39 results on '"Boufadel, Michel C."'
Search Results
2. Flow Dynamics in Eccentrically Rotating Flasks Used for Dispersant Effectiveness Testing
- Author
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Kaku, Vikram J., Boufadel, Michel C., Venosa, Albert D., and Weaver, James
- Published
- 2006
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3. Experimental Investigation of Oil Droplet Size Distribution in Underwater Oil and Oil-Air Jet.
- Author
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Ruixue Liu, Daskiran, Cosan, Fangda Cui, Wen Ji, Lin Zhao, Robinson, Brian, King, Thomas, Lee, Kenneth, and Boufadel, Michel C.
- Subjects
PETROLEUM distribution ,OIL spills ,DISPERSING agents ,HYDRODYNAMICS - Abstract
Understanding the droplet size distribution of subsea oil releasing is important to predict the subsequent transport and degradation of the spilled oil. Single- and multi-phase oil jet experiments were conducted in the Ohmsett facility, including pure oil jet and oil-air jet through a 10.7-mm pipe and a 4.7-mm pipe. Measurements of the vertical jet hydrodynamics and the oil size distribution were obtained. The reported results help to extend subsea oil spills experiment scale into a meso-scale, and the measurement range of the oil size is widened up to 2 cm. Moreover, the application of dispersant and involvement of air phase provided valuable scientific evidence for the usage of dispersants to treat oil spills. The data confirmed the effectiveness of the dispersant that reduces oil droplet size and also suggested that the participation of the gas phase facilitated the decreasing of oil droplet size. The results were compared to the numerical simulation tool VDROP-J. While the hydrodynamics showed good consistency, the systemdependent coefficient needed a slight revision to coincide with presented data. This also confirmed the significance of experimental materials for further validation and development of oil spill models, where we also provided guidance and discussion on conducting and post-processing the oil spill experiment. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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4. Dispersants as marine oil spill treating agents: a review on mesoscale tests and field trials.
- Author
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Merlin, Francois, Zhu, Zhiwen, Yang, Min, Chen, Bing, Lee, Kenneth, Boufadel, Michel C., Isaacman, Lisa, and Zhang, Baiyu
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OIL spills ,DISPERSING agents ,KNOWLEDGE gap theory ,PUBLIC opinion - Abstract
The increasing oil demand and busy waterways highlight the importance of oil spill preparedness and responses. Dispersants attract attention as an effective response tool to manage the impacts of major spill incidents. Despite in-depth laboratory evaluations on the effectiveness of chemical dispersants and their impacts on the transportation and fate of spilled oils, how dispersant works at sea remains a question and calls for the tests with greater realism to validate laboratory results, bring in energy impacts, and evaluate dispersant application equipment. Mesoscale studies and field trials have thus been widely conducted to assist better spill response operations. Such research attempts, however, lack a systematic summary. This study tried to fill the knowledge gaps by introducing the mesoscale facilities developed to advance the understanding of dispersant effectiveness on various sea conditions. An up-to-date overview of mesoscale studies and field trial assessments of dispersant effectiveness has also been conducted. We ended this review by highlighting the importance of public perception and future research needs to promote the approval and application of dispersants in spill incidents. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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5. Modeling oil dispersion under breaking waves. Part II: Coupling Lagrangian particle tracking with population balance model.
- Author
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Cui, Fangda, Zhao, Lin, Daskiran, Cosan, King, Thomas, Lee, Kenneth, Katz, Joseph, and Boufadel, Michel C.
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PETROLEUM ,INTERFACIAL tension ,OIL spills ,DISPERSION (Chemistry) ,WATER waves - Abstract
Oil dispersion under a deep-water plunging breaker of height 0.15 m was studied by coupling the Lagrangian particle tracking code (NEMO3D) with the population balance model (VDROP). The wave hydrodynamics obtained in Part I (Cui et al. in Environ Fluid Mech 2020 (in press)) was used as input. It was observed that droplet inertia and major forces on droplets significantly impacted the transport of oil droplets under wave conditions, and neglecting it caused less entrainment into the water column and horizontal spread of oil plume. For droplets less than 400 microns, the droplet size distribution (DSD) tended to follow a power-law distribution with an exponent close to − 2.3, which was consistent with earlier experimental observations by Delvigne and Sweeney (Oil Chem Pollut 4(4):281–310, 1988). The distribution of large size droplets evolved with time and showed agreement with a power-law distribution having an exponent of − 9.7 about 20 s after the passage of the wave train. Reducing the interfacial tension enhanced droplets breakup and increased the exponent of power-law distribution to − 6.1 for droplets smaller than 400 microns. It was also found that neglecting the vertical gradient of eddy diffusivity led to the accumulation of oil droplets in low eddy diffusivity regions at the bottom part of the wave breaker. The investigation herein could be used to obtain design values for breakers that could be used in oil spill models to predict the oil droplet size distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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6. Bacteria forming drag-increasing streamers on a drop implicates complementary fates of rising deep-sea oil droplets.
