CA1057685A - Process for the conversion of hydrocarbons - Google Patents

Abstract

A B S T R A C T

A process for the preparation of lubricating oils with high viscosity index by contacting a mixture of heavy hydrocarbons consisting at least partially of one or more foots oils (a foots oil being a mixture of oil and low-melting paraffin waxes obtained during the de-oiling of slack wax in the preparation of distillate paraffin wax) with a hydrocracking catalyst at elevated temperature and pressure and in the presence of hydrogen.

Description

. 2 ~L~57G8S

'rhe pre-sent invention relates to ca process ~or the preparation ~f lukri~itin~- oi.ls ~lith hi~h visco~,ity index by the catalytic ~drccrackin~ of a.rnixture of hravy hydroca.rbons, and to lubricatin~ oils thus obta.ined.
For the preparation of lubricating oils with high viscosity index, which among other purposes can be used as base oils for ;.
multi-grade lubricating oils, there are in princi.ple two routes availabl.e, v~z.: the conventional route and ~he hydrocracking route, - ~;~
both of which are used on a commercial scale. :~`
The preparation of lubricating oils with high viscosity index by conventional means is carried out as follows.~.
A waxy crude oil is separated by distillation at atmospheric .:.
. pressure into a number of distillate fra.ctions (to be specific~
one or ~ore gasoline fractions, Xerosine fractions and light gas oil fractions in that order) and a residue (known as the long I residue) This long residue is then separated by disti.llation ; under reduced pressure intc, a number of distillate fractions Z (to be specific: one or more heavy gas oil fractions, spindle ;~:
I oil fractions, li~ht machine oil fractions and medium heavy ,~. 20 machine oil fractions in that order) and a residue (known as the short resldue). From the lubricating oil fractions obtained during the distillation under reduced pressure the correspondin~
lubricating oils are prepared by re~ining. The refining of the ~, spindle oil fractions, li~t machine oil fractions and medium '! 25 heavy machine oil l~ractions is achieved by removal of aromatlcs .~ and paraffi.n waxes from these fractions. ~he removal of aromatics and pa.ra.ff.in waxes from the lubricatirlg oil fractions can be ,! ~

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~13 57G8S

carried out in random sequence. In order to keep the volume of oil to be dewaxed as small as possible, it is preferable to ; first remove the aromatics and then the parafin waxes. In this ~ ~
; manner the corresponding wa~y raffinates and subsequently the ~ ~;
corresponding finished lubricating oils are prepared from the spindle oil3 light machine oil and medium heavy machine oil waxy distillates. In the refining of the short residue~ asphàlt is initially removed from the residue. Aromatics and paraffin ~ ;
waxes are then removed from the de-asphalted oil thus obtained.
~i 10 In this manner first the brightstock waxy raffinate and subse-`1 quently the finished brightstock are obtained from the de-asphalt- ;
ed oil. The paraffin waxes obtained during the refining of the various lubricating oil fractions are referred to as slack wax.
! The preparation of lubricating oils by hydrocracking is t carried out as follows. A heavy fraction of a waxy crude oil, - such as a vacuum distillate, a de-asphalted oil or a distillate ~: .
~ of a residual slack wax is passed over a suitable hydrocracking ,"!' catalyst at elevated temperature and pressure and in the presence of hydrogen. One or more lubricating oil fractions are separated by distillation from the hydrocracked product.
From the lubricating oil fractions thus obtained the ;xl correspondlng lubricating oils are prepared by removal o-f paraffin waxes from these fractions. Just as in the con-ventional preparation of lubricating oll~ the paraffin waxes 1 obtained during the preparation of lubricating oil by hydro-`~ cracking are referred to as slack waxO
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~05r76~i The dewaxing of lubricating oil fractions can be effected by cooling, upon which the paraffin waxes s~para~e out as solids and can be filtered off. The dewaxing is preferably carried out by cooling in the presence of a solvent~
Suitable sol~ents for this purpose are, among others, mixtures of a ketone such as acetone~ methyl ethyl ketone or methyl iso~
butyl ketone ~ith an aromatic compound such as ben~ene, toluene or xylene. In practice large-scale use is made of a mixture of methyl ethyl ketone and toluene for this purpose~ The dewaxing of lubricating oil fractions in the presence of a solvent is effected by mixing the waxy lubricating oil fraction with the so~vent and heating the mixture to a temperature that is about 20-30 C higher than the temperature that is necessary for the complete dissolving of the paraffin waxes. The solution is then slowly cooled to the filtration temperature, which is ~;
generally about -20 to -30C.
After washing the fllter cake with solvent that is at the filtration temperature and removal of the solvent from the filtrate and the filter cake the dewaxing is ready~ In ~ ~
this way~ in addition to a dewaxed lubricating oil~ a slack `
wax is obtained which latterg in addition to a mixture of paraffin waxes with various structures and melting points~
I still contains a considerable quantity of oil. Distillate I paraffin waxes and residual paraffin waxes are prepared from this slack wax by de_oiling. `
Distillate paraffin wax is prepared by de-oiling of slack wax obtained during the dewaxing of light and medium hea~y `

