Upgrading co-pyrolysis products from ternary biomass: An investigative study of commercial and locally-made catalysts

Catalysts play a pivotal role in influencing product yields and compositions in pyrolysis processes, offering significant advantages for biomass conversion. This study investigates the impact of natural and commercial catalysts on the co-pyrolysis of ternary biomass at two different temperatures (550 °C and 750 °C). At higher temperatures, secondary decompositions become prominent, leading to increased gas yields and decreased char and liquid oil yields. The introduction of catalysts generally enhances char yields across both temperature regimes. Notably, CaCO₃ exhibits the highest bio-oil yield, while Ca(OH)₂ shows the lowest, with reversed trends observed for gas yields. The influence of catalysts extends to gas composition, with Ca(OH)₂ and zeolite notably increasing CH₄ and CO₂ concentrations at 750 °C. Each catalyst type exerts specific effects on gas production and composition, underscoring the intricate interplay between catalysts and reaction pathways. Additionally, catalysts significantly alter the composition of bio-oil, with calcium-based catalysts reducing acid content and increasing aromatics, while zeolites exhibit contrasting trends at different temperatures. Noteworthy compounds identified in the resulting bio-oil include bisphenol A, levoglucosan, phenols, and p-cresol, offering potential applications in plastics, biofuels, resins, and more. Overall, catalysts offer the potential to enhance specific compound yields, reduce corrosiveness, and optimize bio-oil and char composition for diverse industrial applications, highlighting the need for further research into synergistic effects when combining different catalysts.