Column-type equipment

Class 1 equipment are also called column-type equipment. Under this category, there are the various multiphase contactors. Gas-liquid contactors include bubble columns, packed bubble columns, internal-loop and external-loop air-lift reactors, sectionalized bubble columns, plate columns, and others. Solid-fluid (liquid or gas) contactors include static mixers, fixed beds, expanded beds, fluidized beds, transport reactors or contactors, and so forth. For instance, fixed-bed geometry is used in unit operations such as ion exchange, adsorptive and chromatographic separations, and drying and in catalytic reactors. Liquid-liquid contactors include spray columns, packed extraction... 

The contribution of the equipment between injection unit and detector cell should be negligable in relation to the column for a sufficient column characterization short connections with narrow capillaries and zero dead volume unions are the precondition for reliable plate numbers. Every end fitting of a column causes additional band broadening. In the past a column type was offered that could be directly combined without any capillary links unfortunately, it has disappeared from the market. 

An impurities analytical procedure should be described adequately so that any qualified analyst can readily reproduce the method. The description should include the scientific principle behind the procedure. A list of reagents and equipment, for example, instrument type, detector, column type, and dimensions, should be included. Equipment parameters, for example, flow rate, temperatures, run time, and wavelength settings, should be specified. How the analytical procedure is carried out, including the standard and sample preparations, the calculation formulae, and how to report results, should be described. A representative chromatogram with labeled peak(s) should be included in the procedure. 

Fig. 9.4 A stopped-flow optical absorption cell equipped with two column-type cells for rapid electrolysis [7].

Gas chromatography. Gas chromatography (GC) was performed using a Carlo Erba 5300 instrument, equipped with an on-column injector. Two column types were used a fused silica capillary column (25 m x 0.32... 

This is used for the preparative scale separation of mixtures of compounds. There are many variations in detail of equipment and technique such as column type, column packing, sample application and fraction collection, many of which are a matter of personal choice and apparatus available. Typical arrangements are shown in Fig. 32.15 and for a detailed description of all these variations you should consult the specialist texts such as Errington (1997, p. 163), Harwood et al. (2000, p. 175) and Furniss et al. (1989, p. 209). 

The Army conducted pilot-scale studies of continuous flow column GAC equipment at Badger AAP and Milan AAP. At both sites, GAC treatment was found to be effective for removing every type of explosive from the water and removing 2,4- and 2,6-DNT to below detection levels. 

The great improvement in performance of pulse columns over other column-type contactors, and the simple and reliable equipment involved, have led to the widespread use of pulse columns in many solvent extraction operations separating and purifying nuclear materials. In addition to their use in some fuel reprocessing operations, as mentioned above, pulse columns have been used in uranium purification plants at Femald, Ohio [Cl], and Gore, Oklahoma (cf. Chap. 5). 

It is important to properly design and operate the condensate pot. In one case history (351a), a column preheater equipped with a steam inlet control scheme and with a condensate pot (no pump) experienced condensate removal problems upon turndown. It was not stated whether the Fig. 17.1e or / arrangement was used. Arrangement 17.1c needs the pump for avoiding this type of problem. Arrangement 17.1/ needs a sufQdently tell condensate pot (Sec. 17.1.3) and adequate operation of the level controller at tumed-down rates in order to avoid this problem. The author suspects that in this case (351a), one of these needs was not fulfilled. 

Supercritical fluid grade carbon dioxide (Scott Specialty Gases, Plums teadvi lie, PA) was used as the carrier fluid. A Lee Scientific Model 501 supercritical fluid chromatograph equipped with a flame ionization detector (FID) and a nitrogen-phosphorus detector (NPD) was the instrument utilized for these studies. Fused silica capillary columns (50 pm i.d.) were employed for all the experiments. Three column types with stationary phases of three different polarities were used SB-Methyl-100, SB-Biphenyl-30 and Carbowax 20M (0.25 pm films). Frit restrictors were used to maintain pressure and proper flow rates in the column. The restrictor was connected to the end of the column via a zero dead-volume union. The end of the restrictor was positioned in the detector at 1 mm below the end of the flame jet. The detector was operated at 325-350 C with nitrogen make-up gas at 25 mL/min. Split injection was used in these experiments with 0.2 pL injection rotor and a split ratio of approximately 10 1. 

