聚合物溶液流变曲线及粘温特性研究

用长庆油田北三区处理后清水、聚丙烯酰胺配制了聚合物母液和目的液,聚合物母液浓度5000mg/L、目的液浓度2000mg/L,测量温度为10~60℃,剪切速率为1~100s~(-1),考察了剪切速率、温度对不同浓度聚合物的流变性、粘度影响。结果表明,聚合物溶液的粘度随剪切速率的增大不断降低,同一剪切速率下聚合物溶液的表观粘度随温度的升高也有所下降,随着测量温度的升高,聚合物溶液的屈服应力逐渐降低,稠度系数K逐渐增大而流变行为指数逐渐减小,在实际测量温度范围内,聚合物溶液属于非牛顿流体,体现出典型的屈服-假塑性流体特性,剪切速率对聚合物溶液的粘度值影响很大,测量温度对粘度值的影响较小。     

柴油低温流动改进剂的研究现状

综述了柴油低温流动性能改进剂(DFI)的国内外发展历史及现状,分析了DFI的降凝机理,介绍了DFI的种类,讨论了DFI的感受性,提出了DFI的发展建议.     

柴油低温流动性改进剂

介绍了柴油低温流动性改进剂的种类、应用情况、作用机理、感受性和评价方法。     

柴油低温流动性改进剂

介绍了柴油低温流动性改进剂的种类、应用情况、作用机理、感受性和评价方法。     

柴油低温流动改进剂AMMSV的制备与性能研究

选择了丙烯酰胺、α-甲基丙烯酸高碳醇酯、马来酸酐、醋酸乙烯酯、苯乙烯等为单体,在一定条件下进行聚合,得到五元聚合物AMMSV,考察其对柴油低温流能的影响。实验表明,它对柴油的凝固点和冷滤点具有明显的降低作用,且随AAMVS加入量增加,低温改进效果进一步提高,当其加入量为0.12%时,可降低吐哈-20#柴油的凝固点达15℃,降低冷滤点达6℃。     

曙光特稠油粘温特性及流变特性实验研究

为了给超稠油输送管道优化运行及节能技术研究奠定基础,对辽河油田曙光特稠油进行了粘温特性及流变特性研究,回归出了曙光特稠油粘温方程,对比分析结果表明回归公式的计算值与实测值误差很小;得到了各测试温度下的流变方程和流变曲线,并得出结论,当温度高于75℃时,可将超稠油视为牛顿流体。     

生物柴油低温流动改进剂复配研究

采用碱催化法制备菜籽油生物柴油和棕榈油生物柴油,对其主要品质指标进行分析;考察了添加不同的柴油低温流动改进剂及其复配物对生物柴油低温流动性能的影响。结果表明,柴油低温流动改进剂能够改善生物柴油低温流动性能;将其进行复配后,能表现出协同效应,取得更好的降滤效果,尤其能使饱和脂肪酸甲酯含量高的棕榈油生物柴油冷滤点降低8℃;不同生物柴油对柴油低温流动改进剂或其复配物感受性存在较大差异,不饱和脂肪酸甲酯含量高,且脂肪酸甲酯种类较多、分布较广的菜籽油生物柴油对单一低温流动改进剂感受性好,而饱和脂肪酸甲酯含量高,且脂肪酸甲酯种类分布较集中的棕榈油生物柴油对复配物感受性好。     

生物柴油低温流动性能的研究

生物柴油是典型的绿色能源,主要成分是脂肪酸甲酯。生物柴油的低温流动性与饱和脂肪酸甲酯的含量及分布有关,还与脂肪酸酯支链程度有关。综述了改善生物柴油低温流动性的方法,分析了降凝剂对生物柴油的降凝机理以及今后的研究方向。     

锡14块特超稠油流变性实验研究

稠油流变性特征对稠油开采、数值模拟、集输工艺等均是有重要的参考作用,用旋转粘度法研究了中原油田锡14块原油的粘-温特性和流变特性。结果表明：温度越低,该区块稠油粘度对温度变化越敏感,原油的粘-温拐点为70℃,油藏温度下屈服值达到61.3 Pa,原油的牛顿流体转化温度在85～90℃以上;含乳化水30%左右时,在50～90℃温度范围内乳化水对原油粘度有较大影响。     

生物柴油低温流动性改进方法研究综述

综述了生物柴油低温流动性的主要影响因素,改进方法及基本原理等相关研究进展。着重介绍了生物柴油的低温流动性的改进方法,包括冷滤法、添加剂法、产品调和法以及一些其他方法。最后对低温流动性改进方法进行了展望。     

