Increase In Apparent Viscosity Research Articles

An experimental study of foam-oil interactions for nonionic-based binary surfactant systems under high salinity conditions

A key factor affecting foam stability is the interaction of foam with oil in the reservoir. This work investigates how different types of oil influence the stability of foams generated with binary surfactant systems under a high salinity condition. Foam was generated with binary surfactant systems, one composed of a zwitterionic and a nonionic surfactant, and the other composed of an anionic and a nonionic surfactant. Our results showed that the binary surfactant foams investigated are more tolerant under high salinity conditions and in the presence of oil. This was visually observed in our microscopic analysis and was further attributed to an increase in apparent viscosity achieved with binary surfactant systems, compared to single surfactant foams. To understand the influence of oil on foam stability, we performed a mechanistic study to investigate how these oils interact with foams generated with binary surfactants, focusing on their applicability under high salinity conditions. The generation and stability of foam are linked to the ability of the surfactant system to solubilize oil molecules. Oil droplets that solubilize in the micelles appear to destabilize the foam. However, oils with higher molecular weights are too large to be solubilized in the micelles, hence the molecules will have less ability to be transported out of the foam, so oil seems to stabilize the foam. Finally, we conducted a multivariate analysis to identify the parameters that influenced foam stability in different oil types, using the experimental data from our work. The results showed that the oil molecular weight, interfacial tension between the foaming liquid and the oil, and the spreading coefficient are the most important variables for explaining the variation in the data. By performing a partial least square regression, a linear model was developed based on these most important variables, which can be used to predict foam stability for subsequent experiments under the same conditions as our work.

Microwave‐modified xanthan gum: Alterations in steady and dynamic rheological behaviors

AbstractIn this study, microwave modification of xanthan gum (XG) powder under various power and time settings was aimed at achieving diversity for different applications requiring different flow behaviors. Microwave treatment for 6 min at various powers showed no noticeable effect on the properties of XG. The apparent viscosity, consistency coefficient and viscoelastic properties (G′–G″) increased as powders were subjected to microwave treatment for up to 8 min and the highest increase was observed in XGs with 720 W application. The increasing power to 1200 W resulted in a decrease in consistency at 8 min. At all levels of power, a prolonged microwave treatment (10 min) resulted in the degradation of the molecules, leading to a decrease in the mentioned rheological properties of XG. The values for intercepts (K′ and K″) began to increase at 960 W‐6 min, with the largest increase occurring at 720 W‐8 min. Fourier transform infrared (FTIR) analysis revealed that the primary structure and repeated units were not negatively impacted by the use of microwave treatment. Therefore, with adjustable modification, microwaves may be employed to produce xanthan gum with a high economic value that is suitable for a variety of applications, while maintaining the gum's color properties.Practical applicationsOur research demonstrated that the use of microwave technology as a non‐thermal physical process to modify xanthan gum powder without dissolving it in water is a highly effective technique. This approach enables the flow characteristics of xanthan gum to be conveniently modified, regardless of its concentration, and increases its economic value by diversifying its techno‐functional properties. The increase in apparent viscosity and viscoelastic properties by increasing the interaction of polymer molecules or the adaptation of xanthan gum to different purposes by polymer degradation can be adjusted depending on the power and time of the microwave.

Effect of Microplastic Particles on the Rheological Properties of Human Saliva and Mucus.

