Experimental investigation of Single-Particle Biomass Pyrolysis Under High-Intensity Acoustic Fields

This work experimentally investigates the effect of externally applied acoustic fields on the pyrolysis of a single biomass particle, assessing the potential of acoustic excitation as a process-intensification mechanism. Pyrolysis experiments are conducted using an isolated cylindrical biomass particle with a characteristic diameter of 10 mm under an inert atmosphere. Reactor temperature, acoustic frequency, and sound pressure level are systematically varied, with sound pressure levels reaching up to 130 dB. The application of acoustic fields alter heat and mass transfer processes within and around the particle by enhancing boundary-layer disruption and volatile transport. To enable these experiments, a novel test bench was designed and experimentally validated. The experimental results are compared with model predictions obtained using a proprietary numerical code. Key response variables include devolatilization rate, mass-loss behavior, and char characteristics. This single-particle approach enables direct observation of the coupling between thermal decomposition and acoustic excitation while avoiding bed-scale interactions. The results provide insight into the fundamental mechanisms governing acoustically assisted pyrolysis at the particle scale and to support the development of acoustically intensified thermochemical conversion processes. This study contributes to the understanding of sound-assisted biomass conversion and its potential application in advanced pyrolysis reactor designs.