Heat and flow dynamics in biomass reactors under pyrolysis conditions: Computational insights

Abstract

This study investigates the heat transfer and fluid flow phenomena in a tubular reactor designed for biomass pyrolysis, using both experimental and numerical methods. A comprehensive 3D Computational Fluid Dynamics (CFD) model was developed in COMSOL Multiphysics, incorporating the reactor geometry, operating parameters, and biomass properties to simulate thermal behavior. Experiments were conducted with chicken wing bones as feedstock, with temperatures monitored at three points along the reactor to validate the model. The simulations replicated experimental conditions, including nitrogen flow at 0.5 l/min and reactor wall temperature set at 550 °C.

The model accurately predicted temperature distributions and heat transfer within the reactor, with deviations below 5 % at steady-state. Results showed that thermal equilibrium was achieved at 960 s in the empty reactor and 1200 s in the reactor with biomass loaded at the center, with uniform temperatures of approximately 520–550 °C along the reactor. Axial and radial temperature uniformity was observed, though localized heat accumulation occurred in the reactor's middle section during early heating phases.

This research advances the predictive modeling of biomass pyrolysis by providing a validated tool for optimizing reactor design. These findings contribute to sustainable bioenergy technologies by improving reactor efficiency and enabling the effective utilization of organic feedstocks for bio-based products.