US1948515A - Method of carbonizing solid carbonizable material - Google Patents

Description

W34 1. H. DERBY m M, ipgwwmfi METHOD OF CARBONIZING SOLID CARBONIZABLE MATERIAL Feb, 2317 Filed Jan. 4, 1930 l'Sheets-Sheet l gmantozs a w 115 Momma/v (It W1 0 ME) 2?; WM H, DERBY mm y *&

METHOD OF CARBONIZING SOLID CARBONIZABLE MATERIAL Filed Jan. 4, 1930 4 Sheets-Sheet 4 3w Si'Dwzi QM,

Patented Feb. 27, 1934 AT s r orr'ior.

METHOD or CARBONIZING sou omnonrzanna MATERIAL Ira H. Derby and Harold R. Homer, Indianapolis,

Ind., assignors to Peter C. Reilly, Indianapolis;v

Ind.

Application January 4, 1930. Serial him-118,612

11 Claims. (01. zoa -m) This invention relates to an improved method of and product produced-by the heating of carbonaceous materials under such temperature and such conditions as will yield the greatest amount' of valuable materials or substances such as condensates, a considerable carbon residue and certain gases, and this under minimum operating costs.

By carbonaceous material we refer to sfich materials as coal, lignite, Wood, 'oil shale, coal tar pitch, pitch coke, and such other materials that when heated yield certain of the substances or bodies just above mentioned.

By condensate we mean all the condensible volatile matter resulting from the distillation of the above named materials. By valuable condensate we mean the condensate from the above materials,'less its water content.

By gas we mean such substances as do not liquify under normal conditions.

The invention also has for one of its objects the production of a coke possessing special characteristics when coal is the carbonaceous material undergoing treatment. a

The process, in a generic sense, may be said to comprise the charging of a retort with the material to be operated upon; treating the upper layer of the charge for a period of time and at the necessary temperature to bring about the desired reaction or transformation in such portion of the charge; elevating the charge as a whole, and without substantial internal disturbance of the mass, to an extent suflicient to raise the material which has been transformed by the heating action to a point where it can be removed or sheared off from the underlying material; and carrying out such operations through a cycle until the entire charge within the retort has been treated, transformed and discharged.

While in the preferred operation of the apparatus to effect the process the charge is elevated step by step, still it may be carried. out by continuously raising the charge as a whole and without material internal disturbance thereof" and intermittently or continuously removing from the top of the charge that portion which {,een sufliciently transformed,

The process also involves the downdrawing of the evolved gases, vapors and fumes through the 50 charge in such a manner that the entire charge will be equally subjected to the action of such gases, vapors and fumes. I

In addition to the transformation of the material into carbonaceous residues of greater or less applicability such as, for example, the production of domestic coke from the carbonization of coal, certain valuable condensates are produced as well as gases which, as above noted, do not liquify under normal conditions and may be used for various purposes as for heating the retort and the material therein, or for various commercial purposes which will readily suggestthemselves. "During the carrying out of the process, when carbonaceous material which will fuse and cake when heated is employed, as for instance coals a5 ofcaking variety or coals that will fuse together, it has been found desirable to, in a sense, subdivide the charge. Such sub-division may be accomplished in several ways as will be hereinafter specifically set forth. This sub-division 7o prevents the mass from coalescing or caking to an extent such as to form a seal which would preclude a drawing of the generated gases and vapors downwardly and uniformly through the entire charge, as well as preventing the proper through flow of liquids. It likewise prevents the formation by the gas itself of a channel through the mass and through which the gas would pass without coming into effective working relation with the mass as a whole, In other words, we so propose to provide means for producing spaced channels extending downwardly through the entire body of the charge and through which channels the gases may be readily drawn. Such means likewise provides for a substantial even distribution of the gases in their passage downwardly through the charge with the consequent even action of such gases upon and throughout the entire mass.

Several embodiments of apparatus wherein the process may be carried out is shown in the annexed drawings along with a modified form of means for subdividing a charge with a view of securing even distribution of thethrough going gas in the manner just alluded to.

