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Biodiesel Synthesis (biodiesel + synthesis)
Selected AbstractsLipase-catalyzed ethanolysis of soybean oil in a solvent-free system using central composite design and response surface methodologyJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2008Rafael Costa Rodrigues Abstract BACKGROUND: In this work we describe the synthesis of ethyl esters, commonly known as biodiesel, using refined soybean oil and ethanol in a solvent-free system catalyzed by lipase from Thermomyces lanuginosus. Central composite design and response surface methodology (RSM) were employed to optimize the biodiesel synthesis parameters, which were: reaction time, temperature, substrate molar ratio, enzyme content, and added water, measured as percentage of yield conversion. RESULTS: The optimal conditions obtained were: temperature, 31.5 °C; reaction time, 7 h; substrate molar ratio, 7.5:1 ethanol:soybean oil; enzyme content, 15% (g enzyme g,1 oil); added water, 4% (g water g,1 oil). The experimental yield conversion obtained under these conditions was 96%, which is very close to the maximum predicted value of 94.4%. The reaction time-course at the optimal values indicated that 5 h was necessary to obtain high yield conversions. CONCLUSION: A high yield conversion was obtained under the optimized conditions, with relative low enzyme content and short time. Comparison of predicted and experimental values showed good correspondence, implying that the empirical model derived from RSM can be used to adequately describe the relationship between the reaction parameters and the response (yield conversion) in lipase-catalyzed biodiesel synthesis. Copyright © 2008 Society of Chemical Industry [source] Preparation of Mg-Al hydrotalcite by urea method and its catalytic activity for transesterificationAICHE JOURNAL, Issue 5 2009Hong-Yan Zeng Abstract Layered double hydroxides based on the structure (Mg6Al2(OH)16CO3·4H2O) were synthesized by urea hydrolysis method and characterized by XRD, FTIR, SEM, and EDS. The results revealed that pH played a crucial role in the Mg-Al hydrotalcite precipitation by controlling [urea]/[NO] molar ratio in reaction solution at 378 K and the optimized [urea]/[NO] molar ratio was 4.0. The sample calcined at 773 K was used as a solid catalyst for biodiesel synthesis. The catalyst was found to have a high catalytic activity in transesterification of rape oil to methanol with about 94% oil conversion at 338 K for 3 h. The water content of the oil could be kept below 2.0 wt % and free fatty acid content of the oil could be kept below 3.0 mg KOH·g[oil],1 in order to get the best conversion. So, the solid catalyst was more tolerant to free fatty acid and water in rape oil than homogeneous basic-catalysts. Moreover, the catalyst could be reused, but catalytic activity decreased on reuse of the catalyst although it remained highly active for the five uses. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] A heterogeneous acid-catalyzed process for biodiesel production from enzyme hydrolyzed fatty acidsAICHE JOURNAL, Issue 1 2008Chia-Hung Su Abstract In this work, biodiesel synthesis via fatty acids esterification with methanol is conducted by using a heterogeneous catalyst made from cation-exchange resin. The kinetics of esterification is studied at the different levels of catalyst loading (3.65,53.6%, w/w), reaction temperature (333,353 K) and molar ratio of methanol to fatty acids (1:1 to 20:1). The reaction rate and fatty acids conversion increased with increases in catalyst loading, reaction temperature and molar ratio of feeding reactants. A pseudo-homogeneous kinetic model coupling the effect of catalyst loading, reaction temperature and methanol/fatty acids molar ratio used for describing the process gave a correlation coefficient of 0.95 between experimental and predicted data. The proposed model was further used to predict the optimal operating condition for obtaining equilibrium conversion of 0.99. A reaction temperature of 372.15 K, molar ratio of feeding reactants of 14.9:1 and reaction time of 9.5 h was numerically calculated as the optimal operating condition. Under this optimal operating condition, an experimental verification was carried out and a satisfactory match was observed between experimental data and model prediction. © 2007 American Institute of Chemical Engineers AIChE J, 2008 [source] Strategies to enhance cell growth and achieve high-level oil production of a Chlorella vulgaris isolateBIOTECHNOLOGY PROGRESS, Issue 3 2010Chun-Yen Chen Abstract The autotrophic growth of an oil-rich indigenous microalgal isolate, identified as Chlorella vulgaris CC, was promoted by using engineering strategies to obtain the microalgal oil for biodiesel synthesis. Illumination with a light/dark cycle of 14/10 (i.e., 14 h light-on and 10 h light-off) resulted in a high overall oil production rate (voil) of 9.78 mg/L/day and a high electricity conversion efficiency (Ec) of 23.7 mg cell/kw h. When using a NaHCO3 concentration of 1,500 mg/L as carbon source, the voil and Ec were maximal at 100 mg/L/day and 128 mg/kw h, respectively. A Monod type model was used to describe the microalgal growth kinetics with an estimated maximum specific growth rate (,max) of 0.605 day,1 and a half saturation coefficient (Ks) of 124.9 mg/L. An optimal nitrogen source (KNO3) concentration of 625 mg/L could further enhance the microalgal biomass and oil production, leading to a nearly 6.19 fold increase in voil value. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | ||||||||||