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distillate lubricating oil fractions. Residual paraffin wax is principally prepared by de-oiling of slack wax obtained during the dewaxing of residual lubricating oi], fractions.
On the basis of their composition, residual paraffin waxes are differentiated into ~P wax and microwax The de-oiling of ~lack wax in the preparation of dis-tillate paraffin wax can be effected by melting the slack wax~
casting the melt in a thin layer and cooling ~he latter slowly so that the slack wax solidifies again. By slowly heating up the solid mass~ ~he paraffin waxes with the lowest melting points melt and dissolve into the oil that is present as free oil between the paraffin wax crystals. This causes the liquid content of the solid mass to rise. Eventually the liquid content of the solid mass reaches such a level that the liquid can no longer remain adsorbed between the paraffin wax crystals and separates from the solid mass. This sweating, as it is knowng of the slack wax is continued until'the remaining paraffin wax (distillate paraffin -~
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wax) has the desired low oil content. Since low-melting point paraffin waxes - rich in branched paraffins - are removed along with the oil~ the remaining distillate paraffin wax has a lower '' branched paraffin content than the original slack wax. The ,,, mixture of oil and low-melting point parafin waxes obtained during the de-oiling of slack wax in the preparation of I distillate parafein wax is reerred to as foots oil.
,1 ~ The de-oiling of slack wax in the preparation of res-idual paraffin wax is effected in the presence of a solvent.
~1, This method is also very suitable for ~he preparation of distillate ' :' " . ;
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paraffin wax. Thc same solv~nts can be used for de-oiling as are used for the dewaxing of lubricating oil fractions.
Just as in dewaxing~ for de-oiling large-scale use is made in practice of a mixture of methyl ethyl ketone and toluene.
The de-oiling of slack wax in the presence Qf a solvent in the preparation of distillate and residual paraffin wax is effected by miæing the slack wax with the solvent, heating ~he mixture until the waxes have dissolved and then slowly cooling the mixture to the filtration temperature. After washing the filter cake with solvent that is at the filtration temperature and i removal of the solvent from the filtrate and the filter cake de-oiling is ready. In this way, in addition to a distillate or residual paraffin wax~ a foots oil is obtained which latter con-tains a mixture of paraffin waxes in addition to the oil origin-ally present in the slack wax. If the de-oiling is used for the preparation of distillate paraffin wax from slack wax~
the mixture of paraffin waxes present in the foots oil consists .i , , largely of low-melting point branched paraffins. If the de-oiling :, :
is used for the preparation of residual paraffin waxes~ the ; 20 mixture of paraffin waæes present in the foots oil consists largely of low-melting-point branched paraffins and cyclo-i paraffins.
, The de-oiling of slack wax can be carried out in two stages, it being possible to obtain two different qualities `
of paraffin wax from one slack waæ. For this purpose either the para~fin wax or the filtrate from the de-oiling must be subjected to an additional treatment. Using the route in 6~

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- 7 ~ 105'~6~i ~l~ic~ t~e paraffin waxes are ~ubjected to an additional process, the de-oilin~ ol the slack wax with solvent is e~fected in the first stage of the process at a lower temperature and the treatment of the separate~ paraffin wax with solvent in the second stage of the process at a hi~her temperature.
At this higher temperature only part of the paraffin wax crystallizes out. The lower-melting point paraffin wax can be produced from the filtrate from the second stage by removal of the solvent. In this process the foots oil is isolated from the filtrate of the first stage by removal of the solvent.
Using the route in which the filtrate f`rom the de-oiling is subjected to the additional treatment~ the de-oiling of the slack wax is effected with solvent in the first stage of the process at a higher temperature. In this case only the higher-melting point paraffin wax crystallizes while the lower-melting point ~; paraffin wax remains in the filtrate. If the filtrate from I the ~irst stage is cooled to a lower temperature~ the lower-melting point paraffin wax separates out. In this process the foots oil is produced from the filtrate of the second stage by removal o~ the solvent. Fractionated de-oiling is used on a large-scale in practice for the preparation of both HMP wax ; and microwax from a slack wax derived from a residual .. . .
! lubricating oil fractlon.