In the drawings, 7

Figure 1 is a side elevation of an apparatus wherein our process may be carried out: ":Figure 2 a vertical sectional view of the retort and the associated chamber for receiving the transformed material;

Figure 3 a detail vertical sectional view of theupper portion of theretort, the gates or valves employed to close off said retort from the receiving chamber and the chamber which houses the ram employed to dischargethe iinished product; I

Figure 4 a transverse horizontal section through the'upper portion of the retort;

- Figure 5 a detail sectional elevation of a heat 2 ass-ac exchange unit which may be employed in con junction with the finished product receiving chamber; and Figure 6 a sectional perspective view showing a modified form of the arrangement of the retort.

The construction shown in Figures 1 to 5 inclusive will be first described. In said figures the retort is shown as formed by an outer shell 1 lined with a refractory body 2, said retort being mounted upon a suitable foundation 3 which. as shown in Figure 2, provides a space or room 4 beneath the retort. In theform illustrated the retort is shown as rectangular but this is not essential so long as throughout its height it presents substantially the same cross area.

At its upper end the retort opens into a chamber 5, hereinafter denominated the combustion or conversion chamber. Said chamber is of a 'length greater than the width of the retort and at one side, Figure 2, houses a ram or pusher 6 normally closed off from the space, directly above the retort by a valve denoted generally by '7.

Said valve, see Figure 3, is mounted for reciprocating movement in a suitable'housing 8, .the lower portion whereof within the chamber 5 is fashioned 'to provide opposed valve seats 9 and 10. The valve, as shown in Figure 3, is of the two part ate type composed of leaves 11 and 12 pivotally connected at their upper ends to a piston rod 13. The rod is attached to a piston 14 mounted for reciprocation in an hydraulic cylinder 15 into which extend mains 16 and 17 connected to any suitable source and controlled byvalves not shown.- Leaf 12 carries a refractory face or element 18 and leaf 11 is cut away so that the refractory face extends through the valve and protects all the metal parts from the heat of the combustion chamber. When the valve is lowered the lower portion of the leaves contact a wedge-shaped element 19 which spreads the leaves apart, 11 acting as a. .wedge and '12 sealing off the chamber in which the ram 6 ismounted.

A clean-out door or opening 20, will preferably be provided below the member'19 in order that the valvechamber or housingmay be kept clear of foreign material. A similar valve is provided at the right hand side of the upper portion of the retort and inasmuch as the parts and the erated from'an hydraulic cylinder 23 provided with suitable inlet and discharge pipes not shown.

In the upper wall of the chamber, directly over the retort proper, there is provided a man-hole 24 normally closed during the operation of the retort by a cover 25. Above said man-hole is a' hopper 26 to which the material to be .treated is fed inany suitable manner, as for'instance by an endless conveyerx 2'7, Figure 1.

The lower part of the hopper is provided with a gate 28 of conventional form which will, of course, be closed when the retort is charged to the necessary degree after which the cover 25 is again replaced. I

The finished product chamber 21 is likewise provided with e man-hole 29 normally closed by a cover 30. At its lower end it is provided with a discharge gate 31.

Mounted within the chamber or space 4 below off-take 35'opens into the upper portion of this space or chamber 34, said off-take being connected with any suitable source of suction, as for instance a gas booster or exhauster 36 shown more or less diagrammatically in Figure 1. A drain for tar or other resulting liquids opens into the lower portion of the chamber 34, such drain being indicated by 37. The main leading from this drain maybe connected to any suitable form of apparatus, as for instance tar separators or the like not shown.

Mounted for reciprocation within the retort is a false bottom or lift 38. Said member is mounted and secured upon the upper-end of a piston rod 39 which extends into an hydraulic cylinder 40 having suitable mains leading into the same to bring about the necessary and desired recipro-.

cating motion to the lift or false bottom 38.

