Mathematical model of precipitation of magnesium carbonate with carbon dioxide from the magnesium hydroxide slurry

Wenli Zhao*, Bing Han, Kaj Jakobsson, Marjatta Louhi-Kultanen, Ville Alopaeus

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)
108 Downloads (Pure)

Abstract

A mathematical model is proposed for a precipitation process of magnesium carbonate in a heterogeneous stirred tank reactor. The model includes a description of dissolution of Mg(OH)2, absorption of CO2 and precipitation of MgCO3. The Nernst-Planck equation is used in the dissolution model to maintain the mass balance and electroneutrality. The van Krevelen-Hoftijzer expression is introduced to describe the enhancement effect of reaction between dissolved CO2 and OH- on the mass transfer rate of dissolution and absorption. In the precipitation model, a simplified population balance equation is solved by a moment method for both dissolving and precipitating particles. Unknown precipitation kinetics parameters for Mg(OH)2MgCO3 system are fitted against experimental data and compared with Ca(OH)2CaCO3 system. According to the present analysis, the liquid-solid and gas-liquid mass transfer dominate the global rate of precipitation. The precipitation kinetics and pH have strong influences on the concentration of reactants and the yield of precipitation.

Original languageEnglish
Pages (from-to)180-189
Number of pages10
JournalComputers and Chemical Engineering
Volume87
DOIs
Publication statusPublished - 6 Apr 2016
MoE publication typeA1 Journal article-refereed

Keywords

  • Absorption
  • Dissolution
  • Heterogeneous reaction
  • Mass transfer modeling
  • Nernst-Planck
  • Precipitation

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