The influence of solvent and demulsifier additions on nascent froth formation during flotation recovery of Bitumen from Athabasca oil sands

In the commercial slurry conditioning and flotation process applied to Athabasca oil sands the primary bituminous froth can contain significant amounts of emulsified water and suspended solids. Previous work [Fuel Process. Technol. 56 (1998) 243] has shown that a small chemical addition during the nascent froth process can yield froth of higher quality, without sacrificing bitumen recovery or increasing tight emulsion-forming tendency. In the present work we have investigated the addition of demulsifiers, mostly water-in-oil (W/O) emulsion breaking agents, in an attempt to encourage water droplet coalescence and separation from nascent froth. It was found that certain combinations of high HLB surfactants and solvents can be added in small amounts during the nascent froth process to cause significant reductions in froth water content without sacrificing bitumen recovery. The existence of an optimum surfactant concentration for such beneficial additives correlates with a minimum in interfacial tension and is consistent with conventional oilfield demulsifier experience. The application of our results could lead to a substantial increase in the throughput capacity of froth handling and treatment plants.     

Development and evaluation of oil in water nanoemulsions based on polyether silicone as demulsifier and antifoam agents for petroleum

Oil in water (o/w) nanoemulsions were synthesized in order to be evaluated as an alternative to petroleum emulsions destabilization processes and inhibition of foam formed in the crude oil. The nanoemulsions were prepared by the high energy method through High Pressure Homogenizer (HPH), utilizing poly(propylene glycol) (PPG) and xylene solvent as oil phase and different polarity polyether silicone surfactants samples. These nanoemulsions were evaluated in respect to their efficiency in the petroleum demulsification process. The results of these tests showed that nanoemulsions performance on the destabilization of petroleum emulsions is influenced by the utilized surfactant's polarity. The nanoemulsions and pure samples of PPG and xylene solvent were evaluated concerning capacity of formed foam inhibition in petroleum (antifoam test), and the results showed no significant influence of samples on foam stability. Petroleum/saline water added interfacial tension measurements, added or not the nanoemulsions were executed and showed that the additives adsorption in the interface is related to the surfactant's polarity and nanoemulsion drop size. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40889.     

Effect of oil viscosity on recovery processes in relation to foam flooding

Laboratory experiments were conducted to determine the effect of oil viscosity on the oil-recovery efficiency in porous media. The pure surfactants (i.e., sodium dodecyl sulfate and various alkyl alcohols) were selected to correlate the molecular and surface properties of foaming solutions with viscosity, and the recovery of oil. Oil-displacement efficiency was measured by water, surfactant-solution and foam-flooding processes, which included 2 types of foams (i.e., air foam and steam foam). A significant increase in heavy-oil recovery was observed by steam foam flooding compared with that by air foam flooding, whereas for light oils, the steam foam and air foam produced about the same oil recovery. An attempt was made to correlate the chain-length compatibility with the surface properties of the foaming agents and oil-recovery efficiency in porous media. For mixed foaming systems (C₁₂ SO₄ Na + C_n H_2n+1 OH), a minimum in surface tension, a maximum in surface viscosity, a minimum in bubble size and a maximum in oil recovery were observed when both components of the foaming system had the same chain length. These results were explained on the basis of thermal motions (i.e., vibrational, rotational and oscillational) and the molecular packing of surfactants at the gas-liquid interface. The effects of chain-length compatibility and the surface properties of mixed surfactants are relevant to the design of surfactant formulations for oil recovery under given reservoir conditions.     

CO2-原油体系发泡特性实验研究

为研究CO₂驱油田分离器内泡沫层产生及消除机理,设计了一套高压溶气原油泡沫测试系统,采用降压法研究了CO₂-原油体系的发泡特性。利用高速摄像机对泡沫产生至衰变的演变过程进行了记录,总结分析了不同降压阶段的气泡行为,研究了降压速率和搅拌速率对原油发泡特性的影响规律。研究发现,随压力降低,稳定存在气泡的直径增大,气泡位置上移,发泡行为更加剧烈;降压速率增加对降压阶段的发泡行为无明显影响,但会加剧稳定工作压力下的发泡行为;在转速小于等于120 r/min的条件下,搅拌速率增加会加剧降压阶段的发泡行为,但会加速稳定工作压力下的泡沫衰变。     

