TV column packaging design analysis

Nowadays, as the increasing marketization of dissemination medium, the competition between the dissemination medium gets hot up. The social television has now entered a new period in which the central task is to compete. ＂Brand＂ ＂marketing strategies becomes more important. Brand columns are important. It is to the television channel what product to enterprise. Famous-brand column brings famous-brand column and social benefit. As well as building and maintaining a good brand column needs high quality program content and high standard program form. As well as exquisite column decoration, thereby, TV column packaging became essential.

Three-dimensional Computational Fluid Dynamics Modeling of Two-phase Flow in a Structured Packing Column

Characterizing the complex two-phase hydrodynamics in structured packed columns requires a power- ful modeling tool. The traditional two-dimensional model exhibits limitations when one attempts to model the de- tailed two-phase flow inside the columns. The present paper presents a three-dimensional computational fluid dy- namics （CFD） model to simulate the two-phase flow in a representative unit of the column. The unit consists of an CFD calculations on column packed with Flexipak 1Y were implemented within the volume of fluid （VOF） mathe- matical framework. The CFD model was validated by comparing the calculated thickness of liquid film with the available experimental data. Special attention was given to quantitative analysis of the effects of gravity on the hy- drodynamics. Fluctuations in the liquid mass flow rate and the calculated pressure drop loss were found to be quali- tatively in agreement with the experimental observations.

Removal of high concentration CO_2 from natural gas at elevated pressure via absorption process in packed column

Carbon dioxide （CO2） removal is an essential step in natural gas （NG） processing to provide high quality gas stream products and minimize operational difficulties. This preliminary study alms to investigate the removal of CO2 at high concentration level from the mixture of CO2-NG gas stream at elevated pressure via absorption process. This is to explore the possibility of exploring high CO2 content natural gas reserves by treatment at offshore platform. A mixed amine solvent, Stonvent-II, was used for the absorption of approximately 75 vol% CO2 in CO2-NG stream at a pressure of 10 barg. The initial solvent temperature was varied in order to study the impact of initial temperature on the absorption performance. Preliminary study at temperatures of 35 ℃ and 45 ℃ indicates that Stonvent-II was able to perform almost 100% removal of CO2 under both conditions. However, the CO2 absorption effect took place faster when the initial liquid temperature was lower. This is because when the initial liquid temperature is high, the temperature increase in the packing bed caused by the reaction heat is high which impacts the efficiency of absorption negatively.

CFD Analysis of Gas Distributor in Packed Column ——Prediction of Gas Flow and Effect of Tower Internals Geometry Structure

Computational fluid dynamics (CFD) simulations were carried out on the gas flow patterns of twin-tangential annular deflector gas distributor in the absence of liquid flow in a packed column (6.4 m in diameter), and the gas flow field in the column was presented close to reality on the whole. Furthermore, after ame-(lioration) of this gas distributor frame, turbulence energy and turbulence energy dissipation rate were both decreased greatly.Simulation results showed that the flow pattern and the distribution of gas flow were strongly affected by the column bottom frame; the proper column bottom frame could decrease the flow pressure drop greatly. Multifold factors, such as the column bottom geometry structure and distributor structure which affects the distribution capacity, must be considered.

Extraction of Caprolactam from Aqueous Ammonium Sulfate Solution in Pulsed Packed Column Using 250Y Mellapak Packings

Liquid-liquid equilibrium (LLE) data of water-caprolactam-benzene-(NH4)2SO4 system at 303 K were measured for extraction of caprolactam from aqueous ammonium sulfate solution. The influence of fluid flow rate, pulsation intensity on flooding velocity and mass transfer was studied for extraction of caprolactam from ammonium sulfate solution in a laboratory pulsed packed column. The flooding velocities and overall apparent height of a transfer unit were given under various operation conditions. An industrial column developed based on above study is operated well. The scale-up effect is discussed.

Measurement of Mass Transfer Coefficients and Their Modelling of Continuous Counter-Current Aqueous Two-Phase System in a Packed Extraction Column

Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.

Simulation of MEG Packed Distillation Column Using an Equilibrium Stage Model-Case Study on Operating Parameters of Farsa Petrochemical Company： Assaluyeh-lran

Two types of equilibrium and non-equilibrium stage models are generally used to simulate the mass transfer of packed distillation column. Using non-equilibrium model requires the calculation of mass transfer coefficients, thus, usually equilibrium-based methods are preferred to be used for simulations of distillation columns. In this paper, packed column distillation of production of Mono Ethylene Glycol in FARSA SHIMI Company （Assaluyeh-Iran）＇s Ethylene Glycol portion has been simulated through using the equilibrium model and solving the related equations. The simulation has been carried out in the MATLAB environment. The column also has been simulated in the Aspen Hysys and Aspen Plus ver. 2006.5 environments. Then, the output has been compared with software results, designing and operating data of the underlying columns which demonstrate good consistency with the model. Having the model validated, the effect of some operating parameters has been analyzed through the model.

