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1.
High‐temperature/high‐salinity (HTHS) reservoirs contain a significant fraction of the world's remaining oil in place and are potential candidates for enhanced oil recovery (EOR). Selection of suitable surfactants for such reservoirs is a challenging task. In this work, two synthesized zwitterionic surfactants bearing a saturated and an unsaturated tail, namely 3‐(N‐stearamidopropyl‐N,N‐dimethyl ammonium) propanesulfonate and 3‐(N‐oleamidopropyl‐N,N‐dimethyl ammonium) propanesulfonate, respectively, were evaluated. The surfactant with the unsaturated tail showed excellent solubility in synthetic seawater (57,643 ppm) and in formation brine (213,734 ppm). However, the unsaturated surfactant with a saturated tail showed poor solubility, and therefore it was not evaluated further. The thermal stability of the synthesized unsaturated surfactant solution in seawater was evaluated by heating the solution at 90 °C in a sealed aging tube for 2 weeks. The thermal stability of the unsaturated surfactant was confirmed by FTIR and NMR analysis of the aged samples at such harsh conditions. The critical micelle concentration (CMC) of the synthesized unsaturated surfactant in seawater was 1.02 × 10?4 mol L?1, while the surface tension at CMC was 30 mN m?1. The synthesized unsaturated surfactant was able to reduce the oil–water interfacial tension to ~10?1 mN m?1 at different conditions. A commercial copolymer of acrylamide and 2‐acrylamido‐2‐methylpropane sulfonic acid (AM‐AMPS) was tested for EOR applications in HTHS conditions. The addition of the synthesized unsaturated surfactant to the AM‐AMPS copolymer increased the viscosity of the system. The increase in oil recovery by injecting the unsaturated surfactant solution and the surfactant–polymer mixture in solution was 8 and 21%, respectively. The excellent properties of the synthesized unsaturated surfactant show that surfactants with an unsaturated tail can be an excellent choice for HTHS reservoirs.  相似文献   

2.
By mixing an aqueous solution of tertiary amine, N,N‐dimethylethanolamine (DMEA), with naphthenic acid (RCOOH) derived from heavy oil, a CO2 switchable zwitterionic surfactant (RCOO?DMEAH+) aqueous system was constructed. The CO2 switchability of this zwitterionic surfactant was confirmed by visual inspection, pH measurements, and conductivity tests, i.e., the RCOO?DMEAH+ decomposed into RCOOH, DMEAH+ and HCO3? after bubbling CO2 through but switched back to its original state by subsequent bubbling N2 through at 80 °C to remove the CO2. The interfacial tension tests of heavy oil in DMEA aqueous solutions indicated that the solution containing 0.5 wt% of DMEA and 0.2 wt% of NaCl resulted in the lowest interfacial tension. The O/W emulsion formed when aqueous solutions of DMEA were used to emulsify heavy oil exhibited the best performance when the oil/water volume ratio, DMEA concentration, and NaCl concentration were 65:35, 0.5 and 0.2 wt%, respectively. The feasibility of pipeline transport of the O/W heavy oil emulsion was evaluated. The results illustrated that the demulsification of the O/W emulsion after transport could be easily realized by bubbling CO2 through. Although demulsification efficiency still needs to be improved, the recycling of the aqueous phase after demulsification by removal of CO2 looks promising.  相似文献   

3.
Esters of castor oil and hydrogenated castor oil were prepared with C6, C12, C16, C18 fatty acids, using tetra‐n‐butyl titanate as a catalyst and n‐butyl benzene as a water entrainer. Physical properties such as melting point, refractive index, viscosity, and specific gravity of these esters were measured. Slip melting points of the esters were very low in both cases. These esters did not crystallize even at low temperature. The highest slip melting point obtained was 21 °C with stearoyl hydrogenated castor oil ester and lowest slip melting point obtained was —6 °C with hexanoyl castor oil ester.  相似文献   

