US1944749A - Carbonization apparatus - Google Patents

Description

1929 3 Sheets-Sheet l H. O. LOEBELL CARBONIZATION APPARATUS `ian. 23, 1934.

Filed March 18,

xk/PX" Jan. 23, 1934. H. o. LOEBELL CARBONIZATION APPARATUS Filed March 18, 1929 3 Sheets-Sheet 2 32712* his @Home/1g Jan. 23, 1934.

H. o. oEBE| f CARBONIZATION APPARATUS Filed March 18, 1929 5 Sheets-Sheet 5 Smau/Lto@ HENRY O. uoBELl.

' @513 his @Hof/nw Patented Jan. 23, 1934 UNITED STATES 1,944,749 cAnBoNIzA'TIoN APPARATUS Henry 0. Loebell, Malba, Long Island, N. Y., assignor 'to Henry L. Doherty, New York,

`Application March 18 1929. Serial No. 347,802' 19 claims. (o1. 2oz- 22) 'I'his invention relates to an apparatus for carbonizingbituminous materials in thin layers, and it is of special. utility in connection with the low-temperature distillation of coking coal and similar carbonaceous materials or mixtures there- 0f. in which the partially or completely carbonized materials are subjected to a'briquetting operation during or subsequent to the carbonization step.

In the past many attempts have been made to carbonize bituminous fuel and the like in relatively thin layers owing to the many economies recognized as theoretically possible due tov such factors as the sp'eed at which the material can 'be heated to the carbonization temperature. Such processes heretofore known have been practically limited however with regard to the thickness of the fuel layer that could be processed in apparatus in use prior to the present discovery. The invention is the result of an extensive investigation planned to determine the potential commercial possibilities of a processof rapidly carbonizing bituminous fuel in very thin layers, particularly when employing temperatures in' the low temperature carbonization range.y The discovery has now been made and ve'ried that the rate of carbonization,-particularly when `employing temperatures within the usual low-temperature carbonization range,-is proportional to the square of the thickness .of the layer of coal being carbonized; this means that a coal layer 1" thick when heated to a given temperature will carbonize in l1th the time required under similar conditions for carbonizing a 2 layer.

In the past the manufacture of coke by the carbonization of coal and the like in thin vunconned layers has not yielded entirely satisfactory productsdue to the fact that in such thin layers an apparent surface swelling of the coal layer occurs evidently due to the retention in the said layer of bubbles. of the distillation gases passing through the plastic layer of coal. This resuits in the production of a light porous coke which is unsuitable for many applications, such' asfor domestic fuel, metallurgical purposes, and the like. As the thickness of the layer of material t'o be carbonized decreases, the above mentioned swelling effect becomes more pronounced, and the specific gravity of the carbonized product-decreases. While. the rate of coalcarbonization may be increased also by raising the temperature at which the carbonization is effected,"

(since itris vnowflk'nown that the rate of carboniz'ation isroughly proportional to the E.4th power of the absolut'e temperature employed),

yet ythe application of this method of increasing the carbonization rate is limited in practice by the difficulty and expense of securing structural materials which will possess suitable strength at temperatures much in excess ofl000 to 1200 60 F., which are normally necessary to an economic carbonization operation-as well as by the undesirable eiects upon the physical properties pf the final carbonizped product and upon the liquid and gaseous by-products obtained when too high temperatures are employed yfor the carbonization.

` It is now generally recognized that it is possible to produce a carbonized product having a satisfactory coke structure if the material-being carbonized is held substantially stationary within a confined space betweenwalls durngihe carbonizationl However, standard processes such as those commonly carried out in by-product coke ovens and in vertical xetorts and similar units are not suitable for carbol izing in very thin lay,- ers because of themechanical ditliculties involved in charging thin layers of finely divided bituminous materials into these retorts due to frictional diiliculties and because of diilculty in later discharging the thin layers of carbonized material therefrom due to the cementing action of the bituminous content of the material which not only prevents the satisfactory discharge of th'e thin coke layers but which also facilitates Inechanical Idestruction o f the coke structure and .l

materially limits the output of such a carbonizing unit. Present known processes in which coal is forced into .the retorts under pressure'A prior Ato the carbonization thereof are not suitable for use in treating very thin layers of -material norl for the production of a dense coke product because of the aforesaid objectionable features.

