Production of biodiesel

Abstract

A process for the production of biodiesel is disclosed. In a preferred embodiment, the process is based on the production of biodiesel using refinery soapstock where the process is performed in an alcoholic medium resulting in the insolubility of certain byproducts. Other valuable products can also be obtained from the process.

1 . A process for producing biodiesel comprising: 
 saponifying a soapstock with an alkaline base in an alcohol to yield a saponified soapstock;    filtering the solution of saponified soapstock to remove substantially insoluble organic material;    adding a mineral acid to the filtered solution of saponified soapstock to form fatty acids and a mineral salt; and    esterifying the fatty acids, thereby forming biodiesel.    
   
   
       2 . The process of  claim 1 , further comprising neutralizing excess mineral acid after addition of the mineral acid to the filtered solution.  
   
   
       3 . The process of  claim 2 , further comprising removing salts formed from the neutralization.  
   
   
       4 . The process of  claim 1 , further comprising removing the alcohol after esterification.  
   
   
       5 . The process of  claim 4 , wherein the removal of alcohol is performed by distillation.  
   
   
       6 . The process of  claim 1 , further comprising removing insoluble impurities after esterification.  
   
   
       7 . The process of  claim 6 , wherein the removal of insoluble impurities is performed by centrifugation or filtration.  
   
   
       8 . The process of  claim 1 , further comprising distilling the esters of fatty acids after esterification.  
   
   
       9 . The process of  claim 1 , wherein the soapstock originated from refining of an oil selected from the group consisting of soy oil, rice oil, sunflower oil, coconut oil, castor oil, chicken oil, cottonseed oil, corn oil, peanut oil, palm oil, and babassu oil.  
   
   
       10 . The process of  claim 1 , wherein the alcohol is methyl alcohol or ethyl alcohol.  
   
   
       11 . The process of  claim 1 , wherein the alkaline base is sodium hydroxide or potassium hydroxide.  
   
   
       12 . Biodiesel obtained from a process comprising: 
 saponifying a soapstock with an alkaline base in an alcohol to yield a saponified soapstock;    filtering the solution of saponified soapstock to remove substantially insoluble organic material;    adding a mineral acid to the filtered solution of saponified soapstock to form fatty acids and a mineral salt; and    esterifying the fatty acids.    
   
   
       13 . Sterols obtained from a process comprising: 
 saponifying a soapstock with an alkaline base in an alcohol to yield a saponified soapstock;    filtering the solution of saponified soapstock to remove substantially insoluble organic material;    adding a mineral acid to the filtered solution of saponified soapstock to form fatty acids and a mineral salt;    esterifying the fatty acids;    removing insoluble impurities after the esterification; and    distilling the solution of esters of fatty acids after esterification to obtain sterols.    
   
   
       14 . The sterols of  claim 13 , wherein the distillation step is performed by thin film evaporation or falling film evaporation.  
   
   
       15 . The sterols of  claim 14 , wherein the process further comprises short-path distilling the product of distillation of the solution of esters of fatty acids.  
   
   
       16 . The sterols of  claim 15 , wherein the process further comprises crystallizing the product obtained by short-path distillation.  
   
   
       17 . Organic material obtained from a process comprising: 
 saponifying a soapstock with an alkaline base in an alcohol to yield a saponified soapstock; and    filtering the solution of saponified soapstock to obtain substantially insoluble organic material.    
   
   
       18 . Mineral salts obtain from a process comprising: 
 saponifying a soapstock with an alkaline base in an alcohol to yield a saponified soapstock;    filtering the solution of saponified soapstock to remove substantially insoluble organic material;    adding a mineral acid to the filtered solution of saponified soapstock to form fatty acids and a mineral salt; and    separating the mineral salt from the solution.