US2787582A - Production of lubricating oils - Google Patents

Description

April 2, 1957 c. H. wATKlNs Erm.. 2,787,582

PRODUCTION OF' LUBRIATING OILSv rFiled April 12, i955 United States Patent I O PRODUCTION OF LUBRICATING OILS Charles H. Watkins, Western Springs, and Armand J. de Rosset, Clarendon Hills, Ill., assiguors to 'Universal Oil Products Company, Des Plaines, Ill., a corporation of Delaware Appncanon'nprn 12, 195s,..seria1No. 500,732

`s claims. (ci. 196'49).

This invention relates to 'a process for the preparation of lubricating oil and in particular relates toa process for the conversion of higher boiling petroleum stocks to lubricating oils and, to improve virgin lubricating oil fractions. .y

Iri recent years -there has been. adiminishing demand f orheavier petroleuin'fractions which -boilin the fuel oil range and heavier and at the same time the use of heavy lubricating oils Ihas diminished. Refiners of lubricating oils have therefore found that therepis linsuiiicient virgin lubricating oil in the boiling range desired, that is the lighter lubricating oil boiling range, to satisfy the demands, while at the same time a problem has been created in profitably disposing of the heavier oils. The desirable lubricating oils are those boiling in the range of from about 600 F. to about 950 F. The best lubricating oilsl are composed of paratiinic and naphthenic hydrocarbons preferably containing an `abundance of isomeric molecules sothat the melting point is low yand the viscosity is low. Tjhese lubricating oils contain waxes which are long, straight chain hydrocarbons and these waxes are in solution or suspension inthe lubricating oil and must be removed therefrom lbefore the oil is suitable for lubricating. The oil fractions varcfdewaxed by many methods, probably the most successful of. which comprises'mixing the entire oil fraction with a suitable solvent such as -a mixture of toluene, benzene, and acetone, cooling until thewax precipitates and then iiltering the wax from the mixture, followed by separation of the solvent from the oil. The presence of wax in the original oil fraction, although an impurity, is not undesirable since Wax is an extremely valuable by-product whichin many cases is worth to the reiiner as' much as the oil from which it was -rhsneavier oii-sboiling above. 90o?? F., that isl ons heavier than thesdesirablezlight lubricating oil, will have roughly the same chemical characteristics as ithelubri` eatingl oilsince the two fractions are `obtained from the same stock, h owever,the molecules in lthe heavier oil will 'be larger homologs of those in the lighter stock. The heavier oil, following removal of the ldistillate lubrieating oil is called cylinder stock, which may be dewaxed and deresined afterwhich it is known as Bright stock which is useful for 'blending with dewaxed lighter oils to form heavier grades of lubricating oil. When not used for blending, cylinder stocks and Bright stocks may serve as a portion of the charge or starting'material for this process as hereinafter described in greater detail. These heavier ymaterials are hydrogen deficient relative to the desirable 'lubricating oil fraction and ltherefore, in order to be -converted into suitable lubricating oils, must be hydr-ogenatd. Other stocks which may be used .as a portion of the beginning material in this process are heavier fractions from other crude's and cycle oils which may boil higher than the lubricating oil or partly in the boiling range of lubricating oil but which are unsuitable as lubricating "oil,`

l a light lubricating oil fraction.

;Although a comparison of the characteristics of the starting material and the ultimately desired material from -this process would suggest a hydrocracking operation, it has been found that large yields of lubricating oil cannot be obtained by hydrocracking. When a hydrocracking operation is started, lube oil is obtained, however, the recycling of material boiling higher than 950 F. from the synthetic crude or total eluent from the hydrocrack-` ing process, causes the degree of unsaturation of the combined feed to the process to continuously increase. Unsaturation of the charge stock is a serious detriment to this process inasmuch as unsaturated material in this boiling range, that is above 900 F., forms excessive quantities of coke when heated Iand therefore requires more extensive regeneration with the resultant ineiciency of the process and loss of material. For example, when the process is effected in a fixed bed there are only brief.

reaction cycles between periods of regeneration.

