US1936657A - Treating oil - Google Patents

Description

0. BEHIMER Nov. '28, 1933.

TREATING OIL Filed Jan. '17, 1922 2 Sheets-Sheet 1 IN VEIyZR A TTORNFV Nov. 28, 1933. 0. BEHIMER 1,936,657

TREATING OIL Filed Jan. 17, 1922 ,Sheets-Sheet 2 .IIIIIIIIIIIA r A N N w \1 1 w IN VENTOR HIS A TTORNE Y Patented Nov. 28 1933 TES v UNITED TENT FFlCE TREATING 01L Application January 17, 1922. Serial No. 529,905 25 Claims. (a. ice-17) This invention relates to improvements in processes of distilling hydrocarbon oils and contemplates a method of operation by which a maximum yield of distillate may be obtained with a minimum amount of decomposition and carbonizing in the still.

In accordance with my invention the oil to be treated is forced through a coil or heating zone of comparatively restricted cross section so that heat may be readily transmitted into the flowing oil. The oil while it is being heated is held under a superatmospheric pressure sufficient to main=- passage of the oil through the coil is preferably carbons is avoided. The oil having been brought -so regulated that decomposition of the hydroto the desired temperature is then passed into a separator or distillatory chamber wherein the pressure is reduced so that the liberation of vapor may take place. J

My invention is particularly adapted for the distillation of the heavy residues of petroleum. As is known, such heavy residues of petroleum comprise lubricating oil fractions, including cylinder stock fractions, as well as asphaltic constituents suitable for asphalt production depending, of course, upon the source of the crude. In prior methods of distillation it has been difilcult to distill a major fraction from the more heavy petroleum residues since it has been impossible to apply to the oil'the necessary heat for the distillation without thereby subjecting portions of the oil to overheating and causing decomposition of the oil, resulting in the deposition of carbon on the metal surfaces of the still and a consequent carbonizing and deterioration of the metal. "-.In accordance with my invention these heavy residual oils, regardless of their composition or character, may be readily distilled to yield as high as 80% or 90% distillate without substantial decomposition of the oil'or carbonizing of metal surfaces.

Considerable dimculty has hitherto been experienced in the .proper disposal of pressure still residues resulting from the decomposition of hydrocarbon oils. These residues generally contain considerable portions of free carbon and asphaltic and polymerized constituents which in prior methods of distillation have caused trouble. It has in fact been hitherto impossible todistill'off from such residues major fractions, since when the necessary heat for such a distillation was applied to these oils the resulting decomposition. and carbonizing was so great as to preclude the carrying on of such a process on a practical scale.

In accordance with my invention these pressure still residues may be readily distilled to yield a distillate comprising 80 %-or 90% or even higher portions of distillate, the operation being carried on in such a manner that there is no material molecular decomposition, the constituents as derived from the cracking stills being separated into a distillate and a fiowable residue.

It is often desirable to so treat cracking still residues that a large quantity of distillate suitable for rerunning in the cracking stills may be produced. It is therefore necessary. to eflect a separation of the free carbon, asphaltic constituents and polymers from the distillate to be recharged into the cracking stills, sinceoil containing large quantities of free carbon causes dimculty when placed in the cracking stills and since the polymers break down very readily, yleld- 30 ing largely free carbon and gas, and thereby causing considerable carbonizing in the cracking stills. I have found that practically all of the free carbon may be removed by settling or by filtering but prior to my invention there has been no means of removing the asphaltic and polymerized constituents, since when suflicient heat was appliedto distill off any substantial fraction of distillate the asphaltic constituents and polymers would be decomposed causing the formation of carbon and heavy products that produced carbonization in the distilling vessel.

I- have discovered that the carbon forming polymers in these cracking residues are in the main relatively high boiling constituents and that if the residue be carefully heated under pressure, care being taken not to prolong the heating unduly, and the pressure released after suflicient heat has been thus applied to the oil, the residue may be readily distilled to yield maximum quantities of distillate of a character suitable for rerunning in the cracking stills and a comparatively small residue composed of most of the asphaltic and polymerized bodies. The residue thus produced may be freely drawn olffrom the still and is adapted for road oil, fuel oil, asphalt and other products.

The invention is also adapted for the dehydration of oils. which in prior methods of treatment have been Refractory petroleum emulsionsdiificult to separate into their oil and water com-' ponents may by my process be readily broken up.

