US1358664A - Process for distilling carbonaceous material - Google Patents

Description

Patented Nov. 9, 192()g G. WQWALLAC'E.

PROCESS FOHDISTILLING CARBONACEOUS MATERIAL.

APPLICATIN FILED JUNE 16, 1919.

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UNITED srArEs PATENT OFFICE.

GEORGE W. WALLACE, 0F EAST ST. LOUIS, ILLINOIS.

PROCESS FOR DISTILL-ING CARBONACEOUS MATERIAL.

Application led June 16,

To all rr11/tom t lmuy concern.'

Be it known that I, GEORGE W. l/VALLAoE, a citizen of the United States, residing at East St. Louis, Illinois, have invented a certain new and useful Improvement in Processes for Distilling Carbonaceous Materials, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the carbonization or distillation ofsolid carbonaceous materials, such, for example, as coal, lignltes and other fusible bituminous substances.

I 1When coal is carbonized or distilled in a closed chamber or retort provided with a take-off duct arranged at the coolest portion of the charge and constituting the sole outlet for the gases, vapors and liquids evolved in the distilling operation, the coal in the retort becomes coked progressively, as the heat penetrates inwardly through same, the heat causing the coal to fuse into a molten mass and then solidify gradually into permanent coke. As the distilling operation proceeds, the coking zone, represented by the fused or molten mass, moves inwardly progressively toward the take-oft' duct or collection chamber at the coolest portion of the charge, thus leavinor a body of coke in the zone lying outside of the coking Zone. At the beginning of the operation the coal in proximity to the wall of the retort, to which the heat is applied, tirst softens and starts to give. off gases high in methane and oils that are light in gravity and very volatile, most of the moisture in the 'coal being driven oil at this period of the operation. As the temperature is elevated the coal begins to melt and turn into a putty-like mass, and when a temperature of approximately G5()C F. to

'T500 F. is reached, the coal is a boiling, bubbling mass. Thereafter, this'boihng, bubbling mass gradually solidihes or changes into permanent coke. At the completion of the coking stage or at the first stage of the conversion into permanent coke, the mass is dense, impervious and in the form of a relatively thin layer or wall of solidifying material that extends vertically through the retort, and which acts as a barrier between the boiling, bubbling mass in the coking Zone and the permanent coke or material lying on the other side of said barrier which has passed through the coking Specification of Letters Patent.

1919. Serial N0. 304,417.

stage. In numerous tests that I have made with various kinds of coal, I have found that the vertical barrier just referred to is usually less than one-eighth of an inch in thickness and that it conforms approximately to the shape of the heated4 wall of the retort and extends vertically throughout the entire height of the body of material in the retort. ence, said barrier effectively cuts ott the escape into the take-off duct of any gases that continue to evolve from the material outside of the coking Zone which has passed through the coking stage. I have also discovered that any disturbance of the thin barrier or layer of solidifying coke adjacent the molten mass in the coking zone, such, for example, as the passage through said barrier of gases that are evolved on either side of the barrier, has a permanent effect on thestructure of the coke and produces coke that is fragile and in the form of small pieces. This is due to the fact that the passage of gases through said solidifying mass forms cracks in same which develop into wide. fissures when the material constituting the barrier sets or shrinks during the last stage of the conversion into permanent coke.

If the volatile matter that is continually escaping from the boiling, bubbling mass in the coking zone, consisting of most of the oily hydrocarbons and probably 50% of the gases that are evolved from the coal', is allowed to follow the path of least resistance in escaping from the distilling chamber, there is a tendency for said gases to break through the barrier adjacent the bubbling mass of coal and flow outwardly through same, instead of in the opposite direction through the material lying between the takeoff duct and the boiling, bubbling mass in the coking zone, due to the fact that said material is more impervious than said barrier and is composed of partially melted coal of putty-like consistency and green coal that is impregnated with densed viscid products that have become mixed with the green coal. The passage of any gases outwardly through said barrier not only forms fissures in the barrier, thus producing a poor quality of coke, as previously described, but the passage of gases outwardly through said barrier also causes the volatile matter evolved from the coal to come in contact with the incandescent coke pitchy oils and conlying outside of the coking zone, and thus undergo secondary decomposition, thereby destroying much of the oil and gas and forming free carbon and lamp black along with gaseous hydrogen, which is the poorest of allartii'cial gases from a heat unit standpoint.

