Electrostatic destabilization of water-in-crude oil emulsions: Application to a real case and evaluation of the Aibel VIEC technology

In the current study, the Aibel Vessel Internal Electrostatic Coalescer (VIEC) technology was tested for a real case scenario encountered in the production train of a UK oil field. Depressurized samples were collected both upstream and downstream of the first stage separator. The separation performance was discussed with respect to water cut and droplet size distribution of the emulsions, and the effect of chemical treatment. Issues with respect to representative sampling and testing have been discussed. The application of an external AC electrical field has been shown to significantly enhance the separation of the aqueous phase from tight emulsions, both when it was used alone and in combination with a commercial demulsifier. By using the VIEC technology, the time for separation could be reduced from 8 min to 2 min and the overall BS&W in the emulsions was improved from 45% or 60% to a residual water content of 5-20%. Destabilization of a 45% water-in-oil emulsion by electrical and chemical treatment (20/40 ppm) produced oil in the 2-7% BS&W range whereas the corresponding tests without applying an electrostatic field led to a BS&W greater than 25%. The achieved results strongly suggest that the VIEC technology can resolve the stable emulsion bands encountered in the Schiehallion train and add flexibility or increased production rate to the process. The results also suggest the importance of further studies on the destabilization performances achieved by electrostatic means.     

原油快速评价在原油优化调合中的应用

介绍了企业在实施原油优化调合系统中为了稳定原油性质、实时优化调合配方、实现在线原油调合而开发的原油快速评价模块。通过该模块的使用,大大降低了原油评价的时间,能稳定、实时地检测各调合支路及总路的原油评价性质,为优化调合模块提供了准确的性质数据,实现了调合配方的实时优化,达到原油的在线调合目标,提高了装置运行的平稳率,为企业优化生产、降本增效提供了有力支撑。     

Two-stage ultrasonic irradiation for dehydration and desalting of crude oil: A novel method

In this study, a new methodology is proposed based on using two periods of ultrasonication for the dehydration and desalting of heavy crude oil. For this purpose, ultrasonic irradiations are used under specified conditions such as irradiation input power, irradiation time and gap time after irradiation within a batch standing-wave resonator reactor. A serious problem with the commonly used single stage operation is that the enlarged water drops containing soluble salts in oil need to be settled for at least 60 min. To reduce this time, we proposed “two-stage ultrasonic irradiation at the equal irradiation times”. This methodology proved to be an efficient way with the least settling time required. The results showed that the ultrasonic irradiations with irradiation input powers of 75 W for primary irradiation and 50 W for secondary irradiation (75–50 W) at the equal irradiation times of 45 s considerably decreased the settling time to 5(×2) min. Moreover, dehydration rate was more than 96% and also the final salt content was up to 2.56 PTB, which can meet the need of refineries. Micrographs obtained also confirmed efficiency of the methodology which caused the water drop size to increase by 40% after each step of the process.     

The viscoplastic properties of crude oil-water interfaces

The breaking of water-in-crude oil emulsions is a major challenge in the conventional petroleum industry, while oil-in-water emulsions present similar issues in commercial oilsands extraction processes. The stability of these emulsions can be attributed to complex rheological properties of the crude oil-water interface. Novel micromechanical techniques are developed that allow direct measurements of interfacial behaviour of emulsion drops. In these techniques, individual emulsion drops are elongated using micropipettes, where one micropipette is shaped into a cantilever for force measurements. As such, the surface behaviour of a drop is recorded in stress-strain experiments. In an alternative technique, the extended drop is released from a micropipette, and its natural, tension-driven relaxation is observed.The surface behaviour of bitumen (a heavy crude oil) emulsion drops in aqueous environments, that include dissolved calcium ions and suspended montmorillonite clays, is studied. The plasticity and other surface properties of these bitumen drops are discussed. A simple, lumped-parameter model is developed to describe the recovery of a bitumen drops to their final non-spherical shapes.     