Pollution by plastic microparticles is rising rapidly. One avenue of human exposure to nanoparticles is through inhalation. The main source of microplastics in indoor environments, leading to unintended inhalation, is synthetic fabric used in clothing. Other sources include curtains, carpets, furniture, wall paints, and floor finishes. Occupational exposure is particularly significant in waste management and recycling operations, during exposure to high heat, during high-energy treatment of polymer composites, and during 3D printing. In outdoor environments, exposure can happen through breathing in contaminated aerosols from ocean waves or airborne particles from dried wastewater treatments. Airborne particles affect human health in various ways, including via direct interactions with the epithelium and its mucus layer after deposition in the mouth and respiratory system. Exposure due to the ingestion of microplastics present in various environmental compartments may occur either directly or indirectly via the food chain or drinking water. This study aimed to determine the effects of plastic microparticles on the rheology of mucus and saliva, and, thus, their functioning. The experiments used artificial mucus, saliva, and plastic nanoparticles (namely, PS-polystyrene and PE-polyethylene). The rheological properties of saliva and mucus were determined via the use of an oscillatory rheometer at various temperatures (namely, 36.6 °C and 40 °C, which correspond to healthy and ill humans). The results were compared with those obtained for pure saliva and mucus. An increase in apparent viscosity was observed for saliva, which is behavior typical of for solid particle suspensions in liquids. In contrast, for mucus, the effect was the opposite. The influence of the presence of the particles on the parameters of the constitutive viscosity equations was studied. Plastic micro- and nanoparticles in the saliva and mucus may interfere with their physiological functions.

Enhanced O/W emulsion stability and betanin protection using yeast protein and chitooligosaccharide: Comparative insights from complex coacervation and layer-by-layer methods

Emulsions play a pivotal role in food and related industries, yet oil-in-water (O/W) emulsions, a staple emulsion, are plagued by instability issues like aggregation, flocculation, and gravitational separation during storage. Stabilizing these emulsions has often involved the use of proteins or polysaccharides. Within this context, this research delves into comparing two distinctive stabilization strategies for emulsions. The yeast protein (YP), chitooligosaccharide (COS), and betanin were employed to formulate a complexation emulsion (CE) using a complex coacervation method, and a bilayer emulsion (BE) through a layer-by-layer method. The effects of these divergent methods on the emulsion's physicochemical properties, microscopic structure, and the stability of betanin was assessed. The findings indicate that the yeast protein-chitooligosaccharide-betanin (YCB) emulsion prepared using the layer-by-layer method demonstrated the smallest droplet size and the greatest absolute ζ-potential. After a storage period of seven days, this emulsion showed the lowest emulsification index, indicating excellent storage stability. In tandem, an increase in apparent viscosity was observed, with the emulsion exhibiting weak gel-like behavior. The incorporation of betanin has improved the physical stability of emulsions, and concurrently, the emulsion presented an improved storage stability of betanin. These results provide insightful perspectives for the development of emulsions based on bilayer interfaces, contributing to the expansion of novel fungal protein applications in the fields of emulsion technology, food processing, and the stabilization of bioactive molecules.

Soy protein isolate-guar gum-goose liver oil O/W Pickering emulsions that remain stable under accelerated oxidation at high temperatures.

Goose liver oil (GLO) is a solid-liquid mixture, rich in polyunsaturated fatty acids and high in nutritional value, but poor in fluidity and easily oxidized. Therefore, oil-in-water (O/W) Pickering emulsions of three polysaccharides and soy protein isolate (SPI) with GLO were prepared to improve the stability of it. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier-transform infrared spectroscopy, and zeta potential revealed that the SPI and complexes with konjac glucomannan, pectin, and guar gum (GG) ranged from 17 to 75 kDa, with the site of action being the -OH stretch and the amide group, and bound by hydrogen bonding. Adding konjac glucomannan and GG significantly increased the water contact angle of the SPI to 74.1° and 59.0°, respectively. Therefore, the protein-polysaccharide complexes could enhance the emulsion stability. In addition, the O/W Pickering emulsions with GLO had near-Newtonian fluid rheological properties with a significant increase in apparent viscosity and viscoelasticity, forming a dual network structure consisting of a ductile and flexible protein network and a rigid and brittle polysaccharide network. The microstructure observation indicated that the O/W emulsions were spherical and homogeneous. The highest emulsification activity was observed for the SPI-GG-GLO emulsions, without significant delamination or flocculation and high oxidative stability after 7 days in storage. These results demonstrate that the construction of SPI-GG-GLO O/W Pickering emulsions can stabilize GLO even at high temperatures that promote oxidation. © 2023 Society of Chemical Industry.

Physicochemical and Functional Properties of Thermal-Induced Polymerized Goat Milk Whey Protein.

