SESPI Chloropure® Electrolyzer Overview

  • Low capital cost and low maintenance cost with maximum uptime
  • Low power consumption–high efficiency electrolytic design with fewer bus losses
  • Electrode pack contained within FRP housing – no leaks
  • Routine acid cleaning (once every 3-4 weeks) maintains optimum cell performance and electrode life with changing seawater feeds
  • Small layout footprint – horizontal or vertical
  • Ideal for large land-based applications such as power plants desalinations plants
  • Replacement of single electrode by an easy removal of entire electrode assembly
  • Hypochlorite concentration maximum up to 2000 ppm and over 
  • Need of hydrochloric acid system at site






hypopac pvc framed electrolyser                  

CTE Overview


  • No acid cleaning required if minimum flow is maintained
  • Allows easy replacement of cell modules
  • Self-cleaning tubular cell design is suitable for small capacity systems (<5-15kg/hr) and offshore applications
  • High capital cost (more titanium) and high maintenance cost
  • Many connections means frequent leaks which cause further corrosion if leaky modules are not replaced
  • Frequent failures–expensive spares
  • Excessive seawater impurities can cause tenacious scale deposits on electrode surfaces
  • All calcium-magnesium deposits conveyed in to the hypochlorite storage tank with a consequent leaning and removal of deposits to be effected very often that otherwise would damage injection pumps
  • High power consumption
  • Larger layout requirement
  • Hypochlorite concentration maximum up to 1300-1500 ppm


concentric tubular electrodes ppe electrolyzer



Technology Selection




System Availability

Any electrochlorination system must provide continuous/shock dosing to avoid risk of power plant shutdown. Based on recent several plant surveys at CUSTOMERS site, CTE systems are shut down at least once every 2-4 weeks to replace faulty cells or gaskets. Low availability of CTE electrolyzer necessitates 100% standby spare and on-going purchase of spare cells (good business for spare parts supplier)

CTE Availability=                97-98%

Chloropure Availability=   99.5%

CTE Downtime is 5 times greater than Chloropure


Capital Cost

  • CTE tubular cell utilizes only one side of titanium surface–more titanium material required
  • Chloropure “intermeshed electrodes” use both sides of titanium surfaces. Entire electrode pack is cased in FRP pressure vessel.
  • Capital cost of Chloropure electrolyzer is 30-40% less than CTE of same capacity


Power Consumption

CTE unconventional tubular geometry provides the benefit of self cleaning due to high flow velocities but poor power consumption (more than 5 AC kwh/kg chlorine)

Choropure electrode geometry Is proven industry standard intermeshed Electrode design for efficient gas/liquid separation. Powerconsumptionis only4 AC kwh/kgchlorine

Annual power cost for typical 500 kg/hr system using rate of $0.08/kwh(typicalrate for grid power):

CTE System        $1,750,000

Chloropure         $1,400,000

Annual Power Savings with Choropure=$350,000


Susceptibility to Leaks

  • CTE cells operate at high pressure (6-7bar) to induce the high flow velocities of 4 m/s through the annular cells. In essence, the electrolyzer is a long annular pressure vessel thin wall titanium tube for the inner and outer electrodes.
  • In addition, for example a 50 kg/hr CTE electrolyzer contains 300 gasketed joints with threaded PVC unions – each joint is a potential leakpoint.
  • In the field, a small leak at the unions will drip on to the other titanium electrode surfaces to cause electrolytic corrosion and catastrophic leaksas shown on the example below:


Maintenance Cost

  • SESPI Chloropure electrolyzer is comprised of an intermeshed electrode assembly that is fully enclosed within an FRP housing, as shown


  • Leaks are very uncommon and never noticed
  • CTE cells must be replaced every 3-5 years due to wear of anode coating. Chloropure cells are proven to last 6-8 years in normal operation with routine acid cleaning
  • On average, one faulty CTE cell is replaced every month per electrolyzer due to mechanical problems with leaks, gaskets, and corrosion. In comparison, a Chloropure electrolyzer may need to be repaired 1 or 2 times between the 6-8 year cell replacement cycles.
  • Average annual maintenance cost for 500 kg/hr system (electrolyzer components only - excluding cost of labour):

CTE -                          $ 650,000 (12x10 spare cells + complete replacement for coating)

Chloropure   -          $ 100,000 (Inspection, gaskets, spare anodes & cathodes)

Annual Maintenance Savings with Chloropure®- $550,000



Layout Requirements

  • SESPI Chloropure® electrolyzer requires 60-75% less floor space than a CTE of the same capacity
  • A smaller footprint results in lower installation costs related to foundations, buildings and utilities


Effect of Seawater Impurities

  • Seawater typically contains manganese, calcium, organics and other impurities that can deposit on the surface of the electrodes
  • Routine acid washing of a Chloropure® electrolyzer ensures that the long term negative effects of such calcareous deposits is minimized and power consumption remains low.
  • CTE is designed to handle some level of seawater impurities but for excessive levels of contaminants or during upsets, electrodes can suffer permanent damage and higher power consumption since there is no acid cleaning system


Safety and Operability

  • CTE cells have power applied directly to the cell modules using bus bars and cabling – potential electrical shock hazard during operation
  • CTE - Unbalanced cell circuit causes stray currents
  • CTE – Potential for eye irritation due to leaks spraying onto
  • operating personnel
  • Chloropure® cells are completely enclosed in non-metallic casing with bus connections at the end. Bus connections are also enclosed for personnel protection
  • Chloropure® cells can be supplied with clear “transparent view window” for visual indication of electrodes during operation




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