EP3121254A1 - Lubricant purification and preparation of anti-rutting additive - Google Patents

Abstract

The invention relates to the field of purification of hydrocarbon feeds comprising one or more compounds to be removed, in particular used lubricating compositions. The invention also relates to a rutting resistance additive for bitumen prepared according to a process for purifying a hydrocarbon feedstock, comprising one or more compounds to be eliminated and a purified oil whose viscosity ranges from 50 to 400 mm 2. .s -1.

Description

The invention relates to the field of purification of hydrocarbon feeds comprising one or more compounds to be removed, in particular used lubricating compositions. The invention also relates to a rutting resistance additive for bitumen prepared according to a process for purifying a hydrocarbon feedstock, comprising one or more compounds to be eliminated and a purified oil whose viscosity ranges from 50 to 400 mm ^2. .s ^-1 .

In use, the lubricating compositions are degraded and then comprise pollutant compounds, undesirable or to be eliminated. Thus, used oils, such as motor oils, hydraulic oils, gear oils or industrial oils and mixtures thereof, must be purified to regenerate them into a lubricating base of commercial quality identical to the original product. for a new use. This type of treatment may be referred to as the re-refining or regeneration of waste oils. The field of the invention is therefore that of the regeneration of hydrocarbon feedstocks, such as waste or used oils, in particular engine oils, hydraulic oils, gear oils or industrial oils, and mixtures thereof.
The invention also makes it possible to produce substances that can be reused according to their properties obtained from the purification of used oils.

During their use, the oils are subjected to stresses that will cause their degradation leading to an increase in the level of contaminating elements these oils, these contaminants may be derived from a degradation of the additives present in the lubricant compositions, such as the antioxidant additives; anti-wear agents; or external pollutants, such as dust; or wear metals emanating from, for example, parts with which the oil is in contact during use; or even fractions of fuel (gas oil or gasoline) more or less oxidized or thermally cracked and which may be in liquid or solid form including soot; or else contaminants related to the storage of used oils in which there are sometimes substances constituting light fractions which are generally water or chlorinated or petroleum solvents.

This results in a polluted oil with a stronger coloration than the original clean oil, hence the name of black oils in the field of waste oils, in particular because of the presence of oxidation products or cracking fuel. In order to be reusable, the oil must be freed from these contaminants and, for this purpose, is required to undergo depollution operations generally similar to those of refining.
Methods are known for purifying used oils or waste oils. However, these methods have disadvantages and are therefore not satisfactory. In particular, the known processes do not make it possible to valorize all the products resulting from the purification of used oils or during the purification of used oils.
In addition, these processes require large deposits of used oils and are not suitable for small territories or isolated territories.

The invention thus provides a method for providing a solution to all or part of the problems of the methods of the state of the art.

1. a) d'extraire des composés légers présents au sein de la charge ;
2. b) de filtrer les composés à éliminer, en présence d'un fluide à l'état supercritique ;
3. c) de séparer le rétentat comprenant des composés à éliminer et de traiter la charge filtrée au moyen d'un agent de transformation ;
4. d) de séparer la charge hydrocarbonée purifiée par distillation sous vide ou sous pression réduite et de séparer le résidu de distillation ;
5. e) de laver le résidu de distillation au moyen d'une solution aqueuse ;
6. f) de séparer la phase aqueuse et la phase organique du résidu de distillation lavé.

The invention relates to a method for purifying a hydrocarbon feed comprising one or more compounds to be eliminated, which comprises the successive steps:

1. a) extracting light compounds present in the load;
2. b) filtering the compounds to be removed, in the presence of a fluid in the supercritical state;
3. c) separating the retentate comprising compounds to be removed and treating the filtered feed with a transformation agent;
4. d) separating the purified hydrocarbon feedstock by distillation under vacuum or under reduced pressure and separating the distillation residue;
5. e) washing the distillation residue with an aqueous solution;
6. f) separating the aqueous phase and the organic phase from the washed distillation residue.

