EP0002198A1 - Method and apparatus for the production of coke - Google Patents

Abstract

The process for producing coke, in particular furnace coke, uses considerable amounts of lean or relatively lean caking coal which is submitted to compaction so as to obtain pressed substances; these pressed substances are used on their own or mixed with additional material as charge in a coke furnace for the coking. The coal (A) is submitted during compaction to forces acting upon different directions (D, T) in order to create shearing and/or rotating stress. This causes the mutual fixing of the coal particles thus giving highly resistant pressed material with a high degree of conservation. During compaction, heat can be brought to the material. A device for application of this process comprises a matrix and an element which makes the material pass through the channels of the matrix. These channels have different diameters and can also have different lengths.

Description

The invention relates to a method and an apparatus for the production of coke, in particular blast furnace coke, using larger proportions of low-baking or weakly baking hard coal compared to normal baking, in which coal feed material is subjected to a compacting treatment to form pressed bodies and from Products resulting from this treatment can be used as contents for the coke oven for coking in it.

While the strength of blast furnace coke increases as the blast furnaces grow and their specific throughput increases, the amount of first-class coking coal available in the most important coal-producing countries decreases. To an increasing extent, therefore, hard-baking hard coal, often also those with a high content of volatile components, have to be involved in the production of this Filling material for the coke oven feed mixture forming coke oven are involved, so that further technical measures have to be used in order to be able to produce high-quality and solid blast furnace coke even under these conditions.

A process that has long been used in large-scale operations for the production of high-quality coke from coking coal mixtures, which consist to a large extent or predominantly of weakly baking coal, is the so-called ramming operation, in which, by tamping the coking coal outside of the coke oven, a "ramming cake" mechanically "is produced, which is pushed into the furnace chamber. By "pounding" the coke oven filling can be increased in weight, because the pound cake reaches a volume weight of about 1000 kg / m ³ , while the bulk weight of moist coal normally filled into the chamber is only 650 to 750 kg / m ³ depending on the water content and grain size is. This considerable increase in bulk density during ramming has resulted in a decisive improvement in coke quality.

Since the ramming operation entails high installation and operating costs, it was proposed to instead compact the coking coal before filling it into the coke oven by briquetting in double-roll presses and to fill the briquettes directly into the coke oven. In doing so, however Due to the low strength of the briquettes produced by roller presses at normal temperature, the latter decays so much that the chamber filling contains only 20 to 30% of briquettes but 70 to 80% of fine coal. Therefore, the compression of the chamber filling only increases by 10 to 15% compared to normal pouring operations.

In order to increase the strength of the briquettes and thus their degree of preservation after filling the coke oven, it can be considered to mix the coking coal or an appropriate part of it with binders such as tar, tar pitch, petroleum residues and the like. to briquette in the usual way at 80 to 90 ^° C. However, it is disadvantageous that not only does this result in significantly higher costs for the binder and for the briquetting at correspondingly higher operating temperatures, but also that difficulties and hazards at the workplace as well as environmental pollution are caused by the inevitable emission of tar and oil vapors.

Processes for preheating coking coal have also been developed, in which coking coal at a temperature of about 200 ° C. can be filled into the coke ovens. This results in an increase in the bulk density of the coal compared to the coking of wet coking coal in bulk operation by 10 to 15% and a corresponding improvement in the coke strength. However, the installation and operating costs of a coking plant with heating the coking coal are considerably higher than that of the nor paint bulk operation. They should be even higher in the order of the "ramming operation".

The object of the invention is to overcome existing difficulties and disadvantages in the production of coke, in particular blast furnace coke, and to open up a way of baking weaker with reasonable effort when used. hard coal to receive a feed for coke ovens, be. the compact formed by a compacting process are such that a favorable degree of filling or a favorable filling weight when charging the coke oven ₃ and thus a high coke resistance can be achieved. With this water-related further problems, with which the invention is concerned, arise from the respective reauthorization of the solution shown.

The invention takes into account the knowledge that an optimal increase in the chamber filling or bulk density by 20 to 40% could be achieved if 60 to 70% of the bakets would enter the chamber undamaged and the intermediate space would be filled accordingly. In a method of the type mentioned at the outset, the invention provides that during the compacting, the feed material generates both a pressure which leads a guided feed movement of the material in a main direction and a force which additionally increases the combination of the material particles in the main direction of compression deviating direction in the sense of a shear or shear stress and / or a rotating stress.

