Historically, high nitrite treatment programs provided excellent corrosion control in closed loop cooling water system Monitoring and controlling these programs involved the use of off-line reagent tests and feedforward control loops. Environmental concerns led to the creation of a low nitrite treatment program which can be used in both op recirculating and closed cooling water systems. Many treatment users now require that the water treatment supplier assume responsibility for administering and controlling the chemical treatment program. These points necessitated the updating control strategies while maintaining the low corrosion rates observed at higher treatment levels. This paper discusses the problems with uncontrolled high nitrite treatment programs and the solutions of using an automated, controlled low nitrate chemical treatment program. The paper also discusses a relevant case history of a steel making system using process cooling water.
Keywords: feedback control, feedforward control, PLC (programmable chemometrics, data management software, nitrite, cooling water, logical controller), analyzer, on-line senses, chemometrics, data management software, nitrate, cooling water.