Strategic use of CO₂ for co-pyrolysis of swine manure and coal for energy recovery and waste disposal

Here in this study, the genuine role of CO₂ in co-pyrolysis of swine manure and coal was mainly investigated to increase the thermal efficiency of the thermo-chemical process. The TGA test of swine manure and coal revealed that the CO₂ co-feeding impact on any reactions (≤740 °C) between CO₂ and the sample surface (i.e., heterogeneous reaction) should be excluded. A batch-type co-pyrolysis revealed two genuine CO₂ co-feeding impacts on co-pyrolysis of swine manure and coal. First, CO₂ can be an additional source for C and O through a plausible reaction between pyrolytic oil and CO₂, which led to the enhanced generation of CO by the conversion of volatile organic carbons (VOCs) evolved from thermal deconstruction of pyrolytic substrate. Second, CO₂ expedite the thermal cracking of VOCs, which also resulted in the more generation of H₂ and CH₄. Two genuine roles of CO₂ in co-pyrolysis of swine manure and coal occurred independently. All experimental findings will be directly applicable to the gasification process since pyrolysis is an intermediate step for the gasification.