- Author
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White, Andrew R., Jalali, Maryam, Boufadel, Michel C., and Sheng, Jian
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OIL-water interfaces ,BIODEGRADATION ,MICROCOSM & macrocosm ,MICROFLUIDICS ,OIL spills - Abstract
Competing time scales involved in rapid rising micro-droplets in comparison to substantially slower biodegradation processes at oil-water interfaces highlights a perplexing question: how do biotic processes occur and alter the fates of oil micro-droplets (<500 μm) in the 400 m thick Deepwater Horizon deep-sea plume? For instance, a 200 μm droplet traverses the plume in ~48 h, while known biodegradation processes require weeks to complete. Using a microfluidic platform allowing microcosm observations of a droplet passing through a bacterial suspension at ecologically relevant length and time scales, we discover that within minutes bacteria attach onto an oil droplet and extrude polymeric streamers that rapidly bundle into an elongated aggregate, drastically increasing drag that consequently slows droplet rising velocity. Results provide a key mechanism bridging competing scales and establish a potential pathway to biodegradation and sedimentations as well as substantially alter physical transport of droplets during a deep-sea oil spill with dispersant. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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7. The treatment of biodegradation in models of sub-surface oil spills: A review and sensitivity study.
- Author
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Socolofsky, Scott A., Gros, Jonas, North, Elizabeth, Boufadel, Michel C., Parkerton, Thomas F., and Adams, E. Eric
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OIL spills ,DECAY constants ,PETROLEUM - Abstract
Biodegradation is important for the fate of oil spilled in marine environments, yet parameterization of biodegradation varies across oil spill models, which usually apply constant first-order decay rates to multiple pseudo-components describing an oil. To understand the influence of model parameterization on the fate of subsurface oil droplets, we reviewed existing algorithms and rates and conducted a model sensitivity study. Droplets were simulated from a blowout at 2000 m depth and were either treated with sub-surface dispersant injection (2% dispersant to oil ratio) or untreated. The most important factor affecting oil fate was the size of the droplets, with biodegradation contributing substantially to the fate of droplets ≤0.5 mm. Oil types, which were similar, had limited influence on simulated oil fate. Model results suggest that knowledge of droplet sizes and improved estimation of pseudo-component biodegradation rates and lag times would enhance prediction of the fate and transport of subsurface oil. • Biodegradation is a critical process that governs the fate of oil spilled subsea. • Current models use first-order decay of pseudo-components of the oil composition. • We simulated subsea oil spills varying composition, biodegradation rates, and droplet size. • The most important parameter affecting surfacing time and location was droplet size. • The choice of biodegradation model and rates was of secondary importance. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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8. On the transport and modeling of dispersed oil under ice.
- Author
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Boufadel, Michel C., Cui, Fangda, Katz, Joseph, Nedwed, Tim, and Lee, Kenneth
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OIL spills ,DROPLETS ,VELOCITY ,HYDRODYNAMICS ,DIFFUSION ,BOUNDARY layer (Aerodynamics) - Abstract
Abstract Theoretical arguments and numerical investigations were conducted to understand the transport of oil droplets under ice. It was found that the boundary layer (BL) in the water under ice produces a downward velocity that reaches up to 0.2% of horizontal current speed, and is, in general, larger than the rise velocity of 70 μm oil droplets. The eddy diffusivity was found to increase with depth and to decrease gradually afterward. Neglecting the gradient of eddy diffusivity when conducting Lagrangian transport of oil droplets would result in an unphysical spatial distribution. When the downward velocity of water was neglected, oil accumulated at the water-ice interface regardless of the attachment efficiency. The lift force was found to scrape off droplets of the ice, especially for droplets ≤ 70 μm. These findings suggest that previous oil spill simulations may have overestimated the number of small droplets (≤70 μm) at the water-ice interface. Highlights • A downward water velocity occurs under the ice due to boundary layer (BL) hydrodynamics. • The gradient of eddy diffusivity needs to be considered in Lagrangian oil spill models. • Lift at the ice-water interface could scrape off oil droplets of the ice. • The findings suggest existing approaches overestimate the amount of small oil droplet (< 70 μm) at the water-ice interface. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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9. Field fluorometers for assessing oil dispersion at sea.
- Author
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Abou-Khalil, Charbel, Ji, Wen, Prince, Roger C., Coelho, Gina M., Nedwed, Tim J., Lee, Kenneth, and Boufadel, Michel C.