Acoustically aided separation of oil droplets from aqueous emulsions

A novel method for recovering the oil phase from aqueous emulsions has been developed. The method applies a low-intensity, resonant ultrasonic field within a rectangular chamber, which is optionally filled with a highly porous medium. Oil droplets dispersed in water have negative acoustic contrast factor and thus are driven to the pressure antinodes of the standing wave field under the influence of acoustic radiation forces. Subsequent coalescence and/or wetting onto the internal surfaces of the chamber occur. Three types of porous media (an unconsolidated bed of 3-mm glass beads, aluminum mesh or reticulated polyester mesh) having pore sizes two to three orders of magnitude larger than droplets being collected were used. The oil collection was found to be sensitive to the natural affinity between the oil and the porous medium as well as its porosity. Of the three media studied, the polyester mesh was found to be the best in terms of the percentage oil collection while the bed of glass beads performed the poorest. The oil collection was found to be highly sensitive to the residence time of the emulsion in both the porous medium and acoustic field. Oil collection also showed expected trends with applied electrical power, but it was not found to be strongly dependent on the internal surface area of the mesh for the range of feed concentration tested. These experiments enable a preliminary understanding about the mechanisms underlying the separation process.     

Application of ultrasound on crude oil pretreatment

The ultrasonic irradiation for crude oil pretreatment to enhance desalting process was investigated. The intensity and irradiation time of ultrasound were studied. The settling time and the temperature of treatment for crude oil were also studied. Micrographs in this paper showed that the sizes of water drops were enlarged by more than 30% after the proper ultrasonic irradiation. The crude oil was pretreated for 5 min at 80 °C in the standing-wave field with frequency of 10 kHz and with ultrasonic intensity of 0.38 W cm⁻². After the pretreatment, the dewatering rate and desalting rate were up to 92.6% and 87.9%, respectively in 90 min of settling time. The resulting final salt content of 3.85 mg L⁻¹ is acceptable for refinery.     

含硫和高硫原油的加工技术

介绍了俄罗斯原油、委内瑞拉原油的一般性质及目前国内首套加工俄罗斯原油的5.5 Mt/a常减压装置的主要工艺路线和新技术特点,并针对俄罗斯原油的性质和该常减压装置的设计特点、运行中存在的问题和采取的对策及建议进行了分析讨论,如装置对加工俄罗斯原油的适应性问题、以及轻烃回收问题等,同时也对3.5 Mt/a常减压装置掺炼委内瑞拉高硫原油以及第二次加工装置的运行情况加以分析,为国内大量加工俄罗斯原油及委内瑞拉原油装置的设计提供了良好的借鉴经验。     

Effects of cultivar and tempering procedures on crude soybean oil volatiles

The effects of soybean cultivar and tempering procedures on crude soybean oil volatiles were investigated by gas chromatography/mass spectrometry (GC/MS). Varietal differences in volatiles were not obvious. Trends in volatile contents due to tempering were noted primarily when comparing mean peak areas of these compounds in oils stored 16 days at 60°C. Differences in volatiles in response to tempering were not apparent in oils that had not been stored. Equilibration of beans with water resulted in oils with higher volatile contents than those from untempered beans. Steaming lowered volatiles from equilibrated values, and pressure steaming had an even more dramatic lowering effect.     

Novel evaluation method for the water- in- oil (W/O) emulsion stability by Turbidity Ratio Measurements

The turbidity ratio method of evaluating the stabilities of water-in-oil emulsions has been established with two wavelengths (450 and 850 nm) by taking the intensity ratio of two beams. The slopes of turbidity ratio of several water-in-oil emulsions with time were calculated to evaluate the emulsion stabilities at different HLB (Hydrophilie-Lipophile Balance), the amounts of emulsifiers, and water contents. The results of the turbidity ratio technique were consistent with the amount of phase separation of emulsions incubated for 30 days at room temperature. From the turbidity ratio measurements, we determined that the required HLB of diesel oil was about 6.0, and that the stability of emulsion increased with the amount of emulsifier. The increasing amount of the water showed a negative effect on emulsion stability. Finally, this method provides a useful tool for the quick evaluation of the required HLB and the condition of emulsification throughout this study.     

Experimental investigation of foam performance in the presence of crude oil

The foam performance in the presence of oil plays an important role in foam application in enhancing oil recovery. The present study systematically investigated the effect of oil type, oil content, surfactant type, surfactant concentration, alkane chain length, salinity, and polymer concentration on foam performance in both the absence and presence of oil. The results showed that oil viscosity and oil density as well as oil component all contributed to foam performance in the presence of oil. Within a certain oil content, both light oil and heavy oil had a positive effect on foam, but heavy oil had a higher tendency to stabilize the foam. The order of foam performance by different surfactants was changed by the oil. It is noteworthy that heavy oil is detrimental to sodium dibutyl naphthalene sulfonate (BM) foam. Light oil can improve foam performance while heavy oil can harm foam in some specific cases. Lower salinity, longer alkane chain length, higher surfactant concentration and the presence of a polymer all benefited foam in the presence of crude oil.     

