Foam Drainage Research Articles

Factors influencing the stability of natural gas foam prepared by alkyl polyglycosides and its decay rules

By using alkyl polyglycoside (APG) as foaming agent and natural gas as gas phase, the natural gas foam system was prepared, and the influence of alkyl chain length, metal cation valence and concentration, and polymer types on the foam stability was studied. By completely observing the volume and time required for the foam drainage liquid under different conditions, a foam drainage kinetics model was established. The drainage rate constant, the maximum drainage rate and its occurrence time during the foam drainage process can be acquired by derivation of the fitting function. The Arrhenius equation was adopted to fit the drainage rate constant at different temperature, and the drainage activation energy is obtained. The drainage process of foam was further analyzed from the perspective of kinetics. Moreover, the changes in geometric geometrics such as bubble number, particle size distribution frequency and the average diameter of the bubble in the decay process under different conditions was counted. According to the mathematical relationship between the average diameter and time, the Ostwald ripening rate and gas molecule diffusion constant are calculated. Finally, through the investigation of the interface properties and the micromorphology of the solution, the reasons for the above rules are explained. The research shows that: 1) the increase of the alkyl chain length of APG within a certain range (8–10.9) is beneficial to the improvement of the foam stability, and the continuous increase of chain length (10.9–12) is adverse to the foam stability, 2) the increase in the salinity of prepared water and the metal ions valence enhances the foam stability to a certain extent, 3) DG is more stable to APG foam than XG and KYPAM-6s. This study enriches the stability rules of APG foam with natural gas as the gas phase under different conditions, and provides ideas and methods for quantitatively analyzing the foam decay process from the perspectives of kinetics and statistics, which provides theoretical support for the application of natural gas foam in enhance oil recovery.

The Effect of Inclination on the Stability of Foam Systems in Drilling and Well Operations

SummaryTo minimize fluid loss and the associated formation damage, foam is a preferred fluid to perform cleanout operations and reestablish communication with an open completion interval. Because of their high viscosity and structure, foams are suitable cleanout fluids when underbalanced well-cleanout operations are applied. Although several studies have been conducted to better understand foam-flow behavior and hydraulics, investigations performed on foam stability are very limited. Specifically, very little is known regarding the impact of wellbore inclination on the stability of foams. Unstable foams do not possess high viscosity, and as a result, they are not effective in cleanout operations, especially in inclined wellbores. Predicting the downhole instability of foam could reduce the number of drilling problems associated with excessive liquid drainage, such as temporary overbalance, formation damage, and wellbore instability. The objectives of this study are to investigate the effects of wellbore inclination on the stability of various types of foams and develop a method to account for the effect of inclination on foam stability in inclined wells.In this study, foam-drainage experiments were performed using a flow loop that consists of a foam-drainage-measurement section and pipe viscometers. To verify proper foam generation, foam viscosity was measured using pipe viscometers and compared with previous measurements. Drainage experiments were performed with aqueous, polymer-based, and oil-based foams in concentric annulus and pipe under pressurized conditions. Tests were also conducted in vertical and inclined orientations to examine the effect of wellbore inclination on the stability of foams. The foam-bubble structure was examined and monitored in real time using a microscopic camera to study bubble coarsening. The foam quality (i.e., gas volume fraction) was varied from 40 to 80%.Results show that the drainage rates in the pipe and annular section were approximately the same, indicating a minor effect of column geometry. More importantly, the drainage rate of foam in an inclined configuration was significantly higher than that observed in a vertical orientation. The inclination exacerbated foam drainage and instability substantially. The mechanisms of foam drainage are different in an inclined configuration. In inclined wellbores, drainage occurs not only axially but also laterally. As a result, the drained liquid quickly reaches a wellbore wall before reaching the bottom of foam column. Then, a layer of liquid forms on the low side of the wellbore. The liquid layer flows downward because of gravity and reaches the bottom of the test section without facing the major hydraulic resistance of the foam network. This phenomenon aggravates the drainage process considerably.Although foam-drainage experiments have been reported in the literature, there exists only limited information on the effects of geometry and inclination on foam drainage and stability. The information provided in this paper will help to account for the effect of inclination on foam stability and subsequently improve the performance of oilfield operations involving foam as the working fluid.