Extending upwardly from the pan'and passing through openings formed in the false bottom is a series of rods or members 41, said elements extending upwardly within the retort to a point near the upper end thereof. These members, in the operation of the process,- tend to produce channels through the material down which the evolved gases and vapors are drawn. In the coking zone the ducts formed by the rods or spacers remain in the plastic coal and-persist through to the surface of the charge as shown in Figure 2 at 60. As will be appreciated, the members remain in a fixed position being supported at all times from the pan located within the chamber 4. As the false bottom or lift 38 is lowered the material is charged intothe retort and fills the same and the rods are surroundedthereby.

Instead of employing fixed rods or spacers 41, as above set forth, the charge may otherwise be subdivided so as to produce channels. Thus, for

. instance, in the upper part of Figure 4 instead of employing rods or spacers we have shown paper or cardboard tubes, as 42, filled with inert material, such for instance as ground coke produced by the present process. These tubes are positioned within the retort with their lower ends upon the false bottom 38 and the material to be treated is charged into the retort around such tubes. Thus it will be seen that the formation of .channels within the charge maybe produced in various ways and we do not, therefore,

bustion chamber 5 and onto the top layer of the material therein, heating it by contact with the hot combustion gases as well as by radiation. The heating is accomplished in this latter manner with the highest thermal efiiciency.

Where a non-condensible gas of highca1orific loll 86 I ondary blower, not shown, is then started and the burners 43, '44 function as imfiormal pracvalue is desired inplace of a largeramount of low value gas, it is within the scope of this insame point, namelyat the level or substantial level of the ram 6. This method'of charging the retort eliminates the outward pressure against the spacers 41 that would be produced by the falling coal. In other words, the section of the coal just'above the'end of the members 41 has already come to rest with respect to its lateral motion before it comes into contact with said members. After the retort is charged the exhauster 36 is started causing a reduced pressure throughout the system and retort. This reduced pressure is regulated at the combustion chamber 5 and undernormal operating conditions from 13 in. of water is maintainedat this po nt. The reduced pressure in the combustion chamber 5 acts similarly on a gas, pulverized, or liquid fuel burner, as does external air pressure in an ordinary burner.- It is also possible to operate the retort on atmospheric or sl ghtly positive pressure with the addition of a blower on the air line to the burners. The exhauster 36 is slowed down causing the reduced pressure to drop in the system until the vacuum in the combustion chamber 5 is reduced to zero. The sectiee. The vacuum in the remaining parts of the system remainsthe same, that is, 1 to 3" of water. Inasmuch as such burners form no part of the present invention it is not deemed necessary to illustrate the e in detail.

The fuel mixture in'"the eombustion chamber is ignited in the usual manner and by regulating the valves, either automatically or by hand, all the variation of combustion from a slow lazy flame with an excess of carbon monoxide and unburned hydrocarbons to a lean flame with an excess of oxygen may be obbtained. In this manner the temperature of d stilation and jcarbonization is controlled. The combustion gases, following their formation in the combustionchamber, play down and into the underlying mass, giving up their heat very rapidly to the top layer thereof. Where say coal is the material being'transformed this upper layer reaches a temperature of approximately 100 C. in are'atively short time, approximately five mnutes,

and is held at this temperature throughout the run. It is to be understood, however, that we do not wish to limit-ourselves to'the particular temperature just specnied but in the treatment of coal we have found that 700 C. is an-efllcient operating temperature. At this temperature the coke produced in the upper layer contains approximately 10% to 15% volatile matter whch makes it a desirable domestic fuel since it burns with'a smokeless flame and is easily ignited.

' The gases, as they aredrawn down through the mass, give up their latent heat very rapidly. In the upper layer of the material, and which may be termed the coking zone, a distilling temperature of 350 C. is very quickly obtained and within a period of 30 minutes, more or less, the ma-. terial in this zone has been completely coked and brought to an average temperature of approximately 600C.

