甲基丙烯酸甲酯-甲醇体系的双溶剂萃取

针对甲基丙烯酸甲酯(MMA)-甲醇共沸体系,常规精馏难以分离。提出采用己烷-水双溶剂体系萃取分离MMA的新工艺。测定了不同温度下MMA(1)+甲醇(2)+正己烷(3)+水(4)、MMA(1)+甲醇(2)+环己烷(3)+水(4)两个体系的相平衡数据,考察了不同温度下溶剂正己烷/环己烷、水的用量对萃取分配系数和选择性系数的影响。在实验数据的基础上,进一步采用UNIQUAC模型对该体系的相平衡进行了拟合,获得了模型参数。     

聚甲氧基二甲醚+水+正己烷三元体系的液液相平衡

聚甲氧基二甲醚（PODE_n）是一种极具应用前景的清洁柴油调和组分。研究了293.15 K、常压下PODE₁+水+正己烷、PODE₂+水+正己烷、PODE₃+水+正己烷、PODE₄+水+正己烷这4组三元体系的液液相平衡。PODE₁-4组分的萃取选择性系数S远大于1,表明正己烷作为萃取剂从水溶液中萃取PODE_1-4是可行的;经Hand结线关联检验,各体系的相平衡数据具有较高的一致性;采用NRTL和UNIQUAC热力学模型对相平衡数据进行拟合,均方根差计算（RMSD）结果和三元相图分析结果表明NRTL和UNIQUAC都能较好地描述三元体系的液液相平衡。     

聚甲氧基二甲醚+水+正己烷三元体系的液液相平衡

聚甲氧基二甲醚(PODEn)是一种极具应用前景的清洁柴油调和组分。研究了293.15 K、常压下PODE_1+水+正己烷、PODE_2+水+正己烷、PODE_3+水+正己烷、PODE_4+水+正己烷这4组三元体系的液液相平衡。PODE_(1-4)组分的萃取选择性系数S远大于1,表明正己烷作为萃取剂从水溶液中萃取PODE_(1-4)是可行的;经Hand结线关联检验,各体系的相平衡数据具有较高的一致性;采用NRTL和UNIQUAC热力学模型对相平衡数据进行拟合,均方根差计算(RMSD)结果和三元相图分析结果表明NRTL和UNIQUAC都能较好地描述三元体系的液液相平衡。     

正己烷+苯甲醇,甲基环己烷+苯甲醇及甲基环戊烷+苯甲醇体系汽液平衡数据的测定与关联

使用Ellis汽液平衡釜测定常压下正己烷+苯甲醇,甲基环己烷+苯甲醇和甲基环戊烷+苯甲醇体系的汽液平衡数据,并对实验数据进行了热力学一致性检验,结果表明数据通过检验;此外,利用Wilson方程对实验数据进行关联,关联结果与实验数据吻合较好。基于关联的二元交互作用参数,本文借助流程模拟软件Aspen Plus,以苯甲醇为萃取剂,对正己烷+甲基环己烷和正己烷+甲基环戊烷两个体系进行萃取精馏模拟计算。结果表明,苯甲醇可作为正己烷+甲基环己烷分离的萃取剂,但不适于作为萃取剂分离正己烷+甲基环戊烷共沸体系。     

混合溶剂抽提甲基环己烷的溶剂性能

采用浊点法测定了甲基环己烷-庚烷-单-溶剂（N-甲基-吡咯烷酮,NMP）或混合溶剂（N-甲基-吡咯烷酮＋环西砜、苯甲醇＋环丁砜）的三元或四元体系在（25±0．1）℃下的液液分层曲线．结合体系的物性（如折光指数或比重）测定了各体系的结线数据．由实验数据计算得到的选择性系数、溶解度和容量等数据,可以初步评价单一溶剂以及混合溶剂体系萃取分离烷烃与环烷烃的基本性能．研究发现单一纯溶剂的选择性系数较小,但与环丁砜组成混合溶剂体系能在一定范围内提高选择性系数．苯甲醇与环丁砜混合溶剂体系的选择性系数、溶解度和容量优于相同质量组成的N-甲基-吡咯烷酮与环丁砜混合溶剂体系．     