Another objection to hydrocracking is that the heretofore mentioned valuableV wax material is destroyed since the long, straight chain molecules of wax are Vulnerable to cracking and therefore the synthetic crude contains little. tion arel experienced when conventional hydrocracking is used as for example the production of increased quan-v tities of gasoline at the expense of the yield of lubricating oil and wax.

Our invention provides a specific process for the production of a superior grade of lubricating oil from the charge stock which process may 'be operated to convert the charge stock to extinction without serious Coking difficulties and which process not only does Vnot destroy the valuable wax product but actually increases the amount and quality of wax produced.

The Bright stock prepared as hereinbefore described may find use as a blending stock to increase the weight of Therefore when the process of this invention is operated to produce for example, S. A. E. No.. 10 grade lubricating oil and a certain amount of No. 20 or No. 30 grade is also desired, these heavier grades can be produced by blending the proper amounts of Bright stock with the product from the process.= Therefore, it is frequently desirable, especially for lubricating oil to be consumed in the warmer climates and the Warmer months, to lhave Bright stock available for Iblending.

As hereinbefore described it is very undesirable to have unsaturation in the heavier stock from the synthetic crude from ythis process since it causes fouling of the catalyst,

heaters and other parts of the plant, however, it' is also undesirable to have unsaturation in the portion of the synthetic crude that is not recycled. The desired light lubricating oil produced in this process is not recycled to the reaction and therefore not again subjected to reaction conditions, however, this fraction should also be saturated and stable since this increases its desirability as'a lubricating oil. Although isomeric molecules are desirable in lubricants, unsaturated molecules are not and hence a light lubricating oil fraction from this process or from the virgin crude may be improved by hydrogenation which saturates both olefinic compounds to produce par.; ains vand-aromatic compounds to produce naphthenes,

both reactions substantially improving the lubricating qualitiesy of the stock upon which they were performed. The ysaturation reactions improve the heavier Bright stock lsimilarly to the improvement effected on the lighter stocks and therefore hydrogenation steps on heavier stocks lare desirable when they are used either as a blending stock in lubricating oil or as a recycle stock to the process.

,It is therefore an object of this invention to produce aj j saturated light lubricating oil fraction vfromv a substan-l Other disadvantages of yield and product distribu-y tially hydrocarbon material and to obtain high yields of product by recycling the unreacted material to the conversion zone.

In one embodiment this invention provides a method for producing lubricating oil which comprises -separating a petroleum material into at least a light lubricating oil fraction and a bottoms fraction, passing at least a portion of said bottoms fraction into contact with a catalyst comprising a compound containing a metal from the left hand column of group VI and an iron group component at a temperature of from about 750 F. to about 850 F. and a pressure in excess of about 100 p. s. i., separating the resultant converted material into a synthetic light lubricating oil fraction and a synthetic bottoms fraction, returning at least a portion of the latter into contact with said catalyst, commingling the resultant synthetic light lubricating oil fraction with the aforesaid light lubricating oil fraction and passing the resultant mixture into contact with a hydrogenating catalyst under hydrogenating conditions and dewaxing the resultant hydrogenated light lubricating oil to produce the 4aforesaid lubricating oil.

In a preferred embodiment of this invention the catalytic material comprising group VI and group VIII metal components is disposed on a carrier material having non-cracking characteristics and the destructive hydrogenation process is elected with regeneration of the catalytic material.

