Viability Evaluation of Three Grass Biofuels: Experimental Study in a Small-Scale Combustor

Abstract

This experimental study focusses on the viability of three low-grade biofuels in small-scale biomass units of 7–12 kW The tested materials were homemade grass pellets (gp1 and gp2) and a mixture of leaves and woody pellets (lp50) that were made without binders and completely characterized in terms of their chemical and physical properties (proximate analysis, elementary composition, ash content, flowability, etc.). The results obtained with the non-commercial fuels were compared with commercial wood pellets (wp). The viability study comprised the operational parameter influences, such as primary and secondary airflow, fuel consumption, etc., together with the impact of those parameters on the main problems in combustion (concentration and particle distribution, fouling and slagging). The results revealed that the biomass whose behavior during combustion induced fewer particulate emissions and deposits was the mixed fuel, made of 50% leaf + 50% wood pellet (lp50). Contrary to the grass-based pellets, lp50 has the possibility of being used in commercial devices with the incorporation of processes during the manufacturing that improve their properties.