加盐萃取-精馏耦合分离甲醇-甲苯的工艺研究

研究了加盐萃取分离甲醇-甲苯共沸体系,考察了盐水种类、用量、质量分数及萃取温度等因素对萃取效果的影响,计算了在各种萃取条件下甲醇和甲苯的分配系数。实验结果表明:CaCl2水溶液的萃取效果最好,在CaCl2水溶液质量分数为0.35、萃取温度40℃、溶剂比(体积比)1.5∶1的条件下,甲醇的分配系数为2.32,选择性系数为18 200。基于以上实验数据,回归得到了萃取液液相平衡常数与萃取温度关联式的模型参数。在此基础上,提出了加盐萃取-精馏耦合分离甲醇-甲苯3塔工艺流程,并利用Aspen Plus软件中的Extract模拟萃取塔、RadFrac模拟精馏塔,选用NRTL-HOC和ELECNRTL热力学模型,对提出的工艺进行模拟计算,得到了合适的工艺操作条件。模拟结果表明:当萃取塔理论板数为5块;甲醇回收塔理论板数为21块、回流比为1.8;甲苯回收塔理论板数为28块、回流比为2.4时,分离得到的甲醇和甲苯的质量分数分别为0.996和0.997。     

水-苯酚-碳酸二甲酯-正己烷液液相平衡的测定与关联

用绿色溶剂碳酸二甲酯（DMC）萃取苯酚废水消除二次污染问题。研究了20℃下的三元体系DMC-水-苯酚和四元体系DMC-正己烷-水-苯酚的液液萃取相平衡,用UNIFAC模型计算了DMC在液相中的活度系数。结果表明,苯酚在有机相和水相间的分配系数为常数,不随着水相苯酚浓度变化。当有机相初始DMC浓度不同时,分配系数不同,萃取溶剂相中初始DMC体积浓度由50％增加到80％时苯酚的分配系数由10增加到19左右。定义了新UNIFAC基团OCOO,用最小二乘法回归得到了OCOO与CH2、H2O、ACH、ACOH等基团间的相互作用参数。对三元和四元体系的液液相平衡进行了预测,结果表明得到的相互作用参数可以较好地对液液相平衡进行推算。     

正己烷–异丙醇共沸体系液液相平衡数据测定及关联

为了给溶剂萃取分离正己烷–异丙醇混合物的过程设计和流程模拟计算提供基础数据，以二甲亚砜、1,4-丁二醇、1,2-丙二醇、乙腈、糠醛和N,N-二甲基甲酰胺为萃取剂，测定了30℃下萃取分离正己烷–异丙醇混合物的液液相平衡数据，并利用分离因子评价不同萃取剂的萃取分离性能。根据Hand方程对实验数据进行一致性和可靠性检验，拟合方程的相关系数都在0.98以上。随后，采用Aspen Plus软件选取NRTL活度系数模型对相平衡数据进行关联，得到相应的二元交互作用参数，并以此计算相应的相平衡组成。结果显示，计算值和实验值的均方根偏差小于1.0%，表明NRTL模型能够准确描述三元体系的液液相平衡。     

基于CPA状态方程计算天然气-甲醇-水气液相平衡

采用考虑了极性分子间氢键缔合作用的立方型附加缔合项(CPA)状态方程计算了天然气-甲醇-水体系气液相平衡。根据实验测试的甲烷-水、乙烷-水、丙烷-水、正己烷-水、甲醇-水二元体系气液相平衡实验数据,拟合了CPA状态方程中甲烷、乙烷、丙烷、正己烷、甲醇与水的二元交互作用系数,提出了与烷烃摩尔质量相关的烷烃-水二元交互作用系数关联式。在此基础上,预测了天然气-甲醇-水多组分体系的气液相平衡。结果表明:在温度为283—298 K,压力为5.86—34.34 MPa的范围内,预测的气相水含量、甲醇含量与实验值之间的平均相对偏差分别为5.55%和8.09%。CPA状态方程不仅为准确预测天然气-甲醇-水体系的气液相平衡提供了依据,还可应用于其他含极性物质体系的热力学物性参数和相平衡的计算。     

