The relationship between thermal diffusivity, energy of activation and temperature rise in subcritical self heating of fuels in simple geometries

Cocchi, Giovanni

doi:10.1016/j.fuel.2015.06.037

Cited by 11 publications

(3 citation statements)

References 13 publications

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“…However, the development of torrefaction raises safety issues. Indeed, combustible materials are liable to oxidation and are therefore prone to self-heating and self-ignition [7]. Moreover, the associated risks are boosted by production and handling scale up [8].…”

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confidence: 99%

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Reactor scale study of self-heating and self-ignition of torrefied wood in contact with oxygen

Evangelista

Arlabosse

Govin

et al. 2018

Fuel

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International audienceThis experimental work aims at investigating the potential development of self-heating when torrefied wood chips enter into contact with oxygen. Two kilograms of dried beech chips have been torrefied under nitrogen in a cylindrical reactor at 250 °C or 285 °C. The temperature was then leveled down between 100 °C and 160 °C and nitrogen flow was replaced by oxygen-containing flow. Influences of oxygen volumetric fraction and sweeping gas flow rate were investigated. Temperatures at different bed locations and gaseous product volumetric fractions at the bed output were monitored continuously. In some of the experiments a limited temperature rise was observed while in others a temperature runaway occurred. Thermal considerations indicate a clear enhancement of self-heating propensity with the severity of torrefaction. Gas phase analysis and molecule oxygen balance reveal an adsorption mechanism pathway and a higher rate of oxygen adsorption for the severely torrefied wood. Lowering the oxygen volumetric fraction or increasing the flow rate decrease self-heating behavior and was used to stop self-ignition of the bed

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confidence: 99%

“…However, coupling gas analysis and temperature monitoring during a self-heating might potentially help to obtain the heat of adsorption. This value can not be calculated separately from usual self-heating test methods [13] and is generally considered as a constant when modelling self-heating process [7]. , respectively.…”

mentioning

confidence: 99%

Reactor scale study of self-heating and self-ignition of torrefied wood in contact with oxygen

Evangelista

Arlabosse

Govin

et al. 2018

Fuel

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“…Self-heating is defined as a spontaneous phenomenon deriving from an unintended accumulation of heat within a reactive material. Several carbonaceous materials are affected by this situation involving mainly coal [9][10][11], lignocellulosic biomass [12,13] (hazelnut shells, olive pomace, wood [14][15][16][17]) and wastes (compost [18], sewage sludge [19]). Self-heating may occur as a consequence of chemical, physical or microbiological exothermic processes at low temperature.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of torrefied wood fixed bed: Thermal analysis and source term identification

Bouzarour

Pozzobon

Perré

et al. 2018

Fuel

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Dioxins and furans in biochars, hydrochars and torreficates produced by thermochemical conversion of biomass: a review

2023

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Converting raw biomass into valuable products protects the environment, improves economics, and helps tackle climate change by cutting resource demand and waste production. Thermochemical treatment is a common method for producing biochars, hydrochars and torreficates from biomass and organic wastes, which can also generate dioxins and furans and consequently limit the use of thermochemically converted chars. Here we review the presence of dioxins and furans in chars produced by hydrothermal carbonization, torrefaction, and pyrolysis processes under the influence of temperature, residence time, heating rate, pressure, and feedstock type. Dioxins and furans were mostly below 20 ng total toxic equivalence per kilogram (TEQ kg−1), with the highest level of 113 ng TEQ kg−1 found in over 100 samples of different char types. The most toxic products were hydrochars produced from sewage sludge. Processing temperature and feedstock type were key factors resulting in high dioxin levels in chars, and care should be taken when producing chars at temperatures up to 300 °C or using feedstocks previously contaminated with dioxins or preservatives.

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The relationship between thermal diffusivity, energy of activation and temperature rise in subcritical self heating of fuels in simple geometries

Cited by 11 publications

References 13 publications

Reactor scale study of self-heating and self-ignition of torrefied wood in contact with oxygen

Reactor scale study of self-heating and self-ignition of torrefied wood in contact with oxygen

Experimental study of torrefied wood fixed bed: Thermal analysis and source term identification

Dioxins and furans in biochars, hydrochars and torreficates produced by thermochemical conversion of biomass: a review

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