As hereinbefore stated the charge to this process is separated into at least a light lubricating oil fraction and a bottoms fraction. The charge may comprise a total crude oil and the fractionation may be elected in several fractionators wherein various fractions are removed or in a single fractionator wherein the lighter material is taken from the top of the column, and the lubricating oil fraction is taken as a side cut while the bottoms form the charge to the destructive hydrogenation zone. The charge to this process may comprise a distillate after gasoline, kerosene, and lighter material are removed or it may be a synthetic crude from a thermal cracking or catalytic cracking operation. The charge may also cornprjise a blend of synthetic crude and natural or virgin crude o il or it may consist of or be blends of any of these alone or in combination. The other sources of charge to this process may include the product from destructive hydrogenation of shale, coal, wood, etc. Aboutl the only limitations upon the charge stock of this invention 'are that Vit must beV substantially hydrocarbon in nature, that is having a predominant number of molecules hydrocarbonaceous although they may be commingled with sulfnrfcontaining molecules such as mercaptans, thiophencs etc. or nitrogen-containing molecules or oxygenfcontaining molecules which will gener-V ally be considered impurities in the total stock. It is preferred that the charge to the unit be parairlnic4 in na-. ture rather than asphaltic inasmuch as paranic charges contain substantially smaller quantities of aromatic and condensed ring polynuclear compounds which form -asphaltenes and precipitate out of solution to form black carbonaceous deposits upon heater tubes and catalytic particles. When asphaltic stocks are employed in the process of this invention it is preferred that they be deasphalted by any suitable method lprior to introduction into the unit. Suitable methods of deasphalting and deresining stocks will be discussed in greater detail hereinafter.

As hereinbefore stated, the charge stock to the process. of this invention must be fractionated into at least a light lubricating oil fraction and a bottoms fraction. The fractionation zone of this invention is contemplated as being ya conventional fractionator containing suitable means. for effecting separation of material by virtue of Vdilference in boiling point. The fractionationzone will contain some means of etecting intimate contact between a rising molybdenum-iron, and other variations.

vapor stream and a descend-ing liquid stream and may contain for example, such contact inducing devices as bubble trays, perforated decks, packing material, ctc. The object of the fractionation is to separate material already boiling in the light lubricating oil range from heavier material so that only the material requiring treatment need be treated.

The bottoms material from the fractionation zone is roughly analogous to the light lubricating oil desired, however, the Vmolecules in this material are generally heavier homologs than those in the lighter fractions. The bottoms will generally boil above 900 F Iand preferably above about 950 F. and `will usually comprise heavy paranic material and waxes. It the bottoms fraction from the fractionation zone is highly aromatic it will preferably be treated to precipitate these aromatics as asphalt or asphaltenes after which treatment it is known as cylinder stock and when further treated to be dewaxed and deresined it is called Bright stock, the characteristics o f which were hereinbefore described.

The heavy material is passed to the destructive hydrogenation zone where it is contacted with the heretofore mentioned catalyst at reaction conditions.

As hereinbefore stated, the catalyst to be used in the process of this invention comprises a metal component from the left hand column of group Vl and an iron group metal component. These components are preferably disposed upon a base having no cracking activity. The preferred metal components are cobalt and molybdenum, however, the other members of the indicated groups may be used with success in such combinations as chromium-cobalt, tungsten-cobalt, chromium-nickel, The metal com :piment may be in the form of the metal or in the form ol its oxide, sullide, halide or other compound and usually when the charge stock contains combined sulfur the metal components will be at least partially in the form or" their suldes during processing. The metals may be composited with the non-cracking base when such is used by any of the well known methods such as impregnation from solutions of the soluble salt of the metals either concurrently or successively followed by precipitation by treatment with precipitating reagent such as H25 or by evaporation of the solution and oxidation of the metallic component. The precipitation may or may not be followed by reduction, for example with hydrogen under high temperature. The final catalyst will be in the form of distinct particles which may be of any convenient size. For xed bed downflow operations, spheres, pellets, or pills of from about l@ inch to A inch major dimension are preferred and for upow or uidized operations smaller particles are preferred. Particles in the range of l0 to +16' mesh have been found to give particularly good results, indicating that the distribution of material through a bed of that size particle is particularly good.

