed due to the attachment of carbon on the furnace wall or recessed portions (concave portions) may be formed due to the loss of furnace wall bricks, and thus the level of unevenness of the furnace wall surface may increase. When the coke passes over the projection portion, a reaction force is applied from the inclined surface on the extrusion ram side of the projection portion, and the load corresponding to the reaction force acts on the furnace wall. On the other hand, when the coke passes over the recessed portion (concave portion), a reaction force is applied from the inclined surface on the side of a coke guide carrier of the recessed portion (concave portion), and the load corresponding to the reaction force acts on the furnace wall. If the load corresponding to the reaction forces acts on the furnace wall of which the stiffness has deteriorated, there is a risk that the furnace wall may be damaged.

In such circumstances, it becomes more important to prevent the furnace wall from being excessively loaded by evaluating in advance the force required to extrude the coke cakes after carbonization from the carbonization chamber and the load acting on the furnace wall.

The force required to extrude the coke cakes from the carbonization chamber of the coke oven is determined by the resistance when the coke cakes are moved. As two kinds of primary factors that determine the resistance, (i) a primary factor caused by the furnace body side and (ii) a primary factor caused by the characteristic of the coke cakes may be considered.

The "primary factor caused by the furnace body side" mainly refers to the characteristics of the furnace wall. Specifically, there may be the unevenness of furnace wall bricks, the roughness of furnace wall bricks, the friction coefficient between the furnace wall and the coke cakes, the strength of the furnace wall (the displacement of the furnace wall during extrusion), and the like.

Among these, it is considered that the greatest influence is from the unevenness of the furnace wall bricks. In particular, recently, there are many cases where, as the wear on the coke ovens increases, carbon attaches to the furnace walls and projection portions are formed thereon in the carbonization chambers of the coke ovens as described above. In portions where the projection portions of the carbon are formed, the furnace width (distance between furnace walls) is narrowed by what extent (narrow furnace width portions). When coke cakes pass over the narrow furnace width portions, a reaction force, which is applied from the inclined surface of the extruder side of the projection portions, acts on the coke cakes. Further, since the coke cakes pass over the portions that are narrower than the original width of the carbonization chambers, a more excessive force than usual is necessary. As described above, when the coke cakes pass over the projection portions, the resistance that occurs when the coke cakes are extruded is increased.

As disclosed in Japanese Unexamined Patent Application, First Publication No. H08-283730, the extrusion pressure of the coke cakes acts as a pressure that pushes against the furnace wall in exact accordance with the lateral pressure inversion rate that is determined by a gap (clearance) between the coke lumps and the furnace wall. In the case where a resistance force that is more excessive than usual, such as the reaction force applied from the inclined surface of the projection portions, the force required to pass over the narrow furnace width portions, and the like, occurs, excessive extrusion force is required to overcome the reaction force. Because of this, in accordance with the degree of the reaction force, a higher load (pressure) than the typical load acts on the furnace wall.

In this case, if the side load generated on the furnace wall of the carbonization chamber becomes higher than the stiffness of the furnace wall, the possibility of problems, such as fracture pores in the furnace wall bricks, damage to the furnace wall, and the like, occurring is extremely heightened. Accordingly, in order to prevent the occurrence of such problems, it is required to operate the coke furnace taking into consideration the influence of the projection portions formed on the furnace walls exerted on the extrusion load. For this, there is a need for the development of a method of predicting the extrusion load with good accuracy in cases where the projection portions are present on the furnace walls.

With respect to the influence of the projection portions, the inventors have found that a "resistance index", which is obtained by digitizing the shape and the existing position of each projection portion, corresponds closely to the extrusion force, and have filed a patent application (see Japanese Unexamined Patent Application, First Publication No. 2008-201993).

On the other hand, the "primary factor caused by the characteristic of the coke cakes" may refer to the strength of coke lumps, a horizontal burning reduction amount (rate), a gap amount (rate) in the coke cake, and the like.

The coal charged in the carbonization chamber in the carbonization process is shrunk in a furnace width direction after coal softening melting layer meet each other in the center in the furnace width direction, and a horizontal burning reduction occurs to reduce the volume in the horizontal direction. This horizontal burning reduction of the coke is closely related to the gap amount that is generated in the center in the furnace width direction of the coke and the gap amount (hereinafter, the sum of such gap amounts is called a "total gap amount in the furnace width direction") that is formed between the furnace wall and the coke lumps. In the case of extruding the coke cakes out of the carbonization chamber, a portion of the extrusion force (pressure) that is given from the extruder to the coke cakes is applied to the furnace wall surface as a lateral pressure (for example, see "Ironmaking Conference Proceedings" AIME, 1998, 1155-1159p). As the horizontal burning reduction amount becomes larger and the total gap in the furnace width direction becomes larger, the force that is required to extrude the coke cakes becomes smaller, and as a result, the load (pressure) acting on the furnace wall is reduced.

Because of this, for the purpose of preventing an excessive load (pressure) from acting on the furnace wall, techniques of estimating the horizontal burning reduction amount (rate) of the coke and adjusting the operation conditions such as the carbonization time so that the gap between the furnace wall of the carbonization chamber and the coke lumps is not to be below a predetermined value are disclosed in Japanese Unexamined Patent Application, First Publication No. H08-283730 and Japanese Unexamined Patent Application, First Publication No. 2000-290658.