EXAMINATION OF THE SURFACE FREE ENERGY AND ACID-BASE PROPERTIES OF CELLULOSE BY THE COLUMN WICKING TECHNIQUE AND THE CRITICAL PACKING HEIGHT/DENSITY

The column wicking technique was applied to estimate the surface free energy of cellulose, the importance of which is to obtain a real effective capillary radius, Reff, initially from the plot of Washburn penetration distance versus time. Since the cellulose sample could not be packed with good reproducibility, therefore, Reff can not be obtained readily from the slope of the plot. A method was developed in this paper by uniting all apparent packing heights with a unique value to deduce a real effective capillary radius. Based on the defined critical packing height related to the critical packing density, the surface free energy and acid-base properties of cellulose Sigma C8002 were estimated.

Novel predictive tool for accurate estimation of packed column size

Traditionally the majority of fractionation columns in natural gas processing plants were equipped with trays.However an option to trayed columns is to use packing.Packed columns offer a larger surface area per unit volume for mass transfer and the continuous gas to liquid contact throughout the column rather than at specific levels （such as in tray columns）.For process design purposes,it is essential to estimate the pressure drop for enabling the proper operation of packed columns.In this study,a simple generalized pressure drop correlation （GPDC） which is easier than existing approaches requiring more complicated and longer computations is developed for sizing randomly packed fractionation columns for pressure drops up to 150 mm water per meter of packing.This correlation can be used to estimate pressure drop for a given loading and column diameter.Alternatively,for a given pressure drop the diameter can be determined.The predictions from the proposed correlation have been compared with reported data and found good agreement with average absolute deviation hovering around 4.9%.The proposed predictive tool is superior owing to its accuracy and clear numerical background,wherein the relevant coefficients can be retuned quickly if new and more accurate data are available in the future.This proposed simple-to-use approach can be of immense practical value for the engineers and scientists to have a quick check on the pressure drop in packed columns for a given loading and column diameter.In particular,gas engineers would find the proposed approach can be used very friendly involving no complex expressions with transparent and easy-to-handle calculation steps.

Pressure drop of structured packing in pilot column and comparison to common correlations

Packed columns are widely used in the chemical industry such as absorption,stripping,distillation,and extraction in the production of e.g.organic chemicals,and pharmaceuticals.Pressure loss and pressure drop correlations are of special interest when it comes to the hydrodynamic properties of a column.The pressure loss across the column is of interest in the design phase when the size of the blower to drive the gas stream through the column has to be decided.The loading point and flooding point are also influenced by the pressure loss and the area of operation is determined from these points.This work examines four different correlations on pressure drop.The correlations are(i)Ergun’s equation(1952),(ii)an improved version of Ergun’s equation by Stichlmair,Bravo,and Fair(1989),(iii)an equation developed by Billet and Schultes(1999),and(iv)an equation by Rocha,Bravo,and Fair(1993).The complexity of the correlations is increasing in the mentioned order,Ergun’s equation being the simplest one.This study investigates if the more complicated correlations give better predictions to pressure drop in packed columns.This is determined by comparing the correlations to experimental data for pressure drop in a packed column with 8.2 m of structured packing using water as the liquid and atmospheric air as the gas.Seven experiments were carried out for determining the pressure drop in the column with liquid flows varying from 0 to 500 kg·h^(-1).At constant liquid flow,the gas flow was varied from approximately 10 to 70 kg·h^(-1).The pressure drop across the non-wetted column was best described by the correlation by Rocha et al.while the pressure drop for liquid flows from 100 to 500 kg·h^(-1)was,in general,best described by Stichlmair’s equation.For an irrigated column,the highest deviation was a predicted pressure drop 69.6%lower than measured.The best prediction was 0.1%higher than the measured.This study shows,surprisingly,that for a system of water and atmospheric air,complicated correlations on pressure drop determination do not provide better estimates than simple equations.

HYDRODYNAMICS AND MASS TRANSFER IN A NEW TYPE(FG)STACK PACKED EXTRACTION COLUMN

Hydrodynamics and mass transfer experiments were carried out in a 0.1m diameter extraction column with a new type (FG) stack packing developed recently in our laboratory.The working systems used were n-Butano1/Succinic acid/water with low interfacial tension of 1.50×10-3N·m-1 and 30% TBP (Kerosene)/Acetic acid/water with interfacial tension of 10.0×10-3N· m-1. Experimental results obtained indicated that (FG) stack packed extraction column was proved to possess high throughput capacity and excellent mass transfer efficiency. Replacing rotary discs with FG packings in a lube furfural extraction tower was quite success with significant economical benefits being claimed.

