Current distributor

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... 

Fig. 25. OxyTech MGC electroly2er a, membrane b, anode assembly c, manifold spacer d, anolyte outlet e, catholyte outlet f, bulkhead g, brine inlet h, NaOH inlet i, insulating channel j, bulkhead insulator k, interface material 1, cathode assembly m, interceU bus n, tie rod o, current distributor p,...

Fig. 18.5 Specialised BiChlor mesh electrode design incorporating spider current distributors.

R. Meyer, in Explosives , Verlag Chemie, NY (1977), p 257, gives the current distributor in Switzerland as Vereinigung Schweizerischer Sprengstoff-Fabriken... 

Zadra cell — Electrolytic cell employed in -> electrowinning of gold. The design is based on placing into a perforated cylindrical polymer container steel wool as - cathode, a feeder tube, and a -> current distributor. The anode is a stainless steel mesh outside the container. Gold-rich solution is fed at low feed rate through the feeder at the bottom of the steel wool-filled compartment, gold is reductively extracted, and the extracted solution passes the polymer container. 

The ODC in this case may form together with the membrane an unit, that is, the porous electrode is (including the current distributor) directly attached to the membrane surface. The electrocatalyst needed for oxygen reduction in this case is located at the mem-brane/electrode boundary. Concerning the anode, the finite gap principle may be used. Figure 17 gives a scheme of the principle. 

FIGURE 5.19. MDC-55 cathode assembly showing current distributor blocks. (With permission from ELTECH Systems Corporation.)... 

S.5.3.2. Chlorine Engineers Electrolyzers. Chlorine Engineers Corporation (CEC), a subsidiary of Mitsui and Company, produces the filter-press type, monopolar membrane electrolyzer shown in Fig. 5.26 [94]. Uniform electrical current travels into each anode element through titanium-clad, copper-cored conductor rods and current distributors. The current distributor also serves as a downcomer, which promotes circulation... 

Chlorine and Caustic Technoiogy, Using Oxygen Depolarized Cathode, Fig. 5 Scheme of the ODC percolator cell, a Anode (titanium DSA), b cation-exchange membrane, c percolator, d oxygen-depolarized cathode (ODC, silver-PTFE gas diffusion electrode), e elastic element (fine. Interwoven nickel wire), / cathodic current distributor... 

ODC d, made of silver and PTFE (Bayer Material Science AG, BMS), within the so-called percolator c, a woven fabric which adjusts the flow rate of caustic soda solution. The ODC d and the cathodic current distributor f are electrically connected on their entire area by the elastic element e, made of fine, interwoven nickel wire. This elastic element e presses the ODC d, the percolator c, and the membrane b with optimized pressure onto the anode a. Therefore, the usual anode half shell of the conventional membrane process, completely filled with anolyte, can be apphed, and no falling film construction is necessary on the anode side as it is used in [10]. The percolator c withstands the pressure of the elastic element e and remains sufficiently permeable for the catholyte flow. Free oxygen gas transport into the ODC d is possible through the elastic element e. 

Oxygen gas conversion in an ODC requires an electrode design as gas diffusion electrode (GDE). The reaction is possible only in three-phase boundaries where the gas oxygen, the liquid electrolyte hydrochloric acid, and the solid electro-catalyst - electrically connected with the current distributor - are in optimal contact and any transport hindrance is minimized. 

The design of a PEM-type electrolyzer is relatively simple. As Figure 2.10 illustrates, it comprises a stack of elementary cells connected in a series by bipolar plates. Each cell comprises two electrodes separated by a Proton Exchange Membrane (PEM). Each electrode is made up of a thin catalytic layer which is the site of the oxidation (anode) or reduction reaction (cathode), and layers of porous materials which act as current distributors/receivers depending on the electrode in question. In general, this porous material will be incompressible (titanium) at the anode and compressible (carbon) at the cathode in order to add mechanical flexibility when the whole ensemble is compressed. 

Current receiver / Polymer Current distributor Channels... 

Figure 68. Four-stem anode for amalgam cells a) Active surface b) Current distributor c) Riser tube to protect the copper bar inside... 

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