Time-Dependent Layer Formation Process on Quartz Bed Particles during the Fast Pyrolysis Process of Wood.

Area of Science:

• Biomass fast pyrolysis
• Materials science
• Chemical engineering

Background:

• Optimizing fast pyrolysis bio-oil (FPBO) production requires understanding bed particle layer formation.
• Limited research exists on ash-forming matter and bed material interactions during fast pyrolysis.

Purpose of the Study:

• Investigate the evolution and characteristics of bed particle layers on quartz during wood fast pyrolysis.
• Compare layer formation across different scales (bench, pilot, industrial).

Main Methods:

• Characterization of bed material samples using scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS).
• Detailed morphological and elemental analysis using focused ion beam-SEM (FIB-SEM).

Main Results:

• Bed particle layer formation during fast pyrolysis is similar to fluidized-bed combustion but results in thinner layers with less Ca.
• Layer formation involves initial Ca-rich ash deposition, Ca-silicate inner layer formation, and later development of K-Si-rich inner-inner layers.
• Layer thickness reaches a limiting value of approximately 4 μm over time.

Conclusions:

• The study elucidates the time-dependent characteristics and formation mechanisms of bed particle layers during wood fast pyrolysis.
• Findings provide insights for optimizing FPBO production by managing bed particle layer effects.