After Cation Exchange:
Sampling after cation exchange is one of the most important parameters in trace sodium monitoring because it rapidly alerts the operator about resin bed exhaustion.
Sodium measurement is particularly valuable in plants cooled by saline waters, especially if there is a high risk of condenser leakage and no provision for condensate polishing. Consequently, while small leaks may be extremely difficult to locate and eliminate, their detection and escalation is most readily monitored by sodium measurement.
Swan’s sodium analyzers can detect up to 0.001 ppb or 1 ppt of trace sodium in water treatment facilities. This sensitivity allows operators to follow trend changes before any leakage requires immediate action. Additionally, this advantage can be converted over time to analyze the origin of the leakage and to plan either a production reduction, or even to stop production far enough in advance to avoid costly and unexpected emergency shut downs.
After Mixed Bed Resin:
Mixed-bed resin contains a mixture of both cation and anion exchange resins for a fine polish of the pure water. It reduces any contaminant left in the pure water. Therefore, on-line sodium analysis ensures the quality of the demineralized water delivered to the make-up plant.
Solid conditioning agents, such as sodium phosphate and sodium hydroxide, used for boiler water treatment may cause deposits in the turbine and therefore need to be considered as potentially corrosive impurities.
Sodium is also measured in power plant water and steam samples because it is a common corrosive contaminant and can be detected at very low concentrations in the presence of higher amounts of ammonia and/or amine treatment which have a relatively high background conductivity.
Steam purity can be more accurately assessed by measuring sodium concentration in both steam and condensate, thus determining the “sodium balance”. The two concentrations should be equal. A higher level of sodium in the condensate indicates a condenser leakage. A lower level of sodium in the condensate indicates deposition of sodium in the steam circuit.
Sodium measurement should be the preferred option for early warnings of excursions on condensates to minimize associated risks.