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Electrodialysis equipment

The value of /jim is determined by the discontinuity in the dependence of cell current on applied cell voltage which occurs when the interfacial concentration approaches zero. The polarisation parameter is convenient in the design and scale-up of electrodialysis equipment. It can be easily measured in small-scale stacks at a given value of bulk concentration and then used to predict limiting current densities in larger stacks at other concentrations. Most stacks use operating values of the polarisation parameter that are 50-70 per cent of the limiting values. [Pg.467]

Figure 15.21. Electrodialysis equipment and processes, (a) View of the components of an electrodialysis stack Lacey, 1978). (b) Flow pattern through an electrodialyzer for removal of NaCl from water Ionics Inc.), (c) Electroreduction with the use of an ion exchange diaphragm (d) Flowsketch of a three-stage electrodialysis for treatment of brackish water Rogers, in Belfort, 1984). Figure 15.21. Electrodialysis equipment and processes, (a) View of the components of an electrodialysis stack Lacey, 1978). (b) Flow pattern through an electrodialyzer for removal of NaCl from water Ionics Inc.), (c) Electroreduction with the use of an ion exchange diaphragm (d) Flowsketch of a three-stage electrodialysis for treatment of brackish water Rogers, in Belfort, 1984).
TABLE 15.6. Performance of Electrodialysis Equipment on Treatment of 3000 ppm Brackish Water... [Pg.515]

Only one basic design of electrodialysis equipment for demineralization appears to be in use. This is an assembly of alternate cation and anion ion exchange sheets separated by spacers in groups of several hundred clamped together between electrodes. The assembly physically resembles a plate-and-frame filter press. Figures 15.21(a) and (b) show such assemblies, and some dimensional data were stated in Section 15.5, Electrodialysis. [Pg.517]

Electrodialysis equipment and process design The performance of electrodialysis in practical applications is not only a function of membrane properties but is also determined by the equipment and overall process design. As far as the stack design is concerned there are two major concepts used on a large scale. One is the sheet-flow concept, which is illustrated in Figure 5.3 and the other is the so-called tortuous path concept, which is illustrated in Figure 5.5. [Pg.100]

Substantial quantities of sodium chloride have been produced in Japan from sea water concentrates using other types of electrodialysis equipment the total output of such electrodialytic salt plants has exceeded 260000 tons per yearS). An electrodialysis stack consists of multiple pairs of ion exchange membranes, one membrane being permeable to anions (A) the other to cations (C) (Fig. 1). [Pg.97]

Multi-compartment electrodialysis equipment using ion-selective membrane was introduced in 1940. Figure 17.2 illustrates the working principle of such a cell. In the cell anion-selective membranes (a) alternate with cation-selective membranes (c). Under an applied d-c potential, cations M+ tend to move towards the cathode. These cations are able to permeate the cation-selective membranes but not the anion-selective membranes. Similarly, anions X tend to move towards the... [Pg.384]

Hi) Salt from sea water Another principal application of electrodialysis is the production of common salt from sea water. In the manufacture of salt from this source, generally sea water is first filtered and then warmed with waste heat. Next, this water is slowly passed through the depletion compartments of the multicompartment electrodialysis equipment. Concentration of solids reaches about 20% by weight in the brine collecting in the enrichment compartments. Further processing of this concentrated brine by evaporation yields the salt in solid crystalline state. [Pg.386]

As stated previously, the operating current density i is usually 50-70% of the limiting value. Vendors of electrodialysis equipment will recommend the percentage to be used in their equipment. [Pg.976]

If the scale problem did not exist, more water could be recovered by distillation. A concentration factor of 4 to 1 and possibly higher has been postulated. The scale decreases the efficiency of the distillation equipment. If it did not form, the equipment could be operated at higher temperatures and could be smaller, with considerable savings on capital costs. If the scale problem did not exist, electrodialysis equipment could be operated more efficiently, because the scale (particularly the gypsum) tends to foul the membranes. [Pg.36]

The yeast cells and residual sunflower oil were separated from the culture solution by cross-flow microfiltration with 0.2 pm pore size. The transformation of the ICAJ CA sodium salts from the cell-free culture solution to their corresponding acids and sodium hydroxide was performed using laboratory electrodialysis equipment with bipolar membranes. Details are described in Sect. 19.5.3. [Pg.405]

A number of surface treating processes reqnire a rinsing fluid, which dissolves salts produced in the process. It is possible to recover more than 80% of the salts in a rinsing fluid using electrodialysis equipment. This electrochemical process is particularly suitable for recovering salts of silver, copper, nickel and zinc. The method involves a large number of electrolytic cells in series. Each cell comprises a cationic membrane and an anionic membrane, with a spacer between each pair of membranes. [Pg.269]


See other pages where Electrodialysis equipment is mentioned: [Pg.192]   
See also in sourсe #XX -- [ Pg.100 ]

See also in sourсe #XX -- [ Pg.544 , Pg.545 ]

See also in sourсe #XX -- [ Pg.513 , Pg.514 ]

See also in sourсe #XX -- [ Pg.513 , Pg.514 ]

See also in sourсe #XX -- [ Pg.513 , Pg.514 ]




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