The present invention is based on the discovery that it is possible to rapidly carbonize bituminousv fuels 'and the like and to produce a dense carbonized product of satisfactory character by\ confining the bituminous material such as coal or coal-coke mixtures or'the like,.in thin layers, preferably 2" or less in thickness, between confining walls which,while' free to move toward each other as the carbonization proceeds, are adapted for exerting a determinate adjustable pressure continuously upon the opposite surfaces of the layer of coal during carbonization, while holding .the various particles of the coal in the layer in the 'same relative position with respect to each other throughout the 'carbonizatiom so that a uniform cell structure will be developed in the coke, or other carbonized product, and the 11g coal gas simultaneously formed will havea high B.t. u. value. By pressing the thin layer of fuel during the said carbonization against a suitably shaped surface, the said fuel layer may be simultaneously carborized and formed into briquettes of suitable density and other physical characteristics for use as domestic fuel and the like. 2

Among the chief objects of the invention are to provide an improved method and apparatus for continuously producing coke or other carbonized product of relatively high density from bituminous materials such as coal; -to provide in an improved manner for rapidly carbonizing coal and the like in thin layers while holding it under a determinate range of pressures; to provide in an improved manner for carbonizing coal in thin vlayers vrwhile holding the coal stationary and forming a carbonized product having a uniform cell structure suitable for rdomestic fuel and the like; to provide in a carbonizing process and apparatus therefor for maintaining a predetermined range of pressures upon a thin layer of the material being carbonized irrespective of any change occurring in the thickness of the layer during the carbonization; and to provide in an improved manner for carbonizing bituminous material and the like in a thin layer while under pressure, and concurrently forming the thin layer into a plurality of briquettes and discharging the carbonized material in such form. f

The present invention broadly may be said to reside in the partial or complete carbonization,

preferably within the low temperature carbonization range, of bituminous material such as bituminous coal or mixtures thereof with coke or other suitable material preferably in finely-divided form while it is held in a thin confined layer,l the carbonization being affected by the application of heat to either or both sides of the layer,

and maintaining on the said layer a determinate pressure during part or all of the period of carbonization. I'he invention further contemplates the simultaneous carbonizing and briquetting of coal and the like in thin layers while under pressure, and it provides novel means for supplying the necessary heat for the carbonization and for continuously .charging the carbonaceous material into the carbonizing zone, as well as for removing the carbonized materialjfrom that zone after carbonization has occurred-and for removing during the carbonization the distillation gases and vapors as they are formed, and for subsequently condensing and recovering the latter.

In the accompanying drawings which show a preferred form of apparatus for carrying out the invention:

Fig. 1 is a cross-section of a preferred form of the carbonizing and briquetting apparatus taken on the line 1-1 of Fig. 2, parts being broken away;

Fig. 2 is a vertical cross-section of the said apparatus taken on the line 2-2 of Fig. 1;

Fig. 3 is a vertical cross-section taken transversely through a portion of the rotor showing a portion of the link conveyor, parts being broken away;

Fig. 4 is a perspective view 'of one of the conveyor links;

Fig. 5 is a plan view looking downward upon portions of the upper reach of the link conveyor and associatedrotor," parts beingbroken away;

Fig. 6 is a vetical cross-section through a portion of the rotor and associated vpfrtions of -the link conveyor, looking in the direction of the arrows in Fig. 3; and

, An annular ring gear 25 is secured to the rotor at Figs. 7 and 8 are, vertical sections taken through a pressing roll and means for its adjustment. l

Referring more particularly to the drawings, numeral 11 designates a horizontally-disposed, closed retort having end walls 12 and 13 and side j walls 14 and 15, the said retort being provided with the necessary top and base member and being suitably lined with refractory material such as-silocel. The said 'side and end walls of the retort form with the closed top and base thereof a closed carbonizing chamber. A hollow, rotatable, cylindrical drum or rotor 16 having a smooth external surface extends transversely through the retort, with its middle portion within the same and its respective ends extending through the opposite side Walls 14-15 thereof. The rotor 16 is rotatably supported at its respective ends on pairs of suitably journalled aligned rollers l 7-l7 18--18, which co-act with respective annular tracks or runner rings 19-20, mounted on lthe external surface of the rotor. Annular stuifing boxes 23-24 carried by the rotor are provided with suitable heat-resistant packing material such as asbestos fibre, and serve to prevent escape of volatile carbonization products from the interior of the carbonizing chamber around the portions of the rotor extending through the side walls of the retort during rotation of the rotor.

one end thereof and is adapted to mesh with a spur gear 26, mounted upon a shaft 27 connected to a suitable source of power for operating the rotor 16 at the desired speed in the direction of the arrow in Fig. 2. Any suitable reduction gear device for adjusting the .speed of the shaft 27 may be interposed between the latter and the source of power. Suitable refractory end linings 28-29 are provided within the rotor adjacent the respective ends thereof.

