The Application Of Conductivity Method In Monitoring Boiler Water Quality And Evaluation Of Scale Inhibitors

Basing on the Water/steam system in thermal system, the significances and excellentprospect of water quality chemical diagnosis research is described according to the features ofwater/steam quality monitoring as well as the deficiency in fault diagnosis and preventivemeasures. In this research, the mechanisms and features of faults caused by impurities inWater/steam system is roundly analyzed by using both temperature response of water qualityconductivity and Cation conductivity. Then the existing problem of on-line monitoring systemare systematic presented, Probably cause can't accurate judgement water/vapor quality.Engender thermodynamic System safety or losses of thermal energy. Simultaneously study anew evaluation method of scale inhibitors based on solution conductivity measurement inRecirculating Cooling Water System, The results were the same whether static anti-scalingmethod or conductivity measurement method was employed.The experimental resultsshowed that the conductivity method has the merits of simple experimental devices, rapid andconvenient operation.Six typical working conditions models of boiler water have been chosen to manage thechanges in electrical conductivity and pH, which are traced at different temperatures.Following conclusions can be draw by analyzing the experiment results:â‘ Different watersample can lead to great differences in electrical conductivity temperature compensatecoefficient, so the temperature compensate coefficient should be chosen according to actualcondition.â‘¡The conductivity temperature responses are coincident with Arrheniusequation. The influences from the temperature to the values of conductivity activation energy(Ea) are slim, for the value of Ea show only a slight a decreasing trend as the temperatureincreases.Four typical water samples of boiler water such as, NaCl, Na₂SO₄,Na₃PO₄ andCH₃COOH have been chosen to manage the changes in conductivity and Cation conductivity,Conductivity Temperature Coefficient and Cation conductivity Temperature Coefficient,which are traced at different temperatures. Following conclusions can be draw by analyzingthe experiment results:â‘ Cation conductivity can sensitivity reflection Organic Acid withLow Molecule, Average ratio is more than 3.7 times of the conductivity for CH₃COOH.â‘¡Temperature is one of the main factors which affect Cation conductivity, which increasesremarkably with the temperature and the effect degree of Cation conductivity of Anions is different, but difference is insignificant.â‘¢The conductivity's temperature coefficient ofsame water sample is different from that of hydrogen, the former was greater than that of thelatter.â‘£The influence of different ions contained in boiler water of each kind uponconductivity's temperature coefficient of boiler water and that of hydogen isn't large.A new evaluation method of scale inhibitors has been developed and tested. This methodis based on solution conductivity measurement. In the given water, at the constanttemperature and airtight conditions, the conductivity values of the solution were measured,the point of the precipitation located. By calculating the critical supersaturation value, we candetermine the stabilizing property of scale inhibitors and determine the optimumconcentration. The experimental results showed that the conductivity method has the merits ofsimple experimental devices, convenient operation, rapid, accurate etc. We can evaluate theefficiency of different scale inhibitors at different concentration.