US3005768A - Dehazing process - Google Patents

Description

Oct. 24, 1961 R. F. BURKE 3,005,768

DEHAZING PROCESS Filed Dec. 19, 1958 28 29 25 26 SIEVATE MOLECULAR -27 SIEVE UNIT DESORBATE 1 BLENDING TANK D C v SOLVENT DEWAXED OIL &

l0 SOLVENT DEWAXING 14 EPARATION SYSTEM E 2 ZONE 2 &

Robert F. Burke Inventor By 'RJwk-l Via/J1me Agent 3,005,768 DEHAZING PROCESS Robert F. Burke, Summit, N.J., assignor to Esso Research and Engineering Company, a corporation of Delaware Filed Dec. 19, 1958, Ser. No. 781,775 8 Claims. (Cl. 208-48) The present invention is concerned with the production of lube oil products of improved haze temperature characteristics. More particularly, it deals with a combination process whereby hydrocarbons may be dehazed in a highly economic and efiicient manner.

It is well known in the art to form various lubricating oils, commonly referred to as lubes, from hydrocarbon fractions derived from petroleum crude. The lube oil produced must pass various product quality tests, among them the cloud or haze point. The ASTM cloud point is defined as being the temperature at which Wax first starts to precipitate out in the lube oil, thus causing haze formation. It is determined by a standard ASTM procedure. Particularly in cases of low cold test lubes (those derived from naphthenic crude source), it has been found that wax, when given time, will often precipitate at temperatures considerably above the ASTM cloud point. Thus, the more accurate measure of tendency to haze is the haze temperature, which is herein employed to designate the true or equilibrium cloud point as opposed to the ASTM cloud point. The haze temperature is therefore the temperature at which a sample can be stored indefinitely without becoming haze.

The problem of haze formation is particularly acute in the case of lubricating and diesel oils which are to perform under low temperature conditions. As is readily appreciated, haze formation due to wax precipitation is aggravated by low temperatures. As well as having poor consumer visual appeal, wax precipitation during use may block free flow of lubricants, or interrupt the supply of diesel fuel.

Various means for alleviating this problem of haze formation have been advanced. It has been suggested to subject the entire oil product to solvent dewaxing in order to remove haze-forming constituents from the oil. However, the expense of such solvent dewaxing can not be justified in view of the low cost of the ultimate lube oil product. Unfortunately, in conventional solvent dewaxing the cost of the major items of equipment (chilling compressors and filters) is considerably more dependent on the oil fed then the relative small quantity of Wax to be removed. Moreover, the small concentration of wax to be segregated presents a formidable problem in that slight inefiiciencies of separations show up in unacceptable dewaxed products.

Thus there exists a need in the art for an economical process for removing the relatively small amount of hazeforming materials (generally of the order of 0.1 to 1.0 wt. percent) found in lubes and diesel oil products. More specifically, there is a particular demand for an efiicient process whereby the haze point of low cold test lubes (lubricants to be used under low temperature conditions') can be reduced to 35 F. or less, this being the range of good consumer reception and entirely satisfactory lube oil performance.

It has now been found that a unique combination of 3,005,768 I Patented Oct. 24, 1961 'ice selective molecular sieve adsorption and partial solvent dewaxing successfully lowers haze points to desirable levels in an economically attractive manner. More particularly, though it was generally known thatthe constituents giving rise to haze are normal paraffins and non-normals, such as isoparaflins and aromatics or naphthenes with long paraflinic side chains, it has now been found that the non-normals boiling below 1000* F. are not objectionable in that they will only cause haze at 20-30 'F., while non-normals boiling above about 1000 F. do raise haze point above acceptable limits.

In accordance with the present invention, the dehazing properties of a hydrocarbon oil are improved by:

(a) segregating the oil into a fraction boiling above 1000 F. (which has a high concentration of undesirable non-normals, haze precursors) and a fraction boiling below 1000 F. (which is relatively more rich in normal paraflins).

(b) subjecting the high boiling fraction (normally less than 20 volume percent of the original feed) to solvent dewaxing to remove non-normal parafiins, thus yielding an oil depleted in these constituents.

