EP0042114A2 - Process for manufacturing a coal feed mixture for coking plants - Google Patents

Abstract

According to the invention, the range of coals suitable as replacement components for coconut coal in a mixture with self-propelled coals is substantially enlarged. In particular, this is done by grinding the non-self-propelling coals and self-propelling coals separately, before heating the non-self-propelling coals to a minimum of 150 ° C and a maximum of 250 ° C and compacting the non-self-operating coals to form lengths. The mold lengths are only added to the self-propelled coal on the way to the coke oven, the mixing proportion of the mold length being no more than 60%.

Description

The invention relates to a process for the production of feed coal mixtures using non-self-propelled coals.

The development of coking technology is essentially in two directions. On the one hand, the coke quality should be improved. On the other hand, the range of carbons is to be enlarged. The latter direction of development is attributable to the effort to include the fine grain content of coal in the coking process. Before use in the coking plant, the coking coal is typically ground to a grain size between 0.5-10 mm with a proportion of 30% to 35% smaller than 0.5 mm and 80% to 85% smaller than 3 mm or from correspondingly fine-grained products Coal processing mixed. In the past few decades, the proportion of fine grains in raw production has increased significantly. In addition, there were other influences that led to an increase in the fine grain content of the coking coal. If the fine grain content of the coking coal exceeds a certain level, then its bulk density decreases and the coking chamber is impaired, because the capacity of the coke oven chamber decreases proportionally to the bulk density. Furthermore, the cooking time is longer because the heat transfer in the bulk is poorer with a reduced bulk density.

It is known to counteract this by part of the. Coal is coarsened by agglomeration. Classifier dust, flotation concentrate and possibly raw sludge should preferably be used. In a long-term concept, this technology included thermal drying of reprocessing products and subsequent agglomeration.

The proposal to influence the grain structure of the input coal by mixing differently ground coals can serve both development directions. It shows that there is an optimal grain structure.

In addition to the grain structure, the maceral group analysis or the volatile constituents of the input coal are decisive for the coke formation capacity. I.e. The optimal coke formation capacity can also be represented, for example, as a function of the volatile constituents in the input coal. This leads to the possibilities described in the journal "Glückauf - Forschungshefte", 4, 1966, page 1/192 for the production of optimal coking coal mixtures by using different coal components, which differ both in the grain size and in the volatile components. Although the coking of non-self-propelled coals is also known, the coking process is generally adversely affected by the addition of non-self-propelling coal. For this reason, only small amounts of non-self-sufficient coal have so far been able to be added to the coke feed mixtures.

The invention has for its object to significantly increase the range of suitable as replacement components for coking coal in a mixture with self-propelled coals.

According to the invention this is achieved in that the self-propelled coal and the non-self-propelled coal are ground separately and the non-self-propelled coal minimally to 150 ° and max. is preheated to 2500 C and compacted into blanks and the blanks of the self-propelled coal are only added on the way to the coke oven, the blending proportion of the blanks not exceeding 60%. The proportion of the mixture is preferably not less than 30%. In the process according to the invention, the non-self-propelled coal is processed separately from the self-propelled coal and brought into such a form that an optimal grain structure and the necessary homogeneous grain distribution can be easily produced, and both components complement each other in such a way that the optimal coke-formation capacity is reliably achieved . Contrary to the reduction in coke quality to be expected from earlier knowledge, the preparation according to the invention of the non-self-sufficient coal and the increase in its coking capacity according to the invention even lead to a significant improvement.

As a rule, the non-self-sufficient coal is compacted using a coal binder. Carbopech, residues from coal oil processing and oil refinery residues come into consideration as coal binders. When using these carbon binders, the conventional measuring methods for determining the coke formation capacity fail. As a result, it was not possible to measure the suitability of coal binders via measured coke formation capacity. to conclude its improvement.

After adding the coal binder, the coal is fed to a mixer and / or kneader in a further embodiment of the invention. Mixing and kneading should ensure homogeneous distribution of the coal binder in the coal places, ie prevent accumulations and agglomerations. After mixing and kneading, the insert coal can be stored easily.

According to the invention, the compacting takes place with the production of regular moldings with a jacket or rod shape. The thickness is between 15 and 30 mm. The length to thickness ratio is max. 3: 1 and not less than 1: 1.

The drawing shows the exemplary embodiment of a device for producing coal insert mixtures according to the invention.

Non-baking coal and coking coal are fed separately in grinders 1 and 2 for grinding. Instead of the two separate mills 1 and 2, a single mill can also be used if the non-baking coal and the coking coal are fed in one after the other and, as a result, known processing steps can be carried out after the grinding.

The ground coking coal is fed from the mill 2 to a bunker 3. The coal can be continuously withdrawn and placed in a Vorerhitzungsanlage 4 from the hopper 3, which it is heated depending on the nature 1500-250 C ^0. The coal is preheated with a view to adding warm moldings later. As a result, a high level of mixing is achieved, which leads to better filling of the gap volume occurring in cooperation with the moldings.

Optionally, the Kohlcvorheating system 4, as shown at, 5, can also be bypassed in the event of a fault. In addition, heating can be dispensed with if aqueous emulsion is used as the carbon binder.

The non-baking coal ground in the mill 1 is conveyed either directly or indirectly via a mixer 6 into a kneader 7. The kneader 7 is used to mix the ground non-baking coal with auxiliary materials. When the feed coal is fed indirectly through the mixer 6, small portions of the self-propelled coking coal have been branched off into the transport stream of the non-self-propelling coal. The proportion of branched off self-sustaining coking coal is max. 30% and serves to replace the missing baking capacity of the non-self-sufficient component.

