Rotating disk contactor

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). 

Shell process. Universal Oil Pro-ducts sulfolane sulfolane selectivity and capacity insensitive to water content caused by steam-stripping during solvent recov-ery heavy paraffinic countersolvent use 120 rotating-disk contactor, up to 4 m in diameter the high selectivity and capacity of sulfolane leads to low solvent-feed ratios, and thus smaller equip-ment... 

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. ). 

FIG. 23-38 Efficiency and capacity range of small-diameter extractors, 50 to 150 mm diameter. Acetone extracted from water with toluene as the disperse phase, V /V = 1.5. Code AC = agitated cell PPC = pulsed packed column PST = pulsed sieve tray RDC = rotating disk contactor PC = packed column MS = mixer-settler ST = sieve tray. (Stichlmair, Chem. Ing. Tech. 52(3), 253-255 [1980]). 

Rotating disk contactors or other rotary agitated towers reaiize NETS in the range 0.1-0.5 m. The especially efficient Kuhni with perforated disks of 40% free cross section has NETS 0.2 m and a capacity of 50 hr. 

Use of w/o-MEs for transport in liquid emulsion membrane separations Perforated rotating disk contactor Spray column Packed column... 

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

Brodkorb M, Slater MJ. Multicomponent and contamination effects on mass transfer in a liquid-liquid extraction rotating disk contactor. Trans IChemE 2001 79(part A) 335-346. 

Spray, packed, and sieve-plate columns give poor mass-transfer rates for consequently require greater height. The mass transfer in such columns can be significantly improved by providing mechanical agitation. Remen (1951) and Oldshue and Rushton (1952) introduced the rotating-disk contactor (see Fig. 26b) and the mixed column (see Fig. 26c). 

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