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Research article - Peer-reviewed, 2020

Towards negative carbon emissions: Carbon capture in bio-syngas from gasification by aqueous pentaethylenehexamine

Ma, Chunyan; Wang, Nan; Chen, Yifeng; Govind Khokarale, Santosh; Bui, Thai Q.; Weiland, Fredrik; Lestander, Torbjörn; Rudolfsson, Magnus; Mikkola, Jyri-Pekka; Ji, Xiaoyan


In this work, an aqueous pentaethylenehexamine (PEHA) solution was studied for CO2 removal from bio-syngas for the first time. Firstly, pure CO2 absorption in aqueous PEHA solution under different conditions was conducted, and 20 wt% PEHA solution was identified as the best option. Secondly, the capture of CO2 was tested with synthetic syngas from a gas cylinder, and the species other than CO2 showed a negligible impact on CO2 removal. Finally, to evaluate the practical feasibility of using aqueous PEHA solution on the downstream CO2 capture, the pilot experiments of gasification with boreal forest-based biomasses were designed to provide real syngas with a realistic distribution in composition for further testing. The results showed that the operating conditions and the type of feedstocks affected the distribution in the bio-syngas composition. Among these feedstocks, at the optimal oxygen supply, using spruce needles generated the highest yields of CO and H2 and, meanwhile, gave rise to similar yields of other gases such as CO2, CH4, etc. The influence of the species other than CO2 for CO2 removal was negligible. Additionally, aqueous PEHA solution was tested as a biomass pretreatment agent, showing that no significant changes could be identified by the ultimate analysis (except for increased nitrogen content), but the yields of CO were affected negatively. On the other hand, when using the pretreated biomass by the aqueous PEHA solution, the NH3 concentration in bio-syngas reached to the highest (4000 parts per million), which slightly affected the CO2 absorption capacity and initial absorption rate of 20 wt% PEHA solution in a positive way.


pentaethylenehexamine; CO2 removal; biomass pre-treatment; gasification; bio-syngas; negative carbon emission

Published in

Applied Energy
2020, volume: 279, article number: 115877

Authors' information

Ma, Chunyan
Luleå University of Technology
Wang, Nan
Luleå University of Technology
Chen, Yifeng
Luleå University of Technology
Govind Khokarale, Santosh
Umeå University
Bui, Thai Q.
Umeå University
Weiland, Fredrik
RISE Energy Technology Center
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology
Mikkola, Jyri-Pekka
Åbo Akademi University
Ji, Xiaoyan
Luleå University of Technology

Sustainable Development Goals

SDG7 Affordable and clean energy

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