Improving the Reliability of Degassed Conductivity after Cation Exchange Measurement with EDI Technology

ABSTRACT

During the startup of a water-steam cycle, CO₂ is the primary contributor to increased conductivity after cation exchange (CACE) values. It is generally accepted that CO₂ is the least aggressive contaminant in a water-steam cycle. Therefore, it is essential to reliably demonstrate that the increased CACE is due to CO₂ and not to more harmful contaminants like chloride or organic acids. Elimination of the carbon dioxide contribution is possible via thermal degassing of the sample, and subsequent measuring of the degassed CACE (DCACE). The reproducibility of the degassing process is an essential prerequisite for reliable measurements.

A CACE measurement system utilizing an electrodeionization device (EDI) for the cation exchange was introduced to the market in 2016 and has proven to be dependable. This paper describes how this established technology has been enhanced with a reliable degassing unit, resulting in a DCACE measurement utilizing an EDI device for the cation exchange.

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