Biomass Pyrolysis: A Review of the Literature Part 2—Lignocellulose Pyrolysis

Abstract

A normative review of the literature describing the products, mechanisms, and rates of lignin and whole biomass pyrolysis is presented. The role of a complex sequence of competing solid-and vapor-phase pyrolysis pathways is elucidated. 175 K. W. Böer et al. (eds.), Advances in Solar Energy © Plenum Press, New York 19854.3.2.1 Products. At low pressure, anhydrosugars distill when heated to temperatures above 200°C and can be quantitatively recovered. 94 -99 However,levoglucosenone is known to polymerize in the liquid phase even at low temperatures,lOO and many anhydrosugars undergo vapor phase dehydration reactions in the presence of acid catalysts. 95 . 97 ,lOl,l02 In addition to distillation,103,l04 monosaccharides also polymerize to high molecular weight glucans which undergo subsequent fragmentation reactions, resulting in the formation of a wide variety of furans, ketones, aldehydes, and acids. l05 ,l06 Heyns and his coworkers l05 ,l06 observed the same degradation products from sixteen mono-, di-, oligo-, and polysaccharides. This caused * In Part 1 of this Review, concern was expressed over the apparent use of a (mis)identity A2 -B2=? (A -B)2 by Lewin and Basch 61 . Lewin and Basch have independently checked their work and report that their analysis did not involve the use of the (mis)identity given above. 180 CHzOH ;:::= ,t°'-O

Aging of oily soils on textiles. Chemical changes upon oxidation and interaction with textile fibers

“…Thermal degradation of cellulose is known to involve a free radical mechanism (18)(19)(20). A number of investigators have used electron paramagnetic resonance spectroscopy to study formation of free radicals in cellulose heated to low temperatures.…”

Pyrolysis of wheat straw-derived organosolv lignin

“…via pyrolysis (thermal degradation of organic matter in absence of air). The literature on the pyrolysis of lignin for the production of chemicals typically reports yields of mono-phenolic compounds that rarely exceed 5-6%, based on lignin [10][11][12]. Economic and technological considerations still preclude a large-scale mass production of low molecular weight chemicals from lignin in competition with petrochemicals.…”

Compensation Effects In The Non-isothermal Pyrolysis Of Wood

“…In terms of the study of wood pyrolysis as a solid-state kinetics, this compensating behaviour purported the simultaneous pyrolysis of a considerable number of components within wood [9,10]. It supported the view that within cellulose, two parallel competing reactions occurred for the primary degradation process [11,12], with the subsequent consecutive reactions occurring that accounted for the products first formed decomposing or reacting to form a new set of final products [13].…”