CA1142109A - Method and apparatus for converting coal to hydrocarbons by hydrogenation - Google Patents

Abstract

INVENTION OF
Klaus Koch TITLE OF THE INVENTION
"Method and apparatus for converting coal to hydrocarbons by hydrogenation"
ABSTRACT OF THE DISCLOSURE
A method and apparatus for converting, i.e.
hydrogenating, dry particles of coal with hydrogen to give hydrocarbons such as engine or heating fuels. The invention combines together several steps in the hydro-genation process, such as compressing the dry coal , heat-ing, plasticising and hydrogenating, in one apparatus.
The apparatus comprises a housing, preferably a cylinder containing a feed and preparation portion of a chamber with a rotatable friction element therein and an imme-diately adjoining hydrogenation portion of the chamber with a rotating rotor therein and with static mixing nozzles projecting thereinto, through which nozzles heated hydrogen can be injected into the coal which has been brought, by the friction element into a heated, plastic state. The friction element and rotor can be driven by a single drive means, the feed and preparation portion of the chamber can be fed with coal from a hopper through a wheel lock and the hydrocarbon products can be ejected through a valve into a separator.

Description

11~2109 The inven-tion relates to a method and apparatus for converting, using hydrogen, c~al -to hydrocarbons by hydrogenation.
A broad field of prior art is known in respect of both methods and apparatus for converting coal to hydrocarbons by high pressure hydrogena-tion. Apparatus for high pressure hydrogenation usually operates by first producing a coal pulp comprising crushed coal and mixing oil. The pulp is fed to a pre-heater, after which it - 10 passes into a reactor together with the paste-forming oil or mixing oil, which is added only to enable the coal to be pumped. The reac-tion products thereafter pass into a hot separator and units which continue the process.
The main disadvantage of a coal hydrogenating plant of this kind is that the pre~heater, which usually comprises coils o~ piping embedded in a metal block and electrically heated, becomes clogged with coking products.
The previously proposed installations further comprise ma~y separate units interconnected -by pipe and valve syste~s. For this reason too a large arnount of trouble has to be expected in operation. The coal par-ticles mixed with a paste ~orming oll and ihe hydrogena-tion products themselves are at very high pressures, up to 500 ~ars, and high temperatures, up to 500C. I-t is obvious tha-tlmder such conditions products can cnly be conveycd from one ~mit to another by very ecpen~ive, specialised equipmcn-t.
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-11~2109 Other hydrogenation processes have baen proposed, operating withou-t any so-called paste forming or mixing oil. Published German specification 2 723 457, for example, describes a method ~nd apparatus for hydrogena-ting coal, starting with particles of dry coal. To enablea hydrogenation product to be obtained from dry particles of coal, however, an injector system on the rocket drive mechanisrn princip].e is us~d in this case. Many dis-advantages of prior art can indeed be avoided by using such a method and the appropriate reactor, but the in-stallation itself is extremely complicated and therefore very liable to trouble in operation and expensive in manu-facture, which means that the hydrogenation products pre-pared have to carry high costs.
The invention has among its objects to provide a method and apparatus for converting coal into hydrocarbons by hydrogerlation, whereby the steps of compressi.ng, heat-ing, plasticising and hydrogenating can be carried out in-expensively in one piece of apparatus.
The invention also aims to provide a method ard apparatus for converting, using hydrcgen, coal into hydro-- carbons ~rhich can be carxied out witlll dry coal particles, without the disadvantages of paste-forming oil, which appa-ratus can be constructed cheaply and be of coMpact form.
.Accordi~g to one aspec-t of the invention, there is provided a method of converling, using hydrogen, coal to hydrocarbons, comprising feeding dry part.icles of coal in . .

