Scaling in alkaline spent pulping liquor evaporators

Abstract

This chapter discusses the fouling that occurs in evaporators used to concentrate the black liquor in kraft pulp mills. Initially, the chemical nature of black liquors and the location of the recovery process within the framework of the kraft mill are briefly described. It includes an explanation about the different types of fouling and how they evolved over time due to changes that were made in the pulping process and due to evaporation technologies. It also describes the nature of the deposits and various proposals for mitigation. Finally, a series of case studies is presented.