正丙醇黏度方程研究

正丙醇被广泛应用于化工、医药和农业等领域,可靠的热物性数据是理论研究和工程应用的基础。黏度作为流体重要的热物理性质之一,在生产流程的设计与优化和产品质量监测等方面具有重要意义。通过实验测量得到的黏度数据一般离散分布于不同的热力学状态,在工程中难以直接应用,因此,建立可靠的黏度方程以实现任意状态黏度的计算非常必要。经文献调研发现,目前缺少宽范围、高精度的正丙醇黏度方程,基于国内外已发表的实验数据开发了正丙醇高精度黏度方程。该方程不仅能够很好地复现实验数据,而且具有合理的外推性,其温度适用范围为150~400 K,压力适用范围为0.1~120 MPa,方程在计算范围内估计不确定度为1%~5%。     

标准氢的黏度方程

在广泛搜集标准氢（25%仲氢）黏度实验数据的基础上,运用单纯形算法拟合了标准氢的黏度计算方程,方程计算值与实验数据的偏差一般在2.0%以内。方程的适用范围为温度100～500 K,压力不超过200 MPa的区域。方程的不确定度为2.0%。方程具有一定的外推性,可以用于标准氢三相点温度到100 K以及500～1000 K,压力不超过500 MPa的区域;100 K以下,除临界区和气相区,方程的不确定度为3.0%,500 K相似文献   

基于PR方程的碳酸二甲酯摩擦理论黏度模型

在对文献中发表的碳酸二甲酯黏度实验数据进行全面收集的基础上,将摩擦理论与工程上常用的Peng-Rob inson状态方程(PR方程)结合建立了碳酸二甲酯的液相黏度模型,通过最小二乘法回归得到了模型中的各系数。结果表明:在拟合范围内,碳酸二甲酯黏度模型的计算值与实验数据绝对平均偏差和最大偏差分别为1.78%和6.34%。所建立的黏度模型适用的温度范围为283—383 K,压力范围为饱和压力接近于100 MPa,文章为碳酸二甲酯作为替代燃料等的进一步深入研究和工程应用提供了黏度计算模型。     

氯化钙－正丙醇－水溶液稀释热

使用ＬＫＢ－２１０７型流动式微量热计测量了２８８．１５Ｋ，２９８．１５Ｋ和３０８．１５Ｋ下ＣａＣｌ_２－ｎ－Ｃ_３Ｈ_７ＯＨ－Ｈ_２Ｏ溶液的稀释热。混合溶剂中正丙醇摩尔分数Ｘα：０．００，０．１３，０．２５，０．５０，０．７５，０．８７和１．００。测量结果用扩展的Ｄｅｂｙｅ－Ｈｕｃｋｅｌ方程关联，计算了不同溶剂组成下溶液无限稀释热△Ｈ_Ｄ（ｍ＝０．５，Ｘα）。结果表明：Ｘα相同时，－△Ｈ_Ｄ随温度增加而增加；温度相同时，随Ｘα变化，当Ｘα≈０．８７时，－△Ｈ_Ｄ具最大值。     

丙酮-正丙醇体系汽液平衡的研究

本文用改进的Dvorak—Boublik汽液平衡釜,测定了丙酮-正丙醇二元体系在30℃、35℃和40℃的三组怛温数据,还测定了在760mmHg压力下的一组恒压数据。上述数据用三参数RK方程、二参数Wilson方程和UNIQUAC方程进行关联,关联结果与所测定的平衡数据进行对比,获得了满意的结果。     

正丙醇脱煤中有机硫的研究

对重庆市涪陵高硫煤在正丙醇溶剂中的脱有机硫规律进行了研究．采用单因子法考察了粒径、煤浆溶剂体积与煤样质量比、时间及温度等因素对脱硫的影响,优选出正丙醇脱除原煤中有机硫的最佳条件为：煤粒粒径100目～120目,煤浆溶剂体积与煤样质量比为16,反应时间为90min,反应温度为30℃,在最佳条件下,测得煤样的有机硫脱除率在42．82％～60.70%之间。     