This rapid coking, due to the rapid heat trans-. fer in the first or coking zone, taking place on properly conditioned and pre-heated coal, acts to form a firm hard coke at the temperatures above given. This behavior characterizes not only the commonly called caking coals, but also the non-caking coals and makes our process especialy valuable for the treatment of low grade Indiana and Illinois .coals.

The coking zone is indicated on Figure 2 in the space denoted by a. Below is what may be termed a distilling zone, indicated by b, and beneath is a drying zone, indicated generally by c.

The combustion gases with the products of distillation from the first or coking zone a passes on down through the distilling zone b. Within this zone the rise of temperature is much slower than in the upper zone 'and only reaches approximately 400 C. at the end of 60 minutes distillation; This is no doubt partly due to the fact that a large percent of distillate comes off at 400 C. from the first zone andwashing down into the second zone tends to equalize the temperature at this point. This is also due to the fact that the latent heat in the gases has been partially absorbed in the first zone. zone c is still slower in approachingthe distilling temperature due to the same causes. The combustion gases and products of distillation thus pass from this lower zone through the remaining mass gradually raising the temperature and drying the lower portion of the mass and finally, at a'relatively low temperature, 50-100 C., passing through the perforations in the false bottom 38 into the chamber 34 underlying. the false bottom.

A large part of the condensate comes out the lower portion of the mass due to the good condensing effect of the coal mass as a whole. The gas passes through the chamber 34 into gas main 35 through which it may be led to a condensing system, not shown, where the final-separation of condensate and noncondensable gases is made, while the tar passes through main 37.

When coals of the caking variety or coals that will fuse together with coking are used it has been found desirable to use the spacer rods or to sub-dividethe charge by the interposition of inert material, as above set forth, to produce channels to bring about an even distribution of the gases throughout the mass. In coking a seal is apt -ing an undesirable coke. The remainder of the charge, which does not come into direct contact with such combustion gases, will naturally not progress of heat obtains throughout the retort.

Where channels are artificially and initially produced by the rods or by the inert spacing or division of the charge by such spacing the downflowing gas acts to heat the charge evenly or substantially so throughout its entire mass. The exposed materials within the channels act similar to surface heaters and pick up theheat from the combustion gases and dissipate it to the charge The third or drying be heated to the same degree and an uneven by conduction and convection. This effect is most pronounced in the first and second zones or layer is moved to the dotted line position shown' in Figure 2 free of the walls of the retort. At this time it extends into the chamber 5 between the then lowered valves or gates 7 and 7 The false bottom is then brought to rest, the gates elevated and the ram 6 moved from the position shown in Figure 2 to the right, shearing oil the finished charge and forcing the same to the coke receiving chamber 21. The ram is then retracted, the

valves or gates then lowered and the operation of carbonizing is continued. This cycle is continued until the entire charge has been treated. The recharging of the retort proceeds simultaneously with the lowering of the lift as previously noted.

As will be appreciated, instead of raising the false bottom step by step it may have a continuous motion, relatively slow, and the ram 6 may be periodically operated.

Where a coke of exceptional hardness is desired, coal tar or a coal tar pitch may be introduced into the combustion chamber and onto the top layer of the charge. It may be introduced through the burners and distributed by the combustion gases or through supplementary tuyres not .shown. This material acts as a binder and the" combustion gases coke the coal mass and coal tar at the same time. The coal tar coke forms in the pores of the coal coke and makes an excep tionally hard coke from the poorest of Indiana non-caking coals. Similar beneficial results may be obtained by using a rich fuel mixture of pulverized coal. A part of the coal will burn but a part will be at the soft, plastic stage when it reaches the top layer of coal that is being treated in the retort. This soft, plastic dust will unite with the forming coke and add materially to its structural strength.

The temperature obtaining within the retort and the various zones may be determined by thermo-couples and in Figure 2 there is indicated two thermo-couple wells and 46. Any number of such wells may be employed.

