US2000687A - Continuous pressure distillation process - Google Patents

Description

May 7, 1935. I

o. c. BREWSTER ET AL CONTI IiNUOUS PRESSURE DISTiLLATION PROCESS or inal Filed Feb. 13, 1928 Patented May 7, 1935 PATENT OFFICE CONTINUOUS PRESSURE DISTILLATION PROCESS Oswald C. Brewster, Kansas City, Mo., and Max G. Paulus and Andrew E. Thompson, Casper, Wyo., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana.

Original application February 13, 1928, Serial No. 253,976. Divided and this application July 21, 1930, Serial No. 469,500

14 Claims.

The present invention relates to improvements in the art of pressure distillation of hydrocarbon oils heavier than gasoline for the production of hydrocarbons of the gasoline range boiling points therefrom.. It will be fully understood from the following description illustrated by the accompanying drawing, in which:

The figure illustrates, partly in section and in part diagrammatically, apparatus suitable for carrying out the invention.

This application forms a division of our application, Serial No. 253,976, filed February 13, 1928 for Continuous pressure distillation process.

Referring to the drawing, the numeral 55 indicates a shell or still, 56 the furnace setting, 51 the inclined heating tubes, 58 the lower header and 59 the upper header.

The lower header 58-communicates with the vertical pipe 60 which extends upwardly into the shell 55 and is closed off from the body of the shell by the closure 6| operated by the rod 62. The upper header 59 is connected by the vertical pipe 63 with an enlargedpipe section 64 within the still, open at the top and surmounted by a bell or hood 65 which directs any material issuing from the pipe section 64- in a downward and lateral direction in the shell. The pipe member 64 is connected by a conduit or pipe section 66 with the descending pipe 88. Vapors from the shell or still 55 pass out through the vaporline 61 into the reflux column or dephlegmator 68 in which the portions heavier than the desired distillate products are condensed by cooling. The reflux condensate formed is returned through the line 61 in countercurrent to the vapors issuing from the still, the reflux condensate dropping into a funnel-shaped opening 69 of a pipe 69, by which it is led to the interior of the enlarged pipe section 64.

Connected to the bottom wall of the shell 55, a conduit 28 provided with a pressure release valve 2| and control valves 22, leads to a conduit 23, preferably formed with gradually expanding portions and opening into a reduced pressure drum or chamber 24. Within the drum 24, the conduit 23 opens downwardly above a deflector 25 some distance from the bottom of the drum. In the upper portion of the drum there are provided a plurality of baflle'plates 26 of any suitable form, or other suitable means for preventing entrainment of unvaporized liquids by the vapors leaving the drum. From the upper portion of the drum, the vapor conduit 21 leads vapors to the lower portion of a column or tower 28, illustrated diagrammatically as a bubble tower. The

plates in the tower 28 may be of any desired form.

At a suitableintermediate point in the tower 28, the feed pipe 29 enters and may be employed for the supply of a hydrocarbon oil cooling'medium or for the supply of fresh oil fed to the unit. A second supply pipe 30 enters the upper portion of the tower and may be employed for supplying thereto a cooling medium of a lower range of boil-' ing points, such as,.for example, a condensate from the vapors evolved from the tower 28. From the upper portion of the tower, a vapor conduit 3| leads to any suitable condensing means (not shown).

Condensate formed in the fractionating column or tower 28 and collected in the base thereof is together with the fresh feed withdrawn through valved pipe 32 and forced by pump 33 through the valved pipe 34 directly to a downwardly directed nozzle 35 in conduit 60.

From the base of the drum 24, unvaporized oil is discharged through the valved pipe 36 and forced by pump 31 through the pipe 38. The latter communicates with a pipe 39 provided with control valve 40 leading to a tar cooler or heat exchanger 4|, from which the cooled unvaporized oil or tar is discharged through the line 42. The pipe 38 also communicates with a line 43 provided with control valve 44 through which any desired portion of the unvaporized oil or the tar may be directed to the interior of the shell 5.