Removal of Emulsified Oil from Water by Coagulation and Foam Separation

Abstract

A new method of emulsified oil separation for oily wastewater incorporating simple operation and shortened treatment time is necessary for improved wastewater treatment in some manufacturing plants. In the present study, the removal of emulsified oil from water by coagulation and foam separation using poly aluminum chloride (PAC) and milk casein was examined. By adding casein before the foam separation process, the oil removal was dramatically improved. By using surfactant (LAS) as a frother, the dosage of casein was drastically reduced. Furthermore, for processing actual oily water, LAS was unnecessary because a sufficient amount of surfactants for foaming was included in the wastewater. For treatment of the actual oily wastewater collected from a steel manufacturing plant, the optimum condition for PAC and casein was 30 mg‐Al/L and 10 mg/L, respectively, and the oil concentration decreased from 170 mg/L to 2.2 mg/L. After examining several types of oily wastewater, 96–99% of oil removal efficiency was obtained by adjusting the dosages of PAC and casein. Coagulation and foam separation using casein has shown a high potential as an alternative method to dissolved air flotation (DAF) for processing emulsified oil water.     

铵盐体系香波泡沫性能的研究

研究了两种铵盐型阴离子表面活性剂与烷基单乙醇酰胺、烷基二乙醇酰胺等复配体系在不同水硬度条件下的泡沫性能 ;考察了乳化硅油、羊毛脂、十八醇、珠光剂、香精、阳离子表面活性剂及聚合阳离子化合物等添加剂在香波体系中不同水硬度条件下对发泡性能的影响。实验条件下所有体系的稳泡性均较好 ,LSA与AESA复配后泡沫力增大 ,其中AE SA含量需 <1 0 % ;含烷基单乙醇酰胺香波体系的泡沫性能优于含烷基二乙醇酰胺的 ;羊毛脂和乳化硅油对香波泡沫的影响较大 ,而其它添加剂对香波泡沫的影响不大。     

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Aqueous solutions of nonionic surfactants exhibit low foaming above their cloud point, a temperature above which the homogeneous solutions separates into two phases: a dilute phase containing a low surfactant concentration and coacervate phase containing a very high surfactant concentration (e.g., 20 wt% surfactant). In this work, foam formation was measured for the dilute phase, the coacervate, and the mixed solution using the Ross-Miles method for nonylphenol polyethoxylates with 8, 9, or 10 ethylene oxide moieties per molecule. The dilute phase showed no antifoam effect above the cloud point if the coacervate phase was not present, and the coacervate phase foamed little in the absence of the dilute phase. The coacervate phase acts as an oil droplet antifoam to the dilute phase. From surface and interfacial tension data, entering, spreading, and bridging coefficients for this system make it appear probable that the coacervate phase is forming bridges across the film lamellae of the dilute-phase foam and acting to suppress foam formation through the bridging mechanism.     

The development of heat-resistant and salt-tolerant foam with betaine surfactants

A modified instrument was designed to evaluate foam properties under high temperature and pressure. The type and molar ratio of betaine surfactants were screened to develop the heat-resistant and salt-tolerant foam for Tahe oilfield (130°C, 220 g/L), and the effects of temperature and pressure on foam properties were also investigated. The synergism between surfactants and the enhanced oil recovery (EOR) mechanism of foam flooding in fractured-vuggy reservoirs were studied. Experimental results showed the developed foam had excellent foaming ability and foam stability when the lauramidopropyl hydroxyl sulfobetaine (LHSB): erucic amide propyl betaine (EAB) molar ratio ranged from 1:1 to 1:2 (initial foam volume was 392 ml when the molar ratio was 1:1, drainage half-time was 5.75 min and foam half-time was 72 min when the molar ratio was 1:2 at 130°C and 2 MPa). The synergistic effect was found to reach its maximum when the LHSB:EAB molar ratio ranged from 1:1 to 1:2 according to interaction parameters, which agreed with the results of foam properties. Foam stability was found to considerably increase with increasing pressure, but decrease with increasing temperature. However, temperature and pressure were found to have consistent effects on foaming ability, that is, the foaming ability increased with increasing temperature and pressure. The flooding test showed foam flooding exhibited better sweep efficiency and higher recovery ratio in the fractured-vuggy model than gas flooding and water flooding. This could be because injected foam did not channel through the top (or bottom) path due to its high viscosity and moderate density.     