桑枝多糖黏度特性的研究

采用布氏黏度计对桑枝多糖的黏度进行测定,分别考察温度、剪切速率以及pH值对桑枝多糖黏度的影响,结果表明:桑枝多糖溶液为假塑性流体,随着温度的升高其黏度逐渐降低且两者的关系符合阿累尼乌斯模型,温度和浓度对其黏度的综合影响可用数学模型η=-5.924 5exp 2.48/RT-0.123 8C+3.421×10-4C2)进行预测,适用范围温度20~80℃,浓度1%~8%;剪切速率对其黏度的影响可用幂律模型η=Mγn进行拟合,黏度随剪切速率的增加而降低,酸和碱均使桑枝多糖溶液黏度下降,中性条件下黏度值最高,说明桑枝多糖是中性多糖.     

氟化钠在正丙醇水溶液中的溶解焓

利用带恒温外壳的高灵敏度密闭式量热计,测量了298.15K下氟化钠在不同组成的正丙醇 水中的溶解焓,溶剂中正丙醇含量是2.5,5.0,7.0,10.0,12.0,15.0,24.4,39.9mol％。电解质氟化钠浓度是0.009～0.043m。在测量结果的基础上,利用德拜-尤格尔第二极限公式,计算了氟化钠在无限稀释溶液中溶解焓。     

正丙醇脲醛树脂的合成

本文论述了丙醇脲醛树脂的合成,并对合成条件进行了探讨,采用本法制备的产品,效果好、贮存稳定。     

Solubility profiles of poly(ethylene glycol)/solvent systems. II. comparison of thermodynamic parameters from viscosity measurements

Solution thermodynamics of PEG samples in aqueous and nonaqueous (methanol, chloroform, tetrahydrofuran, and dimethylsulfoxide) solutions have been investigated by viscometric studies at 25, 30, 35, and 40°C. The hydrodynamic expansion factor, a_h, and the unperturbed root mean square end‐to‐end distance, , found for the system indicated that the polymer coils contract as the temperature is raised. The long‐range interaction parameter, B, was also evaluated and a significant decrease with increasing temperature was observed. The theta temperatures, θ, obtained from the temperature dependence of (1/2 ? χ) and the second virial coefficient, A₂, are quite good in agreement with the calculated values evaluated via extrapolation and interpolation methods. The thermodynamic interaction parameter, χ, was evaluated through the sum of the individual values of enthalpy and entropy dilution parameters for PEG samples. The restrictions applying to the establishment of concentration regimes, short‐range, and long‐range interactions are discussed. A parallelism is found between solubility profiles obtained by solution viscometry and solubility parameter approaches for PEG/solvent systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

丙醛常压气相催化加氢制正丙醇催化剂的研究

采用浸渍法制备一系列Cu催化剂,在固定床小粒度连续流动反应器中评价了Cu催化剂的催化性能。主要考察了Cu、Zn等含量和反应条件对丙醛催化加氢制备正丙醇反应的影响。实验结果表明,Cu、Zn等含量对该反应有明显的影响;催化剂适宜组分(m%)为:催化剂中含铜8.0%～12.0%、锌10.0%、Na2O 0.8%～1.0%,竞争吸附剂选择a;得出了适宜的反应条件:氢/醛物质的量比为10.0、温度100～130℃、反应压力0.05～0.10 MPa,原料液体空速:0.1～0.3 h-1;在该反应条件下,丙醛转化率≥99.0%,正丙醇选择性大于99.0%。     

Correlation and prediction of the viscosity of pure hydrocarbons

A relationship is identified between the effective carbon number (ECN) and parameter b in the one-parameter viscosity euation: log (μ + 0.8) = 100 (0.0lT)^b. The generalized correlation, b = -5.745 + 0.616 In (ECN) - 40.468 (ECN)^?15, provides an equation to predict parameter b, which gives values that are within the maximum deviation of 5% for ECN < 10 and 1% for 10 < ECN < 44 of the empirically-determined values for 70 liquid hydrocarbons. The calculated viscosities are within 5% of literature data. The viscosity prediction method is simple to use, and it can be extrapolated reliably to heavier hydrocarbons.     

