Oil Swelling Research Articles

Functional properties and bioactive compounds of pigmented brown rice flour

This study aimed to investigate physicochemical and functional properties as well as bioactive compounds from Thai pigmented brown rice flours from four varieties of indigenous kinds of rice in Thailand, namely Hom mali (HR), Red hom mali (RHR), Riceberry (RBR) and Homnil (HNR). The results showed that all Thai pigmented brown rice flours contained high contents of carbohydrate, protein, vitamins and minerals. The highest amylose content was present in RHR. All Thai pigmented brown rice flours have low RAG (rapid available glucose) and GI (glycemic index), especially RHR. The pasting properties were slightly altered when heated. The gelatinization temperature was high, but the enthalpy was non-significant. These flours have good water and oil absorption, swelling, solubility, emulsion, and foaming properties. In addition, these flours have a high syneresis during storage at low temperatures. The study of bioactive compounds demonstrated that all Thai pigmented brown rice flours contained significant total amount of total phenolic compounds, flavonoids, and antioxidant activities, especially in RHR. The morphology study revealed that all samples are in polyhedral shape and varied in sizes.

Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling

This paper investigates the extent to which alcohol-treated carbon dioxide (CO2 ), a mixture of alcohol and CO2 equilibrated at experimental pressure and temperature, can lead to greater interfacial tension reduction and greater oil swelling than can pure CO2 . Experimental measurements of interfacial tension and swelling behavior are made using a high-pressure, high-temperature visual cell at 70 °C. Two sets of fluid pairs are used: pure CO2 and oil, and alcohol-treated CO2 and oil. Two types of oil are used: a mixture of 35% hexane and 65% decane (C6 -C10 mixture), and pure decane (pure C10 ). Ethanol and methanol are used to prepare alcohol-treated CO2 . Numerical simulations are used to estimate a reduction in the minimum miscibility pressure when using alcohol-treated CO2 . Interfacial tension between alcohol-treated CO2 and oil is found to be 0.02 to 2.2 mN/m less than that between pure CO2 and oil. Simulation results suggest that alcohol-treated CO2 yields 0.2 to 1.2 MPa lower minimum miscibility pressure compared to pure CO2 . Alcohol-treated CO2 also is found to cause 6% to 43% more swelling of oil than does pure CO2 . Interfacial tension and swelling results suggest that alcohol-treated CO2 yields better miscibility with oil compared to pure CO2 . Cited as: Saira, Yin, H., Le-Hussain, F. Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling. Advances in Geo-Energy Research, 2021, 5(4): 407-421, doi: 10.46690/ager.2021.04.06

Fluid-Fluid Interactions Inducing Additional Oil Recovery during Low Salinity Water Injection in Inefficacious Presence of Clay Minerals

One the most promising Enhanced Oil Recovery (EOR) methods, Low salinity water injection (LSWI) has faced several critical challenges, of which understanding the underlying mechanism is still of utmost importance. Here, we combine traditional coreflood experiments with several analytical tools to gain an insight into the mechanism of additional oil recovery by LSWI. Two crude oil samples with contrasting propensities to form microdispersion were chosen for coreflood experiments in a clay-rich sandstone core. Microdispersion is a term denoting the spontaneous formation of separated water phases within the crude oil phase by surface-active materials such as asphaltenes and/or carboxylic acids contributing to additional oil recovery by wettability alteration and crude oil swelling. Investigating the reasons behind the different responses to tertiary LSWI, it appeared that clay is not a decisive factor for low salinity effect (LSE) as previously believed. Additionally, surface charge evaluations and ionic composition of effluents showed that electrical double layer expansion and multi-ion exchange (MIE) mechanisms are not primary contributors to LSE. Extensive investigation by FT-IR spectroscopy and water content measurements suggests the underlying mechanism associated with LSWI is microdispersion formation by acidic materials (i.e., carboxylic acids and/or carboxylic functional groups of asphaltenes). The performance of tertiary LSWI, in terms of additional oil recovery, agreed well with the propensities of crude oils toward microdispersion formation. Experimental findings obtained herein contribute to resolve uncertainties around the mechanism of LSWI and look at reservoir eligibility for use of this EOR method.

