EP0130170A2 - Method for regularizing the distribution of the coal charge in a coke oven chamber - Google Patents

Abstract

1. Process for controlling the distribution of the coal charge in a cell of a coke oven, in which the levelling of the coal charge loaded into the said cell is performed, characterized in that before the said charge is coked, at least one lengthwise profile of the upper surface of the charge in the said cell is recorded, in that the recorded profile is compared with a profile considered to be ideal for the said cell, in that the location and the value of the differences existing between the recorded profile and the ideal profile are detected and in that the charging and/or the charge levelling operation in the said cell is acted upon so as to annul the said differences.

Description

The present invention relates to a method of regulating the loading of a: coke oven ellule.

In a battery of coke ovens, the various carbonization cells are charged according to a predetermined sequence, by means of a machine, called an oven, mobile above the ovens. This oven has a limited number of hoppers, generally four, which are distributed along the length of the cell and to which corresponds an equal number of loading orifices provided at the top of each cell. The charging machine is itself supplied with coal from a coal tower which pours into each hopper the quantity of coal required.

During the loading of a cell by the oven, there is formed, under each hopper, a mound of coal whose importance is fixed by the angle of slope of this coal.

Obviously, these mounds cannot be left behind, which would quickly cause the loading orifices to become blocked and thus prevent the correct filling of the cell.

The destruction of these mounds of coal in formation is generally carried out by the repalage operation. This consists of spreading the charcoal put into the cell as best as possible, by means of a device, most often in the form of a horizontal grid provided with a vertical front plate, which is introduced at the top of the cell. .

The re-leveling operation normally involves several outward and third return strokes of the leveler.

• - d'assurer l'enfournement d'une quantité maximale de charbon compatible avec le volume de la cellule,
• - d'obtenir un chauffage uniforme de la charge,
• - de produire un coke de qualité uniforme,
• - de réduire au minimum l'espace libre au-dessus de la charge et d'éviter ainsi toute surchauffe et tout craquage du gaz présent dans cet espace, et par conséquent de prévenir tout dépôt de graphite susceptible de freiner le transfert de chaleur à travers les parois des cellules,
• - de diminuer les différences de température dans les parois des cellules et par conséquent de réduire les contraintes thermiques dans ces parois.

The advantages of a correctly executed re-leveling are well known to those skilled in the art. We can briefly recall that it allows:

• - ensure the charging of a maximum quantity of coal compatible with the volume of the cell,
• - to obtain uniform heating of the load,
• - to produce coke of uniform quality,
• - reduce to a minimum the free space above the load and thus avoid any overheating and any cracking of the gas present in this space, and consequently to prevent any graphite deposit liable to slow the heat transfer through cell walls,
• - reduce the temperature differences in the cell walls and therefore reduce the thermal stresses in these walls.

In modern coking plants, the repalage is carried out according to a well-defined sequence, which is linked to that of the oven. However, it can be seen that, whatever the technique currently used for carrying out the repositioning, the topographic profile of the upper surface of the load does not have a constant level over the length of the cell. This means that the coal charge is not distributed uniformly in the cell and that the quality of the coke produced will not be absolutely uniform.

To the knowledge of the applicant, however, there is no process applied industrially for the _cab systematically control the distribution of the load and ensure uniformity of this distribution in the cell.

In addition, the resetting as it is currently carried out does not take account of various market incidents which can have significant repercussions on the regularity of the charging of the coal.

• - le bouchage total ou partiel d'une trémie de l'enfourneuse, qui se traduit par un manque de charbon dans la partie correspondante de la cellule et une vallée plus ou moins profonde dans le profil supérieur de la charge;
• - un excès de charbon aux extrémités de la cellule, qui peut donner lieu à un bourrage et une obstruction de la colonne montante ou, au retour de la repaleuse, à une éjection de charbon hors de la cellule par l'orifice d'introduction de la repaleuse;
• - un excès de charbon dans une trémie de l'enfourneuse, pouvant provoquer l'obstruction de l'orifice d'enfournement correspondant et empêcher la fermeture normale de cet orifice;
• - un manque de charbon dans une trémie de l'enfourneuse, qui peut également provoquer un creux dans la surface supérieure de la charge.