`, The foots oil referred to on a number of occasions in the foregoing, which is obtained in considerable quantities 3 as a by-product Or the preparation on a commercial scale of `~

I di~tillate and residual paraffin wax by de-oiling of slack wax, ., t7~

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has so far been used as a blending component in fuel oil and in feeds ~ -for catalytic cracking plants~ Where mention is made of foots oil ln this patent application this shall be understood to mean a mixture of - -oil and paraffin waxes obtained as a by-product in the preparation of ..
distillate or residual paraffin wax by de-oiling of slack wax.
It has now been found that foots oil as such or ln mixtures with other heavy hydrocarbon fractions is particularly suited to serve as starting material for the preparation of lubricating oils with high ` viscosity indexes by catalytic hydrocràcking.
; 10 The present invention therefore provides a process for the preparation of lubricating oils with high viscosity index by the hydro-, cracking of a mixture of heavy hydrocarbons, characterized in that amixture of heavy hydrocarbons consisting at least partially of one or more foots oils (a foots oil being a mixture of oil and paraffin waxes obtained as a by-product in the preparation of distillate or residual t paraffin wax by de-oiling of slack wax) is contacted in the presence of hydrogen with a catalyst that contains one or more metals of Group VIB, VIIB or VIII supported on a carrier composed of one or more oxides of elements of Group IT~ III or IV, at a temperature of 325C-450C, a , 20 pressure of 10-250 bar, a space velocity of 0.2-5.0 kg of feed/l of `~ ;
catalyst/hr and a hydrogen/feed ratio of 100-5000 Nl hydrogen/kg of feed.
If for the preparation of lubricating oils according to the invention a feedstock is used that is obtained by mixing one or more foots oils with one or more other heavy hydrocarbon fractions, , for this purpose use is preferably made of heavy hydrocarbon fractions j selected from the group formed by `l a) waxy lubricating oil fractions obtained during the distillation 1 ~ ~

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- 9 ~ S'~5 under reduced pressure of atmospher:ic distillation residues of waxy crudec~
b) sla.ck waxes that have been separated from the waxy lubricating oil fractions referred to under a), ~, 5 c) slack waxes that have been separated from waxy lubricating oil fractions obtained by hydrocracking, and d) mixtures Or two or more of the heavy hydrocarbon fractions referred to under a), b) a,nd c). Examples of' such heavy hydrocarbon fractions are spindle oil, light machine oil and medium heavy , , 10 machine oil waxy distillates and de-asphalted oils, the corresponding : . ~
waxy raffinates that have been obtained from the above-mentioned ,:
lubricating oil fractions by processingr with a. selective solvent for aromatics such as furfuralS a,nd the corresponding slack ~: waxes that have been obtained from the above-menti.oned 1ubri.cating ~ ., ' 15 oil fractions by dewaxing. Mixtures of one or more distillate ,l lubricating oi]. fractions and/or one or more residual lubricating ;' oi.l fractions and/or one or more slack waxes ca.n also very suita.bly be used together with one or more foots oils as starting materia.l ~' ~ for the ~reparation of lubricating olls with high viscosity index ,`, 20 according to the invention.
! If for the preparation of lubricating oils according , ~, to the invention a mixture of two or more .foots oils is used , ! .
~, as feedstock, use can very suitably he made of foots oils -~ that have been obtained by dewaxinÆ and slack wax de-oiling from ~ ,' :~, 25 lubricating oi,l fractions the boi.ling ranges of which are substantially similar or substantiall.y contiguous to each other. Thus, for example, use can very suitably be made of ` ~"`

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Y~35 : -a mixture of foots oils that have all been obtained from light and/or medium-heavy distillate lubricating oil fractions or from heavy distillate and/or residual lubricating o:il fractions by dewaxing and slack wax de-oiling. A similar situation applies if for the preparation oP lubricating oils according to the inve~tion a feedstock is used that has been obtained by mixing one or more foots oils with one or more other heavy hydrocarbon fractions. As blending components for th~ foots oils use can very suitably be ~ade of lubricating oil -fractions or slack waxes obtained ~herefrom by dewaxing, which lubricating oil fractions have a boiling range that is substantially similar or substantially ~ -contiguous to the boiling range of the lubricating oil fractions from which the foots oils were obtained by dewaxing and slack wax de-oiling. Thus~ for example~ one or more foots oils obtained by dewaxing of light and/or medi~n heavy distillate `~
lubricating oil fractions and slack wax de-oiling can very suitably be mixed with one or more light and/or medium~heavy distillate ~;
lubricating oil fractions or with one or more slack waxes ob_ !1 tained therefrom by dewaxing. One or more foots oils obtained by dewaxing;of heavy distillate and/or residual lubricating oil fractions and slack wax de-oiling can also very suitably be . mixed with one or more heavy distillate and/or residual lubri-- cat mg oil fractlons or with one or more slack waxes obtained therefrom by dewaxing.
A very suitable starting material for the preparation of lubricating oils according to the inventlon is a mixture of one or more foots oils and one or more slack waxes, both the foots oils and the slack having been obtained from lubricating oil ; ", , , ., . , ~ , . , ,;, , .. ,. ,, .. .. .. ... -: , ~