Effects of pretreatment, NaOH concentration, and extraction temperature on the cellulose from Lophatherum gracile Brongn

Lophatherum gracile Brongn. (LGB), a homology material of medicine and food, has plentiful cellulose. Aiming to investigate the physiochemical characteristic differences of LGB cellulose extracted by various pretreatment methods and extraction conditions, the effect of dry crushing and wet beating, and the alkaline solution concentration and temperature were compared. Results showed that the extracted cellulose after dry crushing pretreatment had higher purity and lower non-cellulosic components such as hemicellulose, lignin and ash than those obtained by wet beating pretreatment. Furthermore, the impurities were more thoroughly removed by the alkaline solution at high concentration and temperature. Structural characterization revealed that the cellulose obtained by wet beating pretreatment had more fibrillation and smaller particle size, while destroyed crystallinity resulting in bad thermal stability. The alkaline solution temperature had no effect on the morphology and particle size, but high alkaline solution temperature (90 °C) improved crystallinity and thermal stability. Furtherly, the cellulose II produced by at high alkaline solution concentration (18 wt%) exhibited denser surface, smaller particle size and higher thermal stability than the cellulose I extracted at low alkaline solution concentration (4 wt%). Especially, the crystallinity of cellulose II was higher than that of cellulose I with dry crushing pretreatment, while the cellulose obtained by wet beating displayed an opposite trend. Hydration properties indicated that the water holding capacity, oil binding capacity and swelling capacity of the cellulose pretreated by dry crushing were higher than those of the cellulose pretreated by wet beating, and the cellulose I exhibited higher hydration properties compared to the cellulose II, which may depend on its loose network structure. This study suggested that dry crushing pretreatment and high alkaline solution temperature could effectively improve functional properties of LGB cellulose I and II, which promoted its use in food applications.

A novel model for determination of apparent diffusion coefficient of gaseous solvent mixture-heavy oil system with consideration of swelling effect and density variation

A reliable estimation of the apparent diffusion coefficient (D) of gaseous solvent mixtures (GSMs) in heavy oil (HO) is necessary for the design of GSM-based recovery techniques. In this study, diffusion measurements of GSM-HO systems were carried out at various temperatures (25°C to 54.2°C) and pressures (5 to 10 MPa). Then, a novel mathematical model was proposed to describe the diffusion process of GSMs in HO considering the oil swelling effect and density variation. The oil swelling effect was described with a newly developed density model of GSM-HO systems. Finally, the developed model was solved via a numerical method to determine the D of GSMs in HO and the dynamic processes of HO swelling under varied temperature and pressure conditions. The results indicated that the D values at the measured temperatures and pressures ranged from 3.81-22.62×10−10 m2•s−1. The average D value of the GSMs increased with temperature and pressure. The GSM concentration in HO, the height of the GSM-HO interface, and the swelling velocity of HO rapidly increased at the early stage and then slowly increased over time. The maximum GSM concentration was observed at the GSM-HO interface.

Fabrication of ethylene-vinyl acetate copolymer/polyamide/modified sepiolite composite with improved physical properties via e-beam irradiation

The effects of silanized sepiolite (SP) and electron beam (e-beam) irradiation on the physico-mechanical properties of ethylene-vinyl acetate copolymer (EVA)/ternary polyamide (tPA) composites were studied. SP was silanized with vinyltriethoxysilane (VTES) to enhance the dispersion and compatibility of the inorganic filler into the EVA/tPA matrix. The crosslinking of EVA/tPA by e-beam irradiation was carried out ranging from 50 to 250 kGy. The prepared composite films were characterized for change in morphology, mechanical properties, crosslinking effect on crystallinity and swelling using various established analytical techniques. Experimental results indicated that tensile strength of irradiated composite EVA/tPA/m-SP5 (70/30/5) was 3 times higher than that of virgin composite film at an absorbed dose of 250 kGy. The storage modulus of EVA/tPA/m-SP5 (70/30/5) composite film was significantly increased with the increase of absorbed dose. However, melting and crystallization temperature of EVA/tPA composites slightly decreased with the increase of absorbed dose. Moreover, the modification of SP with VTES and irradiated composite films were subjected to oil swelling studies.

