Alarm at increasing amounts of dregs and solids in white and green liquor.
The flow through sensor Cerlic CTX 20/25K is a special version with Kalrez® sealing´s that withstands white and green liquor at high temperatures. Filters of different types are used to remove dregs from the green and white liquor before reusing in the boiler. It is essential to ensure that the filtering is effective to avoid incrusts in the boiler. With the Cerlic CTX20/25K, early warning of leaks and damages of filters are obtained.
In green liquor the amount of dregs needs to be below 50 mg/l (ppm) in order to ensure good mesa properties and normal payloads in the lime cycle. For white liquor a normal value is also well below 50 m/l (ppm) to not cause problems with incrusts. In modern mills with closed loops, even lower values than stated above might be needed.
The CTX20/25K installed in a by-pass loop downstream a pump with return at the suction side. The liquor temperature is normally around 95-100°C. The sensor head temperature should be kept above 85-90°C in order to avoid incrusts in the measuring cell.