US2314112A - Method of coking petroleum residues or the like - Google Patents

Description

March 16, 1943. 2,314,112

METHOD OF GOKIG PETROLUM RESIDUES 0R THE LIKE M. H'. TUTTLE `Filed May 2 2, 1941 2 Sheets-Sheet 1 INVENTOR Un/on l abends ATTORNEY March 16,1943.

AM. H. TUTTLE METHOD 0F COKING PETROLEUM RESIDUES OR THE LIKE Filed may 22, 1941 2 sheets-sheet 2 MSM..

Parental Mar. 1s, 194s UNITED STATES PATENT OFFICE.

METH-OD F COKING PETROLEUM RESIDUES 0R THELIKE Malcolm n. Tuttle, New Rochelle, N. Y., assignmto Max B. Miller & Co., Inc., New York, N. Y., a corporation of Delaware Application May 22, 1941, Serial No. 394,658

' 11 claims. (cl. 2oz-14) This is a troublesome and expensive operation.y

If the cracking is not continued to the end-point, an uncracked residuum, commonly referred to as pressure tar, is left as a waste product.

It has heretofore been proposed to coke tarry materials by spraying them onto a stationary bed of coke heated from below. This process has the disadvantage, among others, that the coking operations must be interrupted from time to time in order to remove the coke from the oor of the still.

It has also been proposed to preheat the coke and feed it through a zone where petroleum is sprayed onto it. Some of the proposals to this effect are unfeasible because the mass becomes .gummy and sticks tothe apparatus; others are impractical because the apparatus is expensive to build and inefficient in operation.

The present invention provides a novel method of separating petroleum residue or the like into volatile constituentsand coke while avoiding the aforementioned disadvantages. According to my invention, a bed of hot granular material is rabbled and the petroleum residue is fed onto the surface of the loose, rabbled material. In the preferred mode of practising my invention, the bed is rabbled to a depth greater than thedepth to which wet petroleum penetrates and the wet tar on each portion of the bed is permitted to become substantially dry or ,non-sticky before -that portion of the bed is again rabbled. The

tar is thus always deposited on hot loose material and is coked before any wet tar reaches the bottom of the bed; and the particles of the material on which the tar is deposited are prevented from sticking to each other or to the walls and other parts of the apparatus; My invention enables continuously feeding the petroleum residue and continuously withdrawing loose coke-coated material. Petroleum residues can thus be converted into vapors and coke or gases without leaving a hard crust on the apparatus.

According to one form of my invention the granular material is preheated and is then dropped into a coking chamber.' The coking takes place by transfer of the heat from the granular material to the petroleum residue or the like. However, my present invention can be practiced in connection with other coking methods which involve diierent ways of supplying heat to ma.- terlal to be coked. Although such other methods are illustrated in Figs. 2, 3 and 4 of the ac- 'companying drawings with a view to indicating certain applications of the invention claimed herein, they involve separate and distinct inventions claimed in my copending applications, Serial `No. 396,020, nled May 31, 1941, and serial No.

401,701, filed July 10, 1940, to which reference is made for further details.

Other features, objects and advantages of the invention will in` part be pointed out andv in part become apparent in connection with the following detailed description of methods according to the invention, references being had to the accompanying drawings wherein:

Fig. 1 is a vertical section through one form of apparatus suitable for carrying out the method according to the invention; and

Figs. 2, 3 and 4 are similar views through other forms of apparatus in which the present invention can be practised.

In Fig.V 1 there is shown at I0 a cylindrical still which includes a number of shelves II having openings I2 and I3 disposed alternately near the center and near the outside wall of the still.