- periods of time without any stoppage for making repairs. This is largely due to the fact that deterioration of the metal is avoided since the process is carried on in such a manner that there is practically no carbonizing of the metal.

Another advantage is that it is not necessary to use steam or other mechanical carrier to remove the generated vapors, since when the pressure is relieved, the lighter vapors present serve as a mechanical carrier of the heavier vapors and the vapors are thus freely liberated from the distilling chamber.

Other objects and advantages of my invention will become apparent from the following detailed description thereof, reference being had to the figures of the accompanying drawings. Fig. 1 is a diagrammatic elevation, partially in section,

showing an apparatus adapted for carrying out the invention. Fig. 2 illustrates a series of separators or fractional condensers.

'In the apparatus shown in Fig. 1 a pump 1 is arranged to draw the oil to be treated from a suitable source of supply. The pump has an outlet line 2 having a valve 3. The outlet orcharging line 2 preferably extends to a heat exchanger 4 which is provided with an outlet line 5 for removing the oil charged thereto by the pump 1. The pipe 5 terminates in a heating coil 6 which is arranged to be heated in any suitable manner, as by being mounted in a furnace 7 having a burner 8'and flue 9.

The heating coil 6 has an outlet line 10 which is equipped with a pressure relief valve 11. The pipe 10 discharges into a distillatory chamber or separator 12 which-is preferably constructed of ample volume that the required expansion and liberation of vapors may take place therein.

The separator may be provided with a plurality of bafiles such as the bafiles 13 which are shown positioned in the upper part of the chamber. These 'bafiles serve to break up the mist particles of heavy oils carried over by the vapors and to provide a more or less tortuous course for the vapors in order to prevent condensed particles from passing out of the separator. The separator is preferably-insulated to reduce loss of heat by radiation, or a slight or moderate heat may be applied thereto by a burner or other suitable means. Thus, as shown'in Fig. 2 the a lower portion of the'separator 12 may be surrounded by a furnace chamber 12a, provided with a burner 12b.

Suitable scrapers or agitating mechanism may be provided in the distillatory chamber if desiged. As illustrated, a number of stirring arms 14 carried by a shaft 15 are positioned in the lower portion of the chamber where the residue is collected. A stirring or agitating means of prevents any clogging of the outlets from the di stillatory chamber. It is to be understoo from the chamber 19 through the lower portion however, that in many cases no scrapers or agitators of any kind. are required.

A vapor line 16 is arranged to remove the vapors from the separator 12 to suitable means for condensing the vapors. As illustrated, the vapor line 16 terminates in the heat exchanger 4 which is preferably in the form of a cylindrical body divided longitudinally by a baflie 17 and vertically by a partition 18'. The partition 18 divides the exchanger into a comparatively large compartment 21 and an adjacent smaller compartment which is divided by the longitudinal baffle 17 into a lower chamber 19 and. an upper chamber 20, the pipe 2-entering the lower chamber 19 and the pipe 5 extending from the upper 9 chamber 20. The partition 18 is provided with a plurality of perforations communicating with which are pipes 22 which extend longitudinally of the exchanger 4 and serve to conduct liquid of the chamber 21 and thence around the end of the baffle 17 and back through the upper portion of the chamber 21 to the compartment 20. The vapor line 16 communicates with the chamber 21 and thus the vapors are caused to pass whereby the charge is'heated and the vapors are cooled. If desired, the baflie 17 may have a slight downward incline in order that any condensate collected thereon may readily pass into the lower portion of the chamber 21.

An outlet pipe 28 conveys the products from the chamber 21 to a condensing coil 24 positioned in the condenser box 25. The condenser outlet 26 conducts the liquid to a receiving tank 27. A vacuum pump 42 having a connection 43 to the receiving tank 27 may be provided, if desired.

The distillatory chamber 12 is equipped with suitable draw-off lines to remove the residue 001- lected therein. Since the process is carried on continuously, it is advantageous to have automatic means for withdrawing residue from the separator 12 and maintaining a given liquid level therein. As illustrated, a float chamber 28 is provided for this purpose, and is connected by a pipe 29 to the separator'12 so that liquid in the separator may readily flow into said chamber.

A pipe 30 extends from the upper portion of the float chamber and communicates with the vapor space of the separator 12 in order that both chambers'may be under the same pressure so that a liquid level may be maintained in the float chamber corresponding to the level in the separator 12.