ll~LZ109 the fQrm o~ powder or pieees continuously into a chamber from a pressure-sealed volume-eontrolled dispenser, eom-pressing the partieles of eoal in the chamber and eon-tinuously converting them into a plastic state by fric-tional heat, subjecting the plastie eoal in the chamber to intensive motion and impinging upon i-t with hydrogen to cause distribution, dispersion and hydrogenation and ~eeding the plastic and gaseous hydrogenation prod,.lcts eontinuously to a hot separator.
According to another aspect of the invention9 there is provided apparatus for converting, using hydro- -gen, eoal to hydrocarbons, comprising a pressure-se~led volume-eontrolled dispenser, a chamber i.nto which dry particles of coal ean be fed from the dispenser, the ehamber eomprising a feed and preparation portion and a hydrogenation portion, a frietion elemen-t in -the feed and preparation portion of the eharnber to compress the eoal and eonvert it into a plastic state by frictional -.
heat and a rotor and static mixing nozzles in the hydro~
genation portion of the chamber.
By feeding dry par~icles of coal i.nto the feed : . and preparation portion of the chamber by means of -the pressure-sea].ed volume-eontrolled dispen.ser, an initial pressure ean be built up even in the feed and prep~.ration portion of the chamber, which initial pressure CaL1 con-siderably accelera-te the compressing process and -the -~ heating process by means of frictional heat~ The ~ .................................. .

