The effect of ethoxylated nonyl phenols on the interfacial tension between crude oil and water

In this study, the effect of ethoxylated nonyl phenols with ethoxy group numbers 4 and 9 (nonyl phenol 4 and nonyl phenol 9), were investigated on the interfacial tension between crude oil and water. The interfacial tensions decreased significantly in a concentration range of 0–1.25 g.l^–1. By increasing sodium chloride concentration, the time which was required to reach equilibrium interfacial tension was reduced. Therefore, sodium chloride affected the dynamic interfacial tension. However, ethoxylated nonyl phenols resisted against change of salinity. The effect of mixed surfactants on the decreasing of the interfacial tension was more than an individual surfactant, because of the synergism. The most effective mixture of a two surfactants system was observed when mass ratio of nonyl phenol 9 and nonyl phenol 4 was 0.5.     

Dynamic Interfacial Tension Between Crude Oil and Octylmethylnaphthalene Sulfonate Solution

The surface tension of surfactant aqueous solutions and dynamic interfacial tensions (DIT) between Shengli Oilfield crude oil and solution of octyl methylnaphthalene sulfonate surfactants (OMNS) have been measured. The effects of various parameters such as surfactant concentration, salinity and sodium carbonate concentration on the interfacial behavior of crude oil-water were investigated. It was found that the prepared surfactants can reduce the interfacial tension to ultra-low only at certain surfactant concentration, salinity and alkaline concentration ranges. It was also found that there exist optimum values with respect to all of surfactant concentration, salinity and alkaline concentration. The DIT can low to 10^?6 mN.m^?1 under the optimum conditions. Moreover, the DIT behavior of OMNS flooding without alkaline has also been investigated. It was found that the DIT also reaches ultra-low value under the optimum sodium chloride concentration without alkaline. The results show that the OMNS is more effective on lowering surface tension of aqueous solutions and dynamic interfacial tensions (DIT) between crude oil and water. OMNS possesses a great potential to be used in EOR with low costs and high efficiency.     

Viscosity and conductivity measurements for dilute dispersions of rodlike paraffin particles in silicone oil

In the present article, the rheological behavior and thermal conductivity for dispersions of paraffin rods in silicone oil were investigated experimentally by examining the effects of surfactant concentration, particle volume concentration and temperature. The test suspensions at 15°C showed a strong shear-thinning viscosity as the particle concentration increased, whereas the test emulsions at 58°C showed typical Newtonian viscosity behavior. Relative viscosities of the present results agree with the theoretical results for rodlike particle suspensions. Thermal conductivities of the paraffin, silicon oil and mixture were measured with varying temperatures, respectively. Thermal conductivities of paraffin dispersions correlated satisfactorily with the Brailsford-Major equation.     

Research Interfacial Properties of the Novel Lignosulfonates

Abstract

The interfacial tensions between the crude oil and the novel modified lignosulfonate solutions were measured by a spinning drop interfacial tension apparatus. Some effects that influence on IFT were discussed. With the increase of alkyl chain length or the number of lipophilic groups introduced, the interfacial activity of the modified lignosulfonate increases, and the optimum surfactant concentration required to reach ultra-low IFT decreases. Excellent activity at the interface of crude oil and the solutions was observed. The interfacial tensions of the modified lignosulfonates could be ultra-low over a wide range of surfactant concentration and alkali concentration without the addition of other surfactants. They are capable of being the principal surfactant in enhanced oil recovery (EOR).     

Optimisation of base-catalysed transesterification of Simarouba glauca oil for biodiesel production

Biodiesel was prepared from the crude oil of Simarouba glauca by transesterification with methanol in the presence of KOH as a catalyst. The reaction parameters such as catalyst concentration, alcohol to oil molar ratio, temperature and rate of mixing were optimised for the production of Simarouba oil methyl ester. The yield of methyl esters from Simarouba oil under the optimal condition was 94–95%. Important fuel properties of methyl esters of Simarouba oil (biodiesel) was compared with ASTM and DIN EN 14214. The viscosity was found to be 4.68 Cst at 40°C and the flashpoint was 165°C.     

超稠油开发硫化氢成因分析及治理技术

辽河油田超稠油具有高密度、高黏度、高凝固点、高胶质沥青质含量的特点,其开发方式以蒸汽吞吐为主,SAGD、蒸汽驱为辅,已连续13年保持百万吨产量规模.但在开发过程中,出现了高浓度硫化氢气体,严重威胁到油区员工的身体健康,并对环境造成污染.几种开发方式中,蒸汽吞吐井硫化氢浓度相对较低,SAGD、蒸汽驱油井由于高温高压蒸汽的长期作用,硫化氢浓度较高,达到吞吐井硫化氢浓度的5倍左右.对于硫化氢成因,认为主要有两方面原因:一是超稠油中的含硫化合物在高温高压条件下发生热裂解反应,生成大量硫化氢;二是采油助剂中的磺酸盐类表面活性剂受热分解,产生少量硫化氢.针对硫化氢污染,通过引进新型表面活性剂,减少了硫化氢的释放,通过开展现场干法脱硫试验,有效处理了超稠油井伴生气中的硫化氢.     