An outlet pipe 31 having a valve 32 extends from the bottom of the separator to a receiving tank 33, and a line 34 having valves 35, 36, and 37 communicates with the outlet line 31 to bypass the valve 32. The valve 36 is controlled by means of a float 38 positioned within the cham-- ber 28, the float being arranged to operate a valve stem 39 of the valve 36. Thechamber 12 may be provided with a visual gage 40 to serve as a check on the operation of the float con- 'trol mechanism. If desired, the float control a superatmospheric pressure 01! such degree that a sufiicient quantity of oil remains in the liquid state to form a freely flowable fluid, thereby avoiding liability of overheating heavy carbonaceous residues or of overheating the vapors and thus preventing the deposition of carbon and the resulting deterioration of the heating coil. The rate of fiow through the coil 6 is preferably so regulated that there is substantially no decomposition in the coil. The temperature to which the oil is heated depends upon the particular object in view. For example, a lower temperature may be used when the object is to dehydrate a petroleum emulsion than when the purpose is to obtain a maximum yield of distillate from agiven petroleum residue. The oil may be heated to temperatures approaching that sufficient for decomposition or even higher but the flow of oil through the coil may be so regulated that the oil is not subjected to a cracking temperature for a sufficient time to cause any material decomposition.

Until operating conditions have been established the oil may be pumped through the coil 6 into the separator 12 and oil drawn ofi from the separator and returned to the source of the charge or to the pump 1. The circulation may be continued until operating conditions have been established when the resultant residue in the separator 12 may be withdrawn to the receiving tank 33. With temperature conditions established the oil in the coil is under superatmospheric pressure of the generated vapors and as it is released into the separator through the conduit 10 the pressure is reduced in the separator by means of the valve,l1 to approximately atmospheric pressure. If desired a slight pressure above atmospheric may be held in the separator in order to facilitate the flow of vapors and residue therefrom, or in some instances, the vacuum pump 42 may be employed to remove the vapors and a. pump provided to withdraw residue from the separator. The oil having been heated under pressure in the coil and the pressure having been dropped in the separator, there is a copious liberation of vapors in the separator. The vapors pass out from the distilling chamber 12 through the vapor line 16 and, if desired, enter the heat exchanger 4 by which the oil charge is preheated and by which the vapors are cooled to a certain extent. The vapors and any condensate collected are then passed into the condenser 24 wherein the condensable bodies are liquefied, the resulting products being collected in the receiver 27.

The liquid collecting in the separator 12 is continuously or intermittently, as may be desired, drawn off into the receiving tank 33. Preferably a given level is constantly maintained in the separator 12 by the float controlled mechanism described or by other equivalent means. Preferably a comparatively small quantity of liquid is held in the separatoronly suflicient to have a liquid level therein to enable the proper withdrawal of residue, thus affording ample space therein for the liberation of comparatively large portions of vapor.

When it is desired to use the process in treating cracked residues from pressure stills suitable settling tanks or filters are preferably provided. Thus the residue from the cracking stillsmay be removed to tanks and the free carbon allowed to settle out or the residue may be passed through filters before being charged into the coil 6 by the while in transit through the coil.

pump 1. If desired, a filter 41 may be interposed in the charging line 2.

In order to more fully set forth my invention I will now proceed to give one illustrative example thereof. In this selected example of the invention it was desired to treat a pressure still residue derived from the pyrogenic decomposition of hydrocarbon oils, in order to separate the polymerized and asphaltic products which, as heretofore pointed out, are not suitable for rerunning in pressure stills, and to produce a distillate capable of being redistilled under pressure for the production of gasoline or other similar products.

Pressure still residue having a mean boiling point of 595 F. was charged into the coil 6 by means of the pump 1. The temperature of the oil charge was slightly above atmospheric temperature and it was preheated in the exchanger 4 to approximately 400 F. The preheated oil in coursing through the heating coil was progressively raised in temperature and emergedirom the outlet 10 at approximately 800 F. The rate of flow of oil through the coil was such that it reached a cracking temperature near the end of the coil and was actually subjected to cracking temperatures for only a fraction of a minute An average pressure of 106 pounds was maintained on the coil during the run.

