US1730569A - And irving p - Google Patents

Description

Oct. 8, 1929. E C, RENE ET AL 1,730,569

APPARATUS FOR EXTRACTING VALUES FROM COAL AND LIKE MATERIALS ffarage Oct. 8, 1929. F. c. GREENE ET Al.

APPARATUS FOR EXTRACTING VALUES FROM COAL AND LIKE MATERIALS Filed July 5. 1919 4 SheetS-Sheet 2 4 Sheets-Sheet Filed July 5. 1919 F. C. GREENE ET AL APPARATUS FOR EXTRAGTING VALUES FROM COAL AND LIKE MATERIALS Oct. 8, 1929.

Oct. 8, 1929.

Ec. GREENE ET AL APPARATUS FOR EXTRACTING VALUES FROM COALAND LIKE MATERIALS 4 Sheets-Sheet 4 Filed July 5. 1919 Patented Oct. 8, 1929 UNITED STATES PATENT OFFICE FRANK C. GREENE, OF DENVER, COLORADO, AND IRVING F. LAUCKS, 0F SEATTLE, WASHINGTON, ASSIGNORS T0 OLD BEN COAL CORPORATION, OF CHCAGO, ILLNOIS,

A CORPORATION OF DELAVJARE APPARATUS FOR EXTRACTING VALUES FROM COAL AND LIKE IYIATERTALS Application led July 5, 1919. Serial No. 308,774.

Coal has been defined by one well known authority (V. B. Lewes, in Carbonization of Coal) as being a conglomeration of humus and its degradation 'products with resinic bodies and their derivatives. We have dis covered that at relatively low temperatures and properly controlled pressures these resinic bodies and related hydrocarbon compounds found in such coal and like material can, with proper handling, be removed by distillation and valuable products recovered. The result is the production, or rather recovery, of a larger quantity of aromatic oils, i. e. hydrocarbons of the benzene series, than has heretofore been accomplished or thought possible.

The object of the present invention is the provision of a suitable apparatus for carrying out a distillation process of the character just indicated and more speciically described in our copending application Serial No. 218,452, it being understood that such apparatus is not necessarily limited to any such particular field of use, but may be employed generally in the carbonization of materials such as coal and like carbonaceous ma terial. The apparatus accordingly includes means for handling the raw material, means for retorting the same, means for withdrawing and condensing the volatile matter given off duringithe retorting, as also means for withdrawing the charred residue which, as a result of the treatment to which it is subjected, has been found to constitute a fuel of superior value.

To the accomplishment of the foregoing and related ends, our invention, then, consists of the apparatus or mechanism hereinafter fully described and particularly pointed out in the claims, the annexed drawings and the following description setting forth in detail one approved construction of apparatus, such disclosed construction, however, constituting but one of the various mechanical forms in which the principle of the invention may be used.

In said annexed drawings Fig. 1 is a plan view, more or less diagrammatic. in character, of the layout of a plant equipped for the distillation or retorting of carbonaceous material embodying our present improvements; Fig. 2 is a front elevation of such plant; Fig. 3 is a side elevation of the same as viewed from the left in Fig. l; Fig. 4: 1s a side elevation of the preferred construction of the retort which forms the central feature of such plant; Fig. 5 is partly a top plan view and partly a section at the break in Fig. 4 of several such retorts alined in series and the furnace in which they are mounted; Fig. 6 shows a detail of such furnace; and Figs. 7a and 7b illustrate a vertical section of the retort, or rather of a pair of such retorts looking` in the direction of the alined retorts of Figs. l and 5, the plane of the section being different in the two retort-s respectively, and the second such figure being the lower continuation of the first.

l/Ve do not concern ourselves with the contlicting theories nor the accepted theories relating to the constitution and thermal decomposition of various coals. `We have found that by our apparatus the thermal treatment given the coal results in an increased yield of aromatic compounds compared with the aliphatic compounds over what has been heretofore obtained.

We have found that not only is it necessary to use low temperatures and low pressures in order thus to obtain these `valuable constituents of the coal, but that the limits of temperature wit-hin which these desired hydrocarbons may be vaporized without being decomposed or degraded into others of lesser value, are fairlv narrow. Wie have likewise found that to successfully apply the proper temperature and pressure, the size of the particles of the material being treated, as well as the degree of their dispersion, must be regulated, in order that each particle may obtain a uniform temperature throughout and that particles in the same vicinity in the retort may be uniformly heated to substantially the same degree.

