Resumen
Process for obtaining aromatic oils having a polycyclic aromatic compounds content of less than 3 %, useful as rubber extenders, from the mixed extract flow obtained in the manufacture of lubricant bases, which comprises cooling the flow of mixed extracts to render non-polyaromatic components insoluble, settling to bring about separation of the bases, total or partial redissolution in solvent of the light phase obtained in said settling, cooling to effect separation of the non-polyaromatic components, and settling to recover the light phase having a low polyaromatic compound content. A hydrocarbonated stream, having an initial boiling point greater than 200 DEG C, to regulate the solvent/solute rate and increase the production capacity of aromatic oils with a PCA content of less than 3%, may be added to the starting mixed extract flow. <IMAGE>
Reivindicaciones
1. Process for obtaining aromatic oils with a polycyclic aromatic compounds content of less than 3% (IP-346) from the mixed extract flow obtained in the manufacture of lubricant base oils, a flow which contains a polar solvent, preferably of the group comprising phenol, furfural and N-methyl-2-pyrrolidone, preferably furfural, characterized in that it comprises the stages of: a) cooling the flow of mixed extract to render non-polyaromatic components insoluble, b) settling to bring about separation of the phases, c) total or partial redissolution in solvent of the light phase obtained from the settling in stage b), d) cooling to effect separation of the non-polyaromatic components, and e) settling to recover the light phase having a low polyaromatic compounds content. 2. Process according to Claim 1, characterized in that the light phase obtained in stage e) has a polyaromatic compounds content of less than 3% according to IP-346, an aromatic hydrocarbons + polar compounds content of more than 45% according to ASTM D-2007, a polyaromatic hydrocarbons content (US EPA 8270) which is very much less than that of the extracts in the state of the art, a mutagenicity index according to the modified Ames test which is less than 1, a lower viscosity than known extracts for a similar volatility level and viscosity indexes generally less than 75 in products having a 100°C viscosity of more than 12 cSt. 3. Process according to Claim 1, characterized in that an anti-solvent such as water is optionally added to the starting mixed extract flow to increase selectivity for polyaromatic compounds. 4. Process according to Claim 3, characterized in that the quantity of anti-solvent optionally added varies between 0.5 and 10%, and preferably between 0.5 and 5% and especially between 1 and 2.5%. 5. Process according to Claims 1 and 4, characterized in that the quantity of additional solvent in relation to the flow of the hydrocarbon phase in the mixed extract flow is always less than 1.5:1 and preferably less than 1:1. 6. Process according to Claim 1, characterized in that some of the solvent contained in the mixed extract flow is optionally removed before the cooling stage in order to achieve an approximately 50% distribution of solvent in the stages prior to settling. 7. Process according to Claim 1, characterized in that a hydrocarbonated stream, having an initial boiling point at 760 mm Hg greater than 200°C, preferably greater than 300°C, is optionally added to the starting mixed extract flow to regulate the solvent/solute rate and increase the production capacity. 8. Process according to claim 7, characterized in that the added hydrocarbonated stream can be a product obtained in any of the vaccuum destilation processes of the atmospheric residue , extraction with solvent, dewaxing or deasphalting. 9. Process according to Claim 1, characterized in that a counter-solvent is optionally added before the first cooling stage to increase the selectivity of the solvent contained in the mixed extract flow. 10. Process according to Claim 9, characterized in that the counter-solvent may be a hydrocarbon flow with a maximum boiling point of less than 160°C, preferably less than 140°C. 11. Process according to any one of Claims 1, 3, 6, 7 and 9, characterized in that the cooling temperature before the settling stages lies within the range 10 - 90°C, preferably within the range 10 - 60°C and in particular within the range 20 - 50°C. 12. Process according to any one of Claims 1, 3, 6, 7 and 9, characterized in that in the case of aromatic extracts originating from deasphalted vacuum bottoms the use of additional solvent is optional. 13. Aromatic oils which can be regarded as being without carcinogenic potential, obtained in accordance with the process in Claims 1 to 10 from aromatic extracts obtained from vacuum distillates or deasphalted bottoms characterized in that they have the following properties: a) Viscosity at 100°C within the range 2 - 70 cSt, b) Viscosity indexes generally below 75 in oils having a viscosity of more than 12 cSt (100°C), c) Polyaromatic compounds content less than 3% by weight (IP-346), d) Lower polyaromatic hydrocarbons (PAH) content (US EPA-8270) than the aromatic extracts in the state of the art, e) Mutagenicity index according to the modified Ames test (ASTM E-1687-95) very much less than 1, f) Lower viscosity than, but volatility similar to the aromatic oils in the state of the art, g) Aromatic hydrocarbons + polar compounds content more than 45% (ASTM D-2007) and preferably in the range 60 - 90%. 14. Use of aromatic oils having a low polyaromatic compounds content according to Claim 13 as process oils and particu-larly as rubber extenders. 15. Use according to Claim 14 as rubber extenders having a high percentage of aromatic groups. 16. Use according to Claims 14 and 15 as styrene-butadiene rubber extenders. 17. Rubbers extended with the aromatic oils obtained according to the process in Claims 1 to 12 or described in Claim 13.