Goat milk whey protein products are a hard-to-source commodity. Whey protein concentrate was directly prepared from fresh goat milk. The effects of the heating temperature (69-78 °C), time (15-30 min), and pH (7.5-7.9) on the physicochemical and functional properties of the goat milk whey protein were investigated. The results showed that the particle size of the samples significantly increased (p < 0.05) after heat treatment. The zeta potential of polymerized goat milk whey protein (PGWP) was lower than that of native goat milk whey protein. The content of the free sulfhydryl groups of PGWP decreased with increasing heating temperature and time, while an increase in surface hydrophobicity and apparent viscosity of PGWP were observed after heat treatment. Fourier Transform Infrared Spectroscopy analysis indicated that heat treatment and pH had considerable impacts on the secondary structure of goat milk whey protein. Transmission electron microscope images revealed that heat induced the formation of a large and uniform protein network. Additionally, the changes in the physicochemical and structural properties contributed to the improvement of the emulsifying and foaming properties of goat milk whey protein after heat treatment. The results may provide a theoretical basis for the applications of polymerized goat milk whey protein in related products.

Impacts of cold-extrusion whey protein isolate synergized with inulin on physicochemical characteristics of fermented milk

Impacts of extruded whey protein isolate-inulin (EWPI-I) complexes with different inulin ratios (5%, 10%, and 15%) on the textural, sensory, and rheological characteristics of fermented milk were investigated in this work. The addition of inulin to both EWPI-I and WPI-I complexes in ratios of 0–15% resulted in a gradual increase in apparent viscosity, water holding capacity (WHC), viable counts, and consistency index K of fermented milk. However, these properties decreased during the storage period (P < 0.05). Rheology analysis revealed that the consistency index K of EWPI-I fermented milk was higher than that of WPI-I fermented milk within 14 days of storage due to the formation of high molecular WPI polymers induced by extrusion. Principal component analysis (PCA) showed that EWPI-15%I (inulin ratios of 15%) fermented milk exhibited the best characteristics among all fermented samples. Furthermore, hardness, adhesion, chewiness and WHC of EWPI-15%I fermented milk were 261.13%, 298.31%, 480.40% and 38.24% higher than those of untreated fermented milk. It was observed that on the first day of storage, the viability of S. thermophilus and L. bulgaricus in EWPI-15%I fermented milk increased by 2.99% and 3.14%, respectively, compared to untreated samples. The proliferation of S. thermophilus and L. bulgaricus was found to be more conducive with combination of EWPI and inulin. Therefore, EWPI-I complex could remarkably improve water holding capacity and rheological properties of fermented milk, which will be applied for developing fermented dairy products with high quality characteristics.

Physicochemical, Rheological, and Nutritional Quality of Artisanal Fermented Milk Beverages with Cupuassu (Theobroma grandiflorum) Pulp and Flour.

The use of fruits and their by-products in food has dramatically impacted the food industry due to the nutritional benefits and the technological and sensory effects of food matrices. Therefore, this research aimed to evaluate the effects of adding cupuassu (Theobroma grandiflorum) pulp and flour on fermented milk beverages' physicochemical, microbial, and sensory properties during refrigerated storage (0, 7, 14, 21, and 28 days). Twelve formulations were realized with different percentages of cupuassu pulp (0, 5, 7.5, and 10% w/v) and flour (0, 1.5, and 3% w/v). The treatments with 3% cupuassu flour presented the highest percentages of protein, fat, fiber, and carbohydrates, compared with the samples containing pulp. On the other hand, the addition of pulp increased water retention capacity and color parameters (L*, a*, b*, and C*) and decreased pH and syneresis on day 0 of storage. During storage, the samples with pulp showed increases in pH values, consistency index, and apparent viscosity. In comparison, cupuassu flour addition decreased syneresis values and increased L* and b* during storage, as did pulp. In addition, sample HPHF (10% pulp and 3% cupuassu flour), based on just-about-right, penalty, and check-all-that-apply analyses, improved some sensory attributes of the fermented milk beverage, such as brown color, acid taste, bitter taste, cupuassu flavor, and firm texture. It can be concluded that cupuassu pulp and flour addition improves the physicochemical and sensory quality of fermented milk beverages and can provide nutritional value to the product.

