Electrolytic Ozone Generators ELOGs

The cell anode and cathode spaces are separated by a solid-state electrolyte membrane. The anode is made of a porous, water-penetrable and current-conductive carrier material coated with an active layer. At the site where the active catalytic layer and the electrolyte membrane touch ozone is produced when a direct current of 3 to 6 V at currents of up to 50 A (corresponding with a current intensity of 0.2 to 3.0 A cm-2) are applied (Fischer, 1997). 

The temperature of the liquid in the system should be kept below TL = 30 °C because of the possibility of fast ozone decay at higher temperatures. This also requires considerably high flow rates of purified feed water to be directed through the cell, unless the cell is air cooled or the feed water is cooled before entering the ELOG. 

The fact that dissolved ozone is produced brings a very important advantage to subsequent ozone applications mass transfer from the gas to liquid phase is not required. Efficient mixing (e. g. with static mixers) of the ozone-rich pure water stream with the (waste-)water stream to be treated, though, is required. During this in-situ ozone production, the liquid ozone concentration (cL) can easily reach the solubility level (cr ), depending on the pressure (P) and temperature (T) in the cell. Oversaturation of the feed-water will immediately occur, when the pressure drops. Due to this potential degassing, vent ozone gas destruction is also required for this system. 

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In the electrolytic ozone generator (ELOG) ozone is produced from the electrolysis of high purity water (Figure 2-4). In the electrolytic cell, water is split into molecular hydrogen H2... 

Figure 2-4 Working principle of the Electrolytic Ozone Generator (ELOG) (after Fischer, 1997).

Figure 2-5 Dependency of the ozone production capacity in an electrolytic ozone generator (ELOG) on the applied voltage and current (with cell temperature as a parameter) (from Fischer, 1997).

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