Spreading of aqueous solutions of a mixture of fluoro- and hydrocarbon surfactants on liquid hydrocarbon substrates

Jho, C

doi:10.1016/0021-9797(87)90176-7

Cited by 18 publications

(12 citation statements)

References 11 publications

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“…In addition to repelling water, the hydrophobic part of the fluorinated surfactant also repels hydrocarbon liquids and oils; that is, it possesses the lipophobic properties. In effect, the perfluorinated end positions itself in the air within a three-phase air-water-oil system, facilitating the formation of thin (~20 µm in thickness) films that spread rapidly on hydrocarbon surfaces [3]. Unfortunately, concerns have been raised about the health effects of the degradation products of fluorosurfactants in the environment.…”

Section: Introductionmentioning

confidence: 99%

“…We also restrict ourselves to perform measurements of the dynamic tension at time scale longer than 1 s, as we suspect that FF solutions would display a slower approach to equilibrium than AFFF formulations and wish to generate the data that would be useful for modelling the effect of dynamic surface and interfacial tension on flow, drainage and coarsening of FF foams. The characteristic time for film spreading of AFFF films is in the order of 0.1 to 1 s [3], whereas fire fighting foam formulations exhibit a characteristic time for foam flow (as opposed to film flow), drainage and coarsening of between 10 and 600 s [2]. Until present, the dynamic surface and interfacial tension has not been included in modelling of these phenomena in the context of fire fighting foams [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Surface And Interfacial Tension Of Afff And Fluorine-free Class B Foam Solutions

Dlugogorski¹,

Phiyanalinmat²,

Kennedy³

2005

Fire Safety Science - Proceedings of the Eigth International Sy

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This paper investigates the dynamic surface tension of aqueous film forming (AFFF) and fluorine-free (FF) foam solutions by pendant drop tensiometry. Additional experiments are conducted to measure the interfacial tension between the foam solutions and two hydrocarbon liquids, n-heptane and diesel oil. The pendant drop technique yields both surface and interfacial tension at time scales ranging from seconds to hours, being limited at the lower end by the time necessary to form a droplet, and at the upper end by the evaporation of the droplet's material. The results indicate that the surface tension of AFFF formulations, diluted at the design concentration, rapidly reaches its equilibrium value. However, the approach to equilibrium is slowed down by additives, such as xanthan gum, present in the alcohol tolerant concentrates (ATC-AFFF). FF solutions show a slower approach to static values than AFFF formulations. At the design dilution, and at room temperature, these static values are in the order of 27 mN m -1 , as compared to 16 mN m -1 for AFFF solutions. The measurements of the interfacial tension indicate rapid attainment of equilibrium for both AFFF and FF formulations, with the static values of around 2 and 0.9-2.5 mN m -1 , for AFFF and FF, respectively. With the surface tension of n-heptane and diesel oil of 20.1 and 28.3 mN m -1 , the spreading coefficient of FF formulations for the present systems varies between -9.4 and 0.6 mN m -1 . These results indicate that film formation does not play a role during fire suppression by FF foams.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamic Surface And Interfacial Tension Of Afff And Fluorine-free Class B Foam Solutions

Dlugogorski¹,

Phiyanalinmat²,

Kennedy³

2005

Fire Safety Science - Proceedings of the Eigth International Sy

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“…In the case of the formation of an aqueous film on the surface of hydrocarbons, the change in free energy is due to a decrease in interfacial energy in system "hydrocarbon -aqueous solution -phase boundary -film -hydrocarbon". If we do not take into account the thickness of the aqueous film in film-hydrocarbon system, then changing the surface energy of a system can be expressed as a difference corresponding to the values of the interracial tension and the phase boundary between the film and the hydrocarbon, according to a known formula, and estimated upon the value of fσ(01) -spreading of solution on hydrocarbon coefficient [5][6][7][8][9]:…”

Section: Methodsmentioning

confidence: 99%

“…The purpose of this work is to develop a classification of foaming agents dedicated for extinguishing fires of petroleum products due to spreading of the aqueous solution on hydrocarbon surface coefficient, based on complex investigational studies of foam extinguishing effectiveness and surface activity at the junction with a hydrocarbon [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

New classification of foaming agents for fire extinguishing

Degaev

2018

MATEC Web Conf.

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Abstract. Extinguishing fires of petroleum products during emergency spill at industrial facilities of capital construction, transport, gas stations and the destruction of oil tanks is most effective when using foamers. Classification of foaming agents intended for extinguishing of fires of oil products, which is based on the structure of spreading coefficient of water foam-forming solution over hydrocarbon surface is presented. Results of experimental studies using various foaming agents with different structure of spreading coefficient are given. It is determined which of homologs of a number of sodium primary alkylsulfates differ in foaming capacity and fire extinguishing efficiency. It is revealed that decrease of interfacial tension value leads to reduction of extinguishing time of a heptane flame.

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“…Special focus on fire extinguishing by supplying foam into the tank's base is explained by low reliability of foam supply systems with supply from above, from foam generators installed on the upper edge of the tank wall, because when the vapor-air mix explodes inside the tank, it compromises integrity of suspended structures, and no foam can get into the tank [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Improving Fire Protection of Pontoon Tanks or Floating Roof Tanks

Degaev

Korolchenko

2017

MATEC Web Conf.

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Abstract:The paper presents research of new solutions to improve fire protection of pontoon tanks or floating roof tanks. Extinguishing efficiency of the subsurface supply system is boosted by a different configuration of the pontoon or floating roof, and also with a cooling system used for oil product evacuation. Efficiency of the proposed methods is more than doubled compared to the existing subsurface extinguishing method.

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Spreading of aqueous solutions of a mixture of fluoro- and hydrocarbon surfactants on liquid hydrocarbon substrates

Cited by 18 publications

References 11 publications

Dynamic Surface And Interfacial Tension Of Afff And Fluorine-free Class B Foam Solutions

Dynamic Surface And Interfacial Tension Of Afff And Fluorine-free Class B Foam Solutions

New classification of foaming agents for fire extinguishing

Improving Fire Protection of Pontoon Tanks or Floating Roof Tanks

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