In such a treatment of the feed material, not only are forces acting in one direction or, as in the case of a double roller press, in opposite directions, but forces are simultaneously exerted on the material which push the parts of the material in a pushing and / or rotating manner . In this way, a special mechanism of mutual attachment and connection of the different and differently sized coal grains is achieved, for example in the sense of "interlocking" them. The result is compacts with a high strength, so that a very good degree of conservation of the compacts is achieved in the filling operation, even if they fall several times from a greater or lesser height when charging the coke ovens by means of a filling car, possibly after an intermediate bunkering.

In the described type of compacting, the loading of the feed material can also cause the latter to heat up, as well as elements that come into contact with it. This promotes the formation of a hard outer skin of the pressed body.

Depending on the circumstances, the compacts produced according to the method described can fill the product alone make up the coke oven or add non-compacted material, e.g. fine coal, to it. It depends on the properties of the components whether the compact is used alone as a filling or whether it is mixed with fine coal. The addition of strong-baking coals to the pressed bodies made from weakly baking coals according to the described process can have a more favorable effect on the coca strength than if the mixture of both coals is completely compacted.

The method according to the invention is carried out particularly favorably in such a way that the material is shaped like a strand during the feed movement in the main pressing direction and is subsequently exposed to an action which leads to division into pieces. This action can be a cutting, dividing or breaking to which the strand formed is subjected, or it can in particular be such that the sid-forming strand is exposed to the action of gravity, so that individual pieces break off under their influence . For this purpose, the main pressing direction is selected essentially vertically downward and the strand is left with a sufficient free path on which it is not supported or otherwise held.

In a further embodiment of the method, the invention provides that heat is supplied to the material during the compacting process. This can, for example, by radiation or by using elements in contact with the feed material as a heat source. The addition of heat also contributes to increasing the strength and results in particular in a hard outer shell of the pressed body.

The process according to the invention can be carried out with coal in the state in which it is obtained, i.e. with about 6 to 12% moisture. However, it may also be advantageous to use dried feed material containing or preheated to over 100.degree. C. coal, although the compacting can then only be carried out with the addition of substances which act as lubricants. It has thus been found that it is expedient to add predried brown coal to the feed material, the proportion of the latter in the mixture of the feed material being 4 to 8 percent by weight. For example, with a dried and preheated to over 100 ° C coking coal mixture with a larger proportion of hard, highly volatile coal by a small addition of pre-dried lignite, the required strength of the compacts can also be achieved.

The invention further provides that an addition of comminuted high-melting hydrocarbons is added to the feed material, in particular if the coal is dried and preheated to over 100 ° C. eg of ground hard pitch, hard bitumen or coal extract. Such an addition, which in particular can amount to approximately 2 to 6% of the feed material, has a particularly favorable effect on the coke resistance, since these solid hydrocarbons act as "back bitumen".

The addition of comminuted solid hydrocarbons is also considered for the purpose of improving coke when compacting low-baking coal without prior drying and heating, both when the compacts are used alone and when they are used in a mixture with better-baking fine coal as a filling material for coke ovens.

In a particularly advantageous manner, a device designed in the manner of a roller press is used for the compacting process, which has a die with channels and at least one press wheel or the like which can be rotated relative to the die in the area of the channels of the latter. having. It can be, in particular, a device with a horizontally arranged, fixed, vertical channels having die, on which a pair of rollers designed as a pan run rotates. However, it is also possible to use a device in which a die with channels is rotated under a pair of rollers rotating on the spot.

In any case, the use of such a device for compacting the feed material in the forces acting in different directions within the same, which result in a feedstock for coke ovens with the desired properties in the manner explained above.

In order to supply heat to the material in the desired case, when using a device of the type specified, at least one of the two parts which can be rotated relative to one another (die, press wheel) can be heated while working, in particular with the aid of electrical heating elements or the like.

One embodiment of the method which is favorable for achieving the highest possible bulk density in the koke oven chamber is that compacts of different piece weights and / or different sizes are produced simultaneously.

An advantageous device for forming pressed bodies, which has a die provided with channels and at least one element pressing the feed material through the channels, in particular a device designed as a roller press, is characterized according to the invention in that the die has channels of different diameters. The channels in particular also have different lengths.

Such a device is particularly suitable for carrying out the method explained. It can be used to produce different compacts in one operation in order to achieve a high bulk density in the coke oven chamber. In addition, the device is also important for the production of compacts of different weights or sizes from other feed material and for other uses.