甲基环己烷一正庚烷一混合溶剂体系的相平衡及溶剂抽提性能

测定了甲基环己烷一正庚烷一混合溶剂（环丁砜／苯甲醇及环丁砜／Ｎ一甲基一吡咯烷酮）体系在（３５±０．１）和（４５±０．１）℃下的液液分层曲线及各体系的结线数据,并计算得到了混合溶剂的选择性、溶解度等数据．初步讨论了以上混合溶剂体系萃取分离甲基环己烷与正庚烷的基本性能．结果表明,同一温度下质量组成相同的环丁砜／苯甲醇混合溶剂体系的选择性、溶解度等均较环丁砜／Ｎ一甲基一吡咯烷酮混合溶剂体系为优．结合２５℃时的数据,考察了温度对这些溶剂体系的选择性、溶解度等的影响,表明升高温度能提高溶剂的溶解能力,而选择性则有所降低．     

水-丙烯酸-醋酸-甲苯四元体系液液平衡数据的测定与关联

采用液液平衡釜,在常压下,测定了293.15,303.15,313.15 K时水-丙烯酸-醋酸-甲苯四元体系的液液平衡数据,为萃取-非均相共沸精馏法精制丙烯酸选择适宜的溶剂提供依据.使用Othmer-Tobias方程对实验数据进行线性拟合.分别采用非随机双液(NRTL)和通用似化学(UNlQUAC)活度系数模型对实验体...     

Measurements and thermodynamic modeling of liquid–liquid equilibria in ternary system 2-methoxy-2-methylpropane+p-cresol+water

Liquid–liquid equilibrium(LLE)data for the ternary system 2-methoxy-2-methylpropane(methyl tert-butyl ether)+ p-cresol + water was measured at atmospheric pressure and temperatures of 298.15 K and 313.15 K.From the distribution coefficients and selectivity,it was found that 2-methoxy-2-methylpropane is an efficient solvent to extract p-cresol from wastewater.The consistency of the experimental tie-line data was verified with the Hand and Bachman equations.These data were also correlated with the non-random two liquid(NRTL)and universal quasi-chemical correlation activity coefficient(UNIQUAC)models to yield binary interaction parameters for p-cresol extraction process evaluation.Both models agreed with experiments very well,yet the NRTL model showed even smaller average deviation than the UNIQUAC model.     

Process design and economic analysis of methacrylic acid extraction for three organic solvents

In this work, a techno-economic study for the solvent based extraction of methacrylic acid from an aqueous solution is presented. The involved phase equilibrium calculations in process design are verified by measured experimental data. First, experiments are conducted with different solvent candidates to measure LLE (liquid–liquid equilibrium) data and to establish the effects of extraction temperature and dosage of solvent. Next, the binary interaction parameters for the UNIQUAC model to be used for equilibrium calculations are fine-tuned with measured data. Then, a process for the solvent based extraction of methacrylic acid recovery is designed and verified through simulation with the regressed UNIQUAC model parameters. The optimal configuration of the process flowsheet is determined by minimizing the total annualized cost. Among the three solvent candidates considered-cyclohexane, hexane and toluene-the highest efficiency and the lowest total annualized cost is found with toluene as the solvent.     

Measurement and correlation of liquid-liquid equilibrium for the ternary system (water + 1,2-dichloroethane + sulfolane) at 288.15, 298.15, and 308.15 K

Sulfolane is an important aprotic polar solvent. Liquid-liquid equilibrium (LLE) data for the ternary systems of water + 1,2-dichloroethane + sulfolane were measured at temperatures of 288.15, 298.15 and 308.15 K under the atmospheric pressure. The distribution coefficient and selectivity were determined from the measured LLE data, which showed that 1,2-dichloroethane is a suitable extractant for the recovery of sulfolane from its aqueous solution. The nonrandom two-liquid (NRTL) model and the universal quasi-chemical (UNIQUAC) model were utilized to correlate the experimental LLE data. The low values of RMSD indicated that the ternary system could be fitted well by the NRTL and UNIQUAC models. The consistency of the binary interaction parameters for the two thermodynamic models obtained was confirmed by the topological information contained in the Gibbs energy of mixing function (G^M/RT).     

