Experimental and numerical analysis of wood thermodegradation Mass loss kinetics A. Pe ´trissans • R. Younsi • M. Chaouch • P. Ge ´rardin • M. Pe ´trissans Received: 30 May 2011 / Accepted: 14 July 2011 / Published online: 30 July 2011 Ó Akade ´miai Kiado ´, Budapest, Hungary 2011 Abstract Torrefaction is a thermal treatment step in a temperature range of 210–240 °C, which aims to improve the dimensional stability and durability of wood. The mass loss kinetics for torrefaction of wood samples was studied using equipment specially conceived to measure mass losses during thermal treatment. Laboratory experiments were performed under nitrogen for heating rates of 0.1, 0.25, 1, and 2 °C min -1 . A mathematical model for the kinetics of the thermodegradation process was used and validated. Measurements of temperature distribution and anhydrous mass loss were performed on dry sample of poplar wood during torrefaction in an inert atmosphere for different temperatures. The mathematical formulation describing the simultaneous heat and mass transfers requires coupled nonlinear partial differential equations. These unsteady-state mathematical model equations were solved numerically by the commercial package FEMLAB for the temperature under different treatment conditions. A detailed discussion of the computational model and the solution algorithm is given below. Once the validity of different assumptions of the model had been analyzed, the experimental results were compared with those calculated by the model. Acceptable agreement was achieved. Keywords Heat treatment  Modeling  Reaction kinetics  Thermodegradation  Wood Introduction Nowadays, the use of wood as building material is pro- moted. The heat treatment of the wood by mild pyrolysis is used to improve some of the characteristics of the final wood product, such as, its durability and dimensional sta- bility. This process substitutes the use of external chemical products, which enables the treated wood to remain as an environmentally friendly product. Its an effective method to improve biological durability of wood [1–3]. The heat treatment of the wood induces a chemical modification of the main wood constituents. The lignin polymer structure is modified [4–8], the ratio between the amorphous and the crystalline cellulose is also changed [9–11], hemicelluloses are strongly decomposed [10, 12, 13], and some precursor products of the charcoal appear [14]. These chemical modifications confer with the new wood properties, such as, the improved dimensional stability [15–17], the improved fungal resistance [18–20], some color changes [21–25], hydrophobic increase [19, 22, 25–29], and improved mechanical properties [30–32]. The concept of thermal treatment to stabilize the wood structure has lead to the development of several treatment processes in some European countries [1]. In the 70s, the research developed by the Ecole des Mines de Saint-E ´ ti- enne (France) has worked out for the first time, an indus- trial process named «Retified wood Ò ». More recently, in the 90s, the forest industry in Finland has developed a new process; Thermowood Ò . Some others technologies have been developed, such as, the Netherlands pro- cess «PLATO Ò » and the Menz Holz’s process OHT (Oil Heat Treatment) in Germany. The wood torrefaction is a heat treatment of ligno-cellulosic material carried out at temperatures up to 300 °C. Torrefaction can be carried out under different gaseous atmospheres. Gaseous combustion A. Pe ´trissans  M. Chaouch  P. Ge ´rardin  M. Pe ´trissans LERMAB Universite ´ Nancy I, BP 70239, 54506 Vandoeuvre les Nancy, France e-mail: anelie.petrissans@lermab.uhp-nancy.fr R. Younsi (&) De ´partement de Ge ´nie Me ´canique, E ´ cole Polytechnique de Montre ´al, Montreal, QC H3C 3A7, Canada e-mail: ramdane.younsi@polymtl.ca 123 J Therm Anal Calorim (2012) 109:907–914 DOI 10.1007/s10973-011-1805-1