Continuous production of biodiesel with supercritical methanol: Optimization of a scale-up plug flow

article i nfo A scale-up plug flow reactor was evaluated for the continuous production of biodiesel from refined palm kernel oil (PKO) with supercritical methanol and optimized by response surface methodology. The effects of the operating temperature (270-350 °C), pressure (15.0-20.0 MPa) and methanol:PKO molar ratio (20:1- 42:1) were evaluated at a constant residence time of 20±2 min by using a central composite design. Analysis of variance demonstrated that a modified quadratic regression model gave the best coefficient of determination (R 2 =0.9615) and adjusted coefficient of determination (Adj. R 2 =0.9273). The interaction terms in the regression model illustrated small synergistic effects of both temperature-pressure and temperature-methanol:PKO molar ratio. The optimal conditions were 325±5 °C, 18.0±0.5 MPa and a methanol:PKO molar ratio of 42±2:1, attaining a maximum production rate of 18.0±1.5 g biodiesel/min with a fatty acid methyl ester content of 93.7±2.1%. The product obtained from the optimal conditions had high cetane number, and could be considered as a fuel additive for cetane number enhancement.

[1]  Shiro Saka,et al.  Kinetics of hydrolysis and methyl esterification for biodiesel production in two-step supercritical methanol process , 2006 .

[2]  Dadan Kusdiana,et al.  Effects of water on biodiesel fuel production by supercritical methanol treatment. , 2004, Bioresource technology.

[3]  Jian-Zhong Yin,et al.  Biodiesel from soybean oil in supercritical methanol with co-solvent. , 2008 .

[4]  Ruengwit Sawangkeaw,et al.  Continuous Production of Biodiesel via Transesterification from Vegetable Oils in Supercritical Methanol , 2006 .

[5]  Phillip E. Savage,et al.  Assessment of Noncatalytic Biodiesel Synthesis Using Supercritical Reaction Conditions , 2008 .

[6]  G. Knothe.  Dependence of biodiesel fuel properties on the structure of fatty acid alkyl esters , 2005 .

[7]  Jian-Zhong Yin,et al.  Synthesis of biodiesel from soybean oil by coupling catalysis with subcritical methanol , 2008 .

[8]  J. M. Marchetti,et al.  Technoeconomic study of supercritical biodiesel production plant , 2008 .

[9]  Esteban A. Brignole,et al.  High pressure phase equilibria of supercritical alcohols with triglycerides, fatty esters and cosolvents , 2008 .

[10]  Jin-Suk Lee,et al.  Biodiesel production by heterogeneous catalysts and supercritical technologies. , 2010, Bioresource technology.

[11]  I. Abdulagatov,et al.  PVT measurements for pure methanol in the near-critical and supercritical regions , 2007 .

[12]  J. S. Hunter,et al.  Statistics for Experimenters: Design, Innovation, and Discovery , 2006 .

[13]  P. S. Mehta,et al.  Predicting the Density of Straight and Processed Vegetable Oils from Fatty Acid Composition , 2010 .

[14]  D. Skala,et al.  The problems in design and detailed analyses of energy consumption for biodiesel synthesis at supercritical conditions , 2009 .

[15]  van Jmn Han Kasteren,et al.  A process model to estimate the cost of industrial scale biodiesel production from waste cooking oil by supercritical transesterification , 2007 .

[16]  J. Quesada-Medina,et al.  Evidence of thermal decomposition of fatty acid methyl esters during the synthesis of biodiesel with supercritical methanol , 2011 .

[17]  Van P. Carey,et al.  The properties of gases & liquids: 4th Edition. Robert C. Reid, John M. Prausnitz, and Bruce E. Poling, McGraw-Hill Book Company, New York, NY, 1987, 741 pages, $49.50. , 1988 .

[18]  V. Gude,et al.  Transesterification of Camelina Sativa Oil using Supercritical and Subcritical Methanol with Cosolvents , 2010 .

[19]  Ruengwit Sawangkeaw,et al.  Effect of co-solvents on production of biodiesel via transesterification in supercritical methanol. , 2007 .

[20]  Ruengwit Sawangkeaw,et al.  A review of laboratory-scale research on lipid conversion to biodiesel with supercritical methanol (2001-2009) , 2010 .

[21]  Tao Wang,et al.  Continuous production of biodiesel fuel from vegetable oil using supercritical methanol process , 2007 .

[22]  Parisa A. Bahri,et al.  Supercritical methanol for fatty acid methyl ester production: A review , 2011 .

[23]  L. Clements,et al.  Viscosities of vegetable oils and fatty acids , 1992 .

[24]  M. Conradi,et al.  Are There Hydrogen Bonds in Supercritical Methanol and Ethanol , 1998 .

[25]  Juan C. Yori,et al.  Analysis of a Two-Step, Noncatalytic, Supercritical Biodiesel Production Process with Heat Recovery , 2007 .

[26]  Esteban A. Brignole,et al.  Phase Transitions in a Biodiesel Reactor Using Supercritical Methanol , 2007 .

[27]  Esteban A. Brignole,et al.  Density and Conversion in Biodiesel Production with Supercritical Methanol , 2010 .

[28]  T. Wu,et al.  Biodiesel production from Jatropha oil by catalytic and non-catalytic approaches: an overview. , 2011, Bioresource technology.