Mixing columns

Without going into details of the chromatographic method, a SAR separation (asphaltenes having been eliminated) can be performed in a mixed column of silica followed by alumina. The saturated hydrocarbons are eluted by heptane, the aromatics by a 2 1 volume mixture of heptane and toluene, and the resins by a 1 1 1 mixture of dichloromethane, toluene and methanol. 

Inline motionless mixers derive the fluid motion or energy dissipation needed for mixing from the flowing fluid itself. These mixers iaclude orifice mixing columns, mixing valves, and static mixers. 

Orifice Mixing Column An orifice mixing column consists of a series of orifice plates contained in a pipe. The pipe normally is fabricated of two vertical legs connected by a return bend at the bottom with the orifice plates installed between flanges in the vertical legs. Typical use is for cocurrent contacting in caustic and water washing operations. 

Nonetheless, since the additives-mixing column will be used for absorption, the whole flowrate of S (0.08 kg mol/s) should be fed to the column. Hence, according to Eq. (3.11b), the outlet composition of Si is 0.0055. The same result can be obtained graphically as shown in Fig. 3.13. It is worth recalling that the target... 

Oriented polystyrene film, 23 408-409 Orifice mixing columns, 16 712 Orifice plates, 11 657-659 26 680 Orifice viscometers, 21 729-730 ORIGEN code, 19 673 Orimulsion, 3 769... 

Figure 10.15. Online sample conditioning using turbulent-flow mixing column (Hendricks, 2005).

Pertraction (PT) can be realized through a liquid membrane, but also through a nonporous polymeric membrane that was applied also industrially [10-12]. Apart from various types of SLM and BLM emulsion liquid membranes (ELM) were also widely studied just at the beginning of liquid membrane research. For example, an emulsion of stripping solution in organic phase, stabilized by surfactant, is dispersed in the aqueous feed. The continuous phase of emulsion forms ELM. Emulsion and feed are usually contacted in mixed column or mixer-settlers as in extraction. EML were applied industrially in zinc recovery from waste solution and in several pilot-plant trials [13,14], but the complexity of the process reduced interest in this system. More information on ELM and related processes can be found in refs. [8, 13-16]. 

The advantages and disadvantages of membrane based processes and pertraction through various types of liquid membranes are summarized in Table 23.5. HF contactors are supposed in these processes with the exception of pertraction into stable emulsions (ELM) where mixed column contactors or mixer-settlers are used. 

U. Lund and S. H. Hansen, Simultaneous determination of atropine and its acidic and basic degradation products by mixed-column HPLC, J. Chromatogr., 767 371 (1978). 

Time (sec.) Absorbance of sample after mixing Column 12 3 4 ... 

Column 1 Catal Column 2 Mixing Column 3 Yield... 

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). 

Schematic of a supercritical fluid extractor. 1 = COj 2 = modifier 3 = pump 4 = oven 5 = mixing column 6 = extraction cell 7 = pressure regulator 8 = collection of the extract.

Diagram of the SFE system and details of the PEEK restrictor. 1 = polar modifier 2 = syringe pumps 3 = oven 4 = mixing column 5 = switching valve 6 = extraction cell 7 = block heater 8 = PEEK restrictor 9 = collection vessel. (Data from Reference 16.)... 

A more complete resolution of the DDT-derived compounds in the soil extracts was achieved by electron capture gas chromatography. A mixed column of 5% QF-1 and 5% Dow 11 was used in a Wilkens gas chromatograph. This column satisfactorily separated the pesticides present except in a few cases when an unknown material appeared in the same regions as p,p-DDT. In these cases, a column composed of either SE 30 or 2% neopentyl glycol succinate on Chromasorb W resolved this mixture. The unknown amounted to about 3 p.p.m. calculated as p,p-DDT. 

Castello G, Gerbino TC, Kanitz S. 1982. Gas chromatographic analysis of halocarbons in drinking water by headspace extraction and mixed column separation. J Chromatogr 247 263-272. 

Fig. 7.16. (A) Schematic diagram of SFE-HPLC coupled systems. (Al) SFE system 1 CO, cylinder, 2 filter, 3 cooler, 4 SFE pump, 5 tee connector, 6 six-port valve, 7 modifier pump, 8 oven for extraction chamber, 9 mixing column, 10 six-port valve, 11 extraction cell. (A2) Interface 12 restrictor, 13 six-port valve, 14 oven for the six-port valve, 15 cell trap, 16 liquid trap. (A3) HPLC system 17 HPLC pump for H,0 or HCl/MeOH, 18 six-port valve, 19 anion-exchange column, 20 HPLC column, 21 diode array detector, 22 computer. (B) Exploded view of the valves. (Reproduced with permission of Pergamon Press.)...

Table VI. Total Petroleum Hydrocarbons, IP on Soil Taken from Column Tops at Various Stages of Leaching and Flooding and from Mixed Column Soil after Hooding...

Stirring in Pipes and Mixing Columns 325 Fig. 8.13 Transformation of a tubular reactor in a chamber reactor... 

Tab. 8.1 Liquid throughput number Qt as a function of the number of stages z in the mixing column with turbine stirrers (h/d = 0.33 D/d = 0.5) from 547] number of stages z 2 3 4 5...

Mobile phase MeOH 50 mM ammonium acetate 75 25 (Mix column effluent with 50 mM ammonium acetate pumped at 0.5 mL/min.)... 

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