脂肪醇聚氧乙烯醚系列磺酸盐的泡沫性能研究

磺酸盐类阴离子表面活性剂在采油工业中应用广泛,其泡沫性能(起泡性和泡沫稳定性)对采收率影响很大。采用改进的Ross-Miles法对烷基碳数为14、16、18的脂肪醇聚氧乙烯(3)醚磺酸钠(CnH2n 1O(EO)2CH2CH2SO3Na,n=14、16、18)在不同条件下的泡沫性能进行了研究。结果表明,随着疏水基长度增加,表面活性剂起泡性降低,稳泡性增强;十四醇聚氧乙烯(3)醚磺酸钠起泡性最好,十八醇聚氧乙烯(3)醚磺酸钠稳泡性最优;随着温度的上升,3种表面活性剂起泡性增强,稳泡性降低。     

聚丙烯共混改性对其聚结除油性能的影响

采用不同性质的添加剂(CPB、CTAB、PVDF、硅蜡和长链烷基硅油)对聚丙烯进行共混改性,研究了不同改性剂对聚丙烯材料表面亲油亲水性的影响,以及改性材料在油水分离过程中的聚结除油性能。结果表明,除PVDF外,同样添加量下的不同改性剂,或同一添加剂的不同添加量,改性聚丙烯的亲水角和亲油角之差越小,越有利于聚丙烯聚结除油性能的提高;由于PVDF的疏水疏油性,有利于改性材料表面油膜的流动、脱落,以及水中油滴的聚结,其对除油效率的提高要明显高于其它的改性剂。     

Compatibilizer system for extruded polyethylene foam and film

This paper discusses the processing/product benefits of adding additives to extruded polyethylene (PE) foam and film. Low-density polyethylene foam (over 30 times expansion) requires adequate cooling to stabilize the melt/gas system for optimal foaming efficiency. The presence of a small portion of high melting polyethylenes (i.e. LLDPE, HDPE) causes flow instability after cooling, resulting in surface defects in finished products. We found that the addition of metal oxide and fatty acid ester improved processing latitude and foam product quality. This formula was also tested in film processes at various ratios of LD/LLD/HD with promising results. It appears that this formula can allow us to accommodate post consumer resin (PCR) and to take advantage of PE price variations.     

A Nanoparticle Adsorption-Based Salt-Resistant Foam for Gas Well Deliquification

With the continuous development of gas fields, water production problems are seriously affecting production rates. Aiming at the problem of the high production rates of mineralized formation water in China's gas fields, we investigate the feasibility of a foam for gas well deliquification process using a combination of nanoparticles and surfactants. Through the combination of anionic and non-ionic surfactants, a system with better foam stability is optimized by the hand-shock method. Based on the formation of hydrogen bonds between the fatty alcohol polyoxyethylene ether and SiO₂ nanoparticles, the fatty alcohol polyoxyethylene ether created hydrophobicity after silica was added. Adsorbed on the gas–liquid interface, the dilatational modulus of the gas–liquid interface increased, the shift time extended, and the diameter of the generated foam is smaller, that is, a unit volume of gas can carry more liquid. Foam stability can be adjusted by altering the pH value of the foam for gas well deliquification. Last, the oil resistance of the system was improved by adding fatty alcohols. Here, a foam for gas well deliquification was established by the combination of surfactant, nanoparticles, and fatty alcohols, which has good foaming performance, stability, and oil resistance.     

