• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.666-671
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• 2019

Calcium carbonate involves three phases such as calcite, vaterite, and aragonite. Calcite and aragonite were more thermodynamically stable than vaterite. The synthesis of aragonite crystals by the reaction with sodium carbonate and calcium chloride solutions was investigated focusing on the effect of temperature and rpm in continuous crystallizer. In the batch crystallization test, calcite was synthesized by a relatively low temperature (under $40^{\circ}C$), but aragonite was formed at high temperature. In the continuous process with 100 rpm, no aragonite was found regardless of reaction temperature. But as increasing the stirring rate to 300 rpm and 500 rpm, the ratio of aragonite to calcite increased as increasing the temperature.

• Korean Chemical Engineering Research
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• v.44 no.3
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• pp.289-293
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• 2006

In the CMSMPR (continuous mixed suspension mixed product removal)system, the effect of temperature and RPM on the CSD (crystal size distribution) in the calcium carbonate process was investigated. In the steady state operation, the change of solution pH was small. At the low temperature and below 300 RPM, volume mean size change of calcium carbonate was stable and CSD was narrow. In the SEM view, calcite and aragonite was obtained.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.200-204
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• 1986

Particle size distribution in a Continuous Mixed Suspension Mixed Crystal Removal (CMSMPR) crystallizer has been analyzed using the Population Balance (PB) model. This method presents difficulties when the growth rate of crystal depends on the crystal size. Recent studies indicate that in many cases the growth rate is dependent on size when the crystal sizes are small. In this study, a Residence Time Distribution(RTD) model was proposed to take the size dependence into account together with an appropriate numerical scheme. When compared with the approximate results based on PB model, RTD model results showed improvements also a nucleation effect which is normally unimportant for steady state analysis. Start-up data for NaCl-Water-Ethanol system was compared with computed values.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.714-719
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• 2017

The controlled synthesis of inorganic materials with a specific size and morphology is an important factor in the development of new materials in many fields, such as nanoparticles, medicine, electronics, semiconductors, pharmaceutical sand cosmetics. Solution crystallization is one of the most widely used separation processes in the chemical and pharmaceutical industries. Calcium carbonate has attracted a great deal of attention in industry because of its numerous applications. The mean crystal size, crystal size distribution and morphology are important factors in the continuous crystallization process. In this study, the continuous crystallization of calcium carbonate by the calcium chloride process was investigated. The mean crystal size and crystal size distribution data were obtained by a particle size analyzer. The morphological imaging of the crystalswasper formed by SEM. Under steady state operation, the mean crystal size change was small, but increasing the input concentration and mixing rate increased the crystal size. In this operation, some aragonite was found, but the main crystal phase was calcite.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.712-716
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• 2010

Salting-out technique was adopted to crystallize dye crystals from dye solution. Solubility of dye solution and crystallization kinetics of Reactive Red 218 was investigated. Solubility of dye solution is decreased by higher KCl concentration. The empirical expressions of salting-out crystallization kinetics for Reactive Red 218 in continuous MSMPR crystallizer was $G=6.864{\times}10^{-5}{\Delta}C^{1.207}$ and $B^0=4.8{\times}10^{22}{\Delta}C[1.1{\times}10^{-13}+{({\Delta}C)}^{0.7}{M_T}^2]$.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.198-203
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• 2012

Salting-out technique was adopted to crystallize dye crystals from dye solution. In this research solubility of dye solution and crystallization kinetics of Reactive dye (RB-8, RB-49, RR-218) was investigated. The empirical expressions of salting-out crystallization kinetics for Reactive dye (RB-8, RB-49, RR-218) in continuous MSMPR crystallizer was RB-8 in crystal growth kinetics $G=7.1{\times}10^{-4}{\Delta}C^{0.67}$ and nucleation kinetics $B^0=3.1{\times}10^{15}{\Delta}C[1.2{\times}10^{-8}+{\Delta}C^{0.7}M_T{^2}]$, RB-49 in crystal growth kinetics $G=5.2{\times}10^{-4}{\Delta}C^{0.3441}$ and nucleation kinetics $B^0=7.2{\times}10^{15}{\Delta}C[3.3{\times}10^{-8}+({\Delta}C)^{0.7}M_T{^2}]$, RR-218 in crystal growth kinetics $G=4.4{\times}10^{-4}{\Delta}C^{0.2361}$ and nucleation kinetics $B^0=6.3{\times}10^{15}{\Delta}C[7.9{\times}10^{-8}+({\Delta}C)^{0.7}M_T{^2}]$. Also, comparison of calculated crystal size distribution applying to characteristic curve method with experimental crystal size showed good agreement.

• Clean Technology
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• v.20 no.4
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• pp.383-389
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• 2014

$CO_2$ absorption processes have a good potential for large scale capture of $CO_2$ but a large amount of absorbing solution has to be regenerated, undesirably increasing the consumption of energy such as sensible heat and latent heat of vaporization. In this study, a cooling crystallization process which would separate the $CO_2$-rich potassium bicarbonate crystals from $CO_2$-lean water was developed to reduce the energy penalty. Sterically hindered alkanolamine additives were used to enhance the $CO_2$ removal efficiency and their antisolvent effect on the crystallization was found in a continuous cooling crystallizer. The production yields of crystals were increased in the sequence of 2-amino-2-methyl-1-propanol (AMP) < 2-amino-2-methyl-1,3-propanediol (AMPD) < 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), which are related to the number of hydroxyl groups in the additive molecules. Using $^{13}carbon$ nuclear magnetic resonance, the additives favored the formation of bicarbonate ions by steric hindrance effect and increased the supersaturation of $KHCO_3$. It is shown that the additives increase the mean size of crystals and crystal growth rate by increasing supersaturation. The additives are promising for enhancing the $CO_2$ removal efficiency and reducing the regeneration energy cost of $CO_2$ absorbing solution by promoting $KHCO_3$ crystallization.