In the center there is a rotating housing I4v -for rabbling or raking this material as the arms rotate. The arms I6 are provided with openings or ports I9 in their rear sides. That is to say, the ports I9 are arranged so that they spray the tar in back of theteeth 20 and onto portions of the bed which has just been rabbled. Inthis way. all the petroleum residue strikes freshly rahbled portions of the bed. The speed of rotation of the arms I6 and the rate of feed of the petroleum residue are adjusted so that the latter becomes substantially dry before the surface is again rabbled. Moreover, the thickness ,of the:y bed is such that the tar is separated linto vapors and coke before wet tar reaches the bottom of the bed.` If desired. the arms I8 could be held stationary and the shelves Il could be rotated.-

Preheated granular material 2l is fed onto the top shelf through an opening 25. It is gradually advanced onto the. next shelf under the action of the rabble arms. The granular material is fed into the apparatus at a temperature above the coking'ltemperature, for instanceat about 1000 to 14Q0 lF. The-petroleum residue to` be coked `is fed continuously through the tubular arms l 8. When the petroleum residue strikes the granular materiaLat such temperature heat is transferred to it and it is converted into vapors and coke. I prefer to control the rate of intro ranged to suit particular rates offeed, but the rabbling teeth should penetrate the bed to such an extent that the raking action prevents agglomeration of the particles. It will be appreciated that the depth of the bed of granular material yof each of the shelves, the number of shelves employed, and the rates of feed of the petroleum residue and granular material can be 'I'he products of combustion escape around baille 55 through a stack 55. A bed of granular coke 51 is maintained in the bottom of the retort. Additional coke may be fed through the opening 58 as desired. A rotating rabble arm 58 is provided with ngers 88 and with openings 5I for the purposes described in connection with Fig. l. Petroleum to be coked is fed through line 52 to the arm 58 which-is driven through a shaft 5I, a pulley 10 and a belt 1i. The vapors produced are withdrawn through a pipe 12 `and the coke produced is withdrawn through the inclined passage 18.

In Fig. 3 there is shown a somewhat less advantageous application of my present invention.

` In this form the coking is conducted in a chamreadily controlled to make the best use of the available heat according to heat-balance calculations.

The granular material covered with coke formed in the apparatus is continuously discharged along the inclined passage 25. The hydrocarbon vapors 'formed are withdrawn through a pipe 38 into a condenser 88. and thence into a receiver 40.

The granular material which is used in accordance with the invention may be an incombustible substance such as ground bauxite or it may be coke or carbon. It will be understood, however, that other granular materials may be employed in place. of those specifically mentioned. It is preferable to employ a substance which is somewhat absorbent and which is not melted by the heat employed in the process. I have found that when using bauxite as the granular material, the particles coated with coke are readily discharged from the apparatus even though they contain as much as 28% by weight of uncoked tarry material which can be extracted from the product by solvents for petroleum such as naphtha. However, the process can be run to the end-point so that the coke produced issubstantially free from such extractableconstituents. When coke is used as the granular material the product may thus consist of practically pure carbon which is adapted for use as metallurgical coke.

When the term granular material" is used herein, it means hard grains but does not mean that these grains-must be very small. Ordinary pea sized particles work very well, but particles -ber 15, the heat being supplied to the bed of 'of the apparatus instead of down through the bottom. Passages 58, 12 and 18 are provided for the same purposes as mentioned in connection with Fig. 2. l

In Fig. 4 there is shown diagrammatically another iorm of apparatus in which my present invention may be used. This apparatus includes a metal shell in which there is a chamber 8i which is heat-insulated by a refractory lining 82 and an asbestos outer jacket 88. A deep bed of granular coke 84 is maintained in the chamber 8i. Air for supporting combustion in the bottom of the coke bed is introduced through a pipe 85. A valve 85 is provided for withdrawing coke or non-combustible material. A rotating rabble arm 81 on shaft 88 is constructed the same and operates the same as described in connection with Figs. l, 2 and 3. The petroleum is coked by the heat which rises through the upper portions of the bed 84. A passage 88 leads into the chamber 8l above the rabble arm for withdrawing the vapors produced. If desired, a screw conveyor 90 may be provided for withdrawing coke. formed by the petroleum which is fed into the top of the bed of coke.

In accordance with the invention petroleum residues or tars canbe heated and distilled so that they are completely converted into vapors and coke. This-is feasible even when the material treated is a low grade pressure tar. The granular material on which the coke is deposited, even though the coke contains substantial amounts of constituents which can be extracted from the coke by solvents, is in such condition..

when produced according to the invention, that it is readily discharged from the furnace without tending to stick to the hearths or walls thereof. These coke-coated particles thus produced are well adapted to be burned for reuse in the coking operation.