Among the most frequent incidents, we can cite as an example:

• - the total or partial blockage of a hopper of the oven, which results in a lack of coal in the corresponding part of the cell and a more or less deep valley in the upper profile of the load;
• - an excess of carbon at the ends of the cell, which can give rise to a jamming and an obstruction of the riser or, on the return of the planer, to an ejection of carbon out of the cell by the orifice of introduction the spreader;
• - an excess of coal in a hopper of the oven, which can cause the obstruction of the corresponding loading opening and prevent the normal closing of this opening;
• - a lack of coal in a hopper of the oven, which can also cause a hollow in the upper surface of the load.

The present invention relates to a method for systematically controlling the distribution of the load in the cell and ensuring the uniformity of this distribution while taking into account the various incidents likely to disturb the regularity of the charging.

It further relates to a method for carrying out the automatic regulation of the loading of coke ovens.

11, the method for regulating the loading of a coke oven cell, which is the subject of the present invention, in which the loading of the charge of coal charged into the said cell is carried out, is essentially characterized in that there is at least one longitudinal profile of the upper surface of the load in said cell, in that the profile measured is compared with a profile considered to be ideal for said cell, in that the location and the value of the differences existing between the profile are detected reading and the ideal profile and in that one acts on the operation of loading and / or shifting the load of said cell so as to cancel said deviations.

According to a first mode of implementation of the method of the invention, the evolution of the shifting force is determined, preferably continuously, as a function of the movement of the leveler during at least one stroke of that -this, and a longitudinal profile of the upper surface of the load is deduced therefrom before said stroke of the spreader.

This first method of implementing the invention is based on the ob-. servation according to which the shifting force varies according to the position of the leveler and according to the stroke of the latter to which we refer.

According to an interesting variant of this first method, the curve of the shifting force is established during several strokes of the spreader,) n compares the curves corresponding to said strokes and the evolution of the longitudinal profile of the surface is deduced therefrom higher than the load of said cell.

Within the framework of this first modality, it is possible to determine the shifting effort by any means known per se. An interesting way is to measure the torque developed by the motor driving the repaler.

Another means which has also been found to be advantageous consists in measuring the pressure exerted by the load on the front plate of the planer.

According to a second method of implementing the method of the invention, there is an upper longitudinal profile of the load, after at least one stroke of the planer, by means of a feeler resting on said load. A first variant of this second method consists, according to the invention, in raising said profile by measuring the angle made, with a predetermined reference direction, of a rigid element of known length connecting a probe to a movable point moving according to a predetermined trajectory, located for example on the grader. During a stroke of the planer, the probe traverses the upper surface of the load, the profile of which can thus be determined by a simple angle measurement.

[lt goes without saying that normally the probe rests on the load. However, if the vertical distance between the said movable point and the surface of the load becomes greater than the length of the said rigid element, the probe will no longer rest on the load and the measurement of the angle would indicate a significant dip in the load at the place considered.

This angle measurement is preferably carried out continuously; it would not, however, depart from the scope of the invention to measure only the angles having a deviation greater than a predetermined value with respect to an angle corresponding to a profile considered to be ideal.

According to a second variant of this second method of implementation, the distance between various points of the measurement is measured, by means of at least one feeler resting on the surface of the load and connected to the marking machine by a variable length element. top surface of the load and a predetermined reference point, for example located on the spreader.

The higher the number of measurement points, the higher the accuracy of the profile.

As a purely illustrative example, it is possible to use in this variant a device of the "fishing rod" type and to measure the length of wire between a feeler, fixed at the free end of the wire, and any reference point.

According to a third method of implementing the method of the invention, at least one tube, preferably vertical, the end of which is situated at a predetermined level, is introduced into the upper part of said cell, a gas under pressure is blown into this tube, the pressure prevailing in this tube is measured in order to determine whether its end is or is not covered by the load. The operation is repeated at several points distributed over the length of the cell and a longitudinal profile of the upper surface of the load is deduced therefrom. In particular, these tubes can be fixed at the end. free from the spreader. The pressure of the gas in a tube varies depending on whether the end of said tube is or is not immersed in the load.

