Effects of Particle Size on Cellulosic Biomass Pellets: A Literature Review

Abstract

Cellulosic biofuels are becoming an attractive alternative to conventional liquid transportation fuels. Cellulosic biomass is the feedstock for cellulosic biofuel manufacturing. However, high transportation and storage cost of cellulosic biomass due to its low density hinders large-scale and cost-effective manufacturing of cellulosic biofuels. Pelleting processes are used to produce biomass pellets which have higher density and are easier to handle in transportation and storage. Before going through pelleting processes, original cellulosic biomass materials are milled into particles. The particle size is an important input parameter in pelleting processes. Many investigations have been conducted on effects of biomass particle size on pellet quality (in terms of density, durability, stability, and strength). This paper reviews the literature about effects of particle size on pellet quality. Investigated biomass materials, selected range of particle size, utilized milling and pelleting processes are summarized. The approaches to evaluating pellet quality are also reviewed.