色谱顶空法测组分活度系数及三元液液平衡的预测

用气相色谱顶空分析法测定了9组水-正烷烃-醇部分互溶三元系在完全互溶区3个组分的活度系数.由活度系数实测值拟合出UNIQUAC过量自由焓模型参数.再用UNIQUAC方程对部分互溶区液液平衡进行了预测.其结果与文献预测比较,均方根误差均较后者(在2.5%以下)小.同时实测了环已烷—正丁醇—水三元系的液液平衡数据,结果亦令人满意.     

不同温度DMF—正庚烷—甲苯体系液—液平衡的关联

本文对六个温度下DMF-正庚烷-甲苯体系的液-液平衡进行了等温和非等温情况下的关联。本文用NRTL、UNIQUAC等六种活度系数模型进行了关联,并提出一个修正的Wilson活度系数模型,修正了温度对活度系数的贡献。本文提出的活度系数模型能够较好地同时关联不同温度下的液-液平衡。计算误差明显小于进行温度修正后的NRTL等模型,参数也较后者为少。     

色谱顶空法测活度系数及对三元极性体系液液平衡预测

用气相色谱顶空分析法测定 18组部分互溶三元极性体系在完全互溶区的 3个组分活度系数 ,由此拟合出 U NIQU AC过量自由焓模型参数 ,再用 U NIQUAC方程预测液液平衡。这一方法曾很好地用在水-正烷烃 -醇体系。将此法拓展到含醇、酮、酯 ,醚、卤烷烃和水等多种极性组分的三元体系液液平衡的预测 ,其结果与文献的液液平衡数据比较 ,平均均方根误差 1.4 1% ,表明本法对含极性组分的体系仍然可行     

立方扰动硬链状态方程GE混合规则及其应用

扩展了立方扰动硬链(CSPHC)状态方程在天然气工业中通常遇到物质的纯组分参数, 并建立了纯组分参数的普遍化关联式; 将过量Gibbs自由能混合规则引入CSPHC状态方程, 以应用于高度非对称体系与极性体系相平衡性质计算。结合MPHC活度系数模型及Wilson 活度系数模型, 对13组二元体系的汽液平衡性质获得较满意的结果。     

用气液色谱法测定三元系中挥发组分有限浓度时活度系数的研究

本文研究了用色谱方法测定三元系中二个挥发组分在有限浓度时的活度系数,提出了实验规程及导出了用色谱数据计算活度系数的公式。测定了(1)苯-环己烷-邻苯二甲酸二壬酯(DNP)在40℃、60℃时,(2)苯-环己烷-角鲨烷(SQ)在60℃、80℃时二个体系中挥发组分(苯及环己烷)的活度系数。     

催化糠醛抽提液液平衡组成计算程序开发

用润滑油糠醛精制抽出液对催化裂化回炼油进行抽提,当回炼油组成变化或对裂化产品的质量要求发生变化时,为了确定适宜的抽提操作条件并减少实验工作量,有必要对抽提过程进行热力学模拟,通过计算来预测液液平衡组成。确定了液液平衡组成计算方法,采用UNIFAC模型计算组分活度系数,并用VB语言编制了计算程序,应用牛顿-拉斐森方法解非线性方程组。该方法具有收敛速度快、精度高等优点。分别用文献中的数据验证了其中计算活度系数的子程序和整个计算程序的可靠性。子程序的计算相对偏差为0．04％,应用程序计算来预测文献体系液液平衡组成的最大绝对偏差不超过0．02,程序的计算性能可靠,考察了以纯糠醛为溶剂液液平衡组成预测,效果很好。     

用Wilson方程计算汽相组分活度系数

Wilson方程通常用作计算液相组分活度系数。本文试图以Wilson方程计算汽相组分活度系数,初次实现用活度系数方程关联汽液平衡。文中选取在汽相存有缔合现象的羧酸水溶液进行关联计算,其结果显得比文献[1]的计算结果还要好。     

UNIFAC基团贡献法研究及应用进展

UNIFAC 基团贡献法是推箅组分活度系数应用最广泛的模型之一.介绍了UNIFAC基团贡献法的研究进展,分析了UNIFAC模型在气液平衡(气体溶解度、纯组分的蒸汽压、典型气液平衡预测)、液液平衡(液体混合物的表面张力、萃取精馏体系、聚合物溶液粘度的推算、典型液液平衡预测)、固液平衡(同分异构体的平衡体系、固体溶解度的计算)体系的应用领域及其局限性,并针对UNIFAC基团贡献法存在的问题,提出UNIFAC基团贡献法的研究方向和具体的研究内容.     

