US1264435A - Process of distillation and apparatus therefor. - Google Patents

Description

G. L. PRICHARD,

PROCSS 0F DISTILLATION AND APPARATUS THEREFOR. APPLICATION FILED JUNE 28. |916.

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G. L. PRIC'HARD.

' APPLICATION FILED .IUNE 28, I9I6.

PocE-s's of msmLAnoN AND APPARATUS THEREFOR.

. Port Arthur, y I State of Texas, have invented certain new progressively raised in RTI-rua,` TEXAS,

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ASSIGNOR TO GULF REFINING COM- PANY, OF PITTSBURGH, PENNSYLVANIA, A CGRlPORATION 0F TEXAS. n

PROCESS 0F DSTILLATIN ND l' Aros rnnnnroa.

To all wko/1n t may concern Be it known that l, GEORGE L. PRICHARD, a citizen of the United States, residing at in the county of Jefferson and and useful Improvements in AProcesses of Distillation and Apparatus Therefor, of which the following is a specification.

This invention relates to processes of distillation and apparatus therefor; and it comprises a method of obtaining uniform cuts or fractionstroleum naphtha and similar distillates wherein such a distillate is redistilled with the aid of .steam heat in a plurality of successive stills operating in series as regards the material to be distilled, the liquid being submitted to a prolonged and methodical evaporative treatment in each such still and the, vapors from each such still being thoroughly dephlegmated with the aid of inflowing liquid, and the residual oil discharged freed from the oils of the several distillates, and it also comprises an assemblage of apparatus elements useful in the performance of such process and comprising a plurality of steam heated stills arranged for successive treatment of naphtha or the like, each such still being arranged to distil liquid passing in transit therethrough 1n a comparatively long path and each being provided with means for thorough dephlegmatory exchange between the vapors therefrom and the liquid fed thereto; all as more fully hereinafter set forth and as claimed.

In the manufacture of distilled commerI cial products from petroleum, it is customary to take od and condense a product called crude naphtha. This crude naphtha is afterward redistilled with the aid of steam for the preparation of various naphtha products or naphthas of dilferent gravities; which, for lack of better names, may, beginning with the lightest, be called gasolene, naphtha and benzin. In the still remains a comparatively high boiling residual oil which is the equivalent-of the ordinary kerosene distillate. Tn this distillation heat is usually furnished by blowing free steam into the still through perforated pipes arranged near the bottom of the still. Sometimes the heat of steam coils is resorted to fpr distillation (close steam).I The distilla' Wh tlon is ordinarily in a slngle still which is temperature with Specication of Letters Patent.

Application led .Tune 28, 1916.

and products from pe-.

Y fractions or cuts Patented Apr.. 30, ilml. serial no. 106,401.

separate collection of the condensates or cuts coming over at desired temperature intervals. This operation is of course intermittent, and it is diiiicult to secure as uniform products in a single operation as is desirable. Tf the operation be so conducted as to give properly separated distillates the quality of the residual oil (kerosene) suffers and on the other hand if the operation be so conducted as to give a satisfactory residual oil the quality of the distillates is not so good. And in any event the several are not well separated from each other.

ln the present invention I have devised a method and provided an apparatus adapted for making such a separation as that above indicated, obtaining better distilled products in the sense of materials having narrower range of boiling points and being to that extent much more definite than those usually obtained in `redistilling the crude naphtha while also giving a goodquality residual oil (kerosene). For this purpose, instead of using a single still and collecting the various fractions or cuts from it successively, I distil the liquid, so to speak, in transit, using a plurality of stills, each vof which is adapted to furnish a single cut and passing the flowing liquid which supplies this stillin a countercurrent against the vapors coming from such still. The liquid flows through the plurality of stills in succession, the liquid from the first such still being supplied in countercurrent against the vapors coming from the second such still and so on. And T provide the interior of each such still with baffles or similar devices adapted to cause the liquid introduced at one end of the still to travel progressively toward the other end of the still. The undistilled residual oil finally discharged is freed of all oils volatile at the temperatures employed in distillation.

ile T may use any type of steam heated still and arrange these stills in any desired manner, yet I find it better to use a certain particular construction and relation. of the several stills and their settings. .l find that it is desirable to superimpose the several stills in vertical arrangement as this gives convenience in operation and connections. en 'so superimposed, the stills may be supported in any of the ordinary types of setting, but l ind it better to use a special `to the third still.

steel skeleton frame carrying supporting cradles, etc. and a special type of heat insulation for each still (see the application of Herbert Henderson Serial No. 84180, filed March 14, 1916). In so arranging the stills, a steel skeleton frame is employed and the several stills are supported therefrom on cradles while each still is provided with heat insulation in a special manner; being covered with an outer layer of heat insulating material at its top and an inner layer of heat insulation at the bottom. The upper layer of heat insulation may be supported on suitable angle irons projecting from the sides of the still bodies which may be, as usual, horizontal steel cylinders. Ar-

.ranging the insulation in this manner renders detection of leakage, repairs, etc. easily practicable.