The present invention has been described in` connection with the treatment of petroleum residues, but it may be applied to the coking of other tarry materials such as, for example, coal tars, Apressure tars, tars from the Duo Sol or other solvent extraction processes, and the like, which are adapted to be separated or ,decomposed by heat into coke and vapors. Indeed, it is particularly adapted for treating low grade tars whatever their source. If these materials are highly y viscous or normally solid they may be preheated to suitable temperature below the coking temperature, for instance. to about 700-800 F. For

simplicity, the term tar" as used in the claims includes such materials whether obtained from A petroleum or from other sources.

and permitting each application of tar to coketo substantial dryness before again rabbling the bed. Y

2. Method of coking tar which comprises intermittently feeding tar to a bed of hot granular material so -that it doesnot penetrate, to the bottom of the bed and rabbling the upper portion of the bed to the depth to which the tar penetrates, and permitting each application of tar to coke to substantial dryness before again rabbling the bed.

3. Method of coking tar which comprises maintaining a bed of hot granular material, feeding tar to certain portions of the bed while rabbling the other portions, feeding tar to other portions of the bed while rabbling the first-named portions and permitting the tar applied to each portion of the bed to coke to substantial dryness before thereafter rabbling that portion of the bed.

4. The method as claimed in claim 3 wherein tar is continuously fed to the bed and coke and vapors are continuously withdrawn.

5. The method as claimed in claim 3 wherein the bed is circular and the tar is distributed along a continually rotating radius.

6. Method of coking tar which comprises continually feeding granular material onto a supporting surface, continual application of tar to said material at certain timed intervals measured with respect to the rate of tar carbonization, continually rabbling portions of said material during intervals when the tar on said portions of the material is non-sticky, and continually removing the coke and .vapors formed.

7. Method of coking tar, which comprises maintaining a bed of hot granular material of suliicient depth to separate the tar into vapors and coke before wet tar reaches the bottom of the bed, rabbling the bed to a depth as great as that to which tar penetrates into the bed, distributing tar onto the surface of the rabbled bed, and permitting the tar to become substantially dry before again rabbling the surface.

8.v Method of coking tar, which comprises maintaining a uniform bed of preheated granular material which is sufliciently hot and suilciently deep to separate tar into vapors and coke before` wet tar reaches the bottom of the bed, rabbling the upper portion of the bed, continuously distributing iiuid tar onto non-sticky, rabbled portions ofthe surface ofsaid bed, and allowing time for the tar to separate into vapors and coke before again rabbling that portion of the surface of the bed to which tar has been applied.

9. Method of coking tarvwhich comprises distributing tar onto a hot, freshly rabbled, quiescent bed of granular material, permitting the tar to decompose to a point where it is non-sticky, and then rabbling the granular material on which the tar has been coked before again feeding tar .to this portion of thebed.

10. Method of coking tar which comprises distributing tar onto a portion of the surface of a bed of hot granular material, permitting the tar to becomev converted to coke and vapors, thereafter moving some particles in said portion of the bed with respect to other particles to prevent bonding between particles, and thereafter distributing more tar onto the same portion of the surface of the bed.

11. The method of coking tar which comprises preheating granular material, feeding the preheated granular material onto a bed of said material on a stationary support, feeding tar onto the surface of the bed, allowing the tar to coke, thereafter rabbling the bed, and continuously withdrawing coke-coated granular material and vapors.

MALCOLM H. TUITLE.

- CERTIFICATE oF'conEcTIoN. Patent No. 2511;,112. Merch 16, 19115'.

HALCOLH H. TUTTLE.

It 1s hereby certified that error -appears 1n tl;1e pr1nted specification of the above numbered patent requiring `correction es follows Page 1, second column, 11m 15, for 'July 10,' 15h02' read -Ju1y 1o, 19m-L; en d that the said Lettera-Patet should be r'ead with this correction therein that the slame may conform to the record of the case 1n the Patent Office.

signed and and this 13th any er nay, A. D. 19215.

l Henry Van Arsdale, (Seal) Acting commissioner of Patents.

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