For internally heating the rotor 16 ,a pair of concentric open-ended pipes 30-31 extend axially into the rotor from an outside point adjacent one end thereof and to a point within andadjacent the opposite end of the rotor, The inner 12p pipe 30 is connected to a source of combustible Aed to a flue 35 for the removal of combustion gases from the interior of the rotor. A circular 13,4- baille plate 36 of substantially smaller diameter k than the rotor is centrally secured to the cylindrical surface of the rotor adjacent to the gas outlet 34 by a plurality of radially-disposed supporting legs 37, 37. The pipes 30-31 are sup- 135 ported axially of the rotor near their open ends by a suitable spider 38 of heat resistant metal or the like the legs of which are suitably secured to the inner surface of the rotor. A hollow frustoconical baflle member 39, is mounted on the pipe 34g 31 with its smaller end secured to the spider 38. f The member 39 extends outwardly therefrom so as to have its larger end disposed near but spaced from the cylindrical surface of the rotor, the arrangement being such 'that the hot gases formed 14.5 bythe combustion occuring within the rotor adjacent the open ends of the pipes 30, 3l, will be forced to flow toward the cylindrical surface of the rotor as the said hot gases move toward the gas oiftake 34, while at the same time permitting 15C forces these combustion gases to ii'ow at that' point close to the cylindrical surface of the rotor, while at the same time increasing the velocity of flow of the said gases by decreasing the crosssectional area of the space through-Which the now of gases occurs. This tends to effect a uniform distribution along the cylindrical surface of the rotor of the heat developed by the combustion initiated at one end thereof. An elongated horizontally disposed idler roll 41 generally of somewhat smaller diameter than the rotor 16 is rotatably mounted, in the end of the retort opposite the end housing the rotor, upon a shaft 42 arranged parallel to the axis of the rotor, the shaft being carried in respective end-bearings 43-43 slidable in journals 44 for movement in a direction toward and away from the rotor. The idler roll 41 employed may be either larger than, of substantially the same size, or smaller than the rotor. Each of the bearings "43-43, is provided with a horizontally-disposed rod portion 45 extending through an apertured bushing 46 in the end wall 13 of the retort, and having the outer end thereof threaded for accommodating a nut 47. A compression spring 48 is mounted o'n each rod 45 and is operatively interposed between the corresponding bushing 46 and a -washer or collar 49,-being secured in such position by the nut 47. The arrangement is such that threading the nut 47 along the rod changes the degree of compression in the spring and causes sliding movement of the rod through the aperture in the bushing 46 so as to move the idler roll 4l toward or away from the rotor. The idler roll is providedv with en d plates 50-50 which constitute flanges at the extremities thereof. A

For conveying a thin layer of fuel to` be carbonized to the surface of the heated rotor` and for securely holding the fuel against the said rotor surface during the carbonization of the former, an endless conveying belt of heat resistant material such as the flexible woven wire belt 51 is disposed so as to encircle the rotor 16 and to contact with fuel carried upon the mid-portion thereof within the carbonizing chamber, and also to encircle the mid-portion of the idler roll 4l,-

the construction 'of the idler roll and the associated adjustable parts permitting the idler roll to function as a belt tightener to vary the tension .upon the endless belt and to thus vary the resultant pressure that the belt exerts upon the fuel carried thereby between it and the portion of the rotor with which the fuel contacts.` A pair of spaced, annular angle iron anges 40 are secured at opposite sides of the mid-portion of the rotor surface Within the retort and serve as guides for the respective side edges of the endless belt 51.

For heating the carbonizing chamber through the external walls of the latter, andfor causing a flow of heat to portions of the belt and the coal carried thereby in a direction opposite to the direction of the heat flow thereto from the rotor, a heating jacket 52 is provided within the end wall 12 and portions of the top and base. 'I'he jacket 52 is provided with means for introducing thereinto a combustible gas and air, and additional means for removing combustion gases therefrom, the former comprising a pair of concentrically-arran-ged, valve-controlled pipes 53-54 respectively connected with a source of combustible gas and with a source of air under pressure; and the latter comprising a gas oiftake 55 located near the top of the retort and leading to a stack or some suitable type of heat exchanger or economizer (not shown).

For distributing material to be carbonized upon the belt conveyor, a coal conveyor trough 56 having a longitudinal slot or opening 57 in its bottom extends into the retort through one side thereof and is arranged parallel to the rotor. The bottom of the trough 56 is positioned a short distance above the lower reach of the conveyor belt 51 at a point adjacent the lower external surface of the 51 across the entire' width of the said belt,-through the said opening in the bottom of the trough 56.

Suitable provisions may be readily made as by f means of a vertically adjustable scraper 58 for adjusting the depth of the coal layer so that it either may be distributed in a uniform layer across the entire width of the belt or so that a greater depth of fuel may be maintained adjacent one side of the belt than adjacent the other side thereof. For supporting the lower reach of the flexible belt at and near the point at which the coal layer is deposited thereon, a plurality of idler rolls 594-59 are provided, the latter being mounted either individually or as a unit in such manner as to be readily adjustable vertically for facilitating the adjustment of the-thickness of the coal layer to be carbonized. The trough 56 isl provided with the usual type of conveying screw or other conveying means, and with a feeding hopper or the like 56a at the feed end. The escape lof distillation gases through the hopper 56a may nol the rotor betweenthe latter and the idler roll 41 so as to `lie beneath -the upper reach of the conveyor belt. The trough 61 has one of its sides 61al extended and curved laterally so yas to lie closely adjacent yto or in contact with the adjacent external surface of the rotor and adapted to act as a scraping or d ivertingmeans whereby the coke is scraped from the surface cf the rotorl and directed into the trough 61'. Ascrew conveyor or the like 62 operates within the trough 61 and serves to carry the carbonized materials deposited therein out of the carbonizing' chamber to a closed chute 63 for discharge into an air lock chamber (not shown) from thence it may be conducted toa cooler or to another suitable point of discharge. For facilitating the discharge of the carbonized materialV from the endless conveying belt 51 after the latter passes from contact with the rotor, and for directing the thus discharged material nto the trough 61, an idler roll 65 is mounted upon a transverse shaft supported at its ends in the side walls 14, 15- of the retort shown)l for eiecting the withdrawal from the said chamber of the' distillation gases fand vapors formed during the carbon'ization, 'under' either atmospheric pressure or vacuum'and for leading them to the usual train of scrubbers and coolers and to storage. y

