Patents

The invention provides an improved process for the preparation of biodiesel from crude vegetable oils especially Jatropha (Jatropha curcas) and Karanja (Pongamia pinnata). The invention bio-active constituents, fatty acids and polar materials are selectively removed from the crude oils by liquid-liquid extraction with a polar solvent into the solvent phase in a non-destructive manner in specially designed equipment either in a batch mode or continuous mode and the oil left as residue is amenable for direct transesterification. After transesterification, the glycerol phase is separated and the crude biodiesel is neutralised, and purified by adsorption of undesirable constituents like the residual glycerol, gums, soap, salts etc over a bed of adsorbent like Celite thereby circumventing the conventional water washing step. An alternative to the adsorbent method, the crude ester obtained after transesterification is purified using partition with aqueous solvent to biodiesel which meets the International specifications.