pH measurements in the bleach towers have historically been among the most difficult applications in the pulp mill.
The high pulp consistency of the process stream and harsh bleaching chemicals degrade the performance of most general purpose sensors. Those sensors tend to require regular cleaning and may not be able to withstand the strongly oxidizing environment. Deposits can be a major problem in all steam boilers. In pulp and paper mill steam boilers, any accumulation of material on internal surfaces may result in overheating and/or corrosion which can result in a shutdown.