Enhancing solid-like characteristics of porcine plasma protein-carrageenan-based high internal phase emulsion: As solid fat alternative of loading curcumin

This study explored the feasibility of a novel solid-like fat stabilized by porcine plasma protein (PPP) and carrageenan (CG) coupling emulsifier as curcumin delivery vehicle. The combination of 2.0% (w/v) PPP and 0.3% (w/v) CG successfully stabilized the oil of 80% (v/v) volume fraction at solid-like state, and the increasing of oil phase led to the increase in droplet size, storage modulus (G′) and apparent viscosity. Compared with free oil, oxidation of PPP-CG-stabilized solid-like fat could be significantly inhibited. The results from in vitro simulated digestion showed that the release rate of free fatty acids and bioaccessibility of curcumin in the solid-like fat were significantly higher than those in free oil, and curcumin was almost not released in simulated gastric fluid, but mainly released in simulated intestinal fluid. Therefore, PPP-CG-stabilized solid-like fat could be used as an effective nutrient delivery vehicle for food and pharmaceuticals, and the work provided some new insights into the structure design of functional food.

Importance of Temperature-Dependent Non-Newtonian Fluid in Conventional Thermal Processing

Abstract Computational fluid dynamics (CFD) simulation provides full-field variables, enabling a better understanding of flow physics and associated heat transfer. However, assumptions involved in CFD simulation should not affect flow and temperature fields and their correspondence to practical situations. Therefore, the present study analyzed the importance of temperature-dependent fluid properties in a sealed container during thermal treatment. We compared the thermal behavior trends of temperature-dependent fluid properties with those obtained from constant properties for two carboxyl methyl cellulose (CMC) solution concentrations. The results show that natural convection occurs earlier in the temperature-dependent fluid properties, which leads to attaining a desired level of sterility within a shorter time than the constant properties of the fluid. The variations in the viscosity with the shear rate and temperature played essential roles in affecting thermal behavior. So, results indicate that temperature-dependent non-Newtonian fluid must be considered to avoid miscalculating heating time in conventional thermal treatment. Besides, the thermal trends of both cases approach pure conduction when CMC solutions’ apparent viscosity increases.

Rheology of oil-based nitrogen foam at shallow reservoir conditions: Experiment and evaluation

Exhibiting as a combination of viscous, elastic, and plastic behavior, rheology is a branch of physics and is majorly concerned with continuum mechanics for flow characterizations, particularly non-Newtonian flow like foam. However, most existing studies of foam rheology are primarily focused on water-based foam, while oil-based foam rheology lacks adequate understanding, plus few comprehensive experimental analyses have been done. This study, for the first time, investigates the rheological behavior of oil-based nitrogen foam with full foam quality and shallow reservoir conditions through a newly-designed visualized capillary rheometer. Basically, the effects of foam quality and shear rate on foam morphology and apparent viscosity were elucidated, and the foam rheology at different temperatures and pressures was evaluated. More specifically, with increasing shear rate, the apparent viscosity of nitrogen foam decreases in a concave-down parabola pattern. With the foam quality of 86 %, the apparent viscosity of the foam flow is found to reach its maximum value, 58.4 mPa·s, at the flow rate of 4 mL/min, temperature of 25 °C and pressure of 5 MPa. The foam flow gradually becomes uniform and dense and the apparent viscosity elevates with increasing foam quality up to 86 %. After that, the foam flow tends to be slug flow and its stability becomes worse with linearly-decreasing apparent viscosity. With increasing pressure, the apparent viscosity and consistency coefficient increase, which result in the increase of rheological index and decrease of non-Newtonian property. The temperature effects on the foam flow are absolutely opposite but stronger in comparison to pressure effects as aforementioned. In addition, the rheological equations of nitrogen foam are determined by fitting the consistency coefficient and rheological index with foam quality. Overall, thorough investigations of the rheology of oil-based nitrogen foam would be of great importance for foam theory and practice.