With the arrangement of parts as shown in Figs. 1 and 2, it will be'observed that the pressure exerted upon the fuel layer gradually increases during the first or early stages of the carbonization, finally reaching a maximum, after which the pressure upon the partially carbonized la'yer gradually decreases during the final stages of the carbonization and is relieved adjacent the point of discharge of the carbonized product from the rotor. It is within the scope of the invention to construct the rotorand the idler roll 41 in xed relationship with respect to each otherand to have adjustable the roll 65 so as to permit it to function as a belt tightener for the purpose of developing the pressure upon the fuel layer being carbonized. In thislatter instance, the pressure exerted upon the fuel layer will be gradually incased during the 'course of the carbonization, reaching a maximum just prior to the discharge of the carbonized material from the rotor. The roll 65 may be rendered adjustable in any well known manner, such as that illustrated in Fig. 7 in which the roll is supported at its ends by members 80, each vertically adjustable by a threaded regulating member 82 carried by the retort top and extending through a boss 84 thereon. Each member 82 is adapted to regulate the compression of a spring 86 positioned between a corresponding boss 84 and a bearing surface at the upper end of member 80 and to regulate the longitudinal movement of the corresponding member 80. A lock nut 88 serves to lock the members 8". in any selected position. A lock nut 90 also is provided. A lighter compression spring 92 serves to limit the downward movement of each supporting member 80. In any case, the effective pressure upon the curved fuellayer being carbonized is applied in a radial direction with respect thereto and unidirectional with respect to the flow of carbonizing heat to the said layer.

When it is desired to simultaneously carbonize and briquette bituminous material, the flexible woven wire belt above described is replaced by an endless link belt of heat-resistant metal such y for example, as that shown in Figs. 3 to 6. The

` smooth surfaced rotor is also preferably replaced by one having annular Wedge-shaped ribs at suitably spaced intervals along its external surface. Referring to Figures 3 to 6, the endless conveyor is composed of a plurality of links, each having a tongue end portion 66 and, opposite thereto, a yoke or forked end comprising a pair of transversely spaced apart, parallel members 67, 67, the

said ends 66, 67, being separated by a verticaldisposed transverse rib or partition 68.

Each of Athe said links has an aperture 69 ex-I tending therethrough ,at a suitably reinforced middle portion of the tongue-end 66; and each link is provided also with a pair of aligned, transverse apertures 70, 70 extending through reinforced middle portions of each forked- end 67, 67 thereof, the said apertures 69, 70, 70., being preferably provided with heat- resistant metal bushings 71, 71, and being adaptedI to accommodate transverse tie rods or pivot pins 72, 72 for pivotal'movement with respect to the latter. The said links are associated together in such manner that-'the tongue end 66 of one link extends into the space" between the forked end portion 67, 67 of the next adjacent link, andthe thus-arranged linksare' pivotally connected by a 'pin 72 which passes through the respective tongue-end of one link and the forked-ends of the other link. The pins 72 are of sufficient length to accommodate a plurality of transversely-aligned links and to extend entirely across the width of the conveyor belt, although to facilitatethe making of belt repairs and of link replacement,when such is necessary,-it is preferable that a lesser number of links be mounted on each'of the pins 72 in the mannerdescribed. An assembly that is very satisfactory is one having six transversely-interasse# ciated links. The upper margin at each end of each link is preferably rounded as shown respectively at 73 and 74, and the upper margin of each of the forked- end members 67, 67 of each link extends above the level of the upper surface of the tongue 66, but below the level of the upper surface of the transverse rib 68. A portion of the upper surface of each of the former is bevelled as at 75, with the bevelled portions sloping downwardly toward each other, the angle of slope'preferably being such that the upper inner margin of each member 67 is of substantially the same height abovethe apertures 69', 70, as the upper surface of the tongue 66. The transverse rib 68, of each link preferably extends for a substantial distance above the'upper marginal portion of the members 67, and lis slightly wedge-shaped in cross section, with its upper margin transversely arched or curved as shown at 76.

