US1084016A - Distilling petroleum. - Google Patents

Description

W. C. KOEHLER & L. LINK. DISTILLING PETROLEUM. APPLICATION FILED JULY 5, 1910. RENEWED JUNE 26, 1913.

LUSLUJL 6. Patented Jan. 13, 1914.

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I l I I 1 l I l l I I SAT #1 l T TENT OFFICE.

WILLIAIVI C. KOEHLER AND LUDWIG LINK, F ELIZABETH, NEIJV JERSEY, ASSIGNORS TO STANDARD OIL COMPANY, OF- BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

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Application filed July 5, 1910, Serial No. 570,373.

To all whom it may concern:

Be it known that we, IVILLIAM G. KonnLnn and LUDWIG LINK, both citizens of the United States, residing at Elizabeth, in the county of Union and State of New Jersey. have invented certain new and useful Improvements in Distilling Petroleum, of which the following is aspecification.

This invention relates more particularly to the distillation of the lubricant or lubricant and wax yielding fraction of crude petroleum at temperatures above (350 F. and with protection of the vapors against undue cooling before they pass over to be condensed as distillate, so as thereby to obtain distillate which shall contain the decomposable but undecomposed (or only slightly decomposed) hydrocarbons of said fraction and shall consequently be well suited for use as a lubricant and wax yielding material where the crude petroleum yields paraffin wax, or as-a lubricant stock simply where it does not; for it is well known that the suitability of distillate as such material or stock is impaired when its decomposable hydrocarbons are cracked (decomposed) to more than a slight extent (if at all) and that undue cooling of the vapors before they pass over to be condensed as distillate results in objectionable cracking. But each of the improvements composing the invention is intended to be secured for all the uses to which it can be applied with or without modification. I-Ieretofore'in thus distilling said fraction much of the distillate has had to be rerun before it could be satisfactorily pressed for paraffin wax in the case of distillate from wax yielding petroleum or be given the customary sulfuric acid and alkali treatment in the case of distillate from petroleum having an asphaltic base. In the former case gummy matters have been present which clog the filter press and so prevent the pressing of the distillate at least with facility; and in the latter case asphaltic matters have been present which in the customary treatment with sulfuric acid and alkali unite with the alkali in the form of an emulsion that will not separate on standing. In distilling, for example, the petroleum from the Illinois and Kansas fields (a petroleum which yields paraffin wax) the best results in our experience have heretofore been the production in the crude oil run (along with lighter distillate) of about twenty per cent. of distil- Specification of Letters Patent.

Patented J an. 13, 191d.

Renewed June 26, 1913. Serial No. 775,964.

late available as lubricant and wax yielding material without further distillation and about eight and a half per cent. of distillate (termed slop) which must first be rerun. In rerunning nearly a fourth as much slop is again produced, making the total amount of distillate to be rerun constantly about ten and a half per cent. of this kind of crude oil. Vi e have discovered that it is possible materially to reduce the percentage of slop produced in the crude oil run in distilling the lubricant or lubricant and wax yielding fraction of petroleum as aforesaid; and we thus are able to effect a substantial saving in expense of working as compared with any previous process for performing such distillation with which we are acquainted; while the loss by decomposition may even be less than heretofore, when the decomposition in rerunning is taken into account. IVe have found (first, as we believe) that much of the vapors of lubricant or lubricant and wax yielding character which are accompanied by gummy or asphaltic matters in their passage from the still can be freed from such matters before said vapors are condensed as dis tillate by a suitably extended travel of the suitably cooled vapors in contact with oppositely flowing condensate in connection with a return of said condensate to the oil in distillation, without. countervailing loss by decomposition of hydrocarbons or otherwise.

Conditions of cooling and travel which we have found efficient will be hereinafter set forth by way of example. It is only essential, first, that the cooling should be sufficient to effect the condensation of the gummy or asphaltic matters and not so far below the contemporaneous temperatures of the oil in distillation that the advantage otherwise of the new or improved process over the prior state'of the art would be more than offset by the detrimental effects of increased decomposition and evaporation in the still which would result from excessive cooling of the vapors; and, second, that the travel of the suitably cooled vapors in contact with oppositely flowing condensate on its way back to the oil in distillation should be sufiicient to free said vapors practically from said gummy or asphaltic matters. After the vapors have passed over to be condensed as distillate, they are subjected to fractional condensation with flow of vapors and condensate in opposite directions in contact with each other in order to obtain distillate of lubricant or lubricant and wax yielding character as free as may be from more volatile hydrocarbons; and the facility or difficulty with which the so obtained distillate can be pressed for wax so that pressingwithout rerunning would or would not be preferable to rerunning and subsequent pressing (in the case of wax yielding petroleum) and the ability or inability of the distillate to separate on standing from the alkali of the customary sulfuric acid and alkali treatment when it is subjected thereto (in case of other petroleum) will indicate whether it. has or has not beenmade practically free from gummy or asphaltic matters. If not thus free therefrom the vapors may be made to travel longer in contact with the oppositely flowing condensate with or without additional cooling as may be considered necessary or expedient. It is considered best to reduce the volume of this condensate as much as is consistent with the practical freedom of the vapors from said gummy or asphaltic matters when they pass over to be condensed as distillate. The distillation of the said fraction as a whole is best performed as hereinafter described; and the apparatus, which is hereinafter described, is best employed for the purpose.