The non-cracking base or the base having no cracking activity as described herein may also be characterized as a non-acidic base. It is desired that the base material used have no cracking activity as a catalyst although it may enhance the ability of hydrocarbons to crack by providing a het dstended contact surface. Perhaps the best description of the material is but an enumeration of a number of specific materials which may be used. Therefore, silica, alumina, magnesia, pnmice, kieselguhr, may be used and these may be steam deactivated or heat deactivated prior to use. The silica, alumina, magnesia, and zirconia may be naturally occurring or preferably syntheticallyprepared as by forming a hydrosol of the material and allowing it to gel either as a cake or in the form of spheres, or powders which may later bc pellcted into aggregates of whatever size is desired. Another suitable base may be a carbonaceous base such as coke, coal, charcoal, etc. which material causes adsorption of molecules of hydrocarbon into the proximity of the catalytic material without having cracking activity ol its own. Another suitable base may be a silica-alumina base, which` has good properties of surface area-andr strength, however, this silica-alumina base must be substantially totally deactivated with respect to cracking activity prior to use in this process by steam deactivation, heat deactivation, treatment with ammonia or in a preferred method byincorporating an alkali or alkaline earth material in the composite which destroys the acidic character of the silica-alumina and renders it inert with regard to cracking. It is understood that other bases which satisfy the qualifications set out herein may be employed within the broad scope of this invention.

Whether a base has catalytic cracking activity or not may best be determined by the character of the product resulting from it. In the present invention, using the catalysts specified in the manner specified there will not be catalytic cracking as evidenced by the low yields of gasoline and particularly by the occurence of dealkylation of high boiling kisoparallins to form waxes. A catalyst with cracking activity will cause cleavage of these long, straight chain wax molecules lsomewhere in the middle of the chain, resulting in the high yields of gasoline that are characteristic of catalytic cracking, at the expense ofthe waxes and Wax forming molecules in the feed.

The destructive hydrogenation will be effected at a temperature of from about 750 F. to about850 F. since it has been found that below 750 F. there is little conversion whereas above 850 F. thermal cracking reactions are effected which cause the undesirable destruction of waxes and unsaturation of the recycle stock. It is thought that the cleavage of carbon-carbon bonds in this process is due to the tendency to hydrogenate two adjacent carbon atoms in a molecule and that the hydrogenation activity is the prime source in causing cleavage rather than thermal cracking activity. This analysis is more or less substantiated by the fact that the catalytic material has no cracking activity and yet cleavage of carbon-carbon bonds occurs at a temperature below that at which thermal cracking should occur, however, it is not intended to limit this invention to the correctness of this analysis.

The process will be elected at a superatmospheric pressure in order to eiect the desired hydrogenation. Therefore, a hydrogen atmosphere will be required in the reaction zone and this hydrogen atmosphere should be at a pressure of about 100 p. s. i. or higher and may be any pressure up to 10,000 p. s. i. or more when desired. It is contemplated that the process of this invention will be effected at ordinary space velocity, that is from about 0.25 to about volumes of charge per volume of catalyst present 'per hour, however, it is to be borne in mind that the space velocity may be varied greatly and in some cases it may bev sufficiently high so that a higher temperature than the preferred temperature described above may be used. The excessive equipment requirements for such high space velocity are such that only under special circumstances would they ever be used and under those circumstances of course a higher operating temperature will accordingly be used.

The process will preferably include aregeneration cycle since a certain amount of coke formation will occur in the catalyst bed, however, the regeneration is not conv templated to be of thesame magnitude as in a conventional crackingoperation. For example, the process of this invention may function for several weeks or longer before regeneration of the catalyst is required after which a short regeneration period, for example 1 or 2 days or less, may be required, after which another operating period of several weeks may be used. Therefore, the preferred method of effecting the present process is as a fixed bed of catalyst through which the charge stock is passed in either an upward or downward direction with intermittent periods of regeneration and this method is preferred inasmuch as it represents the cheapest type of plant to build and therefore the most desirable when the nature of the process permits. It is not intended, how-f ever, to limit this invention to a fixed bed operation since a iixed iluidized bed, a uidized bed with cyclic transfer of catalyst from the reaction zone to the regeneration zone and back to the reaction zone or a moving bed process wherein a slowly descending catalyst bed discharges from the reaction zone into a regeneration zone and the regenerated catalytic material is transported to and deposited on the top of the catalyst bed in the reaction zone after suitable treatment with regeneration gases may be used.