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AERIAL spraying & dusting in agriculture ,PETROLEUM ,DISPERSING agents ,DISPERSION (Chemistry) ,OIL spills ,COASTAL surveillance - Abstract
Oil dispersion by the application of chemical dispersants is an important tool in oil spill response, but it is difficult to quantify in the field in a timely fashion that is useful for coordinators and decision-makers. One option is the use of rugged portable field fluorometers that can deliver essentially instantaneous results if access is attainable. The United States Coast Guard has suggested, in their Special Monitoring of Applied Response Technologies (SMART) protocols, that successful oil dispersion can be identified by a five-fold increase in oil fluorescence. Here we test three commercial fluorometers with different excitation/emission windows (SeaOWL, Cyclops 7F O, and Cyclops 7F-G) that might prove useful for such applications. Results show that they have significantly different dynamic ranges for detecting oil and that using them (or similar instruments) in combination is probably the best option for successfully assessing the effectiveness of oil dispersion operations. Nevertheless, the rapid dilution of dispersed oil means that measurements must be made within an hour or two of dispersion, suggesting that one feasible scenario would be monitoring ship-applied dispersants by vessels following close behind the dispersant application vessel. Alternatively, autonomous submersibles might be pre-deployed to monitor aerial dispersant application, although the logistical challenges in a real spill would be substantial. • Oil chemical dispersion is difficult to quantify in the field in a timely fashion. • Using portable field fluorometers is useful for monitoring oil chemical dispersion. • Three commercial fluorometers with different excitation/emission windows were tested. • Deployable fluorometers have significantly different dynamic ranges for detecting oil. • Using fluorometers in combination may be best for assessing dispersion's efficacy. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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10. Correction to: Dispersants as marine oil spill treating agents: a review on mesoscale tests and field trials.
- Author
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Merlin, Francois, Zhu, Zhiwen, Yang, Min, Chen, Bing, Lee, Kenneth, Boufadel, Michel C., Isaacman, Lisa, and Zhang, Baiyu
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OIL spills ,FIELD research ,DISPERSING agents ,ACQUISITION of manuscripts ,EDITORIAL boards - Published
- 2023
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11. Oil jet with dispersant: Macro-scale hydrodynamics and tip streaming.
- Author
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Zhao, Lin, Gao, Feng, Boufadel, Michel C., King, Thomas, Robinson, Brian, Lee, Kenneth, and Conmy, Robyn
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PETROLEUM ,PETROLEUM prospecting ,DISPERSING agents ,HYDRODYNAMICS ,HYDROCARBONS ,OIL spills - Abstract
Modeling the movement of oil released underwater is a challenging task due to limitations in measuring the hydrodynamics in an oil-water system. In this work, we conducted an experiment of horizontal release of oil without and with dispersant. The model VDROP-J was used and compared to the model JETLAG, a miscible plume trajectory model. Both models were found to reproduce the oil jet hydrodynamics for oil without and with dispersant. The predicted DSD from VDROP-J matched closely observation for untreated oil. For oil with dispersant, experimental results have shown evidence that tip streaming occurred. For this purpose, a new conceptual module was developed in VDROP-J to capture the tip streaming phenomenon and an excellent match was achieved with observation. This study is the first to report tip streaming occurring in underwater oil jets, which should have consequences on predicting the DSD when dispersant are used on an underwater oil release. © 2017 American Institute of Chemical Engineers AIChE J, 2017 [ABSTRACT FROM AUTHOR]
- Published
- 2017
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12. Development of an offshore response guidance tool for determining the impact of SSDI on released gas and benzene from artificial subsea oil well blowout simulations.
- Author
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Socolofsky, Scott A., Jun, Inok, Boufadel, Michel C., Liu, Ruixue, Lu, Youyu, Arey, J. Samuel, and McFarlin, Kelly M.
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BENZENE ,NATURAL gas prospecting ,OIL spills ,OIL wells ,GASES - Published
- 2022
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13. A-DROP: A predictive model for the formation of oil particle aggregates (OPAs).
- Author
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Zhao, Lin, Boufadel, Michel C., Geng, Xiaolong, Lee, Kenneth, King, Thomas, Robinson, Brian, and Fitzpatrick, Faith
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OIL removal (Sewage purification) ,COAGULATION ,PARTICLE size distribution ,OIL spills ,PREDICTION theory - Abstract
Oil–particle interactions play a major role in removal of free oil from the water column. We present a new conceptual–numerical model, A-DROP, to predict oil amount trapped in oil–particle aggregates. A new conceptual formulation of oil–particle coagulation efficiency is introduced to account for the effects of oil stabilization by particles, particle hydrophobicity, and oil–particle size ratio on OPA formation. A-DROP was able to closely reproduce the oil trapping efficiency reported in experimental studies. The model was then used to simulate the OPA formation in a typical nearshore environment. Modeling results indicate that the increase of particle concentration in the swash zone would speed up the oil–particle interaction process; but the oil amount trapped in OPAs did not correspond to the increase of particle concentration. The developed A-DROP model could become an important tool in understanding the natural removal of oil and developing oil spill countermeasures by means of oil–particle aggregation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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14. Oil droplets transport due to irregular waves: Development of large-scale spreading coefficients.
