US1348268A - Apparatus for cracking hydrocarbons - Google Patents

Description

J. W. COAST, JR. APPARATUS FOR CRACKING HYDROCARBONS.

APPLICATION FILED APR. 16, 1917. RENEWED JUNE 14, 1920.

1,348,268, Patented Aug. 3,1920.

2 SHEETSSHEET I.

L W. COAST, JR.

APPARATUS FOR CRACKING HYDROCARBONS.

APPLICATION FILED APR. 16. 1917. RENEWED JUNE 14, 1920.

1,348 268 Patented Aug. 3, 1920.

2 SHEETSSHEET 2.

(XV (draw;

UNITED STATES PATENT OFFICE.

JOHN W. COAST, JR., OF TULSA, OKLAHOMA, ASSIGNOR TO THE PROCESS COMPANY, A CORPORATION OF MARYLAND.

APPARATUS FOR CRACKING HYDROGARBONS,

Specification 01' Letters Patent.

Patented Aug. 3, 1920.

Application filed April 16, 1917, Serial No. 162,384. Renewed June14, 1920. Serial No. 889,010.

To all whom it may concern Be it known that I, JOHN V. COAST, Jr., a citizen of the United States of America, a resident of Tulsa, in the county of Tulsa, State of Oklahoma, have invented certain .new and useful Improvements in Apparatus for Cracking Hydrocarbons, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to lmpr'ovementsin apparatus for cracking high boiling point petroleum hydrocarbons. In cracking hydrocarbons of this kind to obtain cracked gasolene it has been found necessary to condense the unconverted, or partially converted, high boiling fractions before they reach the condenser from which the low b011- ing point product is recovered. In actual practice, the vapor is usually conducted away from the still and then through one or more reflux condensers whereby the high boiling fractions are condensed, the condensate being conducted from the reflux condensers to the still for further treatment.

The main object of this invention is to condense the high boiling point fractions 1n the upper portion of the still, perm tting the condensate to drop back into the liquid, and conducting the remaining vapor from the still to the condenser, from which the product is recovered. T o accomplish this, the upper portion of the still 18 maintained in a relatively cool condition, the vapor being deflected and conducted along the cool portion of the still in such a manner that the temperature of all of the vapor is very materially reduced. thereby condensing the high boiling point fractions before the vapor passes from the still. Owing to the peculiar manner in which the vapor is baiiled, deflected, and brought into contact with the cool parts of the still, the temperature of the vapor may be reduced to such a low degree that only the desired low boiling point fractions will escape from the still. In this event, it will be unnecessary to pass the vapor through the ordinary reflux condensers.

In the preferred form of the invention, a relatively cool fluid, preferably a high boiling point hydrocarbon liquid, is introduced into the vapor confined in the still. This liquid serves as a condensing medium for the vapor, and it is eventually vaporized and cracked in the still. The vapor is also, preferably, subjected to the action of relatively cool steam before it escapes from the still.

Figure I is a diagrammatical view of a cracking apparatus constructed in accordance with my invention.

Fig. I1 is an enlarged transverse section taken through the middle portion of the still, showing the baffles and the restricted vapor passageways at the upper portion of the still.

Fig. III is an enlarged longitudinal section of the still.

To illustrate the invention, I have shown a cracking still 1, in the form of a large boiler, arranged above a heating chamber2, and connected by means of a vapor pipe 3 to a water cooled condenser 4 from which the low boiling point product is recovered.

The apparatus shown is particularly adapted for use in cracking high boiling point products of distillation, such, for example, as the distillates or residues resulting from the distillation of crude petroleum. The contents of the stillare, of course, maintained under pressure, and any desired pressure may be obtained by regulating a valve in the vapor pipe 3. The pressure in the still is preferably greater than 50 pounds per square inch, for example, about 80 pounds per square inch, and the temperature of the liquid contents of the still preferably ranges from about 600 F. to about 800 F. The low boiling point vapor, passing from the liquid, flows through the relatively cool upper portion of the still and is discharged into the vapor pipe 3. The relatively high boiling point fractions are condensed in the still, as will be hereinafter described, and permitted to drop back into the liquid. This high boiling point condensate includes some heavy coke-forming fractions commingled with lighter fractions which may be redistilled to form a part of the low boiling point product.

