Characterization and bio-oil analysis of microalgae and waste tires by microwave catalytic co-pyrolysis

Waste tires (WT) are difficult to degrade in natural conditions, but co-pyrolysis with other substances can release environmental pressure. Thus, microwave catalytic co-pyrolysis of WT and Chlorella vulgaris (CV) were studied. The effects of material mixing ratio, catalysts (NiO, CoO and CeO) and their addition amounts (5%, 10%, 15% and 20%) on the co-pyrolysis were analyzed. The results showed that bio-oil yield was boosted by co-pyrolysis and the maximum value (19.77%) appeared at C6W4 (CV:WT = 6:4). While adding 15%NiO, the maximum yield of bio-oil increased by 8.66%. Compared with CV pyrolysis alone, the deoxidation rate, denitrification rate, and desulfurization rate of C6W4 were as high as 44.57%, 59.82% and 52.59%, respectively. Catalysts improved the quality of bio-oil, the highest hydrocarbon content (58.3%) and denitrification rate (27.07%) were obtained at the 15%NiO. The highest aromatic hydrocarbon content (33.2%) and deoxygenation rate (10.31%) appeared in 15%CoO. [Display omitted] •CV and WT co-pyrolysis with different mixing ratios and catalysts.•Co-pyrolysis improved the yield and quality of bio-oil.•The addition of 15% NiO promoted the co-pyrolysis characteristic significantly.•Catalysts increased the hydrocarbons and reduced nitrogen and oxygen compounds.•15%NiO had the largest hydrocarbon content and denitrification rate.