- Author
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Geng, Xiaolong, Boufadel, Michel C., Ozgokmen, Tamay, King, Thomas, Lee, Kenneth, Lu, Youyu, and Zhao, Lin
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WATER temperature ,BUOYANCY-driven flow ,OIL spills ,TURBULENT diffusion (Meteorology) ,PARTICLE tracking velocimetry - Abstract
The movement of oil droplets due to waves and buoyancy was investigated by assuming an irregular sea state following a JONSWAP spectrum and four buoyancy values. A technique known as Wheeler stretching was used to model the movement of particles under the moving water surface. In each simulation, 500 particles were released and were tracked for a real time of 4.0 h. A Monte Carlo approach was used to obtain ensemble properties. It was found that small eddy diffusivities that decrease rapidly with depth generated the largest horizontal spreading of the plume. It was also found that large eddy diffusivities that decrease slowly with depth generated the smallest horizontal spreading coefficient of the plume. The increase in buoyancy resulted in a decrease in the horizontal spreading coefficient, which suggests that two-dimensional (horizontal) models that predict the transport of surface oil could be overestimating the spreading of oil. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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15. Characterization of Turbulent Properties in the EPA Baffled Flask for Dispersion Effectiveness Testing.
- Author
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Lin Zhao, Bing Wang, Armenante, Piero M., Conmy, Robyn, and Boufadel, Michel C.
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ENVIRONMENTAL protection ,ATMOSPHERIC turbulence ,TURBULENT mixing ,PARTICLE image velocimetry ,DISPERSING agents ,DISPERSION (Chemistry) ,BOTTLES - Abstract
The baffled flask test (BFT) has been proposed by United States Environmental Protection Agency to be adopted as the official standard protocol for testing dispersant effectiveness. The mixing energy in the baffled flask is investigated in this paper. Particle image velocimetry (PIV) was used to measure the water velocity in the flask placed at an orbital shaker that was rotated at seven rotation speeds: 100, 125, 150, 160, 170, 200, and 250 rpm. Two dimensional velocity fields in large and small vertical cross sections of the flask for each rotation speed were obtained. The one-dimensional (1D) energy spectra indicates the existence of inertial subrange. The estimated average energy dissipation rates were in the range 7.65 x 10
-3 to 4 W=kg for rotation speeds of Ω = 100-250 rpm, of which it is larger than the one estimated by prior studies using single-point velocity measurement techniques for Ω = 100 and 200 rpm. Factors such as instruments used, velocity components measured, and different analysis methods could contribute to the discrepancies in the results. The Kolmogorov scale estimated in this study for all seven rotation speeds approached the size of oil droplets observed at sea, which is 50-400 µm. The average energy dissipation rate, ε and Kolmogorov microscale, η, in the flasks were correlated to the rotation speed, and it was found that ε = 9.0 x 10-5 Exp(0.043Ω) with R² = 0.97 and 77 = 1,463 Exp(-0.015Ω) with R² = 0.98. [ABSTRACT FROM AUTHOR]- Published
- 2016
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16. Simulation of scenarios of oil droplet formation from the Deepwater Horizon blowout.
- Author
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Zhao, Lin, Boufadel, Michel C., Adams, Eric, Socolofsky, Scott A., King, Thomas, Lee, Kenneth, and Nedwed, Timothy
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DEEPWATER Horizon (Drilling rig) ,PARTICLE size distribution ,MATHEMATICAL models ,MEASUREMENT ,OIL spills - Abstract
Knowledge of the droplet size distribution (DSD) from the Deepwater Horizon (DWH) blowout is an important step in predicting the fate and transport of the released oil. Due to the absence of measurements of the DSD from the DWH incident, we considered herein hypothetical scenarios of releases that explore the realistic parameter space using a thoroughly calibrated DSD model, VDROP-J, and we attempted to provide bounds on the range of droplet sizes from the DWH blowout within 200 m of the wellhead. The scenarios include conditions without and with the presence of dispersants, different dispersant treatment efficiencies, live oil and dead oil properties, and varying oil flow rate, gas flow rate, and orifice diameter. The results, especially for dispersant-treated oil, are very different from recent modeling studies in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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17. Intercomparison of oil spill prediction models for accidental blowout scenarios with and without subsea chemical dispersant injection.
