In this article, various methods including soxhlet, Bligh & Dyer (B&D), and ultrasonic-assisted B&D were investigated for the extraction of lipid from algal species Chlorella vulgaris. Relative polarity/water content and impolar per polar ratios of solvents were considered to optimize the relative proportions of each triplicate agent by applying the response surface method (RSM). It was found that for soxhlet, hexane-methanol (54-46%, respectively) with total lipid extraction of 14.65% and chloroform-methanol (54-46%, respectively) with the extraction of 19.87% lipid were the best set of triplicate where further addition of acetone to the first group and ethanol to the second group did not contributed to further extraction. In B&D, however, chloroform-methanol-water (50%-35%-15%, respectively) reached the all-time maximum of 24%. Osmotic shock as well as ultrasonication contributed to 3.52% of further extraction, which is considered to promote the total yield up to almost 15%. From the growth data and fatty acid analysis, the applied method was assessed to be appropriate for biodiesel production with regard to selectivity and extraction yield.

To investigate the effect of reactor performance/confi guration of biodiesel production on process parameters (mass & energy consumption, required facilities etc.), two diverse production processes (from vegetable oil) were implemented/designed using Aspen HYSYS V7.2. Two series reactors were taken into account where overall conversion was set to be 97.7% and 70% in fi rst and second processes respectively. Comparative analysis showed that an increase in conversion yield caused to consumption reduction of oil, methanol, cold energy and hot energy up to 9.1%, 22%, 67.16% and 60.28% respectively; further, a number of facilities (e.g. boiler, heat exchanger, distillation tower) were reduced. To reduce mass & energy consumption, mass/heat integration method was employed. Applying integration method showed that in the fi rst design, methanol, cold and hot energy were decreased by 49.81%, 17.46% and 36.17% respectively; while in the second design, oil, methanol, cold and hot energy were decreased by 9%, 60.57% 19.62% and 36.58% respectively.

In this study, extraction of lipid from algal sp. Chlorella vulgaris is investigated based on Bligh and Dyer method employing methanol and chloroform on wet biomass. Optimization methodology was established on comparison of pretreatment methods as well as investigation of ultrasonication and stirrer parameters to enhance cell disruption. It was found that biomass with water/solid proportion (w/s = 5) operating temperature of 50°C both for ultrasonication and shaking, 5 min ultrasonication with further 3 h of stirring with 200 rpm is the best set of parameters for breakdown of cell envelops, and using these parameters, total extraction of 22.07% was obtained. Kinetic study of breakdown was carried out with further full-factorial investigation of extraction (%) vs time and temperature. Using Arrhenius equation, activation energy of about 34.73 kJ/mol was obtained for this algal sp. with R 2 = 97.81%. Further analysis using analysis of variance showed that when using lower temperatures, sudden increase of extraction occurs in longer times, and vice versa, hence emphasizing the interaction thereof. It was also found that temperature plays the vital role among all examined parameters.

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