低共熔溶剂应用于醇水共沸体系萃取精馏热力学模型

发布时间：2018-10-10 06:22

【摘要】：分别建立了六个四元体系的热力学模型,包括:(1)水+乙醇+甘油+氯化胆碱,(2)水+异丙醇+甘油+氯化胆碱,(3)水+正丙醇+甘油+氯化胆碱,(4)水+乙醇+乙二醇+氯化胆碱,(5)水+异丙醇+乙二醇+氯化胆碱,(6)水+正丙醇+乙二醇+氯化胆碱,关联得到二元参数。六个体系的平均绝对偏差分别是:(1)δT/K=0.40,δy=0.0044;(2)δT/K=0.15,δy=0.0035;(3)δT/K=0.16,δy=0.0043;(4)δT/K=0.15,δy1=0.0014,δy2=0.0025;(5)δT/K=0.25,δy1=0.0032,δy2=0.0031;(6)δT/K=0.25,δy1=0.0047,δy2=0.0051。建立的NRTL模型和关联得到的二元参数为潜在的应用提供设计依据。破除水+醇共沸用量由少到多分别是氯化胆碱、甘油+氯化胆碱、甘油,平衡温度由高到低分别是氯化胆碱、甘油、甘油+氯化胆碱;随着乙二醇+氯化胆碱中氯化胆碱比例提高,破除水+醇共沸用量用量减少,平衡温度降低。甘油+氯化胆碱和乙二醇+氯化胆碱对醇脱水都有很好的效果,是潜在的高效溶剂。采用统一的二元参数,研究建立统一的热力学模型,具有一定的数据推算能力。依次关联了:(1)水+乙醇+甘油三元体系;(2)水+异丙醇+甘油三元体系;(3)水+正丙醇+甘油三元体系;(4)水+乙醇+甘油+氯化胆碱四元体系;(5)水+异丙醇+甘油+氯化胆碱四元体系;(6)水+正丙醇+甘油+氯化胆碱四元体系;(7)水+乙醇+乙二醇三元体系;(8)水+异丙醇+乙二醇三元体系;(9)水+正丙醇+乙二醇三元体系;(10)水+异丙醇+乙二醇+氯化胆碱四元体系。由于氯化胆碱活度系数缺失,甘油的活度系数精度较差,采用统一的二元参数时关联精度受到限制。模型具有一定推算(预测)能力,推算了(11)水+乙醇+乙二醇+氯化胆碱四元体系和(12)水+正丙醇+乙二醇+氯化胆碱四元体系;结果与实验值吻合较好:(11)δT/K=0.52,δy1=0.0085,δy2=0.0096和(12)δT/K=0.31,δy1=0.0051,δy2=0.0057。萃取精馏脱水过程中,溶剂含水对产品纯度有重要影响。溶剂是否易于再生是萃取精馏成功应用的关键问题。本文测定了低压(5.0、5.5和6.2 kPa)下水+乙二醇+氯化胆碱体系的等压汽液平衡实验数据,建立了NRTL模型并关联了实验数据,获得了二元相互作用参数(水—乙二醇、水—氯化胆碱和乙二醇—氯化胆碱),平均绝对误差为δT/K=0.61,δy=0.0038。低压条件下,泡点温度较低,水的活度系数一般较低,与常压泡点下有明显区别;随着氯化胆碱添加量的增大,水的活度系数逐步降低,提高了萃取精馏塔中相对挥发度,但再生塔中水的活度系数降低是不利的。使用Aspen对萃取精馏和溶剂脱水过程进行模拟和优化,乙二醇+氯化胆碱不同比例为溶剂,乙醇、异丙醇和正丙醇+水为原料。萃取精馏模拟使醇达到电子级99.9%wt,综合溶剂脱水模拟,比较了乙二醇+氯化胆碱不同比例在两过程中再沸器能耗之和:乙醇脱水最节省能量的溶剂是乙二醇+氯化胆碱比例2:1;异丙醇和正丙醇脱水最节省能量的溶剂是乙二醇+氯化胆碱比例4:3。
[Abstract]:The thermodynamic models of six quaternary systems were established. These include: (1) water ethanolglycerol choline chloride, (2) water isopropanol glycerol choline chloride, (3) water n-propanol glycerol choline chloride, (4) water ethanol glycol choline chloride, (5) water isopropyl alcohol ethylene glycol chlorination Choline chloride, (6) n-propanol glycol choline chloride, The binary parameters are obtained by correlation. The average absolute deviations of the six systems are: (1) 未 T / K = 0.40, 未 y = 0.0044; (2) 未 T / K = 0.15, 未 y = 0.0035; (3) 未 T / K = 0.16, 未 y = 0.0043; (4) 未 T / K = 0.15, 未 y 10.0014, 未 y _ 2n = 0.0025; (5) 未 T / K = 0.25, 未 y = 1 0.0032, 未 y _ 2n 31; (6) 未 T / K = 0.25, 未 y 1 0.0047, 未 y = 0.0051. The established NRTL model and the binary parameters obtained by the correlation provide the design basis for the potential applications. The azeotropic amount of water and alcohol were choline chloride, choline glycerol, glycerol respectively, and the equilibrium temperature from high to low were choline chloride and choline glycerol respectively. With the increase of the ratio of choline chloride in ethylene glycol, the amount of azeotropic water and alcohol was reduced, and the equilibrium temperature was decreased. Glycerol choline chloride and ethylene glycol choline chloride have good effect on alcohol dehydration and are potential efficient solvents. The unified thermodynamic model is studied by using the unified binary parameters, and it has certain ability to calculate the data. The relationships are as follows: (1) water ethanol glycerol system; (2) water isopropanol glycerol system; (3) water propanol glycerol