Catalytic pyrolysis of brown algae using carbon dioxide and oyster shell

Abstract

In this work, the pyrolysis of brown algae (Saccharina japonica (S. japonica)) was investigated to recover energy as a form of syngas (H2 and CO). For this, this work emphasizes the use of CO2 as a pyrolysis medium and oyster shell as a catalytic material in the pyrolysis of S. japonica. Pyrogenic products generated from the catalytic pyrolysis of S. japonica in N2 and CO2 were characterized. In particular, the enhanced generation of CO was substantial at 720 °C. This enhanced generation of CO was most likely because of the enhanced thermal cracking of volatile matter that evolved during the catalytic pyrolysis of S. japonica. The enhanced CO generation was likely catalytically expedited by biogenic salts such as calcite (CaCO3) in the oyster shell. The introduced approach for exploiting CO2 in the catalytic pyrolysis could be a more sustainable option to treat algal biomass such as brown algae and develop an effective waste-to-energy strategy.