ll~Z109 pressure is prevented from spreading from the feed and preparation portion of -the chamber to the dispenser.
Si.nce dry coal particles with a relatively high bulk weight can be fed in, the compressing of the par-ticles can provide a pre-requisite for the next step in the method, namely the h~ating by friction.
Intensive shearing, can cause internal friction ~f the individual particles of cpal resulting in rapid heating of the particles.
The quantity of frictional heat transferred to the coal depends on the geometrical formation of the fric-tion element and the induced drive power -transferred to the coal material ~y the rotating friction element. The faster the friction element turns the more rapidly the coal particles are converted to the plastic state and conveyed into the hydrogenation portion of the char~lber.
When the friction treatment applied to the com-pressed particles of coal enables the agglomerating or plasticising temperature to be reached (this may be from 350 - 450 C depending on the type of coal') the flu.id, - heated hydrogen is injected. This is accompanied by in-~ tensive eddyin~ of the plasticised coal, i.e. intensive distri.bu~ion and dispc-rsion or spreading ou'~.
~.'hen the heated hydrogen comes into contact with the higll--te-,nperature, plasticis~d cOal, hydrocarbons of diferent valenci.es will be formed according to the con-ditions c,f the process (pressure, tempera-tureS residence 11~2109 time)..in an exothermic reaction.
The fact that the ho-t hydrogen inJectc-d strikes the very finely distributed coal in motion and strikes the whole content o~ the hydrogenation portion of the chamber almost simultaneously can ensure extremely rapid conversion, i.e. hydrogenation, to hydrocarbon, and the appara-tus therefore can achieve a very high output.
The p]astic and ~aseous hydrogena-tion products can thereafter be fed continuously to a hot or cold ... .. .
separator and, according to thei.r character, are further processed into engine or heating fuel.
The feed and preparation portion of the chamber in which the dry coal particles are compressed is pre-ferably cylindrical and the rota-ting friction element exerts a conveying ac-tion and heats the coal to hydro-genating temperature by frictional heat. The material then passes into the hydrogenation portion of the chamber which is also ~referably cylindrical and adjoins the prepara-tion chamber without any transition..
-20 The hydrogenation portion of the chamber contains the rotating rotor, which rotor has vanes and is secured against relative rotation with respec-t to the friction element. The static mixing noz.zles are prefera~ly of different lengths and projec-t into the hydrogenation por-tion of the chamber, ensuring that the hydrogen will be ejected in different planes and thus uniformly throughou-t the volun-,e of tlle hydrogenation port..on of the chamber.
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11~21~9 The speed of hydrogenation and the output of the apparatus can be controlled dependent on the peripheral speed of the rotor and of the friction element connected thereto.
By providing the hydrogenating portion of the chamber and the feed and prepara-tion portion of the chamber in a single housing, it becomes possible to carry out the compressi.ng step, the heating process, the plasticising process and even the hydrogena-ting process in one piece of apparatus, thereby elimlinating many of the sources of trouble experienced in prior ar-t apparatus.
For example i-t is no longer necessary for the dry ccal particles to be pre-heated in a separate apparatus as in USA specification 3 030 297 and fed into a pipe by means of a further machine, namely a conveyor, and for the pre-heated carbon particles in the pipe to be further heated by heated hydrogen and conveyed into the pre heater. Since the heati.ng in the pre-heater and in the reactor, which can be ec~uated with the cham~er of this invention~ is carried out by means of coiled pipes which are -taken through in a helical or cage shaped arran~ement and to which heat is applied, -the danger of these coiled :: pipes, carrying the coal particles and hydrogenS coking up is particularly grea-t because heat.ing to hydrogenatir.g temperature is effected by heat conduction. Furtherlnore there 5 a dan~er of the valves and pipes beco~ g clngged.
In the appara-tus of this invention -the combination of the s-teps necessary for the hyclrogena-tion process ancl B
the processing conditions which become necessary, in one machine unit ~ccomrnodated in a single chamber~thus can avoid the aggravating disadvantages of prior art.
Since the apparatus can have a considerable out-put despite the appreciable reduction in the number ofpieces of apparatus, because a positive and controllable eddying speed for the coal with the hot hydrogen is pro-~uced in the hydrogenating chamber, i e. the reactor, the installation can be very economical.
Separate drives for the friction element and the rotor can be provided if desired in order that the re-spective peripheral speeds can be adapted to di~ferent grades of coal.
I~ two drives are used, it is possible to arrange ~5 the hydrogenation portion of the chamber at right angles to the feed and preparation portion of the chamber but with the two portions still in one housing.
Usin~ a friction element and a rotor turning in a cylinder can give a machine ~hich is very robust .. . .
and durable, less expensive and also less sub~ect to - trouble. This becomes particularly clear in a comparison - with the machines formerly employed for carrying out the c~mponeIl-t processes, such as mixing uni's, piston pumps and preliminary heaters which were very Jiable tc trouble.
Units rotating in cylinders &re far safer and more readily controlled from the engineering point of view.
The invention is diagrammatically illustrated by ll~Z109 way of example in the accompanying drawings, in which:
Figure 1 is a longitudina1. section through hydro-genating appara-tus according to the inven-tion, including a pressure-sealed feed hopper and a hot separator;
Figure 2 is a longitudinal section through part - of a feed and preparation portion and a hydrogenation por~
tion of a chamber of the apparatus of Figure 1 with a ~riction element and a rotor disposed therein;
Figure 3 is a longitudinal section through the 10 chamber end of a static mixing nozzle with non-return valves of the apparatus of Figures 1 and 2;
. Fib~re 4 is a cross-section taken on line IV-IV
of Figure 2, through the hydrogenati.on portion of the chamber5 the static mixing nozzles and the rotor;
Figure 5 is a longitudinal section through a different embodiment of a friction element for apparatus according to the invention;
Figure 6 and 7 show differen-t ~rrsngements of feed and preparations portions and hydrogenation portions of a chamber of appara.-tus according to the invention; and Figrure 8 is a fragmentary longitudinal section -- through a still further embodimen-t of apparatus accordi.ng to the invention.
Refexring to the drawings, and firstly to Figures 1 to 51 apparatvs for conver-tj.ng coa1 to h~-drocarbons ~.~ith hydrogen, comprises a pressure-seaJ.a~)].e :Feed hopper 1 which is closed at its top end by a valve 2. At the .. .. .

11~21~19 .

