Method of operating an electrolysis cell

Claim 1

The method of reducing the caustic film concentration on the cathode side of the diaphragms of electrolysis cells having an anode compartment, a cathode compartment, an anolyte in the anode compartment, a catholyte in the cathode compartment, a diaphragm separating said compartments, screen anodes and cathodes in said compartments, and means to conduct an electrolysis current to said anodes and from said cathodes, which comprises maintaining a volume of anolyte in the anode compartment larger than the volume of anolyte in the gap between the anode and cathode, circulating anolyte through said screen anodes and out of said cells, passing an electrolysis current between said anodes and cathodes, introducing steam into the cathode compartment, maintaining the anode compartment below the condensation temperature of the steam in the cathode compartment under steady state operation throughout the electrolysis process by said circulation, condensing steam on the cathode side of the diaphragms, dripping the condensate and the caustic film removed from the cathode side of the diaphragms into the bottom of the cathode compartment and recovering the catholyte liquor.

Claim 2

The method of reducing the caustic film concentration on the cathode side of the diaphragms of electrolysis cells having an anode compartment, a cathode compartment, an anolyte in the anode compartment, a catholyte in the cathode compartment, a diaphragm separating said compartments, screen anodes and cathodes in said compartments, and means to conduct an electrolysis current to said anodes and from said cathodes, which comprises maintaining a volume of anolyte in the anode compartment larger than the volume of anolyte in the gap between the anode and cathode, circulating anolyte through said screen anodes and out of said cells, passing an electrolysis current between said anodes and cathodes, introducing steam into the cathode compartment, maintaining the anode compartment below the condensation temperature of the steam in the cathode compartment under steady state operation throughout the electrolysis process by said circulation, condensing steam on the cathode side of the diaphragms, dripping the condensate and the caustic film removed from the cathode side of the diaphragms into the bottom of the cathode compartment and recovering the catholyte liquor.

Claim 8

The method of reducing caustic film concentration on the cathode side of the diaphragms and of increasing the concentration of the caustic produced in diaphragm electrolysis cells having an anode compartment with a hollow screen anode therein, a cathode compartment with a hollow screen cathode therein, a diaphragm separating said compartment, an anolyte in the anode compartment, a catholyte in the cathode compartment and means to pass an electrolysis current between said anode and said cathode, which comprises maintaining a volume of anolyte in the anolyte compartment several times larger than the volume of anolyte between the anode and cathode, passing anolyte through the hollow screen anode, passing anodic gases upward through the hollow screen anode and out of said cell while circulating anolyte into said cell through said hollow screen anode and out of said cell, condensing water on the cathode side of the diaphragms above the catholyte liquor level by maintaining the anode compartment below the temperature at which steam condenses to water during the electrolysis by said anolyte circulation, allowing the condensate to flow into the bottom of the cathode compartments and recovering the catholyte liquor so produced.

Claim 9

The method of reducing caustic film concentration on the cathode side of the diaphragms and of increasing the concentration of the caustic produced in diaphragm electrolysis cells having an anode compartment with a hollow screen anode therein, a cathode compartment with a hollow screen cathode therein, a diaphragm separating said compartment, an anolyte in the anode compartment, a catholyte in the cathode compartment and means to pass an electrolysis current between said anode and said cathode, which comprises maintaining a volume of anolyte in the anolyte compartment several times larger than the volume of anolyte between the anode and cathode, passing anolyte through the hollow screen anode, passing anodic gases upward through the hollow screen anode and out of said cell while circulating anolyte into said cell through said hollow screen anode and out of said cell, condensing water on the cathode side of the diaphragms above the catholyte liquor level by maintaining the anode compartment below the temperature at which steam condenses to water during the electrolysis by said anolyte circulation, allowing the condensate to flow into the bottom of the cathode compartments and recovering the catholyte liquor so produced.

Claim 10

The method of reducing the caustic film concentration on the cathode side of the diaphragms and of increasing the concentration of the caustic produced in diaphragm electrolysis cells having an anode compartment with a hollow screen anode therein, a cathode compartment with a hollow screen cathode therein, a diaphragm separating said compartments, an anolyte in the anode compartment, a catholyte in the cathode compartment and means to pass an electrolysis current between said anode and said cathode, which comprises maintaining the catholyte chamber and the catholyte therein at a higher temperature than the anolyte chamber and the anolyte therein, passing anolyte through the hollow screen anode, passing anodic gases upward through the hollow screen anode and out of said cell while circulating anolyte into said cell through said hollow screen anode and out of said cell, condensing water on the diaphragm side of the cathodes by said temperature differential, caused by said anolyte circulation, to dilute and remove the caustic film on the diaphragm side of the cathodes, and recovering the caustic liquor so produced.

