Process for producing hypochlorite

Abstract

In a process for producing sodium hypochlorite in an electrolytic cell comprises forming an aqueous based chloride solution with a chloride salt; controlling the concentration of chloride within the solution to an amount comprising less than 25 g / L chloride salt; piping the salt solution to the electrolytic cell, the electrolytic cell comprising an anode and a cathode, the cathode comprising a metallic base material, a first coating on the metallic base material and a second non-conductive ceramic coating on the metallic base material. The chloride solution is then in contact with the anodes and cathodes and an electric current is sent throughout the electrolytic cell to produce hypochlorite. During this process the electric current is controlled so that the power consumption is less than 2.5 kWh per pound of hypochlorite produced and the resulting cell efficiency comprises less than 2.5 kg of chloride salt consumed for every 1 kg of hypochlorite generated.

Description

FIELD OF THE INVENTION [0001] This invention relates generally to a process for producing hypochlorite. More specifically, this invention relates to a process of electrolytic production of hypochlorite from salt containing chlorides in an aqueous solution. BACKGROUND OF THE INVENTION [0002] Chlorine in the form of hypochlorite was first used for disinfecting water systems in London after an outbreak of cholera in 1850. For the past century, chlorination has become the standard way to disinfect water supplies, potable water, wastewater, and swimming pools, to eliminate epidemic waterborne diseases. The traditional way to disinfect water with chlorine was through the use of chlorine gas. Transporting bulk chlorine on crowded highways and into residential areas has become a major safety concern since the transport of chlorine gas under high pressure can be very hazardous. Also, the transport of commercial hypochlorite, which is predominantly water, is very expensive. Stringent regulati...

AI Technical Summary

Benefits of technology

[0026] Reducing salt and power consumption as well as making the process of hypochlorite production more efficient with improved current efficiency is desired to reduce costs. The process of this invention generates hypochlorite, either in the form of sodium hypochlorite or potassium hypochlorite, in terms of available chlorine, more efficiently, that is with a reduction of feed product consumed or energy required to produce equivalent amounts of hypochlorite as previous methods. Increased efficiency is measured by an increase in the percentage of sodium or potassium chloride converted to hypochlorite during the electrolytic process and a decrease in power consumption.

[0027] Temperature can also affect the efficiency of the process. Higher temperatures of the solution during electrolysis and increased concentrations of available chlorine enhance the probability of a shift in kinetics to form undesirable by products. The amount of available chlorine, the desired end product, is reduced. Because of these side reactions, more sodium chloride and electric current must be consumed to produce an equal amount of available chlorine. Advantageously, during the process of this invention, the amount of chloride salt consumed during the electrolysis process is reduced while maintaining both cell efficiency and current efficiency. Side reactions are reduced thereby allowing greater production of available chlorine. The current efficiency of the process can be increased so that the current efficiency is within a range of from about 70% to about 80%. Improved efficiency translates to cost savings in terms of feed product and electric power consumption.

Problems solved by technology

Transporting bulk chlorine on crowded highways and into residential areas has become a major safety concern since the transport of chlorine gas under high pressure can be very hazardous.

Also, the transport of commercial hypochlorite, which is predominantly water, is very expensive.

Stringent regulation of toxic gasses and accidental releases of chlorine and higher costs have caused alternative sources for chlorine to be sought for water disinfection.

Problems that occur during the reaction affect the amount of hypochlorite produced, chlorate formation for example.

Problems that occur in the market place, such as the availability and cost of salt and electrical power, affect the economy of hypochlorite production.

Temperature can also affect the efficiency of the process.

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