(2020) Journal of Cleaner Production_Exploiting starfish in pyrolysis for the enhanced generation of syngas and CO₂-looping agent

Kim Y., Jung S., Park Y.-K., Moon D.H., Kwon E.E.

(Elsevier Ltd) Journal of Cleaner Production ISSN: 9596526 Vol.276 Issue. Article No.123228 DOI: 10.1016/j.jclepro.2020.123228

Starfish (Asterina pectinifera) has been considered a major invasive species with no natural predators in the marine ecosystem. They can destroy the natural marine system when the population growth is too high, suggesting the development of a sustainable way to dispose of starfish. Therefore, this study offers a sustainable thermo-chemical platform for the direct conversion of starfish waste into value-added syngas (CO and H₂) and biochar. Major gaseous products from the starfish pyrolysis under both the N₂ and CO₂ conditions were H₂, CH₄ and CO. H₂ and CH₄ were likely ascribed to dehydrogenation and C–C bond scission of starfish, while CO formation was from homogeneous reaction of CO₂ with volatile organic matters from starfish pyrolysis. Under the N₂ environment, CO₂ liberated from the thermolysis of CaCO₃, a major constituent of starfish, contributed to formation of CO. Such the mechanistic effectiveness of CO₂ was confirmed by starfish pyrolysis under the CO₂ environment. However, the effectiveness of CO₂ on gas phase homogeneous reaction with volatile compounds was not fully activated during thermolysis in one-stage pyrolysis due to source depletion at high temperature. To improve the effectiveness of CO₂, additional thermal energy was applied through two-stage pyrolysis (isothermal running at 600 °C). The homogeneous reaction of CO₂ with volatile compounds liberated from starfish pyrolysis with additional thermal energy highly contributed to enhanced formation of CO. In line with the substantial generation of CO in the presence of CO₂, high concentration of CO₂ also contributed to more pore creation. These observations indicate that the construction of CO2-looping system from starfish pyrolysis would become a sustainable way to produce syngas and porous biochar. © 2020 Elsevier Ltd

.This work is financially supported by Korea Ministry of Environment (MOE) as Graduate School specialized in Climate Change.