二元液体混合物非理想吸附平衡数据的预测

根据气相吸附和液相吸附的热力学一致性条件 ,从溶液理论、表面热力学出发并结合相交换模型 ,提出从气相吸附平衡数据预测二元液体混合物吸附平衡的模型 ,模型中仅含 4个未知参数 .应用该模型对二元液体吸附体系进行了预测 ,结果与实验数据相当吻合     

共聚高分子溶液的分子热力学模型

引　言共聚高分子因具有很多均聚高分子所没有的性质而受到人们的广泛关注 .但文献中发表的有关共聚高分子系统的汽液相平衡 (ＶＬＥ)数据较少 ,能够用于关联或预测的分子热力学模型也不多 .最常用的模型是基于密堆积格子模型的Ｆｌｏｒｙ -Ｈｕｇｇｉｎｓ理论及其改进模型 .近年来 ,在严格的统计力学理论基础上建立非格子的链状流体状态方程引起了人们更大的兴趣 ,并相继建立了一些具有实用价值的状态方程[1～ 5] .对于共聚高分子系统 ,Ｈｉｎｏ等人[6 ]建立了实用的状态方程 ,Ｂａｎａｓｚａｋ等人[7] 在热力学微扰理论 (ＴＰＴ1)的基础上…     

含自缔合流体混合物的分子热力学模型

缔合流体及其混合物的亥氏函数和压缩因子可表示为物理相互作用的贡献和化学缔合作用的贡献两部分之和。前者可采用作者建立的非缔合流体及其混合物的分子热力学模型;作者从分子间相互作用位能函数的粘滞球模型出发,利用统计力学方法确定了混合物中自缔合作用的贡献。模型中分子间的缔合参数完全可由纯物质性质确定,而只在混合物方阱位能参数的计算中引入可调的二元相互作用参数。对于含有一个自缔合组分的二元混合物常压和高压汽液平衡数据的关联结果令人满意。     

混合物临界区域热力学性质研究进展

对近期混合物临界区域热力学性质的研究作了综述,介绍了混合物临界点和临界区域相平衡的实验测定及关联计算,对临界区域热力学性质的研究作了讨论。     

液体混合物的过量焓热力学模型

引言在溶液现象的研究中,过量焓是一个重要的热力学量,它反映了液体混合物偏离理想溶液的程度．由于能精确地测量,故能否确切地描述这个热力学量,已成为鉴定溶液理论的重要指标．对于简单的小分子液体混合物,过量焓已可由计算机模拟、微扰理论和状态方程来预测．但对于复杂分子构成的液体混合物,特别是有化学作用的系统,上述理论尚不够成熟,通常多用溶液的化学理论来描述．这种理论最早由Dolezalek提出,后经Kretschmer、Renon、Stokes、Chen、Nagata和Heintz等人进一步发展．虽然它已能满意地描述液体混合物的过量焓,但是,迄…     

非电解质液体混合物表面张力的统计热力学模型

运用Davis模型导出一个统计热力学的表面张力模型．对22个双组分体系的表面张力作了推算和关联,总平均相对偏差分别为5.45％和1.95％.并利用关联双组分体系得到的参数值,直接推测了三组分体系的表面张力,平均相对偏差为2.21％.结果令人满意.表明该方法简单、精确,便于工程应用．     

一种非共沸循环工质与R22的性能对比实验

在制冷、热泵系统中广泛使用的循环工质R22由于具有较大的GWP值和ODP值,终将被淘汰.针对工质R22的替代研究,提出了一种非共沸混合工质R290/R600a/R123(50%/10%/40%,质量),并在热泵实验台上做了不同冷凝器或蒸发器进口水温和流量的多种工况实验及分析.通过将该工质在各工况下的实验结论与相应工况下R22的实验结论进行对比分析后,发现该物质是替代R22的优良的热泵工质.     

CALCULATION OF VAPOR-LIQUID EQUILIBRIA AND SATURATED LIQUID VOLUMES FOR WATER-AMMONIA MIXTURES

The approach of using T, at ΔZ= Z^s _vZ^{s L} = 0.5 for a balanced representation of saturated volumes (V^{s L} and V^{s Vs L}( of pure components has been extended from non-polar fluids to water and ammonia. For the mixtures of these two compounds, the average absolute percentage deviation in the calculated V ^{s L} values is less than 2% without affecting the representation of vapor-liquid equilibrium values.     

