Wood milling is an intensively energy consuming operation that has a significant effect on energy yield of ethanol production processes as particle size is an important factor in productivity of saccharification methods. Fiber particle size was optimized for a very wide range of treatment conditions (temperature, agitation, and solid loads) for acid hydrolysis in a batch reactor. Also, heat and mass transfer effects were analysed by calculating the Thiele and Prater modulus at experimental conditions. Multivariate optimization results show that using a length-weighted fiber mean diameter (DL21) of 1.21-2.68 mm, a better sugar yield, concentration and lower furan production can be achieved. Agitation allowed a simultaneous particle size reduction and hydrolysis of polysaccharides. Heat and mass transfer studies suggest that acid diffusion is only important for hemicellulose hydrolysis at very high temperature and that particles are nearly isothermal. These results show that about 30% of the required energy for milling can be saved by using optimal particle size.
Available at: http://works.bepress.com/rafael_maya_yescas/61/