Corrosion Products Sampler (CPS)

New CPS Features New flow meter & totalizer AC connection standard 90-264Vac 47-63Hz input Battery option available Battery indication meter Average 3 month runtime between charges 24-48 hr recharge time Total volume is customer resettable Flow rate can also be displayed (mL/min) IEC Connector

Corrosion Products Sampler (CPS) Collects a sample of dissolved and particulate materials Totalizes sample flow ASTM D6301-98 Corrosion studies and pseudo on-line corrosion analysis Boiler tubes, pre-heaters, condenser

CPS Flow Diagram

CPS Benefits Identify corrosion products Locate source of corrosion Collects particulates for metals analysis - Fe, Cu Use anion and cation filters for dissolved metals Locate source of corrosion Quantify rate of corrosion Measure effectiveness of treatment Locate areas of corrosion product accumulation

Major Components High pressure filter holder Totalizing meter for high accuracy/low flow rates Flow control circuit Optional bypass circuit Optional sample cooler (Above 55C) Optional battery pack

Sample Point Selection Based on: System design Subject constituents Chemical treatment System specific problems

Corrosion Corrosion affects: Equipment reliability Plant safety Efficiency and capacity

Corrosion Specifically: Material degeneration at point of attack Migration through the system Collection on turbine blades Collection on heat transfer surfaces Accumulation at various points leading to additional corrosion

Why Sample? Improve plant safety & equipment reliability Increase plant efficiency and capacity Reduce frequency between routine cleanings of plant heat exchanger equipment Reduce plant operating costs

Why Sample? Use sample data to: Make adjustments in treatment Make adjustments in lay up procedures Schedule maintenance

Why Sample? Locate the sources of corrosion products Economizer, Condenser, etc. Determine the rate of corrosion Historical base, startup deviations, treatment changes Identify the type and cause of the corrosion Type of material Track the path of corrosion products Collection, settling, material removal

Typical Sampling Points Hotwell Monitor starting concentrations. DA Outlet Monitor quality of feedwater indicating problems with feedwater system components. Economizer Inlet Quality of feedwater entering the boiler Steam Quality of steam to turbine

Proper Corrosion Products Sampling Technique Isokinetic Sampling Sample velocity entering sample port is same as sample stream Sample Flow rate Constant, continuous New lines should be “seasoned” Location As close as possible to the source Fittings/Bends Minimize Tube Diameters Select to provide 6 ft/sec velocity for water Sample Tube Compatibility Refer to ASTM Method D1192, D1066

Proper Corrosion Products Sampling Technique Grab samples are not enough! Corrosion is dynamic and does not follow a regular pattern Transport is not uniform Varies with flow rates Crud bursts

Proper Corrosion Products Sampling Technique A better alternative to grab sampling: An integrated sample A measured flow through a filter for a significant period of time Collect insoluble and soluble products .45 micron filter Ion exchange filters Measure total flow

Proper Corrosion Products Sampling Technique Analyze filtered products Acid digestion + atomic absorption X-ray fluorescence Calculate average concentrations

Corrosion Products Sampler Design Criteria Inlet Isolation Valve Sample Cooler Bypass Flow Stream Filter Isolation Valve Filter Purge Filter Holder Flow Control Circuit

Inlet Isolation Valve Designed to minimize corrosion product buildup, ball or plug type if possible. Valve packing, stem and tip selected for the application

Sample Cooler Must be capable of reducing the sample inlet temperature to below 122 F (50 C) with the correct sample line velocity Sample to be cooled using a single stage cooler having no internal weld joints on the tube side

Bypass Flow Stream Used to establish the correct sample line velocity Helps to reduce and/or eliminate the effects caused by starting and stopping of sample flows through the sample filter assembly during routine changing of the filter paper

Filter Isolation Valve Isolates the filter holder during assembly and disassembly The valve should be a ball or plug type

Filter Purge Used to purge the filter holder assembly between corrosion product collections Eliminates cross contamination between samples Removes corrosion particulate that may have been released because of mechanical vibration during filter disassembly

High Pressure Filter Holder Designed to house up to one particulate filter and five ion exchange filters The screwed type design will minimize mechanical agitation during assembly and/or disassembly. Sample taken at high pressure to ensure corrosion products are not removed by the pressure reducing valve Pressure rating of 3000 psia (206 bar) and temperature of 149 F (65 C)

Conclusion Corrosion Products Samplers can be an invaluable resource to: Locate the sources of corrosion products Determine the rate of corrosion Identify the type and cause of the corrosion Track the path of corrosion products

Conclusion Improve plant safety & equipment reliability Increase plant efficiency and capacity Reduce frequency between routine cleanings of plant heat exchanger equipment Reduce plant operating costs