Galvanostatic current interruption measurements for characterization of gas diffusion electrodes in chlor-alkali electrolysis

SummaryThe chlor-alkali electrolysis is one of the most significant processes in the chemical industry. In comparison to other inorganic-chemical processes it possesses one of the highest production applications. The electrochemical process for production of chlorine and caustic soda has been known since the end of the 19th century. On the grounds of new developments and improvements in the process, it was possible to reduce successively the energy consumption. However, the chlorine-alkali industry is still one of the biggest electricity consumers in the whole world. With the application of oxygen-consuming gas-diffusion electrodes as a cathode, the energy consumption can be theoretically diminished once more with 30%. If this 30% of energy savings due to the use of gas-diffusion electrodes (GDE) can be accomplished, it is evident that at the same time the amount of CO2 gas emitted in the environment shall be reduced. The basis of the present elaboration is formed by the galvanostatic current interruption measurements, obtained in an experimental way, investigation of the applied gas-diffusion electrode?s working systems and contribution to the forthcoming elaborations of the electrode?s development.Chapter 2 concerns the theoretical background of the chlorine-alkali electrolysis. It investigates the production of chlorine and caustic soda in the world and presents information about the production process itself.Chapter 3 concerns the cell voltage and its contribution. In the second part of this chapter there is discussed the galvanostatic current interruption technique in both electrochemical cell and fuel cell.Under the title of characterisation of interruption measurement Chapter 4 deals with the application of the used method of experiments. Furthermore, it offers knowledge about the experimental setup. Chapter 5 is related to information on evaluation of the experiment and interpretation of the results, obtained in this experimental way. It is submitted an explanation of the variations of the GDE by the help of the current interruption method. Chapter 6 offers a general assessment of the results and clarifies the points that should be necessarily investigated in future elaborations.Since the work presented here was performed in a wider collaboration with partners from industry, the relevant figures, obtained results and structural layout of the GDEs and its changes are not discussed in the present master thesis due to the privacy of the project