CONTRIBUTION TO PACKED COLUMNS SCALE-UP IN SEPARATION PROCESSES

Correlations will be presented to describe liquid hold up, loading and flooding capacity, volumetric mass transfer coefficients on liquid and gas or vapour phase and the pressure drop as a basis for computing packed columns, dumped and regular as well, including the influence of end effects on scaling. The relationships are found on a sound physical and mathematical basis and their validity were confirmed by experimental investigations of many packings; some of them were selected to be considered in this work.

Flow of gas-liquid-solid system and its application in packed flotation column

A packed flotation column, which is packed with multiple board ripple packings, was described. Based on comprehensive steady state models, chemical reactor developed previously in chemical engineering subjects, have been extended to packed flotation column for mineral separation. The experimental results verify that tanks in series model is better than axially dispersed plug flow model to describe flow pattern in the collection zone of column by RTD (residence time distribution), and the error of experimental data and calculated data of both models are 0.07% ～ 0.1% and 0.18% ～ 0.45% respectively. And, RTD of gas phase was also considered, results also show that gas in the whole column appears plug flow. The cleaning process through adding wash water in froth zone of column was described, and the effect of superficial air velocity and superficial wash water velocity on the cleaning action of froth zone were discussed. Flotation experiment for single column was conducted for phosphate ores. The recovery for P 2O 5 was 85.8%, and the grade was 26.8%.

A New Model for the Simulation of Distillation Column

A new computational mass transfer model is proposed for simulating the distillation process by solving the fluctuating mass flux u^＇ic^＇ for the closure of turbulent mass transfer equation in order to obtain the concentration profile and the separation efficiency of distillation column. The feather of the proposed model is to abandon the conventional way of introducing the turbulent mass transfer diffusivity （dispersion coefficient） to the turbulent mass transfer equation. To verify the validity of the proposed model, a commercial scale packed column and a sieve tray column were simulated and compared with published experimental data. The simulated results were satisfactorily confirmed in both concentration distribution and senaration efficiency.

Comparison of Gas Distribution Properties of Conventional and High Capacity Structured Packings

This paper presents the results of an experimental study carried out using large scale equipment to observe the effect of geometry on gas distribution properties of a high capacity corrugated sheet structured packing （Montz-pak B 1-250M） and to compare it with that of its conventional counterpart （Montz-pak B1-250）. Although the high capacity packing exhibits a significantly lower overall pressure drop, the gas distribution performance is similar to that of the conventional packing, and in both cases consistently good one.

Optimizing the Synthesis of Ethyl tert-Butyl Ether in Continuous Catalytic Distillation Column Using New Ion Exchange Resin Catalyst

Liquid phase synthesis of one of the important fuel oxygenate, ethyl tert-butyl ether （ETBE）, from etha-nol and tert-butyl alcohol （TBA） has been studied in catalytic distillation column （CDC） using ion exchange resin catalyst CT-145H. A packed CDC of 1.2 m height and 50 mm diameter with indigenously developed reactive sec-tion packing was used to generate experimental data. Effect of different key variables on product purity in distillate, was investigated to find the optimum operating conditions for ETBE synthesis. The optimum conditions for 0.2 kg·s-1 of ethanol feed were found：reboiler duty of 375 W, molar feed ratio of 1︰1.3 of reactants, and reflux ratio of 7. Concentration profiles for each component along each column section at optimum conditions were also drawn. Neither output nor input multiplicity was observed at experimental conditions.

Experimental Investigation of Pressure Drop Hysteresis in a Cocurrent Gas-Liquid Upflow Packed Bed

Extensive experimental work on hysteresis in a c℃urrent gas-liquid upflow packed bed was carried out with three kinds of packings and the air-water system. However, only when packed with small glass beads ((1.4 mm) was the bed pressure drop hysteresis observed. Two more liquids with different liquid properties were employed to further examine the influence of parameters on pressure drop hysteresis. The similarity of pressure drop hysteresis in packed beds was concluded in combination of experimental evidence reported in literature.

An Approach to the Estimation of the Packing Efficiency by Considering Gas and Liquid Axial Mixings

To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operation has been proposed based on the mixing pool model. The mass transfer and hydrodynamic data of structured packing, Mellapak 350Y, obtained in a high pressure tower have been used to test the validity of the proposed model. Compared with the SRP model and the Gualito model, it is found that for high pressure distillation process the present mathematical prediction shows a mean relative error of about 10% to the experimental data,the accuracy of which is the same as that by the Gualito model but better than that by the SRP model.