Research On On-line Monitoring Technology Of Chlorine Ion From Desulfurization Slurry In Coal-fired Power Plant

Limestone-gypsum wet flue gas desulfurization is the mainstream desulfurization technology in coal-fired power plants.However,due to the lack of slurry chlorine ion concentration control in power plants,there are problems such as equipment corrosion,substandard gypsum quality,and rough desulfurization wastewater discharge.The desulfurization system of the power plant lacks a feasible chlorine ion concentration control method,and the chlorine ion monitoring is currently offline monitoring,which has the shortcomings of lack of data and untimely measurement,which further limits the desulfurization system chlorine ion concentration control,desulfurization system chlorine ion monitoring and concentration Control is of great significance to the stable operation of the desulfurization system.In order to solve the problem caused by the lack of control of chlorine ion concentration in coal-fired power plants,the online monitoring method suitable for high-concentration chlorine ions in the desulfurization slurry environment was studied,and the migration law of chlorine ions in the desulfurization system of coal-fired power plants was analyzed.Combined with the power plant The existing operation mode gives regulation suggestions.In order to realize on-line monitoring of chlorine ion concentration in desulfurization system,we first summarize the mainstream chlorine ion measurement methods,and analyze the realization path of on-line monitoring.Ion online monitoring method initially determined that the electrode method is the measurement method for online monitoring,and used the laboratory portable chlorine ion electrode method measuring instrument to study the feasibility of electrode method for the measurement of chlorine ion in desulfurization slurry.Performance test,it is found that the measuring instrument has good measurement effect.Considering the fluidity of desulfurization slurry in online monitoring,a dynamic circulation simulation test bench of desulfurization slurry is built,and the dynamic circulation simulation test bench is used to study the problems that may be encountered in online monitoring or the performance of the instrument.According to the requirements of the power plant,a chlorine ion measuring instrument was installed in the desulfurization slurry discharge pipeline of the power plant for testing.The results showed that the online monitoring of the instrument was feasible;for the pretreatment part,the effects of common pretreatment schemes were compared,and the pretreatment based on the Y-type filter was finally determined.Finally,the online monitoring device was installed in the desulfurization slurry measurement pipeline of the power plant.The online monitoring results were compared with the chlorine ion results measured by the silver nitrate titration method.The results showed that the measurement error of the instrument did not exceed 8%,which basically met the online monitoring requirements,which provides an important reference for the online monitoring of chlorine ions in desulfurization systems.Through the material balance calculation of the chlorine balance of the desulfurization system,the relationship model between the discharge amount of desulfurization wastewater and the chlorine ion concentration of desulfurization slurry is established.The real-time data of the desulfurization tower obtained by the desulfurization slurry chlorine ion online monitoring device takes corresponding actions to control the chlorine ion concentration of the absorption tower.An on-line monitoring method of chloride ion with Y-type filter as pretreatment and ion-selective electrode method as measurement unit is designed,which is used for on-line monitoring of chloride ion in desulfurization slurry of a power plant in Hubei,and the test results meet the requirements.Based on the analysis of the chloride ion distribution law of the desulfurization system,the relationship model between the chloride ion concentration of the desulfurization slurry and the desulfurization wastewater discharge is established.Operation and desulfurization wastewater discharge.