4.
Three different cases were selected to study the effect of physicochemical formulation on interfacial rheology properties of surfactant–oil–water (SOW) systems by increasing the complexity of the system from a basic case. This was performed by changing the normalized hydrophilic–lipophilic deviation (HLDN) to attain the optimum formulation at HLDN = 0. Two types of SOW systems were studied: the first one used an ionic surfactant with a salinity scan, and the second one a mixture of two nonionic surfactants in a formulation scan produced by changing their proportion. Both of them contained cyclohexane as a pure oil phase, without alcohol. Sec-butanol was then added as a co-surfactant with hardly any formulation influence on HLDN. The complexity in interfacial rheology was then increased by changing the oil to a light crude with low asphaltene content. The interfacial rheology is also reported for a realistic system with a high asphaltene content comprised of crude oil diluted in cyclohexane with a conventional surfactant and a commercial demulsifier. The findings confirm that at optimum formulation and whatever the scanning variable (salinity, average ethylene oxide number in the nonionic surfactant mixture, or surfactant/demulsifier concentration), the interfacial tension, and interfacial elastic moduli E, E′, and E″ exhibit a deep minimum. These observations are related to the acceleration of the surfactant exchanges between the interface, oil, and water, near the optimum formulation. Several arguments are put forward to explain how these findings could contribute to the decrease in emulsion stability at HLDN = 0.  相似文献   

5.
The interfacial rheology of surfactant mixtures (SBT and Tween® 80) at the oil/water interface is investigated using toluene as a model oil. The surfactant ratio in the mixed system has an important impact on the interfacial properties. After adding Tween® 80, the interfacial tension and modulus of SBT show remarkable changes. Compared with the individual SBT or Tween® 80 systems, the interfacial properties of the mixed surfactant system improve, especially at a 1:1 ratio. At the optimum ratio, synergistic adsorption takes place resulting in improved asphalt emulsion stability.  相似文献   

6.
Injected chemical flooding systems with high salinity tolerance and fast‐dissolving performance are specially required for enhancing oil recovery in offshore oilfields. In this work, a new type of viscoelastic‐surfactant (VES) solution, which meets these criteria, was prepared by simply mixing the zwitterionic surfactant N‐hexadecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (HDPS) or N‐octyldecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (ODPS) with anionic surfactants such as sodium dodecyl sulfate (SDS). Various properties of the surfactant system, including viscoelasticity, dissolution properties, reduction of oil/water interfacial tension (IFT), and oil‐displacement efficiency of the mixed surfactant system, have been studied systematically. A rheology study proves that at high salinity, 0.73 wt.% HDPS/SDS‐ and 0.39 wt.% ODPS/SDS‐mixed surfactant systems formed worm‐like micelles with viscosity reaching 42.3 and 23.8 mPa s at a shear rate of 6 s?1, respectively. Additionally, the HDPS/SDS and ODPS/SDS surfactant mixtures also exhibit a fast‐dissolving property (dissolution time <25 min) in brine. More importantly, those surfactant mixtures can significantly reduce the IFT of oil–water interfaces. As an example, the minimum of dynamic‐IFT (IFTmin) could reach 1.17 × 10?2 mN m?1 between the Bohai Oilfield crude oil and 0.39 wt.% ODPS/SDS solution. Another interesting finding is that polyelectrolytes such as sodium of polyepoxysuccinic acid can be used as a regulator for adjusting IFTmin to an ultralow level (<10?2 mN m?1). Taking advantage of the mobility control and reducing the oil/water IFT of those surfactant mixtures, the VES flooding demonstrates excellent oil‐displacement efficiency, which is close to that of polymer/surfactant flooding or polymer/surfactant/alkali flooding. Our work provides a new type of VES flooding system with excellent performances for chemical flooding in offshore oilfields.  相似文献   

