Solution Ground pH Controller for Power Plant Water

Continuously and accurately measuring and controlling the pH value of the water vapor system in power plants is one of the main means to control metal corrosion in the water vapor system. The difficulty of pH monitoring in power plants lies in the high-purity water samples such as feed water, condensate water and steam. There are many special interference problems in accurately measuring the pH value, resulting in large errors in the actual measurement values of many power plants, causing corrosion of the water vapor system. The water purity of the water vapor system of thermal power generating units is very high. It is generally not allowed to add corrosion inhibitors. The pH value of the water is mainly adjusted by adding ammonia, and a small amount of deoxidizer or oxygen is added to achieve the purpose of preventing metal corrosion in the water vapor system. . In order to prevent corrosion of steel and copper in water and steam systems, it is generally required to control the pH value of water within a strict range, which requires the use of pH sensors and pH controllers. The APX2-G4 model online Ph Orp Controller developed and produced by Daruifuno is specially designed for power plant pure water with ASP500 solution ground electrode. The controller has two relays that can set high and low alarms, and automatically adjusts the pH value according to the pH value measured by the pH electrode. The medicine pump controls the pH value within a certain range.

Specification

The boiler water and boiler feed water in the power plant are ultrapure water with very low conductivity. Years of field application have proven that the factors that affect the measurement accuracy of the online pH analyzer are: electrostatic charge, liquid junction potential, temperature, glass electrode quality, electrode Response time, contamination of the electrode surface, electrode usage time, grounding conditions, external interference and other factors. Therefore, ordinary pH analyzer measurements will have measurement deviations.

How to reduce the interference of pure water on pH value measurement? There are several targeted measures:
1. The pH flow cell and connecting tubes should be made of stainless steel, preferably 316 stainless steel, or electrolytically polished 304 stainless steel, and the entire system should be well grounded to eliminate the influence of static electricity. At the same time, the entire measurement system is required to have good sealing and shielding properties to reduce electromagnetic interference and prevent air from leaking into the water, causing measurement errors.
2. For pH controllers, it is necessary to have a temperature compensation function to eliminate errors caused by temperature changes. Additionally, there is a separate solution ground connection to eliminate the effects of ground loops. Provides a variety of calibration functions for higher accuracy measurements.
3. Influence of flow rate and pressure: The flow rate of water sample flowing through the flow cell should be controlled within a certain range, because the potential output of low conductivity water pH measurement will change with the change of water sample flow rate.

The ASP500 electrode has a solution ground and can measure water quality with conductivity below 5uS/cm. If you are interested in this sensor, you can find its specifications in the pH sensor category. Delfino has been focusing on the R&D and production of water quality analysis instruments for more than ten years. Our main products include Ph Orp Analyzer, Conductivity Analyzer, Turbidity Analyzer, Cod Analyzer, Dissolved Oxygen Analyzer, ammonium analyzer, chlorine analyzer, etc. If you are interested in our products, please contact us.