Enhancement of energy recovery from chicken manure by pyrolysis in carbon dioxide

Herein, pyrolysis of chicken manure is investigated to establish a sustainable platform for the disposal of chicken manure while efficiently recovering energy as a form of syngas. To this end, this study lays great emphasis on the exploitation of CO₂ in pyrolysis of chicken manure. As an initial assay for the role CO₂ in the pyrolysis process, thermal degradation of chicken manure in N₂ and CO₂ is characterized thermo-gravimetrically. Except the temperature regime (≥720 °C) governed by the Boudouard reaction, the TGA results with chicken manure do not reveal any differences associated with physical aspects such as onset and end temperatures. For in-depth study, pyrogenic products generated from pyrolysis of chicken manure in N₂ and CO₂ are characterized. Particularly, an enhanced generation of CO is substantial at temperatures higher than 500 °C. This enhanced generation of CO is likely due to an enhanced thermal cracking behavior of volatile organic carbons (VOCs) evolved from pyrolysis of chicken manure. The enhancement of CO generation is catalytically expedited by biogenic salt such as calcite (CaCO₃) in chicken manure. The introduced approach for utilizing CO₂ in pyrolysis could be a sustainable option to treat biowaste such as chicken manure along with developing an effective waste-to-energy strategy.