bottom end of the hopper 1 there is a cellular wheel lock 3 which shuts off the hopper 1 from a feed and prc-parati.on portion 4 of a chamber.
The feed and prepara-tion portion 4 is f'ormed by a cylinder 4a (Figure 2~ with temp~ring passages 5 extend-ing in a longitudinal or radial direction therein. A
circulating heating or cooling medium may be applied to +he passages 5 by means of a tempering system (not sho~m).
In the feed and preparation portion 4 there is a friction element 6 carrying friction webs 7 in a helical arrangement. The angle of the ~eb 7 i.e. the lead angle between a vert.ical and the axis of the friction element, is chosen according to the conveying speed desi.red.
The pitch width 7f, i.e. the spacing between ad-jacent friction webs 7, is chosen according to t,he size of the coal partic'es to ~e hydrogenate~ or to the v.-s-cosity of decomposed coal paste to be -used~ Xt is also possible to vary the p~.tch depth between the individual friction webs 7, ~ to allow for control of pressure in the feed and preparation por-tion 4 at the do~fnstream and thereof. As the pitch depth and pitcn wi.d-th 7f are - reduced there is an increa~ing build-up of pressure fl~c-m a pre.ssure build-up region 23 to a friction region 24 towards a h~,rdro~enation portj.on 9 of the chamoer.
rrhe frict.ion element 6 and a rotor ~, secured against -rotation with respect thereto and located in the hydrogenation portion 9 of the chamber are set in rotation ... .

ll~'Zl 1:19 by drive Tneans 10, which will not be described in de-tail.
Thc rotor 8 in the hydrogenation portion 9 has vanes 11 the.reon. These may be arranged obliquely to the axis o~ the rotor 8, to produce a conveying action in the chamber 9. Fi~ure 2 of the drawings sho~rs spoon-like vanes 11. However, the vanes could be constructed diffe-rently, ~ in the form of coiled ~ebs 11b on the ro-tor 8, which are interrupted at positions 11c, where ~tatic mixing nozzles 12 project into the por-tion 9 of the chamberO
r~he hydrogenation portion ~ is formed by a cylin-der 13 ~rhiGh has integral tempering passages 14. ~he passages 14 may extend around the cylinder 13 in a radial direction or may extend axiall~. h temperin~ system which ~rill not be further explained is connec-ted to the passages 1/~. This systeJn allows for steplessly adjustable ternpering, that is to say, for heating -the cy.Linder 13 ~rhen the ins-tallation is being started -up and for cooling it during subsequent operation.
The static mixin~ no~71es 12 project into -the hydrogena-tion portion 9 and ~ul~il -two func-tions. The : nozz].es 12 are disposed be-ttreen the rotor vanes 11 in ~uch a w~y that they reach the rotor ~. The vanes 11 im-part a conveying movement to the materi.al, ~r}lich is thus acted ~pon by the lol. o~!irg ~o~;r o r st~-tic Tr.ix~ing, noz~les 12 and sub;jected to i.nt(llsive mi.Y~in~ and eddying.
succee(ling row 11 of vanes then plclc~c up the streaTn o .

il.~2~:)9 material, and the intensive mixing and shearing move-ments are repeated.
~ n addition to their mixing func-tion the nozzles 12 have -the function of feeding hydrogen to the portion 9 of the chamber. Thus passages 15 (Figures 3 and 4) are provided .in the ~ozzles 12, the passages 15 being closed at the end and also a-t the side half way along the length by non-return valves 16 and being connected to a 'rydrogen supply s~stem 17. The system 17 is connected to a com-pressor 18 and a hydrogen source 18a, whereby hydrogenis forced in-to the portion 9 of the chamber under pres-sure.
The portion 9 is closed at its downstream and by a vaIve 19 ~hich opcns when a pre-selec1;ed pressure is exceeded. ~hen the hydrogenation products have passed through ~he valve 19 they enter a hot separator 20, which can be closed by means ol valves 21 and 22.
The operation of the apparatus for converting coal into hydrocarbons with hydrogen, will now be des-~0 cribed.
Coal is fed in-to the hopper 1 in the form of pow-der or pieces. The valve 2 in the hopper is closed and pressure builds up. The coal in powdcr or piece form passes into the feed and prepara-tion por-tion 4 through ~5 the cel:lul~r wheel lock ~. Care must of course be taken to ensure -that bridges do not form in the h~pper 1 and cause troub]e. For this purpose agitating elements (not . .

