Strategies towards thermochemical valorisation of spent coffee grounds (SCG): Kinetic analysis of the thermal and thermo-oxidative decomposition
[EN] The thermochemical conversion of spent coffee grounds (SCG) under inert and oxidative atmospheres was comprehensively assessed as a feasible valorisation route for this biomass. Dynamic thermogravimetric analyses were performed at different heating rates. The individual contributions of the pse...
| Autores: | , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/207440 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/207440 |
| Access Level: | acceso abierto |
| Palabra clave: | Biomass Spent coffee ground Kinetic analysis Pyrolysis Combustion MAQUINAS Y MOTORES TERMICOS |
| Sumario: | [EN] The thermochemical conversion of spent coffee grounds (SCG) under inert and oxidative atmospheres was comprehensively assessed as a feasible valorisation route for this biomass. Dynamic thermogravimetric analyses were performed at different heating rates. The individual contributions of the pseudo-components (hemicellulose, cellulose, and lignin) were determined by deconvolution using Lorentzian functions. For each pseudo-component, the kinetic triplet—apparent activation energy (Ea), pre-exponential factor (A), and reaction model (g(α))—was established by combining isoconversional methods, master-curve analysis, and the Pérez-Maqueda criterion. Under inert conditions, distinct mass-loss steps were identified corresponding to moisture release, decomposition of hemicellulose and cellulose and partial lignin degradation, followed by completion of lignin decomposition, leaving ~20% biochar. The Ea values were 217 kJ·mol⁻¹ (hemicellulose), 214 kJ·mol⁻¹ (cellulose), and 151 kJ·mol⁻¹ (lignin). Under oxidative conditions, similar stages were observed; however, the biochar was further oxidised, yielding only ash as residue (~2%). These results support the use of SCG as a solid biofuel, given its high LHV and HHV (≈20 MJ·kg⁻¹). The Ea values under oxidative conditions were 194 kJ·mol⁻¹ (hemicellulose), 147 kJ·mol⁻¹ (cellulose), and 173 kJ·mol⁻¹ (lignin). Similar decomposition behaviours were obtained regardless of atmosphere for hemicellulose (F4), cellulose (D3), and lignin (F2/4), suggesting that temperature, reactant concentration, particle morphology, and product diffusion govern SCG decomposition during non-isothermal pyrolytic and combustive thermochemical processes. |
|---|