(c) Passing at least a portion of the low-boiling fraction through a molecular sieve adsorption zone adapted to adsorb normal paraffins from the fraction, and

(d) Combining the solvent-dewaxed oil and unadsorbed effluent of the above treatments thereby producing a lube oil of markedly decreased haze temperature.

operation is applied only to a minor portion of the feed,

and in particular to that portion containing materials (non-normal paraffins) which are both not readily capable .of molecular sieve separation and are a source of haze formation at temperatures above 35 F. Thus,

each step, in combination with the other, is a particularly effective and economical treatment in the overall scheme of lube oil dehazing.

It is to be clearly noted that applicants invention is not solvent .dewaxing, nor molecular sieve adsorption per se. Rather it is a specific and highly unique combination of these steps along with feed oil segregation, the

overall combination offering a solution to the problem of economical dehazing of relatively low cost petroleum hydrocarbons.

By way of clarifying nomenclature, the terms nonnormals or non-normal paraflins denote isoparaflins as'well as aromatics and naphthenes having long paraflinic side chains.

The various aspects and modifications of the present invention will be made more clearly apparent by reference to the following description, drawing and accompanying examples.

With reference to the drawing, shown therein is a system basically comprising separation zone 10, molecular sieve adsorption unit 11 solvent dewaxing system 12 along with blending tank 13,

,It is desired to dehaze ;a low cold test lube which has been derived from a naphthenic .icrudesource in a conventional manner, e. g. phenol extraction, acid treating or the like. The lube oil has a haze point of F.,

boils in the range of about 700 to 1100 F. and has a pour temperature of 20 'F. or lower and a low wax content of less than 0.5 wt. percent. In order to meet product specifications, its haze point must be reduced to 35 F- or less.

In accordance with the present invention, the hydrocarbon oil is fed by line 14 to zone 10. Separation zone is normally a distillation or fractionation unit, heated by conventional means not shown. In zone 10, the lube is subjected to rectification into a high boiling and one or more low boiling fractions. Conditions are maintained so as to cut the lube into a fraction boiling above 1000 F. (at atmospheric pressure), the remainder of the oil boiling below 1000 F. (at atmospheric pressure). This high boiling fraction comprises only about eighteen volume percent of the original feed oil and will contain substantially all the high boiling, branched parafiins initially present in the feed stock which will cause haze above 35 F. Conventional fractionation techniques, such as product stream recycle and the like, may be employed to obtain this cut point. In the present embodiment, separation zone 10 operates at a pressure of 10 mm. of mercury. Fractionation is efiected under vacuum conditions to prevent cracking of the oil feed. Temperature in zone 10 is about 200 to 500 F., e.g. 350 F.

The high boiling fraction is withdrawn by line 19 and passed to system 12. As noted previously, since this high boiling material is only a small fraction of the initial feed, system 12 and its accompanying facilities are substantially smaller (and thus less costly) than in solvent dewaxing processes heretofore advanced for dehazing of lube oils.

Solvent dewaxing is accomplished by fairly conventional methods. For simplicity sake, the drawing denotes a single vessel for eifecting solvent dewaxing, although actually a multiplicity of units, as is well known in the art, is employed, e.g. mixers, batch chillers, filter feed tanks, filters, etc. The term dewaxing zone" denotes the overall system. Numerous literature articles exist relating to solvent dewaxing technology, for example, see Petroleum Refinery Engineering by Nelson (3rd ed. 1949), or Petroleum Refining with Chemicals by Kalichevsky and Kobe (Elsevier 00., Amsterdam, 1956), and thus the solvent dewaxing step will not be discussed in excessive detail.

Any of the conventional dewaxing solvents, e.g. propane, ketones (methyl ethyl ketone, diethyl ketone, methyl propyl ketone) or mixtures thereof may be employed.

In'the present embodiment, dewaxing of the 1000 F.+ fraction is carried out at 10 F. employing a solvent mixture of 70 wt. percent methyl ethyl ketone and 30 wt. percent toluene introduced by line 31. A weight ratio of 3 parts solvent mixture to 1 part oil (to be dewaxed) is employed. Though only symbolically depicted in the drawing, the dewaxing operation comprises mixing the waxy oil feed with the solvent, thereafter charging the mixture to surface exchangers and then to chillers. In the chillers, the oil mixture is chilled continuously or batchwise to the desired filtering teperature, e.g. -10 F. Surge capacity is provided by the filter feed tank from which the chilled slurry flows by gravity to rotary vacuum filters, as permitted by a level controller in each filter.

