US1448709A - Art of oil distillation - Google Patents

Description

J. E. SCHULZE ART op om DISTILLATION Filed Mar. 18,

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s Patented Mar. 13,ig23.

JOHN E. SCHULZE, F CHICAGO, KLLINOIS, ASSIGNOR TO RED RIVEB-REFINING COMPANY, INC., 0F SHREVEPORT, LUSINA, A. CORPORTIGN OF DLUISIANA.

ART 0F OIL DISTILLATON.

Application lei March 18, 1922. Serial No. 544,931.

To all 'whom it may concern.'

i Be it known that I, JoHir E. SCHULZE, a.

citizen of the United States, residing at Chicago,"county of Cook, State of Illinois, have .invented certain new and useful Improvements in the Art of' Oil Distillation; and Ido hereby declare the following to y be a full, clear,and exact description of the invention, suchl as will enable others skiiled l0 in the art to which it appertains to make and use the same.

This-invention relates to art of oil distillation; and itv relates more particularly to distillation of mineral oils, such' as petroleum, 115 shale oil, distillates, residua, and the like, under conditions so controlled that valuable Y' products are obtainable having novel characteristics that render said products superior to those of comparable types heretofore knwn in the art. In general, the process o-f the invention is characterized by distillation under 4reduced p-ressure, and particularly under an absolute pressure not exceedingabout Qmiilimeters of mercury as an upper limit; jwhile' .distillation at very much lower pressures, saynot to exceed 5 millimeters of mercury andmost desirably still lower, offersadvantages that are particularly noteworthy and remarkable and is a feature of my novel y ,process in` some of its best embodiments.

` The novel process as practiced to greatest advantage also includes, as an important fac.- ytor, control of the di tillation and determi- `nationvo-f-the successive lubricating cuts or fractions by observation of one or more physical characteristics of real significance, such as viscosity, flash point, and fire point, rather than by observation of gravity as has heretofore been the practice. It is to be understodd that the invention also includes the`novel commercial products resulting from the process and definitely distinguishable from -products heretofore obtainable; as well as novel apparatus inwhich the processmay `he carried out.

v Petroleum 1s .a mixture of a great variety-,Y` of hydrocarbons with widely varying boilingpoints, viscosities and other characteristics;y

In refining petroleum, for the production of' iiluminating oils, fuels and lubricantsggthe problem lis' to separate 'out' certain groups of' hydrocarbons 'bydistillatiom such a group being known as affcut, or fractionJLIn the ordinary or usual distillation methods of refining, the narrowness of a cut, as shown for example by the range of boiling points' `cause the narrower the cut, the higher the boiling point of the most volatile constituent of an oi1 of given average boiling point or viscosity, viscosity rather than boiling pointbeing the property upon which specificationsfor lubricants are ordinarily based. The

.volatile portion, or light ends, of a cut as obtained in prior manufacturing practice are yobjectionable in a lubricant, both on account of their causing greater losses by evaporation in use and because" it is the light ends which cause oxidation and deteriorate. On the other hand, the extremely heavy ends cause gumming and carbon deposition when.v

the oil is used in an internal combustion engine.

In the usual method of refining there is considerable decomposition or crackihg-as it is called due to overheating, and this occurs throughout practically the entire dis tillation. By cracking is meant a chemical decomposition and degradation, as distinct fromvthe physical separation of fractions of different boiling points, which latter is the desired object of distillation. Cracking roduces both light and heavy products. he light products pass over and are condensed with each of the successive cuts or fractions, thusincreasing the range of viscosity, boilingpoints, etc. of each out. Moreover some-of the cracked products give the oil a -dark color and bad odor, and on this account it is necessary to get ridhof them by expensive and time-consuming treatmentl with sulphuric acid, neutralization, washing and An object of the present invention is to "prevent, or at -leastto greatly reduce, the mechanical carryin over of the oil with the'vapor, as above escrbed, -and,lby avoid.

ing cracking, to obviate the necessity of acid treatment, neutralization, washing and filtration, thus not only saving time and expense but also conserving the oil usually wasted in these operations.

Another object of the inventionis to produce by straight overhead distillation lubrieating oils of viscosities attainable in lubricating oils heretofore only by blending cylinder stock still bottoms with lighter fractions of low viscosity and low Hash and Hre test.

Still another object of the invention is to produce what can be termed narrow cut oils, particularly, lubricating oils, which are distinguishable, respectively, from comparable oils heretofore known by their relatively small range of viscosity, boiling points, and Hash and Hre tests, as determined by eX- amination of initial and Hnal fractions obtained by distilling samples under conditions precluding cracking or decomposition.

Other important objects and advantages of the invention will appear more fully hereinafter.

According to distillation methods heretofore in general use in the practical art, .it has been customary to distil the starting material,`whether it be crude petroleum, or a distillate to be re-run, either with or with- "out the aid of steam, in such, manner and under such conditions that the various cuts or fractlons obtalned each consist of constituents whose physical characteristics vary widely, the physical characteristics of each cut or fraction as a whole being merely an average or resultant of those characterizing the widelyl varying extremes. That is to say, given a lubricating'oil cut, for example., obtained by-straight run overhead distillation as commonly practiced, that cut consists of vconstituents having very vlow speciHc gravity (high Baume) low viscosity, and low Hash and fire test 0n the one hand. and also, on the other, of constituents having very high specific ravity, high viscosity,

and high Hash and re test. Mechanical entrainment of liquid oil particles by the vapors leaving the still Ahas already beenmentioned as one ofthe causes of this trouble. In other words, such a product is merely the equivalent of a blend produced by mixing various oils having the various hysical constants mentioned; and in fact b ends of this kind' are of course extensively produced as a regular practice by manufacturers in order to comply with the ordinary average specifications called for by oil users. Such products, and these are in fact the only type of roducts that have been commercially available heretofore in the art, are inherentl. ly faulty becauseof the above mentioned ,wide variation inthe significant physical constants of the various constituents orv fractions .of which each is always composed.

