Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechani...Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope(SEM),UV adsorption spectrophotometric concentration measurement and Zeta potential measurement.When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 751 s to 239 s,and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s.When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 526 s to 171 s,and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s.In addition,due to asphaltene-SDS/silica interaction in the aqueous phase,the absolute value of Zeta potential decreases,and the surface charges of particles reduce,leading to the reduction of repulsive forces between two interfaces of thin liquid film,which in turn,damages the foam stability.展开更多
Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical ...Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical microscopy,scanning electron microscopy(SEM) and Auger electron spectroscopy(AES) were used to analyze the influence of oxygen content on cell structure,relative density,macro and micro morphology of cell walls,coverage area fraction of oxide film,thickness of oxide film and other aspects.Results indicate that the coverage area fraction of oxide film on bubble surface increases with the increase of oxygen content when the oxygen volume is less than 1.2%.While when the oxygen volume fraction is larger than 1.6%,an oxide film covers the entire bubble surface and aluminum foams with good cell structure can be produced.The thicknesses of oxide films of aluminum foams produced by gas mixtures containing 1.6%-21%oxygen are almost the same.The reasons why the thickness of oxide film nearly does not change with the variation of oxygen content and the amount of oxygen needed to achieve 100%coverage of oxide film are both discussed.In addition,the role of oxide film on bubble surface in foam stability is also analyzed.展开更多
The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were t...The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.展开更多
Lauryl betaine(LB)as an amphoteric surfactant carries both positive and negative charges and should be able to generate stable foam through electrostatic interaction with nanoparticles and co-surfactants.However,no pr...Lauryl betaine(LB)as an amphoteric surfactant carries both positive and negative charges and should be able to generate stable foam through electrostatic interaction with nanoparticles and co-surfactants.However,no previous attempts have been made to investigate the influence of nanoparticles and other co-surfactants on the stability and apparent viscosity of LBstabilized foam.In this study,a thorough investigation on the influence of silicon dioxide(SiO2)nanoparticles,alpha olefin sulfonate(AOS)and sodium dodecyl sulfate(SDS),on foam stability and apparent viscosity was carried out.The experiments were conducted with the 2D Hele-Shaw cell at high foam qualities(80%-98%).Influence of AOS on the interaction between the LB foam and oil was also investigated.Results showed that the SiO2-LB foam apparent viscosity decreased with increasing surfactant concentration from 0.1 wt%to 0.3 wt%.0.1 wt%SiO2 was the optimum concentration and increased the 0.1 wt%LB foam stability by 108.65%at 96%foam quality.In the presence of co-surfactants,the most stable foam,with the highest apparent viscosity,was generated by AOS/LB solution at a ratio of 9:1.The emulsified crude oil did not imbibe into AOS-LB foam lamellae.Instead,oil was redirected into the plateau borders where the accumulated oil drops delayed the rate of film thinning,bubble coalescence and coarsening.展开更多
The two kinds of rigid polyurethane (PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in...The two kinds of rigid polyurethane (PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.展开更多
Cocamidopropyl hydroxyl sulfobetaine(CHSB)is one of the most promising foaming agents for high-salinity reservoirs because the salt in place facilitates its foam stability,even with salinity as high as 2×10^(5)mg...Cocamidopropyl hydroxyl sulfobetaine(CHSB)is one of the most promising foaming agents for high-salinity reservoirs because the salt in place facilitates its foam stability,even with salinity as high as 2×10^(5)mg/L.However,the synergistic effects between CHSB and salt have not been fully understood.This study utilized bulk foam tests and thin-film interferometry to comprehensively investigate the macroscopic and microscopic decay processes of CHSB foams with NaCl concentrations ranging from 2.3×10^(4)to 2.1×10^(5)mg/L.We focused on the dilatational viscoelasticity and dynamic thin-film thickness to elucidate the high-salinity-enhanced foam stability.The increase in dilatational viscoelasticity and supramolecular oscillating structural force(Π_(OS))with salinity dominated the superior stability of CHSB foam.With increasing salinity,more CHSB molecules accumulated on the surface with a lower diffusion rate,leading to high dilatational moduli and surface elasticity,thus decelerating coarsening and coalescence.Meanwhile,the number density of micelles in the thin film increased with salinity,resulting in increasedΠOS.Consequently,the energy barrier for stepwise thinning intensified,and the thin-film drainage slowed.This work conduces to understand the mechanisms behind the pronounced stability of betaine foam and can promote the widespread application of foam in harsh reservoirs.展开更多
Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming ...Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming agent, TiH2, was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved. The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process. When rolling reduction is 67%, the consistency of powders reach to 99.87%. Throughout consideration of the bonding of face sheet/ core layer powders and deformation characteristic of powders, the optimum rolling reduction is 60%-70%. Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg. The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃; the amount of adding Mg is 1wt%.展开更多
