On-Line Water Chemistry Analyzers

Efficient and reliable monitoring of low concentrations of various impurities in pure water treatment is critical for microelectronics and power cycle chemistry applications. METTLER TOLEDO offers a series of sodium, silica and chloride/Sulfate Analyzers that use industry-proven technology with innovative approaches to provide assurance of water purity to minimize corrosion while maximizing water production.

What is a sodium analyzer?

A sodium analyzer is an on-line measurement system to ensure that water is not contaminated with sodium, which can be corrosive and damaging in processes that require pure or ultrapure water. They are often used in power plants for monitoring water cycle chemistry or in microelectronics manufacturing. Fully automatic, online systems such as the 2300Na Sodium Analyzer can monitor at sub-ppb sodium levels.

I measure conductivity, why should I measure sodium?

Sodium should generally be measured in addition to conductivity. Because conductivity is non-specific, it cannot distinguish between contaminants and water treatment chemicals such as ammonia or phosphates. A sodium analyzer is more specific and more sensitive. It can detect when a cation exchanger needs to be regenerated, whereas conductivity cannot "see" the sodium until the levels are too high because of the high background conductivity of pure water. The sensitivity of a sodium analyzer is critical, because contaminants in steam become many orders of magnitude more concentrated when they accumulate in the first condensation droplets in turbines, where they are very corrosive.

How does a sodium analyzer work?

The analyzer uses an ion-selective electrode designed to specifically measure sodium in the water. The sample water is treated with a reagent to suppress interference from all other ions in the water, and the electrode measures the sodium concentration in the water as it flows by in a continuous stream. With fully automatic calibration, the analyzer undergoes periodic calibration to ensure the measurements are always accurate and reliable.

What is a silica analyzer?

A silica analyzer is an on-line measurement system that uses colorimetric technology to identify silica contamination in pure water. Controlling silica is critical in power plants because silica carryover in steam can deposit on turbine blades, greatly reducing efficiency and causing imbalance of turbine blades. It is also very difficult to remove and can cause cracking and failure of turbine blades. Silica contamination in water used for microelectronics production processes can cause rejection of produced goods

How does a silica analyzer work?

Silica content analysis is a batch measurement, where sample water is taken in the analyzer and a set of reagents added to react with the silica in it. The sample water turns blue at the end of the reaction, with the intensity of color depending on the concentration of silica – the more the silica, the darker the blue color. The analyzer detects this change in color and calculates the silica level in the water. With fully automatic calibration, the analyzer undergoes periodic calibration to ensure the measurements are always accurate and reliable.

What is a chloride and sulfate analyzer?

A chloride and sulfate analyzer is an on-line measurement system that uses microfluidic capillary electrophoresis as a method for detecting chloride and sulfate ions at very low ppb limits. It is designed to support power production facilities in achieving their cycle chemistry guidelines and meeting their turbine warranty requirements. It achieves trace-level measurements not possible with typical ion-selective chloride analyzers or with cation conductivity which is a cumulative measurement of all contaminants in the sample.

Why should I use a sulfate and chloride analyzer?

Chloride and sulfate ions are highly corrosive and can cause pitting, stress cracking and other types of corrosion on boiler and steam generator tubes and turbines. The increased cycling conditions of power plants associated with the need to compensate for the unpredictability of alternative energy sources, makes them more susceptible to air intrusion which can aggravate corrosive conditions. Because frequent cycling leads to more corrosive conditions, steps need to be taken to enhance chemistry control with meaningful analytical measurements. Ion detection analyzers such as the 3000CS Analyzer offer significantly more relevant ion specific results than cation and degassed cation conductivity measurements to allow rapid monitoring and control of cycle chemistry.

How does a chloride and sulfate analyzer work?

A batch of the sample water is injected into a microfluidic capillary cartridge along with a set of reagents. On application of electricity, the chloride and sulfate ions in the sample start moving towards the anode in the cartridge and are separated as they travel through the capillaries. The separated ions pass through a conductivity cell in the capillary and the corresponding concentration of the ions is calculated from the conductivity measurement.