SOME RECENT OBSERVATIONS REGARDING THE UNIQUE CHARACTERISTICS AND EFFECTIVENESS OF SELF-MIX CHEMICAL DISPERSANTS

1977 ◽  
Vol 1977 (1) ◽  
pp. 387-390
Author(s):  
Gerard P. Canevari
Keyword(s):  
Droplet Size ◽  
Oil Spills ◽  
Synergistic Effects ◽  
Toxic Substances ◽  
Mechanical Mixing ◽  
Oil Droplets ◽  
Dispersed Oil ◽  
Study Results ◽  
Micron Diameter ◽  
Spilled Oil

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.

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

2021 ◽  
Author(s):  
Wenxin Li ◽  
Yue Yu ◽  
Deqi Xiong ◽  
Zhixin Qi ◽  
Sinan Fu ◽  
...  
Keyword(s):  
Crude Oil ◽  
Surface Properties ◽  
Oil Spills ◽  
Size Ratio ◽  
Small Scale ◽  
Oil Droplets ◽  
Mineral Aggregate ◽  
Chemical Dispersant ◽  
Dispersed Oil ◽  
Spilled Oil

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.

Ultrasonic Scattering Measurements of Dispersed Oil Droplets in the Presence of Gas

2014 ◽  
Vol 2014 (1) ◽  
pp. 266-282 ◽  
Author(s):  
Paul D. Panetta ◽  
Dale McElhone ◽  
Kyle Winfield ◽  
Grace Cartwright
Keyword(s):  
Natural Gas ◽  
Water Column ◽  
Droplet Size ◽  
Oil Spills ◽  
Acoustic Scattering ◽  
Gas Bubbles ◽  
Deepwater Horizon ◽  
Oil Droplets ◽  
Large Wave ◽  
Dispersed Oil

ABSTRACT To help minimize the effects of oil spills on marine environments, chemical dispersants are used to disperse the oil in the water column so the oil can be consumed by naturally occurring bacteria. During the Deepwater Horizon incident, 1.1 million gallons of dispersant were injected directly into the flowing plume of oil and natural gas over 1500 meters deep. Dispersant's main effect is to decrease the surface tension at the oil-water interface causing the oil to form droplets smaller than ~70 microns so they can remain in the water column. Currently the efficacy of aerial applied dispersants on surface slicks is determined by measuring the droplet size decrease using a Laser In-Situ Scattering Transmissometer (LISST) or by detecting the oil in the water column using fluorometers. LISST instruments are limited to dilute mixtures, below ~500 ppm, because the LISST signal saturates for concentrated mixtures, and their windows can become occluded by oil and biofilms. Fluorometers only measure oil concentration; thus they cannot distinguish between naturally dispersed oil droplets, which can float back to the surface, from chemically dispersed oil droplets, which will remain in the water column to be naturally biodegraded. When gas is present as was the case in the Deepwater Horizon incident where it was estimated that the plume consisted of ~22% natural gas, the LISST cannot distinguish between oil droplets and gas bubbles and thus is not able to track the effectiveness of dispersants in the presence of gas. Acoustic measurements overcome the problems associated with the LISST and fluorometers and are ideal for applications subsurface near a blowout and for low ppm levels expected for surface slicks. One of the key features of the sound wave propagating through the water is the scattering at the interface between the water and object. In previous work we showed the proof of concept to measure the average oil droplet size using acoustic. We used the resonance behavior of the gas bubbles to identify them and separate their contribution to the measured acoustic scattering for various oil and dispersant combinations . We developed acoustic scattering and resonance measurements to track the size of oil droplets in the presence of gas during subsurface releases at SINTEF and in Ohmsett's large wave tank.

OIL SPILL CLEANUP WITH DISPERSANTS: A BOOMED OIL SPILL EXPERIMENT

1981 ◽  
Vol 1981 (1) ◽  
pp. 263-268
Author(s):  
Joseph Buckley ◽  
David Green ◽  
Blair Humphrey
Keyword(s):  
Water Column ◽  
Oil Spill ◽  
Oil Spills ◽  
Sea Water ◽  
Visual Observation ◽  
Oil Droplets ◽  
Oil Boom ◽  
Dispersed Oil ◽  
Vertical Density ◽  
Oil Spill Cleanup

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.

scholarly journals Influence of Dispersed Oil on the Remote Sensing Reflectance—Field Experiment in the Baltic Sea

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5733
Author(s):  
Kamila Haule ◽  
Henryk Toczek ◽  
Karolina Borzycka ◽  
Mirosław Darecki
Keyword(s):  
Remote Sensing ◽  
Field Experiment ◽  
Baltic Sea ◽  
Oil Spills ◽  
Light Flux ◽  
Natural Seawater ◽  
Oil Droplets ◽  
Maximal Increase ◽  
Remote Sensing Reflectance ◽  
Dispersed Oil

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.

