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INDUSTRIAL QUALIFICATION OF GDE (GAS DIFFUSION ELECTRODES) TECHNOLOGY
All the above concepts have found an effective application in the UHDENORA bipolar electrolyser with a filter press configuration. Fig. 5 shows the structure of an elementary cell equipped with ODC. First of all we wish to remark that the cell structure is completely metallic and there is no part made of graphite. The anodic compartment is made of Ti Alloy and the anode mesh, made of DSA® coated Ti/Pd, is directly welded to the compartment structure. The cathodic compartment is made of Ti/Pd and does not support directly the cathode, but just a cathodic current distribution mesh. Between the two chambers a membrane is interposed. The membrane is pressed against the oxygen depolarised cathode by the differential pressure existing in the two compartments. The same differential pressure presses also the ODC against the cathodic current distribution mesh.
The combination of the above concepts, i.e ODC and Metal Electrolyser, constitutes the core of the new technology. Figure 6. is a picture of the demo electrolyser that was installed in the Bayer plant at Leverkusen.
A demonstration plant of 10000 tons per year Chlorine capacity, is installed in Leverkusen. The plant has been running since January 2000 (first start-up with 76 cells with first generation ODCs-Pt based catalyst). Second start-up was in May 2001 due to installation of 35 cells with hand-made second generation ODC (RhxSy based catalyst). Third start-up was in January 2003 for the installation of machine made second generation ODC (RhxSy) piloting production for the industrial reference plant which followed in Brunsbüttel. The first commercial plant is installed at Bayer Brunsbüttel serving an isocyanate plant. Plant capacity is 20000 ton per year of Chlorine (two electrolysers of 10000 ton each). First electrolyser was started-up in October 2003 and is in continuous operation (collecting lifetime). Second electrolyser was started up in May 2004. Operational experience of both demonstration and industrial plants has confirmed:
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