Dewatering of crude oil emulsions 3. Emulsion resolution by chemical means

Mohammed, Rasha A.; Bailey, A.I.; Luckham, P.F.; Taylor, Spencer E.

doi:10.1016/0927-7757(93)02706-k

Cited by 119 publications

(49 citation statements)

References 7 publications

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“…The high viscosity of the emulsion prevented pure bacterial isolates from causing significant deemulsification by N. amarae or R. rhodochrous (667). Elevating the temperature, which reduces apparent viscosity, generally accelerates deemulsification (344,430). Microbial deemulsification with a mixed bacterial culture was highest at 50°C (449).…”

Section: Microbial Deemulsificationmentioning

confidence: 99%

Recent Advances in Petroleum Microbiology

Hamme¹,

Singh

Ward

2003

Microbiol Mol Biol Rev

1,201

640

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Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times (<60 s) are being used effectively. Microbes are being injected into partially spent petroleum reservoirs to enhance oil recovery. However, these microbial processes have not exhibited consistent and effective performance, primarily because of our inability to control conditions in the subsurface environment. Microbes may be exploited to break stable oilfield emulsions to produce pipeline quality oil. There is interest in replacing physical oil desulfurization processes with biodesulfurization methods through promotion of selective sulfur removal without degradation of associated carbon moieties. However, since microbes require an environment containing some water, a two-phase oil-water system must be established to optimize contact between the microbes and the hydrocarbon, and such an emulsion is not easily created with viscous crude oil. This challenge may be circumvented by application of the technology to more refined gasoline and diesel substrates, where aqueous-hydrocarbon emulsions are more easily generated. Molecular approaches are being used to broaden the substrate specificity and increase the rates and extents of desulfurization. Bacterial processes are being commercialized for removal of H2S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments

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Section: Microbial Deemulsificationmentioning

confidence: 99%

Recent Advances in Petroleum Microbiology

Hamme¹,

Singh

Ward

2003

Microbiol Mol Biol Rev

1,201

640

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“…It was established that beyond an optimal dosage, the performance of a demulsifier can either plateau (type I behaviour) or degrade (type II behaviour, also known as overdose), resulting in an increase in the emulsion stability. Type I behaviour has been reported for EC 31 and for some EO-PO demulsifiers 27,[32][33][34] , while overdose was observed for octylphenylpolyethoxylates and sodium bis(2-ethylhexyl)sulfosuccinate demulsifiers 35 , commercial demulsifiers [36][37][38] , polyoxyalkylates 9 , diethanolamines 15 and some EO-PO demulsifiers 27,39 . These demulsifiers act either as flocculants or coalescers 41 .…”

Section: Introductionmentioning

confidence: 99%

Demulsification Mechanism of Asphaltene-Stabilized Water-in-Oil Emulsions by a Polymeric Ethylene Oxide–Propylene Oxide Demulsifier

et al. 2014

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The demulsification mechanism of asphaltene stabilized water-in-toluene emulsions by an ethylene-oxide/propylene oxide (EO/PO) based polymeric demulsifier was studied.Demulsification efficiency was determined by bottle tests and correlated to the physicochemical properties of asphaltene interfacial films after demulsifier addition. From bottle tests and droplet coalescence experiments, the demulsifier showed an optimal performance at 2.3 ppm (mass basis) in toluene. At high concentrations, the demulsification performance deteriorated due to the intrinsic stabilizing capacity of the demulsifier, which was attributed to steric repulsion between water droplets. Addition of demulsifier was shown to soften the asphaltene film under (i.e. reduce the viscoelastic moduli of asphaltene films) both shear and compressional interfacial deformations. Study of the micro and macro structure, and the chemical composition of asphaltene film at the toluene-water interface after demulsifier addition demonstrated gradual penetration of the demulsifier into the asphaltene film. Demulsifier penetration in the asphaltene film changed the asphaltene interfacial mobility and morphology, as probed with Brewster Angle and Atomic Force Microscopy.

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“…Water droplets can be removed from a continuous oil phase by several methods [12], such as chemical demulsifiers [13,14], gravity or centrifugal separation [15,16], pH adjustment and heating treatment [12,17] and membrane filtration separation [12,15]. However, nowadays one of the most effective and utilized method from viewpoint of energy efficiency is electrostatic demulsification.…”

Section: Introductionmentioning

confidence: 99%

Electro-coalescence of water drops in oils under pulsatile electric fields

Mousavi

Ghadiri

Buckley

2014

Chemical Engineering Science

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For the separation of disperesed water drops from oils an electric field may be used to enhance their coalescence. However, this process could cause some undesirable phenomena such as secondary droplets formation, reducing the separation efficiency. Here the effect of pulsatile electric fields (PEF) on the secondary droplets formation has been investigated. In the presence of a very low frequency PEF or DC electric field three distinct drop-drop and drop-interface interaction patterns are observed: complete coalescence, partial coalescence and rebound without coalescence. The first is the ideal pattern not leaving any secondary droplets. It has previously been shown that an increase in the electric field strength and/or a decrease in the interfacial tension result in non-ideal patterns in dropinterface coalescence. The application of PEF shifts the coalscence pattern from a non-ideal to an ideal one in both drop-drop and drop-interface coalescences. Three waveform types, i.e. square, sinusoidal and sawtooth waves have been applied to the coalescence process. It is shown that the sawtooth waveform is the most effective in reducing the secondary droplets formation in dropinterface coalescence, followed closely by the sinusoidal one. The observation of videos sequences suggests that a threshold frequency exists above which a non-ideal pattern switches to an ideal one. For drop-drop coalescence this threshold frequency depends on the PEF amplitude and the size of primary drop pairs, as for bigger primary drop pairs and larger amplitudes of PEF the threshold frequency would be higher. When using pulsatile electric fields higher field strengths can be applied for systems having a high water content without causing field breakdown, as compared to constant DC field. This is useful in optimizing the electro-coalescence process.

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Dewatering of crude oil emulsions 3. Emulsion resolution by chemical means

Cited by 119 publications

References 7 publications

Recent Advances in Petroleum Microbiology

Recent Advances in Petroleum Microbiology

Demulsification Mechanism of Asphaltene-Stabilized Water-in-Oil Emulsions by a Polymeric Ethylene Oxide–Propylene Oxide Demulsifier

Electro-coalescence of water drops in oils under pulsatile electric fields

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