Challenge

High-purity water is essential for producing steam that will not scale turbine blades with silica, minerals and other contaminants. A large power generating company in North America used a competitor’s continuous electrodeionization (CEDI) system for that purpose. Some of the challenges faced with the 2-year old system included:

• The modules leaked profusely with water containing brine which caused scaling
• The scaling led to electrical shorts and arcing which caused a fire in one of the trains
• The replacement modules required up to six months for delivery
• The replacement modules then failed continuously with one train of 28 modules lasting only ten months
• Extensive manpower was required to maintain and replace the CEDI modules on a continual basis

Plant personnel had all but given up hope for the CEDI system. They needed technical expertise and a quick, dependable, leak-free solution.

Solution

Through the ReMod Program by Siemens Water Technologies, which can be used to optimize existing CEDI and CDI systems and modules, Siemens personnel:

• Met with operating personnel from the utility
• Reviewed the current system, maintenance procedures, operating conditions and expectations
• Provided a proposal, including recommendations and detailed specifications

Results

While still in progress, the existing CEDI modules within one train are being optimized with Ionpure LX-MK modules. For the optimized train, benefits now include:

• No leaks
• No brine
• No fires
• Significantly reduced maintenance and replacement requirements
• Less power consumption

Because of budgetary constraints, the existing power supplies are currently being salvaged and the second train is being rebuilt using the best of the existing competitor supplied modules.