Holdup and characteristic velocity in a Hanson mixer–settler extraction column

2010 ◽  
Vol 88 (5-6) ◽  
pp. 703-711 ◽  
Author(s):  
M. Napeida ◽  
A. Haghighi Asl ◽  
J. Safdari ◽  
M. Torab-Mostaedi
2012 ◽  
Vol 18 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Mehdi Asadollahzadeh ◽  
Jaber Safdari ◽  
Ali Haghighi-Asl ◽  
Meisam Torab-Mostaedi

Dispersed phase hold-up has been measured in a 76.2 mm diameter pulsed packed column for four different liquid-liquid systems. The effects of pulsation intensity, phase ratio, and packing characteristic on the hold-up have been investigated under a variety of operating conditions. The dispersed phase axial hold-up shows a strong non-uniformity, depending on the operating conditions. The results indicated that the characteristic velocity approach is applicable to this type of extraction column for analysis of hold-up. An empirical correlation is derived for prediction of the hold-up in terms of operating variables, physical properties of the systems, and packing geometry. Good agreement between prediction and experiments was observed for all investigated operating conditions.


2020 ◽  
Vol 9 (8) ◽  
pp. e674982543
Author(s):  
Jarlon Conceição da Costa ◽  
Luiz Mário Nelson de Góis ◽  
Silvana Mattedi e Silva

The present work aims to evaluate the hydrodynamics of a pulsed packed extractor, with an internal diameter of 0.026m and a length of 1.0m, using the liquid butanol-water system. Thus, the basic parameters obtained for the hydrodynamic study of the extraction column in question as dispersed phase, slip velocity, characteristic velocity and flooding point. The methodology used in the work consisted of determining the holdup fraction of the dispersed phase, obtained through tests of simultaneous interruptions in the column feedings. The effects of frequency pulsation, dispersed phase flow rate and continuous phase flow rate investigated in the analysis of these parameters. New empirical correlations derived from the predictions of the parameters studied obtained in terms of operating variables and physical properties of the liquid system involved. The average absolute value of the relative error (AARE) was always below 5.6%. Good agreement between calculated and experimental results observed for all investigated operating conditions.


2016 ◽  
Vol 55 (3) ◽  
pp. 714-721 ◽  
Author(s):  
Yong Wang ◽  
Kathryn A. Mumford ◽  
Kathryn H. Smith ◽  
Zheng Li ◽  
Geoffrey W. Stevens

Author(s):  
Aleksandr F. BRAGAZIN ◽  
Alexey V. USKOV

Consideration has been given to orbit transfers involving spacecraft rendezvous which belong to a class of coplanar non-intersecting near-circular orbits of a spacecraft and a space station. The duration of the transfer is assumed to be limited by one orbit. The feasibility of a rendezvous using an optimal two-burn orbit-to-orbit transfer is studied. To determine a single free parameter of the transfer, i.e. the time of its start, ensuring a rendezvous at a given time or at a given velocity at the end of transfer, appropriate equations have been obtained To implement in the guidance algorithms optimal three-burn correction programs are proposed to achieve a rendezvous at a given time with a specified relative velocity at the moment of spacecraft contact. A range of phase differences at the start of maneuvering is determined, within which the characteristic velocity of the rendezvous is equal to the minimum characteristic velocity of the orbit-to-orbit transfer. The paper presents simulation results for “quick" rendezvous profiles that use the proposed programs. Key words: spacecraft, orbital station, “quick” rendezvous, orbit transfer, rendezvous program.


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