(2016) Energy Conversion and Management_Use of carbon dioxide as a reaction medium in the thermo-chemical process for the enhanced generation of syngas and tuning adsorption ability of biochar

Cho D.-W., Kwon E.E., Song H.

(Elsevier Ltd) Energy Conversion and Management ISSN: 1968904 Vol.117 Issue. Article No. DOI: 10.1016/j.enconman.2016.03.027

This study mechanistically investigated the influences of CO₂ on syngas (H₂ and CO) production during thermo-chemical conversion of red seaweed, and further explored the possible utility of the produced biochar as a medium for adsorption of inorganic/organic contaminants in aqueous phase. In order to elucidate the key roles of CO₂ in the thermo-chemical process, the composition analysis of syngas and the qualitative analysis of pyrolytic oil were conducted and compared with those in pyrolysis in N₂ condition. Pyrolysis of red seaweed in the presence of CO₂ led to the enhanced generation of syngas at the entire experimental temperatures. For example, the ratio of CO to H₂ in the presence of CO₂ at 620°C was enhanced by ∼400%, as compared to the case in N₂. This enhanced generation of syngas resulted in significant pyrolytic oil reduction by ∼70% at 620°C via the unknown reactions between VOCs and CO₂. In addition, biochar generated in the CO₂ environment exhibited comparatively higher surface area (61 m² g^-1) and more porous structure. The morphological modification induced by CO₂ provided the favorable condition for removal of methylene blue from the aqueous phase. Thus, this study experimentally demonstrated that exploiting CO₂ as a reaction medium would provide an attractive option for the enhanced generation of syngas and the tuned adsorption capability of biochar. © 2016 Elsevier Ltd.

This research was supported by Korea Ministry of Environment (MOE) as Waste to Energy recycling human resource development project.