Characterization of Chemically and Physically Activated Carbons from Lignocellulosic Ethanol Lignin-Rich Stream via Hydrothermal Carbonization and Slow Pyrolysis Pretreatment

Edoardo Miliotti, Luca Rosi, Lorenzo Bettucci, Giulia Lotti, Andrea Maria Rizzo and David Chiaramonti
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Edoardo Miliotti: Renewable Energy Consortium for Research and Demonstration—RE-CORD, Viale Kennedy 182, Scarperia, 50038 Florence, Italy
Luca Rosi: Renewable Energy Consortium for Research and Demonstration—RE-CORD, Viale Kennedy 182, Scarperia, 50038 Florence, Italy
Lorenzo Bettucci: Renewable Energy Consortium for Research and Demonstration—RE-CORD, Viale Kennedy 182, Scarperia, 50038 Florence, Italy
Giulia Lotti: Renewable Energy Consortium for Research and Demonstration—RE-CORD, Viale Kennedy 182, Scarperia, 50038 Florence, Italy
Andrea Maria Rizzo: Renewable Energy Consortium for Research and Demonstration—RE-CORD, Viale Kennedy 182, Scarperia, 50038 Florence, Italy
David Chiaramonti: Renewable Energy Consortium for Research and Demonstration—RE-CORD, Viale Kennedy 182, Scarperia, 50038 Florence, Italy

Energies, 2020, vol. 13, issue 16, 1-17

Abstract: The aim of the present work is to investigate the possibility of producing activated carbons from the residual lignin stream of lignocellulosic ethanol biorefineries, as this represents an optimal opportunity to exploit a residual and renewable material in the perspective of sustainable bioeconomy, increasing biorefinery incomes by producing value-added bioproducts in conjunction with biofuels. Activated carbons (ACs) were produced via chemical (KOH) and physical (CO 2 ) activation. Char samples were obtained by slow pyrolysis (SP) and hydrothermal carbonization (HTC). Several HTC experiments were carried out by varying residence time (0.5–3 h) and reaction temperature (200–270 °C), in order to evaluate their influence on the product yield and on the morphological characteristics of the hydrochar (specific surface area, total pore volume and pore size distribution). ACs from hydrochars were compared with those obtained from pyrochar (via physical activation) and from the raw lignin-rich stream (via chemical activation). In both cases, by increasing the HTC temperature, the specific surface of the resulting activated carbons decreased from 630 to 77 m 2 g −1 for physical activation and from 675 to 81 m 2 g −1 for chemical activation, indicating that an increase in the severity of the hydrothermal pretreatment is deleterious for the activated carbons quality. In addition, the HTC aqueous samples were analyzed, with GC-MS and GC-FID. The results suggest that at low temperatures the reaction mechanisms are dominated by hydrolysis, instead when the temperature is increased to 270 °C, a more complex network of reactions takes place among which decarboxylation.

Keywords: hydrothermal carbonization; slow pyrolysis; lignin; activated carbon (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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