DD160420A1 - METHOD FOR PRODUCING SOFT BROWN CARBON BRICKS WITH HIGH PYROLYSIS STABILITY - Google Patents

Abstract

The invention relates to a process for the production of soft lignite briquettes with high pyrolysis resistance. According to the invention, the coal is dried to preferably 30-35% water content and homogenized by grinding to a high primary grain fineness. At this water content, the dusty coal can be formed without difficulty and without restriction of the Druckplastizitaet the coal into a ribbon or moldings. These moldings are dried to less than 12% water content, preferably 6-8%, and comminuted to a secondary briquettable fraction which is easy to briquet on conventional types of press. The drying process is carried out in such a way that the secondary conversion reaches the compression zone when heated up. The briquettes are particularly suitable for the production of lignite coke, whereby almost the abrasion resistance of coal coke is achieved.

Description

Title of the invention

Process for the production of soft lignite briquettes with high pyrolysis resistance

Field of application of the invention

With the method according to the invention, pyrolysis-resistant special briquettes made from lignite for the production of coke. The lignite is dried in two stages and homogenized to a high degree. The inventive design of the individual process steps, the formation of Feinststauben is controlled with high efficiency. The coke produced from the briquettes has strength properties close to those of coal coke ·

Characteristic of the known technical solutions

It is known that the pyrolysis resistance of briquettes can be increased with increasing fineness and thus homogenization of Brikettiergutes.

In DD-PS 134958 the increase in the pyrolysis resistance of the briquettes is achieved by JTaßaufschlußmahlung the raw lignite «disadvantageous in this method is the complex technology for dehumidifying the v / ärigen Kohlebreies.

According to DD-PS 143790, it is possible to sufficiently high Pyrolysestandfestigkeiten the briquettes in comminution of dry lignite with a water content of 6 - 12 %

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to produce a dust particle size of at least 0.2 - O mm with a maximum of 5 % oversize and subsequent pressing · As the pressing of dry lignite with form punch presses and roll presses only up to a grain size of 1 - 0 mm and with ring roller presses up to a grain size of 0.5 0 mm, it has been proposed in DD-PS 143790 to granulate the dry lignite with 6-12% water content and a dust fineness of 0.2 - Om to a secondary grain without changing the compressive plasticity and the coarse-grained Brikettiergut thus formed to the usual Pressing press types into briquettes «.

The disadvantage of this method is that lignite dust can be granulated with a water content of 6 - 12 % difficult without reducing the plasticity and the grinding of the dry coal and their granulation at a water content of 6 - 12 % feasible only with increased safety precautions · Also, the hot coal coming from the drying plant cools down in the process stages until compression, so that the desired elevated temperature of the secondary grain for the compression process is not given β

Object of the invention

The object of the invention is the production of pyrolysis-resistant lignite-based briquettes by homogenization x 3 lignite coal with easily manageable process stages and low energy and equipment costs ·

Explanation of the essence of the invention τ

The invention has for its object to overcome the existing difficulties in the production of soft lignite dust briquettes and. to design the process stages of homogenisation, drying and pressing in such a way that they can be operated with high efficiency and effectiveness

According to the invention the object is achieved in that the lignite coal to less than 40 % water content, preferably

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30-35 %, pre-dried and ground at this water content to a high primary grain fineness. Subsequently, this fine dust with the above water content and with the application of a low specific pressure, preferably by roller presses, into films or to formations

which are then processed without disintegration into an excess of very fine grain fraction with comminution devices into a slightly briquettable secondary granule. The shaped articles or the secondary granules are subsequently dried to water contents of less than 12%, preferably 6-8 56, where possible.

l is heated to temperatures greater than 90 ° C. The hot secondary grain is pressed into briquettes with high yield stability by means of form punch, high-pressure roll or ring roll presses.

The method according to the invention is characterized

that the preparation of the raw lignite can be simplified, since a strict limitation of the upper grain boundary, as in a drying of the coal in one step to a water content less than 12 % is required, is not necessary · Furthermore, the drying can be up to said water content less than 40 % operate at high specific evaporation rates · during the drying of the coal to a water content of about · 35 - * 30% it does not experience such high curing as during the drying process to less than

12% · This allows the subsequent homogenization by

The pulverized coal obtained can be easily formed with the relatively high water content of the ultrafine dust largely preventing the pressure

plasticity of the coal, which is important for the compression of the secondary grains, is reduced. In addition, the dust with the increased moisture content is characterized by a lower flowability. · In fine pulverization and formation, the water content differences between fine grain and coarse grain initially present in the dry coal largely balance each other out. This makes it possible to perform the post-drying water contents of less than 12 % at relatively high specific evaporation performance

The formation and comminution to secondary grain can be

Realizing the reduced risk of ignition and explosion of coal and coal dust dried to about 35-30 % , so that the process stages main drying, grinding, forming and processing can be operated to Skundärkorn with limited safety-related effort

Since in the Hachtrocknung only about 30 % of the total amount of water must be evaporated from the coal, it is possible with easily ignitable soft lignite with reasonable effort, the secondary drying of the secondary grain in a protective gas atmosphere or with hot inert gas to very low water contents of ζ · · · To dry 4 - 6 % , wherein the pressing is hot, ie »without cooling the dried secondary grain in a steam atmosphere. Such low water contents of the upgrading briquettes greatly reduce the otherwise considerable expense in the complete expulsion of the briquettes' carbon water in the pyrolysis process. The hot pressing of the secondary granules increases the pyrolysis resistance of the briquettes produced.