We have also found that if the vapors are allowed to linger in a temperature Zone as high as that required to setthem free, chemical changes will in a measure proceed, and so we accordingly provide for the immediate removal of the vapors away from the region of their formation or heated Zone, in order that they may undergo the least possible degradation.

In the apparatus illustrated in the drawings, vertical retorts of general cylindrical form are utilized in which to heat the coal or like material. The latter is desirably finely ground, the minimum limit of iineness being determined by the conditions attending the handling of a powdered material of this character, both in conveying it to the retort and in passing it through such retort. riChe maximum limit is determined by the speed of the progress of the particle into higher temperature zones, the temperature of such zones, and the resulting thermal conductivity ofthe particle which will vary according to the volatile constituents contained therein. We have in practice found it feasible to work with particles from one-fortieth inch to one-half inch in diameter. The manner in which the material is reduced to the requisite degree of fineness forms no part of the present invention, and need not be described other than to state that suitable crushing mechanism will be provided for this' purpose.

In said drawings, Figs. 1, 2 and 3 illustrate a preferred layout of plant, in which the carbonizing retorts are employed. As there shown, the coal is first fed through a erusher 1, then dried in a rotary drier 2 and afterwards ground to the desired degree of fineness by a mill 3, and carried by means of an air conveyor 4 to the top of the carbonizing tower 5, which consists of a series of paired retorts 6 arranged side by side as shown in Fig. 1, the interior construction of such retorts being shown in Figs. 4, and 7. The retorts are supported within a suitable furnace chamber, or rather chambers, 7. arranged in pairs, there'being a longitudinal series of such pairs of chambers, within which the retorts are disposed., respectively, such chambers being of any desired length, and as many pairs thereof being provided as the size of the operation may make necessary. The retorts are preferably suspended from their upper ends in the furnace chainbers so as to permit free downward variable expansion. The combustion chamber 8 from which the gases for heating the retorts are derived, is conveniently located between the two series of furnace chambers, such heated gases entering the latter at the bott-om through openings 9, as shown in 7b, and escaping at the top through openings 10 into a waste heatflue 11 which, in connection with an exterior duct 11a, conducts the spent gases from the chambers to the drier Q, so as utilize the waste heat as fully as possible.

A lighting hole 12 leads from the exterior of the one furnace chamber to said combustion chamber for igniting the combustible mixture of air and gas supplied to the burner 13 therein from air and gas mains 14 and 15 respectively. The latter are simultaneously controlled by means of valves 16 and 17 operated by means of suitable levers and a connecting rod 18, likewise extending without the wall of the furnace chamber. A hole 19 is also provided in the wall of each chamber near the bottom of the latter for the insertion of a pyrometer (not shown) in order to determine the temperature within such chamber.

Each retort 6, proper, consists of a vertically disposed tube, preferably of iron, which extends the length of the furnace, such tube being provided with external ribs 2O disposed in a helical fashion about the same, that cause the combustion gases, as they pass upwardly through the furnace chamber, at the same time to circulate about the retort, and so insure the thorough and, uniform heating of all portions of the same, and large absorption of heat.

Within each such tubular retort is rotatably mounted a second tube 21, the upper end of which projects beyond the upper end, not only of the retort proper, but of a head 22 that surmounts the latter. Inner tube 21 is provided externally with a spiral rib or flange 23, that extends from its lower end to a point adjacent the upper end of the retort, and is of a width to substantially span the annular space left between the tube and retort. The relative diameters of the retort tube 6 and the rotary tube 21 are such that the annular space between them is relatively narrow, the reason for this appearing more fully hereinafter. Said inner tube is also provided, between the flights of such spiral rib, with a series of perforations 24, that permit and afford free communication for vapors to quickly escape from the annular spa-ce between the retort walls and such tube, to the interior of the latter. The upper end of each such inner tube is closed by a vacuum seal consisting of a counter-weighted valve 25, that is held to its seat by the vacuum within the tube produced, as will be presently described, but is adapted to open automatically upon the breaking of such vacuum. Driving means for rotating each tube 21 are likewise connected with the upper ends thereof, such means consisting of a ratchet wheel 26 operated by a pawl 27 on an oscillatory arm 28 the free end of which engages a camk 9.9 on the main drive shaft 30 of the apparatus. To reduce power required for rotating these tubes, a suitable ball-bearing 31 is employed under the upper bearing-flange 32 in the head 22.

