Measuring cationic conductivity is essential for monitoring water-steam cycles in power generation plants. This technique identifies ionic impurities that can compromise system efficiency and integrity. In this comparison, you'll understand the operation, differences, and benefits of electrodeionization (EDI) modules and conventional systems with cationic resins, following standards such as VGBe S-010 and ASTM D4519.
How the cation resin system works
The cation resin system removes cations from the fluid through a resin bed that releases hydrogen ions (H+). This forms an acid whose conductivity indicates ionic concentration. However, despite being widely used, this method requires periodic replacement or regeneration. Furthermore, it generates chemical residue and is sensitive to sudden changes in the sample.
Advantage: low initial cost and wide availability.
Disadvantage: high operating costs and need for waste management.
EDI Technology
The EDI module uses selective membranes and electric current to continuously remove cations, regenerating automatically. This eliminates the need for chemical reagents, offers high precision, and, consequently, integrates easily into existing systems with few adaptations.
Advantage: lower operating costs, environmental sustainability and greater reliability.
Disadvantage: higher initial investment.
In comparison, while resin has a lower initial cost, EDI significantly reduces operating costs. Furthermore, it virtually eliminates waste generation, maintains high accuracy even under adverse conditions, and ultimately proves to be much more sustainable.
Rules and regulations
The adoption of conductivity measurement technologies must follow international standards, such as:
- VGBe Standard S-010: defines parameters for water quality in power generation.
- ASTM D4519: establishes methods for determining cationic conductivity.
- EN 61326-1 and EN 61010-1: regulates safety and electromagnetic compatibility requirements.
Therefore, following these standards guarantees not only safety, but also reliability in the results obtained.
Operational and economic gains
With EDI, efficiency increases due to the absence of manual regeneration and the rapid response time (<240 seconds). Furthermore, sustainability improves considerably, as there is no need for chemical reagents. Consequently, resin purchase and disposal costs are eliminated, resulting in up to 30% savings in total cost of ownership (TCO).
Difference in conductivities and pH calculation
The distinction between specific and cationic conductivity allows for indirect pH calculations, avoiding interference and failures under extreme temperature and pressure conditions. This approach is especially useful when direct measurement is not feasible, ensuring greater reliability and reduced maintenance.
Case Studies
- Thermoelectric plant: 40% reduction in operating costs and 25% increase in data reliability.
- Petrochemical industry: total elimination of hazardous waste.
These results therefore demonstrate the potential of EDI technology for different industrial sectors.
Implementation and best practices
To adopt EDI, it's recommended to conduct a technical and economic analysis. Then, it's recommended to implement modules in pilot systems and monitor performance. Furthermore, periodic calibration and compliance with safety and EMC standards ensure consistent and long-lasting results.
Contact us and discover how to implement EDI technology in your plant, ensuring greater efficiency, cost reduction and sustainability.
Bibliography
- VGBe Standard S-010, “Water and Steam Quality for Power Plants.”
- ASTM D4519, “Standard Test Method for Determination of Cation Conductivity.”
- EN 61326-1, “Electrical Equipment for Measurement, Control, and Laboratory Use.”
- EN 61010-1, “Safety Requirements for Electrical Equipment for Measurement.”
- Dr. Thiedig GmbH & Co. KG, “CatControl EDI Technical Datasheet.”
- International Association for the Properties of Water and Steam (IAPWS), “Technical Guidance Documents.”
