Supersaturation and crystallization kinetics of potassium chloride

Qian, Ru-Ying; Fang, Xianshen; Wang, Zhikeng

doi:10.1021/ie00090a029

Cited by 20 publications

(33 citation statements)

References 8 publications

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“…The first order of the growth process of KCl crystals was also found in [2,4,[8][9][10]. In work [2] the growth of KCl crystals was in the kinetic mode of process at very low supersaturation of solution.…”

Section: The Length Of the Induction Period Of The Crystallization Prmentioning

confidence: 87%

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Spontaneous crystallization of potassium chloride from aqueous and aqueous‐ethanol solutions Part 1: Kinetics and mechanism of the crystallization process

Linnikov

2004

Cryst. Res. Technol.

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Kinetics of spontaneous crystallization of potassium chloride from aqueous and aqueous-ethanol solutions were studied. During the crystallization of the salt the electrical conductance and optical transmission of the supersaturated solutions were measured automatically. For monitoring of the total surface of growing potassium chloride crystals at the crystallization the turbidimetric method was used. The growth rate and activation energy of the crystals were determined. The crystal growth rate was proportional to supersaturation. When the volume fraction of ethanol in the solution increased from 0 to 25.76%, the activation energy of the growth process did not change and was about 60 kJ⋅mol -1. Aggregation of the crystals was found. The aggregation kinetics of the crystals may be described approximately by the famous Smoluchowski equation for coagulation of colloidal particles.

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Section: The Length Of the Induction Period Of The Crystallization Prmentioning

confidence: 87%

“…Crystallization of KCl in MSMPR crystallizer in the kinetic mode of the process was studied by Ru-Ying Qian at al. [9]. It was found that the growth rate was proportional to supersaturation of solution [9].…”

Section: The Length Of the Induction Period Of The Crystallization Prmentioning

confidence: 98%

Spontaneous crystallization of potassium chloride from aqueous and aqueous‐ethanol solutions Part 1: Kinetics and mechanism of the crystallization process

Linnikov

2004

Cryst. Res. Technol.

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“…Though the objective of this work is to show the advantages of the methodology presented we also verified the neural network for suspension crystallization by the experimental data presented by Qian et al [12,13]. They measured the crystal growth rate and nucleation rate in different sizes of crystallizers.…”

Section: Crystallizationmentioning

confidence: 62%

“…If the nucleation rate is controlled by secondary nucleation, it can be expressed by the following equation: (13) The crystal growth rate is mainly affected by the supersaturation of the solution and can be expressed as (14) where K g and g are constants to be found experimentally. Together, the population balance, mass balance, nucleation rate, and growth rate give a perfect description of crystallization.…”

Section: Crystallizationmentioning

confidence: 99%

Neural Networks for Chemical Engineering Unit Operations

Sato

Sha

Palosaari³

1999

Chem. Eng. Technol.

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Application of artificial neural networks in simulation of chemical engineering unit operations are studied. On the basis of the present work it is suggested that the raw data describing the phenomenon should be processed so that the relationships of the input variables are studied and if relationships are found, such as dimensionless numbers, these relationships are set as inputs in the neural network. Further, if the phenomenon can be described by a simplified mathematical expression, the value calculated by such simplified solution is set as one of the inputs. The method is demonstrated by three examples, namely, by turbulent fluid flow in a tube, breakthrough curve of adsorption, and by suspension crystallization. In all cases the method presented in this work results in a more accurate simulation and in easier training of the neural network.

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“…The power of supersaturation dependence in growth and nucleation relations is the key parameter in this classification. Using Qian et al (1989) correlation, the growth of KCl crystals may be described by:…”

Section: Crystallization Kineticsmentioning

confidence: 99%

Dynamic modeling of continuous evaporative cooling KCl‐NaCl crystallizers

Tadayyon

Rohani

1999

Can J Chem Eng

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Previous work on the modeling of potash crystallizers has been mainly limited to the estimation of crystal size distribution (CSD) in the presence of only one solid component (KCI). In the present study, an attempt has been made to develop a model that incorporates NaCl as a second component that may co-precipitate along with KCI under certain operating conditions. Addition of water to prevent co-saturation or as a means of internal fines dissolution is also taken into consideration. External fines dissolution using a heat exchanger is incorporated in the model. In addition to the CSD, the model is able to predict crystal impurity resulting from co-saturation with NaC1. The predictive capability of the model is tested using limited dynamic experimental data obtained from a 1 m3 pilot plant continuous evaporative crystallizer and the steady-state experimental data from a two-stage evaporative Swenson DTB industrial potash crystallizer circuit. In both cases, a good agreement between the model predictions and the experimental data was noticed.Les travaux anterieurs sur la modelisation des cristallisoirs de potasse se sont principalement limites a l'estimation de la distribution de taille des cristaux (CSD) en presence d'un seul composant solide (KCI). Dans la presente etude, on propose un modele qui introduit le NaCl comme second composant pouvant co-precipiter avec le KCI dans certaines conditions de fonctionnement. On prend egalement en consideration I'addition d'eau afin d'empkcher la co-saturation ou comme moyen de dissolution des fines internes. La dissolution des fines externes a I'aide d'un echangeur de chaleur est introduite dans le modele. Outre la CSD, le modele est capable de predire I'impurete des cristaux resultant de la cosaturation avec le NaCI. La capacite predictive du modele est verifiee a I'aide de donnees empiriques experimentales limitees provenant d'un cristallisoir a evaporation continu pilote de lm3 et de donnees experimentales en regime permanent provenant d'un cristallisoir de potasse industriel DTB de Swenson. Dans les deux cas, on a note un bon accord entre les predictions du modele et les donnees experimentales.Keywords: evaporative cooling crystallization, modeling, KCI-NaCI-H,O, CSD, crystal purity, co-precipitation.rystallization is an important separation process in C chemical industry. It is widely used in bulk production of fertilizers such as potassium chloride, ammonium sulfate and other chemicals like sucrose and sodium chloride. The process is also employed in the production of fine chemicals and pharmaceuticals. The crystal quality is assessed in terms of the crystal size distribution (CSD), crystal purity, and shape. Customers are usually interested in large crystals with a narrow size distribution. A wide CSD with a small mean size promotes caking of crystals and dust formation during storage and product handling. Crystals with a wide CSD may need additional processes such as compaction, dissolution and recrystallization; hence, increasing the cost of the final product.Crys...

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Supersaturation and crystallization kinetics of potassium chloride

Cited by 20 publications

References 8 publications

Spontaneous crystallization of potassium chloride from aqueous and aqueous‐ethanol solutions Part 1: Kinetics and mechanism of the crystallization process

Spontaneous crystallization of potassium chloride from aqueous and aqueous‐ethanol solutions Part 1: Kinetics and mechanism of the crystallization process

Neural Networks for Chemical Engineering Unit Operations

Dynamic modeling of continuous evaporative cooling KCl‐NaCl crystallizers

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