MASS TRANSFER IN A SEMIBATCH SUPERCRITICAL FLUID EXTRACTION CONTACTOR FOR LIQUID MIXTURES

The problem of mass transfer in a semibatch Supercritical Fluid Extraction contactor for liquid mixtures has been considered both theoretically and experimentally. The multicomponent mass transfer model is applied to the case of a gaseous solvent rising through the liquid to be extracted. The results obtained with this model are compared with those calculated by using a liquid-liquid extraction model recently extended to supercritical extraction contactors. A simplified model is developed and all of the models considered are tested on the basis of experimental data points. Experiments are carried out in a semi-batch pilot-size apparatus and results are presented for the systems Ethanol-Water-CO₂ at 17.0 MPa, 308 K and Isopropanol-Water-CO₂ at 10.3 MPa, 313 K. Models based on the gas-liquid extraction approach are capable of representing the concentration versus time profiles at the extractor, while the liquid-liquid approach predicts lower extraction effectiveness.     

A TRANSPORT MODEL FOR REVERSE OSMOSIS SEPARATION OF BINARY ORGANIC LIQUID MIXTURES

A set of transport equations was derived for the separation of the binary mixtures of organic solvents on the basis of the surface force-pore flow (SFPF) model. These equations enable the quantitative prediction of the membrane performance data under a given set of operating conditions together with the information on the membrane pore size, interaction forces working between the solution components and the membrane material, and the activity and the molecular radii of solution components. The usefulness of such transport equations is shown for the system ethyl alcohol-heptane-cellulose membrane and some other separation systems.     

二元溶液表面张力的群论算法

从群集统计理论出发,运用溶液表面热力学原理,推导出新的溶液表面张力方程.该方程形式简单,使用方便,参数具有直观的物理意义.通过235对各类物系的实验数据检验,表明本方程具有广泛的适用性和可靠性.     

MODELLING OF AXIALLY DISPERSED NON-ISOTHERMAL TUBULAR REACTORS FOR HYDROPROCESSING OF SOLID-LIQUID MIXTURES

A mathematical model for hydroprocessing of coal-oil slurries in non-isothermal, axially dispersed tubular reactors is developed and numerically solved, considering a five component-six reaction model representing the chemistry of the process, and, dispersive, corrective and interfacial mass and energy transfers. Several simulation results are presented.     

混合电解质体系反渗透膜性能的预测

建立了一种混合电解质体系膜性能的预测方法。依据这种方法，只需一套膜规格化数据，即纯水渗透常数Ａ，氯化钠的渗透参数ＤＡＭ／Ｋδ和传质系数Ｋ，就可预测膜对任意混合电解质体系的分离性能，选用了６种醋酸纤维膜对４种混合体系（ＮａＣｌ－ＣａＣｌ２－Ｈ２Ｏ－，ＮａＣｌ－ＮａＮＯ３－Ｈ２Ｏ，ＫＩ－ＣａＣｌ２－Ｈ２Ｏ，ＮａＢｒ－ＭｇＣｌ２－Ｈ２Ｏ）的分离实验，验证了预测方法的正确性。     

PERFORMANCE OF FIVE EQUATIONS OF STATE FOR THE PREDICTION OF VLE AND DENSITIES OF NATURAL GAS MIXTURES IN THE DENSE PHASE REGION

This paper examines the degree of uncertainty of five Equations of State (EOS) for the prediction of densities in the dense phase region which is beyond the ranges of pressure and temperature originally specified for these equations. Predicted densities were compared with measured values for different hydrocarbon mixtures including a rich mixture. The results show that the GERG equation of state, originally specified for the range of P -8 C, outperforms all other equations in the region up to P=30 MPa and T > -8 C. In this range, its mean deviation from measured values of densities was found to be less than -0.015% and standard deviation ( ) also less than 0.015%. The AGA-8 equation, which identified several regions of pressures and temperatures with different uncertainties, also performed quite well with a mean deviation of -0.2% and less than 0.4% in the region up to P=30 MPa. The other equations showed relatively high deviation: ~2.7% for BWRS,-5.1% for PR and 2.5% for RKS. Unlike GERG and AGA-8, however, these three equations can also be used to predict the vapour-liquid-equilibrium (VLE). VLE predictions were compared with measured values for eight binary mixtures of methane (C1) and ethane (C2). It is recommended to use PR for VLE prediction, as quite good agreement between measured data and prediction by PR was demonstrated.     

用密度泛函理论研究非极性混合流体表面性质

应用密度泛函理论研究了二元非极性混合流体的表面性质.分子作为球形链处理,不同分子内的两链节相互作用以硬核Yukawa势能表示.为了避免计算中势能作用数值积分截断导致的误差,采用了合理的长程校正方法.根据微扰理论建立了流体的状态方程以计算汽液相平衡.从纯流体汽液相平衡数据回归得分子的链节作用参数ε/k、d和m_s,这些参数预测纯流体表面张力时可获得较好结果.继而引入混合参数k_ij表示不同分子链节作用情况,计算了6种非极性混合流体的汽液相平衡、表面张力、表面密度剖面.结果表明,本方法应用于二元非极性流体混合物时汽液表面张力计算值与实验值符合良好,同时显示某些二元混合流体表面区可能出现组分的相对富集现象.     

