Industrial & Engineering Chemistry Research, Vol.54, No.16, 4581-4592, 2015
Mechanocatalytic Depolymerization of Lignocellulose Performed on Hectogram and Kilogram Scales
Mechanocatalytic depolymerization of lignocellulose constitutes a new frontier in biorefining. In a one-pot process, the combination of mechanical forces and acid catalysis leads to the full conversion of (dried) lignocellulose into water-soluble products (oligosaccharides and lignin fragments). In solution, these products undergo hydrolysis and other reactions, rendering high yields of monosaccharides along with precipitation of a sulfur-free lignin. Therefore, the water-soluble oligosaccharides may serve as a unique replacement for glucose and xylose for the production of platform chemicals. In this work, we report the results obtained from mechanocatalytic depolymerization of alpha-Cellulose, beechwood, and poplar wood performed in Simoloyer mills operating on hectogram and kilogram scales. Irrespective of the process scale, full conversion of the substrate into "water-soluble (ligno)celluloses", within milling durations of 1-3 h, is achieved. A phenomenological analysis of parameters for the process upscaling is provided. Moreover, the energy consumption of the process on different scales is assessed. Remarkably, energy consumption significantly decreases (from ca. 200 MWh.t(-1) to 9.6 MWh.t(-1)) with upscaling of the experiment from 1 g (planetary mill) to 1 kg. This increase in energy efficiency constitutes key evidence for the feasibility of the mechanocatalytic depolymerization on a large scale.