PRODUCTION OF BIODIESEL USING HETEROGENEOUS CATALYST AND SUPER CRITICAL FLUID EXTRACTION

Abstract

Biodiesel is the only possible reciprocal to petro diesel and a boon to the fast depleting fossil fuel resources. Biofuel is produced from different feedstock including Algae, seeds of some terrestrial plants like Jatropha curcas, pongamia, castor, palm and oily wastes. The thesis addresses the multi-dimensional areas associated with the biodiesel production processes, covering the entire scope from seed based to non-terrestrial microalgae feedstock cultivation, extraction and its efficient conversion into liquid fuels. Design and development of efficient screw press expeller for oil expression from jatropha curcas seeds was the first investigation. This study is aimed to make efficient screw expeller to cater massive Jatropha biomass and its oil extraction. Experimental validation of the simulation is used to improve oil expeller for Jatropha seed by fabricating the expeller following the design and analysis by ANSYS FLUENT codes. An oil yield in excess of 98%, as compared to a maximum 75% for existing screw expellers, was achieved in practical runs which is very promising. An innovative airlift tubular photobioreactor was developed for growing algae in simulated conditions. Algal strain Chlorella sp was inoculated in photobioreactor which was sparged with air and carbon dioxide. The novel photobioreactor recorded a maximum experimental average yield of 0.65 g/L.day (13.3 g/m2.day) as compared to theoretical modeled yield of 0.82 g/L.day (14.26 g/m2.day), suggesting the device can be efficiently and cost-effectively employed in the production of algal biomass for biofuels. Supercritical Carbon dioxide (SC-CO2) fluid extraction (SCFE) was carried out to extract oil from Jatropha Curcas L. and microalgae (Chlorella Vulgaris) for biofuel production. The extraction was performed at temperature ranges of 40-80 oC and pressure of 4000-9000 psi in-order to investigate the optimum process parameters for Jatropha Curcas and microalgae biomass. The optimum yield for Jatropha was found to be 30.6 wt% and for microalgae it was 17.7 wt% (based on total oil contents present in the biomass) which was in close agreement with the time consuming traditional n-hexane based solvent extraction. The algal oil was then transesterified into biodiesel using nano-photo heterogeneous catalyst. The biodiesel produced using photosensitive catalyst was then characterized by using analytical techniques like GCMS and NMR and results are discussed. The physical properties of biodiesel are also analyzed according to ASTM standards.