EP3545054B1

EP3545054B1 - Process for producing an extender process oil

Info

Publication number: EP3545054B1
Application number: EP17804534.0A
Authority: EP
Inventors: Miguel Ángel GARCÍA CARREÑO; Íñigo RIBAS SANGÜESA; Diana Cano Chacon; Ponciano PÉREZ NEBREDA; Gloria MONTEALEGRE GARCÍA
Original assignee: Repsol SA
Current assignee: Repsol SA
Priority date: 2016-11-24
Filing date: 2017-11-23
Publication date: 2021-05-26
Anticipated expiration: 2037-11-23
Also published as: WO2018096042A1; ES2881516T3; EP3545054A1

Description

This application claims the benefit of European Patent Application EP16382554 filed on 24.11.2016 .
The present disclosure is concerned with an improved process for preparing extender process oils.

BACKGROUND ART

Distillate aromatic extracts (DAE) are currently used as aromatic process oils for the manufacture of oil extended natural or synthetic rubber and also tire compounds. Nevertheless, these oils contain high levels of polycyclic aromatic hydrocarbons (PAH) and polycyclic aromatic compounds (PCA). The content on PCA in DAE is found in concentrations very much in excess of 3 %wt determined in accordance with the IP-346 method. Therefore, process oils of the distillate aromatic extract type have consequently been classified as "carcinogenic" according to the European legislation (EU Substance Directive 67/548/EEC). PAHs are organic compounds possessing two or more aromatic rings, of which eight types are identified as carcinogens. These are Benzo[a]pyrene, Benzo[e]pyrene, Benzo[a]anthracene, Benzo[b]fluoranthene, Benzo[j]fluoranthene, Benzo[k]fluoranthene, Dibenzo[a,h]anthracene and Chrysene. Many other PAHs are harmful to health and environment. DAE are obtained as by-products from the solvent-extraction step during the refining of standard lubricating base oils.
Treated Distillate Aromatic Extract (TDAE) is a non-carcinogenic mineral oil, used as aromatic process oils for the manufacture of oil extender natural or synthetic rubber and tire compounds. This environment friendly extender process oil is used as a softening additive in the process of vulcanization of natural rubber and as a component of rubber compounds. Its high viscosity gravity constant (VGC) leads to the reduction in heat buildup and rotational resistance during the usage of tires.
Generally, TDAEs are obtained in a process which comprises atmospheric distillation of crude oil to separate gas, naphta, kerosene and diesel fractions. The atmospheric residue is separated into a vacuum residue and one or more distillates in a vacuum distillation. The distillate is then separated into a raffinate and a extract (primary extract or DAE) in a extraction unit using a polar extraction solvent. Lubricating base oils and waxes are obtained from the raffinate. A second extraction of the primary extract affords the TDAE and a high-PCAs content residue (secondary extract).
The skilled person in the art is seeking for new methods of obtaining TDAE with a better yield and/or an improvement in its technical properties. Thus, in WO0071643 it is disclosed a process of preparation of a process oil having a PCAs content lower than 3 %wt. and an aniline point between 80 °C to 120 °C, the method comprising hydrotreating naphthenic distillates under specific conditions.
US6103808 discloses various processes for producing extender process oil; wherein it is demonstrated that introducing modifications in the processes of preparation, results in important variations in the properties of the product thus obtained.
WO2016183195 discloses different extender process oils characterized by its properties; and a process for the preparation thereof comprising an atmospheric distillation, a vacuum distillation, mixing and hydrotreatment.
CN1060467 discloses a process for the preparation of a process oil, the process comprising a double extraction step followed by a hydrotreatment step.
US20160333279 discloses a process for producing naphthenic process oils by hydrogenation or a process oil educt that has a high content of polycyclic aromatics.
EP839891 discloses a process for obtaining aromatic oils having a po.lycyclic aromatic compounds content of less than 3% (IP-346) from the mixed extract flow obtained in the manufacture of lubricant base oils.
US20010007049 discloses process oil obtained by mixing a primary extract and lubricanting base oil and subjecting the mixture to extraction with a solvent.
From what is known in the art it is derived that there is a need for a process which can produce extender process oils which meet several technical specifications simultaneously. Particularly, having simultaneously the following technical specifications: kinematic viscosity at 100 °C from 16 to 30 cSt determined in accordance with ASTM D-445, an aniline point from 55 to 80 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt. determined in accordance with the IP-346 method, a Tg minimum of -56 °C (preferably between -56°C <Tg< -47°C) determined in accordance with DSC, and an aromatic content higher or equal to 24 %wt. determined in accordance with ASTM D-2140; the process oil being obtained in a high yield independently of the properties of the crude feedstock.