7.
To enhance oil recovery in high‐temperature and high‐salinity reservoirs, a novel fatty amine polyoxyethylene ether diethyl disulfonate (FPDD) surfactant with excellent interfacial properties was synthesized. The interfacial tension (IFT) and contact angle at high temperature and high salinity were systematically investigated using an interface tension meter and a contact angle meter. According to the experimental results, the IFT between crude oil and high‐salinity brine water could reach an ultra‐low value of 10?3 mN m?1 without the aid of extra alkali at 90°C after aging. The FPDD surfactant has strong wettability alternation ability that shifts wettability from oil‐wet to water‐wet. The FPDD surfactant with a high concentration also has good emulsion ability under high‐temperature and high‐salinity conditions. Through this research work, we expect to fill the lack of surfactants for high‐temperature and high‐salinity reservoirs and broaden its great potential application area in enhanced oil recovery.  相似文献   

8.
The esterification of castor oil with lauric acid was investigated using tetra n-butyl titanate (TBT), SnCl2·2H2O (stannous chloride), CoCl2·6H2O (cobalt chloride), and (CH3COO)2Zn·2H2O (zinc acetate dihydrate) as catalysts. Effects of catalyst concentration and reaction temperature on the progress of the reaction were investigated. TBT was the best catalyst for the esterification of castor oil with lauric acid at temperatures lower than 200°C. The reaction was first order with respect to each reactant. The activation energy for the esterification reaction of castor oil with lauric acid using TBT was 26.69 kcal/mol. The rate constants obtained for the esterification of castor oil with decanoic, lauric, palmitic, and stearic acids were nearly the same (15.80, 15.44, 15.06, and 14.67 mL mol−1 min−1), as were the rate constants obtained for the reaction of castor oil and hydrogenated castor oil.  相似文献   

9.
High‐oleic soybean oil is chemically functionalized in order to mimic the structure and physical properties of hydrogenated castor oil (HCO). The resulting wax‐like material is evaluated for use as an alternative to other commercial wax coatings for the postharvest treatment of fresh citrus fruit. The racemic nature of the material inhibits ordered crystalline arrangement and negatively affects its relative crystallinity (17.7%), hardness (0.59 ± 0.04 mm?1), and melting profile (44–46 °C), with respect to HCO oil (37.7%, 5.33 ± 0.01 mm?1, 83–87 °C). Nevertheless, compounding the new material with carnauba wax (CAR) imparts a very attractive gloss and prevents moisture loss significantly better than polyethylene, shellac, and CAR‐based coatings. Compounding the hydroxy‐functionalized high‐oleic soybean wax may potentially reduce dependence on imported CAR and other ingredients used in citrus coating emulsion formulations. Practical Applications: The soybean oil‐derived material described in this contribution provides two key performance characteristics desired by citrus growers and packing houses: an efficient barrier to moisture loss and an attractive shine. The synthesis of the hydroxy‐wax is facile and mild, and the materials can be readily formulated into emulsions as required for fruit coating applications. Use of the formulated coating can be extended to other agricultural commodities such as avocados, melons, and stone fruit.  相似文献   

10.
A series of castor oil adducts were synthesized by esterification of castor oil with acid anhydrides: phthalic, maleic and succinic anhydrides. The chemical structure of castor oil and the prepared adducts were characterized by means of IR and 1H NMR spectroscopy. The number‐average and weight‐average molecular weights were measured by gel permeation chromatography. The electrical properties were studied through the permittivity, dielectric loss and conductivity measurements, which are considered to be in the range of electrical insulation. The electrical conductivity, which describes the ionic mobility of the systems, was found to be in the range of 10–9 to 1012 S/cm. This indicates that castor oil and its esters could be used for antistatic applications. The viscosity η and the activation energy Eη, obtained from the dependency of viscosity on temperature using the Arrhenius equation, were found to increase with increasing molecular weight of the system. The effect of different concentrations of castor oil and its esters on the growth activities of the sugar beet pathogens R. solani and S. rolfsii was studied through the determination of percent germination, average length of hyphal extensions, dry mass yield and the production of sclerotia. The obtained data indicate that the esterification of castor oil with anhydrides improves the antifungal activity.  相似文献   