1~2109 shown) are preferably fitted in the hopper 1 to keep the contents of the hopper 1 constantly in motion. To allow for continuous operation a second fee~ hopper can be provided, its valves and feed to the feed and prepara-tion portion 4 being switched over when the first hopperhas been emptied.
~ he cellular wheel lock ~ enables controlled quantities of the pieces of coal to be ~ed into t~e feed and prepara-tion portlon 4 of -the chamber. At the same +ime it ensures that the pressure prevailing in the feed ~ortion 4 cannot spread into the hopper 1.
- In the feed portion 4, which is divided into two regions, namely the pressure build--up re~ion 23 and the friction region 2L~, the coal is moved towards the hydIo-~5 genation por-tion 9 of the chamber by the rotating fric-tion element 6. ~he material is constantly compressed by the friction ~ebs on the fric-tion elemen-t 6, which webs define a passage bet~Jeen them. The rotating movement of the element 6 conveys -the pieces of coal by means oî the conveying side faces of the webs 7 towards the hydro-genation portion 9. The coal particles are thus subjected to a shearing movemen-t by -the webs 7, thereby g~nerating frictional heat and increasingly agglomerating them.
The particles pass from their powder or piece form into an aggloinerated state and from -there into â pl astic state as a result of the increasing shearing action.
The f~rictional elemen-t 6 is preferably constructed 11421~)9 as des,cribed below and shown in ~l~ure 5. In the pres-sure build-up region 23 the friction webs 7 may have a pocket-like undercut 7a, to allo~ for conveying Wi thou t great friction losses and thus for a build-up of pressure in the direction of arrow 7d.
The webs 7 provided with undercuts 7a extend approximate],y into the region where adequate pressure is reached in the feed and preparation portion of thc chamber 9 and into the region where the aggrega-te state of the coal ' 10 is converted into paste form or into a plastic phase.
In the friction region 24 the webs 7 may be pro-vided with inclined portions 7b and 7c on both sidesS so that they proponderantly exert a rubbing action on the coal particles or on the plastic phase of the coal.
The rubbing action of the inclined por-tions 7b an(i 7c generates considerable frictional hea~ to raise the temperature of the coal in paste or plastic form.
It is also impor^tant that, once the coal has be- , come pasty or plastic, i-t should adhere to the inner wall ... . .
of the cylinder 4a an~l be removed therefrom by the rota-ting movement of the friction element 6, through -the conveyin~ action of the web sides 7a, 7b In this way a large amount of frictional heat is transferred to the coal, thereb~- aiding in rapid and very strong internal heatin~ ' The conversion of the ag~rega-te si;a-te of the coa:L
from the piece or powder form -to -the plas-tic form is . ".

assis-ted during a star-ting-up phase of the ins-tallation - by heating the cylinder 4a of the portion 4 by means of a tempering medium which circulates n the tempering pas-sages 5. This enables the installation to be brought rapidly to its operating temperature.
To accelerate the hydrogenation process hydrogen may be fed into the coal even at the end of the feed and preparation portion 4. ~he coal will be plastic by -then and be at a temperature of approximately 400C and a pressure of approximàtely 400 bars. For this purpose static mixing nozzles 12a, fitted ~rith a non-return valve, extend through the wall of the cylinder 4a. The nozzles 'l2a com;nunicate with a hydrogen supply system 17 connected to the compressor 18 and the hydrogen source 18a.
The plas-tic coal, already enriched with hydrogen and brought to a high temperature in the feed and prepara-tion portion 4, is passed into the hydrogenation portion 9 by the conveying action of the friction webs 7. In the portion 9 it is subjected to an intensive mi~ing and shearing acti~n by the rotor vanes 11 and the sta-tic mix-ing nozzles 12 disposed bet~een the vanes.
Referring now to Figure 4, eight vanes 11 are provided on the rotor 8 disposed around its periphery.
This number may be increased or leduced depending upon the length and efficiency of -the hydrogenation portion of the cha~nber.
The hvdrogen, which is put under very high pressu~e :

