Organics can foul resins, cause corrosion, and curb heat exchange surface efficiency. Key to confirming and troubleshooting the removal of organics is reliable on-line total organic carbon measurement.
How organics harm your plant
Organic contamination of cogen power plant pure waters can cause a number of costly problems. These include fouling of resins in make-up and condensate polishers; breakdown of organics to acids that can cause boiler and turbine corrosion; and deposition onto heat exchange surfaces leading to significantly reduced efficiency. Any of these problems can be a major concern in a plant.
Where organics come from
In the power / steam cogeneration cycle, it is the purified condensate returning from production processes that is most likely to be subject to organic cross-contamination from the production process.
The second most likely source of organics is make-up water. Surface water, reclaimed water, and even municipal wastewater are increasingly used as the raw source for make-up water for the water / steam cycle. All these sources have high levels of organics.
Ion exchange resins in the treatment system are another source, as the beads themselves are composed of organic polymers that break down and are released over time.
Organics cannot be normally measured by conductivity
Condensate purity is normally monitored by conductivity measurements. However, as mentioned, organic compounds from production processes may contaminate the condensate.
These organics are generally nonconductive and therefore cannot be detected via conductivity measurement.
For detection of these organics, they must be converted to a form that produces conductive species in pure water. In TOC analyzers using the wellestablished UV oxidation method, organics are oxidized and produce carbonic acid – a conductive species. The conductivity of the carbonic acid generated is then measured and correlated to the amount of organic contamination present in the water.
METTLER TOLEDO Thornton’s 450TOC and on-line 4000TOCe analyzers both use the UV oxidation technique to provide continuous and reliable monitoring of TOC levels in water or condensate.
The portable 450TOC allows the user to easily and rapidly profile the water system at multiple measurement locations, or can be used in the lab with grab samples.
For critical sample points requiring continuous monitoring, the 4000TOCe is an ideal solution offering the technology advantages of the 450TOC in an on-line instrument. With continuous measurement and rapid response time, the 4000TOCe provides peace of mind that TOC contamination is not damaging expensive plant assets.
Continuous TOC measurement safeguards condensate purity
Provides first results 80 % faster than traditional methods
Quickly capture and analyze results with on-board USB data collection
Rugged design and ease of access to internal assemblies leads to low and easy maintenance
Easy and economical integration into water purification, make-up, and sample monitoring systems
Simple interface with single-channel M300 transmitter for real-time measurements
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