A further embodiment of the method according to the invention is possible in that the primary or secondary grain means for increasing the Pyrolysestandfestigkeit or aids that are of importance for the technological use of the coke produced from the briquettes, can be mixed. If such an auxiliary agent contains liquid, it lowers the secondary particle disintegration during drying. · In this case, the admixture must be carried out before the final drying. · If the fine dust properties are improved, it must be added to the primary particle. · If it is necessary to grind the auxiliary agent, then it is to see before the grinding plant. Dust accumulating during the main drying process can be fed to the fine dusts when the milling process is bypassed. Depending on the type of coal and. the selected / water content, the formation of fine dust to avoid any pressure plasticity reductions of the coal occur in a steam atmosphere. For the design of the comminution processes, it is important to know that the degree of comminution in the processing of the raw lignite and the secondary grain for the degree of homogeneity.

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the coal is meaningless.

A variant of the solution according to the invention is the partial or complete coupling of the main drying with grinding to the known mill drying. The mill drying can be operated in such a way that the dusts are screened with the required fineness and the coarse grain fractions are required in a separate grinding plant Fineness be reground. In this variant, a high proportion of very fine dust accumulates, which ensures a very high pyrolysis resistance of the briquettes.

Another variant of the invention is that the formed from the O Peinststaub films are first dried and then comminuted to the desired secondary grain or both processes carried out in an aggregate.

embodiments

1 · example

The raw lignite coal is treated to a grain size of 8-0 mm and dried by means of a tube dryer to an average water content of -30 % . This dry coal passes without cooling to the grinding plant and is comminuted to a grain size of 0.1-0 mm with a maximum of 15 % oversize. By means of two rollers, the fine dust is formed into a 15 mm thick film, which is shredded immediately after emergence from the rolls to a grain size Ö - 8 mm. The secondary granules are gently dried under inert gas to 5 % residual water content and with the outlet temperature of the after-drying aggregate of

»5 100 C pressed in a steam atmosphere. The pressing, carried out with a Formkanalstempelpresse at a pressure of about 120 MPa. From the pyrolysis-resistant briquettes, a coke having a strength equal to that of coal-coke can be produced.

^r 0 2nd example

The raw lignite is crushed to 6 - 0 mm and reaches the grinding drying plant · Here the coal is dried to a water content of 25 % and comminuted to a grain size of 1 mm

Separation of this grain by sighting or gradual separation from the flue gas in the grain sizes 0.1 - 0 mm and 1 0.1 mm. The latter arrives at ITachmahlung. The fine dusts of the mill drying and Hachtrocknung be mixed with each other and with a means to increase the pyrolysis resistance. The finest grain is formed by means of rolling to a film of 8 mm thickness. After being rolled, the film breaks up into individual pieces which are dried to 10 % water content with hot gases in a delivery unit. In the delivery unit, further shredding of the pieces of film takes place to a grain size of 0-8 mm. This secondary grain gets hot, ie without cooling for briquetting by means of high-pressure roll presses *

Claims (9)

> -... ZZ & 975 6 Claim for invention 1) A method for Herateilung of Weichbraunkohlenbriketta) 0 with high pyrolysis resistance, characterized in that the lignite is predried to less than 40 %, preferably 35 - 30% j and milled at this water content for homogenization of the carbon to a high primary grain fineness, then the 2) Method according to item 1, characterized in that the post-drying is performed so that the secondary grain with a high temperature, preferably greater than 90 C, for pressing to further increase the pyrolysis resistance of the briquettes for pressing · > 3) Method according to items 1 and 2, characterized in that the flat drying takes place with hot inert gas or in a protective gas atmosphere down to a low residual water content, preferably below 6 % _t 4) Method according to item 1 to 3, characterized in that the pressing of the secondary grain to increase the Pyrolysestandfeatigkeit the briquettes takes place in a steam atmosphere. 5) The method according to item 1, characterized in that the pre-dried coal adjuvant to increase the pyrolysis or other aids that are of importance for the technological use of the coke produced from the briquette, mixed, wherein the admixing takes place before the fine grinding, if the aids do not have the required degree of dust, ! 0 the admixture takes place before the formation, if the forming properties of the fine dust are improved, the lightening takes place before! Lachtrocknung, if the zz Aid liquid contains and the admixture to the secondary grain takes place, if by their stability is increased. ) 5 fine dusts are formed into foils or into formations which are processed to a secondary grain which can be briquetted on conventional types of press and dried to a low water content, the secondary coring being produced first and the final drying being carried out. > 0 to, or in reverse order, if necessary, in one operation · 6) Method according to item 1, characterized in that the predrying and grinding takes place partially or completely in one operation by the so-called mill-drying. 7) Method according to items 1 and 6, characterized in that during the pre-drying or the combined predrying grinding fine dust particles are added to the primary grain after the actual fine grinding · 8) Method according to item 1, 6 and 7, characterized in that the formation and secondary grain formation or the secondary grain formation and subsequent drying in one operation or · aggregate takes place. 9) Method according to item 1, characterized in that the formation takes place to avoid changes in the plasticity of the carbon in a steam atmosphere.