Liquid biofuel made of esters and bound glycerides, and also process for production thereof

Abstract

The present invention relates to a biofuel and to a process for production thereof, which biofuel contains at least one fraction of triglycerides, a fraction of monoglycerides, a fraction of diglycerides and a fraction of alkylesters of fatty acids. The biofuel may be obtained by partial transesterification of vegetable oil or vegetable fat and is distinguished in that the mass fraction of alkylesters of fatty acids in the biofuel is smaller than the mass fraction of triglycerides. The fuel is suitable in particular as additive for conventional fuels, may be produced at high yield and can also be used at relatively low temperatures below 10° C.

1 . Biofuel that contains at least one fraction of triglycerides, a fraction of monoglycerides, a fraction of diglycerides and a fraction of alkylesters of fatty acids,
 characterized in that   the mass fraction of alkylesters of fatty acids in the biofuel is smaller than the mass fraction of triglycerides.   
     
     
         2 . The biofuel according to  claim 1 ,
 characterized in that   the ratio of mass fractions of diglycerides to monoglycerides is ≧2.   
     
     
         3 . The biofuel according to either of  claim 1  or  2 ,
 characterized in that 
 the mass fraction of alkylesters of fatty acids is not less than 15% and not more than 35%. 
 
     
     
         4 . The biofuel according to either of  claim 1  or  2 ,
 characterized in that 
 the mass fraction of triglycerides is at least 30%. 
 
     
     
         5 . The biofuel according to  claim 4 ,
 characterized in that   the mass fraction of triglycerides is greater than 40%.   
     
     
         6 . The biofuel according to  claim 5 ,
 characterized in that   the mass fraction of triglycerides is not more than 65%.   
     
     
         7 . The biofuel according to either of  claim 1  or  2 ,
 characterized in that 
 the mass fraction of monoglycerides is between 0.1% and 10%. 
 
     
     
         8 . The biofuel according to either of  claim 1  or  2 ,
 characterized in that 
 the mass fraction of diglycerides is between 4% and 30%. 
 
     
     
         9 . The biofuel according to  claim 1 ,
 characterized in that   the mass fraction of alkylesters of fatty acids is between 20% and 25%, the mass fraction of triglycerides is between 50% and 55%, the mass fraction of diglycerides is 20%, and the mass fraction of monoglycerides is 5%.   
     
     
         10 . The biofuel according to  claim 1 ,
 characterized in that   the biofuel contains an additive of ethanol having a mass fraction of up to 2%.   
     
     
         11 . The biofuel according to  claim 1 ,
 which is mixed with fossil fuel, biodiesel or BTL-fuel.   
     
     
         12 . Use of the biofuel according to  claim 1  as a fuel for internal combustion engines. 
     
     
         13 . Process for producing the biofuel according to any of  claims 1  to  11  by partial transesterification of triglycerides, wherein at least one fraction each is obtained consisting of triglycerides, monoglycerides, diglycerides, and alkylesters of fatty acids,
 characterized in that 
 the partial transesterification is carried out in such manner that the mass fraction of alkylesters of fatty acids in the biofuel is smaller than the mass fraction of triglycerides. 
 
     
     
         14 . The process according to  claim 13 ,
 characterized in that   the partial transesterification is carried out in such manner that the ratio of mass fractions of diglycerides to monoglycerides is ≧2.   
     
     
         15 . The process according to either of  claim 13  or  14 ,
 characterized in that 
 carrier-bound sn-1,3 regiospecific lipases are used as the catalyst for partial transesterification. 
 
     
     
         16 . The process according to  claim 15 ,
 characterized in that   the partial transesterification is completed with gradual addition of enzymes over the course of several discontinuous production cycles.   
     
     
         17 . The process according to either of  claim 13  or  14 ,
 characterized in that 
 alcohol is added in sub-stoichiometric quantity for the transesterification. 
 
     
     
         18 . The process according to  claim 17 ,
 characterized in that   alcohol is added continuously or in several steps during the transesterification.   
     
     
         19 . The process according to  claim 18 ,
 characterized in that   when alcohol is added in several steps, an alcohol concentration of 3% by mass is not exceeded.   
     
     
         20 . The process according to either of  claim 13  or  14 ,
 characterized in that 
 for transesterification, alcohol is first dissolved in a reaction mixture that is largely free from lipases and contains the triglycerides, and that the reaction mixture is not brought into contact with the lipases as the catalyst until the alcohol has been completely dissolved. 
 
     
     
         21 . The process according to  claim 20 ,
 characterized in that   an alcohol concentration of ≦5% by mass is adjusted in the reaction mixture before it is brought into contact with the lipases.   
     
     
         22 . The process according to either of  claim 13  or  14 ,
 characterized in that 
 the partial transesterification takes place with vegetable oil or vegetable fat as the triglycerides.