Studies On Initial Liquid Distribution And Performance Of Rotating Jet Bed

Using centrifugal force to intensify mass transfer, a rotating packed bed (also called HIGEE or RPB), is a new type of high-efficiency equipment developed in the early eighties of twentith cenrtury. RPB has been widely applied in absorption, stripping, distillation, extraction process of chemical industry, pharmacy industry and light industry.Rotating Jet Bed is a new type of HIGEE which key components are the initial liquid distributor rotating with Jet Bed and the rotor with concentric rings. And there are two types of initial liquid distributors, disc type and coil pipe type respectively .For the liquid distributor of disc type, the input liquid is thrown with high speed by the rotating disc, which achieves a good initial liquid distribution. The liquid distributor of coil pipe type is composed of several coil pipes arranged uniformly along the rotating shaft of Rotating Jet Bed. The liquid sprays from the small holes on the outer edge of the coil pipes for a good initial liquid distribution. The rotor is composed of several concentric rings about the rotating shaft. The surfaces of the concentric rings are plentiful of perforations through which both gas and liquid flow countercurrently, contacting intimately. And the mass-transfer and heat-transfer of gas-liquid takes place. The coil pipe type liquid distributor is suggested, for the disc type liquid distributor resists the gas flow. The hydralic and mass-transfer performance of the Rotating Jet Bed with coil-pipe liquid distributor was investigated. With the coil pipe type liquid distributor, the experiments of cold and hot models were carried out in the Rotating Jet Bed with the rotor of 45mm height and 260mm diameter, and the rotor was with packing and without packing. The gas pressure drops was investigated in the cold model experiments with air-water. And the performance of mass-transfer was investigated in the hot model experiments with ethanol-water under total reflux.The experimental results show that:(1) The liquid distribution coefficient of the liquid distributors of disc type increases with the increase of liquid rate and rotational speed. The static liquid distribution is better than the rotating liquid distribution, because the coefficient of static liquid distribution is smaller than that of rotating liquid distribution.(2) The gas pressure drop of Rotating Jet Bed with the liquid distributor of coil pipe type increases with the increase of the gas kinetic energy factor and the supergravity factor. And the gas pressure drop of Rotating Jet Bed without packing is lower than that with packing.(3) The gas pressure drop of Rotating Jet Bed with packing decreases sharply when the liquid spray density increases from zero,which is similar to the unusual behavior that the gas pressure drop reduces sharply where the liquid enter the RPBS. And the gas pressure drop keeps constant when the liquid spray density increases to a certain value. The gas pressure drop of Rotating Jet Bed without packing keeps constant when the liquid spray density increases from zero. And the gas pressure drop increases slowly when the liquid spray density increases to a certain value.(4) On the total reflux, the mass-transfer efficiency increases with the increase of the quantity of reflux and rotational speed. The theoretical plates per meter ranges from 20 to 54. The highest mass-transfer efficiency of 54.31 theoretical plates per meter can be achieved when the rotational speed is 1000r/min for Rotating Jet Bed without packing.(5) The gas pressure drop of Rotating Jet Bed without packing is lower 10% than that with packing. And the number of theoretical plates per meter of Rotating Jet Bed without packing is higher 8.6% than that with packing. Therefore, the comprehensive performance of the Rotating Jet Bed without packing is superior to the Rotating Jet Bed with packing.