Sodium and silica analysers for the power market

The CA76NA potentiometric analyser measures the concentration of dissolved sodium ions. An increase in sodium levels in boiler feedwater indicates the presence of unwanted dissolved impurities. This can cause corrosion, leaks, serious damage and expensive repairs. The analyser monitors the water/steam circuit in power stations, condensate systems for values indicating ruptures, demineralisation systems, steam and cation systems, and mixed bed exchangers.

The measurement is potentiometric using a special electrode system comprising an Na-sensitive electrode in conjunction with an Ag/AgCl reference electrode. It measures sodium over a range of 0.1 to 2000 µg/l (ppb) with accuracy and repeatabiliry of ±2%. Outputs include up to six 4-20mA channels, along with relays for alarms and warnings. The analyser is also available with Profibus DP communications.

The Liquiline System CA80SI colorimetric analyser provides precise online analysis of silica to protect plant equipment from deposits to ensure optimum performance of turbines and ion exchangers. Deposits of insoluble silicon dioxide on internal boiler walls, heat exchangers and turbine blades have an adverse effect on the efficiency of power plants and increase the risk of unplanned downtime and repairs. For this reason, the silica content in boiler feedwater must be monitored.

The CA80SI measures silica concentration from 0.5 to 200 µg/l or 50 to 5 000 µg/l, each with ±2% full scale accuracy. This allows the analyser to determine the purity of boiler feed water and steam, and to provide early warnings of condenser leaks or exhaustion of ion exchangers. Its standard heteropoly blue analysis method allows direct comparability to lab results.

Seamless integration into process control systems is provided by Modbus, EtherNet/IP and PROFIBUS digital communication that can transmit advanced diagnostic information in addition to the measured variable.

Remote access via any device with a web browser is provided by an optional, integral web server, enabling full and secure access to the device configuration, measured values, diagnostic messages, logbooks and service data.