The end portions of 'the still bottom are seated upon the walls 6 of the heating chamber 2. and these walls protect said end por- 'tions from the intense heat of the heating chamber. The heat is transmitted directly through the middle portion of the still bottom. and the protected end portions of said bottom are maintained in a relatively cool condition.

The vapor cooling meansincludes a large vapor passageway 8. End baflle members 9,

located at the'ends of the long'bafile member 7, are separated from the end walls of the still to form restricted passageways 10 or the rising vapor flowing t0 the restricted passageway 8.v The lower edges of the end baffle members 9r'are located slightly above the surface of the liquid in the still to form restricted outlet ports 11 for the vapor flowing to the end passageways 10. f

An air cooled tower 12 extends upwardly from the top wall of the still to receive the I vapor flowing from the long restricted-passageway 8. 13 designates a cylindrical 25 baffle. device arranged in the air cooled tower and separated from the upright wall thereof to provide av restricted annular passageway 14 for the rising-vapor. The cylindrical bafile device 13 is in the form of a receptacle, open at the top to receive the vapor and closed at the bottom to exclude the rising vapor.

To prevent the vapor 7 from escaping around the lower longitudinal edges of the long baffle member 7, these edges are preferably located below the level of the liquid in the still, as shown most clearly in Fig. II. Condensate troughs 15, located adjacent to the longitudinal edges of the baflie member 7, are inclined toward the ends of the still. The condensate, flowing from the baffle member 7, drops into the troughs 15, and the .heavy coke-forming fractions are thereby action "of relatively cool air currents. 55.

conducted to the end portions: of the still, Where they will settle upon the still bottom at points above the walls 6. These heavy fractions drop by gravity, and they accumulate on the protected end portions of the still; bottom, instead of being permitted to collect .at points where the heat is transmitted to the still.

Instead of being protected, the upper portion of the still is subjected to the cooling A jacket"' '16, approximately semi-circular in 1 cross section, is preferably arranged over the correspondingly shaped upper portion of the still to provide an air passageway 17, and air under pressure may be discharged from a pipe 18 to thepassageway 17'for the purpose of'creating a forced draft of cool air over the top wall of the still. A perforated discharge pipe 19, located in the restricted passageway 8. is connected to a supply pipe 20 through which a relatively cool fluid is conducted for the purpose of cooling the vapor. This relatively cool fluid is, preferably, a high boiling point hydrocarbon liquid, and it is discharged through the numerous perforations inthe pipe 19 so as to cool the vapor, at the same time cooling the upper portion of the still. This hydrocarbon liquid, in addition to serving as a cooling medium, is subjected to the cracking process carried on-in the still, and it eventually forms part of the low boiling point product.

A perforated discharge member 22 (Fig. III) arranged in the cylindrical baflie device 13, is connected to a steam pipe 23 provided with a regulating valve24. Relatively cool steam, passing from the dischargemember 22, is forced into the vapor in the cylindrical baflie device 13.

The vapor rising from the liquid under the long bafiie member 7 is trapped by the baffles 9. This vapor passes under the lower edges of the end baffles 9, upwardly through the restricted end passageways 10, through the long restricted passageway 8 above the baflie 7, thence upwardly in the restricted passageway 1 1, downwardly in the cylindrical bafile device 13 and then into the vapor pipe 3. The upper portion of the still is maintained in a relatively cool condition, as previously pointed out, and the vapor is baflled, deflected, brought into contact with the cool parts of the still, andotherwise acted upon in such a manner that the temperature of all of the vapor is greatly reduced. As a consequence, the high boiling point hydrocarbons are condensed in the still, and all of the vapor escaping from the still maybe condensed in the water cooled condenser 4 from which the cracked product is recovered.

The condensate formed in the cylindrical baffle device 13 passes through a liquid seal 8, between the top wall of the still and the bafiie 7, flows downwardly on the top face of the a baflie 7 and commingles with the liquid'in the still. The heavy coke-forming fractions are conducted, by the inclined troughs 15, to the end portions of the still, where they drop by gravity to the protected end portions of the still bottom.

