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Crystallization in a pilot evaporator - Comparison between black liquor and black liquor model substances

Mathias Gourdon (Institutionen för energi och miljö, Värmeteknik och maskinlära) ; L. Olausson ; Lennart Vamling (Institutionen för energi och miljö, Värmeteknik och maskinlära)
Nordic Pulp & Paper Research Journal (0283-2631). Vol. 25 (2010), 1, p. 21-30.
[Artikel, refereegranskad vetenskaplig]

Crystallization measurements during semi-batch operation of a pilot evaporator have been performed. The experimental analysis is based on changes in heat transfer coefficients and crystal masses. With this method of operation, the total crystal mass as well as the distribution of the crystal mass between the circulating solution and on surfaces can be measured continuously during the evaporation. Experiments with black liquor and different black liquor model substances, all with equal carbonate-to-sulfate ratio, crystallizing burkeite have been evaluated. The results are compared to each other and to two aqueous reference solutions crystallizing dicarbonate and sodium carbonate. The results presented include solubilities and metastable limits as well as different crystallization rates and fouling rates. Generally, the supersaturation at the metastable limit observed for the different liquors was high (14-25%). All the different liquors crystallizing burkeite were seen to have significantly lower fouling rates than the reference solutions crystallizing dicarbonate and sodium carbonate. The burkeite liquors showed no specific attraction to crystallize on the heat transfer surface as the reference solutions did.

Nyckelord: Scaling, Crystallization, Black liquor, Evaporation, Sodium carbonate, Sodium sulfate, nucleation, na2co3, growth, na2so4



Denna post skapades 2010-06-11. Senast ändrad 2015-02-11.
CPL Pubid: 122681

 

Institutioner (Chalmers)

Institutionen för energi och miljö, Värmeteknik och maskinlära (2005-2014)

Ämnesområden

Kemiteknik

Chalmers infrastruktur