Determination of individual concentration-dependent diffusivity of binary gas-mixtures in reservoir-fluid systems

Diffusion is one of the main mass transfer principles associated with a gas injection process, e.g., vapor extraction (VAPEX) and cyclic solvent injection (CSI), to reduce the viscosity of heavy oil by dissolution of light gas(es). A few efforts have been made to estimate the diffusivity of each gas component of a binary gas-mixture in heavy oil as a constant, but no attempts have been made to determine individual diffusivity of each gas component in the binary gas-mixture as concentration-dependent. In this study, the concentration-dependent diffusivities of CO2 and C3H8 in a CO2/C3H8 mixture, which preferentially diffuses in a Lloydminster heavy oil, are evaluated implicitly as a power function of gas concentration, pressure, and temperature through the oil viscosity. The coefficient and exponent of such a power function for each gas are determined once the deviations between the measured and calculated values for oil swelling factors and composition of each gas dissolved in heavy oil at the completion of a dynamic volume analysis (DVA) test are minimized by applying the 1D time-dependent finite element method (FEM). Compared with the constant diffusivities for the same test, considering concentration-dependency of the dissolved gases reproduces the experimentally measured oil swelling factors and compositions at the end of the test with a significantly enhanced accuracy. Then, such obtained concentration-dependent diffusivities are extended to reproduce the experimentally measured swelling factors of a pressure-decay test performed with another CO2/C3H8 gas-mixture and the same heavy oil. From such an evaluation, it can be inferred that the coefficient and exponent of the diffusivity correlation associated with a binary gas-mixture are functions of pressure, temperature, feed gas composition, and test duration, respectively. This is because the coefficient and exponent for one gas component may be affected by the presence of the other as the latter alters the composition of heavy oil in which the former diffuses.

CO2 dissolution and convection in oil at realistic reservoir conditions: A visualization study

CO2 convective mixing has been extensively studied for CO2 dissolution in saline water but very limited with the presence of oil. The objective of this work was to visually study the supercritical CO2 (sCO2) dissolution and convective mixing into oil at realistic reservoir temperature and pressure conditions with and without the presence of porous media.A specially designed high-pressure 2D-cell was used to investigate the sCO2 mixing into oil phases. Schlieren imaging method was used as the visualization method. The experiments were carried out at 100 bar and 50 °C using n-octane, n-decane, and crude oil as the main oils. Porous media with different permeability was prepared using glass beads.Convective fingering was found to accelerate the mixing of CO2 with n-octane and n-decane. It was not possible to visualize the CO2 convective fingering in crude oil due to the low opacity of the oil phase. The CO2 dissolution into oil phases was quite instantaneous and fast without the presence of porous media. The swelling of oil was measured as 55%, 50% and 11% for n-decane, n-octane and crude oil respectively without the presence of porous media. Boundary effects were affecting the CO2 mixing due to the circular shape of the 2D-cell. Having a water layer below the oil layer tends to dampen the CO2 transport from the oil phase to the water phase. CO2 dissolution into oil saturated porous media was slower compared to that without the presence of porous media. The mixing of CO2 was faster at higher permeability than at lower permeability. Visualization of CO2 convective mixing/fingers inside oil-saturated porous media using a Hele-Shaw cell yet to be achieved experimentally.

Characterization of Blends of Virgin Nitrile Rubber and Compounded Nitrile Rubber Latex Waste Reclaimed with Urea: Part II - Physico-Mechanical Properties

Recycling of rubber waste materials in order to convert these to usable products is one of the main challenges in the rubber industry. Reclaiming of rubber waste and blending it with virgin rubber have increased during the past due to the growing concern on the environment and increase in the prices of synthetic rubbers. Hence, the aim of this study is to partially replace virgin nitrile rubber (NBR) with reclaimed compounded NBR latex waste to develop new rubber blends suitable for special applications. In this study, physico-mechanical properties, ageing performance and swelling behaviour of virgin NBR / reclaimed NBR blend vulcanizates were evaluated and compared with those of the control vulcanizate produced solely with virgin NBR. Results showed that replacement of 50% virgin NBR with reclaimed NBR retained 71-86% of tensile strength, elongation at break and resilience. Hardness and modulus of this blend vulcanizate increased by less than 18%, whereas abrasion volume loss and compression set increased by 27%. Ageing resistance is similar to that of the control vulcanizate. Interestingly, resistance to swelling in toluene and ASTM oil No.3 increased by 14% and 32%, respectively. Hence, the 50:50 virgin NBR / reclaimed NBR vulcanizate would be suitable for oil resistant applications.

