Effect of Size and Shape on Pyrolysis Dynamics of Cylindrical Biomass Particles: A Computational and Experimental Approach

Abstract

A computational model for cylindrical particle pyrolysis was developed to analyze the fundamental thermal and material transport properties in biomass particles, aiming to optimization the biomass pellet parameters and operation conditions. The model investigates the mass and heat transport processes during pyrolysis for cylindrical particles with diameters varying from 4 to 30 mm and aspect ratios (AR = L/D) between 0.5 and 5. The operating conditions include pyrolysis temperature of 425°C, 500°C, 600°C, and heating rate of 10°C/min, 20°C/min, 30°C/min, 40°C/min, and 50°C/min. The accuracy of the model's predictions was validated through single-particle pyrolysis experiments. Numerical simulation of weight loss during pyrolysis showed strong agreement with experimental results. The numerical predictions indicate that for a constant volume, increasing the AR enhances the proportion of lateral surface area to the total surface area. This results in greater heat transfer through the sides, reducing radial temperature gradients and heat penetration to the particle’s core in higher aspect ratio particles.

Keywords: Biomass pellet, pyrolysis, Heat transfer, Computational model, Aspect ratio