Mathematical Relationships Derived from Biodiesel Fuels

Abstract

The objective of this study was to estimate mathematical relationships derived from biodiesel fuels from various vegetable oils by non-catalytic supercritical methanol and ethanol method. The vegetable oils are all extremely viscous with viscosities ranging from 10 to 20 times greater than petroleum diesel fuel. The aim of the transesterification process is to lower the viscosity of the oil. Methyl and ethyl esters as biodiesels were prepared from vegetable oils through transesterification by non-catalytic supercritical fluids. The biodiesels were characterized for their physical and main fuel properties including viscosity, density, flash point and higher heating value (HHV). The viscosities of biodiesels (3–5 mm²/s at 311 K) were much less than those of pure oils (27–54 mm²/s at 311 K), and their HHVs of approximately 40.5 MJ/kg were 10% less than those of petrodiesel fules (～45 MJ/kg). The most important variables affecting the ester yield during the transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. The viscosity values of vegetable oil methyl esters highly decreases after transesterification process. Compared to no. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. There is high regression between density and viscosity values vegetable oil methyl esters. The relationships between viscosity and flash point for vegetable oil methyl esters are considerably regular.     

Dynamic Interfacial Tension between Crude Oil and Dodecylmethylnaphthalene Sulfonate Surfactant Flooding Systems

Abstract

The surface tension of surfactant aqueous solutions and dynamic interfacial tensions (DIT) between crude oil, offered from Shengli Oil Field in China, and surfactant flooding systems, and the single-component dodecylmethylnaphthalene sulfonate (DMNS) surfactant, developed in our laboratory, were measured. In the present report, both buffered alkali and no alkali flooding systems were investigated. It was found that DMNS surfactant possessed great capability and efficiency of lowering the solution surface tension and the critical micelle concentration (cmc) is 0.002 mass% and the surface tension at this concentration is 29.39 mN.m^?1. It was also found that the DMNS surfactant is also greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low surfactant concentration and an optimum range of sodium chloride. The lower alkali concentration is favorable for lowering DIT. The higher alkali concentration needs a higher surfactant concentration for oil flooding systems lowering DIT. Moreover, the results indicate that there obviously exists both synergism and antagonism among the surfactant, alkali and inorganic salt. The added surfactant play an important role in reducing DIT, and the prepared DMNS surfactant possesses great capability and efficiency in lowering the interfacial tension between oil and water. The salt-modified surfactant flooding systems without alkali, decreasing the cost of oil recovery and avoiding the stratum being destroyed would have a great prospect for enhanced oil recovery.     

Use of surfactants to mitigate precipitation of nonstable asphaltensdes

In this work, we examine the effectiveness inhibition of three different surfactants (cationic, anionic, and non-ionic) with respect to aggregation of the most unstable fraction, asphaltenes, obtained from Algerian crude oil that flocculates and precipitates during oil transport and storage. Their efficacy is compared with native resins that are extracted from the same oil. We reveal from the results that the cationic surfactant didodecyl dimethyl ammonium bromide (DDAB) displayed the highest capacity to inhibit asphaltenes aggregation. This surfactant can shift considerably the aggregation onset of asphaltenes with respect to the non-ionic octylphenopoly(ethyleneglycolether)_X (TX-100) and anionic dodecyl benzene sulfonic acid (DBSA) surfactants. This finding is explained by the presence of both double alkyl chain and basic head polar (positive charge) in surfactant structure on one hand and the structural properties of studied asphaltenes (rich oxygenated negative charge sites and low aromaticity) on the other hand. Finally, the comparison between the effectiveness of native resin and the studied surfactants indicate the following order: DDAB > resin> TX-100> DBSA.     

