Solvent extraction of aromatics from middle distillates: Equilibria prediction method by group contribution

This work describes a method of calculating liquid-liquid aromatics extraction of a middle distillate. The group contribution models of the ASOG and UNIFAC type are investigated. Four vapour liquid equilibrium (VLE), two solid-liquid equilibrium (SLE), three binary and six ternary liquid-liquid equilibrium (LLE) have been measured. The parameters of the models are based mainly on the data of the systems having 10–20 carbon number. VLE, SLE, and infinite dilution activity coefficient data (17–245°C) have been used for calculating interaction parameters between hydrocarbon groups and LLE data (20–80°C) for interaction parameters of dimethylformamide-hydrocarbon groups. Middle distillate representation is based on mass spectrometric and gas chromatographic analysis and on limited data of middle distillate-DMF liquid-liquid equilibrium. It is shown that the performance of ASOG and UNIFAC models are sufficiently valid in representation of data base and in extraction calculations. Considering the predictive character and the rapidi of its application this method can be useful in the preliminary study of extraction processes.     

UNIFAC模型法计算含己内酰胺体系的相平衡(英文)

An extended liquid-liquid equilibrium (LLE) UNIFAC model is proposed to describe phase equilibria of mixtures containing caprolactam. In this model, caprolactam is introduced as a new group. New group interaction parameters are calibrated from 156 sets of liquid-liquid equilibrium data. The present model gives satisfactory correlation and prediction in liquid-liquid equilibrium, including quaternary systems containing the mixed solvent of an alcohol and an alkane. The model can be applied to predict caprolactam solubility in water and benzene accurately. Freezing point and vapor-liquid equilibrium of binary systems containing caprolactam are also predicted with the extended LLE UNIFAC model. Satisfactory prediction results are obtained.     

UNIFAC模型预测含α-蒎烯体系的汽液平衡数据

α-蒎烯具有一个特殊的双环双键结构。为更准确地预测含α-蒎烯体系的汽液平衡数据,利用UNIFAC模型原理对α-蒎烯进行基团重新划分,可得到一个大基团双环[3.1.1]-2-庚烯基与3个CH₃。通过对含α-蒎烯二元汽液平衡数据进行拟合,得到新基团双环[3.1.1]-2-庚烯基与CH₃、C=C、ACH、ACCH₃基团间的相互作用参数,扩大了UNIFAC模型的应用范围。与原始UNIFAC模型仅利用CH₃、C=C、ACH、ACCH₃基团预测出的含α-蒎烯三元体系汽液平衡数据进行比较,新基团模型预测的气相组成平均偏差以及温度平均偏差比原始基团模型的偏差要更小,说明新基团的划分更为合理。     

一异丙醇胺-二异丙醇胺-水体系汽液平衡预测和推算

主要利用UNIFAC基团贡献法预测一异丙醇胺-二异丙醇胺-水三元体系的汽液平衡数据,同时又根据UNIQUAC二元模型参数推算上述三元体系的汽液平衡。预测值和推算值分别与实验测定的一异丙醇胺-二异丙醇胺-水三元体系在338、353、368 K下的恒温汽液平衡数据进行比较,三者符合良好,为该三元体系平衡数据的获得提供了又一途径。     

Thermodynamics and separation process for quaternary acrylic systems

Vapor‐liquid equilibrium (VLE) and liquid‐liquid equilibrium (LLE) data of binary and ternary acrylic systems were systematically measured. Subsequently, VLLE phase diagrams of binary systems, tridimensional VLE phase diagrams of methyl acrylate (MA)‐methanol (Me)‐H₂O ternary system, and quaternary LLE phase diagrams of MA‐Me‐H₂O‐methyl acetate (MeOAc) system were constructed. These diagrams clearly demonstrated the effects of temperature on phase equilibrium. The experimental data was fitted by the NRTL and UNIQUAC models, and the best‐fitted parameters were used to predict interaction properties of ternary and quaternary mixture. Therefore, the phase equilibrium data were provided as reference for the design of acrylic systems rectification or extraction process. Residue curve was mapped out for MA‐Me‐H₂O system through Aspen plus software. Finally, using thermodynamics and residue curve as theoretical basis, two novel separation processes were proposed and applied to the quaternary acrylic systems. © 2015 American Institute of Chemical Engineers AIChE J, 62: 228–240, 2016     

Vapour-Liquid Equilibrium with a New Ebulliometer: Ester+Alcohol System at 0.5 MPa

A new dynamic ebulliometer is used to determine vapor-liquid equilibrium (VLE) data experimentally. In the equipment, both phases are recirculated. Its operation is a consequence of the Cotrell pump effect produced when the mixture is heated in a double-walled inverted vessel. The reliability of the apparatus is tested with the mixtures studied previously by various authors. VLE data for the binary systems of methyl acetate + methanol and the methyl acetate + ethanol at 0.5 MPa are determined. The experimental data are confirmed with the point-to-point test of van Ness, applying the Fortran program of Frendslund et al. In addition, the experimental results are compared with the UNIFAC (including different versions) and ASOG prediction models.     

