JPWO2020160662A5 - - Google Patents

Claims (9)

Continuous liquid-liquid solvent extraction is performed by contacting a feedstock comprising refined used oil with an extraction solvent to produce an extract stream comprising said extraction solvent and extract dissolved in said extraction solvent. wherein said feedstock and said extraction solvent are agitated by a variable speed agitator during said solvent extraction at a selected agitation speed;
separating the extract from the extraction solvent;
subjecting the extract to continuous flow liquid phase hydrogenation treatment to produce an oil product having a viscosity index of at least 80;
A method, including The liquid phase hydrogenation treatment is
adding a diluent to the extract to increase the solubility of hydrogen in the extract to form a liquid mixture comprising the diluent and the extract;
adding hydrogen to the liquid mixture to dissolve the hydrogen in the liquid mixture;
heating the liquid mixture with dissolved hydrogen in the presence of a hydrogenation catalyst to saturate unsaturated materials in the liquid mixture, remove sulfur and aromatics from the liquid mixture, and produce the oil product; forming;
2. The method of claim 1, comprising: refining the used oil to produce said feedstock ;
3. The method of any one of claims 1-2 , wherein said refining comprises subjecting said used oil to distillation to form said feedstock comprising distillate from said distillation . forming a countercurrent flow of said feedstock and said extraction solvent in a solvent extraction column , wherein the agitation rate and flow rate of said feedstock and said extraction solvent entering said solvent extraction column are dependent on the quality or nature of said feedstock. 4. The method of any one of claims 1 to 3 , wherein the method is independently adjusted based on. a refinery configured to refine the spent oil to form a feedstock comprising the refined spent oil;
A continuous countercurrent liquid-liquid extraction column for extracting an extract from said feedstock using an extractant, said feedstock and extraction solvent passing through said extraction column being stirred at a variable agitation rate. an extraction column comprising an agitator configured;
a continuous flow liquid phase hydrogenation unit for hydrotreating the extract extracted by the extraction column to produce an oil product;
system, including The continuous flow liquid phase hydrogenation apparatus is
a hydrogenation reactor containing a hydrogenation catalyst;
a transport line in fluid communication with the solvent extraction column and the hydrogenation reactor for transporting the extract from the solvent extraction column to the hydrogenation reactor;
a diluent inlet on the transfer line for introducing diluent into the extract passing through the transfer line to form a liquid mixture comprising the extract and the diluent;
a hydrogen inlet on said transfer line located downstream of said diluent inlet for introducing hydrogen into said liquid mixture;
6. The system of claim 5 , comprising: The liquid phase hydrogenation apparatus further comprises a guard bed located on the transfer line between the diluent inlet and the hydrogen inlet, the guard bed removing at least phosphorus and silicon from the liquid mixture. 7. The system of claim 6 , configured to. 5. The method of any one of claims 1-4, wherein the extraction solvent comprises n-methyl-2-pyrrolidone. the refined used oil comprises refined used motor oil;
9. A process according to any one of claims 1 to 4 and 8, wherein the oil product comprises at least 90 wt% saturates, contains less than 0.03 wt% sulfur and has a viscosity index of at least 120.