Fast Pyrolysis of Hemicelluloses into Short-Chain Acids: An Investigation on Concerted Mechanisms

Abstract

The nature of the main primary mechanisms involved in lignocellulosic fast pyrolysis is often assumed to be radical mechanisms. Here we demonstrate that thermal depolymerization of native hemicelluloses can undergo several primary and secondary concerted reactions leading to light oxygenates that can compete with radical mechanisms. To model these reactions at a microscopic level, we used high-level quantum calculations based on functional theory. In parallel, a set of experimental data was collected to confirm the main structural features of extracted and purified hemicelluloses and to describe chemical variations within fast pyrolysis products released from various hemicellulosic fractions at 823 K. In general, the barriers computed at 800 K for pericyclic reactions were found to be reasonably low competing with these of homolytic reactions. The critical role of hydrogen bonding and spatial arrangement on product distribution was clearly demonstrated, stabilizing effects depending greatly on temperature. We reported a useful data set of intrinsic kinetic parameters and a reaction network readily available to complete kinetic models for “primary” and “secondary” fast pyrolysis of hemicelluloses.

Publication DOI: https://doi.org/10.1021/acs.energyfuels.0c02901
Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
College of Engineering & Physical Sciences > Energy and Bioproducts Research Institute (EBRI)
Additional Information: This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Funding: Action H2020-MSCA-IF-2014, Pyrochem, Grant 656967, entitled “Biopolymers 13C Tracking during Fast Pyrolysis of Biomass - A 2-Level Mechanistic Investigation”.
Uncontrolled Keywords: Fuel Technology,Energy Engineering and Power Technology,General Chemical Engineering,Energy Engineering and Power Technology,Chemical Engineering(all),Fuel Technology
Full Text Link:
Related URLs: https://pubs.ac ... gyfuels.0c02901 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2020-11-19
Published Online Date: 2020-10-16
Accepted Date: 2020-09-24
Authors: Carrier, Marion
Fournet, René
Sirjean, Baptiste
Amsbury, Sam
Alfonso, Yoselin Benitez
Pontalier, Pierre-Yves
Bridgwater, Anthony (ORCID Profile 0000-0001-7362-6205)

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