Japanese Unexamined Patent Application, First Publication No. 2008-201993 discloses that an extrusion load inscribed closely by a resistance index that is defined from the situations (shape, existing position, and the like) of a projection portion of a furnace wall surface if the carbonization states of the coke cakes are the same. However, in the actual coke oven operation, since the amount of moisture of coal charge or the combustion chamber flue temperature is changed and the carbonization time that is caused by the equipment trouble of mobile equipment is changed, it is extremely difficult to equally maintain the carbonization state of the coke cakes. Particularly, in the wear deteriorated coke oven, there is a high possibility that the wear deterioration will occur even in the combustion chambers arranged on both sides of the carbonization chamber in the same manner. Because of this, the carbonization conditions of coal may differ in the respective coke ovens. In addition, the combustion chamber has a structure in which a plurality of gas supply ports and air supply ports are arranged in a line in the coke extrusion direction. Because of this, even in accordance with the deterioration states of the gas supply ports and the air supply ports, the carbonization conditions of coal may differ. That is, even in one coke oven, the carbonization conditions of coal may differ.

Japanese Unexamined Patent Application, First Publication No. 2000-290658 takes into consideration the thickness of carbon that attached to furnace walls. However, it does not take into consideration the projection portions of the furnace walls caused by the attached carbon.

SUMMARY OF THE INVENTION

As described above, the influence of the primary factor on the furnace body side with respect to the coke extrusion force is related to the above-described resistance index. However, for the case where the primary factor on the coke cake side simultaneously has an influence, a clear index is not disclosed. In the case where the carbonization conditions of coal changed due to the primary factor on the furnace body side, the primary factor on the coke cake side may be changed, and thus even in the case of estimating the extrusion force using the resistance index as described in Japanese Unexamined Patent Application, First Publication No. 2008-201993, there may be a problem in the estimation accuracy. In the related art, although the gap between the furnace wall and the coke lump is watched, the actual gap amount is in the range of about several mm, whereas the gap amount in the center along the furnace width direction of the coke becomes in the range of several tens of mm. Accordingly, in order to estimate the extrusion force with good accuracy, it is necessary to also examine the influence of the gap amount in the center in the furnace width direction of the coke that is exerted on the extrusion force of the coke.

It is an object of the present invention to more improve the estimation accuracy of the coke extrusion load by presenting an index that has a good corresponding relationship with the extrusion force on the condition that the influences of both the characteristics of coke cakes, that are determined by the kind of coal charge and carbonization conditions and the primary factor on the furnace body side are included.

It is considered that the extrusion force, when the coke cakes pass over the narrow furnace width portions in which the projection portions are formed and the furnace width is narrowed by that amount is dominated by the relationship between the thicknesses of the projection portions, the total amount of gaps in the furnace width direction (the total gap amount in the furnace width direction), and the distance between the furnace walls.

Accordingly, the inventors have found that the extrusion load when the coke cakes pass over the narrow furnace width portions can be inscribed by a specified index as a result of investigating the relationship between the thicknesses of the projection portions for the extrusion load, the total gap amount in the furnace width direction, and the distance between the furnace walls.

The gist of the present invention based on the above-described information is as follows.

(1) According to an aspect of the present invention, there is provided a method of estimating a load generated when a coke is extruded from a coke oven, the method comprising the steps of: evaluating an extrusion load when coke cakes pass over a narrow furnace width portion in which the distance between furnace walls is narrowed by a projection portion that exists on the furnace walls of a carbonization chamber of the coke oven, using parameters of an index Qn that is defined by the following equation (1) in consideration of the distance L between the furnace walls, the thickness h of the projection portion, and a total gap w in the furnace width direction; and considering the total gap w as a gap that is obtained by adding the gap between the furnace walls and the coke cakes on the left and right in the coke cake extrusion direction and a gap amount in the center portion of the coke cakes.

Qn = (h-w)/L ...(1) 1

(2) In the case of (1), it is preferable to repeatedly measuring of the extrusion
load under conditions in which the distance L between side walls, the thickness h which is different from that of the projection portion, and the total gap w in the width direction, while replacing a plurality of projection portions, using an extrusion load measuring test device which can mount the projection portions each having the thickness h of another projection portions on the side walls, and obtaining in advance the correlation X between the Qn calculated using the equation (1) as described in the case (1) and the actually measured extrusion load; calculating an index Qn1 related to the carbonization chamber of the coke oven from a thickness h1 of the projection portion on the furnace walls of the carbonization chamber of the coke oven, a total gap amount w1 in the furnace width direction, which is obtained from the kind of coal charge, and carbonization conditions, and a distance Li between the furnace walls, using the equation (1) as described in the case (1); and obtaining the extrusion load of the carbonization chamber of the coke oven based on the correlation X and the Qn1.

(3) In the case of (2), it is preferable that the thickness hi of the projection portion is calculated by integrating the profile information of the furnace walls.

(4) In the case of (2) or (3), it is preferable that the correlation X between the Qn and the measured extrusion load is obtained by applying a predetermined force in the opposite direction to the extrusion direction of the coke cakes when the coke cakes arranged in the extrusion load measuring test device are extruded.

(5) In the case of (2) or (3), it is preferable that the correlation X between the Qn and the actually extrusion load is obtained by applying the predetermined force from an upper portion of the coke cakes when the coke cakes arranged in the extrusion load measuring test device are extruded.

