Analysis of observability of model parameters for physical absorption of poorly soluble gases in packed beds

1982 ◽  
Vol 47 (10) ◽  
pp. 2639-2653 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk
Keyword(s):  
Transfer Functions ◽  
Plug Flow ◽  
Packed Bed ◽  
Model Parameters ◽  
Packed Bed Column ◽  
Interfacial Transport ◽  
Complex Arithmetic ◽  
Physical Absorption ◽  
Poorly Soluble ◽  
Phase Lags

Expressions have been derived for four possible transfer functions of a model of physical absorption of a poorly soluble gas in a packed bed column. The model has been based on axially dispersed flow of gas, plug flow of liquid through stagnant and dynamic regions and interfacial transport of the absorbed component. The obtained transfer functions have been transformed into the frequency domain and their amplitude ratios and phase lags have been evaluated using the complex arithmetic feature of the EC-1033 computer. Two of the derived transfer functions have been found directly applicable for processing of experimental data. Of the remaining two one is useable with the limitations to absorption on a shallow layer of packing, the other is entirely worthless for the case of poorly soluble gases.

Theoretical analysis of counter-current absorption of a poorly soluble gas based on the PDE-AD model

1986 ◽  
Vol 51 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Gas Phase ◽  
Transfer Functions ◽  
Packed Bed ◽  
Packed Bed Column ◽  
Interfacial Transport ◽  
Gaseous Component ◽  
Poorly Soluble ◽  
Counter Current

Expression have been derived in the paper for all four possible transfer functions between the inlet and the outlet gas and liquid steams under the counter-current absorption of a poorly soluble gas in a packed bed column. The transfer functions have been derived for the axially dispersed model with stagnant zone in the liquid phase and the axially dispersed model for the gas phase with interfacial transport of a gaseous component (PDE - AD). calculations with practical values of parameters suggest that only two of these transfer functions are applicable for experimental data evaluation.

An experimental dynamic method of investigation of counter-current absorption of oxygen in water in a packed bed column

1987 ◽  
Vol 52 (7) ◽  
pp. 1715-1729 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk
Keyword(s):  
Transfer Functions ◽  
Simultaneous Detection ◽  
Harmonic Component ◽  
Packed Bed ◽  
Packed Bed Column ◽  
Oxygen Electrodes ◽  
Simultaneous Evaluation ◽  
Physical Absorption ◽  
On Line ◽  
Counter Current

An experimental method and technique are described in the paper of simultaneous detection of the transfer functions outlet-gas-stream-to-inlet-gas-stream and outlet-liquid-stream-to-inlet-gas-stream for the absorption of oxygen into water in a counter-current packed bed column. Both transfer functions were simultaneously monitored by means of three oxygen electrodes operating on the polarographic principle. The signals of these electrodes were processed in three steps to yield parameters of the model of physical absorption of gas. The first step was on-line evaluation of the Fourier coefficients of the principal harmonic component in all three monitored streams. The second step was the calculation of the frequency characteristics of both transfer functions while the third step yielded parameters of the model by optimization in the frequency domain. The method permits simultaneous evaluation of the parameters of the flow of both phases in the column and the interfacial transfer of oxygen.

Macroscopic fluid flow conditions in spiral wound membrane elements: packed bed approach

2000 ◽  
Vol 41 (10-11) ◽  
pp. 85-91 ◽  
Author(s):  
D. Van Gauwbergen ◽  
J. Baeyens
Keyword(s):  
Fluid Flow ◽  
Time Delay ◽  
Scale Up ◽  
Plug Flow ◽  
Packed Bed ◽  
Experimental Investigations ◽  
Model Parameters ◽  
Flow Conditions ◽  
Response Curves ◽  
Definition Of

The modelling of the reverse osmosis process is needed to fully evaluate its potential and facilitate scale up. The definition of the flow regime in the concentrate channel is of paramount importance. The present paper describes our experimental investigations on RTD and relates the RTD response curves to the regime of flow in the concentrate channel. Results demonstrate (i) that dead zones are present; (ii) that both a Plug Flow with Dispersion (PFD) and Probabilistic Time Delay (PTD) model can be used to characterise the flow; and (iii) that PFD- and PTD-model parameters assume nearly constant values for a given geometry which simplifies the prediction of the RTD for any desired flow rate.

