scholarly journals Pemodelan perpindahan massa ekstraksi kolom isian dengan distribusi ukuran tetesan

2018 ◽  
Vol 10 (2) ◽  
pp. 81
Author(s):  
Iwan Ridwan
Keyword(s):  
Mass Transfer ◽  
Droplet Size ◽  
Packed Column ◽  
Distribution Model ◽  
Transfer Model ◽  
Glass Ball ◽  
Dispersion Phase ◽  
Raschig Ring ◽  
Droplet Distribution ◽  
Ball Packing

Mass transfer modeling of extraction in a packed bed with droplet size distribution The evaluation of liquid extraction packed column is not able yet to give a satisfying result caused by constant spherical droplet size assumption. Droplet size from dispersion phase that is not homogeneous causes column calculation approach with assumption form of droplet haves the character of constant cannot be applied again. The goal of this research is to build droplet distribution model and mass transfer model at various heights of extraction column both in continuous phase and in dispersion phase. Droplet distribution model is more accurately applied to describe droplet breaks distribution for extraction in glass ball packed column with average of errors 4.53% compared to raschig ring packed column with average error of 11.52 %. At glass ball packing, the mass transfer modeling with total droplet has errors average to 57.67% while at raschig ring packing the model has errors average to 121.38%. Glass ball packing column model has smaller mean errors compared to raschig ring packing column because the glass ball packing form is more regular than the raschig ring packing. The amount of error between the mass transfer models and the experiment is caused by difference of the initial number of droplets that exit from the nozzle in the half circle column and in the full circle column. Keyword: extraction, packed column, droplet distribution model, mass transfer model AbstrakUkuran tetesan dari fasa dispersi yang tidak homogen menyebabkan pendekatan perhitungan kolom dengan asumsi bentuk tetesan bersifat konstan tidak dapat digunakan lagi. Tujuan dari penelitian ini adalah untuk membangun model distribusi tetesan dan model perpindahan massa pada berbagai ketinggian kolom ekstraksi baik di fasa kontinu maupun di fasa dispersi. Model distribusi tetesan lebih tepat digunakan untuk memodelkan fraksi tetesan pecah hasil penelitian pada ekstraksi kolom isian bola kaca dengan rata-rata error sebesar 4,53% dibandingkan dengan kolom isian raschig ring yang mempunyai error sebesar 11,52 Pada isian bola kaca pemodelan perpindahan massa dengan tetesan total mempunyai error rata-rata sebesar 57,67% sedangkan pada isian raschig ring mempunyai error rata-rata sebesar 121,38%. Model kolom isian bola kaca mempunyai error rata-rata yang lebih kecil dibandingkan dengan kolom kolom isian raschig ring, dikarenakan model isian bola kaca bentuknya lebih beraturan dibanding dengan kolom isian raschig ring yang bentuknya lebih tidak beraturan. Besarnya error perpindahan massa antara model dengan percobaan disebabkan oleh tidak samanya jumlah tetesan awal pada kolom setengah lingkaran dengan jumlah tetesan awal pada kolom lingkaran penuh.Kata kunci : ekstraksi,kolom isian, model distribusi tetesan, model perpindahan massa

A New Model for the Simulation of CO2 Absorption in an Industrial-Scale Packed Column

2012 ◽  
Vol 557-559 ◽  
pp. 2208-2216 ◽  
Author(s):  
Wen Bin Li ◽  
Guo Cong Yu ◽  
Bo Tan Liu ◽  
Xi Gang Yuan
Keyword(s):  
Mass Transfer ◽  
Packed Column ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Industrial Scale ◽  
Transfer Model ◽  
Turbulent Heat ◽  
Proposed Model ◽  
Heat Conservation ◽  
Phase Temperature

A new computational mass transfer model is proposed for simulating the chemical absorption process with heat effect by solving the average fluctuating mass flux in turbulent mass conservation equation and the average fluctuating heat flux in turbulent heat conservation equation, so that the concentration profile and the temperature profile of column can be obtained. The feather of the proposed model is to abandon the conventional way of introducing the unknown turbulent mass transfer diffusivity Dtand the turbulent thermal diffusivity αtin the mass and heat conservation equations. By using the proposed model, the simulated results of CO2absorption by aqueous monoethanolamine (MEA) solution in an industrial scale column is presented, including MEA concentration, CO2loading and liquid phase temperature. The simulations are in agreement with the published experiment data.

scholarly journals Dinamika tetes dalam kolom isian

2018 ◽  
Vol 7 (1) ◽  
pp. 710
Author(s):  
Danu Ariono ◽  
Dwiwahju Sasongko ◽  
Priyono Kusumo
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Size Distribution ◽  
Droplet Size ◽  
Droplet Diameter ◽  
Mass Transfer Rate ◽  
Packed Column ◽  
Droplet Size Distribution ◽  
Droplet Dynamics