However obtained, lubricating oils heretofore available all contain on the one hand, a certain substantial proportion of oil having low viscosity, and low Hash and fire test; and, on the other hand, varying proportions and fire test, the proportion depending upon 'the grade of the particular oil under discussion. As a consequence, such oils show excessive consumption when used in internal combustion engines,for example, and are otherwise objectionable.

As before stated, the process of the invention is characterized essentially by the-employment of low absolute pressure in the distilling apparatus. It'is also characterized by the fact that in obtaining even the heaviest lubricating oil overhead cuts hereinafter described, the temperature does not usually exceed about 620i or 630 F. as a maximum. The present process enables lubrieating oils having a viscosity of greater than 100y seconds as measured on the Saybolt universalvisc'osinieter at 212 F., to b eproduced by overhead distillation, something lof oil having high viscosity and'high Hash heretofore unknown in the art; and the new v 4products are characterized by high standbottoms, remaining after distillation of all fractions (including lubricants) that can now be obtained by the usual distillation methods` providing the particular method by which the residuum was obtained was not such as decomposed or cracked the con'- stituents of the residuum tooextensively. Such still bottoms ordinarily have heretofore had no use except as fuel oil or as starting material in certain cracking processes lfor the production of gasolene. Bv

applying the present novel method to such i residua, as much as 80 to 95 perxcent` of the volume thereof maybe obtained in the form lof valuable oil products, including a series of the heavier lubricating oils which are of excellent color and eac-h of which may have a relatively narrow range -of viscosityY a's well as high Hash andre test. The foregoing starting materials are' mentioned. merely by way of example as indlcatlng certain common hydrocarbon "materials to which VJthe present process is applicable;but it is to be understood that reference to these 1,448,709 I Lis typical starting materials is merely illustrative and is not intended to be restrictive,

In carrying out the process of the linvention, it is important that the still and associated apparatus employed therewith be of such character that the whole system-can be kept under the desired low pressure clear through to andv including the receiving I tanks. This requires that the apparatus 4of time and with the minimum obstruction.

Care should be taken particularly to avoid as far as is practicable the refl'uxing of any condensed vapors back into the still. 4In other words, ycracking in the ordinary sense of the word, whether by refluxing or other- I wise, is to be avoided as far as possible in' carrying out the novel process. In some embodiments of my 1nvent1on I employ steam to assist the distillation, and in that case the apparatus usedV should' include provision for supplying steam under such control as nevertheless to permit operation at the desired low pressure.

One practical form of apparatus in which the `novel process may be carried out is shown in the accompanying drawing which illustrates, more or less diagrammatlcally, a complete worklng system 1n elevation, parts vbeing in section for clearness of illustration. This system is adapted for distillation either with or Without the use of steam. 1

At is a horizontal cylindrical still internally strengthened in any suitable manner to prevent collapse. as by means of peripheral ribs 11 andl diametral braces 12;"

the peripheral ribs 11 being apertured or interrupted at the bottom of the still. as indicated at 13, in order not to obstruct Afree movement of liquid material along the bottom. Vapors from the still 10, after passing the balle 14 guarding the vapor outlet of the still, go through large vapor offtake pipe 15 to a condenser coil 16 contained in acondenser box 17, which is provided with a pipe 18 for admission of steam or other fluid heating agent to warm the coil 16 where desirable, and with an overiow pipe 19. Said baffle 14 should be positioned far enough below-the vapor outlet to ,avoid materially restricting the outflow of vapors or causing reluxing to the still. The condenser coil 16 discharges into a closed baille box or separator 20 at a point below the top thereof. said box or separator containing' a series of baiies indicated at 20a, and having a liquid discharge pipe 21 leading from the lower part thereof, and a vapor otake pipe 22 leading from the upper part thereof. The liquid discharge pipe 21 goes through La look -box 23, and thence into a manifoldlorheader 24 which. communicates by branches 25, through valves 26, with receivers 27.

Vapor ofl'take pipe 22 goes to a condenser coil 28 immersed in a cooling liquid contained in box 29, said coil 28 discharging into the receiving tank 30. having a valved draw-ofi' pipe 31 and a pipe connection 32 leading from the upper part of the tank to the main vacuum pump P1, which should be capable of maintaining a diminished pressure of as low as 1.0 or1= mm. of mercury in the entire system. Means are provided to cool the` condenser 28 and receiver 30, when these are employed, such means taking the forrn in thls instance of a refrigerating system in which cooling brine is supplied from a. suitable brine pump (not shown) through pipe 33 to coil 34 in the receiver,

and thence to coil 35 in the condenser box 29, the brine returning to the brine tank (not shown) through pipe 36. Then steam or waterlvapor is to be used in the distillation, this is furnished by a boiler' 37 provided with a bleeder valve 38, and with a vapor exit p-ipe 39 leading to a coil 40 arranged in a superheater 41, said coil 40 discharging through pipe 42 past valve 43 into the still 10. Said discharge pipe 42 extends well toward the bottom of the still and has its lower part-42l perforated for delivery of the superheated steam or water vapor in jets into the still contents.

