HARVESTING OF ALGAE AND PRODUCTION OF UPGRADED OIL FROM ALGAL BIOMASS

Abstract

Algae are considered as 3rd generation bio fuel for bio-oil production, it has good potential for the bio-oil production as some of the algal species, mainly micro algal species have high growth rate with significantly high lipid content. Out of around 50,000 algal species only few algae have been exploited, Bio-oil produced from algal biomass basically contains fatty acids and has high value of viscosity, therefore are not suitable for direct use in combustion engines. Due to this reason up gradation of bio-oil is necessary. In the present work, growth of microalgae and production of biomass was done in lab by performing single parameter optimization process to enhance algal growth and lipid content for biomass processing and native algal biomass collected from Solani River in Roorkee (i.e. is mainly consisting of Hydrodictyon and Ulotrichalean strains of green algae) has been used. The algal biomass has been found to contain 14.47 % lipid content. Oil from the dried algal biomass (microalgae and macro algae) has been extracted using ultrasonic technique. Oil was then upgraded to bio-diesel using homogeneous catalyst (CH3ONa) to achieve high yield and standard of biodiesel and avoid saponification. Optimization and modeling of the algal oil extraction was done using Design Expert software version 9 trials. Box-Behnken model using 3 factors (solvent to biomass ratio, amplitude and reaction time) with 3 levels each was used to fix the experimental conditions. Various levels are solvent to biomass ratio (5, 6, 7), amplitude % (60, 70, 80) and reaction time (40, 50, 60 mints). Total 17 run were obtained to conduct experiments. The optimized conditions that were obtained by response surface methodology are: solvent to biomass ratio 6, amplitude % 70 and reaction time 50 mints. Further, the algal biomass before and after extraction was characterized by using CHNS analysis and FESEM (Field emission microscopy scanning electron) analysis. The biodiesel was characterized by FT-IR (Fourier transform-infra red spectroscopy) and GC-MS (Gas Chromatography- MassSpectroscopy) analysis. Model is suitable to predict the algal oil yield within the design space with error limit of ±1.5 % after that algal oil and algal biodiesel were analyzed by determining various properties such as viscosity, cloud and pour point, density etc. ,properties of bio-diesel matched as those prescribed in IS-15607:2005