A low-cost eco-friendly aqueous foam,especially the robust foam with great tolerance to high salinity and high temperature,is in great demand in the oil industry,e.g.,oil and gas well or geothermal well drilling.Herei...A low-cost eco-friendly aqueous foam,especially the robust foam with great tolerance to high salinity and high temperature,is in great demand in the oil industry,e.g.,oil and gas well or geothermal well drilling.Herein,an ultra-stable aqueous foam was developed using the biodegradable cellulose microfiber(CMF)as a foam stabilizer.The foam stabilized by CMF shows excellent tolerance to the high concentration of NaCl(6.0 wt%)and CaCl_(2)(0.25 wt%)and the related drainage half-life times(T_(0.5))reach 1750 and 2340 s respectively.By contrast,the foams without CMF are completely drained(T_(0.5)=0 s)when NaCl concentration is greater than 6.0 wt%or CaCl_(2) concentration is greater than 0.20 wt%.Notably,T0.5 of the foams stabilized by CMF at these saline concentrations still can maintain above 1000 s even after aging at 120℃ for 16 h,exhibiting an outstanding foam-stabilizing performance at high temperature.Experimental results suggest that the salt and high-temperature tolerance of CMF in foam stabilization is attributed to the electrically uncharged surfaces,the formation of a gel-like structure and the excellent thermal stability.This work not only provides a promising candidate of aqueous foam stabilizer to deal with high temperature and high salinity but also presents a natural-based solution for an environmentally friendly drilling industry in the future.展开更多
This work presents the design of a robust foam formulation that tolerates harsh reservoir conditions(high salinity,high divalent ion concentration,high temperature,light oil,and hydrocarbon injection gas)in a sandston...This work presents the design of a robust foam formulation that tolerates harsh reservoir conditions(high salinity,high divalent ion concentration,high temperature,light oil,and hydrocarbon injection gas)in a sandstone reservoir.For this,we selected anionic Alpha Olefin Sulfonate(AOS)surfactants and studied their synergistic effects in mixtures with zwitterionic betaines to enhance foam performance.The laboratory workflow used to define the best formulation followed a de-risking approach in three consecutive phases.First,(phase 1)the main surfactant(AOS)was selected among a series of commercial candidates in static conditions.Then,(phase 2)the betaine booster to be combined with the previously selected AOS was chosen and their ratio optimized in static conditions.Subsequently,(phase 3)the surfactant/booster ratio was optimized under dynamic conditions in a porous medium in the absence and the presence of oil.As a result of this study,a mixture of an AOS C14-C16 and cocamidopropyl hydroxysultaine(CAPHS)was selected as the one having the best performance.The designed formulation was proven to be robust in a wide range of conditions.It generated a strong and stable foam at reservoir conditions,overcoming variations in salinity and foam quality,and tolerated the presence of oil.展开更多
As a solid foam stabilizer, spherical silica particles with diameters ranging from 150 to 190 nm were prepared via an improved Stober methOd and were subsequently modified using three different silane coupling agents ...As a solid foam stabilizer, spherical silica particles with diameters ranging from 150 to 190 nm were prepared via an improved Stober methOd and were subsequently modified using three different silane coupling agents to attain the optimum surface hydrophobicity of the particles. Fourier transform infrared (FTIR) spectra and the measured contact angles were used to characterize the surface properties of the prepared particles. The foam stability was investigated by the foam drainage half-life and the expansion viscoelastic modulus of the liquid film. The results demonstrate that all of the modified silica nanoparticles effectively improve the foam stability. The surface hydrophobicity of the modified particles is found to be a key factor influencing the foam stability. The optimum contact angle of the particles lies in the ap- proximate range from 50° to 55°. The modifier molecular structure used can also influence the stabilizing foam property of the solid particles The foam system stabilized by (CH3)2SiCl2-modified silica particles exhibits the highest stability; its drainage half-life at maximum increases by 27% compared to that of the blank foam system and is substantially greater than those of the foam systems stabilized by KH570- and KH550-modified particles.展开更多
Influence of silicon oxide(SiO_2) and aluminum oxide(Al_2O_3) nanoparticles on the stability of nanoparticles and sodium dodecyl sulfate(SDS) mixed solution foams was studied at bulk and bubble-scale. Foam apparent vi...Influence of silicon oxide(SiO_2) and aluminum oxide(Al_2O_3) nanoparticles on the stability of nanoparticles and sodium dodecyl sulfate(SDS) mixed solution foams was studied at bulk and bubble-scale. Foam apparent viscosity was also determined in Hele-Shaw cell In order to investigate the foam performance at static and dynamic conditions. Results show that the maximum adsorption of surfactant on the nanoparticles occurs at 3 wt% surfactant concentration. Foam stability increases while the foamability decreases with the increasing nanoparticle concentration. However, optimum nanoparticle concentration corresponding to maximum foam stability was obtained at 1.0 wt% nanoparticle concentration for the hydrophilic SiO_2/SDS and Al_2O_3/SDS foams. Foam performance was enhanced with increasing nanoparticles hydrophobicity. Air-foams were generally more stable than CO_2 foams.Foam apparent viscosity increased in the presence of nanoparticles from 20.34 mPa·s to 84.84 mPa·s while the film thickness increased from 27.5 μm to 136 μm. This study suggests that the static and dynamic stability of conventional foams could be improved with addition of appropriate concentration of nanoparticles into the surfactant solution. The nanoparticles improve foam stability by their adsorption and aggregation at the foam lamellae to increase film thickness and dilational viscoelasticity. This prevents liquid drainage and film thinning and improves foam stability both at the bulk and bubble scale.展开更多
