The best technology available
Bipolar technology (AZEC-B1 electrolysers) started being used in 2002, after an investment decision in 2000, to replace the old mercury electrolysers. All chlorine, hydrogen and caustic soda production at BONDALTI is now carried out using clean membrane technology, which still complies with the Best Available Technologies Reference documents - BREF (BAT reference documents) issued by the European IPPC Bureau for the chlor-alkali industry.
This decision to move from mercury technology, some 17 years before the ban on the use of mercury for chlorine production came into force, shows BONDALTI’s commitment to the environment, always choosing to apply and improve its processes, through selecting environmentally friendly alternatives and technologies.
The brine electrolysis section consists essentially of nine AZEC-B1 electrolysers and 14 MGC23 electrolysers. Purified brine from the Brine Treatment Section is fed to the anode compartment, where chlorine gas and diluted brine are produced.
In addition, caustic soda is fed to the cathode compartment of the electrolysers, in a controlled concentration, in order to produce caustic soda at approximately 32%. This caustic soda is subsequently sent to the Soda Concentration plant.
The nine state-of-the-art AZEC-B1 electrolysers are electrically connected in parallel and the complete circuit is operated at a controlled constant direct current rate in the rectifier. Each bipolar electrolyser has 62 cells, and the voltage of each element is carefully monitored using specific software, which allows BONDALTI to monitor any changes in voltage of the different elements thereby ensuring maximum equipment performance and safe electrolysis operation.
