pH Measurement in Boiler Water

BACKGROUND

Many companies use boilers to create steam and energy. The steam created from boilers can provide energy to many different processes. The importance of steam and boiler water is what makes pH a significant part of boiler water applications.

In boiler water treatment, monitoring the pH of water is very important. By having the pH of the boiler water slightly alkaline (basic), corrosion and unwanted deposits will be monitored and prevented. Corrosion will cause problems in the boiler system if not properly monitored. One way corrosion happens is when gasses, such as dissolved oxygen and carbon dioxide, have a chemical reaction with a metal, turning the metal to its constituent form. Another form of corrosion is caustic cracking. Caustic cracking can result from too much stress on the metal and/or a leakage in boiler water.

These types of corrosions are easily prevented through a basic level of pH because of an oxide film alkaline pH creates. The oxide film surrounds the surface of the boiler tube, protecting the metal from corrosion and allowing breakage in the film to heal. Keeping track of an alkaline pH level will help deter any future problems and complications in boiler water applications.
 

pH SENSOR

Because of the extreme temperature and pressure exhibited in boilers, no simple pH sensor can withstand the extreme environment in boiler water. Therefore, pH sensors should be kept in a cool and pressure-reduced sidestream sample.

S8000CD ELECTRODE SERIES

The S8000CD series is great for pH use. For applications like boiler water where pH is particularly important, the S8000CD series will be the reliable and logical choice to keep track of pH. With a pH range of 0 – 14, the S8000CD will be able to make sure the pH of boiler water is kept slightly alkaline, preventing corrosion. It has a temperature range from 0° to 100° Celsius and capable of a pressure range from 0 to 100 psig.

To withstand the high temperature and pressure in boiler water, the S8000CD series has reference gels which are heavy duty and made for high temperature. This gel protects the reference system from thermal breakdown. Also, the S8000CD series has a replaceable electrode cartridge with a reference system enhanced with Sensorex’s ERP technology. The reference system is protected by a complex path which helps shield the system from ions such as protein, silver, and sulfides that will interact with silver or chloride. The series is also constructed with PPS which gives the electrodes excellent chemical and temperature resistance.