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Abstract: Sweet sorghum is a high-yielding energy crop that leaves a large amount of lignocellulosic residues after the sugar fraction fermented to ethanol. Here, we developed a biphasic kinetic model for the dilute sulfuric acid-catalyzed hemicellulose hydrolysis of sweet sorghum bagasse at temperatures of 110–150°C, and we then calculated the kinetic parameters for xylose production and furfural decomposition. The results indicated that elevated reaction temperatures promote the hydrolysis of hemicellulose and the degradation of xylose. The xylose yield increased in proportion to reaction time in the initial stages and then declined due to the degradation of xylose to furfural. The pre-exponential factors for the ‘easy-to-hydrolyze’ fraction, the ‘hard-to-hydrolyze’ fraction of hemicellulose and xylose degradation were 3.53×106, 1.80×105 and 0.62min−1, respectively, and the activation energies were 60.7, 58.1 and 14.5kJ/mol, respectively. The ideal hydrolysis condition for xylose production was 140°C for 50min, under which the xylose yield reached 60% of hemicellulose weight. This xylose can be used to form bioethanol and produce further downstream products. [Copyright &y& Elsevier]

In industry, mass transfer limitation is a major and widespread problem in most of vegetable oil epoxidation reactors. To improve the quality of products and the efficiency of production, it is essential to understand the law of mass transfer in the epoxidation reaction system. In present work, epoxidation of fatty acid methyl esters with performic acid generated in situ was studied in a stirred vessel at 50–80 °C. At first, the Sauter mean diameter (D 32 ) was determined and correlated, the correlation can predict the D 32 evolution of the reaction. Then, individual experiments were performed to separately determine the intrinsic kinetic parameters and the mass transfer parameters. Finally, a macroscopic kinetic model was developed, which can well describe the effect of droplet size on the reaction. Noteworthy, the mass transfer limitation was significantly increased when reaction temperature rises to 80 °C. [ABSTRACT FROM AUTHOR]