~V576~35i rractions the boili.n~ ranges of whi ch are substan~,ially simi.lar or subst;)n~ially contig~ous to each other.
When USill~r a mixture o.~ one or more foots oils with one or more s1.ack waxes as starting materi.al for the preparation Or lubricatin~ oi.ls according to the invention, it may be advantageous :
for the mixture to be partially composed of one or more foots oils and/or slack waxes derived from lubricatin~, oil fractions that have been prepared by conventional methods, the remainder comprisin~
one or more foots oils a.nd/or slack waxes derived from lubricatin~
oils fractions that have been obtained by hydrocracking. An example . of such a starting material is a mixture consisti.ng of the . followin~ five components:
~ a) a foots oil obtained by de-oiling a bri~htstock slack wax y which latter was prepared by dewaxin~ a brightstock waxy raP~i~ate, , 15 b) a slack wax obtained by dewaxing a lubricating oil ~raction, i~ which latter was prepared by hydrocracking a de-asphalted oil, ~.
!~ c) a slack wax obtained by dewaxing a brightstock waxy raffinate, ~ d) a.slack wax obtained by dewaxing a lubricating oil fraction i which latter was prepared by hydrocracking a medium heavy machine :~
oil waxy distilla.te, and , e) a slack wax obtained by dewaxin~ a. medium-heavy machine oil waxy distillate.
For the preparation of lubricatin~; oils according to J
the invention use is ~4~ made of a catalyst that contains one or more meta1s of Groups VIB, VIIB and/or VIII supported I on a carrier composed of one or more oxides of elements of ¦ Groupg II, III and/or IV, ~xamples of ~uitable metals are :J . ~ :~
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nickel, cobalt, molybdenum and tungsten. Preference is ~iven to catalysts that contain at lea;t one metal that has been sclected from the group comprisi.rlg ni.ckel a.nd ~obalt and at least one metal that has been selecteci from th~ ~roup compri.sing ~olybdenum and tun~sten. The metals may be present on the carrier as such or as metal oxides or metal sulphides.
The catalysts a.re preferably used in the sulph;dic form. :.
Sulphiding of the catalysts may be ef~ected accordin~ to any process known in the art for sulphiding catalysts, for ~;
example by contacting the catalyst with a mixture of hydrogen ;:.
and hydrogen sulphide or with hydrogern and a sulphurous ~
hydrocarbon oil such as sulphurous gas oil. ~ ~:
Examples of suitable carriers for the catalysts that may be used according to the present invention are silica, alumina, zirconia and magnesia; a.nd also mixtures of these oxides, such as silica-alumina, silica~ma~nesia and silica-zirconia. Preference is given to catal.ysts that contain alumina .
as carrier materia.l.
Catalysts are used according to the present inventîon ~ :
may also contain promotors such as fluorine, boron and/or phosphorus. Fluorine may be incorporated into the catalysts -durin~ any sta~e of the catalyst preparat.;on. Fluorine may also be incorporated into the catalysts by fluoriding the la.tt.er in situ. In-situ fluoriding of the catalysts may be effected by adding, during the initial phase of the hydrGcra.cking process, a certain quantity of a fluorine compound ko the gas and/or liquid stream that is passed over the catalyst, e .

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S~ 5 ~ntil the required ~luorl ne content of the catalyst is attained For the preparation of lubr;cating oils according to the invention one of the rollowing t~o type~ of catalyst is preferab]y used (A and ~):
A. A f]uorine-containing nickel-tungsten catalyst on alumina as carrier, which catalyst has a compacted bulk density o~
at least o.8 g/l, contains at least 3 parts by weight ~;
of nickel and 20 parts by weight of tungsten, respectively, per 100 parts by weight of carrier and has been prepared as follows from an alumina hydrogel from which, by drying `` and calcining, a xerogel with a compacted bulk density of less than o.8 g~ml can be obtained:
1) If the pore volume quotient (as defined herein after) of the said xerogel is at least 0.5, the preparation of the catalyst takes place either a) by drying and calcining the alumina hydrogel, incorporation of the metals and, if desired, fluorine into the xerogel, and drying and calcining of the composition, or b) by incorporation of the metals andj if desired, ~luorine into the alumina hydrogel and drying and calcining of the com-J position.

2) If the pore volume quotient of` the said xerogel is less than 0.5, the preparation of the catalyst takes place by ~j 25 incorporation of the metals and at least part of the fluorineinto the alumina hydrogel and drying and calcining of the ~ composition provided that in the latter case fluorine is .

