Process For Separating Used Oil

Abstract

A process for removing impurities from used oil. Impurities such as water, solid particles, and the like are removed from used oil by processing the oil with a mixture of polar and non-polar solvents. The process operates at room temperatures and pressures, simplifying the equipment and energy requirement for the process.

1 . A method for separating impurities from used oil comprising:
 selecting a used oil;   selecting a polar solvent;   selecting a non-polar solvent;   mixing the used oil, polar solvent, and non-polar solvent; and   separating solid impurities from the mixture of used oil polar solvent, and non-polar solvent.   
     
     
         2 . The method of  claim 1 , wherein the mixing step comprises mixing the polar solvent and non-polar solvent into a solvent mixture and thereafter mixing the solvent mixture with the used oil. 
     
     
         3 . The method of  claim 2 , wherein the mixing step comprises mixing the polar solvent and non-polar solvent to create a solvent mixture having between 5 and 15 percent non-polar solvent and the balance polar solvent. 
     
     
         4 . The method of  claim 3 , wherein the mixing step comprises mixing the polar solvent and non-polar solvent to create a solvent mixture having about 10 percent non-polar solvent and about 90 percent polar solvent. 
     
     
         5 . The method of  claim 2 , wherein the method comprises mixing the solvent mixture and used oil to create a mixture having between 15 and 50 percent used oil and between 50 and 85 percent solvent mixture. 
     
     
         6 . The method of  claim 1 , wherein the polar solvent is a ketone. 
     
     
         7 . The method of  claim 1 , wherein the polar solvent is acetone. 
     
     
         8 . The method of  claim 1 , wherein the non-polar solvent is an alkane. 
     
     
         9 . The method of  claim 7 , wherein the non-polar solvent is hexane. 
     
     
         10 . The method of  claim 1 , wherein the mixture of used oil, polar solvent, and non-polar solvent comprises between 2 and 13 percent non-polar solvent, between 42 and 81 percent polar solvent, and between 15 and 50 percent used oil. 
     
     
         11 . The method of  claim 10 , wherein the non-polar solvent is hexane and the polar solvent is acetone. 
     
     
         12 . A method for separating impurities from used oil comprising:
 selecting a polar solvent;   selecting a non-polar solvent;   mixing the polar solvent and non-polar solvent to form a solvent mixture;   selecting a used oil having solid impurities therein;   mixing the solvent mixture with the used oil to form a used oil mixture; and   separating the solid impurities from the used oil mixture so as to form a processed oil mixture.   
     
     
         13 . The method of  claim 12 , wherein the method further comprises separating the solvent mixture from the processed oil mixture so as to recover the solvent mixture. 
     
     
         14 . The method of  claim 13 , wherein the method further comprises using the recovered solvent mixture to treat additional used oil. 
     
     
         15 . The method of  claim 12 , wherein the step of separating the solid impurities comprises allowing the impurities to settle out of the used oil mixture. 
     
     
         16 . The method of  claim 12 , wherein the step of separating the solid impurities comprises passing the used oil mixture through a filter. 
     
     
         17 . The method of  claim 12 , wherein the polar solvent is a ketone. 
     
     
         18 . The method of  claim 12 , wherein the non-polar solvent is an alkane. 
     
     
         19 . The method of  claim 12 , wherein the polar solvent is acetone and wherein the non-polar solvent is hexane.