Study on chemical oxidation of heat treated lignocellulosic biomass under oxygen exposure by STA-DSC-FTIR analysis

Published Date
Thermochimica Acta
20 November 2016, Vol.644:33–42, doi:10.1016/j.tca.2016.10.008

• Author 

• K. Candelier ^a,,
• J. Dibdiakova ^b
• G. Volle ^a
• P. Rousset ^a,c

• aCIRAD, UPR BioWooEB, F-34398 Montpellier, France
• bNIBIO, P.O. Box 115, NO-1431 Ås, Norway
• cJGSEE- KMUTT, Centre of Excellence on Energy Technology and Environment, Bangkok, Thailand

Received 9 September 2016. Revised 18 October 2016. Accepted 19 October 2016. Available online 19 October 2016.

Highlights

• •
  A new DSC-FTIR analysis is proposed to study wood thermal degradation and oxidation.
• •
  Chemical composition of raw material affects oxidation reactions of the pyrolyzed material.
• •
  Hardwoods are more sensitives to thermal degradation than softwoods.
• •
  Softwoods seem to be less oxidized than hardwoods treated in the same conditions.
• •
  FT-IR analysis confirms the heated treated wood oxidation reaction.

Abstract

Heat treatment helps enhance some properties of raw biomass by improving its decay resistance, its dimensional stability, increasing energy density and reducing transport costs of biomass. During storage period, many industrial sites undergo fires caused by self-ignition of torrefied or carbonized biomass. The main objective of this work was to study the chemical behavior of heat treated wood under oxygen exposure. Softwood and hardwood species have been thermally treated under a nitrogen atmosphere at different treatment conditions intensities. Sample mass and heat flow have been measured during the process to observe the temperature, time and air flow influence on reaction mechanisms of heat treated wood. The oxidation process and heat flux have been evaluated in addition. Results showed that reaction heat flows used for the treatment were correlated with temperature and time of thermal degradation of both examined wood species, as well as wood mass loss, respectively. However, hardwood (beech) seems to be more sensitive to thermal degradation and oxidation than softwood (silver fir) species. In addition, differential scanning calorimetry exothermic peak and wood mass gain were observed during oxygen exposure. In fact, this phenomenon was more pronounced for degradation carried out at high temperatures and times and it tends to be correlated with the elemental composition of wood. The main evolved products of heat treated wood were identified as water (H₂O), carbon monoxide (CO) and carbon dioxide (CO₂).

Keywords

Hardwoods

Heat flow

Mass loss

Oxidation

Softwoods

Thermal degradation

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• ⁎ 
  Corresponding author.

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