Experiments have proven that it is impossible to effect any material decomposition of hydrocarbons under the pressures and temperatures described as obtaining in this run, when the oil is only subjected to the stated conditions for as short a period of time as a fraction of a minute. It is clear therefore, that'no substantial cracking could have occurred in the coil. Moreover, tests of samples of oil drawn from theoutlet 10 showed conclusively that no appreciable cracking occurred, since there was no lowering of the flash point or lowering of the initial boiling point or any other indication to show that a decomposition into light products had taken place.

As a result of considerable experiment the approximate time required under varying conditions to crack hydrocarbon oils has been deter mined. It is thus a simple matter to heat the oil in the coil 6 under a superatmospheric pressure and under what may be termed cracking temperatures (since if these temperatures be maintained for a sufiicient time cracking will occur), but to so control the flow of oil through the coil that it is discharged into the outlet 10 without any material'cracking having occurred. It may be stated that at pressures around 150 pounds and a temperature of 800 Ffcracking is ordinarily carried on in a coil at the rate of approximately 0.1%. of the charge per minute. As the temperature is increased the time required for cracking decreases. b

The oil was discha'ged from the coil through the outlet 10 and control valve 11 into the separator 12 wherein a gage pressure of approximately 11 pounds was maintained, this slight pressure serving to insure that the products collected in the separator would readily flow into the vapor line 16 and into the tar line 31. The temperature in the separator 12 was approximately 50 degrees lower than that of the coil outlet and under this temperature about 90% of the oil was vaporized, the vapors passing out through the vapor line 16 and beingultimately collected in the receiver 2'7. This distillate was free from the carbon-forming polymers and asphaltic materials iao and was suitable for rerunning in the pressure specific example of the invention, wherein specific statements are made as to temperatures and pressures, and other operating conditions, I do not intend thereby to limit the invention to a method of operation involving any of these specific conditions. The run in question has been given as an example merelyand, as will readily be understood by those skilled in the art, the various operating conditions and factors may be varied Within wide limits within the scope of the invention.

When treating an ordinary pressure still residue for the production of a distillate suitable for rerunning in the pressure stills temperatures of approximately 700 F. to 900 F. and pressures around 160 to 200 pounds are to be recommended, the rate of flow through the coil being, of course, so regulated that thereis no substantial decomposition in the oil. I

When it is desired to employ the invention for stripping crude oil, or derivatives thereof, of certain fractions, the temperature is so regulated that the desired fraction or fractions may be removed as a vapor from the separator 12, a sufiicient pressure being maintained in the coil 6 to hold enough oil therein in the liquid form to maintain a freely flowab le mixture and prevent carbonization. v When it is desired to dehydrate petroleum emulsions, it is not necessary to use temperatures as high as the cracking temperatures mentioned above, since the emulsions may be dehydrated by heating in the coil under any desired pressure, for example, 100 to 200 pounds, at temperatures of approximately the boiling point of water or somewhat lower and upward to 500 or 600 F. The generated water vapor passes out from the separator 12 through the vapor line 16 and the dehydrated oil is withdrawn through the outlet 31. If desired, condensates may also be taken off with the water from the separator 12, the oil and water being collected and separated in mannerswell known in the art.

'When hydrocarbon oils are subjected to pyrogenic decomposition, not only are light volatile bodies produced but heavy asphaltic and polymerized constituents and free carbon are formed,

i producing a residue that is ordinarily heavier than water. When this residue is allowedto stand for a time, the bulkof the free carbon settles out. The free carbon may also be removed by filtering. When the residue from which the free carbon has been removed is heated under superatmospheric pressure and under temperatures, such as around 750 F.-.850 F., but with a careful regulation of the time factor so as not to expose the oil to this heat and pressure for a time long enough for material decomposition, and the pressure is then reduced to approximately atmospheric, a free liberation of vapor occurs leaving a residue composed largely of asphaltiobodies and polymers-the components of asphalt. This asphalt may be used without further treatment for asphalt purposes or it may be oxidized by air or steam blowing to vary its characteristics.

It is to be understood that the pressure in the separator 12 is maintained considerably lower than the pressure in the heating coil 6, and that sure then being released in the separator 12 and the liberation of vapors effected under a vacuum. The vapors thus liberated will comprise both low boiling and relatively higher boiling fractions. By means of the rapid heating under pressure in the coil and the liberation of vapor under a vacuum in the separator, lubricating oil fractions may be distilled 011. without the use of steam, which hasheretofore been considered essential in the distillation of lubricating oil. The use of the vacuum in the separator reducesthe temperature required in the system. Moreover, the comparatively short time to which the oil is subjected to the heat in the coil makes it possible to carry on the distillation without impairing the color of I the distillates.

