Steam explosion of straw in batch and continuous systems

Abstract

The effects of the steam-explosion treatment on aqueous fractionation and bioconversion of wheat straw have been investigated. The treatments have been carried out in batch and continuous reactors with capacity of 0.5 Kg/cycle and 150 Kg/h, respectively. The exploded materials have been sequentially extracted with water at 65°C and sodium hydroxide 1.5%. Analytical determinations of liquid fractions and solid residues have led to the fractionation pattern of the carbohydrates as monomers, oligomers, and polymers. Evaluations of total acidity, ash content, and lignin recovery have improved understanding of the process. This part of the work has allowed us to derive: the empiric relationship between the batch and the continuous reactors and the yield and availability of pentoses and hexoses in various phases. Selected samples have been tested in enzymatic-hydrolysis experiments, pointing out the effect of treatment severity and reactor used on the saccharification yield.