丙酮-水-丙酮连氮体系汽液平衡测定与关联

采用汽液双循环平衡釜,在常压（101.3 kPa）下测定了丙酮-丙酮连氮二元组分物系以及部分丙酮-水-丙酮连氮三元组分物系的汽液平衡数据。实验数据经Herington面积积分法检验符合热力学一致性。通过化工过程模拟软件,分别采用Wilson、NRTL、UNIQUAC 活度系数模型对丙酮-丙酮连氮二元组分物系实验数据进行关联得到模型参数。并对汽液平衡的计算值与实验值进行比较,3种模型都吻合良好,其中由NRTL方程关联得到的计算结果最为适合,平均温度偏差和汽相组成偏差分别为0.0639 K和0.0048。从三元汽液相平衡数据中拟合出了丙酮-丙酮连氮、丙酮-水、水-丙酮连氮之间的NRTL方程相互作用参数。为验证数据及其二元相互作用参数的可靠性,利用关联出的丙酮-丙酮连氮模型参数计算出汽相组成与丙酮-丙酮连氮的二元数据比较,二者符合较好。实验和关联的结果为精馏分离丙酮-水-丙酮连氮汽液平衡体系提供了一定的基础数据。     

Vapor–liquid equilibria for ethyl acetate + methanol and ethyl acetate + ethanol mixtures: Experimental verification and prediction

This work aims of the determination of a series of vapor–liquid equilibrium (VLE) experimental data at low pressure (70 kPa) for binary mixtures of ethyl acetate with methanol and ethanol. The Fischer's ebulliometer was used for the measurements of VLE data. A complete series of equilibrium data was obtained such as pressure, temperature and compositions of the liquid and vapor phases (PTxy). The two VLE data sets were submitted to a thermodynamic consistence test, where the deviations were evaluated in all variables, using the UNIQUAC activity coefficient equation. The magnitude of the average deviations was within the experimental uncertainty satisfying the Gibbs–Duhen equation. The data sets were also used to test the prediction of the UNIFAC model in its original and modified editions and the results were also within experimental uncertainties. Then a series of binary systems containing alcohols (methanol and ethanol) and esters (methyl and ethyl acetate) were collected from the literature for testing systematically the capability of the UNIFAC contribution method for this type of mixtures.     

羟乙基乙二胺-乙二胺体系的汽液平衡

引　言羟乙基乙二胺 (Ｈ2 ＮＣＨ2 ＣＨ2 ＮＨＣＨ2 ＣＨ2 ＯＨ ,简称ＡＥＥＡ)是有机碱类化合物 ,分子中同时含有活泼的氨基和羟基 ,属氨基醇的一个品种 ,是香波、润滑油、树脂等重要原料 ,特别在表面活性剂合成方面的应用越来越广 .它是由过量的乙二胺(Ｈ2 ＮＣＨ2 ＣＨ2 ＮＨ2 ,简称ＥＤＡ)和环氧乙烷 (ＥＯ)合成的 ,产品混合物中必须将ＥＤＡ和ＡＥＥＡ彻底分离 .计算、设计ＡＥＥＡ精馏分离过程的有关热力学数据尤为重要 .本文将着重对ＡＥＥＡ的蒸气压及ＡＥＥＡ与ＥＤＡ的相平衡数据 ,用改进的静态平衡釜进行测定、关联 .而相应的这…     

基于G~E模型的MH方程在二元流体相平衡中的应用

提出了ＭＨ方程基于Ｇ￣Ｅ模型的混合法则，并用于流体相平衡计算。研究结果表明：基于ＵＮＩＦＡＣ模型的ＭＨ方程能较好地预测汽液平衡，而基于ＮＲＴＬ模型的ＭＨ方程能满意地关联液液平衡数据。     