Instead of employing a single condenser and condensate receiver, as shown in the drawings, the vapors may be passed to a plurality of condensers and fractionally condensed so as to produce from the generated vapors products of varying boiling'points. If desired, a series of separators in which the latent heat of vaporization and excess heat of the distillates may be used for the redistilling of the several condensates in order to carry on an efficient fractionation.

Thus, as shown in Fig. 2, the vapor leaving the evaporating chamber 12 through'the pipe 16 is conducted to a fractional separator 44a, wherein the higher boiling constituents are condensed,

and may be withdrawn through a cooling coil 48 The uncondensed vapor is pipe 45 to a subsequent separator 44b, wherein a further fraction may be condensed and withdrawn through a cooling coil 49. The extent of fractionation or condensation in the separators 44a and 44b may be controlled by supplying cooling to the reflux coils in the upper portion of each separator as indicated.

The uncondensed vapors remaining in the last separator 4422, may then be withdrawn through a pipe 46 and cooling coil 47, wherein they are condensed and the resulting condensate then drawn off through pipe 50 to a The receiver 51 communicates with a vacuum pump 53 by which means a maintainedwithin the evaporating chamber 12 ina manner similar to that described inconnection with Fig. 1.

drawn oil" through a closed receiver 51.

vacuum may be' Obviously'many modifications and variations ,such temperature for a period of time, suflicient to permit the cracking reaction to take place, while maintaining the same in substantially liquid phase, passing the heated oil before substantial cracking thereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein the temperature of the oil is permitted to drop below the temperature at which portions thereof would crack, and withdrawing the vapors from said chamber.

2. In the art of petroleum distillation, heating the oil to be distilled to the temperature at which portions thereof would crack if maintained at such temperature for a period of time sufficient to permit the cracking reaction to take place, while maintaining the same in substantially liquid phase, and immediately passing the heated oil before substantial cracking thereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein the temperature of the oil is dropped below the temperature at which portions would crack, withdrawing the evolved vapors, and discharging from said vaporizing chamber the unvaporized portions thereof.

3. In the art of petroleum distillation, rapidly passing the oil in a relatively small stream through a heating element, thereby raising the temperature thereof to the temperature at which portions of such oil would crash if maintained at such temperature for a period of time sufficient to permit the cracking reaction to take place, while maintaining such oil in substantially liquid phase by suitable pressure, immediately discharging the heated oil before substantial cracking thereof occurs into a vaporizing chamber main-' tained under a reduced pressure less than atmospheric, wherein portions of the oil vaporize and thereby cause the temperature of the oil to drop 7 below the temperature at which portions thereof would crack, withdrawing the resultant vapors, and suitably withdrawing the resultant unvaporized product.

4. The production of asphalt from petroleum oil, which consists in heating a water-free oil to a temperature exceeding 400 F. at which portlons of the oil would crack if maintained at such temperature for a sumcient time, immediately passing the heated oil in substantially liquid phase before substantial cracking occurs to a vaporizing chamber maintained under a pressure less than atmospheric, applying heat to such vaporizing chamber to raise the temperature thereof to the desired maximum distilling temperature, and withdrawing the evolved vapors to separate asphalt as the resultant unvaporized product of such operation.

5. In the art of petroleum distillation, heating oil to be distilled to the temperature at which portions thereof would crack if maintained at such temperature for a period of time sufficient to permit the cracking reaction to take place while maintaining the same in substantially a liquid phase, passing the heated oil before substantial cracking thereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric wherein the temperature of the oil is permitted to drop below thetemperature at which portions thereof would crack, withdrawing vapors from said chamber, extracting from the vapors the tarry "mist without substantial scrubbing of vapors in said step, and thereafter fractionally condensing the vapors into a number of distillates of different boiling points.

8. Inthe art of petroleum distillation, heating the oil to be distilled to a temperature at which portions thereof would crack if maintained at such temperature for a period of time sufllcient to permit the cracking reaction to take place, while maintaining the same substantially liquid phase, immediately passin the heated oil before substantial cracking thereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein the temperature of the oil is dropped below the temperature at which portions would crack, extracting from the vapors the tarry mist without substantial scrubbing of vapors in said step, and thereafter fractionally condensing the vapors into a number of distillates of different boiling points.