Figure 1 of the accompanying drawings is a plan View of said apparatus; Fig. 2 is an elevation of the same, partly in vertical v longitudinal section; and Fig. 3 is a detail view of one of a number of small relief valves forming part of said apparatus.

The fire heated still a,.-say in the form of a horizontal cylinder and of about a thousand barrels capacity, more or less, suitably jacketed to prevent undue cooling of the vapors before they leave the vapor space, is provided with a valved charging line b, a valved run back 0, and a valved steaming out line d. It is connected by a vapor pipe e (say twelve inches in internal diameter and about twenty five feet long) with the lower part of chamber f provided with a heat retaining jacket and being, say, about seven feet in internal diameter and about eight feet high. The vapor pipe e has a short upright portion at its inlet end; and it thence descends toward its outlet end. Within chamber 7 are baflies in'the form of cobble stones 9 (say from about four to about eight inches in diameter) loosely piled together to a depth. say, of about four feet and resting upon the grating it above the outlet end of the vapor pipe e.

Above the chamber 1 is an air cooled tubular condenser composed of, say, sixty pipes 2', each about eleven feet in length and about four inches in external diameter, set in an inclined position between the tube sheet]: at top of chamber 1 and the annular header Z. As shown in Fig. 3 at the upper-end of each pipe 71 is a light valve m (say about thirty three ounces in weight) with an opening '27, therein of smaller diameter than the inside of the pipe 2' (say an opening of about an inch and a quarter in diameter) The restricted openings 12, tend to equalize the currents in the several pipes 2'; and one or more of the valves m would rise and release the pressure in said pipes i if it should at any time become excessive.

The pipes i are inclosed in a casing 72 which at the top fits around the header Z and which has inlet openings 9 at the bot tom for inflow of air from the surrounding atmosphere. Each inlet is provided with a valve 1"; which can be opened to the extent desired, or can be closed. The casing is open on top through the annular header Z, but closed at bottom except for the valved inlets g.

From the interior of header Z a vapor pipe 8 leads to the bottom of an air cooledtubular condenser 25. From the top of this latter a vapor pipe u connects with the water cooled condenser '20 formed ofa single pipe which is immersed in the water of tank a; and whose upperend only is represented, the rest of it being broken away for simplicity of illustration. The pipes 5, 8, 9 and 10- are similarly represented. The tank 00 is supplied with water by pipe 3 and provided with an overflow 2.

Between the chamber f and the pipes 71 are means (in the form as shown of a saucer 2 and a valved outlet 3 from said saucer) forenabling (at the will of the operator) the condensate from pipes i to be supplied to chamber f or to be otherwise disposed of. As shown, the saucer outlet 3 connects through a trap 4 with a-distillate draw off 5, which is immersed in the water of tank a: for cooling.

The chamber f has a liquid outlet 6, which is connected with said trap 4 and distillate draw ofi' 5, also with the run back 0, also with a second-valved distillate draw off 8 which is not immersed in the water of tank a; and is consequently of higher temperature than pipe 5, and (if so desired) also with a valved draw off 9 (indicated in dot-ted lines) which is suitably trapped and immersed in the water of tank 2:. In outlet 6 between the trap and the draw Oils 8 and 9 is a valve 7.

Llhe condenser t has its liquid outlet connected with a trapped and valved draw off 10 immersed in the water of tank at. As shown, said outlet is also connected with the run back 0, namely, by a valved branch pipe 11.

The vapors from still a, after cooling to a certain extent in vapor pipe e, enter the lower part of chamber f and, after passing up. between the stones g, proceed thence through pipes z, header Z, vapor pipe 8, air

cooled condenser t, vapor pipe to and water L cooled condenser 4.0; In this last all but the non-co-ndensable gases (and very lightest I in "liquid hydrocarbons) are reduced to the liquid state, 'the uncondensed gases (and vapors) passing off in :the known way, to.

be disposed of as may be desired.

- fcrred) either to the run back or to the draw oit 5, to thedraw off 8 of higher temperature, or to the draw off 9, should this last be provided.

By opening and closing the proper valves the condensate'from the pipes ican be allowed to fall into the chamber f, thence to.