rl`hc passage ot the gases and vapors outwardly through the barrier adjacent the boiling, bubbling mass in the colring Zone can be prevented by creating a suction in the take-oit duct of sufficient intensity to overcome the resistance offered by the puttylilre mass ot' partially melted coal and the mass of pitch impregnated coal lying between the take-off duct and the colring zone, but even when a suction is employed to draw the gases, vapors and liquids into the takeoff duct, there is still considerable danger of the thin barrier ot soliditying material in the colring zone being disrupted, due to the passage inwardly through said barrier of that continue to evolve from .the material lying outside of the coking zone. Furthermore, there is a tendency for the gases that continue to evolve from the niaterial that has passed through the Lcolring Stage to build up pressure in the retort and crack the retort, it it be made of clay or silica, thus permitting fuel gases to come in contact with the gases and liquids evolved from the coal and ruin said evolved gases and liquids. f

Accordingly, in distilling coal in a closed retort or distilling chamber provided with a takeoff duct or collection chamber that constitutes the sole outlet for the evolved gases, liquids and vapors, it is essential to prevent the solidit'ying material in the colring zone troni being disrupted by the passage through same ot gases that are evolved either trom the material in the colring Zone, or from the material that has passed through the colring stage. Furthermore, when al suction or partial vacuum is used in the takes ott duct to withdraw the gases, vaporsl and liquids evolved from the material in thel coking zone, it is necessary to prevent said suction from being exerted on the outside ot the barrier vadjacent the molten mass in the coking Zone, namely, the side nearest to the heated wall ot' the retort, as any suction exerted on the outer side ot said barrier tends to cause the gases evolving in the colting zone to torce their way outwardly through said barrier, due to the greater resistance that the material lying between the take-oit duct and the molten mass offers to thc passage ot such gases.

M v invention has tor its main object to provide a practicable process tor distilling or carbonizing t'usiblc bituminous substances that insures the production ot a good grade ot coke, even from inferior qualities of coking coals, and which also insures the recovery ot' a high percentage of the oils and volatile constituents in bituminous substances.

Another object is to provide a rapid process tor distilling or carbonizing fusible bituminous substances that can be accurately controlled and which can be practised in a retort or distilling chamber formed ot' re- Jractory material such as clay or silica.

To this end l have devised a process tor distilling, carbonizing or vaporizing solid carbonaceous material which is characterized by subjecting a continuous body of material ot the character mentioned to such treatment in a retort or closed distilling chamber that the gases', vapors and liquids which are evolved trom the material passing through the coking stage will travel through the coolest portion of the material in the distilling chamber in escaping therefrom and providing unobstructed passageways in the material in the distilling chamber through-which gases can escape from the zone lying outside of the coking Zone Without .disrupting the solidifying material that is changing into permanent coke. The gases and liquids that are evolved from the material passing through the colring stage are preferably drawn into a take-oit duct or collection chamber located at the coolest portion ot the charge by means of a slight suction or vacuum which also assists in collapsing the bubbles in the molten mass in 'the coking zone, as said molten mass gradually changes into a solid state, and the passage-V ways that are provided for the escape of the gases which continue to evolve from the material that has passed through the coking stage are so formed that there is no liability of their becoming obstructed and no liability ot the suction being everted on the outer side ot the thin barrier of soliditying material adjacent the molten mass in the coking Zone, in a direction tending to cause the gases and vapors evolving from said molten mass to pass outwardly through said barrier.