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s incorporated :into the alumina hydroge:L in sufficient quantity that from this f1uorine-containing alumina hydrogel a xerogel with a pore volume quotient of at least 0.5 can be obtained ;
by drying and calcining.
In this patent application by the pore volume quotient of a material shall be ~derstood the ~uotient of the mercury pore volume and the total pore volume,.of the matericil, the mercury pore volume being defined as the pore volume present in pores with a diameter greater than 7.5 nm determined with mercury and the total pore volume being defined as the to~al of the pore volume present in pores wi.th a diameter of less than 60 nm deter- ~
mined with nitrogen and the pore volume present in pores with.a ~ ;
diameter of at least 60 nm determined with~mercury.
B. A fluorine-containing nickel-tungsten catalyst on a carrier in ~hich catalyst at least part of the fluorine has been incor- ~:
i - porated by in-situ fluoriding. ::
¦ The hydrocracking of foots oils or of a mixture of one --j or more foots oils with one or more other heavy hydrocarbon frac-- .
.~ tions in the preparation of hlbricating oils with high viscosity index according to the invention is effected by contacting the feed at elevated temperature and pressure and in the presence of hydrogen with the catalyst, which is preferably present in one or `l , i more beds of particles with a si~e of between 0-5 and 3 mmO
~ Suitable hydrocracking conditions are~ a temperature of ~ --} 325-450 C, a pressure from 10 to 250 bar, a hydrogen/feed ratio j of 100~5000 N1 hydrogen per kg of feed and a space velocity -~
~ of 0.2-5 kg of feed/l of catalyst/hour. It is preferably to use ;~

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the following conditions: a temperature of 350-425C~ a pressure of 40-200 bar, a hydrogen/feed ratio of 500~2500 Nl hydrogen/kg of feed and a space velocity of 0.5-1.5 kg of feed/l of catalyst/hourO
Lubricating oils prepared according to the inven~ion have a low aromatic content. Lubricating oils with an even lower aromatic content can be prepared according to the invention if the hydrocracking step is followed by a hydro- ;
finishing step~ Hydrofinishing of the hydrocracked product can be carried out by contacting the hydrocracked product at elevated temperature and pressure and in the presence of hydrogen with a hydrofinishing catalyst. The pressure, space velocity and gas velocity that are used in the hydro-finishing step may be selected within the same limits as give above for the hydrocracking step. The hydrofinishing ~-temperature is preferably selected between 225 and 400C and particularly between 275 and 375 C. The temperature applied in the hydrofinishing step should be at least 25C lower than the temperature at which the hydrocracking step is carried out.
Suitable hydrofinishing catalysts are catalysts that contain one or more ~etals of Groups VIB~ VIIB or VIII on a carrier.
The effluent from the hydrocracking reactor~ or~ if hydrofinishing is usèd, the effluent from the hydrofinishing r0actor~ is cooled and separated into a hydrogen-rich gas and a liquid product. The liquid product comprises hydrocarbons ~-that boil below the boiling range of lubricating oils and ;~
hydrocarbons that boil within this range. The hydrocarbons j ~` "
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.1 ~ ~ ~t~ ~ 8 that boil below the said range are separated from the higher ~ , boiling residue, preferably by fractiona], distillation. The cutting point of this distillation is preferably selected such that the higher boiling point residue has an initial boiling point :in the region of 350-550C. In addition to ~ ;
excellent lubricating oil components3 this residue generally contains paraffin waxes that solidify at ambient temperature and therefore adversely affect the pour point of the lubricating oil. ~ ~' In order to obtain a suitable lubricating oil from the residue, it is therefore preferable to dewax this residue. The dewaxing process may be effected in any desired manner. The dewaxing is preferably carried out with a mixture of methyl ethyl keton~ and toluene , at a temperature between -10 and -40C and a solvent/oil volume ratio between 1 : 1 and 10 : lo In order to increase ! the yield of lubricating oil it is preferable to recirculate at least part of the separated paraffin waxes to the hydro~
~ cracking reactor.
Il The invention will now be elucidated by reference to '-~, the following Examples. In these Examples use was made of ~ 20 three feeds (I-III) and two catalysts (A and B).
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FEED I
; Oil obtained by de-asphalting a residue derived from the 'l distillation under reduced pressure of an atmospheric diStillation residue of a Middle East crude. This de-asphalted oil had the following properties:
VI after dewaxing at -30 C: 77 sulphur content: 201% by wt.
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~ nitrogen content: 630 ppmw. , ' '' -16-:. , - 1 7 ~ 7~85 FEED II
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Foots oil obtained by de-oiling a brightstock slack wax.
The slacl~ wax was prepared starting from the de-asphalted oi]
described above as f~eed ~ by ex~!raction with rurfural rol]owed by dewaxing of the brightstock waxy raffinate with a mixture of methyl ethyl ketone and toluene at a temperature of -20C. The yield of brig,htstock slack wax was 15~ by weight expressed in terms of de-asphalted oil. The de-oiling of the bri~htstock slack wax was carried out in two stages usin~
a mixture of methyl ethyl ketone and toluene as solvent.
In the first stage of the de-oi~ing process the slack wax was dissolved in the solvent at elevated temperature and the mixture was then cooled to 42C, The crystallized HMP wax was then washed with so]vent of 42C and the solvent was removed from the HMP wax. In the second stage of the process the filtrate from the first stage was cooled to 11C.
The crystallized microwax was washed with solvent at ll~C
and the solvent was removed from the microwax. The foots oil was obtained from the filtrate of the second stage by removal ~, 20 of the solvent~ In this manner 100 parts by weight of bri~,htstock sIack wax yielded:
11 parts by wt of EIPM wax with a setting point oE
86,5C, 40 parts by wt of microwax with a settin~ point ~ 25 of 58~C, and ¦ 49 parts by wt of foots oil.
I This foots oil had the following properties:

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~ L)S7~1!35 nitrogen content: 214 ppmw sulphur content: o.8s% by wt paraffin wax content (deter-mined at -30 C3: 62.5% by wt Oil content (determined at _30C): 37.5% by wt This oil had the following properties~

V ". ', ' k210 35.3 cS
VI: 101 ~ ~
Pour point: -20 C ~ ~`
FEED III
A mixture with the following composition~
12.5% by wt of foots oil ;
3205% by wt of slack wax obtained during the dewaxing of a lubricating oil that was prepared by hydrocracking a, de-asphalted oil ~ ;
9% by wt of slack wax obtained during the dewaxing of a brightstock wax~ raffinateO 17.5% by wt of slack wax ~ `
, i obtained during the dewaxing of a lubricating oil that was prepared by hydrocracking a medium-heavy machine oil wax~ distillate.
28.5% by wt of slaok wax obtained during the dewaxing - ;
of a medium-heavy machine oil waxy raffinate.
This mixture had the following properties~
nitrogen content: 32 ppmw sulphur content: 0.3i~0 by wt `~
~i paraffin wax content (determined at s _30C): 69.o% by wt `~
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6~35 oil content (determined at -30 C): 31~0% by wt This oil had the following properties: ~ f Vk210: 23.5 cS
VI: 99 pour point: -21C
The foots oil included in thi.s mixture was prepared by de-oiling a brightstock slack wax obtained during the i;
dewaxing of a brightstock waxy raffinate from a Middle East crude. The de-oiling was carried out in two steps in the same manner as described for the preparation of the foots oil used as ~eed II. In this manner lO0 parts by weight of brightstock slack wax yielded~
9 parts by wt of HPM wax with a setting point o~
86.5C~
35 parts by wt of microwax with a setting point of 58Cj and ;"~
~ 56 parts by wt of foots oil~
,~ Thi foots oil had the following properties~
nitrogen content- 130 ppmw sulphur content: 1.04% by wt I ~B paraffin wax content (determined fj at -30 C): 4401% by wt oil content (determined at -30C): 5509% by wt - This oil had the following properties~

k ~ ~ i 210: 36.o cS

1~ YI: 99 iff Pour point- -21 C

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CATALYST A
This catalyst, which contained 37 parts by weight of nickel 70 parts by weight oftungSten and 14 parts by weight of fluori~e per 100 parts by weight of alumina, carrier and had a compacted bulk density of 1.2 g/ml, was prepared starting from an alumina hydrogel from which a xerogel could be obtained with a compacted bulk density of 0.35 g/ml and a pore volume quotient of o.8 by drying and calcining. The preparation was efected by mixing ;
an aqueous solution that contained a nickel compound, a tungsten compound and a fluorine compound~ with the alumina hydrogel and keeping the mixture at elevated temperature for some time~
separating the hydrogel loaded with metals and fluorine from the mixture and subsequently drying, extruding and calcining ~`
the hydrogel.
CATALYST B
This catalyst, which contained 10 parts by weight of ~` :
nickel, 20 parts by weight of mo~enum~ 2 parts by weight of phosphorus and 2.5 parts by weight of fluorine per 100 parts by weight of carrier, was prepared by impregnating an alumina carrier with an aqueous solution that contained a nickel ;~
compound~ a mo~d~num compound and a phosphorus compound~
followed by drying and calcining the composition. FluDrine was incorporated into the catalyst by in situ fluoriding.