大榭老化原油脱水工艺实验研究

以含水率为40.89%的老化原油为研究对象,采用超声波辅助老化原油破乳脱水-离心分离的方法对老化原油进行脱水实验。对破乳剂进行筛选,最终确定聚醚类破乳剂D205A为最佳。考察了破乳剂质量浓度、超声反应温度、超声反应时间、沉降温度以及离心时间对老化原油脱水效果的影响。结果表明,适宜的脱水工艺条件为:聚醚类破乳剂D205A的质量浓度为140 mg/L,超声波温度为65℃,超声波时间30 min,沉降温度85℃,离心时间30 min。依照此优化实验条件可以将初始含水率为40.89%的老化原油的含水率降至4.29%。     

大榭老化原油脱水工艺实验研究

以含水率为40.89%的老化原油为研究对象,采用超声波辅助老化原油破乳脱水-离心分离的方法对老化原油进行脱水实验。对破乳剂进行筛选,最终确定聚醚类破乳剂D205A为最佳。考察了破乳剂质量浓度、超声反应温度、超声反应时间、沉降温度以及离心时间对老化原油脱水效果的影响。结果表明,适宜的脱水工艺条件为:聚醚类破乳剂D205A的质量浓度为140 mg/L,超声波温度为65℃,超声波时间30 min,沉降温度85℃,离心时间30 min。依照此优化实验条件可以将初始含水率为40.89%的老化原油的含水率降至4.29%。     

Influence of oil phase concentration on droplet size distribution and stability of oil‐in‐water emulsions

The objective of this study was to investigate the effect of oil phase concentration, at different emulsification conditions concerning homogenization time and emulsifier content, on droplet size distribution and stability of corn oil‐in‐water emulsions. Emulsions were prepared with 3, 5, 10, and 20% w/w triethanolamine oleate (calculated on oil amount), 0.53% w/w carboxymethylcellulose (calculated on water amount), and 5, 10, 20, 30, or 40% w/w oil, and homogenized 5, 10, 20, and 60 min. It was found that increase in oil phase concentration led to decrease in specific surface area and increase in polydispersity of emulsion at lower emulsifier concentration and less intense homogenization. At emulsifier concentrations ≤10% and homogenization time ranges of 20–60 min the non‐monotonous variation in droplet size parameters with oil concentration was observed, as a result of the interaction between triethanolamine oleate and carboxymethylcellulose, which were confirmed by viscosity measurements. However, at emulsifier concentration of 20% an increase in specific surface area and decrease in polydispersity with the increase in oil concentration occurred due to an increase in equilibrium concentration of emulsifier in the continuous phase. Further, influence of oil concentration on emulsion creaming stability was found to be independent on emulsifier concentration and homogenization time. Therefore, a decrease in creaming with increase in oil concentration was observed in all the examined triethanolamine oleate (TEAO) concentration and homogenization time ranges. Practical applications: Emulsions are colloidal systems which can be encountered in different industrial sectors, such as food, pharmaceutical, cosmetics, oil industry, etc. Determination of the droplet size of emulsion is probably the most important way of their characterization, since it influences the properties of emulsion such as rheology, texture, shelf life stability, appearance, taste, etc. The size of the droplets depends on a wide range of parameters. One of them is certainly the concentration of the oil phase. However, since the impact of one parameter is often influenced with the intensity of the other variable involved in the emulsion generation, the aim of the present work was to examine the effect of corn oil concentration on droplet size parameters and stability of oil‐in‐water emulsions at different emulsification conditions. Therefore a step toward creation of emulsions with desired final properties was made.     

正交设计在微波辐射原油脱水中的应用研究

研究了微波辐射对原油乳状液脱水的机理及其3个主要影响因素,用正交实验设计法考察微波辐射对原油乳状液脱水的最佳实验条件,以达到较好的脱水效果。采用MSP-100D微波消解系统对水质量分数为50％的大庆原油乳化液进行微波辐射实验。通过极差和方差分析可知,在影响大庆原油乳化液脱水率的3个因素中系统压力值影响最大,微波辐射功率其次,微波辐照时间影响最小。在微波辐射功率为400W,辐照时间为10min,系统压力值为0．3MPa,水质量分数为50％的大庆原油乳化液的平均脱水率高迭93．9896。实验结果表明．微波辐射原油脱水具有效率高,时间短,无污染和节约能源等优点,有良好的工业化应用前景。     