SUMMARY

Inventors have found a method for producing an extender process oil which meets various technical specifications simultaneously. Particularly, the inventors have found a method for producing an extender process oil having a kinematic viscosity at 100 °C from 16 to 30 cSt determined in accordance with ASTM D-445, an aniline point from 55 to 80 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt. determined in accordance with the IP-346 method, a Tg minimum of -56 °C (preferably between -56°C <Tg< -47°C) determined in accordance with Differential Scanning Calorimetry (DSC), and an aromatic content higher or equal to 24 %wt. determined in accordance with ASTM D-2140.
Preferably, Tg value is comprised between -56°C <Tg< -47°C, more preferably between -55°C <Tg< -49°C; particularly preferred between -54°C <Tg< -50°C. Alternatively, preferably Tg values are comprised between -53.5°C <Tg< -50.5°C; more preferably between -53°C <Tg< -51°C.
In the context of the present invention, the term "gap" refers to the difference between the 5% of the heavy cut and the 95% of the light cut, the temperatures measured according to ASTM D-2887, being heavy and light cuts contiguous cuts.
In a vacuum distillation, the heavy cut is the cut with higher TBP (true boiling point) and the light cut is the one with lower TBP being both contiguous cuts. The term "anti-solvent" refers to a solvent that is mixed with the main one in order to change the mixture polarity and so, its selectivity and extraction power.
The term "counter-solvent" refers to a solvent that is mixed with the feed and present an opposite polarity from the main solvent. Its use changes the extraction equilibrium and so, the process selectivity. In this process, the counter-solvent is a not polar component.
Briefly, in accordance with a first aspect of the present disclosure, it is provided a method for producing an extender process oil according to claim
The extender process oil obtainable by the process meets simultaneously all the following technical specifications: a kinematic viscosity at 100 °C from 16 to 30 cSt determined in accordance with ASTM D-445, an aniline point from 55 to 80 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt determined in accordance with IP-346 method, a Tg comprised between -56°C <Tg< -47°C determined in accordance with DSC, and an aromatic content higher or equal to 24 %wt determined in accordance with ASTM D-2140.
Preferably, the extended process oil obtainable by the process of the invention, shows a Tg value between -55°C <Tg< -49°C; more preferably between -54°C <Tg< -50°C; being particularly preferably Tg values comprised between -53.5°C <Tg< -50.5°C; and even more preferably between -53°C <Tg< -51°C.
In addition, a use is disclosed of a extender process oil that is obtainable by the process of the present disclosure as a plasticizer or extender oil for rubbers or rubber mixtures that are based on natural and synthetic rubbers, or for thermoplastic elastomers, as a raw material for technical or medicinal white oils, as printing ink oils, as a release agent for architectural coatings, or industrial fat production, transformer oils, or special metalworking oils.
Additionally, according to yet a further example of the present disclosure there is provided the use of the extender process oil that is obtainable by the process of the present disclosure in pneumatic tyres production. According to yet an additional example of the present disclosure there is provided a pneumatic tyre comprising a rubber composition, wherein the rubber composition comprises the extender process oil as described herein.
It is known in the art the difficulty of obtaining an extender process oil which meets simultaneously various of the above mentioned technical specifications. Difficulty which increases when the feedstock properties are not the appropiates.
Thus, the process of the present disclosure, produces an extender process oil which meets simultaneously all the technical features above mentioned, independently of the properties of the feedstock used. Flexibility of the new process regarding fluctuation of feedstock quality is higher than current state of the art. Furthermore, the extender process oil may be obtained at yields up to 80 %wt versus up to 50 %wt yield which may be obtained in the conventional process for obtaining extender process oils.

