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Characterization of lignin thermal processing in a biorefinery perspective

Abstract : The thermo-chemical conversion of lignin is an important aspect of lignocellulosic biorefinery in order to produce carbon fibers, polymer additives, green aromatics or biofuels. Protobind 1000 lignin was characterized by thermogravimetry, calorimetry, in-situ rheology, in-situ 1H NMR, solution state 13C and 31P NMR. A multiple techniques including elemental analysis, GPC-UV, FTIR, solid-state NMR and LDI-FTICRMS, were performed to understand the softening and pyrolysis of lignin. An overall physical and chemical mechanism of thermo-chemical conversion of lignin has been proposed. A twin screw extrusion of lignin was carried out using Process 11, following the in-situ high temperature rheology and rheomix internal mixing. The operating window was derived from torque evolution at varying throughputs of 0.1-0.3kg.h-1 and rotation speed of 300-600 rpm at barrel temperature of 150°C for two screw configurations. The lignin extrudates obtained at key extrusion conditions were characterized by FTIR, GPC-UV/ELSD, solution state 1H-13C HSQC NMR. The analysis of lignin melts shows no major structural changes concluding twin screw extruder as a hot melt feeder. The lignin characterization in a liquid media i.e. H2O, ethanol and aq. NaOH, were studied by wet rheology, DLS, zeta potential measurement, SAXS and real-time visual analysis. The lignin liquefaction was carried out in ethanol and the liquefaction products were analysed by UV resonance Raman spectroscopy, GPC-UV and UV-Visible absorption and fluorescence spectroscopy. The structural changes undergone by lignin during liquefaction was accounted.
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Theses
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http://docnum.univ-lorraine.fr/prive/DDOC_T_2016_0007_SHRESTHA.pdf
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https://hal.univ-lorraine.fr/tel-02526450
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Submitted on : Tuesday, March 31, 2020 - 3:51:57 PM
Last modification on : Friday, February 26, 2021 - 3:32:07 PM

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  • HAL Id : tel-02526450, version 1

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Binod Shrestha. Characterization of lignin thermal processing in a biorefinery perspective. Chemical and Process Engineering. Université de Lorraine, 2016. English. ⟨NNT : 2016LORR0007⟩. ⟨tel-02526450⟩

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