The upper portion of the head 22, that surmounts each retort is sealed off 'by means of a suitable flange `from the lower portion thereof, which latter freely communicate with the retort, that is, with the annular space between the inner tube 21 and the relll) tort walls; while above the partition, provided by such flange, other perforations 36 are formed in said inner tube, by means of which its interior is connected through a duct 37 with a vapor main 38, that is placed under suction by means presently to be described,.and the desired degree of vacuum thus provided within the tube. A valve 39 isprovided in each duct 37 for closing the saine simultaneously ywith the opening of a discharge gate 4() at the bottom of the char chamber 41, and vice versa, as will also be presently described.

Connected with each head 22, below the partition therein just referred to, is a duct that is adapted to receive the finely ground coal, or like material, from a conveyor trough 46 and supply the same to the upper end of the retort. The rate of feed is controlled by means of a screw 47 located intermediate between the ends of such duct, this screw being connected to be operated from the drive shaft 30 by means of a chain 48 and suitable variable speed gearing 49, which need not be described in detail. A. valve 50 for closing the duct 45 is also provided, such valve being interconnected with the valve 89 in the corresponding vapor duct by a link 51.

The lower end of each retort communicates with, and discharges directly into, the char chamber 41 above referred to, that is located directly therebeneath. The lower end of such char chamber in turn is adapted to be sealed by means of thel discharge gate 40, likewise referred to above, that is pivotally attached at one side of the chamber and normally held closed by means of a swinging yoke adapted to engage therewith through the medium of a roller 56 and tightly close the same as it is swung from the position indicated in dotted lines, to that indicated in full lines, in Fig. 7b. In order always to insure a tight closure and to prevent the charred material from getting caught between the gate and the lower end of the chamber 41, such end is formed with a downwardly directed encircling groove 57 into which the beveled edge 58 of the gates is adapted to fit7 all as clearly shown in the same figure. Y

As previously indicated, the operating means for this discharge gate, specifically the yoke 55 just described, is interconnected with the valve 39 in the corresponding vapor duct 37 at vthe upper end of the retort, the rod 59, that serves for this purpose, extending well above the retort and serving, when raised, not only simiultaneously to close the discharge gate in question and to automatically open the valve in the vapor duct, but also, through the link 51, to open the valve in the feed duct, and, through the medium of a projection 60 on its upper end, to automatically lift the weighted arm of the valve 25 that closes,

' or seals, the upper end of the-.inner tube of the retort. The operative connections between rod 59 and the yoke 55 include a transverse bar 61 secured to the lower end of said rod, the respective ends of which are held in grooves or slots 62 formed in a comple mentary pair of segmental plates 63 carried by said yoke, one on each side. These slots, it will be observed, comprise two communicating arcuate portions that have the axis 64 of the yoke for their common center, but the uppermost such portion, in the position of parts shown in Fig. 7b, is disposed at a slightly greater radial distance from such axis than the other. There is also an offset or ledge 65 formed on the side of the charchamber 41 adjacent the lower end of said rod 59, adpated to receive and support a roller 66 mounted on the aforesaid bar 61, when the rod is in its upper or raised position.

lVhen the yoke 55 is swung to the left in the figure of refernce, such movement does not initially have any effect on the rod, the portion of the respective slots 62, then in engagement with bar 61, retaining such bar in position where said roller 66 rests on ledge 65. Further swinging movement of the yoke, however, serves simultaneously to release the gate 40 and to shift said roller 66 olf the ledge in question, so that the rod 59 is free to drop and thereby actuate the several valves connected with its upper end. A full range of movement of the rod in this direction is insured by the engagement of the other portion of slots 62 with the bar. Upon reverse swinging movement of the yoke, as soon as the midpoints in slots 62 are brought into Contact with said bar, the latter is lifted, thereby elevating the bar, until the roller 66, which rides the while on the lateral face of offset 65, reaches the upper face of the latter. Then the lower portion of slots 62 pull said bar inwardly and cause the same to seat as before on top of the offset or ledge. A spring buffer 67 is mounted alongside chamber 41 in position to engage a stop 68 on rod 59 in the lowered position of the latter, as will be readily understood, while a turnbuckle 69 in said rod permits of its adjustment as to length.

