Biomass Torrefaction Under High Intense Acoustic Fields
biomass energy; acoustic field; torrefaction; pyrolysis; finite difference.
Biomass particles were subjected to a uniform flow, under the influence of an acoustic field. The modeling consists of the numerical solution of the energy equation and Fick's second law. The hypotheses are for spherical particles, laminar flow in transient regime, for a temperature range between 200 and 300 ºC until the particle degrades to the torrefaction level. Moisture concentration and temperature fields were simulated considering the interior of the particle as a control volume. The model also simulated the variation of the particle mass and the plotting of the velocity and trajectory profile. Changes were observed in the heat and mass transfer coefficients with reflections on the drying and degradation of the particle. Different values of frequency, residence time, amplitude velocity and particle sizes were considered in the simulations. The dry mass variation was elaborated by the chemical kinetics model described by the Arrhenius equation. Kinetic parameters were combined with elemental analysis modeling to calculate performance parameters such as mass densification, energy densification, higher heating value (HHV) increment and energymass co-benefit index (EMCI). The design of a pyrolysis reactor using the output gases of a microturbine was presented as a model application and a suggestion for further studies.