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本文就十三个体系研究了色谱斜率法VG公式的适用条件.结果表明,除了该公式本身要求实验柱温在溶质沸点附近外,VLE预测结果还取决于过量自由焓模型的选择.对于使用UNIQUAC方程,在溶质沸点以下0~5.5℃的温度范围内可获得满意的VLE预测结果,对于Wilson方程,如果在求解Wilson参数的过程中不出现多解,则在溶质沸点以下3~5℃的温度范围内可获得满意的VLE预测结果.不论对UNIQUAC方程还是Wilson方程,一旦在求解方程参数的过程中出现多解,则应用本文所提出的“最小解原则”可以很好地进行VLE预测. 相似文献
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STUDY ON CHROMATOGRAPHIC SLOPE METHOD FOR REDUCING PARAMETERS OF EXCESS GIBBS ENERGY MODELS
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Two equations of (γ/χ)χ=0 ——a modified Kikic-Renon equation and a Valentin-Guiochon equation——have been studied. Values of γ_1~∞ and (dlnγ_1/dχ_1)χ=0 by these two equations for 29 binary systems have been calculated from GLC data, the parameters in some models of excess Gibbs free energy evaluated and the vapor-liquid equilibrium date predicted. The results are satisfactory. 相似文献
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运用Gibbs自由能最小化方法模拟气流床煤气化炉 总被引:23,自引:0,他引:23
基于 Aspen Plus工业系统流程模拟软件 ,运用 Gibbs自由能最小化方法建立了气流床煤气化炉的模型 .研究了气化炉的主要操作参数 (即水煤浆浓度、氧煤比、碳转化率和气化温度 )对气化结果的影响 .对模拟结果进行了分析 ,发现模型基本正确 ,可应用于一些反应机理复杂的气化工艺的化学和热力学平衡计算 .模拟结果表明 ,氧煤比和水煤浆浓度是影响气化炉出口煤气组成的主要因素 ,气化炉温度随着氧煤比的增加而增加 ,也随着水煤浆浓度的增加而增加 .结果还表明 ,氧煤比对气化结果的影响比水煤浆浓度的影响更为显著 相似文献
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鉴于活度系数与内压密切相关 ,修正了熟知的vanLaar理论 ,用Frank关系式替代了原理论推导中的vanderWaals流体内压 ,从而导得一个十分类似于Wohl方程的过量函数式 ,vanLaar方程、溶解度参数方程、Margules方程和Scatchard -Hamer方程等都是它的特例 .通过对过量熵贡献的修正 ,建立了一个活度系数方程 .它已被证明具有通用性 ,即不仅适用于各种小分子液体混合物 ,而且亦适用于各种高分子溶液 ,有比局部组成型方程更广的适用范围 .此外 ,由该Gibbs自由能模型还得到了溶解度参数一个新的定义 ,它比Hildebrand定义的溶解度参数更加广义 . 相似文献
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应用作者提出的逐级取样方法于NPT正则系综,提出了有效求取流体混合物超额Gibbs自由能的模拟方法。应用该方法模拟了Ar-Kr二元流体混合物、求得了T=115.8K,P=0时整个组成范围的超额Gibbs自由能,这些结果与McDonald采用常规NPTMonteCarlo模拟方法得到的近似结果在误差范围内相符。在交叉势能混合参数ζ=0.989时,模拟结果与实验结果一致。 相似文献
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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. 相似文献
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D.A. Jonah 《Chemical Engineering Communications》1988,65(1):95-108
It is shown in this paper how to interpolate a required excess Gibbs free energy-composition isotherm between two such given isotherms.
Efectively, our procedure employs semi-empirical equations for the excess Gibbs free energy, whose adjustable parameters can be identified with infinite dilution properties, and still be made to give close fits, to experimental data. Prediction of these infinite dilution properties is achieved through the use of a linear correlation between them and certain pure component properties. Thus in addition to the two given isotherms, the input into our theory consists of the Antoine vapor pressure constants, critical constants and acentric factors for the pure components.
Our theory has been tested against experimental data for four binary systems ranging from moderately non-ideal to highly non-ideal; the agreement is very good.
