(2024) Chemical Engineering Journal_Controlling the compositional matrix of pyrogenic products using carbon dioxide in the pyrolysis of agricultural plastic waste

Lee D.-J.; Park J.; Kim J.Y.; Jung S.; Choi Y.-B.; Park S.; Seo S.; Tsang Y.F.; Kwon E.E.

(Elsevier B.V.) Chemical Engineering Journal ISSN: 13858947 Vol.482 Issue. Article No.148968 DOI: 10.1016/j.cej.2024.148968

Plastics are extensively employed in agriculture, generating an enormous volume of plastic waste. This study investigated the pyrolysis of silage film waste (SFW) to enable its conversion into energy/value-added chemicals. CO₂ was chosen as the reactive medium to provide green pyrolysis. Nevertheless, the results showed that most of the carbon in the SFW was assigned to wax-like oil formed by thermal cracking. It was presumed that the reactivity of CO₂ was effective only under certain optimal temperature conditions. To this end, the test setup was modified to increase the residence time of the reactants (CO₂ and volatiles from SFW). With respect to inert gas conditions, syngas formation was observed under CO₂ conditions. The enhanced formation of syngas was realised by the simultaneous reduction of CO₂ into CO and the oxidation of volatiles into CO. CO₂ also enhances the thermal cracking of volatiles, leading to enhanced formation of C₂-hydrocarbons. These features provide an effective means of decreasing the aromaticity of oil from SFW pyrolysis. The simultaneous reduction of CO₂ into CO and oxidation of volatiles into CO block the mechanistic pathway to form polycyclic aromatic hydrocarbons. CO enhancement by CO₂ offers an effective means for abating the fate of toxic chemicals. © 2024 Elsevier B.V.

This work was carried out with the support of “Cooperative Research Program for Agriculture Science and Technology Development (Project No. RS-2022-RD010000)” Rural Development Administration, Republic of Korea.