Sodium Hypochlorite Plant (also known as the Waste Air De-chlorination, WAD Section) is an Integral part / statutory requirement for any of Chlor-alkali plant for Absorption of Chlorine in Waste Air or as part of process requirement.A professional design scheme will make the operation of chlor-alkali plant more stable and reduce the frequency of failures during plant start-up or change over, even untrained operator can be run the system smoothly.
NaOCl Production Unit For Chlor-alkali Plant
KALF able to design and supply of NaOCl facility to produced NaOCl at 10%-13% concentration from both membrane electrolyser and Mono-polar Diaphragm cell.
Sodium hypochlorite from membrane electrolyser more for higher capacity of plant,The most common chlor-alkali process involves the electrolysis of aqueous sodium chloreide (Saturated brine solution) in a membrance electrolyser.
Saturated brine is passed into the first chamber of the cell where the chloride ions are oxidised at the anode, losing electrons to become chlorine gas:
2Cl− → Cl2 + 2e−
At the cathode, positive hydrogen ions pulled from water molecules are reduced by the electrons provided by the electrolytic current, to hydrogen gas, releasing hydroxide ions into the solution:
2H2O + 2e− → H2 + 2OH−
The ion-permeable ion exchange membrane at the center of the cell allows the sodium ions (Na+) to pass to the second chamber where they react with the hydroxide ions to produce caustic soda (NaOH) as following:
2NaCl + 2H2O → Cl2 + H2 + 2NaOH
A membrane cell is used to prevent the reaction between the chlorine and hydroxide ions. If this reaction were to occur the chlorine would be disproportionated to form chloride and hypochlorite ions:
Cl2 + 2OH− → Cl− + ClO− + H2O
Above about 60 °C,chlorate can be formed:
3Cl2 + 6OH− → 5Cl− + ClO3− + 3H2O
Note: Because of the corrosive nature of chlorine production, the anode (where the chlorine is formed) must be made from a non-reactive metal such as titanium, whereas the cathode (where hydroxide forms) can be made from a more easily oxidized metal such as nickel.