多元渗透维里方程通式的表达：双水相系统的液液平衡计算

提出了基于三元系修正Ｐｉｔｚｅｒ模型的多元渗透维里方程通式，并应用于双水相系统液液平衡性质的关联和预测，用汽液平衡数据关联模型参数，预测了聚乙二醇／硫酸镁双水相系统的液液平衡；用汽液平衡数据和尽可能少的液液平衡数据关联模型参数。同时预测了焦点或不含电解质的ＰＥＧ／葡萄糖双水相系统的液液平衡和ＫＣｌ电解质在ＰＥＧ／ＤＥＸ系统中的分配系数。计算结果表明，模型有较好的预测功能。     

大豆油与甲醇酯交换反应体系的相平衡研究

生物柴油是一类清洁的可再生液体燃料,精炼植物油与甲醇酯交换是制备生物柴油的重要反应。针对目前难以准确获得酯交换反应体系的多组分相平衡组成等方面存在的问题,研究了间歇反应和连续逆流分离甘油等不同反应方式下大豆油与甲醇酯交换反应体系的多组分相平衡行为,并以三油酸甘油酯与甲醇酯交换为模型反应,采用UNIFAC和Modified UNIFAC模型进行了模拟计算。结果表明,在常压、60^oC反应条件下,在总组成偏离甲醇-甲酯二元组成的区域,UNIFAC和Modified UNIFAC模型准确计算了生物柴油酯交换反应体系的三元和四元相平衡组成。在甘油含量大于2.2%(质量)或转化率小于90%(质量)的酯交换反应中,计算值与实验值的平均偏差约为2%。酯交换反应相平衡的实验值和模型计算值表明,采用连续逆流方式分离甘油可以提高酯相中的甲醇含量,有利于传质和酯交换反应。这些结果为生物柴油工艺过程模拟、设备优化以及新技术开发提供了理论参考。     

二甲基硫醚-吡啶-N,N-二甲基乙酰胺体系汽液平衡关联和预测

在101.325 kPa下用沸点仪测定了二甲基硫醚-吡啶、二甲基硫醚-N,N-二甲基乙酰胺、吡啶-N,N-二甲基乙酰胺3个二元体系以及二甲基硫醚-吡啶-N,N-二甲基乙酰胺三元体系不同液相组成时的汽液平衡数据,3个二元体系活度因子分别用Wilson、NRTL、Margules、van Laar和UNIQUAC模型进行关联,用最小二乘法求出了它们的液相活度因子模型参数,用这些模型参数计算它们的汽相组成。根据过量Gibbs自由能函数,采用间接法由Tpx预测了3个二元系的汽相平衡组成。用所得的液相活度因子计算3个二元体系的过量Gibbs自由能。3个二元体系的Wilson、NRTL、Margules、van Laar和UNIQUAC模型参数分别对所测的三元体系数据进行关联,建立该系统汽液平衡的热力学模型并计算平衡时的汽相组成和泡点温度。分别由Herington法和McDermott-Ellis法对3个二元体系和三元体系进行热力学一致性检验,结果表明这些相平衡数据满足热力学一致性。     

顺丁烯二酸二甲酯+甲醇二元体系气液平衡数据实验测定及模拟

采用改进的Rose釜测定了顺丁烯二酸二甲酯+甲醇二元体系在常压下的气液平衡数据,并利用Wilson、NRTL和UNIQUAC活度系数模型对其进行了热力学计算,得到了3个模型的模型参数。用Wilson、NRTL和UNIQUAC模型关联该二元体系的气液平衡所得平衡温度计算值和实验值的均方根偏差分别为8.8811E-06,0.0005,2.1959E-06;液相组成的均方根偏差分别为0.0317,5.1243E-05,0.0307;气相组成的均方根偏差分别为0.0012,0.0080,0.0011,显示了比较好的一致性。本工作为相关研究提供了热力学基础数据。     

基于UNIFAC模型的基团-OCOO-与-CH3,ACH,CH3OH和CH3COO-的交互作用参数估算与验证

Isobaric vapor-liquid equilibria (VLE) are experimentally measured for the binary systems of dimethyl carbonate (DMC) ethylene carbonate and methanol ethylene carbonate at 101.325kPa. The thermodynamic consistency of these experimental data is tested with an available statistic method. Interaction parameters of the carbonate group —OCOO— with the group —CH3, ACH, CH3OH and CHACO0— in UNIFAC model are determined using the experimental and literature VLE data. The results show that the calculated VLE data using the new UNIFAG parameters agree excellently with the experimental data in this work and in literature. These results are useful in the research on DMG and diphenyl carbonate synthesis by transesterification in design of reactor and distillation tower.     

