Simulation of fluid dynamics in a pulsed sieve plate column

Abstract

The present contribution reports on a new method for the simulation of the dispersed phase behaviour in liquid-liquid extraction columns. The fluid dynamic description is based on a mathematical model which explicitly takes into account drop transport, break-up and coalescence mechanisms, via a drop population balance along the column. Application of the model requires some simple measurements on single drops in order to determine transport and break-up laws, which are required by the model, and possibly also coalescence parameters. In this study the model is applied to pulsed sieve plate columns. The specific example considered here is based on systematic studies on the determination of break-up rates from the corresponding probabilities of break-up and the generated daughter drop size distributions by means of high-speed photography. The validity of the model was subsequently tested by comparison with some experimental results from studies on two different pulsed columns 80 and 225 mm in diameter for the watedtoluene system without mass transfer. The satisfactory agreement between the results justifies the use of such a method for the description of the behaviour of liquid-liquid extraction columns in a wide range of operating conditions. Furthermore, application of the model may help to dispense with long and expensive pilot tests.

Drop sizes and population balance model for a Karr column

“…Earlier studies of breakage probability in columns were conducted by Gourdon et al 17,19,36 Single drop experiments were performed in small lab‐scale breakage devices, where the internals remained the same as in real columns. They proposed a correlation for breakage probability with the critical Weber number (or critical drop diameter), which is the maximum Weber number (or drop diameter) that drops will not break up under certain operational conditions. Recently, based on the experimental and simulation study of the single drop breakage in a reciprocating plate column, 30 we proposed a correlation for the breakage probability as: where is the shear rate calculated by the simulation results.…”

“…Once solving it, the model will predict the drop size distribution along the column. The PBM has been applied in various types of columns in a stagewise or a differential form, for example, the rotating disc column, 15,16 pulsed sieve plate column, 17–20 Kühni column, 21,22 and some newly designed columns 23,24 . In these studies, terms of drop behaviors usually come from two ways: from the previous literature or from the single drop study 25 .…”

Distinct and Quantitative Validation Method for Predictive Process Modeling with Examples of Liquid-Liquid Extraction Processes of Complex Feed Mixtures

“…While some researchers found good agreement with axial dispersion model predictions and experimental data like Reissinger [38], the development of models that specifically account for coalescence and breakage of drops by population balance models (PBM) began. Jirnicy et al [39,40], Cassamata and Vogelpohl [41], Haverland et al [42], Al Khani et al [43] , Cruz-Pinto and Korchinsky [44], Coulaloglou and Tavlarides [45], Tavlaritis and Bapat [46] and Hamilton and Pratt [47] were the major contributors to develop and expand on this model type. The three major modeling approaches to LLE in extraction columns at this point in time and their respective system boundaries are shown in Figure 4.…”

Simulation of coalescence and breakage: an assessment of two stochastic methods suitable for simulating liquid–liquid extraction

“…An assumed distribution is sometimes used instead of a theoretical model, e.g. uniform (Narsimhan et al, 1979), Beta (Haverland et al, 1987) or normal (Coulaloglou and Tavlarides, 1977). The second way of looking at the breakage rate is to take the frequency of production of the daughter particles, so that the function f (x, y) is the rate at which a particle of size x and a particle of size y are formed from the breakage of a particle of size x + y.…”