In the chemical water treatment system of thermal power plants, the core working unit of the mixed bed for desalination, softening and advanced treatment is the ion exchange resin. Among them, the regeneration process of the ion exchange resin determines the fate of the water and steam quality of the entire power plant. The monitoring of the concentration of the regeneration solution is an important foundation for the economy and safety of the power plant. A difference of a few percentage points in the concentration of acid and alkali seems like a trivial matter, but it may determine whether this round of regeneration saves 15% of the reagent or lays the foundation for corrosion and scaling in the water and steam system.

The regeneration of ion exchange resins is essentially a chemical stoichiometric game. Whether it is using hydrochloric acid (HCl) to restore the positive resin or using sodium hydroxide (NaOH) to activate the negative resin, the core logic is to "replace" the contaminants on the resin through a high-concentration ionic solution.

In the traditional operation mode, this process is fraught with uncertainties. Operators usually set the water inflow of the jet pump based on experience or calculated values, maintaining the acid and alkali concentrations within a certain range. However, the "set value" does not equal the "actual value". During the transportation of the regenerant solution, it is subject to multiple disturbances such as temperature fluctuations, changes in dilution water pressure, wear of the jet pump, and deviations in the purity of the raw solution, causing operators to think they are delivering 5% of the regenerant solution to the resin, but in reality, it might only be 2%, or even as high as 10%.

◎Insufficient concentration: If the regeneration degree of the ion exchange resin is insufficient, it will reduce the working exchange capacity of the resin, resulting in a significant shortening of the water production cycle, deterioration of the water quality, and an increase in the operating load of subsequent desalination equipment, accelerating its performance decline.

◎Excessive concentration: Wasting chemical reagents. Excessive ionic strength may even damage the internal structure of the resin, accelerating resin fragmentation and aging. At the same time, the excessive waste liquid imposes a huge processing burden on the neutralization system.

For a long time, there has been a lack of an instrument that can work stably in a highly corrosive environment and monitor the actual concentration at the moment of regeneration in real time. The introduction of the inductive conductivity technology has precisely addressed this challenge.

In environments with strong acids and strong bases, traditional contact electrodes (two electrodes or four electrodes) are highly prone to electrochemical corrosion in acidic conditions and tend to form deposits and get clogged in alkaline conditions. Frequent cleaning, calibration and maintenance make them inadequate for monitoring the regeneration solution. Probest has developed a non-contact, inductive conductivity sensor, which utilizes the principle of electromagnetic induction and avoids direct contact between the metal electrode and the measured liquid. It has become an ideal choice for monitoring the regeneration industrial process.

Treating the inductive concentration meter merely as a device for displaying data is the greatest underestimation of its value. What truly brings out its value is to set up the measurement points according to the logic of the regeneration process.

 

 

Before the regenerant liquid enters the ion exchange tower, installing an induction-type concentration meter is not only for recording, but also for intervention. Dynamic adjustment ensures that the regenerant liquid entering the resin layer is precisely maintained within the optimal concentration range, not only guaranteeing the consistency of the regeneration effect, but also eliminating the ineffective loss of the reagents.

At the beginning of the regeneration process, the outlet conductivity will increase rapidly because the calcium ions, magnesium ions and sodium ions that have been displaced are washed out. As the regeneration progresses, the outlet concentration will gradually return to a stable level. By adding monitoring points at the outlet of the resin bed, the breakthrough curve of the regeneration solution can be tracked in real time. This not only saves a large amount of makeup water for the positive wash but also avoids the waste of resources caused by excessive regeneration.

The long-term concentration data accumulated by the sensor-type concentration meter can also provide early warnings for the health status of the resin. If a regeneration process requires much more acid or alkali than usual to achieve the same penetration effect, or if the penetration curve shows abnormal tailing, this is often a sign of resin poisoning, caking or loss.

The essence of monitoring the concentration of the regeneration solution is not to measure parameters, but to make the regeneration process controllable. The transformation brought about by Probest's inductive conductivity/concentration meter goes far beyond the digitization of readings. It makes the concentration of the regeneration solution transparent and visible, shifting from empirical judgment to data-driven methods, thereby enhancing the safety and economy of the chemical system in power plants.

The Probest sensor-based concentration meter is suitable for various scenarios such as acid-base concentration monitoring, salinity measurement, conductivity and concentration detection in special industrial processes, marine monitoring and water quality analysis. It supports multiple installation methods including flange, insertion, submerged, flow-through, three-way, and threaded connections, helping to ensure the safety and stability of industrial manufacturing.