As the filter drum rotates, wax cake builds up on the filter cloth while oil and solvent pass through. Cold solvent may be used to wash the wax cake as the unit revolves. A periodic blow back with an inert gas loosens the wax cake from the filter cloth just before it reaches a knife blade which diverts it to a trough. In the drawing, wax is removed from the dewaxing zone (to a collecting zone) by line 32.

The filtrate (oil plus solvent) is then passed through solvent recovery steps which normally will consist of a flash tower (for flashing off solvent) and a dewaxed oil stripper for purifying the oil product. The tower may operate at about 300 F. Dewaxed oil is withdrawn from the dewaxing system by line 33. The dewaxed oil now has a haze point of 0-10 F.

In some instances, it may be desirable to add 5 to 10 wt. percent wax to the l000 F.+ fraction to be dewaxed. Since the feed stream can be as low as 1% Waxy constituents, the larger quantity of wax makes filtering easier. For example, before dewaxing the l000 F.+ fraction, 8 wt. percent Wax is added. This wax together with the wax originally in the feed oil is filtered out and 8 wt. percent wax used again in treating fresh dewaxingfeed.

Returning to the separation zone, withdrawn therefrom is one or more fractions boiling below 1000 F. While it will normally be desired to subject all the lube oil boiling below 1000 F. to molecular sieve treatment, in some cases a light overhead fraction, i.e. boiling below 800 to 850 F., may be withdrawn by line 18 and used as a product lube oil constituent without dehazing treatment. This very light fraction either contains substantially no paraffin haze precursors, or such a small quantity of same as to give a haze point well within the 35 F. standard. The fraction removed by line 18 may comprise from 0 to 30 volume percent of the charge oil, and is ultimately mixed with the products of zones 11 and 12 to yield the desired low cold test lube. Alternatively, though normally not desired, a very small portion of the low boiling fraction (boiling below 1000 F.) withdrawn by line 15 may bypass sieve treatment by outlet 16, its poor haze properties being compensated for by the good haze properties of the eifiuents of the adsorption and extraction units.

In the present embodiment, all the fraction boiling below 1000 F. is withdrawn from zone 10 and passed to adsorption zone 11 by line 17. While not shown, it may be sent to a reservoir zone which in turn feeds unit 11. Adsorption zone 11 contains a mass of molecular sieve adsorbent.

Though now well known in the art, briefly described, molecular sieves are certain natural and synthetic zeolites characterized by a porous crystalline structure, the pores of which enable only molecules of a certain size to pass into them. The sieves have the ability to adsorb only molecules of a certain size and type while rejecting others. The pore diameter is substantially constant for a given sieve, and in general varies from about 4 to 15 A. Molecular sieves are typically an alkaline earth or alkali metal alumino-silicate, such as analcite, chabazite, etc. A more detailed description of molecular sieves may be had by reference to Journal of the American Chemical Society, vol. 78, page 5963 (December 1956).

The molecular sieves in unit 11 are of the 5 A. type, this pore diameter being suitable for the adsorption of normal paraflins from a hydrocarbon oil stream as well as excluding all molecules with larger cross sections. Unit 11 is preferably operated in the liquid phase under a pressure above 200 p.s.i.g., e.g. as high as 1000 p.s.i.g., and at a temperature of about 600-700" F., depending on the properties of the haze wax being adsorbed. Liquid phase adsorption at 400 p.s.i. g. and a temperature of about 650 F. is generally preferred. The optimum temperature for liquid phase dewaxing with 5 A. molecular sieve is a function of the average melting point of the adsorbable wax. At lower than optimum temperature the sieve tends to lose capacity too rapidly while at higher temperatures the oil under treatment tends to crack. The desired conditions will of course vary somewhat with the particular oil fraction to be treated.

The sieves in unit 11 may be in the form of a packed bed, slurry or the like, a packed, fixed bed being preferred. The low boiling fraction withdrawn from zone aces-res is normally cooled and cond n ed by con enser 21, thereatter bei g introduced by line 22 into the molecular sieve a sorpt on zon The oil passi g th u inlet 22 has a haze temperature of about, 70 F. As it contacts the molecular sieves, normalpataifins such as tricosane ar adsorbed by the ieves thu freeing the oil of hazen ucing, nonnal Si vate, i.e. unadsorbed oil, is withdrawn through line 25. Due to the removal of n ma pa afl n the unadsorbed oil has a haze point of 30 :F. or l ss. 1