, distillation above 650 F.

flow away through one of the pipes con-* nected with pipe 6; or it can be diverted by saucer outlet 3 direct to the distillate draw The condensate from condenser is drawn off through pipe 10; or, if desired (by changing the through the back 0. The condensate from condenser w is drawn 01f from the outlet thereof in ordii narily at least a sufficiently cool state.

branch pipe 11 to the run} In distilling the lubricant and wax yield l ingfraction of crude petroleum, say from the Illinois and Kansas fields, such petio leum can be deprived in any known or suit able way of its more volatile fractions, representing about 58 per cent. of-the crude oil '1 by volume; and the so obtained residual oil (representing about 42 per cent. of the crude oil) can then be charged into the still a; but it is more advantageous'to supply the still a with the crude oil itself; or with an undistilled residual oil therefrom containin more or less of said more volatile fractio ns in addition to the lubricant and wax yielding fraction. In the latter cases thereis no interruption to the distillation when said more volatile fractions have been removed; but whereas in removing them the run back 0 is open and the saucer outlet 3 closed (draw offs 8 and 9 and valve 7 also closed) when they have been removed the run back 0 is closedand the valve 7 is opened (saucer outlet 3 and draw ofi's 8 and 9 remaining closed). In the former case the still for distillation of the lubricant and wax yielding fraction may be brought in either with the run back 0 open and valve 7 closed or conversely (saucer outlet 3 and draw ods 8 and 9 being closed). In any case d 1st1llat1on of the lubricant and wax yielding fraction is in due course carried on with the 011 in in temperature and with the run back 0 closed. valve 7 being open and saucer outlet 3 and draw-offs 8 and 9 being closed; so that all the condensateformed after the vapors leave the ordivalves), it can be delivered i maining closed);

nary vapor space of the still and before they leave the header 1, exceptythe small amount formed in the upright part of a vapor plpe e, is collected as distillate through the pipe 6 and draw of]? 5; while the wellrectified vapors pass on by pipe 8 to the condenser t. In this latter further condensation takes place; and the condensate therefrom is collected as distillate through the draw ofi' 10. The uncondensed vapors pass 75 by pipe u to condenser w; from which the condensate is collected as distillate; while.

the gases and any uncondensed vapors pass off to be burnt under the still or to be. otherwise disposed of.

Satisfacto-ry lubricant and wax yielding dlstillate should be received from draw 911' 5 while the gravities of samples taken from the stream at itsoutlet end are changing from about 31 4 10 '13. at 60 F. (which 151 about the gravity of the--first distillate so received whichbelongs to thisffraction of the crude oil under consideration) toabout 26 B. The viscosities of these samples should range from about 65 seconds to'ab'out "1,08

seconds measured at F. by Saybolts Universal Viscosimeter. They should first I exhibit cloudiness, due to solidification of the paraflin wax therein, at temperatures ranging from 56 should range in temperature from. about 698 F. to about 745. F. The vapors pass over to be condensed as distillate almost as 10 F. to about 55 tion during this period may well occupy about 12 hours,

the crude oil, about 20 per cent. being received by the draw off 5 and the remainder from the draw off 10 and condenser 20.

When the distillate from draw cit 5 exhibits a gravity of about 26 B. it would become unsatisfactory (according to our experience with sald Illinois and Kansas 011) if the distillation were continued in the same manner and would have to be-rerun before it could be'pressed, at least with equal ad- To avoid the formation of this distillate (or slop) as soon as (or just before the lead him to expect vantage. unsatisfactory it malges' its appearance workers experience may it) thesaucer outlet 3 is opened; so that only condensate from the pipes i is collected as distillate through draw of? og and the run back 0 is also opened, the pipe 6 being closed at valve 7 (and draw ofYsS-and 9 re- F. to 78 F; when the samples are gradually reduced to sufliciently low temperatures. The oil in distillation from 620 F. to about 105 F. below the oil in distillation. The distillaand the total distillate collected equal about 27 per cent. by volume of 110 so that the condensate 68 F. and about 76 F. Theoil in distillation should range in temperature from about 745 F. to about 795 F. The vapors pass 'over to be condensed as distillate only when they have reached the upper partof chamber f; so that subsequently formed condensate can be received in the saucer 2; and

- centby volume of the crude oil, about 7% when they thus pass over they should range in temperature from about 67 F. to about 685 F. or from about 71 F. to about 115 .F. below the oil in distillation. The distillation with saucer outlet 3 and run back 0 open may well occupy about 6 hours, and the total distillate collected equal about 9 per per cent. being received through saucer outlet 3 and draw off 5' and about 1% per cent. by drawofif 10 and condenser w.

