PRODUCTION PROCESS of Electrochlorinator

ELECTRO CHLORINATOR (On-Site Sodium Hypochlorite Generator)

Electrochlorinator requires only salt, water and electricity. Electro chlorinator Provides the power of Chlorine without the danger of storing or handling hazardous materials. Sodium hypochlorite generated on-site does not degrade like commercial sodium hypochlorite. The total operating cost of Electrochlorinator is less than the conventional Chlorination methods. On-site generation of sodium hypochlorite allows the operator to produce only what is needed and when it is needed.

 

Pristine Water Electro-Chlorinator is a disinfection alternative that small water treatment systems will find beneficial because it is cost-effective, easy to produce and eliminates potentially dangerous handling and storage problems associated with other types of disinfection practices. On-site Sodium Hypochlorite (NaOCl) generation requires only salt, water and electricity to produce sodium hypochlorite actually needed. Unlike conventional 12 to 15 percent purchased hypochlorite, which will degrade over a course of time, Sodium Hypochlorite generated on-site will maintain its strength. Within the Electrolyzer, the brine solution- which is a good conductor of electricity- supports a current applied between the positive and negative electrodes, thus electrolyzing the sodium chloride solution. This results in chlorine (Cl2) gas being produced at the positive electrode (anode), while sodium hydroxide (NaOH) and hydrogen (H2) gas is produced at the negative electrode (cathode). The chlorine further reacts with the hydroxide to form sodium hypochlorite (NaOCl). This reaction can be simplified in the following manner:

NaCl (Salt) + H2O (Water) + Electricity = NaOCL (Sodium Hypochlorite) + H2 (Hydrogen)

In the process of on-site Sodium Hypochlorite generation 1 kg of equivalent chlorine can be generated from 4.5 kg of salt and 4 kilowatt hours of electricity. The final solution consists of approximately 0.8 percent sodium hypochlorite.

    Advantages of On-Site Generation of Sodium Hypochlorite

Although the economic consideration is the major advantage in using On- site generated Sodium Hypochlorite over the use of other forms of Chlorination, but the technical advantages are even greater.
The following are some of the problems associated with using commercial grade liquid sodium hypochlorite. These have high concentration (10-12%) of active chlorine. These are produced by bubbling gas chlorine in Caustic soda (Sodium Hydroxide). They are also commonly called as Liquid Chlorine.

Corrosion

The corrosion due to Commercially produced hypochlorite is a concern because of its effect on equipment. A 10 to 15% hypochlorite solution is very aggressive due to its high pH and chlorine concentration. Because of its aggressive nature, the hypochlorite solution will exploit any weakened areas in the hypochlorite piping system and may cause leaks.

Scaling

The formation of calcium carbonate scale is another concern when using commercial grade liquid hypochlorite for chlorination. Commercial grade liquid hypochlorite has a high pH. When the high pH hypochlorite solution is mixed with the dilution water, it raises the pH of the mixed water to above 9. The calcium in the water will react and precipitate out as calcium carbonate scale. Items such as pipes, valves and rotameters may scale up and no longer function properly. It is recommended that the commercial grade liquid hypochlorite not be diluted and that the smallest pipe lines, the flow rate will allow, should be used in the system.

Gas Production

Another concern with commercial grade hypochlorite is gas production. Hypochlorite loses strength over time and generates oxygen gas as it decomposes. The rate of decomposition increases with concentration, temperature, and metal catalysts.

Personal Safety

A small leak in the hypochlorite feed lines would result in the evaporation of the water and in turn the release of chlorine gas.

Chlorate Formation

The final area of concern is the possibility of chlorate ion formation. Sodium hypochlorite degrades over time to form the chlorate ion (ClO3-) and oxygen (O2). The degradation of the hypochlorite solution is dependent on the strength of the solution, temperature, and the presence of metal catalysts.
Decomposition of Commercial Sodium Hypochlorite can be created by two major ways:
a). The formation of Chlorates due to high pH, 3NaOCl= 2NaOCl+NaClO3.
b). Chlorine evaporation loss due to temperature increase.
Therefore, for any given strength and temperature, over a period of time, the higher strength product will eventually be lower in available chlorine strength than the lower strength product, since its decomposition rate is greater. The American Water Works Association Research Foundation's (AWWARF) concluded that the decomposition of concentrated bleach (NaOCl) is the most probable source of chlorate production. High concentration of Chlorate is not advisable in drinking water.

   Chlorine Comparison Chart  

Product Form	PH Stability	Available Chlorine	Form
C12 gas	Low	100%	Gas
Sodium hypochlorite(Commercial)	13+	5-10%	Liquid
Calcium hypochlorite granular	11.5	20%	Dry
Sodium hypochlorite(On-site)	8.7-9	0.8-1%	Liquid

Now which is the ideal disinfectant?

a. Chlorine Gas—this is too dangerous to handle and not safe in residential areas. Most of the times, they are not available.

b. Bleaching Powder—or Calcium Hypochlorite is effective, but the whole process of mixing, settling and disposing off of the sludge is very messy and cumbersome. This makes the whole area dirty. More over, the bleaching powder absorbs moisture during monsoon or in wet surroundings and emits chlorine gas, making the bleaching power lose its strength.

c. Liquid Bleach—or Liquid Chlorine -or Sodium Hypochlorite is very effective. This is in liquid form so very easy to handle. But the commercially available Liquid Chlorine is not only expensive but looses its strength over a period of time and becomes water. The danger of spillage is a common problem.

d. Electro Chlorinator—Very effective, very economical, very safe, and easy to prepare and use. Latest technology.