Thermophysical properties of fly ash–Cu hybrid nanofluid for heat transfer applications

The effect of temperature and concentration on the thermophysical properties of fly ash–copper (80% fly ash and 20% Cu by volume) water-based stable hybrid nanofluid is studied. The experiments are conducted for the volume concentration range of 0 to 0.5% in the temperature range of 30 to 60°C. The nanoparticles have been characterized by transmission electron microscopy and dynamic light scattering to determine an average nanoparticle diameter of 15 nm. The stability of nanofluid in the presence of surfactant Triton X-100 is examined with the help of zeta potential. The maximum enhancement in thermal conductivity and viscosity is 19% and 22%, respectively. The outcome of the present study showed that density, thermal conductivity, and viscosity of the hybrid nanofluid increased, whereas specific heat decreased with an increase in the nanofluid concentration. In addition, the specific heat and thermal conductivity increase, there is a decrease in density and viscosity of the hybrid nanofluid with an increase in temperature.     

Efficacy of Bacillus subtilis for the biodegradation and viscosity reduction of waxy crude oil for enhanced oil recovery from mature reservoirs

Increasing maturity of the crude oil reservoirs across the world have led to the production of waxy crude oil which need economical and efficient methods for enhanced oil recovery (EOR). The studies on the performance of bacteria in the presence of waxy crude oil is rare. In this study, experiments were performed to understand the efficacy of thermophillic microorganism Bacillus subtilis on the biodegradation of waxy crude oil for EOR applications. Bacterial growth, changes in crude oil composition, viscosity reduction, and surface and emulsification activity have been monitored to evaluate the oil degradation capabilities of the bacteria. This study also presents the effect of temperature, salinity, pH, and pressure on the stability of the produced biosurfactant for EOR applications. The biosurfactant produced by bacteria in the presence of crude oil was found to be stable up to 120°C, 10 MPa, 15% salinity, and wide range of pH, and thus favorable for reservoir environment. The crude oil composition before and after degradation at 75°C was determined using gas chromatography-mass spectroscopy and observed to be 60% in one day, while the maximum viscosity reduction was found to be 60% from initial values. Experimental results showed that the bacteria used in this work are capable of surviving at reservoir conditions, and are easy to grow on the waxy crude oil for enhanced oil recovery operations.     

An experimental investigation on the effects of surfactants on the thermal performance of hybrid nanofluids in helical coil heat exchangers

In the present study, the effects of surfactants on the thermal performance of the hybrid nanofluid (Alumina–Silver) at constant wall temperature and laminar flow have been experimentally studied in a helical coil heat exchanger. Different surfactants such as anionic Sodium Dodecyl Sulfate (SDS) and nonionic Poly Vinyl Pyrrolidone (PVP) in the concentration of range of 0.1–0.4 wt.% are employed. It is found that the thermal performance can be maximized by using the 0.2 vol.% hybrid nanofluid and 0.1 wt.% SDS anionic surfactant in the helical coil. The maximum thermal performance in the presence of hybrid Alumina–Silver nanofluid and SDS anionic surfactant is 16% higher than that of the pure distilled water. The presented results can have potential application in process intensification and optimum design of heat exchangers.     

CFD investigating medium-temperature influences on performance prediction and structure stress calculation in a hydrodynamic torque converter

When computational fluid dynamics was applied in a hydrodynamic torque converter, the influences of medium temperature were always ignored. Those influences were investigated in this study. The variable viscosities and constant viscosity were carried out by a comparative study. The unsteady flow fields showed the variable viscosities results were more reasonable, whereas the constant viscosity overestimated the viscous force and leaded to inaccuracy in performance prediction. The experimental data proved that variable viscosities achieved a highly accuracy, and the performance prediction inaccuracy was 1–4%. Through the comparative analysis of the equivalent stress and deformation computed from thermal-fluid–structure interaction and fluid–structure interaction, the thermal stress from medium-temperature influence should be considered during the design of a torque converter.     

萨北过渡带和三次加密注水井增注技术的研究应用

大庆油田第三采油厂生产的石油磺酸盐阴离子型表明活性剂LD,具有表面活性强,原料来源广,质量稳定,高温不挥发、低温不结晶,常温下溶解性好,稀释配制方便等特点。为了明确LD型表面活性剂的适应性,首先在室内开展了相关实验,对表面活性剂的各项性能指标进行评价。确定了合理的注入参数,并通过现场实施4口井,取得了良好效果。实施LD型表面活性剂增注后,4口注水井累计增注21417m3,周围20口无措施采油井累计增油3663t,LD型表面活性剂对因原油物性影响的注水井有一定的增注能力,并能较好改善薄差油层和表外储层的吸水动用状况,对解决萨北过渡带和三次加密注水井注入压力高、注入困难的问题具有一定的指导意义。由室内实验及现场实施效果表明,当表面活性剂的注入有效浓度为0.2%,注入半径为20～30m之间时,增注降压效果明显。     

Stability and thermophysical properties of fly ash nanofluid for heat transfer applications

