Viscosity of cold lake bitumen and its fractions

New data are presented for the effect of temperature on the viscosity of bitumen fractions, which were obtained by vacuum distillation of a large Cold Lake bitumen sample. The viscosity of these fractions differs by several orders of magnitude; from 4.3 mPa?s for Cut 1 to 430 000 mPa?s for Cut 4 at 30°C. Cut 5 is a glass-like solid at room temperature with a softening temperature of about 100°C, and has a viscosity of 800 000 mPa?s at 120°C. The effect of temperature on the viscosity of each bitumen fraction is modelled very well with a two-parameter correlation that was shown to be valid generally for Alberta bitumens. The results of bitumen viscosity calculations, based on a simple liquid-mixture viscosity formula, are presented and compared with the bitumen viscosity data.     

Properties of cold lake bitumen saturated with pure gases and gas mixtures

This paper presents new data for the viscosity, density and gas solubility of Cold Lake bitumen saturated with light gases and gas mixtures over a temperature range of 15 to 103°C at up to 10 MPa pressure. Specifically, the gases whose effects on the bitumen properties were measured are N₂, CH₄, CO₂ and C₂H₆, and two mixtures of CO₂ and CH₄. With CO₂ and C₂H₆, experiments were also performed in the liquid-liquid region, and the results of these experiments generally agree with the previously published predictions. The viscosity of the gas-free Cold Lake bitumen is comparable to that of a Marguerite Lake bitumen that was tested previously. Due to the large solubilities of C0₂ and C₂H₆, the reduction in gas-saturated bitumen viscosity is quite dramatic. The density of the gas-saturated bitumen decreases with increased amounts of the dissolved CH₄ and C₂H₆ gases, but no such trends are evident for the N₂ and CO₂ gases. The results of the experiments with two binary gas mixtures (i.e., CO₂ and CH₄) indicate that the bitumen properties are affected largely by the major gas constituent.     

Correlation and prediction of gas solubility in cold lake bitumen

The solubility data for pure light gases, namely N₂, CH₄, CO₂ and C₂H₆, in Cold Lake bitumen are correlated by use of the Peng-Robinson equation of state. Modeling Cold Lake bitumen as a mixture of three pseudocomponents adequately matched two sets of the gas-solubility data. The critical properties and acentric factor for the bitumen pseudocomponents were estimated using the Kesler-Lee correlations. For each gas-bitumen pair, a single constant value of the binary interaction parameter is shown to predict the gas-solubility data with average deviations ranging from 2 to 8%. Subsequently, these calculations were extended to predict the solubility of CO₂+CH₄ gas-mixtures in Cold Lake bitumen. It is shown that the solubility predictions for the gas mixtures data are higher by approximately 6 to 9%.     

Measurement of asphaltene agglomeration from cold lake bitumen diluted with n-alkanes

A laser particle analyzer was used to study the formation of asphaltene agglomerates from Cold Lake bitumen due to the introduction of paraffinic diluents. The growth of the particles over time was investigated, and it was found that asphaltene particle growth is essentially an instantaneous process; that is, the final agglomerate size is reached within 5 seconds. The type of diluent used to precipitate the asphaltenes was determined to have a major effect on the size distribution of asphaltene agglomerates. The average particle size of asphaltene agglomerates ranged from 169 ptn for n-hexadecane to 299m for n-pentane. A relationship is shown to exist between the average particle size of asphaltene agglomerates and the carbon number of the diluent used.     

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.     

Viscous characteristics of a Utah tar sand bitumen

The viscous behaviour of an extracted tar sand bitumen has been experimentally examined and the results summarized in this Paper. The material studied was from the Asphalt Ridge, Utah area. The viscosity of the bitumen has been determined as a function of temperature (293–422 K), toluene (solvent) content (0–10%), composition (0–14.6% asphaltenes), oxidation and shear history. In all cases studied, the Arrhenius plots were significantly non-linear at temperatures s> 373 K, with viscous behaviour becoming less sensitive to toluene content with increasing temperature. Low temperature behaviour was strongly dependent on toluene content. The presence of asphaltenes in the bitumen was shown to be a strong viscosity enhancer. Oxidation and shear history were also shown to measurably increase the bitumen viscosity.     

