Catalytic pyrolysis of green algae: Influence of catalysts on thermal degradation behavior and product distribution

Abstract The catalytic pyrolysis of green algae (GA) was conducted using both a thermogravimetric analyzer and a horizontal tube reactor. Five catalysts – biochar, potassium hydroxide (KOH), sodium hydroxide (NaOH), ethylene glycol dimethyl ether (EGDE), and Zeolite Socony Mobil‐5 (ZSM) – were tested. Kinetic analysis was performed using the Friedman method to estimate activation energy, and the master plot method, combined with regression analysis, was employed to determine a suitable reaction model. The pyrolysis products were quantitatively characterized. The results showed that the presence of catalysts influenced the kinetic parameters and product yields. Activation energy values for the noncatalytic GA sample ranged from 124.92 to 299.39 kJ mol −1 , whereas catalytic samples exhibited a broader range of 110.79 to 358.30 kJ mol −1 . The use of catalysts generally increased solid and liquid yields, and this was accompanied by a decline in gas yield. The volumetric yield of gaseous components generally increased with temperature. Among these gases, CO 2 had the highest volumetric yield, followed by CO, CH 4 , H 2 , and C 3 H 6 . These results highlight the role of catalysts in influencing the pyrolysis process and product yields.