Incarrying out an operation in accordance with the present invention, the still is initially charged with oil at a level substantially above the tops of the pipes Eli-and 64, said pipes, the headers 58 and 59 and the inclined tubes 51 being entirely filled. With a still of ordinary dimensions, say 30 feetin length and 30 feet in diameter, a suitable initial charge is 12,000 to 13,000 gallons. The rod 62 is operated to open the upper, end of the pipe 60 so that the entire contents of the still may be circulated and brought up to cracking temperature by the furnace heat applied 'to the inclined tubes 51. The stock initially charged into the still may suitably be of the gas oil type and have a gravity of say 30 to 33 A. P. I.

After the contents of the shell have been brought to cracking temperature, for example, 725 to 750 F., a suitable superatmospheric pressure being maintained thereon, the valve 2| is opened to permit the flow under reduced pressure of a certain proportion of the contents oi. the still through the pipe 20 and conduit 23 leading into the drum 24. In the drum 24 a separation of vapors from unvaporized oil takes place, the vapors passing through conduit 21 into the 'say, 735 F. reached, a certain proportion oi. the tar or .bot-

column 28. In order to effect a partial cooling of the vapors in the column 28, oil such as the stock which it is desired to feed into the unit during operation, is fed in through the pipe 29 and is itself in part preheated by the vapors passing through the column. This feed may be suitably a gas oil of characteristics similar to that charged into the still, although, as hereinafter pointed out, the cold stock fed into the unit in this manner may be of widely varying characteristics, crude oil, for example, being suitable. The unvaporized portion of the feed, preheated by the vapors in the column 28, together with the condensate formed from such vapors, is withdrawn through the pipe 32 and forced by the pump 33 through the conduit 34 into the nozzle 35 from which it is discharged into the depending pipe, 60, which is then cut oif from communication with the contents of the still by seating the closure member 5|. In the initial stages of the operation, after .discharge of liquid products has begun from the shell 55, the entire quantity of tar or unvaporized oil from the lower portion of the drum 24, discharged through the pipe 36, may be forced by the pump 31 through the line 43 back into the shell. During this portion of the operation, it will be noted that the entire unvaporized portion of the liquid removed from the still remaining in the drum 24 is returned directly to the shell or still and the condensate from the vapors given of! from the drum 24 is returned together with the fresh feed stock or the unvaporized portion thereof to the interior of the pipe 50, to pass through the heating tubes 51 and the ascending pipe 53 into the vertical pipe 64 or the horizontal pipe 66. Also, the reflux condensate formed in the column 68, being the portion of the vapors evolved from the still heavier than the desired distillate product, is returned through the pipe 51 and conduits 69 and 69 directly to the enlarged pipe section 64 within the still. The pipe 88 permits the recirculation of a portion of the material which has already passed through the heating pipes 51.

The operation in'the manner described is continued until the contents of the shell or still 55 have reached the conditions which it is desired to maintain throughout the operation. For example, with an initial charge of a type of gas oil having a gravity of 33 A. P. 1., the stock in the shell may reach an operating temperature, of, After this desired point has been toms remaining unvaporized in the drum 24 may be discharged through the valved pipe 39 and the tar cooler or heat exchanger 4|, the amount so discharged being controlled to maintain the liquid in the still 55 of the desired character. The amount of fresh feed stock added to the system through the supply pipe 29 is controlled to maintain a substantially constant volume of oil intogether with the tars or bottoms discharged through line 39.

By operating in the manner described, we have been able to run continuously for long periods of time andwith great economy of operation.

Furthermore, in operating in accordance with the present invention, the desired heating. of the oil is eflected without the use of excessively long nre'd coils involving great friction losses and p ssure drops and without the involvedand expensive pumping arrangements that are ordinarily re- I quired in connection therewith.

It is readily apparent that the operation may be modified in many respects within the scope of the present invention. Thus the quantity and character of the unvaporized liquid or tar formed in and withdrawn from the flash drum 24 may be controlled by varying the extent of vaporization taking place therein, any such variation producing a. corresponding result in the character of stock in the shell or still. If desired, steam or other vapor may be introduced in the body of liquid therein or into the stream of liquid entering the drum. As shown in the drawing, suitable means are provided for using the vapor product present in the still for this purpose. Thus vapors from the still may pass through line 15 controlled by valve 16 directly to the tar line 20 through which the liquid from the still passes to drum 24. A similar result may be secured by increasing the difference in pressure between the still and the drum 24, as by raising the pressure,

in the former.