- Author
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Socolofsky, Scott A., Adams, E. Eric, Boufadel, Michel C., Aman, Zachary M., Johansen, Øistein, Konkel, Wolfgang J., Lindo, David, Madsen, Mads N., North, Elizabeth W., Paris, Claire B., Rasmussen, Dorte, Reed, Mark, Rønningen, Petter, Sim, Lawrence H., Uhrenholdt, Thomas, Anderson, Karl G., Cooper, Cortis, and Nedwed, Tim J.
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OIL spills ,DISPERSING agents ,WATER depth ,PREDICTION theory ,PARTICLE size distribution ,INTERFACIAL tension - Abstract
We compare oil spill model predictions for a prototype subsea blowout with and without subsea injection of chemical dispersants in deep and shallow water, for high and low gas–oil ratio, and in weak to strong crossflows. Model results are compared for initial oil droplet size distribution, the nearfield plume, and the farfield Lagrangian particle tracking stage of hydrocarbon transport. For the conditions tested (a blowout with oil flow rate of 20,000 bbl/d, about 1/3 of the Deepwater Horizon), the models predict the volume median droplet diameter at the source to range from 0.3 to 6 mm without dispersant and 0.01 to 0.8 mm with dispersant. This reduced droplet size owing to reduced interfacial tension results in a one to two order of magnitude increase in the downstream displacement of the initial oil surfacing zone and may lead to a significant fraction of the spilled oil not reaching the sea surface. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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18. Fate of Surface Spills of Cold Lake Blend Diluted Bitumen Treated with Dispersant and Mineral Fines in a Wave Tank.
- Author
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King, Thomas L., Robinson, Brian, McIntyre, Claire, Toole, Patrick, Ryan, Scott, Saleh, Firas, Boufadel, Michel C., and Lee, Kenneth
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BITUMEN ,ENVIRONMENTAL engineering ,SALINITY ,OIL spills ,DISPERSING agents - Abstract
Cold Lake Blend (CLB) diluted bitumen (dilbit) was used to evaluate the fate and transport of preweathered (6.2% w/w) dilbit under environmental conditions both in spring (seawater temperature 8.5°C±1.3°C and salinity 27.7±1.6 practical salinity units [psu]) and in summer (seawater temperature 17.0°C±2.6°C and salinity 26.8±2.4 psu). The following oil spill treatments were considered: no treatment, dispersant alone, mineral fines (MF) alone, and dispersant+MF. The aim was to determine their influences on the fate of spilled CLB at sea. When dispersant alone was used, the highest dispersion effectiveness (DE) was noted, and DE ranged from 45% to 59% under the selected environmental conditions. With no treatment and treatment of MF alone, CLB DE was insufficient under tested conditions. Total petroleum hydrocarbon (TPH) concentration in the water column was highest for the dispersant alone, followed by that of dispersant+MF. TPH concentration for the dispersant alone increased abruptly with time. Droplet size distribution (DSD) resulting from dispersant alone had a unimodal shape, which was different than previously observed when conventional oils were treated with the dispersant. Cases of dispersant+MF were thus characterized by a broader DSD compared with dispersant only and a gradual increase in TPH concentration. This suggests that MF could be used with dispersant as a means to control the release of toxic compounds into the water column and for better engineering the response. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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19. Assessing weathered Endicott oil biodegradation in brackish water.
- Author
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Personna, Yves Robert, King, Thomas, Boufadel, Michel C., Zhang, Shuangyi, and Kustka, Adam
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MARINE ecology ,OIL spills ,BRACKISH waters ,BIODEGRADATION ,BIOMASS ,BIOAVAILABILITY ,HETEROTROPHIC bacteria - Abstract
We evaluated the biodegradability of physically (WAF) and chemically (CEWAF) dispersed oil in brackish water (salinity ∼6.5 g/L), and the influence of nutrient availability (low nutrient-LN: background water vs. high nutrient-HN: addition of 100 mg NO 3 -N/L and 10 mg PO 4 -P/L to background water) on oil biodegradation rates at 15 ± 0.5 °C for 42 days. No oil removal occurred in WAF compared with CEWAF: 24% in HN and 14% in LN within two weeks. The oil biodegradation concerned mainly alkanes as confirmed by GC/MS analyses. Higher O 2 consumption (10.30 mg L −1 day −1 ) and CO 2 production (3.89 mg C L −1 day −1 ) were measured in HN compared with LN (O 2 : 2.79 mg L −1 day −1 , CO 2 :0.18 mg C L −1 day −1 ). Estimated biomass of hydrocarbon degraders and heterotrophic bacteria was at least an order of magnitude larger in HN than in LN. Combining dispersants with nutrients could enhance oil biodegradation and help improve oil spill mitigation responses. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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20. Effects of temperature and wave conditions on chemical dispersion efficacy of heavy fuel oil in an experimental flow-through wave tank.