Surface dilational rheological behavior and foam stability of starch/surfactant mixed solutions were studied at different starch concentrations and constant surfactant concentration. The results show that dilational v...Surface dilational rheological behavior and foam stability of starch/surfactant mixed solutions were studied at different starch concentrations and constant surfactant concentration. The results show that dilational viscoelasticity modulus, dilational elasticity modulus and dilational viscosity modulus increase with the concentration of starch particles. Foam stability increases with dilational viscoelasticity. Foam strength also increases with starch concentration. Starch particles play a positive effect on foam stability and dilational viscoelasticity and the effect becomes more significant as drainage proceeds. Film pictures indicate that the film with 20%(by mass) starch particles is thicker than that without starch. Starch particles gather in Plateau border and resist drainage, making the foam more stable.展开更多
The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and lo...The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and low ductility was introduced.And it was made as filling material of reserved deformation layer between the first lining and the second lining used in large-span soft rock tunnel.The effect of the new type of foam concrete was simulated as filling material of reserved deformation layer using numerical simulation.Through the comparison with the common large-span soft rock tunnel,the vault settlement and surrounding convergence are reduced by about 61% and 45%,respectively,after creep of 100 a.And in the second lining,the plastic zone reduces apparently and the maximum equivalent plastic strain decreases relatively.So,it can be found that the application of the new type of foam concrete as the filling material of reserved deformation layer can relieve the excessive force in second lining induced by rock creep,reduce its deformation and improve the stability of tunnel.展开更多
The leakage of organic phase change materials(OPCMs)at temperatures above their melting point severely limits their large-scale application.The introduction of porous supports has been identified as an efficient leaka...The leakage of organic phase change materials(OPCMs)at temperatures above their melting point severely limits their large-scale application.The introduction of porous supports has been identified as an efficient leakageproofing method.In this study,a novel carbonized Cu-coated melamine foam(MF)/reduced graphene oxide(rGO)framework(MF/rGO/Cu-C)is constructed as a support for fabricating stabilized multifunctional OPCMs.MF serves as the supporting material,while rGO and Cu act as functional reinforcements.As a thermal energy storage material,polyethylene glycol(PEG)is encapsulated into MF/rGO/Cu-C through a vacuum-assisted impregnation method to obtain PEG@MF/rGO/Cu-C composite with excellent comprehensive performance.PEG@MF/rGO/Cu-C exhibits high phase change enthalpies of 148.3 J g^(-1)(melting)and 143.9 J g^(-1)(crystallization),corresponding to a high energy storage capability of 92.7%.Simultaneously,MF/rGO/Cu-C endues the composite with an enhanced thermal conductivity of 0.4621Wm^(-1) K^(-1),which increases by 463%compared to that of PEG@MF.Furthermore,PEG@MF/rGO/Cu-C displays great light-to-thermal and electric-to-thermal conversion capabilities,thermal cycle stability,light-tothermal cycle stability,and shape stability,showing promising application prospects in different aspects.展开更多
Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer (NDJ-1 ), universal testing machine (Instron3365), s...Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer (NDJ-1 ), universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that the viscosity of polyether polyol increases exponentially from 62 mPa s to 6 000 mPa s with the increase of functionality from 2 to 5.6, respectively. The overall density of foam increases slightly from 31.7 kg/m^3 to 37.4 kg/m^3 with increasing functionality while core density exhibited little difference. Compressive strength of foam shows the similar behavior with density except for 2-functional sample. At the same time, dimensional stability becomes better with increasing functionality except for 5.6-functional foam that has worse stability than 4.8-functional foam. From the SEM results, the functionality is not an important factor in determining distribution of cell size of foam. According to the results of thermal analysis, the glass transition temperature (T) shifts to a higher temperature from 128.9 ℃ to 166.3 ℃ for the 2 to 5.6 functional foam, respectively.展开更多
The two kinds of rigid polyurethane(PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in we...The two kinds of rigid polyurethane(PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight.The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams.The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples.The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently.Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples.The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.展开更多