甲基异丙基甲酮-苯酚-对苯二酚-水的液液相平衡数据测定、模型关联及萃取过程模拟

液液相平衡测定为溶剂萃取及回收的准确模拟、设计和过程开发提供基础数据。以甲基异丙基甲酮为萃取剂,在处理高浓煤化工含酚废水的三元液液相平衡萃取基础上,选定其中典型单元酚苯酚和多元酚对苯二酚为代表物,测定甲基异丙基甲酮-苯酚-对苯二酚-水在常压40℃下的液液相平衡数据。采用NRTL和UNIQUAC活度系数模型对实验数据进行热力学关联,回归得到该四元体系的二元交互作用参数。结果表明该模型可以很好地关联实验数据,两种模型的相对均方根偏差分别小于0.190%和0.266%。进一步将得到的二元交互参数导入流程模拟系统,对萃取单元模块进行计算。当萃取温度40℃、萃取级数5级、相比1：7.72时,甲基异丙基甲酮能将总酚12700 mg×L^-1,多元酚4250 mg×L^-1的含酚废水的酚浓度分别降低至300 mg×L^-1和299 mg×L^-1以下。     

甲苯-正己烯-二甲基亚砜液-液平衡数据的测定与关联

裂解汽油是含有烯烃的重要芳烃资源,二甲基亚砜(DMSO)能够从高烯烃含量组分中选择性萃取芳烃,测定相应体系液-液平衡是裂解汽油中的芳烃萃取过程研究开发的理论基础。测定了常压下293.15、298.15、303.15 K时甲苯-正己烯-DMSO体系液-液平衡数据,获得了三元体系的相图和褶点,并采用Hand方程和NRTL方程进行关联。体系中甲苯对正己烯选择性系数为2～6,表明DMSO萃取分离甲苯和正己烯理论上可行。通过体系液-液平衡关联获得了NRTL方程模型参数,利用NRTL模型对该体系进行计算,计算值与实验值的平均偏差较小,说明NRTL模型适用于该体系的液-液平衡。     

Investigation of liquid–liquid equilibrium of the ternary system(water +1,6-diaminohexane + 2-methyl-1-propanol or 3-methyl-1-butanol) at different temperatures

In this study, the LLE data of ternary system (water+1,6-diaminohexane+2-methyl-1-propanol) and (water+1,6-diaminohexane+3-methyl-1-butanol) were measured at 293.15, 303.15 and 313.15 K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical Hand, Othmer-Tobias and Bachman equations. Distribution coefficient (D) and selectivity (S) were calculated in order to investigate capability of the studied organic solvents for 1,6-diaminohexane extraction. The high values of separation factors demonstrated that 2-methyl-1-propanol and 3-methyl-1-butanol were applicable for this purpose. The experimental data were correlated by nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models. The percent-root-mean-square deviation (RMSD) values for NRTL and UNIQUAC models were less than 0.15, which indicated that the experimental data have been sufficiently correlated.     

甲基丙烯酸甲酯-甲醇-水共沸体系萃取分离工艺模拟

针对甲基丙烯酸甲酯?甲醇?水共沸体系,分别选择水、正己烷和水?正己烷双溶剂为萃取剂建立分离流程进行模拟, 建立单溶剂、双溶剂萃取工艺过程进行全流程模拟,采用灵敏度分析优化工艺过程的溶剂比和操作温度. 结果表明,双溶剂萃取工艺比水、正己烷单溶剂萃取工艺能耗分别降低15.1%和34.9%. 采用绿色度评价方法量化3种分离工艺对环境的影响,水、正己烷、水?正己烷双溶剂萃取工艺的绿色度分别为–7.25, –21.3和–6.75 gd.     

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.