DETAILED DESCRIPTION

For purposes of the present invention, any ranges given include both the lower and the upper end-points of the range. Ranges given, such as temperatures, times, and the like, should be considered approximate, unless specifically stated.
The viscosity indicates the ability of an oil to flow. If viscosity is high, molecular weight is generally high and compatibility with the rubber is less, so more mixing time is required for the full dispersion of additives. The high viscosity oil needs to be heated to reduce its viscosity before being added to the rubber compound. There are two different types of viscosity; i.e. dynamic and kinematic viscosities. Dynamic viscosity is a measure of a liquid's resistance to movement and is measured in centipoise (cP). Kinematic viscosity is a measure of the velocity of a liquid and is obtained by measuring the time taken for a certain quantity of liquid to pass through a capillary tube. It is measured in centistokes, where 1 cSt = 1 mm²/sec. Kinematic viscosity is determined in accordance with ASTM D-445.
The aniline point is measured according to ASTM D-611 and is based on a measurement of the temperature at w hich aniline dissolves in the oil. The aniline point is a measure of the solvency of the oil. Low aniline points indicate a high solvency of the oil, and also high aromaticity.
There are a number of methods to measure the polycyclic aromatic content of the oil; e.g. IP-346 (an analytical method essentially measuring the level of certain polyaromatic compounds through selective extraction with a solvent). The IP-346 method is used for deciding which oils have to be labelled under European Community (EU) legislation. It measures the content of substances that are soluble in dimethyl Sulfoxide (DMSO). DMSO dissolves all polyaromatics and a number of single aromatics and naphthenes, especially if they contain a heteroatom. Oils with a value of 3 %wt (by weight) and above have to be labelled in Europe. The aromatic oils must be labelled with the risk phrase "R45" (may cause cancer) and the label "T" (toxic, skull and crossbones) in Europe.
Carbon-type analysis provides a means of distinguishing these materials by utilizing the correlations obtained between the physical properties of pure compounds and hydrocarbon oils containing many types of molecules. ASTM D-2140 method calculates the weight percentage of carbon atoms involved in each type of bond - aromatic, naphthenic and paraffinic - from the viscosity constant, refractive index and density.
In accordance with an embodiment of the present disclosure, optionally in combination with one or more features of the particular embodiments defined herein, the order of steps c) and d) may be modified, thus the hydrotreated oil obtained in step b) is extracted first and vacuum fractionated later.
Referring to the Figure 1, a feedstock comprising a process oil educt (VI) having a PCAs concentration from 3 % wt to 55 % wt, preferably from 5-52% wt, more preferably from 10-35 % wt; particularly preferred from 13-25 % wt; and a kinematic viscosity from 16 to 250 cSt, preferably from 17 to 200 cSt; is fed via line 1 to a hydrotreating unit A where it is treated in a single hydrotreating stage. Hydrotreating stage is operated within a temperature from 300 to 380 °C, a pressure from 40 to 200 bar and a liquid space velocity from 0.1 to 1.5 h^-1, to provide a hydrotreated oil. After hydrotreating, the hydrotreated oil is fed via line 2 to a vacuum fractionation tower B, obtaining a heavier fraction where the 5% according to ASTM D-2887 is at a temperature from 400 to 465 °C and a gap value equal or higher than -35 °C, preferably equal or higher than -30 °C, more preferably equal or higher than -27 °C; being the gap defined as the difference between the 5% of the heavier fraction and the 95% of lights, the temperatures measured according to ASTM D-2887. One of the objectives of this step is to have in the heavy product a kinematic viscosity at 100 °C from 16-60 cSt. Vacuum fractionated hydrotreated oil thus obtained is fed via line 3 to an extraction unit C, and at least a polar extraction solvent or a mixture of solvents (being at least one of them a polar solvent) is fed via line 4 to the extraction unit C. A liquid-liquid extraction process is thus performed under conditions sufficient to provide an extract (VII) and an extender process oil (VIII), the extender process oil (VIII) having a viscosity at 100 °C from 16 to 30 cst determined in accordance with ASTM D-445, an aniline point from 55 to 80 determined in accordance with ASTM D-611, a content of polycyclic aromatics (PCA) of less than 3 % w determined in accordance with IP-346 method, a Tg minimum of -56 °C (preferably between -56°C <Tg< -47°C) determined in accordance with DSC, and an aromatic content higher or equal to 24%w determined in accordance with ASTM D-2140.
Therefore, referring to Figure 2, a primary extract (II) (Distillate Aromatic Extract) obtainable by solvent extraction of vacuum distillates (III) in the lubricating base oil (I) preparation, is fed via line 10 to an extraction unit D, wherein at least a polar extraction solvent is fed via line 11 to the extraction unit D to produce a Treated Distillate Aromatic Extract (IV) and a secondary extract (V). Thus, the secondary extract is obtainable by solvent extraction of a primary extract with a solvent or a mixture of solvents, where at least one solvent is a polar extraction solvent. Process oil educt (VI) which is fed via line 1 to the hydrotreating unit A, may comprise at least one of the secondary extract or the primary extract.
In accordance with a particular embodiment of the present disclosure, extraction unit D may be the same as extraction unit C. In this particular embodiment, primary extract (II) is fed via line 7 to an extraction unit C, and extract obtained (VII) is fed to the hydrotreating unit A via line 8.
As mentioned above, primaray extract (II) is obtainable by solvent extraction of vacuum distillates (III) in the lubricating base oil (I) preparation; vacuum distillates (III) are obtainable by vacuum distillation in a vacuum distillation unit F of the atmospheric residue resulting of the atmospheric distillation of crude oil (X) in an atmospheric distillation unit G.
In accordance with an embodiment of the present disclosure, the process oil educt which is used as feed to the hydrotreating unit A comprises a mixture of a secondary extract and a primary extract in a ratio from 25 %wt to 75 %wt up to 75 %wt to 25 %wt. Preferably, the process oil educt comprises a mixture of a secondary extract and a primary extract in a ratio from 40 %wt to 60 %wt up to 85 %wt to 15 %wt; more preferably, 50 %wt to 50 %wt up to 95 %wt to 5 %wt. In another particular embodiment, the process oil educt comprises at least 95 %wt of secondary extract; more preferably the process oil educt comprises at least 99 %wt of secondary extract.
The extract (VII) obtained in step d), may be recirculated to the hydrotreatment step b) to maximize the yield of TDAE. Therefore, referring to Figure 2, at least a portion of extract (VII) obtained in step d) may be recirculated via line 8 and combined with the process oil educt (VI) which is fed via line 1 to the hydrotreating unit A.
Thus, in accordance with an embodiment, optionally in combination with one or more features of the particular embodiments defined herein, the extract (VII) obtained in step d), is recirculated to the hydrotreatment step b).
In accordance with a particular embodiment of the present disclosure, at least a portion of a primary extract (II) obtainable by solvent extraction of vacuum distillates (III) in the lubricating base oil (I) preparation, may be mixed with the vacuum fractionated hydrotreated oil stream obtained in step c) previously to the liquid-liquid extraction step d). Thus, referring to Figure 2, at least a portion of a primary extract (II) is passed through line 7 and combined with the vacuum fractionated hydrotreated oil stream obtained in the vacuum distillation unit B, and the mixture is fed via line 3 to the extraction unit C.
In accordance with an embodiment of the present disclosure, optionally in combination with one ore more features of the particular embodiments defined herein, the hydrotreating step is carried out at temperatures from 320 to 370 °C, preferably from 330 to 360 °C. Regarding to the pressure of the hydrotreating step, it is preferably from 40 to 200 bar, preferably from 40 to 160 bar; more preferably from 45 to 75 bar, being particularly preferred from 50 to 70 bar. This pressure refers to the total pressure at the reactor exit. The hydrotreatment step is preferably carried out at a liquid space velocity from 0.1 to 1.5 h^-1, preferably from 0.2 to 1.2 h^-1, more preferably from 0.25 to 0.8 h^-1, yet more preferably from 0.35 to 0.75 h^-1.
In accordance with a particular embodiment, optionally in combination with one ore more features of the particular embodiments defined herein, the hydrotreating step is carried out at temperatures from 320 to 370 °C, a pressure from 45 to 75 bar, and a space velocity from 0.25-0.8 h^-1. In a another particular embodiment, hydrotreating step is carried out at temperatures comprised of from 330 to 360 °C; pressure comprised of from 50 to 70 bar; and space velocity comprised of from 0.35 to 0.75 h^-1.
After hydrotreating, hydrogen sulfide and ammonia formed during the hydrotreating may be removed by any known method. For example, the hydrotreated material may be passed to a stripping vessel and an inert stream may be used to strip the hydrogen sulfide and ammonia from the hydrotreated material by using techniques well-known in the art.
In an embodiment, optionally in combination with one or more features of the particular embodiments defined herein, the vacuum fractionating step c) is carried out in a vacuum fractionation tower obtaining a heavier fraction where the 5% according to ASTM D-2887 is at a temperature from 400 to 465 °C, preferably from 410 to 455 °C, more preferably from 413 to 445 °C; the gap value being equal or higher than -35 °C, preferably equal or higher than -30 °C, more preferably equal or higher than -27 °C; being the gap defined as the difference between the 5% of the heavier fraction and the 95% of lights, the temperatures measured according to ASTM D-2887.
The kinematic viscosity at 100 °C of the vacuum fractionated hydrotreated oil stream thus obtained is from 16 to 60 cSt, preferably from 17 to 50 cSt.
The skilled person knows that it may be possible to achieve the same separation with different combinations of the column design variables, as for example number of equilibrium stages, reflux ratio, internal column devices design, pressure, etc.
In an embodiment, optionally in combination with one or more features of the particular embodiments defined herein, the polar solvent of the liquid-liquid extraction step d) is selected from furfural, N-methylpyrrolidone, dimethylsulfoxide, N-N-dimethylformamide, methylcarbonate, morpholine, and the like. Particularly preferred is furfural. The extraction may be conducted in a counter current type extraction unit.
In the process of the present disclosure, an anti-solvent may optionally be added to the flow of the extraction solvent. An example of anti-solvent is water. The presence of an anti-solvent allows to increase selectivity.
In accordance with another embodiment, a counter-solvent may be added to increase the extraction performance. Example of counter-solvents suitable for the process are hydrocarbons with a boiling point of less than 160 °C, preferably less than 140 °C. Particularly preferred examples of counter-solvent are C6 and n-heptane.
In accordance with an embodiment, optionally in combination with one or more features of the particular embodiments defined herein, the vacuum fractionated hydrotreated oil stream obtained in step c) is extracted with an extraction solvent; the ratio of extraction solvent to extraction unit feed stream is from 0.5 to 4.5, preferably from 0.7 to 4.0, more preferably from 0.9 to 3.7, being particularly preferred from 1.0 to 3.5.
The hydrotreating catalyst used in hydrotreating step is important but not critical. It may be used different hydrogenation commercial catalysts , and the skilled person may choose among a huge variety of catalysts. In accordance with an ambodiment, optionally in combination with one or more features of the particular embodiments defined herein, the hydrotreatment step b) is carried out in presence of a hydrotreating catalyst based on a metal sulfide catalyst where metal could be nickel, cobalt, molibdenum, chromium, vanadium, tungsten, phophorous, nickel-cobalt, nickel-cobalt-molybdenum, nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, chromium-vanadium catalyst, or a mixture thereof. Particularly preferred are nickel-molybdenum sulfide catalysts promoted or not with phosphorous.
In a particular embodiment, optionally in combination with one or more features of the particular embodiments defined herein, the process comprises

