ULTRASONIC PRE-TREATMENTS OF WOOD CHIPS USED IN A CONVENTIONAL PYROLYSIS AND THEIR EFFECT ON BIOOIL COMPOSITION AND CALORIMETRY

摘要

As the traditional pulp and paper market is steadily declining, new uses of wood volume arernneeded. Conjugated with research to reduce human dependence to fossil fuel, bio-oil productionrnfrom wood biomass pyrolysis has emerged as an adequate solution to both problematics. However,rnpyrolysis efficiency needs improving. Ultrasounds have been successfully used in readings tornenhance biomass hydrolysis, benzene and toluene ring cleavage and extraction efficiency. Anrnultrasonic pre-treatment of the biomass could easily ease the internal chemical bond in the variousrncomponents of the wood (lignin, hemicellulose, cellulose) and consequently, have an effect on therncomposition of the bio-oils. In our research, various ultrasonic condition combinations (power,rnfrequency, exposition time) were applied on different wood chip sizes before a lab scale pyrolysisrn(500℃) was undergone. The content of the bio-oils were analysed by gas chromatography (GCFID)rninto 5 different families (light, acid, alcohol, ketone and phenol) and by classical calorimetry.rnResults have shown that the ultrasounds have slightly modified the bio-oil composition andrncalorimetry. As time increases, the phenol and ketone fraction increases and the light fractionrndecreases. As this situation is detrimental to the calorimetry, a compromise needs to be found.