Influence of rheology in the filtration of leach slurry generated by alkaline pressure leaching of a limestone ore

The Nuclear Power Plant, which uses uranium as a fuel, is considered as a clean source of energy with low carbon footprint and less environmental damage. In processing the uranium ore, the filtration of alkaline leach slurry generated by oxidative pressure leaching is a challenge due to very fine grind size coupled with high total dissolved solutes (TDS). The present study aimed at improving and understanding the filtration of the leach slurry with the help of slurry rheology. The effect of solid concentration, temperature, particle size, and dosages of dewatering aids on the rheological behavior of the slurry and the filtration performance was investigated. The slurry rheology was delineated by the Herschel–Bulkley model, temperature effects were incorporated using the Arrhenius type model, and particle size distribution (PSD) was represented by the Rosin–Rammler PSD model. The dosages of dewatering aids were compared using rheological parameters. It was found that the filtration rate decreases as solid concentration increases (10 to 75%, w/w) due to an increase in the shear stress (9.93 to 757 Pa at 1400 s−1). The leach slurry showed shear thickening at ≤ 60% solids (w/w) and shear thinning at ≥ 70% solids. The maximum solid packing volume fraction was found to be 0.59 and 0.54 at 1300 and 441 s−1, respectively. Increase in filtration rate was observed at elevated temperatures as the apparent viscosity (at 1300 s−1) decreased from 0.0195 Pa.s at 20 °C to 0.0135 Pa.s at 70 °C. The fluid flow activation energy was determined to be 5.5 and 7.1 kJ/mol at 1110 s−1 for 50 and 73% solid concentration (w/w), respectively. When the particle size (d90) was changed from 66 to 42 µm, a decrease in filtration rate was observed due to an increase in apparent viscosity from 0.0120 to 0.0163 Pa.s at 1400 s−1. The high molecular weight polyacrylamide based non-ionic synthetic flocculant N 100 and non-ionic biodegradable polysaccharide surfactant guar gum formed flocs through the bridging mechanism and gave best flocculation results, and therefore selected. The present work helps the researchers in better understanding and improving the filtration process of ore slurries.

Preparation of high concentration coal water slurry with good fluidity based on preferentially modified ultrafine particle under three-peak grading

ABSTRACT Coal water slurry (CWS) with high solid content and good fluidity is critical to efficient gasification and pipeline transport. The large number of oxygen-containing functional groups on the surface of the coal particles allow a large amount of water to be bound to the surface, resulting in a decrease in free water and an increase in apparent viscosity. Surface modification using the suspension of the second fluid and the second particle can reduce the viscosity and improve fluidity, since the oil film layer on the surface of the particles can cover the oxygen-containing functional groups and improve the hydrophobicity. Three-peak grading reduces viscosity by increasing the accumulation efficiency of particles. Preferentially modified the ultrafine particles under three-peak grading was found to result in the greatest decrease in viscosity and the most significant increase in fluidity. It not only helps to improve the accumulation efficiency, but the elastic oil film layer on the surface like an “air cushion” to reduce the frictional resistance between the particles, which effectively improved the fluidity of CWS. Ultimately, preferentially modified ultrafine particles under three-peak grading increased the slurry concentration from 62.0 wt% to 69.0 wt%, and it still had good fluidity with fluidity grade A + .

Unsteady-state CO2 foam injection for increasing enhanced oil recovery and carbon storage potential