PERFORMANCE CHARACTERISTICS OF PIPE BENDS AS METERING DEVICES FOR OIL/WATER MIXTURES

The applicability of pipe bends as metering devices for two-phase oil/water emulsions was investigated. The discharge coefficients were determined for emulsions over a wide range of oil and water concentrations. At low oil concentrations, the emulsions were of oil-in-water (O/W) type. However, at high oil concentrations, the emulsions were of water-in-oil (W/O) type. The inversion point was detected by an in-line conductance cell. A sharp change in the electrical conductance occurred upon inversion of one type of emulsion to another. Three standard long radius elbows with different dimensions and radii of curvature were tested. The results indicate that the single-phase calibration curves (discharge coefficient versus velocity) can be used to predict the flow rate of two-phase oil/water mixtures provided that the mixtures are well-homogenized. There is no observable difference between the discharge coefficients of oil-in-water and water-in-oil emulsions. The measured values of the discharge coefficients for emulsions are reasonably close to the values predicted from the equations proposed in the literature for single-phase fluids.     

A MATHEMATICA PROGRAM FOR THE ACCURATE CORRELATION OF DIFFERENT THERMODYNAMIC PROPERTIES OF SATURATED PURE FLUIDS

We present a simple program written in Mathematica 8.0 that permits using a general analytical expression to accurately correlate different thermodynamic properties of a saturated pure fluid. In particular, the program permits one to obtain simple analytical expressions for the liquid density, vaporization enthalpy, surface tension, and the inverse of the isobaric heat capacity of a saturated liquid as a function of the temperature along the entire vapor-liquid coexistence curve. The general expression used is the same for all four thermodynamic properties. It takes the values at both critical and triple temperatures as referents and four or fewer adjustable coefficients for each property. The program displays the absolute and relative errors together with wide information about the error distribution. It can be therefore used as a research or a pedagogical tool.     

HYDROGEN-BONDING COMPETITION IN ENTRAINER COSOLVENT MIXTURES

In chemical separation processes such as supercritical extraction, the use of an entrainer cosolvent can dramatically improve selectivity and yield. Ideally, an cntrainer cosolvent should solvate only the desired solute, pulling it from the feed. Prospective entrainers therefore are chosen for their hydrogen bonding tendency. But not all cosolvents are effective entrainers, and an entrainer that is effective for one application may not be effective for others. The effectiveness of a cosolvent as an entrainer can be limited by competition among various hydrogen bonding species in the mixture.

In this paper, experiment and theory are presented for hydrogen bonding in entrainer cosolvent mixtures. Concentrations of monomelic and hydrogen bonded species are determined using FTIR spectroscopy and these data are modeled using the Associated Perturbed Anisotropic Chain Theory (APACT). Liquid solvents with hydrogen bonding properties similar to those of supercritical fluids are used.

Using APACT, it is shown that the equilibrium constant, derived from activities, can be written as the product of a temperature dependent term and the ratio of concentrations: K = (RT)^v Π C^vi_i. This gives a statistical mechanical basis for the empirical observation that the equilibrium constant can be calculated as the ratio of concentrations of monomeric and hydrogen bonded species.     

生物质与煤混合颗粒流化特性的实验研究

在 D1 1 5 mm× 1 0 0 0 mm有机玻璃制成的圆柱型流化床中 ,对玉米秆、稻秆、煤及其混合物的流化特性进行了实验研究 .实验结果表明 ,单一生物质颗粒不能形成良好的流化状态 ,而加入一定量煤构成生物质和煤二组分混合颗粒可以实现稳定流化 .当生物质和煤混合颗粒中生物质的质量分率小于 5 0 %时 ,可以达到很好的流化状态 ,生物质和煤二组分混合颗粒的最小流化速度随生物质质量分率的增加而减小 .     

非共沸混合工质R22/R141b高温热泵实验研究

引　言大量低品位能源如太阳能、中低温地热能等常被忽略 ,有些低品位能源直接排放不仅造成极大的浪费 ,而且会给环境带来有害热污染 ,比如工业余热 (化工厂 ,发电厂 )、机车尾气等 .目前 5 0～ 80℃范围的热能可以直接用作制冷机 (吸附 ,吸收制冷 )的驱动源或用来进行加热、干燥等 ,而 30～ 5 0℃范围的热能尚无成熟高效的利用手段 ,高温热泵是其中较为可行的技术方案之一高温热泵的开发研究一直是热泵应用领域中的一个重要分支 ,如日本的ＡｋｉｏＭｉｙａｒａ 1993年以Ｒ2 2 /Ｒ114为工质进行了实验 (冷凝器入水温度 4 0℃ ,出水温度 6 0…