Process simulation using the expanded fluid model for viscosity calculations

The expanded fluid (EF) viscosity model was implemented and further developed for efficient integration into a commercial process simulator (VMGSim™). The model has three adjustable parameters per component and its inputs are density, pressure and low pressure gas viscosity. The model was adapted to use densities determined by the Rackett correlation (liquid phase) and the Advanced Peng–Robinson Equation of State (vapor phase). The enhanced EF model fit experimental viscosities of pure hydrocarbons, water and polar compounds important for the simulation of oil and natural gas systems with average absolute errors just above 5%. The implemented EF model was tested against experimental viscosity data that included hydrocarbon and aqueous mixtures with average absolutes errors of 0.7 and 6.2% respectively. Generalized expressions for the estimation interaction parameters of binary mixtures involving paraffins, naphthenes, aromatics, alcohols, glycols and water were obtained. The EF model was also applied to crude oil (bitumen) examples. The three key developments for the efficient implementation of the EF model in a commercial simulator were: (1) the appropriate selection of phase density models; (2) the automatic determination of model fluid specific parameters; and (3) the use of generalized mixing rules for the calculation of binary interaction parameters.     

Description of the mutual solubilities of fatty acids and water with the CPA EoS

Data for the mutual solubilities of fatty acid + water mixtures are scarce and so measurements for seven fatty acid (C₅‐C₁₀, C₁₂) + water systems were carried out. This new experimental data was successfully modelled with the cubic plus association EoS. Using data from C₆ to C₁₀ and the Elliot's cross‐associating combining rule a correlation for the k_ij binary interaction parameter, as a function of the acid chain length, is proposed. The mutual solubilities of water and fatty acids can be adequately described with average deviations inferior to 6% for the water rich phase and 30% for the acid rich phase. Furthermore, satisfactory predictions of solid‐liquid equilibria of seven fatty acids (C₁₂‐C₁₈) + water systems were achieved based only on the k_ij correlation obtained from liquid–liquid equilibria data. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Fluid phase behavior modeling of CO2 + molten polymer systems using cubic and theoretically based equations of state

Phase equilibrium data of CO₂ + molten polymer systems are of great relevance for chemical engineers because these are necessary for the optimal design of polymer final‐treatment processes. This kind of processes needs information about gas solubilities in polymers at several temperatures and pressures. In this work, CO₂ solubilities in molten polymers were modeled by the perturbed chain‐statistical associating fluid theory (PC‐SAFT) equation of state (EoS). For comparison, the solubilities were also calculated by the lattice gas theory (LGT) EoS, and by the well‐known Peng‐Robinson (PR) cubic EoS. To adjust the interactions between segments of mixtures, there were used classical mixing rules, with one adjustable temperature‐dependent binary parameter for the PC‐SAFT and PR EoS, and two adjustable binary parameters for the LGT EoS. The results were compared with experimental data obtained from literature. The results in terms of solubility pressure deviations indicate that the vapor–liquid behavior for CO₂ + polymer systems is better predicted by the PC‐SAFT model than by LGT and PR models. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.     

SOLUBILITY OF ACETAMINOPHEN AND IBUPROFEN IN BINARY AND TERNARY MIXTURES OF POLYETHYLENE GLYCOLS 200 AND 400, PROPYLENE GLYCOL,AND WATER AT 25°C

The solubilities of acetaminophen and ibuprofen in the mixtures of propylene glycol-water, polyethylene glycols 200- and 400-propylene glycol, and polyethylene glycols 200- and 400-propylene glycol-water (122 data points) at 25°C were determined and mathematically represented by the Jouyban-Acree model. The solubilities were measured using the shake flask method, and the model was used to fit the solubility data of each drug in the solvent mixtures. The density of the solute-free solvent mixtures was measured and the density of the drug-saturated solutions was predicted. The obtained overall mean relative deviations (OMRDs) for fitting the solubility data of acetaminophen and ibuprofen in binary mixtures are 1.5% and 11.7%, respectively. The OMRDs for fitting the solubilities in ternary solvent mixtures for acetaminophen and ibuprofen are 16.3% and 42.0%, respectively, and the OMRD values for predicting all solubilities of acetaminophen and ibuprofen by these trained versions of the Jouyban-Acree model were 5.7% and 20.4%, respectively. The prediction OMRD for the density of saturated solutions was 2.5%.     

