Thermal Behaviour and Emission Characteristics of Arundo donax L. as Potential Biofuel

The study evaluates the potential of Arundo donax L., a perennial herbaceous that can grow in wide varieties of soils with minimal water and nutrient requirements, as a solid biofuel for the production of thermal energy. The biomass was characterized in terms of proximal, chemical, and elemental analysis using standard techniques. The combustion behaviour and thermal efficiency were evaluated by using a domestic stove through the Water Boiling Test. The gaseous emissions from the combustion of Arundo donax L. were measured with a portable device and compared with those from other conventional biomasses such as pine pellets, corn cobs, and commercial firewood. The results showed a higher heating value of 17.36 +/- 0.171 MJ/kg and an elemental composition based on more than 45% carbon. The WBT revealed both, the shortest time (27.8 min) and the specific fuel consumption (1.1 kg/L), and the highest burning rate (88.8 g/min) for Arundo donax L. compared to the rest of the biomasses studied. The flue gas profile revealed CO2 emissions of 2.6%, similar to pellets and commercial firewood (1.3 and 1.9%, respectively), a percentage of CO lower than corn cobs, although somewhat unstable, and NOx emission of around 197 mg/Nm(3) only higher than pine pellets. These results revealed the technical viability of Arundo donax L. as a biofuel for thermal energy production, at least at residential level, contributing to the diversification of renewable sources of bioenergy in a sustainability scenario against climate changes effects.