1、 Working principle
The desulfurization pH electrode is based on the principle of electrochemical primary cell, and the pH value is determined by measuring the electrode potential difference corresponding to the concentration of hydrogen ions (H ⁺) in the solution. Its core structure consists of measuring electrodes (glass electrodes) and reference electrodes:
Measurement electrode: Glass film has selective response to H ⁺. When the electrode is immersed in a solution, the concentration difference of H ⁺ inside and outside the film produces a potential difference (membrane potential), which is linearly related to the pH value of the solution.
Reference electrode: provides a stable potential (such as Ag/AgCl electrode), which is not affected by the pH of the solution, and together with the measured electrode potential, forms the electromotive force (EMF) of the primary battery.
Signal conversion: The potential difference is converted to pH value through the Nernst equation (E=E ₀+(RT/nF) · ln [H ⁺]), and then amplified by an amplifier circuit to output a digital or analog signal.
2、 Structural characteristics
Corrosion resistant material: The electrode casing is made of PPS or PC engineering plastic, which is high temperature resistant (0-95 ℃) and pressure resistant (0-0.6MPa), suitable for the highly corrosive environment of desulfurization slurry.
Gel electrolyte and double salt bridge design: polymer gel electrolyte is used to reduce the intrusion of sulfur ions; The double ceramic salt bridge reduces the liquid contact potential, prevents slurry blockage, and ensures measurement stability.
Flat head structure and anti sticking design: The flat head electrode surface is not easily adhered to slurry, reducing cleaning frequency and extending service life.
Temperature compensation function: Integrated PT100 or NTC temperature sensor, automatically corrects the influence of temperature on pH measurement, with an accuracy of ± 0.1 ℃.
3、 Industrial applications
Flue gas desulfurization (FGD) system: Real time monitoring of the pH value of the absorption tower slurry (usually controlled between 5.5-6.0), optimization of limestone slurry supply, balancing SO ₂ absorption efficiency and equipment scaling risk.
Limestone gypsum wet desulfurization: Through pH feedback control, it prevents SO ₂ from escaping due to low slurry pH or limestone dissolution inhibition and equipment corrosion caused by high pH.
Slurry pool and pipeline monitoring: Supports immersion, drainage, or direct insertion installation to meet different working conditions.
In the fields of environmental protection and chemical engineering, it is widely used for pH measurement in wastewater treatment, viscous liquids, and suspended solids containing slurries, such as papermaking, pharmaceuticals, metallurgy, and other industries.