Measurement and estimation of the lower flash points for the flammable binary systems using a Tag open cup tester

Lower flash points for flammable binary systems, ethylbenzene+n-propanol, n-propionic acid+ethylbenzene and n-propionic acid+o-xylene, were measured by Tag open cup tester. These binary solutions exhibited the minimum flash point behavior, which leads to a minimum on the flash point vs composition curve. The experimental data were compared with the values calculated by the flash point prediction models based on the van Laar and Wilson equations. As can be seen from the A.A.D., the calculated values based on the Wilson equation were found to be better than those based on the van Laar equation.     

The lower flash points of binary systems containing non-flammable component

The lower flash points for two binary systems (water+acetic acid and water +propionic acid) containing non-flammable component were measured by Pensky-Martens closed cup tester. The experimental data were compared with the values calculated by the Van Laar and Wilson equations. Good qualitative agreement was obtained with these equations. However, the calculated values based on the Wilson equation were found to be better than those based on the Van Laar equation.     

二元有机混合液体闪点的实验研究

纯物质的闪点一般可通过查取文献获得,混合物的闪点则很难查到。由于混合液体在实际生产中有着广泛的应用,因此,掌握混合液体闪点的变化规律对于其在生产、储存和使用场所中的风险评估有重要意义。文中采用MINIFLASH FLPL全自动闪点测试仪,对由16种纯物质(包含醇类、酸类、酯类、酮类、醚类、烷烃类)组成的14组不同组成和配比的二元混合液体(含完全互溶和部分互溶)的闪点进行实验研究。用图示法分析了不同研究体系的二元有机混合物其闪点随配比和组分变化的经验规律,将二元混合液体闪点的变化规律大致划分为4类,并对每一类的闪点变化特征和机理进行了探讨。研究结果不仅为工程上提供了二元混合液体闪点的可靠实验数据,还为混合液体在生产、储存和使用过程中的火灾风险评估与安全管理提供了重要参考。     

Calculation of mixture equilibrium binary interaction parameters using closed cup flash point measurements

Proper design and operation of separation processes are highly dependent on phase equilibrium calculations. The common method to treat polar/nonpolar systems, and also mixtures of normal compounds where the sizes are significantly different is to use binary interaction parameters. This paper presents a method to calculate mixture binary interaction parameters using closed cup flash point measurements. The measured and literature closed cup flash points of different binary mixtures (ethanol + n-octane, 1-propanol + n-octane, 1-propanol + n-decane, n-octane + n-decane, 1-propanol + water, 1-butanol + n-octane, 2-butanol + n-octane, and water + propionic acid) are used to calculate binary interaction parameters. These binary interaction parameters together with common activity models are then used to calculate vapor–liquid equilibrium compositions of different binary mixtures considered in this study. The validity of the proposed method was successfully approved by comparing the calculated equilibrium compositions with experimental data.     

A study of interactions between soil fractions and PAH compounds in thermal desorption of contaminated soils

The interactions between three polynuclear aromatic hydrocarbons (PAHs), namely fluorene, naphthalene and anthracene, and three fractions of a soil, namely fulvic acid (FA), humic acid (HA) and humin/inorganic fractions, were studied experimentally. Prepared PAH + soil fraction binary mixtures, with PAH concentrations ranging over 0.8–7 mass%, were tested using a differential scanning calorimeter (DSC) over a temperature range of 20?390°C. The DSC thermograms for the PAH + HA mixtures showed distinctly different characteristics compared to mixtures with the other two soil fractions, where the endothermic peak for the vaporization of the PAH was absent. With the aid of vapour-liquid flash calculations, the lack of the boiling point peak is interpreted to be due to the liquid-phase miscibility of the PAHs and the HA fraction. Implications of the DSC results on the design and performance of the thermal desorption process are discussed.     

Ignition temperature of coal. 2. Binary coal mixtures

The ignition temperature of binary coal mixtures is determined. The mixtures contain coal of different metamorphic development, in various proportions. Systematic deviation of the actual ignition temperature from the values calculated on the basis of the sum rule is observed; the actual ignition temperature is lower. Statistical analysis shows that these deviations are significantly nonrandom. A formula is derived for predicting the ignition temperature of 50 : 50 binary mixtures on the basis of the ignition temperatures of their components. It appears that, in the mixtures, the component with the lower ignition temperature is ignited first. The energy liberated is consumed in the ignition of the less flammable component. That results in ignition of the mixture as a whole.     

混合制冷工质核态沸腾的传热研究

Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients.     

甲基二氯硅烷-甲基乙烯基二氯硅烷-甲苯三元体系等压汽液平衡

Vapor-liquid euilibrium (VLE) for a ternary system of Methyldichlorosilane methylvinyldichlorosilane toluene and constituent binary systems were measured at 101.3kPa using a new type of magnetical pump-ebulliometer,The equilibrium conpositions of the vapor phase of binary systems were calculated indirectly from the total pressure-temperature-liquid composition(pTx).The experimental data were correlated with the Wilson and NRTL(non-random two liquid )equations.The parameters of the Wilson moldel were employed to predict the ternary VLE data .The calculated boiling points were in good agreement with the experimental ones.     