- Author
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Li, Zhengkai, Lee, Kenneth, King, Thomas, Boufadel, Michel C., and Venosa, Albert D.
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HEAVY oil ,DISPERSION (Chemistry) ,DISPERSING agents ,OIL spills ,ANALYSIS of covariance ,TEMPERATURE effect ,PARTICLE size distribution ,HIGH temperatures - Abstract
Abstract: The effectiveness of chemical dispersants (Corexit 9500 and SPC 1000) on heavy fuel oil (IFO180 as test oil) has been evaluated under different wave conditions in a flow-through wave tank. The dispersant effectiveness was determined by measuring oil concentrations and droplet size distributions. An analysis of covariance (ANCOVA) model indicated that wave type and temperature significantly (p <0.05) affected the dynamic dispersant effectiveness (DDE). At higher temperatures (16°C), the test IFO180 was effectively dispersed under breaking waves with a DDE of 90% and 50% for Corexit 9500 and SPC 1000, respectively. The dispersion was ineffective under breaking waves at lower temperature (10°C), and under regular wave conditions at all temperatures (10–17°C), with DDE<15%. Effective chemical dispersion was associated with formation of smaller droplets (with volumetric mean diameters or VMD⩽200μm), whereas ineffective dispersion produced large oil droplets (with VMD⩾400μm). [ABSTRACT FROM AUTHOR]
- Published
- 2010
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21. Evaluating Chemical Dispersant Efficacy in an Experimental Wave Tank: 2—Significant Factors Determining In Situ Oil Droplet Size Distribution.
- Author
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Zhengkai Li, Lee, Kenneth, King, Thomas, Boufadel, Michel C., and Venosa, Albert D.
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OIL spills ,DISPERSION (Chemistry) ,WAVE energy ,MEDIAN (Mathematics) - Abstract
Chemical dispersion is one of the most cost-effective options to remediate oil spill at open sea. Identifying significant factors that determine in situ droplet size distributions facilitates mechanistic understanding of dispersant effectiveness. In this work, in situ dispersed oil droplet size distributions were characterized during testing of chemical dispersant effectiveness of two dispersants (Corexit 9500 and SPC 1000) on two oils [Medium South American (MESA) and Alaska North Slope (ANS)] under three wave conditions (regular nonbreaking, spilling breaking, and plunging breaking waves) in an experimental wave tank. Results showed that physical dispersion generated monomodal lognormal oil droplet size distributions of larger median diameters, whereas chemical dispersion produced bi- or trimodal lognormal oil droplet size distributions of smaller median diameters over a wider range. Factorial analysis of variance (ANOVA) followed by Tukey's paired comparison statistical data analysis indicated that the volume mean diameters of dispersed oil droplets were reduced by 36 μm (from 122 to 86 μm) by plunging breaking conditions. Volume mean diameters were decreased by 92 μm (from 153 to 61 μm) and 37 μm (from 153 to 116 μm), respectively, by Corexit 9500 and SPC 1000. These results are useful in optimizing operational guidelines for dispersant use, and providing input for modeling transport, fate, and biological effects of dispersed oil. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
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22. Evaluating Chemical Dispersant Efficacy in an Experimental Wave Tank: 1, Dispersant Effectiveness as a Function of Energy Dissipation Rate.
- Author
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Zhengkai Li, Lee, Kenneth, King, Thomas, Kepkay, Paul, Boufadel, Michel C., and Venosa, Albert D.
- Subjects
EXPERIMENTAL watershed areas ,ENERGY dissipation ,HYDRODYNAMICS ,DILUTION ,ENERGY levels (Quantum mechanics) ,OIL spills ,WAVES (Physics) - Abstract
Numerous laboratory test systems have been developed for the comparison of efficacy between various chemical oil dispersant formulations. However, for the assessment of chemical dispersant effectiveness under realistic sea state, test protocols are required to produce hydrodynamic conditions close to the mixing, transport, and dilution effects found in the natural environment. To this end, we have designed and constructed an experimental wave tank system capable of generating waves of different energy levels, ranging from regular nonbreaking waves to plunging breakers. The hydrodynamics of these wave conditions were characterized using an autocorrelation function method applied to in situ velocity measurements. We report here an investigation of the effectiveness of two chemical dispersants (Corexit 9500 and SPC 1000) on two crude oils (weathered MESA and fresh ANS) under three different wave conditions in the wave tank operated in batch mode. Corexit 9500 dispersed approximately 75% of the weathered MESA and more than 90% of the fresh ANS crude, and SPC 1000 dispersed about 53 and 64%, respectively. Under control conditions (absence of chemical dispersant), only 10 to 20% of the crude oils were dispersed. Quantitative relationships were established between dispersant effectiveness and energy dissipation rate under the different simulated wave conditions. These relationships are essential for the development of accurate predictive models on dispersant effectiveness and operational guidelines for dispersant use. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
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23. Development of a dispersibility assessment kit for use on oil spill response vessels.
