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Main Title: Towards biochar and hydrochar engineering
Subtitle: influence of process conditions on surface physical and chemical properties, thermal stability, nutrient availability, toxicity and wettability
Author(s): Dieguez-Alonso, Alba
Funke, Axel
Anca-Couce, Andrés
Rombolà, Alessandro Girolamo
Ojeda, Gerardo
Bachmann, Jörg
Behrendt, Frank
Type: Article
Language Code: en
Abstract: The impact of conversion process parameters in pyrolysis (maximum temperature, inert gas flow rate) and hydrothermal carbonization (maximum temperature, residence time and post-washing) on biochar and hydrochar properties is investigated. Pine wood (PW) and corn digestate (CD), with low and high inorganic species content respectively, are used as feedstock. CD biochars show lower H/C ratios, thermal recalcitrance and total specific surface area than PW biochars, but higher mesoporosity. CD and PW biochars present higher naphthalene and phenanthrene contents, respectively, which may indicate different reaction pathways. High temperatures (>500 °C) lead to lower PAH (polycyclic aromatic hydrocarbons) content (<12 mg/kg) and higher specific surface area. With increasing process severity the biochars carbon content is also enhanced, as well as the thermal stability. High inert gas flow rates increase the microporosity and wettability of biochars. In hydrochars the high inorganic content favor decarboxylation over dehydration reactions. Hydrochars show mainly mesoporosity, with a higher pore volume but generally lower specific surface area than biochars. Biochars present negligible availability of NO3- and NH4+ , irrespective of the nitrogen content of the feedstock. For hydrochars, a potential increase in availability of NO3- , NH4+ , PO4 3- , and K+ with respect to the feedstock is possible. The results from this work can be applied to “engineer” appropriate biochars with respect to soil demands and certification requirements.
Issue Date: 27-Feb-2018
Date Available: 5-Mar-2018
DDC Class: 629 Andere Fachrichtungen der Ingenieurwissenschaften
Subject(s): pyrolysis
hydrothermal carbonization
biochar engineering
Polycyclic Aromatic Hydrocarbon (PAH)
Sponsor/Funder: DFG, TH 662/19-1, Open Access Publizieren 2017 - 2018 / Technische Universität Berlin
Journal Title: Energies
Publisher: MDPI
Publisher Place: Basel
Volume: 11
Issue: 3
Publisher DOI: 10.3390/en11030496
Page Start: 1
Page End: 26
ISSN: 1996-1073
Appears in Collections:FG Energieverfahrenstechnik und Umwandlungstechniken regenerativer Energien » Publications

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