My present process is similar to thek process described in my prior-U. S. Patent No. 1,283,001, dated October 29, 1918, in that it provides Jfor distilling solid carbonaceous material in a closed distilling chamber in such al manner that the evolved gases, vapors and liquids travel through the coolest portion of the material in said chamber into a take-oft duct, and thence immediately escape through said take-off duct before secondary decomposition can occur, preterably downwardly to an eduction pipe communicating with the lower end of said take ott duct, but it diiters from my said prior process in that it contemplates providing means torlreeping thevsoliditying material in the coking zone intact and permitting the escape into the taire-oit duct ot any gases that continue to evolve trom the material which has passed through the coking stage.

The apparatus that I have herein illustrated for practising my present` process forms the subject-matter of my divisional application Serial No. 390,187, tiled June 19, 1920, and consists of a closed distilling chamber or retort, a take-oft duct' or collection chamber arranged preferably inside of said distilling chamber at the center of same and of the same general contour as the side wall of the distilling chamber, the lower end' of said take-ottl duct communicating with a suction-producing device, and members projecting radially from said take-oft duct into the material in the distilling chamber and constructed so that they form unobstructed passageways extending through the coking zone, through which gases can travel into the take-ofi duct `from the zone outside ot' the coking zone. Various other forms ot apparatus can be used, however, for practising my process, and therefore I do not wish it to be understood that my process is limited to use with an apparatus ot' the particular construction herein shown.

'Figure l of the drawings is a vertical scctional View of one form of apparatus that can be used in practising my present process.

Fig. 2 is an enlarged detail sectional view, illustrating the construction ot one of the radially-projecting devices on the take-ottduct that forms a passageway extending outwardly from the take-oli duct through the coking zone; and

Fig. 3 1s a cross-sectional view, taken on the line 3-53 of Fig. 2.

The apparatus shown in Fig'. l comprises a closed distilling` chamber or retort A that is adapted to contain a continuous body ot solid carbonaceous material, means tor eX- ternally heating said chamber, such, tor example, as a combustion .chamber B to which products of combustion are supplied and arranged in proximity to the side wall of the chamber A, a take-oit duct or collection chamber C arranged at the center ot the distilling chamber A and having its lower end communicating with an eduction pipe D which is connected with a suctionproducing device (not shown) and a plurality ot' devices l projecting radially Jfrom the take-oli' duct into the body of material in the chamber A and so constructed that 'they form unobstructed passageways l that extend from the take-off duct C through the coking zone and into the material lying outside ot the coking Zone that has passed through the colring stage. ril`he particular construction and arrangement ot the devices lil is immaterial, so long as they provide unobstructed passageways that extend through the colring Zone and establish communication between the taire-oil duct C and the portion of the distilling chamber lying outside of or beyond the coking zone without liability of causing the suction in the take-orf duct being exerted on the outer side of the barrier ot soliditying material that surrounds the molten mass in the colring zone. I prefer, however, to form the devices E Jfrom short tubular members screwed into the take-off duct C or connected to same in anyv other suitable manner andprovided with openings la through which the gases and vapors can enter the passageways l.

ln the apparatus herein shown the members E are closed at their outer ends and are provided on their undersides With slots la that extend longitudinally of said members, and thus permit the gases to enter the passageways 1 at any point throughout the length of said passageways.