The regeneration cycle must be controlled so that the heat of regeneration does not destroy the catalytic activity of the hydrogenation catalyst employed and the maximum allowable heat will depend upon the particular catalytic material used. The temperature of regeneration must also be sufficiently low so as to not fuse the base material and this again will depend upon the particular base material used. Ordinarily regeneration temperatures will not exceed 1400 F. and they may be maintained below the maximum temperature bylimiting the amount of oxygen in the regeneration gas or by blending cooling gases with' the regeneration gas prior to introduction into the're-v generation zone.

The light lubricating oil fraction from the virgin crude taken from the original fractionator in this process iS' blended with the light lubricating oil from the synthetic crude produced in the destructive hydrogenation zone which will hereinafter be referred to as synthetic light lubricating oil and the resultant blend is passed into a hydrogenation zone wherein unsaturated molecules contained in these fractions are hydrogenated. The hydro-v genation of the lubricating oil fraction improves the lubricating oil by making it more stable and at the same' time it substantially improves the quality of the valuable wax constituents contained therein by lowering the solidiiication point and improving its color thereby making it white 'and crisp instead of -brown and tacky. Whereas:

conventional processes for the manufacture of lubricating oil require solvent extraction steps to remove the aromatic compounds from the oils, the hydrogenationstep of this invention not only improves the oils as here-` inbefore described but also eliminates the need for a solvent extraction step in most cases by converting the. The hyaromatic molecules tonaphthenic molecules. drogenation step also produces a light colored oil containing fewv if any foreign color bodies and thereby climi-Q ess properly operatedc'osts less than the clay treating and it also improves the yield since the beneficial effect of af clay treating process is due to a removal of material while in the hydrogenation process the improvement is due to a change in its characteristics.

Therefore, the process of this invention includes passing the combined stream of virgin light lubricating oil" and synthetic light lubricating oil into a hydrogenation' zone wherein this stream is contacted with a hydrogenating catalyst at hydrogenating conditions. The hydrogenating catalyst may be any of those commonly used such as metals of group VIII, the left hand column of group VII, the left hand column of group VI, and the left hand column of group V and these may be used in the form of the pure metal or suitable compounds thereof-such as their oxides,"sulfides, halides, etc. The hydrogenating components may also be used in combination and particularly desirable combinations are those containing metal components from the left hand column of group VI and from the iron group such as cobalt-molybdenum, chrominut-nickel, tungsten-iron, etc. The catalytic material' 1s preferably disposed upon a base or carrier material v This latter savings has the double adwhich supports the catalyst in distended surface condition andv may promote the reaction by inducing a catalytic etect of its own. Some of the preferred carrier materials include silica, alumina, zirconia, magnesia, and are preferably synthetically prepared and may be used in combination such as` combinations of silica-alumina, silica-zirconia, boria-alumina, etc. The above materials may be synthetically prepared or naturally occurring when found as material such as kieselguhr, diatomaceous earth, montmorillonite clay, pumice, and magnesite, etc. Other suitable supports may be of the carbonaccous type and include larnpblack, coke, brown coal, activated charcoal, boneblacli, etc. Particularly preferred hydrogenation catalysts include nickel supported on natural or synT thetic silica, cobalt or molybdenum supported on alumina, platinum supported on alumina and chromium supported on alumina. When employing an alumina support it is frequently desirable to stabilize it with a small quantity of silica.

The hydrogenation zone will effect the desired hydrogenation reactions at a temperature of from about 100 F. toabout 500 F. and at a pressure of from about 100 p, s. i. to about 15,000 p. s. i. or more. There should be suicient contact time to permit the reactions to occur and the contact time will be regulated by the characteristics of the charge stock and the other operating conditions. Preferably, a liquid hourly space velocity of from about 0.25 to about 25 volumes of oil per volume of catalyst per hour will be employed and the contacting of the oil by catalyst will be effected in the presence of hydrogen. The reactions are preferably effected in the presence of a fixed bed of catalyst particles, however, a fixed fluidized bed, tluidized bed, moving bed or slurry may be employed as hereinbefore `described when such a process would be advantageous.

