Column diameter extraction

Column diameter in. Amplitude, in. Plate spacing, in. Agitator speed, strokes/min Extractant Dispersed phase Minimum HETS Throughput, gal hr- ft-2 Volumetric efficiencies V/HETS,h" ... 

Extraction column packed column, diameter 0.5 m, height 4 m, packed height 3 m, packing 25 mm stainless steel pall rings, design pressure 2 bar, material carbon steel. 

No simple correlation is available to predict the flooding velocities in extraction columns, and hence the column diameter needed. The more specialised texts should be consulted to obtain guidance on the appropriate method to use for a particular problem see Treybal (1980), Perry et al. (1997) and Humphrey and Keller (1997). 

Leibson, I and BECKMANN, R. B. Chem. Eng. Prog. 49 (1953) 405. The effect of packing size and column diameter on mass transfer in liquid-liquid extraction. 

Logsdail, D. H. and Thornton, J. D. Trans. Inst. Chem. Eng. 35 (1957) 331. Liquid-liquid extraction. Part XIV. The effect of column diameter upon the performance and throughput of pulsed plate columns. 

In extractive distillation, the agent (sometimes termed solvent) is significantly less volatile than the regular feed components. The agent will be added near the top of the column. The agent behaves as a heavier-than heavy key component. It is also conveniently separated from the product streams. Because the agent usually must be added in fairly substantial amounts, this means that column diameters and heat loads are increased, while plate efficiencies arc lowered. 

Thus the extractor column raffinate outlet rate and the solvent inlet rate are approximately equal. This is indeed the minimum solvent rate allowed, since a lower rate will overload the solvent, referencing the plait point. This rate will also set the required minimum extractor column diameter. For some refinery-type extraction operations, such as lube oil extractors, where relatively much larger solvent-raffinate rates apply, this method for determining minimum solvent rate is very economical and desirable. 

Flooding in liquid-liquid extraction is similar to vapor-liquid flooding in that the controlling liquid-phase flow rate will cause blockage of the opposite liquid-phase flow if the diameter is too small. However, liquid-phase channeling can happen if the column diameter is too large. Keep-... 

Pulsed columns are generally not used for column diameters greater than 180 cm because of problems with mechanical support and pulse generation. The great amount of backmixing also causes uncertainties in column performance. Small pulsed columns have been successfully used for the extraction of metals from slurries (Warwick, 1973). 

Solid-phase microextraction (SPME) — is a procedure originally developed for sample preconcentration in gas chromatography (GC). In this procedure a small-diameter fused silica optical fiber, coated with a liquid polymer phase such as poly(dimethylsiloxane), is immersed in an aqueous sample solution. The -> analytes partition into the polymer phase and are then thermally desorbed in the GC injector on the column. The same polymer coating is used as a stationary phase of capillary GC columns. The extraction is a non-exhaustive liquid-liquid extraction with the convenience that the organic phase is attached to the fiber. This fiber is contained in a syringe, which protects it and simplifies introduction of the fiber into a GC injector. Both uncoated and coated fibers with films of different GC stationary phases can be used. SPME can be successfully applied to the analysis of volatile chlorinated organic compounds, such as chlorinated organic solvents and substituted benzenes as well as nonvolatile chlorinated biphenyls. 

The stripper required to process the aqueous phase for recovering n-pentane and ethanol requires a few more trays, but it has a column diameter less than half that of the solvent recovery column for the extractive distillation scheme. The heat loads are also much smaller. The top product, consisting of n-pentane, ethanol, and some water, is recycled to the reflux stream of the extractive distillation column. 

To operate SMB chromatography a lot of parameters (column diameter, column length, total column number and number of columns per section, eluent, feed, raffinate, extract and recycle fluid flow and switch time interval) have to be chosen correctly. Therefore, design and process optimization should be done by computer simulations. It is much more difficult to optimize SMB during nonlinear conditions as compared to linear conditions. In fact, empirical approaches for optimization during overloaded and non-linear conditions are in most cases even impossible [96, 97], Computer-assisted optimization is therefore especially important for chiral separations since these CSPs have in general lower saturation capacities compared to non-chiral columns (see paper III). 

The countercurrent contact zone height will depend primarily upon the number of stages required ( ) and the column characteristics. The effect of backmixing also increases the column diameter. A reasonable first approximation of extraction height (L) required for agitated columns is ... 

A total of 5g polyamide powder (trade quality) is added to the extract and thoroughly mixed, and the mixture is filled in a glass column (diameter, 1 cm length, 15 cm) and eluted in three steps ... 

Estimate the diameter and height of an RDC column to extract acetic acid from water using isopropyl ether for the conditions and data of Problem 7.21. For the desired degree of separation, 15 equilibrium stages are required. 

Optimal absorbent (stripping agent or extraction solvent) flow rate in an absorber (stripper or liquid-liquid extractor), for which the number of stages is balanced against the column diameter and absorbent (stripping agent or extraction solvent)... 

Figure 2 Flow diagram of pilot plant for larger diameter columns 1 - extraction column, 2 -distillation for solvent recovery, 3 to 6 - solvent storage,...

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