In o rder to permit rapidly withdrawing samples of the oil distillate for test as the distillation progresses, without admitting any substantial quantity of air into the system, a sampling device is provided comprising a small closed container or chamber 44 connected to header 24 by an inflow pipe connection' 45 valved at 46, and having a discharge 47 valved at 48. Said chamber is also provided with a bleeder valve 49, opening to atmosphere. lVith valve 46 open and valves 48, 49 closed, distillate4 flows into and fills container 44. Upon closing valve 46 and opening valves 48, 49, thedistillate in the container is discharged under atmospheric pressure. The valves are then restored to their first `mentioned positions. The sampling container is of such small size as compared to the rest of the apparatus, that the quantity of air admitted into the container at each sampling is negligible as regards its eil'ect on the system or on the oil therein. It is to be, noted that admission of any substantial quantity ot air into the system vis to be guarded against, not only because of the consequent difficulty of maintaining the desired high degree of vacuum,

but also-4 because of the Aoxidizing effect on the oil. Substantial oxidation would seripor introduced into the still, the still l() is charged with oil, such as topped crude or residuum, up to approximately the level indicated in dotted lines, and the vacuum pump P1 connected with pipe 32 is started, valves 29, 32a and 32"' being open., and valves 52, 53 being closed. Heat is applied to still 10 and superheater 41. If the atmospheric temperature is sufiiciently low to require it, heat is also applied at the same time to water boiler 37 to generate Water vapor. Valve 43, which has been closed up to this time, is now openedslightly and the brine pump is started to sunn-ly brine through pipe 33 to the refrigerating coils 30 and 35 for cooling the condenser 28-29 and receiving tank 30. Steam may be run into condenser box 17 through pipe y18 in order to keep the condenser16-17-warm enough to prevent condensation of moisture and yet to ensure condensation of the oil vapors coming over from the still 10. Vater re-4 sulting from the condensation of steam in 18 overflows at 19. The admission of" steam is so controlled by valve 43 as to permit the vacuum pump P1l to maintain an absolute pressure of not more than 5 min.` mercury in the system. v

When the condensed oil and uncondensed water vapor reach the baffle box or separa.- tor 20, they separate, the water vapor passing out through the oilitakeA 22 .and thence into the cold condenser 28-29 where it con- Adenses, the resultant water collecting in relthe header 24. Thus the water and oil are collected ,entirelyv separately and thel formation of emulsions is prevented. p

When the distillation is completed, valve 43 is closedand bleeder valve 38 opened to establish atmospheric pressure in the boiler. This prevents the oil or residue siphoning back from still 10 into boiler 3".' The main vacuum pump P, is then shut down, and the bleeder vvalve 50 of the connected receiver- 27 is opened -to bring the system back to atmospherio pressure. Steam is cut of from condenser box 17 and the brine pump is shut down. Water is then drainedifromv receiving box 30 through drainpipe 31. Theli uid residue in still I10 may be runoff throng afsuitable drain pipe ,(lnotshown), the entire residue being easily removed because ofthe entire absence of coke. The operation is thus completed and the apparatus is ready for another run. l carrying out the process of the invention where water vapor' is not used'in conjunction with the high'vacuum, the baffle box. y20 and the parts in series therewith through vap'onloutlet ypipe 33 are not required, and the"intake of main vacuum pump P1v is connectedldirectly to vapor outlet 22 through pipe 51 by opening valves 52, 53, while valves 29Eand 32 are now closed. It is of course also unnecessary to employ the steam generating system, and valve 43 therefore remains closed whenl employing dry distillation. Ordinarily'it isalso unnecessary to admit steam tothe condenser tank 17 and where desirable, a cooling fluid may" even be admitted thereto through pipe 1 8.

Pipes 54, connected with an auxiliary vacuum pump P'2 through header 55, enable restoration of low pressure in either receiver 27 after Withdrawal of the condenser distillate therefrom, without disturbing the pressure in the system or admitting air thereinto. When a receiver 27. is filled, its admiion valve 26 is closed, airis admitted through bleeder valve y50, valve 57"-of discharge pipe'v 58 isl opened, and the distillate is pumped ,to storage tanks (not shown).-v

:VVhen the receiving tankis empty, valves 57 and, 50 are closed, theA auxiliary vvac-num pump P2 connected to pipe 54 is started, and

valve 56 in pipe 54 is opened; 'and when the Vdeslred reduction in pressure has been` reached, valve 56 is closedy and valve 26 is opened,the main vacuum pump Plvthereafter acting to maintain the desired degree of vacuum in the receiverk as well as in the other parts of the system. Havin outlined above the genera-l procedure t at maybe followed in employingy the described apparatus -for treating oils in accordance with the invention, typical, ex-

amples of the novel' process as applied tov distillation of different hydrocarbon materials available as starting materials will now be set forth in greater detail.

Assume that the novel process is to be applied tothe manufacture of valuable hydrocarbon lubricants from crude troleuin of naphthenic or asphalticvbase origin. So

far as concerns the removal of the lighter fractions from the crude, that is to say, re-` moval of fractions lighter than lubricating 011s, this may be effected by` any'suitable toppin method, and as such methods are in themse ves well known, generally speaking,

no detailed description thereof is necessary here. For best results, however, the stripping or topping should be conducted in such manner as to avoid cracking any of the 70 In employing the described apparatus for nected therewith, is reduced to beloivl millimeters mercury absolute pressure, and most desirably is reduced to from 1 to 1.5 millimeters. As-low a pressure as this is attainable 1n practiclng the inventlon where the oil is substantially free of moisture; and op- Aat a central point therein.