Generally, immobilized biocatalysts are packed in a column-type reactor this apparatus is called bioreactor , which is an effective item of production equipment apphed to a biocatalyst, such as an inunobilized enzyme. The column apparatus containing the immobilized biocatalyst is the core of the bioreactor. Some typical models are shown in Fig. 22.1. 

The flow of solvent through the column should not be too rapid or the solutes will not have time to equilibrate with the adsorbent as they pass down the column. If the rate of flow is too low or stopped for a period, diffusion can become a problem—the solute band will diffuse, or spread out, in all directions. In either of these cases, separation will be poor. As a general rule (and only an approximate one), most macroscale columns are run with flow rates ranging from 5 to 50 drops of effluent per minute a steady flow of solvent is usually avoided. Microscale columns made from Pasteur pipettes do not have a means of controlling the solvent flow rate, but commercial microscale columns are equipped with stopcocks. The solvent flow rate in this type of column can be adjusted in a marmer similar to that used with larger columns. To avoid diffusion of the bands, do not stop the column and do not set it aside overnight. 

Figure 2.14 A stopped-flow optical absorption cell equipped with two column-type cells for rapid electrolysis. R, solution reservoir DP, Nj gas bubbling EC, electrochemical cell for flow electrolysis M, mixer FC, flow-type optical absorption cell L, light beam D, photodetector, CV, control valve (23, 24).

Two types of columns were employed by Veening et al. One was a 6-ft (or 12-ft) length of borosilicate glass tubing, 2mm i.d., packed with 100-120 mesh Gas Chrom-Q coated with 3.6% SE-30 the second column consisted of a 100-ft x 0.5mm i.d. stainless steel, support coated open tubular (SCOT) column coated with m-bis(m-phen-oxyphenoxy) benzene and Apiezon L (Perkin-Elmer). The injection block for the SCOT column was equipped with a split ratio restrictor of 1 4. The hydrogen flow rate was 24ml/min while that of air was 300ml /min. 

FIGURE 5.11. Left Minilabotron 2000 equipped with a three-necked batch reactor. Middle Mini-labotroD 2000 equipped with a vertical column type flow reactor. Right Minilabotron 2000 equipped with a SPDl-type flow reactor. (Reproduced with kind permission from SAIREM Manufacturer (www.sairem.com)). 

The first set of experiments describes the application of gas chromatography. These experiments encompass a variety of different types of samples, columns, and detectors. Most experiments maybe easily modified to use available equipment and detectors. 

Another example is the purification of a P-lactam antibiotic, where process-scale reversed-phase separations began to be used around 1983 when suitable, high pressure process-scale equipment became available. A reversed-phase microparticulate (55—105 p.m particle size) C g siUca column, with a mobile phase of aqueous methanol having 0.1 Af ammonium phosphate at pH 5.3, was able to fractionate out impurities not readily removed by hquid—hquid extraction (37). Optimization of the separation resulted in recovery of product at 93% purity and 95% yield. This type of separation differs markedly from protein purification in feed concentration ( i 50 200 g/L for cefonicid vs 1 to 10 g/L for protein), molecular weight of impurities (<5000 compared to 10,000—100,000 for proteins), and throughputs ( i l-2 mg/(g stationary phasemin) compared to 0.01—0.1 mg/(gmin) for proteins). 

External and internal loop air-lifts and bubble column reactors containing a range of coalescing and non-Newtonian fluids, have been studied (52,53). It was shown that there are distinct differences in the characteristics of external and internal loop reactors (54). Overall, in this type of equipment... 

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