US2166321A - Method of producing semicoke or coke from carbonizable solid fuel material - Google Patents

Description

A. POTT July 18, 1939.

METHOD'OF PRODUCING SEMICOKE OR COKEFROM CARBONIZA BLE SOLID FUEL MATERIAL Filed Oct. 16, 1955 INVENTO/fi ALFRED POTT Patented July 18, 1939 r UNITED STATE-S1 METHOD OF PRODUCING SEMICOKE OR COKE FROM CARBONIZABLE SOLID FUEL- MATERIAL Alfred Pott, Essen-Ruhr, Germany Application October 16, 1935, Serial No. 45,306 In Germany October 17, 1934 5 Claims.

The invention relates to carbonaceous material having the structure of semi-coke or full coke.

The invention further relates to a method of producing semi-coke and full coke. 1

It is an object of the-invention to render th carbonaceous material free of non-combustible admixtures forming ashes, when the material is burned.

Another object of the invention is to make products of semi-coke and coke being freepor practically free, of non-combustible admixtures.

In the known production of semi-coke, the carbonaceous solid fuel material consisting in coal. particularly gas coal, is subjected to dry distillation in a temperature range between about 450 to 550 C.

In the known methods of producing dense coke which will simplybe called coke in the subsequent specification, the coke is obtained by dry distillation of suitable coal at temperatures between about 850 to about 1000 C., sometimes up to about 1100 C.

The semi-coke or coke so obtained is free from volatile constituents to a certain desired degree, and forms, according to the character of the original material and the treatment, a more or less strong and coherent mass.

If such semi-coke or coke is burned, there remains a substantial amount of ash formed by non-combustible parts of the original coal matefrial. If such semi-coke or coke is burned in regular ovens, the ash may be removed without dis turbing the operation. If using, however, such semi-coke or coke for particular purposes or in particular ovens, these non-combustible admixtures cause considerable difliculties and sometimes prevent the use of' such coke.

According to this invention a semi-coke or coke is produced being practically free from such noncombustible admixtures whereby the disadvantages mentioned above are removed.

According to this invention semi-coke or coke is produced not directly from the original carbonaceous material. 1% first intermediate products are formed which are already free, or practically free, of undesired non-combustible mixtures, and these intermediate products are then subjected to dry distillation in order to obtain the desired semi-coke or coke. 1

According to this invention, extracts are formed (Cl. 2M-33) U. S. Patent 1,881,927 of-which I am a co-inventor.

In general such extracts may be produced by subjecting the solid carbonaceous material to extraction by means of low or high boiling organic solvents or mixtures of them, such as hydrated organic oils, phenols, phenols containing oils, acidic oils etc. The carbonaceous material may .be used as obtained in the mines in more or less large lumps, or the material may be powdered .to any desired degree, down to diameters of a micron of the particles. The carbonaceous material is then subjected, in the presence of a suflicient amount of solvents, to a heat treatment under normal or elevated pressure, and extracts dissolved in the solvent media are finally obtained in yields and of proportions depending on the nature of the original carbonaceous material, the kind of solvent mediaand the conditions of temperature and pressure applied.

The extracts separated from the solvents in any suitable Way and preferably filtered so as to remove also any traces of non-combustible and not dissolved admixtures, form solid bodies when cooled which in turn form the intermediate material now subjected to dry distillation according to this invention, in order to transform them into semi-coke or coke. The material subjected to such dry distillation being free, or practically free,

from non-combustible ashes forming admixtures,

the semi-coke or coke obtained therefrom must also be free from these non-combustible admixtures.

While it is principally immaterial for the invention in what shape and form the extracts are subjected to dry distillation, it is sometimes advantageous to 'admix to them a substantial amount of powdered coke, or semi coke, obtained by a foregoing process in order to prevent the formation of foamy coke. Furthermore, by such admixtures the formation of a dense and strong coke is secured. The amount of these additions depends on the character of the extracts subjected to dry distillation. While in some cases no such additions are necessary, in other ones a few percent of the additions referred to suffice, and it may sometimes be advisable to add such powdered coke in amounts up to 20% and more.

Any method and apparatus ordinarily used in the production of coke and semi-coke may bev used for the purpose of this invention.

The best results have been obtained by subiecting extracts to dry distillation in a temperature range between 450 C. up to about 1100 C.

which are obtained from coal, lignite, peat by treating them with organic oils, or mixtures of such oils, at successively raised temperatures close to, particularly a little below the decomposition temperatures of the original carbonaceous material under treatment and the solid residues resulting during the proceeding extraction, respectively. Such treatment is best performed in closed vessels at pressures rising according to the rising temperatures. A particular advantageous process is described in U. S. Patent 1,881,927 mentioned above. Thereby highest temperatures are finally arrived at corresponding to the decomposition temperature of the last solid residues which are not capable anymore of being dissolved or extracted but decompose only if the temperature were further raised.