To date, evaluation of the performance of liquid-liquid extraction in packed columns has not been able to produce satisfactory results, because the correlations used in this evaluation are empirical in nature, with a very limited range of validity. One of the causes of this limitation is the use of the assumption that the dynamics of liquid dispersed in droplets is constant (in terms of shape, dimensions, and numbers), so that the mass transfer interfacial area and mass transfer coefficient in the column are assumed to be constant. In reality, dynamics of droplets in a column is not constant, due to the imbalance between droplet coalescence and disintegration. For a given droplet diameter, there is an increase in numbers of droplets due to coalescence of smaller droplets, and a  decrease in numbers of droplets due to disintegration into smaller droplets. These coalescence and disintegration phenomena may be caused by various factors, including the existence of packings which impede the flow of droplets. These phenomena impact the mass transfer rate from continuous to dispersed phase, and vice versa, due to a variation in the interfacial contact area and mass transfer coefficient. The observation of droplet dynamics from droplet formation until its motion through void spaces between packings is a critical factor in developing a model that can describe the performance of the packed column. The dynamics of droplets is influenced by various operational and physical variables.  A droplet dynamics experiment has been undertaken, aimed at obtaining the droplet size distribution at specific heights along the column. This distribution is to be used to develop mass transfer coefficient correlations in the continuous and dispersed phases.Keywords: droplet size distribution, packed column Abstrak Evaluasi unjuk kerja ekstraksi cair-cair dalam kolom isian (packed column) hingga saat ini belum dapat memberikan hasil yang memuaskan karena korelasi-korelasi yang  digunakan  masih  bersifat  empiris serta daerah keberlakuannya sangat terbatas. Salah satu penyebab keterbatasan berlakunya korelasi tersebut ialah penggunaan anggapan bahwa dinamika cairan yang terdispersi dalam bentuk tetesan bersifat konstan (bentuk, ukuran serta jumlahnya), sehingga harga luas perpindahan massa dan harga koefisien perpindahan massa dalam kolom dianggap tetap. Kenyataannya dinamika tetesan dalam kolom tidak konstan akibat adanya tetesan yang bergabung dan pecah dalam jumlah yang  tidak sama. Pada suatu harga diameter tetesan tertentu, ada penambahan jumlah tetesan akibat penggabungan tetesan­ tetesan yang ukurannya lebih kecil serta adanya pengurangan jumlah tetesan akibat pecahnya tetesan menjadi tetesan-tetesan yang lebih kecil. Peristiwa penggabungan dan pemecahan tetesan dapat disebabkan berbagai faktor temasuk adanya isian yang menghalangi gerakan tetesan. Kejadian tersebut akan mempengaruhi laju proses perpindahan massa dari fasa kontinyu ke fasa  terdispersi  atau sebaliknya, karena adanya variasi luas permukaan kontak serta koefisien perpindahan massanya. Pengamatan dinamika tetesan mulai saat pembentukan tetes hingga pergerakannya saat melewati sela-sela isian merupakan faktor penting dalam  membangun model  yang  dapat menggambarkan unjuk kerja kolom isian. Dinamika tetesan tersebut dipengaruhi oleh berbagai variabel operasi dan variabel fisik. Eksperimen dinamika fetes yang dilakukan diarahkan untuk memperoleh distribusi ukuran tetes pada posisi ketinggian tertentu dan distribusi tersebut akan digunakan untuk pengembangan  korelasi koefisien perpindahan massa difasa  dispersi danfasa kontinyu.Kata kunci: distribusi ukuran tetes, kolom isian.

Hydrodynamics and mass transfer coefficients for a modified Raschig ring packed column

2014 ◽  
Vol 50 (10) ◽  
pp. 1385-1392 ◽  
Author(s):  
I. Mamaliga ◽  
D. Sidor ◽  
C. Condurat ◽  
E. T. Iacob Tudose
Keyword(s):  
Mass Transfer ◽  
Packed Column ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Raschig Ring

Henry's constants and mass transfer coefficients of halogenated organic pollutants in an air stripping packed column

1998 ◽  
Vol 38 (6) ◽  
pp. 287-294 ◽  
Author(s):  
Pen-C. Chiang ◽  
Chung-H. Hung ◽  
J. C. Mar ◽  
E. E. Chang
Keyword(s):  
Mass Transfer ◽  
Methylene Chloride ◽  
Packed Column ◽  
Transfer Coefficients ◽  
Chlorinated Organic Compounds ◽  
Air Stripping ◽  
Mass Transfer Coefficients ◽  
Equilibrium Partition ◽  
Henry's Constants ◽  
Chlorinated Organic

Both Henry's constants and volumetric mass transfer coefficients (KLa) of eight priority chlorinated organic compounds including 1,1-dichloroethene, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,4-dichlorobenzene in an air stripping packed column were investigated in this study. The liquid and gas phase EPICS (Equilibrium Partition in Closed System) and direct calculating methods were applied to determine the Henry's constants of VOCs. The interference of co-solute on Henry's constants was also investigated. Experimental results indicated that decrease in Henry's constants of VOCs was observed in the presence of humic acid but no apparent effect on Henry's constants was detected when there was NaCl and surfactant in solution. Four different configurations of packing media including Intalox Saddle, Super Intalox Saddle, Telleret, and Hedgehog made of polypropylene were respectively packed in the air stripping tower and investigated in the study. The dependence of hydraulic loading, air-water ratio, and configurations of packing media on mass transfer coefficients of VOCs was discussed.

A Method for Estimating Mass Transfer Coefficients in a Packed Column Using Reactive Absorption Data

2005 ◽  
Vol 70 (3) ◽  
pp. 383-402
Author(s):  
Valery A. Danilov ◽  
Il Moon
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Optimization Technique ◽  
Packed Column ◽  
Effective Area ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Model Calculations ◽  
Unit Model ◽  
Reactive Absorption

This paper is devoted to the development of a new method for estimating mass transfer coefficients and effective area in packed columns in the case of reactive absorption. The method is based on a plug-flow model of reactive absorption of carbon dioxide with sodium hydroxide solution. The parameter estimation problem is solved using an optimization technique. Some mass transfer parameters are found to be correlated. Global sensitivity analysis by Sobol's technique showed that the unit model with the defined objective function is sensitive to the estimated parameter. Case studies of reactive absorption with different packings illustrate application of the proposed method for estimating mass transfer coefficients and effective area from column operation data. The model calculations are compared with experimental data obtained by other authors. The concentration profiles calculated by the unit model with the estimated parameters are shown to match well with experimental profiles from literature. A good agreement between estimated values and experimental data from literature confirms the applicability of this method.

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