lVhen heat is applied to the Walls ot the distilling chamber A the material in said chamber will become coked progressively, as the heat penetrates inwardly through said material. As the coal begins to heat it softens and starts to give olf gases and oils. The oils are light in gravity and very volatile, and the gases are high in methane, most of the moisture in the coal being driven ott at this period in the carbonization. The coal begins to melt as the temperature is elevated, and after it has been partially melted, it is of putty-like consistency and almost impervious to the passage of gases and vapors, due to the fact that little ot it has been decomposed into the more solid'products formed later in the distilling' operation. The pitchy oils which result from the partialv decomposition of the coal completely till the voids between the pieces of coal, and being very viscid, offer great resistance to the passage ot the volatile products which have resulted from the decomposition of the coal lying closer to the source of heat that has undergone more nearly complete decomposition. The melted, pitch saturated coal gives oil" considerable gases, but due to the fact that condensation oit the heavier fractions from the more completely carbonized zone occur, the evolution is somewhat retarded and only the hydrocarbons of a lighter gravity and the permanent gases escape from the decomposing coal in this zone. Located immediately adjacent to this zone, but toward the side. wall of the retort to which the Vheat is applied, the coal is a boiling, bubbling mass. The temperature of this mass is approximately 650 F. to 750o F., these temperatures indicating the beginning'and ending of the reaction. It is from this boiling, bubbling mass that most ot' the volatile matter escapes,'and it is at this point that almost all of the oily hydrocarbons are formed and probably :30C- of the gases evolved. immediately outside tinues to give oil" its volatile matter, there.

after grat-lually setting harder and harder into permanentcoke. As breviously stated,

it is essential that this thin layer of solidifying material, constituting a barrier' bctween the molten mass in the coking zone and the permanent coke lying outside ot the coking zone` be kept intact, tor any disturbance of same at the period when it is setting or bccomin, ;l hard is bound to make the resultant coke fragile, filled with large bubbles. and in the 'form of small pieces, ln Fig. oi the drawings'l have used the reference character X to designate the boiling, bubbling mass in the coking Zone that is passing through the coking stage, the relierence character Y to designate the thin vertical barrier of' solidifying coke that surrounds the molten mass in the coking Zone and separates it from the material Z lying outside oi the coking zone which has passed through the coking stage, and the reference character lVto designate thel material lying between the center take-off duct and the boiling, bubbling mass in the coking zone. ln view oli' the fact that the vertical barrier Y is very thin, usually less than one-eighth ot an inch in thickness, it has been herein represented by a solid line.

The devices E previously referred to that project radially from the center take-oil duct, pass through the barrier Y that separates the molten mass X in the coking zone from the material Z that, has passed through the coking'stage. Consequently, any gases that continue to evolve from the material Z lying outside of the coking zone will travel inwardly through the passageways l in the devices E into the take-off duct C. thereby eliminating the possibility of the barrier Y being disrupted at the. critical stage in the coking operation by'the passage inwardly through same of gases that continue to evolve from the material that has passed through the cokiug stage, and also eliminating the possibility ot' pressure building up in the retort outside of the coking zone suliiciently to crack the retort.

The take-olf duct can either be provided with numerous orifices 2 through which the gases, vapors and liquids evolved `from the material in the coking zonel and from the material lying within the coking zone are admitted to said take-oli' duct, or the radially-projecting devices E on the take-oill duct can constitute the sole inlet into the take-oli duct for the evolved gases, vapors and liquids.

During the distilling operation the gases, vapors and liquids that evolve from the material passing through the coking stage are drawn inwardly into the take-oli' duct C by the suction or vacuum therein, said gases, vapors and liquids entering the take-off duct either through the perforations 2 therein or through the passageways 1 in the radiallyprojecting devices E. The gases, vapors and liquids that enter the take-off duct C travel downwardly through same to the eduction pipe D through which they are immediately conveyed away from the apparatus. ln view oi the tact that the take-oil duct C is arranged at the center of the distilling chamber at the coolest part ot' the body of material in said chamber, the gases, vapors, and liquids that are evolved from the material which is passing through the coking stage will travel through the coolest portion ot' the material in the chamber A in' escaping from said chamber, thus causing a reduction in the temperature of the gases, vapors and liquids below the initial temperature of formation, and consequently preventing any further breaking down o the hydrocarbon molecules. As the liquids are immediately conducted out of the apparatus through a take-oil" duct which is so :formed that no liquids can collect and remain therein, there is no possibility of the liquids condensing, revaporizing or becoming cracked or mixed with the material in the distilling chamber that` surrounds the take-oli duct C.