基于无限稀释活度系数模型的状态方程

发展了一种从纯物质的性质参数预测混合物汽液平衡的方法,它是以立方状态方程的过量吉布斯自由能 g~E结合型混合规则和无限稀释活度系数 MOSCED模型为基础,由MOSCED模型预测得到活度系数方程的相互作用参数,从而得到混合规则中的g~E,使得状态方程能在较大温度和压力范围内预测汽液平衡.用此法预测了含极性组分体系常压到较高压力的汽液平衡,结果良好,与UNIFAC基团贡献状态方程的结果相当.     

20 kPa下己酸+乙酸/乙酸丁酯/环己酮/ε-己内酯体系汽液平衡的测定与关联

在20 kPa下,用Rose汽液平衡釜测定己酸+乙酸、己酸+乙酸丁酯、己酸+环己酮、己酸+ε-己内酯,4个体系的二元汽液平衡数据,采用Herington面积积分法对汽液平衡数据进行热力学一致性检验,结果显示所有的实验数据均符合热力学一致性。采用NRTL和Wilson活度系数模型对4个二元实验数据进行关联,得到4个二元交互参数。将模型模拟的计算值与实验值进行比较,结果表明Wilson活度系数模型更适用于该4个组分体系的汽液平衡计算。     

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。     

Miscibility and mechanical properties of poly(ether imide)/poly(ether ether ketone)/liquid crystalline polymer ternary blends

This paper is concerned with a novel ternary blend composed of poly(ether imide) (PEI), poly(ether ether ketone) (PEEK) and a liquid crystalline polymer (LCP; HX4000, Du Pont). Different compositions were prepared by extrusion and injection moulding. Dynamic mechanical thermal analysis and the observation of the fracture surfaces, before and after annealing, allowed determination of the cold crystallization temperatures and miscibility behaviour of these systems. PEEK/PEI blends are known from previous studies to be miscible at all compositions. In this case it was observed that the PEEK/HX4000 blend was miscible up to 50 wt% HX4000 but partially miscible above this value. The PEI/HX4000 blends were found to be partially miscible in the whole concentration range. As a result, some ternary blend compositions exhibited only one phase, while others exhibited two phases. The measurement of the tensile properties showed that ternary blends with high modulus can be obtained at high LCP loadings, while compositions with high ultimate tensile strength can be obtained with high loadings of PEI or PEEK.     

New miscible blends composed of polysulfone and poly(1-vinylpyrrolidone-co-acrylonitrile) copolymers and their phase behavior

The miscibility of polysulfone, PSf, blend with poly(1-vinylpyrrolidone), PVP, and that of PSf blend with poly(1-vinylpyrrolidone-co-acrylonitrile) copolymers, P(VP-AN), containing various amount of VP were explored. Even though PSf did not formed miscible blends with PVP when both components had high molecular weight, it formed miscible blend with PVP by decreasing molecular weight of PVP. PSf also formed homogeneous mixtures with P(VP-AN) containing AN from 2 to 16 wt%. These miscible blends underwent phase separation on heating caused by LCST-type (lower critical solution temperature-type) phase behavior. The phase separation temperature of miscible blends first increases with AN content, goes through a maximum centered at about 8 wt% AN. Interaction energies of binary pairs involved in blends were evaluated from the observed phase boundaries using the lattice-fluid theory. The decline of the contact angle between water and blend film by increasing P(VP-AN) content in blend indicated that the hydrophobic properties of PSf could be improved by blending with P(VP-AN) copolymers.     

Studies on blends of polyethylene terephthalate with bisphenol-a-polycarbonate and polypropylene

Moldability and mechanical properties of polyethylene terephthalate (PET) under normal molding conditions were found to improve significantly when it was blended with bisphenol-A-polycarbonate (PC) and polypropylene (PP) to form ternary polymer blend systems. DSC results of these blends revealed that the PET and PC components formed a miscible blend while PP being incompatible with them, formed a separate phase. PP was also found to form a sleeve around the PET-PC miscible phase and, thereby, showed a skin-core type of morphology. Variations of mechanical properties with varying amounts of PP was measured keeping the ratio of PET and PC constant. Tensile and flexural properties of the blends decrease with the amount of PP. Notched impact strength increases up to a certain level of PP and then decreases, while the unnotched values decrease gradually. The effect of annealing on the mechanical properties of these blends have been discussed on the basis of the increased crystallinity of some of the components.     

