Power: pH and CO2 Determinations Based on Power Plant Conductivity Measurements

Described here are capabilities to read out pH in real time based on calculations from specific and cation conductivity values. On cycle chemistry samples, calculated pH can be more accurate and more reliable than high purity pH measured with a conventional glass electrode. It is recognized that this inferred measurement has major limitations well outside normal operating conditions, where the electrode will give a much more accurate reading. Availability of both types of pH measurement in multi-parameter instrumentation provides the best of both worlds: high accuracy by calculation within normal operating conditions and direct electrode pH measurement for confirmation when operation goes out of the normal range. Because specific and cation conductivity measurements are already required for most samples, the calculated pH value can be obtained at no additional cost. This work describes some of the improvements in instrument reliability, ease of use and capabilities that raise confidence in these on-line measurements.