For co-.operating with this link type of conveyor for shaping briquettes, the external sur face of the rotor 16 is provided with a plurality of annular projecting ribs or fins 77, generally wedge-shaped in cross section, the said ribs 77 being spaced apart along the rotor a distance approximately equal to or slightly greater than the transverse width of the individual links. The tapered or wedge-shaped sides of these ribs are adapted to co-operate with the arched side mar- -gins of the transverse ribs 68 and vwith the upper surface of. the forked members 67, 67, of each link and to exert a Wedging pressure upon a body of bituminous material enclosed thereby and supported upon the tongue portion of each' link 66.

When the links are grouped together upon the tie bars 72 in the manner shown and described,

vthe tongue portions 66 of each link is adapted to so-operate with and lie between the forked ends 6-7, 67, of another link with the said forked ends pivotally mounted upon the same pivot pin 72 so as to dene a shallow open-topped recep# tacle, the walls of which comprise the adjacent nally and transversely-intcr-connected series of shallow pockets or receptacles adapted to carry material to be carbonized into contact with the rotor. During such Contact a predetermined ypressure is exerted upon-the bituminous mate#r rial lying between the series of annular -rib's77f of the rotor, the upper margins of the transverse ribs 68, and the forked end members 67, 67, diie to tension ofthe belt induced by the compression spring 48 co-operating with the idler roll 41. Thisbelt tension results in awedging pressure generally directed `inwardly toward the mid-r die of the charge of material carried between two adjacent ribs 68 and two annular ribs 77, which wedging effect continues during contact of the material with the highly heated rotor.

The construction of the link assembly and inter-associated parts is such that after the belt with the material carried thereby passes from contact with the hot surface of the rotor, a slight reverse curvature is produced in the belt as the latter subsequently passes into contact with the idler roll 65 whereby the individual links there- 0f swing about their pivot pins 72. 'I'he member 64 forming the bottom of each coke-containing receptacle thus affected lpivots about its pin 72 and functions as an ejector, forcing the briquette outward away from the eonning walls, and facilitating the prompt removal of the finished briquettes from the conveyor and the discharge thereof into the receiving trough 61.

It is within the scope of the invention to dispense with the idler Aroll 65 in some instances, and-to effect the desired reverse curvature of the belt and resultant discharge of carbonized material therefrom by providing for a'suitable sag in the belt as it breaks contact with the rotor.

Although according to a' preferred modification of the invention a rotor having annular ribs upon its external surface is employed when bituminous. materials are to be simultaneously carbonized and briquetted, it is within the scope 0f the present invention to employ for this purpose a grooved or pocketedrotor in co-operation with a smooth-surfaced metal belt or woven wire belt,-or to employ a smooth-surfaced` rotor adapted to co-operate with a link belt or sheet metal belt having therein corrugations, cup-shaped depressions, or equivalent configurations, to act in the capacity of material-receiving and briquette-forming receptacles. It is desirable to supercharge the bituminous material upon the conveyor in order to facilitate the securing of the desired pressure upon the said material during the carbonization thereof.

In carrying out the carbonization of material in thin layers according to the preferred form of my invention, powdered coal or other finely t, divided bituminous fuel or mixtures thereof, with or without admixture of other carbonized or partly carbonized materials, such as nely dibelt, the cylindrical surfaceof the rotor within the retort having been previously heated to a temperature suitable for carbonizing the said fuel, such as for example 1300 F., though temperatures of from 800 to 1600" F. may be employed. As the rotor revolves, the coal .is carried by the belt into pressing engagement with the highly heated walls of therotor in a relatively thin, curved layer, and is more or less rapidly heated to .the carbonizing temperatures, the distillation gases evolved being removed through the gas outlet 64. The forward movement of the belt 51 is accomplished entirely by traction with the rotor, andthe degree of belt tension and consequently the degree of pressure exerted upon the thin coal layer while in contact with the rotor surface is controlled by the adjustment of compression of the spring 48. Pressures upon the fuel layer'of from 25 lbs. to 2000 lbs. per s q. ft. may be employed. The speed of rotation of the rotor is so adjusted as to permit the desired degree of carbonizationY of the coal to occur during a single period of contact of the coal with the highly heated rotor, so that the fuel may be either completely or be partially carbonized as desired at the time it is discharged from the carbonizing unit.

The following example is given to illustrate a' preferred modification of my invention involving the carbonization of a bituminous coal. The said coal in finely divided form was fed onto the flex-.. ible wire belt conveyor in a substantially uniform layer 3A" to 78 in thickness, while employing a belt tension equivalent to a pressure upon the coal layer of 186 lbs. per sq. ft. of projected area on the cross section of the rotor, the

temperature of the rotor and the speed thereof being so adjusted that the coal was subjected to a carbonizing temperature at the surface of the rotor of approximately 1100 F. for a period of 30 minutes,-the heat being supplied entirely from the interior of the rotor. The specific volume of the coke produced was approximately 27.6 lbs. per cu. ft., and the crude tar recovered had a tar acid content of 47.8%, a specific gravity at 25 C. of .966, a water content of 20%, and a sulfonation residue value neutral oil) of 37.9%. The gas recovered had aB. t. u. value of 735.