In treating petroleum hydrocarbons to obtain cracked gasolene, the object is to recover all of the vaporized fractions having a normal boiling point lower than about 500 F The fractions having higher boiling points should be continually subjected to the high pressure and high temperature in the still for the purpose of converting them into lighter fractions. By reducing the temperature of the vapor in the still as herein shown and described, all of the vaporized fractions having a normal end or dry point higher than 500 F. may be condensed in the still. All of the vapor passing from the still will then be free from the undesirable heavy fractions, and the desired product may be obtained by condensing all of this vapor in the water cooled condenser 4.

The condensing action at the upper por-.

tion of the still can be varied by regulating the flow of relatively cool steam, air or liquid, each of which serves as a cooling medium for the vapor. It will, therefore, be apparent that the apparatus can be easily adjusted or regulated to condense, or knock back all of the fractions having a boiling point higher than about 500 F.

- I claim 2- 1. A. cracking still having a vapor outlet, and "apor cooling means including a baflle device arranged within the still and extending from a point near one end of the still to a point near the opposite end, said bafile device being located near, and se pa-.

rated from, the top wall of the still to form a restricted passageway for the vapor flowing to said outlet, said baflle device being in the form of an inverted trough, closed at the top and open at the bottom to provide a vapor trap, and the lower edges of said baflle device being located below the liquid level in the still so as to prevent the vapor from flowing around said edges.

2. A cracking still having a vapor outlet, and vapor cooling means including a baflie device arranged within the still and separated from the top wall thereof to form a restricted passageway for the vapor flowing to said outlet, and an end'bafl'le located at an end of said bafile device and separated from an end wall of the still to form arestricted passageway for vapor flowing to the first mentioned passageway, the lower edge of said end battle being located above and adjacent to the li uid level in the still.

3. A cracking still aving a vapor outlot, and vapor cooling means including a battle (lCX'lCG arranged within the still and separated from the top wall thereof to form a restricted passageway for the vapor flowing to said outlet, and end battles located at the ends of said baflle device and separated from the end walls of the still to form restricted passageways for the rising vapor flowing tothe first mentioned passageway, the lower edges of said end bafiies being located above and adjacent to the liquid level in the still.

4. A cracking still having a vapor outlet, and vapor cooling meansincluding a vapor trap in the form of an inverted trough closed at the top and open at the bottomand located within the upper portion of the still and separated from the walls thereof to form restricted passageways for the vapor flowing to said outlet.

5. cracking still having a vapor out let, and vapor cooling means including a vapor tra'p in'the form of an inverted trough closed at the top and open at the bottom and located within the upper portion of the still and extending approximately from one end of the still to the other, said vapor trap being separated from the adjacent walls of the still to form restricted passageways for the vapor flowing to said outlet.

6. A cracking still having a vapor outlet, and vapor cooling means including a battle device arranged within the still and extending from a point near one end of the still to a point near the. opposite end, said bafile device being located near, and separated from, the top wall of the still to form a restricted passageway for the vapor flowing to said outlet, a discharge member arranged within the still between said bafile device and the top of the still, and means for conducting a relatively cool fluid into said discharge member.

7. A cracking still having a vapor outlet, vapor cooling means including a battle device arranged within the still and extending from a point near one end of the still to a point near the opposite end, said baflle device being located near, and separated from. the top wall of the still to form a restricted passageway for the vapor flowing to said outlet, and troughs arranged in the still to receive the condensate flowing from said baflie device.

8; A cracking still having a vapor outlet, vapor cooling means including a bafile device arranged Within the still and ex tending from a point near one end of the still to a point near the opposite end, said bafile device being located near, and separated from, the top wall of the still to form a restricted passageway for the "apor flowing to said outlet, and inclined troughs whereby condensate flowing from said baflie device is conducted to an end portion of the still, said troughs being located adjacent to the lower longitudinal edges of said baflle device.

9. A cracking still having a vapor outlet, and vapor cooling means including a baflie device in the form of an inverted trough arranged within the still and separated from the top wall thereof to form a restricted passageway for the vapor flowing to said outlet, and a cooling tower arranged to receive the vapor flowing from said restricted passageway to said outlet.

In testimony that I claim the foregoing I hereunto aflix my signature.

JOHN W. COAST, JR.

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