US1843570A - Method for distilling oil - Google Patents

Description

Fell 2, 1932- E. W. I UsTER METHOD FOR DISTILLING OIL Filed NOV. lO, 1927 @WS NW www Patented Feb. 2, 1932 S'E'TES FFEE ERIC W. LUSTER, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO STANDARD OIL DEVELOP- MENT COMPANY, A CORPORATION' OF DELAXVABE METHOD FOR DISTILLING OIL Application filed November 10, 1927.

This invention relates to improvements in the distillation of hydrocarbon oil. More particularly, it comprises distilling the lighter components of the oil by bringing it into contact with a fraction of the oil previously segregated and heated to high temperature.

The invention will be fully understood 1from the following description read in connection with the accompanying drawing, in which the ligure is a diagrammatic vertical section of preferred equipment for practicing my method.

In the drawing, numeral 1 denotes a pipe still arranged in a furnace setting 2. The pipe still discharges through line 3 into an intermediate portion of a flash tower 4 containing liquid-vapor contact plates 5 of any suitable kind. The oil emerging from line 3 expands or dashes into the tower.

Vapors from tower 4 pass through line 6 to condensers 7 and 8 connected in series. Uncondensed vapors are conveyed by a line 9 to the lower portion ot' a fractionating tower 10, which contains plates 11. A partial condenser 12 is installed at the top of tower 10 and receives vapors therefrom through line 13. The vapors of the desired product leave condenser 12 through a line 14 and are condensed in the coils 15 of linal condenser 16. From these coils the product is withdrawn through line 17 and collected.

Residual oil in the tower 10 is removed through line 18 to a cooler 19 from which it passes through line 2() to storage. Reflux from partial condenser 12 is returned to tower 10 through line 12a.

The oil to be distilled is supplied through a line 21 by a pump 22 to a preheating coil 23 in partial condenser 12. Thence the oil flows for further preheating through a line 24 to a heat exchanger 25, which receives the hot liquid oil discharged. from flash tower 4 through a line 26. This unvaporized oil leaves heat exchanger 25 through a line 27 connected with a cooler 28, from which it is withdrawn through a line 29. The oil preheated in exchanger 25 Hows through a line 30 to coils 31 andV 32 in ccndensers 8 and 7, wherein the oil obtains additional preheat. it is then discharged through a line 33 into an Serial No. 232,216.

upper portion of ash tower 4 for direct coni I tact with the hot oil entering this tower through line 3 from pipe still 1. y

Condensate formed in the condensers 7 and 8 is withdrawn through a line 34 to the accumulator 35 for hot oil, from which it is forwarded through a line 36 by a pump 37 to the inlet end of pipe still'l. A condensate draw-oft line 37 is connected to line 34 and leads to a cooler 38. Valves 125, 18a, 21a, 26a, 34a, .345, 36a, and 37al are provided respectively in lines 12a, 18, 21, 26, 34, 36, and 37 for the proper control of the system.

The followingv operation for obtaining naphtha and kerosene distillates from a crude oil is described as illustrative of my invention: A crude oil is pumped via line 21, coil 23v line 24, heat exchanger 25 coils 31 and 32 and line 33 into flash tower 4. The operation is so controlled that the temperature at the outlet line 13 is about 300 F., crude oil to the heat exchanger 25 about 170 F., and to the coil 31 about 36001?, so that the oil enters flash tower 4.at about 460 F.

Condensers 7 and 8 are ordinarily regulated to condense light gas oil in amount about equal to one-third the volume ot oil supplied through line 21. This gas oil is drawn off through line 34 to accumulator 35 and is pumped to the pipe still 1, which it should enter at about 450O F. Any excess condensate from condensers 7 and 8 may be taken off through. line 37.

In the pipe still the oil is' heated to about 750o F. for discharge at that temperature into flash tower 4. The heat supplied in this way is suiiicient to vaporize all the lighter constituents of the preheated crude oil, and these constituents pass through-vapor line 6 for selective condensation in condensers 7 and 8, fractionating tower 10, and partial condenser 12'. Nanhtha is taken off from final condenser 16 and kerosene from cooler 19. rihe bottoms emerging from cooler 28 may be sold forfuel oil, redist-illed, cracked, or otherwise used.

Tn starting the operation, accumulator 35 is charged wth gas oil suticient to supply the pipe still until an adequate amount isA produced by condensation in condensers 7 and 8.

The system may be advantageously operated without the use of any other cooling lmedium than the oil to be distilled, but additional heating or cooling media may be supplied if desired. The pressure imposed is only sufficient to force the liquid oil through the pipes. The oil flows rapidly through the pipe still l and no substantial cracking takes place in it or 4elsewhere in the system. My invention is to be differentiatedfrom those methods in which oil is cracked at high pressure and temperature and the cracked product is expanded at reduced pressure into contact with crude oil entering the system. Such methods result in a mixture of natural naphtha and cracked naphtha. rlhe persent method makes it possible to obtain natural naphtha alone, while avoiding all danger of overheating the crude oil. It also keeps the crude oil out of the pipe still and instead uses a middle cut which will be relatively free of corrosive agents even though the crude itself be of a corrosive nature.V

Various changes and alternative procedures and arrangements may be made within the scope of the appended claim, in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art permits.

I claim:

Method of distilling a feed oil containing natural naphtha to obtain the same substantially free from cracked products, comprisV ing passing a middle fraction of the oil through a coil under such conditions of temperature and rapid flow as to prevent substantial cracking and under pressure not materially above that required to force the oil through the coil, discharging the hot oil into direct distillation contact with the feed oil being continuously passed into the contact zonef1 whereby substantially uncontaminated natural naphtha and other lower boiling fractions including said middle fraction are vaporized, removing unvaporized oil, condensing vapors forming said middle fraction7 forwarding a portion of the condensate thus formed to the coil without admiXturc with fresh feed oil, withdrawing a portion of said condensate from the system, taking off vapors escaping condensation and fractionating the same in a Zone separate from that in which distillation of the feed oil takes place.

ERIC W. LUSTER.

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