a) providing a process oil educt that has a content of polycyclic aromatics from 3% w/w to 55 % w/w, determined in accordance with IP346, and a kinematic viscosity at 100°C from 16 to 250 cSt determined in accordance with ASTM D-445; the process oil educt comprises at least one of a primary extract or a secondary extract
- a.1) wherein the primary extract is obtainable by solvent extraction of vacuum distillates in the lubricating base oil preparation; and
- a.2) wherein the secondary extract is obtainable by solvent extraction of the primary extract as obtained in a.1) with a solvent or a mixture of solvents, where at least one solvent is a polar extraction solvent;
b) hydrotreating the process oil educt ; wherein the hydrotreatment is carried out at a temperature from 320 to 370 °C, a pressure from 45-75 bar, and a space velocity from 0.25-0.8 h^-1; to provide a hydrotreated oil;
c) vacuum fractionating the hydrotreated oil obtained in step b) in a vacuum tower obtaining a heavier fraction where the 5% according to ASTM D-2887 is at a temperature from 410 to 455 °C, and a gap equal or higher than -35 °C to provide a vacuum fractionated hydrotreated oil having a kinematic viscosity from 16-60 cSt; and
d) contacting the vacuum fractionated hydrotreated oil obtained in step c) with furfural in an extraction unit and performing a liquid-liquid extraction process, obtaining an extender process oil having a viscosity at 100 °C from 16 to 30 cSt determined in accordance with ASTM D-445, an aniline point from 55 to 80 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt determined in accordance with IP-346 method, a Tg minimum of -56 °C (preferably between -56°C <Tg< -47°C), and an aromatic content higher or equal to 24 %wt determined in accordance with ASTM D-2140.

In accordance with a particular example, the extender process oil obtainable by the process of the present disclosure has a viscosity at 100 °C from 16 to 24 cSt determined in accordance with ASTM D-445, an aniline point from 65 to 75 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt determined in accordance with IP-346 method, a Tg minimum of -53 °C determined in accordance with DSC, and an aromatic content higher or equal to 26 %wt determined in accordance with ASTM D-2140.
In accordance with another example, the extender process oil obtainable by the process of the present disclosure has a viscosity at 100 °C from 16 to 24 cSt determined in accordance with ASTM D-445, an aniline point from 65 to 75 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt determined in accordance with IP-346 method, a Tg value comprised between -54 °C<Tg< -50°C determined in accordance with DSC, and an aromatic content higher or equal to 26 %wt determined in accordance with ASTM D-2140.
Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and/or equivalents thereof are possible.
Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow.
Throughout the description and claims the word "comprise" and variations of the word, are not intended to exclude other technical features, additives, components, or steps. Furthermore, the word "comprise" encompasses the case of "consisting of". Additional objects, advantages and features of the invention will become apparent to those skilled in the art upon examination of the description or may be learned by practice of the invention. The following examples are provided by way of illustration, and they are not intended to be limiting of the present invention. Furthermore, the present invention covers all possible combinations of particular and preferred embodiments described herein.

EXAMPLES

In the following examples, two different hydrocarbon streams having high PCA's content and different properties were used.

		Feedstock 1	Feedstock 2
Density 15°C (g/ml)	ASTM D-1250	1.0324	0.9993
Refractive Index (IR) 60°C	ASTM D-1747	1.5747	1.5500
Viscosity 65°C (cSt)	ASTM D-445	321.0	179.4
Viscosity 100°C (cSt)	ASTM D-445	42.10	30.13
Pour Point(°C)	ASTM D-97	9	24
Aniline point(°C)	ASTM D-611	27	-
Carbon distribution	ASTM D-2140	With S	With S
C. Aromatics (%w)		42.7	35.0
C. Naphthenics (%w)		11.9	11.7
C. Paraffinics (%w)		45.4	53.2
Sulphur (%w)	ASTM D-4294	5.016	4.330
PCA's (%w)	IP-346	20.5	15.5
Aromatics	HPLC
Monoaromatics (% w)		17.22	28.22
Diaromatics (% w)		16.5	8.13
Polyaromatics (tri+) (% w)		33.02	26.92
Di+aromatics (% w)		49.52	35.06
Total Aromatics (% w)		66.74	63.28
Simulated Distillation, ASTM D-2887, °C
	1%	359.2	350.8
	5%	415	420.4
	10%	438.7	444.5
	30%	472.4	475.6
	50%	490.3	493
	70%	508.4	510.8
	90%	535.6	536.5
	95%	548.7	548.5
	PF	591.6	582.8

Feedstocks 1 and 2 were treated in accordance with the method of the present disclosure in order to obtain a TDAE which meet the technical specifications and with a high yield.