11.
In order to enhance oil recovery from high‐salinity reservoirs, a series of cationic gemini surfactants with different hydrophobic tails were synthesized. The surfactants were characterized by elemental analysis, infrared spectroscopy, mass spectrometry, and 1H‐NMR. According to the requirements of surfactants used in enhanced oil recovery technology, physicochemical properties including surface tension, critical micelle concentration (CMC), contact angle, oil/water interfacial tension, and compatibility with formation water were fully studied. All cationic gemini surfactants have significant impact on the wettability of the oil‐wet surface, and the contact angle decreased remarkably from 98° to 33° after adding the gemini surfactant BA‐14. Under the condition of solution salinity of 65,430 mg/L, the cationic gemini surfactant BA‐14 reduces the interfacial tension to 10?3 mN/m. Other related tests, including salt tolerance, adsorption, and flooding experiments, have been done. The concentration of 0.1% BA‐14 remains transparent with 120 g/L salinity at 50 °C. The adsorption capacity of BA‐14 is 6.3–11.5 mg/g. The gemini surfactant BA‐14 can improve the oil displacement efficiency by 11.09%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46086.  相似文献   

12.
Surfactant flooding plays a critical role in chemically enhanced oil recovery over the last half century, with the widely accepted mechanism of ultralow interfacial tension (IFT) by forming middle-phase microemulsions with high concentration of a lead surfactant and a cosurfactant. However, it is found practically from field trials that high oil recovery efficiency can be obtained from low concentration surfactant flooding without forming microemulsions, and the principle behind has not been clearly unraveled yet. Here the solubilization of paraffin oil by the micelles formed with a commercial enhanced oil recovery surfactant, raw naphthenic arylsulfonates (NAS), was investigated using ultraviolet-visible (UV–Vis) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). It is found that paraffin oil can be well solubilized inside the NAS micelles, and mainly localized in the hydrophobic core of the micelles. The solubilization capacity of NAS micelles increases with increasing its concentration, and the size of micelles increases, but morphology of the micelles remains spherical with increasing the amount of paraffin oil, along with an appearance transition from transparent to opaque until the maximum solubilization capacity is reached. Core flooding results with crude oil indicate that in the presence of 0.24 wt.% polymer, addition of 0.1, 0.2, 0.5, and 1.0 wt.% NAS can get oil recovery factor of 24.1%, 27.0%, 30.5%, and 38.3%, which increases linearly with increasing NAS concentration though with the interfacial tension values only in the magnitude of 10−2 mN m−1 level. These findings prove preliminarily micellar solubilization can help increasing oil recovery efficiency even without ultralow IFT.  相似文献   

13.
Castor oil has many industrial uses because of its high content (90 %) of the hydroxy fatty acid, ricinoleic acid (OH1218:19). Lesquerella oil containing lesquerolic acid (Ls, OH1420:111) is potentially useful in industry. Ten molecular species of diacylglycerols and 74 molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil were identified by electrospray ionization mass spectrometry as lithium adducts of acylglycerols in the HPLC fractions of lesquerella oil. Among them were: LsLsO, LsLsLn, LsLsL, LsLn–OH20:2, LsO–OH20:2 and LsL–OH20:2. The structures of the four new hydroxy fatty acid constituents of acylglycerols were proposed by the MS of the lithium adducts of fatty acids as (comparing to those in castor oil): OH1218:29,14 (OH1218:29,13 in castor oil), OH1218:39,14,16 (OH18:3 not detected in castor oil), diOH12,1318:29,14 (diOH11,1218:29,13 in castor oil) and diOH13,1420:111 (diOH20:1 not detected in castor oil, diOH11,1218:19 in castor oil). Trihydroxy fatty acids were not detected in lesquerella oil. The differences in the structures of these C18 hydroxy fatty acids between lesquerella and castor oils indicated that the polyhydroxy fatty acids were biosynthesized and were not the result of autoxidation products.  相似文献   

