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.

1 . A process for producing a hypochlorite solution in an electrolytic cell comprising: 
 (a) forming an aqueous based chloride solution with a chloride salt;    (b) controlling the concentration of chloride within the solution to an amount comprising less than 20 g/L chloride salt;    (c) piping the salt solution from step (a) 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;    (d) allowing the chloride solution to contact the anode;    (e) allowing the chloride solution to contact the cathode;    (f) passing an electric current throughout the electrolytic cell to produce hypochlorite; and    (g) controlling the electric current so that the power consumption is less than 2.3 kWh per pound of hypochlorite produced;    wherein the cell efficiency comprises less than 2.5 kg of chloride salt consumed for every 1 kg of hypochlorite generated.    
   
   
       2 . The process for producing a hypochlorite solution of  claim 1  wherein the salt solution comprises sodium chloride, the amount of sodium chloride consumed during the method comprising less than 2.5 kg for every 1 kg of hypochlorite generated.  
   
   
       3 . The process of  claim 1  wherein the metallic base material is selected from a group comprising titanium, iron, steel, copper and nickel alloys, and the first coating comprises an oxide of the metallic base material.  
   
   
       4 . The process of  claim 1  wherein the second coating comprises a non-conductive ceramic selected from a group comprising yttria-stabilized zirconia, zirconia, titania, chromia and hastelloy.  
   
   
       5 . The process of  claim 1  wherein the current efficiency is greater than 70%.  
   
   
       6 . The process of  claim 1  wherein the temperature of the solution is maintained within a range of about 15° C. to less than 60° C.  
   
   
       7 . A process for producing a hypochlorite solution in an electrolytic cell comprising: 
 (a) forming an aqueous based chloride solution with a chloride salt;    (b) controlling the concentration of chloride within the solution to an amount comprising less than 20 g/L chloride salt;    (c) piping the salt solution from step (a) to the electrolytic cell, the electrolytic cell comprising an anode and a cathode, the cathode comprising a metallic base selected from a group comprising titanium, iron, steel, copper and nickel alloys, a first coating on the metallic base comprising an oxide of the metallic base material, and a second coating on the oxide of the metallic base material comprising a non-conductive ceramic;    (d) allowing the chloride solution to contact the anode;    (e) allowing the chloride solution to contact the cathode;    (f) passing an electric current throughout the electrolytic cell to produce hypochlorite; and    (g) controlling the electric current so that the power consumption is within a range of about 1.8 kWh per pound of hypochlorite produced to about 2.5 kWh per pound of hypochlorite produced;    wherein the cell efficiency comprises less than 2.5 kg of chloride salt for every 1 kg of hypochlorite generated and the current efficiency is maintained at greater than 70%.    
   
   
       8 . The process of  claim 7  wherein the chloride solution comprises less than 20 g/L chloride salt  
   
   
       9 . The process of  claim 7  wherein the chloride salt is selected from sodium chloride or potassium chloride.  
   
   
       10 . A process for producing a hypochlorite solution in an electrolytic cell comprising: 
 (a) forming an aqueous based sodium chloride solution;    (b) piping the sodium chloride solution formed in step (a) to the electrolytic cell, the electrolytic cell comprising an anode and a cathode, the cathode comprising a titanium base for conducting electrons, a first coating on the titanium base, the first coating comprising titanium oxide, and a non-conductive yttria-stabilized zirconia second coating applied to the titanium first coating;    (c) allowing the chloride solution to contact the anode;    (d) allowing the chloride solution to contact the cathode;    (e) passing an electric current from the anode through the solution to the cathode to produce hypochlorite;    (f) controlling the electric current so that power consumption is within a range of about 1.5 kWh per pound of hypochlorite produced to about 2.0 kWh per pound of hypochlorite produced; and    (g) maintaining the temperature within a range of about 15° C. to about 60° C.;    wherein the cell efficiency comprises less than 2.5 kg of chloride salt consumed for every 1 kg of hypochlorite generated and the current efficiency is maintained at greater than 70%.    
   
   
       11 . The process of  claim 10  wherein the chloride solution comprises less than 25 g/L chloride salt  
   
   
       12 . A process for producing a hypochlorite solution in an electrolytic cell comprising: 
 (a) forming an aqueous based chloride solution with a chloride salt, the chloride solution comprising an amount greater than 25 g/L chloride salt,    (b) piping the salt solution from step (a) to the electrolytic cell, the electrolytic cell comprising an anode and a cathode, the cathode comprising a metallic base selected from a group comprising titanium, iron, steel, copper and nickel alloys, a first coating on the metallic base comprises an oxide of the metallic base material, and a second coating on the oxide of the metallic base material comprising a non-conductive ceramic;    (c) allowing the chloride solution to contact the anode;    (d) allowing the chloride solution to contact-the cathode;    (e) passing an electric current throughout the electrolytic cell to produce hypochlorite; and    (f) controlling the power consumption within an amount comprising less than 2.0 kWh per pound of hypochlorite produced;    wherein the cell efficiency comprises less than 3.0 kg of chloride salt consumed for every 1 kg of hypochlorite generated and the current efficiency is maintained at greater than 80%.    
   
   
       13 . A process for producing a hypochlorite solution in an electrolytic cell comprising: 
 (a) forming an aqueous based sodium chloride solution, the chloride solution comprising less than 20 g/L chloride salt;    (b) piping the sodium chloride solution formed in step (a) to the electrolytic cell, the electrolytic cell comprising an anode and a cathode, the cathode comprising a titanium base for conducting electrons, a first coating on the titanium base, the first coating comprising titanium oxide, and a non-conductive yttria-stabilized zirconia second coating applied to the titanium first coating;    (c) allowing the chloride solution to contact the anode;    (d) allowing the chloride solution to contact the cathode;    (e) passing an electric current from the anode through the solution to the cathode to produce hypochlorite;    (f) controlling the power consumption so that the amount of electrical power consumed comprises less than 2.0 kWh per pound of hypochlorite produced; and    (g) maintaining the temperature within a range of about 15° C. to about60° C.;    wherein the cell efficiency comprises less than 2.5 kg of chloride salt consumed for every 1 kg of hypochlorite generated and the current efficiency is maintained at greater than 70%.