- Author
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Coelho, Gina M., Slaughter, Ann G., Liu, Ruixue, Boufadel, Michel C., and Broje, Victoria
- Subjects
OIL spills ,DISPERSING agents ,PETROLEUM ,EMULSIONS - Abstract
The use of dispersants can be an effective response tool for large offshore spills by applying dispersants on unemulsified slicks and treating as much oil as possible before it becomes too viscous. Assessing the dispersibility of an oil slick under actual environmental conditions is an important step in spill response decision-making. This research seeks to develop a new field kit that is quick and reliable and could be used by spill response personnel without scientific training. The resulting Dispersibility Assessment Kit (DAK) incorporates an automated mixing unit to standardize the applied energy, thereby eliminating the variability in "hand mixing" that is used in other dispersant field kits. The automated mixing energy was studied to determine the optimal mixing regime that correlates with ocean conditions and was incorporated in the DAK protocol. The DAK was validated against 14 oils and emulsions and was successfully tested by response personnel during at-sea demonstration. • This research produced a Dispersibility Assessment Kit (DAK) for spill responders. • The portable DAK supports real-time assessment of dispersants during a response. • The DAK provides a general indication of the dispersibility of an oil slick. • A sea demonstration confirmed the kit was easily operated by non-scientists. • DAK protocol instructions are provided in the Supplemental Information. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Assessment of chemical dispersant effectiveness in a wave tank under regular non-breaking and breaking wave conditions
- Author
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Li, Zhengkai, Lee, Kenneth, King, Thomas, Boufadel, Michel C., and Venosa, Albert D.
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MONITORING of dispersing agent effectiveness ,DIFFUSION in hydrology ,WAVE makers ,WAVE energy ,CHEMICAL spills ,OIL spills ,CANADA. Fisheries & Oceans Canada - Abstract
Current chemical dispersant effectiveness tests for product selection are commonly performed with bench-scale testing apparatus. However, for the assessment of oil dispersant effectiveness under real sea state conditions, test protocols are required to have hydrodynamic conditions closer to the natural environment, including transport and dilution effects. To achieve this goal, Fisheries and Oceans Canada and the US Environmental Protection Agency (EPA) designed and constructed a wave tank system to study chemical dispersant effectiveness under controlled mixing energy conditions (regular non-breaking, spilling breaking, and plunging breaking waves). Quantification of oil dispersant effectiveness was based on observed changes in dispersed oil concentrations and oil-droplet size distribution. The study results quantitatively demonstrated that total dispersed oil concentration and breakup kinetics of oil droplets in the water column were strongly dependent on the presence of chemical dispersants and the influence of breaking waves. These data on the effectiveness of dispersants as a function of sea state will have significant implications in the drafting of future operational guidelines for dispersant use at sea. [Copyright &y& Elsevier]
- Published
- 2008
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25. Effects of chemical dispersants and mineral fines on crude oil dispersion in a wave tank under breaking waves
- Author
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Li, Zhengkai, Kepkay, Paul, Lee, Kenneth, King, Thomas, Boufadel, Michel C., and Venosa, Albert D.
- Subjects
OIL pollution of water ,SUSPENDED sediments ,DISPERSION (Chemistry) ,ENVIRONMENTAL disasters ,OIL spills ,SPECTRUM analysis ,GAS chromatography ,TRANSMISSOMETERS ,PARTICLE size determination - Abstract
The interaction of chemical dispersants and suspended sediments with crude oil influences the fate and transport of oil spills in coastal waters. A wave tank study was conducted to investigate the effects of chemical dispersants and mineral fines on the dispersion of oil and the formation of oil–mineral-aggregates (OMAs) in natural seawater. Results of ultraviolet spectrofluorometry and gas chromatography flame ionized detection analysis indicated that dispersants and mineral fines, alone and in combination, enhanced the dispersion of oil into the water column. Measurements taken with a laser in situ scattering and transmissometer (LISST-100X) showed that the presence of mineral fines increased the total concentration of the suspended particles from 4 to 10μll
−1 , whereas the presence of dispersants decreased the particle size (mass mean diameter) of OMAs from 50 to 10μm. Observation with an epifluorescence microscope indicated that the presence of dispersants, mineral fines, or both in combination significantly increased the number of particles dispersed into the water. [Copyright &y& Elsevier]- Published
- 2007
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- View/download PDF
26. Tracer Studies in Laboratory Beach Simulating Tidal Influences.
- Author
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Boufadel, Michel C., Suidan, Makram T., and Venosa, Albert D.
