Sodium hypochlorite (NaOCl) is produced by direct reaction of chlorine gas with caustic soda solution from chlor-alkali process, producing a water solution at approx. 150 g/l concentration, commonly known as bleach, to be used for water treatment, for bleaching agent in textile industry and for household products.
Consito developed know-how and technologies for small sclae sodium hypochlorite units, 3.5 to 30 m3/day sodium hypochlorite solution capacity, up to approx. 160 g/l concentration and approx. 150 g/l available chlorine, in order to provide for a reliable, highly efficient device to produce "on site" bleach.
The need of sodium hypochlorite solutions to substitute gaseous chlorine for chlorination is highly increasing due to the strict regulations related to the liquid chlorine transportation and storage as well as the public concern over the use of gaseous chlorine.
The use of bleach is becoming a widespread usage being the on-site production and storage not affected by above mentioned regulations.
Our small scale plants, named HYPO-PACK, are pre-assembled, modular skid-mounted reaction units. Usually, this package is supplied together with a CHLOR-PACK® unit in order to produce sodium hypochlorite starting from sodium chloride as raw material.
Bleach can be fed directly by pipeline to the consumers or bottled.
Sodium hypochlorite solution is produced by direct reaction of chlorine gas with caustic soda solution, according to reaction:
Chlorination reaction is performed by absorbing in a 18% max caustic soda solution, the chlorine from electrolysis process, e.g. CHLOR-PACK®, or from cylinders.
The absorbing operation is effected in three stages, each provided with a recycling pump.
Chilled water coolers, installed on recycle solution, dissipate heat of reaction and avoid sodium chlorate formation.
Fresh caustic solution, flows countercurrent to chlorine gas.
Sodium hypochlorite solution is sent to storage from first vessel, where the concentration of available chlorine is continuously controlled by a redox meter.
Raw materials are chlorine gas (Cl2) and caustic soda (NaOH) solution from chlor-alkali process or salt (NaCl) and water in case of supply together with the CHLOR-PACK® unit
The following HYPO-PACK operating data are referred to 1 metric ton of sodium hypochlorite solution (NaOCl) at 15.75% concentration, with 15% available chlorine and 1.15% excess caustic soda.
|Raw materials & utilities|
|Chlorine (as 100%)||kg||150|
|Caustic soda 18% solution (as 100%)||kg||170|
Sodium hypochlorite is employed as a disinfectant and deodorant in treating water supplies and sewage effluent, in swimming pools, dairies, and in the household.
It is used as a bleach in commercial and home laundries.
Soda bleach solutions are prepared in various strengths up to 16.5% NaOCl, but household bleach is limited to about 5.5%, because less excess caustic soda is required to maintain stability.
Sodium hypochlorite bleach is powerful bactericide against bacteria and viruses and it is widely, used for municipal drinking water disinfection, waste water treatment, swimming pool disinfection, bleach in textile industry, algae control in cooling water and in water basins.
In general, besides a wide range of applications, it is very effective weapon as general purposes disinfectant in homes, hospitals, farms etc.