1. a) purification, par extraction des composés légers, de la charge hydrocarbonée ;
2. b) séparation, par filtration en présence d'un fluide à l'état supercritique, de la charge hydrocarbonée purifiée obtenue à l'étape a), et obtention d'un filtrat et d'un retentat ;
3. c) purification, par saponification, du filtrat obtenu à l'étape b);
4. d) séparation, par distillation sous vide ou sous pression réduite, du filtrat purifié obtenu à l'étape c) et obtention d'une charge purifiée et distillée et d'un résidu de distillation ;
5. e) lavage, au moyen d'une solution aqueuse, du résidu de distillation obtenu à l'étape d) ;
6. f) séparation du résidu de distillation lavé obtenu à l'issue de l'étape e) en une phase aqueuse et une phase organique.

According to one embodiment, the invention relates to a process for purifying a hydrocarbon feedstock, comprising the following steps:

1. a) purification, by extraction of the light compounds, of the hydrocarbon feedstock;
2. b) separating, by filtration in the presence of a fluid in the supercritical state, the purified hydrocarbon feedstock obtained in step a), and obtaining a filtrate and a retentate;
3. c) purification, by saponification, of the filtrate obtained in step b);
4. d) separating, by distillation under vacuum or under reduced pressure, the purified filtrate obtained in step c) and obtaining a purified and distilled feedstock and a distillation residue;
5. e) washing, with an aqueous solution, the distillation residue obtained in step d);
6. f) separating the washed distillation residue obtained at the end of step e) into an aqueous phase and an organic phase.

Advantageously, the process according to the invention applies to a hydrocarbon feedstock chosen from a mineral or mineral oil or a synthetic or synthetic oil. Preferably, the hydrocarbon feedstock is chosen from mineral oils resulting from the fractional distillation of crude oil, in particular industrial oils, gear oils, hydraulic oils or used or used motor oils.

Advantageously, the light compounds according to the invention are defined as being the volatile compounds contained in the hydrocarbon feedstock. This is for example water, gasoline, solvents, or a portion of the diesel cut.

Generally, the hydrocarbon feedstock treated according to the process of the invention comprises one or more hydrocarbons and optionally one or more compounds comprising carbon atoms, hydrogen and which may also comprise one or more heteroatoms. Generally, the hydrocarbon feedstock treated according to the process of the invention also comprises compounds to be eliminated selected from dispersant additives, detergent additives, anti-wear additives, polymers, soot, metal elements.

Preferably, step a) of extraction of the light compounds is carried out by distillation under vacuum or under reduced pressure. Advantageously, the extraction step a) is a flash evaporation of the light compounds.
According to a preferred embodiment, step a) of the process according to the invention makes it possible to purify the hydrocarbon feedstock by distillation, preferably by distillation of the light compounds.
Step a) of extraction of the process according to the invention also makes it possible to eliminate water or the aqueous phase which may be present within the hydrocarbon feedstock.

The extraction step a) is in particular carried out at a pressure of less than 0.08 bar, for example less than 0.05 bar, or even less than 0.03 bar. Generally, the extraction step a) is carried out at a temperature ranging from 100 to 250 ° C, for example at about 150 ° C.

