Determination and Chemical Modeling of Phase Equilibria for the Glycine鈥揔Cl鈥揘aCl鈥揌2O System and Its Application To Produce Crystals with Anticaking Characteristics

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• 作者：Wencheng Gao ; Zhibao Li
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：June 20, 2012
• 年：2012
• 卷：51
• 期：24
• 页码：8315-8325
• 全文大小：502K
• 年卷期：v.51,no.24(June 20, 2012)
• ISSN：1520-5045

文摘

The phase equilibria of the glycine鈥揔Cl鈥揘aCl鈥揌₂O system were determined in the concentrations up to 3.33 mol路kg^鈥? over the temperature range from 283.2 to 363.2 K using a dynamic method. A rigorous chemical model for the glycine鈥揔Cl鈥揘aCl鈥揌₂O system was established by the Pitzer model with the help of an OLI platform. With the equilibrium constants of dissociation reactions obtained by standard-state thermodynamic data, the new Pitzer model parameters were harvested by regressing solubility of the system. These newly obtained parameters were used to accurately predict the multiple saturated points at the temperature range from 283.2 to 363.2 K. The phase behavior of the ternary glycine鈥揔Cl鈥揌₂O and glycine鈥揘aCl鈥揌₂O system at 298.2 and 343.2 K were successfully visualized with lucidity on an equilateral triangle. To investigate the effect of glycine on the morphology of KCl, the KCl crystals were produced from glycine solution with different concentration (17鈥?5% w/v) by evaporation at ambient temperature. The glycine (25% w/v)-modified KCl crystal changed its morphology from native cubic to hexagonal prism form with the angle of repose from 32掳 to 23.8鈥?5.8掳, indicating a good flowability and anticaking characteristics. Finally, KCl supersaturation variation with evaporation time was simulated with aid of the chemical model established in present study to elucidate the influence of glycine concentration on the anticaking characteristics of KCl crystal. All the results generated from this study will provide the fundamentals for industrial application to produce crystals with anticaking characteristics.