Example 1

Feedstock 1 was passed through a hydrotreating stage under the conditions outlined below:

Pressure 55 bar
Hydrogen:feed ratio (THC) 550 Nl/l
LHSV 0.37 h^-1
Temperature 360 °C

Hydrotreatment was carried out using a commercial NiMo hydrogenation catalyst having a Ni content of 3.6 %wt and a Mo content of 15.6 %wt supported on Alumina. Technical characteristics of the catalyst are as follows:

	Catalyst NiMo
Form	TRILOBE
Diameter, mm	1.14
Dist.length
<2,0mm, %	26.6
<2,5mm, %	54.2
<3,0mm, %	74
<4,0mm, %	91.9
Average length, mm	2.61
10 % < a: en mm	1.63
50 % < a: en mm	2.42
90 % < a: en mm	3.82
Maximum value, mm	8

Elemental analysis
C, %	3.82
H, %	1.47
N, %	0.1
S, %	0.1

ICP metals of Hydrotreating Catalyst
Ni, %	3.59
deviation +/-%	0.03
Mo, %	15.61
deviation +/-%	0.1

Mechanical properties
Shell Index (bcs), MPa	1.51
Burst pressure axial, Kp	2.4
Burst pressure radial, Kp
Ignition loss 480°C/1 h, %w	13.21

Textural properties
Specific Surface area BET, m²/g	137
Pore volumen by Hg, cm³/g	0.33
Average pore diameter (A)	96
Pore volumen by N₂, cm³/g	0.35
Average pore diameter (A)	89

Physical properties
Density TAP, g/cm³	1.11
Apparent density, g/cm³	0.99

Catalyst was sulphided according a conventional sulphiding protocol.
Sulphiding protocol include following stages:

a) Drying step, where catalyst was exposed to a hydrogen on nitrogen stream, and temperature was increased till 150°C.
b) Wetting step, where Straight run gasoil was fed to reactor. Hidrogen was also feed. The hydrocarbon stream was also spiked with DMDS at 2% w/w.
c) Sulphiding step. Temperature was increased from 150°C till 230°C at 10°C/hour. At 230°C temperature was kept during 12 hours. Then temperature was increased to 350 °C at 10°C/hour.
d) Stabilization step. Finally hidrocarbon stream was kept at 350°C during three days to get a proper sulphiding and stabilization. In that moment, start up was finished and normal feed was introduced.

Hydrogenated product was vacuum fractionated in a column with 15 theoretical stages, wherein the heavier fraction has a 5% according to ASTM D-2887 of 413 °C.
Fractionated weight product (413 °C for the 5% meassure acording to ASTM D-2887) showed following properties:
Density 15 °C: 0.9803 kg/l
S content: 1.133 % wt.
Viscosity 100°C: 24,5 cst
IR at 70°C: 1.5366
Simulated distillation - ASTM 2887, °C

1% 301.8

5%, 413.5

6%, 417.3

7%, 420.5

8%, 423.2

9%, 425.7

10%, 427.9

30%, 456.3

50%, 475.9

70%, 494.9

90%, 522.3

95%, 535.3

99%, 559.4

Yield 70 % weight
Fractionated weight product (413 °C for the 5% meassure acording to ASTM D-2887) was sent to the extraction unit wherein an extraction with furfural was carried out under following conditions (Pilot Plant):

Temperature: 60 °C (top column) y 45 °C (bottom column)
Furfural/Feed ratio: 2
The yield obtained in TDAE was 51 %wt

The product properties were:

Density 15°C (g/ml)	ASTM D-1250	0.9433
Density 70°C (g/ml)	ASTM D-4052	0.9064
Relative Density 15.6°C	ASTM D-1250	0.9436
Refractive Index20°C	extrapolated	1.5263
Refractive Index 60°C	ASTM D-1747	1.5103
Viscosity 40°C (cSt)	ASTM D-341	324.6
Viscosity 70°C (cSt)	ASTM D-445	55.75
Viscosity 100°C (cSt)	ASTM D-445	17.6
Pour point (°C)	ASTM D-97	30
Aniline point (°C)	ASTM D-611	71
Carbon distribution	ASTM D-2140
C. Aromatics (%)	(without S)	26
C. Naphthenics (%)		25.9
C. Paraffinics (%)		48.1
Tg (°C)	ITLAB-103 Apto. C	-52.1
PCA's (%w)	IP-346	2.8

Example 2

Feedstock 2 was passed through a hydrotreating stage under the conditions outlined below:

Hydrotreatment was carried out using the same catalyst of Example 1 which was sulphided according protocol explained in Example 1.

Hydrogenated oil thus obtained showed the following properties:

Density 15 °C (g/cm3)	0.9747
S, (% w)	0.8465
N (ppm)	1082
Viscosity @ 65°C (cSt)	45.41
Viscosity @ 100°C (cSt)	12.33
Aniline Point (°C)	59.5
Pour Point (°C)	27
Microcarbon residue	0.33

AROMATICS UV RR921
Monoaromatics (% w)	52.93
Diaromatics (% w)	15.4
Triaromatics (% w)	12.56
Polyaromatics (% w)	27.96
Molecular Weight	390

Hydrogenated product was vacuum fractionated in a column with 15 theoretical stages, wherein the heavier fraction has a 5% according to ASTM D-2887 of 413 °C.

Fractionated weight product (413 °C for the 5% meassure acording to ASTM D-2887) showed following properties:

Viscosity 40°C (cst)	459
Viscosity 65°C (cst)	89.82
Viscosity 100°C (cst)	20.02
S (% w)	0.9470
Density a 15°C (g/cc)	0.9573
ASTM D2887, °C
IBP	424
1%	427
5%	437.3
10%	444.9
30%	466.7
50%	483.8
70%	501.3
90%	527.1
95%	539.1
99%	560.6
FBP	568.6

Yield obtained in heavy fraction was 75.7 % wt. Fractionated weight product (413 °C for the 5% meassure acording to ASTM D-2887) was sent to the extraction unit wherein an extraction with furfural was carried out under the following conditions (laboratory test):

Temperature: 50°C
Ratio Furfural/HC: 2,8
TDAE yield 73.7%weight

TDAE thus obtained showed the following properties:

