Design of contactor

Knowledge of the plug velocity is key parameter in the design of contactors, since it defines the residence time, i.e. the time that the droplet remains in the contactor, while it affects the intensity of the internal circulations within the plug and thus the... 

Structured packing and bubble cup trays are commonly used in the design of contactor. 

The design of countercurrent contactors is considerably simplified when the solvents A and B are not significantly miscible. The mass flows of A and B then remain constant from one stage to the next, and the material balance at any stage can be written... 

The main objective for calculating the number of theoretical stages (or mass-transfer units) in the design of a hquid-liquid extraction process is to evaluate the compromise between the size of the equipment, or number of contactors required, and the ratio of extraction solvent to feed flow rates required to achieve the desired transfer of mass from one phase to the other. In any mass-transfer process there can be an infinite number of combinations of flow rates, number of stages, and degrees of solute transfer. The optimum is governed by economic considerations. 

As stated above, the design of an RDC contactor usually involves the performance of pilot tests due to the large number of factors whicF can influence performance. These pilot plant data must then be scaled-up to Rill commercial size. The following procedure is recommended. 

A systematic, rational analysis of both isothermal and nonisothermal tubular systems in which two fluids are flowing must be carried out, if optimal design and economic operation of these pipeline devices is to be achieved. The design of all two-phase contactors must be based on a firm knowledge of two-phase hydrodynamics. In addition, a mathematical description is needed of the heat and mass transfer and of the chemical reaction occurring within a particular system. 

If the vapor-phase temperature is to be evaluated from the Clausius-Clapeyron equation, the pressure in the two-phase tubular contactor must be known at each axial position. This need once again illustrates the necessity of obtaining an understanding of the hydrodynamics of two-phase systems in order to carry out the design of heat-transfer contactors. 

The design of two-phase contactors with heat transfer requires a firm understanding of two-phase hydrodynamics in order to model effectively the heat- and mass-transfer processes. In this chapter we have pointed out areas where further theoretical and experimental research is critically needed. It is hoped that design engineers will be motivated to test the procedures presented, in combination with their use of the details from the original references, in the solution of pragmatic problems. 

Countercurrent contactors, design of, 10 757 Countercurrent continuous centrifugal extractor, 10 781... 

The types of equipment used, which range from stirred tanks and mixer-settlers to centrifugal contactors and various types of columns, affect both capital and operating costs [9]. In the decision to build a plant, the choice of the most suitable contactor for the specific situation is most important. In some systems, because of the chemistry and mass transfer rates involved, several alternative designs of contacting equipment are available. In the selection of a contactor, one must consider the capacity and stage requirements solvent type and residence time phase flow ratio physical properties direction of mass transfer phase dispersion and coalescence holdup kinetics equilibrium presence of solids overall performance and maintenance as a function of contactor complexity. This may appear very complicated, but with some experience, the choice is relatively simple. 

There followed a brief discussion of equipment for carrying out solvent extraction in industrial practice, both by stagewise and differential contact. Some of the first principles for the design of differential contactors were outlined and the part played by the efficiency of extraction in continuous equipment was discussed. Finally there was an outline of methods for the control of solvent loss which forms probably the most important environmental aspect of the application of solvent extraction. 

Performance and Design of a Turbulent Bed (Contactor (TBC)) Cooling Tower... 

In this chapter, Section 10.2 gives an overview of the operation of the Argonne centrifugal contactor. Section 10.3 focuses on the design principles for this contactor. Section 10.4 discusses the worldwide applications of this contactor to solvent-extraction processes of interest to the nuclear and other industries. Comparisons with other types of contactors are made throughout the text, and a separate section is devoted to them in Section 10.4. However, because of their widespread use and the author s particular experience with them, the ANL contactor and its variations remain the primary focus. 

This subsection describes the design of a contactor stage and how that design affects contactor operation. It will be shown when to add or avoid a particular feature. The discussion follows the flow of the two immiscible liquids through a contactor stage liquid entry, mixing, separation, and liquid exit. Finally, criteria for motor selection are reviewed. 

Figure 10.17 shows an eight-stage 4-cm contactor. The motors are also face mounted, as discussed by Leonard (1988). There is only one leg between the two four-stage banks of contactors. In later units, one leg has been put at each end of each bank of contactors. This design makes it easier to handle individual banks of four contactor stages. A four-stage 10-cm contactor is shown in Figure 10.18. In this photograph, an overhead crane is lifting one of the motor/rotor assemblies out of the contactor housing.

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