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The aim of this work was investigate the kinetics of the thermal decomposition reaction of sugarcane straw. The thermal decomposition experiments were conducted at four heating rates (1.25, 2.5, 5 and 10°C/min) in a thermogravimetric analyzer using nitrogen as inert atmosphere. The kinetic analysis was carried out applying the isoconversional method of Friedman, and the activation energies obtained varied from 154.1kJ/mol to 177.8kJ/mol. The reaction model was determined through master plots, corresponding to a two-dimensional diffusion. The pre-exponential factor of 1.82*10(9)s(-1) was determined by linearization of the conversion rate equation as a function of the inverse of absolute temperature, concerning to activation energy of 149.7kJ/mol, which are in the order of magnitude for biomass thermal decomposition reported in literature. Finally, the theoretical and experimental conversion data showed a very good agreement, indicating that these results could be used for future process modeling involving sugarcane straw.

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The study of fluid dynamic and mixing characteristics of biomass particles in fluidized beds is fundamental for comprehension of thermal conversion processes. In this chapter a review of literature showed a large lacks of technical information about the quality of fluidization and representative models concerning binary mixtures (biomass and inert). A case study was presented involving Eucalyptus grandis wood and tucumã endocarp in order to obtain fluid dynamic parameters such as the characteristic fluidization, velocity and porosity, and the bed expansion. These parameters were more significant for mixtures with smaller diameter and mass fraction ratios, and sphericity ratio, due to the facility of beds to fluidize. A map was presented to identify the limits of effective mixtures considering four classes as a function of the complete fluidization Reynolds' and Archimedes' numbers. Empirical correlations have been proposed and showed a good agreement with the experimental work.

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