SGRE  Vol.1 No.2 , August 2010
Separation of Biomass Pyrolysis Oil by Supercritical CO2 Extraction
Abstract: Supercritical CO2 extraction was employed to separate simulated and real bio-oils. Effects of extraction pressure, temperature and adsorbents on distribution coefficient (or enrichment coefficient) of five representative compounds were investigated using a simulated bio-oil, which was composed of acetic acid (AC), propanoic acid (PA), furfural (FR), acetylacetone (AA) and 2-methoxyphenol (MP). The distribution coefficients of AA, FR and MP between super-critical CO2 phase and liquid phase were bigger than 1.5, while those of AC and PA characteristic of relatively strong polarity were less than 1. Temperature and pressure also had impacts on the distribution coefficients of AA, FR and MP, especially remarkable for AA. The extraction of simulated bio-oil spiked on three adsorbents shows that adsorbents influence extraction efficiency and selectivity by changing intermolecular forces. High extraction pressure and relative low temperature are beneficial to reduce the water content in the extract. In addition, the feasibility of supercritical CO2 extraction of real bio-oil was examined. After extraction in the extraction fraction total ketones increased from 14.1% to 21.15~25.40%, phenols from 10.74% to 31.32~41.25%, and aldehydes from 1.92% to 3.95~8.46%, while the acids significantly dropped from 28.15% to 6.92~12.32%, and water from 35.90% to 6.64~4.90%. In view of extraction efficiency, the optimal extraction temperature was determined to be 55℃. Extraction efficiency of the real bio-oil increased with rising pressure. The maximal extraction efficiency of real bio-oil on water-free basis could reach to 88.6%. After scCO2 extraction, the calorific value and stability of the extract fraction evidently increased and the acidity slight decreased with nearly 100% volatility below 140℃, suggesting potentially applicable as substitute for engine fuel.
Cite this paper: nullJ. Wang, H. Cui, S. Wei, S. Zhuo, L. Wang, Z. Li and W. Yi, "Separation of Biomass Pyrolysis Oil by Supercritical CO2 Extraction," Smart Grid and Renewable Energy, Vol. 1 No. 2, 2010, pp. 98-107. doi: 10.4236/sgre.2010.12015.

[1]   M. Baratieri, P. Baggio, L. Fiori and M. Grigiante, “Biomass as an Energy Source: Thermodynamic Constraints on the Performance of the Conversion Process,” Bioresource Technology, Vol. 99, No. 15, 2008, pp. 7063-7073.

[2]   J. L. Zheng and W. M. Yi, N. N. Wang, “Bio-Oil Production From Cotton Stalk,” Energy Conversion and Management, Vol. 49, No. 6, 2008, pp. 1724-1730.

[3]   A. V. Bridgwater and G. V. C. Peacocke, “Fast Pyrolysis Processes for Biomass,” Renewable and Sustainable Energy Reviews, Vol. 4, No. 1, 2000, pp. 1-73.

[4]   C. David, O. Anja and S. Yrj?, “Power Generation Using Fast Pyrolysis Liquids from Biomass,” Renewable and Sustainable Energy Reviews, Vol. 11, No. 6, 2007, pp. 1056-1086.

[5]   A. V. Bridgwater, D. Meier and D. Radlein, “An Overview of Fast Pyrolysis of Biomass,” Organic Geochemistry, Vol. 30, No. 12, 1999, pp. 1479-1493.

[6]   M. Peter, “Energy Production from Biomass (Part 2): Conversion Technologies,” Bioresource Technology, Vol. 83, No. 1, 2002, pp. 47-54.

[7]   Q. Lu, W. Z. Li and X. F. Zhu, “Overview of Fuel Properties of Biomass Fast Pyrolysis Oils,” Energy Conversion and Management, Vol. 50, No. 5, 2009, pp. 1376- 1383.

[8]   T. A. Milne, F. Agblevor, M. Davis, et al., “A Review of Chemical Composition of Fast Pyrolysis Oils,” In: A. V. Bridgwater, Ed., Developments in Thermochemical Biomass Conversion, London, Blackie Academic & Professional, 1997, pp. 409-424.