l sample is taken,

eration at 2 to l millimeters is practically always feasible. This assumes, of course, the employment of an absolutely tight apparatus system. 'The still is then. fired with fuel oil or other suitable heating medium to bring the temperature up gradually to the initial distillation teml'ierature which, in the case of a topped oil'like that assumed, is usually around 300 to 350 F.' Care is taken that the firing flame does not come in contact with the bottom of the still, thus avoiding localized overheating and consequent cracking of the oil; and the heatingr of the still is therefore accomplished by radiation, -proper provision being made to keep the flame away from actual contact with the' still itself while conveying the necessary heat units thereto. Various arrangements for'this purpose are available in the art and unnecessary to describe here. lIf the oil to be treated contains water, the still should be gradually heated up before being placed under high vacuum. Y

`Unless isdesired to obtain products of exceptionally fine color and sweet odor, as for example in the manufacture of white medicinal oils, it is not `necessary to introduce steam into the still; and it will be assumed in this example, therefore,that steam is not employed. The temperature of the oil.in the still is under observation at all times by means of a pyrometer which may be so located that the thermo-couple is within a half an;inch or so of the bottom of the still The temperature of the oil in the still may be closely 'controlled by regulation of the firing flame.

As soon as distillate begins to come over, a

and its viscosity, and'optionally also its flash and fire oints, are accurately determined. -The istillation is continued, samples being taken at suitable intervals. until the increase in viscosity indicates the necessity or desirability of cuttlirng or example, if it is desired to makev spindle oils, the tillate hows a Viscosity of 100 seconds Saybolt universal (at 100 E). The pressure -markedly in very first cut can be `made when the dis-` in the first receiver may then be released and the first cut, spindle oil, may be pumped to storage.

The procedure is substantially the same as described for the remainder of the distillation, the .pressure being maintained .at around 1 tov-1.5 mm., or at any rate below 5 mm. for`-`best results, and the distillate being cut for the desired fractions in accordance with the increase in viscosity as determined by the test-ing of samples at frequent intervals. Proceeding in this way, products aggregating from to 95 per cent of the volume of the topped crude originally charged into the still may be obtained as straight overhead distillates. The residue in the still is known to the trade as a fiux oil, usually having a gravity oflaround 12 to 14 Baum. The final distillation temperature should not ordinarily be allowed to exceed 620 Lto 630 F. as a maximum. Under these conditions, cracking or decomposition, and formation of coky products, are entirely avoided. The radical differences between the present method and those hereto- ,fore customary in the art, become especially apparent when it is b orne in lmind that in the usual methods of obtaining lubricating oils -up to viscosities of only -750 seconds (at- 100 F.), distillation. temperatures of 750 to 800 F. and higher are employed, which of course causes extensive cracking and gives dark colored oils which must be acid-treated to render them fit for use. In the present process, on the other hand, lubricating oils of viscosities as high as 150 seconds (at 212 F.) `ma be distilled over at around 575 to 600 and as high as 170 seconds (at 212 F.) at around 600 to 620 F., this latter being approximately the endpoint of the kerosene cut in ordinary disstillation at atmospheric pressure.

The various distillation products may corin the trade, that is,

under the usual grades etc., but they differ light, medium, heavy,

the products heretofore known under thosev grades. Taking these new products just as they distil over in the present process and without acid treatment or filtration, they are all superior in color to'oil's of corresponding grades heretofore available commercially.

Furthermore, as already pointed out,-they are of much narrower viscosity range, and also of better flash and fire test. It is especially emphasized again that the novel products just referredto have not been treated with acid `or filtered, notwithstanding the fact that they show the before-mention points of superiority over the corresponding grades of oil now commonly known in the trade, which latter-i invariabl :shave been treated with acid andfltered. y subjecting the products obtained in my process to important respects from ed y ' (at 212 F.

treatment with acid and filtration, a st-ill further superiority in color is'attainable. It is to be understood, of course, that the acid treatment., if employed, is lrestricted from a commercially profitable standpoint to the lighter lubricating oils obtained u to a critical viscosity beyond which acic treatment is' not feasible without dilution.

The products obtained in the described distillation range from the light and medium lubricating oils up through heavy and ext-ra heavy motor oils, and far beyond these up to vlsco'sities as high as 170 seconds Saybolt universal (at 212 F.) In this connection it is to be especially notedthat lubricating oils of above 100 seconds (at 212 F.) viscosity, obtained by overhead distillation, have been heretofore unknown and unobtainable in the art. The present process therefore makes possible, among other things, the production of a series of heavy lubricating oils that are novel in character and of the very highest utility for certain purposes where extremely heavy lubricants are required. Heretofore lubricating oils having a viscosity greater than 100 seconds have been produced solely by filtration o still bottoms after the lighter lubricating fractions have been distilled ofi'. These still bottoms or cylindelstocks. invariably contain a substantial portion of cracked products and asphaltic constituents and are Yvery dark in color. The heavy lubricating oils having a viscosity from 100 to l170 (at 212 F.)` obtained by the present process are, on the other hand, free from cracked products and asphaltic constituents, and the color of thedarkest is better than the color of the best filtered cylinder stock now obtainable which is-known to the trade l. as FFF color.

In the foregoing specific example of one way -of'carrylng out the distillation of a topped crude oil, it was assumed that the varlous desired final products were obtained directly in one distillation by cutting at the necessary intervals indicated by viscosity tests throughout the entire range of products. Another mode ofhprocedureand one which has some practical advantages, consist-s in making only two cuts 1n a first distillation of the starting material, )the first cut being made when the distillate -has attained a viscosity of about 750 seconds (at 100 F and then cutting the. remainder of the distillate into a separate receiver. The first cut therefore includes all the lubricants up to and through the heavy motor oils; while the second cut includes the extra heavy motor oils and the heaviest lubricating oils up to a viscosityV of as high as -170 seconds (at 212 F.). Suiiicient quantities of these two cuts are-accumulated to enable redistilla-tion or re-running of the cuts separately in re-run stills provided for this purpose.

