Rotating Disk Contactor RDC

Fig. 15. Mechanically agitated columns (a) Scheibel column (b) rotating-disk contactor (RDC) (c) asymmetric rotating-disk (ARD) contactor (d) Oldshue-Rushton multiple-mixer column (e) Kuhni column and (f) reciprocating-plate column.

The rotating-disk contactor (RDC), developed in the Netherlands (158) in 1951, uses the shearing action of a rapidly rotating disk to interdisperse the phases (Eig. 15b). These contactors have been used widely throughout the world, particularly in the petrochemical industry for furfural [98-01-1] and SO2 extraction, propane deasphalting, sulfolane [126-33-0] extraction for separation of aromatics, and caprolactam (qv) [105-60-2] purification. Columns up to 4.27 m in diameter are in service. An extensive study (159) has provided an excellent theoretical framework for scale-up. A design manual has also been compiled (160). Detailed descriptions and design criteria for the RDC may also be found (161). 

FIG. 23"37 Equipment for liquid/liquid reactions, a) Batch stirred sulfonator. (h) Raining bucket (RTL S A, London), (c) Spray tower with Loth phases dispersed. (d) Two-section packed tower with light phase dispersed, (e) Sieve tray tower with light phase dispersed, (f ) Rotating disk contactor (RDC) (Escher B V, Holland). (g) Oldshue-Rushton extractor (Mixing Equipment Co. ). 

Some examples of mechanically agitated contactors are the rotating-disk contactor (RDC), Karr, Oldshue-Rushton, Scheibel, and Kiihni columns shown in Figure 11. 

Rotating disk contactor, RDC, ARD contactor Mixco, Scheibel, Treybal, Oldshue-Rushton, Kuehni product of the density difference with the interfacial tension (Mg/m, mN/m) between 1 and 4 and number of theoretical stages needed >2. Low HETS can handle dirty liquids, large throughputs. Needs flow ratios 1 1. Difficulty handhng low interfacial tension systems that tend to emulsify. 

Rotating disk contactor, RDC, ARD contactor Mixco, Scheibel, Treybal, Oldshue-Rushton, Kuehni HETS is sensitive to rotor speed. HETS increases slightly with diameter. 0.5 m at 1 m diameter superficial velocity about 5.5 L/s m with Kuehni 9.7 L/s m. Mixco, Scheibel, Treybal, Oldshue-Rushton, diameter < 2.5 m RDC diameter < 9 m. More specific recommendations are Scheibel, HETS 0.1-0. 2 m with combined superficial velocity of 3-4 L/s m RDC HETS 0.3-0.4 m with combined superficial velocity of 4-8 L/s m Kuehni HETS 0.1-0. 2 m with combined superficial velocity of 2-3 L/s m. Total flow through a column = 10 L/s m with a density difference of 0.2 Mg/m. ... 

Liquid-Uquid Surface area 7-75 m /m. Rotating disk contactor, RDC, can handle dirty fluids and large throughputs. Need flow ratios 1 1 difficulty in handling... 

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