It is apparent that if increased proportions of the liquid withdrawn from the still are vaporized in drum 24, larger amounts of condensate are formed in tower 28 and returned to the system, thus permitting the elimination of a greater proportion or of all of the tar or residuum formed in drum 24.

We claim:

1. In apparatus for distilling hydrocarbon oils under pressure for the production of lighter hydrocarbon oils of the character of gasoline, a container, a plurality of inclined pipes below said container, headers at each end of said pipes, con

duits connecting said headers with the interior of carbon oils of the character of gasoline, a container, a plurality of inclined pipes below said container, headers at each end of said pipes, conduits connecting said headers with the interior of the container, said conduits extending above the bottom of said container, a closure member for closing the top of the conduit extending from the lowermost header into the container, 9. bell surmounting the top of the conduit entering the container from the uppermost header, and a connecting conduit within the container extending between the conduits from the headers.

3. In apparatus for distilling hydrocarbon oils under pressure for theproduction of lower hydrocarbon oils of the character of gasoline, a container, a plurality of inclined pipes below said container, headers at each end of said pipes, conduits connecting said headers.with the interior 'of the container, said conduits extending above the bottom of said container, a closure member for closing the top of the conduit extending from the lowermost header into the container, a bell surmounting the top of the conduit entering the container from the uppermost header, a connecting conduit within the container extending 'between the conduits from the headers, means for withdrawing vapors from the container and cooling said vapors, thereby condensing heavier hydrocarbons therefrom, and a conduit for conducting such condensed heavier hydrocarbons into the conduit extending from the uppermost tube header into the container.

4. In apparatus for distilling hydrocarbon oils under pressure for the production of lighter hydrocarbon oils of the character of gasoline, a container, a heating section, a conduit for conveying oil from the container through the heating section and a second conduit for returning said oil from said zone back to the container, a tubular conduit within said container interconnected and communicating with said first-and second-mentioned conduits, and closure means for cutting 01f communication between the container and the inlet to said first-mentioned conduit.

5. In apparatus for distilling hydrocarbon oils under pressure for the production of lighter hydrocarbon oils of the character of gasoline, a container,. a heating section, a conduit for conveying oil from the container through the heat ing section and a second conduit for conveying said oil from said zone back to the container, a tubular conduit within said container interconnected and communicating with said first-and second-mentioned conduits, closure means for cutting off communication between the container and the inlet to said first-mentioned conduit, means for withdrawing vapors from the container and condensing portions thereof heavier than the desired gasoline product, and means for introducing the resulting. condensate into the first-mentioned conduit below said closure means.

6; In apparatus for distilling hydrocarbon oils under pressure for the production of lighter hydrocarbon oils of the character of gasoline, a container, a heating section, a conduit extending through said heating section, separate conduits connecting each end of said first mentioned conduit with the interior of said container at sepparately spaced points thereof, said second mentioned conduits extending above the bottom of said container, and a tubular conduit within the container and interconnecting said second mentioned conduits extending above'the bottom of the container, one of said conduits being provided with a constricted opening within said chamber and through which a portion of the heated oil from said conduit in the heating section may escape into the interior of said container.

7. In apparatus for distilling hydrocarbon oils under pressure, a container adapted to contain a body of oil, means for maintaining the body of oil in said container at conversion temperature and under pressure, means for withdrawing vapors from said container and condensing said vapors, a discharge pipe for the removal of unvaporized liquid from the container, a pressurerelease valve in said discharge pipe, an enlarged chamber into which said discharge pipe opens, an inlet pipe and an outlet pipe communicating with said container, a heated conduit interconnecting said inlet and outlet pipes outside said chamber, a tubular conduit within said container connecting said inlet pipe to said outlet pipe, separate means for introducing vapors from said container directly into said discharge pipe between the pressure-release valve and the enlarged chamber, and means for cuttingofi communication between said container and said outlet pipe.

8. In apparatus for distillin'ghydroc'arbon oils under pressure 'for the production of lighter hydrocarbon oils of the character of gasoline, a container, a heating section, a conduit comprising a portion extending into and through said container and another portion extending through said heating section and connected to the first a constricted opening through which a portion of the oil may escape into said container and means for supplying fresh oil to said conduit.

