In a previous paper, pressure drop, flooding and mass-transfer characteristics of a novel pilot-scale distillation column called spinning cone column (SCC) were presented. Here, we present the result of comparison of mass-transfer efficiencies of SCC and structured packing. Comparison of SCC and structured packing mass-transfer characteristics show that the gas and liquid-side height of transfer units (HTUs) of the SCC are on the average 20% and 50% lower than the corresponding values for structured packing respectively. This in turn results in lower HETPs of the SCC for practical applications. Predicted HETPs in ethanol distillation using SCC are 30% lower than those of structured packing. Predicted HETPs for fusel oil and orange oil distillations are also 45% and 35% lower respectively than the experimental values obtained for structured packing. From these results, it is concluded that SCCs are more efficient with respect to mass-transfer than this particular structured packing, but to draw a general conclusion, more specific data on pressure drop per NTS, and liquid hold-up and residence time of the two columns should be available.

Mass transfer coefficients of rising drops in spray and packed columns with randomand structured packing in a liquid-liquid extraction operation were experimentallymeasured and the results compared. In this work, a high interfacial tension chemicalsystem of toluene-acetic acid-water in a structured packed column is investigated.Results of random and structured packing show that random types are effective only fora drop size less than 9 mm, while the structured ones are shown to have a positive effecton mass transfer coefficient in a wide drop size range. Furthermore, structured packingproved to be slightly more effective than random packing in improving the masstransfer coefficient. The effect of drop size on mass transfer coefficient has also beenstudied in this work and the results showed that when the drop diameter increases, themass transfer coefficient increases too. Finally, new correlations for the prediction ofthe mass transfer coefficient in both a random and structured packed column have beenintroduced which are in better agreement with the experimental data in comparisonwith those resulted from Newman, Kronig-Brink and Handlos-Baron models.

The effects of meshing type and turbulency model on distribution and volume fraction of the liquid phase on the MontzpakB1-250Y structured packing at steady state condition was investigated employing computational fluid dynamics (CFD) technique. The volume of fluid method was used to simulate the liquid distribution, while different meshing types (e.g. tetrahedron and cooper algorithm) and turbulency models (including Standard, RNG and Realizable) were used for modelling the system. Resulted equations were numerically solved employing the finite volume method. Liquid maldistribution was studied using parameter and volume fraction of the liquid phase at various velocities and conditions. The results were compared with experimental data reported in the literature indicating that a proper selection of meshing type and turbulency model can significantly affect hydrodynamics simulation of the structured packing.

World war period witenessed a boom in styrene demand due to its application in the manufacture of synthetic rubber. This led to a dramatic increase in styrene capacity. Since then demand and capacity have grown continuously. There is various Technologies for Styrene monomer production. ABB-lummus/Uop, Epi Europa and Shaw stone&Webster badger Technologies are samples of them. These Technologies used of Ethylbenzene dehydrogenation method. Ethylbenzene hydroperoxidation is other Technology. Present investigation discusses first type (Ethylbenzene dehydrogenation methods). Then various packing types used in Styrene monomer/Ethylbenzene separation, is discussed. Today, more than 70% of the world capacity for styrene monomer distillation have been equipped by Mellapak structured packings. Maxpak, Sulzer BX and Intalox structured packing are in the next grades.

In structured packings, the pressure drop is one of the critical factors in calculating the optimal diameter of the tower. In the present research, two phase pressure drop in SulzerBX structured packing was optaincd by computational fluid dynamics and compared with experimental data. The relative error was 9.1%. Furthermore, the amount of maximum pressure drop was 833.7 Pascal per meter at gas and liquid velocities of 0.899 and 0.0298 m/s, respectively. In addition, the minimum pressure drop was 25.1 Pascal per meter at gas and liquid velocities of 0.341 and 0.0298, respectively. Compared with conventional packings the pressure drop in perforated plates illustrated a 7% reduction. This study aims to investigate the influence of packing plates holes on two phase pressure drop.

In this study, Computational Fluid Dynamics (CFD) has been used to determine the dry pressure drop, wet pressure drop and Liquid holdup in four types of structured Packings (Mellapak 250Y, Mellapak 250X, Flexipak 1Y and Gempak 1A). By predicting the dry pressure drop and liquid hold up, the two-phase pressure drop can be easily calculated from the correlations. The results show that the liquid film thickness in the Mellapak 250Y, Flexipak 1Y, Gempak 1A and Mellapak 250X are 0.324, 0.34 and 0.3232 mm in the preloading region, respectively. The liquid hold up in the Mellapak 250Y, Flexipak 1Y, Gempak 1A and Mellapak 250X are 7.62%, 4.24%, 3.77% and 7.55% in the preloading region, respectively. In general the predictions agree well with the experimental data, indicating the suitability of the proposed models for the simulation of the hydrodynamics and mass transfer in structured packed columns.

Packed towers are continuous contact systems in which unlike tray towers, the liquid phase is dispersed, and the gas phase is continuous. Packed or packed distillation towers are widely used in chemical industries. The use of such towers is preferable to tray towers, especially in vacuum distillation operations. These columns are suitable in low pressure-drop or low liquid hold up operations. In this study, the pressure drop for the air-water system was simulated, and presented by a 3D model consisting of two layers of Gempak 2A structured packings by using computational fluid dynamics. Computational Fluid Dynamics is a useful tool for scale-up, design and optimization of chemical engineering equipment for its detailed prediction of hydrodynamic characteristics. The BSL turbulence model was used for simulation. The total number of meshes were 1315200. The simulation results were compared with laboratory and existing experimental data. The simulation error of the two-phase pressure drop compared with experimental data was 16.6%. The results of prediction agree well with the experimental data indicating the suitability of the proposed method for the simulation of the hydrodynamics in structured packed columns. The results of this study can be used in the hydraulic design of packed towers containing structured packings.

The design and operation of pilot columns have long been considered as a prerequisite for the design of industrial-scale processes. Despite the obvious benefits, a few reactive distillation pilot plants have been set up. Researches have been shown that reactions such as esterification, transesterification, etherification, alkylation, dehumidification, acetylation and isomerization are best suited in reactive distillation columns. In general, the adaptation of the optimal temperature zone for the chemical reaction is the key parameter in designing reactive distillation columns. On the other hand, one of the most important preconditions for the implementation of these processes is the study of reactive azeotrope points. The diameter of the pilot columns used in most studies is 50 mm and the height of the columns varies according to the type of the process. Sulzer catalytic structured packing has been used mostly in these columns.

Type of packings and characteristics of their geometry can affect the flow behavior in the reactive distillation columns. KATAPAK SP is one the newest modular catalytic structured packings (MCSP) that has been used in the reactive distillation columns, recently. However, there is not any study on the hydrodynamics of this packing by using computational fluid dynamics. In the present work, a 3D VOF model was developed to evaluate dry and wet pressure drops of catalytic structured packings, MCSP-11 and 12. The module of MCSP is made of alternating vertical layers of structured packing sheets (Mellapak Plus) and catalyst bags. The goal of this paper is to illustrate the effect of geometry on the hydrodynamics and characterization of flow in the MCSP modules. Results showed that the mean relative errors for prediction of dry and wet pressure drops were 17% and 7% for MCSP-11 and 11% and 12% for MCSP-12, respectively. According to CFD results, pressure drop in closed channels was higher than that in open channels. The catalyst bags were simulated as porous media. The simulation led to determination of the liquid velocity distribution in the catalyst bags.