Le cyclone : un réacteur multifonctionnel : application à la pyrogazéification et à la pyroliquéfaction de la biomasse

Abstract : In fast pyrolysis conditions, biomass can be converted mainly into liquids (bio-oils) or into gases (high fractions of CO and H2 which are of energetical or chemical interest. The experiments reported in this work are performed in a laboratory-scaled set-up including a cyclone reactor heated at its walls and fed by a flowrate of wood sawdust. All the products of the reaction (char, liquids and gases) are collected and analysed. The mass and elementary (C, H, 0) balances closures are very accurate. Basically by changing the operating conditions, the products distribution is significantly varied : the reaction can be directed to pyro-liquefaction at low temperature (maximum yields of liquids : 75 %) or to pyro-gasification at high temperature (maximum yields of gases : 85 %). A maximum throughput close to 1 kg h-1 may be achieved in steady state in a 0.5 L reactor. At lower temperatures, the excess of char formed can be converted during steam gasification steps alterned with the pyrolysis sequences. A general modelling takes into account the scaling laws of the reactor (hydrodynamics and heat transfers) and a scheme for the consumption of the particules and for thermal cracking of vapours. It allows to predict the variations of the selectivities as a function of the operating conditions, in agreement with the experimental results, and for different sires of cyclones. Besides, secondary cracking reactions are proved to occur mainly in the heart of the reactor, but also partly inside a thin boundary layer close to the hot walls.
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Theses
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http://docnum.univ-lorraine.fr/prive/INPL_T_2003_BROUST_F.pdf
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https://hal.univ-lorraine.fr/tel-01750108
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Submitted on : Thursday, March 29, 2018 - 12:38:01 PM
Last modification on : Thursday, January 31, 2019 - 1:27:53 AM

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François Broust. Le cyclone : un réacteur multifonctionnel : application à la pyrogazéification et à la pyroliquéfaction de la biomasse. Alimentation et Nutrition. Institut National Polytechnique de Lorraine, 2003. Français. ⟨NNT : 2003INPL064N⟩. ⟨tel-01750108⟩

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