Electrolyzers, membrane

Sro95Ybo. 05CeO3 x has been selected as the first protonic conductor to be evaluated as an electrolyzer membrane. 

Each plant needs an analytical schedule that is followed faithfully. Each relevant analysis must be performed at a specified fiequency. Since most chlor-alkali plants are built under some form of electrolyzer licensing arrangement, much of the analytical schedule is fixed by contract. In any event, the advice of suppliers of electrolyzers, membranes, and electrodes and their coatings is very important. Table 7.21 shows the recommended analyses and their frequencies for cells equipped with Nafion membranes [134]. 

Eig. 19. CME monopolar electrolyzer a, membrane b, cathode element c, half-cathode element d, current distributor e. Teflon tube f, CI2 + depleted brine manifold g, conductor rod h, CI2 + depleted brine outlet nozzle i, base frame j, recycled NaOH manifold k, recycled NaOH inlet nozzle 1, gasket (the gasket-to-element ratio is quite small) m, tie rod n, anode element o, H2 + NaOH manifold p, end plate, q, under cell bus bar (simplifies piping... 

In another development (32), the sodium sulfate solution produced during the desulfurization of paste with caustic soda is electrolyzed in a membrane ceU to produce caustic soda and high purity sulfuric acid. The caustic soda is recycled to the desulfurization stage the sulfuric acid, after concentration, can be reused in battery production. 

Highly pure perchloric acid can also be produced by a patented electrochemical process ia which 22% by weight hypochlorous acid is oxidized to chloric acid ia a membrane-separated electrolyzer, and then additionally oxidized to perchloric acid (8,84). The desired electrochemical oxidation takes place ia two stages ... 

Chlorine Engineers Membrane Electrolyzer, brochure no. EC-T002-3, Chlorine Engineers Corp., Ltd., Tokyo, 1991. 

D. Bergner, Membrane Electrolyzers for the Chlor-Mlkali Industy, Dechema-Monographs, Vol. 123, VCH VedagsgeseUschaft, New York, 1991, pp. 113-131. 

In the membrane-cell process, highly selective ion-exchange membranes of Du Font s Nation type are used which allow only the sodium ions to pass. Thus, in the anode compartment an alkali solution of high purity is produced. The introduction of Nafion-type membranes in chlor-alkali electrolyzers led to a significant improvement in their efficiency. Today, most new chlor-alkafi installations use the membrane technology. Unfortunately, the cost of Nafion-type membranes is still very high. 

Membranes in chlor-alkali electrolysis require highly pure brine feed the water used in membrane water electrolyzers must also be rather pure. 

Proton decay, delayed, 27 303-304 Proton-exchange membranes, 23 720 electrolyzer, 73 843 Proton exchange membrane process, 73 783... 

Membrane water electrolyzers, platinum and platinum metal cathodes, 40 122 p-Menthane, 20 281... 

Also, discussions of a number of applications of Nafion are not included in this document and are, at most, mentioned within the context of a particular study of fundamental properties. A number of these systems are simply proposed rather than in actual commercial applications. Membranes in fuel cells, electrochemical energy storage systems, chlor-alkali cells, water electrolyzers, Donnan dialysis cells, elec-trochromic devices, and sensors, including ion selective electrodes, and the use of these membranes as a strong acid catalyst can be found in the above-mentioned reviews. 

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