Online fully-automatic high precision steam dryness monitoring system

Steam dryness monitoring is significant for high-efficiency steam turbines used in power generation and boilers. Although steam dryness is a crucial process variable, Mohr titration involves expensive and complex calorimeter equipment and considerable time and effort. This paper proposes an online fully-automatic high precision steam dryness monitoring system. The automatic determination of titration endpoint using the optical method, vital steps for this system, was discussed. The design shows high repeatability and precision (about 1% at 300 mg/L). The system also has high linearity, and the R² is 0.9999. The limit of the detection is about 15 mg/L. The measuring time is about 2 min for one measurement, which is much faster than manual titration. Thirty-eight water samples collected were tested, showing an excellent anti-interference characteristic.