US2086561A - Apparatus for revivifying spent decolorizing materials - Google Patents

Description

July 13, 1937.

C. G. KOEPPL APPARATUS FOR REVIVIFYING SPENT DECOLORIZING MATERIALS Filed May 3l, 1934 4 Sheets-Sheet l @GYM ATTORNEY C. G. KOEPPL July 13, 1937. 2,086,561-

APPARATUS FOR REVIVIFYING SPENT DECOLORIZING MATERIALS 4 Filed May 31, 1954 4 Sheets-Sheet 2 Aff INVE TOR aa( /ffff/f/ M A TORNEY July 13, 1937. C, G, KQEPPL 2,086,561

APPARATUS FOR REVIVIFYING SPENT DECOLORIZING MATERIALS Filed May 51, 1934 4 sheets-Sheet 3 iff-l INVE TO @7g/W C. G. KOEPPL July 13, 1937.

APPARATUS FOR REVIVIFYING SPENT DECOLORIZING MATERIALS Filed May 3l, 1934 4 Sheets-Sheet 4 "Il, fill/l 'III' I Il ,I l

INVENTOR 1 xmsw TTORNEY l--latemed July 413 '1937 .APPARATUS Fon REvrvlFYING sPEN'r DE- COLORIZIN G MATERIALS Carl 1G. KoeppL-New York, N. Y., assignor of onehalf to Anthony -William Deller, New York,

The present'invention relates to a process of revivifying spentv decolorizingand/or purifying material, and more particularly to an improved methodj of roasting spent decolorizing and/o1 5 purifying material by indirect heat and to a new and improved apparatus therefor. A

It is well known that heretofore decolorizing and purifying-materials, such as clay, were used -to decolorize and/or purify liquids, such as minv eral oils, lubricating oils, gasoline, kerosene and the like. In this process clay or similar material absorbed and/or adsorbed contaminating substanceswhich colored and which rendered the liquid impure. After the clay had been used for a l5 "period ofv time it was saturated with the contami.

' natingsubstances and did not have any further power. to decolorize and/or purify liquids, such :is-hydrocarbons or other organic liquids. vIt was then necessary'to revivify the spent clay in order to make it'.usefu1forfurther treatments. Generally, the spent `clay was fed to a furnace where it was heated by direct contact with hot `gases and/or with direct contact with a flame l from a burner.

lWedge type through va feeder nozzle or other feeding device. The clay fell upon the top hearth of the multiple hearth furnace and was then car-,-

ried from one hearth to a' lower hearth by means 30 of teeth or plows which were secured to rabble arms. As is well known these arms were secured vto a single vertical shaft which extended through the center of the furnace from the top vto the bottom and which was rotated in a suitable' man- 3511er, such as by meansV of a set of gears connected I to an electric motor. In other words, the clay in its downwardl travel through the multiple hearthfurnace fell through ports located on the periphery of the "out-hearths" and through cen- 40 tral ports on the in-hearths.

`Associated with each hearth or with alternate hearths vor with special hearths, burners were provided by means of `which the clay'was heated' g and roasted by direct contact with the flame from -45 the burner and by direct contact with the hot gas generatedthereby. The direct impingement of the flame on the clay drove off the volatile compounds,4 such as hydrocarbons, and roasted- Thus, for instance,. spent clay 25 was fed to a roasting furnace of the Herreshoif orl l' nppiiationmay 31,1934, serial ivm-'128,298

' i'ciaims.. (o1. 2oz- 124) v In burners of the multiple hearth type, it has been possible toobserve zones of heating where the openflame of the burner directly impinges on the clay. In these prior procedures any hydrocarbon, such asnaphtha, mineral oil, gasoline, kerosene and the like, were ignited and burned at; the surface of the clay. The burning y of these hydrocarbons increased the surface temperature and tended to sinter the clay and to convert at least a part thereof to a sintered condition. It is well known that the filtering eiEl-l the recovered material was of greatly reduced eiliciency. Alfter each revivifying' cycle or passage through the multiple hearth furnace, the filtering eciency of the clay was steadily and rapidly reduced and nally was so low that the clay could-not be used at a profit.' Although many attempts were made to remedy the foregoing shortcomings, the proposals, as far as Iam aware, only provided procedures wherein the clay could be used only a very few times before it had andl became practically valueless as a commercial decolorizing and purifying material.