The auxiliaries can either be introduced into the kneader 7 in solid form or be added in liquid form. The solid auxiliary substances are optionally ground in a further mill 8 before they meet the coal.

After leaving the kneader 7, which is a homogenization, i.e. ensures uniform distribution of the auxiliary materials in the feed coal, the coal reaches a bunker 9. The mixture can be withdrawn continuously from the bunker 9 into a preheating system 10. In the preheating system 10, water is expelled, which is a hindrance to a subsequent compaction process. According to the invention, contrary to conventional compacting technology, the water is not regarded as a binding agent but as a separating liquid which interferes with the compression process. If the feed material has a sufficient degree of drying with regard to later compacting, the preheating system 10, as shown at 11, can also be bypassed.

The non-self-propelled charcoal then enters a compactor 15 either via a mixer 12 or a double cross-type mixer 13 with a kneader 14 connected downstream. The compactor 15 is a double-roller press or an extruder. The double-roll press produces almond-shaped or rod-shaped moldings, the thickness of which is between 15 and 30 mm, depending on the material to be used. The length to width ratio is max. 3: 1 and is not less than 1: 1.

Before entering the double cross-stroke mixer 13, the auxiliary substances provided in liquid form can optionally be sprayed on. In order to produce the liquid state of matter, the heating-up station 16 is preceded by a heating system 17 when the auxiliary materials, in particular residues, are solid in the initial state. The injection is preferably carried out in a freely falling coal stream in a closed container. Optionally, the compactor 15 can also be bypassed, as shown at 18, 19 and 20. At 18, the insert coal can be fed to a separate spray station 21, double cross mixer 22 and kneader 23 and then placed in coke ovens 24.

All of the feed coal streams coming from the separate processing of the non-self-sustaining coal are combined and mixed with the refilled, self-sustaining coal before entering the coke ovens 24. The coal coming through the spray station 21 is mixed with the self-moving coal before entering the mixer 23 and kneader 22. The system according to the invention is particularly suitable for the preparation of various insert cabbage components. This involves separate grinding and the combination of preheating and compact turned off. The combination of preheating and compacting leads to the highest efficiency in the conditioning of the feed mixtures.

The highly pronounced bloating ability of the moldings compared to the surrounding self-sufficient fine coal is considered essential for increasing the coke quality. The system according to the invention enables the coal preparation to be optimized specifically for each type of coal. This makes the coking process trouble-free and significantly improves the coke's characteristic values. The system allows different procedural steps to follow one another and to be able to bypass them. As a result, the strength of the moldings required for the desired coke quality can be achieved with the least effort. In addition to improving the coking properties, the plant according to the invention enables the use of a wide range of coal types. The compacting of the non-self-sustaining coals produces moldings with special pyrolytic activities, which give rise to swelling at the contact points formed during the coking process. A comparable effect is created by preheating the carbons to up to 250 ° C. Both process steps complement each other in a special way.

In the exemplary embodiment, the proportion of moldings in the mixture with self-propelled coal does not exceed 60%. This also applies to the proportion of all moldings in the mixture. Compacting the self-launching coal should be avoided if possible. The proportion of moldings in the mixture according to the invention leads to a significant increase in the bulk density which favors the coking process and a substantial increase in the Productivity in horizontal chamber coking.

The strength of the coke is largely determined by the strength of the moldings. The strength values are explained below using tests with almond-shaped moldings (length 32 mm, width 14 mm) and rod shape (length 52 mm. Width 15 mm).

In the explanations, reference is made to M ₁₀ and M 40 values. The M 10 and M 40 values indicate the abrasion resistance of coal. A so-called micum drum serves as the test device.Bci during the movement of the test drum creates abrasion which remains after sieving the test material over a perforated plate as sieve residue. M 10 is the sieve residue fraction below 10 mm, M 40 is the sieve residue fraction above 40 mm.

The improvements in the abrasion M 10 of the coke are analogous to the compressive strengths of the moldings, the higher the strength of the moldings, the greater the quality improvement of the coke. With the cold-pressed rods and almonds there is a significant increase in compressive strength and a corresponding and noticeable improvement in the M 10 value. In the case of hot-pressed rods and almonds, the compressive strength of the moldings is considerably greater and there is a serious improvement in the M ₁₀ value of the coke. The improvement in the M ₁₀ values following the strength of the moldings "is attributed to the fact that, with the strength of the moldings, the internal gas pressure in the pyrolysis of the briquetted inhalation mixtures is responsible for the expansion and has a decisive influence on the product.

Details can be found in the table below. In this table, oils 1 - 4 are residual oils from Rohol refining.

Claims (5)

1. Production of feed coal mixtures for hokerei using non-self-propelled coal, characterized in that self-propelled coals and non-self-propelled coals are ground separately and the non-self-propelled coal to a maximum of 250 ° C and min. is preheated to 150 ° C. and compacted into moldings and the moldings are mixed with the self-propelled coal on the way to the coke oven (24), the proportion of mixtures of the moldings not exceeding 60%. 2. The method according to claim 1, characterized by the use of Carbopech, oil refinery residues or residues from the Kohlcoöaufberototung as coal binder for compacting, the coal after adding the coal binder to a mixer (14, 23) and / or kneader (13, 22nd ) is supplied. 3. The method according to claim 1 or 2, characterized by the production of regular moldings when compacting with Mandcl or rod shape. 4. The method according to claim 3, characterized in that the length to the thickness of the moldings does not exceed the ratio 3: 1 and not less than 1: 1. 5. The method according to claim 4, characterized in that a known roller press is used for compacting.

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