Whensth'e distillate from draw ofi 5 exhibits. a -\gravity'of about 24 B., in order to enable the stills contents to be dried out or coked, .the run back 0 and the saucer outlet 3 are both of them closed and the valve 7 inrpipe 6 is openedyso that the vapors pass over to be condensed as distillate .just after they leave the ordinary vapor space of the still. When the distillate becomes too thick atthe temperature of the draw off 5, the

valve 7 is closed and the draw off 8 is opened for the passage throli hit of the'distillate.

The distillation after c osure' of saucer outlet 3 and run back a may occupy'about three hours and yield a total distillate equal to about 2 per cent. of the crude oil. About half of it would be received through the draw offs 5 and 8 (in succession) and about half from the draw off 10 and condenser w (concurrently until the flow from one of them ceases). The distillate which at this period would be received through the draw off 5 would (in our experience) be unsatisfactory without rerunning. That which would be received through the draw ofl 8 would be wax tailings.

The coke and loss during an uninterrupted distillation of all fractions of a charge of crude oil may represent about four per cent. by v0lume of the'crude oil.

In distilling the lubricant or lubricant and wax yielding fraction the vapors which are cooled in pipes 71 should have a temperature between 4.00 F. and 600 F. when they leave the header Z. By setting the valves r this cooling in pipes i can be regulated m' accordance with the indications furnished by the distillate from the drawofl's 5 and 10, so as to obtain distillate of lubricant and Wax yielding character suitably free from more volatile hydrocarbons. These latter pass on to the condensers t w and are collected as distillate as long as condensate runs therefrom.

The particular figures which have been given are by way of example, in order' the better to enable those skilled the art to practise the invention, and not as restricting the invention thereto; and modifications in process, apparatus or both can be -made indefinitely so long as the substance is taken of any one or more of the hereinafter Written claims.

In drying out or coking the contents of the still, the run back 0 can be closed and the part thereof. So, too, it is not necessary that all the lighter and all the heavy end of said fraction'should be distilled as herein above described therefor, respectively; but any substantial and appropriate part of either of them may beso distilled. In fact, as mentioned, by reason of the difliculty (or practical impossibility) of drying out or coking the stills contents with run back 0 open, it is desirable to stop the return of condensate from chamber 7 before all the heavy end of the oil is received. All or any substantial and appropriate part of the condensate formed in the descending part of yapor pipe 6 and in chamber 7 in the distillation of said heavy end when the saucer outlet 3 is open can be returned to the liquid oil in distillation; although it is designed that all of it should be soreturned. It is also designed that after the condensation of vapors as distillate in pipes i' (or in vapor pipe e, chamber f and pipes 2', according to the case) all.

the remaining vapors should, as far as possible, be condensed in condensers t and w; but,

if desired, part only of them may be socon= densed.

In the hereinafter written claims, there- 'fore, the respective recitals are to be con strued to apply to all, or to any substantial and appropriate part, of the therein specified fluid or fluids.

It is believed that the general designation of lubricant or lubricant and wax yielding fraction of crude petroleum designates the part intended sutficiently for all the purposes of this specification; but, should greater preclslon be desired, said fraction of mam 'a charge of the same under atmospheric pressure with gradual rise oftemperature and introduction into the liquid oil of free steam .in suflicient volume to prevent cracking,

samples of distillate taken in succession at "the outlet of .the customary water cooled condenser exhibit either a viscosity as high as 65seconds at 100 F. by Saybolts Unlversal Viscosimeter or a cloud at a temperature,

I as high at 50 F. (whichever characteristic first appears). When another charge of crude petroleum of the same kind is distilled in any known or suitable way until the undis tilled residue represents this percentage of the crude oil, such residual oilv can be taken to contain substantially the entire lubricant or lubricant and wax yieldingfraction of the crude oil without any portion of another fraction.

In order to secure concordant results, the assays must always be performed under identical conditions; and they may well be performed by using such a laboratory apparatus as is shown in out No. 1286 in the catalogue for 1908 of E. H. Sargent & Company, of 145 Lake Street, Chicago,1llinois, Said apparatus has a copper still of cheese boxform heated by a gas flame underneath;

and it is provided with means for introduc-' ing free steam into the liquid oil in the still. A still with a charging capacity of about ten liters would be large enough; and it should receive a charge about equal to its capacity. In the distillation the heat may be so regulated that hydrocarbon distillate is received from the condenser at the uni, form rate of about fifteen per cent. by volume per hour of the charge of crude oil; and the free steam supply may be so regulated that the stream from the condenser contains water of condensation equal in volume to from a third to a half of the hydrocarbon distillate. The ,steam may be dry and saturated; or it may be slightly superheated The samples of distillate may be two per cent. by volume of the original charge of crude petroleum.

Some petroleum may be of such peculiar character that all of its lubricant or lubricant andwax yielding fraction would be distilled with the separation herein above described as applied to the heavy end of said fraction; and in'such case, of course, the heavy end (no less than the lighter end) of its said fraction would be distilled with such separation. The recital that vapors of the heavy end of said fraction are subjected to certain operations does not of itself require that the vapors of said heavy end only should be subjected thereto.