The heat from the coke transferred to the chamber 21 may be utilized by the employment of any suitable heat exchange means. In the drawings we have shown a chamber 4'? connected at its top to the upper portion of the coke receiving chamber 21 by a pipe 48 and its lower end connected by a pipe or conduit 49 including a suction fan 50. A coil 51 passing through the chamber 47 and forming a conduit for water or other medium absorbs the heat of the gas or air drawn out of the chamber 21. This not only utilizes the heat but cools the coke so that it may be discharged from the chamber 21 at relatively short intervals.

In Figure 6 there is shown a section of a retort wherein, instead of employing rods to bring about the subdivision of the charge with a View of producing initial channels for the downward passage of the gases, a retort, designated by 52, is provided with a series of spaced vertically disposed partitions or walls 53 between which the material to be treated is placed. In this instance instead of having a single movable bottom or lift to elevate the charge there is provided a false bottom as 54 for each of the spaces between the partitions 53 or the outermost partitions and the adjacent wall of the retort. These members are supported by uprights 55 extending upwardly from a head 56, which latter is designed to be raised and lowered by a ram, designated generally The channels, however pre-formed in the charge, insure a proper distribution of the downgoing gases. Moreover, such channels act as centers for the radiationof heat which passes into the charge acting thereon throughout the various zones and thus bringing the mass to a condition such as when it reaches the combustion zone only a minimum of heat and time need be employed to convert the mass.

The coke produced by the method as above set forth has certain characteristics which clearly identify it and render it valuable for various purposes. The coke as discharged may be said to be highly coked and low in volatile adjacent the point where the gas is passed down through a channel. At a point removed therefrom it may be said to be coked to a lesser degree and relatively high in volatile content. Stated in another way, a piece of coke formed between two channels would be at the channel portions thereof highly coked and low in volatile whereas in the intermediate portion it wouldnot be so highly coked and would contain more volatiles than the other portion.

Under the process as practiced in accordance with the above showing it has been found that we can secure a larger yield of tar than obtains with any other method of which we are aware. This is due to the fact that the tar is removed from the zone of distillation as rapidly as produced without to any extent bringing the tar vapor into contact with any material that is above the temperature at which it is produced. This eliminates any decomposition oi the primary distillate. With our process we have secured a yield as high as 33 gallons per ton of coal.

The process also brings about a rapid rate of distillation. In ordinary coking practice the advance of a given isotherm is at the rate of one inch per hour. Under our process, when operating with an apparatus as above described, a composite advance of ten inches per hour obtains.

While we have described the method more specifically in connection with coals, sti l it is appllcable to the treatment of other carbonaceous materials above specified.

What is claimed is:

1. That method of treating solid carbonizable material to distil and carbonize the same. which comprises formin a char e thereof and likewise producing a plurality of channels extending therethrough so spaced as to bring about substantially equal distribution of heat; subjecting the upper exposed surface of the charge through which the channels open to the direct action of a gasecus heating medium: and drawing such medium, together with distillates evolved in the treatment of the charge. down through the channels in the charge and in direct contact with the material of the charge.

2. That method of treating solid carbonizable rec . material to distil and carbonize the same. which comprises forming a charge thereof and likewise'producing a plurality of spaced channels extending therethrough; subjecting an exposed surface oi. thecharge through which the channels open to the direct action of a gaseous heating medium to carbonize a layer at and adjacent the exposed surface, such heating medium and the evolved distillates being drawn through the channels and in contact with the mass, thereby preheating and partially carbonizing the remainder of the mass; removing the carbonized layer to expose a new layer or surface of the material to v the direct action of the fluid heating medium; and

, the remainder of the material and in contact material.

therewith to partially carbonize the same; removing the carbonized layerof material formed upon the upper surface of the charge; and repeating thecycle of operations on the remainder of the i 4. That method of carbonizing a'body of coal to produce coke, which comprises subjecting the upper portion of such material to the direct action of combustion gases to rapidly'distil and carbonize that portion; drawing such gases, together with evolved distillates, downwardly through the body being treated and thereby heating and partially carbonizing the underlying portion of the body; removing the upper coked portion of the body; moving the remainder of the partially carbonized material bodily towardthe source of combustion gases and thereby presenting that portion of the body from which the coked portion has been removed to the direct action of such gases; removing such portion when coked; and

continuing such cycle of operations, whereby the successive removal of the coked portions allows direct access of the gases to the partially carbonized charge after each of such removals for the purpose of rapidly carbonizing the charge.