I have discovered a procedure by means of which the shortcomings notedy hereinabove can be avoided-and by means of which spent decolorizing and/or purifying materials can be revivied efficiently without detrimentally affecting the decolorizing and purifying efficiency.

It is an object of the invention to provide a procedure involving the indirect heating of the Aspent decolorizing and/or purifying material and the isolation of the flame and heating gases from impinging directly upon, coming in contact with,

"contaminating the spent material'under treatment and at Athe same time eliminating slack losses of nes, amounting to- 20 to 30% of the clay. y

It is another object of the invention tov provide a process forindirectly heating and roasting spent material and to evaporate the volatile substances, such as oil, naphtha or the like, without detriwmentally effecting such substances and withoutv burning or contaminating them wherebythe evaporated substance, such as oil, naphtha and Alost its absorbent and/or adsorbent properties the like can be recovered as valuable by-products. It is a further object of theinvention to provide a process of indirectly heating and roasting spent decolorizing material and to transfer heat to said' artificial inert atmospheres, steam, or products of combustion.

It is also an object of the invention to effect the oxidation of the carbonaceous matter to complete the revivification of the material after distillation of hydrocarbon impurities by spontaneous combustion with air without sintering or lotherwise impairing its 'decolorizing and purifying efficiency and without the presence of steam, or other additional inert atmospheres.

It is within the contemplation of the invention to provide an improved and simple apparatus for carrying the present invention into practice which has a combustion chamber to provide the heat necessary for the distillation of the adsorbed hydrocarbons, a zone of distillation associated with and isolated from the combustion chamber to prevent the products of combustion from coming in contact with, and contaminating the products of distillation, and a zone of oxidation associated with, but substantially isolated from the zone of distillation to prevent the air from mixing with the products of distillation. l q

Moreover, the invention contemplates providing an apparatus 'in which the material to be treated flows by gravity in a substantially continuous manner, and which is capable of treating different vmaterials simultaneously and independently from each other. I

Other objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 illustrates diagrammatically a vertical section of an apparatus embodying the present invention and capable of carrying the present procedure into practice.

Figs. 2, 3, 4, and 5 are sectional views taken on lines 2 2, 3 3, Il 4A and 5-5, respectively, of Fig. 1. Y

Fig. 6 depicts an enlarged elevation view with parts broken away showing more in detail a zone of distillation and heat .exchange devices near line 3 3 of Fig. 1.

Fig. 7 shows aperspective view with parts broken away of a helical conveyor near line 4& 4 of Fig. 1; and

Fig. 8 illustrates a perspective View with parts broken away of a water cooled helical conveyor near line 5 5 of Fig. 1.

In general, the apparatus shown in Fig. 1

comprises several zones, every one of which is so designed and controlledas to perform a certain function and to effecta certain desired result on the material to be treated. 'Ihe zones are contiguous and superimposed sections of the appa-A ratus which for purpose of illustration may be classified as the feeding zone, the preheating zone,

. the zone of distillation, the zone of oxidation, 'the cooling zone and the discharging zone.

In particular, the apparatus or furnace may be a fabricated steel structure comprising a plurality of vertical membersk 9 and cross members I0 welded or riveted together, in which other parts and sections of the apparatus are properly ,fitted and supported.

The charging zone comprises a `plurality of charging hoppers Il, located over the upper end of the structure fo'r the purpose of charging the clays or other materials to be treated into the apparatus. The material may be fed to hoppers II by any conventional charging device, not shown in the drawings, such as by automatic skips or buckethoists, or it may be stored in stationary bins located over the hoppers-and be released as required. vThe hoppers extend through the roof of the apparatus into the preheating zone and feed the material to a plurality of inclined chutes I2.