The process of the invention is especially` applicable to 'the treatment of still bottoms obtained from the ordinary distillation of naphthenic base crudes. bottoms are used, the method ofdistillation is substantially as hereinabove described, but

Where such still the initial distillate is usually of a viscosity of about 70 seconds (at 212 `F.). Succeeding cuts increase 1n viscosity lup to about 170 seconds (at 212 F a-s before described.

At least to 95 per cent of the still bottomswhich material has heretofore been practically-waste material in the art, is thus obtainable as overhead distillates in the form of high grade` heavy lubricating oils of' narrow range high viscosit-ies, high flash and fire tests, free from tarry or asph'altic matter and of exceedingly good color. The darkest of these oils is ordinarily not darker than 6 N P. A. (National Petroleum Association), the N. P. A. color standard being that commonly employed in measuring color. As before stated, these high viscosityoverhead distillates are novel products in the art.

My nove-l process is also applicable to t-he treatment of topped or stripped crudes and still bottoms of p'ara-fiinic base origin, but in order to treat such starting materials commercially it is necessary to make special provision for the removal of the paraffin Wax content which comes over during the entire distillation. One method of removing par- 4affin from the distillates is by centrifuging although it is to be understood that other methods can be employed for this purpose.

In handling paraffin base crudes, the prevailing refinery practice is to distil overhead with steam up to acritical temperature at which decomposition takes place. The distillates thus obtained are freed from their paraffin content, re-distilled, acidtreated, and filtered, to produce commercial products commonly known to the trade as 200 Pennsylvania, neutral. The still bottoms v(cylinder stock) remaining are freed from amorphous waxy content and filtered to desired color, known as FF`F. In contrast to this practice, the novel process herein described makes it possible to treat the still bottoms or cylinder stock from paraffin base crudes by distilling overhead without decomposition and obtaining- 60 per cent of the material in distillatesy rang- Prior ons. Schulze narrpw cu Na h- Paran P mph' thene base. base. gli? Light oil.

Gravit Baume 30. 0 21.0 21. 0 Flash F.) 405 320 360 Flash range F.) 290 to 550 250 to 460 340 to 380 Viscosity at 100 F. Saybolt universal (sec.)... 190 200 200 Viscosity range (sec 60 to 600 60 to 2,000 100 to 300 Color N. P. A.... 25 Pour test (A. S. T. M.) F.). 30 Below zero. Below zero. Initial boiling point at 1.5

mm. F.) 374 320 400 Percent distilled over up to 450 F. (1.5 mm.) 10% 60% 98% Medium oil.

Gravit Baume 29. 0 20. 5 20. 5 Flash F. 425 33o ssc Flash range (I FJ.. 300 to 550 255 to 480 370 to 430 Viscosity at 100 F universal (sec.).... 260 300 300 Viscosity range (sec.).. 'l0 to 1,400 60 to 2,200 300 to 50 or lN. P. A 3l 2 Pour test (A. S. T. M.) F.). 35 Below zero. Below zero. Initial boiling point at 1.5

mm. F.) 410 350 435 Per cent distilled over up to 475 F. (1.5mm.)............ 22% 46% 98% Heavy oil. Gravlt Baume 28. 5 19. 5 19. 5 FlashSLF.)...... 435 360 100 Flash range F.) 305 to 550 260 to 510 385 to 450 Viscosity at 100 F. Saybolt universal (sec.) 365 500 500 Viscosity range (sec.).. to 1,000 70 to 2,400 400 to 700 Color N. P. A 5 Pour test (A. S. T. M.) F.). 35 Below zero. Below zero. Initll boiling point at 1.5

mm. F.) 437 390 440 Per cent distilled over up to incarne 212' F), 030 F. flash ltest and 700 F. lire test, and is alsoa novel product. rl`his is an example of how the new process may be applied'toythe manufacture, from paraiiin-base oils, of high viscosity lubricants by straight overhead distillation, and of a novel cylinder stock. l

In order to afford a definite comparison between typical novel products obtainable.

in accordance with the invention, on the one hand, end 'products of approximately corresponding1 commercial grades 'of oils here tofore available on the other, a table is given below in which the principal test characteristics of light, medium and heavy motor oils produced from a naphthene base crude in accordance with the present invention are compared with those of the corresponding three commercial grades of well known paraflin base and naphthene base motor oils,

the prior oils selected for this comparison representing the best quality obtainable on .the market. The figures given are the resultsof 'actual laboratory tests.

The foregoing tableI is self-explanatory; but it may be noted' in connection with the ligures given for the per cent of sample distilled over upto the maximum distillation temperature mentioned, that the figure of 08% iorthe new oils signifies that substantially'fthe entiix'eA sample distilled over, the deiicitof 2% representing the unavoidable mechanical loss oi oil in handling the sample in conducting the test. lt is also to be understood that the figures for ilash range and viscosity range represent the flash points and viscosities of the iirst and last 10% fractions, respectively, obtained by distilling a sample of the oil at a pressure of 1.5 mm. mercury absolute.

Asiurther examples oi 'the novel type oi lubricating oils obtainableein the practice ci the invention, identifying characteristcs of live typical heavy narrow cut lubricating oils are also given below, all distillation data having been obtained in operation in a com- `mercial still at 1.5 mm. mercury absolute process without ire-running.

