Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species
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...
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doaj-5dd421a49c994de1a39e30b3536e45422020-11-24T21:03:05ZengMDPI AGEnergies1996-10732018-01-0111120510.3390/en11010205en11010205Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic SpeciesDongdong Feng0Yijun Zhao1Yu Zhang2Shaozeng Sun3Jianmin Gao4School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaThe 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.http://www.mdpi.com/1996-1073/11/1/205biocharsteamgasificationchemical speciationAAEMs |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Dongdong Feng Yijun Zhao Yu Zhang Shaozeng Sun Jianmin Gao |
spellingShingle |
Dongdong Feng Yijun Zhao Yu Zhang Shaozeng Sun Jianmin Gao Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species Energies biochar steam gasification chemical speciation AAEMs |
author_facet |
Dongdong Feng Yijun Zhao Yu Zhang Shaozeng Sun Jianmin Gao |
author_sort |
Dongdong Feng |
title |
Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species |
title_short |
Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species |
title_full |
Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species |
title_fullStr |
Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species |
title_full_unstemmed |
Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species |
title_sort |
steam gasification of sawdust biochar influenced by chemical speciation of alkali and alkaline earth metallic species |
publisher |
MDPI AG |
series |
Energies |
issn |
1996-1073 |
publishDate |
2018-01-01 |
description |
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. |
topic |
biochar steam gasification chemical speciation AAEMs |
url |
http://www.mdpi.com/1996-1073/11/1/205 |
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