The preheating zone, which constitutes the upper part of the apparatus, may be an insulated or refractory lined chamber provided with a plurality of inclined stationary chutes I2. v Chutes I2 convey the material to be treated from charging hopper II to ports I5 at the bottom of the chamber, and discharge over a pluralityof helical, or spirally wound stationary chutes I8 which extend vertically through the rest of the apparatus from the bottom of the preheating zone, and discharge into discharge hoppers 3| at the lower end of the apparatus. It is to be observed that chutes I2 and I8 provide direct paths for'the material to be treat-ed which are independent from one anotherand are capable ofv being charged and discharged separately, andv in which the material flows by gravity alone. Ports 22 equipped with doors 23 and peep holes 24, are provided in th'e sides as a means of inspection and of access into the preheating chamber. Reference character I3 designates outlets, preferably at the top of the apparatus, for' the withdrawal of the products of distillation from the preheating chamber and from the zone of distillation. In connection with outlets I3, it is preferred to have means, not shown in the drawings, for collecting and for condensing the products of distillation. Other methods for conveying the material through the?` products ofdistillation, the combustion chamber is sealed from the adjacent zones and from the interior of tubes I9, and it divides the apparatus except for tubes I9 which connect the upper preheating chamber to the lower chamber of oxidation and provides a passage for helical chutes I8. An eifective way of sealing tubes I9 may be provided by iiaring out and turning down the upper ends of the tubes to fit lute rings 31 sunk into the upper surface of roof I4, while'the lower ends of the tube t into lute rings 38 sunk in the upper` surface of bottom 39 bf the combustion chamber.

In order to ktransmit the heat more efliciently to the material under treatment traveling over chutes I 8 in tubes I9, the tubes are preferably,l made to fit tightly over chutes I8 to provide actual metallic contact, and the outside surface Vof the tubes are provided with heat exchange rig-ht angles. This-would-increasethe radiation contact surface between the tubes 'I 9 and 'the chutes IIlV and also prevent any clay from forming an insulation medium in case some voi' the clay 'may' accumulate between the chute and the tube.

Tubes I9 may be made of a heat resistant metal or ofthermal refractory material, such as silicon carbide. Heat exchange devices 2li may be made of similar material and they may be fabricatedA as an integral part with tubes I9 or separately to lit over the tubes. 1

The combustion chamber may -be' red-by- Y burners 25, for instance, of the tunnel type Awhich conne the combustion of the fuel in tunnel 26 and convey the heat into the chamber by means of thehot gases of combustion. A more emcient and more uniform distribution of heat to alltubes f' I9 may be obtained and cold spots may be avoided by dividingthe combustion chamber in three or more sections by means ofballles 4I extending horizontally across the chamber and having ports .42for the products of combustion at alternate opposite ends of the sections. By placing burners 25 at one side of the lowest section of the combustion chamber, and outletrue 21 at 'one side of the uppermost section, the products of combustion are made to ow'horizontally in each section past all tubes I 9, and the direction of flow is reversed in each successive upper section, until the outlet flue is reached.- It is to be observed that besides equalizing the distribution of l heat in tubes I9, bailles 4I also establish a temperature gradient which is opposite to the direction of ilow of the material, the temperature being 'higher at the lower than at the upper end of tubes I9. Other sources of heat may, however, beadopted,

as for instance by winding tubes I9 -with electrlcally heated resistance wires, or by' electric induction.

It is to be noted that the preheating chamber is supplied with heat from the combustion chamber by radiation thrugh roof I4. kAk more elcient u'pward transfer of heatto the preheating chamber may be obtained by providingA roof I4 with heat reilectors or' ports II sealed by radiation platesvl, which may be made of any suitable heat resistant metal or of thermal refractory, such as silicon carbide. Ports 22- with doors 29 and peep-holes 'Mv arel provided at the sides for the purpose of inspection or admission into the combustion chamber when repairs or replace` ment of parts are necessary.

Immediately below the combustion chamber lies thev zone of oxidation which consists of an insulated chamber having a plurality of ports 12| at the top and a corresponding number of ports 39 at the bottom for helical chutes I8.l The' oxygen necessary for the burning out of the carbon, left ony the material after the distillation.

treatment in tubes I9, is provided by circulating a suitable amount of air in the oxidation cham- I ber vthrough air inlet ports 28 at the bottom and large outlets 21 at the sides of the .chamber near the top. The circulation of theair may beinduced by any conventional method, and the amount may be controlled, for instance, by sliding valves 29 in inlet ports 28. It is to be observed that by restricting ports 2l at the bottom.

of tubes I9 to a size. just suflicient for the free iiowing of the material, and-by making air outlet flues'21 suiiiciently large, the velocity of the air is maintained at a relatively low figure, and the tendency for'thev air to rise to the upper parts of the apparatus above the oxidationv chamber is practically eliminated. In traversing the oxida- J aoeauei lchutes I9 in theoxidation chamber.

pendently in any -cooling tion'chamb, helical chutes la are not enclosed in tubes, but are preferably left open in order to provide free contact between the airand the material. Fig. 'I shows in detail the construction oi' It is observed that the material is prevented from fallingroff the chutes by having the outside edges of the helical plates turned up at right angle. The

' oxidation chamber is also provided at the sides with ports 22 to allow admission into the chamber' when repairs or replacement of parts are necessary. Ports 22 are -kept'closed by doors 23 which are equipped with peep holes 24.