In this study, a series of flame-retardant polyisocyanurate-polyurethane (PIR-PUR) foams were prepared using various concentrations (0-25% by weight) of expandable graphite (EG) and dimethyl methyl phosphonate (DMMP) ...In this study, a series of flame-retardant polyisocyanurate-polyurethane (PIR-PUR) foams were prepared using various concentrations (0-25% by weight) of expandable graphite (EG) and dimethyl methyl phosphonate (DMMP) (0-7% by weight). The effect of these additives on the properties of the PIR-PUR foams, including physico-mechanical, morphological, flame retardancy, and thermal stability, was studied. Increasing amounts of EG in the PIR-PUR foam caused a significant drop in the compression strength. However, DMMP caused the mechanical properties of PIR-PUR foam to improve compared to foam filled with EG alone. The flame retardancy of PIR-PUR foams containing both EG and DMMP was enhanced significantly compared to EG filled foams. Thermogravimetric analysis (TGA) indicated that EG enhances the thermal stability of PIR-PUR foams but that DMMP decreased it. The morphology of the residual char provided conclusive evidence for the weak thermal stability of foams filled with DMMP.展开更多
Boosted by economic development and rising living standards,the world's carbon dioxide emissions remain high.Maintaining temperature rises below 1.5℃ by the end of the century requires rapid global carbon capture...Boosted by economic development and rising living standards,the world's carbon dioxide emissions remain high.Maintaining temperature rises below 1.5℃ by the end of the century requires rapid global carbon capture and storage implementation.The successful application of carbon capture,utilization,and storage(CCUS)technology in oilfields has become the key to getting rid of this predicament.Foam flooding,as an organic combination of gas and chemical flooding,became popular in the 1950s.Notwithstanding the irreplaceable advantages,as a thermodynamically unstable system,foam's stability has long restricted its development in enhanced oil and gas recovery.With special surface/interface effects and small-size effects,nanoparticles can be used as foam stabilizers to enhance foam stability,thereby improving foam seepage and oil displacement effects in porous media.In this paper,the decay kinetics and the stabilization mechanisms of nanoparticle-reinforced foams were systematically reviewed.The effects of nanoparticle characteristics,including particle concentration,surface wettability,particle size,and type,and reservoir environment factors,including oil,temperature,pressure,and salinity on the foam stabilization ability were analyzed in detail.The seepage and flooding mechanisms of nanoparticle-reinforced foams were summarized as:improving the plugging properties of foams,enhancing the interaction between foams and crude oil,and synergistically adjusting the wettability of reservoir rocks.Finally,the challenges in the practical application of nanoparticle-reinforced foams were highlighted,and the development direction was proposed.The development of nanoparticle-reinforced foam can open the way toward adaptive and evolutive EOR technology,taking one further step towards the high-efficiency production of the petroleum industry.展开更多
Sirnak City and the surrounding areas are on steeper slopes. There are sliding large land masses or rocks. Underground water and harsh climatic conditions contain high risk hazard areas in urban living site with highe...Sirnak City and the surrounding areas are on steeper slopes. There are sliding large land masses or rocks. Underground water and harsh climatic conditions contain high risk hazard areas in urban living site with higher population density. In order to eliminate landslides and related events, significant precautions should be taken. The mapping of landslide risk may ease to take precautions. Even the application of landfill rock may reduce water content of soil. In this research, fly ash and Mine Waste shale stone were used with low density foam concrete. Waste mixture at certain proportions decreased cement use. Shale stone as fine aggregate instead of fly ash in specific proportions improved mechanical strength and porosity. Hence landslide hazardous area could be safer for urban living.展开更多
The oxidation behaviors of Ni-16Cr-xAl (x=4.5%, 9.0%, mass fraction) superalloy foams in air at 1000℃ were investigated. The effects of AI content on the resistance to high temperature oxidation were examined. The ...The oxidation behaviors of Ni-16Cr-xAl (x=4.5%, 9.0%, mass fraction) superalloy foams in air at 1000℃ were investigated. The effects of AI content on the resistance to high temperature oxidation were examined. The oxidation mechanisms of the foams were discussed. The results show that the resistance to the oxidation of the Ni-16Cr-xA1 based alloy at 1 000 ℃ increases with the content of A1 increasing from 4.5% to 9.0%. Complex oxide products are formed on the surface of the superalloy foams after the oxidation. Cr203 and A1203 are the predominant oxides for the scales of the foams with 4.5% A1 and 9% A1, respectively. Excellent high temperature oxidation resistance and superior pore conformation stability for the Ni-16Cr-xA1 based superalloy foam with 9% A1 can be mainly attributed to the formation of relatively continuous and protective A1203 oxides on the surface of the foam.展开更多
文摘Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope(SEM),UV adsorption spectrophotometric concentration measurement and Zeta potential measurement.When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 751 s to 239 s,and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s.When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 526 s to 171 s,and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s.In addition,due to asphaltene-SDS/silica interaction in the aqueous phase,the absolute value of Zeta potential decreases,and the surface charges of particles reduce,leading to the reduction of repulsive forces between two interfaces of thin liquid film,which in turn,damages the foam stability.