Thermo‐physical properties of n‐pentane/bitumen and n‐hexane/bitumen mixture systems

The gravity drainage as a result of viscosity reduction is the main governing mechanism of the solvent‐aided thermal bitumen recovery processes. Therefore, the density and viscosity of the diluted or heated bitumen are essential to predict the oil production rate. In this paper, we report thermo‐physical properties of n‐pentane/bitumen and n‐hexane/bitumen mixtures. The density and viscosity of Athabasca bitumen diluted with n‐pentane and n‐hexane were measured at different temperatures (30 to 190 °C), pressures (2 to 8 MPa), and solvent mass fractions (0.05 to 0.5). Various correlations and mixing rules proposed in the literature were examined to calculate the density and viscosity of the diluted bitumen. This study proposes appropriate mixing rules and generalized parameters for predicting the density and viscosity of solvent‐bitumen systems. Our findings will find applications in the design and simulation of heavy oil and bitumen solvent‐aided thermal recovery processes.     

Zncl2 catalyzed flash hydropyrolysis of +525°C pitch from cold lake bitumen

Flash hydropyrolysis experiments have been performed on the vacuum bottoms fraction of Cold Lake bitumen, using zinc chloride as a catalyst. Milligram size samples of vacuum bottoms resid were heated rapidly (120–400°C/s) by passing a large electric current through the reactor tube. The variables studied included temperature, heating rate, catalyst/pitch ratio, vapour phase residence time and pressure. Temperature and catalyst/pitch ratio caused major changes in yields. In contrast pressure had little effect. It was found that high conversions could be obtained at hydrogen pressures which are much lower than those normally used in catalytically hydrocracking residual oils.     

Diffusion coefficients of propane and butane in peace river bitumen

Diffusion plays a vital role in the “Vapex” process. In the present work the results of experiments on “Vapex” using a Hele-Shaw cell have been used to obtain empirical correlations for the diffusivities of propane and butane in Peace River bitumen. Additional data required for the estimation of diffusivities from these experiments are the solubilities of solvent in bitumen and a correlation for the viscosity of solvent bitumen mixture. Diffusivities are assumed to decline exponentially with viscosity. Computed values of diffusion coefficients fall within the range of the published data for similar systems. This simple experiment can be used to estimate the diffusivities of gaseous solvents in highly viscous fluids.     

非电解质水溶液的粘度方程

在Eyring的液体粘性流动模型基础上,根据Rother等的假定和Shealy与Sand ler的水溶液过量自由焓溶质聚集模型,导出了一个双参数非电解质水溶液的粘度模型。利用该模型可由二元水溶液的2个模型参数预测多元水溶液的粘度。用该模型计算了6个体系391个不同温度和组成的二元水溶液和3个体系164个不同温度和组成的三元水溶液的粘度,计算值与实验值的总平均相对偏差分别为1.732%和2.977%,计算值与实验数据吻合很好。     

Molecular weight distribution of Athabasca bitumen

A sample of whole Athabasca bitumen has been fractionated by preparative g.p.c. The weights of the fractions have been determined and their molecular weights measured by several methods. In contrast to previously published data, consistent results were obtained using different solvents (THF, be-nzene/water) and using different techniques (v.p.o., f.p.d. and g.c.-m.s.). This has resulted in an accurate definition of the molecular weight distribution of Athabasca bitumen.     

Determining Bitumen Viscosity Through Drop Shape Recovery

In determining the viscosity of bitumen using conventional methods, the measurements must be conducted at extremely slow shear rates to avoid dissipative heating. In this study, bitumen viscosity is measured at room temperature using a drop shape recovery technique which, as will be shown, is immune to any problem of dissipative heating. The method involves stretching a small droplet of bitumen (and in general, of any viscous liquid) with micropipettes and allowing it to recover to its original spherical shape; the dimensions of the droplet can be as small as several micrometres. The shape recovery process is driven by capillary forces and rate‐limited by the droplet viscosity. As such, knowing the interfacial tension, the droplet viscosity can be determined accurately from the relaxation dynamics. With conventional viscometers, the problem of dissipative heating often increases linearly with the viscosity and quadratically with the shear rate. This is in contrast with shape recovery experiments, where dissipative heating is independent of shear rate and varies inversely with the viscosity.     