Improving the performance of heat transfer fluids is altogether significant. The best approach for improving the thermal conductivity is the addition of nanoparticles to the base fluid. In the present study, specific heat, dynamic viscosity, and thermal conductivity of water-based Indian coal fly ash stable nanofluid for 0.1% to 0.5% volume concentration in the temperature range of 30 to 60°C has been investigated. To evaluate an average particle diameter of 11.5 nm, the fly ash nanoparticles were characterized with scanning electron microscopy and dynamic light scattering. Using zeta potential, the stability of nanofluid in the presence of surfactant Triton X-100 was tested. Thermal conductivity and viscosity of fly ash nanofluid increased, while specific heat decreased as volume concentration increased. The effect of temperature on the fly ash nanofluid was directly proportional to its thermal conductivity and specific heat and inversely proportional to viscosity.     

Condensation heat-transfer and pressure drop characteristics of refrigerant R-290/R-600a–oil mixtures in serpentine small-diameter U-tubes

Flow condensing experiments for refrigerant R-290, and R-600a mixed with the lubricating oil (EMKARATE RL 32H) in serpentine small-diameter (2.46 mm) U-tubes are reported. The tests were run at the saturation temperature of 40 °C, vapor qualities of 0.41–0.82, mass flux of 300–600 (kg/m²s) and inlet oil concentrations from 0 to 5 mass% oil. It was found that the condensation heat-transfer coefficients increased as mass flux values, vapor quality and the number of tube bends increased, but it decreased as the oil concentration increased. In addition, the two-phase pressure drops increased with increases in mass flux values, the number of tube bends and the oil concentration.     

Investigation of the performance of several chemical additives on inhibition of asphaltene precipitation

The inhibition effects of several chemical additives on asphaltene precipitation were investigated by the microscopic method. The additives consist of a synthesized deep eutectic solvent (SDES), a commercial inhibitor, and three surfactants, namely lauric acid, octyl phenol, and dodecyl amine. The results showed the octyl phenol with 500 mg/L concentration is similar to commercial inhibitor and later SDES had the maximum effects on delaying the asphaltene precipitation onset point. The mean particle size of asphaltene using octyl phenol, SDES, lauric acid, and dodecyl amine decreased about 55%, 41%, 24%, and 18%, respectively, compared to the oil sample without any chemical additives.     

微乳柴油的配制及其性能研究

根据微乳化理论选择油酸作为表面活性剂配制了多种配比的甲醇-柴油微乳化燃油、乙醇-柴油微乳化燃油,并讨论温度对微乳柴油稳定性的影响及在油酸中加入AEO2对复合表面活性剂总用量的影响。研究了该微乳化燃油体系的拟三元相图及在BH175F-1型柴油机上燃用的实验结果和尾气排放情况,结果表明,尾气中烟度、NO含量和CH含量大大低于0#纯柴油,烟度降低率最高可达50%,NO含量可下降35.4%,对环境保护十分有利。     

环境友好型原油脱硫剂效果评价与现场应用

JH6011环境友好型原油脱硫剂是一种油溶性-水中分散的复合有机化合物,其作用于原油中硫化物的脱硫条件为反应时间6~12h,脱硫温度50~70℃,脱硫剂与硫化物质量比为1∶1~2∶1。利用碘量法测定脱硫剂在模拟油(柴油)、原油中的脱硫率,结果显示其在模拟油中的脱硫率高于85%,在原油中的脱硫率高于80%。利用能量色散X-射线荧光光谱法测定其对原油中有机硫的脱除效果,平均脱除率为21.73%(主要为噻吩类)。现场应用时,总脱硫率也可达到80%以上,但需要根据原油硫含量、酸值、运动黏度等因素确定合适的添加量、脱硫温度和反应时间。硫含量较高或酸值较大时,可适当加大添加量,黏度较大时可适当提高脱硫温度或延长反应时间。     

Toward prediction of kinematic viscosity of biodiesel using a robust approach

Especially by using a renewable source of fuels such as biodiesel, a large number of high-quality researches have been performed on the reduction of pollution released from fossil fuels. Transesterification process is a common way for the production of biodiesel from vegetable oil, animal fat, and algae oil in the presence of alcohol and catalyst. Viscosity is one of the important physical fuel properties used in the selection of biodiesel. Experimental measurement of viscosity is a time-consuming task. Hence, in this contribution, applicability and performance of two artificial neural network-based models named least square support vector machine (LSSVM) and genetic algorithm-radial basis function (GA-RBF) for the prediction of kinematic viscosity of biodiesel were investigated. Root-mean-square error, coefficient of determination (R²), and average absolute relative deviation of each modeling were reported for each LSSVM and GA-RBF models. Modeling results show that the proposed LSSVM model is more accurate and robust than GA-RBF model.