If, for instance, a gas-coal having 28% volatile constituents is treated according to the invention of the patent mentioned above, thenthe original material will first develop gases, i. e. start to decompose, if heated up to about 330 C. If such coal is treated in the presence of organic solvents at a temperature of about 320 to about 330 C., a substantial part .of the material is dissolved. The non-dissolved solid residue will start to decompose again, i. e. develop gases derivi'ng from volatile constituents still present therein at a higher temperature, viz. at about 350 C. Therefore, this residue is treated in the presence of the same solvents at a temperature between 340 to 350 (3., whereby an additional part ofthe residue is dissolved or, as it is called, extracted.

In this way one proceeds in determining the 35. decomposition temperatures of all the residues after the following extracting steps, until one arrives at a final temperature which does not yield any extracts any more. A gas coal as mentioned before, yields residues having a decomposition temperature of 330, 350, 380, 400 andfinally4l0 to 415 C., and consequently the extraction will be performed at rising temperatures close to 330,

.350", 380 and lastly about 400 and 410 C.

Thereby optimal yields ofextracts are obtained, such as 85% in the example shown above.

The temperature does not have to be raised gradually in the way described before, but may be continuously raised taking care, however, that the rising temperatures do not materially exceed the decomposition temperatures of the residues formed in each case.

It is obvious that the temperatures and the duration of extraction during which the temperatures are raised depend materially on the material under treatment and the solvents applied.

Preferably organic solvents, such as hydrogenated oils, acidic oils and mixtures of them are used.. Tetraline, phenols, cresols, low tempera! ture tar-phenols are preferred.

The solvent media containing acidic oils and hydrogenatedoils are particularly advantageous, on account of the depolymerizing action of acidic oils upon the carbonaceous substance while hydrogenated oils are capable of dissolving the carbonaceous substance so depolymerized. A small part of the carbonaceous substance is hydrated also by hydrogen given up by the hydrated oils during extraction, Mixtures of solvent media may contain.besides of acidic oils and hydrated oils, also hydrocarbons. Mixtures of about 60% tetraline and about 40% cresols, or of about 40% tetraline, 40% naphthaline and cresols have been proven as useful. The amount of solvent media may be equal to that of carbonaceous material to be treated thereby, or the solvent may be present in excess as for instance 1.5: 1.

The extracts so obtained are practically free of ash viz. its amount is less than 0.1% and can be reduced to less than 0.05% by suitable filtration of the extracts while still dissolved, such filtration preferably to be done at raised temperature and pressure as described in my copending application Ser. No. 14,794 filed April 5, 1935..

When subjecting such extracts after separation from solvents to dry distillation in a temperature range between about 450 C. to 1000 C. and 1100 C., semi-coke and coke is obtained useful for various purposes.

Particularly bodies adapted for electrical purposes, such as electrodes may be made from such coke which are practically free of ashes. Such bodies and electrodes when used for metallurgical purposes, permit to obtain metals of a purity unknown up to date.

So for instance aluminium may be obtained practically free of impurities which has, due to such extreme purity, properties which have been unknown up to date. Furthermore, metallurgical processes are rendered more economical and efiicient by using such bodies and electrodes because time taking and difficult purifying processes may be dispensed with.

Furthermore, graphite and graphite containing bodies may be obtained from a coke or semicoke, produced according to this invention, in an unknown high quality. It is clear for everybody versed in the art that the process of its manufacture is considerably facilitated and made cheaper.

While a semi-coke or coke obtained from an extract may still contain non-combustible admixtures in amounts up to about 0.1%, it is possible, according to this invention, to remove it also. To this effect the extracts separated from the last residues of the solid carbonaceous material may be filtered while still being dissolved, at elevated temperature and pressure, whereby the content of non-combustible and insoluble admixtures is further reduced down to amounts which are hardly to be ascertained by ordinary methods. If additional removal of traces of such admixtures is desired, then, according to this invention, the extracts separated from the solvents may be treated with acids such as hydroclhoric acid, sulphuric acid and other acids at normal or elevated temperatures. Inorganic acids are preferable because organic acidsalthough effective are more expensive and might dilute the extracts or the solvents which are preferred to be still present during this treatment with acids. The strong inorganic acids referred to may advantageourly be diluted for instance with water. If treating the extracts with such acids at elevated temperatures up to about 50 or 60 C., and above, the traces of nomcombustible and insoluble admixtures are reduced down to 0.05% and 0%, i. e. to amounts which can only be ascertained by most elaborate methods in the laboratories. The extracts so treated and freed from any undesired admixtures may then be subjected to smouldering or coking.