SAM PLE		TDAE
SAM PLE		413 °C (F/C=2.8)
		350°C; 55bar
Density 15°C (g/ml)	ASTM D-1250	0.9378
Density 70°C (g/ml)	ASTM D-4052	0.9009
Relative Density 15,6°C	ASTM D-1250	0.938
Refraction Index 20°C	extrapolated	1.5227
Refraction index 60°C	ASTM D-1747	1.5067
Viscosity 40°C (cSt)	ASTM D-341	326.4
Viscosity 70°C (cSt)	ASTM D-445	52.42
Viscosity 100°C (cSt)	ASTM D-445	16.82
Pour Point (°C)	ASTM D-97	----
Aniline Point (°C)	ASTM D-611	74.95
Carbon distribution	ASTM D-2140
C. Aromatics (%)	(without S)	24.0
C. Naftenics (%)		25.2
C. Parafinics (%)		50.8
VGC		0.8735
S (%w)	ASTM D-5453	----
Tg (°C)	ITLAB-103	-54.6
PCA's (%w)	IP-346	2.65

Example 3.

Hydrotreatment was carried out using the NiMo hydrogenation catalyst of Example 1, which was sulphided according protocol explained in Example 1. Hydrogenated oil thus obtained showed the following properties:

Density 15 °C (g/cm3)	0.9747
S (w%)	0.8465
N (ppm)	1082
Viscosity @ 65°C (cSt)	45.41
Viscosity @ 100°C (cSt)	12.33
Aniline Point (°C)	59.5
Pour Point (°C)	27
Microcarbon Residue	0.33

Hydrogenated product was vacuum fractionated in a column with 1 theoretical stage, obtaining two fractions with different distillation curves wherein the heavier fraction has a 5% according to ASTM D-2887 of 461 °C.

Fractionated weight product (461°C for the 5% meassure acording to ASTM D-2887) showed following properties:

Viscosity 65°C (cst)	114.4
Viscosity 100°C (cst)	23.72
S, %wt	1.038
Density a 15°C (g/cc)	0,9604
Aniline Point (°C)	67.9
ASTM D2887, °C
IBP	444.8
1%	450.1
5%	461.1
10%	467.3
30%	482.9
50%	496.5
70%	511.7
90%	536
95%	548
99%	578

Yield obtained in heavy fraction was 60 % wt. Fractionated weight product (461°C for the 5% meassure acording to ASTM D-2887) was sent to the extraction unit wherein an extraction with furfural was carried out under following conditions (laboratory test):

Temperature: 50°C
Ratio Furfural/HC: 3.5

TDAE yield was 69,6% wt and TDAE thus obtained showed the following properties:

SAM PLE		TDAE
SAM PLE		461 °C (F/C=3.5)
		350°C; 55bar
Density 15°C (g/ml)	ASTM D-1250	0.9379
Density 70°C (g/ml)	ASTM D-4052	0.901
Relative Density	ASTM D-1250	0.9381
Refraction Index	extrapolated	1.5224
Refraction index	ASTM D-1747	1.5064
Viscosity 40°C (cSt)	ASTM D-341	334.7
Viscosity 70°C (cSt)	ASTM D-445	58.81
Viscosity 100°C (cSt)	ASTM D-445	18.5
Pour Point (°C)	ASTM D-97	-
Aniline Point (°C)	ASTM D-611	78.85
Carbon distribution	ASTM D-2140
C. Aromatics (%)	(without S)	24
C. Naftenics (%)		26
C. Parafinics (%)		50
VGC		0.8734

Tg (°C)	ITLAB-103 Apto. B
Tg (°C)	ITLAB-103 Apto. C	-52.02
PCA's (%w)	IP-346	2

Example 4.

Pressure 55 bar
Hydrogen:feed ratio (THC) 550 Nl/l
LHSV 0.74 h^-1
Temperature 350 °C

Hydrotreatment was carried out using the NiMo hydrogenation catalyst of Example 1, which was sulphided according protocol explained in Example 1.

Hydrogenated oil thus obtained showed the following properties:

Density 15 °C (g/cm3)	0.9841
S (%)	1.4160
N (ppm)	1403
Viscosity @ 65°C (cSt)	60.56
Viscosity @ 100°C (cSt)	14.94
Aniline Point (°C)	56.4
Pour Point (°C)	27
Microcarbon residue	0.54
AROMATICS UV RR921
Monoaromatics (% w)	52.29
Diaromatics (% w)	16.75
Triaromatics (% w)	15.96
Polyaromatics (% w)	32.71
Molecular Weight	390
Simulated distillation - ASTM D-2887, °C
	176.1
	312.8
	374.4
	437.5
	465.6
	487.7
	517
	530.1
	552
	558.8

Viscosity 65°C (cst)	91.53
Viscosity 100°C (cst)	19.7
S, (% w)	1.46
Density 15°C (g/cc)	0.962
Aniline Point (°C)	58
Simulated Distillation ASTM D-2887, °C
IBP	392
1%	398.3
5%	417.7
10%	430.8
30%	462
50%	482.1
70%	500.9
90%	527.7
95%	539.9
FBP	568.7

Yield obtained in heavy fraction was 91.95 % wt. Fractionated weight product (413 °C for the 5% meassure acording to ASTM D-2887) was sent to the extraction unit wherein an extraction with furfural was carried out under following conditions (laboratory test)

Temperature: 50°C
Ratio Furfural/HC: 4
TDAE yield 60,5%

TDAE thus obtained showed the following properties:

SAM PLE		TDAE Phase	2
SAM PLE		413 °C (F/C=4)
Density 15°C (g/ml)	ASTM D-1250	0.9343
Density 70°C (g/ml)	ASTM D-4052	0.8974
Relative Density 15.6°C	ASTM D-1250	0.9345
Refraction Index 20°C	extrapolated	1.5224
Refraction index 60°C	ASTM D-1747	1.5064
Viscosity 40°C (cSt)	ASTM D-341	243.6
Viscosity 70°C (cSt)	ASTM D-445	46.48
Viscosity 100°C (cSt)	ASTM D-445	16.08
Pour Point (°C)	ASTM D-97	----
Aniline Point (°C)	ASTM D-611	74.35
Carbon distribution	ASTM D-2140
C. Aromatics (%)	(sin S)	25.2
C. Naftenics (%)		23.1
C. Parafinics (%)		51.7
VGC		0.8735
Tg (°C)	ITLAB-103 Apto.
Tg (°C)	ITLAB-103 Apto.	-55.42
PCA's (%w)	IP-346	2.4

Example 5

In the following example, another different hydrocarbon stream was used.