The hydrogenated light lubricating oil fraction as it cornes from the hydrogenation zone must be further treated in order to prepare it into a suitable material for lubricating. The light lubricating oil fraction contains wax and possibly resin and this material must be removed to give oil the proper qualities of viscosity and pour point. Many means are available for removing wax from oils and any of these are considered as within the broad scope of this invention. Wax may be removed by displacing it from solution by treatment with proplane which material. dissolves in the oil fraction to displace the -wax and may be later readily separated from the. oil since it has such a `substantially different boiling point than the fraction in which it is dissolved. Propane displacement may also be used as the means of deasphalting and deresining the oil. In conventional processes a lubricating oil must be deasphalted, dewaxed, deresined, solvent extracted and clay treated in order to take out the various heavy or undesirable fractions, and to remove aromatic hydrocarbons which destroy the lubricating qualities and to improve the color of the fraction. The present process produces an oil with no asphalt, very little resin and readily removable wax which is high quality. The process of this invention avoids the necessity of' solvent extraction and a clay treatment as hereinbeforeA described in detail.

The preferred method of treating the lubricating oil fraction` coming from thehydrogenation zone is to blend it with a, solvent or a mixture of solvents which dissolve the wax. material and which, upon cooling, precipitate it as a separate solid phase. Suitable solvents include toluene, benzene, acetone, methylethyl ketone, furfuryl,

As inrthe particular ex-v.

8 200 F. while the initial boiling point of the lubricating oil fraction is in the range of 600 F. The wax may also be removed by displacement from solution by propane in which case the boiling point difference between the oil and the purifying agent is even greater.

This invention may be more readily explained with reference to the accompanying drawing which shows one embodiment of this invention and is intended to be illustrative of rather than limiting upon its broad scope.

Referring to the drawing the charge stock to the process, which in this case will be considered a crude oil, enters through line 1 into the intermediate portion of fractionator 2 wherein it` is separated by conventional means into a light hydrocarbon phase passing from the top of fractionator 2 through line 3, which light hydrocarbon phase contains all of the normally gaseous hydrocarbons as well as gasoline, kerosene, naphtha and gas oil; a light lubricating oil fraction which passes through line 4 and which contains material boiling roughly from about 600 F. to about 950 F. and a bottoms fraction passing through line 5 which contains material boiling roughly in excess of 950 F. It is of course realized that these boiling ranges may be altered by operating the fractionation column differently and any desired fraction can be obtained as the seasonal demands or particular specifications dictate. The light hydrocarbons passing through line 3 are passed to other processes while the bottoms product passing through line 5 is passed largely into line 6, commingled with hydrogen-containing gas from line 7 and the resultant mixture of bottoms and hydrogen gas passes into conversion zone 9 via line 3. ln conversion Zone 9 the hereinbefore described reactions occur as a result of the contact of the mixture of hydrogen and bottoms with a catalytic material comprising a metal component from the left hand column of group V and an iron group component preferably disposed upon a base having no cracking activity. The resultant material passes through line 10 into gas separator li and the normally gaseous phase consisting largely of hydrogen, is separated from the normally liquid phase, which is known as the synthetic crude. The normally gaseous phase passes through line 12 and is commingled with the incoming hydrogen in line 7 or a portion of it may be vented through means not shown. The normally liquid portion, or the synthetic crude, passes through line 13 into an intermediate portion of fractionator ld.

