De Nora Balpure general manager Dr Stelios Kyriacou feels that there are misconceptions among owners when choosing a ballast water management system (BWMS) for large vessels such as tankers.
“Hazardous area tanker installations, which can be challenging for some suppliers, is a core area of expertise for us. At a time when shipowners are seeking practical, unbiased information, we want to address three common misconceptions in relation to chlorine, hydrogen, and system configuration,” he said.
According to Dr Kyriacou the presence of chlorine is often mistaken for chlorine gas.
The general manager of De Nora feels that the term electrochlorination may suggest the presence of chlorine. The process involves the generation of sodium hypochlorite, which is a diluted bleach, not chlorine gas.
Household bleach is a hypochlorite solution varying from 5.25 up to 8.25% concentration, while sterilising solutions used for babies’ bottles are available in 1 and 2% strengths. Seawater electrochlorination systems produce a maximum of 1.5%.
“To sum it up, when it comes to chlorine, electrochlorination systems produce a biocide in a concentration just a little more than is used to clean a baby’s bottle!” said Dr Kyriacou.
Hydrogen is regarded by many as an explosive gas, but De Nora pointed out that the Balpure technology proprietary control system incorporates intelligent controls with a safety bias and this includes an inline gas separator which ensures the safe removal of hydrogen from the liquid stream before the treated water reaches any ballast tank thus eliminating any risk of trapped hydrogen gas in the head space of ballast tanks.
With regards to configuration, De Nora Balpure is a slip stream system (a small portion of ballast water is diverted for treatment and fed as concentrate into the ballast tanks).
Full flow design versus slip stream design
According to Dr Kyriacou “Slip stream electrochlorination is superior to UV and full flow electrolysis BWMS since all such systems install major treatment components within the hazardous zone. Such components include UV reactors and electrochemical cells, both connected by high power electrical cables to their respective power supplies. The bottom line is that, when it comes to safety, certain electrochlorination BWMS are far better suited to vessels with large flows and hazardous zones.”