气-液-固三相循环流化床中的液相轴向扩散

The effects of liquid viscosities, solid circulating rates, liquid and gas velocities and phase holdups on the axial dispersion coefficient, Dax, were investigated in a gas-liquid-solid circulating fluidized bed (GLSCFB).Liquid viscosity promotes the axial liquid backmixing when solid particles and gas bubbles are present. Increases in gas velocities and solid circulating rates lead to higher Dax. The effects of liquid velocity on Dax are associated with liquid viscosity. Compared with conventional expanded beds, the GLSCFBs hold less axial liquid dispersion,approaching ideal plug-flow reactors.     

Poly(vinylidene fluoride)–acrylic rubber partially miscible blends: Phase behavior and its effects on the mechanical properties

A phase diagram of poly(vinylidene fluoride) (PVDF) and acrylic rubber (ACM) was plotted, and the effects of the extent of miscibility on the mechanical properties of the polymer blends were examined. A compressible, regular solution model was used to forecast the phase diagram of this blend. The model prediction, the lower critical solution temperature (LCST) over the upper critical solution temperature (UCST), was done qualitatively according to the experimentally determined phase diagram by differential scanning calorimetry (DSC), optical microscopy, and rheological analysis. These experimental methods showed that this system was miscible in ACM‐rich blends (>50% ACM) and partially miscible in PVDF‐rich blends. A wide‐angle X‐ray diffraction study revealed that PVDF/ACM blends such as neat PVDF had a characteristic α‐crystalline peak. The partially miscible blends displayed up to 350% elongation at break; this was a significant increment of this parameter compared to that of neat PVDF(20%). However, the miscible blends showed elongation of up to 1000% [again, a remarkable increase compared to chemically crosslinked ACM (220%)] and displayed excellent mechanical properties and tensile strength and a large elongation at break. For the miscible and partially miscible blends, two different mechanisms were responsible for this improvement in the mechanical properties. It was suggested that in the partially miscible blends, the rubbery depletion layer between the spherulite and the conventional rubber cavitations mechanism were responsible for the increase in the elongation at break, whereas for the miscible blends, the PVDF spherulite acted as a crosslinking junction. The stretched part of the tensile samples in the partially miscible blends showed characteristic β‐crystalline peaks in the Fourier transform infrared spectra, whereas that in the miscible blends showed α‐crystalline peaks. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1247‐1258, 2013     

环氧乙烷-四氢呋喃共聚醚与硝酸酯的相溶性

研究了离子增溶剂（ＩＳＲ）对Ｐ（Ｅ－ＣＯ－Ｔ）／ＮＧ体系相溶性的影响，通过ＲＰ－ＨＰＬＣ测定了互溶相中ＮＧ含量。同时考察了在ＩＳＲ存在下，Ｐ（Ｅ－ＣＯ－Ｔ）与硝酸酯体系在室温及低温下互溶限度。通过ＦＴＩＲ分析表明，在ＩＳＲ存在下，Ｐ（Ｅ－ＣＯ－Ｔ）与硝酸酯体系由于氢键作用使其相溶性明显增加。     

乳状液膜法处理三氯乙醛废水的研究

本工作是用乳状液膜法处理三氯乙醛废水的初步实验.实验系将氢氧化钠水溶液包以煤油作为液膜,处理含有50—200ppm的三氯乙醛水溶液.实验考察了影响三氯乙醛渗透的一些因素,在适当的条件下可以脱除95%以上的三氯乙醛.并计算了该液膜体系的总包传质系数,结果表明它趋向于一个恒定值.     

Behaviour of the miscibility of poly(ethylene oxide)/liquid crystal blends

The microscopic behaviour of blends of poly(ethylene oxide) with two different low molecular weight liquid crystals (LC) was studied in order to evaluate miscibility. One of the liquid crystal components had a phase transition temperature lower than the melting temperature of poly(ethylene oxide) (PEO), and the other a higher value. The low molecular weight liquid crystal components were 4-cyano-4′-n-heptylbiphenyl (7CB) and p-cyanophenyl p-pentyloxybenzoate (pCP). Thermal analysis and polarized optical and scanning electron microscopy were employed. The melting temperature (T_m) depression of PEO increased with LC content in the blend, suggesting that the PEO was miscible with both liquid crystals in the isotropic phase. The spherulitic structural morphology of the semicrystalline components is affected by the presence of liquid crystals. © 1998 SCI.