Process for recovering used lubricating oils using clay and centrifugation

Abstract

A process for recovering used lubricating oils, and oils recovered using the process. In a first embodiment (for used industrial oils), the used lubricating oil is mixed with clay in a reactor. The mixture is preferably heated to between 80 and 200 degrees Celsius. The temperature should not be too great, to avoid “cracking” the oil (i.e., breaking molecular chains in the oil). After a certain period of time, the mixture is pumped through filters. Cakes of clay and contaminants remain in the filters, while the oil emerges without the contaminants. A second embodiment (for removing ash or soot, very fine carbon particles and other organic compounds from used motor oils) is the same as the first embodiment, except that before the mixture is passed through the filters, a centrifuge is used to remove most of the clay contaminated with soot, so that it will not block the filters.

1 . A process for recovering used lubricating oil, comprising the steps of:
 a) placing used lubricating oil and clay in a container where they are put together in contact to form a mixture;   b) heating the mixture to a suitable temperature for good sorption, with low effect of cracking; and   c) removing and separating the lubricating oil from waste products containing the clay and contaminants of the used lubricating oil;   wherein a filter press system is used to separate the lubricating oil from the clay and contaminants, to form a clay cake that is discarded, obtaining oil essentially free from contaminants, without the use of other substances to remove the contaminants from the used lubricating oil.   
   
   
       2 . The process for recovering used lubricating oil according to  claim 1 , wherein the used lubricating oil is pre-filtered before forming the mixture with the clay. 
   
   
       3 . The process recovering used lubricating oil according to  claim 2 , wherein the used lubricating oil is pre-treated with a flash type distillation, to separate a water residue from the used lubricating oil. 
   
   
       4 . The process for recovering used lubricating oil according to  claim 3 , wherein the mixture is heated with a system including a heating jacket, wherein hot hydraulic fluid circulates to transfer heat. 
   
   
       5 . The process for recovering used lubricating oil according to  claim 4 , wherein the clay is acid-activated. 
   
   
       6 . The process for recovering used lubricating oil according to  claim 5 , wherein the clay is a hybrid of hormite and smectite. 
   
   
       7 . The process for recovering used lubricating oil according to  claim 6 , wherein the container is a reactor, the hydraulic oil comes from a boiler, and a residence time in which the mixture remains in the reactor varies according the type of used lubricating oil. 
   
   
       8 . The process for recovering used lubricating oil according to  claim 7 , wherein the mixture is heated to temperatures lower than 300 degrees Celsius. 
   
   
       9 . The process for recovering used lubricating oil according to  claim 8 , wherein the mixture is heated to temperatures from 80 degrees Celsius to 200 degrees Celsius. 
   
   
       10 . The process for recovering used lubricating oil according to  claim 9 , wherein after the residence time in the reactor, the mixture is poured out, and treated by a separation process. 
   
   
       11 . The process for recovering used lubricating oil according to  claims 10 , wherein stirring rods are used to decrease the residence time of the mixture in the reactor. 
   
   
       12 . The process for recovering of used lubricating oil according to  claim 11 , wherein the volume of the clay is lower than 60% of the volume of the used lubricating oil. 
   
   
       13 . The process for recovering used lubricating oil according to  claim 12 , wherein the volume of clay is from 2% to 25% of the volume of the used lubricating oil. 
   
   
       14 . A process for recovering used lubricating oil, comprising the steps of:
 a) placing used lubricating oil and clay in a container where they are put together in contact to form a mixture;   b) heating the mixture to a suitable temperature for good sorption, with low effect of cracking; and   c) removing and separating the lubricating oil from waste products containing the clay and contaminants of the used lubricating oil;   wherein a centrifuge is used to separate the lubricating oil from the clay and contaminants, to form a clay cake that is discarded, obtaining oil essentially free from contaminants, without the use of other substances to remove the contaminants from the used lubricating oil.   
   
   
       15 . The process for recovering used lubricating oil according to  claim 14 , wherein a filter press system is used to separate the lubricating oils from the clays and contaminants, to form a clay cake that is discarded, obtaining oil essentially free from contaminants. 
   
   
       16 . The process for recovering used lubricating oil according to  claim 15 , wherein the centrifuge is an industrial centrifugal machine. 
   
   
       17 . The process for recovering used lubricating oil according to  claim 16 , wherein the centrifuge has a rotating screw, which allows it to separate most of the clay from the lubricating oil to be recovered.