According to the method of estimating the coke extrusion load in the coke oven according to an embodiment of the invention, the estimation is performed in consideration of the primary factor on the furnace wall side that is the primary factor which gets involved in extruding the load of the coke cake and the primary factor on the coke cake side simultaneously. Because of this, the extrusion pressure (furnace wall lateral pressure) that acts on the coke extrusion force and the furnace wall, which corresponds to the state of the furnace wall, the kind of coal charge, and the carbonization conditions, can be estimated with good accuracy.

Because of this, the operation conditions of the coke oven and the characteristic of the coal charge can be managed so that the furnace wall lateral pressure that is estimated based on the coke extrusion load does not exceed the resist pressure limit of the furnace wall. As a result, troubles such as fracture pores made through furnace walls can be prevented. Also, since a portion where there is the fear that the fracture pores may be made through the furnace wall bricks can be estimated with good accuracy based on the profile information of the furnace wall, it is possible to accurately determine the priority of the repairing the furnace wall, and thus the improvement of the repair efficiency can be achieved.

As a result, the lifespan of the coke oven main body is lengthened, and the operation in the coke oven can be stably performed.

In addition, according to the present invention, the force that is required to extrude the coke can be estimated, and thus whether to extrude the coke can be determined in advance. Accordingly, the trouble such as extrusion of the coke is reduced, and thus the improvement of the productivity of coke can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of the relationship between Qn obtained by a coke extrusion load measurement test and a force (coke pressure-reaction force) required to move over the projection portion;

FIG 2 is a diagram illustrating an example of the relationship between Qn obtained by a coke extrusion load measurement test and a terrace surface pressing force;

FIG 3 is a diagram illustrating an example of the relationship between Qn obtained by a coke extrusion load measurement test and (the terrace surface pressing force/extrusion pressure);

FIG. 4 is a diagram illustrating an example of the relationship between Qn obtained by a coke extrusion load measurement test and the total gap amount w in the furnace width direction;

FIG. 5 A is a front view illustrating a coke extrusion load measurement device used in an embodiment of the invention;

FIG. 5B is a side view illustrating the coke extrusion load measurement device illustrated in FIG. 5A;

FIG. 5C is a view illustrating an example of the shape of a projection portion that is used in the coke extrusion load measurement device illustrated in FIG. 5A;

FIG. 6 is a diagram illustrating an example of the measurement result of an extrusion test using the coke extrusion load measurement device illustrated in FIGS. 5A to 5C; and

FIG. 7 is a diagram illustrating gaps regarding coke cakes in a carbonization chamber.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the case of extruding coke cakes after carbonization of coal from a carbonization chamber in which a projection portion that is caused by the attached carbon is formed on a furnace wall, for example, as illustrated in FIG 7, it is necessary that respective coke lumps constituting the coke cakes move over an inclined surface 21 on an extruder side of the projection portion 9 from the extruder side to a coke guide carrier side and pass (move) over a terrace surface 22.

If the distance between the terrace surface 22 of the projection portion 9 and the opposite furnace wall is shorter than the length in the furnace width direction of the coke cakes existing on the extruder side of the projection portion 9, a larger force than that in the case where the furnace wall surface is even is required to pass over the projection portion 9. It is considered that the force that is required to pass over the projection portion 9 is dominated by the thickness of the projection portion 9 in the furnace width direction (the thickness h of the projection portion), the sum of gap amounts in the furnace width direction (the total gap amount w in the furnace width direction), and the distance L between the furnace walls.

Accordingly, the inventors have investigated the relationship of the difference between the thickness h of the projection portion with respect to the extrusion load and the total gap amount w in the furnace width direction by a coke extrusion measurement test using an extrusion load measurement test device to be described later. As a result, they have found that the force (extrusion force) that is required when coke cakes pass over the narrow furnace width portion in which the distance between the furnace walls is narrowed by the projection can be organized using an index Qn that is defined by the following equation (1).

Qn = (h-w)/L ...(1)

Here, the total gap amount w in the furnace width direction, as described later, is a value that is determined by the kind of coal charge, carbonization conditions, and the like. The total gap amount w in the furnace width direction, as illustrated in FIG 7, measures the total value of the amount of a gap 23 between the furnace wall 26 of the carbonization chamber and the coke lumps 25 (the sum of gap amounts on both sides of the carbonization chamber) and the amount of a gap 24 in the center in the furnace width direction of the coke cakes. In addition, h represents the thickness (in the furnace width direction) of the projection portion 9, and L represents the distance (furnace width) between the furnace walls 26 of the carbonization chamber.

In the equation (1), the reason why (h-w) is divided by the distance L between the furnace walls is to reflect the influence of the position of the carbonization chamber in the furnace length direction since the furnace width of the carbonization chamber has a tapered shape that is gradually widened from an extruder side (Pusher Side (PS)) to a coke guide carrier side (CS). In addition, since the width (average furnace width) of the carbonization chamber differs according to the coke oven, its influence is also considered. Due to this, Qn becomes a dimensionless number as a result.

The extrusion load measurement test was made using the extrusion load measurement test device (see FIGS. 5A to 5C) to be described later in a manner such that the projection portions 9 with various thicknesses were installed on a side wall of the extrusion load measurement test device, and an extrusion force and a reaction force that was opposite to the extrusion force were added to the coke cakes 2 to be tested by changing the gap amount between the side walls 5 on both sides and the coke lumps to be tested and the gap amount in the center of the coke lumps in the furnace width direction. The relationship between the force that is required to pass over the projection portions 9 (the value obtained by subtracting the reaction force from the coke pressure, that is, the force required to move over the projection portion) obtained from this experiment and the index Qn is illustrated in FIG 1. In addition, the relationship between the pressure (terrace surface pressing force) that acts on a terrace surface 22 of the projection portion 9 and the index Qn is illustrated in FIG. 2.