Utilization of microcomputed tomography and pore network modeling to characterize foam dynamics

Drainage and diffusive coarsening are strongly interrelated mechanisms, which need to be studied in conjunction to acquire a thorough understanding of foam dynamics and stability. We show that microcomputed tomography (μ-CT) and pore network modeling (PNM) are valuable tools to characterize foam dynamics. Unlike existing technologies, the presented approach allows for the temporal and spatial measurement of Plateau border thickness and the volume of nodes, which are useful to study foam drainage. The coordination number of the nodes show a deviation from Plateau’s law as the foam becomes wetter. Additionally, the PNM results demonstrate a power-law relationship between permeability (κ) and liquid fraction (Φl) with an exponent of 2.6, which aligns with a channel-dominated flow regime. Overall, the proposed methodology provides a novel means to examine relevant parameters that influence foam stability and would be a valuable tool to study existing models related to foam dynamics.

Drainage of high-consistency fiber-laden aqueous foams

Lightweight lignocellulosic fibrous materials (LLFMs) offer a sustainable and biodegradable alternative in many applications. Enthusiastic interest in these materials has recently grown together with the newly risen interest in foam forming. Foam bubbles restrain fiber flocculation, and foam formed structures have high uniformity. Moreover, the bubbles support the fibrous structure during manufacturing enabling the formation of highly porous structures. Mechanical pressure cannot be applied in the manufacture of LLFMs as the materials would lose their porous structure. Water is therefore typically removed by a combination of drainage and thermal drying. Thermal drying of porous materials has been studied intensively. However, there are only a few studies on the drainage of fiber-laden foams. Thus, in this work, we conducted a systematic analysis of this topic. Our findings show that after drainage a stationary vertical moisture profile similar to that of pure foams is developed. Raising the initial fiber consistency was found to increase the final fiber consistency of the foam until the drainage ceased. Increasing mold height was found to increase the final consistency considerably. Without vacuum and heating, the shrinkage of samples during drainage was only slightly higher than the volume of the drained water. Drainage rate and final consistency increased clearly with increasing vacuum, but simultaneously sample shrinkage increased considerably. The best compromise was obtained with a vacuum of 0.5 kPa, which increased the final consistency by 60% without extra shrinkage. Using warm foam and heating the foam during drainage increased the final consistency considerably, but this also led to significant shrinkage of the sample.

A numerical approach for the nonlinear temporal conformable fractional foam drainage equation

In this paper, we examine a novel method called the residual power series method (RPSM) which is used in finding an analytic approximate solution to the nonlinear temporal foam drainage equation of fractional order. The solution is obtained in a uniformly convergent series form. Also, 3D graphs for the solution are provided for different values of [Formula: see text] which proves that the method is an effective and straightforward approach of providing excellent results for similar problems.

Role of nanoparticles in the performance of foam stabilized by a mixture of hydrocarbon and fluorocarbon surfactants

The molecular interaction, foaming ability, and foam stability of the mixtures of hydrophilic silica nanoparticles, a cationic hydrocarbon surfactant, and a nonionic short-chain fluorocarbon surfactant were studied systematically. The results indicate that nanoparticle concentration has a considerable impact on surface activity, dynamic viscosity, conductivity, foaming ability, and foam stability. The surface activity and dynamic viscosity of the foam dispersions increased rapidly with increasing nanoparticle concentration. The conductivity and foaming ability of the dispersions decreased with the addition of nanoparticles and further decreased with increasing nanoparticle concentration. At a nanoparticle concentration below 0.1%, the addition of nanoparticles accelerated foam drainage and coarsening. At a nanoparticle concentration above 0.1%, the addition of nanoparticles enhanced foam stability by decelerating foam drainage and foam coarsening. The foam stability was further enhanced as the nanoparticle concentration increased. This study provides a basis for the application of foams stabilized by nanoparticles in fire extinguishing agents.

