Revealing pyrolysis chemistry for biofuels production: Conversion of cellulose to furans and small oxygenates

Abstract

Biomass pyrolysis utilizes high temperatures to produce an economically renewable intermediate (pyrolysis oil) that can be integrated with the existing petroleum infrastructure to produce biofuels. The initial chemical reactions in pyrolysis convert solid biopolymers, such as cellulose (up to 60% of biomass), to a short-lived (less than 0.1 s) liquid phase, which subsequently reacts to produce volatile products. In this work, we develop a novel thin-film pyrolysis technique to overcome typical experimental limitations in biopolymer pyrolysis and identify a-cyclodextrin as an appropriate smallmolecule surrogate of cellulose. Ab initio molecular dynamics simulations are performed with this surrogate to reveal the long-debated pathways of cellulose pyrolysis and indicate homolytic cleavage of glycosidic linkages and furan formation directly from cellulose without any small-molecule (e.g., glucose) intermediates. Our strategy combines novel experiments and first-principles simulations to allow detailed chemical mechanisms to be constructed for biomass pyrolysis and enable the optimization of next-generation biorefineries.

Catalytic Pyrolysis of Pine Over HZSM-5 with Different Binders

“…Multi-ring aromatics have been postulated to be formed via reactions involving monocyclic aromatics and oxygenate fragments [42]. Furans and light oxygenate formation from cellulose derivatives are competing reactions [51]. The high formation of furans may limit the availability of small oxygenates for ring growth reactions.…”

Value-added organonitrogen chemicals evolution from the pyrolysis of chitin and chitosan

“…chitosan, are widely applied in the fields of agriculture, environmental protection, functional food, biomedical and biotechnology engineering, and textile industry, especially prepared as hydrogels and drug delivery materials (Baran, Aç ıksöz, & Menteş , 2016Baran, Inanan, & Menteş , 2016Kumar, 2010;Kumar, Muzzarelli, Muzzarelli, Sashiwa, & Domd, 2004). Recently, in order to reduce the dependence on fossil resources, various biomass (including cellulose, hemicellulose, and lignin) were converted into value-added bio-chemicals, such as furan compounds (Mettler et al, 2012;Wang, Ren, Li, Deng, & Sun, 2015) and phenol compounds (Hu, Shen, Xiao, Wu, & Zhang, 2013;Singh & Ekhe, 2014). However, less attention has been paid on the conversion and utilization of chitin and chitosan.…”

Cellulose, xylan and lignin interactions during pyrolysis of lignocellulosic biomass

“…A significant observation during biomass pyrolysis is the levoglucosan deficit phenomenon compared with pure cellulose. For lignocellulosic biomass, such as olive husk, hazelnut shell, spruce wood and beech wood, less than 3% levoglucosan in the liquid fraction of pyrolysis products was found, even though the spruce wood and beech wood tested contained more than 50% cellulose, which can produce up to 48% levoglucosan [17,18]. The interaction among cellulose, xylan and lignin may have suppressed the evolution of levoglucosan and significantly increased the evolution rate of 5-methylfurfural [19].…”