Grafting of various acrylic monomers on to natural rubber: Effects of glutaraldehyde curing on mechanical and thermo-mechanical properties

Natural rubber (NR) grafted with different acrylic-monomers, namely butyl acrylate (BA), methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA), were prepared via redox polymerization. This aims to enhance the mechanical and thermal properties of pristine NR by using a novel curing system of glutaraldehye (GA). Grafting of acrylic-monomers onto NR molecular chains was clarified using ATR-FTIR and 1H-NMR. It was found that the grafted-NR vulcanizates effectively improved the mechanical properties. Here, NR-g-PBMA showed enhancement in moduli, tensile strength and elongation at break of approximately 100, 280, and 40 %, respectively, when compared to the one without modification. It was also observed that, all the grafted-NR vulcanizates exhibited an improved crosslinking. This was elucidated through the engine oil swelling and the TSSR (i.e. Temperature Scanning Stress Relaxation) measurements. The latter test was also first proposed for characterizing the grafted-NR in terms of mechanical and thermo-mechanical interpretations. The thermogram clearly exhibited that the thermal properties of NR were significantly improved after graft copolymerization owing to the presence of functional groups on the molecular chain which enhanced the intermolecular attraction of the grafted-NR molecules. It can be summarized that two possibilities of interaction were observed: (I) the chemical interaction of GA-Rubber through the CC bonds and through the active ester groups of grafted-NR molecules, and (II) the physical polar-polar interaction through the presence of carbonyl groups of grafted-NR molecules. Thus, the present work is found to be beneficial to the future applications of NR which requires high specific modulus and thermal stability at low strain in case of flexible actuators and sensors. Furthermore, the newly curing technique can be easily used to fabricate article at low temperature with greater ease of processing.

An Improved Correlation to Investigate the Effect of Chemical Additives on the Mobility Ratio of Two-Phase Flow

World energy demand continues to increase, as they evolve, and developing countries consume more energy to keep their rising factories going. A significant portion of the energy demand is supplied by fossil fuels, especially crude oil. Therefore, in order to satisfy the world's energy demand, oil reserves and oil production capability must be increased. This objective can be accomplished by enhancing the recovery efficiency of the existing generating or mature reservoirs through the application of increased oil recovery. The injection of fluids into oil reservoirs has the purpose of supplementing natural energy and is used in some cases to engage with the reservoir's rock/oil system, standardizing for oil recovery, such as lower interfacial stress, oil swelling, reduction of oil viscosity and adjustment of wettability. Subject to comprehensive studies, in heavy oil reservoirs, polymer injection is not dependent on large technological instruments, requiring only mixing and filtration equipment, except for those already used for traditional water injections. In addition, polymers are non-toxic and corrosive and can produce desirable mobility ratios. The implementation of this approach decreases the output ratio of water to oil, thus decreasing operating. In the present work, thirty-five data points from experimental work had been investigated to develop a new correlation for viscosity of water by using the suitable program. It was analyzed the influence of the polymer additives on the mobility ratio, temperature and concentration effect on mobility ratio, and viscosity altering with the additives have been investigated. The results of the correlation showed acceptable agreement between the observed and predicted viscosity values. As a contrast to the polymer additives approach, pure water was proposed.

An Improved Correlation to Investigate the Effect of Chemical Additives on the Mobility Ratio of Two-Phase Flow

World energy demand continues to increase, as they evolve, and developing countries consume more energy to keep their rising factories going. A significant portion of the energy demand is supplied by fossil fuels, especially crude oil. Therefore, in order to satisfy the world's energy demand, oil reserves and oil production capability must be increased. This objective can be accomplished by enhancing the recovery efficiency of the existing generating or mature reservoirs through the application of increased oil recovery. The injection of fluids into oil reservoirs has the purpose of supplementing natural energy and is used in some cases to engage with the reservoir's rock/oil system, standardizing for oil recovery, such as lower interfacial stress, oil swelling, reduction of oil viscosity and adjustment of wettability. Subject to comprehensive studies, in heavy oil reservoirs, polymer injection is not dependent on large technological instruments, requiring only mixing and filtration equipment, except for those already used for traditional water injections. In addition, polymers are non-toxic and corrosive and can produce desirable mobility ratios. The implementation of this approach decreases the output ratio of water to oil, thus decreasing operating. In the present work, thirty-five data points from experimental work had been investigated to develop a new correlation for viscosity of water by using the suitable program. It was analyzed the influence of the polymer additives on the mobility ratio, temperature and concentration effect on mobility ratio, and viscosity altering with the additives have been investigated. The results of the correlation showed acceptable agreement between the observed and predicted viscosity values. As a contrast to the polymer additives approach, pure water was proposed.