二硫化碳生产装置消防初探

二硫化碳为低闪点易燃液体,具有易燃、易爆、高毒、高挥发性,其蒸气与空气形成爆炸性混合物,遇明火、高温极易燃烧爆炸,与氧化剂能发生强烈反应,其蒸气比空气重,能在较低处扩散到相当远的地方,遇火源引着回燃。若遇高温,容器内压力增大,有开裂和爆炸的危险。二硫化碳一旦泄漏,需用大量水封其泄漏产品,发生火灾时,需用水、泡沫、干粉、砂土等灭火。     

Correlations for prediction of diffusion in liquids

Based on an extensive experimental data collection (about 1925 points), empirical correlations for the estimation of binary liquid diffusion coefficients have been developed. The new correlations for organic mixtures and for aqueous solutions (including dissolved gases) require only well known and simple parameters like the viscosity of the solvent and the molar volumes of solute and solvent at the normal boiling point. They are shown to predict the limiting diffusion coefficients with the same or sometimes better accuracy than established correlations which make use of additional parameters. The concentration dependence of the mutual diffusion coefficients can be estimated from the knowledge of the two limiting diffusion coefficients and thermodynamic data. Established equations are investigated and classified for different groups of systems e.g. nonpolar + nonpolar, nonpolar + polar and polar + polar liquid mixtures.     

Determination and correlation solubility of m-phenylenediamine in (methanol,ethanol, acetonitrile and water) and their binary solvents from 278.15 K to 313.15 K

In this study, the solubility of m-phenylenediamine in four pure solvents(methanol, ethanol, acetonitrile and water) and three binary solvent(methanol + water),(ethanol + water) and(acetonitrile + water) systems were determined in the temperature ranging from 278.15 K to 313.15 K by using the gravimetric method under atmospheric pressure. In the temperature range of 278.15 K to 313.15 K, the mole fraction solubility values of m-phenylenediamine in water, methanol, ethanol, and acetonitrile are 0.0093–0.1533, 0.1668–0.5589,0.1072–0.5356, and 0.1717–0.6438, respectively. At constant temperature and solvent composition, the mole fraction solubility of o-phenylenediamine in four pure solvents was increased as the following order:water b ethanol b methanol b acetonitrile; and in the three binary solvent mixtures could be ranked as follows:(ethanol + water) b(methanol + water) b(acetonitrile + water). The relationship between the experimental temperature and the solubility of m-phenylenediamine was revealed as follows: the solubility of mphenylenediamine in pure and binary solvents could be increased with the increase of temperature. The experimental values were correlated with the Jouyban–Acree model, van't Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree model, Sun model and Ma model. The standard dissolution enthalpy, standard dissolution entropy and the Gibbs energy were calculated based on the experimental solubility data. In the binary solvent mixtures, the dissolution of m-phenylenediamine could be an endothermic process. The solubility data,correlation equations and thermodynamic property obtained from this study would be invoked as basic data and models regarding the purification and crystallization process of m-phenylenediamine.     

非电解质水溶液黏度的关联

许多化工过程的设计需要估算含水体系的黏度,但目前的黏度关联方法用于含水体系时误差较大.今以作者所在课题组近期提出的非水液体混合物黏度关联方程为基础,通过引入形状因子,得出了一个非电解质水溶液的黏度方程.该方程可用于二元非电解质水溶液黏度的关联,且能利用二元黏度得到的关联参数推算三元非电解质水溶液的黏度.该方程对54个二元非电解质水溶液体系黏度(总计2876个黏度数据点)关联的总平均相对偏差为4.60%;对7个三元非电解质水溶液体系黏度(总计352个黏度数据点)推算的总平均相对偏差为3.75%.结果表明,该方程具有较高的关联精度和推算精度.     

Association effects in ternary vapour—liquid equilibria

A thermodynamic model is proposed for the analysis of multicomponent systems capable of homo and heteroassociation between all the chemical species present. Detailed equations have been developed for ternary systems. The method has been applied to the experimental vapour—liquid data obtained for the system formic acid—acetic acid—propionic acid at 760 mm Hg. The calculated activity coefficients were thermodynamically consistent and were correlated using the Redlich—Kister equation. Boiling points, compositions and activity coefficients can be predicted from the vapour—liquid equilibrium data of the three binary systems.     