Advantage over the prior state of the art is efiected by a suitably extended travel of the suitably cooled vapors of said heavy end in contact successively with two lots of oppositely flowing condensate, separately col-- lected as distillate, without the described return of condensate to the oil .in distillation. The conditions of cooling and travel in vapor pipe 6 and chamber f as described are considered. best for the first of the two separations. It is only essential thereto that said cooling should be suflicient to efiect the condensation of the gummy or asphaltic .matters and not as much as to condense practically all of the lubricant or lubricant and wax yielding hydrocarbons, and that the extent of the travel should sufiice for the vapors passing on to be practically free from said gummy or asphaltic matters. The conditions of cooling and travel in pipes 2' as described are considered best for the .tillate received by draw off 9 should become too thick to flow properly at the temperature of the latter. The draw oil 8 would then be opened; the draw off 9 would be closed, saucer outlet 3 remaining open and the run back 0 remaining closed; and distillation would ,be' continued until the. contents of the still should become dried out or coked to the desired extent. lVhile, however, to work in this way would be an advance over the prior state of the art and is, therefore, included in the invention, it is inferior to the working-with thedescribed return of condensate, which latter working more particularly constitutes the invention. For example, without such return, the lubricant and wax yielding fraction of Illinois and Kansas petroleum has been distilled bv us with the production in the crude oil ruh of slop equal to about three and a half per cent/by volume of the crude oil as against about e1ght and a half per cent. by the best prior practice known to us and about one per cent. by our working with the described return of condensate. In the hereinafter written claims the word withdrawing as apphedto-a condensate includes a collection as distillate or a return to the oil in distillation, whichever disposition ofthe condensate may be adopted, said collection and said return belng considered each of them a mode of withdrawal of the condensate.

" In the foregoing description and the accompanying drawings we have exhibited our invention in connection with matters which we are informed and believe "by John .W. Van Dyke and William M. Irish, both of- Philadelphia, Pennsylvania, and which are described and claimed by them in their application of October 4, 1909, No. 520,937 and in divisions thereof. The invention of said Van Dyke and Irish is, of'course, not

claimed in whole or in part by us..

We claim as our invention or discovery: l. The process of distilling petroleumina form which contains the defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum, by heating such undistilled petroleum (eventually at least) to the high temperatures (above 650 F.) necessary to distil the heavy end'of said fraction,

: subjecting the vapors evolved from said heavy end and protected against undue cooling within the ordinary vapor space of the still to such cooling after said' vapors leave said vapor space and to such contact of the so cooled vapors with retrograding condensate that practically all of the gummy orasphaltic content of said vapors is con- .densed and that there is left a residue of uncondensed vapors practically free from gummy or asphaltic matters and consisting -mainly of lubricant (orlubricant andwax yielding) hydrocarbons, withdrawing the V gummy or asphaltic condensate, cooling said residual vapors to effect a condensation of condensate practically free from gummy or asphaltic matters and having a lubricant (or lubricant and wax yielding) character,

' and so continuing until a quantity of heayy 40 end distillate equal to about half of the distillable portion of said-heavy end as a minimum has been collected, substantially as described. K 2. The process of distilling petroleum in a form which contains the defined lubricant (or lubricant and'wax yielding) fraction of I or asphaltic content of said vapors is 0011-.

V densed and that there is left a residue of uncondensed vapors practically free from gummy orasphaltic matters and consisting mainly of lubricant (or lubricant andrwax yielding) hydrocarbons, withdrawing the gummy or asphaltic condensate, cooling said residual vapors t0 efiect'aicondensation of were originally, first and jointly invented as them, .drawing off as distillate so formed.

subjectin heavy en 7 and protected against undue coola formwhich contains the defined lubricant (or lubricant and wax yielding) fraction ofthe crude petroleum, by heating such undistilled petroleum (eventually at least) to the high temperatures (above 650 F.) necessary to distil the, heavy end of said fraction, subjecting the vapors evolved from said heavy end and protected against undue cooling within the ordinary vapor space of the still to such cooling after said vapors leave said vapor space and to such contact 96 of the so cooled vapors with retrograding condensate that practically all of the gummy or asphaltic content of said vapors is condensed and that there is left a residue of uncondensed vapors practically free from gummy or asphaltic matters and consisting mainly'of lubricant (or lubricant and wax yielding) hydrocarbons, returning said gummy or asphaltic condensate to the oil. in

distillation, cooling said residual vapors to oo effect a condensation of them, drawing of? as distillate so formed condensate practically free from gummy or asphaltic matters and having a lubricant (or lubricant and wax yielding) character, and so continuing until a quantity of heavy end distillate equal to about half of the distillable portion of said heavy end as a-minimum has been collected, substantially as described.