乙醇胺乳酸盐离子液体吸收SO2过程中的物理化学性质

测定了常压下乙醇胺乳酸盐-水二元混合体系纯组分及混合液在303.15～333.15 K温度内的密度和黏度, 并对实验数据进行拟合, 通过Jouyban-Acree模型将密度、黏度数据与温度和组成进行关联, 得到关联参数。实验还测定了不同水分含量下该体系饱和吸收SO₂后的密度、黏度。结果表明:该二元混合体系的密度随着温度以及水含量的增大而下降;在水分含量低时该体系的黏度随着温度以及含水量的增大而急剧下降;在水分质量分数超过60%时, 含水量对黏度变化的影响较小。在相同条件下饱和吸收SO₂后, 该体系的密度和黏度比吸收前的略有增大。另外, 分别由密度和黏度实验数据计算不同温度及组成下该二元体系的超额摩尔体积V^E和混合黏度变化Δη, 结果均为负值, 产生了负偏差, 说明离子液体与水之间较强的相互作用。     

Solubility of Tadalafil in Pharmaceutical Solvent Mixtures at 298.2K

The experimental solubility of tadalafil in binary mixtures of ethanol (EtOH) + water, propylene glycol (PG) + water, polyethylene glycol 200 (PEG 200) + water, polyethylene glycol 400 (PEG 400) + water, and ternary mixtures of PEG 200 + PG + EtOH at 298.2 K were assessed. The experimental data were fitted to the Jouyban–Acree model. The mean percent deviations (MPD) of the back-calculated solubilities for EtOH + water, PG +water, PEG 200 + water, PEG 400 + water, and PEG 200 + PG + EtOH mixtures were 7.4%, 11.3%, 14.0%, 18.5%, and 5.6%, respectively and the overall MPD was 11.0%.     

缔合模型用于超临界萃取溶解度计算

基于在超临界萃取过程中,同时存在超临界流体相－固相相平衡和超临界相缔合反应平衡的假设,提出一一个用于超临界萃取溶解度计算的缔合模型。该模型式用于２７个固体溶质和５个液体溶质在超临界溶剂中溶解度的计算,其平均相对偏差绝大多数体系均小于１０％。     

离子液体[BMIM][DBP]+水+甲醇/乙醇三元工质溶液蒸汽压的测量和预测(英文)

The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1) + [BMIM][DBP](2) were measured at different temperature and in the ILs mole fraction range from 0.1 to 0.6 with a static equilibrium apparatus. The measured vapor pressures were correlated with Non-Random Two Liquid (NRTL) activity coefficient model and the average relative deviations (ARD) between experimental and correlated vapor pressures for these binary solutions were 3.19%, 2.42% and 2.95%, respectively. Then, the vapor pressures of two set of ternary solutions H2O(1) + CH3OH(2)/C2H5OH(2) + [BMIM][DBP](3) were measured with an inclined boiling apparatus and further predicted with NRTL activity coefficient model based on the binary interaction parameters coming from fitting the vapor pressures of the binary solutions. The results indicated that the ternary solutions containing [BMIM][DBP] were shown a strong negative deviation from Raoult’s Law when the mole fraction of [BMIM][DBP] was larger than 0.2, which meant that ternary solutions could absorb the refrigerant vapors at the same or below solution temperature. Meanwhile, the average relative deviations between experimental and predicted vapor pressures for ternary solutions were 2.92% and 3.06%, respectively. Consequently, the NRTL active coefficient model used for non-electrolyte solutions was still valid for predicting vapor-liquid equilibrium of binary or ternary solutions containing ILs.     

Measurement and Prediction of Vapor Pressure for H2O+CH3OH/C2H5OH+[BMIM][DBP] Ternary Working Fluids

The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1)+[BMIM][DBP](2) were measured...     

Measurement and correlation of solubility of trimethylolethane in different pure solvents and binary mixtures

The solubilities of trimethylolethane in butanol,methyl acetate,ethyl acetate as well as in mixed solvents of (methanol + ethyl acetate) and (ethanol + ethyl acetate) were measured with the gravimetTic method in the temperature range from 283.15 K to 318.15 K under atmosphere pressure.The experiment results showed that the solubility of trimethylolethane increased with the temperature,or along with the concentration of methanol or ethanol in the solvents of (methanol + ethyl acetate) and (ethanol + ethyl acetate).In addition,the experiment values were correlated by the van't Hoffequation,Modified Apelblat Equation,λh Equation,CNIBS/R-K equation and Jouyban-Acree Model.The Modified Apelblat Equation provided the best fitting results of the solubility data of TME in the pure solvents while the CNIBS/R-K model showed the best estimation of the solubility in the binary solvent mixtures.Furthermore,the density functional theory (DFT) calculations showed that solubility in different solvents related to the strength of the interaction between the trimethylolethane and the solvent molecules.Finally,the standard molar enthalpy and molar entropy of trimethylolethane during the dissolving process was also calculated by Modified Apelblat equation in this work.     