基金Project(51371104)supported by the National Natural Science Foundation of China
文摘Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical microscopy,scanning electron microscopy(SEM) and Auger electron spectroscopy(AES) were used to analyze the influence of oxygen content on cell structure,relative density,macro and micro morphology of cell walls,coverage area fraction of oxide film,thickness of oxide film and other aspects.Results indicate that the coverage area fraction of oxide film on bubble surface increases with the increase of oxygen content when the oxygen volume is less than 1.2%.While when the oxygen volume fraction is larger than 1.6%,an oxide film covers the entire bubble surface and aluminum foams with good cell structure can be produced.The thicknesses of oxide films of aluminum foams produced by gas mixtures containing 1.6%-21%oxygen are almost the same.The reasons why the thickness of oxide film nearly does not change with the variation of oxygen content and the amount of oxygen needed to achieve 100%coverage of oxide film are both discussed.In addition,the role of oxide film on bubble surface in foam stability is also analyzed.
文摘The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.
文摘Lauryl betaine(LB)as an amphoteric surfactant carries both positive and negative charges and should be able to generate stable foam through electrostatic interaction with nanoparticles and co-surfactants.However,no previous attempts have been made to investigate the influence of nanoparticles and other co-surfactants on the stability and apparent viscosity of LBstabilized foam.In this study,a thorough investigation on the influence of silicon dioxide(SiO2)nanoparticles,alpha olefin sulfonate(AOS)and sodium dodecyl sulfate(SDS),on foam stability and apparent viscosity was carried out.The experiments were conducted with the 2D Hele-Shaw cell at high foam qualities(80%-98%).Influence of AOS on the interaction between the LB foam and oil was also investigated.Results showed that the SiO2-LB foam apparent viscosity decreased with increasing surfactant concentration from 0.1 wt%to 0.3 wt%.0.1 wt%SiO2 was the optimum concentration and increased the 0.1 wt%LB foam stability by 108.65%at 96%foam quality.In the presence of co-surfactants,the most stable foam,with the highest apparent viscosity,was generated by AOS/LB solution at a ratio of 9:1.The emulsified crude oil did not imbibe into AOS-LB foam lamellae.Instead,oil was redirected into the plateau borders where the accumulated oil drops delayed the rate of film thinning,bubble coalescence and coarsening.
文摘The two kinds of rigid polyurethane (PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.
基金The authors would like to be grateful for the financial support of National Natural Science Foundation of China(No.51904256).
文摘Cocamidopropyl hydroxyl sulfobetaine(CHSB)is one of the most promising foaming agents for high-salinity reservoirs because the salt in place facilitates its foam stability,even with salinity as high as 2×10^(5)mg/L.However,the synergistic effects between CHSB and salt have not been fully understood.This study utilized bulk foam tests and thin-film interferometry to comprehensively investigate the macroscopic and microscopic decay processes of CHSB foams with NaCl concentrations ranging from 2.3×10^(4)to 2.1×10^(5)mg/L.We focused on the dilatational viscoelasticity and dynamic thin-film thickness to elucidate the high-salinity-enhanced foam stability.The increase in dilatational viscoelasticity and supramolecular oscillating structural force(Π_(OS))with salinity dominated the superior stability of CHSB foam.With increasing salinity,more CHSB molecules accumulated on the surface with a lower diffusion rate,leading to high dilatational moduli and surface elasticity,thus decelerating coarsening and coalescence.Meanwhile,the number density of micelles in the thin film increased with salinity,resulting in increasedΠOS.Consequently,the energy barrier for stepwise thinning intensified,and the thin-film drainage slowed.This work conduces to understand the mechanisms behind the pronounced stability of betaine foam and can promote the widespread application of foam in harsh reservoirs.
基金Funded by the National Natural Science Foundation of China(No.50704012)the Science and Technology Foundation of Shenyang (No. F10-205-1-59)
文摘Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming agent, TiH2, was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved. The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process. When rolling reduction is 67%, the consistency of powders reach to 99.87%. Throughout consideration of the bonding of face sheet/ core layer powders and deformation characteristic of powders, the optimum rolling reduction is 60%-70%. Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg. The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃; the amount of adding Mg is 1wt%.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51991361 and Grant No.51991362)the foundation of China University of Petroleum(Beijing)(Grant No.2462021YXZZ002).
