Success Story: Optimized pH Measurement Improves Sulfide Control in Scrubber
Japan is the third largest paper producer in the world. The number of people employed in this industry is about 230,000. Per capita consumption of paper in 2003 was 243 kg. Japan's paper industry is mainly directed towards domestic needs.
Paper production can be critical for the environment. Controlling sulfides and other odor emissions from boiler exhaust gas is a major issue for most mills. Sulfide odors can be reduced to very low levels by wet scrubbers using caustic and chlorine or sodium hypochlorite. However, chemical storage, metering, and control equipment all add to the cost of a scrubber. The chemicals are hazardous, and the volume needed is quite high, putting further pressure on operating costs. The process needs quite delicate control.
The customer, a leading Japanese paper company on the island of Hokkaido, faced problems with the pH measurements in the sulfide removal process. The pH electrode needed frequent maintenance involving cleaning and calibration, at least once a week. Despite this regular attention, the pHelectrodes at the measuring point had a lifetime of only 6 months at most. The customer was therefore very much interested in a system that would provide him with more reliability and reduce the current high cleaning effort…..