Electrolyser filter-press

Each Nestpak module in the BiChlor electrolyser is sealed along its perimeter by a combination of a bolted flange and gaskets. This allows the sealing pressure to be controlled around all of the perimeter of each individual Nestpak. In a large-area bipolar filter-press electrolyser, sealing is only achieved with massive compression equipment and even then a variable sealing pressure is likely to exist around the module perimeter. 

The simplest kind of cell construction, shown in Figure 19.19(d), suffices for the production of hydrogen by electrolysis of water and for the recovery of chlorine from waste HC1. The term filter-press cell is applied to this kind of equipment because of the layered construction. These two electrolyses are economically feasible under some conditions. Some details are given by Hine (1985). 

Figure 1 Filter-press electrolyser configuration (O cathode, hydrogen...

The three-dimensional simulation domain is described Figure 1 for a two-compartment filter-press electrolyser. The cathode and anode compartments are separated by a rigid impermeable membrane, to prevent S02 crossover. The conductivity of a CMX Neocepta membrane is assumed for simulation. Both Pt electrodes are flat and parallel. Counter-current fluid flow is maintained under steady-state conditions in the plane-parallel compartments. The dimensions are those of the FM01-LC model, manufactured by ICI Chemical Polymer Company, and used in the Westinghouse pilot test facility implemented in the Marcoule Laboratory [9],... 

A parameter study of the two-phase filter-press electrolyser was carried out in the scope of optimizing the Westinghouse electrochemical step. The process sensitivity to biphasic phenomena was qualitatively assessed using a multiphysics model. 

Jomard J, Feraud J.P., Morandini J., Du Terrail Couvat Y. Caire J.P., Hydrogen filter press electrolyser modelled by coupling Fluent and Flux Expert codes. Jal of Applied Electrochemistry, 38, pp. 297-308, 2008. 

In the case of well-known electrochemical reactions, as well as for electrolyses where larger scales are involved, two-electrode cells (connected to a galvanostat) can be used with continuous feed of the reactant to the working electrode. This type of electrolysis is suitable for industrial purposes where specific devices and cells are utilized. Since electrodes of large areas are necessary, the distance between the anode and the cathode is small and determines the cell geometry (e.g. capillary-gap cell or filter-press cell). The use of cells equipped of porous electrodes (materials like graphite or carbon moss, platinum, nickel) have also been developed to perform electrocatalytic reactions at very large surfaces. Some typical cells used in the laboratory and in industry are presented at the end of this review. 

The year 1995 saw the debut in Germany of an advanced pressurized filter-press electrolyzer designed by the Gesellschaft fur Hochleistungs-elektrolyseure, a joint venture of Daimler-Benz Aerospace Airbus, Hamburgische Electricitatswerke, and Norsk Hydro Electrolysers. 

Three types of water electrolyser based on a tank cell, a filter press design and the use of elevated pressure are presently manufactured in various sizes to meet the various markets described above. In addition, a solid electrolyte cell is expected to become available by the mid-1980s. All these cells are described below. 

Figure 5.3 CJB bipolar filter press type water electrolyser.

Figure 5A A CJB B60 type filter press water electrolyses This unit has 60 cells and... 

On the other hand the De Nora electrolysis unit is well described in the literature (26. 27). The standard assembly was composed of 40 cells of the filter-press type (De Nora was already in the water electrolyser business). The diaphragm itself consisted of PVC cloth pressed between the ribs of graphite anodes and cathodes so as to separate the electrodes by a width of 2 mm. The life expectancy of such a diaphragm, under good operating conditions, was approximately three years. 

Brown, C.J., Hammond, J.K., Fletcher, D. et al. (1992) Mass Transport in Filter Press, Monopolar (FM-type) Electrolysers, Part II - Laboratory Studies in the FMOl-LC Reactor. Dechema Monograph, 123, 299-315. 

Brown, C.J., Walsh, F.C. and Fletcher, D. (1995) Mass transfer and pressuredropinalaboratory filter-press electrolyser. Transactions of the Institute of Chemical Engineers, 73A, 196-205. 

Vizquez, L., Alvarez-Gallegos, A., Sierra, RZ. et al. (2010) Prediction of mass transport profiles in a laboratory filter-press electrolyser by computational fluid dynamics modelling. Eiectrochimica Acta, 55, 3446-3453. 

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