文摘A low-cost eco-friendly aqueous foam,especially the robust foam with great tolerance to high salinity and high temperature,is in great demand in the oil industry,e.g.,oil and gas well or geothermal well drilling.Herein,an ultra-stable aqueous foam was developed using the biodegradable cellulose microfiber(CMF)as a foam stabilizer.The foam stabilized by CMF shows excellent tolerance to the high concentration of NaCl(6.0 wt%)and CaCl_(2)(0.25 wt%)and the related drainage half-life times(T_(0.5))reach 1750 and 2340 s respectively.By contrast,the foams without CMF are completely drained(T_(0.5)=0 s)when NaCl concentration is greater than 6.0 wt%or CaCl_(2) concentration is greater than 0.20 wt%.Notably,T0.5 of the foams stabilized by CMF at these saline concentrations still can maintain above 1000 s even after aging at 120℃ for 16 h,exhibiting an outstanding foam-stabilizing performance at high temperature.Experimental results suggest that the salt and high-temperature tolerance of CMF in foam stabilization is attributed to the electrically uncharged surfaces,the formation of a gel-like structure and the excellent thermal stability.This work not only provides a promising candidate of aqueous foam stabilizer to deal with high temperature and high salinity but also presents a natural-based solution for an environmentally friendly drilling industry in the future.
基金funded by the Centro para el Desarrollo Tecnologico Industrial(CDTI)of the Spanish Ministry of Science and Innovation(IDI-20170503)the Fundacion Cepsa with the Escuela Tecnica Superior de Ingenieros de Minas y Energia of the Universidad Politecnica de Madrid(UPM)。
文摘This work presents the design of a robust foam formulation that tolerates harsh reservoir conditions(high salinity,high divalent ion concentration,high temperature,light oil,and hydrocarbon injection gas)in a sandstone reservoir.For this,we selected anionic Alpha Olefin Sulfonate(AOS)surfactants and studied their synergistic effects in mixtures with zwitterionic betaines to enhance foam performance.The laboratory workflow used to define the best formulation followed a de-risking approach in three consecutive phases.First,(phase 1)the main surfactant(AOS)was selected among a series of commercial candidates in static conditions.Then,(phase 2)the betaine booster to be combined with the previously selected AOS was chosen and their ratio optimized in static conditions.Subsequently,(phase 3)the surfactant/booster ratio was optimized under dynamic conditions in a porous medium in the absence and the presence of oil.As a result of this study,a mixture of an AOS C14-C16 and cocamidopropyl hydroxysultaine(CAPHS)was selected as the one having the best performance.The designed formulation was proven to be robust in a wide range of conditions.It generated a strong and stable foam at reservoir conditions,overcoming variations in salinity and foam quality,and tolerated the presence of oil.
基金financially supported by the National Natural Science Foundation of China(No.21276022)the China National Petroleum Corporation Innovation Foundation(No.2012D-5006-0208)
文摘As a solid foam stabilizer, spherical silica particles with diameters ranging from 150 to 190 nm were prepared via an improved Stober methOd and were subsequently modified using three different silane coupling agents to attain the optimum surface hydrophobicity of the particles. Fourier transform infrared (FTIR) spectra and the measured contact angles were used to characterize the surface properties of the prepared particles. The foam stability was investigated by the foam drainage half-life and the expansion viscoelastic modulus of the liquid film. The results demonstrate that all of the modified silica nanoparticles effectively improve the foam stability. The surface hydrophobicity of the modified particles is found to be a key factor influencing the foam stability. The optimum contact angle of the particles lies in the ap- proximate range from 50° to 55°. The modifier molecular structure used can also influence the stabilizing foam property of the solid particles The foam system stabilized by (CH3)2SiCl2-modified silica particles exhibits the highest stability; its drainage half-life at maximum increases by 27% compared to that of the blank foam system and is substantially greater than those of the foam systems stabilized by KH570- and KH550-modified particles.
