The promoting and inhibitory mechanism of interaction between waste tires and Spirulina on their co-pyrolysis

Energy utilization of biomass and waste is an important thrust for carbon emission reduction. Co-pyrolysis is conductive to efficiently converting algae and waste tires, due to their complementary pyrolysis characteristics. However, the influence of the interaction between algae and waste tires on co-pyrolysis behavior is still controversial, due to the internal mechanism of interaction is unclear. Therefore, in this study, mechanism experiments and theoretical calculations were used to comprehensively investigate the interaction mechanism between Spirulina (SP) and waste tires (WT). The co-pyrolysis of SP and WT can be divided into two main steps: low-temperature SP decomposition and high-temperature WT decomposition. The activation energies of WT and mixture increase with the conversion rate, while those of SP change little at low conversion rates (<60 %). The pyrolysis activation energies of mixture are lower than the theoretical values, as the blending ratio of SP below 50 %. The interaction between SP and WT has both promoting and inhibiting effects on the pyrolysis of mixture. The attack of free radicals from SP pyrolysis and ash in WT promotes the pyrolysis of mixture, but the low-temperature polymerization reactions and high-temperature aromatization reactions inhibit the release of pyrolysis products. The formation of benzene compound is promoted due to the attack of free radicals and the polymerization between SP and WT.