• Fig. 1 schematisch das Prinzip des erfindungsgemäßen Verfahrens bei einer Ausführungsmöglichkeit,
• Fig. 2 eine weitere Ausführungsmöglichkeit des Verfahrens,
• Fig. 3 eine Draufsicht zu Fig. 2
• Fig. 4 eine Ausführung einer bei dem Verfahren zu verwendenden Vorrichtung, größtenteils im Schnitt,
• Fig. 5 eine vorteilhafte Ausbildung einer Matrize in Draufsicht und
• Fig, 6 einen Schnitt nach der Linie VI - VI in Fig. 5 in etwas anderem Maßstab.

The invention is explained below with reference to the drawing with exemplary embodiments shown therein. Show it:

• 1 schematically shows the principle of the method according to the invention in one possible embodiment,
• 2 another possible embodiment of the method,
• 3 is a top view of FIG. 2
• 4 shows an embodiment of a device to be used in the method, mostly in section,
• Fig. 5 shows an advantageous embodiment of a die in plan view and
• Fig. 6 shows a section along the line VI - VI in Fig. 5 on a slightly different scale.

As illustrated in FIG. 1, the feed material A is given a feed movement in the main press direction during compression by compressive forces D acting in a main press direction P, and forces are also applied to the feed material, the direction of which deviates from the main press direction P or transversely to this, as indicated by the arrow S, so that the feed material is simultaneously subjected to a shear or shear stress. Such feed and shear forces can be generated in different ways.

Fig. 1 shows a on the top of a molding M, such as a plate, slidable body G with a wedge-shaped inclined front, which acts on the feed material A in the manner explained and acts upon movement in the direction of arrow Z in the manner explained pushes through an opening K in the mold M. This opening advantageously has a round, in particular circular, cross section. As a result, in addition to linear shear or shear effects, rotating loads can also be achieved in the feed material. The body G can also be chamfered at both ends, as shown, and can then be moved back and forth in the direction of the double arrow Z '.

2 and 3 illustrate an embodiment of the method in which the stresses to be imparted to the feed material A are applied by a wheel-like body R. become, which is rotatable on a horizontal axis C, which is pivotable about a vertical axis E (Fig. 3) or rotatable by means of such an axis in the direction of arrow U, so that the wheel body R in turn in a molding tool M. Opening K can be moved away. The vertical axis E is at a distance from the opening K. The width of the wheel body R is greater than the diameter of the opening K which is circular in cross section. With respect to this opening and the feed material, there is no simple rolling movement, but one occurs combined movement with a pushing part, as can be seen from FIG. 3, in which two further positions of the wheel body R are shown in broken lines. Thus, in addition to compacting compressive forces D (FIG. 2), which at the same time give the feed material a feed movement in a main pressing direction P, additional forces acting in directions deviating from the main pressing direction, such as those indicated schematically by the arrow, also result in such an embodiment are who subject the feed material to shear or shear stress and here also to rotating stress.

The compacted strand emerging from the opening K breaks off by itself after a certain length or can be brought to a break by a short blow, so that individual pressed bodies are produced.

4 shows a device suitable for the method according to the invention in its entirety. This contains a housing with e.g. a closed jacket 2 or more legs 1 and an upper part 3. Both parts are detachably connected to each other by a flange 4. In a receptacle 5 of the lower part 1 is e.g. made of steel die 6 used, which contains a plurality of channels 7 in an annular region B, the shape of which is substantially cylindrical. In the embodiment shown, two press wheels 8 run on the top of the die 6, the width of each of which is slightly larger than the width of the ring region B containing the channels 7, so that the latter completely covers the press wheels 8 while rotating and with the weight of the press wheels and the build-up pressure is applied.

The press wheels 8 are rotatably mounted on a horizontal axis which is held by the lower part 9 of a vertical shaft 10. The shaft 10 runs in axial and radial bearings 11, 12 and carries a gear 13 which is connected to it in a rotationally fixed manner and which, via further gear elements, indicated only by dash-dotted lines 14, e.g. Gears can be driven to rotate by an electric motor 16, a pinion seated on the output shaft of the latter being designated by the number 15.