高酸原油脱酸技术的研究进展

分析了常规高酸原油脱酸工艺的不足,介绍了近几年国内外对高酸原油脱酸的新工艺方法,如离子液体原油脱酸、脱酸剂技术脱酸、高温热解脱酸等方法。新技术将对原油脱酸技术的发展起到一定的推动作用,其中咪唑型阳离子脱酸具有较大的应用前景。     

针对原油性质变化的常减压先进控制研究与应用

针对原油性质变化对常减压装置操作造成的巨大困难,提出了一种稳定原油性质和引入原油性质参数到软测量和控制模型的先进控制综合解决方案。一方面,对待混炼的多种原油进行调度和掺炼比优化,使实际进入常减压装置进行炼制的调合原油性质相对稳定,装置操作参数变化较小,减少工作点大幅变化过程中所产生的波动。另一方面,针对仍然存在的原油性质小幅度变化,在软测量和预测控制建模中引入反映原油性质的馏程参数,克服原油性质变化所引起的扰动。现场实际装置的应用结果说明了此综合方案的有效性。     

原油加剂强化蒸馏的研究进展

为了提高轻质油收率,解决石油市场的供需矛盾,人们提出并开发了原油强化蒸馏技术。为此,介绍了加剂强化蒸馏作用机理,归纳了活化剂的设计原则和主要成分,通过对原油强化蒸馏的实验研究和工业应用的总结,指出了其目前存在的问题,并对原油强化蒸馏今后的发展提出一些建议。     

Distinctive combustion stages of single heavy oil droplet under microgravity

This report presents an investigation on the combustion of single droplets comprised of heavy oil and oil mixtures blending diesel light oil (LO) and a heavy oil residue (HOR). The tests were conducted in a microgravity facility that offered 10 s of free-fall time. Fine wire thermocouples supported the droplets, resulting in a measurement of droplet temperature history. Additional data were the droplet and flame size history. The results identified four distinctive burning stages between ignition and extinction for heavy oil (C class) and HOR-LO blends. They are, in succession, the start-up, inner evaporation, thermal decomposition (pyrolysis) and polymerization stages. The start-up stage denoted an initial transient period, where the LO components burned from the droplet surface and the droplet temperature increased rapidly. The latter three stages featured pronounced droplet swellings and contractions caused by fuel evaporation and decomposition inside the droplet. An evaporation temperature demarcated the start-up stage from the inner evaporation stage, and this temperature corresponded to a plateau in the temperature history of the droplet. Two additional temperatures, termed the decomposition and polymerization temperatures, indicated the ends of the evaporation and decomposition stages. These temperatures were similarly identified by plateaus or inflection points in the time-temperature diagram. The evaporation temperature gradually decreased with increasing the initial LO mass fraction in the droplet, whereas the other two temperatures were almost independent of the oil composition. All three temperatures increased with decreasing initial droplet diameter, but the dependence was very slight. Based on the results, the combustion of heavy oil droplets appears to be dominated by a distillation-like vaporization mechanism, because of the rapid mass transport within the droplets caused by the disruptive burning.     

超声波在辽河原油脱钙中的应用

针对辽河高钙原油研制开发了无磷不含金属的高效脱钙剂,利用原子吸收光谱法对原油在超声波作用下实验前后的钙、镍、铁及镁4种金属含量进行分析,考察了反应时间、超声波的频率及强度对原油脱金属率的影响.结果表明,注水率为10%、反应时间为15 min,超声波的频率28 kHz及强度8W/cm时,原油的脱钙率达到90%以上,其它3种金属的脱除率达到70%以上.     

原油脱水站油水分离效果的影响因素和改善措施

针对近年来大庆油田部分原油脱水站存在的问题,研究了影响原油脱水站油水分离效果的主要因素,提出了改进破乳剂的性能和投加机制,降低游离水脱除器进液中机械杂质含量等提高原油脱水站油水分离效果的改善措施。对采出液处理中应用的破乳剂配方及其加药点设置,沉降罐上部污油回收处理工艺进行了改进。在实际应用中显著改善了大庆油田采出液的油水分离效果,电脱水器运行稳定性显著提高,出矿净化原油水含量低于0.3%的控制指标,沉降罐上部油层厚度可控制在0.3m以下,聚驱沉降罐和水驱沉降罐放水含油量可分别降低到500mg/L和300mg/L的控制指标以下。