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Co-pyrolysis of microalgae and plastic: Characteristics and interaction effects

Tang, Ziyue, Chen, Wei, Chen, Yingquan, Yang, Haiping, Chen, Hanping
Bioresource technology 2019 v.274 pp. 145-152
Nannochloropsis, carbon dioxide, ethylene, liquids, methane, microalgae, mixing ratio, nitrogen compounds, oils, polyethylene, pyrolysis, pyrolysis oils
To improve the quality of the oil produced from microalgae, the co-pyrolysis of low-density polyethylene (LDPE) and Nannochloropsis sp. (NS) in a fixed bed reactor was investigated at different mixing ratios. Co-pyrolysis improved the gas yield, and the lower heating value of the gas products increased obviously with an increase in the LDPE amount. Furthermore, co-pyrolysis promoted the generation of CH4 and C2+, especially C2H4, with the maximum C2+ yield (84.86 mL/g) obtained with 75% LDPE. Meanwhile, the amounts of oxygenous and nitrogenous compounds in the liquid products decreased rapidly with LDPE addition. The aliphatic hydrocarbon content of the liquid products increased from 22.63% for NS pyrolysis to 77.4% with 25% LDPE. During co-pyrolysis with LDPE, O tended to evolve as H2O and CO (rather than as CO2 for NS pyrolysis) and N was more likely to be released into gas products, which enhanced the quality of the pyrolysis oil.