Insight into synergistic effects of biomass-polypropylene co-pyrolysis using representative biomass constituents.

The co-pyrolysis behavior of plastic (PP) with six biomass components (cellulose, hemicellulose, lignin, carbohydrate, lipid, protein) was studied by thermogravimetry. The overlap ratio (OR) and the difference in experimental and theoretical weight loss (ΔW) are defined. The results demonstrated that the interaction of lignin and PP was notable with the OR of 0.9661. From ΔW, it was found that the number of solid residues of hemicellulose-PP and lignin-PP decreased by 1.10% and 2.60%, respectively, which was caused by the hydrogenation reaction between the monomers generated by PP and biochar. The DTG peak shift in co-pyrolysis was further studied. By blending with the biomass, the pyrolysis peaks of PP shifted to the high-temperature region and the value was positively correlated with the fixed carbon content in the biomass components. Kinetic analysis revealed that by co-pyrolysis with biomass, the activation energy of the PP decomposition could be reduced by 39.51% -62.71%.