An experimental and theoretical investigation of the thermal treatment of wood (Fagus sylvatica L.) in the range 200–260°C

Turner, Ian; Rousset, Patrick; Rémond, René; Perré, Patrick

doi:10.1016/j.ijheatmasstransfer.2009.10.020

Cited by 102 publications

(63 citation statements)

References 46 publications

(50 reference statements)

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“…It was previously suggested that better characterization of these products would help to identify whether second stage is either endothermic or exothermic; however, the under-prediction of particle temperature by the current model suggests the heat of reaction of the second stage is thermally neutral or even slightly exothermic. The sensitivity of the predicted temperature profile during this period to the mass loss kinetics and thermochemistry are agree with conclusions made from previous single-particle models [17]. Fourier's law, this heat generated in the inner layers can only conduct towards the outer layers of the particle when a negative temperature gradient exists ( < 0).…”

Section: Intraparticle Temperature Profilessupporting

confidence: 88%

“…Their assumed kinetic mechanism described wood thermal decomposition as a linear superposition of the decomposition hemicelluloses, cellulose, and lignin components. Turner noted that the reaction enthalpy term has a very important effect on the temperature profiles [17], however due to the lack of available parameters in the literature, the enthalpy of reaction of the hemicellulose decomposition was used as a tuning parameter.…”

Section: -D Computational Heat and Mass Transfer Model For The Torrementioning

confidence: 99%

“…One approach is to describe the wood/biomass as three independently reacting constituents (hemicelluloses, cellulose, and lignin) [17,21]. This approach is adopted when ease of application to different feedstocks is the goal.…”

Section: Solid Mass Loss Kineticsmentioning

confidence: 99%

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Modeling kinetics-transport interactions during biomass torrefaction: The effects of temperature, particle size, and moisture content

Bates

Ghoniem

2014

Fuel

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ABSTRACT:A comprehensive one-dimensional model accounting for the effects of heat and mass transfer, chemical kinetics, and drying was developed to describe the torrefaction of a single woody biomass particle. The thermochemical sub-models depend only on previously determined or measured characteristics, avoiding the use of fitting or tuning parameters and enabling a rigorous energy balance of the process. Moreover, a high temperature drying sub-model is introduced which overcomes the difficulties associated with existing approaches to give physically consistent results, smooth implementation, and numerical stability. The particle model was validated against experimental data from the literature for intraparticle temperature profiles, particle mass and energy yields over a range of particle sizes and reaction temperatures. The modeling results describe well the three distinct stages observed during the torrefaction of large particles including the heatup, drying, heat release due to exothermic reactions resulting in thermal overshoot, followed by thermal equilibrium where conversion is governed by mass loss kinetics. The nonlinear effects of particle size, temperature, moisture content, and residence time on the mass and energy yields are quantified and explained. Larger particles exhibit a significant internal temperature gradient and strong temperature overshoot especially at the centerline. The magnitude of the overshoot is a function of the conductivity, particle size, and average heat release rate. Because of the rise in the reaction rate, higher temperatures increase the sensitivity of the process to particle size. Due to the dependence of drying rate on heat transfer limitations, the sensitivity of torrefaction to initial moisture content increases strongly with particle size. Highlights: 1D coupled model describes the dynamics of drying and torrefaction of a single particle  Model predicts particle temperature overshoot, elemental, and energy balance  Validated against single particle experimental results from literature  Larger particles convert more non-uniformly with higher thermal overshoot.  Higher temperatures and increased moisture content exacerbate particle size effects

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Section: Intraparticle Temperature Profilessupporting

confidence: 88%

Section: -D Computational Heat and Mass Transfer Model For The Torrementioning

confidence: 99%

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Modeling kinetics-transport interactions during biomass torrefaction: The effects of temperature, particle size, and moisture content

Bates

Ghoniem

2014

Fuel

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“…The dimensional stability of wood becomes worse in wet conditions, which results in swelling of the wood and increases the risk for degradation by wood decay fungi. Thermal treatment, usually controls wood constituents without the use of oxygen (to avoid oxidation) and is carried out in the range 200 to 260 o C; this treatment gives the wood new physical, chemical, and mechanical properties (Turner et al 2010), and is an effective method to reduce hygroscopicity, improve dimensional stability, and resist fungal decay (González-Peña et al 2009;Šušteršic et al 2010). This treatment provides potential for the outdoor application of wood.…”

Section: Introductionmentioning

confidence: 99%

Thermal Treatment of Poplar Hemicelluloses at 180 to 220 °C under Nitrogen Atmosphere

Liang¹,

Wang²

2016

BioResources

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Hemicelluloses were separated from poplar wood and exposed to thermal treatment. Changes in chemical content were investigated from 180 °C to 220 °C in a nitrogen atmosphere. Fourier transform infrared spectroscopy, X-ray diffraction, and differential thermal gravimetric analysis were used to characterize the hemicellulose before and after the thermal treatment. The effects of temperature on hygroscopicity and color were measured. The results showed that hemicelluloses were sensitive to temperature. β-glucosidic bonds and side chains in hemicelluloses were cleaved around 180 °C, and the increased temperature promoted the breaking process. Esterification reactions happened during the treatment. When the treatment temperature reached 220 °C, all side chains broke down, and partial carbonization occurred. Therefore, the color became darker, and the hydrophobicity increased. This study could help to explain the changes in wood that occur during thermal treatment.

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“…During the decomposition of natural polymers present in the composition of wood char, resins, water and gases are formed (Drysdale 1998;turner et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Research on the Electrical Capacitance and Electrical Conductivity of Char Resulting From Natural and Treated Wood

Mačiulaitis

Jefimovas

Lipinskas³

2014

Journal of Civil Engineering and Management

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Abstract. Wood is a material widely used for construction purposes and having quite a number of advantages. However, one of the major drawbacks of wood are its flammability. in case of fire in wooden buildings or constructions made of timber structures, the most noticeable feature of combustion is charring these structures. this property is important for identifying the cause of a fire. therefore, it is necessary to relate charring timber structures with certain significant effects of fire such as its duration or temperature. it is also particularly important to identify whether timber has been treated with fire retardant solutions before the fire break-out. the values of electrical capacitance and conductivity for the media obtained from char resulting from natural wood and that treated with fire retardant solutions and dispersed in distilled water depending on heating time have been determined. Moreover, it has been stated that the electric conductivity of char resulting from natural wood is 100 times lower, and the electrical capacitance of such char is 1000 lower than those resulting from treated wood. the regression analysis of the obtained data has been performed. the empirical equations have been derived. the results of the conducted research have been summarised. priority has been given to the application of the method evaluating electrical conductivity.

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An experimental and theoretical investigation of the thermal treatment of wood (Fagus sylvatica L.) in the range 200–260°C

Cited by 102 publications

References 46 publications

Modeling kinetics-transport interactions during biomass torrefaction: The effects of temperature, particle size, and moisture content

Modeling kinetics-transport interactions during biomass torrefaction: The effects of temperature, particle size, and moisture content

Thermal Treatment of Poplar Hemicelluloses at 180 to 220 °C under Nitrogen Atmosphere

Research on the Electrical Capacitance and Electrical Conductivity of Char Resulting From Natural and Treated Wood

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