As illustrated in FIG. 1, the force that is required to move over the projection portion is approximated with a high correlation coefficient (R =0.87) by an exponential function using the index Qn indicated in the equation (1). In the same manner, the terrace surface pressing force can be approximated with a high correlation coefficient (R2=0.91) by an exponential function using the index Qn (see FIG. 2).

In addition, it can be understood that the ratio (the lateral pressure conversion ratio) of the terrace surface pressing force to the pressure (extrusion pressure) acting on the coke surface on the extrusion side is linearly changed with respect to the index Qn as illustrated in FIG. 3. This may be ascertained according to a Rankin factor from the viewpoint of a local terrace surface of the projection portion 9.

Although the relationship between the force required passing over the projection portion and the total gap amount w in the furnace width direction is illustrated in FIG. 4, a good corresponding relationship as illustrated in FIG. 1 is not obtained. From this, the validity of obtaining the correlation of the total gap amount w in the furnace width direction in consideration of the thickness h of the projection portion and the distance L between the furnace walls can be confirmed.

As described above, it can be known that the extrusion load (the force required to move over the projection portion, the terrace surface pressing force, and the lateral pressure conversion ratio) can be estimated with good accuracy by the equation using the index Qn which is determined in consideration of the primary factor on the coke cake side that is determined by the primary factor on the furnace main body side, the kind of coal charge, the carbonization conditions, and the like.

Next, a test device will be described, which is to obtain a method of obtaining the thickness h of the projection portion of the furnace wall of the carbonization chamber and the total gap amount w in the furnace width direction, which is required to estimate the coke extrusion force and the load that is applied to the side wall of the carbonization chamber when the extrusion force is set, and the relationship between the index Qn and the coke extrusion force.

The formation position and the thickness h of the projection portion that is formed on the furnace wall surface of the carbonization chamber can be obtained, for example, by actually measuring them with respect to the furnace wall surface of the carbonization chamber while moving a laser range finder as described in Japanese Unexamined Patent Application, First Publication No. 2005-249698.

Recently, with the wear of the coke oven, the importance of ascertaining the furnace wall state of the carbonization chamber is increasing. Due to this, the importance of investigating and measuring the state of the furnace wall bricks and the position and the shape of an uneven portion that is formed on the furnace wall by measuring the profile of the furnace wall with respect to the entire area in both the height direction and the oven length direction of the carbonization chamber is increasing. Devices for such investigation or measurement have been variously proposed in addition to that described in Japanese Unexamined Patent Application, First Publication No. 2005-249698. In the present invention, such known measures can be appropriately used when measuring the formation position, the thickness h, and the shape of the projection portion.

The total gap amount w in the furnace width direction, for example, may be obtained as follows.

The rate of shrinkage during the carbonization is changed according to the operation conditions, such as the brand and the mixing ratio of multiple caking coals that are mixed when manufacturing the coke and the carbonization time. In addition, since the carbonization chamber is generally in the form of a taper in the oven length direction, the burning temperature of the combustion chamber has a temperature distribution in the furnace to maintain constant heating of coal. Since the shrinkage rate is changed according to the temperature, it may be changed during the carbonization according to the position in the coke extrusion direction of the coke oven.

Accordingly, for example, as described in Japanese Unexamined Patent Application, First Publication No. H08-283730, a carbonization test may be performed using a test furnace (for example, having the size of the carbonization chamber in length 1050 mm x height 900 mm x width 450 mm) such as a small electric furnace, and on diverse coal charge conditions, the relationship between the carbonization time at various oven temperatures and the burning reduction amount is obtained in advance. From their relationship obtained in this test, the burning reduction amount (shrinkage rate) of the coke in the furnace width direction in the actual operation can be obtained.

In addition, the shrinkage rate can be obtained by the following method as described in Japanese Unexamined Patent Application, First Publication No. 2000-290658.

The shrinkage of the coke starts after the softening melting layer in the coke oven vanishes. At this time, the coke is shrunk toward the shrinkage center of the coke. Accordingly, the reduction in volume of the coke that is caused by the shrinkage is distributed to the reduction in volume caused by the shrinkage of the coke in the center portion of the carbonization chamber and the reduction in volume caused by the shrinkage of the coke on the furnace wall side.

The shrinkage rate (shrinkage coefficient) of the coke is mainly determined by the volatile component of coal and the temperature. For example, in C. Meyer, D. Habermehl and O. Abel: Gluckauf-Forshungshefte, 42(1981), 233, the shrinkage coefficient of the coke is indicated as a function of the volatile component of coal and the temperature. By providing the volatile component and the temperature based on the technique known to a person skilled in the art, the shrinkage rate of each portion of the coke layer can be obtained.

At this time, the temperature of each portion of the coke layer may be directly measured using a sheathed thermocouple or the like, or may be calculated through a one-dimensional heat conduction model, for example, using a known method as described in Tashiro et al., Fuzi Steel Technical Report, 17(1968), 353p.

As described above, after the coke shrinkage rate of each portion of the coke in the furnace width direction is obtained during the extrusion of the coke, the coke shrinkage amount on the furnace wall when a certain position in the furnace width direction of the carbonization chamber becomes the center of shrinkage is obtained based on the coke shrinkage rate of each portion. In addition, the average value of the coke shrinkage amount on the furnace wall, which is obtained in each shrinkage center position, is considered as the coke shrinkage amount on the furnace wall side.