By using several tubes whose free ends are located at different known levels, arranged for example in the form of a "pan flute", it is possible to determine the level reached by the charge at different points of the length of the cell.

It should be remembered here that the spreader is introduced overhanging in the oven cell. Because of its great length, frequently reaching 15 m, the repaleuse can therefore present, in the extreme position, a large deflection which, if not taken care of, could distort the measures provided for by the second and third methods below. above. However, it is possible to know the deformation of the planer under the effect of its own weight and it is therefore easy to correct the measurements made under the two aforementioned methods accordingly.

According to a fourth method of implementing the method of the invention, the distance, preferably vertical, separating the point of the point of the upper surface of the load and a predetermined reference point, at different points of the length, is measured by telemetry. the cell.

In a first variant of this fourth method, it has proved to be interesting to choose a benchmark located on the planer, preferably near the end of the latter. The position of this teper point, at any point along the length of the cell, is in fact known from the moment when the deformation of the repaler is known.

A second particularly advantageous variant of this fourth feature consists in measuring simultaneously, at various points of the length 3rd the cell, preferably vertical distances separating any reference point and the upper surface of the load on the one hand and this same reference point and the vault of the cell on the other hand, to add the two distances thus measured and to deduce therefrom a profile of the upper surface of the load relative to the vault of said cell.

Also in this variant, said reference point is advantageously located on the marking machine, for example in the vicinity of the free end thereof. The measurement is, however, independent of the position of said reference point and it is therefore no longer necessary to know the deformation of the marker to establish a correct profile.
Preferably, these distance measurements are carried out by means of at least one ultrasonic rangefinder placed at the free end of the planer and whose receiving element constitutes the benchmark for the measurement.

According to a fifth method of implementing the method of the invention, the temperature and the position of several points of at least one of the walls of the cell, as well as of several points of the upper surface of the load, are noted, establishes the heat map of a surface comprising the part of said wall located above the load and the upper surface of the load, the area where a large area appears is detected on said heat map. temperature variation, and we deduce the profile of the charge along said wall.

This modality is based on the fact that the part of the cell wall not covered by the charge is at a temperature above 800 ° C, while the upper surface of the charge of fresh coal is at a temperature below 100 ° C. The passage from one to the other surface results in a sudden jump in temperature which is used, according to the invention, to determine the upper longitudinal profile of the load along the wall.

According to a sixth method of implementing the method of the invention, the level of several points on the upper surface of the coke salmon is measured by telemetry during the latter's discharge, when they are passage through a predetermined section of said cell, the position of the shedding shield corresponding to the passage of said points in said section is noted, and a longitudinal profile of the upper surface of the load is deduced therefrom.

This modality is based on the hypothesis, largely confirmed by experience, according to which the upper surface of the charge does not change appreciably during the cooking of the coal. The upper surface of the coke salmon can therefore be considered as a representative image of the upper surface of the charge of fresh coal.

Within the framework of this sixth modality, it has proved to be advantageous to measure the level of the said points of the upper surface of the coke salmon in a section of the oven situated upstream from that where the coke salmon begins to collapse, the upstream being considered in relation to the direction of progression of the coke salmon.

According to the present invention, the measurements required by the various abovementioned methods can be carried out continuously over the whole or only over part of the length of the cell or of the coke salmon.

Finally, it would not be outside the scope of the present invention to combine together, in any way, several of the methods which have just been described.

Furthermore, the present invention encompasses any method making it possible to act on the loading and / or shifting operation of the load of said cell, insofar as, as explained above, it aims to reduce or to cancel the discrepancies noted between the raised profile and the) ideal profile of the upper surface of the load.

In this regard, it has been found advantageous, according to the invention, to modify the quantity of coal supplied by at least one hopper of the charging machine as a function of the said discrepancies observed.

In particular, such a modification can be carried out by modifying the weight of coal discharged into the hopper (s) considered, or by interrupting the flow of coal when the hopper has supplied the predetermined quantity.

To this end, it has proved advantageous to measure, preferably continuously, the weight of the coal contained in the hopper. Such a measurement also makes it possible to detect incidents such as blockages of the hopper, bonding of coal in the hoppers or interruptions of the flow of coal.

