Peng-Robinson状态方程计算合氢系统汽液平衡——超临界气体的参数处理

本文修正了Peng-Robinson 状态方程,使之适用于氢烃二元系统的汽-液平衡计算.对超临界气体氢引入了新的、随温度而变的a表达式和协体积项b的二元交互作用参数.计算了19个二元系统,结果表明本研究较前人为优.尤其是对氢-重烃(C_6-C_(16)),亦优于Mathias修正的Redlich-Kwong-Soave状态方程和Chao等人最近提出的立方型转子链状态方程(CCOR状态方程).修正后的a表达式除改进了汽液平衡结果,还可准确地推算氢气的P-V-T关系和第二维里系数.本研究推荐的方法可用于实际工程计算.     

局部组成型的立方转子链状态方程

为进一步改进立方转子链状态方程对混合物汽-液平衡的描述,作者建立了以局部组成概念为基础的新的混合物状态方程,并对42组低压和高压二元汽-液平衡数据(大多为极性体系)进行了关联.结果表明本模型较常规二次混合规则可显著提高关联的精确度并扩大应用范围.当应用于低压强极性体系时,一般可取得优于目前广泛使用的活度系数法所获得的结果.     

用改进的Martin-Hou状态方程预测C_5烃汽-液平衡

用改进的Martin-Hou状态方程及其混合规则,计算出C_5烃6个组分的Martin-Hou方程特征常数,并由该常数预测了常压下6个C_5烃二元体系的汽-液平衡关系,其结果与文献值比较,汽相组成绝对误差和温度相对误差的平均值分别为0.013和0.0016。     

气体在含盐非水溶液中的溶解度——CO_2-CuAlCl_4·(C_6H_5CH_3)_n体系的气-液平衡

本文提出了拟二元模型和状态方程联用的方法,计算加压情况下CO_2-CuAlCl_4·(C_6H_5CH_3)_n体系的气-液平衡数据.选用拟一元模型得到的CuAlCl_4·(C_6H_5CH_3)_n的表观临界参数和表观偏心因子作为状态方程中含盐非水溶液的特征参数.由实测的气-液平衡数据拟合了状态方程中的二元可调参数.考察了两种混合规则对计算精度的影响,发现修正混合规则后的P-R方程比原始的P-R方程具有更高的关联精度.计算表明,能用拟二元模型和状态方程来描述该体系的气-液平衡关系.     

含氟烷烃和含氟烯烃汽液平衡研究进展

综述了氢氟烃(HFCs)、氯氟烃(CFCs)和氢氯氟烃(HCFCs)3种含氟烷烃类和含氟烯烃类的汽液平衡研究进展,对文献中的实验测定及数据处理方法进行了简要分析。分析表明:研究者广泛采用静态法对汽液平衡数据进行测定,多采用PR、SRK和Lee-Kesler等状态方程,同时结合WS和vdW混合规则对数据进行关联拟合,且拟合效果较好。HFCs类汽液平衡数据的测定工作占据多数,含氟烯烃类的汽液平衡研究仍有较大的空间。     

烃-醇系混合热的测量和汽液平衡数据的推算

用PICKER动态型微量热计测量了三个温度下八个烃-醇二元系的混合热数据.提出了一个研究烃-醇系热力学性质的新的热力学模型——拟化学溶液模型(QCSM),用该模型关联了混合热实验数据和部分体系的等温汽液平衡数据,计算值和实验值间符合良好.以混合热拟合得到的QCSM参数及其与温度的关系式,推算了8个烃-醇二元系的244个等温或等压汽液平衡数据,获得了满意的结果.汽相摩尔分数的平均误差为0.004—0.032.     

立方型状态方程含过量自由焓模型的新混合规则

提出了在参考压力下将过量自由焓(g~E)模型引入状态方程的修正Huron-Vidal混合规则,由g~E模型确定状态方程中混合物的参数,以SRK方程和Wilson模型为例,取大气压为参考压力,计算了16个体系50组汽液平衡,结果表明本文建议的混合规则可直接使用现有文献报道的常压g~E模型参数由立方型状态方程预测常压汽液平衡,并对直接外推预测高压汽液平衡作了尝试.     

Peng-Robinson状态方程及保形溶液混合规则用于汽-液平衡计算

Peng-Robinson状态方程式用于推算三组二元系统的汽-液平衡:甲烷、二氧化碳及氢与烃类.对含甲烷及二氧化碳的二元系统.推荐了经过关联的相互作用参数.将保形溶液(Conformal Solu-tion)混合规则及本文提出的对温度有关的系数α的修正式应用于高度非对称的含氢二元系统,较Peng-Robinson的原始工作更为精确地表述了汽-液平衡.     

