Factors Leading to Apparent Opacity for Bleach Plant Scrubber Plumes, 2000 Environmental Conference Proceedings

- R. J. Young, D. G. Parrish -- Steam plumes from wet scrubbers normally dissipate to zero opacity unless there is a high level of particulate present. Bleach plant scrubbers are designed to control primarily gaseous emissions. Particulate, except perhaps from entrained fiber, is expected to be absent from the bleach plant gases and the scrubber discharge. Scrubber discharge plumes should have no trailing after the water vapor has dissipated to below the saturation level by mixing with ambient air. At a Southeastern United States hardwood bleach plant, with 100 percent ClO2 substitution, persistent apparent opacity was observed. The plume had significant trailoff. After careful investigation of various physical and chemical conditions that might lead to the apparent opacity, it was determined that the effect was generated by the presence of inorganic salts and low levels of acidic aerosols. These materials caused moisture condensation below the saturation level and the formation of apparent opacity. Rerouting of gas streams containing reduced sulfur compounds and ammonia remedied the situation.