The successful execution of the present program highlights the possibility of predicting (gE-x) isotherms, given limiting activity coefficients (determined chromatographically or otherwise), and a single data point for the equi-molar mixture. 相似文献
Efectively, our procedure employs semi-empirical equations for the excess Gibbs free energy, whose adjustable parameters can be identified with infinite dilution properties, and still be made to give close fits, to experimental data. Prediction of these infinite dilution properties is achieved through the use of a linear correlation between them and certain pure component properties. Thus in addition to the two given isotherms, the input into our theory consists of the Antoine vapor pressure constants, critical constants and acentric factors for the pure components.
Our theory has been tested against experimental data for four binary systems ranging from moderately non-ideal to highly non-ideal; the agreement is very good.
The successful execution of the present program highlights the possibility of predicting (gE-x) isotherms, given limiting activity coefficients (determined chromatographically or otherwise), and a single data point for the equi-molar mixture. 相似文献
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T. E. Vittal Prasad D. H. L. Prasad G. Mallikarjun Peer Ahmed Suchi Singh P. Lavanya Reddy 《Chemical Engineering Communications》2008,195(7):738-744
Bubble point temperatures at 94.95 kPa, over the entire composition range, are measured for the binary mixtures of nitrobenzene with: cyclohexane, n-hexane, n-heptane, n-decane, and o-, m-, and p-xylenes, using a Swietoslawski-type ebulliometer. Liquid phase composition versus bubble point temperature measurements are well represented by the Wilson model. Computed values of the excess Gibbs energy are presented and discussed. 相似文献
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T. E. Vittal Prasad G. Mallikarjun Peer Ahmed Suchi Singh P. Lavanya Reddy 《Chemical Engineering Communications》2013,200(7):738-744
Bubble point temperatures at 94.95 kPa, over the entire composition range, are measured for the binary mixtures of nitrobenzene with: cyclohexane, n-hexane, n-heptane, n-decane, and o-, m-, and p-xylenes, using a Swietoslawski-type ebulliometer. Liquid phase composition versus bubble point temperature measurements are well represented by the Wilson model. Computed values of the excess Gibbs energy are presented and discussed. 相似文献
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本文基于孔模型,从膜对NaCl溶液的透过实验中,得到8种膜的结构参数,实验结果表明,从溶质透过膜的参数与从溶剂透过膜的参数得到的膜结构参并不一致。 相似文献
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煤气化用煤粉需要控制煤粉粒度。选择与确定了激光粒度法测定煤粉粒度的最佳条件,以水、醇为分散介质,乙醇作分散剂,高速流动进样,对采样持续时间、采样开始时间、采样间隔时间等进行验证,结果表明本方法操作简单,分析速度快,重复性好,可满足煤粉粒度测定要求。 相似文献
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根据文献[1]的斜率公式,本文提出了用一端的无限稀释活度系数去推算另一端的无限稀释活度系数的新方法。共推算了60个体系,获得了较为满意的结果,总推算平均相对误差为7.46%。 相似文献
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介绍了自行研制的高温高压振动丝黏度密度仪的构造和测定原理,并以正戊烷作为实验流体对仪器的可靠性和准确性进行了测试.测定了环己烷在323.15~413.15 K温度范围内、正辛烷在313.15~393.15 K温度范围内、苯在303.15~445.15 K温度范围内压力分别为常压和6.10 MPa、正庚烷和异辛烷在298.15~403.15 K温度范围内压力分别为常压和5.10 MPa下的黏度与密度,并分别对不同压力下的黏度、密度数据进行了关联. 相似文献
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Diffusion coefficients for He—(CH4, C2H6, C3H8, and n-C4H10) mixtures of gases at 23°C and 100°C, and at 2.1 atm were measured using an arrested-flow chromatographic method after Knox and McLaren (1963). By this procedure the flow of a band of solute gas in a carrier gas (He) is stopped when the band reaches the midregion of the column. The band spreads by diffusion during the period of arrested flow, and is then eluted by resuming the flow. The band variance at the column exit varies with the time of arrested flow such that the slope is proportional to the diffusion coefficient. The method appears to be an accurate and accessible method to measure binary diffusion coefficients. 相似文献
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