5. That method of carbonizing'a body of coal to produce coke, which comprises charging the same into aretort and producing a plurality of I spaced channels extending through the charge within the retort; subjecting the upper portion of such charge to the direct action of a gaseous heating mediumto rapidly distil and carbonize that portion; drawing such heating medium, to-

. gether with evolved gases, downwardly through the channels formed in the charge, thereby partially carbonizing the underlying portion of the charge; removing the upper coked portion of the charge; moving the remainder of the partially carbonized charge bodily toward the source of the heating medium and thereby presenting that portion of the chargefrom which the coked portion has been removed to the direct action of such fluid heating medium; removing such portion when coked; and continuing such cycle of .operations, whereby the successive removal of the coked portions allows direct access of the fluid heating medium to the partially carbonized charge after each of such removals for the purpose of rapidly carbonizing the charge.

6. That method of treating a body of fusible carbonaceous material to distil and carbonize the removing the upper coked portion of the charge;

moving the remainder of the partially carbonized charge bodily .toward the source of heating medium and thereby presenting that portion of the charge from which the coked portion has been removed to the direct action of such heating medium; thereafter removing such portion when coked; and continuing. such cycle'of operations,

whereby the successive removal of the coked portions allows direct access of the heating medium to the partially carbonized charge after each of such removals for the purpose of rapidly carbonizing the charge.

'7. That method of treating a body of solid car- 'bonizable material to distil the same, which comprises charging the body into a retortand pro- 'ducing a plurality of spaced channels extending through the charge within the retort; subjecting the upper portion of such, charge to the directaction of a gaseous heating medium to rap- .idly distil that portion; drawing such heating 'medium, together with the matters driven oif, downwardly through the channels formed in the charge and thereby heating the underlying portion of the charge; removing the upper treated portion of the charge; moving the remainder of the charge bodily toward the source of fluid heating medium and thereby presenting that portion of the charge from which the treated portion has been removed to the direct action of such heating medium; thereafter removing such treated portion; and continuing such cycle of operations, whereby the successive removal of the treated portions allows direct access of the heating medium to the partially treatedcharge after each of such removals.

8. A method of treating a mass of fusible carbonizable material to distil the same, which consistsf in forming distinct channels extending 1 through the mass by placing the mass around a plurality of separate bodies of granular material, said granular material being infusible at the temperature employed in carrying out the method and said material serving to maintain the integrity of the channels throughout the heating operatic said channelsbeing likewise so spaced as to bring about-a substantially equal distribution of the heat; and drawing a gaseous heating medium through said channels thereby distilling the mass.

9. That method I carbonizable material to distil and carbonize the ftreating a mass offusible b same, which consists in forming distinct chanwhich the channels extend; and drawing such heating medium with the evolved distillates through said channels and in direct contact with the material of the mass thereby'heatingjthe same;

Bit

10. That method of treating a mass of carbonizable material to heat and carbonize the same, which consists in charging the material around a plurality of stable spacers that extend through the mass, thereby forming channels between the mass and said spacers, the spacers being so located as to bring abouta substantially even distribution of heat in the mass; generating a gaseous heating medium in contact with a surcomprises producing a plurality of separate and spaced channels extending through the mass, said channels being so spaced as to bring about a substantially equal distribution of heat throughout the mass; subjecting the upper surface of the mass to the action of a gaseous heating medium; drawing said heating medium directly through the channels and in direct contact with the material of the mass, thereby causing absorption of heat from the medium and directly transmitting it to the mass; and providing solid material extending throughout each of said channels for maintaining the same open throughout the entire operation.

' IRA H. DERBY.

HAROLD R. HORNER.

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