According to the invention, step b) of filtration of the hydrocarbon feedstock obtained in step a) in the presence of a fluid in the supercritical state is preferably carried out by means of CO ₂ in the supercritical state although other gases, such as N ₂ O, SF ₆ , methane, ethane, propane or hexane, may be suitable. During step (b), the CO ₂ in the supercritical state is generally used in an amount ranging from about 2 to 60% or about 15 to 20% by weight of hydrocarbon feedstock to be purified.
In a preferred manner for the process according to the invention, step (b) is a tangential filtration. Also preferably for the process according to the invention, step (b) is carried out at a temperature ranging from 100 to 180 ° C or at a pressure ranging from 120 to 180 bar. It can be carried out at a temperature ranging from 100 to 180 ° C. and at a pressure ranging from 120 to 180 bar.
Step (b) is carried out by means of a filter which may be a membrane based on metals or metal alloys such as steel, for example stainless steel, or nickel; oxides such as oxides selected from Al ₂ O ₃ , ZrO ₂ , TiO ₂ .
Step (b) concerns the majority of the compounds to be removed, preferably 80% or even 90% or more of the compounds to be removed are filtered. Advantageously, the filter makes it possible to retain compounds or particles whose average size, ie the average particle diameter, ranges from 1 nm to 10 μm, preferably from 2 nm to 1 μm, and more preferred from 2 nm to 0.1 μm.
In a preferred manner according to the invention, step b) consists in the separation, by tangential filtration in the presence of CO ₂ in the supercritical state, of the hydrocarbon feedstock obtained in step a), and allows the obtaining a filtrate and a retentate.

Step b) makes it possible to separate the compounds to be eliminated present in the filtration retentate from the filtered hydrocarbon feedstock. The filtered hydrocarbon feedstock is then treated using the transformation agent.
Advantageously, the retentate obtained in step b) comprising compounds to be eliminated can be concentrated. This concentration of the retentate can be achieved by eliminating certain compounds, in particular paraffinic compounds.

Preferably, the filtrate obtained in step b) is purified in step c) of the feed by means of a transformation agent. Preferably, step c) is carried out by saponification. Preferably, the treatment c) by saponification is carried out using a transformation agent selected from NaOH or KOH, used alone or as a mixture. The saponification is preferably carried out using NaOH.
In a preferred manner according to the invention, step c) consists in the purification, by saponification using sodium hydroxide in aqueous solution at about 50% by weight, of the filtrate obtained in step b).

The step d) of separation of the purified filtrate obtained in step c) is carried out by vacuum distillation, for example by vacuum distillation with falling film or by distillation under reduced pressure in a thin layer. When performing a falling film distillation, the start-of-distillation parameters are advantageously about 19 mbar for the pressure, about 240 ° C for the medium temperature and about 50 ° C for the medium temperature. the temperature at the top of the column. At the end of distillation, these parameters are generally about 19 mbar for the pressure, about 375 ° C tending towards 400 ° C for the temperature of the medium and about 375 ° C for the temperature at the top of the column.
In a preferred manner according to the invention, step d) consists of the separation, by distillation under vacuum or under reduced pressure, of the purified filtrate obtained in stage c) and makes it possible to obtain a purified filler and distilled and a distillation residue. Advantageously, the purified and distilled feed obtained at the end of step (d) has characteristics identical to those of the base oils. This purified and distilled feedstock can therefore be used as a base oil in lubricating compositions.

Step e) consists of washing the distillation residue obtained at the end of step d). In a preferred manner according to the invention, step e) consists in washing, by means of an aqueous solution, the distillation residue obtained in step d).
In step e), the distillation residue is treated with an aqueous solution. Preferably, step e) is carried out with water, for example in an amount ranging from 1 to 5 times, preferably from 1 to 3 times, the volume of distillation residue obtained. The mixture of the aqueous solution and the distillation residue can be stirred.
Step (e) can be carried out with varying amounts of aqueous solution. A mixture comprising 20, 30 or 50% by weight of distillation residue supplemented to 100% by weight with aqueous solution may be advantageous.

Step f) of the process of the invention consists of separating the aqueous and organic phases of the washed distillation residue obtained in step e). The separation of step f) can be carried out by decantation. Once the organic phase is separated, it can be dried. Advantageously, its viscosity measured at 100 ° C. according to the ISO 3104 standard ranges from 50 to 400 mm ² .s ^-1 , preferably from 100 to 200 mm ² .s ^-1 .
In a preferred manner according to the invention, step f) of the process consists of separating the washed distillation residue obtained in step e) into an aqueous phase and an organic phase.

The particular or preferred features of the method according to the invention can be combined with each other in ways to define variants of the method according to the invention. In particular, the specific combinations of the preferred characteristics define preferred variants of the process according to the invention.