In the event that it is desired to simultaneously carbonize and briquette the fuel, the pocketed link type of conveyor like that shown in Figs. 3 to 6 is employed. The thickness of the fuel layer should preferably be greater than thedepth of the space between the rotor surface and the bot- 'tom of the pockets of the link belt so as to insure a substantial surcharge of fuel into the said pockets. This facilitates the development of the desired degree of compression upon the. material during carbonization and assures the formation of briquettes of the desired structure and density.

conveyor, the temperature of the rotor, and the' thickness of the fuel layer. This facilitates the rapid preheating of the fuel before it nally passes into pressing contact with the highly heated rotor. If desired, means may be provided for applying additional heat to that portion of the rotor supplying the majorportion of the heat for preheating the fuel in this manner. The fuel may be preheated to the desired degree prior to its Aintroduction into the carbonizing apparatus.

In many instances it may be desirable to op? erate the carbonizing unit with a temperature differential from one end of he rotor to the other, of several hundred degrees ahrenheit, in order that the outgoing flue gases willcarry a minimum amount of heat from the system. In such cases,

it is possible in practicing my invention to produce a. uniform high' g'rade char or carbonized product with such uneven heat-distribution by so adjusting the height of the scraper 58 associated with the coal charging -device as tofeed,

sol

' to the temperature of the rotor at such point may be so adjusted that the time of carbonization 'is uniform throughout the width of the fuel layer. As stated above, the time of carbonization is proportional to the square of the layer thickness and is roughly proportional to the fourth power of the absolute temperature of carbonizatior.

While satisfactory carbonization can usually be effected by the use of heat applied through the walls of the rotor to one surface only of the thin layer of material, it may also be desirable under certain conditions to simultaneously heat the said thin layer upon both its upper and lower surfaces by heat supplied from independent sources. When such is 4the case the heating jacket 5 2 'is employed for heating the fuel layer from the belt side thereof. It is then generally desirable to so control the amount of heat supplied by the outer heating jacket that the temperature of the endless belt does not rise substantially above 1000" or 1100 F. However higher temperatures may be employed Where the said belt is made of a suitable heat-resistant alloy such as Hybnickel. As a general rule, where there is a temperature differential between that of the rotor and that of the endless belt of from 400iJ to 500 F., carbonization takes place substantially entirely from the high temperature or rotor side of the coal layer, and the distillation gases leave along the belt side. Under such conditions of operation it is not necessary to heat the belt much above 1000 F., thus adding substantially to the life of the belt. The effective pressures applied to the thin layer of bituminous material being carbonized is substantially less when using the exible woven wire belt than when using the briquetting link-belt described. l For example, pressures of from 150 pounds to 200 pounds per sq. ft. exerted by the fiexible woven wire belt upon the material being carbonized yield a satisfactory'product, whereas the eiective .pressures required when employing a briquetting link belt such as here disclosed usually range from 250 pounds to 500 poundsper sq. ft. and above. Where extremely thin layers of `material are carbonized, as for example layers of 1A, in thickness or less, pressures upon the material of much less than 150 pounds per sq. ft. of rotor projected cross-sectional area may be employed.

The process of carbonizing fuel in thin layers under pressure is applicable to processing either 100% coking coal or mixtures of coking coal and coke, with or without the addition of other carbonaceous materials such as non-coking coal, briquetting agents such as pitch and tar, waterproofing agents and the like.- By its use 100% slack coking coal of high volatile content can be processed to yield a carbonized product having a medium high density of '.'7 and a uniform coke structure. .While, as stated, the process can'be carried out in such manner as to'produce fuelV briquettes from 100% coking coal in a single stage of heating, yet in producing briquettes in a results are generally obtainedv .by employing a mixture of coking coal with a suitable proportion of coke` or of non-coking coal. For example, such scribed, without departing from the spirit of the invention. For example combustible gas may be introduced into the rotor at one end thereof and the products of combustion removed through an axial combustion-gas outlet provided at the opposite end, a suitably insulated air pipe extend- -ing through the rotor axially thereof and having radially-disposed, heat-insulated lateral pipes at spaced intervals, the said pipes extending to points adjacent the inner surface of the rotor and being adapted to introduce secondary air into the rotor at a selected plurality of points adjacent the inner cylindrical surface thereof for burning portions of gas at different points lengthwise of the rotor. Distribution of the hot gases along the-curved inner surface of the rotor may also be assisted by the use of helical bales and the like of refractory material, or any otherwell-known means may be employed for securing a maximum path of travel along the rotor surface for the hot gases flowing through the interior of the rotor.

By the use of my invention as herein disclosed I am able to accomplish the various objects of the inventionk and to provide a continuous process for the low-temperature carbonization of coal and the like in continuous or discontinuous thin layers, which process combines a high rate of throughput with a satisfactory yield of high grade of coke having a uniform cell structure,

' either unformed or in briquetted form, and'which throughput per unit of time is believed to be materially lower than that of the usual carbonization apparatus in use prior to my discovery. The invention is susceptible of modification within the scope of the appended claims.

