Ablative Pyrolysis of Wood Chips: Effect of Operating Conditions

We pyrolyzed entire wood chips (5 X 15 mm) in a new ablative reactor with the goal to evaluate the possibility to minimize grinding costs before pyrolysis. The effects of the operating parameters on the product yields and composition were investigated. Our results revealed that the bio-oil yield in the ablative reactor was favored at a moderate pyrolysis temperature of 500 8C, low initial thickness of the wood chips layer (<5 mm), low applied pressure on the wood chips (< 0.5 bar), and with the rotation of the bowl (>100 rpm). The temperature profile of the wood chips indicated that the ablative pyrolysis of thick layers is limited strongly by heat transfer rates. The maximum bio-oil yield obtained was approximately 60 wt%. The bio-oil elemental composition was determined mostly by its water content and that of char was affected primarily by the temperature. The knowledge of how operating conditions affect the ablative process can be used in the design of continuous mobile pyrolysis units in the future.