1. a) d'extraire par distillation sous vide ou sous pression réduite, des composés légers présents au sein de la charge hydrocarbonée comprenant un ou plusieurs composés à éliminer ;
2. b) de filtrer les composés à éliminer de manière tangentielle en présence de CO₂ à l'état supercritique ;
3. c) de séparer le rétentat comprenant des composés à éliminer et de traiter la charge filtrée au moyen de soude en solution aqueuse à environ 50% en masse ;
4. d) de séparer les composés transformés de la charge hydrocarbonée purifiée par distillation sous vide ou sous pression réduite et de séparer le résidu de distillation ;
5. e) de laver le résidu de distillation au moyen d'une solution aqueuse ;
6. f) de séparer la phase aqueuse et la phase organique du résidu de distillation lavé.

In a preferred manner, the process according to the invention comprises the successive steps:

1. a) extracting by distillation under vacuum or under reduced pressure, light compounds present in the hydrocarbon feedstock comprising one or more compounds to be removed;
2. b) filtering the compounds to be removed tangentially in the presence of CO ₂ in the supercritical state;
3. c) separating the retentate comprising compounds to be removed and treating the load filtered with soda in aqueous solution at about 50% by weight;
4. d) separating the transformed compounds from the purified hydrocarbon feedstock by distillation under vacuum or under reduced pressure and separating the distillation residue;
5. e) washing the distillation residue with an aqueous solution;
6. f) separating the aqueous phase and the organic phase from the washed distillation residue.

1. a) distillation de la charge hydrocarbonée ;
2. b) séparation, par filtration tangentielle tangentielle en présence de CO₂ à l'état supercritique, de la charge hydrocarbonée purifiée obtenue à l'étape a), et obtention d'un filtrat et d'un rétentat ;
3. c) purification, par saponification au moyen de soude en solution aqueuse à environ 50% en masse, du filtrat obtenu à l'étape b) ;
4. d) séparation, par distillation sous vide ou sous pression réduite, du filtrat purifié obtenu à l'étape c) et obtention d'une charge purifiée et distillée et d'un résidu de distillation ;
5. e) lavage, au moyen d'une solution aqueuse, du résidu de distillation obtenu à l'étape d) ;
6. f) séparation du résidu de distillation lavé obtenu à l'étape e) en une phase aqueuse et une phase organique.

According to a preferred embodiment, the method of the invention comprises the following steps:

1. a) distillation of the hydrocarbon feedstock;
2. b) separation, by tangential tangential filtration in the presence of CO ₂ in the supercritical state, of the purified hydrocarbon feed obtained in step a), and obtaining a filtrate and a retentate;
3. c) purification, by saponification with sodium hydroxide in aqueous solution at about 50% by weight, of the filtrate obtained in step b);
4. d) separating, by distillation under vacuum or under reduced pressure, the purified filtrate obtained in step c) and obtaining a purified and distilled feedstock and a distillation residue;
5. e) washing, with an aqueous solution, the distillation residue obtained in step d);
6. f) separating the washed distillation residue obtained in step e) into an aqueous phase and an organic phase.

• une première unité, par exemple une cuve, dans laquelle est placée la charge hydrocarbonée à purifier ;
• une unité de filtration reliée à la première unité ; et
• une unité de collecte du rétentat et une unité de collecte du filtrat de l'étape b) reliées toutes deux à l'unité de filtration.

Moreover, the method according to the invention can be implemented within an installation comprising at least:

• a first unit, for example a tank, in which is placed the hydrocarbon feedstock to be purified;
• a filtration unit connected to the first unit; and
• a retentate collection unit and a filtrate collection unit of step b) both connected to the filtration unit.

In a particularly advantageous manner, the process according to the invention makes it possible to purify a hydrocarbon feedstock comprising one or more compounds to be eliminated and to obtain a purified hydrocarbon feedstock. Preferably, this purified and distilled hydrocarbon feed obtained at the end of step d) can be used as a lubricant, in particular as a lubricant for a vehicle engine.

