🔧 Function of Anode Cells in CED Plants

• Provide the anode (usually titanium with an insoluble coating like MMO or platinized titanium).
• House the anolyte solution (usually a weak acid like formic or acetic acid).
• Use a membrane (ion exchange or porous) to prevent contamination of the paint bath.
• Remove excess acid generated during deposition.
• Help maintain pH and conductivity of the bath.
  
  🔍 Types of Anode Cells
  Anode cells come in several configurations based on design, material, and application. The most common types include:
  
  Type Description
• Flat Plate Anode Cell Flat membrane surface; ideal for compact tanks or limited space.
• Tubular Anode Cell Cylindrical design; provides larger membrane surface area and easier servicing.
• Basket Type Cell Used with replaceable anode baskets (e.g., for platinized titanium granules).
• Spiral Wound Cell Coiled configuration; used in small or confined systems.
• Immersible/External Can be directly immersed or kept externally in circulation loop.
  
  📐 Specifications of Anode Cells
• Parameter Typical Specification
• Anode Material Titanium substrate with MMO (Mixed Metal Oxide) or platinum coating
• Membrane Material Cation exchange membrane (e.g., Nafion, reinforced PTFE)
• Anolyte Formic Acid / Acetic Acid solution (0.5% to 2%)
• Operating Voltage 250 – 500 VDC (for CED line); local voltage depends on configuration
• Current Density 1 – 5 A/dm² (based on anode surface area)
• Operating Temperature 20°C – 35°C (room temperature to slightly elevated)
• Anode Cell Lifespan 1 – 3 years depending on usage, membrane fouling, and maintenance
• Membrane Area Varies: typically 0.5 – 2 m² per cell, depending on tank size and current requirements
• Cleaning Frequency Monthly to quarterly, depending on fouling level
  
  📦 Sample Anode Cell Design (Tubular Type)
• Component Material / Spec
• Outer Shell PVC / PP / SS316L
• Anode Rod MMO coated titanium rod (ø 25 mm typical)
• Membrane Tube Nafion or PTFE-reinforced ion exchange membrane
• Inlet/Outlet Anolyte circulation via acid-resistant tubing
• Seal EPDM or Viton
• Mounting Flange or clamp-on type
  
  🧪 Anolyte Circulation System (Typically Includes)
• Pump: Acid-resistant centrifugal pump (Teflon, PP, or PVDF)
• Reservoir: 100 – 500 L tank with acid level monitoring
• Chiller/Heater: Optional for temperature control
• Conductivity Control: For acid concentration monitoring
• pH Monitoring: Optional inline pH sensors
  
  ✅ Selection Criteria
• When selecting anode cells, consider:
• Bath size and current requirements
• Compatibility with coating material
• Type of anode material based on bath chemistry
• Ease of maintenance and membrane replacement
• System integration with the circulation and filtration system