Studies On The Gas Pressure Drop Characteristics Of Multilevel Cross-flow Rotating Packed Bed

The cross-flow rotating packed bed has been widely used in gas absorption, stripping,dust and other unit processes, due to its lots of advantages such as large gas capacity, lowpressure drop, high liquid mass transfer coefficient, small size and provincial investment,which is known as the “electronic transistor” in the chemical industry. But the existingstructures of cross-flow rotating packed bed are not obvious to strengthen the gas phase massprocess, thus it is not suitable to gas-liquid membrane, particularly gas film controlled masstransfer process. Therefore, the multi-stage cross-flow packed bed has been used, the originalsingle-filler was instead by three fillers, namely rotating the upper and lower layers andfixing the middle layer in order to perform a strong airflow disturbance, to strengthen the gasphase mass transfer process.Gas pressure drop of rotating packed bed is directly related to the size of the gastransport energy consumption in industrial applications. The current models and experimentalresults on the gas pressure drop of rotating packed bed do not have the versatility, especiallyfor new laboratory cross-flow rotating packed bed. Thus, the structure of packing type andoperating parameters on gas pressure drop was studied in this article in order to optimize thestructure and screening packing, and provided a reference for the industrial design.The plastic pall ring packing and stainless steel corrugated wire packing were selected inthis paper. Using the air-water system, empty bed gas flow rate, high gravity factor, liquidspray density and other operating parameters were investigated. The results showed, the totalpressure drop of wet bed of plastic pall ring decreased first and then increased with theincrease of the high gravity factor and liquid spray density. The wet bed pressure drop of both the upper and lower packing decreased first and then remained stable with the increase of the high gravity factor. With the liquid spray density increasing, the total pressure drop of wet bed and the wet bed pressure drop of each layer increased. The wet bed total pressure drop of corrugated stainless steel wire packing increased with the increase of high gravity factor. The wet bed pressure drop of the upper and lower layers of packing increased with the increase of high gravity factor and liquid spray density. With both of the packing, the total dry bed pressure drop and the pressure drop of layers of dry bed increased with the increase of empty bed gas flow rate and high gravity factor. The pressure drop of wet bed and dry bed of the plastic pall ring were higher than that of the stainless steel corrugated mesh. The wet bed pressure drop of the middle layer of packing increased with the increase of high gravity factor and liquid spray density, which also reflected that the increase of high gravity factor and the existence of liquid could promote the circumferential rate of gas.When the two packing of upper and lower are plastic Bauer ring, followed by replacement of middle layer packing:plastic Bauer ring, stainless steel wire mesh and remove the packing, to study the gas pressure drop of three layers changes. The research shows that:under the same operating conditions, with the conversion of the intermediate layer fillers, the dry bed and the wet bed pressure drop of lower part filler are essentially invariant. The dry bed and the wet bed pressure drop of the middle layer filler are gradually decrease. The dry bed pressure drop of upper packing is gradually increasing,and the wet pressure drop is essentially invariant. This shows that the middle layer of filler can play a role in the elimination of cyclone, and the better filling body resistance, the better effect.According to theoretical analysis and reasonable simplification, the gas pressure drop of multilevel cross-flow rotating packed bed is divided into:gas inlet and outlet resistance, the gas flows through the next three packed bed, the multistage cross-flow rotating packed bed of vapor total pressure drop model is as follows: The model coefficients were fitted by gas pressure drop data obtained with plastic pallring, the results showed that the error was within20%, indicating that the model can betterreflect the experimental results and the predicted values of the gas pressure drop. This canprovide the guidance of improvement of the multilevel cross-flow rotating packed bed andindustrial applications.