The efficiency of CO2 injection for enhanced oil recovery and carbon storage is limited by severe viscosity and density differences between CO2 and reservoir fluids and reservoir heterogeneity. In-situ generation of CO2 foam can improve the mobility ratio to increase oil displacement and CO2 storage capacity in geological formations. The aim of this work was to investigate the ability of CO2 foam to increase oil production and associated CO2 storage potential, compared to other CO2 injection methods, in experiments that deploy field-scale injection strategies. Additionally, the effect of oil on CO2 foam generation and stability was investigated. Three different injection strategies were implemented in the CO2 enhanced oil recovery and associated CO2 storage experiments: pure CO2 injection, water-alternating-gas and surfactant-alternating-gas. Foam generation during surfactantalternating-gas experiments showed reduced CO2 mobility compared to water-alternatinggas and pure CO2 injections indicated by the increase in apparent viscosity. CO2 foam increased oil recovery by 50% compared to pure CO2 injection and 25% compared to water-alternating-gas. In addition, CO2 storage capacity increased from 12% during pure CO2 injection up to 70% during surfactant-alternating-gas injections. Experiments performed at high oil saturations revealed a delay in foam generation until a critical oil saturation of 30% was reached. Oil/water emulsions in addition to CO2 foam generation contributed to CO2 mobility reduction resulting in increased CO2 storage capacity with foam. Cited as: Sæle, A., Graue, A., Alcorn, Z. P. Unsteady-state CO2 foam injection for increasing enhanced oil recovery and carbon storage potential. Advances in Geo-Energy Research, 2022, 6(6): 472-481. https://doi.org/10.46690/ager.2022.06.04

The role of zinc sulphate as a retarder for alkali activated binders and its influence on the rheological, setting and mechanical behaviour

Alkali activated materials are alternative cementitious materials that have demonstrated good mechanical and durability properties. However, these materials exhibit quick setting and poor workable times. To address this issue, in this study, zinc sulphate was used as a retarder to alkali activated ground granulated blast furnace slag and fly ash (AASFA) mixtures. The rheological, setting and mechanical behaviour of AASFA mixtures with different molar modulus, proportion of fly ash and dosage of ZnSO4·7H2O were investigated. Delay in setting time, increase in workable time, reduction in yield stress and apparent viscosity, and absence or minimal secondary increase in storage modulus of AASFA mixtures were observed with an increase in the dosage of ZnSO4·7H2O from 0 to 3%. The compressive strength of AASFA mixtures at early ages decreased with an increase in the content of zinc sulphate and attained more than 80% of the control strength at 28 days and above.

Rat Brain Global Ischemia-Induced Diffusion Changes Revisited: Biophysical Modeling of the Water and NAA MR "Diffusion Signal".

To assess changes in intracellular diffusion as a mechanism for the reduction in water ADC that accompanies brain injury. Using NAA as a marker of neuronal cytoplasmic diffusion, NAA diffusion was measured before and after global ischemia (immediately postmortem) in the female Sprague-Dawley rat. Diffusion-weighted PRESS spectra, with diffusion encoding in a single direction, were acquired from large voxels of rat brain gray matter in vivo and postischemia employing either pairs of pulsed half-sine-shaped gradients (in vivo and postischemia, bmax = 19 ms/μm2 ) or sinusoidal oscillating gradients (in vivo only) with frequencies of 99.2-250 Hz. A 2D randomly oriented cylinder (neurite) model gave estimates of longitudinal and transverse diffusivities (DL and DT , respectively). In this model, DL represents the "free" diffusivity of NAA, whereas DT reflects highly restricted diffusion. Using oscillating gradients, the frequency dependence of DT [DT (ω)] gave estimates of the cylinder (axon/dendrite) radius. A 10% decrease in DL,NAA followed global ischemia, dropping from 0.391 ± 0.012μm2 /ms to 0.350 ± 0.009μm2 /ms. Modeling DT,NAA (ω) provided an estimate of the neurite radius of 1.0± 0.6μm. Whereas the increase in apparent intraneuronal viscosity suggested by changes in DL,NAA may contribute to the overall reduction in water ADC associated with brain injury, it is not sufficient to be the sole explanation. Estimates of neurite radius based on DT (ω) were consistent with literature values.

Tailoring the Textural Characteristics of Fat-Free Fermented Concentrated Milk-Protein Based Microgel Dispersions by Way of Upstream, Downstream and Post-Production Thermal Inputs.