Foaming Agent Developed for Gas Wells with Liquid Loading Problem Using New Surfactant and Nanotechnology

Summary Liquid buildup in the wellbore is one of the major causes of production decline in gas wells, in which case additional energy is needed to drain off the liquid to solve this problem. Foaming agents offer a method to reduce the liquid density to make it easier to be lifted with the gas flow, unloading the accumulated liquid in gas wells. The main ingredient of foaming agents are surfactants. Foam stability is influenced by several factors, such as salinity, temperature, and pressure, so a foaming stabilizer is usually needed for a foam system. A foaming agent should be developed to form stable foams in the presence of a salt or sweet-water hydrocarbon phase at a given temperature and pressure. Recently, various kinds of foaming agents have been developed and discussed. Previous studies mainly focused on the complex interaction between an anionic surfactant and amphoteric ion surfactant; however, stability of the foam system formed by these foaming agents needs to be further improved (Nikolai et al. 2009). Therefore, development of a novel foaming agent with improved stability is necessary, especially for the application under downhole conditions. The complex interaction between the anionic and cationic surfactants is neglected in previous research. For example, the synergies between the anionic and cationic surfactants with appropriate methods can greatly improve the foam stability compared with the one-component system. A complex phase behavior and microstructure that has a high surface activity and foam stability can be obtained by the strong electrostatic interaction between the opposite charge ionic head groups and the hydrophobic interaction between the hydrocarbon groups. A gemini surfactant with a spacer can make the molecules pack tighter and increase the surfactant cohesion within the monolayer, which can greatly enhance the foam stability. The liquid film of foam formed by the surfactant is dynamically unstable because the liquid film cannot prevent the diffusion of gas, and the foam will burst quickly. However, solid films with particles adsorbed in the gas/water interface can weaken the foam drainage speed, so that the foam stability is greatly enhanced. In summary, a robust foaming agent is developed with the introduction of an anionic-nonionic surfactant complexed with a gemini cationic surfactant; moreover, nanoparticles with a certain hydrophilicity and size are also adopted as stabilizers.

Cheese powder production and characterization: A foam-mat drying approach

Herein, white cheese powder was produced using a foam mat drying method. Foaming conditions namely amount of white cheese (40, 50 and 60% w/w), whey protein concentrate (WPC) (1, 3 and 5% w/w) and foaming temperature (30, 55 and 80 °C) were investigated on the foam density (FD), drainage volume (DV) and surface tension. Surface tension generally decreased with increasing of WPC content and temperature. The best conditions to produce ideal white cheese foam were WPC 3% (w/w), white cheese 60% (w/w) and whipping temperature 55 °C. Ideal foam dried at temperatures of 50, 65 and 80 °C on 1, 3 and 5 mm thicknesses. The effective moisture diffusivity varied from 0.906 × 10−8 to 1.771 × 10−8 m2/s, and from 3.398 × 10−8 to 7.066 × 10−8 m2/s, and from 43.626 × 10−8 to 282.185 × 10−8 m2/s with activation energy values of 21.351, 23.358 and 58.811 kJ/mol for 1, 3 and 5 mm thicknesses, respectively. The analysis of powders showed that the temperature increase and thickness reduction, significantly reduced moisture content and water activity, but no significant difference was found between the powders’ hygroscopicity. The powders produced at 65 °C resulted higher L* and a*. Protein and fat contents of powder in ideal drying conditions (3 mm–65 °C) were 46.59 and 37.25% respectively, that is a rich source of protein and fat to use in ready-to-eat and/or ready-to-cook meals.