The effect of temperature and pressure on the physicochemical properties of petroleum diesel oil and biodiesel fuel

Three commercial fuels were studied: biodiesel (based mainly of the fatty acids methyl esters of rapeseed oil), diesel oil Ekodiesel Ultra (standard petroleum diesel oil with sulphur content less than 10 mg/kg), and ON BIO 10 (blend of 20 vol.% of biodiesel with 80 vol.% of standard petroleum diesel oil with sulphur content less than 10 mg/kg). The speeds of sound were measured within the temperatures from 293 to 318 K and at pressures from 0.1 to 101 MPa. The densities and heat capacities were measured under atmospheric pressure in the temperature range from 273 to 363 K and 283 to 359 K, respectively. Using the experimental results, the physicochemical properties such as: density, isentropic bulk modulus, heat capacity, and isobaric thermal expansion were calculated in the same temperature and pressure range as the speed of sound was measured. The results obtained show that although the bulk modulus of ON BIO 10 is higher than that of diesel oil Ekodiesel Ultra over the whole pressure range, the difference is rather small and can be compensated by temperature. Isobaric thermal expansivity of biodiesel decreases with pressure slightly less than that of the diesel oil Ekodiesel Ultra. It is approximately independent of temperature and composition of the fuel at pressures 40 ± 5 MPa.     

Low temperature exhaust gas fuel reforming of diesel fuel

The application of exhaust gas assisted fuel reforming in diesel engines has been investigated. The process involves hydrogen generation by direct catalytic interaction of diesel fuel with engine exhaust gas. Using a laboratory reforming mini reactor incorporated in the exhaust system of a diesel engine, up to 16% hydrogen in the reactor product gas was achieved at a reactor inlet temperature of 290 °C. The results showed that such levels of hydrogen can be produced with appropriate control of the reaction parameters at temperatures typical of exhaust gas temperatures of diesel engines operating at part load without any requirement for external heat source or air and steam supply. The use of simulated reformed fuel was shown to be beneficial in terms of engine exhaust emissions and resulted in reduction of NO_X and smoke emissions.     

The effect of hot surface temperature on diesel fuel deposit formation

The aim of this study is to investigate fuel deposits by using the hot surface deposition test (HSDT). In this test, diesel fuel droplets were repeatedly impinged to the hot surface and deposits were developed on it. The hot surface temperature affected the deposit formation. Different hot surface temperature showed different droplet-surface interaction, evaporation lifetime and wet/dry condition where various deposit development features resulted. The hot surface temperatures that located near MEP (maximum evaporation rate point) temperature have potential to reduce the deposit formation on the hot surface. The deposition within nucleate heat transfer boiling regime (lower than the MEP temperature) caused greater deposit accumulation on the hot surface compared to the deposition within transition heat transfer boiling regime (near the MEP temperature). Less total amount of deposit that was described as slow deposit development, resulted under non-overlapping impingement and dry deposit condition. Under the overlapping impingement and wet deposit condition, it caused the accumulation of greater total amount of deposit compared to the non-overlapping and dry deposit condition.     

The kinematic viscosity of biodiesel and its blends with diesel fuel

As the use of biodiesel becomes more wide-spread, engine manufacturers have expressed concern about biodiesel’s higher viscosity. In particular, they are concerned that biodiesel may exhibit different viscosity-temperature characteristics that could result in higher fuel injection pressures at low engine operating temperatures. This study presents data for the kinematic viscosity of biodiesel and its blends with No. 1 and No. 2 diesel fuels at 75, 50, and 20% biodiesel, from close to their melting point to 100°C. The results indicate that while their viscosity is higher, biodiesel and its blends demonstrate temperature-dependent behavior similar to that of No. 1 and No. 2 diesel fuels. Equations of the same general form are shown to correlate viscosity data for both biodiesel and diesel fuel, and for their blends. A blending equation is presented that allows the kinematic viscosity to be calculated as a function of the biodiesel fraction.     

