Factors Affecting Chloride and Potassium Removal Efficiency of a Recovery Boiler Precipitator Ash Treatment System

This article was first published by the Pulp and Paper Technical Association of Canada (PAPTAC).A laboratory study was performed to examine the main factors affecting the removal efficiency of chloride (Cl) and potassium (K) of ash treatment systems operated at a temperature between 60 and 100°C. The results show that the removal efficiency is directly proportional to the amounts of Cl and K in the liquid that have been separated from the ash-water slurry. For a given system, the Cl and K removal efficiency is determined by the concentration of Cl and K in the liquid and by the degree of solid-liquid Separation (DS). DS, in turn, is greatly affected by the ash concentration in the slurry and the CO3 content of the ash.This work was part of the research program on “Increasing Energy and Chemical Recovery Efficiency in the Kraft Process”, jointly supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and a consortium of the following companies: Abitibi-Bowater, Alstom Power, Aracruz Celulose, Babcock & Wilcox, Boise Inc., Celulose Nipo-Brasileira, Clyde- Bergemann, Diamond Power International, Domtar, DMI Peace River Pulp, Georgia Pacific, International Paper, Irving Pulp & Paper, Metso Power, MeadWestvaco, Stora Enso Research, Tembec, and Votorantim Celulose e Papel