14.
In our previous report, the mixed cationic/anionic surfactant system consisting of N-dodecyl-N-methylpyrrolidinium bromide (L12) and sodium dodecyl sulfate (SDS) showed good interfacial tension (IFT) reduction of water/model oil (Vtoluene:V n-decane = 1:1). In the present study, the effects of divalent salts (MgCl2 or CaCl2) on the interfacial activity were systematically evaluated. The additional Mg2+ ions greatly reduced the IFT to an ultralow value, whereas Ca2+ ions caused the generation of the precipitates and resulted in increased IFT values. The precipitates disappeared in binary divalent salt solutions, and the IFT values remained at a low level. Based on the valence, polarizability, and hydrated radius of the ions, we proposed a model to explain the abnormal changes. The effects of NaCl and temperature were investigated to further verify our proposed mechanism. Moreover, the additional divalent salts obviously enhanced the stability of L12/SDS stabilized emulsions.  相似文献   

15.
It is an urgent issue to enhance oil recovery for unconventional reservoirs with high salinity. Focused on this topic, salt addition is a powerful tool to motivate the surfactant assembly at the water/oil interface and improve the interfacial activity. We used a cationic surfactant cetyltrimethylammonium bromide (CTAB) and an anionic salt dicarboxylic acid sodium (CnDNa) to construct gemini-like surfactants at the interface and evaluated their ability to reduce the interfacial tension (IFT) between model oil (toluene and n-decane, v:v = 1:1) and water. Interestingly, the fabrication of a (CTAB)2/C4DNa gemini-like surfactant was hardly achieved at the fresh water/model oil interface, but accomplished at the brine/model oil interface. At a high NaCl concentration (100,000 mg L−1), the IFT value is reduced to 10−3 mN m−1 order of magnitude, which is generally desired in practical applications. The control experiments displacing the surfactant type and the spacer length further confirmed the NaCl effects on the interfacial assembly.  相似文献   

16.
The dynamic interfacial tension (IFT) of ethoxylated fatty acid methyl ester solutions against n‐alkanes, kerosene, and diluted heavy oil have been investigated by spinning drop interfacial tensiometry. The influences of ethylene oxide (EO) groups and alkyl chain length on IFT were investigated. The experiment results show that the water solubility decreases with an increase in alkyl chain length or a decrease in EO groups. The ability to lower the interfacial tension against hydrocarbons improves with both increasing alkyl chain length and EO group at the best hydrophilic‐lipophilic balance, which can be attributed to the enhancement of the interfacial hydrophobic interactions and the rearrangement of interfacial surfactant molecules. The mixed adsorption of surfactant molecules and surface‐active components may reduce IFT to a lower value. C18=E3 shows the best synergism with surface‐active components. However, the IFT values against pure crude oil are obviously higher than those against hydrocarbons, which may be caused by the nature of heavy oil.  相似文献   

17.
Alkali-surfactant-polymer (ASP) flooding has been considered to be one of the useful tertiary oil recovery techniques. However, field tests in China have revealed that serious side effects may occur due to using alkali. Thus alkali-free SP flooding is more favorable in China. Unfortunately, surfactants effective in ASP flooding are usually ineffective in the absence of alkali and new surfactants need to be designed. In this paper N-(3-Oxapropanoxyl)dodecanamide as a pure compound and a mixture of homologues with narrow EO number distribution, synthesized by the reaction of lauroyl chloride with diglycolamine and addition of one ethylene oxide to coconut monoethanolamide respectively, are examined for their adaptability in SP flooding. It is found that, when mixed with betaines, both products can reduce Daqing crude oil/connate water interfacial tension to a magnitude of 10−3–10−4 mNm−1 at 45 °C in a wide surfactant concentration range, 0.01–0.5 wt%, and oil displacement tests using natural cores indicates that a tertiary oil recovery of 18.6 ± 0.4% OOIP can be achieved by SP flooding with the N-(3-Oxapropanoxyl)dodecanamide as the main surfactant without adding any alkaline agent and neutral electrolyte. N-(3-Oxapropanoxyl)dodecanamide, as a nonionic surfactant without a cloud point and producible industrially from renewable materials, is an ideal surfactant for SP flooding in the absence of an alkaline agent.  相似文献   

