The solid?liquid equilibrium data of N,N′-bis-(2-hydroxypropyl)-piperazine (HPP)?sodium sulphate?water ternary system were determined by isothermal method at 273.15 and 298.15 K under ambient pressure by wet-residue method. The components of invariant points were determined by XRD and FT-IR analysis. Two isothermal phase diagrams were plotted according to the equilibrium data. There were four crystalline regions in the course of crystallization (pure Na2SO4?10H2O, pure Na2SO4, mixed Na2SO4?10H2O and Na2SO4, mixed Na2SO4 and HPP, respectively) at 298.15 K. Meanwhile, there were three crystallization regions (pure Na2SO4?10H2O, mixed Na2SO4?10H2O and HPP, mixed Na2SO4?10H2O, Na2SO4, HPP, respectively) at 273.15 K. With the decrease of temperature, the crystallization regions of pure Na2SO4?10H2O increased and the solubility of sodium sulfate decreased obviously. The presence of HPP decreased the phase transition temperature between Na2SO4 and Na2SO4?10H2O, resulting in the existence of pure Na2SO4 crystalline region at 298.15 K. But there was not crystallization zone of pure Na2SO4?10H2O at 273.15 K. Moreover, the existence of pure HPP crystalline region had not been found at 273.15 and 298.15 K, that meant if the concentration of HPP was lower than the solubility of HPP in water, HPP would not crystallize in the frozen crystallization process. Furthermore, the modified Pitzer model of single component electrolyte was used to correlate the phase equilibrium data of the system. By means of the solubility data, the Pitzer parameters and solution equilibrium constants of Na2SO4 and Na2SO4?10H2O in the system were calculated by multiple linear regression. Using the Pitzer model to calculate the theoretical data of phase equilibrium, the relative root mean square deviation between the calculated data and the experimental data was no more than 0.0290, which proved that the modified single component electrolyte Pitzer equation can be applied to the calculation of this system.
Yating LIU Peng CUI Shaojun JIA
. Determination and calculation of phase equilibrium for N,N′-bis-(2-hydroxypropyl)-piperazine-sodium sulphate?water ternary system[J]. The Chinese Journal of Process Engineering, 2020
, 20(2)
: 141
-147
.
DOI: 10.12034/j.issn.1009-606X.219183
[1] Wei F Y, He Y, Xue P.et al. Mass transfer performance for low SO2 absorption into aqueous N,N’-Bis(2-hydroxypropyl) piperazine solution in a θ-Ring packed column. Industrial & Engineering Chemistry Research. 2014, 53, 4462?4468.
[2] 崔鹏, 魏凤玉, 史成武,等. 可再生有机胺脱硫剂HPP研究与应用[C]// SO2、NOx、PM2.5、Hg污染控制技术研讨会. 2016.
Cui P, Wei F Y, Shi C W, et al. Research and application of renewable organic amine desulfurizer HPP[C]// The 20th SO2, NOx, PM2.5, Hg pollution control technology seminar. 2017:30-34.
[3] Zheng Z Z, Ding F, Chen Y Z, Chen X Y, Cui P. Novel aqueous two-phase system consisting of 1,4-Bis(2-hydroxypropyl)-piperazine, Na2SO4, and H2O: temperature-dependent equilibrium data and physical properties[J]. Journal of Chemical & Engineering Data, 2017, 62(12):4064-4072.
[4] 郑争志, 刘雅婷, 崔鹏. HPP-Na2SO3-H2O双水相体系相平衡数据测定及关联[J]. 过程工程学报, 2018,18(3):555-562.
Zheng Z Z, Liu Y T, Cui P. Measurement Data and Correlation of Liquid-Liquid Equilibria for Aqueous Two-phase Systems of HPP–Na2SO3–H2O[J]. The Chinese Journal of Process Engineering, 2018,18(3):555-562.
[5] Lu J , Zhou X , Chen L W , et al. Solid–liquid equilibria of the Na2SO4 + H2NCH2CH2SO3H + H2O system from (288.15 to 328.15) K[J]. Journal of Chemical & Engineering Data, 2014, 59(6):2115–2119.
