Industrial Scale Columns

Few investigators have used large industrial scale equipment to test multicomponent efficiency models an exception is the work reported by Ognisty and Sakata (1987). Tests with a mixture of propane, isobutane, and -butane, were carried out in a column of 2.4-m 

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Figure 12.7 Purification of factor VIII complex using immunoaffinity chromatography. The immobilized anti-factor VIII antibody is of mouse origin. Antibodies raised against specific epitopes on both the VIII C and vWF components have both been successfully used. Industrial-scale columns would often exhibit a bed volume of several litres. Note that the different elements in this diagram are not drawn to the correct scale relative to each other...

We will neglect any delay time (deadtime) in the vapor line from the top of the column to the reflux drum and in the reflux line back to the top tray (in industrial-scale columns this is usually a good assumption, but not in small-scale laboratory columns). Notice that y T is not equal, dynamically, to x. The two... 

Practically all sources explain the increase of HETP with column diameter in terms of enhanced maldistribution or issues with the scale-up procedure. Lab-scale and pilot columns seldom operate at column-to-packing diameter ratios (DT/Dp) larger than 20 under these conditions, lateral mixing effectively offsets loss of efficiency due to maldistribution pinch. In contrast, industrial-scale columns usually operate at Dt/Dp ratios of 30 to 100 under these conditions, lateral mixing is far less effective for offsetting maldistribution pinch. 

Simulations of an industrial scale column with structured packing have been reported by Taylor et al. (1992). They modeled a packed C4 splitter that had an internal diameter of about 2.5 m and five beds of structured packing with a total height of approximately 37 m as shown in Figure 14.33. The feed, which contains predominantly isobutane and n-butane... 

Wall-stabilized foaming (cellular foam) may occur in small and pilot-size columns (Fig. 14.10). This type of foaming differs from the foaming experienced in industrial-scale columns by being wall-stabilized. A comprehensive description of this foaming phenomenon is given elsewhere (159). 

The effect of increasing column diameter is to increase the tendency for circulation, and hence to increase the axial mixing (62,63). However, extremely few measurements of axial mixing at the industrial scale are available, so large-scale contactor design must still rely quite heavily on empirical experience with the particular type of equipment. 

There are not many data on the scale-up of spray columns from pilot to industrial scale, so these types of calculations must be used for... 

A third parameter to consider is the column construction. Thus the sample applicator should provide optimal sample application to give the most performance possible out of the packed bed. Constructions should also allow simple, fast, and reproducible packing of the column. Because costs for repacking of columns are a substantial operating cost item in industrial chromatography, the selection of column construction from this point of view is also important. Some novel column constructions allow very simple procedures both for laboratory and for industrial scale (e.g., INdEX columns, see Section V). 

Chlorine oxidation of sodium chlorite has also been used on both an industrial scale (by mixing concentrated aqueous solutions) or on a laboratory scale (by passing CVair through a column packed with the solid chlorite) ... 

All these gas-liquid-particle operations are of industrial interest. For example, desulfurization of liquid petroleum fractions by catalytic hydrogenation is carried out, on the industrial scale, in trickle-flow reactors, in bubble-column slurry reactors, and in gas-liquid fluidized reactors. 

Ross (R2) measured liquid-phase holdup and residence-time distribution by a tracer-pulse technique. Experiments were carried out for cocurrent flow in model columns of 2- and 4-in. diameter with air and water as fluid media, as well as in pilot-scale and industrial-scale reactors of 2-in. and 6.5-ft diameters used for the catalytic hydrogenation of petroleum fractions. The columns were packed with commercial cylindrical catalyst pellets of -in. diameter and length. The liquid holdup was from 40 to 50% of total bed volume for nominal liquid velocities from 8 to 200 ft/hr in the model reactors, from 26 to 32% of volume for nominal liquid velocities from 6 to 10.5 ft/hr in the pilot unit, and from 20 to 27 % for nominal liquid velocities from 27.9 to 68.6 ft/hr in the industrial unit. In that work, a few sets of results of residence-time distribution experiments are reported in graphical form, as tracer-response curves. 

This process is carried out on an industrial scale in bubble columns [57]. Acetic acid and acetic anhydride are fed together with a recycle solution composed of acetic acid, acetyl chloride, monochloroacetic acid, dichloroacetic acid and hydrogen chloride. Under these conditions, acetic anhydride and hydrogen chloride give acetyl chloride spontaneously. 