The frasesq that continue to evolve from the material outside of the coking zone, also pass into the take-oft' duct through the passageways l extending throughthe coking zonet Consequently, there is no possibility of pressure building up in the retort outside ot the coking zone X sulliciently to crack the retort or disrupt the thin barrier Y of solidifyingzmaterial that separates the molten mass in the coking zone from the permanent coke. A relatively slight suction Y is employed to withdraw the. gases, vapors and liquids from the retort,in fact, only a suction of sufficient intensity to assist in collapsing the bubbles in the boiling mass in the coking zone and to overcome the resistance offered by the putty-like mass 01' partially melted coal and the mass of pitch saturated coal lying between the take-olf duct and the coking zone. The suction should be great enough,-however, to causethe escape into the passageways l of the gases that continue to evolve from the material lying outside of the coking zone that has passed through the coking stage, butV not strong. enough to cause the gases evolving in the coking zone to force their way outwardly through the barrier Y. This desirable result is accomplished in my improved process and apparatus by reason of the fact that the gases which continue to evolve from the material lying outside oi the coking zone are conducted into the center take-off duct through devices E which are of such a character that the fused material in the coking zone will seal itself around said devices during the coking operation, -and which are so constructed that the permanent coke in the zone Z tends to obstruct the inlet slots la on the underside of' the devices E, thereby creating a differential pressure on opposite sides of' the barrier Y. In other words, in my process the gases that tend to disrupt the solidifyinginaterial in the colring zone are conducted out of the retort through unobstructed passageways penetrating through the colringV zone, but entirely surrounded by fused coal which seals and cuts of'f any communication be tween the green coal and the permanent coke except through said passageways, thus preventing the suction or vacuum employed to withdraw the gases from actingon both sides of the barrier Y of solidifying material in the coking zone.

From the foregoing it will be seen that the process above described insures the production of a good grade of coke that is firm and' inthe form of large pieces; it eliminates the possibility of pressure building up in the' retort outside of the coking zone sufficiently to crack the retort, if' it be made of clay or silica, and it insures the recovery of a large percentage of the volatile constituents in the carbonaceous material being treated by the process.

In the apparatus herein shown the takeoff duct C is provided at its lower end with a laterally-projecting flange 3 which supports or sustains the material in the distilling chamber A, and said take-off duct is arranged in the distillingchamber in such a manner that it is adapted to be drawn upwardly through said chamber to discharge the contents of the distilling chamber, the upper end of the distilling chamber being closed by a removable cover 4. In such an apparatus, namely, one in which the take-off duct sustains the charge, the radially-projecting devices E on the takeoff duct have a dual function, namely, they permit the escape into the take-ofi' duct of any gases that evolve from the material lying outside of the coking zone and they tend to hold the coked residue of the distilling operation on the take-oflduct while said take-olf duct is being withdrawn from the retort and conveyed away to the point where the coke is to be ouenched or stored.

Having thus described my invention. what.

I claim as new and desire to secure by Letters Patent is:

1. A process for distilling, carbonizing or vaporizing solid carbonaceous material, characterized by subjecting Aa continuous body of material of the character mentioned to 'heatina closed chamber, and Withdrawing the evolved'Qases,..vapors andliquids and maintaining the material in the coking zone in uninterrupted condition. 2. A process for distilling, carbonizing or vaporizing solid carbonaceous material, characterized by subjecting a' continuous body of material of the character mentioned to heat in a closed chamber in such a. manner that the material in said chamber becomes coked progressively, withdrawing the evolved gases, -vapors and liquids by. reduced pressure through thecoolest portion of the material and conducting said` gases, vapors and liquidsout lof the apparatus before secondary decomposition' can occur and causing the gases that continue to evolve vfrom thel material'that has passed through .the coking stage to pass through the layer ofsolidifying material in the coking zone and escape from said chamber-whilemaintaining the material vin the coking zone. in uninterrupted condition.