Catalyst A was used for the preparation of lubricating oils with high viscosity index by hydrocracking feeds I
and IIo The catalyst was used in s`ulphided formO The ~ 21 -~ 057~35 sulphiding of the catalyst was carried out by contacting the latter for 5 hours with a mixture of hydrogen and hydroger. sulp~ide in a ratio by vol,ume of 7 : 1 at a tc~perature between 75C and 375C and a pressure ol' 10 bar.
The catalyst was used in th~ form of 1.5 mm extrudates. The , hydrocracking was carried out under the follo~rin~ conditions:
~ hydrogen partial pressure 150 bar ,~ space velocity: 1 l.l l,hr 1 hydrogen/feed ratio: 2000 Ml.l 1 ;
Thç results of these experiments a,re given in Table A.
TabI _A
, Ex~eriment No. 1 2_ ~ 4 ~ Feed ~ , I II II II
'', H~drocra_kin~ tem~erature~ C 410 380 385 395 ~-~ Yield of 390C fraction `' based, on feed~ % b~ wt__ _ ___ __8. 1~I __22.____ __50 0 Prop~,rties of the 390C
~raction after dewaxin~ at -30C ~,~

~! Yield based on feed, ;, % by wt 3 36.6 39.5 3~.0 ' 'j'! k210~ Cs 14.9 12.4 B.5 ~ , , VI 140 124 127 l4n , ' Pour point, C -18 -18 -20' -21 ;' ,, _____________________________~____ -----------------------'!--------- l '', Experiments 2, 3 and 4 shown in ~able A are experiments ~"
~l according to the invention. Experiment 1 ~alls outside t,he ' '~ scope of the invention and has been included for comparison.

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~ comparison of the results of experiments 1 ~nd 4 shows that foots oils is a more attractive base material for the preparation of lubricating oils with high viscosity index by hydrocracking than the de-asphalted oil from which this foots oil has been derived. In both cases a lubricating oil is obtained with a viscosity index of 140; however, when foots oil is used as feed~ a higher yield of this lubricating oil is obtained and moreover the lubricating oil has a higher ;
viscosity.
From the results of experiments 3 it is apparent that the product obtained has a higher oil content than the feed used as starting ~aterial, while the viscosity index of the oil in the product ~VI 127) is 26 points higher.
An even higher viscosity index is obtained accordiMg to experiment 4 ¦VI 140)~ but at the expense of a small loss in yield. A comparison of the results of experiments 2 and 4 shows the advantage of the higher hydrocracking temperature. In both experiments approximately the same yield of lubricating oil is obtained; the lubricating oil prepared at the higher hydrocracking temperature, however, has a VI that is 16 points higher.
E~AMPLE II
Catalysts A and ~ were used for the preparation of lubricating oils with high viscosity index by hydrocracking feed III. The conditlons relatin~ to sulphiding of the catalysts were the same as given in Example 1. The hydro~
cracking was carried out under the following conditions~

-22- ~

`:
. .

hydrogen partial pressure: 130 bar space velocity: 1 ~g.1. l.hr-1 Hydrogen/feed ratio: 1500 Nl.kg 1 The catalysts were used in the form of 1.5 mm extrudates. .
In-situ fluoriding of catalyst B was effected by adding 300 ppmw of fluorine as ortho-fluorotoluene to the feed during the initial phase of the experiment until the required fluorine content of the catalyst was attained.
The results of these experiments are given in Table Bo - . ~ . ~, . , . , , . :

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O H ~ i-' ~ O I tD

~' f! 1~
c~O ~ Dq ~ t ~
~b ~

3 ~ g o ~ ~ , lo .
$~ lw lo ~:

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. ~ .:

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~L~VS fi'~35 The results of experiments 5-10 given in Table B show the suitability o~ foots oil as a component in a mixture of heavy , hydrocarbons from which lubricating oils with high viscosity ~ -index can be prepared by catalytic hydrocracking.
A comparison of the results of experiments 6 and 9 shows ~hat catalyst A is more suited to the present purpose than catalyst B. In both experiments a lubricating oil is obtained with substantially the same viscosity and viscosity index. When using catalyst A~ however, a higher yield of this ~, lubricating oil is obtained and moreover at a lower hydro-cracking temperature.

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Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of lubricating oils with high vis-cosity index by the hydrocracking of a mixture of heavy hydrocarbons, char-acterized in that a mixture of heavy hydrocarbons consisting at least par-tially of one or more foots oils (a foots oil being a mixture of oil and paraffin waxes obtained as a by-product in the preparation of distillate or residual paraffin wax by de-oiling of slack wax) is contacted in the presence of hydrogen with a catalyst that contains one or more metals of Group VIB, VIIB or VIII supported on a carrier composed of one or more oxides of ele-ments of Group II, III or IV, at a temperature of 325°C-450°C, a pressure of 10-250 bar, a space velocity of 0.2-5.0 kg of feed/l of catalyst/hr and a hydrogen/feed ratio of 100-5000 N1 hydrogen/kg of feed.