The cooling zone vmay consist of a plurality of tubes 30 enclosing spiral conveyors I8 and extending from ports 39 at the -bottom of the oxidation chamberv to hoppers 3|' which may discharge the treated material to-cars or to station- 1 ary bins, or to any other suitable device. A more rapid cooling of the material may be effected by ..tice, the material to be treated is fed vto the fur,- rnace through hoppers II, whereby it flows by gravity .on chutes I2 through the preheating chamber andon helical chutes I9 downwardly ,through the rest of the apparatus to discharge hoppers 3l. The flow of the material under,

treatment is continuous and is such that the process is substantially under-control throughout thevarious stages of the operation'.

In flowing through'the preheating lzone, the material is heated by heat radiating through the roof of the combustion chamber and is suitably prepared so. that-it may be acted upon more readily without tending to unduly cool down the next zone, or the zone of oxidation. Some of the lighter oils, such as naphtha may also begin to volatilize in the preheating chamber.

- Active distillation and decomposition of substantially all the-impurities adsorbed by the clays,

however, occurs while Athe material flows through tubes I9. f 'I'he naphtha and the lighter oil are rst removed by distillation at the upper parts of the tubes, flow upwardly into the preheating chamber, and are recovered via outlets I3.

progressing further down towards the vlower end of the tubesI the material is progressively heated to higher temperatures, and the heavier hydrocarbons, such as asphaltic and bituminous matter, are decomposed and distilled o .if leaving a carbon deposit on the particles composing the material. 'I'he lighter products of distillation ilow upwardly and pass into'the preheating chamber whence they' are also withdrawn via outlet I3 to an appropriate recovery system'forA the re.- covery of naphtha, oils and the other vapors. The height and the temperature of the zone -of distillation are so controlled as to effect the chstllation ofesubstanlzially all the hydrocarbon impurities in the material under treatment, without,

. however, dehydrating or causing the loss of the combined. water of the material itself. It is to be observed from the construction of the apparatus thatthe highest temperature is maintained at the lower end of tubes I9 in which active distillation takes place and that the temperature gradually decreases upwardly towards the preheating chamber, thus establishing a thermal gradientl opposite to the flow of the material. The temperature of the lower end of tubes I9 is preferably kept at approximately 950-1000 F. for new clays (second to fth burns), and approximately 1000 1050 F. for clays which have been treated several times. 'I'he temperature of the upperpart of tubes I9 is kept at about 300 F., while the preheating chamber is maintained at a suicientlyhigh temperature to avoid the condensation of the products of distillation. If desired, thermo- .static devices may be employed to maintain any selected temperature in the combustion chamber, spirals, etc.

When entering the oxidation chamber, the material consists of hot particles from which the adsorbed hydrocarbons have been substantially removed by distillation, but which are covered withcarbon resulting from 'the decomposition of some of .the heavier hydrocarbons. The temperature, however, is suiiiciently high, about 1,000"y temperature of the particles is not very high,

about 1000`F., and since the particles are moving towards an increasingly cooler zone, and against a counter-current ilow of cold air, any excessive rise in temperature tending to cause fusion or dehydration of the particles is substantially prevented. The rate of burning of carbon may further be controlled by controlling the amount of air ilowing in the oxidation chamber. 'I'he residual air and the products of combustion of the carbonaceous matter are withdrawn through outlet ues 2'I which are sufficiently large to keep the velocity of the air at a relatively low value, thereby preventing the gases from entering tubes I9 and contaminating the products of distillation. l

In flowing through tubes 30, the material may finally be cooled down to any desired temperature by controlling the ow of water inthe cooling plates, so that it may be conveniently handled when discharged by hoppers 3l.