		Feedstock 3
Density 15°C (g/ml)	ASTM D-1250	1.0134
Refractive Index (IR) 60°C	ASTM D-1747	1.5614
Viscosity 70°C (cSt)	ASTM D-445	88.33
Viscosity 100°C (cSt)	ASTM D-445	22.50
Pour Point(°C)	ASTM D-97
Aniline point(°C)	ASTM D-611	37.6
Carbon distribution	ASTM D-2140	Without S
C. Aromatics (%w)		45.1
C. Naphthenics (%w)		29.6
C. Paraffinics (%w)		25.3
Sulphur (%w)	ASTM D-4294	4.5
Nitrogen (wppm)	ASTM D-4629	2206
PCA's (%w)	IP-346	20.5
Aromatics UV SMS -2783-95
Monoaromatics (%w)		6.12
Diaromatics (%w)		5.56
Triaromatics (%w)		9.17
Tetraaromatics(%w)		8.03
Pentaaromatics(%w)		0.76
Hexaaromatics(%w)		0.93
Hepta+aromatics(%w)		0.43
Pyrenes (%w)		0.67

Simulated Distillation, ASTM D-2887, °C
	1%	386
	5%	403
	10%	412
	30%	440
	50%	472
	70%	493
	90%	521
	95%	533
	PF	558

Feedstock 3 was treated in accordance with the method of the present disclosure in order to obtain a TDAE which meet the technical specifications and with a high yield.
Feedstock 3 was passed through a hydrotreating stage under the conditions outlined below:

Pressure 150 bar
Hydrogen:feed ratio (THC) 950 Nl/l
LHSV 0.78 h-1
Temperature 360 °C

Hydrotreatment was carried out using a conventional and comercial NiMo hydrogenation catalyst supported on Alumina.

Hydrogenated oil thus obtained showed the following properties:

Density 15°C (g/ml)	ASTM D-1250	0.9349
Sulphur (%w)	ASTM D-4294	1.15
Nitrogen (wppm)	ASTM D-4629	1374
Viscosity 70°C (cSt)	ASTM D-445	14.98
Viscosity 100°C (cSt)	ASTM D-445	6.42
Refractive Index (IR) 60°C	ASTM D-1747	1.5082
Aniline Point (°C)	ASTM D-611	61.75
PCAs (%w)	IP-346	6.37
Carbon distribution	ASTM D-2140	Without S
C. Aromatics (%w)		28.45
C. Naphthenics (%w)		25.55
C. Paraffinics (%w)		46
Aromatics UV RR921
Monoaromatics (%w)		24.0
Diaromatics (%w)		92.5
Triaromatics (%w)		11.4
Tetra+aromatics(%w)		65.0

Simulated Distillation, ASTM D-2887, °C
	1%	216
	5%	323
	10%	358
	30%	406
	50%	423
	70%	441
	90%	487
	95%	505
	PF	543

Hydrogenated product was vacuum fractionated in a column with 15 theoretical stages, wherein the heavier fraction has a 5% according to ASTM D-2887 of 436 °C.

Fractionated weight product (436 °C for the 5% volume according to ASTM D-2887) showed the following properties:

Density 15°C (g/ml)	ASTM D-1250	0.9902
Sulphur (%w)	ASTM D-4294	1.86
Viscosity 70°C (cSt)	ASTM D-445	128.2
Viscosity 100°C (cSt)	ASTM D-445	29.5
Aniline Point (°C)	ASTM D-611	44.8
PCA's (%w)	IP-346	12.4

Simulated Distillation, ASTM D-2887, °C
	1%	426
	5%	436
	10%	442
	30%	464
	50%	481
	70%	498
	90%	526
	95%	541
	PF	534

The yield obtained was 27.8 %w related to the feed.
Fractionated weight product (436°C for the 5% volume according to ASTM D-2887) was extracted in a two stages with furfural under the following conditions (laboratory test):

1st stage:
- Temperature: 50 °C
- Ratio Furfural/HC: 3,3
2nd stage:
- Temperature: 50 °C
- Ratio Furfural/HC: 1

TDAE yield : 51.6%wt related to the fractionated weight product.

TDAE thus obtained showed the following properties:

Density 15°C (g/ml)	ASTM D-1250	0.9502
Refractive Index (IR) 60°C	ASTM D-1747	1.5154
Refractive Index (IR) 20°C	Calculated	1.5314
Viscosity 70°C (cSt)	ASTM D-445	56.7
Viscosity 100°C (cSt)	ASTM D-445	17.6
Aniline point(°C)	ASTM D-611	68.2
Carbon distribution	ASTM D-2140	Without S
C. Aromatics (%w)		28.1
C. Naphthenics (%w)		26.2

C. Paraffinics (%w)		45.7
Sulphur (%w)	ASTM D-4294	1.37
PCA's (%w)	IP-346	2.95
Tg (°C)	ITLAB-103	-52.5

Example 6.

In the following example, Feedstock 3 was treated in accordance with the method of the present disclosure in order to obtain a TDAE which meet the technical specifications and with a high yield.
Feedstock 3 was passed through a hydrotreating stage under the conditions outlined below:

Hydrogenated oil thus obtained showed the following properties:

The yield obtained was 27.8 %w related to the feed.
Fractionated weight product (436°C for the 5% volume according to ASTM D-2887) was extracted in the laboratory. In this case, the extraction process was carried out in 4 stages and a counter-solvent (nexane) has been used a part from the polar solvent (furfural). The conditions of the extraction process are:

1st stage:
- Temperature: 50 °C
- Ratio Hexane/HC= 1
- Ratio Furfural/Mixture= 1
2nd stage:
- Temperature: 50 °C
- Ratio Hexane/HC= 1
- Ratio Furfural/Mixture= 1
3rd stage:
- Temperature: 50 °C
- Ratio Hexane/HC= 1
- Ratio Furfural/Mixture= 0.6
4rd stage:
- Temperature: 50 °C
- Ratio Hexane/HC= 1
- Ratio Furfural/Mixture= 0.6

