pH Measurement of Chlorine Dioxide Bleaching in Paper Mills

pH is measured in the chlorine dioxide towers of paper mills to control the bleaching reaction conditions and in the extraction stages to control the addition of the caustic used for extraction. While accurate pH measurement is critical in the chlorine dioxide and extraction stages, these applications are among the most challenging in a pulp mill. The high pulp consistency of the process stream and harsh bleaching chemicals degrade the performance of most general-purpose sensors as the sensors can require frequent cleaning, and may not be able to withstand the harsh oxidizing environment. The Rosemount™ RBI pH Sensor is a great choice for the bleaching process in paper mills. Multiple isolation chambers behind the reference junction act as barriers to protect the inner reference from contact with the harsh chemicals, while the high surface area of the reference junction resists plugging and maintains the electrolyte flow needed for a stable pH signal.