31-05-2012, 03:10 PM
Biodiesel conclave
Biodiesel conclave.ppt (Size: 304 KB / Downloads: 92)
Basic Process
The basic process involves transesterification of vegetable oil/fats in presence of a catalyst in batch or continuous mode. Continuous process may not be suitable, if the variation in quality of feedstocks are wide.
There are numerous variations of basic technology:
Different catalysts e.g. NaOH, KOH, MeONa, Non alkaline catalysts, acids, metal complexes and bio catalysts etc. can be used.
Anhydrous ethanol, isopropanol or butanol can be substituted for methanol.
Alcohols other than methanol may require additional process steps and quality control.
Basic transesterification is carried out at atmospheric pressure and temperature around 60°-70°C.
Some technologies use higher temperatures and elevated pressure, typically in super critical range of methanol.
For high FFA feedstocks – acid catalysed esterification followed by base catalysed transesterification is used or FFA can be removed first and the purified oil is transesterified.
Problems of Biodiesel Production
Both base and acid catalyzed processes are associated with several inherent problems:
Free fatty acids interfere with transesterification deactivate the basic catalysts – loss of catalyst and biodiesel yield.
Water deactivates both basic and acidic catalysts. Drying of oil may be required.
Soaps formed with basic catalyst form emulsion and foam and difficult to remove.
When processing feed stocks with high free fatty acids additional steps must be taken.
After basic transesterification, the purification and adequate testing during processing is required to produce fuel grade esters.
Appropriate Technology
The selection of appropriate technology for production of biodiesel requires careful selection of processing steps, catalyst and downstream process integration. The quality of feed vegetable oil particularly FFA content plays and important role in identifying the suitable technology.
IIP Processes for Biodiesel
India Institute of Petroleum has developed three processes for biodiesel from non-edible oils and under exploited oils including Jatropha curcas, Pongamia, Salvadora, Madhuca Indica and Mixed Oils.