An apparatus suitable for the purposes of the invention is shown in the drawing in a diagrammatical way and for exemplification purposes only. In the drawing the production of the extracts themselves is not shown. I refer in this respect in particular to S. Patent 1,881,927. The solid extracts having a suitable shape, viz. larger or smaller lumps, or everrbeing ground to a desired degree, are brought intoa hopper I and released from it upon a belt 2 which is led around rolls 3, l and moved with suitable and adjustable speed in the direction of the arrow 5. Thereby the depth of the layer deposited onto the belt 2 can be regulated. Another hopper 6 is arranged in front of hopper l and filled with semi-coke or coke of extracts previously produced, This semicoke or coke may have any desired shape from larger lumps down to finely ground particles. The semi-coke oncoke is deposited upon the layer 1 of extracts on the belt 2, and both deposits are then delivered into .a mixer 8 of any suitable. type.

- After an intimate mixture has been performed,

the extracts are delivered into any suitable type of coke oven as shown at 9. This oven is provided with heater I and with a hydraulic main i I through which the gases and vapors developed during smouldering, or coking are released into a suitable condenser. In this oven the extracts impurities, furthermore free of occluded gases. When used for instance in metallurgical processes, they give dense and pure products free from included bubbles.

Finished graphite bodies may be subjected to smouldering at temperatures between about 390 C. to 550- C. in order to remove-any traces of these two ranges, then an intermediate type of coke is obtained which is sometimes required.

It is understood that any other type of oven for dry distillation can be used such as retorts, rotating drums provided with a heater from inside or outside, etc.

The semi-coke or coke so obtained may either be used directly for the desired purpose. or transformed into particular products, such as graphite for lubricating purposes, or for electrical machines, electrodes. etc,

If the manufacturing of graphite is desired, preferably coke is subjected to heating up to a temperature of about 4000 C. which is preferably done in high frequency oven.

If brushes or electrodes are to be manufactured, preferably coke is taken, advantageously comminuted and then mixed with an organic hinder or semi-coke, or extracts before being subjected to a coking process, and the more or less plastic mixture is then shaped in molds or by extruding through a die, then dried-if necessaryand then heated to a temperature at which graphiti zing occurs.

According to this invention, the extracts may also be shaped and subjected to graphitizing without first being separately smouldered or coked. Such smouldering and coking may occur while the extracts are heated up to the graphitizing temperature whereby volatile constituents are removed to a desired'degree. For this purpose the extract still dissolved in the solvent,

or separated from it, may be molded or cast into molds, and then heated preferably in the mold then given the final desired shape. If using the .extracts still dissolved or filtered they may be cast or molded immediately. a

It is to beunderstood that the graphitizing to be done preferably in a non-oxidizing atmose volatile material if still present in the material.

What I claim is:

1. The method of producing coke from solid carbonizable fuel material, substantially ,conslstingin firstproducing carbonizable extracts from said material by heat treatment in the presence of solvents, then treating said extracts while dissolved with diluted inorganic acids, and

finally coking said extracts in the absence of said solvents and acids.

.2. The method of producing semi-coke from solid carbonizable fuel material, substantially consisting in first producing carbonizable extracts from said material by heat treatment in the presence of solvents, then treating said extracts while dissolved with diluted inorganic acids, and finally subjecting said extracts to dry distillation in the absence of said solvents and acids at temperatures ranging between about 450 to 550 C.

3. A method of producing semi-coke or coke from carbonizable solid fuel material, comprising presence of solvents at elevated pressure whereby perfectly free of ashes and other incombustible carbonizable extracts dissolved in said solvents are obtained, separating said extracts from solid residues of said material, and the novel steps of treating said extracts with acids, separating said extracts from said solvents and acids, and subjecting said finally separated extracts to coking by heat treatment between about 450 C, and about 1100 C.

4. A method of producing semi-coke or coke from carbonizable solid fuelmaterial comprising phere such as a carbon-dioxideatmosphere. If

manufacturing electrodes in'this way, they are the steps of treating said material in the heat and under elevated pressures in the presence of a solvent whereby carbonizable extracts are obtained dissolved in said solvent, separating said extracts from solid residues of said material, separating said extracts from said solvents, and the novel steps of mixing said separated extracts with coke previously obtained from extracts in a; process as described in claim 3, and subjecting this mixture to coking by heat treatment between about 450 C. and 1100 C.

-5. A method of manufacturing articles containing graphitized semi-coke or coke, comprising the steps of treatingcarbonizable solid fuel material in the presence of solvent media, said solvent media containing at least a major portion of organic solvents, in the heat and under elevated pressure, said temperatures not exceeding the decomposition temperature of the solid residues of said material finally obtained, whereby carbonizable extracts dissolved in said solvent media are obtained, separating said extracts from said last residues, and the novel steps of treating said extracts with diluted inorganic acids, separating said extracts from said solvent media and was, coking said extracts by heat treating them between about 450 C. and about 1100 0., shaping material comprising said semi-coke or coke, and graphitizing said shaped material by heat treatment up ;to about 4000 C. I

HIRED POTT.

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