Influence of possible interactions between biomass organic components and alkali metal ions on steam assisted pyrolysis: a case study on Arundo donax

The influence of feedstock composition (organic and inorganic matrix) on the products yields and the liquid phase composition deriving from a slow steam assisted pyrolysis process was studied. To this aim slow steam assisted pyrolysis tests at 5 K/min and final temperature equal to 973 K were carried out on cellulose (pure and doped with Na and K ions), on a biomass model mixture of cellulose, xylan and lignin alkali and on Arundo donax canes, untreated and demineralized. Products yields were measured. Chromatographic techniques were applied to identify and quantify the main species in the gaseous and in the liquid fractions. This study showed that alkali metal ions affected both the devolatilization and gasification stages. More specifically, their presence depressed the levoglucosan yield due to cellulose decomposition and enhanced the production of CO2 and H2 in the gasification stage.