Study On Application Mechanism Of A New Type Efficient Symmetrical-flow Packed Tower

In order to deal with the "wall flow effect" and the "scaling effect" that commonly exist in packed tower, the cell-grid of a new type efficient Symmetrical-flow Packed Tower was developed. The Common packed tower was improved by the combining form of the cell-grid. The Symmetrical-flow Packed Tower was studied comparatively with the Common Packed Tower by experiments and numerical simulation.The experiments using air-water-CO2 as working substance were operated in a cold-model experimental packed tower to research the pressure drop, wall-flow and mass-transfer efficiency of the Symmetrical-flow Packed Tower and the Common Packed Tower. Under the same working condition, the experimental results showed that, comparing with the Common Packed Tower, the dry packing pressure drop per meter of the Symmetrical-flow Packed Tower decreased by about 14.43% in average;under four different spray densities, the pressure drop of the Symmetrical-flow Packed Tower decreased by about 5.71%,2.48%,3.47%,5.55% in average;wall-flow reduced by about 4.99%,5.64%,23.69%, 7.96% in average; comparing with the Common Packed Tower, the unit height of transfer of the Symmetrical-flow Packed Tower decreased approximately by 31.52%,27.88%,23.76%, 19.12% in average. The experimental results indicated that wall-flow and mass-transfer efficiency of the Symmetrical-flow Packed Tower were obviously better than the Common Packed Tower when the pressure drop was not increased.According to introduce the theory of Porous Media and the definition of Representative Elementary Unit (REU), the volume averaging technique was applied to derive the CFD mathematical model of the packed tower under one-phase and two-phase flow conditions. And the Computational Fluid Dynamics software (FLUENT6.2) was used to solve the model equations which were built above. Meanwhile, the three-dimensional CFD models of both two packed tower were drawn as a physical model in the simulation. The Porous Media Model and Eulerian Multiphase Flow Model of FLUENT6.2 were chosen to simulate the gas-phase flow and the gas-liquid flow. Under the same simulational condition, the results such as pressure contours, wall-flow contours and velocity contours were presented. The simulational results showed that the wall-flow of the Symmetrical-flow Packed Tower reduced by about 31% comparing with the Common Packed Tower; according to the velocity contours of the same cross-section height, the velocity distribution of the Symmetrical-flow Packed Tower was more uniform than that of the Common Packed Tower. The simulational results were fit well with the results of the experiments, and the average deviation of the dry and wet packing pressure drop between the numerical simulation and the experiments were about 15.5% and 10.3%.The study results showed that the Symmetrical-flow Packed Tower can be effectively reduced the "wall-flow effect" and eliminated the "scaling effect", and also increased the mass transfer efficiency of the packed tower. It will provide a strong reference for industrial application of packed tower.