High-grade biofuel production from catalytic pyrolysis of waste clay oil using modified activated seaweed carbon-based catalyst

In the present study, seaweed char-based catalyst was used for pyrolysis of waste clay oil to obtain high-grade biofuels. First, the biochar was activated at different temperatures of 600, 700, and 800 °C (Y600, Y700, and Y800, respectively). The specific surface area of seaweed char prepared by activation at 800 °C reached the maximum value (1227.74 m2/g), which was a good catalyst carrier. Then modified by Cu loading. Results showed that the seaweed carbon-based catalyst has a good decarboxylation effect. The obtained liquid product under catalytic pyrolysis showed the maximum heating value of 48402 kJ/kg by using 15% Cu/Y800 as a catalyst at feed/catalyst ratio of 10:1; with the highest hydrocarbon content, the content of long-chain hydrocarbons and aromatic hydrocarbons being 45.95% and 41.45%, respectively. The decarboxylation effect of Cu-modified seaweed char was obvious, and the copper particles distributed on the seaweed char form active sites, which effectively reformed the pyrolysis volatiles and promotes the production of hydrocarbons, especially aromatic hydrocarbons Therefore, the modified seaweed char-based catalyst has a certain aromatization effect. At the same time, the hydrogen content in the gas-phase product decreased significantly, which may be due to the hydrogenation reaction under the action of catalysis.