Correlation of bitumen viscosity with temperature and pressure

A previous viscosity-temperature correlation (Puttagunta et al., 1992) is extended to include a pressure term and employed successfully in predicting the combined effect of temperature and pressure on the viscosity of Canadian bitumens and heavy oils. Predictions are made on new sets of data based on a single measurement of viscosity at 30°C and 101.3 kPa pressure; and the results show similar accuracy as obtained in the sets of data used in developing the correlation. The correlation yields an absolute average deviation between predicted and experimental viscosity of 4.79% and a correlation coefficient of 0.99 over a range of temperatures between 20 and 120°C and gauge pressures between 0 and 18 MPa.     

Correlation and prediction of the viscosity of defined and undefined hydrocarbon liquids

A new method based on the effective carbon number is presented for the correlation and prediction of the viscosity of liquid hydrocarbons and hydrocarbon mixtures. It is proposed that the effective carbon number for the substance of interest be obtained from a single viscosity datum in the liquid range. The viscosity-temperature relationships of sixty-nine hydrocarbons, eleven defined hydrocarbon mixtures and eight crude oil fractions were studied in the present work. In general, calculated viscosities compared favorably with experimental data for all the systems studied. The calculated viscosities were also found to compare favorably with the results of the widely-used TRAPP method.     

用局部组成理论关联纳米流体的剪切黏度

In this study, a new method is presented to correlate the shear viscosity of nanofluids by local composition theory. The Eyring theory and nonrandom two-liquid (NRTL) equation are used for this purpose. The effects of temperature and particle volume concentration on the viscosity are investigated. The adjustable parameters of NRTL equation are obtained by fitting with experimental data. The calculated shear viscosities for nanofluids of CuO/water with 29 nm particle size, Al2O3/water with two different particle diameters, 36 nm and 47 nm, and CuO/(ethylene glycol, water) are compared with experimental data and the average absolute deviation (AAD) is 1.2%, while the results from some conventional models yield an AAD of 190%. The results of this study are in excellent agreement with experimental data.     

凝胶型连结料体系黏度模型的参数拟合

采用有机铝型螯合物凝胶剂、松香改性酚醛树脂、亚麻仁油和高沸点煤油制备胶印油墨用连结料,研究了亚麻仁油、高沸点煤油和凝胶剂的用量对连结料流变性能的影响。根据流变实验测定值,准确地拟合出该连结料体系的一系列黏度模型。根据该黏度模型,能够在改变原料配比、温度与剪切速率的条件下,相当精确地描述连结料体系的黏度。因此,若能利用汇编语言设计出连结料的配方计算软件,则可根据连结料体系中各因素变化来直接调节连结料的流变参数,达到快速调整连结料配方、缩短生产工艺时间、稳定连结料质量、适应高速印刷油墨要求的目的。     

Determination of intrinsic viscosity of polyelectrolyte solutions

Intramolecular hydrodynamic contribution η_intra/C to the reduced viscosity η_SP/C of polyelectrolyte solutions is derived as a function of polymer concentration C by separating the theoretically calculated intermolecular electrostatic contribution η_inter/C from the observed reduced viscosity, assuming an additivity, η_SP/C=η_intra/C+η_inter/C. The resulting intramolecular part η_intra/C reflects nearly the net effect of the polyion conformation; it increases monotonously with decreasing polymer concentration and levels off to a constant in sufficiently dilute concentrations. The leveling-off value of η_intra/C corresponds to the intrinsic viscosity [η]. From the estimated values of [η], the ionic strength I dependence of the polyion conformation has been visualized, resulting in a similarity between two relations, η_intra/C vs. C and [η] vs. I.     

Dimensionally invariant viscosity function

The use of classical dimensional analysis in viscosity modelling is discussed. The method suggests relations between model parameters and molecular characteristics of a polymeric system.