Commercial tests of OIRTA-Pd anodes: efficiency
of sodium hypochlorite production

Summary

The results of long-term commercial tests (11 months, 7,211 operating hours) of palladium-containing OIRTA-Pd anodes are presented in comparison with the non-customized OIRTA anodes. The work objective was proving experimentally the efficiency and stability of the developed anodes in the production of sodium hypochlorite by electrolysis under real-life operating conditions. The tests were conducted in a UG-25MK-1000 electrolyzer with a capacity of 1,000 kg/day as active chlorine (Aleksandrovskii water supply system, Rostov-on-Don). During the tests, the voltage, current, active chlorine concentration, and solution temperature were regularly monitored, and the current output and specific energy consumption were calculated. OIRTA-Pd anodes were found to provide for a sustainable advantage over standard OIRTA anodes throughout their entire service life, i. e., a 4.6% reduction in operating voltage, a 10.4% increase in active chlorine concentration, a 10.4% increase in current output, a 14.6% reduction in specific energy consumption, and a 7.3% reduction in solution heating. For a plant with a capacity of 1,420 t/year as active chlorine, the annual energy savings from anode replacement amount to 326.6 MWh. The stability of the developed anodes has been proved throughout the entire testing period. The test results are recommended to the use while designing new electrolysis plants and upgrading the existing ones.

Key words

sodium hypochlorite , electrolysis , energy efficiency , water disinfection , specific power consumption , corrosion resistance , OIRTA-Pd , mixed metal oxide electrodes , palladium-containing anodes , current output