Fractionator le serves roughly the same purpose as fractionator 2 in that it separates the synthetic crude entering through line 13 into a light hydrocarbon fraction passing through line 15 from the top of fractionator 14, a synthetic light lubricating oil fraction passing through. line i6 from an intermediate portion of the fractionator and a synthetic bottoms fraction passing through line 17 from the lower portion of the fractionator. The light hydrocarbon from line 15 may be commingled with that from the beforementioned line 3 and passed to whatever processing zone is used. The synthetic bottoms fraction passing through line 17 is preferably commingled with the virgin bottoms fraction passing through line 5 and returned via lines 6 and S to conversion Zone 9. The synthetic bottoms fraction may, however7 by operation of valves 18 and 19 to regulate the flow through lines 20 and 21, be passed into a dewaxing and deresining zone which will be described in more detail hereinafter.

The synthetic light lubricating oil passing through line 16 is commingled with the virgin light lubricating oil in line and the resultant blend passes through line lo into line 22 wherein it is commingled with hydrogen from line` 23. The mixture of hydrogen and light lubricating oil passes into a hydrogenation zone 24 wherein the hercinbefore described hydrogenation reactions are elfected in the presence. of a hydrogenating catalyst such as for example, platinum metal distended on alumina- The resultant material passing from hydrogenation zone 24 through line 25 is a saturated, stable, substantially sulfur and nitrogen-free material boiling in the range of light lubricating oil. This material passes through line 2S to gas separator 26 wherein itis separa-ted into a normally gaseous hydrogen rich phase which passes through line 27 and commingles with the beforementioned hydrogen in line 23 and a liquid lubricating oil fraction which passes through line 28 into dewaxing zone 29.

ln this embodiment the dewaxing zone functions by commingling the entire fraction with a solvent passing into the dewaxing zone by way of line 30 which dissolves wax from the fraction, which wax is subsequently precipitated as a solid and i'lltered from the liquid material. The wax passes from the dewaxing zone through line 31 while the dewaxed light lubricating oil and solvent pass through line 32 into a solvent separator 33. In solvent separator 33 the relatively simple fractionation is effected to separate the solvent material from the lubricating oil and the resultant separated solvent passes through line 34 and commingles with the incoming solvent in line 30. From the bottom of solvent separator 33 the desired light lubricating oil passes through line 35 as product.

By suitably regulating the temperature and conditions of the various fractionation and reaction zones the light lubricating oil in line 35 may be of any grade desired such as S. A. E. for example. The light lubricating oil may be raised to different or higher grade lubrieating oils by blending it with heavier lubricating oils which may be obtained as hereinafter described. This blending stock may be passed into contact with the product as it is formed by way of line 36 to form an ultimate product of whatever grade is desired.

The hereinbefore described synthetic bottoms fraction may, through suitable setting of valves 1S and 19, be passed with the virgin bottoms fraction from line 5 or into dewaxing and deresining zone 37 wherein it is treated with solvent entering by way of line 38 in a manner similar to dewaxing zone 29. The resultant wax material is withdrawn from line 39 while the dewaxed andderesined bottoms fraction which is mixed with solvent is passed through line 40 into solvent separator 41 wherein the solvent is separated and passed overhead through line 42 and returned to solvent line 38 while the dewaxed and deresined heavy lubricating oil passes through line 43. The material in line 43 may be withdrawn by opening valve 44 and withdrawing the heavy lubricating oil product or it may be passed, by opening valve 45 into the beforementioned line 36 to blend it with the light lubricating oil product as hereinbefore described. Although not shown, suitable valves and lines may be employed so that the virgin bottoms matenial from line 5 may be passed directly to dewaxing and deresining zone 37, or alternatively, a blend of both the virgin and synthetic material may be charged to zone 37. As hereinbefore stated, it must be realized that the gure herein described is intended to illustrate merely one preferred embodiment of this invention and is intended to include the ordinary and customary modications which may be made within the broad scope of this invention.

From the foregoing it may readily be seen that the process of this invention provides a means of producing high yields of lubricating oil from a fraction containing little or no lubricating oil and the lubricating oil 10 resulting from this process is superior to the virgin maten rial obtained by distillation. The process similarly increases the yield and quality of the extremely valuable wax by-product obtained from the processing of oils to produce light lubricating oils.