I shall hereinafter describe my process and organization of apparatus elements as applied to the manufacture of three differ'- ent cuts from a petroleum product of the nature of the crude naphtha described, it being understood -that I may use two such stills or more than three without departing from the principles of my invention. In such an organization, I mount the three stills-one above the other with the still 0perating at the lowest temperature at the top. Each of the stills communicates with its own tower or dephlegmatory column which may be provided with internal baffles or shelves. For structural convenience, I may mount these three columns in the form of a single column divided by suitable partitions at proper points. The incoming liquid is supplied to the top of the sub-tower connected with. the rst or topmost still and passes downward through this subtower against the vapors passing upward therethrough from the still until the liquid reaches the bottom of the sub-tower whence it is supplied into the still. The residual liquid coming from this first still is similarly supplied to `the sub-tower of the next succeeding still; and from the second still the residual liquid similarly goes High test residual oil thoroughly freed of matters volatile at the temperatures employed, is withdrawn from the last still in the series and cooled in any suitable manner. Although special filmevaporating stills may be employed, I find it desirable to use stills of the Ordinar cylindrical shape but each provided with a plurality of baiiie plates to give a circuitous liquid iow therethrough. Three baiies may be used in each still. The vertical arrangement of the stills with the fresh liquid supplied at the top allows feed through the system to be by gravitation. v

4In the accompanying illustration I have shown, more or lessI diagrammatically, certain embodiments of apparatus elements within the present invention and suitable for the performance of the stated process v In this showing:

Figure 1 is an end elevation, certain parts being in section, and

Fig. 2 is a side elevation, certain elements being in section.

In this apparatus as shown, three steam stills, A, B and C, are shown mounted in superimposed arrangement. As shown, the still having the lowest temperature, A, is uppermost, while that having the highest temperature, C, is lowermost, so that the liquid may flow downward through the system by gravitation. As shown, these stills are mounted on a steel framework 1, provided with suitable cradles 2, supporting members 3, etc. The necessary heat insulation for the stills is provided, in the type of still shown, by an upper outer layer 4 of radial tile or other suitable material supported on angle irons 5. In the interior, at the bottom portion of the still, may be another layer of heat insulating material 6. This arrangement is convenient for a number of reasons.

As shown each still is provided with its own dephlegmating column and these dephlegmating columns for structural reasons are made one continuous structure; the three sections being mounted in superimposed relation as one continuous column. From still A vapors are led outward through vapor line 7 entering at the base of section 8. As shown this column is provided with plates`9 of a usual type. Any other kind of filling and film-forming material or structure may be employed in its lieu. Passing upwardly through the columns past these plates the vapors go to vapor outlet 10, whence they are led to any suitable condenser (not shown). Liquid is introduced into the top of the column at 11 through heat exchanger 12, and may, as shown, pass in countercurrent to and be warmed by the outgoing vapors which pass outward through vapor outlet 10 to any suitable condenser (not shown). The incoming liquid passes downward through the column-seclike and receives vapors from B through vapor line 16. The vapors pass uawardly against downflowing liquid coming rom the previous still A through overfiow line 17. The liquid after passing through this section and being enriched by condensed vapors passes into B through feed line 17 From B residual liquid passes through overflow line 18 to the top of the lowermost section zol , still C.

Within, the stills are generally provided with the usual. steam introduction means 23 and (see Fig. 2) internal bames 24, 25 and 26 adapted to cause a tortuous dow of y"liquid from end to end of the still. As may be seen by Fig. 2, the liquid to be distilled enters at one end of the still and leaves at the other, flowing past the stated baies. rI`he vapors from the second section (15 pass to any suitable condenser (not shownl through vapor outlet 27 and those owermost section (19) through vapor out- From the lowermost or hottest still C the thoroughly exhausted liquid is led to a suitable cooler through outlet 29. 'Ihe hot liquid may be led through heat ,interchanger 29 to heat the oil supplied to the system (through 11). Pipes 3l, 32 and 32 connect stills-A, B and'C, respectively, to a riser 30, leading to a pump (not shown). 'Ihis construction permits the oil to be pumped from the stills for repairs and like purposes. Connections 33, condensed water from A, B and C, respectively into funnel connections 33', 34e and 35 which connect to the sewer line 36. Ihe

connections allow the operator to determinevwhen the water has been `drawn entirely from the still.

In the use of the described` structure, crude naphthais allowed to How in through inlet 11 and is warmed in heat interchangers 29 and 12. It flows downwardly over the plates 9 until it reaches still A through 14.