No. l. No. 2. No. 3. No. 4. ,No. 5.

Gmvlt B.) 18. 2 i8. 0 17. 5 17. 0 riashd.)..... 455 47o an 52o Flash range (F. stili-.470 4801-500 500-540 Fire (F.) 545 560 575 600 Viscosity of sample Saybolt sec. at 21 E). 70 85 100 125 150 Viscos?t renie -80 00-110 110440 140-170 Color( .1. l 5 5i: 6 S; .Pour test (A. S. T. hi). 5 5 5 l0 l5 initial B. l". ("F.) 475 490 '20 550 575 All distilled over at (F.) 4520 520 550 575 p 590 ln general, lubricating oils manufactured in accordance with m invention are most readily distinguishable from comparable prior oils b comparison of their respective 'ranges of viscosity and distillation temperatures or boiling points, and ci the relative proportions distilling over up to a given teniperature. rl`he new oils are all characterized by narrow viscosity ranges that are 'ar narrower than those found in prior available oils. @ils of the novel type herein decribed, having viscosities up to 150 seconds Saybolt universal at 100o F., show viscosity ranges as low as 50 seconds; while a range oi' 100 seconds is common, and a range oi 250 seconds is approximately the maximum for oils oi this particular class. The novel'oils having viscosities ci' 150 seconds (at F.) and upwards are characterized by viscosity ran es as low as 20 or 30 seconds (at 212 F.) or the very heavy oils; and by typical limiting viscosity ranges ci 250, 5,00, and 700 seconds (at 100O F.) for commercial grades of lighter oils of this novel f' onds or distillation range at 5mm. mercury presclass. lt is well known that such narrow ranges of viscosity are not approached-byv vv comparable oils heretofore known.

Similaw ly, light oils are readily obtainableby ymy rocess having viscositiesof 200 sec- (Izit 100 or less but whose boiling sure or below is not over 50 F. in some instances; andflimiting ranges of F. and 100 F. are typical in other cases. In the case of heavy oils having viscosities upward of 70 Aseconds (at 212 YF.), a distillation range as small as 50 F. is also characteristie o f. narrow cut Oils obtainable by my process.-

Further classification of oils manufactured in accordance with the invention may bel made-as follows, the data given 'being based on results obtained in operating commercially on naiphthene base crudes and still bottoms.

Flash Fire point point Viscosity range Viscosity (seconds). not less not less (seconds) (5 min.

than than distillation.)

UF.) Us).

280 340 50-200 (100 F.). 310- 370 125-300 (100 E). 320 380 Z50-400 (100 F.). 340 400 300-700 (100 E). 380 44.0 500-1000 (100 F.). 390 450 50-120 (212 F.). 440 500 90-175 (212 F.).

Another characteristic distinguishingjthe present novel straight overhead non-acidtreated lubricating distillates from lubricating oils heretofore available commercially, practically all of which latter having viscosities up to 750 seconds (at 100 F.) are acid treated, is the fact that the oils of the present invention show little or no tendency to form emulsions withwater when'subjected to severe'emulsifying tests, but on the contrary separate from water quickly and clearly. Commercial oils heretofore available, on the other hand, invariablyg'emulsify with water to a substantial extentand oftenemulsify excessively. This is due to the practical impossibility'of removing all traces of lthe com lex alka-li-'sulfonic'acid compounds versal (at 100 E), "and further character'- ized by the fact that when a sample of said' oil is substantially' completely distilled under an absolute pressure' of 5 mm. mercury or lessand under non-oxidizing conditions,

ten per cent fraction'ofthedistillate ditl'er in viscosity by not more than'5250`seconds -Saybolt universal .(at 100 F 2. As afnew 'article of manufacture, a mineral lubricating il having a. viscosity not exceeding about 150 seconds Saybolt universal (at 100 F.), and further characterized by the fact that when a sam le of said oil is substantially completely di an absolute pressure'of 5 mm. mercury or less and under non-oxidizing conditions, the first ten per cent fraction and the last' ten per cent fraction of the distillate differ in viscosity by not more than 100 seconds Saybolt universal (at 100 F 3. Asa new article of manufacture, a mineral lubricating oil having a viscosity not exceeding about 150 seconds Saybolt universal (at 100 F and further characterized by the fact that whena `sample of said oil is substantially completely distilled unl der an absolute pressure of' 5 mm. mercury or less and under non-oxidizing conditions, the first ten er cent fraction and the' last ten percent fraction of the distillate differ in viscosity by not more than 50 seconds Saybolt universal (at 100ov 4. As anew article of manufacture, a minveral lubricating oil having a viscosity of 200 seconds or less, Saybolt universal (at 100 F.), which .oil distils substantially completely under non-oxidizing conditions at or below 5 mm. mercury absolute pressure between initial and final boiling points differing by not more than 100 F.

5. -As a new articleof manufacture, a minera-l lubricating oil having a viscosity of 200 `seconds or less, Saybolt universal (at 100 F), which oil distils substantially completely under non-oxidizing conditions at or below 5 mm. mercury absolute pressure between initialand final boiling points differ-- ing b not more than 7 5 F.

6. i' s a new articleof manufacture, a min-- below 5 mm. mercury absolute pressure between initial and final boiling points diifering by not more than 50 F.

stilled under` .the first ten 'per cent fraction and the last 7 As a new-article of manufacture, a mineral lubricating oil having a viscosity of at least 150 seconds Saybolt universal (at 100 lao nieuwe 8. Asl a n'eyv article of manufacture, a mineral lubricating oil having a viscosity of at least 150 seconds Saybol't universal (at 100 and further characterised by the' fact that whenfa sample of said oil is substan-` tially completely distilled under an absolute' pressure of 5 mm. mercury or less and under non-oxidizing conditions, the irstten per cent fraction and the last ten per cent fraction of the distillate differ-vin viscosity by not more than 500 seconds Saybolt universal (at,100'-F.).

