High Performance Evaporators: A Summary of Findings, Potential Applications, and Research Needs to Reduce or Eliminate Soluble Scale Fouling in High-Solids Black Liquor Concentrators, 2004 Paper Summit, Spring Technical & International Environmental Confe

The productivity and energy efficiency of many black liquor evaporators and high-solids concentrators suffer from fouling of their heat transfer surfaces. Deposition of sodium carbonate (Na2CO3) and sodium sulfate (Na2SO4) scales is a serious problem in about one third of these units. This is referred to as soluble scaling because the salts can be removed by washing with hot water. This paper summarizes a four-year study that has significantly advanced our understanding of crystallization behavior during black liquor evaporation [1]; key findings include:

  • The existence of a previously unknown species was identified. This species, termed dicarbonate, is a double salt of approximate composition 2Na2CO3⋅Na2SO4.
  • Primary nucleation of dicarbonate crystals causes soluble-scale fouling in high-solids black liquor concentrators
  • Calcium ions control the onset of nucleation of both burkeite and dicarbonate during black liquor evaporation. Work is continuing to implement changes based on this new understanding. Higher average heat transfer coefficients resulting from reduced soluble scale fouling rates will reduce steam demand for spent liquor evaporation and avoiding massive crystallization events will extend run times and reduce steam use for boil outs. These gains can reduce fossil fuel requirements and total production costs at pulp and paper mills.

    • Author: Verrill, C.L., Frederick Jr., W.J., Rousseau, R.W.
    High Performance Evaporators: A Summary of Findings, Potenti
    High Performance Evaporators: A Summary of Findings, Potential Applications, and Research Needs to Reduce or Eliminate Soluble Scale Fouling in High-Solids Black Liquor Concentrators, 2004 Paper Summit, Spring Technical & International Environmental Confe
    35.00

    New Releases

    TAPPI PRESS Catalog eBook 2026


    Experience the Power of Publications in 2026


    Open
     

    Kraft Recovery Boilers, Third Edition  


    Sponsored by the Recovery Boiler Program R&D Subcommittee of the American Forest & Paper Association (AF&PA) and published by TAPPI Press.


    Purchase
     

    Handbook For Pulp and Paper Technologists (The SMOOK Book), Fourth Edition

    The best-selling text to introduce the entire technology of pulp and paper manufacture.

    Purchase
     

    Guidelines for Safe Assessment and Operation of Yankee Dryers  


    A project of the Yankee Dryer Safety & Reliability Committee.

    Purchase
     

    Check our newest additions.


    TAPPI Press offers some of the most in-depth resources and references for the forest products and related industries. 

    See More
       
     

    Available for Purchase – Conference Proceedings


    TAPPI maintains a record of key conference papers, presentations, and other conference publications, available for purchase in a variety of formats.

    See More