硫酸盐型孪连表面活性剂及其复配体系的泡沫性能

采用动态泡沫扫描法研究了双直链烷基硫酸盐型孪连表面活性剂水溶液的泡沫性能,并考察了添加氯化钠和疏水缔合水溶性聚丙烯酰胺(HMPAM)后对其泡沫性能的影响。结果表明,此系列孪连表面活性剂具有良好的泡沫性能;随着联接基长度的增加,表面活性剂的起泡能力略有降低,泡沫的稳定性能却明显下降;随着温度升高,泡沫半衰期显著降低;无机盐的加入使表面活性剂的起泡能力减弱,而泡沫稳定性随无机盐浓度的增加先升高后降低;HMPAM的加入明显增强了泡沫稳定性。     

Paraffin Oil Emulsions for the Absorption of Toluene Gas

Water‐in‐oil‐in‐water (W/O/W) and water‐in‐oil (W/O) emulsions of paraffin oil were prepared with sorbitan monooleate (Span 80)/polyoxyethylene sorbitan monooleate (Tween 80) or polyethylene glycol monostearate (SG‐6), respectively. The physical characteristics and the absorption of toluene gas in these emulsions were investigated to evaluate the influence of the emulsifier dosage and the oil/water ratio. Both investigated W/O/W emulsions provided high stabilities and low viscosities. The absorption of toluene gas was excellent, with little foam occurring during the absorption. Although the W/O emulsions with 2–5 % SG‐6 were of high stability, their high viscosities strongly limited their application as volatile organic compound absorbents. Stable emulsions consisted of small and uniform droplets and some emulsions underwent mild demulsification after the absorption.     

原油对水相泡沫稳定作用机理研究进展

为了评述原油对水相泡沫稳定性的影响机理,分别介绍了原油在水相泡沫中的存在状态,原油对泡沫的稳定或破坏机理。原油对泡沫的稳定性有着显著影响,稳泡或消泡也极大程度上决定了石油与天然气开采作业中,诸如泡沫驱油、泡沫堵水、堵气、泡沫排液、泡沫压裂等作业效率。重点阐述了假乳液膜对泡沫稳定性的影响机理,总结出原油在水相泡沫体系中以溶解油或乳化油两种状态存在。原油溶解于水相胶束中(溶解油)可降低泡沫的稳定性。大多原油在水相泡沫中以乳化油滴形式存在,油滴与气泡之间被假乳液膜隔开,假乳液膜决定了泡沫体系的稳定性。假乳液膜稳定性好能促进三相泡沫的稳定性;而假乳液膜稳定性差就加剧了三相泡沫地破裂。通过评述指出了原油与水相泡沫相互作用研究领域今后的研究方向。     

一种高效浓缩洗衣液的研制

初步研究了脂肪醇聚氧乙烯醚硫酸钠(AES)、醇醚羧酸盐(AEC_9)、改性油脂、烷基糖苷(APG)及异构醇聚氧乙烯醚等5种表面活性剂在浓缩洗衣液中的应用,通过对去污力、泡沫性能、水溶分散性和酶活稳定性等的测试,将此几种表面活性剂与其他助剂复配,得到一种低泡、高效浓缩洗衣液。测试结果表明,自制浓缩洗衣液稳定,去污力强、可达到4倍浓缩的效果,水溶分散性好,无凝胶出现,酶活稳定性达87.1%。     

Synergism in binary mixtures of surfactants. 7. Synergism in foaming and its relation to other types of synergism

The relationship between synergism in Ross-Miles foaming and the existence of other types of synergism in binary mixtures of surfactants has been investigated. All studies were conducted in solutions of constant ionic strength (0.1 M NaCl) at 25 and/or 60 C. Six anionic-zwitterionic or anionic-nonionic mixtures and a sodium dodecylbenzenesulfonate (LAS)-soap mixture, all consisting of commercial surfactants, were studied. Synergism in foaming effectiveness, measured by initial foam heights, appears to be related to synergism in surface tension (γ) reduction effectiveness, but not to synergism in γ reduction efficiency or in mixed micelle formation. The LAS-soap system showed negative synergism in foaming effectiveness, correlated with negative synergism in γ reduction effectiveness, the conditions for which are defined. There appears to be no correlation between synergism in foaming efficiency and synergism in either γ reduction efficiency or mixed micelle formation. There also appears to be no unambiguous relationship between foam stability, measured by the ratio of the 5-minute to the initial foam height, and the average area per surfactant molecule at the aqueous solution/air interface. Presented in part at the American Oil Chemists’ Society meeting in New Orleans in May 1987.     

