Towards a sustainable waste-to-energy pathway to pequi biomass residues: Biochar, syngas, and biodiesel analysis
Abstract
The waste-to-energy (WTE) valorization pathway of Caryocar brasiliense (pequi) seeds was investigated via pyrolysis, gasification, and transesterification to understand its potential as biochar, syngas, and biodiesel. First, the pyrolysis (300-700 °C) was conducted in N 2 atmosphere for pequi seeds (PS) and pequi seeds without its extractives (PSWE), characterizing its biochar properties. The PSWE was then gasified at 1000 °C under O 2/N 2, O 2/CO 2/N 2 and O 2/H 2 O/N 2 atmospheres to evaluate the characteristics of the producer gas. The PS extractives were then transesterified and characterized for biodiesel production. Finally, a multiple-criteria decision analysis assessed the PS products' potential within the thermochemical routes. The results evidenced better biochar (up to 22.29% HHV enhancement, higher mass and energy yield, up to 75.9 and 85.5% reduction of O/C and H/C, respectively, and enriched N content) via PSWE pyrolysis than PS considering biofuel application and optimistic perceptions for soil amendment. This indicates that the preceding extraction of vegetal fat from PS strengthens the WTE by including further processing of extracted oil. The produced syngas under O 2/H 2 O/N 2 gasification atmosphere showed better applicability as a biofuel (16.37 MJ·kg-1 lower heating value, 107.33% cold gas efficiency, and 113.55% carbon conversion efficiency) with up to 24% higher success rate. The transesterification of the extractives revealed its potential (98% conversion rate) for use as feedstock for in situ power generation, or blended for biodiesel production. The results provide insights into the circular economy in agro-extractivist communities that may support Brazil's small and medium agro-food industries with their energy demands.
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Diverse processing pathways exist for converting microalgal biomass into biofuels, including biochemical methods like fermentation or anaerobic digestion, thermochemical methods such as pyrolysis or gasification to produce intermediates like bio-oil or syngas, and lipid extraction followed by transesterification to yield biodiesel.
“Diverse processing pathways exist for converting microalgal biomass into biofuels, including biochemical methods like fermentation or anaerobic digestion, thermochemical methods such as pyrolysis or gasification to produce intermediates like bio-oil or syngas, and lipid extraction followed by transesterification to yield biodiesel [163,164].”
From Biofuels, E-Fuels, and Waste-Derived Fuels: Advances, Challenges, and Future Directions (2025) · cites this paper as [163]
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Apolinar-Hernández, J. E., Bertoli, S. L., Riella, H. G., Soares, C., & Padoin, N. (2024) · Energy & Fuels · doi:10.1021/acs.energyfuels.3c02287 · Cited by 46 · see citing works
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- Authors
- Ghesti, G. F., Silveira, E. A., Guimarães, M. G., Evaristo, R. B. W., & Costa, M.
- Affiliations
- Universidade de Brasília (BR)
- University of Lisbon (PT)
- Corresponding author
- Ghesti, Grace F.
- Silveira, Edgar A.
- Venue
- Waste Management
- Publisher
- Elsevier BV
- Published
- 2022-04
- Volume
- 143
- Pages
- 144-156
- ISSN
- 0956-053X (ISSN-L)
- OpenAlex
- W4220866262
- Cited by
- 69
- References
- 72
- Citations by year
- 2026: 8 · 2025: 21 · 2024: 13 · 2023: 18 · 2022: 9
- FWCI
- 4.43
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- Locations
- Waste Management (publishedVersion)
- PubMed (publishedVersion)
- Funders
- CAPES
- CNPq
- FAPDF
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Thermochemical Biomass Conversion Processes
- Physical Sciences › Engineering › Biomedical Engineering › Biodiesel Production and Applications
- Life Sciences › Agricultural and Biological Sciences › Forestry › Agricultural and Food Sciences
- Keywords
- Caryocar brasiliense, waste-to-energy, pyrolysis, gasification, transesterification, biochar, syngas, biodiesel, vegetable oil extraction, multi-criteria decision making, circular economy, soil amendment
- MeSH terms
- Pyrolysis, Charcoal, Biomass, Biofuels
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