Autohydrolysis of Arundo donax L., a Kinetic Assessment

Abstract

Arundo donax L. was submitted to a process of isothermal autohydrolysis in the temperature range of 150-195°C, for periods between 0 and 15 h and a liquid/solid ratio ) 8 g g -1 , for the purpose of hydrolyzing the hemicelluloses to oligomers (compounds which are of interest to the food industry) and monomers. A conventional kinetic model was developed that explains the evolution over time of the hemicelluloses and hemicellulose degradation products. Kinetic modeling was also carried out using the severity factor approach and the kinetic parameters obtained in these two ways have been compared.

Autohydrolysis of Hemicelluloses from Sugarcane Bagasse During Hydrothermal Pretreatment: a Kinetic Assessment

“…In contrast to the sugars, the production of sugar derivative compounds (and also decomposition products) was facilitated with increasing temperature as shown by lowest value of E a for the third step. Similar behavior was also found for other sources of biomass and pretreatment processes, as reported elsewhere [19,28,32,34].…”

“…A comparison of rate constants for the conversion of hemicelluloses into oligomers indicated a similar magnitude to those reported for the conversion of xylan into xylooligomers (k 1 ) for hydrolysis of palm shell (0.07017 min −1 at 180°C) [32], and a higher magnitude than that exhibited by aspen wood (0.00717 min −1 at 160°C), sugar maple (0.00900 min −1 at 160°C) [18], and Arundo donax (0.02655 min −1 at 180°C) [19]. Recently, Vallejos et al [17] reported k 1 , k 2 , and k 3 values similar to those obtained in this work for autohydrolysis of hemicelluloses from sugarcane bagasse, but using the kinetic model proposed by Mittal et al [18] and a different scale and reaction conditions.…”

“…Morinelly et al [33] reported an activation energy of 97, 108, and 120 kJ/mol for aspen wood, balsam, and switchgrass, respectively, whereas the activation energy was 147 and 149 kJ/mol for xylan from beech and A. donax [19,32].…”

“…The use of a simple kinetic model should be suitable to explain the autohydrolysis process at the pilot or industrial scale [19]. In this context, this study presents an evaluation and validation of a simplified pseudo-first-order kinetic model that considers the sequential irreversible reactions of hemicelluloses into oligomers, sugars, and decomposition products during the hydrothermal pretreatment of sugarcane bagasse in a batch reactor.…”

Autocatalytic Fractionation of Wood Hemicelluloses: Modeling of Multistage Operation

“…Other studies dealing with wood autohydrolysis have been reported for Acacia dealbata (a hardwood with hemicelluloses mainly made up of xylan) [9] and Pinus pinaster (a softwood with hemicelluloses mainly made up of glucomannan and xylan) [10]. Additional kinetic studies of single-stage autohydrolysis have been reported for a number or non-wood materials, including corncobs [11], vine shoots [12], Arundo donax [13], barley husks [14], bamboo [15], Cytisus scoparius [16], rye straw [17], and almond shells [18].…”