In-situ rheological and structural characterization of milk foams in a commercial foaming device

Processing, stability and sensorial perception of food foams are tightly related to their microstructure and flow behavior. Characterization of corresponding physical parameters is central for product development and quality control. An experimental setup enabling in-situ characterization of yield stress, gas volume fraction and bubble size distribution at different heights within a foam column created in a commercial whipping device is presented. Reliable determination of these quantities is shown. Foams made from regular and reconstituted milk have been investigated. Gas volume fraction and bubble size increase monotonically during free drainage. Related to the changes in these parameters, the yield stress increases strongly during initial drainage and weaker in mature foams. Gradients of the structural and rheological parameters along the direction of gravity increase over time. Yield stresses in these milk foams are as predicted from phenomenological modelling including the above parameters, emphasizing the reliability of the measurement setup. • In-situ characterization of milk foam shows vertical gradients in foam structure and yield stress. • Average bubble size and distribution span both increase linearly with drainage time. • Average bubble size increases with height and the gradient increases with time. • Foam yield stress and gas volume fraction increase with foam age and height in foam.

Analytical methods: Nonlinear longitudinal wave equation in a magnetoelectro-elastic circular rod, foam drainage and modified Degasperis–Procesi models arising in nonlinear water wave models

We form the analytical solitary wave solutions with the execution of generalized direct algebraic technique on three well-known nonlinear wave models, namely, called foam drainage, longitudinal magnetoelectro-elastic circular rod and modified Degasperis–Procesi equations. The derived solutions are hyperbolic functions in which some are plotted graphically on meticulous values to the parameters which provides the basic knowledge to understand physical significant of these three wave models. The obtained solutions show the efficiency and precision of our scheme. These derived new results prove that our novel technique is awfully effective and can be productive as a instrument solving for sundry other nonlinear evolution equations.

A novel algorithm for time-fractional foam drainage equation

In this work, we present a novel numerical algorithm for solving the nonlinear time-fractional foam drainage equation at early stages of the time. The analytical solution of the nonlinear time-fractional foam drainage equation is represented by a linear combination of fractional Bernstein basis polynomials over a time interval [0,T]. Detailed numerical algorithm with several theoretical results are discussed. Several examples are discussed to test the efficiency and accuracy of the present scheme.

MULTIPLE EXACT SOLUTIONS OF THE GENERALIZED TIME FRACTIONAL FOAM DRAINAGE EQUATION

In this paper, we investigate the exact solutions of the generalized time fractional foam drainage equation. The Lie-group scaling transformation method and improved [Formula: see text]-expansion method are adopted here. The equation describes the evolution of the vertical density profile of a foam under gravity. New exact solutions and maple diagrams of the generalized time fractional foam drainage equation can help us better understand the physical phenomena.

Modelling of foamed emulsion drainage

The drainage of foams created using emulsions has been investigated from both experimental and theoretical point of view. The drainage of emulsion foam is investigated using mixture of sodium dodecyl sulphate and oil, which were prepared using the double syringe method. For the preparation of each emulsion, SDS solution and oil are passed from one syringe into the other through a plastic tube leading to thorough mixing. In the course of drainage both the foam height and the thickness of the free liquid layer accumulated at the bottom of the foam were measured. A theoretical model was developed, taking into account both surface viscosity and non-Newtonian behaviour of the foamed emulsion to describe the time evolution of both the foam height and the thickness of the free liquid layer. The model is based on consideration of drainage of non-Newtonian liquid through the Plateau borders and the mobility of the gas/liquid interface is taken into account. Both experiments and theoretical predictions show no measurable change of the foam height while a free liquid layer starts to accumulate at the bottom boundary of the foam after an initial rapid increase of liquid volume fraction to the maximum value at the bottom of the foam. Theoretical predictions of rate of drainage, free liquid layer formation, foam height and liquid volume fraction for foamed emulsion systems of various oil volume fractions are compared with experimental observations. Comparison of the predicted and the experimentally measured time dependences showed a reasonable agreement.

