4 Traditionally, scale and oxygen control chemicals have been measured and controlled in the boiler waterAnalytical detection not low enough for feedwaterSample already existedVariability of the feedwater system

5 Until Recently, Control of Boiler Chemistry was Test and AdjustGather sampleTestAdjust chemical feed“Repeat as necessary”

6 Why Feedwater instead of Boiler Water?A boiler typically has a very long holding timeBD sample has little direct correlation to the feedwater at any timeEvery boiler will have unique lag timeBased on design, feedwater quality and operating conditionsLag time is always VERY LARGE relative to dosage control

8 Automated Scale Control Utilizes a Stable Inert TrasarProvides a stable inert monitor of system performanceInert tracer chemistry survives in boiler system (FW & BW)Good for boiler systems up to 1000 psig/69 bargWorks for both on-line and grab sample monitoringProvides indication of carry-over if seen in the condensateProvides positive feedback that chemical treatment is fedPatented LED fluorometer

10 Corrosion/ORP Basics Corrosion is an electrochemical process4/1/2017Corrosion/ORP BasicsCorrosion is an electrochemical processCorrosion involves both oxidation and reduction (REDOX) reactionsORP = Measures the net voltage (mV) produced by all REDOX reactions taking placeORP is a good indicator of feedwater corrosion

13 Comparison of RT ORP to AT ORPRoom temperature ORP probes:Can become polarized (inaccurate) over timeAre less sensitiveRequire cooling of the water sampleChanges water chemistryLag time reduces responsiveness

14 Comparison of AT ORP to Conventional Measurement and Control TechniquesAddresses multiple MOC corrosion mechanisms simultaneouslyWorks with any metallurgyWorks with any scavenger/passivator chemistryAT ORP is much more sensitiveAT ORP has a fast response