The Fate of Dispersed Oil Under Ice: Results of JIP Phase 1 Program

2014 ◽  
Vol 2014 (1) ◽  
pp. 949-959
Author(s):  
CJ Beegle-Krause ◽  
Miles McPhee ◽  
Harper Simmons ◽  
Ragnhild Lundmark Daae ◽  
Mark Reed
Keyword(s):  
Literature Review ◽  
Water Column ◽  
Droplet Size ◽  
Fluorescent Dyes ◽  
Autonomous Underwater Vehicles ◽  
The Arctic ◽  
Formation Mechanisms ◽  
Oil Droplets ◽  
Mixing Energy ◽  
Dispersed Oil

ABSTRACT Ice infested waters pose unique challenges to preparedness and response for potential oil spills. An international team of researchers are working together to create a model to aid in evaluating use of dispersants in ice. The model will be designed to evaluate whether or not dispersed oil droplets formed under continuous or concentrated ice could resurface under the ice to form a significant accumulation within two days. The goal is to develop a tool to support contingency planning decisions with respect to dispersant use. Phase I of the project was to perform a literature review to develop recommendations to fill data gaps in the ice, current, and turbulence data needed to run a model. Phase II will include field work to collect data and model development and testing. The model will require information about the oil and dispersed oil droplet size distribution and water column information to predict mixing energy that could keep the oil droplets suspended. Droplet size distributions can be easily measured. The challenge is to provide representative information about the water column. We are evaluating several types of oceanographic observational technologies to collect data on under ice mixing energy such as fluorescent dyes, Turbulent Instrument Clusters (TICs), Autonomous Underwater Vehicles (UAVs), and Acoustic Doppler Current Profilers (ADCPs). From our review, we expect to be able to collect the required environmental parameters within reasonable cost and time. There are a variety of ice formation mechanisms and ice types in the Arctic and Antarctic. Bottom roughness and ice concentration play keys rolls controlling the amount of mixing energy available under the ice. Heavier ice concentrations absorb surface wave energy, which provides the mixing energy for open water dispersant operations. The literature review indicates that good measurements and a good turbulence closure model are key to obtaining good predictions. We are interested in feedback from the IOSC audience regarding our vision of framing the predictive model as an appropriate decision support tool for the Planning and Response Communities.

A REVIEW OF THE UTILITY OF SELF-MIXING DISPERSANTS IN RECENT YEARS

1975 ◽  
Vol 1975 (1) ◽  
pp. 337-342
Author(s):  
Gerard P. Canevari
Keyword(s):  
Droplet Size ◽  
Oil Spills ◽  
Objective Assessment ◽  
Ecological Impact ◽  
Large Body ◽  
Mixing Energy ◽  
Dispersed Oil ◽  
Actual Field ◽  
The Impact

ABSTRACT This paper reviews the development during the past two years of self-mixing chemical dispersants to minimize damage from oil spills. Some history regarding the acceptance (or lack thereof) of previous conventional dispersants requiring mixing energy is covered so that the progress manifested by the current self-mix dispersant approach can be readily appreciated. The utility of the self-mix dispersant system is based upon both the elimination of the laborious mixing requirement and the formation of submicron diameter size oil droplets. The role of droplet size in the behavior and movement of dispersed oil as well as the effect of droplet size on the toxicological and ecological impact of the dispersed oil, are significant aspects that are discussed. The planned research to determine the fate of dispersed oil under actual field conditions is outlined. This will permit a more accurate and objective assessment of the impact of dispersed oil on the marine environment than is now available from the extrapolation of laboratory bioassays. For example, the rapid dilution-dispersion of the oil into a large body of water is an important characteristic and advantage of the chemical dispersion process and is very much influenced by droplet size. However, in laboratory tests the concentration of the oil is maintained at a constant level during the test exposure, and little attention is directed toward the determination or control of the dispersed oil droplet size.