基金the Ministry of Higher Education(Vot no.Q.J130000.2542.08H61)Universiti Teknologi(UTM)Malaysia,for supporting this research through research management grant
文摘Influence of silicon oxide(SiO_2) and aluminum oxide(Al_2O_3) nanoparticles on the stability of nanoparticles and sodium dodecyl sulfate(SDS) mixed solution foams was studied at bulk and bubble-scale. Foam apparent viscosity was also determined in Hele-Shaw cell In order to investigate the foam performance at static and dynamic conditions. Results show that the maximum adsorption of surfactant on the nanoparticles occurs at 3 wt% surfactant concentration. Foam stability increases while the foamability decreases with the increasing nanoparticle concentration. However, optimum nanoparticle concentration corresponding to maximum foam stability was obtained at 1.0 wt% nanoparticle concentration for the hydrophilic SiO_2/SDS and Al_2O_3/SDS foams. Foam performance was enhanced with increasing nanoparticles hydrophobicity. Air-foams were generally more stable than CO_2 foams.Foam apparent viscosity increased in the presence of nanoparticles from 20.34 mPa·s to 84.84 mPa·s while the film thickness increased from 27.5 μm to 136 μm. This study suggests that the static and dynamic stability of conventional foams could be improved with addition of appropriate concentration of nanoparticles into the surfactant solution. The nanoparticles improve foam stability by their adsorption and aggregation at the foam lamellae to increase film thickness and dilational viscoelasticity. This prevents liquid drainage and film thinning and improves foam stability both at the bulk and bubble scale.
基金Supported by the Petro China Company Limited Project(2011B-1303)the National Natural Science Foundation of China(21276022)CNPC Innovation Foundation(2012D-5006-0208)
文摘Surface dilational rheological behavior and foam stability of starch/surfactant mixed solutions were studied at different starch concentrations and constant surfactant concentration. The results show that dilational viscoelasticity modulus, dilational elasticity modulus and dilational viscosity modulus increase with the concentration of starch particles. Foam stability increases with dilational viscoelasticity. Foam strength also increases with starch concentration. Starch particles play a positive effect on foam stability and dilational viscoelasticity and the effect becomes more significant as drainage proceeds. Film pictures indicate that the film with 20%(by mass) starch particles is thicker than that without starch. Starch particles gather in Plateau border and resist drainage, making the foam more stable.
基金Projects(41072238,51009133)supported by the National Natural Science Foundation of China
文摘The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and low ductility was introduced.And it was made as filling material of reserved deformation layer between the first lining and the second lining used in large-span soft rock tunnel.The effect of the new type of foam concrete was simulated as filling material of reserved deformation layer using numerical simulation.Through the comparison with the common large-span soft rock tunnel,the vault settlement and surrounding convergence are reduced by about 61% and 45%,respectively,after creep of 100 a.And in the second lining,the plastic zone reduces apparently and the maximum equivalent plastic strain decreases relatively.So,it can be found that the application of the new type of foam concrete as the filling material of reserved deformation layer can relieve the excessive force in second lining induced by rock creep,reduce its deformation and improve the stability of tunnel.
基金National Natural Science Foundation of China,Grant/Award Numbers:51861005,52071092,U20A20237Guangxi Natural Science Foundation,Grant/Award Numbers:2019GXNSFDA245023,2019GXNSFGA245005,2020GXNSFGA297004,2021GXNSFFA196002Guangxi Bagui Scholar Foundation。
文摘The leakage of organic phase change materials(OPCMs)at temperatures above their melting point severely limits their large-scale application.The introduction of porous supports has been identified as an efficient leakageproofing method.In this study,a novel carbonized Cu-coated melamine foam(MF)/reduced graphene oxide(rGO)framework(MF/rGO/Cu-C)is constructed as a support for fabricating stabilized multifunctional OPCMs.MF serves as the supporting material,while rGO and Cu act as functional reinforcements.As a thermal energy storage material,polyethylene glycol(PEG)is encapsulated into MF/rGO/Cu-C through a vacuum-assisted impregnation method to obtain PEG@MF/rGO/Cu-C composite with excellent comprehensive performance.PEG@MF/rGO/Cu-C exhibits high phase change enthalpies of 148.3 J g^(-1)(melting)and 143.9 J g^(-1)(crystallization),corresponding to a high energy storage capability of 92.7%.Simultaneously,MF/rGO/Cu-C endues the composite with an enhanced thermal conductivity of 0.4621Wm^(-1) K^(-1),which increases by 463%compared to that of PEG@MF.Furthermore,PEG@MF/rGO/Cu-C displays great light-to-thermal and electric-to-thermal conversion capabilities,thermal cycle stability,light-tothermal cycle stability,and shape stability,showing promising application prospects in different aspects.
基金the Joint Research Foundation of CAS and Hebei Province,China(No.2004-015)
文摘Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer (NDJ-1 ), universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that the viscosity of polyether polyol increases exponentially from 62 mPa s to 6 000 mPa s with the increase of functionality from 2 to 5.6, respectively. The overall density of foam increases slightly from 31.7 kg/m^3 to 37.4 kg/m^3 with increasing functionality while core density exhibited little difference. Compressive strength of foam shows the similar behavior with density except for 2-functional sample. At the same time, dimensional stability becomes better with increasing functionality except for 5.6-functional foam that has worse stability than 4.8-functional foam. From the SEM results, the functionality is not an important factor in determining distribution of cell size of foam. According to the results of thermal analysis, the glass transition temperature (T) shifts to a higher temperature from 128.9 ℃ to 166.3 ℃ for the 2 to 5.6 functional foam, respectively.
