Aspectos fluidodinâmicos de misturas binárias de resíduo de tabaco e areia em leito fluidizado

Content Provider	Semantic Scholar
Author	Oliveira, Tiago José Pires De
Copyright Year	2012
Abstract	Currently seeking new forms to meet the world's ene rgy needs and biomass is an alternative to supply as a source of renewable ener gy and cleaner. The fluidized bed reactors are widely used for the production of fuel gas, syn gas and products such as methanol, bio-oil, etc. Due to its good gas-solid contact, high rates of heat and mass transfer, the beds fludizeds options has become effective for the realization of fast pyrolysis because they favor the physical and chemical processes that occur during p yrolysis. In the fast pyrolysis of biomass in bubbling fluidized bed, the sand is used to ensu re homogeneity of mixing and high heat transfer coefficients. These characteristics are fu ndamental to the kinetics of thermal decomposition of biomass. The fluidization of mixtu res of sand and biomass is characterized by particles of different shapes, sizes, densities and compositions (amount of each solid). Therefore this work was to study the fluid-dynamic behavior of the fluid and particles within the bed, and the main objective to determine the mi nimum fluidization velocities of binary mixtures of biomass and inert. We investigated the fluid dynamics of mixtures of particles fluidized in order to determine an initial composit ion which mitigates the segregation effect. The segregation is characterized by the difference of the terminal velocity of the particles that make up the mixture, a fact that may occur due to t he difference of densities and particle sizes. Therefore, experiments with mixtures of biom ass and inert were conducted by varying the composition of biomass and the main fluid dynam ic information were measured. The materials used were the work of the stalk of tobacc o dust and sand Brazilian standard normal (IPT). Regarding the parameters studied in the flui d dynamics of mixtures, the experiments allowed a better understanding of the mechanisms of egregation. Overall, in all mixtures used in the experiments we observed a concentration of inert along the bottom, whereas the biomass, less dense, concentrated mainly at the top of the annular region. As for the percentage by weight of biomass, which in the exper iments were 5, 10 and 15%, it was observed that for mixtures with 15% of biomass is t he formation of preferential channels, packing the bed and the presence of bubbles. The mi nimum fluidization velocities of these binary mixtures were obtained experimentally and th e values were compared with some correlations reported in the literature.
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Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article