3.V A process for distilling, carbonizing or vaporizing solid carbonaceous material,

characterized bv subjecting material of the character mentioned toy heat in al closed f chamber so as to liberate and drive off the Volatile constituents,withdrawing thev rier of solidifying material in the coking.

zone so as to permit the escape of any gases which continue to evolve from the-material that has passed through the colring stage.

4. A process for distilling, carbonizing or vaporizing solid carbonaceous material, characterized by applying heat externally to a closed chamber containing a continuous body of material of the character mentioned. subjecting the material in the coking zone to the action of aA suction of sufficient intensity to assist in the collapse ofthe bubbles in the molten mass in said zone and also withdraw the evolved gases, vapors and liquids, and causingrthejgases that continue to evolve from the material that has passed through the coking stage to escape from said chamber While maintaining the material in the colring zone in uninterrupted condition. p 5. A processfor distilling, carbonizing or vaporizing solid carbonaceous material, characterized by subjecting material of the character mentioned to heat in a retort or distilling chamber provided with a center take-off duct or collection chamber, providing and maintaining unobstructed passageways in said material that branch radially from said takeoff duct. and creating a suction in said take-olf duct of sufficient intensity to Withdraw the evolved gases, vapors and iiquids without nabnay of disrupting' the barrier of solidifying material that separates the molten-mass in the coking zone from passed through the.

' the escape of gases that continue to evolve the material which has cokinlgstage.

6. process for distilling', carbonizin'g or vaporiziny solidicarbonaceous materialffc'iharacterized y applying heat externally toa chamber containing solid carbonaceous material, causing the gases, vapors and liquids that are evolved from the material passing through the coking stage to travel through the coolest portion of the material in said chamber into an olf-take passageway and providing unobstructed passageways in the body of material in said chamber, that branch radially from said off-take passageway at a plurality of levels and through which 'gases can travel into said oif-take passageway from the zone lying outside of the coking zone.

7, A process for distilling, earbonizing or vaporizing solid carbonaceous material, characterized by vapplying heat externally to a chamber containing solid carbonaceous material, causing the gases, vapors and liquids` evolved vfrom the material passing through the coking stage to travel through the cool est portion of the material in said chamber into an olf-take passageway' and thence downwardly through said off-take-'pas'sagey way, and providing unobstructed passagef; ways in the body of material. in said chamber that lead from said off-take passageway outwardly through the coking zone so as to permit the escape of gases thatcontinue'to evolve from the material lying outside of the coking zone.

8. A process for distilling, carbonijzing 'or' vaporizing solid carbonaceous material, charchamber containing a continuous bodyof :solid carbonaceous -material, withdrawing v under reduced pressure the gases, vapors and liquids evolved from said materialA and causing said gases, vapors yand liquids to travel throughthe coolest portion of the ma# terial in said chamberandthence mmedif ately escapel from the apparatus and providing unobstructed passageways, consistlng of independent ducts, at numerous points throughout the material in said chamber for passing through the coking stage to travel through the coolest portion of the material in said chamber into a center take-oil' duct and thence flow downwardly through said take-olf duct to an eduction pipe and providing unobstructed passageways at numerous points throughout the body of material in said chamber in the form of independent ducts that branch laterally from said take-oli' duct through the continuous barrier in the coking zone and which prevent pressure from building up in the chamber outside of the coking Zone.

l0. A process for distilling, carbonizing or vaporizing carbonaceous material, char -acterized by applying heat externally to a *chamber containing solid carbonaceous material, causing the gases, vapors and liquids evolved from Athe material passing through the coking stage totravel into a center takeofi' duct through the coolest portion of the vmaterial in said chamber and through hollow members arranged at numerous points throughout the body of material in said chamber which form unobstructed passageways that'extend through the coking zone and establish communication between the "tak/e-of duct and the portion of said chamber lying beyond or outside of the coking zone, and causing the gases, vapors and liquids that enter the take-oli' duct to flow downwardly through same to an eduction fpipe. Y i

. GEORGE W. WALLACE.

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