Claim 11

The method of reducing the caustic film concentration on the cathode side of the diaphragms and of increasing the concentration of the caustic produced in diaphragm electrolysis cells having an anode compartment with a hollow screen anode therein, a cathode compartment with a hollow screen cathode therein, a diaphragm separating said compartments, an anolyte in the anode compartment, a catholyte in the cathode compartment and means to pass an electrolysis current between said anode and said cathode, which comprises maintaining the catholyte chamber and the catholyte therein at a higher temperature than the anolyte chamber and the anolyte therein, passing anolyte through the hollow screen anode, passing anodic gases upward through the hollow screen anode and out of said cell while circulating anolyte into said cell through said hollow screen anode and out of said cell, condensing water on the diaphragm side of the cathodes by said temperature differential, caused by said anolyte circulation, to dilute and remove the caustic film on the diaphragm side of the cathodes, and recovering the caustic liquor so produced.

Claim 12

The method of diluting and renewing the aqueous cathodic film on the diaphragm side of the cathodes in diaphragm electrolysis cells having hollow screen anodes, which comprises maintaining a volume of anolyte in the anolyte compartment several times larger than the volume of anolyte between the anode and cathode, passing anolyte liquor through the hollow screen anodes, passing anodic gases through the hollow screen anodes and out of said cells, circulating anolyte liquor through said hollow screen anodes and out of said cells and condensing steam on the diaphragm side of the cathodes by maintaining the circulating anolyte temperature constantly below the temperature of the diaphragm side of the cathodes under steady state operation, dripping the condensate and removed film from the cathode side of the diaphragms into a catholyte pool in the bottom of the catholyte compartment, and recovering the catholyte liquor so produced.

Claim 13

The method of diluting and renewing the aqueous cathodic film on the diaphragm side of the cathodes in diaphragm electrolysis cells having hollow screen anodes, which comprises maintaining a volume of anolyte in the anolyte compartment several times larger than the volume of anolyte between the anode and cathode, passing anolyte liquor through the hollow screen anodes, passing anodic gases through the hollow screen anodes and out of said cells, circulating anolyte liquor through said hollow screen anodes and out of said cells and condensing steam on the diaphragm side of the cathodes by maintaining the circulating anolyte temperature constantly below the temperature of the diaphragm side of the cathodes under steady state operation, dripping the condensate and removed film from the cathode side of the diaphragms into a catholyte pool in the bottom of the catholyte compartment, and recovering the catholyte liquor so produced.

Claim 14

The method of diluting and renewing the aqueous cathodic film on the diaphragm side of the cathodes in diaphragm electrolysis cells having hollow screen anodes and hollow screen cathodes therein and of increasing the strength of the catholyte liquor produced, which comprises constantly maintaining the catholyte chamber and the catholyte therein at a higher temperature than the anolyte chamber and the anolyte therein by circulating anolyte liquor through said hollow screen anodes and out of said cells, cooling said anolyte liquor and the anolyte chamber by said circulation, condensing water on the surfaces of the cathodes by said temperature differential to dilute the cathodic film on the cathode side of the diaphragms, flowing the condensate and removed cathodic film from the cathode side of the diaphragms and recovering the catholyte liquor so produced.

Claim 15

The method of diluting and renewing the aqueous cathodic film on the diaphragm side of the cathodes in diaphragm electrolysis cells having hollow screen anodes and hollow screen cathodes therein and of increasing the strength of the catholyte liquor produced, which comprises constantly maintaining the catholyte chamber and the catholyte therein at a higher temperature than the anolyte chamber and the anolyte therein by circulating anolyte liquor through said hollow screen anodes and out of said cells, cooling said anolyte liquor and the anolyte chamber by said circulation, condensing water on the surfaces of the cathodes by said temperature differential to dilute the cathodic film on the cathode side of the diaphragms, flowing the condensate and removed cathodic film from the cathode side of the diaphragms and recovering the catholyte liquor so produced.

Claim 16

The method of conducting electrolysis in an alkali halide cell having an anode compartment containing a screen anode and a brine anolyte, a cathode compartment containing a cathode screen and a diaphragm between the anode and the cathode in contact with the cathode screen, which comprises circulating anolyte through said screen anode and out of said cell, conducting the electrolysis between the anode and the cathode, maintaining the level of catholyte in the cathode compartment low enough to provide a gas space in the cathode compartment adjacent to the cathode screen, supplying water vapor to said space during said electrolysis and maintaining the temperature of the anolyte in contact with the diaphragm at least 12° C below the catholyte temperature, to condense water from said vapor on the cathode during steady state operation of said cell.

Claim 17

The method of conducting electrolysis in an alkali halide cell having an anode compartment containing a screen anode and a brine anolyte, a cathode compartment containing a cathode screen and a diaphragm between the anode and the cathode in contact with the cathode screen, which comprises circulating anolyte through said screen anode and out of said cell, conducting the electrolysis between the anode and the cathode, maintaining the level of catholyte in the cathode compartment low enough to provide a gas space in the cathode compartment adjacent to the cathode screen, supplying water vapor to said space during said electrolysis and maintaining the temperature of the anolyte in contact with the diaphragm at least 12° C below the catholyte temperature, to condense water from said vapor on the cathode during steady state operation of said cell.