Studies On Gas Pressure Drop And Mass Transfer Performance In A Novel Mulit-Liquid-Inlet Rotating Packed Bed

Rotating packed bed (RPB) is recognized as a novel efficient and energy saving gas-liquid contactor. The rotating rotor with a high speed in the RPB creates a significant centrifugal field which can be used to simulate a high gravity environment. In this field, liquid is cut into smaller droplets by the centrifugal force, which results in large gas-liquid contacting area. At the same time, mass transfer efficiency in the RPB could be intensified. So far, RPB has been widely used in a variety of applications in chemical separation processes and has great prospects for development.A significant phenomenon in a RPB is the so called end effect which occurs in the part of the packing close to the inner edge of the rotor. The mass transfer accomplished in this end zone can indeed be a multiple of what is achieved in the rest of the rotor. A novel multi-liquid-inlet rotating packed bed (MLI-RPB) was developed based on the concept of end effect. MLI-RPB has an annular rotor and uses multi-liquid-inlet to create more end zones. The gas pressure drop and mass transfer efficiency of the RPB are two important parameters. Because of the novel rotor structure of MLI-RPB, the gas pressure drop and mass transfer efficiency of MLI-RPB may be different from the traditional RPB. Therefore, this work studied effects of rotational speed, gas flow rate, and liquid flow rate on the pressure drop and mass transfer efficiency of MLI-RPB. Meanwhile, the comparison of pressure drop and mass transfer efficiency between the MLI-RPB and traditional RPB which had a same rotor size as the MLI-RPB was investigated. The results showed that the pressure drop increased with an increasing rotational speed, gas flow rate, and liquid flow rate. The mass transfer efficiency increased with an increasing of gas flow rate and liquid flow rate. However, the mass transfer efficiency of MLI-RPB increased with an increasing rotational speed. When the rotational speed continued to increase, the mass transfer efficiency of MLI-RPB began to decrease. The gas pressure drop and mass transfer experiments in a traditional RPB with the same rotor size as the MLI-RPB were also conducted. The results showed that the MLI-RPB had smaller pressure drop but higher mass transfer efficiency than the traditional RPB. In addition, based on the experimental data under different conditions, correlations were proposed to predict pressure drop of the MLI-RPB by the multiple linear regression method. Based on the surface renewable theory, a model was also developed to calculate mass transfer coefficient(kLa). The calculated results of mass transfer coefficient (kLa) agreed with the experimental results very well and the error was within15%.