Surfactant dynamics: hidden variables controlling fluid flows.

Surfactants - molecules and particles that preferentially adsorb to fluid interfaces - play a ubiquitous role in the fluids of industry, of nature, and of life. Since most surfactants cannot be seen directly, their behavior must be inferred from their impact on observed flows, like the buoyant rise of a bubble, or the thickness of a coating film. In so doing, however, a difficulty arises: physically distinct surfactant processes can affect measurable flows in qualitatively identical ways, raising the specter of confusion or even misinterpretation. This Perspective describes, in one coherent piece, both the equilibrium properties and dynamic processes of surfactants, to better enable the fluid mechanics community to understand, interpret, and design surfactant/fluid systems. Specifically, §2 treats the equilibrium thermodynamics of surfactants at interfaces, including surface pressure, isotherms of soluble and insoluble surfactants, and surface dilatational moduli (Gibbs and Marangoni). §3 describes surfactant dynamics in fluid systems, including surfactant transport and interfacial stress boundary conditions, the competition between surface diffusion, advection, and adsorption/desorption, Marangoni stresses and flows, and surface excess rheology. §4 discusses paradigmatic problems from fluid mechanics that are impacted by surfactants, including translating drops and bubbles, surfactant adsorption to clean and oscillating interfaces; capillary wave damping, thin film dynamics, foam drainage, and the dynamics of particles and probes at surfactant-laden interfaces. Finally, §5 discusses the additional richness and complexity that frequently arise in 'real' surfactants, including phase transitions, phase coexistence, and polycrystalline phases within surfactant monolayers, and their impact on non-Newtonian surface rheology.

Endoscopic negative pressure therapy with open-pore film drainage and open-pore polyurethane sponge drainage for iatrogenic perforation of the esophagus.

Management of iatrogenic esophageal perforation (IEP) is challenging. Endoscopic negative pressure therapy (ENPT) is an emerging and effective tool for the treatment of gastrointestinal and anastomotic leaks. We have used ENPT as first-line therapy for IEP since 2017. The aim of this study was to present our results with this strategy in patients with IEP. Nine patients were treated with ENPT for IEP between August 2017 and August 2019. Their treatment characteristics, including duration of therapy, strategy used, and outcomes, were analyzed. Treatment included ENPT with open-pore film drainage (OFD) and open-pore polyurethane foam drainage (OPD). Early diagnosis (< 24 hours) of IEP occurred in four patients. After a mean (standard deviation) of 19.0 (13.5) days of ENPT, 6.4 (3.4) endoscopies, and 38.1 (40.3) days of hospitalization, endoscopic treatment was effective and successful in all of the patients. Additional video-assisted thoracic surgery (VATS) was done in four patients. ENPT is an effective new method for the management of IEP. ENPT with OFD and OPD can be combined with minimally invasive operative methods for sepsis control in IEP.

Effect of CaCl2 on the stability and rheological properties of foams and high-sugar aerated systems produced by preheated egg white protein

This study aimed to evaluate foams and meringues produced from preheated egg white protein (PH-EWP) in the presence of CaCl2 as compared to those from native egg white protein (native EWP). EWP solution was heated at alkaline condition (pH 11.3) to form a solution of denatured protein. While both the native and PH-EWP solutions showed similar foaming capacity, liquid drainage was significantly lower for the latter foams than the former ones. Furthermore, while CaCl2 had no significant effect on drainage of native EWP based foams, the addition of CaCl2 significantly decreased the drainage of the PH-EWP foams probably by forming a viscoelastic network at the bubble surface. As a proof-of-concept for the application of the PH-EWP in an actual food product, stability and rheological properties of French meringues produced by native EWP and PH-EWP were investigated. While French meringues prepared from native EWP showed an undesirable runny texture, French meringues made with PH-EWP, particularly those supplemented with CaCl2, had a stronger viscoelastic network with a higher zero-shear viscosity, yield stress, and elastic modulus so that the meringues could support its weight under gravity, rather like a dollop of whipped dairy cream. This research has developed a new method to stabilize food foam systems by using PH-EWP as a dual function ingredient, not only facilitating foam formation but also as the thickening and structuring agents to stabilized them in the presence of Ca2+.