system; (4) water ethanol glycerol choline chloride quaternary system; (5) water isopropanol glycerol system. Choline chloride quaternary system; (6) water n-propanol glycerol choline chloride quaternary system; (7) water ethanol glycol ternary system; (8) water isopropanol ethylene glycol ternary system; (9) water n-propanol glycol ternary system; (10) water alcohol glycol ternary system Isopropanol glycol choline chloride quaternary system. Because of the absence of choline chloride activity coefficient, the accuracy of glycerol activity coefficient is poor, and the accuracy of correlation is limited when the unified binary parameter is adopted. The model has the ability to predict (11) water ethanol-glycol choline chloride quaternary system and (12) water n-propanol ethylene glycol choline chloride quaternary system. The results are in good agreement with the experimental values: (11) 未 T / K _ (0.52), 未 y _ (1o) 0.0085, 未 y _ (2) 0.0096 and (12) 未 T _ (%) K _ (0.31), 未 y _ (1) 0.0051, 未 Y _ (2) O _ (0.0057). In the process of dehydration by extractive distillation, the purity of the product is influenced by the water content of the solvent. Whether the solvent is easy to regenerate is a key problem in the successful application of extractive distillation. In this paper, the isobaric vapor-liquid equilibrium data of low pressure (5.0? 5. 5 and 6. 2 kPa) aqueous ethylene glycol chloride system are measured. The NRTL model is established and the experimental data are correlated. The binary interaction parameters (water-ethylene glycol) are obtained. The mean absolute error of water-choline chloride and ethylene glycol-choline chloride) is 0. 61 for 未 T / K, 0. 0038 for 未 yn. Under the condition of low pressure, the temperature of bubble point is lower, the activity coefficient of water is generally lower, and the activity coefficient of water is obviously different from that under atmospheric pressure, and the activity coefficient of water decreases gradually with the increase of the amount of choline chloride, and increases the relative volatilization of water in extraction distillation column. However, the decrease of the activity coefficient of water in the regenerated tower is unfavorable. The extraction distillation and solvent dehydration process were simulated and optimized by Aspen. Different proportion of choline glycol chloride was used as solvent, ethanol, isopropanol and n-propanol water as raw materials. Extractive distillation simulation enables alcohols to reach electronic grade 99.9 wt, and synthesizes solvent dehydration simulation, This paper compares the sum of energy consumption of reboiler in different proportion of choline glycol chloride in two processes: the most energy-saving solvent for ethanol dehydration is choline glycol chloride ratio 2: 1; the solvent for dehydration of isopropanol and n-propanol is the most energy-efficient solvent. The ratio of choline glycol chloride to choline chloride is 4: 3.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ028.3

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