Fabrication of Bioplastic from Rice Straw

<p><strong>Abstract.</strong> Oil based plastics have been proven as severe pollutants for the environments as they required years to be degraded. Thus, bioplastics are very attractive as the solution of this problem as they easier to be degraded in soil. This work was aimed to fabricate bioplastics from rice straw, with addition of carboxymethyl cellulose (CMC) and glycerol. Prior to the bioplastic fabrication, cellulose was extracted from rice straw through digestion process using ethanol solution (50% w/w) and sodium hydroxide solution (8% w/w) as catalyst. Digestion process was held for 60 minutes at temperature of 120 <sup>o</sup>C. Bioplastics were produced by blending dried pulp, carboxymethyl cellulose, and glycerol. Five grams of dried cellulose was dissolved in 100 ml of water. The amount of CMC and glycerol added to the pulp solution were varied from 1 ml to 2 ml and 0.5 to 1.5 grams, respectively. Swelling test (both in water and oil) and biodegradability test were conducted to study the performance of the bioplastics. Results showed that bioplactic dissolved easily in water. During oil swelling test, it showed that higher glycerol content increases the oil proof characteristic of the bioplastic. Meanwhile, the CMC content has no impact during the oil swelling test. The best composition of the bioplastic was achieved with the CMC and glycerol contents of 1.382% (w/w) and 1,843% (w/w), respectively, with the lowest oil swelling test result of 55%. Biodegradability of the bioplactics were lower in higher CMC and glycerol contents. The best composition with maximum weight reduction of the bioplastics was achieved by the bioplastic with 0.469% (w/w) of CMC content and 0.939% (w/w) of glycerol.</p><p><strong>Keywords:</strong> Bioplastic, Rice Straw, CMC, Glycerol, Swelling, Biodegradability</p>

Compositional Modeling of Dimethyl Ether–CO2 Mixed Solvent for Enhanced Oil Recovery

Dimethyl ether (DME) is a compound first introduced by Shell as a chemical solvent for enhanced oil recovery (EOR). This study aims to investigate the efficiency of EOR using the minimum miscible pressure (MMP) and viscous gravity number when a mixed solvent of CO2 and DME is injected. Adding DME to the CO2 water-alternating-gas process reduces the MMP and viscous gravity number. Reduction in MMP results in miscible conditions at lower pressures, which has a favorable effect on oil swelling and viscosity reduction, leading to improved mobility of the oil. In addition, the viscous gravity number decreases, increasing the sweep efficiency by 26.6%. Numerical studies were conducted through a series of multi-phase, multi-component simulations. At a DME content of 25%, the MMP decreased by 30.1% and the viscous gravity number decreased by 66.4% compared with the injection of CO2 only. As a result, the maximum oil recovery rate increased by 31% with simultaneous injection of DME and CO2 compared with only using CO2.

The Effect of Carbonyl and Hydroxyl Compounds on Swelling Factor, Interfacial Tension, and Viscosity in CO2 Injection: A Case Study on Aromatic Oils

A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible injection, CO2 may also contribute to oil recovery improvement by immiscible injection through modifying several properties such as oil swelling, viscosity reduction, and the lowering of interfacial tension (IFT). Moreover, CO2 immiscible injection performance is also expected to be improved by adding some solvent. However, there are a lack of studies identifying the roles of solvent in assisting CO2 injection through observing those properties simultaneously. This paper explains the effects of CO2–carbonyl and CO2–hydroxyl compounds mixture injection on those properties, and also the minimum miscibility pressure (MMP) experimentally by using VIPS (refers to viscosity, interfacial tension, pressure–volume, and swelling) apparatus, which has a capability of measuring those properties simultaneously within a closed system. Higher swelling factor, lower viscosity, IFT and MMP are observed from a CO2–propanone/acetone mixture injection. The role of propanone and ethanol is more significant in Sample A1, which has higher molecular weight (MW) of C7+ and lower composition of C1–C4, than that in the other Sample A9. The solvents accelerate the ways in which CO2 dissolves and extracts oil, especially the extraction of the heavier component left in the swelling cell.

Antibacterial polysaccharide-based hydrogel dressing containing plant essential oil for burn wound healing.

