Blog Details

Power plants, the backbone of modern infrastructure, face constant challenges in maintaining equipment integrity. Among these, water chemistry – particularly pH monitoring – plays a critical role in preventing corrosion and ensuring operational efficiency.

Traditional glass pH electrodes, while effective in laboratory settings, often prove unreliable in the demanding environment of power plant water systems. Their limitations in pure water conditions, susceptibility to electromagnetic interference, and high maintenance requirements have driven the search for better solutions.

This innovative approach bypasses the shortcomings of conventional pH electrodes by employing two conductivity sensors positioned before and after a strong acid cation exchanger. The method calculates pH through precise conductivity measurements, offering significant advantages:

• Enhanced accuracy: Particularly in low-conductivity water samples where traditional electrodes struggle
• Reduced maintenance: Robust sensors require less frequent calibration and replacement
• Improved reliability: Less susceptible to electromagnetic interference common in power plants

The method's core principle lies in the cation exchanger's ability to replace water sample cations with hydrogen ions. This transformation creates measurable conductivity changes that correlate directly with pH levels.

Two primary calculation formulas have been developed:

pH = log [Cond SC – (Cond CC/ 3)/ C B] + 11

pH = log [Cond SC– (Cond CC/3)] + 8.6

Successful application requires attention to several critical factors:

• pH range limitations of the calculation formulas
• Phosphate concentration thresholds (below 0.5 mg/L)
• Restriction to ammonia or sodium hydroxide alkalizers
• Temperature compensation models tailored to water chemistry

A complete implementation requires:

• Stainless steel conductivity sensors (k=0.1 electrode constant)
• Signal transmitters for PLC integration
• Programmable logic controllers for real-time calculations

The method has demonstrated success in diverse power plant applications:

• Boiler feedwater monitoring in coal-fired plants
• Secondary circuit pH control in nuclear facilities
• Condensate system protection in thermal plants

Emerging enhancements focus on:

• AI-driven data analysis for predictive maintenance
• Integrated sensor-transmitter systems
• Wireless monitoring networks
• Miniaturized sensor technology

This innovative approach represents a significant advancement in power plant water chemistry management, offering improved reliability, reduced operational costs, and enhanced equipment protection.