2. A process as claimed in claim 1, characterized in that the mixture of heavy hydrocarbons comprises a mixture of two or more foots oils that have been obtained from lubricating oil fractions the boiling ranges of which are substantially similar or substantially contiguous by dewaxing and slack wax de-oiling.

3. A process as claimed in claim 1, characterized in that the mixture of heavy hydrocarbons comprises a mixture of one or more foots oils with one or more other heavy hydrocarbon fractions selected from the group formed by a) waxy lubricating oil fractions obtained during the distillation under reduced pressure of atmospheric distillation residues of waxy crudes, b) slack waxes that have been separated from the waxy lubricating oil frac-tions referred to under a), c) slack waxes that have been separated from lubricating oil fractions ob-tained by hydrocracking, and d) mixtures of two or more of the heavy hydrocarbon fractions referred to under a), b) and c).

4. A process as claimed in claim 3, characterized in that the mixture of heavy hydrocarbons comprises a mixture of one or more foots oils and one or more lubricating oil fractions or slack waxes obtained therefrom by de-waxing, which lubricating oil fractions have a boiling range that is substan-tially similar or substantially contiguous to the boiling range of the lub-ricating oil fractions from which the foots oils were obtained by dewaxing and slack wax de-oiling.

5. A process as claimed in claim 4, characterized in that the mixture of heavy hydrocarbons comprises a mixture of one or more foots oils and one or more slack waxes.

6. A process as claimed in claim 3, 4 or 5, characterized in that the mixture of heavy hydrocarbons is partially composed of one or more foots oils and/or slack waxes derived from lubricating oil fractions that have been pre-pared by conventional methods, the remainder comprising one or more foots oils and/or slack waxes derived from lubricating oils that have been obtained by hydrocracking.

7. A process as claimed in claim 1, characterized in that a catalyst is used that contains at least one metal selected from the group formed by nickel and cobalt and at least one metal selected from the group formed by molybdenum and tungsten.

8. A process as claimed in claim 1, 3 or 4, characterized in that the catalyst is used in sulphidic form.

9. A process as claimed in claim 1, 3 or 4, characterized in that the catalyst contains alumina as carrier.

10. A process as claimed in claim 1, characterized in that a fluorine-containing nickel-tungsten catalyst on alumina as carrier is used, which catalyst has a compacted bulk density of at least 0.8 g/ml, contains at least 3 parts by weight of nickel and 20 parts by weight of tungsten, respectively, per 100 parts by weight of carrier and has been prepared as follows from an alumina hydrogel from which a xerogel with a compacted bulk density of less than 0.8 g/ml can be obtained by drying and calcining:
1) if the pore volume quotient of the said xerogel is at least 0.5, the pre-paration of the catalyst takes place either a) by drying and calcining the alumina hydrogel, incorporation of the metals and, if desired, fluorine into the xerogel, and drying and calcining of the composition, or b) by incorporation of the metals and, if desired, fluorine into the alumina hydrogel and drying and calcining the composition;
2) if the pore volume quotient of the said xerogel is less than 0.5, the preparation of the catalyst takes place by incorporation of the metals and at least part of the fluorine into the alumina hydrogel and drying and cal-cining of the composition, provided that in the latter case fluorine is in-corporated into the alumina hydrogel in sufficient quantity that from this fluorine-containing alumina hydrogel a xerogel with a pore volume quotient of at least 0.5 can be obtained by drying and calcining.

11. A process as claimed in claim 1, 3 or 10, characterized in that a fluorine-containing nickel-tungsten catalyst on a carrier is used, into which catalyst at least part of the fluorine has been incorporated by in-situ fluoriding.

12. A process as claimed in claim 1, 3 or 10, characterized in that it is carried out at a temperature of 350°C-425°C, a pressure of 40-200 bar, a space valocity of 0.5-1.5 kg of feed/l of catalyst/hr and a hydrogen/feed ratio of 500-2500 N1 hydrogen/kg of feed.

13. A process as claimed in claim 1, 3 or 10, characterized in that the hydrocracking of the mixture of heavy hydrocarbons is followed by hydrofinish-ing of the hydrocaracked product.

14. A process as claimed in claim 1, 3 or 10, characterized in that the effluent from the hydrocracking reactor or, if hydrofinishing is used, the effluent from the hydrofinishing reactor, is separated by distillation into one or more light fractions and a residual fraction with an initial-boiling point between 350 and 550°C that the residual fraction is dewaxed and that at least part of the separated paraffin wax is recirculated to the hydrocracking reactor.