Also advantageously, the method according to the invention makes it possible to obtain a retentate at the end of step b). This retentate has particularly advantageous properties. Thus, the invention also relates to the use of this retentate prepared as a bitumen additive. Preferably, it is a rutting resistance additive for bitumen.
The invention also relates to the use of the retentate obtained at the end of step b) as an additive for the preparation of a road coating composition comprising at least one bitumen and this additive, preferably in an amount ranging from 1 to 10% by weight of composition. The bitumen can in particular be a 35/50 grade bitumen.
Also advantageously, the invention also relates to the use of the retentate obtained at the end of step b) for the preparation of a road coating composition comprising at least one bitumen and said retentate, preferably in one form. amount ranging from 1 to 10% by weight of composition.

During the preparation of a composition comprising at least one 35/50 grade bitumen and an additive obtained according to the invention, it is possible to obtain an additive bitumen of class 50/70.

Also advantageously, the process according to the invention makes it possible to obtain, after step f), the organic phase of the washed distillation residue. According to the invention, this organic phase of the distillation residue can advantageously be used as a lubricant, preferably as a lubricant for gears, for example for open gears. This lubricant has a viscosity measured at 100 ° C. according to the ISO 3104 standard ranging from 50 to 400 mm ² .s ^-1 , preferably from 100 to 200 mm ² .s ^-1 ,

The various aspects of the invention are illustrated by the following examples.

Example:

A mixture of used oils from motor oils, bridge oils and gearbox oils (5000 L) from heavy vehicles was processed according to the process of the invention. The used oil mixture is placed in a jacketed tank which is heated to 70 or 80 ° C and then heated by means of a heat exchanger (150 ° C).
The water present in the waste oil mixture is removed by flash distillation (150 ° C, 150 mbar) in a 50 L autoclave. Any light substances are then also separated from the oil mixture during evaporation. flash.
The waste oil mixture (4,600 L) obtained from the distillation is then filtered in the presence of CO ₂ in the supercritical state (150 ° C., 150 bar) in a quantity of approximately 20% by mass of the amount of used oils entering the device.
Fifteen microfiltration membranes (product Tami Dahlia 0.14 microns) are arranged in a recirculation loop equipped with a centrifugal pump of large volume capacity. The injection of used oil - CO ₂ mixture is made in the suction line of the centrifugal pump to maximize the mixing of the two components before filtration. The waste oil flow in the plant is 165 kg / h. The flow rate of the filtrate is about 125 kg / h. The difference between inner and outer pressures of the filtration membranes (ΔP) is less than 4 bar. A filtrate (2870 L) and a filtration retentate (1550 kg) are obtained.
The filtration retentate is reintroduced into the filtration loop. The treatment conditions are similar (150 ° C., 150 bar). The amount of CO ₂ is about 30% by weight of introduced retentate. The recirculation rate is about 30-31 m ³ / h. The charge rate is 50 kg / h and the retentate flow rate is about 43 kg / h.

