Title:
Defining Uncertainties in the Size of Ground Biomass Particles
Author(s):
Naimi, L.J., Sokhansanj, S, Womac, A.R.
Document(s):
Paper
Abstract:
Preparation of biomass for conversion to heat and chemicals involves a number of operations including drying, size reduction, and fractionation. Among them, size reduction is an important operation because it consumes relatively high amount of energy in the form of electric power. Depending upon conversion technologies (combustion, gasification, pyrolysis and densification), a specific particle size would provide optimum yield of the highest quantity product. Biomass particles and especially those herbaceous have a large aspect ratio (length over diameter) and thus cannot be easily fractionated to a target single size. The distribution of length and diameter affects the packing characteristics and flowability of particles. In this research, switchgrass was ground in a screen¬less knife mill repetitively by recycling ground material back to the grinder. This operation emulated the length of time a biomass would reside in the grinder. The particle size of ground particles at the interval between cycles was analyzed. Length and diameter of particle fractions were measured. It was observed that as grinding cycles increase, the particles become smaller with reduced variations in size but reaching a plateau. The Weibull distribution function fitted the data better than the log-normal distribution. Particle variations in dimensions (length and diameter) on sieves are too large. These sieves cannot be used with certainty to fractionate particles to targeted dimensions (length or diameter).
Keywords:
switchgrass, characterisation, distribution
Topic:
R&D on Processes for Solid, Liquid and Gaseous Fuels from Biomass
Subtopic:
Production and supply of solid biofuels
Event:
20th European Biomass Conference and Exhibition
Session:
3DV.4.2
Pages:
1713 - 1716
ISBN:
978-88-89407-54-7
Paper DOI:
10.5071/20thEUBCE2012-3DV.4.2
Price:
FREE
