Bipolar Filter-Press Cells

An example of the horizontal cell is the Billiter cell, which employed a corrugated steel cathode covered with a mixture of long fiber asbestos and barium sulfate paste. These cells were used in Germany between the world wars and were completely replaced later by vertical diaphragm cells. 

There are two bipolar filter-press cell designs for manufacturing chlorine, the Dow cell and the Glanor cell. Both use finger-type electrodes, as opposed to flat plates. The Dow cells, developed over the past eighty years [76-79] are simple and rugged. They employ 

FIGURE 5.14. Dow Diaphragm-cell sectional view (a) Perforated steel back plate (b) Cathode pocket (c) Asbestos diaphragm (d) DSA anode (e) Copper back plate (f) Titanium back plate [85]. (Wth permission from John Wiley Sons, Inc.) 

The Dow electrolyzers have 50 or more cells in one unit and each electrical circuit may consist of only two of these units. The cells operate at about 80°C, allowing the use of vinyl ester resins and other plastics for cell construction. Because of the low operating current density, the cell voltage is only 300-400 mV above the thermodynamic 

There are two versions of the Glanor electrolyzer V-1144 containing 11 cells, each having an area of 35 m, and V-1161 containing 11 cells, having an area of 49 m per cell. The Glanor cells are currently used only by PPG Industries in the United States, Mexico, and Russia. 

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Figure 5.6 Comparison of I-V characteristics for a solid electrolyte and conventional bipolar filter press cell Temperature SO C,...

The electrode is set into a bipolar element, which consists of a channel frame surrounding the anodes, lined with titanium for protection against corrosion in the anolyte environment. The elements, with the anode side of one facing the cathode side of another, thereby forming a cell, are clamped together with tie-rods. The resulting assemblage has the appearance of a plate and frame filter-press—a commonly used piece of equipment for filtration operations. Hence, the term bipolar filter-press cell. ... 

The vertical electrode bipolar filter press cell developed by Dow Chemical... 

The advances made over the past several decades to improve the performance of electronic circuitry, e.g. rectifiers, have made electrolyzers increasingly commercially viable. Furthermore in advanced electrolyzers a series cell configuration is used (bipolar filter press, SPE, etc) and hence there is no need to work in low voltage high current mode with its inherent I R electrical losses. Consequently, the dormant magnetolysis field stands a good chance of remaining dormant. 

Bipolar electrodes are suspended or inserted into an oblong vessel of rectangular cross section or arranged to form the so called filter press cell. The first method is used mainly for the electrolytical refining of metals where the crude... 

Electrodialysis — In electrodialysis electrically charged - membranes and an electrical potential difference are used to separate ionic species from an aqueous solution and uncharged components. It refers to an industrial-scale process of electrolyte concentration/depletion due to separation on anion- and cation-exchange membranes under the influence of an electric field. The electrodialysis cell is constructed like a bipolar filter-press electrolyzer, with anion-exchange membranes sandwiched alternately with cation-exchange membranes, see following Figure. 

The first water electrolyzers used the tank design and an alkaline electrolyte.20 These electrolyzers can be configured as unipolar (tank) or bipolar (filter press) designs. In the unipolar design (see Figure 1), electrodes, anodes, and cathodes are alternatively suspended in a tank. In this design, each cell is connected in parallel and the entire system operated at 1.9-2.5 Vac. 

The old design of cell is based on a lead-lined tank filled with aqueous sulphuric acid, and the spent chromic acid solution in porous ceramic pots was placed in the tank. The anodes were lead rods dipped into the ceramic pots and the cathode was the lining to the tank. The plant was obviously operated totally as a batch process. More modern and economic cells are now available they are based on a bipolar filter press concept with lead alloy anodes, steel cathodes and a Nafion protonconducting membrane. The energy consumption and space time yields with such... 

BASF in Germany considered the use of the capillary gap cell (see Fig. 2.16 in Chapter 2) for this electrolysis. The cell consists of a stack of carbon discs closely spaced by 0.2 mm thick strips of an insulator. The electrolyte is pumped through the inter-electrode gaps and a voltage is applied to endplates so that a bipolar cell is formed. The cell design is compact, simple and cheap compared with a filter press cell and the tetraalkylammonium concentration could be reduced to below 0.5% without loss of yield and with an energy consumption below 3000 kWh ton . ... 

PPG and DeNora jointly developed a bipolar filter-press diaphragm cell called the Glanor electrolyzer [32]. The central design feature is the bipolar electrode where one side acts as an anode and the other as a cathode. The electrode consists of a steel plate to which anode fingers are connected on one side and cathode fingers on the other. 

The Dow Chemical Company is the largest chlor-alkali producer, accounting for one-third of the U.S. production and one-fifth of the world capacity. Because Dow s production capacity is laige and concentrated in a few sites, Dow s cell development followed a different path than other chlor-alkali technology developers. Dow uses its own cell design of the filter press bipolar type. Dow has operated filter press cells for... 

Water electrolyzer units typically consist of several cells or electrodes arranged in two basic configurations, tank type operated in unipolar configuration, or filter press type operated in bipolar configuration. Tbe most common configuration, see Fig. 2.1, is the unipolar tank type where each electrode has only one polarity and all the electrodes of the same polarity are connected in parallel. The anodes and cathodes are alternately connected, with the... 

The design of BP for PEMFCs is dependent on the cell architecture, on the fuel to be used, and on the method of stack cooling (e.g., water or air-cooling). To date, most of the fuel cells have employed traditional filter-press architecture, so that the cells are planar and reactant flow distribution to the cells is provided by the bipolar plate. The bipolar plate therefore incorporates reactant channels machined or etched into the surface. These supply the fuel and oxidant and also provide... 

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