Also according to the invention, it is possible to vary the opening sequence of the hoppers of the oven so as to modify the distribution of coal in the cell according to said discrepancies observed. It is thus possible to prevent coal jamming under the riser or the ejection of coal through the introduction hole of the spreader.

It is also possible, still according to the invention, to vary the flow rate of one or more hoppers of the oven so as to provide the profile) of the upper surface of the load with a desired change.

Finally, it is also possible, in the context of the present invention, to adapt the course of the repositioning operation as a function of the said discrepancies observed. Within the meaning of the present invention, this means that it is possible to modify in particular the moment of starting and / or stopping the repaler, the number of strokes thereof or its speed of movement as a function of the indications provided by the comparison of said profiles.

Claims (10)

1. A method of regulating the loading of a coke oven cell, in which the load of charcoal charged in said cell is carried out, characterized in that there is, preferably continuously, at least one longitudinal profile of the upper surface of the load in said cell, in that the profile measured is compared with a profile considered to be ideal for said cell, in that the location and the value of the deviations are detected existing between the raised profile and the ideal profile and in that one acts on the loading and / or shifting operation of the load of said cell so as to cancel said deviations. 2. Method according to claim 1, characterized in that the evolution of the shifting force is determined as a function of the position of the leveler, during at least one stroke thereof, in that a longitudinal profile of the upper surface of the load is deduced therefrom before said stroke of the leveler. 3. Method according to claim 1, characterized in that there is an upper longitudinal profile of the load by means of a feeler resting on said load and connected to a point moving along a predetermined path, preferably to a point of the leveler, by means of a rigid element of known length, in that the angle made by said rigid element with a predetermined reference direction is measured during at least one stroke of the leveler and in that a longitudinal profile of the upper surface of the load is deduced therefrom. 1. Method according to claim 1, characterized in that there is an upper longitudinal profile of the load to the core of a feeler resting on said load and connected to the repaler by an element of variable length, in that the the length of said element is varied until said probe rests at a point on the upper surface of the load, in that the distance separating said point from the upper surface of the load is measured and a predetermined reference point preferably located on the marking machine, in that the operation is repeated at several points on the surface of the load distributed over the length of the cell and in that a longitudinal profile is deduced therefrom of the top surface of the load. 5. Method according to claim 1, characterized in that one introduces, in the upper part of said cell, at least one tube, preferably vertical, the end of which is located at a predetermined level, in that the '' a gas under pressure is blown into said tube, in that the pressure prevailing in said tube is measured, in order to determine whether its end is or is not covered by the charge, in that one repeat the operation at various points distributed over the length of the cell and in that one deduces a longitudinal profile of the upper surface of the load. 6. Method according to claim 1, characterized in that one measures by telemetry the distance, preferably vertical, separating a point from the upper surface of the load and a predetermined reference point, in that one repeats l operation at several measurement points distributed over the length of the cell and in that a longitudinal profile of the upper surface of the load is deduced therefrom. 7. Method according to claim 1, characterized in that the temperature and the position of several points of at least one of the walls of the cell are noted, as well as of several points of the upper surface of the load, in that that we establish the heat map of a surface comprising the part of said wall located above the load and the upper surface of the load, in that we detect on said heat map the area where appears a significant variation in temperature and in that one deduces therefrom the profile of the charge along said wall. 8. Method according to claim 1, characterized in that when the coke salmon is discharged, the level of several points on the upper surface of the said salmon is measured by telemetry when they pass through a predetermined section of the said cell, that we note the position of the shedding shield corresponding to the passage of said points in said section, in that there is deduced a longitudinal profile of the upper surface of the load, said predetermined section being preferably located upstream, with respect to the direction of progression of the coke salmon, from that in which the said coke salmon begins to collapse. 9. Method according to either of claims 1 to 8, characterized in that the opening sequence and / or the flow rate of the hopper of the oven are varied so as to modify the distribution of the coal in the said cell, according to the said discrepancies observed. 10. Method according to either of claims 1 to 9, characterized in that one modifies the moment of starting and / or stopping of the repaler, the number of strokes thereof and / or its speed of movement, depending on the indications provided by the comparison of said profiles.