scholarly journals Effects of Chemical Dispersant on the Surface Properties of Kaolin and Aggregation with Spilled Oil

Author(s):  
Wenxin Li ◽  
Yue Yu ◽  
Deqi Xiong ◽  
Zhixin Qi ◽  
Sinan Fu ◽  
...  

Abstract After oil spills occur, dispersed oil droplets can collide with suspended particles in the water column to form the oil-mineral aggregate (OMA) and settle to the seafloor. However, only a few studies have concerned the effect of chemical dispersant on this process. In this paper, the mechanism by which dispersant affects the surface properties of kaolin as well as the viscosity and oil-seawater interfacial tension (IFTow) of Roncador crude oil were separately investigated by small scale tests. The results indicated that the presence of dispersant impairs the zeta potential and enhances the hydrophobicity of kaolin. The viscosity of Roncador crude oil rose slightly as the dosage of dispersant increased while IFTow decreased significantly. Furthermore, the oil dispersion and OMA formation at different dispersant-to-oil ratio (DOR) were evaluated in a wave tank. When DOR was less than 1:40, the oil enhancement of dispersant was not significant. In comparison, it began to contribute when DOR was over 1:40 and the effect became more pronounced with the increasing DOR. The adhesion between oil droplets and kaolin was inhibited with the increasing DOR. The size ratio between oil droplets and particles is the significant factor for OMA formation. The closer the oil-mineral size ratio is to 1, the more difficultly the OMA forms.

1977 ◽  
Vol 1977 (1) ◽  
pp. 387-390
Author(s):  
Gerard P. Canevari

ABSTRACT There has been an increasing awareness of the utility of conventional chemical dispersants in general, and self-mix dispersants in particular as a viable means to minimize damage from oil spills. This paper will update the use of, and activity regarding the self-mix dispersant as noted in applications over the past two years. In addition, those aspects that are still little understood are discussed. Specifically, uniformly sized, dispersed oil droplets of approximately 1 micron diameter are formed by the diffusion action of self-mix chemical dispersants. The droplet size influences the dilution rate of the spilled oil in field applications, and data to support this are presented. The results of laboratory bioassays performed with these much smaller dispersed oil droplets, as opposed to larger droplets formed with mechanical mixing, can be misinterpreted since the increased rate of dilution afforded by smaller droplet size is not replicated. In addition to the vital dilution study results, this paper also presents evidence to clarify several popular misconceptions regarding chemical dispersants. For example, it is explained that the apparent synergistic effects between oil and dispersant do not indicate that chemical dispersants release toxic substances from the oil into the water. Data is also presented which shows that dispersants do not cause the oil to sink.


2012 ◽  
Vol 608-609 ◽  
pp. 1387-1390
Author(s):  
Juan Sun ◽  
Dong Feng Zhao ◽  
Jing Sun ◽  
Chao Cheng Zhao

After oil spills in the coastal aquatic environment, the physical and chemical properties of the spilled oil may change under the influence of the chemical dispersant and form emulsions in the water. This paper presents the results of a laboratory study on the influence of chemical dispersant to the properties of crude oil. The experiments were conducted using two widely-used surfactant GM-2 and BH-X, two crude oil samples and artificial seawater. Density, viscosity and emulsification rate of crude oil with different amounts of dispersant added was measured. The results show that viscosity of the crude oil was highly influenced by the chemical dispersant. The maximum emulsification rate of the Saudi Arabian middle crude oil was 54.1% and 57.4% with the dispersant to oil ratio above 0.8, whereas the emulsification rate of the heavy oil was significantly lower than the middle oil with both of the two types of chemical dispersant.


2017 ◽  
Vol 118 (1-2) ◽  
pp. 275-280 ◽  
Author(s):  
Aiqin Wang ◽  
Yiming Li ◽  
Xiaolong Yang ◽  
Mutai Bao ◽  
Hua Cheng

1991 ◽  
Vol 1991 (1) ◽  
pp. 677-680 ◽  
Author(s):  
D.D. Evans ◽  
G.W. Mulholland ◽  
J.R. Lawson ◽  
E.J. Tennyson ◽  
M.F. Fingas ◽  
...  