Foam fractionation for effectively recovering copper from the discarded printed circuit board of personal computer

ABSTRACT In this work, copper (Cu) was recovered from the discarded printed circuit board (PCB) of personal computer through foam fractionation. The discarded PCB was treated by acid leaching. The leaching yield of Cu ion reached 97.61% under the conditions of temperature 40ºC, nitric acid concentration 6 mol/L and leaching time 60 min. A novel foam fractionation column was developed to strengthen foam drainage. Under the suitable conditions of pH 4.0, volumetric airflow rate 70 mL/min, SDS concentration 0.12 g/L and loading liquid volume 500 mL, enrichment ratio and recovery percentage of Cu ion were 29.1% and 90.2%, respectively.

Foaming and surface rheological behaviors of gliadin particles: Effect of solvent and concentration of gliadin stock solution

The anti-solvent method was a green and facile approach to prepare water-insoluble proteins-based colloidal particles. The structure and functional properties of the resulting particles strongly depend on the preparation parameters of the anti-solvent process. Herein, two main parameters, solvent and concentration of protein stock solution, were chosen to investigate their effects on the structural, foaming, and surface rheological properties of gliadin particles. When the solvent was 70% ethanol solution (v/v), gliadin particles exhibited a uniform spherical structure. They could fast adsorb to the air/water interface and form a viscoelastic surface layer to prevent foam drainage, coalescence, and disproportionation, thus leading to impressive foamability (~250%) and high foam stability (~60 h) even the concentration of particles was very low (1.5 mg/mL). Besides, when the solvent was acetic acid, gliadin particles possessed spherical and wire-like hybrid structures. They had slower adsorption rate and weaker interaction at the interface when compared to the ethanol-based particles, resulting in poorer foam capacity and lower foam stability. The particles prepared by different solvents had evidently different nonlinear surface rheological responses. Besides, the concentration of gliadin stock solutions did not affect the foaming and surface behaviors of particles. The particle shape played a crucial role in affecting the foaming properties and surface behaviors of gliadin particles. Results imply that 70% ethanol aqueous solution is a good solvent for gliadin, which can endow strong foaming and surface rheological behaviors to gliadin particles.

Numerical Solution of Nonlinear the Foam Drainage Equation via Hybrid Method

Numerical Solution of Nonlinear the Foam Drainage Equation via Hybrid Method

Interfacial characteristics and the stability mechanism of a dispersed particle gel (DPG) three-phase foam

Dispersed particle gel (DPG) was added to foams to obtain a more stable foam system: the DPG three-phase foam. Film drainage, interfacial rheology, and stability mechanism of the DPG three-phase foam were studied. The foam volume of the DPG three-phase foam was slightly higher than that of the traditional foam, and the half-decay time was five times that of the traditional foam. The results of film drainage show that DPG particles mainly improve the stability of thin films, i.e., the ability to bond with and capture water. Interfacial characteristics were investigated by the interfacial tension relaxation method. DPG particles slowed down the overall molecular relaxation process of the foam system, which enhanced the viscoelasticity and the mechanical strength of the interface. The stability mechanism can be explained as follows. The adsorption between DPG particles and Tetradecyl hydroxyl sulfobetaine (THSB) occurs owing to the hydrophobic attractive interaction. Therefore, DPG particles aggregate at the interface to form a shell structure, which increases the mechanical strength of the thin film by its low relaxation process; thus, a stable interface is formed, and the stability of the foam is enhanced.