9. As a new article of manufacture, a mineral lubricating oil having a viscosity of .at

- versal (at 100 F.)

10. As a new article of manufacture, a mineral lubricating oil having a viscosity of 150 seconds or greater, Saybolt universal (at 100 E), whichoil distils substantially completely under nonoxidizing conditions-at or below 5 mm. mercury absolute pressure between initial and final boiling points differing by not more than F.

11. As a new articleof manufacture, a mineral oil whose viscosity..^is150 seconds or greater, SayboltjuniversalV (at 100 E),

vand which distils 'substantially completely under non-oxidizing conditions at or below 5 mm. mercuryabsolute pressure between boiling' points differing by not more than 100 F. f

12. As a new. article of manufacture, a mineral oil whose viscosity is 150seconds or greater, Saybolt universal (at 100 E), and which distils substantially completely under non-oxidizing conditions at or below 5 mm. mercury absolute pressure between boiling points differing by lnot morel than y'i 5 F.

new article of manufacture, ai

13. As a I straight overhead lubricating oil distillate derived from a naphthenic base oil and havmg Saybolt universal (at 212 F.) said distillate being substantially free-o tarry matter.

derived from a naphthenic base oil andlhaving a viscosity exceeding 100 seconds, Saybolt universal (at212-), said distillate being substantially free ,of tarry matter.

15. As a new arti'cleof manufacture, a straight overhead lubricating oildistillate derived from a naphthenic base oil, and having a viscosity 'exceeding 150 seconds a viscosity of not less'than90 seconds" 14.. As a new article of manufacture, a.- straight overhead lubricating oil distillate" `daybolt universal (at 212 E), said distillate being substantially free of tarry matter.

,16.As a new article of manufacture, a straight overiead lubricating oil distillate derififed from a na'phthenic base oil and having a viscosity of about 17 0 seconds Saybolt universal (at 212 E), said distillate being substantially free of tarry matter.

17. As a new article of manufacture, a mineral lubricating oil having a viscosity of atfle'sast- 0 seconds Saybolt universal (at 21,2.F.), and further characterized by the fact that when a sample of said oil is substantially completely distilled under an absolute pressure of '5 mm. mercury or less and under non-oxidizing conditions, the first ten per cent fraction and the last ten per cent fraction of'the distillate differ in viscosityv by not more than 30 seconds Saybolt universal (at 212 E).

18. As a new article of manufacture, a mineral lubricating oil having `viscosity of at least seconds Saybolt universal (at 212 F), and further characterized by the fact that when a sample of said oil is substantially completely distilled under an absolute pressure of 5 mm. mercury or less and under non-oxidizing conditions, the first ten per cent fraction and the last ten per cent fraction of the distillate dider in viscosity by not more than 2 0 seconds Saybolt universal (at 212 F 19. As a new article of manufacture, a lubricating oil whose viscosity is 70 seconds 'or greater, daybolt universal (at 212 F), and which distils substantially completelyy under non-oxidizing conditions at or below 5 mm. mercury absolute pressure between initial and final boiling points dilfering by not more than 50 F.

20. As a new article of manufacture, a mineral lubricating oil having a viscosity of not more than about 150 seconds Saybolt universal (at 100 E), a flash point of not less than 280 F., and a re point of not less than 340 F., said oil yielding no fraction. upon distillation under non-oxidizing conditions at 5mm. mercury or less absolute pressure, having a viscosity of less than 50 seconds or greater than 200 seconds, Saybo'lt universal (at 100 21. As a new article of mineral lubricating oil having a viscosity lying'between about-150 seconds and about 250 seconds, Saybolt universalv (at 100 El a flash point of not less than 310 F., and a fire ointv ofl not lless than 370 F., said oil' yie ding no fraction, upon distillation under non-oxidizing conditions at 5 mm'. mercury or less absolute pressure, having a viscosity of less than 125 seconds or greater ythan 300 seconds, Saybolt universal (at 22. As a usw article of manufacture, e

manufacture, a

` flash point of not less than 390 vmineral lubricating oil having.. a viscosity lying between about 250 seconds and about 350 seconds Saybolt universal (at 100 F.), a ash point of not less than 320o F., and a fire point of not less than 380 F., said oil yielding no fraction, upon distillation under 'non-oxidizing conditions at 5 mm, mercury or` less absolute pressure, having a viscosity of less than 250 seconds` or greater than 3B4;;0 seconds, Saybolt universal (at 100 23. As a new article of manufacture, a mineral lubricating oil having a viscosity lying between about 350 seconds and about 550 seconds, Saybolt universal (at 100 F.), a. flash pointof not less than 340 F., and a re point of notiess than 400 F., said oil yielding no fraction, "upon distillation under non-oxidizing condit1ons at 5 mm. mercury or less absolute pressure, having a viscosity of less than 300 seconds or greater than 700 seconds, Saybolt universal (at 100 E).

