Steam explosion technology for the valorization of softwood bark

This thesis focuses on the valorization of softwood bark via a steam explosion processing step. A mixed softwood bark from an industrial source was steam exploded in a scalable system for continuous steam explosion. Two pathways for converting the steam-exploded bark into marketable products were investigated.The first path focused on sugars and bioethanol from the steam-exploded bark via enzymatic hydrolysis and fermentation. By studying enzymatic digestibility for substrates steam-exploded at a variety of conditions (autohydrolysis and dilute acid hydrolysis), it could be determined that conversion into glucose was modest (The second path focused on producing activated carbon from bark via steam explosion, activation, and pyrolysis. Results showed that carbon materials that had been steam exploded possessed more pronounced graphitic structure, higher surface area, and additional functionalities than materials that had not been steam exploded. Consequently, they also had a better capacity as adsorbents of the azo dye reactive orange 16.Finally, blow steam condensates were collected from the steam explosion stage, and the concentrations of some known degradation products were measured with high-performance liquid chromatography. With the help of Raman spectroscopy and modeling using orthogonal projections to latent structures, a solid model for quantification of furfural concentration was obtained, which opens the possibility of improved process monitoring and rapid quantification of this valuable byproduct.