The microwave absorption of emulsions containing aqueous micro- and nanodroplets: A means to optimize microwave heating

Holtze, Christian; Sivaramakrishnan, R.; Antonietti, Markus; Tsuwi, Julius; Kremer, Friedrich; Kramer, K.D.

doi:10.1016/j.jcis.2006.07.020

Cited by 24 publications

(15 citation statements)

References 20 publications

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“…The droplet size has been shown to affect the dielectric properties of emulsions. Holtze et al [3] reported a peak in dielectric properties for water-in-oil emulsions somewhere between 3.6µm and >10µm mean droplet diameter. Although more data would be required on the specific emulsions used in this study, it is possible that microwaves heat the lower water content emulsions more effectively due to their smaller droplet size.…”

Section: Separation Time Vs Water Contentmentioning

confidence: 99%

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Investigation into the mechanisms by which microwave heating enhances separation of water-in-oil emulsions

Binner

Robinson

Silvester

et al. 2014

Fuel

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(2014) Investigation into the mechanisms by which microwave heating enhances separation of water-in-oil emulsions. Fuel, 116 . pp. 516-521. ISSN 1873-7153 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/31942/1/130726_Manuscript%20revised_for%20archiving.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. ABSTRACTThe separation of water-in-oil emulsions made with Azeri crude was investigated using natural gravity settling and microwave heating techniques. Separation times could be reduced by an order of magnitude compared with untreated emulsions.Increasing the salinity of the water phase leads to a 15% average decrease in the settling time for untreated emulsions compared with over 90% for microwave-heatedemulsions. An image analysis technique showed that the observed increases in settling time could not be attributed to changes in viscosity alone. Significant coalescence of water droplets occurs during microwave heating, however the effects of coalescence and viscosity reduction cannot be completely decoupled. Despite this, it is clear that it is the thermal effect of microwave heating that leads to improvements in settling times, and that any advantages in microwave heating over conventional heating can Page 2 of 25 be explained by selective heating of the aqueous phase rather than so-called nonthermal effects. KEYWORDSWater-in-oil emulsion; microwave; coalescence; viscosity; interfacial tension; selective heating INTRODUCTIONEmulsions arise during the production of oil downstream from the well. Water is present with the oil, particularly in the latter stages of the well life when water injection is used to enhance the production rate. On leaving the well the mixture, at high pressure, is let down through a choke valve so that it can be further processed at moderate pressures. The pressure reduction valve creates significant shear within the fluid and it is this pressure drop that causes the emulsions to form. The water must be separated before further downstream transport and processing can commence, and as the oil and water phases are immiscible gravity separation can be utilised to separate the two substances. Gravity separation occurs due to a density difference between oil and water, and the separation of the two phases is governed by the settling velocity, u S . If u S is small then...

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Section: Separation Time Vs Water Contentmentioning

confidence: 99%

“…This reduces both the oil/water interfacial tension and viscosity of the oil [1,2]. Coalescence can be promoted by using chemical additives, which lower interfacial tension, or by applying a physical force to move the droplets together, which can be achieved using ultrasound or an electrostatic force [3]. There are several disadvantages with these methods;…”

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confidence: 99%

Investigation into the mechanisms by which microwave heating enhances separation of water-in-oil emulsions

Binner

Robinson

Silvester

et al. 2014

Fuel

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“…Coalescence can be promoted by using chemical additives, which lower interfacial tension, or by applying a physical force to move the droplets together, which can be achieved using ultrasound or an electrostatic force [5]. There are several disadvantages with these methods:…”

Section: Improving the Separation Of Water-in-oil Emulsions -Enhancinmentioning

confidence: 99%

“…Oil is microwave transparent compared with water, with a dielectric loss of two orders of magnitude smaller [6]. It has been shown that, with the exception of emulsions with very small water droplets (<256 nm), microwave heating will result in selective heating of the water when an oil water emulsion is exposed to a microwave field [5].…”

Section: Improving the Separation Of Water-in-oil Emulsions -Enhancinmentioning

confidence: 99%

Separation of Oil/Water Emulsions in Continuous Flow Using Microwave Heating

et al. 2013

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This work studies a continuous flow microwave system to enhance gravity settling of water-inoil emulsions. Settling times were found to be dependent upon the applied power, flowrate and energy input. Power and energy input are linked to liquid flowrate within the flow system used in this study, so a key objective of this work was to understand the effect of turbulence on the heating and separation of the flowing emulsion. At high flowrates (9 -12 L/min) it was found that turbulence dominates, with settling times largely independent of energy input. At lower flowrates (1 -6 L/min), when turbulence was decreased, it was found that the settling time decreased as the power density was increased. Settling times have the potential to be less than half that of untreated emulsions, and can be reduced further if turbulence can be minimised between the microwave heating zone and the settling zone in the process equipment.2

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“…The electromagnetic energy interact directly with the components of materials, the medium absorb the energy and convert it into heat (Mawioo et al, 2016). Considering the specific heat generation mechanisms of microwave irradiation, in real and complex medium, such as the wastewater, composition, dielectric properties of compounds, intermolecular interaction, chemical structure of molecules, physicochemical state, temperature, viscosity and density of continuous phase and their possible alteration during irradiation, furthermore the frequency of electromagnetic field has also effect on the thermal efficiency of heating (Holtze et al, 2006). Another interesting phenomenon of microwave irradiation is the selective heating.…”

Section: Introductionmentioning

confidence: 99%

Continuously flow microwave pre-treatment for enhanced anaerobic biodegradability of dairy industry sludge

Lemmer¹,

Hodúr²,

Beszédes³

2017

Agriculture Journal

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The microwave absorption of emulsions containing aqueous micro- and nanodroplets: A means to optimize microwave heating

Cited by 24 publications

References 20 publications

Investigation into the mechanisms by which microwave heating enhances separation of water-in-oil emulsions

Investigation into the mechanisms by which microwave heating enhances separation of water-in-oil emulsions

Separation of Oil/Water Emulsions in Continuous Flow Using Microwave Heating

Continuously flow microwave pre-treatment for enhanced anaerobic biodegradability of dairy industry sludge

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