Method for recycling waste engine oil

Abstract

The present application relates to a technical field of recycling a waste engine oil, and discloses a method for recycling a waste engine oil, including adding an alkaline solution to the waste engine oil for treating the waste engine oil, to obtain a raw material oil; performing a first distillation for the raw material oil to obtain an intermediate oil; performing a second distillation for the intermediate oil to obtain an unevaporated intermediate oil as a residual oil product and an evaporated intermediate oil; fractionating the evaporated intermediate oil to obtain a first base oil component, a second base oil component and a third base oil component; and refining the first base oil component, the second base oil component and the third base oil component individually, to obtain a first refined oil, a second refined oil and a third refined oil.

What is claimed is: 
     
         1 . A method for recycling a waste engine oil, comprising the following steps:
 adding an alkaline solution to the waste engine oil for treating the waste engine oil, maintaining a treating temperature of 80-120° C., to obtain a raw material oil;   performing a first distillation for the raw material oil at a temperature of 240-270° C. to obtain an intermediate oil;   performing a second distillation for the intermediate oil at an absolute pressure of 0-3 kPa and a temperature of 300-350° C., to obtain an unevaporated intermediate oil as a residual oil product and an evaporated intermediate oil;   fractionating the evaporated intermediate oil to obtain a first base oil component, a second base oil component and a third base oil component; and   refining the first base oil component, the second base oil component and the third base oil component individually, to obtain a first refined oil, a second refined oil and a third refined oil.   
     
     
         2 . The method for recycling a waste engine oil according to the  claim 1 , wherein the alkaline solution is added in an amount of 0.5-1% by mass of the waste engine oil. 
     
     
         3 . The method for recycling a waste engine oil according to the  claim 2 , wherein the alkaline solution comprises at least one of a sodium hydroxide solution or a potassium hydroxide solution. 
     
     
         4 . The method for recycling a waste engine oil according to the  claim 1 , wherein the refining comprises adding an adsorbent to the first base oil component, the second base oil component and the third base oil component, respectively, under stirring, and filtering to obtain the first refined oil, the second refined oil and the third refined oil. 
     
     
         5 . The method for recycling a waste engine oil according to the  claim 4 , wherein the adsorbent is an activated clay. 
     
     
         6 . The method for recycling a waste engine oil according to the  claim 5 , wherein the refining comprises stirring at a temperature of 110-120° C. and an absolute pressure of 10-30 kPa for 30-60 min. 
     
     
         7 . The method for recycling a waste engine oil according to the  claim 4 , wherein the adsorbent is a decolorizing sand. 
     
     
         8 . The method for recycling a waste engine oil according to the  claim 7 , wherein the refining comprises stirring at room temperature for 40-60 min.