Torrefaction Kinetics of Red Oak (Quercus rubra) in a Fluidized Reactor

Abstract

a Different kinetic models have been proposed to characterize torrefaction of biomass, demonstrating dependencies on the raw material, experimental system, reaction time, and temperature. Conventionally, stationary processes have been used for kinetics studies of the torrefaction process. In this research, the torrefaction of red oak (Quercus rubra) in a bench-scale fluidized reactor was studied with emphasis on determining the kinetic parameters and improving the final material energy density. Mass loss and ultimate, proximate, and gross calorific analyses were performed on the resulting torrefied material. The primary reaction variables were the temperature (230 °C, 270 °C, 300 °C, and 330 °C) and the residence time (10 min, 20 min, and 30 min). The effect of temperature on the mass loss and energy density was much more significant than that produced by the increase in residence time. For the conditions studied, a one-step kinetic model with a firstorder reaction proved adequate to describe the torrefaction of red oak in the fluidized reactor. The reaction rate constant (k) for the torrefaction reaction was found to be 0.212 min -1 at 300 °C. The activation energy and frequency factor were 11.9 kJ/mol and 2.57 min -1 , respectively.

Torrefaction of Solid Olive Mill Residue

“…Besides wood, torrefaction of several biomass types such as bamboo (Rousset et al 2011), wheat straw (Shang et al 2013), rice straw (Huang et al 2012), sewage sludge (Atienza-Martinez et al 2013), and red oak (Carrasco et al 2013) have been studied extensively. Torrefaction experiments with different biomass samples have shown that torrefaction provides solid hydrophobic fuel with reduced moisture content (Felfri et al 2005;Sadaka and Negi 2009), increased energy density (Prins et al 2006a;Yan et al 2009;Rousset et al 2011), and increased higher heating value (HHV) (Bridgeman et al 2008;Couhert et al 2009;Deng et al 2009;Yan et al 2009).…”

Torrefaction assessment and kinetics of deoiled karanja seed cake

“…, Carassco et al . was investigated for this study. The reaction mechanism was assumed to be a one‐step process, wherein the reactivity of hemicellulose was considered while the cellulose and lignin content of biomass was found to be least reactive in the given torrefaction range .…”

“…The present model was more successful for volatilization kinetics ( r 2 = 0.98) as than in comparison to that of charification ( r 2 = 0.91). The activation energy determined in this study is reported along with the studies performed by other researchers in Table , although the model, pathway, raw material, and experimental device employed were different . As an extension of work, we are currently developing the gasification technology of entrained flow gasifier with the torrefaction as a pretreatment step for the production of synthesis gas.…”

“…Considering the reaction complexities during the torrefaction, a simplified kinetic model very similar to that used by Bradbury et al [27], Koullas et al [13], Reina et al [28], Carassco et al [29,30] was investigated for this study. The reaction mechanism was assumed to be a one-step process, wherein the reactivity of hemicellulose was considered while the cellulose and lignin content of biomass was found to be least reactive in the given torrefaction range [19,20,22].…”

Oxytree Pruned Biomass Torrefaction: Process Kinetics

“…The value of k for Oxytree is challenging to compare with the literature because it depends to a large extent on the kinetic model used to determine it. For example, depending on the test method, the k value for 300 °C for oak wood was in the range from 31 × 10 −5 s −1 to 121 × 10 −5 s −1 [52]. Similarly, the activation energy is estimated for the whole torrefaction process [53,54].…”