I claim:

1. Carbonizing apparatus comprising a rotatable hollow drum of heat-resistant material, means for heating the interior of the drum, flexible means, of highl temperature heat resistant material surrounding the drum and adapted to carry material to be carbonized into direct contact with the external surface of the drum, and yielding means associated with the drum and with the said flexible means for moving the twov in unison while pressing them toward 'each other into pressing engagement with the said material and means for adjustingv the pressure thus exerted on the material;

v2. carbonizing apparatus comprising a hollow drum and means for rotating the same, heating means within the drum,` flexible highly heat resistant conveying means encircling thedrum and adapted to have portions thereof and material carried thereby successively brought into direct pressing contact with the surface of the drum, and means associated with the flexible means'for adjusting the degree of pressure of such contact and for maintaining such pressure constant..

3. A carbonizing apparatus comprising a hollowv rotatable tubular member and means for rotating the same, means within the interior of the said tubular member for heating the same, anV endless`conveyor of heat-resistant material encircling; the tubular member and adapted vto engage successive portions of the external curved surface thereof for movement therewith and to carry material to be carbonized into direct contact with the said surface of the tubular member, and adjustable means associated with the tubular member and with the conveyor for continuously pressing the 'said material against the former witha controlled pressure during its engagement therewith.

4. The apparatuses ydefined in claim 3 including additional means at least partially surrounding the said tubular member for indirectly heating 'the surface of the conveyor and the material carried thereby.

5'. The apparatus as defined in claim 3 including separate adjustable means coating with the conveyor for modifying the degree of pressure exerted upon the said material and upon the tubular member by the conveyor and adapted to bend the conveyor inwardly for facilitating discharge of carbonizing material therefrom.

6. The apparatus as defined in claim 3 in which the conveyor .comprises a plurality of pivotally interconnected links, each link having a flat tongue portion at one end and extending longitudinally of the link, a pair of side portions spaced apart transversely of the link at the opposite end thereof, and an intermediate partition extending transversely across the link.-

7. The apparatus as defined in claim 3 including adjustable means adapted to coact with the inner surface of the flexible means for varying the thickness of the layer of material deposited upon the conveyor at spaced-apart points, transversely thereof.

8. Carbonizing apparatus comprising a closed retort, a hollow drum rotatably mounted therein, means for rotating the drum, and meansl for heating the interior thereof, a rotatable idler roll within the retort and having its axis of rotation disposed parallel to that of the said drum, a highly heat-resistant endless belt adapted to encircle both the drum and the idler roll and to engage portions of the surface of each, means coacting with the endless belt for feeding material, to be carbonized onto the inner surface of 'the endless belt, means for moving the idler roll in a path toward and away from the drum and for securing the former at any point in the path of said movement, andmeans co-operating with the belt for effecting the positive discharge of the carbonized material therefrom.

9. An apparatus for 'carbonizing and roasting materials comprising a closed elongated retort having side and end walls, a rotatable, hollow tubular member of high temperature heat-resistant material having its respective ends ex' tending through the said retort side walls, means within the tubular member for heating the same, a heat-resistant endless conveyor adapted to extend around at least a portion o f the external curved surface -of the said tubular memberand adapted to carry material to be carbonized into direct contact with the tubular member, means for urging portions of the endless conveyor into pressing engagement with the tubular member, and means for rotating the said tubular member and for driving the conveyor in unison.

10. A carbonizing'apoaratus comprising a carbonizing chamber, a rotatable member extending into and through the carbonizing vchamber and f means for rotating the same, means within the said rotatable member for heating the walls thereof, a flexible conveyor of high temperature heat-resistant material comprising a plurality of interassociated link members adapted to cooperate wlth the rotatable member to form closed receptacles for the reception of charges of material to be carbonized, and adapted to function to eject from the link members the said charges when the conveyor is flexed, means for moving the conveyor in an endless path that includes an external surface of therotatable member, yielding means for exerting a determinate adjustable and means for feeding material to be carbonizedin a thin layer into the said receptacles.

11. Carbonizing apparatus comprising a hollow drum and means for rotating the same,heat ing means within the drum, a heat-resistant endless conveyor adapted to encircle the drum and engage successive portions of the external surface thereof, the said conveyor comprising a plurality of aligned pivotally interconnected links each having a flat end portion, a forked end ,portion and an intermediate .transverse partition, suc cessive links being so longitudinally aligned and interconnected as to dene an open-topped receptacle between the respective end portions and intermediate ribs thereof, the external surface of thesaid drum being formed with a plurality of annular wedge-shaped ribs, the external surface of thel drum beingl adapted to co-operate with the forked end portions of the longitudinally aligned links to form closures for each of the said receptacles.