ABSTRACT The Center for Fire Research (CFR) at the National Institute of Standards and Technology (NIST) is conducting research related to safety in offshore drilling and oil spill pollution under joint funding from Minerals Management Service (MMS), U.S. Coast Guard, and the American Petroleum Institute. Technical assistance in measurement has been donated by Environment Canada. This research has focused on examining the phenomena associated with crude oil combustion and the impact of using burning as a spill response method. The process of burning crude oil on water as a means to mitigate oil spills has been investigated with a research effort combining both small-scale experiments and calculations. As a result of these studies, there has been increased understanding of the burning process, including burning rate, heat radiation, smoke emission, smoke composition, and smoke dispersion in the atmosphere. A key to gaining acceptance of burning as a spill response technique is the demonstration that favorable results obtained at laboratory scale can be shown to continue in test burns representing the size of fires expected in actual operations. Field-scale burn tests are being planned and coordinated jointly by MMS, API, USCG, and Environment Canada to document the use of burning technology under conditions simulating actual oil spill cleanup operations. The purpose of this project is to measure the effects of oil spill burning in laboratory and field tests.


1981 ◽  
Vol 1981 (1) ◽  
pp. 263-268
Author(s):  
Joseph Buckley ◽  
David Green ◽  
Blair Humphrey

ABSTRACT Three experimental oil spills of 200, 400, and 200 litres (l) were conducted in October, 1978, in a semiprotected coastal area on Canada's west coast. The surface slicks were restrained with a Bennett inshore oil boom. The spilled oil was chemically dispersed using Corexit 9527, applied as a 10-percent solution in sea water and sprayed from a boat. The dispersed oil was monitored fluorometrically for some hours. Surface and dispersed oil were sampled for chemical analysis. The highest recorded concentration of dispersed oil was 1 part per million (ppm). After a short time (30 minutes), concentrations around 0.05 ppm were normal, decreasing to background within 5 hours. The concentrations were low compared to those expected for complete dispersion which, as visual observation confirmed, was not achieved. The dispersed oil did not mix deeper into the water column with the passage of time, in contrast to predicted behaviour and in spite of the lack of a significant vertical density gradient in the sea water. This was attributed to the buoyancy of the dispersed oil droplets and the limited vertical turbulence in the coastal locale of the experiment. The integrated quantity of oil in the water column decreased more rapidly than either the mean oil concentration of the cloud or the maximum concentration indicating that some of the dispersed oil was rising back to the surface. The surfacing of dispersed oil was confirmed visually during the experiment. The mixing action of the spray boat and breaker boards apparently created large oil droplets that did not form a stable dispersion. Horizontal diffusion of the dispersed oil was initially more rapid than expected, but the rate of spreading did not increase with time as predicted. The results imply that the scale of diffusion was larger than the scale of turbulence which again can be attributed to the locale of the experiment.


Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5733
Author(s):  
Kamila Haule ◽  
Henryk Toczek ◽  
Karolina Borzycka ◽  
Mirosław Darecki

Remote sensing techniques currently used to detect oil spills have not yet demonstrated their applicability to dispersed forms of oil. However, oil droplets dispersed in seawater are known to modify the local optical properties and, consequently, the upwelling light flux. Theoretically possible, passive remote detection of oil droplets was never tested in the offshore conditions. This study presents a field experiment which demonstrates the capability of commercially available sensors to detect significant changes in the remote sensing reflectance Rrs of seawater polluted by six types of dispersed oils (two crude oils, cylinder lubricant, biodiesel, and two marine gear lubricants). The experiment was based on the comparison of the upwelling radiance Lu measured in a transparent tank floating in full immersion in seawater in the Southern Baltic Sea. The tank was first filled with natural seawater and then polluted by dispersed oils in five consecutive concentrations of 1–15 ppm. After addition of dispersed oils, spectra of Rrs noticeably increased and the maximal increase varied from 40% to over three-fold at the highest oil droplet concentration. Moreover, the most affected Rrs band ratios and band differences were analyzed and are discussed in the context of future construction of algorithms for dispersed oil detection.


