CS204121B1 - Process for preparing valuable coke from non-baking or only weakly baking black coal - Google Patents

Abstract

Prodn. of high=grade lump coke from non-coking or low-coking coal involves crushing to fineness of 1/0 mm., homogeneous mixing with binder pref. in amt. of 7.5-12% briquetting under high press. of 600, pref. 1000 kp/cm2 min. at a temp. dependent on the binder, and coking with rapid heating, pref. at 30 degrees K/min., without previous thermal oxidn. The binder may be pitch, but also suitable are high boiling and asphalt-rich tar and oil-processing products which cannot be used for normal briquetting and coking. Organic waste prods., esp. scrap rubber, may be mixed with the binder to improve its properties. Stability of the briquettes is improved and volatilisation of the binder during heating-up reduced, so that odixative pre-heating of the briquettes is eliminated. Costs are reduced and economic use made of water materials, e.g. scrap tyres. which can be emulsified in the binder, e.g. coal tar, in ratio 1:3-10.

Description

The invention relates to a process for the production of valuable lump coke from non-caking or low-caking hard coal.

It is known that solid lump coke provides only those kinds of hard coal that have sufficient coking capacity. Such types of hard coal are coke with a grain size of 0 to 3 mm: up to 0 to 8 mm, mostly in horizontal and occasionally also in standing chamber furnaces. In these coking processes, hard coal is usually poured into the coking chamber without prior compaction. To a lesser extent, the hard coal is pre-compacted by light upsetting before being introduced into the coking chambers. In addition, it is known that the coking properties of hard coal improve with increasing grain fineness. However, the fineness of the grain has its limits, because with increasing fineness of hard coal its bulk or shaking volume decreases at the same time, which is negatively reflected in the performance of the coking plants and the strength of the coke. The bulk density of coal is occasionally attempted to be increased by the addition of oil or other bituminous products. However, the success of such measures is small.

It is further known that the coking properties of poorly sintered hard coal types can be improved by mixing tar pitches or high-boiling oil distillation residues. In addition, it is known that it can also be produced from relatively poorly sintered types of hard coal lump coke when pre-briated black coal with a grain size of 0 to 4 mm, mixed with tar pitches or high-boiling oil distillation residues as binders. pressures of 20 to 40 MPa on cylindrical presses, and these pressings are before coking. heat stabilized by oxidative heat treatment at temperatures around 250 degrees Celsius. Without the pre-thermostabilization of the binder moldings, these valuable lump coke do not provide, since the briquette binder will leak out or distill off, before forming, a stable coke bond. In addition, the moldings lose their original shape during the heating period. In any case, lump coke is obtained if the hard coal already has a very good coking capacity. In this case, however, previous briquetting is uneconomical.

Low-boiling products, such as coal-tar, are not suitable as a binder in this process, since they already degrade off during the oxidative thermal pretreatment of the compacts or leak out of the briquettes.

In addition, processes are known in which fine coke or non-caking kinds of hard coal with low volatile fractions are briquetted together with well-caking kinds of coal by hot briquetting at pressures above 400 ° C and then coke. Briquetting may also be performed with suitable binder ¹ at temperatures between 60 and 120 ° C. In both cases, however, proportions of expensive sintered hard coal species are required, mostly above 30%.

It is further known that the coking power of black! coal improves with increasing heating rate. However, the increase in the heating rate is limited in the horizontal or standing chamber furnaces hitherto used, since the heat transfer is relatively small due to the low thermal conductivity of the heated walls of the silicate material chamber and in particular of the loose or steamed black coal. times of over 16 hours. The heating of the hard coal can be accelerated according to known methods, firstly by pouring the hard coal into the coking chambers already preheated - but this requires an additional device - on the other hand it is possible to increase the heating rate by using the direct coking method. Utilization of the principle of coking by direct heating (low-temperature carbonization) requires the use of coarse-grained coal or briquettes and assumes in the additional operation the oxidation of lump coal or thermostabilization of the briquettes.

The purpose of the invention is to reduce these drawbacks in coking of non-caking or low-caking hard coal, while increasing the coke quality in terms of lumpiness and strength, and to increase the economic effect.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process according to which it is economically advantageous to produce lump-free or non-caking types of hard coal. high strength coke.

