Process for purifying oils and products produced from the purified oils

Abstract

Processes for purifying used cooking oil, and for isolating fractions from the used cooking oil that can be used in biodiesel and lubricant compositions, are described. Winterization of used cooking oil allows separation of particulate impurities, and the resulting oil can be further winterized to allow the oil to separate into fractions which include relatively higher and relatively lower FFA concentrations than the starting oil. Fractions can then be isolated, and those fractions with sufficiently low FFA concentrations can be used in biodiesel applications, and fractions with relatively higher FFA concentrations can be used in certain lubricant formulations, including chain saw lubricants and mould release oil compositions.

What is claimed is: 
     
         1 . A method of processing used cooking oil to recover material therefrom, wherein the used cooking oil has a first fatty acid concentration, said method comprising:
 a) cooling the used cooking oil to temperature between about −6° C. and about 10° C., and maintaining it at such temperature for a period of time between about 3 hours and about four weeks,   b) warming the used cooking oil to temperature between about 115° C. and 140° C.,   c) sedimenting solid impurities from the used cooking oil,   d) separating the oil from the sedimented solid impurities,   e) subjecting the separated oil to a winterization, and   f) isolating from the winterized oil a fraction with a second fatty acid concentration, which is higher than the first fatty acid concentration, and a fraction with a third fatty acid concentration, which is lower than the first fatty acid concentration.   
     
     
         2 . The method of  claim 1 , wherein the separated oil is subjected to more than one winterization. 
     
     
         3 . The method of  claim 1 , wherein the solid impurities are used as a diluent or a plasticizer for roofing tars or asphalts. 
     
     
         4 . The method of  claim 1 , wherein the used cooking oil comprises water, and the method further comprises removing water from the used cooking oil prior to said cooling a). 
     
     
         5 . The method of  claim 4 , wherein the water is removed using a heating and settling process, comprising heating the oil to temperature above 120° C., and maintaining the oil at such temperature for a period of time of 36 hours or longer. 
     
     
         6 . The method of  claim 1 , wherein the winterization comprises cooling the oil to temperature of about 10° C., and maintaining it at such temperature for a period of time between about two and four weeks. 
     
     
         7 . The method of  claim 1 , wherein one or more of the oil fractions includes a higher free fatty acid concentration than a predetermined amount for a given application, further comprising removing fatty acids therefrom. 
     
     
         8 . The method of  claim 7 , wherein the fatty acids are removed via neutralization and extraction, or via filtration through clay. 
     
     
         9 . A lube base stock prepared by the method of  claim 1 . 
     
     
         10 . A chain saw lubricant comprising a lube base stock prepared by the method of  claim 1 . 
     
     
         11 . The chain saw lubricant of  claim 10 , further comprising one or more additives selected from the group consisting of tackifiers, pour point depressants, anti-wear additives, rust inhibitors, and antioxidants. 
     
     
         12 . The chain saw lubricant of  claim 11 , comprising a pour point depressant at concentration of about 1.5% by weight, an anti-wear additive at concentration of between 0.1 and 1% by weight, an antiwear additive at a concentration of between 0.1 and 1% by weight, a rust protector between 0.1 and 1% by weight, and an antioxidant at concentration between 0.1 and 1% by weight, wherein all weight percentages are based on total weight of the chain saw lubricant. 
     
     
         13 . A mould release fluid comprising a lube base oil prepared according to the method of  claim 1 . 
     
     
         14 . The mould release fluid of  claim 13 , wherein the mold release fluid comprises a lube base oil, an organic solvent, a tackifier, between 0.1 and 1% by weight of a rust inhibitor, between 0.1 and 1% by weight of an antioxidant, and optionally between 0.1 and 3% by weight of a demulsifier and/or between 0.1 and 1% by weight of an odorant, wherein all weight percentages are based on total weight of the mold release fluid.