壬基酚聚氧乙烯醚丙基磺酸钠的表面活性及应用性能

研究了硬水和油田水中壬基酚聚氧乙烯醚丙基磺酸钠(NPSO-5)水溶液的表面活性及应用性能,并与常用表面活性剂LAS、AOS和AES进行比较;考察了添加脂肪醇对NPSO-5体系泡沫性能的影响和NPSO-5在NaOH水溶液中的润湿性能及硬水溶液中的润湿乳化性能。结果表明,水硬度从0 mmol/L增加到80 mmol/L,NPSO-5的临界胶束浓度(CMC)从2.06×10-4 mol/L降低到7.8×10-5 mol/L;NPSO-5相对于LAS和AOS具有较强的抗硬水能力,且在硬水中具有较高的起泡能力和稳泡性能,添加脂肪醇在一定程度上改变了液膜吸附层的结构,进一步提高了体系的泡沫性能;在NaOH质量分数达12%时,NPSO-5仍然具有良好的润湿性能。     

Synthesis and Properties of Two Amino Carboxylic Acid Gemini Surfactants

The number of hydrophilic and hydrophobic groups of a surfactant has a great influence on its property. Two Gemini surfactants, N,N″‘-didodecyl-N,N',N″,N″‘-tetrapropionate triethylenetetramine and N,N'-didodecyl-N,N'-dipropionate ethylenediamine (referred as DTPTT and DDPED), were prepared by Michael addition reaction of the didodecyl secondary amines with methyl acrylate. The didodecyl secondary amines were synthesized by nucleophilic substitution reaction of triethylenetetramine or ethylenediamine with bromododecane. The DTPTT and DDPED surfactants were characterized by mass spectrometry and proton nuclear magnetic resonance spectrometry. The surface activities of the DTPTT and DDPED aqueous solutions were studied by surface tension measurements. The surface tension and critical micelle concentration (cmc) of DDPED is smaller than that of DTPTT. The DDPED can reduce the surface tension of water to approximate 34 mN m⁻¹ at concentration levels of 10⁻⁵ mol L⁻¹. The aggregation behavior of the DTPTT and DDPED aqueous solution were studied by dynamic light scattering and transmission electron microscopy. Both surfactants can form spherical vesicles at a solution of about 3–5 times cmc of the Gemini surfactants. The foam property was determined by nitrogen blowing method. The DTPTT has relatively good foaming ability and DDPED has excellent foam stability. The foam volume of DDPED barely change within 1000s. The emulsion stability of the Gemini surfactants was determined by separation time of water from the emulsion. The emulsion stability of DDPED is equivalent to Tween 80. The DDPED Gemini surfactant with two hydrophilic carboxylic groups has better surface activity, foam stability, and can be used as an O/W emulsifier.     

Synergistic Effects between Anionic and Sulfobetaine Surfactants for Stabilization of Foams Tolerant to Crude Oil in Foam Flooding

In foam flooding, foams stabilized by conventional surfactants are usually unstable in contacting with crude oil, which behaves as a strong defoaming agent. In this article, synergistic effects between different surfactants were utilized to improve foam stability against crude oil. Targeted to reservoir conditions of Daqing crude oil field, China (45 °C, salinity of 6778 mg L⁻¹, pH = 8–9), foams stabilized by typical anionic surfactants fatty alcohol polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) show low composite foam index (200–500 L s) and low oil tolerance index (0.1–0.2). However, the foam stability can be significantly improved by mixing the anionic surfactant with a sulfobetaine surfactant, which behaves as a foam stabilizer increasing the half-life of foams, and those with longer alkyl chain behave better. As an example, by mixing AES and SDS with hexadecyl dimethyl hydroxypropyl sulfobetaine (C₁₆HSB) at a molar fraction of 0.2 (referring to total surfactant, not including water), the maximum composite foaming index and oil tolerance index can be increased to 3000/5000 L s and 1.0/4.0, respectively, at a total concentration between 3 and 5 mM. The attractive interaction between the different surfactants in a mixed monolayer as reflected by the negative β^s parameter is responsible for the enhancement of the foam stabilization, which resulted in lower interfacial tensions and therefore negative enter (E), spreading (S), and bridging (B) coefficients of the oil. The oil is then emulsified as tiny droplets dispersed in lamellae, giving very stable pseudoemulsion films inhibiting rupture of the bubble films. This made it possible to utilize typical conventional anionic surfactants as foaming agents in foam flooding.