BackgroundPolysaccharide-based hydrogels have been developed for many years to treat burn wounds. Essential oils extracted from aromatic plants generally exhibit superior biological activity, especially antibacterial properties. Studies have shown that antibacterial hydrogels mixed with essential oils have great potential for burn wound healing. This study aimed to develop an antibacterial polysaccharide-based hydrogel with essential oil for burn skin repair.MethodsEucalyptus essential oil (EEO), ginger essential oil (GEO) and cumin essential oil (CEO) were employed for the preparation of effective antibacterial hydrogels physically crosslinked by carboxymethyl chitosan (CMC) and carbomer 940 (CBM). Composite hydrogels were prepared and characterized using antimicrobial activity studies, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, gas chromatography-mass spectrometery, rheological analysis, viscosity, swelling, water loss rate and water vapor transmission rate studies. In addition, the biocompatibility of hydrogels was evaluated in vivo by cytotoxicity and cell migration assays and the burn healing ability of hydrogels was tested in vivo using burn-induced wounds in mice.ResultsThe different essential oils exhibited different mixing abilities with the hydrogel matrix (CMC and CBM), which caused varying levels of reduction in essential oil hydrogel viscosity, swelling and water vapor transmission. Among the developed hydrogels, the CBM/CMC/EEO hydrogel exhibited optimal antibacterial activities of 46.26 ± 2.22% and 63.05 ± 0.99% against Staphylococcus aureus and Escherichia coli, respectively, along with cell viability (>92.37%) and migration activity. Furthermore, the CBM/CMC/EEO hydrogel accelerated wound healing in mouse burn models by promoting the recovery of dermis and epidermis as observed using a hematoxylin–eosin and Masson’s trichrome staining assay. The findings from an enzyme-linked immunosorbent assay demonstrated that the CBM/CMC/EEO hydrogel could repair wounds through interleukin-6 and tumor necrosis factor-α downregulation and transforming growth factor-β, vascular endothelial growth factor (VEGF) and epidermal growth factor upregulation.ConclusionsThis study successfully prepared a porous CBM/CMC/EEO hydrogel with high antibacterial activity, favorable swelling, optimal rheological properties, superior water retention and water vapor transmission performance and a significant effect on skin repair in vitro and in vivo. The results indicate that the CBM/CMC/EEO hydrogel has the potential for use as a promising burn dressing material for skin burn repair.

Lubrication dynamics of swollen silicones to limit long term fouling and microbial biofilms.

Bacterial contamination and biofilm formation on medical devices remain a costly and serious healthcare problem. Silicone (polydimethylsiloxane, PDMS) elastomers are common biomaterials but are susceptible to bacterial surface contamination and biofilm growth. 'Self-lubricated' PDMS elastomers (iPDMS) have the potential to greatly reduce rates of cell attachment, biofilm formation and infection. Cross-linked PDMS elastomers immersed in PDMS oil swell to an equilibrium concentration to form a swollen network, and then form a surface liquid layer through syneresis. Herein we have measured the swelling and syneresis kinetics as a function of time, viscosity (1.5 to 10 cSt), and cross-linking density to optimize the surface lubricant layer formation, and resistance to biofouling. The lubricant layer thickness was measured in situ (optical profilometry and AFM) for flat and micro-textured surfaces, as a function of time and swelling ratio, to be in a range from 0.1 to 1 μm, and continuously increases with time. We show this continuous generation is likely due to a gradual, dynamic re-structuring of the elastomer network. Long term antifouling properties of (10 cSt) iPDMS were tested for Pseudomonas aeruginosa growth in a flow culture bioreactor, and after 30 d showed a 103 to 104 reduction of bacterial cell density for iPDMS compared to conventional PDMS elastomers. This long term performance and non-specific activity makes them highly suitable for biomedical devices, such as urinary catheters.

Synergic effects of dissolved carbon dioxide and an anionic surfactant synthesized from Rapeseed oil on interfacial tension (IFT) reduction, wettability alteration, and oil swelling in the process of chemical water injection into carbonate oil reservoirs

