DE2358122A1 - Coal briquetting process - comprises preheating softening and two compaction stages - Google Patents

Abstract

Coal with poor bonding properties and gas coal is made into briquettes by a process consisting of preheating to the softening temp. and whilst being held isothermally at this temperature subjecting it to a first compaction stage into plastic coal strip to a thickness at least equal to that of the final briquette followed by a second briquette compaction stage. The briquette may be subjected to a further heat treatment to remove volatiles. The process yields a hard coke suitable for use as blast furnace fuel for pig iron production.

Description

METHOD OF MANUFACTURING PLASTIC CHEF BRIQUETTES

The present invention relates to the field of coke chemical technology and more specifically on process for Manufacture of plastic "coal briquettes *

The coal briquettes are used to produce slag coke used.

A number of methods are known for producing coal briquettes by the hot briquetting method, wherein a coal mixture without a compound component is used. It is a Mach part of these processes is that they for manufacturing coal briquettes for the production of metallurgical coke from coal with reduced back assets (sB _e gas coals of the type 711 and 721 according to the international classification) (or from a mixture of gas coals with weakly caking coals coals of Type 411 according to the international classification) cannot be used »

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JThe mentioned procedures must be used as a component of the coal mixture well baked bottleneck coals can be used (see the "Lurgi-Bergbaufortuna-Method", FRG).

Bs are also methods of producing coal briquettes from coals with reduced baking capacity or from a mixture known from gas coals with weakly baking coals without the use of binders, which consist in the fact that the heated Coal is kept under nearly isothermal conditions until thermal coal destruction is required Degree occurs, after which the coal is pressed in a separately installed apparatus.

The disadvantage of this process is that it is impossible to remove the coal, which is kept under almost isothermal conditions until the required degree of destruction is reached to bring, since the coal can pass into the aggregate state and the destruction during the formation of the plastic mass must be terminated at the stage in which the briquettes are being pressed.

For the reason described above, the pressing time of the briquettes becomes extended, i.e. the productivity of the technological process flow is low.

In addition, there is currently a method for producing plastic briquettes from gas coals and low-baking coals known by pressing in one stage.

It is a disadvantage of this method that the briquettes under pressure over a sufficiently long time (8 to 15 seconds) must be maintained in order to create conditions in which thermochemical destruction processes develop in the coal, since the destruction takes a certain amount of time. the The consequence of this is also a low productivity of the

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technological process flow.

It is the aim of the present invention to do the mentioned Cons too. remove.

The present invention is based on the object such a method for producing "plastic charcoal briquettes" (which are used in the production of metallurgical form coke) in which the duration of the stage during which the finished coal briquettes are pressed does not differ from that for the present coal type required duration of the formation of the plastic coal mass under pressure depends, making it possible borrowed becomes, the productivity of the technological process flow in comparison to the known method of the corresponding type.

This task is in a method for creating plastic Coal briquettes from gas coals and weakly baked coals dissolved, which consists in the fact that the coals mentioned on Softening temperature are heated, after which the heated coal is kept and pressed under almost isothermal conditions is, according to the invention, the heated coal in two stages is pressed and in the first pressing stage a plastic carbon ribbon is formed, the thickness of which is at least equal to that specified Briquette thickness is, while in the second pressing stage, plastic coal briquettes are pressed from the aforementioned carbon strip will.

According to the present invention, the carbon band is expediently formed at a pressure of 2 to / 15 kp / cm in the course of 5 to 10 seconds, while the individual briquettes are formed at a pressure analogous to that mentioned above in the course of 0.05 to ^: 0 , Be pressed for 4 seconds.

The method according to the invention makes it possible to produce coal briquettes

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for the production of metallurgical form coke from gas coals and from a mixture of gas coals with low-baking coals (coals of the types 711, 721 or 411 according to the international Classification), which have a low baking capacity and only briefly in plastic when heated Remain state. In addition, it became possible to produce the coal briquettes in a high-performance technological continuous process to create.

This is achieved (without the use of binders) by using the limited natural resources of the coal mentioned in baking ability through rules of destruction, synthesis and Polycondensation process of the organic carbon substance can be used. These processes have the emergence of a plastic Phase and the formation of a gas-impermeable plastic carbon mass result and ensure the generation of briquettes and the molding of metallurgical coke bit a sufficiently homogeneous structure.

According to the present invention, the starting coal (gas coals or a mixture of gas coals with weakly baking coals) previously crushed so that about 90% of the total Coal consist of particles less than 3mm in size, after which the latter is heated to the softening temperature of this coal will.

The duration of this heating, as we have established, is said to be shorter than the time which is required for its thermochemical destruction to develop in the coal.

The heated coal is kept under almost isothermal conditions for 15 seconds to 1.5 minutes without being pressurized, until there are thermochemical destruction processes in the carbon structure to develop.

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In order to create such conditions, the ambient temperature at which the heated coal is kept should be at most 100 to 150 ^° C. below the softening temperature of the coal present.

Then the coal is pressed in two stages.

In the first stage, the coal is held under almost isothermal conditions under a pressure of 5 to 15 kp / cm for 2 to 15 seconds, a plastic carbon ribbon being obtained, the thickness of which comes close to the specified briquette thickness. At this stage developing in the coal Destructions-, synthesis and polycondensation of organic carbon substance _f diezu end are performed. In addition, the formation of the plastic carbon mass is ended.

Then, in the second pressing stage, the finished, plastic The structure of the carbon band under an analogous pressure of 2 to 15 kp / cm individual briquettes in the course of 0.05 to Pressed for 0.4 sec.