9. The method of eifecting the distillation of hydrocarbon oils under pressure for the production of low boiling hydrocarbon products such as gasoline which comprises maintaining a substantial body of liquid oil at conversion temperature and under pressure, flowing additional liquid oil to be converted continuously through a heating zone and heating it during its fiow therethrough to conversion temperature, thereafter bringing said additional liquid oil into indirect heat conductive relationship with said body of oil and returning a portion of the said additional 'oil to pass again through said heating zone without coming in direct contact with said body of liquid oil, discharging another portion of the additiorral liquid oil after passing through the heating zone into said bodyof liquidoil to admix therewith for the first time and supplying fresh liquid oil to the remaining portion of oil entering the heating zone.

10. The method of effecting the distillation of hydrocarbon oils under pressurefor the production of low boiling hydrocarbon products such as gasoline which comprises maintaining a substantial body of liquid oil at conversion temperature and under pressure, flowing liquid oil to be converted continuously through a heating zone and heating it during its fiowtherethrough to conversion temperature, bringing said liquid oil into indirect heat conductive relationship with said body of oil and thereafter'returning a portion of the said liquid oil to pass again through said heating zone, discharging another portion of the liquid oil after passing through the heating zone into said body of liquid oil to admix therewith for the first time and supplying fresh oil to the remaining portion of oil entering the heating zone and withdrawing liquid ioil continuously from the body of oil, vaporizing a portion of the withdrawn liquid and returning unvaporized portions thereof to the said body of liquid oil.

11. The method of effecting the distillation of hydrocarbon oils under pressure for the production of low boiling hydrocarbon products such as gasoline which comprises maintaining a substantial body of liquid oil at" conversion temperature and under pressure, flowing additional liquid oil to be converted continuously through a heating zone and heating it during its flow therethrough to conversion temperature, bringing said additional liquid oil into indirect heat conductive relationship with said body of liquid oil and returning a portion of the said additional liquid oil to pass again through said heating zone, discharging another portion of the said additional liquid oil after passing through the heating zone into said body of liquid oil to admix therewith for the first time and supplying fresh oil to the remaining portion of oil entering the heating zone and withdrawing liquid continuously from the body of oil,

without admixture therewith thence to said heating zone.-

' 13. The methbdoi eflectingthe distillation of hydrocarbon oils under pressure for the production of lower boiling products which comprises maintaining a body of oil at conversion temperature, continuously cyclically circulating an independent body 01 oil through a heating zone and thence through an elongated tubular passageway in indirect heat exchange relation with said firstnamed oil body and back through said heating zone whereby said oil is heated to conversion temperature without coming in direct contact with said first mentioned body of oil, discharg-- ing predetermined portions of said cyclically circulating oilinto said first-named oil body and introducing additional oil into said second-named circulating oil body. j

14. The method of eifecting the distillation of hydrocarbon oils under pressure for the production of low boiling hydrocarbon products such as gasoline, which comprises maintaining a body of oil under pressure, circulating oil from said body.

of oil in a confined stream through a heating zone and back to said body of oil to raise the oil body to conversion temperature, separately withdrawing evolved vapors from said oil body and fractionallv condensing them to separate as reflux condensate undesired higher boiling products of said vapors, stopping said circulation of unvaporized oil from said body and collecting reflux condensate derived from said tractionally condensing operation in a separately maintained body relative to the aforesaid oil body, circulating condensate from said separately maintained body in a confined stream through said heating zone and directly back to said separate body to raise said condensate to conversion temperature, and-substantially continuously discharging a portion of said maintained body of condensate into said first namedoil body. I

' OSWALD c. BREWSTER.

MAX G. mums.

ANDREW E. THOMPSON.

' QERTIFI-CATE or connect on Patent-No. 2,000,681, r May 7,' 19s s..

, i OSWALD C.'BREWSTER.EIAL.IY

It is hereby certified thsterror appears in the printed specification ef. the

above numbered patent requiring correction as follows: Pagel3, first column, line 46, clnim 6', strike ou'rithe'eomma and words one of said conduits" and insert the same before "extending'" in line 45; and thatYsaid LettersPat'ent should be read with this 'cor'rection therein {hat the same may confprm to the record of the case in the Patent Office. r Y

- Signed and sealed this 2nd day of July, A; D. 1935.

I Leslie Fraz er (Seal) I Acting Commissioner of Pa tents

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