Production of flammable gases from cattle manure via pyrolysis using CO₂ as an oxidant

To valorize disposed animal manure into flammable gases, pyrolysis of cattle manure (CM) was investigated in this study. To make this process more efficient and environmentally benign, CO₂, a greenhouse gas, was harnessed as a reactive gas. In CO₂-assisted pyrolysis of CM, enhanced CO production was observed, compared to pyrolysis from inert condition (N₂). The gas-phase reactions between CO₂ and gaseous biocrude produced from CM thermolysis led to improved CO formation. In reference to the case of lignocellulosic biomass (rice straw), 5 times more CO production was observed from CM pyrolysis under CO₂. For an in-depth study of CO₂ functionality as an oxidant, the effects of operational parameters on syngas formation were considered. The key parameter to activate the functionality of CO₂ was temperature. These results offer that CO₂ and CM could be considered promising reactants to produce value-added syngas in line with mitigation of pollutant emissions through a pyrolysis platform.