4g. The process of distilling petroleum in a fprm which contains the defined lubricant (or' lubricant and wax yielding) fraction of the crude petroleum, by heating such undistilled' petroleum (eventually at least) to the high temperatursf(ab0ve'650 F.) necessary to distil the heavy end of said fraction, V

thevapors evolvedffrom said in within the ordinary vapor space of the strl to such cooling after said vapors leave said vapor space and tolsuchcontact of theso cooled vap orsiwith retrograding :conden j satethatpractically all of; the'gummyor asphaltic content of said vapors is condensed and that there is left alresidue or uncondensed'vapors practically free from gummy or asphaltic matters and consisting mainly of lubricant (or lubricant and waxy1elding) hydrocarbons withdrawing the gummy'or asphaltic condensate, cooling said Amie residual vapors to efiect a condensation 'oi them, drawing'ofi as distillate so formed lcondensate practically free from gummy or lubricant and wax yielding), character, and

asphaltic matters and having a lubricant (or so.cont'inuing until a quantit of heavy end distillate equal to about hal of the distillable portion of said heavy end as a minimum has been collected, the distillation of said heavy'end being carried on at least eventually with collection as distillate of mmy or asphaltic condensate, substantially as described.

so cooled vapors with retrograding condensate that practically all of the gummy or asphaltic content of said vapors is condensed or asphaltic condensate, ,coolingsai and that there is left a residue of uncondensed vapors practically free from gummy or asphaltic matters and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, withdrawing the (gummy residual vapors to effect a condensation of them, drawing oil as distillate so formed condensate practically free from gummy or asphaltic matters and having a lubrlcant (or lubricant and wax yielding) character, and so continuing until a quantity of heavy end distillate equal to about half of the distillable portion of said heavy end as a minimum has been collected, the distillation. of said heavy end being carried on at leasteventually with collection as distillate of gummy or asphaltic condensate through draw ofls respectively of lower and of higher temperatures, substantially as described.

6. The process of distilling petroleum in a form which contains the defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum, by heating such undistilled petroleum (eventually at least) to the high temperatures (above 650 F.) necessary to distil first the lighter end and afterward the heavy end of said fraction, subjecting the vapors evolved from said lighter end and protected against undue cooling within the ordinary vapor space of the still to such cooling after they leave said vapor space as to effect a condensation of said vapors. drawing oil so formed condensate as distillate, subjecting the vapors evolved from said heavy end and protected against undra cooling within the ordinary vapor vapors leave said vapor space and to such contact of the so cooled vapors with retro-J grading condensate thatpractically all of the gummy or asphaltic content of said vaporsis condensed and that there is left a residue of uncondensed vapors practically free from gummy or asphaltic matters and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, returning the gummy or asphaltic condensate to the oil in distillation, cooling said residual vapors to effect acondensation of them, drawing oii as distillate so'formed condensate practically free from gummy or asphaltic matters and havin a lubricant (or lubricant and wax yielding character, and so 011- tinuing until a quantity of heavy end distillate equal to about half of the distillable portion of said heavy end as a minimum has been collected, the lighter end condensate which is drawn OK as distillate being formed from vapors which pass over to be so condensed before they have been cooled even approximately to the extent to which said heavy end vapors are cooled in order to form the gummy' or asphaltic condensate which is returned to the oil in distillation, substantially as described.

7. The process of distilling petroleum in a form vwhich contains the defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum, by heating such undis- ,tilled petroleum (eventually at least) to the high temperatures (above 650 F.) necessary to distil first the lighter end and afterward the heavy end of said fraction, subjecting the vapors evolved from said lighter end and protected against undue cooling within the ordinary vapor space of the still to cooling by means of three successive sets of cooling devices after said vapors leave space of thestill to such cooling after said ioo said vapor space and to contact with the un1tedretrograding condensates: from the w first two of said coolings, drawing off said united condensates as a distillate and con densate' from the third of said coolings as a distinct distillate, subjecting the vapors evolved from said heavy end and protected against undue cooling within theordinary vapor space ofthe still to cooling by means of the same successive sets of coo-ling devices to which said lighter end vaporswere subjected and to contact with etrograding condensate from the first of siid coolings, withdrawing the three heavy end condensates separately, those from t'hesecond and third coolings being drawn off as distinct. distillates, and so continuing until quantities of heavy end distillates equal together to about-half of the distillable portion of said heavy end as a minimum have beencollected. the first of said coolings of the heavy end vapors and the-contact of, the so cooled vaporswith retrograding condensate being vapors practically free from gummy or assary to distil first'the lighter end and after- I ward the heavy end of saidfraction, subretrograding condensate being such that 'heavy end condensates separately, those minimum have been collected, the first of a residue is left of uncondensed vaporspracheating petroleum in a form-that contains thedefined lubricant (or lubricant and wax such that practically all of the gummy or asphaltic contact of said vapors is condensed and that a residueis left of uncondensed phaltic matters and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, substantially as described.

