A generalized one-parameter redlich-kwong equation for vapor-liquid equilibrium calculations

The two modified parameters previously proposed for the Redlich-Kwong (RK) equation of state are simplified and reduced to a one-parameter model, and extended to vapor-liquid equilibrium (VLE) calculations involving supercritical components. However, the original RK parameters are still treated as temperature- and substance-dependent. In this investigation, this parameter is generalized in terms of T_r and Ω. The values obtained from the generalized correlation are suitable for calculating VLE data at T ≤ T_c for all components, and at temperatures where some of the components are in the supercritical region. The validity of the generalized correlation is supported by its ability to represent saturated properties of the pure components and to predict VLE data for five binary systems at 58 isothermal conditions, and one ternary system at two isothermal conditions.     

离子液体对乙腈-水共沸物系汽液平衡的影响

选择离子液体1-丁基-3-甲基咪唑氯盐（Bmin[Cl]）作为分离乙腈-水共沸物系的溶剂。在0.101MPa下测定了在离子液体Bmin[Cl]含量为10%、20%和30%时乙腈-水物系的汽液平衡数据。实验结果表明,离子液体Bmin[Cl] 可以提高乙腈对水的相对挥发度,离子液体Bmin[Cl]含量在20%以上时可以消除乙腈-水物系的共沸点。离子液体Bmin[Cl]可以用作分离乙腈-水物系的萃取剂。用改进的Furter方程对数据进行了关联,得到了离子液体Bmin[Cl]对乙腈-水物系的盐效应参数。     

汽液相平衡研究进展

概述了近年来汽液相平衡的测定方法:直接法(蒸馏法、静态法、流动法、循环法、泡露点法),间接法(饱和蒸汽压法、沸点仪法)和汽液相平衡计算方法(状态方程法和基团贡献法)的研究现状及其发展趋势,对其进一步的研究做了展望。     

The dynamic approximation method of handling vapor-liquid equilibrium data in computer calculations for chemical processes

The major cost in computer time for process simulation is incurred by the generation of K values. This paper describes the development of an interpolative or approximation algorithm for use in conjunction with a more accurate K value generator. Traditionally, a modular sequential process simulator iterates around the flow-sheet to a converged solution. Using our approach, the first two iterations use the accurate K value generator to set up the coefficients in an interpolative formula which is then used for successive iterations until a pre-specified convergence is attained. A final iteration is then carried out using the accurate K value generator.Tests indicate savings of up to 50% of the total simulation computer time cost.     

汽液双循环相平衡测定装置

建立了一套汽液双循环相平衡实验测定装置,并采用了磁力循环泵循环汽液两相流体、六通阀在线取样分析样品。装置具有平衡时间短、对测定体系和条件适应性广的特点。用已知体系的汽液平衡数据验证了装置的可靠性。并测定了正戊烷-苯体系30℃和55℃的等温汽液相平衡数据,用W ilson和NRTL活度系数方程对测定的汽液相平衡数据进行了关联,W ilson方程的汽相组成平均误差为0.006 5,NRTL方程的平均误差为0.007 3。     

汽液相平衡计算方法的研究进展

主要介绍了汽液相平衡计算的两种方法的研究进展,包括状态方程法和活度系数法.分析了方法中所涉及的各种方程的适用范围及其优缺点,提出了汽液相平衡计算的研究方向.     

流体汽液相平衡混合规则研究进展

混合工质汽液相平衡学术内涵丰富且应用广泛，而混合规则是决定混合物性描述准确与否的关键因素。综述了具有代表性的混合规则，包括原始的二次型、非二次型、密度型、状态方程-超额自由能型等混合规则，评价了其在流体汽液相平衡的描述能力，辅以数学推导介绍了其发展的动机及存在的优劣，以期对将来混合规则发展提供思路。     

乙酸异丙烯酯-乙酰丙酮汽液相平衡研究

为了给乙酸异丙烯酯(IPA)异构化生产乙酰丙酮(AA)工艺的产物分离设计提供基础热力学数据,用埃利斯(Ellis)平衡蒸馏器测定了101.3 kPa下乙酸异丙烯酯-乙酰丙酮体系的汽液平衡数据,结果表明,该二元体系未形成共沸物,实验数据通过了Herrington面积法的热力学一致性检验。分别采用Wilson方程和NRTL方程对实验数据进行了关联,计算结果与实验数据均较为吻合,其中NRTL模型的关联结果较好,乙酸异丙烯酯汽相摩尔分数的最大偏差为0.0036,平均偏差为0.0010。同时关联得到了2个方程的模型参数,满足了工程设计的需要。     

ω-Alkyl-ω-Nitroacetophenones

Nitroketones of the formula Ar. CO. CHR. NO₂ are best obtained by chromic acid oxidation of the easily accessible corresponding nitroalcohols. The nitroketones form stable salts with secondary amines. A series of ω-nitro-ω-(2-furfurylidene) - acetophenones has been synthesized. The infrared spectra of the new compounds prepared have been determined and are discussed.     