In so passing it gives up vapors of low boilmg materials to the vapors from 7 and itself condenses higher boiling lportions of such vapors so that the distillate obtained by condensing the vapors from 10 is a uniform gasolene of good quality. In still A the incoming liquid is delivered at one end of the still and passes slowly toward the other end past the baflies and is thoroughly freed' of its low boiling constituents in so passing., At the time it reaches line 17, it has been thoroughlyfreed of the grade of naphtha called gasolene. From 17 it flows down through section 15 against the upwardly passing vapors from B and dephlegmates these vapors in a similar way until it reaches still B through line 17. I-Iere it passes from end to end of the still in a similar manner until it flows outwardly at 18. In so flowing, the second component of the crude naphtha, which may be here called naphtha, furnishes vapors which in going through section 15 are thoroughly dephlegmated giving a `uniform cut in the condenser (not shown). The outiowing liquid from B through 21 into ii vapors from C passing from the `method I have 34 and 35 allow draining od'. b

passed in contact passing through 18 into the lowermost section 19, flows downwardly therethrough against the vapors passing from C and it nally reaches C through` inlet 21. The through 20 and 19 at 28 are condensed to form benzin. flowing through still C the liquid to exit withdrawn at 29 and cooled in any suitabledevice (not shown) is an oil which is equivalent to or is a high grade kerosene distillate.

'Ihe treatment of crude naphtha in the manner just described is one exemplication of myk invention which may be applied to other distillates and oils Ithan such crude naphtha; and I may in treating crude naphtha use only two stills or more than three stills, the number shown. I regard my invention as being applicable to cases where it is desired to tillates in order uniform cuts or fractions with a uniform u ndistilled high boiling residual oil or fraction.

It will be obvious that with the present devised a way of distillation 1n which with struction, I can separate a given amount of crude naphtha into gasolene, naphtha and enzin with a comparatively small amount of steam, and with a saving of time. The

steam-distil petroleum dis-4 to obtain a plurality ofV a comparatively cheap' conseveral distilled products obtained are of uniform quality and do not need redistillation. In one operation, I am obtaining gasolene, naphtha and benzin with closer boiling points. There is also a saving in the amount of condenser water necessaryand a saving in the amount of ground space required.

What I claim is l. 'Ihe process of continuously redis'tilling petroleum products which comprises passing a continuous current of a petroleum oil to be distilled through a plurality of successive stills, each such 'still being provided with a vapor outlet and dephlegmating column, and the liquid supplied to each such still first passing through such dephlegmating column, and the liquid in each such still being caused to flow from end to end thereof in a' more or less tortuous passage for the purpose of complete exhaustion therein.

2. rIhe process of continuously redistilling crude naphtha for the purpose of making definite cuts or fractions therefrom which comprises continuously supplying such crude naphthato and through a plurality of stills in series, the oil feeding each such still being with the vapors from such still prior to entering the still and the oil in the still being end of such still passage.

3. rIhe process of continuously distilling petroleum products which comprises passing a continuous current of petroleum oil to be in a more orless tortuous caused to How from end to' distilled through a plurality of successive stills, the vapors Vfrom one still being conducted past and contacted with the oi from another still outside of said stills and the said oil being delivered from said outside source to the still the vapors from which it has passed.

a. The process of continuously distilling petroleum products which comprises establishing and maintaining a plurality of stills operating in series, passing the oil from one still outside of said still and in countercurrent to the vapors from another still, and then passing said oil into said second still.

5. ln a petroleum still, the combination of a plurality of steam heated stills arranged in series for the iow of liquid therethrough, each such still being provided with a dephlegmating column with the feed of liquid to each still through such dephlegmating column, the liquid flowing1 from each preceding still passing through t e dephlegmating column of the next succeeding still, and each such still being provided with means for causing a flow of liquid in a tortuous path from end to end of the still.

6. ln a petroleum still, the combination of a plurality of steam heated stills arranged in series'for the ioW of liquid therethrough, each such still being provided with a dephlegmating column with the feed of liquid to each still through such dephlegmating column, the liquid flowing from each preceding still passing through the dephlegmating column of the next succeeding still, each such still being provided 'with means for causing a. iow of liquid in a tortuous path from end to end of the still, and such plurality of stills being mounted in vertical arrangement so that the flow of liquid from still to still may be downward through the serles.

7. In a. petroleum still the combination of a plurality of heated stills arranged in series for the flow of oil therethrough, each still beingprovided with means for delivering vapor therefrom and returning condensed liquid thereto and a dephlegmating column for each still, and connections arranged for delivering oil from one still to a succeeding still in the series past the vapors rising from such succeeding still.

8. In a petroleum still the combination of a plurality of heated stills arranged in series for the flow of oil therethrough, each still being provided with-means for delivering vapor therefrom and returning condensed liquid thereto, and connections arranged for delivering oil from one still to a succeeding still in the series past the vapors rising from such succeeding still, and means for separately withdrawing and collecting the vapors from each still after such vapors have been contacted with the oil being delivered by the preceding still.

In testimony whereof, I aliix my signature hereto.

GEORGE L. PRCHARD.

Witnesses:

J. G. GLASGOW, HERBERT HENDERSON.

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