Abstract

The quality of biomass powders depends on the size reduction technology used to produce them. Attritional mills (e.g. hammer mills) require biomass that is chipped and pre-dried. These processes degrade the green chemical profile of biomass and complicate handling and storage. A multi-blade shaft mill (MBSM) produces fine powders in a single step from green biomass. This enhances utilisation in downstream biorefining processes. Investigations have evaluated the powder quality and the energy requirements of MBSM milling using pinewood at a range of moisture contents. The shape and size properties of powders were analysed using two-dimensional image analysis and surface features investigated by scanning electron microscopy. A higher fraction (55 to 80 %) of finer powders (< 0.5 mm) was observed through multi-blade milling in comparison to hammer milling (41 %). There were also significant differences in particle (MBSM powders produced from green logs) aspect ratios (0.54 to 0.58 vs. 0.36 to 0.43) and specific surface (33 to 56 mm-1 vs. 29 to 38 mm-1). The MBSM specific milling energy ranged from 99 to 232 kWh t−1 (dry mass (DM)). These results are promising for the conversion of biomass powders into value added products (e.g. bio-based chemicals and nanocellulose) and indicate that MBSM technology may have a niche application in biorefining.

Published in

Publisher: TAPPI

Conference

2021 PEERS Conference (21PEE04), 7 - 10 Novemeber, 2021, Atlanta, USA

Authors' information