Part 1-Impact of Pyrolysis Temperature and Wood Particle Length on Vapor Cracking and Char Porous Texture in Relation to the Tailoring of Char Properties

Maziarka, Przemyslaw ; Kienzl, Norbert ; Dieguez-Alonso, Alba ; Fierro, Vanessa ; Celzard, Alain ; Arauzo, Pablo J. ; Hedin, Niklas ; Prins, Wolter ; Anca-Couce, Andrés ; Manyà, Joan J. (Universidad de Zaragoza) ; Ronsse, Frederik

Resumen: Pore size distribution is a key parameter in the performance of biobased pyrolytic char in novel applications. In industrial-scale production, the size of feedstock particles typically exceeds a few millimeters. For such particle sizes, it is a challenge to tailor the final properties of the char based only on the process conditions (experimental and modeling-wise). Pyrolysis studies of single particles larger than a few millimeters provide data sets useful for modeling and optimization of the process. Part 1 of this research focused on the pyrolysis of single particles of beech wood, secondary cracking, and its effect on the char porous texture. It contains a quantitative assessment of the effects of five conversion temperatures (from 300 to 840 °C) and two particle dimensions (Ø8 × 10 mm and Ø8 × 16 mm) on the composition of the pyrolysis vapors and pore morphology of the char. Results from real-time temperature and mass changes are presented along with release profiles of 15 vapor constituents measured by infrared spectroscopy. Furthermore, characterization of the collected bio-oil (using GC-MS/FID) and the textural hierarchical structured char (through N2 and CO2 adsorption, Hg porosimetry, and scanning electron microscopy (SEM)) was performed. Cracking of vapors above 500 °C was compound-specific. The polyaromatic hydrocarbons (PAHs) yield, between 680 and 840 °C, increased 5 times for 10 mm particles and 9 times for 16 mm ones. Besides temperature, PAH yield was suspected to correlate with particle length and PAHs/soot deposition in the micropores. Results showed that the macropores accounted for over 80% of the total pore volume, regardless of the temperature and particle length. Increasing the particle length by 60% caused a reduction in the specific surface area (ca. 15% at 840 °C) of the resulting char, mainly due to a reduction in microporosity. Based on the findings, the production conditions for a specific char application are suggested. The obtained data will be used in Part 2 of this research, devoted to subsequent CFD modeling of the process.

Idioma: Inglés

DOI: 10.1021/acs.energyfuels.4c00937

Año: 2024

Publicado en: Energy and Fuels 38, 11 (2024), 9751–9771
ISSN: 0887-0624

Financiación: info:eu-repo/grantAgreement/EC/H2020/721991/EU/Advanced Carbon Materials from Biowaste: Sustainable Pathways to Drive Innovative Green Technologies/ GreenCarbon
Financiación: info:eu-repo/grantAgreement/EC/H2020/731101/EU/ Biofuels Research Infrastructure for Sharing Knowledge II/BRISK II

Tipo y forma: Artículo (PostPrint)

Área (Departamento): Área Ingeniería Química (Dpto. Ing.Quím.Tecnol.Med.Amb.)