7. In the art of petroleum distillation, rapidly passing the oil in a relatively small stream through a heating element, thereby raising the tempera ture thereof to the temperature at which portions of said oil would crack if maintained at such temperature for a period of time sufficient to permit the cracking reaction to take place, while main= taining such oil in substantially liquid phase by suitable pressure, immediately discharging the heated oil before substantial cracking thereof occurs, into a vaporizing chamber maintained under a'reduced pressure less than atmospheric, wherein portions of the oil vaporize, thereby causing thetemperature of the oil to drop below' the temperature at which portions thereof would crack, withdrawing the resultant vapors,'suitably withdrawing the resultant unvaporized product, extracting from the vapors the tarry mist without substantial scrubbing of vapors in said step, and thereafter fractionally condensing the vapors into a number ,of distillates of different boiling points.

8. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporizing temperature when heated under a substantial vacuum and substantially preventing decomposition of. such heavy lubricating oil fractions, comprising feeding into a single distilling zone oil containing such heavy lubricating oil fractions and lighter lubricating oil fractions, maintaining the distilling zone at substantially a onstant temperature below the decomposing temperature of said heavy fractions and under a reduced pressure to vaporize said heavy fractions in the presence of the vapors of said lighter fractions, and continuously withdrawing said resulting mixed vapors and residue from the distilling zone in such relation of volume and speed as to cause the vaporization of both said heavy and light lubricating oil fractions.

9. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporization temperature when heated under a substantial vacuum and substantially preventing decomposition of such heavy lubricating oil fractions, comprising feeding into a single distilling zone an oil containing the residuum and substantially all the viscous constituents originally present in the crude 611, including cylinder oil stocks and lower boiling point lubricating' oil fractions, maintaining the distilling zone lighter lubricating oil fractions, continuously withdrawing the resulting mixed vapors and the residue from the distilling zone in such relation of volume and speed as to cause the vaporization of substantially all the lubricating oil fractions contained in said feed oil.

10. In the art of petroleum distillation, heating e oil to be distilled to a temperature at which' portions thereof would crack if maintained at such temperature for a period of time sufficient v to permit the cracking reaction to take place,

' paratively wide boiling range including both light and heavy lubricating oil fractions, the process which comprises continuously heating the oil to a temperature at which portions thereof would crack if maintained at such temperature for a period of time suilicient to permit the cracking reaction to take place, passing the heated oil before substantial cracking thereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein a portion of the oil including both lighter and heavier fractions is vaporized and wherein the temperature of the oil is permitted to drop below the temperature at which portions thereof would crack, withdrawing vapors and withdrawing the unvaporized portion of the oil from said chamber.

12. In the distillation of petroleum oils of comparatively wide boiling range including both light and heavy lubricating oil fractions, the process which comprises continuously=heating the oil to a temperature at which portions thereof would crack if maintained at such temperature for a period of time sufiicient to permit the cracking reaction to take place, passing the heated oil before substantial cracking thereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein a portion of the oil including both lighter and heavier fractions is vaporized and wherein the temperature of the oil is permitted to drop below the temperature at which portions thereof would crack, subjecting vapors evolved from said chamber to fractionation whereby separation of the lighter from the heavier fractions is effected, and withdrawing the unvaporized portion of the oil from the chamber.

13. In the art of petroleum distillation, heating the oil to be distilled to a temperature at which portions thereof would crack if maintained at such temperature for a period of time sufiicient to permit the cracking reaction to take place, passing-the heated oil before substantial crackingthereof takes place to a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein the temperature of the oil is'permitted to drop belowthe temperature at which portions thereof would crack, separately withdrawing the vaporized ,and unvaporized portion from said chamber, and thereafter fractionally condensing the vaporized portion into a number of distillates of different boiling range.

14. In the art of petroleum distillation, rapidly passing the oil in a relatively small stream through a heating element, thereby raising the temperaturethereof to the temperature atwhich portions of such oil would crack if maintained at such temperature for a period of time sufiicient to permit the cracking reaction to take place, immediately discharging the heated oil before substantial cracking thereof occurs into a vaporizing chamber maintained under a reduced pressure less than atmospheric, wherein portions of the oil vaporize and thereby cause the temperature of the oil to drop below the temperature at which portions thereof would crack and separately withdrawing the vaporized and unvaporized portions from said chamber.

15. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporizing temperature when heated under a substantial vacuum and substantially preventing decomposition of such heavy lubricating oil fractions, comprising feeding into a single disoil fractions and lighter lubricating oil fractions, maintaining the distilling zone at substantially a constant temperature below the decomposing temperature of said heavy fractions and under a reduced pressure to vaporize said heavy fractions in the presence of the vapors of said lighter fractions, continuously withdrawing said resulting mixed vapors and residue from the'distilling zone in such relation of volume and speed as to cause the vaporization of both said heavy and light lubricating oil fractions, and thereafter fractionally condensing the vaporized material into a number of distillates of different boiling range.

16. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporizing temperature when heated under a substantial vacuum .and substantially preventing decomposition of such heavy lubricating oil 'fractions, comprising heating an oil containing stant temperature below the decomposing temperature of said heavy fractions and under a reduced pressure less than atmospheric to vaporize said heavy fractions inthe presence of the vapors of said lighter fractions, and continuously withdrawing said resulting mixed vapors and residue from the distilling zone in such relation of volume and speed as to cause the vaporization of both said heavy and light lubricating oil fractions.

1'7. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporizing temperature when heated under a substantial vacuum and substantially preventing decomposition of such heavy lubricating oil fractions, comprising heating an oil containing such heavy lubricating oil fractions and lighter lubricating oil fractions under superatmospheric pressure to a temperature at which portions thereof would crack if maintained at such temperature for a period of time sufficient to permit the cracking reactions to take place, feeding the oil before substantial cracking thereof takes place into a single distilling zone, maintaining the distilling zone at substantially a constant temperature below the decomposing temperature of said heavy fractions and under a reduced pressure to' vaporize said heavy fractions in the presence of the vapors of said lighter fractions, continuously. withdrawing-said resulting mixed vapors and residue from the distilling zone in such relation of volume and speed as to cause the vaporization of both said heavy and light lubricating oil fractions, and thereafter fractionally condensing the vaporizing material into a number of distillates of different boiling range.

18. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom hari za decomposing temperature below their vaporizing temperature when heated under a substantial vacuum and substantially preventing decomposition of such heavy lubricating oil fractions, comprising rapidly passing an oil containing such heavy lubricating oil fractions and lighter lubricating oil fractions in a relatively small stream through a heating element wherein it is heated to the desired temperature, feeding the oil before substantial cracking thereof takes place into a single distilling zone, maintaining the distilling zone at substantially a constant temperature below the decomposing temperature of said heavy fractions and under a reduced pressure less than atmospheric to vaporize said-heavy fractions in the presence of the vapors of said lighter fractions, and continuously withdrawing said resulting mixed vapors and residue from the distilling zone in such relation of volume and speed as to cause the vaporization of both said heavy and light lubricating oil fractions.

19. A continuous process of distillingpetroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporizing temperature when heated under a substantial vacuum and substantially preventing decomposition of such heavy lubricating oil fractions, comprising rapidly passing an oil containing such heavy lubricating oil fractions and lighter lubricating oil fractions in a relatively small stream through a heating element under superatmospheric pressure wherein it is heated to the desired temperature, feeding the oil before substantial cracking thereof takes place into a single distilling zone, maintaining the distilling zone at substantially a constant temperature below the decomposing temperature of said heavy fractions and under a reduced pressure to vaporize said heavy fractions in the presence of the vapors of said lighter fractions, and continuously withdrawing said resulting mixed vapors and residue from the distilling zone in such relation of volume and speed as to cause the vaporization of both said heavy and light lubricating oil fractions.

20. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporization temperature when heated under a substantial vacuum and substantially preventing the decomposition of such heavy lubricating oil fractions, comprising heating an oil containing theresiduum and substantially all of the viscous constituents originally present in the crude oil, including cylinder oil stocks and lower boiling point lubricating oil fractions, to a temperature at which portions thereof would crack if maintained at such temperature for a period of time sufficient to permit the cracking reaction to take place, feeding the oil before substantial cracking thereof takesv place into a single distilling zone, maintaining the distilling zone at a constant temperature below the decomposing tenperature of the said heavy lubricating oil fractions comprising a cylinder oil stock and under a reduced pressure to vaporize said cylinder oil stock in the presence of the vapors of said lighter lubricating oil fractions, continuously withdrawing the resulting mixed vapors and the residue from the distilling zone in such relation of volume and speed as to cause the vaporizing of substantially all of the lubricating oil fractions contained in said feed oil, and thereafter fractionally condensing the vaporized material into a number of distillates of different boiling range.