ll~Z109 by the compressor 18, is injected into the portion 9 through all the mixing nozzles 12 simul-taneously. The fact that the no~zles project di~ferellt distances in-to the portion 9 enables the hydrogen to be injected at many places simultaneously and almos-t centrally into the portion 9. This allows the hydrogen and plastic coal to be intensively and evenly distributed and dispersed ~llroughollt the whole volume of th~ portion 9, and results - in extremely intensive and rapid hydrogenation.
In this connection the term "distribution" refers to mixing of the various components, while the term "dlspersion" is used to describe the separation of in-dividual coal particles by rubbing. The dispersion considerab1y accelerates the spli-tting up of agglomerated parts of -the coal and thus the hydrogenation process~
The dispersion and spreading out of the contents of the hydrogenation chamber take place primarily on the imler wall of the cylinder 13.
Since the hydrogenation portion 9 of the chamber is also surrounded by the radial or axial tempering pas-sages 14, additional heat can be supplied from outside -- while th~ installation is in i-ts star-ting phase. The passages 14 are oonnected to tempering sy~tetns (not showr.) which provide a circulating tempering action.
Since the hydrogerlation reaction in the chamber ~3 is exothermic, the tempering passages 14 are switched over when the starting-up tlme for the installation s ~142109 over, and are used as cooling passages with a circulating cooling medium to dissipate the heat.
A very high pressure of up to 500 bars is main-tained in the feed and preparation portion 4 and in the hydrogenation portion 9. Care must therefore be taken to ensure that the outle-t of the portion 9 can be pressure-sealed by means of the valve 19 which will open when a preselected pressure is exceeded. When the hydro.~enation products have passed through the valve 19 they enter the hot separator 20, which separates solid from liquid pro-ducts. The hydrogenation products then undergo fur-ther processing in -the usual, known manner.
To enable the friction element 6 in the feed and.
preparation portion 4 and the rotor ~ in the hydrogena-tion portion 9 to be driven at di.fferen-t speeds, the arrangement shown in Figure 6 can be used, where the por--tions 4 and 9 are accommodated in a common housing bu.t the drive 10 drives only the friction elemen-t 6 and a separate drive 10a drives the rotor 8. The fric-tion element 6 and -the rotor 8 are either engaged one w.~hin - the other at their position of con-tact or run freeiy centered in the respec-tive cylinders 4a and 13~ The speed dlffexence is advantageous for hydrogenatin~ charge coal wi-th di:.ferent properties and hydrocarbon content.
Figure 7 sho~s an installation ri~th a vertical hydrogenati.on pcrtion 9. In this arrangeïl1en-t -the fric-tion element in the feed and preparation por-tion 4 drives ll~Z109 the rotor in the hydrogenation portion 9 by means of the bevel gearing 28 indicated. The rotor in the hydro-genation portion 9 is mounted at its ends in bearings 29 and 30. Such a disposition of the hydrogenation portion 9 and the feed and preparation portion 4 can take up very little space and be particularly advantageous in certain cases.
Figure 8 shows an embodiment where the po~tions 9 and 4, arranged in a common housing, are of the same diameter. The advantage of such an embodiment is that a cylinder extending right through the appara-tus can be used, this being simpler and cheaper to manu~acture than a stepped cylinder.
Providin~ the internal diamel;er of` the cylinder 1~ of the portion 9 twice as large as that of the cylinder 4a of the portion 4 has the advantage -that the volume in the hydrogenation portio~ can be up to our times as great, so that the hydrogenating performance in a given time can be ~uadrupled. However, if the diameters of the ~0 portions 4 and 9 are equal as in Figure 8, i-t is desirable for the diameter of the shaft of the rotor 8 -to be re-duced accordingly, in order to have more volume available for carrying out the hydrogenation process. In a pre-ferred embodiment the diame-ter of the shaf-t of t;he rotor ~5 8 in such a case is chosen to be do~.-n to half the diameter of the shaft of the friction element 6. ~he shaft diameter is undelstood as being the diameter measured , 1~42109 without the rotor vanes 11 and without the l~rebs 7 on the ~ric tion element 6.

Claims (18)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of converting, using hydrogen, coal to hydrocarbons, comprising feeding dry particles of coal continuously into a chamber from a pressure-sealed volume-controlled dispenser, compressing the particles of coal in said chamber and continuously converting them into a plastic state by frictional heat, subjecting the plastic coal in said chamber to intensive motion and impinging upon it with hydrogen to cause distribution, dispersion and hydrogenation and feeding the plastic and gaseous hydrogenation products continuously to a hot separator.

