Deoxygenation-enhanced chemical looping gasification: a new pathway to produce hydrogen from biomass†

Zhao Sun, Hanpeng Liu, Sam Toan, Weizhi Shi, Dongfang Cheng, Zhiqiang Sun

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2 Scopus citations

Abstract

Biomass to hydrogen production has been regarded as a potential approach for green hydrogen synthesis. However, carbon dioxide and bio-tar are inevitably produced, which critically restricts the refinement of biomass-derived syngas. In this study, deoxygenation-enhanced chemical looping biomass gasification (DE-CLBG) is proposed for hydrogen-rich syngas production together with CO2/H2O deoxygenation and catalytic bio-tar removal using the composite Fe/CaO as the deoxidizer. The DE-CLBG process is comprised of a deoxygenated gasification stage and a regeneration stage. During the deoxygenated gasification stage, the deoxidizer is converted under steam gasification via CaO + Fe + O2− → Ca2Fe2O5 with biochar generation; at the regeneration stage, biochar is further gasified with the achievement of deoxidizer reduction via Ca2Fe2O5 + C → CaO + Fe + COx. Experimental results show that the hydrogen production and maximum concentration upon applying 0.300 g of deoxidizer per g of biomass are 6.70 mmol and 89.61 vol%, which was increased by 287% and 27%, respectively, compared with the non-deoxygenated process. Results from the Mössbauer spectrum show that Fe0 is finally transformed into Fe3+ in the form of Ca2Fe2O5 and a small amount of Fe3O4, corresponding to the deoxygenation efficiency of 99.21%. The NMR results imply that aromatic carbon is the main form in biochar whether introducing deoxidizer or not, and deoxygenation can promote the removal of O-alkyl C.

Original languageEnglish (US)
Pages (from-to)2613-2623
Number of pages11
JournalGreen Chemistry
Volume24
Issue number6
DOIs
StatePublished - Feb 25 2022

Bibliographical note

Funding Information:
This work was supported by the National Natural Science Foundation of China (52106193 and 51876224), the Natural Science Foundation of Hunan Province (2021JJ40756), the Science and Technology Innovation Program of Hunan Province (2020GK2070 and 2021RC4006), and the Innovation-Driven Project of Central South University (2020CX008).

Publisher Copyright:
This journal is © The Royal Society of Chemistry

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