Isobaric vapor–liquid equilibrium for ternary system of ethanol,ethyl propionate and para-xylene at 101.3 kPa

Isobaric vapor–liquid equilibrium(VLE) data for the binary system ethyl propionate(2) + para-xylene(3) and ternary system ethanol(1) + ethyl propionate(2) + para-xylene(2) at atmospheric pressure(101.3 k Pa)were obtained by a VLE modified othmer still. All the experimental data passed a point to point consistency test of Van Ness method, which verified the data reliability. The Wilson and UNIQUAC activity coefficient models were employed to correlate the binary VLE data to obtain binary interaction parameters. Based on binary interaction parameters, ternary VLE data of ethanol(1) + ethyl propionate(2) + para-xylene(3) were predicted by Wilson and UNIQUAC models, which proved that predicted values are consistent with the experimental data.Furthermore, azeotropic phenomenon between ethanol and ethyl propionate disappears when the mole ratio of para-xylene and binary system of ethanol and ethyl propionate is 1:1. Therefore, this paper convinced that para-xylene is a proper extractive additive that could be used in extractive distillation to separate the binary azeotropic system of ethanol and ethyl propionate.     

LIQUID-LIQUID EQUILIBRIA OF ORGANIC COMPOUNDS: MEASUREMENT,CORRELATION AND PREDICTION†

The knowledge of phase equilibria is an important step in the development of extraction processes. This knowledge is usually gained from experiments. However, this procedure is expensive when a suitable solvent has to be found for a specific separation. Therefore methods for predicting phase equilibria are needed. While formerly these methods were largely based on empirical assumptions, the use of the concept of local compositions by Wilson⁶ offers a semi-empirical approach.

There is one disadvantage of this approach: the parameters of models like UNIQUAC or NRTL have to be fitted to different types of data, to liquid-liquid equilibria (LLE) for the immiscible pairs of components and to vapour-liquid equilibria (VLE) or other data for the miscible pairs in a system with mutual solubility.

To demonstrate the problem we performed measurements in the binary systems: n-octane/aniline and methylcylohexane/aniline. of both liquid-liquid equilibrium and vapour-liquid equilibrium: for the second type of measurements ebulliomeiry was used. The prediction of LLE has been improved with two new concepts. One is based on the well-known UNIFAC method. The use of the Lyngby-Dorlmund data bank made it possible to determine a new parameter table merely based on LLE data.

The second method is based on common UNIQUAC parameters which have been determined with the data base.     

碳酸二甲酯-碳酸二乙酯-甲醇三元体系相平衡数据的推算

采用双循环汽液平衡釜测定了常压下碳酸二甲酯-碳酸二乙酯、碳酸二甲酯-甲醇、碳酸二乙酯-甲醇三组二元体系的汽液平衡数据,实验数据经Herington面积积分法检验符合热力学一致性。用Wilson模型分别对实验数据进行了关联,利用关联出的模型参数计算相应的汽相组成,并与实验值比较,二者符合良好。利用二元体系的汽液平衡数据,由Wilson方程推算了碳酸二甲酯-碳酸二乙酯-甲醇三元体系的汽液平衡数据。为建立碳酸二乙酯和碳酸二甲酯、甲醇的精馏分离数学模型提供了基础数据。     

N-甲酰吗啉与苯的二元等压汽液平衡

石化系统、焦化行业,采用N-甲酰吗啉（NFM）溶剂精制芳烃受到极大重视,但可资利用的基础数据却极为贫乏,尚无等压汽液平衡数据。用改进的EC-2型汽液平衡釜,测定了常压下苯-NFM、甲苯-NFM二元体系汽液平衡数据,并用 NRTL 和 UNIQUAC 模型对实验数据进行了关联,得到了模型相应的二元交互参数。经Herington 面积法检验,上述数据满足热力学一致性要求,结果较为满意。研究结果填补了该项数据空白,完全能满足N-甲酰吗啉溶剂精制芳烃工程设计的需要。     

顺丁烯二酸酐-邻苯二甲酸二丁酯二元体系的等温气液平衡

顺酐和其有机回收溶剂的气液平衡数据对开发新的顺酐生产回收工艺十分重要。利用改进的沸点仪测定了不同配料组成顺酐的邻苯二甲酸二丁酯溶液在413．15K、433．15K和453．15K下的平衡总压数据,结合所用沸点仪的平均滞流因子和物料衡算关系,采用NRTL模型关联推算得到顺酐和邻苯二甲酸二丁酯二元体系在上述三个温度下的气液平衡组成,并且给出了此二元系统的NRTL模型参数。