12. Carbo'nzing apparatus comprising a closed retort, a drum rotatably mounted therein, means for rotating the drum, means for heating the interior thereof, a rotatable idler member within the retort and having-its axis of rotation disposed parallel to that of 'the drum, a heat-resistant endless conveyor adapted to encircle both the drum and the idler member and to 'engageportions of the surface of each, means coacting with the .endless conveyor for feeding material to be carbonized onto the innersurface of the endless conveyor, adjustable means for moving the idler roll toward and away from the drum and for adjustlng ,the tension in the conveyor and the pressure exerted thereby upon the drum and the interposed material, and a second adjustable means coasting. with the conveyor and adapted to modify the distribution of the pressure upon the drum I effected by the said adjustable means.

13. Carbonizing apparatus comprising a closed retort, a hollow drum rotatably mounted therein, means for rotating the drum, means for heating 4the interior thereof, a rotatable idler member within the retort' and having its axis of rotation disposed parallel to that of the drum, a heat-resistant endless conveyor adapted to encircle both i 'for moving the idler roll toward and away from distribution of the pressure applied upon the 1 and adapted to carry fuel to be carbonized into' contact with the external surface of the drum, means for feeding solid fuel to and for depositing it in a layer upon the inner surface 4of the flexible means, mechanism for rotating the drum, yielding means associated with the drum and with the said flexible .means for* urging the said exible means into pressing engagement with the drum rounding the drum and adapted to carry fuel `to be carbonized into contact with the external surface of the drum, means for feeding solid fuel to and depositing it in a layer upon a surface of the flexible means, which is adapted to contact with the drum, and adjustable mechanism cooperating with the fuel-feeding means for feeding a thicker layer of fuel upon the portion of the exible means adapted to Contact with the porltion of the drum surface adjacent to the said one v'end than'that fed upon the portion contacting with the drum adjacent the other end of the drum.

16. Carbonizing apparatus comprising a closed retort, -a drum rotatably mounted therein, means forheating the interior of the drum, a rotatable idler member within the retort and having its axis of rotation disposed parallel to that of the drum, a heat-resistant endless conveyor adapted to encircle both the drum and the idler member and to engage portions of the surface of each, means for distributing a thin layer of material to be carbonized onto the inner surface of the endless conveyor, means-for moving the said material and the endless conveyor, supporting the same into pressing engagement with the drum and for concurrently rotating the said drum, and adjustable means coacting with the idler roll and adapted for moving the latter toward and away .from the drum and for adjusting the tension in the conveyor'and the pressure exerted thereby upon the drum and the interposed material.

w17;I Apparatus for carbonizing materials cornprising an elongated closed retort having side awalls, -a rotatable tubular heating member having. its ends .extending through the respective side Walls-of the retort, means within the said member for heating `the same, a plurality*v of rigid parts of high temperature heat-resistant mate,

rial pivotally interconnected in serlesand adapted to form a flexible conveyer housed Within the retort and having a series of open receptacles for receiving a pluralityvof shallow fuel charges,

means cooprng, with the said conveyor and adapted toibendfthe conveyor 'inwardly for positivel eiectmentjof the sa'id charges from the re'- vcepftacles, means f orfmoving the said receptacles 'succes'sivelyA vinto contact with a portion of the external surface ofthe tubular member, and adjustable mean-s for continuously exerting a determinate' range fof 'pressures upon the receptacles andlfu'elf charges carried thereby only during Contact thereof with the external surface ofthe saidheating member.

18.*Carbonfilzin'g apparatus' "comprising a carbonizing chamber', a rotatable memberl extending through the carbonizing chamber, means for rotating the said' member, means Within the rotatable member for heating the walls thereof, a flexible conveyer of high temperature heatresistant material mounted within the chamber and comprising a Aplurality of interassociated link members adapted `to cooperate with the rotatable member to form closed receptacles for the reception off-charges of material to be carbonized, means cooperating Withthe link members and adapted to bend the conveyor inwardly for effecting the positive discharge of the carbonized'material therefrom, means for moving the conveyor in an endless path, at one portion of which the conveyor contactswith an external surface of the rotatable member, means for exerting a determinate ,adjustable pressure, upon the link members tof force them into pressing engagement with the said rotatable member, and means for feeding material to be carbonized in a thin layertinto the said receptacles.

19. Carbonizing apparatus comprising a closed retort having therein a hollow drum and means for rotating the same, heating means within the drum, a heat-resistant endless conveyer Within the retort and adapted to encircle the drum andV to engage successive portions of the external surfaces thereof, the said conveyer comprising a series of pivotally interconnected .links each having a flat end portion, a forked end portion andan intermediate transverse partition, successive links being so interconnected and aligned as to denne open-topped receptacles between the partitions of each to contiguous pivotally interconnected links, the external surface of the said drumbeing formed with a plurality of annular ribs ofl wedge-shaped transverse cross section,

the external surface of the drum being adapted to cooperate 'with the forked end portions of the aligned links to form closures for each of the said receptacles.

' HENRY` O. LOEBELL.

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