Densification and combustion of biomass pruning residues

This paper addresses the potential of biomass pruning residues for energetic valorization by combustion. For this, five representative types of woody biomass pruning residues were collected and its proximate and ultimate composition determined. After a period of natural drying, the biomass was densified by briquetting technique. The produced briquettes were characterized and burned in a downdraft wood gasification boiler. Flue gas was sampled and analyzed in terms of temperature, flow speed, moisture and O2 and CO2 composition. Pollutant emission was measured, namely CO, NOx, TOC and PM. The results are discussed and compared to conventional briquettes made from pine sawdust and show that briquetting is an effective technique to densify the pruning biomass and its possible to burn on conventional boilers. Pollutant emission it’s only a concern for NOx, for which adequate NOx emission reduction techniques are advised.