There is a growing demand for new strategies to tailor the texture of fat-free fermented concentrated milk products, also referred to as milk protein-based (MPb) microgel dispersions. Methods should be easy to incorporate into the production scheme, offer labelling without added components and be cost-efficient. Thermal treatments are traditionally used upstream (milk heating) and downstream (pre-concentration heating) in the production of these dispersions, though there is little knowledge as to the effects that combinations of different thermal input levels have on final texture. Therefore, this study investigated combinations of thermal input at different intensities and steps in the production scheme at the pilot scale and the relationships with texture. We demonstrated that increasing the intensity of upstream milk heat treatment, in combination with downstream pre-concentration heating, increases gel firmness and apparent viscosity. Downstream pre-concentration heating produces final fat-free fermented concentrated MPb microgel particles that are resistant to post-heating aggregation. On the other hand, omission of downstream pre-concentration heating results in smaller particles that are sensitive to post-heating aggregation. Furthermore, gel firmness and apparent viscosity increase with post-heating. Consequently, combining different levels of thermal inputs upstream, downstream (pre-concentration) and post-production, can produce fat-free fermented concentrated MPb microgel dispersions with a range of different textures.

Intrinsically Viscoelastic Supramolecular Conjugated Polymer toward Suppressing Coffee-Ring Effect

Intrinsically Viscoelastic Supramolecular Conjugated Polymer toward Suppressing Coffee-Ring Effect

Particle image velocimetry for investigating the effect of liquid rheology on flow field of liquid–solid hydrocyclone

ABSTRACT Liquid rheology affects the separation performance of hydrocyclones. Sewage entering a de-foulant hydrocyclone with a reflux ejector (DFHRE) exhibits different rheological properties based on the source. In this study, particle image velocimetry is used to investigate the effect of liquid rheology on the overflow–suck–underflow effect of the DFHRE. Results show that the effects of the rheological properties, liquid concentration, and inlet velocity on the flow field are primarily reflected inside the locus of the zero vertical velocity at the cone section of the DFHRE. In addition, the overflow–suck–underflow effect becomes less prominent as the apparent viscosity increases. An increase in glycerin (Newtonian) concentration increases the total pressure drop, unlike an increase in polyacrylamide aqueous solution (PAM, non-Newtonian). Increasing the inlet velocity can enhance the overflow–suck–underflow effect in PAM owing to the lower drag force. This implies that the DFHRE can achieve an overflow–suck–underflow effect on fluids with a lower drag force and enhance the separation performance.

Stable foam systems for improving oil recovery under high-temperature and high-salt reservoir conditions

Foams have high apparent viscosity when flowing in porous media, therefore foam flooding could significantly improve unfavorable mobility ratios, increase sweep efficiency, and enhance oil recovery. However, the applications of foam flooding in high-temperature and high-salt reservoirs are seriously restricted as foam systems often have inferior foamability and stability in these reservoirs. In this study, to improve foam flooding effectiveness in high-temperature and high-salt reservoirs, novel foam systems with excellent stability and plugging capacity are developed by combining surfactants, additives, and polymers. The performance of bulk foam, physical properties of the solutions, and properties of foam systems in core-flow experiments are investigated to determine the synergistic effects among the components of the foam systems and their foamability and plugging effect in cores. In foam systems with sodium alcohol ether sulfate (AES) and dodecylhydroxypropyl sulfobetaine (DHSB) as surfactants, and dodecanol as additive, the combination of the components makes surface tension decreased and surface dilatational modulus increased, therefore the foamability and stability of the systems are improved. The results of core-flow experiments under high-temperature and high-salt conditions show that these combined systems require low injection rate for foam generation in reservoirs, which is beneficial for foam regeneration in reservoirs. Moreover, to further improve the foam performance, a hydrophobically associating water-soluble polymer (HAWP) is employed. The interactions between HAWP and the surfactants reduce the critical association concentration of HAWP, and result in the increase of solution apparent viscosity and foam stability. The results of core-flow experiments under high-temperature and high-salt conditions show that polymer-enhanced foam systems could significantly increase the sealing pressure, widen the sealing permeability range, and deal with the gas-channeling problem of foam flooding. These foam systems could provide a potential technical pathway for improving the effectiveness of foam flooding in high-temperature and high-salt reservoirs.