21. Production of asphalt from petroleum oil which consists in heating the oil under superatmospheric pressure to a temperature within the range 700 to 900 F. at which portions of the oil would crack if maintained at such temperature for a sufficient time, and immediately passing the heated oil in substantially liquid phase before substantial cracking occurs to a vaporizing chamber maintained under a pressure less than atmospheric wherein a portion of the oil is vapor zed to separate asphalt as the resultant unvaporized product of such separation.

22. A continuous process of distilling petroleum oil to evolve therefrom viscous distillate oil fractions having a decomposing temperature below their vaporization temperature under a substantial vacuum and an asphaltic residuum, and substantially preventing the decomposition of such viscous distillate fractions and said asphaltic residuum, comprising feeding into a single distilling zone an oil containing residuum, said high boiling viscous oils and also less viscous oils of lower boiling range, maintaining the distilling zone at a constant temperature below the decomposing temperature of said residuum and high boiling viscous oils and under a reduced pressure to vaporize said high boiling viscous oils inthe presence of the vapors of said lighter and less viscous oil, continuously withdrawing the resultant mixed vapors and asphaltic residue from the distilling zone in such relation of volume and speed as to cause the vaporization of said heavy oil distillate fractions whereby an unvaporized product comprising asphalt is produced.

23. A continuous'process of distilling petroleum oil to evolve therefrom viscous distillate oil fractions having a decomposing temperature below their vaporization temperature under a substantial vacuum and an asphaltic residuum, and substantially preventing the decomposition of such heavy oil distillate fractions .and said asphaltic residuum, comprising heating an oil containing residuum, said higher boiling viscous oils and also less viscous oils of lower boiling range to a temperature at which portions thereof would crack if maintained at such temperature for a sufllcient time,'feeding the oilbefore substantial cracking occurs to a single distilling zone, maintaining the distilling zone at a constant tempera= ture below the decomposing temperature of said residuum and high-boiling viscous oils and under a reduced pressure to vaporize said high;

boiling viscous oils in the presence of the vapors of said lighter and less viscous oil, and continuously withdrawing the resultant mixed vapors and asphaltic residue from the distilling zone in such relation of volume and speed as to cause the vaporization of said heavy oil distillate fractions below their vaporization temperature when heated under a substantial vacuum and a residue; and substantially preventing the decomposition of such heavy lubricating oil fractions and said residue, comprising feeding into a single distilling zone an oil containing the residuum and substantially all the viscous constituents originally present in the crude oil, including cylinder oil stocks and lower boiling point lubricating oil fractions, maintaining the distilling zone at a constant temperature below the decomposing temperature of said residuum and high-boiling heavy lubricating oil fractions comprising the cylinder oil stock, and under a reduced pressure to vaporize said cylinder oil stock in the presence of the vapors of said lighter lubricating oil fractions, continuously withdrawing the resulting mixed vapors and the residue from the distilling zone in such relation of volume and speed as to cause the vaporization of said heavy oil distillate fractions whereby an unvaporized product comprising the residue is produced.

25. A continuous process of distilling petroleum oil to evolve heavy lubricating oil fractions therefrom having a decomposing temperature below their vaporization temperature when heated under a substantial vacuum and a. residue, and substantially preventing he decomposition of such heavy lubricating 0' fractions and said residue, comprising heating an oil containing the residue and substantially all the viscous constituents originally present in the crude oil including cylinder oil stocks and lower boiling-point lubricating oil fractions to a temperature at which portions thereof would crack if maintained at such temperature for a sufiicient time, feeding the oil before substantial cracking occurs to a single distilling zone, maintaining the distilling zone at a constant temperature below the decomposing temperature of said residuum and highboiling heavy lubricating oil fractions comprising/the cylinder oil stock, and under a reduced pressure to vaporize said cylinder oil stock in the presence of the vapors of said lighter lubricating oil fractions, continuously withdrawing the resulting mixed vapors and the residue from the distilling zone in such relation of volume and speed as to cause the vaporization of said heavy oil distillate fractions whereby an unvaporized product comprising the residue is produced.

' OTTO BEHIMER.

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