Typically, chloride and sulfate measurements are done with off-line technologies such as ion chromatography and ion-selective chloride analyzers. But these may either not have the limit of detection required for the low ppb-level measurements required in power plants; or are too prohibitive to purchase, operate and maintain in terms of initial costs, ongoing ownership costs and the need for trained personnel.
Cycle chemistry guidelines have used inferred measurement such as cation conductivity, to indicate the level of chloride and sulfate in a sample. Cation conductivity measurement is a continuous, fast-responding, low-maintenance parameter that eliminates interference from ammonia and/or amines by cation exchange, but it detects all anions in the sample including carbon dioxide.
Degassed cation conductivity has been increasingly used in place of cation conductivity to arrive at a better measurement of corrosive contaminant levels in water. However, it also is a cumulative measurement and does not allow identification of individual contaminants and their levels.
Continuous monitoring of chlorides and sulfates using MCE technology provides a reliable, proactive approach to controlling the impact of some of the most corrosive contaminants in power plant water. MCE technology is based on capillary electrophoresis, which uses an electric field to separate ions in a water sample and then measures the ions’ conductivity. Microfluidic capillary electrophoresis offers a robust on-line measurement method that is easy to use and maintain, and with a low total cost of ownership.
To see how it works watch our movie on MCE Technology:
Installation at Nearman Creek Power Station
Nearman Creek Power Station, a US coal-fired power plant, decided to try continuous, on-line chloride and sulfate measurement in their facility. A METTLER TOLEDO chloride/sulfate analyzer was installed in August 2016 on the main steam sample line in parallel to the cation conductivity measurement, to analyze contaminant levels. The evaluation was conducted to analyze the concentrations of chloride and sulfate in the sample in the presence of amines, to ensure they were within industry guidelines and not causing extensive damage to key plant components.
Check out our Case Study to see the outcome of this switch to on-line analysis!
METTLER TOLEDO Sulfate and Chloride Analyzer 3000CS
The innovative 3000CS sulfate and chloride analyzer uses microfluidic capillary electrophoresis, an ionic separation technology, to directly measure trace levels of harmful sulfate and chloride ions.
With on-line measurements every 45 minutes, the 3000CS allows you to monitor your water and steam cycle continuously.
The 3000CS sulfate and chloride analyzer helps you catch contamination early, so that corrective action can be taken to avoid unplanned shutdowns and costly repairs.
Learn more about the METTLER TOLEDO 3000CS chloride and sulfate analyzer.
Watch the video: How to Monitor Chloride and Sulfate in Power Plants to Minimize Corrosion and Turbine Damage.
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