Integrated valorization of oil palm waste via CO2-Assisted slow Pyrolysis: Enhanced biochar, tailored bio-oil, and economic viability
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Issued Date
2025-10-01
Resource Type
ISSN
09619534
eISSN
18732909
Scopus ID
2-s2.0-105008297694
Journal Title
Biomass and Bioenergy
Volume
201
Rights Holder(s)
SCOPUS
Bibliographic Citation
Biomass and Bioenergy Vol.201 (2025)
Suggested Citation
Rodto K., Serafin J., Chaemchuen S., Klomkliang N. Integrated valorization of oil palm waste via CO2-Assisted slow Pyrolysis: Enhanced biochar, tailored bio-oil, and economic viability. Biomass and Bioenergy Vol.201 (2025). doi:10.1016/j.biombioe.2025.108108 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/110846
Title
Integrated valorization of oil palm waste via CO2-Assisted slow Pyrolysis: Enhanced biochar, tailored bio-oil, and economic viability
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Abstract
This study systematically investigates the CO<inf>2</inf>-assisted slow pyrolysis of oil palm leaf biomass, focusing on the influence of operating parameters—including carrier gas flow rate, reaction time, temperature (400–800 °C), CO<inf>2</inf>/N<inf>2</inf> gas composition, and limestone catalyst loading—on the yield and properties of biochar, heavier bio-oil (HBO), lighter bio-oil (LBO), and syngas. Pyrolysis temperature was identified as the dominant factor controlling product distribution, while the introduction of CO<inf>2</inf> significantly increased LBO and biochar yields and altered the physicochemical pathways of decomposition. The BET surface area of the biochar was enhanced from 4.78 to 333.35 m<sup>2</sup>/g with the combined effect of high temperature, CO<inf>2</inf>-rich atmosphere, and catalyst addition, which resulted in the highest heating values of HBO (25.80 MJ/kg) and syngas (4.27 MJ/Nm<sup>3</sup>). The maximum yields of HBO (18.65 wt%) and LBO (13.53 wt%) occurred at 700 °C under a CO<inf>2</inf>-rich atmosphere. CO<inf>2</inf> atmosphere also promoted the formation of acetic acid in bio-oils, while increasing CO content in the syngas fraction. Catalyst addition (CaCO<inf>3</inf>) induced in situ neutralization of carboxylic groups in the bio-oil, reducing acid content and enriching ketonic and phenolic species. GC-MS analysis revealed marked shifts in oxygenated and N-heterocyclic compound profiles in bio-oil products across pyrolysis conditions and aging periods. Techno-economic analysis using Aspen Plus shows that the integrated CO<inf>2</inf>/catalyst system achieves the lowest total investment cost over a 10-year operation period with payback period in 8.3 years. These results provide key insights into the design of CO<inf>2</inf>-mediated pyrolysis systems for integrated biomass valorization and negative-emissions carbon materials.