[9]   V. A. Yakovlev, S. A. Khromova, O. V. Sherstyuk, et al., “Development of New Catalytic Systems for Upgraded Bio-Fuels Production from Bio-Crude-Oil and Biodiesel,” Catalysis Today, Vol. 144, No. 3-4, 2009, pp. 362-366.

[10]   Y. Xu, T. J. Wang, L. L. Ma, et al., “Upgrading of Liquid Fuel from the Vacuum Pyrolysis Of Biomass over the Mo–Ni/γ-Al2O3 Catalysts,” Biomass and Bioenergy, Vol. 33, No. 8, 2009, pp. 1030-1036.

[11]   L. Garcia, R. French, S. Czernik, et al., “Catalytic Steam Reforming of Bio-Oils for the Production of Hydrogen: Effects of Catalyst Composition,” Applied Catalysis A: General, Vol. 201, No. 2, 2000, pp. 225-239.

[12]   I. Michio, S. Maria and H. Ed, “Emulsification of Pyrolysis Derived Bio-Oil in Diesel Fuel,” Biomass and Bioenergy, 2003, Vol. 24, No. 3, pp. 221-232.

[13]   Y. Xu, J. Chang, Q. Zhang, et al., “Upgrading of Bio-Oil by Esterification over Solid Base Catalyst,” Petrochemical Technology, Vol. 35, No. 1, 2006, pp. 615-618.

[14]   F. Mahfud, H. Melia′n-Cabrera, I. R. Manurung and H. J. Heeres, “Upgrading of Flash Pyrolysis Oil by Reactive Distillation Using a High Boiling Alcohol and Acid,” Trans IChemE, Part B, Process Safety and Environmental Protection, Vol. 85, No. B5, 2007, pp. 466-472.

[15]   B. Tuya, M. Chaala, C. R. Garcia-Perez, et al., “Colloidal Properties of Bio-Oils Obtained by Vacuum Pyrolysis of Softwood Bar Characterization of Water-Soluble and Water-Insoluble Fraction,” Energy Fuels, Vol. 18, No. 3, 2004, pp. 704-712.

[16]   J. Peng, P. Chen, H. Lou and X. M. Zheng, “Catalytic Upgrading of Bio-Oil by HZSM-5 in Sub- and Super-Critical Ethanol,” Bioresource Technology, Vol. 100, No. 13, 2009, pp. 3415-3418.

[17]   H. H. A. Hussain, “Supercritical Hexane Extraction: a New Solvent System for Extracting Bio-Oil,” Division of Fuel Chemistry, Vol. 53, No. 2, 2008, pp. 862-864.

[18]   P. K. Rout, M. K. Naik, S. N. Naik, et al., “Supercritical CO2 Fractionation of Bio-oil Produced from Mixed Biomass of Wheat and Wood Sawdust,” Energy & Fuels, Vol. 23, No. 12, 2009, pp. 6181-6188.

[19]   H. Y. Cui, T. Wang, F. J. Wang, et al., “Kinetic Study on One-pot Synthesis of Dimethyl Carbonate in Supercritical CO2 Conditions,” Industrial & Engineering Chemistry Research, Vol. 43, No. 24, 2004, pp. 7732-7739.

[20]   H. Wang, R. H. Liu, C. M. Zhang and J. D. Luan, “An Experimental Study on Determination of the Water Content in Bio-Oil by Karl-Fischer Titration,” Renewable Energy, Vol. 3, No. 1, 2005, pp. 17-20.

[21]   C. M. Jiao and F. He, “Heating Value Determination of Liquid Product from Corn Stalk Pyrolysis,” Journal of Shandong University of Technology, Vol. 20, No. 2, 2006, pp. 11-13.

[22]   Y. K. Matsui, Y. S. Fukuda and T. K. Inoue, “Effect of Natural Organic Matter on Powdered Activated Carbon Adsorption of Trace Contaminants: Characteristics and Mechanism of Competitive Adsorption,” Water Research, Vol. 37, No. 18, 2003, pp. 4413-4424.

[23]   C. Pelekani and V. L. Snoeyink, “Competitive Adsorption between Atrazine and Methylene Blue on Activated Carbon: The Importance of Pore Size Distribution,” Carbon, Vol. 38, No. 10, 2000, pp. 1423-1436.