8. The process of distilling petroleum in a formwhich contains the defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum, by heating such undistilled petroleum (eventually at least) to the high temperatures (above 650 F.) necescondensates flow over said battles in contact with said vapors, drawing ofi said united condensates as a distillate and the conden sate from the third of said coolings as a dis- 1 tinct distillate, subjecting the vapors evolved from said heavyend and protected against undue cooling within the ordinary vapor space of the still to cooling by means of the same successive sets of cooling devices towhich said lighter end vapors were subjected and to contact withretrograding condensate from the first of said coolings in passing over said bafiles, withdrawing the three from the second and third coolings being drawn oil as distinct distillates, {LIId'SO continuing until quantities of heavy end dis tillates equal together :to about half of the distillable portion of said heavy end as a said coolings of the heavy end vapors and the contact of the so cooled vapors with practically all of the gummy or asphaltic content of said vapors is condensed and that tically free from gummy or asphaltic matters and consisting mainly of lubricant 1 (or lubricant and'wax yielding) hydrocarbons,

substantially asdescribed.

9. Apparatus for distilling petroleum, consisting of a still which is designed for yielding) fraction ofcrude petroleum (eventually at least) to the high tempera tures (above 650 F.) necessary to distil the heavy end of said fraction and which is arranged to protect the. evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means arranged to subject the passing vapors to such cooling and to such contact with retrograding-condensate that in the'distillation of said heavyend practically all of the ac-' companying gummy or asphaltic matters can be separated thereby from uncondensed vapors representing about half of thedistillable portion of said heavy end as a minimum and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, additional condensing means, connections for conveying vapors from the ordinary vapor space of the still to the first mentioned condensing means and from the lat ter to said additional condensing means, appliances for withdrawing condensate formed by the first mentioned condensing means, and a distillate draw-oil leading from said additional condensing means and arranged to keep the distillate conveyed thereby distinct from the condensate withdrawn by said appliances from the first mentioned condensing means, substantially as described.

10 Apparatus for distilling petroleum, cc-ns1st1ng of a still which'is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding) fraction of crudepetroleum (eventually at least) to the high temperatures (above 650 F.) necessary'to distil the heavy end of said fraction and. which is arranged to protect the evolved vapors 7 against undue cooling within-the ordinary vapor space of said still, condensing means arranged-to sub ect the passing vapors to such cooling and to such contact with retrograding condensate that in the distillation of said heavy end practically all of the accompanying gummy or asphaltic matters can be separated thereby from uncondensed vapors representing about halfof the distillable portion of said heavy end as a minimum andiconsisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, additional condensing means arranged to effect acondensation vof vapors first at higher and then at lower temperatures and thus to form condensates of respectively heavier and lighter gravit ies, connections for conveying vapors from the ordinary 'vapor space of the still to the first men- 'tioned condensingimeansand from the latter to said additional condensing means,

appliances for wi thdrawing condensate formed by the first mentioned condensing means, and distillate draw ofi's leading from difierent'parts of said additional condensing means and arranged to keep the respective distillates conveyed thereby distinct from each other and from the condensate withdrawn. by said appliances from the first mentioned condensing means, substantially as described.

11. Apparatus for distilling petroleum, consisting of a still which is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding) fraction of crude petroleum (eventually at least) to the high temperatures (above 650 F.) necessary to distil the heavy end of said fraction and which is arranged to protect the evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means arranged to subject the passing vapors to such'cooling and to such contact with retrograding condensate that in the distillation of said heavy end practically all of the accompanying gummy or asphaltic matters can be separated thereby from uncondensed vapors representing about half of the distillable portion of said heavy end as a minimum and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, additional condensing means, connections for conveying vapors from the. ordinary vapor space of the still to the first mentioned condensing means and from the latter to said additional condensing means, appliances for returning condensate formed by the first mentioned condensing means to the oil in distillation, and a distillate draw ofl leading from said additional condensing means, substantially as described.

12. Apparatus for distilling petroleum, consisting of a still which is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding-)- fraction of crude petroleum eventually at least) to the high temperatures (above 650 necessary to distil the heavy end of said fraction and which is arranged to protect the evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means arranged to subject the passing vapors to such cooling and to such contact with retrograding condensate that in the distillation of said heavy end practically all of the accompanying gummy or asphaltic matters can be separated thereby from uncondensed vapors representing about half of the distillable portion of said heavy end as a minimum and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, additional condensing means, connections for conveying vapors from the ordi-- nary vapor space of the still to the first mentioned condensing means and from the latter to said additional condensing means, appliances for withdrawing condensate formed by the first mentioned condensing means, and a distillate draw ofl leading from said additional condensing means and arranged to keep the distillate conveyed thereby distinct from the condensate withdrawn by said appliances from the first mentioned condensing means, said apparatus including a distillate draw oli'ileading from the first mentioned condensing means, substantially as described.