The most difficult problem to solve in the design of a Fischer-Tropsch reactor is its very high exothermicity combined with a high sensitivity of product selectivity to temperature. On an industrial scale, multitubular and bubble column reactors have been widely accepted for this highly exothermic reaction.6 In case of a fixed bed reactor, it is desirable that the catalyst particles are in the millimeter size range to avoid excessive pressure drops. During Fischer-Tropsch synthesis the catalyst pores are filled with liquid FT products (mainly waxes) that may result in a fundamental decrease of the reaction rate caused by pore diffusion processes. Post et al. showed that for catalyst particle diameters in excess of only about 1 mm, the catalyst activity is seriously limited by intraparticle diffusion in both iron and cobalt catalysts.1... 

Many small proteins, in particular those that function extracellularly (e.g. insulin, GH and various cytokines) are quite stable and may be fractionated on a variety of HPLC columns without significant denaturation or decrease in bioactivity. Preparative HPLC is used in industrial-scale purification of insulin and of IL2. In contrast, many larger proteins (e.g. blood factor VIII) are relatively labile, and loss of activity due to protein denaturation may be observed upon high-pressure fractionation. 

An advantage of this approach to model large-scale fluidized bed reactors is that the behavior of bubbles in fluidized beds can be readily incorporated in the force balance of the bubbles. In this respect, one can think of the rise velocity, and the tendency of rising bubbles to be drawn towards the center of the bed, from the mutual interaction of bubbles and from wall effects (Kobayashi et al., 2000). In Fig. 34, two preliminary calculations are shown for an industrial-scale gas-phase polymerization reactor, using the discrete bubble model. The geometry of the fluidized bed was 1.0 x 3.0 x 1.0 m (w x h x d). The emulsion phase has a density of 400kg/m3, and the apparent viscosity was set to 1.0 Pa s. The density of the bubble phase was 25 g/m3. The bubbles were injected via 49 nozzles positioned equally distributed in a square in the middle of the column. 

Fig. 8. Fast semi-industrial scale separation of a protein mixture using an 80 ml CIM DEAE Tubular Monolithic Column. Conditions Column 80 ml CIM DEAE Tubular Monolithic Column Mobile phase Buffer A 20 mM Tris-HCl buffer, pH 7.4 Buffer B 20 mM Tris-HCl buffer +1 M NaCl, pH 7.4 Gradient 0-100% Buffer B in 30 s Sample 2 mg/ml of myoglobin (peak 1), 6 mg/ml of conalbumin (peak 2) and 8 mg/ml of soybean trypsin inhibitor (peak 3) dissolved in buffer A Flow Rate 400 ml/min Injection volume 1 ml Detection UV at 280 nm...

In designing industrial scale packed columns a balance must be made between the capital cost of the column and ancillary equipment on the one side, and the running costs on the other. Generally, reducing the diameter of the column will reduce the capital cost though increase the cost of pumping the gas through the column due to the increased pressure drop. 

The previous sections have pointed out that mathematical models of the processes must be proved by experiments, or adapted to experimental results with the aid of pilot extractors. For economic reasons, pilot extractors are usually much smaller than large-scale industrial apparatus. Pulsed pilot columns, for example, have a diameter between 30 and 250 mm, whereas industrial-size columns are up to 2500 mm and more in size. Thus, the question arises of whether or not the calculations or pilot experiments may be used for the dimensions of large-scale apparatus. This is a general problem for engineers. 

According to Coimbra et solvents play a central role in the majority of chemical and pharmaceutical industrial processes. The most used method to obtain artemisinin (1) from A. annua is through the use of organic solvents such as toluene, hexane, cyclohexane, ethanol, chloroform and petroleum ether. Rodrigues et al described a low-cost and industrial scaled procedure that enables artemisinin (1) enhanced yields by using inexpensive and easy steps. Serial extraction techniques allowed a reduction of 65% in solvent consumption. Moreover, the use of ethanol for compound extraction is safer when compared to other solvents. Flash column pre-purification employing silicon dioxide (Zeosil ) as stationary phase provided an enriched artemisinin (1) fraction that precipitated in hexane/ethyl acetate (85/15, v/v) solution. These results indicate the feasibility of producing artemisinin (1) at final cost lowered by almost threefold when compared to classical procedures. 

The ion exchange method previously described with resin columns has been completely abandoned by Rhone-Poulenc for industrial scale production of the individual rare earth elements. We still use it however in our laboratories and for... 

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