Chlorine dioxide is a highly explosive and flammable gas in standard conditions. Therefore, its handling and storing is subject to very rigorous conditions.
Chlorine dioxide solution is also not stable enough to be stored for a long time. Hence, using it as gas and solution is not practically possible. As a result, the best way to deal with it is to produce it in-situ. For this purpose, chloride dioxide injection systems are used. The heart of these systems is a catalyst reactor to which reactants are injected through dosing pumps and the products, including, chlorine dioxide and salt, are injected into water after exiting the system.
The reactants are normally sodium chlorite and a strong acid like HCl. The reaction in the reactor of this system is as follows:
5 NaClO2 + 4HCl → 4 ClO2 + 5 NaCl + 2 H2O
Common concentrations for sodium chlorite solution, based on EN938 standard are 31% and 25% weight percent solutions, that are produced by Niltech company and Hydrochloric acid is also used in concentrations of around 31-33 percent, which is easily available in the country.