Supercritical extraction of biomass as an effective pretreatment step for the char yield control in pyrolysis

Abstract

This work demonstrates that the coupling of supercritical carbon dioxide extraction with pyrolysis is an effective method for the removal of extractives from forestry residues and generation of solid char with different properties from the remaining solid wood fractions. Extraction of the needles and stumps shows greater yields of resin acids, terpenes, steroids and other derivatives than that of pinewood bark, cones and branches. The char yields of both non-treated and scCO(2) extracted wood fractions varied from approximately 17.5 to 38.5 wt. % on dry basis at fast heating rates. The catalytic effect of extractives is significant on the yields and morphology of solid chars in fast pyrolysis and less pronounced at slow heating rates. These results are promising as they show that both the composition and location of extractives inclusions in the interior of wood particle can affect the morphology of char samples. Moreover, the impact of alkali metals on the wood devolatilization appears to be less compared to the lignocellulosic composition in slow pyrolysis. These results demonstrate that supercritical carbon dioxide extraction can be integrated in biorefinery as a pretreatment step to control the properties of pyrolysis products by varying the heating rate. (C) 2021 The Author(s). Published by Elsevier Ltd.

Keywords

Supercritical extraction; Char yield; Scots pine; Heating rate; Fluidisation

Published in

Renewable Energy
2021, volume: 170, pages: 107-117
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

• Arshadi, Mehrdad

  • Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Renewable Bioenergy Research

Publication identifier

• DOI: https://doi.org/10.1016/j.renene.2021.01.116

Permanent link to this page (URI)

https://res.slu.se/id/publ/111388