Optimized production of aromatic hydrocarbons via corn stover pyrolysis: Utilizing high-density polyethylene as a hydrogen donor and red mud as a catalyst

Biomass pyrolysis offers a promising route for high-value bio-oil production, yet the process is limited by low deoxygenation efficiency. In this study, high-density polyethylene (HDPE) served as a hydrogen donor, and acidwashed red mud (ACRM) acted as a catalyst to enhance the pyrolysis of corn stover (CS) for producing monocyclic aromatic hydrocarbons (MAHs). The results showed that the addition of ACRM significantly reduced the activation energy for co-pyrolysis, enhanced the reaction rate, and strengthened the synergistic effects between CS and HDPE. Optimal conditions yielded a MAHs selectivity of 64.5 % at 650 degrees C with a CS: HDPE ratio of 1:1. However, excessively high temperatures facilitated the cyclization and polymerization of MAHs into polycyclic aromatic hydrocarbons, while a high HDPE ratio diminished the synergistic effects. Furthermore, recycling tests confirmed the effective reusability of ACRM, with MAHs yields remaining above 40 % after four cycles. This study highlights the potential for valorizing industrial and agricultural wastes.