s i W ll known in the art .of molecular i v a pion. a ter an extend d p riod the adsorption capacity or h sieves will b reached- Thi i i dic ed by an inreased c nc n ration f n rmal Parafiin in th iev product. At this point, valves and 26 are closed and unit 11 subjected to regeneration, i.e. removal of adsorbed normal paraffins from the sieve. This may be done by any number of conventional means such as raising the temperature of the unit and/or applying a vacuum, passing a hot gas stream such as methane, nitrogen, or oleiinic hydrocarbons through the unit, or burning the carbonaceous material oil with a diluted air stream. In the process illustrated, valves 24 and 29 are opened, and superheated steam is introduced through line 28. Desorbed normal parafiins (desorbate) is withdrawn through outlet 23, the paraffins being thereafter recovered from the stream and used as feed for various refinery processes, eg feed to catalytic cracking. When the sieves are fully regenerated, valves 24 and 29 are closed and the feeding of oil through line 22, and sievate removal through line 25, resumed, -If desired, the sieves may be cooled prior to commencing adsorption. Since the oil feed to the unit will contain less than 0.5 wt. percent normal parafiins for adsorption, unit 11 need not be regenerated too often. If desired, a series of molecular sieve units may be integrated so that oil is continuously undergoing adsorption treatment.

The sievate stream and the dewaxed oil of unit 12 are then passed to blending tank 13 by lines 27 and 33, respectively. Tank 13 is a conventional mixing tank or the like generally provided with agitation or mixing means- The blend withdrawn through line 30 is a good quality lube oil having a haze point less than 30 F and a boiling range of about 700 to 1100" F. (the same as the feed).

Various modifications may be made to the system described. Unit 10 may be any separation zone capable of separating the initial oil feed into a 1000 F. fraction and a fraction boiling below 1000" F. It is to be understood that although a cut point of 1000 F. is to be considered a necessary element of the present process, inherent inefficiencies may result in small deviations, e.g. 1 F., from this value. Though not normally desired due to economics, molecular sieve adsorption may take place in he vapo phase at substantially lower pressures (or even under vacuum) and higher temperatures than that indicated above.

Tabulated below is a compilation of data applicable to the system described.

Table 1 Separation zone: Preferred range Temperature, F 200 to 2600 Pressure, p.s.i.a 0.5 to 2 Vol. percent oil boiling 1000 F.+ 0 to 25 Molecular sieve unit:

Temperature, F V 600 to 700 Pressure, p.s.i.g 0 to 500 Sol en dewaxing unit:

Temperature, -10.- to -30 The benefits derived from the present invention are illustrated by the following experiments. In the experiments, various lube oils of unsatisfactory haze temperatures were treated. Table 2 sets forth the properties of the oils employed in the following example. All the oils are extracted lubes.

. Table 2.--Feed stock analysis Brand-- 40X 900K 500K Crude Source Tialgana Coastal Coastal Inspections:

Gravity at 60 F 24. 4 25.1 26. 4 Flash, F 500 490 470 Viscosity 100 F., SSU 1,103 1, 030 536 Viscosity 210 F., SSU 81.4 78. 5 j 59.3 Viscosity Index 67 66 64 Boiling Range 760 mm Hg,

,F 785-1, 020 700-1, 060 680-945 Refractive Index 5 C 1. 19 1. 4752 1. 4716 Conradson Carbon, Wt. per- 62 62 38 5 l5 15 as 75 .45

EXAMPLE 1 Lube oil denoted 900X and having the properties shown in Table 2, i.e. a haze point of 75F. and boiling range of about 700 to 1100 F., was subjected to molecular sieve adsorption with a 5 A. molecular sieve bed (2 inches in diameter and 90 inches long). The oil was fed at a rate of 0.5 w./w;/hr., the adsorption zone openating at 400 p.s.i.g. and 650 F. The sievate product (unadsorbed oil) had a haze temperature of 50 F. (substantially above the acceptable level of 35 F.).

In a contrasting run, the same 900K lube oil was first subjected to fractionation at about 660 F. and 10 mm. of mercury. That fraction of the oil boiling below 1000 F. at atmospheric pressure volume percent) had a haze temperature of 70 F. It was then subjected to treatment with the same type of 5 A. sieves as noted above; the adsorption zone operating at 400 p.s.i.g. and 650 F. An oil feed rate of /3 w./w./hr. was employed. The sievate product produced in this run had a haze temperature of 30 F.