It is to be observed from the foregoing description that the invention affords an improved, rapid and efficient method for the revivification of spent decolorizing material used in the rening of mineral oils, or the like, in which the distillation of the adsorbed hydrocarbons is carried out without the aid of any artificial inert atmospheres, or of steam, and without contamination by the products of combustion. The naphtha and the other products of distillation are recovered in a substantially pure state and with practically little losses, while after treatment by the invented process the material has retained sub- Ystantially intact its cellular structure free from adsorbed matter or carbon of decomposition, and its adsorptive properties have been practically restored. The material moves through the apparatus by gravity alone without the aid of any external motive power, and in a steady stream like the ow of a fluid material. The material `substantially pure condition.

cannot accumulate at any stage of the process, and in following a tortuous path is continually turned over exposing fresh parts to be acted upon,

' thereby insuring a more uniform and more rapid treatment of all its parts.

It is also to be observed that the invention provides an' improved apparatus in whichthe process is carried out in a very rapid; efficient and economical manner. Special features of the apparatus are its simplicity of construction, the absence of any moving parts, and its flexibility of operation,` which enables it to treat different materials simultaneously and independently from each other. The capacity of the apparatus can easily be increased by extending one side to in-k clude an additional number of separate chutes or paths for the material or, if desired, can be extended vertically.

Although the present invention has been described in connection with the revivication of clays, it is to be understood that other materials may be treated and that a great variety of chemical and metallurgical procedures may be conducted in the furnace. As those skilled in the art will readily understand, modifications and variations may be resorted to without departing from the spirit and scope of the invention. Thus, for instance, the apparatus may be used for the regeneration of sugar house-bone' black, activated carbon, charcoal,l etc.,` or for the calcining of limestone, whereby burnt lime is produced and carbon dioxide is recovered in a It is understood that when treating a substance such as limestone from which volatilizablesubstances may be removed without leaving a residue of oxidizable products of decomposition, the oxidation chambermay be omitted from the construction of the apparatus and the cooling zone may be made to extend up to the heating 'zone thereof. Then again movable screws can be provided instead of stationary helices, or conical tubes may be used instead of cylindrical ones.

I claim:

l. An apparatus for revivifying spent decolorizing materials comprising a plurality of vertical stationary conveyors conveying the material under treatment through the apparatus, means for feeding said material to the upper end of said conveyors, a metallic tube of high heat conductivity for each of said conveyors surrounding the 'upper' portion thereof, means for collectively heating the outer surface of said tubes to cause indirect heating of the material within said tubes and to volatilize volatilizable substances therefrom, means for withdrawing said volatilized substances free from products of combustion, means for flowing air around an intermediate portion of said conveyors at a level lower than said tubes to cause combustion of carbonaceous substances in said material, and means .for cooling the lower portion of said conveyors chutes to air to cause combustion of carbonaceous substances contained in the material, and means for cooling .the lower portion of'said chutes to cool the treated material before discharging.

3.` An apparatus forrevivifying spent decol orizin'g materials comprising a plurality of vertical stationary helical chutes for conveying material to be treated through the apparatus, a heat exchange tube for each of said chutes enclosing the upper portion thereof, a combustion chambersurrounding said'tubes to indirectly heat material on said chutes and within said tubes,v means for withdrawing volatilized substances from said tubes free from products of combustion, an oxidation chamber underlying the combustion chamber and directly surrounding an intermediate portion of said chutes, means for isolating said oxidation chamber from the combustion` chamber, means for admitting air into the oxidation chamber to cause combustion of carbonaceous substances in said material, and means for cooling the lower end of said chutes to cool the revivified material before discharging. 4. An apparatus for revivifying spent decolorlzing materials comprising a plurality of vertical stationary helical chutesl for conveying the material to be treated through the apparatus under the action of gravity, means for separately feeding and discharging said chutes, a combustion chamber enclosing an upper portion of said chutes, means lincluding av heat transfer tube around each of said chutes for isolating said upper lportion of thevchutes from the combustion chamber and for transferring heat eiiiciently and uniformly to the material on the heated portion of said chutes, means for withdrawing volatilized substances free from products of combustion,v an oxidation chamber underlying the combustion chamber' andv surrounding an intermediate portion of said vertical chutes, means for isolating said oxidation chamber from the combustion chamber, means for admitting .air into theoxida.tion chamber to cause an air current flowing in a direction opposite to the flow of the' material, means for controlling said flow of air, means for withdrawing the products of oxidation without substantially contaminating the `volatilized substances, and means for cooling the lower portion of said chutes to cool the revivi- 'ed material before discharging.l

CARL G. KOEPPL.l

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