The filtrate obtained during this reprocessing is mixed with the filtrate obtained during the filtration of the used oil mixture.
A total of 1,487 L filtrate and a filtration retentate (217 kg) are obtained. A retentate is obtained whose density mixed with CO ₂ is about 982 kg / m ³ (about 300 kg / m ³ mixed with CO ₂ ).
The physico-chemical characteristics of the used oil mixture, the retentate and the filtrate are presented in Table 1. The amounts (A in mg), concentration (B in% by weight) and abatement (C in% by weight) of the different chemical elements are also presented in Table 1. <u> Table 1 </ u> Blend of oils retentate filtrate Kinematic viscosity at 40 ° C 40.5 mm ² .s ^-1 431 mm ² .s ^-1 27.1 mm ² .s ^-1 Kinematic viscosity at 100 ° C 7.12 mm ² .s- ¹ 59.3 mm ² .s ^-1 5 mm ² .s ^-1 Viscosity index 138 209 109 Present elements (mg) A (mg) A (mg) B (%) A (mg) VS (%) Li 0 3 / 0 / B 119 605 508 66 44.5 N / A 60 372 620 8 86.7 mg 48 210 438 12 75.0 al 11 68 618 1 90.9 Yes 112 251 224 80 28.6 P 523 1,484 284 320 38.8 S 6434 9047 141 5194 19.3 K 50 324 648 8 84.0 It 874 5233 599 157 82.0 Ti 2 15 750 0 100.0 V 0 1 / 0 / Cr 2 16 800 0 100.0 mn 4 20 500 1 75.0 Fe 115 618 537 28 75.7 Or 1 6 600 1 0 Cu 17 63 371 9 47.1 Zn 526 2,132 405 197 62.5 MB 16 104 650 0 100.0 Ag 0 0 / 0 / CD 0 1 / 0 / Sn 1 6 600 0 100.0 Sb 0 0 / 0 / Ba 9 56 622 1 88.9 Pb 7 12 171 7 0 Bi 0 0 / 0 /

• ▪ spectrométries Infra-rouge,
• ▪ analyse élémentaire et teneurs en métaux,
• ▪ analyse élémentaire : carbone, hydrogène, soufre, azote, oxygène, métaux et métalloïdes,
• ▪ caractéristiques techniques: couleur, viscosité (plusieurs déterminations à températures variées), point d'écoulement, point éclair, résidu Conradson, teneur en eau, indice d'acide, indice d'iode, point d'aniline, distillation simulée et réelle des hydrocarbures, masse volumique.

A filtrate (2870 L) is obtained which is treated with sodium hydroxide (4% by weight relative to the amount of filtrate) in solution in water (4% by weight relative to the amount of filtrate) for 15 hours. hours, at a temperature of 100 ° C.
Then, the mixture is distilled at reduced pressure (50 mbar) at 290 ° C using a thin-film evaporator equipped with rigid scrapers.
Flash evaporation is then carried out (5 mbar) followed by distillation (5 mbar and 315 ° C.). A purified oil and a distillation residue are obtained.
The purified oil obtained after distillation is analyzed and compared with two commercial oils (a refined base oil and a regenerated base oil):

• ▪ Infra-red spectrometries,
• ▪ elemental analysis and metal contents,
• ▪ elemental analysis: carbon, hydrogen, sulfur, nitrogen, oxygen, metals and metalloids,
• ▪ technical characteristics: color, viscosity (several determinations at various temperatures), pour point, flash point, Conradson residue, water content, acid number, iodine number, aniline point, simulated and actual distillation hydrocarbons, density.

The characteristics and the properties of the purified oil obtained according to the invention are presented in Table 2. <u> Table 2 </ u> Kinematic viscosity at 40 ° C (NF EN ISO 3104) mm ² .s ^-1 29,16 Kinematic viscosity at 100 ° C (NF EN ISO 3104) mm ² .s ^-1 5,238 Viscosity index (NF ISO 2909 - calculation method B) / 111 Pour point (NFT 60-105) ° C -18 Open cup flash point (Cléveland) (NF EN ISO 2,592) ° C 228 Residue Conradson (NF EN ISO 10870) % m / m <10 Moisture content (Karl Fischer) % m / m <0.1 Acid number (NF EN ISO 6 618) mg (KOH) .g ^-1 0.01 Iodine number (NF EN ISO 3 961) g / 100 g 5.1 Aniline point (ASTM D611) ° C 106.40

