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Open AccessArticle

Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species

School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
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Energies 2018, 11(1), 205; https://doi.org/10.3390/en11010205
Received: 8 December 2017 / Revised: 6 January 2018 / Accepted: 8 January 2018 / Published: 15 January 2018
(This article belongs to the Special Issue Biomass Chars: Elaboration, Characterization and Applications Ⅱ)
The effect of chemical speciation (H2O/NH4Ac/HCl-soluble and insoluble) of alkali and alkaline earth metallic species on the steam gasification of sawdust biochar was investigated in a lab-scale, fixed-bed reactor, with the method of chemical fractionation analysis. The changes in biochar structures and the evolution of biochar reactivity are discussed, with a focus on the contributions of the chemical speciation of alkali and alkaline earth metallic species (AAEMs) on the steam gasification of biochar. The results indicate that H2O/NH4Ac/HCl-soluble AAEMs have a significant effect on biochar gasification rates. The release of K occurs mainly in the form of inorganic salts and hydrated ions, while that of Ca occurs mainly as organic ones. The sp3-rich or sp2-sp3 structures and different chemical-speciation AAEMs function together as the preferred active sites during steam gasification. H2O/HCl-soluble AAEMs could promote the transformation of biochar surface functional groups, from ether/alkene C-O-C to carboxylate COO in biochar, while they may both be improved by NH4Ac-soluble AAEMs. H2O-soluble AAEMs play a crucial catalytic role in biochar reactivity. The effect of NH4Ac-soluble AAEMs is mainly concentrated in the high-conversion stage (biochar conversion >30%), while that of HCl-soluble AAEMs is reflected in the whole activity-testing stage. View Full-Text
Keywords: biochar; steam; gasification; chemical speciation; AAEMs biochar; steam; gasification; chemical speciation; AAEMs
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MDPI and ACS Style

Feng, D.; Zhao, Y.; Zhang, Y.; Sun, S.; Gao, J. Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species. Energies 2018, 11, 205.

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