Phase equilibria of mixtures containing CO2 and organic acids using the UMR-PRU model

The UMR-PRU model, which has been successfully tested in the past to the predictions of different type of phase equilibrium and thermodynamic properties in binary and multicomponent systems, is applied in this work to phase equilibria in mixtures containing CO₂ and organic acids. New interaction parameters are determined by fitting only binary vapor–liquid equilibrium data and then they are used to predict the vapor–liquid, solid–gas and solid–liquid–gas equilibria in CO₂/organic acid systems. Furthermore, the UMR-PRU model with the newly derived interaction parameters is applied to the prediction of the phase equilibrium in ternary mixtures consisting of CO₂, organic acids and water. Satisfactory results are obtained in all cases.     

一氧化碳在苯酚+乙醇中的溶解度测量和关联

The solubility of carbon monoxide in phenol＋ethanol mixed solvents at elevated pressures is reported in this article. The experimental results revealed the influence of pressure on the solubility of CO in phenol＋ethanol mixtures. These mixtures are a poorer solvent for carbon monoxide. The solubility of CO is a linear function of pressure, and the extended Henry＇s constants were presented at different concentrations of phenol. The cubic Soave-Redlich-Kwong equation of state was used to correlate the experimental gas liquid equilibrium data and to predict the solubility of CO. At the same time, the binary interaction parameters, kO, for CO-phenol, CO-ethanol and phenol-ethanol systems were estimated by fitting experimental GLE data at 303.15 K and at 2.0-9.0 MPa. Hence, a model was suggested for the solubility of CO in phenol＋ethanol mixed solvents. The agreement between experimental and calculated solubilities with the proposed model was rather satisfactory.     

状态方程模拟醇胺系统的密度和汽液相平衡

通过考虑醇胺分子间的缔合作用,结合先前开发的非缔合变阱宽链流体状态方程(SWCF-VREOS)建立了一个缔合方阱链流体状态方程,并利用方程模拟了醇胺系统的密度和汽液相平衡。通过关联不同温度下醇胺的饱和蒸气压和液体体积得到了18种醇胺流体的分子参数,新方程计算的饱和蒸气压和液体密度总的平均误差分别为0.94%和0.88%。结合简单的混合规则,将此方程扩展到混合系统。研究发现,建立的方程可预测二元和三元醇胺混合物的密度。当引入一个与温度无关的可调参数时,方程能满意关联二元系统的汽液相平衡数据,并可进一步预测多元混合系统的汽液相平衡,预示着新方程可模拟醇胺系统的相行为。     

2,2-二甲基丁烷+乙醇、+正丙醇二元体系常压汽液平衡的测定

使用自行设计的汽液平衡釜测定了常压下2,2-二甲基丁烷+乙醇和2,2-二甲基丁烷+正丙醇二元体系的汽液平衡数据,所得到的汽液平衡数据通过了Herrington面积法热力学一致性检验。实验数据用NRTL方程进行关联,采用关联得到的模型参数计算相应的汽相组成,并与实验值比较。汽相组成的平均偏差小于0.02,这说明NRTL模型适用于所研究的二元体系。     

水合物法开发高寒地区湖盐设想相平衡验证

为了从相平衡条件角度验证气体水合物法开发我国高寒地区湖盐的设想,以van der Waals-Platteeuw模型为基础,结合杜亚和等提出的计算Langmuir常数的三参数方程和计算电解质溶液中水的活度的Pitzer方程,在国际上首次模拟了饱和NaCl溶液中一氟二氯乙烷(R141b)水合物的相平衡条件,并进行了实验验证。研究结果表明:10.1 kPa时饱和NaCl溶液中R141b水合物的生成温度为259.77 K,高于常压下饱和NaCl溶液凝固点250.81 K,也高于青海地区最冷月平均环境温度。因此,利用环境冷量实现气体水合物法节能开发我国高寒地区湖盐具备理论可能性。     