Analysis of frequency responses of model flows of liquid in trickle beds

1982 ◽  
Vol 47 (11) ◽  
pp. 3032-3043 ◽  
Author(s):  
Vladimír Staněk ◽  
Milan Čársky
Keyword(s):  
Experimental Data ◽  
Mathematical Models ◽  
Imaginary Part ◽  
Packed Bed ◽  
Response Analysis ◽  
Packed Bed Column ◽  
Complex Arithmetic ◽  
Frequency Responses ◽  
Asymptotic Expressions ◽  
Real Experimental Data

Frequency responses have been derived for four mathematical models of the trickle flow in a packed bed column. The models contain gradually one to four parameters. Asymptotic expressions have been also obtained for the frequency responses under large values of the Peclet number. A possibility has been tested of using the complex arithmetic feature of a computer to evaluate numerically the model responses and to separate the real and the imaginary part of the response. Analysis has shown that all four models can be discriminated and their parameters are observable in the complex plane. This approach thus appears plausible for processing real experimental data as well as for the discrimination between various models.

An experimental study of gas phase back mixing under the counter-current gas-liquid flow on a vertical expanded metal sheet packing by static tracer technique

1980 ◽  
Vol 45 (1) ◽  
pp. 214-221
Author(s):  
Jan Červenka ◽  
Mirko Endršt ◽  
Václav Kolář
Keyword(s):  
Gas Phase ◽  
Flow Model ◽  
Plug Flow ◽  
Packed Bed ◽  
Metal Sheet ◽  
Concentration Profiles ◽  
Expanded Metal ◽  
Gas Liquid Flow ◽  
Counter Current ◽  
Back Mixing

Gas phase back mixing has been measured in a column packed with vertical expanded metal sheet under the counter-current flow of gas and liquid by the static method using a tracer. The observed experimental concentration profiles has not confirmed our earlier proposed model of back mixing, based on the concentration profiles in absorption runs. These profiles do not even conform with the axially dispersed plug flow model currently used to describe axial mixing in packed bed columns. The concentration profiles may be described by a combination of the axially dispersed plug flow model with back flow.

Column Study for Adsorption of Methylene Blue Dye using Azadirachta indica Adsorbent

2020 ◽  
Vol 17 (4) ◽  
pp. 47-52
Author(s):  
Vibha Goswami ◽  
Renu Upadhyaya ◽  
Sumanta Kumar Meher
Keyword(s):  
Methylene Blue ◽  
Flow Rate ◽  
Azadirachta Indica ◽  
Packed Bed ◽  
Blue Dye ◽  
Feed Flow Rate ◽  
Methylene Blue Dye ◽  
Packed Bed Column ◽  
Bed Height ◽  
Percentage Removal

In this study, synthesised Azadirachta indica adsorbent was used for the removal of methylene blue dye using a packed bed column. The effect of feed flow rate, feed methylene blue dye concentration, and bed height of column on percentage removal of dye was studied. It was observed that the column bed exhausted rapidly at a higher flow rate and therefore, a breakthrough occurred faster. However, it was observed that bed exhaustion time increases on increasing the bed height from 2 to 10 inch at 10 mg/L feed dye concentration and feed flow rate of 40 ml/min. It was also found that the breakthrough curve is more dispersed and the percentage removal of dye increases on decreasing the feed methylene dye concentration from 150 to 10 mg/L. The percentage removal was found to be 96.89% at 20 ml/min of feed flow rate under 10 inch of bed height and 10 mg/L of feed dye concentration. The atomic absorption spectrophotometer and scanning electron microscope were used for estimating the effluent dye concentration from the column and morphological study, respectively.

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