For example, since the combustion chambers are arranged on both sides of the carbonization chamber, the proceeding of the carbonization in the coke oven is considered bilaterally symmetric in a state where the center portion in the furnace width direction in the carbonization chamber is set as a boundary. Accordingly, one half of the carbonization chamber is divided into 10 points in the furnace width direction, and the coke shrinkage amount on the furnace wall side is obtained with respect to 11 points including the 10 divided positions and both ends of the carbonization chamber when the respective positions become the shrinkage centers.

Then, the coke shrinkage amount on the furnace wall side and the gap amount between the furnace wall and the coke lumps can be obtained by obtaining an average value of the coke shrinkage amounts on the furnace wall side of the 11 points. In the same manner, the gap amount in the center along the furnace width direction can be obtained by obtaining an average value of the coke shrinkage amounts on the center side in the furnace width direction.

Then, as an offline test using the coke extrusion load measurement test device, a method of obtaining the coke extrusion force will be described wherein the projection portion having various thicknesses h and the load acting on the side wall surface, on the condition that the gap amount between the side wall and the coke lump and the gap amount in the center along the width direction are variously changed.

In the coke extrusion load measurement test device as illustrated in FIGS. 5A and 5B, a pair of side supports 7 and 7 (left and right sides with respect to the coke cake extrusion direction) are oppositely installed at a predetermined interval on a base 14.

In addition, in the front and the rear of the coke cakes in the extrusion direction, a pair of supports 15 and 16 is oppositely installed at a predetermined interval. A hydraulic cylinder 1 for extrusion is attached to one support 15, and a hydraulic cylinder 3 for adding a reaction force is attached to the other support 16.

Between the left and right side supports 7 and 7, pair of side panels 5 and 5, which correspond to the left and right side walls, are arranged. In addition, between the opposite hydraulic cylinder 1 for extrusion and the hydraulic cylinder 3 for adding the reaction force, a front panel 11 and a rear panel 12 (front and rear panels 11 and 12), which become movable walls, are arranged. Extrusion spaces of the coke cakes 2 for test are formed by the pairs of the side panels 5 and 5 and front and rear panels 11 and 12.

Rollers 20 are attached to a lower end portion of the front and rear panels 11 and 12 to smoothly move on the base 14. Accordingly, in the case of measuring the extrusion load and the reception side load to be described later, the friction between the front and rear panels 11 and 12 and the base 14 is reduced, and thus the accuracy of the obtained measurement result is improved.

The hydraulic cylinder 1 for extrusion transfers pressure to the front panel 11 by a cylinder head 10 at the front end of the rod thereof. In the same manner, the hydraulic cylinder 3 for adding the reaction force transfers a constant reaction force that is against the extrusion pressure to the rear panel 12.

In the case of extruding the coke cakes from the carbonization chamber in the actual coke oven, the force (extrusion pressure) that is transferred in the coke cakes is attenuated as it goes from the ES (Extruder Side) to the CS (Coke Side). In order to artificially realize the difference between extrusion pressures by the positions in the furnace length direction, the size of the reaction force by the hydraulic cylinder 3 for adding the reaction force is changed when the coke cakes 2 which are surrounded by the side panels 5 and 5 and the front and rear panels 11 and 12 is extruded using the hydraulic cylinder 1 for extrusion. Accordingly, the extrusion load measurement test can be performed on the condition that the existing position of the actually extruded coke cakes 2 in the length direction is optionally changed.

Between the cylinder head 10 of the hydraulic cylinder 1 for extrusion and the front panel 11, a load cell (a load converter) 17 is installed as a load detection measures. In the same manner, between the cylinder head 10 of the hydraulic cylinder 3 for adding the reaction force and the rear panel 12, a load cell (a load converter) 17 is installed as a load detection measures. By the respective load cells 17 and 17, the extrusion force of the hydraulic cylinder 1 for extrusion and the reception force received by the hydraulic cylinder 3 for adding the reaction force are detected.

In the actual coke oven, a gap (numeral 23 in FIG. 7) exists between the furnace wall surface and the coke lumps. In order to realize this condition, the side panels 5 and 5 are installed through intermediate movable walls 6 and 6 that are maintained by the hydraulic cylinders 4 and 4 for supporting the side panel so that they can be replaced in a direction that is perpendicular to the extrusion direction of the coke cakes.

The space between the side panels 5 and 5 and the coke cakes 2 in the direction that is perpendicular to the extrusion direction of the coke cakes 2 can be appropriately adjusted by moving the intermediate movable walls 6 and 6 by the hydraulic cylinders 4 and 4 for supporting the side panel based on the measurement values of the position detectors (for side surface) 8 and 8 installed in front and in the rear of the coke cakes 2 in the extrusion direction.

Between the intermediate movable walls 6 and 6 and the side panels 5 and 5, a plurality of load cells 18 and 18 for measuring the load acting on the side panels 5 and 5. The load (reception force) acting on the left and right side panels 5 and 5 can be detected as the total value of the values measured by the respective load cells 18.

The side panels 5 and 5 may move in the coke extrusion direction together with the coke cakes 2 during the coke extrusion. In order to prevent this, a movement restriction device such as a stopper or a linear motion guide may be attached to both end portions of the side panels 5 and 5 of the coke extrusion direction.

