Transferencia de massa gas-liquido em leitos centrifugos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

The development of high performance equipment is nowadays one of the most important preoccupations in chemical engineering research and design. The target is to devise techniques to obtain low dimension equipment and to intensify separation efficiency, generating compact and efficient plants. Gas-liquid contact systems as absorption and distillation, normally require large columns to obtain high separation degrees. In these columns the gravity is the driving force for the flowing and contact of the two phases. Literature reports that rotating packed beds present high efficiency with reduced dimension as compared to the conventional packed bed. The high rotating velocity provides a strong centrifugal field permitting the use of high rates of liquid and gas. The purpose of this work is to evaluated the hydrodynamic and mass transfer behaviour of a rotating packed bed studying the stripping of acetone of an acetone-water solution by air. The bed was operated at 500 - 5000 rpm. The contact between the two faces occurs in the packed bed contained in a rotor with 10,5 em outer diameter and 4,0 cm inner diameter being 3,0 em high. Liquid flows from the inner edge to the outer edge of the rotor due to the centrifugal force. Gas flows inward from the outer edge to the inner edge countercurrently to the liquid. The hydrodynamic behaviour of the equipment was studied using water-air, to obtain the region of stable operation, where liquid entrainment is absent. Air flow ranged from 10 to 80 l/min, and liquid ranged from 0,5 to 2,0 l/min and rotor velocity in the ranged from 500 - 5000 rpm. Mass transfer experiments, using aqueous solutions of acetone (1,5 %) and air, were performed operating the equipment with rotation velocity and rates in the stable region. Experimental values of Kga were determined and the results show that the mass transfer coefficient is dependent on the gas and liquid flow rates and rotation velocity, and their values are 2 to 5 times higher than those calculated for an equivalent conventional packed bed. An empirical equation was fitted to correlate the mass transfer experimental coefficients for rotating packed bed. The system presented high separation efficiency in a reduced size equipment

ASSUNTO(S)

separação (tecnologia) massa - transferencia

ACESSO AO ARTIGO

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