The above task is. According to the invention, the untreated hard coal is ground to a grain size of less than 1 mm, homogeneously mixed with binders such as pitches, tar-rich tars, petroleum residues, coal tar, rubber. from old tires, in a quantity of 7.5 to 12 wt.%, briquetting at temperatures of 70-100 ° C and pressures from 60 to 100 MPa to obtain a compact coked quickly, by heating, especially at 30 K min ^-1 in the range of medium temperature 600 ° C to high temperatures of 1100 ° C, the technology being used comprehensively.

Suitable presses are preferably cylindrical presses with forming wells. In accordance with the invention, with compression! this fine-grained hard coal by high pressing pressure ^! closes the binder in the briquette · so tightly that the otherwise usual leakage of the binder during the heating period before the actual coke formation phase is suppressed very strongly. These fine briquettes, produced under high compression pressure, also have good dimensional stability during heating.

The rapid heating of the strongly pressed fine-grained briquettes according to the invention makes it possible to stabilize the homogeneous distribution of the binder in the briquette during the heating period as well as to improve the shape stability of the compact.

Fine grain of non-caking or low-caking hard coal below 1 mm, high pressure briquette pressing together with rapid heating of the briquettes according to the invention makes it possible to obtain a very strong, dimensionally stable coke in a short coking time without additional oxidative thermal treatment. This is mainly due to the combination of different principles of action, so that the uniform distribution of the binder up to! the coking phase itself, even without thermo-oxidation of the compacts, the solid bridges resulting from the coking binder form a continuously consolidated lump coke.

At the same time, the newly developed coking process provides the added advantage that it can be made from non-sintering or only slightly sintering hard coal without additional oxidative thermal treatment of the compact, even when binder is used with binder with a coal tar consistency. In addition, pitches, all high-boiling and asphalt-rich petroleum products and blown bitumen are also suitable as binders for this process according to the invention. In addition, a mixture obtained by emulsifying old rubber from used automobile tires in coal-black tar at a tar / rubber weight ratio of 3: 1 to 10 has proved to be a binder.

The process according to the invention is further illustrated by two exemplary embodiments.

Example

Piece coke is produced from the following. Ingredients:

92.5% by weight of hard coal with a grain size of 0 to 1 mm with 36% volatiles

7.5 ° / o propene resins.

After homogeneously mixing the components, briquetting is performed on a roller press with molding wells at a pressing temperature of about 70 ° C and a pressure of about 100 MPa. The briquettes are then subjected to rapid coking with heating · from 600 ° C in 100 minutes to about 1000 ° C. The cooled lump coke has the following characteristics:

Shape stability: 100%

Drum Strength: · R 30 84.8% (after · 300 turns in 0 500 mm drum)

Volatile shares: 0.20%

Sulfur content: 1.14%

Example 2

Lump coke is produced from the following ingredients: .....

% by weight, 0 - 1 mm black coal with 36% volatiles,% by weight, a mixture of coal tar and old rubber (6: 1 ratio).

Portions of old rubber, for example from old automobile tires, are emulsified in coal tar. The binder thus prepared is mixed with finely ground coal at 70 ° C. Briquetting and coking are carried out as in Example 1.

The cooled lump coke has the following characteristics:

Shape stability: 100%

Drum Strength: R 30 93.0% (after 300 turns of 0 500 mm drum)

Volatile proportions: 0,32%

Sulfur content: 1.02%

Claims (1)

Process for producing valuable lump coke from non-sintering or only slightly sintering hard coal by grinding, mixing with binder and briquetting, characterized in that untreated hard coal is ground to a grain size of less than 1 mm, homogeneously mixed with binder such as pitch, tar-rich tars. to asphalt, oil residues, coal tar, rubber from old tires, in the amount of 7.5 to 12 why, by weight, briquetting at temperatures of 70 to 100 ° C and pressures of 60 to 100 MPa, the moldings obtained are coke by rapid heating especially at a rate of 30 Kc. min t, in the range of medium temperatures of 600 ° C to high temperatures of 1100 degrees Celsius.