PYROLYSIS OF GIANT REED (ARUNDO DONAX) FOR PRODUCTION OF BIOCHAR

Arundo donax (L.) is one of the most important energy crop, but its use in the pyrolysis process have not yet been thoroughly tested. Pyrolysis is a suitable technique to manage residual biomass. One byproduct of the process is the biochar, a carbon-rich residue used in agriculture as soil conditioner. Biomass of Arundo was shredded in order to produce a greater (G) and a smaller (S) particle size distribution (PSD) of the feedstock. Both were gasified in a small scale up-draft reactor at three rates of air flow (0.0007 m(3) s(-1), 0.001 m(3) s(-1) and natural draft). Aim of the work was to analyze the effect of different air flow rate and two PSD on the main parameters characterizing the biochar (yield, calorific value, proximate analysis). Results showed that the interaction P SD-air flow has to be set properly to obtain a high-grade biochar. Using a greater PSD, the biochar yield improved (24.3% vs 15.2%) and the LHV was higher than the smaller PSD at 0.0007 m(3) s(-1), 0.001 m(3) s(-1). The highest carbon content (90.40%) was obtained with the greater PSD in conditions of natural draft (air almost completely absent). Further studies would be required to identify the upper limit beyond which the process becomes inefficient.