M—H状态方程计算氟氯烷体系的汽液平衡

对马丁-侯状态方程式进行修改,使其应用范围扩展到液相,对其用于计算汽液平衡的热力学可行性作了论述,并探讨了M-H状态方程常数的混合法则并得出了逸度系数的表达式,该方程用来计算四个氟氯烷二元体系的汽液平衡,与文献值符合是好的。     

若干含氢系统的汽液平衡

本文提出将PR方程用于含氢的非烃类系统中,并列举了计算汽液平衡的全部公式。氢的偏心因子值可按定义式求出,但在二元系统中,可取虚拟值ωH=-0.142。利用参数优化法求出二元系统的二元相互作用系数δ_(ij),六个含氢和六个不含氢的二元系统用本法计算表明,其平衡常数和露点的误差都较小。     

Vapor-liquid equilibrium correlations for systems containing amines using a lattice fluid equation of state with hydrogen bonding

The nonrandom lattice equation of state with hydrogen bonding (NLF-HB EOS) was examined for the correlation of vapor-liquid equilibria (VLE) for binary amine and hydrocarbon mixture at various temperatures. For these mixtures, the consideration of hydrogen bondings in the lattice equation of state clearly improves the prediction for VLE. The amines were divided into four groups due to the different strength of the hydrogen bonding. For all groups, different hydrogen bonding parameters were obtained and evaluated. The effects of varying hydrogen bonding energies for NLF-HB EOS are discussed. For systems containing lower amines, the NLF-HB EOS showed excellent agreement with the experimental data. For the correlation of systems containing tertiary amine molecules, binary interaction parameter had to be involved instead of hydrogen bonding parameters.     

应用PSRK状态方程预测高压汽液平衡

为预测高压汽液平衡,将过量吉布斯自由能混合规则和UNIFAC活度系数模型与SRK状态方程相结合,建立基团贡献状态方程PSRK。利用该状态方程对5个体系在不同压力和温度下的汽液平衡数据进行了关联实验测定的汽相压力和汽相组成与计算结果相比所得的相对平均偏差分别为2．16％和1．01％。结果表明,PSRK状态方程可以成功地预测高压下汽液平衡,其精度高于MHV1和MHV2模型。     

超临界二氧化碳和醇类体系的相平衡计算

应用Peng-Robinson(P-R)状态方程对超临界CO2系统进行了相平衡模拟。对超临界CO2和醇类二元系统进行了汽液相平衡计算,结果表明,P-R状态方程模拟高压下CO2系统的相平衡具有较高的精度。     

盐对二元溶液相对挥发度的影响

对关联盐对二元溶液相对挥发度影响的Furter经验方程进行理论分析,假定盐分子与液体分子形成不挥发的溶剂化物,改变了溶液可挥发的自由浓度,从而推导出方程中参数与液相浓度及溶剂化数间的函数关系式:K=η[(C_1/x_1)-(C_2/x_2)]用甲醇-苯-碘化钠、甲醇-四氯化碳-碘化钠、甲醇-环己烷-碘化钠三体系的汽液平衡实验(760mm-Hg)进行检验,与理论分析结果符合较好.并对Furter方程使用中的特殊情况进行了探讨.     

A modification of Wong-Sandler mixing rule for the prediction of vapor-liquid equilibria in binary asymmetric systems

Systems consisting of light components and heavy hydrocarbons are highly asymmetric and industrially important. Design and control of facilities for separation and purification of such mixtures require vapor-liquid equilibrium data. Coupling of the cubic equation of state (EOS) with excess Gibbs energy models (EOS/G ^ex models) failed to represent the vapor-liquid equilibria (VLE) of such systems accurately. The main purpose of this work is to present a modification of Wong-Sandler mixing rule with using the composition dependent binary interaction parameter. Vaporliquid equilibria for 30 binary systems are calculated using the SRK equation of state with proposed model and Wong-Sandler mixing rule. Calculated pressures and mole fractions of vapor phase are compared with experimental data. The average absolute percentage deviation indicates that error involved in the application of modified Wong-Sandler model is less than Wong-Sandler model in most cases.     

Application of peng-Robinson equation to high-pressure aqueous systems containing gases and sodium chloride

A novel approach is proposed for modeling vapor-liquid equilibria in systems containing aqueous NaCl and supercritical gases. The Peng-Robinson equation of state is used for all species, with the salt treated as a hypothetical liquid component. To correctly model the highly non-ideal liquid solution, a two-fluid model is used for the mixing rules in the equation of state. Effective pure-component parameters are reported for NaCl as well as binary interaction parameters for all possible binaries. Representation of high-pressure phase equilibria data show good agreement with experimental data. The principal advantage of this approach is the ability to treat high pressure systems containing non-volatile salts, while maintaining the simplicity of a cubic equation of state.     

PR方程用于低温高压含氢体系汽液平衡计算和结果分析

本文用PR状态方程推算低温高压含氢体系汽液相平衡.在计算中,考虑了正、仲氢的转化,并且采用两种方法考虑了量子效应.结果表明比原PR方程更精确地描述了汽液平衡.     

Prediction of vapor-liquid equilibria by means of a modified clausius equation of state

The Clausius equation was modified for the calculation of vapor-liquid equilibria in binary and multicomponent systems. In the modification, the three parameters of the equation were considered temperature dependent. Molal volumes of saturated liquid and vapor together with the condition that the fugacities of the vapor and the liquid phase are equal at the condition of equilibrium were used for evaluating the parameters of pure components. Applications were made successfully to systems nitrogen-methane, nitrogen-oxygen, argon-oxygen, nitrogen-argon, argon-methane, carbon dioxide-hydrogen sulfide, carbon-dioxide-propane, hydrogen sulfide-n-butane and nitrogen-argon-oxygen.