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

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2016-04-06

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Language

en

Pages

10

Series

Computers and Chemical Engineering, Volume 87, pp. 180-189

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.

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Keywords

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

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Citation

Zhao, W, Han, B, Jakobsson, K, Louhi-Kultanen, M & Alopaeus, V 2016, ' Mathematical model of precipitation of magnesium carbonate with carbon dioxide from the magnesium hydroxide slurry ', Computers and Chemical Engineering, vol. 87, pp. 180-189 . https://doi.org/10.1016/j.compchemeng.2016.01.013