超临二氧化碳萃取分离异丙醇-水的相平衡研究

Phase Equilibria Study for Isopropanol Extraction from Aqueous Solution by Using SupercriticalCarbon Dioxide

用静态法测定了高压下CO_2-i-C_3H_7OH二元系和CO_2-i-C_3H_7OH-H_2O三元系的相平衡数据.实验证明超临CO_2能从水溶液中萃取分离异丙醇,并打破了常压下异丙醇-水的恒沸组成.用SRK方程和Huran-Vidal混合规则,建立了CO_2-i-C_3H_7OH-H_2O三元系的热力学模型.此模型只用二元作用系数,能成功地预测三元气液平衡和平衡系线随温度压力剧烈变化的行为.最后,通过实验数据分析和模型预测,探讨了影响超临CO_2从水溶液中萃取分离异丙醇的各种条件.

The experimental phase equilibria data under high pressure for CO2-i-C3H7OH binary system and CO2-i-C3H7OH-H2O ternary system were measured by using the static method. The results indicated that isopropanol could be separated from the aqueous solution and the corresponding azeotrope could be broken by extraction with supercritical carbon dioxide. A thermodynamic model for CO2-i-C3H7OH-H2O ternary system has Leen established by the use of SRK equation and Huran-Vidal mixing rule. The ternary vapor liquid equilibria could be predicted by this model with binary parameters only. The abrupt change of the direction of equilibrium tie lines with temperature and pressure could also be described successfully. Various operation conditions for isopropanol extraction with supercritical carbon dioxide are also discussed.