The decomposition of five different biomass samples was studied in a thermobalance.The samples consisted of esparto grass, straw, Posidonea Oceanic seaweed, waste from urban and agricultural pruning and waste of forest pruning. Both pyrolysis in inert atmosphere and combustion in the presence of oxygen were studied. Different heating rates were used and a global kinetic model, valid for all biomasses at the different conditions studied, was proposed. The kinetic model is able to fit all the runs performed with each biomass sample.

HIGHLIGHTS-Posidonia oceanica thermal decomposition is studied. -Combustion, pyrolysis and gasification at different experimental conditions are performed.-The combined effect of the presence of oxygen, air, water vapor and dolomite in the decomposition bed is analysed. -Conditions where maximum ratio H 2 /CO is observed are optimized. ABSTRACTIn the present work, a very detailed study of the reforming of syngas produced in the decomposition of Posidonia oceanica is done. The effect of the presence of different amounts of dolomite is analysed. Also pyrolysis is studied, in nitrogen atmosphere, and gasification in the presence of air, oxygen and different amounts of steam. A detailed discussion on formation and destruction of tars is done. Furthermore, the effect of the heating rate in the decomposition and the residence time of the evolved gases are discussed. Syngas with ratio H 2 /CO from 0.3 to ca. 3 can be obtained from this interesting material. Marine species (microalgae) are usually studied with the aim of cultivate them for gas or oil production, but in this paper we draw attention to the possibility of using a natural resource with a very small impact in the ecosystem.

No abstract