{
  "patent_number": "US 9181624",
  "country": "US",
  "title": "Making Caustic Soda with Less Salt Using a Special Electrolysis Cell",
  "original_title": "Method of electrolysis employing two-chamber ion exchange membrane electrolytic cell having gas diffusion electrode",
  "summary": "This patent describes a method to make purer caustic soda and chlorine gas using a two-chamber electrolysis cell with a gas diffusion electrode by carefully controlling pressure differences.",
  "what_it_does": "The patent claims a method for electrolyzing brine (saltwater) in a \"two-chamber ion exchange membrane electrolytic cell\" (Claim 1). This cell has an \"anode chamber\" and a \"cathode gas chamber\" separated by an \"ion exchange membrane.\" The cathode chamber uses a \"gas diffusion electrode.\" The core idea is \"reducing a differential pressure\" between the liquid pressure in the anode chamber and the gas pressure in the cathode gas chamber (Claim 1). This pressure difference is precisely controlled, for example, reduced to \"2.4 kPa or less\" (Claim 1) or \"-21.6 kPa or more\" (Claim 2), by adjusting a \"sealing pot or a valve\" (Claim 1). This precise pressure control helps in \"decreasing a salt concentration in the caustic soda aqueous solution\" (Claim 1). For example, by carefully adjusting the valve downstream of the cathode chamber, the pressure inside the cathode chamber can be increased, which reduces the pressure difference across the membrane, leading to purer caustic soda.",
  "what_it_does_not_cover": [
    "Electrolysis methods that do not use a \"two-chamber ion exchange membrane electrolytic cell.\"",
    "Electrolysis cells that do not employ a \"gas diffusion electrode\" as the cathode.",
    "Methods that do not involve reducing the differential pressure between the anode liquid and cathode gas.",
    "Methods where the differential pressure is not controlled to be \"2.4 kPa or less\" or \"-21.6 kPa or more.\"",
    "Electrolysis processes for producing chemicals other than chlorine gas and caustic soda."
  ],
  "filed": "2010-04-15",
  "granted": "2015-11-10",
  "expires": "2030-04-15",
  "status": "active",
  "holder": "Chlorine Engineers Corp",
  "holder_url": "https://patentbrief.org/company/chlorine-engineers-corp",
  "inventors": [
    {
      "name": "Mikihito Sugiyama",
      "url": "https://patentbrief.org/inventor/mikihito-sugiyama"
    },
    {
      "name": "Kiyohito Asaumi",
      "url": "https://patentbrief.org/inventor/kiyohito-asaumi"
    },
    {
      "name": "Yukinori Iguchi",
      "url": "https://patentbrief.org/inventor/yukinori-iguchi"
    }
  ],
  "times_cited": 7,
  "tags": [
    "chemical_manufacturing",
    "energy",
    "materials",
    "industrial_processes"
  ],
  "abstract": "Disclosed is an electrolysis method, whereby sodium chloride concentration of an aqueous caustic soda solution formed through electrolysis in a two-chamber ion-exchange membrane sodium chloride electrolytic cell, which is equipped with a gas diffusion electrode as a cathode and divided into an anode chamber containing an anode and a cathode gas chamber containing the cathode that are partitioned by an ion-exchange membrane, is lowered. In a two-chamber ion-exchange membrane electrolytic cell ( 1 ) using a gas diffusion electrode ( 7 ), electrolysis is performed while reducing the pressure difference between the liquid pressure in the anode chamber and the gas pressure in the cathode gas chamber, i.e., the pressure calculated by subtracting [oxygen-containing gas pressure in cathode chamber (measured by manometer ( 18 ))] or [gas pressure at oxygen-containing gas inlet ( 14 )] from [(liquid pressure in anode chamber applied to ion-exchange membrane when anode chamber is filled up with aqueous sodium chloride solution) being equal to (depth of aqueous sodium chloride solution)(density of aqueous sodium chloride solution)/2].",
  "url": "https://patentbrief.org/patent/us/9181624/method-of-electrolysis-employing-two-chamber-ion-exchange-membrane-electrolytic-",
  "markdown_url": "https://patentbrief.org/patent/us/9181624/method-of-electrolysis-employing-two-chamber-ion-exchange-membrane-electrolytic-/md",
  "google_patents_url": "https://patents.google.com/patent/US9181624",
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