| The detection of sodium ions in the steam of power plants is crucial for the economic security of the plants.Excessive concentration of sodium ions in the steam cycle system can decrease the output of the turbine and corrode the thermal equipment.Moreover,an elevated level of sodium ions in the water of the water treatment system can lead to the failure of the mixed bed in the cation exchanger and deterioration of the feedwater quality.To rigorously control the concentration of sodium ions in the steam and the effluent quality of the cation exchanger,it is necessary to calibrate the sodium meter regularly using a sodium ion calibrator to meet the requirements of precision and stability.Therefore,the sodium ion calibrator holds significant importance in maintaining the accuracy of the sodium meter,as well as promoting energy efficiency and economic security in power plants.This article primarily focuses on the development of an online sodium ion calibrator designed for calibrating sodium ion detection instruments.The main contributions of this article are as follows:(1)An analysis of the sodium ion detection method employed by the calibrator.In order to enhance the measurement accuracy of the calibrator,this article proposes a calibration method using a simulated electrode to calibrate the secondary meter,based on the research of the flow injection-ion selective electrode measurement method.The article discards the two-point calibration method and adopts the standard addition method as the calibration method for the online sodium ion calibrator.Comparison of the measurement accuracy between the two calibration methods demonstrates that the method proposed in this article is significantly superior.Additionally,the article analyzes factors that affect sodium ion measurement and provides corresponding solutions.(2)The design of the flow path and hardware circuitry of the online sodium ion calibrator.In terms of the flow path,this calibrator first selects a peristaltic pump as the liquid driving device for precise control of the injection volume,comparing it with the traditional gravity-driven method to further illustrate the rationality of the flow path design.Furthermore,a calibration device for injection volume is designed to prevent the decrease in accuracy caused by the deformation of the pipeline during prolonged operation of the peristaltic pump.An alkalization device is also designed to maintain the p H of the solution being measured.Lastly,a temperature control device is implemented to mitigate the effects of environmental temperature fluctuations on measurements.As for the hardware circuitry,the circuit design of the online sodium ion calibrator is realized.(3)The software design of the online sodium ion calibrator.The calibrator adopts Lab VIEW software on the PC side as the upper computer control software,and its advantages are introduced.Additionally,a p H correction module is designed to control the alkalization device for alkalization purposes.Calibration module for injection volume is designed to cooperate with the calibration device for injection volume,achieving correction of the injection volume.An analog resistance box is designed to work with a precision resistance box circuit to achieve resistance output.Furthermore,a PID temperature control system is designed to work with the temperature control device,ensuring temperature control stability.(4)Performance experiments are conducted on the sodium ion calibrator,including instrument response performance,instrument reproducibility,measurement accuracy comparison,millivolt generator output accuracy,and precision resistance box output accuracy experiments.The experiments are conducted in accordance with the instrument design requirements and industry standards,validating the various performance indicators of the online sodium ion calibrator. |
PDF Full Text Request