2. Apparatus for converting, using hydrogen, coal to hydrocarbons, comprising a pressure-sealed volume-controlled dispenser, a chamber into which dry particles of coal can be fed from said dispenser, said chamber comprising a feed and preparation portion and a hydrogenation portion, a friction element in said feed and preparation portion of said chamber to compress the coal and convert it into a plastic state by frictional heat and, in said hydrogena-tion portion of said chamber, a rotor and static mixing nozzles for introducing hydrogen into said hydrogenation portion of said chamber.

3. Apparatus as claimed in claim 2, wherein said chamber comprising said feed and preparation portion and said hydrogenating portion is defined by a cylinder.

4. Apparatus as claimed in claim 3, wherein a cellular wheel lock is provided to control feed of coal through a feed aperture into said chamber from said dispenser, said dispenser is formed as a pressure-sealed feed hopper, said friction element has friction webs thereon; said rotor has vanes thereon, said hydrogenation portion of said cham-ber adjoins said feed and preparation portion of said chamber without any transition; said cylinder of said chamber and said rotor are constructed so that they can be tempered; said static mixing nozzles extend through the wall of said cylinder of said hydrogenation portion of said chamber, point towards the axis of said rotor, pass through said cylinder in radial and axial directions at equal spacings, can be closed by non-return valves and communicate with a source of hydrogen under pressure; and an outlet from said hydrogenation portion of said chamber can be closed by a valve which opens at a preselected pressure.

5. Apparatus as claimed in claim 4, wherein said rotor vanes are formed by helical friction webs extending around said rotor and interrupted at dipping positions for said mixing nozzles.

6. Apparatus as claimed in claim 4, wherein the dipping depth of said mixing nozzles through said cylinder varies.

7. Apparatus as claimed in claim 3, wherein the in-ternal diameter of said cylinder of said hydrogenation portion of said chamber is up to twice as large as that of said feed and preparation portion of said chamber.

8. Apparatus as claimed in claim 3, wherein the dia-meters of said cylindrical hydrogenation portion of said chamber and said cylindrical feed and preparation portion of said chamber are equal, and the diameter of the shaft of said rotor is down to half that of the shaft of said friction element.

9. Apparatus as claimed in claim 2, wherein said friction element and said rotor are secured against re-lative rotation, can be driven together by drive means and the speed of rotation thereof can be set in a step-lessly adjustable manner.

10. Apparatus as claimed in claim 2, wherein said friction element and said rotor are each equipped with separate drive means.

11. Apparatus as claimed in claim 10, wherein the speed of rotation of said friction element and of said rotor can be set so that they are different.

12. Apparatus as claimed in claim 5, wherein said friction element is constructed with said friction webs thereof of varying pitch.

13. Apparatus as claimed in claim 5, wherein a passage formed between said friction webs on said friction ele-ment decreases in cross-section to obtain an increase in pressure in the coal in a direction towards said hydro-genaiion portion of said chamber.

14. Apparatus as claimed in claim 5, wherein in a pressure build-up region of said friction element the sides of said friction webs which have a conveying action are constructed with a pocket-like undercut to generate pressure and in a friction region said webs are constructed with inclined portions to generate frictional heat.

15, Apparatus as claimed in claim 4, wherein axially or helically extending slots of varying depth and pitch are provided in the inner wall of said cylinder in a pressure build-up region of said feed and preparation portion of said chamber and below said feed aperture.

16. Apparatus as claimed in claim 3, wherein said cylinder and said friction element are constructed so that they can be tempered, the cylinder by means of tempering passages therein and the friction element by means of an axially extending tempering passage with an adjoining tempering system.

17. Apparatus as claimed in claim 2, further com-prising feed apertures, for injecting hydrogen, located in said feed and preparation portion of said chamber.

18. Apparatus as claimed in claim 27 wherein said hydrogenation portion of said chamber is disposed with its axis extending at right angles to the axis of said feed and preparation portion of said chamber and said rotor is mounted and driven by said friction element by means of a bevel gearing.