3-庚3-庚酮+乙酸乙酯、3-庚酮+乙酸丁酯、3-庚酮+TBP、MIBK+TBP二元体系的过量摩尔体积和黏度

常压下测定了3-庚酮+乙酸乙酯、3-庚酮+乙酸丁酯、3-庚酮+磷酸三丁酯（TBP）、4-甲基-2-戊酮（MIBK）+磷酸三丁酯4个二元体系在293.15～318.15 K下的密度和黏度值,计算了二元体系的过量摩尔体积V^E和过量黏度Δη,并用Redlich-Kister方程对V^E和Δη进行了关联。混合溶剂的黏度数据采用Orrick-Erbar(O-E)基团贡献法进行了关联和预测,增加了O-E方法中的(-O)₃-P=O 基团贡献值。结果表明,O-E方法可根据现有的纯溶剂的黏度数据预测得到混合溶剂的黏度,平均误差小于15%。     

Single component and competitive adsorption of propane, carbon dioxide and butane on Vycor glass

Equilibrium of gas phase adsorption on Vycor glass has been investigated. Adsorption isotherms for propane, carbon dioxide and butane as pure gases, binary mixtures and ternary mixtures were determined experimentally as a function of temperature using a volumetric method. The single-component isotherms were described with the Langmuir and Freundlich equations. Additionally, a second order isotherm based on statistical thermodynamics and an isotherm equation based on vacancy solution theory taking into account real phase behavior were used for fitting single-component equilibrium data. In order to describe the measured partial isotherms for binary mixtures, at first simple extensions of the single-component isotherm models were used, i.e., the conventional competitive Langmuir model and a multi-Freundlich equation based on the ideal adsorbed solution theory (IAS). Since these two simple isotherm models failed to represent the unusual competitive behavior observed, three model extensions using additional mixture parameters were applied, i.e., two modified multi-Langmuir equations based on: (a) statistical thermodynamics and (b) vacancy solution theory and a modified multi-Freundlich IAS model correcting spreading pressure uncertainties. These three model equations were found to be capable to describe the observed behavior better. Finally, the measured partial adsorption equilibrium data of the ternary system were correlated based on the extended equations using the determined additional binary parameters. The results obtained reveal the difficulty to predict accurately multi-component adsorption equilibria.     

Correlation of the boiling points of mixtures

A modified Swietoslawski equation has been developed to correlate the boiling points of mixtures. Vapor—liquid equilibrium data have been determined at 760 mm for the binary systems normal butanol-tertiary butanol and normal butanol-secondary butanol. Both systems present slight negative deviations from ideal solution behavior. The boiling points of the two binaries and of several other non-ideal systems were satisfactorily correlated by means of the above equation. Prediction of ternary boiling points from binary data and simplifications in the correlation which are useful for practical applications are also discussed.     

甲醇-乙酸、甲醇-丙酸和乙酸-丙酸二元体系汽液平衡

用新型泵式沸点仪测定了101.325 kPa下甲醇-乙酸、甲醇-丙酸和乙酸-丙酸3个二元系在不同液相组成时的沸点,用过量自由能函数Q,采用间接法由Tpx推算了3个二元体系的汽相平衡组成y。3个二元体系活度系数分别用Wilson模型、NRTL模型、Margules模型和Van Laar模型进行关联,用最小二乘法求出了它们的液相活度系数模型参数。用所得的液相活度系数来计算此二元体系的过量吉布斯自由能函数GE/(RT)。用3个二元系模型参数对所测的数据进行关联,建立该系统汽液平衡的热力学模型并计算平衡时的泡点温度。计算的泡点与实验的沸点吻合良好,经面积积分法检验,这些模型参数计算的3个二元体系相平衡数据具有很好的热力学一致性。     

二溴苯物系固液平衡测定与正规溶液模型

采用差示扫描量热法测定了邻二溴苯与间二溴苯、对二溴苯与间二溴苯和对二溴苯与邻二溴苯的3个二元固液平衡数据,同时绘制出相应的简单低共熔型二元相图。各物系低共熔摩尔分数组成和温度分别为：邻二溴苯(x) 间二溴苯(1-x),x=0.4485,t=240．4K;对二溴苯(x) 间二溴苯(1-x),x=0.1002,T=260.9K：对二溴苯(x) 邻二溴苯(1—x),x=0.1306,T=272.3K。采用单参数正规溶液模型计算,温度均方根偏差不大于1.1K,说明正规溶液模型适用于上述弱极性异构体物系固液平衡计算．     

An improved algorithm for the three‐fluid‐phase VLLE flash calculation

The VLLE flash is important in water and hydrocarbons mixtures, hydrocarbon and CO₂ rich mixtures, and hydrocarbon methane rich mixtures that are encountered in reservoir performance and recovery studies. A robust VLLE flash algorithm is proposed. The equilibrium and mass balance equations are solved as a constrained minimization problem. An inverse barrier function is used to handle the inequality constrains to solve for the phase fractions. It warrants always arriving to the solution. The challenging cases analyzed showed that the initialization procedure proposed, together with successive substitution iteration in the outer loop, is a good method for a stable VLLE flash algorithm, even near critical points. Whenever the result is in the region outside the three‐phase physical domain, the solution suggests that the system has fewer phases. In one of the cases analyzed, a region with three liquid phases was encountered and the algorithm found two different solutions with positive phase fractions. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3081–3093, 2015