Energy Fuels 2010, 24, 250–252 Published on Web 10/14/2009
: DOI:10.1021/ef900535y
Supercritical Ethanolysis of Wheat Stalk Powder over CaO/Al2O3 and CaO/Al2O3/Fe3O4† Wen-Juan Xu,‡ Wei Zhao,*,‡ Chen Sheng,‡ Shi-Teng Zhong,‡ Xiao-Na Wu,‡ Cai-Hui Yan,‡ Sha Bai,‡ Zhi-Min Zong,‡ and Xian-Yong Wei*,‡,§ ‡
Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining and Technology, Xuzhou 221008, Jiangsu, China, and §Hubei Coal Conversion and New Carbon Material Key Laboratory, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China Received May 26, 2009. Revised Manuscript Received October 8, 2009
Limited reserves of fossil resources and severe pollutions, such as acid rain, photochemical smog, greenhouse effects, and ozone-layer depletion, from fossil fuel combustion along with the rapid increase in global energy consumption make the development of renewable energy technology more and more important. Biomass is the only practical source of renewable and clean liquid fuel.1 The advantages of cheapness, pollution-free,2,3 and abundance of biomass4,5 make biomass use very feasible. Rapid pyrolysis6-8 and high-pressure direct liquefaction (HPDL)9,10 are well-used methods for converting biomass into liquid fuel. More and more attention is being paid to HPDL because of the simplicity of the process and good quality of liquid products from the process. Both the solvent and catalyst are important for improving the yield and quality of the liquid products. Ethanol proved to be an effective solvent for HPDL of biomass, especially under supercritical conditions.11-13 Such a solvent can be produced from bioconversion of cereals, sugars, and lignocellulosic
materials.14 The commonly used catalysts include homoand heterogeneous species. Homogeneous catalysts can be uniformly distributed in the reaction system, but separation of the catalysts from liquid products is very difficult. Commonly used heterogeneous catalysts can be separated from liquid products but cannot be recovered from solid residue. Finding an active and recoverable catalyst should be an important subject for developing an efficient HPDL of biomass. Here, we report our preliminary results about noncatalytic and catalytic supercritical ethanolysis (SCE) of wheat stalk powder (WSP) using CaO/Al2O3 and CaO/Al2O3/Fe3O4 as catalysts. Wheat stalks were collected from the field in the vicinity of Xuzhou City, Jiangsu, China. WSP was prepared by washing the wheat stalks with water and then dried in sunlight, chopped into small pieces, and pulverized to pass through an 80 mesh sieve (