In the rest of the closed working space of the press wheels 8 through an inlet 17 feed material, about weaker baking hard coal in granular form and with normal moisture. The size of the inlet or the like by means of a slide, not shown. changed or blocked. The feed material is pressed by the press wheels 8 as they circulate into the channels 7 of the die 6, as has been explained above in principle in connection with FIGS. 2 and 3, and leaves them in the form of fixed press strands. These break off after reaching a certain length under the effect of gravity and / or under the influence of other influences, so that individual pieces result which fall in the direction of arrows F into an adjoining space 20, for example a shaft which is above of the filling car of a coke battery or can get to a bunker through the pressing body directly or via a transport device.

3 in the illustrated embodiment of the device designed in the manner of a roller press, the die 6 is also provided with a heating device which is largely indicated schematically by the letter H, energy supply lines being numbered. 18 are designated. This can be a resistance heater, an inductive heating device or some other suitable embodiment, it still being possible to heat the entire die or only the vicinity of the channels 7.

The additional heat supply to the feed material made possible during the compacting process in this way depending on the circumstances, the temperature can be selected according to the type of feed material, in particular in such a way that the softening point of the material or of a component thereof is reached or exceeded. This leads to melting and welding phenomena during the press molding, especially in the area of the edge zone.

In order to achieve the highest possible bulk density in the coke oven chambers, it can be advantageous if a die for the production of the pressed bodies has channels with different diameters, so that differently sized or heavy pressed bodies are obtained simultaneously in one and the same production process.

As an example of this, FIGS. 5 and 6 each show a part of a die 21, namely a die for a roller press of the type shown in FIG. 4 or similar, which has two groups of channels 22 and 23 with different diameters D1 and D2. The term channel here means a cylindrical part of the entire passage in the die 21 which represents the actual compacting space. In the embodiment shown, conical regions 24, 25 and cylindrical end regions 26, 27 adjoin it. The channels 23 with the larger diameter D2 are longer than the channels 22 with the smaller diameter D1. Instead of two groups of channels With different diameters, the die can also have more groups with other different dimensions.

All of the features mentioned in the above description or shown in the drawing, if the known prior art permits, should be regarded as falling within the scope of the invention on their own or in combinations.

Claims (15)

1. A process for the production of coke, in particular blast furnace coke, using larger proportions of weakly baking or weakly baking hard coal compared to normal baking, in which coal feed material is subjected to a compacting treatment to form compacts and products resulting from this treatment as filling material for the coke oven is used for coking in this, characterized in that the feed material during the compacting both a pressure which produces a guided feed movement of the material in a main pressing direction and a force effect which additionally strengthens the combination of the material particles in a direction deviating from the main pressing direction in the sense of a thrust - or subjected to shear stress and / or rotating stress. 2. The method according to claim 1, characterized in that only the product resulting from the compacting treatment is used as a filling material for the coke oven. 3. The method according to claim 1, characterized in that the product resulting from the compacting treatment of the weakly baking coal is used as a mixture with uncompacted better baking coal as the filling material for the coke oven. 4. The method according to any one of claims 1 to 3, characterized in that the material is shaped like a strand during the feed movement in the main pressing direction and is then subjected to an action leading to division into pieces. 5. The method according to any one of claims 1 to 4, characterized in that heat is supplied to the material during the compacting process. Process according to one of claims 1 to 5, characterized by the use of pre-dried and pre-heated to 100 ° C. Charging material containing or formed by this. 7. The method according to any one of claims 1 to 6, characterized in that brown coal is added to the feed material. 8. The method according to claim 7, characterized in that the proportion of lignite in the mixture of the feed material is 4 to 8%, based on dry matter. 9. The method according to any one of claims 1 to 8, characterized in that an addition of comminuted, high-melting hydrocarbons is added to the feed material, especially the weakly baking coal. 10. The method according to claim 9, characterized in that the addition is about 2. to 6% (weight percent) of the feed material. 11. The method according to any one of claims 1 to 10, characterized in that a device designed in the manner of a roller press is used for the compacting process, or the like, a die with channels and at least one relative to the die in the region of the channels of the latter rotatable press wheel or the like . having. 12. The method according to claim 11, characterized in that at least one of the two relatively rotatable parts (die, press wheel) of the device is heated during the work of the same. 13. The method according to any one of claims 1 to 12, characterized in that compacts of different piece weights and / or different sizes are produced simultaneously. 14. Apparatus for forming pressed bodies, in particular for carrying out the method according to claim 13, which contains a die provided with channels and at least one element pressing the feed material through the channels of the die, characterized in that the die (21) has channels (22, 23) of different diameters (D1, D2). 15. The apparatus according to claim 14, characterized in that the channels (22, 23) have different lengths.

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