Avaliação de parâmetros globais de desempenho de biorreatores pneumáticos através de fluidodinâmica computacional
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Data
2015-03-25Autor
Rodriguez, Guilherme Youssef
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Pneumatic bioreactors are devices free of moving parts which have the purpose
of converting raw materials in bio-products of commercial interest by the action of enzymes
or cells. They are promising in the biochemical industry, ensuring good oxygen transfer and
consuming less energy. Global performance parameters such as global gas hold up and the
volumetric oxygen transfer coefficient are important criteria in the design and selection
among different geometries of the mentioned devices. In the present work it was carried out
modeling and simulation of pneumatic bioreactors based on Computational Fluid Dynamics
(CFD) in order to estimate the global gas hold up and the volumetric oxygen transfer
coefficient in three different geometries of pneumatic bioreactors: bubble column, concentric tube airlift and split tube airlift. The simulated results of each performance parameter were verified by comparison with the experimental values reported by Thomasi et al. (2010) and Mendes and Badino (2015) for the fluids distilled water, glycerol solution 10 cP and xanthan gum solution 0.2% w/v (weight/volume) in a wide range of specific air flow rate (0 to 5 min- 1). Application suite ANSYS® 14.5 was used for numerical simulations in CFD. Important parameters such as the bubble diameter played a great influence on results of the volumetric oxygen transfer coefficient. It can be observed by the experimental and simulated results that the concentric tube airlift bioreactor was the best alternative to the global gas hold up and the volumetric oxygen transfer coefficient (reaching 14% and 0.06 s-1 for distilled water, respectively). It was found that the results obtained via the CFD agreed with the majority trend of experimental data, capturing the most important hydrodynamic phenomena and mass transfer characteristics, showing that the modeling of different systems with different fluids fulfilled the main objective of obtaining reliable models design and performance of other geometries of pneumatic bioreactors.