氯磺化聚乙烯流变性能研究

研究氯磺化聚乙烯(CSM)的流变性能，特别是剪切速率、剪切应力和温度对CSM熔体表观粘度的影响。试验结果表明，CSM熔体在试验温度范围内为假塑性流体，随温度的升高其非牛顿性减弱；CSM熔体的表观粘度随表观剪切速率和剪切应力的增大以及温度的升高而降低；剪切应力对CSM的粘流活化能影响不大。     

Physical and chemical properties of ethanol-diesel fuel blends

This paper discusses the physical-chemical properties of ethanol-diesel fuel blends. The attention is focused on the properties which influence the injection and engine characteristics significantly. Main properties have been investigated experimentally. The analysis of experimentally obtained fuel properties of tested fuels and their influence on engine characteristics are presented. Physical and chemical properties of diesel fuel and ethanol-diesel fuel blends were measured according to requirements and test methods for diesel fuel (EN590, 2003). The tested fuels were neat mineral diesel fuel (D100), 5% (v/v) ethanol/diesel fuel blend (E05D95), 10% (v/v) ethanol-diesel fuel blend (E10D90) and 15% (v/v) ethanol-diesel fuel blend (E15D85). It has been proved that, for ethanol-diesel fuel blends, some additives are necessary to keep stability under low temperature conditions. Also, cold weather properties test, such as cloud point and pour point tests are negatively affected by phase separation. The rest of the properties, excepting flash point, were within diesel fuel standard specifications. Based on this study, it can be concluded that using additives to avoid phase separation and to raise flash point, blends of diesel fuel with ethanol up to 15% can be used to fuel diesel engines if engine performance tests corroborate it.     

Spectral properties of diesel fuel droplets

Absorption spectra of several types of diesel fuel are studied experimentally. Index of refraction of these fuels is calculated using subtractive Kramers-Krönig analysis. The ageing process of fuels is simulated by prolonged boiling. Radiative properties of diesel fuel droplets are calculated using the Mie theory and a simplified approach, based on approximations of absorption and scattering efficiency factors. It is pointed out that the accuracy of the simplified approach is sufficient for practical applications in the visible and infrared ranges, for various types of diesel fuel, and for droplet radii in the range from 5 to 50 μm. The monodisperse approximation is shown to be applicable for the analysis of infrared radiative properties of realistic polydisperse diesel fuel sprays.     

柴油低温流动性能研究进展

从结晶角度出发对柴油低温性能方面的研究进展进行了综述,包括X射线衍射法、光学显微技术、热力学研究、热分析技术和分子模拟技术等测试技术的应用。利用光学显微技术和热分析技术研究了柴油的低温流动性能。     

Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

The effects of the molecular aggregation structure on the rheological properties of thermoplastic polyurethane (TPU) were investigated. The TPU was composed of poly{(tetramethylene adipate)-co-(hexamethylene adipate)} glycol as the soft segments, 4,4′-diphenylmethane diisocyanate and 1,4-butanediol as the hard segments. The TPU sheets prepared by injection molding were annealed at various temperatures from 23 to 120 °C to vary the molecular aggregation structure. Glass transition temperature of the soft segment and melting points of the hard segment domains of the TPUs decreased and increased, respectively, with increasing annealing temperature. The results of DSC, solid-state NMR spectroscopy and dynamic viscoelastic measurements revealed that the degree of micro-phase separation of the TPUs becomes stronger with increasing annealing temperature due to the progress of formation of well-organized hard segment domains. The dynamic temperature sweep experiments for molten TPUs revealed that the temperature at critical gel point, which is defined as the temperature at which the dynamic storage modulus coincides with the loss storage modulus, in the cooling process increased with the progress of aggregation of the hard segments in the TPUs observed in the solid state. The uniaxial elongational viscosity measurements showed that TPUs exhibited an obvious strain hardening behavior with strain rate owing to residual hard segment domains at an operating temperature. It was revealed that the formation of well-organized hard segment domains had a profound effect on the rheological properties of TPUs, in particular on their elongational viscosity.     

Influence of organo-montomorillonite on mechanical and rheological properties of polyamide nanocomposites

The effect of organically modified montmorillonite (OMMT) on polyamide nanocomposites was studied. OMMT/polyamide nanocomposites were prepared through direct melt compounding on a conventional twin screw extruder. With increasing the loading of OMMT, the Young modulus, elongation at break and tensile strength increased. 1 mass% loading of OMMT/polyamide resulted in 11% increase of the elongation at break compared to virgin polymer, while 4% loading showed 13%. Rheological data like torque, fusion time, viscosity and shear rate were also recorded on Brabender Plasticorder and were correlated with M = CS^a and τ = K(γ)ⁿ. The value n < 1 indicated pseudo-plastic nature of the polyamide/OMMT. The torque decreased with increased loading due to soft nature of OMMT, which acts as a lubricating agent. This improvement in mechanical properties with increase in amount of OMMT loading was also indicated by the reduction in shear viscosity and torque.