Rainbow H2O

Electro Deionization Systems

Overview of Electro Deionization Systems

The Electro-Deionization process is the latest technology to achieve ultrapure water. EDI uses ion exchange resins in the presence of a DC voltage potential to remove cation and anion contaminants from the feed water supply. Ion selective membranes are then used within the modules to continuously remove these contaminants and carry them out in a small concentrate stream. The voltage applied across the cell allows for the electrochemical “splitting” of water into hydrogen (H+) and hydroxide (OH-) ions within the ion exchange resins resulting in constant regeneration without the addition of chemicals, wastewater neutralization/disposal, and shutdown time. This results in a major advantage over the operation of traditional, regenerable Mixed-Bed Deionization and Service Exchange DI Systems.

The following are just a few of the industrial applications that can benefit from purified water produced by EDI systems:

  • Power Generation
  • Industrial Process Water
  • Chemical Manufacturing
  • Boiler Feed
  • Electronics / Semiconductor
  • Research Lab Facilities

Operating Parameters

  • Nominal Recovery: 90–95%
  • Operating Temperature: 50–100° F
  • Expected Pressure Drop: 30–40 psig
  • EDI Water Quality: 15–18 meg-ohm
  • Maximum Inlet Pressure: 100 psig
  • Electrical Requirement: 460 VAC, 3-phase, 60 Hz. 120 VAC, 1-phase, 60 Hz.
  • Feedwater Requirements: See table on reverse side
  • Minimum Inlet Pressure: 60 psig

Materials Of Construction

  • Skid Frame: Epoxy-coated carbon steel
  • EDI cell tubing: Polyethylene
  • EDI Housings: FRP
  • System piping: Sch 80 PVC

Standard Features

  • Allen Bradley MicroLogix Series PLC system
  • NEMA-4 electrical enclosures
  • Product water resistivity monitor
  • Allen Bradley PanelView operator terminal
  • Electric-actuated inlet water valve
  • Flowmeters for product, reject, and electrolyte streams
  • DC Power supply/rectifier unit
  • Individual EDI cell sampling ports
  • Feedwater pH monitor

Optional Equipment Available

  • Product water divert valve
  • CPVC system piping
  • Product water pressure relief valve
  • Feed/product water transfer pump systems
  • Alternate PLC systems
  • Feedwater resistivity monitor
  • Two-pass Reverse Osmosis (RO) pretreatment
  • EDI cell clean-in-place (CIP) systems
  • System pressure transmitters
  • Feed/product water storage tanks

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