Abstract
Implementation of automatic water chemistry control at power units of thermal power stations (TPS) is hindered by the unavailability of analyzers required for monitoring certain standardized characteristics of the coolant. Important characteristics include salt content and ammonia concentration in the feedwater and salt content and phosphate concentration in the boiler water. If automatic analyzers are not available, phosphate concentration in the boiler water of drum boilers with an operating pressure above 10 MPa can be determined using conductivity measurements. In this case, the concentration of phosphates is calculated using the regression equation correlating phosphate concentration with electric conductivity of a cooled boiler water sample from the salt compartment or the equation derived by transformation of the system of equations describing the ionic equilibrium in the feedwater and the boiler water. The procedure was developed based on the results of a full-scale experiment performed at the TETs-26 cogeneration power station of PAO Mosenergo. It has been demonstrated that the correlation coefficient is 1.0 and the phosphate concentration is a function of the specific electric conductivity of a direct sample and an H-cation-treated cooled sample of water taken in the salt compartment of a drum boiler. However, for practice, the results of measurement of the specific electrical conductivity of an H-cation-treated sample are the only correct ones that enables the effect of a change in the quality of the working solution of sodium phosphate or feed water to be eliminated. Additional measurements of boiler water pH make it possible to calculate the concentration of salt components and improve the reliability of chemical control if fast upsets of the water chemistry occur. The developed calculation method for determining phosphate concentrations in boiler water using conductivity measurements was verified in a TP-87 boiler with a drum pressure of 13.8 MPa at the Ivanovo TETs-3.
Similar content being viewed by others
REFERENCES
E. H. Hull and R. D. Bartholomew, “Rigorous calculation of sodium-to-phosphate mole ratios for phosphate treatment programs,” PowerPlant Chem. 8, 526–536 (2006).
T. I. Petrova, V. I. Kashinskii, A. E. Verkhovskii, P. A. Nikolaev, D. A. Repin, E. V. Chernyshov, and S. L. Bogdanov, “Investigation of the effect the concentration of phosphates in boiler water has on electrical conductivity and pH,” Therm. Eng. 54, 515–518 (2007).
SO 153-34.20.501-2003 (RD 34.20.501-95). Rules of Technical Operation of Power Stations and Grids of the Russian Federation (SPO ORGRES, Moscow, 2003).
STO 70238424.27.100.013-2009. Water Treatment Units and Water Chemistry of TPP. Conditions for Creatiion. Standards and Requirements (InVEL, Moscow, 2009).
VGB-R 450 Le. Guidelines for Feed Water, Boiler Water and Steam Quality for Power Plants / Industrial Plants, 2nd ed. (VGB PowerTech, 2004); VGB-S-010-T-00. Guidelines for Feed Water, Boiler Water and Steam Quality for Power Plants / Industrial Plants, 3rd ed. (VGB PowerTech, 2011).
B. M. Larin, E. N. Bushuev, Yu. Yu. Tikhomirova, and S. V. Kiet, “Determination of phosphate concentration in boiler water using conductivity measurements,” Therm. Eng. 55, 558–564 (2008).
B. M. Larin and E. N. Bushuev, Fundamentals of Mathematical Simulation of Chemical-Technological Processes of Heat Carrier Processing at Thermal and Nuclear Power Plants, (Mosk. Energ. Inst., Moscow, 2009) [in Russian].
B. M. Larin, A. B. Larin, and A. V. Kolegov, Measurements of Electric Conductivity and pH in Monitoring Systems of Water Chemistry at Thermal Power Plants (Ivanov. Gos. Energ. Univ., Ivanovo, 2014) [in Russian].
B. M. Larin, A. B. Larin, and E. V. Kozyulina, “A method for adjusting the dosing of phosphate solution into boiler water of drum boilers,” RF Patent No. 2518865, Byull. Izobret., No. 16 (2014).
FUNDING
The work was funded by the Russian Foundation for Basic Research, grant no. 18-08-00511).
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated by T. Krasnoshchekova
Rights and permissions
About this article
Cite this article
Larin, B.M., Larin, A.B. & Bushuev, E.N. Determination of Salt Component Concentrations in Boiler Water using Conductivity and pH Measurements. Therm. Eng. 66, 593–598 (2019). https://doi.org/10.1134/S0040601519080056
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0040601519080056