The contents of polycyclic aromatic hydrocarbon compounds (PAHs) were analyzed by chromatography (HPLC and detection in UV-fluorimetry). They were compared with those obtained by analysis of a regenerated oil according to a method of the state of the art (oil EH). The results are shown in Table 3. <u> Table 3 </ u> PDT Regenerated oil
(Mg / kg) Tox Score Oil according to the invention
(Mg / kg) Tox Score naphthalene 0.40 0.0004 0.31 0.0003 acenaphthylene 0.50 0.0005 0.20 0.0002 acenaphtene 0.19 0.0002 0.05 5E-05 fluorene 0.61 0.0006 0.15 0.0002 phenanthrene 5.00 0.005 4.00 0,004 anthracene 0.42 0.0042 0.24 0.0024 fluoranthene 1.40 0.0014 1.50 0.0015 Pyrene 4.70 0.0047 5.50 0.0055 Benzo (a) anthracene 0.77 0.077 1.80 0.18 cHRYSENE 0.73 0.0073 1.10 0,011 Benzo (b) fluoranthene 3.40 0.34 1.50 0.15 Benzo (k) fluoranthene 0.50 0.05 0.33 0.033 Benzo (a) pyrene 4.40 4.4 0.49 0.49 Indeno 1,2,3 (c, d) pyrene 2.80 0.28 0.44 0.044 Dibenzo (a, h) anthracene 0.64 0.64 0.25 0.25 Dibenzo (g, h, i) perylene 13,00 0.13 3.50 0,035 Content extracted HAP 0.80 / 0.70 / TEQ (% by weight) / 5.9413 / 1.2071

The characteristics and properties of the purified oil obtained according to the invention are equivalent to or greater than those of the two oils. The base oil according to the invention can therefore be used in a lubricant composition, especially in a lubricant composition for a vehicle engine.

The distillation residue obtained after distillation was washed with water with stirring for 4 hours and then the organic phase was separated by decantation for 12 hours. A paraffin oil is obtained whose viscosity measured at 100 ° C. is 150 mm ² .s ^-1 . This oil can be used to lubricate gears, including open gears.

In addition, the filtration retentate was evaluated for its bitumen additive properties. The retentate is mixed with bitumen and its resistance properties within the mixture as well as the improvement of the properties of the additive bitumen were analyzed.
The program is established in two phases. The first concerns the behavior of the mixture of retentate and bitumen, before and after simulation of a coating. The measures are based mainly on the assessment of the consistency of the products, in accordance with the European regulatory specifications. The second phase deals with the coated material, made by mixing aggregates, bitumen and retentate. The compactibility, water stripping resistance and ability to resist rutting are evaluated.
The bitumen class chosen is 35/50. The rate of modification of the bitumen by the retentate was set at 2.5% by weight.

Complex modulus measurements show that the retentate and bitumen mixture is rheologically simple. This reflects a good compatibility of the two materials.
This bitumen-type asphalt, made with a 35/50 bitumen additive containing 2.5% by weight of retentate, complies with the level 2 specifications (for a Class 4 GB).
The mixture 35/50 bitumen and retentate (2.5% by weight) complies with the specifications of road bitumens and gives a gravel bitumen of class 4 compliant up to level 2.

A leaching test according to standard NF EN 12 457-2 has also been carried out. A 35/50 bitumen sand was compared to the same 35/50 bitumen sand additive with 2.5% retentate. The analysis of the eluate after leaching test shows a total organic carbon content (according to NF EN 1484) of 17 mg / kg for the reference sample and 31 mg / kg for the sample made from bitumen additive.
Both samples have a similar chromatographic profile free of semi-volatile organic molecules detectable by this technique. Consequently, the addition of ultrafiltration retentate to the bitumen does not alter its behavior on contact with water: no semi-volatile substance is detectable in the leachate.

A demixing resistance test was carried out for the additive bitumen of the retentate according to the invention.
The retentate mixed with the bitumen was placed in a vertical tube and then allowed to stand for 36 hours at 180 ° C. After cooling, the softening points of the mixture from the top and bottom of the tube were measured. Softening temperatures of 51.8 ° C are obtained for the mixture coming from the upper part and 51.4 ° C for the mixture coming from the upper part.
These very close temperatures confirm that no demixing took place. The additive bitumen of the retentate according to the invention is therefore storage stable.

