Cleaning of Water-Soluble Scales in Black Liquor Evaporators - A Modeling Approach

被引:4
作者
Karlsson, Erik [1 ]
Vamling, Lennart [1 ]
Olausson, Lars [2 ]
Gourdon, Mathias [1 ]
机构
[1] Chalmers, SE-41296 Gothenburg, Sweden
[2] Valmet Power AB, SE-40275 Gothenburg, Sweden
关键词
FALLING-FILM EVAPORATORS; AQUEOUS-SOLUTIONS; NA2CO3; NA2SO4; CRYSTALLIZATION; NUCLEATION; PLANT;
D O I
10.1021/ie5037353
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
In the pulp and paper industry, the evaporation of black liquor is an important step to recover heat and chemicals. Due to a substantial amount of sodium carbonate and sodium sulfate in the black liquor, evaporators typically have to address the scaling of these water-soluble salts at concentrations above approximately 50% dry solids content. To maintain their operation, the evaporators are cleaned regularly using condensate or weak black liquor. In this paper, a model for evaporator cleaning was developed based on a dissolution model established via experimental measurements. Two new correlations for black liquor were also developed from experimental measurements: the solubility limit of sodium scales in black liquor and the density of black liquor containing additional dissolved salts. The simulations indicate high dissolution rates, meaning that the limiting step for the cleaning is the feed of free water with the wash liquid. The simulation results were insensitive to the distribution of scales, the mass transfer coefficient, and the temperature. However, the results were sensitive to the solubility limit and natural salt content for wash liquors above 30% dry solids content.
引用
收藏
页码:19600 / 19611
页数:12
相关论文
共 30 条
  • [1] Density, apparent and partial molar volumes, and viscosity of aqueous Na2CO3 solutions at high temperatures and high pressures
    Abdulagatov, Ilmutdin M.
    Azizov, Nazim D.
    Zeinalova, Adelya B.
    [J]. ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS, 2007, 221 (08): : 963 - 1000
  • [2] Adams T.N., 1997, Kraft Recovery Boilers
  • [3] [Anonymous], 2003, KAM EC PULP MILL KAM
  • [4] [Anonymous], 2009, Fundamentals of Momentum, Heat, and Mass Transfer, Revised
  • [5] Solubility and solid-phase composition in Na2CO3-Na2SO4 solutions at boiling temperature:: A modeling approach
    Bialik, Marta A.
    Theliander, Hans
    Sedin, Peter
    Verrill, Christopher L.
    DeMartini, Nikolai
    [J]. INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 2008, 47 (09) : 3233 - 3238
  • [6] Brauer H., 1956, STROMUNG WARMEUBERGA
  • [7] Bremford DJ, 1999, APPITA J, V52, P30
  • [8] Frederick Jr W. J., 2004, TAPPI PAP SUMM SPRIN, P631
  • [9] Frederick WJ, 2004, TAPPI J, V3, P7
  • [10] Gourdon M, 2010, J PULP PAP SCI, V36, P98