We claim as our invention:

l. The method for producing lubricating oil which comprises separating a petroleum material into at least a light lubricating oil fraction having an end boiling point above about 600 F. and a bottoms fraction having an end boiling point above about 900 F., passing at least a portion of said bottoms fraction into contact with a catalyst comprising a component containing metal from the left hand column of group VI and an iron group metal component at a .temperature of from about 750 F. to about 850 F. and a hydrogen pressure in excess of about p. s. i., separating the resultant converted material into a synthetic light lubricating oil fraction and a synthetic bottoms fraction, commingling the resultant synthetic light lubricating oil fraction with the first-mentioned light lubricating oil fraction and passing the resultant mixture with hydrogen into contact with a hydrogenating catalyst at a temperature of from about 100 to about 500 F., and dewaxing the resultant hydrogenated light lubricating oil fraction to produce the aforesaid lubricating oil.

2. The process of claim l further characterized in that said catalyst comprising a component containing a metal from the left hand column of group VI and an iron group metal component is disposed on a carrier having no cracking activity.

3. The process of claim l further characterized in that the catalyst comprising a component containing a metal from the left hand column of group VI and an iron group metal component. is subjected to periodic regeneration.

4. The process of claim l further characterized in that the synthetic bottoms fraction is at least partially dewaxed and blended with the light lubricating oil product.

5. A process for producing lubricating oil from a Wide boiling range hydrocarbon material which comprises fractionating said hydrocarbon material and separating therefrom a light lubricating oil fraction boiling between about 600 and about 950 F. and a bottoms fraction having an end boiling point above about 950 F., con- Y tacting at least a portion of said bottoms fraction, at a temperature of from about 750 to about 850 F. and a hydrogen pressure in excess of about 100 p. s. i., with a catalyst comprising a metal from the left-hand column of group VI of the periodic table and an iron group metal, separating a synthetic light lubricating oil fraction from the resultant products and commingling the same with the first-mentioned light lubricating oil fraction, subjecting the resultant mixture to catalytic hydrogenation at a temperature of from about 100 to about 500 F., and dewaxing the hydrogenated light lubricating oil thus formed.

References Cited in the le of this patent UNITED STATES PATENTS 2,360,622 Roetheli Oct. 17, 1944 2,554,282 Voorhies May 22, 1951 2,660,552 Blanding Nov. 24, 1955 2,700,015 Joyce Jan. 18, 1955

Claims (1)

1. THE METHOD FOR PRODUCING LUBRICATING OIL WHICH COMPRISES SEPARATING A PETROLEUM MATERIAL INTO AT LEAST A LIGHT LUBRICATING OIL FRACTION HAVING AN END BOILING POINT ABOVE ABOUT 600*F. AND A BOTTOMS FRACTION HAVING AN END BOILING POINT ABOVE ABOUT 900*F., PASSING AT LEAST A PORTION OF SAID BOTTOMS FRACTION INTO CONTACT WITH A CATALYST COMPRISING A COMPONENT CONTAINING METAL FROM THE LEFT HAND COLUMN OF GROUP VI AND AN IRON GROUP METAL COMPONENT AT A TEMPERATURE OF FROM ABOUT 750*F. TO ABOUT 850*F. AND A HYDROGEN PRESSURE IN EXCESS OF ABOUT 100 P.S.I., SEPARATING THE RESULTANT CONVERTED MATERIAL INTO A SYNTHETIC LIGHT LUBRICATING OIL FRACTION AND A SYNTHETIC BOTTOMS FRACTION, COMMINGLING THE RESULTANT SYNTHETIC LIGHT LUBRICATING OIL FRACTION WITH THE FIRST-MENTIONED LIGHT LUBRICATING OIL FRACTION AND PASSING THE RESULTANT MIXTURE WITH HYDROGENINTO CONTACT WITH A HYDROGENATING CATALYST AT A TEMPERATURE OF FROM ABOUT 100* TO ABOUT 500*F., AND DEWAXING THE RESULTANT HYDROGENATED LIGHT LUBRICATING OIL FRACTION TO PRODUCE THE AFOREAND LUBRICATING OIL.

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