Biofuels from broom clearings: production and combustion in commercial boilers

Abstract

Shrub lands could provide an almost unexplored biomass resource of increasing potential in the EU, particularly in Mediterranean countries. Its collection and transformation into solid biofuels will help to reduce the adverse effects associated with frequent shrub land fires. The objective of this study is to examine the pre-treatment and combustion of biomass obtained from broom plant clearings to assess the feasibility of utilising it as a fuel in commercial combustion applications. Above ground broom biomass was collected with a harvester-baler machine. Afterwards, in a milling installation and a pilot pelletisation plant two fuels were obtained: 30 mm milled material and pellets, which were used in two commercial grate boilers (40 kWth and 500 kWth). We conclude that biomass from broom clearings could be used to produce solid biofuels for commercial boilers. Milling and pelletisation did not entail difficulties and the pellets could be classified as B (ISO 17225-2:2014). During combustion, no operating problems related to the fuel were observed. However, due to its high potassium content, special attention should be paid to the tendency to produce deposits and to particle emission and it would be advisable to control the working temperature to avoid slag formation in the burner.