Separation processes, schematic

Some of the economic hurdles and process cost centers of this conventional carbohydrate fermentation process, schematically shown in Eigure 1, are in the complex separation steps which are needed to recover and purify the product from the cmde fermentation broths. Eurthermore, approximately a ton of gypsum, CaSO, by-product is produced and needs to be disposed of for every ton of lactic acid produced by the conventional fermentation and recovery process (30). These factors have made large-scale production by this conventional route economically and ecologically unattractive. 

Fig. 2. Schematic of alcohol reduction ia beverages. Countercurrent dialysis is combiaed with distillation. The separation process is isothermal, and high boiling iagredients, present ia the dialysate, are preserved. In this fashion, alcohol removal is accompHshed with minimal perturbation ia flavor.

Fig. 5-13. Schematic representation of the Akzo Nobel enantiomer separation process. Two liquids containing the opposing enantiomers of the chiral selector (FI and K) are flowing countercurrently through the column (4) and are kept separated by the liquid membrane (3). The racemic mixture to be separated is added to the middle of the system (1), and the separated enantiomers are recovered from the outflows of the column (2a and 2b) [64],...

Fig. 16.4. Schematic diagram of the basic membrane gas separation process.

Eigure 22-2 illustrates this process schematically for fluorine 9p + 10iH F Because any stable nucleus is more stable than its separated nucleons, nuclear formation reactions of all stable nuclides are exothermic. 

Figure 224. Separation process for enhancement of energy media transformation, (a) Schematic of the process, (A) an original equilibrium, (B) separation of hydrogen, (C) secondary equilibrium, (b) Relationship between separation process and reaction equilibrium line...

A chemical plant makes three products and uses three raw materials in limited supply as shown in Figure P7.23. Each of the three products is produced in a separate process (1,2,3) according to the schematic shown in the figure. 

The most widely encountered biphasic method commences with two immiscible phases, one containing the catalyst, the other the substrate or substrates, and was first recognized by Manassen in 1973 [1], Liquid phases may be immiscible if their polarities are sufficiently different, as explained in Chapter 1. The two phases are vigorously mixed allowing reaction between the catalyst and substrates to take place. When the reaction is complete, the mixing is stopped and the two phases separate. A schematic representation of such a process is illustrated in Figure 2.1. In the ideal system, the catalyst is retained in one phase ready for reuse and the product is contained in the other phase and can be removed without being contaminated by the catalyst. In certain cases, neat substrates may be used as one phase, without additional solvents. 

It has been shown above that the knowledge of the thermodynamic origins of phase separation processes allows one to reconstruct schematic phase diagrams. 

One particularly interesting system is the epoxy 2,6-dimethyl-4-heptanone as up to 40 wt % of this solvent can be easily mixed together with the epoxy precursors to generate a phase separation process. This allows one to verify experimentally the possible morphologies which were predicted based on the schematic phase diagram at concentrations below the phase inversion (see Fig. 7). Shown... 

Once mass transfer is completed, the drop phase must be separated from the continuous liquid. The basic event of the separation process is the coalescence of droplets producing a homophase. This can take place in a part of a countercurrent column especially provided for this purpose (see Figs. 9.1 and 9.5) or in a special settler (Fig. 9.23). If we wish to predetermine the separation process, the physical course of the droplet coalescence must be known. Figure 9.24 schematically illustrates the coalescence of a single drop... 

Figure 15.3 illustrates schematically the different stages of a continuous separation process using the emulsion liquid membrane. There are four main stages in the flow sheet (1) emulsification of the stripping phase... 

Fig. 3. Schematic of electrodialysis slack used in desalination and other separation processes...

The process of granulation was carried out batch-wise in a drum of diameter 0.5 and 0.4 m long at a constant rotational speed n = 20 rpm and constant drum filling (cp = 10%), for a range of moisture contents w [kg of water/kg of dry material] selected for each raw material separately. A schematic diagram of the experimental set-up is shown in Fig. 2. 

Figure 2.2 Schematic representation of the nominal pore size and best theoretical model for the principal membrane separation processes...

The second whey separation process uses both ultrafiltration and reverse osmosis to obtain useful protein from the whey produced in the traditional cheese manufacturing process. A flow schematic of a combined ultrafiltration-reverse osmosis process is shown in Figure 6.23. The goal is to separate the whey into three streams, the most valuable of which is the concentrated protein fraction stripped of salts and lactose. Because raw whey has a high lactose concentration, before the whey protein can be used as a concentrate, the protein concentration must be increased to at least 60-70% on a dry basis and the lactose content... 

Schematic representation of the exergy flow in a separation process.

Figure 6.1 Schematic illustrating in vivo membrane separation processes. Left microdialysis sampling probe with curved lines indicating analyte tortuous diffusion through the tissue into and out of the probe. Right ultrafiltration representing interstitial fluid flow into the membrane device. Tissue is represented with cells and hlood vessels (dark circles in light circles).

Separations in two-phase systems with one immobilized interface(s) are much newer. The first paper on membrane-based solvent extraction (MBSE) published Kim [4] in 1984. However, the inventions of new methods of contacting two and three liquid phases and new types of liquid membranes have led to a significant progress in the last forty years. Separations in systems with immobilized interfaces have begun to be employed in industry. New separation processes in two- and three-phase systems with one or two immobilized L/L interfaces realized with the help of microporous hydrophobic wall(s) (support) are alternatives to classical L/L extraction and are schematically shown in Figure 23.1. Membrane-based solvent extraction (MBSE) in a two-phase system with one immobilized interface feed/solvent at the mouth of microspores of hydrophobic support is depicted in Figure 23.1a and will be discussed... 

FIGURE 8 Schematic diagram showing the two basic modes of operating an adsorption separation process (a) cyclic batch two-bed system (b) continuous countercurrent system with adsorbent recirculation. Concentration profiles through the adsorbent bed are indicated. Component A is more strongly adsorbed than B. (Reprinted with permission from Ruthven, D. M. (1984). Principles of Adsorption and Adsorption Processes, copyright John Wiley Sons, New York.)... 

FIGURE 13 Schematic diagram showing the sequence of column interchange in a periodic countercurrent separation process. 

Distillation is the dominant separation process in the petroleum and chemical industries. It is carried out continuously more often than batchwise, in large, vertical, hollow cylindrical columns (or towers). Figure 1 shows a large distillation column with its associated piping, heat exchangers, vessels, ladders, platforms, and support structures. Figure 2 shows a simple schematic representation. 

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