苯和N-甲酰吗啉的气液相平衡研究

常压下实测苯和N-甲(酉先)吗啉气液相平衡数据,利用Wilson方程和NRTL方程对数据进行关联.结果表明,苯和N-甲(酉先)吗啉二元体系有很好的相关性.又对气液相平衡数据进行了热力学一致性检验,结果合理.     

Application of wilsonés equation to determination of vapor-liquid equilibrium data and heats of mixing for non-ideal solutions

A calculation technique, starting from total pressure data of binary systems and utilizing Wilsonés equation was developed, leading to isothermal vapor liquid equilibrium data for binary and ternary systems. Heats of mixing for ternary systems were also calculated from binary data.     

水盐体系汽液平衡的热力学模型研究

水盐体系的相平衡性质是化工单元操作的基础,在化学化工、海洋、地质等领域有着重要的研究价值。国内外许多学者对水盐体系汽液平衡进行了实验和理论的研究,构筑了各具特色的经验和半经验的模型。针对水盐体系,在NRTL理论的基础上,基于水化作用和混合盐假设建立了能够预测混合体系汽液平衡的活度系数扩展模型。通过对21组二元水盐体系和14组混合体系的关联计算,验证了该模型的可行性;同时,该模型可以采用二元体系参数直接预测计算混合水盐体系汽液平衡。     

甲酸-水-甲酸丁酯体系的等压汽液相平衡研究

用改进的Rose釜测定了101.33 kPa下甲酸-水、甲酸-甲酸丁酯、甲酸-水-甲酸丁酯(互溶区内)的等压汽液相平衡数据。考虑了甲酸在汽相中的缔合效应和非理想性,用Hayden-O’connell关联式修正了汽相的非理想性,用NRTL模型对甲酸-水和甲酸-甲酸丁酯体系的汽液平衡数据进行了关联,得到了相应的模型参数。利用得到的二元体系模型参数,结合部分三元体系汽液平衡数据,关联得到水-甲酸丁酯体系的模型参数。由关联得到的3对二元NRTL模型参数预测三元体系汽液平衡数据,温度平均偏差为1.20℃,甲酸的汽相平均偏差为0.0152,甲酸丁酯的汽相平均偏差为0.0184,实验值与预测值基本吻合。     

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。     

Isobaric vapor-liquid equilibrium for methanol+benzene+1-octyl-3-methylimidazolium tetrafluoroborate

Isobaric vapor-liquid equilibrium (VLE) data for {methanol (1)+benzene (2)+1-octyl-3-methylimidazolium tetrafluoroborate (3)} where 3 is an ionic liquid ([OMIM]⁺[BF₄]^?) at atmospheric pressure (101.32 kPa) were measured with a modified Othmer still. The results showed that the ionic liquid studied can transfer the azeotropic point and eliminate the azeotropic phenomena when its concentration is up to x₃=0.30. This means that [OMIM]⁺[BF₄]^? can be used as a promising entrainer in the application of extractive distillation. The measured ternary data were correlated using the NRTL model.     

活性填料对乙酸乙酯-乙醇共沸物气液平衡的影响

为高效分离乙酸乙酯-乙醇共沸物,实验测定了乙酸乙酯-乙醇溶液在常压下气液平衡数据和活性毛细管填料对其的影响,为活性填料毛细管精馏高效分离共沸物提供了依据。首先测定了无填料时乙酸乙酯-乙醇二元气液平衡数据,经Herington面积法检验,符合热力学一致性;用热力学模型关联,效果良好;然后加入活性氧化铝、椰壳活性炭和13X分子筛,测定不同种类和不同含量的活性填料对乙酸乙酯-乙醇气液平衡数据的影响,结果表明:13X分子筛对乙酸乙酯-乙醇气液平衡数据基本无影响;椰壳活性炭影响居中;活性氧化铝影响最大,可将乙酸乙酯的共沸摩尔组成从0. 54提高到0. 77。由此可知,活性氧化铝有利于乙酸乙酯-乙醇共沸物的分离。     

莰烯+(+)-3-蒈烯体系汽液平衡数据的测定与关联

改进了Ellis平衡釜的保温、搅拌与压力控制系统，建立了一套可视窗口的实验装置。测定了莰烯+(+)-3-蒈烯体系在313.15、373.15和433.15 K下的汽液平衡数据；采用面积法和Van Ness检验法对实验数据进行热力学一致性检验，所有数据均符合Gibbs-Duhenm的热力学一致性；选用Aspen plus软件中NRTL、Wilson和UNIQUAC模型，由最大似然法对目标函数进行优化，实现对实验数据的关联。结果表明，气相组成和平衡压力的估算值与实验值的最大平均相对偏差为0.0128和0.0009，最大均方根偏差为0.0003和0.0012 kPa，相对挥发度的估算值与实验值的绝对平均偏差分别为0.09%、0.03%和0.04%。