基金The key project of "11th Five-Year Plan" in Heilongjiang Province (No. GB06B501-3)
文摘The two kinds of rigid polyurethane(PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight.The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams.The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples.The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently.Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples.The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.
基金supported by the State Key Program of Coal Joint Funds of National Natural Science Foundation of China (No.51134020)the Natural Science Foundation of Shandong Province(No. ZR2011EL036)the High School Science & Technology Fund Planning Project of Shandong Province (No. JIILD53)
文摘In this study, a series of flame-retardant polyisocyanurate-polyurethane (PIR-PUR) foams were prepared using various concentrations (0-25% by weight) of expandable graphite (EG) and dimethyl methyl phosphonate (DMMP) (0-7% by weight). The effect of these additives on the properties of the PIR-PUR foams, including physico-mechanical, morphological, flame retardancy, and thermal stability, was studied. Increasing amounts of EG in the PIR-PUR foam caused a significant drop in the compression strength. However, DMMP caused the mechanical properties of PIR-PUR foam to improve compared to foam filled with EG alone. The flame retardancy of PIR-PUR foams containing both EG and DMMP was enhanced significantly compared to EG filled foams. Thermogravimetric analysis (TGA) indicated that EG enhances the thermal stability of PIR-PUR foams but that DMMP decreased it. The morphology of the residual char provided conclusive evidence for the weak thermal stability of foams filled with DMMP.
基金The authors thank the National Natural Science Foundation of China(Grant 52004305)the Science Foundation of China University of Petroleum,Beijing(No.2462022BJRC005)for the support of this work.
文摘Boosted by economic development and rising living standards,the world's carbon dioxide emissions remain high.Maintaining temperature rises below 1.5℃ by the end of the century requires rapid global carbon capture and storage implementation.The successful application of carbon capture,utilization,and storage(CCUS)technology in oilfields has become the key to getting rid of this predicament.Foam flooding,as an organic combination of gas and chemical flooding,became popular in the 1950s.Notwithstanding the irreplaceable advantages,as a thermodynamically unstable system,foam's stability has long restricted its development in enhanced oil and gas recovery.With special surface/interface effects and small-size effects,nanoparticles can be used as foam stabilizers to enhance foam stability,thereby improving foam seepage and oil displacement effects in porous media.In this paper,the decay kinetics and the stabilization mechanisms of nanoparticle-reinforced foams were systematically reviewed.The effects of nanoparticle characteristics,including particle concentration,surface wettability,particle size,and type,and reservoir environment factors,including oil,temperature,pressure,and salinity on the foam stabilization ability were analyzed in detail.The seepage and flooding mechanisms of nanoparticle-reinforced foams were summarized as:improving the plugging properties of foams,enhancing the interaction between foams and crude oil,and synergistically adjusting the wettability of reservoir rocks.Finally,the challenges in the practical application of nanoparticle-reinforced foams were highlighted,and the development direction was proposed.The development of nanoparticle-reinforced foam can open the way toward adaptive and evolutive EOR technology,taking one further step towards the high-efficiency production of the petroleum industry.
文摘Sirnak City and the surrounding areas are on steeper slopes. There are sliding large land masses or rocks. Underground water and harsh climatic conditions contain high risk hazard areas in urban living site with higher population density. In order to eliminate landslides and related events, significant precautions should be taken. The mapping of landslide risk may ease to take precautions. Even the application of landfill rock may reduce water content of soil. In this research, fly ash and Mine Waste shale stone were used with low density foam concrete. Waste mixture at certain proportions decreased cement use. Shale stone as fine aggregate instead of fly ash in specific proportions improved mechanical strength and porosity. Hence landslide hazardous area could be safer for urban living.
基金Project (51134003) supported by the National Natural Science Foundation of China
文摘The oxidation behaviors of Ni-16Cr-xAl (x=4.5%, 9.0%, mass fraction) superalloy foams in air at 1000℃ were investigated. The effects of AI content on the resistance to high temperature oxidation were examined. The oxidation mechanisms of the foams were discussed. The results show that the resistance to the oxidation of the Ni-16Cr-xA1 based alloy at 1 000 ℃ increases with the content of A1 increasing from 4.5% to 9.0%. Complex oxide products are formed on the surface of the superalloy foams after the oxidation. Cr203 and A1203 are the predominant oxides for the scales of the foams with 4.5% A1 and 9% A1, respectively. Excellent high temperature oxidation resistance and superior pore conformation stability for the Ni-16Cr-xA1 based superalloy foam with 9% A1 can be mainly attributed to the formation of relatively continuous and protective A1203 oxides on the surface of the foam.