TDAE yield : 43 %wt related to the fractionated weight product. TDAE thus obtained showed the following properties:

Density 15°C (g/ml)	ASTM D-1250	0.9507
Refractive Index (IR) 60°C	ASTM D-1747	1.5159
Refractive Index (IR) 20°C	Calculated	1.5319
Viscosity 70°C (cSt)	ASTM D-445	59.93
Viscosity 100°C (cSt)	ASTM D-445	18.38
Aniline point(°C)	ASTM D-611	67.05
Carbon distribution	ASTM D-2140	Without S
C. Aromatics (%w)		28.4
C. Naphthenics (%w)		25.8
C. Paraffinics (%w)		45.8
PCA's (%w)	IP-346	2.68
Tg (°C)	ITLAB-103	-51.1

From the examples above, it is derived that the total yield of TDAE according to the process of the present disclosure is significantly higher than the yield according to the conventional process (only extraction with furfural):

Total Yield (%wt)

Example 1 2 3 4 5 6

Conventional Process 40% 40% 40% 40% 40% 40%

Process of the invention 61% 73% 65% 73% 57% 54%
The partial yields of hydrotreatment+fractionation and extraction of the examples above are as follows:

Process Stage Yield (%wt)

Example 1 2 3 4 5 6

HDT+fractionation 70% 75% 60% 92% 56% 56%

Extraction 51% 73% 70% 61% 52% 43%

REFERENCES CITED IN THE APPLICATION

EU Substance Directive 67/548/EEC
WO0071643
ASTM D-445
ASTM D-611
ASTM D-2140
IP-346
ASTM D-1250
ASTM D-1747
ASTM D-97
ASTM D-4294
ASTM D-2887
ASTM D-5453
ITLAB-103 Apto. B
ITLAB-103 Apto. C

Claims

A process for producing an extender process oil having a kinematic viscosity at 100 °C from 16 to 30 cSt determined in accordance with ASTM D-445, an aniline point from 55 to 80 °C determined in accordance with ASTM D-611, a content of polycyclic aromatics of less than 3 %wt determined in accordance with the IP-346 method, a Tg minimum of -56 °C determined in accordance with DSC, and an aromatic content higher or equal to 24 % wt. determined in accordance with ASTM D-2140; the process comprising:
a) providing a process oil educt that has a content of polycyclic aromatics from 3% w/w to 55 % w/w, determined in accordance with IP346, and a kinematic viscosity at 100°C from 16 to 250 cSt determined in accordance with ASTM D-445; the process oil educt comprises at least one of a primary extract or a secondary extract, the providing comprising
a.1) obtaining the primary extract by solvent extraction of vacuum distillates in the lubricating base oil preparation; and

a.2) obtaining the secondary extract by solvent extraction of the primary extract as obtained in a.1) with a solvent or a mixture of solvents, where at least one solvent is a polar extraction solvent;

b) hydrotreating the process oil educt; wherein the hydrotreatment is carried out at a temperature from 300 to 380 °C, a pressure from 40 to 200 bar and a liquid space velocity from 0.1 to 1.5 h-1, to provide a hydrotreated oil stream;

c) vacuum fractionating the hydrotreated oil stream obtained in step b), wherein the vacuum fractionating step is carried out in a vacuum tower obtaining a heavier fraction where the 5% according to ASTM D-2887 is from 400 to 465 °C and a gap equal or higher than -35 °C; being the gap defined as the difference between the 5% of the heavier fraction and the 95% of lights, the temperatures measured according to ASTM D-2887, to provide a vacuum fractionated hydrotreated oil stream having a viscosity at 100 °C from 16 to 60 cSt; and

d) contacting the vacuum fractionated hydrotreated oil stream obtained in step c) with a solvent or a mixture of solvents, where at least one solvent is a polar extraction solvent, in an extraction unit and performing a liquid-liquid extraction process; wherein order of steps c) and d) may be interchangeable; obtaining the extender process oil which meets simultaneously all the above mentioned technical specifications.
The process according to claim 1, wherein a counter-solvent or a mixture of counter-solvents is added to the extraction unit or alternatively it is mixed with the extraction unit feed.
The process according to any of claims 1-2, wherein an anti-solvent is added to the solvent or mixture of solvents.
The process according to any of claims 1-3, wherein in step d) a extract is obtained, and at least a part of this extract is recirculated to the hydrotreatment step b) and used as feed to the hydrotreatment step b).
The process according to any of claims 1-4, which further comprises the step of mixing the vacuum fractionated hydrotreated oil stream obtained in step c) with a primary extract, previously to the liquid-liquid extraction step d), wherein the primary extract is obtainable by solvent extraction of vacuum distillates in the lubricating base oil preparation.
The process according to any of claims 1-5, wherein the hydrotreatment step is carried out at a temperature from 320 to 370 °C, a pressure from 45-75 bar, and a liquid space velocity from 0.25-0.8 h-1.
The process according to any of claims 1-6, wherein the polar solvent of the liquid-liquid extraction step d) is selected from furfural, N-methylpyrrolidone, dimethylsulfoxide, N-N-dimethylformamide, methylcarbonate and morpholine.
The process according any of claims 1-7, wherein the ratio of total solvent content to extraction unit feed obtained in step c) is from 0.5 to 4.
The process according to any of claims 1-8, wherein the hydrotreatment step b) is carried out in presence of a hydrotreating catalyst based on a nickel, cobalt, molibdenum, chromium, vanadium, tungsten, phophorous, nickel-cobalt, nickel-molybdenum, cobalt-molybdenum, chromium-vanadium catalyst, a metal oxide catalyst, a metal sulfide catalyst, or a mixture thereof.
The process according to any of claims 1-9 wherein the vacuum fractionating is carried out in a vacuum tower obtaining a heavier fraction where the 5% according to ASTM D-2887 is from 410 to 455 °C, and a gap equal or higher than -35 °C to provide a vacuum fractionated hydrotreated oil stream having a viscosity at 100 °C from 16 to 60 cSt.