Перегляд за Автор "Maleta, Vladimir"

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Energy-saving technology of mass transfer in tray columns with separate phase movement
(2010) Maleta, Vladimir; Taran, Vitaly; Maleta, Bogdan
The comparison of formalized models, describing the operation of mass transfer column devices allows determining the type of equipment with the lowest power consumption in processes. For tray columns, the most widespread model is the model of theoretical contact phase, offered by McCabe-Thiele [1]. This model is based on the column material balance by distributed component and can be summarized in two postulates. 1. The concentration of volatile component in the contact phase is constant. 2. Vapor removing from the phase is in balance with liquid leaving the phase. In this case, the hydrodynamic indices of liquid and vapor flows are reduced to the perfect mixing models. The use of combinations of the other hydrodynamic models for liquid and vapor phases allowed Lewis to draw conclusions on significant enhancement of component separation. The greatest effect is achieved upon perfect displacement by vapor and liquid and single-direction movement of liquid in adjacent contact phases. All subsequent studies in this segment were aimed at industrial implementation of W.K. Lewis[2] conclusions. In particular, M.R. Cannon [3] suggested the following phase interaction mode. While the vapor passes through the column, the liquid doesn’t flow from tray to tray, and if the liquid overflows, it is not mixed on adjacent trays. The aim of the present paper is to determine the correlation between all offered models from the prospective of energy consumption during the separation process.
Hydrodynamics of liquid flow in the model of theoretical stage with perfect displacement
(2011) Maleta, Vladimir; Taran, Vitaly; Maleta, Bogdan
Pursuant to Lewis' work [1], the use of combinations of various hydrodynamic models of liquid and vapor phases enhances the efficiency of component separation on the tray. The greatest effect is achieved upon perfect displacement by liquid and vapor and sing-direction movement of liquid on adjacent contact degrees. In such conditions the efficiency of Murphy's tray may significantly exceed the local efficiency and reach 200-300% Cannon [2] suggested the way of phase interaction, for which during the passage of vapor through the column the liquid doesn’t overflow from tray to tray and upon liquid overflow it doesn't mix on adjacent trays (cyclic process). In a series of works [3, 4] it was shown that upon comparison of stationary and cyclic process both by the time of mass transfer on the tray and by the phase interaction nature the cyclic process is similar to the stationary process upon sing-direction movement of liquid on adjacent contact levels and perfect displacement by liquid and vapor. A mathematical model of the hydrodynamic processes occurring in a periodic cycled plate column is developed and experimentally confirmed.
Understanding process intensification in cyclic distillation systems
(2011) Maleta, Vladimir; Kiss, Anton; Taran, Vitaly; Maleta, Bogdan
The most effective separation possible in distillation columns takes place in the hydrodynamic regime where there is perfect displacement of the liquid and vapor streams. This can be achieved in distillation equipment with separate phase movement (SPM). Such an innovative route for process intensification in distillation is called cyclic distillation. The required process conditions are the lack of liquid outflow from the tray during vapor admission and the lack of liquid mixing in adjacent trays upon outflow of liquid. Remarkably, the throughput of such a column that operates in a controlled cycle mode is two or more times higher than the throughput reachable with conventional operation, at equivalent separation performance. In this study, a theoretical stage model with perfect displacement is proposed and the theory of the process working lines is developed. An adequate mass transfer model is also described along with the mode of calculation of tray columns operating in the cyclic operation mode. Sensitivity analysis was used to determine the effect of the key model parameters. The theoretical developments were implemented at industrial scale and subsequent testing showed an increase in the separation efficiency of 2-3 times as compared to the standard process.