原油黏度变化影响因素概述

从原油自身物性组成、表面活性剂（化学降粘剂）、外界物理因素三个方面论述了影响原油粘度变化的原因及作用机理,并结合油田现场实际生产工况,针对多种物理因素组合引发原油粘度异常变化进行了原因探究。     

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   

有机物水溶液粘度的关联和预测

在Eyring的液体粘性流动模型的基础上,根据Sandler的水溶液过量自由焓溶质聚集模型,导出有机物水溶液的粘度模型。利用该模型方程参数与温度的关系,可预测低压下各种温度和不同组成的有机物水溶液的粘度。用该模型计算了7个体系442个不同温度和组成的二元水溶液和3个体系164个不同温度和组成的三元水溶液的粘度,计算值与实验值的总平均相对偏差分别为1.554%和2.588%,计算值与实验数据吻合很好。     

Oxidation reaction kinetics of Athabasca bitumen

The oxidation reaction kinetics of bitumen from Athabasca oil sands have been investigated in a flow-through fixed bed reactor using gas mixtures of various compositions. The system was modelled as an isothermal integral plug-flow reactor. The oxidation of bitumen was found to be first order with respect to oxygen concentration. Two models were examined to describe the kinetics of bitumen oxidation. In the first, the Athabasca bitumen is considered to be a single reactant and the oxidation reaction a single irreversible reaction. The activation energy for the overall reaction was found to be 80 kJ mol^?1. This model is limited to calculating the overall conversion of oxygen. Because the fraction of oxygen reacting to form carbon monoxide and carbon dioxide increases with temperature, a more sophisticated model was proposed to take this into account. The second model assumes that the bitumen is a single reactant and that the oxidation of bitumen may be described by two simultaneous, parallel reactions, one producing oxygenated hydrocarbons and water, the other producing CO and CO₂. The activation energy for the first reaction was found to be 67 kJ mol^?1, and for the second, 145 kJ mol^?1. This more sophisticated model explains the result that at higher temperatures more oxygen is consumed in the oxidation of carbon, because this reaction has a higher activation energy than the reaction leading to the production of oxygenated hydrocarbons and water. This model can also predict the composition of the product gases at various reaction conditions.     

液体非电解质水溶液粘度的关联

在Teju-Rice液体混合物模型的基础上,对常用的液体混合物粘度关联式进行了分析和比较,导出了适用于二元和多元水溶液的粘度模型。用该模型计算了6个体系388个不同温度和组成的三元水溶液的粘度,计算值对文献实验数据的总平均相对偏差分别为6.09%和5.54%,计算值准确性优于Teju-Rice模型。     

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.     

Polymer‐modified bitumen of recycled LDPE and maleated bitumen

Maleated bitumen was prepared by the reaction of penetration grade bitumen (80/100) with maleic anhydride at 150°C for 2 h under nitrogen atmosphere. The effectiveness of maleation was assessed in bitumen–recycled low‐density polyethylene (LDPE) blends in terms of their softening point and elastic recovery. It was observed that the softening point and elastic recovery of the blends increased after maleation of the base bitumen owing to the formation of an asphaltene‐linked‐LDPE system. To obtain the desired elasticity, a recoverable composition was worked out with the help of maleated bitumen, recycled LDPE and styrene–butadiene–styrene. The storage stability of the blends was assessed in terms of their difference in softening points, rheological parameters, and microstructure of the top and bottom portions of test tube samples. The difference in softening point of the recoverable maleated bitumen blend was 5°C as compared to 60°C for the base bitumen blend. The phase angle was also reduced to 7.4° at 70°C compared with the 44.30° for the base bitumen blend. Scanning electron micrographs indicate that polymers existed in both the top and the bottom portions of the aged test tube maleated blend samples. The stability of the blend was further improved when LDPE is colloidal milled with maleic anhydride in the blend preparation. Roofing bitumen was also made with maleated bitumen containing 9 wt % recycled LDPE content. Based on the rheological data, it was found that the maleated bitumen–LDPE blend exhibited superior time‐/temperature‐dependent response and higher creep recovery compared with the base bitumen blend. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013