Mass Teansfer Performance Of A Rotating Packed Bed With Nickel Foam Packing

As one of the breakthrough technology to strengthen the process, gravity technology has been applied widely to industrial applications. Rotating packed bed is the core equipment and packing is an important part of the rotating packed bed, whith is the main place mixing and mass transfer occurred. Selection the type and structure optimization of packing is one of the main measures to improve the mass transfer efficiency. More attention are paied on the optimizing internal components to improve the energy efficiency of rotating packed bed. Therefore, study on mass transfer performance of rotating packed bed with new packing is of great significance.This work modified hydrophobicly the nickel foam packing and charactered. The mass transfer efficiency of the rotating packed bed with modified and non-modified nickel foam packing were examined. Based on the experiments, empirical correlations on parameters were proposed. Moreover, the possible mechanism for the enhancement of the mass transfer in the rotating packed bed with modified nickel foam packing was also explored by a flow visualization method. The main findings are listed below:(1) After the modification of nickel foam packing, the contact angle of the packing is increased by 25°. It can be seen that spheres covered with micro-nano-level "petal-like" three-dimensional structure were formatted in the surface of the packing by scanning electron microscope photograph. Those microstructures may play a significant role on the hydrophobic properties of the packing. The effective interfacial area and the volumetric liquid-side mass teansfer coefficient increase with rotational speed, liquid flow rate and gas flow rate. The volumetric liquid-side mass teansfer coefficient values of the rotating packed bed with modified packing were averagely 28% higher than those of the rotating packed bed with non-modified packing. The volumetric gas-side mass teansfer coefficient increases with rotational speed, liquid flow rate and gas flow rate. The volumetric gas-side mass teansfer coefficient values of the rotating packed bed with modified packing were averagely 7% higher than those of the rotating packed bed with non-modified packing. The rotating packed bed with modified nickel foam packing shows better performance for the liquid-controlled mass transfer, compared to the rotating packed bed with non-modified nickel foam packing.(3) In order to explore the explaination of the mass transfer enhancement, liquid dispersion of modified nickel foam packing and non-modified nickel foam packing were studied with a platform. The static visualization showed that the average diameter of the droplets from the modified nickel foam packing was about 20% smaller than that from the non-modified nickel foam packing, while it is only about 13% when the packing is dynamic. Visualization studies suggest that the average diameter of the droplets decreases when the thickness of the packing and rotational speed increase, while it increases with the liquid flow rate.