ln addition to provision being made for the withdrawal of vapors from the interior of the inner tubes of the several retorts, a second vapor main 7 O is disposed alongside the lower ends of the series of retorts and is connected with the upper portions of the corresponding char-chambers 41 through suitable ducts 71 that are controlled by valves 72 operatively connect-ed with the rods 59, just as are the valves in the upper ducts. lVe also provide in this connection a piston or stopper` 75, that is adjustably litted within the lower end of each inner tube, being of eXpansible c0nstrucrod caused to frictionally seat itself in such selected location. The location of this piston, or stopper, will obviously determine the point at which, in the descent of the material through the retort,` the vapors given off therefrom are conducted upwardly and collected in vapor main 38, and the point at which the vapors thus given off are conducted downwardly and collected in the lower vapor main.

rlhe charred or carbonized residue, upon being` discharged from chambers 41, is received and collected in a receptacle of adequate size, the side walls of which converge towards a troughdike depression 8O in which an endless belt 81 or other conveyor operates to transfer this material to any desired point. As shown in Fig. 1, this material, after being conveyed to the further, i. e. right-hand, end of the series of retorts or retort tower, is carried by another conveyor 82 to a storage bin 83.

The vapor mains 38 and 70, with which the interiors of the several retorts and the charchambers are respectively connected as hereinbefore described, lead to vacuum pumps 84 in the condensing and distilling plant 85 (Figs. 1 and 2), the connections 86 for said main 38 only appearing. Here, after condensation, the products are received in suitable tanks or containers, thereafter to be further treated to separate the various constituents with such degree of refinement as may be desired in the particular case.

By locating the crushing and drying plant, the condensing and redistilling plant, and the storage bin for the carbonized residue, all on the same side of the retort tower 5, a very compact arrangement is rendered possible, facilitating the handling of the material in its various stages andenabling a single track 87 to serve both the receiving and discharge ends of the plant. Moreover, as indicated in dotted lines in Fig. 1, by carrying projections of ducts i and 8G as well as of the conveyor 82, a plurality of series of retorts or retort towers 5 can be connected up in the same fashion as the one shown in full outline with the several parts of the plant.

VHaving regard to the illustrative apparatus just described, the manner of operation, exemplifying our improved method or process for extracting values from coal and like material, may now be briefly set forth. The suitably crushed, and preferably dried, material is received in the upper end of the retort, or rather into the upper end of the annular space between the rotatable inner tube in such retort and the inner wall of the latter, from the conveyor through the feed duct 45. The feed screw 47 in such duct serves to regulate the rate of feed.

The rate of feed is regulated so as to supply the material in a stream of suitably adjusted quantity on the spiral flange 28 carried by the rotating inner tube. The material, in other words, is passed through the retort in the form of a relatively thin vertical (in this case) layer resting on this flange, the particles not only being sufficient-ly small, but so dispersed as to be all practically uniformly heated throughout. Owing to the heated contact area of the retort wall presenting sufficient frictional resistanceto the thin stream of coa-l, or like material, to cause such stream to rotate in its passage along the heated surface, a churning action results which tends to continually present fresh surfaces, or to prevent the continuance of the same surfaces, to the heated contact area. This action is im.-l portant as tending to expedite and facilitate the evolution of vapors and their ready withdrawal, constituting an effect similar to dispersion. The annular space containing the material being relatively narrow, as hereinabove stated, contributes not to the frictional resistance of the material adjacent the retort wall, but to the amount of rotation or circulation produced in the stream of coal by reason of such frictional resistance. It is clear that any particle of material resting on the flight of the rotor tends to advance downward through the retort only by the action of gravity, and that the frictional resistance between the particle and the rotor flight tends to carry the particle in a circular path about the axis of the retort. Then any particle contacts the stationary outer wall, the friction therewith holds it back in its circular orbit and advances it downwardly through the retort. So with a large number of small particles on the flight, those adjacent the retort wall advance more rapidly and their place is taken by particles which were previously not in contact with the outer wall. Thus the churning action is produced by the resulting movement of particles into and out of contact with the wall. And it is important in taking advantage of this churning action, that the width of the annular space be small to bring all the particles more frequently into contact with the heated Wall in the course of the churning, thereby distributing the heat by convection and conductance. The mode of supplying the heated gases to the furnace chamber, taken in conjunction with the arrangement of ribs 20 on the retort insures an equable heating effect and absorption of heat in all horizontal.

"planes, although the heating gases `are of course hottest in the lower portion of the furnace chamber and gradually cool off-as they ascend vertically, due to the absorption of heat by the material as it passes downwardly through the retort. A higher temperature may be used in the lower section of the retortto drive off' all volatile matters from the material being treated, and thus approximate known coking processes.