AN EQUATION OF STATE FOR AQUEOUS ELECTROLYTE SYSTEMS——Prediction of The Solubility of Natural Gas in Formation Water

A new equation of state(PHSMSA EOS)based on perturbation theory is developed for calculating high-pressure phase equilibria of aqueous electrolyte systems containing supercritical gases,light hydrocarbons andpolar components.The binary interaction parameters are determined:for ion-ion pairs by regression of ionicactivity coefficient data;for molecule-molecule pairs by fitting the VLE data of binary nonelectrolyte mixtures;and for ion-molecule pairs by fitting the gas solubility data of ternary gas-water-salt systems.The new EOShas been tested on the prediction of solubilities of methane,nitrogen and natural gas mixtures in brine.Sat-isfactory agreement with the experimental data measured by authors and other investigators is observed.     

基于黏滞球模型的CPA状态方程应用于醇胺系统相平衡的计算

考虑到醇胺及其混合物中分子间存在缔合作用的事实,结合立方型PR状态方程,通过引入基于黏滞球模型(SSM)发展起来的缔合流体的分子热力学模型,建立了一个新的CPA(cubic-plus-association)状态方程,即CPA-SSM,并将方程应用到醇胺系统相平衡的计算中。通过关联对比温度0.55～0.90范围下醇胺流体的实验饱和蒸气压和液相体积得到了8种醇胺流体的分子参数。结果表明,CPA-SSM方程可满意地计算出醇胺饱和蒸气压和液体密度,总平均误差分别只有0.57%和1.80%。对醇胺混合物,无论是恒压还是恒温系统,只需引入一个与温度无关的可调参数,CPA-SSM方程即可满意关联二元系统的汽液平衡数据,并可进一步预测多元混合物的汽液平衡。     

Correlation and prediction of synthesis gas solubility in n-paraffin systems

Fluctuation solution theory relates thermodynamics partial derivatives to integrals of molecular direct correlation functions from statistical mechanics. This paper describes an application of that theory for correlating and predicting solubilities of light gases in heavy n-paraffins. Two of the solvents are complex waxes. Equations from the theory represent the liquid phase, and additional hypothesis are adopted to build a model for the high pressure vapor-liquid equilibrium. In the correlation mode, the model, based in the fluctuation solution theory, produces a molar fraction of the gas in the liquid phase with an average absolute relative deviation under 3% in a large number of cases. In the prediction mode, when binary parameters are used, errors are on the order of 10%. Overall for n-paraffins solvents, the model presented in this paper shows a good capacity to correlate experimental solubility and an adequate power to extrapolate lower pressure data when a binary parameter value has been chosen.     

多室气升式环流反应器流动特性的数值模拟

在空气-水两相多室气升式环流反应器（MALR）中,采用欧拉欧拉两相流模型对扇形反应室内气液两相流动过程进行了数值模拟研究,考察了上升室的气含率、液体速度随表观气速的变化,最后用实验数据对模拟结果进行了验证.结果表明,某一上升室气含率受该室表观气速的影响较大,与另一上升室表观气速的影响较小;循环液体与上升室流体流动型式有关;气含率和循环液速的模拟值与实验值的平均相对误差分别为5.36％和8.28％;说明了应用数值模拟方法研究MALR流动特性的可行性.     

Isobaric Vapor-Liquid-Liquid Equilibria for 1-Butanol + Water + 2,3-Butanediol at 101.3 kPa

Vapor-liquid-liquid equilibria (VLLE) data were determined for the ternary system 1-butanol + water + 2,3-butanediol at 101.3 kPa. A binary heterogeneous minimum boiling azeotrope was found at 365.95 K with mass fractions of 0.526 and 0.474 for 1-butanol and water, respectively. A modified UNIQUAC model was used to predict VLLE by using experimental data, including VLE of 1-butanol + 2,3-butanediol, VLE of water + 2,3-butanediol, LLE of 1-butanol + water, and one LLE tie-line of 1-butanol + water + 2,3-butanediol. The experimental data were compared with the calculated values. The absolute average relative deviations (AARD) are 1.65%, 1.72%, and 2.22% for organic liquid phase, aqueous liquid phase, and vapor phase, respectively. It demonstrates an appropriate fit of the modified UNIQUAC model.