It is common to upgrade chemical enhanced oil recovery (CEOR) method by using two or more additives to simultaneously benefit from their mechanisms in EOR process. Chemical water engineering in combinational methods should be such that additives do not neutralize each other's effects and do not change EOR mechanisms. Dissolved carbon dioxide is considered as an additive in carbonated water injection process. Oil swelling is the most important mechanism of carbonated water injection. Besides, wettability of reservoir rock, especially carbonate rock, in this method shifts to hydrophilicity. Injection of carbonated water and injection of surfactant solution are two important methods of EOR. When dissolved carbon dioxide is used as an additive, in addition to EOR, a large amount of carbon dioxide is stored in underground reservoir. In other words, carbonated water injection method follows a process with economic and environmental goals. However, its effect on water and crude oil interfacial tension (IFT) is not significant. In this study, the technique of combining additives was investigated to solve this challenge, i.e. to strengthen the mechanism of reducing interfacial tension. An anionic surfactant synthesized from Rapeseed oil at lower concentrations than critical micelle concentration (CMC), CMC and above CMC in combination with enriched chemical water by dissolved carbon dioxide was used. The experiments of IFT, oil swelling and contact angle were performed for this purpose. Pressure, temperature and salinity effects as parameters affecting carbonated water performance were studied in the experiments. According to the findings, the combination of using the surfactant with carbonated water significantly reduces the IFT even at higher concentrations than CMC. At 80 °C and 2000 psi, the IFT of carbonated fluids at the surfactant concentrations of 0, 3500, 4500, and 5500 ppm were 10.927, 4.948, 3.596, and 1.503 mN/m, respectively. The contact angle increases at a lower concentration than CMC, decreases sharply at CMC and the intensity of the decreasing trend decreases at a higher concentration than CMC but it remains less than the contact angle at CMC. At 80 °C and 2000 psi, the contact angle values at the surfactant concentrations of 0, 3500, 4500 and 5500 ppm were 71.41°, 80.52°, 60.44° and 55.18°, respectively. Crude oil swelling rises at a lower concentration than CMC and CMC but decreases at a higher concentration than CMC as it has the highest value at CMC. At 80 °C and 2000 psi, increased oil swelling values at the surfactant concentrations of 0, 3500, 4500 and 5500 ppm were 10.10%, 15.41%, 15.62% and 14.52%, respectively.

In Situ Compatibilization of Polyamide 6/Carboxylated Acrylonitrile Butadiene Rubber Blends with Polyhedral Oligomeric Silsesquioxane

AbstractThe aim of the study is to prepare thermoplastic elastomer composites of polyamide (PA6) with carboxylated acrylonitrile butadiene rubber (XNBR), compatibilized with polyhedral oligomeric silsesquioxane with epoxy groups (POSS‐epoxy). The addition of POSS‐epoxy, particularly 3.5 phr, improved the specialty characteristics of the PA/XNBR thermoplastic‐elastomer blend. The PA/POSS/XNBR mainly showed a considerable improvement in the elastic torque. The in situ compatibilization is confirmed by density and oil swelling analyses. The structural property relationships of the vulcanized thermoplastic, measured by XRD, DSC and Raman spectroscopy, revealed there are changes in the chemical structure induced by the molecular interactions of PA‐POSS‐XNBR. The Raman spectra confirmed the presence of silane in the PA/XNBR blend. The crystallinity results obtained from the XRD spectra of the PA/XNBR blend are modified by the POSS‐epoxy, corroborating the oil swelling results.

Recovery of viscous and heavy oil by CO2-saturated brine

Fast economic growth in Oman coupled with its climatic conditions have led to an energy-intensive lifestyle that has resulted in high levels of carbon dioxide (CO2) emissions. The injection of CO2 produced by cement plants into oil reservoirs combined with carbon capture is seen as an option to reduce CO2 in the air in order to curb climate change. The potential of CO2-saturated brine to recover oil is investigated using two samples of viscous oil (13 and 21 cP) and one sample of heavy oil (1471 cP) from Oman in water flooding experiments followed by CO2-saturated brine injection at 25 °C and 3.45 MPa. CO2 solubility in oil and brine, changes of their viscosity and density, oil swelling and other parameters are investigated.Irrespective of early water breakthrough, the greatest incremental recovery of 25.6% after injection of CO2-saturated brine through oil saturated core is obtained for heavy oil, as compared to 8.2% and 15% for viscous oils. Higher recovery from heavy oil sample is explained by the greater viscosity reduction in addition to the density reduction of CO2-saturated oil that is similar for all three types of oil of about 50% on average. The greatest reduction of oil viscosity of 87% is obtained for the heavy oil and 59% on average for viscous oil samples. Thus, different mechanisms contribute more into the oil recovery: density reduction due to oil swelling for viscose oil and viscosity reduction for heavy oil.The injection of CO2-saturated brine demonstrates a great potential in addressing both issues, curbing of climate change and energy supply by enhanced recovery of viscous and heavy oil.