Additional burners may be applied to the retort 1 at various'points along its length to provide heat to a degree commensurate with the absolute pressure, fineness and composition of the coal or like material, and speed of operation employed, and with the degree of expansion of evolved vapors. A relationship exists between these, and possibly other elements of operation, which elements when properly adjusted, or synchronized, constitute the process resulting in maximum roduction of evolved condensible vapors o the valuable aromatic series.

External heating temperatures may thus be varied, as may pressures, speed, ineness. Such temperatures we have found may vary from say 800o F ahr. to 12000 Fahr. although these limits are not fixed. Apparently the limiting element of this opera'- tion is the reduction of pressure to a perfect vacuum, which, while practically unobtainable, is the desideratum. Provision is made for tightly-sealing the retort at both ends, and, by means of suitable suction apparatus connected with the two vapor mains, we reduce the pressure within the retort to the lowest possible degree, any increase in the pressure towards atmospheric resulting in a corresponding decrease in the amount of aromatic oils in the products obtained.

The suction thus employed in order to reduce the pressure within the retort is simultaneously effective to with-draw the vapors, as fast as they are formed, away from the heated zone; that is, they are sucked through the apertures in the inner vapor tube and thence to suitable collecting and condensing apparatus, such vapor tube being found to have a considerably lower temperature under these conditions, by at least several hundred degrees, than the external heating temperature.

lVherc it is desired to drive off all the volatile constituents possible by applying to the lower portion of the retort a higher range of temperature than that indicated above, the use of a piston or stopper within the vapor tube is desirable, since in this way it is rendered possible to segregate the so-called lean gases resulting from this stage in the process, from the vapors, rich in aromatic hydrocarbons, which are evolved in the initial or main stage of the process. In other words, by the means in question we are enabled to ef'- fect a fractional distillation of the volatile constituents in the original material. Such fractionating may be carried further if desired, for we have found that, by proper manipulation of the temperatures within the retort and vapor tube, the vapors given off may be made to consist more largely of either lowboiling or high-boiling compounds as desired.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

We therefore particularly point out and distinctly claim as our invention 1. ln apparatus of the character described,-

the combination with a furnace; of a vertically disposedcylindrical retort located within such furnace; a perforated tubular member rotatable within said retort and leaving a relatively narrow annular space, the upper end of said member projecting above such retort; means adapted to supply material to be treated to the upper end of such space, said member being provided with spiral ribs adapted to regulate the passage of such material through such space; suction connections for withdrawing vapors from the upper and lower ends of said member, respectively; a valve adapted to close the upper end of said member under the suction thus maintained therein; and means adapted to simultaneously control said suction connections and said valve.

2. ln apparatus of the character described, the combination with a furnace; of a vertically disposed cylindrical retort located within such furnace; a perforated tubular member rotatable within said retort and leaving a relatively narrow annular space, the upper end of said member projecting above such retort; a char-chamber forming a continuation of the lower end of said retort; a hollow head surmounting the upper end of said retort and surrounding said member, said head having a transverse partition; means adapted to supply material to be treated to such head below such partition; and suction lines connected with said head above the partition therlein and with said char-chamber, respective y.

3. In apparatus of the character described, the combination with a furnace; of a vertically disposed cylindrical retort located within such furnace; a perforated tubular member rotatable within said retort and lea-ving a relatively narrow annular space, the upper end of said member projecting above such retort; a char-chamber forming a continuation of the lower end of said retort; a hollow head surmounting the upper end of said retort and surrounding said member, said head having a transverse partition; means adapted to supply material to be treated to such head below such partition; a transverse partition at an intermediate point within said member; and suction lines connected with said head above the partition therein and with said char-chamber, respectively.

4. ln apparatus of the character described, the combination with a furnace; of a vertically disposed cylindrical retort located within such furnace; a perforated tubular member rotatable within said retort and leavinga relatively narrow annular space, the upper fil end of said member projecting above such retort; a char-chamber forming a continuation of the lower end of said retort; a hollow head surmounting the upper end of Said retort and surrounding said member, said head having a transverse partition; means adapted to supply material to be treated to such head below such partition; a transverse partition at an intermediate point Within said member;

' suction lines connected With said head above the partition therein and With said charehamber, respectively; valves in said Suctionlines; another valve adapted to close the upper end of said member under the suction thus maintained therein; and means adapted to simultaneously Control said valves.

Signed by me7 this 28 day of June, 1919. FRANK C. GREENE. Signed by me, this 24 day of June, 1919. IRVING F. LAUCKS.

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