In order to evaluate the influence of the projection portion present on the furnace wall surface of the carbonization chamber of the coke oven exerted on the extrusion load, the recessed portion 9 as illustrated in FIG 5C is installed on a surface that is in contact with the coke cakes 2 of one side pattern 5, for example, by a fixing measures such as bolts and the like.

The shape of the projection portion 9 is installed to match the shape of the projection portion of the actual coke oven that is obtained by the above-described method. As an example thereof, a trapezoidal projection portion 9 having a wedge-shaped inclined surface formed on a portion thereof is illustrated in FIG. 5C. This projection portion 9 is composed of a terrace surface 22 that is parallel to the extrusion direction and an inclined surface 21 connected to the terrace surface 22. By performing respective tests using plural projection portions 9 having different thicknesses h of the projection portions 9, different lengths of the inclined surface 21 and the terrace surface 22, and different shapes and surface states of the projection portions 9, the influence of differences in the shape of the projection portions 9 exerted on the furnace wall load can be quantitatively evaluated.

In an example of FIG 5C, for example, the trapezoidal projection portion 9 having the wedge-shaped inclined surface 21 formed on a portion thereof is illustrated. However, the projection portion having the shape to match the actual coke oven, such as a curved inclined surface having the same curvature as a liquid droplet, an inclined surface in the form of a waveform, and the like, may be used. Even in this case, in the same manner as the trapezoidal projection portion 9 having the wedge-shaped inclined surface 21, the force that is required to move over the projection portion 9 may be approximated by a function using an index Qn.

In the actual coke oven, as described above, the self-load distribution exists in the height direction of the coke cakes. Because of this, as illustrated in FIG. 5B, by loading a weight 19 on an upper portion of the coke cake 2 as a load, the measurement can be performed in a state where the position of the projection portion 9 in the height direction of the carbonization chamber is changed. As the weight 19 loaded on the coke cake, for example, a steel plate may be used. By changing the thickness and the number of steel plates, the size of the load can be changed.

For example, a position detector 13 such as a laser range finder is attached to the hydraulic cylinder support 15 for extrusion that is installed on the base 14. The position detector 13 can successively measure the movement distance of the front panel 11 during the coke extrusion.

In the coke cake extrusion load measurement test device as constructed above, for example, a coke cake 2 for test of a predetermined size (for example, in length 600 mm x height 370 mm x width 430 mm), which is obtained through carbonization with a small electric carbonization furnace or the like, is arranged in a space that is surrounded by the side panels 5 and 5 and the front and rear panels 11 and 12 of the device. In this case, on one side of the side panel 5, a projection portion 9 with a predetermined condition (shape or the like that is detected in the actual coke oven) is prepared in advance, and then attached as illustrated in FIG. 5 A. In addition, the gap in the center portion of the coke cake 2 is measured.

The gap amount between the coke lump that forms the coke cake 2 arrange on the base 14 and the side panels 5 and 5 is adjusted to a predetermined value by moving the intermediate movable walls 6 and 6 based on the indication of the position detectors 8 and 8 installed in front and in the rear of the side supports 7 and 7. In addition, on the upper portion of the coke cake 2, the weight 19 that assumes the position of the projection portion 9 is loaded in the height direction of the carbonization chamber of the actual coke oven.

Next, the extrusion force is given to the coke cake 2 by operating the hydraulic cylinder 1 for extrusion, and the extrusion of the coke cake 2 starts by applying a predetermined reaction force thereto by the hydraulic cylinder 3 for adding the reaction force.

After the start of the extrusion, the coke cake 2 moves in the direction of the hydraulic cylinder 3 for adding the reaction force by the force of (extrusion force-reaction force), moves over the inclined surface 21 of the projection portion 9, finally moves over the terrace surface 22 of the projection portion 9.

When, the coke cake 2 passes over the projection portion 9, the extrusion force, reaction force, and the force acting on the left and right side panels 5 and 5 are successively measured by the load cells 17 and 18.

When the extrusion force acts on the coke cake 2 for test by the hydraulic cylinder 1 for extrusion, the hydraulic device of the hydraulic cylinder 3 is controlled so that the reaction force by the hydraulic cylinder 3 for adding the reaction force becomes constant. As described above, by changing the set value of the reaction force that is made constant (the extrusion force is also changed by the set value of the reaction force), the position of the coke cake 2 in the length direction can be changed in the actual coke oven, and thus the weight acting on the furnace wall at a certain position in the length direction of the furnace can be evaluated.

Also, as described above, by changing the amount of the weight 19 loaded on the upper portion of the coke cake 2, the position of the coke cake 2 in the height direction of the furnace in the actual coke oven can be changed, and thus the weight acting on the furnace wall at a certain position in the height direction of the furnace can be evaluated.

In the above-described order, a coke extrusion test was performed on the condition that indicated in Table 1. An example of a load profile during the extrusion that was obtained in this test is illustrated in FIG 6.

[Table 1]

As illustrated in FIG 6, after the extrusion of the coke cake 2 for test starts, the extrusion load and the reception side load were increased, and after the reception side load reached the set value (about 1.9 tonf) of the hydraulic cylinder 3 for adding the reaction force, the reception side load was maintained at almost a constant value.

After the movement distance of the cylinder head 10 on the side of the hydraulic cylinder 1 for extrusion reached 120 to 130 mm, the coke cake 2 for test started to move over the inclined surface 21 of the projection portion 9, and the left and right side surface loads started to increase.