EFFECTS OF OIL AND CHEMICALLY DISPERSED OIL IN THE ENVIRONMENT

2001 ◽  
Vol 2001 (2) ◽  
pp. 1213-1216 ◽  
Author(s):  
John N. Boyd ◽  
Debra Scholz ◽  
Ann Hayward Walker
Keyword(s):  
Technical Information ◽  
American Petroleum Institute ◽  
Scientific Language ◽  
Dispersed Oil ◽  
Study Results ◽  
Chemically Dispersed Oil ◽  
1960S And 1970S ◽  
The 1960S ◽  
Spilled Oil ◽  
The Way

ABSTRACT This paper describes the last phase of a project sponsored by the American Petroleum Institute (API). Using risk communication methodologies, this project was designed to produce three dispersant issue papers as unbiased reference sources that present technical information and study results in non-scientific language for the layman. The third issue paper, currently in press, was designed to provide the decision maker and layman with an understanding of how spilled oil and chemically dispersed oil affect resources in the environment. Synopses of key sections of this paper are presented here. Understanding exposure and effects is a complex task. Exposure to oil alone can cause a variety of adverse effects, including slowed growth, reduced reproduction, and death. Adding dispersants to spilled oil will change the way resources are affected. Today's dispersants are mixtures of solvents and surfactants and, although they can be toxic, are less dangerous than the dispersant products used in the 1960s and 1970s. How the addition of chemical dispersants to spilled oil will change the way resources are impacted has been a difficult question to answer. Decision makers need to understand several concepts to evaluate how different resources will be affected by oil and chemically dispersed oil during a spill. These include understanding toxicity, what the different routes of exposure are for an organism, how resources from different areas (e.g., water column, water surface, bottom dwelling, or intertidal areas) typically are affected by oil exposure, and how the addition of dispersants changes their exposure to oil. These topics are addressed in this paper.

Subsea Release of Oil & Gas – A Downscaled Laboratory Study Focused on Initial Droplet Formation and the Effect of Dispersant Injection

2014 ◽  
Vol 2014 (1) ◽  
pp. 283-298
Author(s):  
Per Johan Brandvik ◽  
Øistein Johansen ◽  
Umer Farooq
Keyword(s):  
Droplet Size ◽  
Sea Water ◽  
Droplet Formation ◽  
Size Distributions ◽  
Oil Droplets ◽  
Substantial Impact ◽  
Dispersed Oil ◽  
Laboratory Facility ◽  
Injection Techniques ◽  
Droplet Sizes

ABSTRACT This article describes the SINTEF Tower Basin (located in Trondheim, Norway) and its use for examining droplet formation and the effectiveness of dispersant injection. The Tower Basin is 6 m high and 3 m in diameter, containing 42 m3 of natural sea water. Oil is injected from the base of the basin and oil droplets are monitored by laser diffraction and in-situ camera techniques. Size distributions of oil droplets formed in deep water oil & gas blowouts have a substantial impact on the fate of the oil in the environment. However, very limited data on droplet size distributions from subsurface releases exist. The objective of this study has been to establish a laboratory facility to examine droplet size versus release conditions (flow rates and nozzle diameters), oil properties and injection of dispersants (injection techniques and dispersant types). Changes in the size of oil droplets that result from injection of dispersant are used to assess the effectiveness of the dispersant application (dosage and injection method). This comprehensive dataset is used to develop and calibrate existing algorithms to predict droplet sizes from subsurface releases, and the effect of dispersant treatment. The improved algorithms are implemented in current operational models where they are used to describe subsurface use of dispersant and fate of the dispersed oil in the water column.

scholarly journals Visual Appearance of Oil on the Sea

2021 ◽  
Vol 9 (1) ◽  
pp. 97
Author(s):  
Merv Fingas
Keyword(s):  
Water Surface ◽  
Oil Spills ◽  
Discharge Rate ◽  
Physical Explanation ◽  
Visual Appearance ◽  
Oil In Water ◽  
Other Information ◽  
Surface Discharges ◽  
Oil Emulsions ◽  
Spilled Oil

The visual appearance of oil spills at sea is often used as an indicator of spilled oil properties, state and slick thickness. These appearances and the oil properties that are associated with them are reviewed in this paper. The appearance of oil spills is an estimator of thickness of thin oil slicks, thinner than a rainbow sheen (<3 µm). Rainbow sheens have a strong physical explanation. Thicker oil slicks (e.g., >3 µm) are not correlated with a given oil appearance. At one time, the appearance of surface discharges from ships was thought to be correlated with discharge rate and vessel speed; however, this approach is now known to be incorrect. Oil on the sea can sometimes form water-in-oil emulsions, dependent on the properties of the oil, and these are often reddish in color. These can be detected visually, providing useful information on the state of the oil. Oil-in-water emulsions can be seen as a coffee-colored cloud below the water surface. Other information gleaned from the oil appearance includes coverage and distribution on the surface.

Sign in / Sign up

Export Citation Format

Share Document