The resistance to rutting of the additive bitumen of the retentate according to the invention was evaluated by means of a Gamma bank according to the method NF EN 12697 part 22.
The rutting results are very good for the additive bitumen of the retentate according to the invention. Indeed, while the average normative value of the rut depth after 10,000 passes must be less than 10%, the bitumen additive of the retentate according to the invention allows a value of 4.6%.

Claims (13)

A process for purifying a hydrocarbon feedstock, comprising the steps of: a) purification, by extraction of the light compounds, of the hydrocarbon feedstock; b) separating, by filtration in the presence of a fluid in the supercritical state, the purified hydrocarbon feedstock obtained in step a), and obtaining a filtrate and a retentate; c) purification, by saponification, of the filtrate obtained in step b); d) separating, by distillation under vacuum or under reduced pressure, the purified filtrate obtained in step c) and obtaining a purified and distilled feedstock and a distillation residue; e) washing, with an aqueous solution, the distillation residue obtained in step d); f) separating the washed distillation residue obtained in step e) into an aqueous phase and an organic phase. Process according to Claim 1, in which the hydrocarbon feedstock: Is chosen from a mineral or mineral oil or a synthetic or synthetic oil, preferably chosen from mineral oils resulting from the fractional distillation of crude oil, especially industrial oils, gear oils, used or used hydraulic oils or motor oils; or Comprises one or more hydrocarbons and optionally one or more compounds comprising carbon atoms, hydrogen atoms and which may also comprise one or more heteroatoms. Process according to one of claims 1 or 2, for which the hydrocarbon feedstock comprises compounds to be eliminated selected from dispersant additives, detergent additives, anti-wear additives, polymers, soot, metal elements. Process according to one of Claims 1 to 3, in which stage a) is carried out by distillation under vacuum or under reduced pressure. Process according to one of Claims 1 to 4, in which the fluid in the supercritical state used in step b), preferably CO ₂ , is present in an amount ranging from approximately 2 to 60% or approximately 15 to 20% by weight of hydrocarbon feedstock to be purified. Method according to one of claims 1 to 5, wherein step (b) is a filtration ▪ tangential; or ▪ carried out at a temperature ranging from 100 to 180 ° C or at a pressure ranging from 120 to 180 bar. Process according to one of Claims 1 to 6, in which step (c) is carried out using a compound chosen from NaOH or KOH, used alone or as a mixture. Method according to one of claims 1 to 7, wherein the retentate obtained in step b) is concentrated. Method according to one of claims 1 to 8, comprising the following steps: a) distillation of the hydrocarbon feedstock; b) separation, by tangential filtration in the presence of CO ₂ in the supercritical state, of the purified hydrocarbon feedstock obtained in step a), and obtaining a filtrate and a retentate; c) purification, by saponification with sodium hydroxide in aqueous solution at about 50% by weight, of the filtrate obtained in step b); d) separating, by distillation under vacuum or under reduced pressure, the purified filtrate obtained in step c) and obtaining a purified and distilled feedstock and a distillation residue; e) washing, with an aqueous solution, the distillation residue obtained in step d); f) separating the washed distillation residue obtained in step e) into an aqueous phase and an organic phase. Use of a purified hydrocarbon feedstock prepared according to one of claims 1 to 9 as a lubricant, in particular as a lubricant for a vehicle engine. Use of a retentate obtained in step b) of the process according to one of claims 1 to 9, as additive for bitumen, preferably as a rutting resistance additive for bitumen. Use of a retentate obtained in step b) of the process according to one of claims 1 to 9, for the preparation of a road coating composition comprising said retentate in an amount ranging from 1 to 10% by weight composition, and at least one bitumen. Use of the organic phase of the washed distillation residue obtained after step f) of the process according to one of claims 1 to 9, as a lubricant, in particular as a lubricant whose viscosity is measured at 100 ° C. according to the ISO 3104 standard ranges from 50 to 400 mm ² .s ^-1 , preferably from 100 to 200 mm ² .s ^-1 , for gears, for example for open gears.