Experimental Test on Energy Conversion Efficiency and Environmental Impact of Maize Combustion

Direct combustion in small plants is the most well known and mature biomass energy conversion technology. Even though a lot of research has been made about different boiler working processes and about biomass characteristics, some aspects, about parameters optimization of a small boiler, are nowadays to investigate. In particular a very important parameter, that is to investigate for its influence on energy conversion efficiency, is the ratio between biomass and air mass flow rates. In this context, experimental tests results, on maize combustion in a commercial boiler, are analysed in this paper. By these experimental tests, it has been possible to define some curves that describe energy conversion efficiency behaviour as a function of thermic power. Environmental impact evaluations (in particular a continuous acquisition of most important parameters: powder, CO, TOC, NO2, SO2) show very low values. Solid residue are under 2%, but gives some problem with clinker that need to be break up before boiler stopping. Future developments deals with experimental tests on different kinds of biomass like hemp, fibre sorghum, switch grass and giant reed.