If the extrusion proceeded further and the coke cake 2 intruded into a narrow furnace width portion composed of the terrace surface 22 of the projection portion 9 and the left side panel 5 in the extrusion direction, the extrusion load and the left and right side loads were further increased. At the time the extrusion distance (the movement distance of the hydraulic cylinder head for extrusion) was about 500 mm, almost the entire coke cake 2 was filled in the narrow furnace width portion, and the extrusion load and the left and right side loads became maximized. The reason why the respective loads deteriorated when the extrusion distance 500 mm was that the end of the coke cake 2 for testing started to be extruded from the coke extrusion load measurement test device.

The above-described coke extrusion test was performed changing the thickness h of the projection portion, the gap amount between the side wall (side panel) and the coke lump, and the gap amount in the center of the coke cake, and the extrusion load and the side load in the respective cases were measured. As a result, FIGS. 1 to 4 as above were obtained.

In FIGS. 1 to 4, the symbol "O" represents the result of a test that was performed under conditions where the initial value of the gap between the side wall and the coke lump was 5 mm (the total of both sides), the initial value of the gap in the center of the coke cake was 14 mm, and the thickness h of the projection portion was changed in the range of 0 to 50 mm. The symbol "A" represents the result of the test that was performed on the condition that the thickness h of the projection portion was maintained constant (30 mm), and the total gap amount w was changed in the width direction (between side panels). The symbol "□" represents the result of a test that was performed under conditions where the thickness h of the projection portion was maintained constant (30 mm), the initial value of the gap between the side wall and the coke cake was 0 mm (the total of both sides), and the gap amount in the center of the coke cake changed. The symbol "•" represents the result of the test that was performed under conditions where the thickness h of the projection portion was maintained constant (30 mm), the initial value of the gap amount in the center of the coke cake was set to 14 mm, and the gap between the side wall and the coke lump changed.

Further, if the above-described coke extrusion load measurement test is systematically performed by changing the reaction force by the cylinder 3 for adding the reaction force (reception side), and the load of the weight 19 loaded on the upper surface of the coke cake, the relationship among the index Qn, the extrusion force, terrace surface pressure, and the lateral pressure conversion rate, which correspond to the projection portion existing on various conditions can be obtained. In this case, although the extrusion load measurement test showed the result obtained in the cold process, the same result may be obtained even when the test is performed in the warming process.

As described above, according to the present invention, first, the relationship between the index Qn, the extrusion force (the force required to move over the projection portion), the terrace surface pressing force, and the lateral pressure conversion rate, as illustrated in FIGS. 1 to 3, is obtained in advance by the extrusion load measurement test.

Next, the position and the thickness hi of the projection portion that is formed on the furnace wall surface of the carbonization chamber of the actual coke oven, and the distance L1 between the furnace walls of a place where the projection portion is located are obtained, for example, by the measures as described in Japanese Unexamined Patent Application, First Publication No. 2005-249698. Further, the total gap w1 in the furnace width direction of the carbonization chamber of the place where the projection portion is located is calculated, for example, by the method described in Japanese Unexamined

Patent Application, First Publication No. 2000-290658.

Then, the index Qn1 is calculated for each projection portion on the furnace wall surface of the carbonization chamber from the thickness h1 of the projection portion of the actual coke oven, the distance L1 between the furnace walls, and the total gap w1 in the furnace width direction, which are obtained as described above. Then, based on the relationship between the index Qn obtained in advance, the extrusion force, the terrace surface pressing force, and the lateral pressure conversion rate, the extrusion force, the terrace surface pressing force, and the lateral pressure conversion rate are calculated for each projection portion existing on the furnace wall surface of the carbonization chamber from the calculated Qn1. In the present invention, since the indexes Qn and Qn1 are calculated in consideration of the gap amount of the coke cake in the center portion in the furnace width direction, the extrusion force, the terrace surface pressing force and the lateral pressure conversion rate can be estimated with good accuracy in comparison to that in the related art.

Based on the extrusion force obtained as described above, the force that is required to extrude the coke cake from the carbonization chamber of the actual coke oven is estimated. Specifically, for example, the force can be obtained by adding the extrusion force that is required when the coke cake passes over the narrow furnace width portion formed by the projection portion to the extrusion force at a time when no projection portion is on the furnace wall of the carbonization chamber and the furnace wall is in a healthy state as described above.

In addition, when a plurality of projection portions is present on the furnace wall, the total extrusion force that is required for the coke cake to move over the projection portions can be estimated with good accuracy by appropriately adding the extrusion forces required to pass over the projection portions. In the case where a plurality of projection portions are present, the number of projection portions that exert an influence on the extrusion of the coke cake is also changed according to the proceeding state of the extrusion of the coke cake. In the present invention, the force that is required to extrude the coke cake with respect to the projection portion can be estimated, and even in this case, the required extrusion force of the coke cake can be estimated with good accuracy.

In the related art, in the case where a plurality of projection portions exists on the furnace wall, there is no measure for evaluating the extrusion load with respect to the respective projection portions. By contrast, according to the present invention, since the extrusion load with respect to the respective projection portions can be estimated and evaluated with good accuracy as described above, it is possible to calculate the extrusion force that becomes necessary to move over the projection portions. Accordingly, diverse effects to be described later can be obtained.

According to the present invention, the index Qn is calculated in consideration of the total gap of the coke cake in the furnace width direction and the depth of the projection portion. Because of this, if the gas supply port or the air supply port of the combustion chamber is clogged due to the wear deterioration of the combustion chamber and the damage to the furnace wall to change the supply amount of gas or air, and the difference occurs in the carbonization of coal due to the change of the temperature distribution in the furnace, the extrusion force of the coke cake can be estimated with good accuracy.