[6] Gao X Q, Zhang F, Yu Y, et al. Solid?liquid phase equilibria of the ternary system (2-naphthaldehyde + 4?methylphthalic anhydride + ethyl acetate) at(288.15, 298.15, and 308.15) K[J]. Jounal of Chemical Engineering Data, 2018, 63 (8), 2848–2855
[7] Van d S J H G , Weerdenburg H , Van d V A J , et al. Application of the Pitzer model for the estimation of activity coefficients of electrolytes in ion selective membranes[J]. Fluid Phase Equilibria, 1999, 157(2):181-196.
[8] Khoo K H, Fernando K R, Fereday R J, et al. Pitzer model parameters for sparingly soluble salts from solubility measurements. The systems TlCl+SrCl 2 +H2O and TlCl+BaCl2 +H2O at 25°C[J]. Journal of Solution Chemistry, 1995, 24(10):1039-1048.
[9] 桑世华, 崔瑞芝, 刘乾, et al. 三元体系KCl-KBr-H2O 323 K相平衡理论计算[J]. 高校化学工程学报, 2016, 30(2).
Sang S H, Cui R Z, Liu Q, et al. Phase Equilibrium of a KCl-KBr-H2O ternary system at 323 K[J]. Journal of Chemical Engineering of Chinese Universities, 2016, 30(2).
[0] 翁延博.五元体系Na+，K+，Mg2+// Cl-，Br- -H2O 313K相平衡研究[D].天津：天津大学，2008:1-70.
Weng Y B. Study on phase equilibria of the quinary system Na+, K+, Mg2+// Cl-, Br--H2O at 313 K. Tianjin, Tianjin University, 2008.
[1] 邓天龙, 周桓, 陈侠. 水盐体系相图及应用[M]. 化学工业出版社, 2013：235-238.
Deng T L, Zhou H, Chen X. Salt-water system phase diagrams and applications[M]. Chemical Industry Press, 2013:235-238.
[12] Meng L , Xu J , Du C B , et al. Determination and correlation of solid–liquid phase equilibrium and phase diagram for multicomponent system of mixed dibasic acids. (I) Ternary system of adipic acid + glutaric acid + ethanol system[J]. Fluid Phase Equilibria, 2016, 409:256-263.
[13] Yin C , Liu M , Yang J , et al. (Solid+liquid) phase equilibrium for the ternary system (K2CO3-Na2CO3-H2O) at T=(323.15, 343.15, and 363.15) K[J]. The Journal of Chemical Thermodynamics, 2017, 108:1-6.
[14] 程浩. 无机离子对HPP-SO2吸收体系的影响与分离研究[D]. 合肥：合肥工业大学, 2016:15.
Cheng H. Effect and separation of inorganic ions on HPP-SO2 adsorption system[D].Hefei:Hefei University of Technology, 2016:15.
[15] 中华人民共和国国家标准. 制盐工业通用试验方法硫酸根的测定:GB/T13025.8—2012[S]. 北京:中国标准出版社,2012:1-8.
National standards of People's Republic of China. Salt industry - General test method - Determination of sulfate: GB/T13025.8—2012[S].Beijing: China Standards Press, 2012:1-8.
[16] Boukhalfa N , Méniai, A.H. Use of the Pitzer model for correlating thermodynamic phase behavior of salts in water–ethanol mixed solvent solutions[J]. International Journal of Hydrogen Energy, 2015: S0360319915027445.
[17] Ghalami C B, Shekofteh G M, Sayyadi N F. Thermodynamic study of ternary electrolyte KCl + 1-PrOH + water system based on Pitzer and Pitzer – Simonson – Clegg models using potentiometric measurements[J]. Journal of Molecular Liquids, 2013, 188(24):49-54.
[18] Spencer R J , M?ller, Nancy, Weare J H . The prediction of mineral solubilities in natural waters: A chemical equilibrium model for the Na-K-Ca-Mg-Cl-SO4-H2O system at temperatures below 25℃[J]. Geochimica Et Cosmochimica Acta, 1990, 54 (3) : 575 - 590.