18. Apparatus for distilling petroleum, consisting of a still which is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding) fraction of crude petroleum (eventually at least) to the high temperatures (above 650 F.) necessary to distil the heavy end of said fraction and which is arranged to protect the evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means arranged to and to such contact with retrograding condensate that in the distillation of said heavy end practically all of the accompanying gummy or asphaltic matters can be separated thereby from uncondensed vapors representing about half of the distillable portion of said heavy end as a minimum and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, additional condensing means, connections for conveying vapors from the ordinary vapor space of the still to the first mentioned condensing means and from the latter to said additional condensing means, appliances for withdrawing condensate formed by the first mentioned condensing means, and a distillate draw ofi leading from said additional condensing means and arranged to keep the distillate conveyed distinct from the condensate withdrawn by said appliances from the first mentioned condensing means, said apparatus including distillate draw oils leading from the first mentioned condensing means and arranged to be maintained at higher and at lower temperatures respectively, substantially as described.

14. Apparatus for distilling petroleum, consisting of a still which is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding) fraction of crude pertoleum (eventually at least) to the high tempera tures (above 650 F.) necessary to distil the heavy end of said fraction and which is arranged to protect the evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means arranged to subject the passing vapors to such cooling and to such contact with retrograding condensate that in the distillation of said heavy end practically all of the accompanying gummy or asphaltic matters can be separated thereby fromuncondensed vapors representing about half of the distillable portion of said heavy end as a minimum and consisting mainly. of lubricant (or lubricant and wax yielding) hydrocarbons, ad-

subject the passing vapors to such cooling densing means and from the latter to said additional condensing means, appliances for returning condensate formed by the first mentioned condensing means to the oil in distillation, a distillate draw off leading from the first mentioned condensing means, and a distillate draw off leading from said additional condensing means, substantially as described.

15. Apparatus for distilling petroleum, consisting of a still which is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding) fraction of crude petroleum (even-' itually at least) to the high temperatures (above 650 E) necessary to distil the heavy end of said fraction and which is arranged to protect the evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means which include three successive sets of cooling devices connected in series for passage of the residual vapors from'each preceding to the following set of cooling devices and adapted the first set for bringing the passing vapors into contact with retrograding condensate and the second set for delivery of condensate therefrom to the'upper part of the first set, connections for conveying vapors from the ordinary vapor space of the still to the first of said sets, separate distillate draw ofis leading from the second and third of said sets respectively, and appliances for withdrawing condensate from the first of said sets, which appliances include a distillate draw 01f leading from the first of said sets, the first of said sets being arranged to subject the passing vapors to such cooling and to such contact with retrograding condensate that in the distillation of said heavy end practically all of the accompanying gummy or asphaltic matters can be separated thereby from uncondensed vapors representing about half of the distillable portion of said heavy end as a minimum and consisting mainly of lubricant (or lubricant and wax yielding) hydrocarbons, substantially as described.

16. Apparatus for distilling petroleum, consisting of a still which is designed for heating petroleum in a form that contains the defined lubricant (or lubricant and wax yielding) fraction of crude petroleum (eventually at least) to the high temperatures (above 650 necessary to distil the heavy end of said fraction and which is arranged to protect the evolved vapors against undue cooling within the ordinary vapor space of said still, condensing means which include (first) a set of cooling devices whereof a chamber with baflies therein for bringing the passing vapors into contact with retrograding condensate forms part, and (second) a set of cooling devices whereby the vapors are passed in subdivided streams between closely approached heat removing surfaces, and (third) another set of cooling devices, the three sets of cooling devices being connected in series for the passage of the residual vapors from each preceding to the following set of cooling devices and the second mentioned set of said cooling devices being adapted for delivery of condensate therefrom to the upper part of said chamber, connections for conveying vapors from the ordinary vapor space of the still to the first mentioned set of cooling devices, separate distillate draw oifs leading fromthe second and third of said sets respectively, and appliances for withdrawing condensate from the first of said sets, which appliances include a distillate draw ofi' leading from the first of said sets, the first of said setsbeing arranged to subject the passing vapors to such cooling and to such contact with retrograding condensate that in the distillation of said heavy end practically all of theaccompanying gummy or asphaltic matters can be separated there- WILLIAM C. KOEHLER. LUDWIG LINK.

\Vitnes ses:

CHARLES G. BLACK, GEO. W. Gonnon.

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