18.
In this study several oil press cakes were investigated as exclusive substrates for different moulds and yeasts for the production of flavor‐active decalactones via solid‐state fermentation (SSF). Experiments are focused on pre‐treatment methods for olive cake to remove antimicrobial phenolic substances contained in the oil cake disturbing or even inhibiting microbial growth. Choosing Ceratocystis moniliformis as the reference microorganism best results were obtained by a combination of hot water flushes and enzymatic treatment of the cake. Fermentation with sunflower, olive and linseed cake did not lead to lactone formation in detectable amounts although all of these substrates provided good microbial growth. On castor cake, however, five microorganisms have synthesized the requested decalactones via SSF. Thus fermentation of the fungus Moniliella suaveolens on this substrate resulted in a maximum concentration of γ‐decalactone of 180.7 mg·kg?1 dry matter without optimization. Another δ‐lactone, 6‐pentyl‐α‐pyrone, was produced in small amounts by the fungus Trichoderma harzianum on castor cake.  相似文献   

19.
In this work, a number of urethane-modified polyesteramide (UmPEA) films were developed from mahua and castor oils, which are renewable resources. Mahua oil and diethanolamine were reacted to form mahua fattyamide, which was then reacted with itaconic acid to prepare polyesteramide. In order to make the UmPEA films, different proportions of polyesteramide and castor oil as polyols were reacted with isophoronediisocyanate. The UmPEA films showed excellent chemical resistance against water, acid, alkali, salt, and organic solvents and were found insoluble in common organic solvents. The thermal stability of the UmPEA films was investigated through TGA and DSC analyses, and their Tg values are between 69.1°C and 56.1°C for UmPEA films, which indicated that a higher content of CO enhances the Tg, and it was also found that the films were highly stable up to 230°C. The Ea values [224 kJ mol−1 (Tp1) and 226 kJ mol−1 (Tp2)] indicate that the castor oil enhances the thermal stability of the films due to better cross-linking density occurring through the high hydroxyl groups of CO as the polyol which also showed better flame retardancy in the synthesized UmPEA films. Our findings demonstrate that the newly developed UmPEA films can be potent coating materials.  相似文献   

20.
Partially hydrogenated oils (PHO) have been removed from the food supply due to adverse effects on risk for coronary heart disease (CHD). High-oleic soybean oils (HOSBO) are alternatives that provide functionality for different food applications. The objective of this study was to determine how consumption of diets containing HOSBO compared to other alternative oils, with similar functional properties, modifies LDL cholesterol (LDLc) and other risk factors and biomarkers of CHD. A triple-blind, crossover, randomized controlled trial was conducted in humans (n = 60) with four highly-controlled diets containing (1) HOSBO, (2) 80:20 blend of HOSBO and fully hydrogenated soybean oil (HOSBO+FHSBO), (3) soybean oil (SBO), and (4) 50:50 blend of palm oil and palm kernel oil (PO + PKO). Before and after 29 days of feeding, lipids/lipoproteins, blood pressure, body composition, and markers of inflammation, oxidation, and hemostasis were measured. LDLc, apolipoprotein B (apoB), NonHDL-cholesterol (HDLc), ratios of total cholesterol (TC)-to-HDLc and LDLc-to-HDL cholesterol, and LDL particle number and small LDL particles concentration were lower after HOSBO and HOSBO+FHSBO compared to PO (specific comparisons p < 0.05). Other than TC:HDL, there were no differences in lipid/lipoprotein markers when comparing HOSBO+FHSBO with HOSBO. LDLc and apoB were higher after HOSBO compared to SBO (p < 0.05). PO + PKO increased HDLc (p < 0.001) and apolipoprotein AI (p < 0.03) compared to HOSBO and HOSBO+FHSBO. With the exception of lipid hydroperoxides, dietary treatments did not affect other CHD markers. HOSBO, and blends thereof, is a PHO replacement that results in more favorable lipid/lipoprotein profiles compared to PO + PKO (an alternative fat with similar functional properties).  相似文献   

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