This experiment shows that molecular sieve treatment of less than 1000 F. lube oil constituents results in commercially acceptable haze temperatures while sieve treatment of oil containing constituents boiling above 1000 F. fails to give a product of acceptable haze point.

EXAMPLE 2 Lube oil denoted 500X and having the'properties indicated in Table 2 was fractionated to recover constituent boiling in the range of 680 to about 1000 F. (atm. 760 mm. Hg). The less than 1000 F. fraction had a haze temperature of 45 F.

This fraction was then subject to adsorption with 5 A. molecular sieves at a temperature of 600 F., pressure 400 p.s.i.g, and an oil feed rate of /3 w./W./hr. The sievate product obtained had a haze temperature of 20 F.

This example further indicates that 5 A. molecular sieve treatment of lube oil constituents boiling below 1000 F. produces an oil having a haze point of commercially acceptable levels.

EXAMPLE 3 fube oil denoted 40X, and having the properties indicated in Table 2 (haze temperature of about 65-70 F. and boiling range of about 700-1100 F.), was directly subjected to molecular sieve adsorption with the same type 5 A. molecular sieve as employed in the previous examples. Adsorption was carried out at 650 F., 0 p.s.i.g. and an oil rate of /2 w./W./hr. The sievate prodnot of theadsorption step had a haze temperature of 50 F. (unacceptable).

However, when the same type of lubeoil was fractionated to recover material boiling from about 700 to 1000 F. and this fraction was treated with 5" A. molecular sieves (at 650 F 400 p.s.i.g, and /3 w'./w./hr. oil rate), a sievate product having a haze temperature of 35 F. was recovered.

This example further indicates that molecular sieve 7 treatment of lube oil constituents boiling below 1000 F. successfully reduces haze point to desired level whereas treatment of oils having a boiling rangebeyond 1000 F. does not give the necessary degree of dehazing. The example (along with Example 1) shows that molecular sieves are substantially ineffective in treating 1000 F.| material.

EXAMPLE 4 In order to test the importance of employing approximately a 1000 F. cut point in the initial separation stage of the present invention, the following experiment was run.

Lube -oi'l,'denoted 900X, was distilled to include the 10% to 90% overhead fraction (850 to 1060 F. boiling range). This fraction was sieve treated in the vapor phase (1w./w./hr., 800 F., 10 mm. Hg).' The haze of the feed was 70 F.; the product had a haze of 45 F.

A 3070% overhead cut (905 to 980 F. boiling range) was also sieve treated at the same conditions. The feed had a haze of 60 F.;'the product had a haze of 25 F.

This shows that:-(1) material boiling over 1000 F. cannot be sieve dehazed to 35 'F., (2) material boiling below 980 (later extended to 1000 F.) can be sieve treated to less than 35 F. haze.

EXAMPLE 5 An experimental run yielding a lube oil product of less than 30 F. haze temperature from an initial oil feed having a haze point of 75 F. will now be described. The initial oil was the lube oil denoted 900X (its properties being indicated in Table 2). The oil was fractionated at 660 F. at 10 mm. of mercury to yield a fraction boiling at or above 1000- F. and a fraction boiling below 1000 F. (at atmospheric pressure). The former fraction represents 20 volume percent of the initial lube oil feed, the-remaining 80 volume percent being recovered in the latter fraction.

The material boiling under 1000 F. was then subjected to adsorption by 5 A. molecular sieves. The adsorption zone operated in the liquid phase at a'temperature of 650 F. and pressure of 400 p.s.i.g. An oil feed rate of /3 w./w./hr. was employed for about 40 to 55 hours at which time the adsorption run was stopped. The cities of the sievate product of the adsorption treatment are set forth below in Table 3.

The heavy fraction (1000 F. was subjected to dewaxing. Dewaxing was effected at -20 F., 4 parts by weight of solvent (60% methyl ethyl ketone, 40% toluene) being employed per part of heavy oil. After dewaxing, the oil was separated from the solvent. Properties of the dewaxed oil are given in Table 3.

, The sievate product and the dewaxed oil were then combined. Table 3 sets forth the resulting final lube oil product.

Table 3.-il properties Blend of Slevate Dewaxed Oil Sievate l and Dewaxed Oil Gravity, API 25. 5 Approx. 25.0.- 25.3.

Flash, F 440 Approx. 700 470.