We have found that when the coals used are under the conditions prior to pressurization or under pressure in the course of a for the present coal or the present Coal mixture remains insufficient time, the formation processes of the plastic mass are not terminated. If, on the other hand, the coals remain too long under the conditions mentioned, processes take place in the carbon structure which cause these carbon to become brittle.

In both cases, the influence on the molded coke made from such briquettes is negative (it becomes brittle) and the amount of waste during molding increases ».

If the pressure is insufficient for the coal or mixture of coal present, the strength of the

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produced plastic coal briquettes less. The latter can be used during conveyance and further heat treatment are partially destroyed, whereby the amount of waste increases. If the pressures are too high, the porosity of the briquettes and the Coke made from them is insufficiently low, which has a negative effect on the behavior of the molded coke in the blast furnace.

The attached drawing shows the basic implementation scheme of the method according to the invention.

The heated to softening temperature coal A is given as bulk material in a device 1, in which it in the course is maintained under nearly isothermal conditions for a predetermined period of time without the application of pressure. The hold time depends on the specifics of the coal being processed. The device 1 can be one of the for Devices suitable for this purpose, for example as a screw or apron conveyor, are designed.

The coal is conveyed from the device 1 into a pressing device 2, where it is pressed for the first time (the first stage) and where a plastic carbon ribbon is produced from the coal, which consists of bulk material. The pressing time (i.e. the Haltzöit under pressure) and the size of the pressing pressure are dependent on the particularities of the to be processed Coal elected.

The pressing device 2 can be designed according to the type of one of the known devices, for example as a compression molding machine .

From the pressing device 2, the plastic carbon ribbon arrives in a pressing device 3, where it is pressed again (the second stage) and formed into coal briquettes B. The pressing device 3 can according to the type of one of the known pre

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directions, for example briquette press, are carried out, with dimensions and volume of the briquettes B technological Should meet the requirements for molded coke.

All of the devices listed above can be used as a single Machine running.

From the pressing device 3, the coal briquettes get into a baking furnace to produce shaped metallurgical coke.

According to the method according to the invention were in an industrial Test facility 15,000 tons of plastic coal briquettes made from gas coals and a mixture of gas coals low-baking coals of various types that are not a bottleneck material and from which no metallurgical coke can be produced by other known processes. Of the Coke made from these briquettes was placed in an industrial furnace tried.

Example 1 -

When processing gas of coal (carbon type 711 according to the international classification) previously heated to the temperature of 452 ⁰ C carbon is maintained at a 300 to 35O ⁰ C draw ambient temperature over a period of 50 sec to 1 min without applying pressure. The charcoal is then pressed at a pressure of 2 to 3 kp / cra ^ in the course of 10 to 15 seconds, a plastic band of carbon up to 60 mm thick being obtained. The latter is formed into pillow-shaped briquettes with a ^{volume of approximately 70 cm x 5} and a thickness of 35 to 40 mm at a pressure of up to 8 to 10 kg / cm ^2.

The briquettes are heat treated in the hot state (at 800 to 85O ⁰ C heated), remove volatile substances. Here, molded coke is obtained with a volatile substance content of up to 1.5% and the following characteristics: M ^ ₀ approx. 90% and

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3YLq approx. 6.5 to 7.0%. Such a coke ensures when it is melted of pig iron results in a reduction in coke consumption and an increase in the blast furnace throughput compared to its use of coke, made from coals that bake well using the traditional method of coking in layers in chamber ovens was obtained.

Example 2.

When processing of a mixture of 60% Gas carbon (carbon type 721 according to the international classification) and 40% weakly caking coal (carbon type 411), the carbon mixture to a temperature of 460 + 4 ° C heated at an ambient temperature of 350 to 400 ⁰ C in Maintained for 30 + 2 seconds and subjected to a pressure of 5 to 6 kp / cm for 6 to 8 seconds, a 40 to 50 mm thick, plastic carbon ribbon is obtained. The latter is transformed into cushion-shaped plastic briquettes with a pressure of up to 10 kp / cm in the course of 0.2 to 0.3 seconds, the dimensions of which are 62x62x35 mm. The briquettes are treated while hot to remove volatile substances. Here, molded coke is obtained with a volatile substance content of up to 1.5% and the following characteristics: M ^ q approx. 90% and M, q approx. 7%. When smelting pig iron, such a coke ensures a reduction in coke consumption and an increase in the blast furnace throughput compared to the use of coke obtained from well-baked coals by the conventional method of layer-by-layer coking in chamber furnaces.

It is understood that those skilled in the art can make various changes in the method of producing plastic coal briquettes can make, since the procedure is exclusively in the form of a no-limit-setting example, which does not have the Goes beyond the scope of the invention.

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Claims (2)

Claims - 1. Process for the production of plastic coal briquettes from gas coals and. weakly baking coals, which consists in that the mentioned coals are heated to softening temperature, after which the heated coal is kept and pressed under almost isothermal conditions, since through geke η η I η eti that the heated coal is pressed in two stages; wherein a plastic band is formed in the first carbon Preßstadium whose thickness is at least equal to the predetermined Brikettdicke, while in the second pressing stage _s, plastic coal briquettes are pressed from the said carbon ribbon. 2. Method for producing plastic charcoal briquettes according to Claim 1, d a d u r cn g e k e η η ζ ei cn η et, ■ '- that the plastic carbon band at a pressure of 2 to 15 kp / cm is formed over the course of 5 to 15 seconds while the individual Briquettes at a pressure analogous to the above, pressed in the course of 0.05 to 0.4 seconds. . 509821/0 B 9 7 L e r s e i t e