24. As a-new article of manufacture, a mineral lubricating oil having a viscosity lying between about 550 seconds and about 900 seconds, Saybolt universal (at 100 F.), a flash point of not less than 380 F., and a fire point of not less than 440 F., said oil yielding no fraction, upon vdistillation under non-oxidizing conditions at 5 mm. mercury or less absolute pressure, having a viscosity of less than 500 seconds or greater than 1,000 seconds, Saybolt universal (at 100 F 25..As a new article of manufacture, a mineral lubricating oil having a viscosityl lying between vabout 60 seconds and about 100 F a F., and a fire point of notvless than 450 F., said oil yielding no fraction, upon distillation under non-oxidizing conditions at 5 mm. mercury or less absolute pressure, having a vviscosit of less than 50 seconds or greater than 120 seconds, Saybolt universal (at 212o F.)

As a new article of manufacture, a mineral lubricating oil having a viscosit lying between about 100 seconds and abouI 150 seconds, Saybolt universal (at 212 F.), a liash point of not less than 440 F., and a fire point of not less than 500 F., said oil yieldin no fraction, upon distillation under non-oxi izing conditions at 5 mm. mercury or less absolute pressure, having a viscosity of less than 90 seconds or eater than 175 seconds, Saybolt universal at 212 F.).

27. The process of producing useful mineral oil distillates which comprises ling, under an absolute pressure not exceeding 25 millimetersmercury, mineral oil material containing substantially' no constitu ents as volatile as gasoline.

28. The process of producin vuseful mineral oil distillates which comprises distilling mineral oil materialunder an absolute presseconds, Saybolt universal (at 212 distilf retenes 'meters mercury.

30. 'The -process of producinl useful fmineral oil distillates which compr1ses distllling with the aid of water vapor mineral oil ma- `terial containing substantially no constituents as volatile as gasoline, While maintaining a distillation ally above 25 millimeters mercury absolute and restricting the distillation temperatures to below about 620 to 630 F. ,l

31. The process as set forth in claim 30, in which the pressure is from cury absolute. v

32. The process of .manufacturing mineral oil lubricants which comprisesl subjecting mineral oil material containing substantially no constituents as volatile as gasoline to distillation under an absolute pres'- sure not substantially exceeding Q5 mm. mercury and cutting the distillate between predetermined vlimits of viscosity.

33. The process of manufacturing mineral oil lubricants which comprises subjecting mineral oil from which lighter products have been removed to distillation under an absolute pressure not lsubstantially exceeding 5 mm. mercury, and cutting the distillate l between predeterminedv limits of viscosity.

34. The process of manufacturing mineral oil lubricants which comprises subjecting mineral oil from which lighter products have been removed to distillation under an absolute pressure of between 1 and 5 mm. 4mercury and cutting the distillate between predetermined limits of viscosity.

35. The process of producing mineral oil y lubricants, which comprises fractionally distilling under an absolute pressure'not substantially exceeding 5 mm. mercury mineral oil containing substantially no fractions of a viscosity 'lower than 50 seconds Saybolt universal (at 100 F and'condensing the vdistillate under substantially the pressure of distillation. v

36. The process of producing mineral oil lubricants, which comprises fractionally distilling under an absolute pressure not substantially exceeding 5 nun. mercury a stripped crude oil, and condensing thedistillate under, substantially the pressure of distillation.

37. The process as setv forth in claim 36,

pressure'y of not 4substanti- 1 to 5 mm. merv in which the pressure employed does not substantially exceed 1.5 mm. mercury absolute. I

38: The process of producing mineral oil lubricants, which comprises fractionally distilling under an absolute pressure not substantially exceeding 5 mm. mercury still bottoms derivedvfrom distillation 'of crude petroleum, and condensing the distillate under substantially the pressure of distillation.

39. The. process as set forth in claim 38,

in which the pressure employed doesnot substantia'l-ly exceed 1.5 mm. mercury absolute.

40. The process of manufacturing mineral lubricating oils by overhead distillation Without. acid treatment or filtration, which comprises subjecting lubricant-containing mineral oil to distillation under pressure not Yexceeding 5 mm. mercury absolute while avoiding substantial refluxing of the distillate, and conducting off and condensing lubricating oil distillate at substantially the same 42. The process of manufacturing mineral lubricating oils which comprises subjecting mineral oil, such as crude oil or still bottoms of naphthenic base origin to distillation under pressure not exceeding 5 mm. mercury absolute While avoiding substantial reiuxing of the distillate, controlling the distillation temperature to prevent its going above 620 F. to 630 F., obtaining overhead lubricating cuts, the distillation being continued until at least 60 per cent of the original charge has distilled over.

43. The process as set forth in claim 42, in which lubricating cuts having viscosities up to as high as 15() seconds Saybolt universal (at 212 F.) are distilled-over.

44. The process of manufacturing mineral lubricating oils which comprises distilling mineral oil with the aid of `steam introduced thereinto, maintaining thefpressure in the distilling chamber at or below about 5 mm. mercury absolute, increasing the distillation temperature to a maximum not exceeding about 620045300 F., and collecting heavy lubricating oil as overhead distillate.

45. In the manufacture of lubricating oils, the process which comprises distilling a lubricant-containing mineral oil material at an absolute pressure not' substantially exceeding 15 mm. of mercury and under non-oxidizing conditions.

46. In the manufacture of lubricating oils,

the process which comprises distilling a lubricant-containing mineral oil material at an absolute pressure not substantially exceeding 10 mm. of mercury and under nonoxidizing conditions. y

47. In' the manufacture of lubricating oils, the process Which comprises distilling a lubricant-containing mineral oilmaterial at an absolute pressure of between 1 and 5 mm. of mercury and under non-'oxidizing conditions. f

48. The process of manufacturing mineral lubricating oils by overhead distillation 'Without acid treatment or filtration, which comsignature.

JOHN E. SCHULZE.

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