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Name
INEOS Chlor-Alkali Technology
Owner
/ Ineos Technologies Ltd.
Brand
Technology is registered for Trademark BICHLOR™ membrane electrolyser system
Process
Decompositions reactions
Type
Chlor-Alkali Process
Available
Description

INEOS' chlor-alkali technology is rooted in its BICHLOR™ membrane electrolyser system, a refinement of industrial electrolysis methods developed over 130 years. Here's a detailed technical breakdown:

Core Technology Origins

  • Legacy foundation: Inherited infrastructure from ICI's 1897 Weston Point facility (UK), operational for over a century.
  • Process evolution: Transitioned from mercury/diaphragm cells (phased out due to environmental concerns) to modern membrane technology.
  • Key acquisitions: Expertise consolidated through historical assets, including ICI's electrolysis patents and operational know-how.

Technical Configuration

  • Modular membrane cells:
    • Each module contains anode/membrane/cathode assemblies in a "zero-gap" design to minimize voltage loss.
    • Titanium anode pans with mixed metal oxide (MMO) coatings resist chlorine corrosion.
    • Nickel cathode pans with catalytic coatings enhance hydrogen evolution.
  • Membrane materials: Fluorinated polymer cation-exchange membranes (e.g., Nafion™ derivatives) enable selective Na⁺ ion transfer.
  • Pressure management: Operates at 0–400 mbarg via reinforced pan walls (1mm thickness vs. 0.8mm in competitors).

Performance Metrics

Parameter Specification
Energy consumption <1,990 kWh/tonne NaOH @ 6 kA/m²
Current density Up to 7 kA/m²
Annual NaOH output 52,000–69,000 tonnes per electrolyser
Coating lifespan 16 years (cathode), 8–12 years (anode)
System lifespan 30+ years with in-house recoating

Operational Advantages

  1. Maintenance efficiency:
    • Individual modules replaceable without full shutdowns.
    • External headers isolate hydrogen (cathode) and chlorine (anode) streams.
  2. Safety features:
    • Fully wetted membranes prevent gas crossover and explosions.
    • Leak-resistant bolted seals on modules.
  3. Material innovations:
    • Explosion-bonded titanium/nickel discs ensure electrical conductivity.
    • MMO anode coatings reduce chlorate byproduct formation.

Industrial Process Workflow

1. Brine Purification (ICI Legacy)

  • Devices:
    • Dissolution tanks: Raw salt (NaCl) dissolved in water to form brine (25–28% NaCl)
    • Ion exchange columns: Removal of Ca²⁺, Mg²⁺, and heavy metals via chelating resins (ICI-developed process)
    • Settling tanks: Clarification to remove suspended solids

2. Brine electrolysis (BICHLOR™ Core):

  • Modular cell design (ICI’s bipolar electrolyser patents → INEOS BICHLOR™):
    • Anode pan: Titanium substrate with mixed metal oxide (MMO) coating for chlorine evolution
    • Cathode pan: Nickel substrate with catalytic coating (16-year lifespan) for hydrogen evolution.
    • Cation-exchange membrane: Fluoropolymer-based (e.g., Nafion™) separating anode/cathode chambers.
    • Zero-gap configuration: Electrodes pressed directly against the membrane to minimize voltage drop.
  • Process flow:
    1. Purified brine enters anode chamber via feed tubes, fully wetting the membrane.
    2. DC current (6–7 kA/m²) splits NaCl into Cl₂ (anode) and H₂ + NaOH (cathode):
      2NaCl + 2H₂O → Cl₂ + H₂ + 2NaOH
    3. Chlorine gas rises to anode chamber header; hydrogen and 32% NaOH catholyte exit cathode chamber.

3. Gas-Liquid Separation

  • Anode side (Cl₂ handling):
    • Dechlorination towers: Stripping residual Cl₂ from depleted brine using vacuum or air.
    • Coolers/compressors: Chlorine gas cooled to 15–20°C for liquefaction or chemical synthesis.
  • Cathode side (H₂/NaOH handling):
    • Gas separators: Hydrogen purified via catalytic recombination (O₂ removal) for fuel or ammonia production.
    • Evaporators: NaOH concentrated to 50% using multi-effect evaporation.

4. Product Finishing (ICI/INEOS Methods)

  • Chlorine derivatives:
    • HCl synthesis: Combustion of H₂ and Cl₂ in quartz burners.
    • NaClO production: Absorption of Cl₂ in NaOH solution.​​​​​​​
  • Caustic soda:
    • Crystallizers: Solid NaOH flakes/prills via cooling and drying.

References

  1. INEOS Group > Electrochemical Solutions > The Chlor-Alkali Process. (Accessed 23rd May 2025) 
  2. INEOS Group > Electrochemical Solutions > Modular Membrane Cell Electrolysers. (Accessed 23rd May 2025) 
  3. INEOS Group > Electrochemical Solutions > INEOS Electrochemical Solutions. (Accessed 23rd May 2025)
  4. INEOS Group > Electrochemical Solutions > BICHLOR™ ELECTROLYSER brochure. (Accessed 23rd May 2025) 
  5. CloroSur, Technical Seminar, 18th Nov 2014, CHLOR-ALKALI TECHNOLOGY, INEOS Technology.
Link
System Info

Updated by
UserPic  Kokel, Nicolas
Updated
5/23/2025 9:23 AM
Added by
UserPic  Kokel, Nicolas
Added
5/23/2025 7:08 AM
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