Sulfur, Wt. percent 0.03 Approx. .10 less than 0.06. Pour Point, 5 l0.

Haze Point, F 30 0 less than 30 F.

I Viscosity index of 70.

- high boiling fraction to solvent dewaxing in a dewax'ing zone so as to remove haze producing normal parafiins and non-normals from said high boiling fraction, withdrawing dewaxed oil product from said dewaxing zone; subjecting at least a portion of said low boiling fraction to treatment with molecular sieve adsorbents in an adsorption zone, said molecular sieve adsorbents adsorbing haze producing,- normal parafiins from said fraction, withdrawing non-adsor-bed oil from said adsorption zone; and commingling said solvent-dewaxed oil and said non-adsorbed oil to form a lubricating oil of lowhaze point. 2. The method of claim 1 wherein said molecular sieve adsorbents are of the 5 A. type, and said adsorption zone operates at a temperature of 600 to 700 F. and a pressure of 0 to 500 p.s.-i.g'.

3. The method of'claim 1 wherein hydrocarbon oil is derived from a naphthenic crude and said lubricating oil 7 product has a maximum haze point of 35 F.

4. The method of claim 1 wherein said high boiling fraction is at most 20 volume percent of said hydrocarbon oil. 3

5. A process 'for yielding a lubricating oil having a maximum haze point of 35 R, which comprises; segregating a feed hydrocarbon oil of undesirable haze'point characteristics into a high boiling fraction boiling above about 1000 F. at atmospheric pressure and a low boiling fraction boiling below 1000 F. at atmospheric pressure; removing haze-producing non-normal hydrocarbons from said high boiling fraction by subjecting it to solvent dewaxing by a suitable solvent in a treating zone, withdrawing dewaxed oil from said treatin zone; removing haze-producing, norm-alparaflins from said low boiling fraction by contacting at least a portion of said low boiling fraction with molecular sieve adsorbents of the 5 A. type in an adsorption zone, withdrawing un adsorbed oil from said adsorption zone; and mixing said solvent-dewaxed oil and said un-adsorbed oil to form a lubricating oil of desired haze point.

6. The process of claim 5 wherein said high boiling fraction comprisesa maximum of 20 volume percent of said feed hydrocarbon oil. i

7. The process of claim 5 wherein said adsorption zone operates under liquid phase conditions at temperatures of 600 to 700 F. and pressures of 0 to 500 p.s.i.g.

8. The process of claim 5 wherein said solvent is selected from the group consisting of propane, methyl ethyl ketone, and toluene.

References Cited in the file of this patent g OTHER REFERENCES Barrer: Transactions of the Farraday Society, vol. 40 (1944), London, page 214 and FIG. 9(a).

Barrer: Quarterly Reviews of the Chemical Society, vol. III (1949), London, page 502. I

Claims (1)

1. AN IMPROVED METHOD OF PRODUCING A LUBRICATING OIL OF LOW HAZE POINT FROM A HYDROCARBON OIL WHICH COMPRISES: SEGREGATING SAID HYDROCARBON OIL INTO A HIGH BOILING FRACTION BOILING PREDOMINANTLY ABOVE ABOUT 1000*F. ATMOSPHERIC PRESSURE AND A LOW BOILING FRACTION BOILING BELOW 1000*F. AT ATMOSPHERIC PRESSURE, SUBJECT SAID HIGH BOILING FRACTION TO SOLVENT DEWAXING IN A DEWAXING ZONE SO AS TO REMOVE HAZE PRODUCING NORMAL PARAFFINS AND NON-NORMALS FROM SAID HIGH BOILING FRACTION, WITHDRAWING DEWAXED OIL PRODUCT FROM SAID DEWAXING ZONE, SUBJECTING AT LEAST A PORTION OF SAID LOW BOILING FRACTION TO TREATMENT WITH MOLECULAR SIEVE ABSORBENTS IN AN ADSORPTION ZONE, SAID MOLECULAR SIEVE ADSORBENTS ADSORBING HAZE PRODUCING, NORMAL PARAFFINS FROM SAID FRACTION, WITHDRAWING NON-ADSORBED OIL FROM SAID ADSORPTION ZONE, AND COMMININGLING SAID SOLVENT-DEWAXED OIL AND SAID NON-ADSORBED OIL TO FORM A LUBRICATING OIL OF LOW HAZE POINT.

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