If it is determined that the extrusion force that is required to extrude the coke cake from the carbonization chamber of the coke oven, which is estimated by the above-described method, exceeds the capability of the extruder (or a management value on operation), or the estimated value of pressing that acts on the terrace surfaces of the respective projection portions existing on the furnace surface exceeds the stiffness limit of the furnace wall on which the projection portions exist, for example, the total gap is estimated again on the condition that the carbonization time is extended in order to increase the gap between the furnace wall and the coke lump caused by the shrinkage of the coke cake in the furnace width direction. Then, based on the gap, the extrusion force or terrace surface pressure value is estimated, and the coke oven operation condition is managed so that the estimated value of the extrusion force that is required to extrude the coke cake is below the capability of the extruder (or a management value on operation) and the estimated value of the terrace surface pressing force is below the pressure-resistant limit of the furnace wall. Accordingly, an excessive extrusion force is prevented from being applied to the furnace wall, and thus damage to the furnace wall scarcely occurs.

If the estimated value of the coke extrusion force is close to the management value even in the case where the estimated value of the coke extrusion force does not exceed the capability of the extruder (or a management value on operation), a great force acts on the furnace wall, and this is not preferable. Even in such a case, according to the present invention, it is possible to perform adjustment and management so that the gap amount between the furnace wall and the coke lump and the gap amount of the coke cake in the center portion in the furnace width direction are extended by promptly changing the mixing conditions of the coal charge.

Also, according to the present invention, with respect to the place where the estimated value of pressing the terrace surface of the projection portion is high, in order to prevent problems such as fracture pores made through furnace wall bricks in advance, it is possible to promptly determine an accurate order for preferentially performing the repair operations, and thus the improvement of the repair efficiency can be achieved.

In addition, since the force that is required to extrude the coke can be estimated as described above, whether to extrude the coke can be determined in advance.

Accordingly, the trouble such as extrusion of the coke can be reduced.

As described above, according to the present invention, if there is a projection portion on the furnace wall surface of the carbonization chamber, the coke extrusion force, the terrace surface pressure, and the lateral pressure conversion rate can be estimated highly accurately, and the coke extrusion force and the furnace wall pressing can be reduced through performing the countermeasure on operation or repair operation based on the related information. As a result, the trouble on operation, such as extrusion of the coke, the fracture pores made through furnace wall bricks, the damage to the furnace wall, and the like, can be prevented. Accordingly, the lifespan of the furnace body can be lengthened, the coke production amount is increased due to the reduction of the operation trouble occurrence, and the operation load can be reduced since it is unnecessary to take the coke out of the carbonization chamber by manpower as the coke extrusion management.

According to the method of estimating the coke extrusion load in a coke oven according to the present invention, the trouble on operation, such as extrusion of the coke, the fracture pores made through furnace wall bricks, the damage to the furnace wall, and the like, can be prevented. Further, the lifespan of the furnace body can be lengthened, the coke production amount is increased due to the reduction of the operation trouble occurrence, and the operation load can be reduced.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

What is claimed is:

1. A method of estimating a load generated when a coke is extruded from a coke oven, the method comprising the steps of:

evaluating an extrusion load when coke cakes pass over a narrow furnace width portion in which a distance between furnace walls is narrowed by a projection portion that exists on the furnace walls of a carbonization chamber of the coke oven, using parameters of an index Qn that is defined by a following equation (1) in consideration of a distance L between the furnace walls, a thickness h of the projection portion, and a total gap w in a furnace width direction; and

considering the total gap w as a gap that is obtained by adding a gap between the furnace walls and the coke cakes on the left and right in a coke cake extrusion direction and a gap amount in a center portion of the coke cakes.

Qn = (h-w)/L ...(1)

2. The method of estimating a load according to claim 1, further comprising the steps of:

repeatedly measuring of the extrusion load under conditions in which the distance L between side walls, the thickness h of the projection portion, and the total gap w in the width direction, while replacing a plurality of projection portions, using an extrusion load measuring test device which can mount the projection portions each having the thickness h which is different from that of another projection portions on the side walls, and obtaining in advance the correlation X between the Qn calculated using the equation (1) as described in claim 1 and the actually measured extrusion load;

calculating an index Qn related to the carbonization chamber of the coke oven from a thickness hi of the projection portion on the furnace walls of the carbonization chamber of the coke oven, a total gap amount W1 in the furnace width direction, which is obtained from the kind of coal charge, and carbonization conditions, and a distance L1 between the furnace walls, using the equation (1) as described in claim 1; and obtaining the extrusion load of the carbonization chamber of the coke oven based on the correlation X and the Qn1.

3. The method of estimating a load according to claim 2, wherein the thickness hi of the projection portion is calculated by integrating profile information of the furnace walls.

4. The method of estimating a load according to claim 2 or 3, wherein the correlation X between the Qn and the measured extrusion load is obtained by applying a predetermined force in an opposite direction to the extrusion direction of the coke cakes when the coke cakes arranged in the extrusion load measuring test device are extruded.

5. The method of estimating a load according to claim 2 or 3, wherein the correlation X between the Qn and the actually extrusion load is obtained by applying the predetermined force from an upper portion of the coke cakes when the coke cakes arranged in the extrusion load measuring test device are extruded.