2014 ◽  
Vol 2014 (1) ◽  
pp. 1647-1658 ◽  
Author(s):  
Tim Wadsworth

ABSTRACT Experience has shown that the most time-consuming and costly component of a response to an oil spill is often the treatment or disposal of collected waste. The amount of waste generated is dependent on many factors, some which may be controlled more readily during the response. This paper analyses a number of important incidents as a result of which spilled oil affected shoreline resources with significant resultant clean-up effort. Spills of crude oil and of heavy fuel oil carried as cargo in tankers are reviewed to determine the types and volumes of waste generated and the clean-up methods undertaken to generate that waste. A comparison of the incidents will allow the most effective response methods to be determined, to show the techniques that generated the least volumes of waste. Data from DEEPWATER HORIZON is included to allow a discussion of the associated response. To achieve a practical comparison, the amount of waste is balanced against the amount of oil spilled to determine the oil:waste ratio. This ratio has evolved over many years into a long held guideline, used often for the purpose of contingency planning, that the amount of waste generated during an incident is approximately ten times the amount of oil spilled. This paper shows that with appropriate response actions, the guideline can be upheld.


Author(s):  
Joseph Katz ◽  
CJ Beegle-Krause ◽  
Michel Boufadel ◽  
Marcelo Chamecki ◽  
Vijay John ◽  
...  

Abstract A series of GOMRI-sponsored experimental and computational studies have discovered, elucidated and quantified the impact of small-scale processes on the dispersion, transport and weathering of crude oil slicks and subsurface plumes. Physical interfacial phenomena occurring at micron-scales include the formation of particle-stabilized emulsions, penetration of particles into oil droplets, formation of compound water-containing oil droplets during plume breakup, and the mechanisms affecting the breakup of oil into micro-droplet by tip streaming resulting from the drastic reduction in interfacial tension upon introduction of dispersant. Efforts aimed at development targeted delivery of surfactants have introduced solvent-free halloysite nanotubes that can be filled with surfactants, and preferentially released at oil-water interface. Buoyant surfactant-based gels, which enhance their encounter rates with oil slicks and adhere to weathered oil have also been developed. Studies of oil-bacteria interactions during early phases of biodegradation and shown how the bacteria, some highly active, attach to the oil-water interfaces and form complex films. Clay-decorated droplets sequester these bacteria and promote the propagation of these biofilm. Long extracellular polymeric substance (EPS) streamers generated by these biofilms form connected networks involving multiple droplets and debris, as well as increase the drag on the oil droplets. At 0.01–10 m scales, the generation of subsurface and airborne crude oil droplets by breaking waves, subsurface plumes and raindrop impact have been quantified. For waves, premixing the oil with dispersant reduces the droplets sizes to micron- and submicron-scales, and changes the slope of their size distribution. Without dispersant, the droplet diameters can be predicted based on the turbulence scales. With dispersant, the droplets are much smaller than the turbulence scales owing to the abovementioned tip-streaming. Aerosolization of oil is caused both by the initial splash and by subsequent bubble bursting, as entrained bubbles rise to the surface. Introduction of dispersant increases the airborne nano-droplet concentration by orders of magnitude, raising health questions. Dispersant injection also reduces the size of droplets in subsurface plumes, affecting the subsequent dispersion of these plume by currents and turbulence. Advancements have also been made in modeling of dissolution of oil in plumes, as well as in applications of Large Eddy Simulations (LES) to model plumes containing oil droplets and gas bubbles. The new multiscale framework, which accounts for the droplet size distribution and mass diffusion, can simulate the near- and far-fields of plumes, and predict the effect of vertical mixing promoted by turbulence on the transport of dispersed oil.


1995 ◽  
Vol 1995 (1) ◽  
pp. 1003-1004 ◽  
Author(s):  
Charles B. Pace ◽  
James R. Clark ◽  
Gail E. Bragin

ABSTRACT Standard aquatic toxicity tests do not address real-world, spiked exposure scenarios that occur during oil spills. We evaluated differences in toxicity of physically and chemically dispersed Kuwait crude oil to mysids (Mysidopsis bahia) under continuous and spiked (half-life of 2 hours) exposure conditions. The 96-hr LC50s for physically dispersed oil were 0.78 mg/L (continuous) and >2.9 mg/L (spiked), measured as total petroleum hydrocarbons (TPH). Values for chemically dispersed oil were 0.98 mg/L (continuous) and 17.7 mg/L (spiked) TPH. Continuous-exposure tests may overestimate the potential for toxic effects under real-world conditions by a factor of 18 or more.


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