- Subjects
- *
OIL spills , *BIOREMEDIATION , *BEACHES , *TIDES , *MICROORGANISMS , *BACTERIA , *PLUMES (Fluid dynamics) , *GROUNDWATER tracers - Abstract
Bioremediation of oil spills on tidally influenced beaches commonly involves the addition of a nutrient solution to the contaminated region of the beach at low tide to stimulate the growth of indigenous oil-degrading bacteria. Maximizing the residence time of nutrients in the beach and subsequently their contact time with microorganisms is a main goal for successful bioremediation. Therefore, understanding the effects of the tide on water flow and solute transport in a beach is an essential task for designing a nutrient application strategy. We investigated these effects by conducting a tracer study in a laboratory beach simulating nutrient application on natural beaches. The study consisted of applying, at low tide, a conservative tracer solution onto the beach surface near the high-tide line and monitoring its movement in the beach subsurface. The tidal motion caused the applied plume to move downward and seaward. The downward movement occurred during rising tides, while the seaward movement occurred mainly during falling tides. The results indicate that nutrients should be applied at the high-tide line during low tides. Guidelines for scaling up the results to natural beaches are provided along with an example. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
27. Evaluation of Mixing Energy in Laboratory Flasks Used for Dispersant Effectiveness Testing.
- Author
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Kaku, Vikram J., Boufadel, Michel C., and Venosa, Albert D.
- Subjects
- *
OIL spills , *POLLUTION , *WASTE spills , *BOTTLES , *ANEMOMETER , *METEOROLOGICAL instruments , *WIND speed measurement , *ENVIRONMENTAL protection , *LABORATORIES - Abstract
The evaluation of dispersant effectiveness used for oil spills is commonly done using tests conducted in laboratory flasks. The success of a test relies on replication of the conditions at sea. We used a hot wire anemometer to characterize the turbulence characteristics in the swirling flask (SF) and the baffled flask (BF), the latter is being considered by the Environmental Protection Agency to replace the prior. We used the measurements to compute the velocity gradient, G and the energy dissipation rate per unit mass, [variant_greek_epsilon]. The study shows that the mixing in the BF is more uniformly distributed than that in the SF. Flask average energy dissipation rates in the SF were about 2 orders of magnitude smaller than those in the BF. The sizes of the microscales in the BF were found to be much smaller than that in the SF. Also, in the BF, the sizes of the microscales approached the size of oil droplets observed at sea (50–400 μm), which means that the turbulence in the BF closely resembles the turbulence occurring at sea during breaking waves. Hence, the BF is preferable for dispersant testing in the laboratory. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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- View/download PDF
28. Decision support tools for oil spill response (OSR-DSTs): Approaches, challenges, and future research perspectives.
- Author
-
Yang, Zhaoyang, Chen, Zhi, Lee, Kenneth, Owens, Edward, Boufadel, Michel C., An, Chunjiang, and Taylor, Elliott
- Subjects
OIL spills ,COLD regions - Abstract
Marine oil spills pose a significant threat to ocean and coastal ecosystems. In addition to costs incurred by response activities, an economic burden could be experienced by stakeholders dependent on coastal resources. Decision support tools for oil spill response (OSR-DSTs) have been playing an important role during oil spill response operations. This paper aims to provide an insight into the status of research on OSR-DSTs and identify future directions. Specifically, a systematic review is conducted including an examination of the advantages and limitations of currently applied and emerging decision support techniques for oil spill response. In response to elevated environmental concerns for protecting the polar ecosystem, the review includes a discussion on the use of OSR-DSTs in cold regions. Based on the analysis of information acquired, recommendations for future work on the development of OSR-DSTs to support the selection and implementation of spill response options are presented. [Display omitted] • A systematic review of current decision support approaches for oil spill response. • Decision support to oil spills in typical conditions and cold region is researched. • The decision support tools for oil spill response are categorized for the first time. • Novel integration of decision tools in an incident management system is discussed. • Future direction of the decision tools for oil spill response is deliberated. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
29. On the transport and landfall of marine oil spills, laboratory and field observations.
- Author
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Novelli, Guillaume, Guigand, Cédric M., Boufadel, Michel C., and Özgökmen, Tamay M.
- Subjects
OIL spills ,PETROLEUM ,SURFACES (Technology) - Abstract
The dynamics of crude oil and different surface ocean drifters were compared to study the physical processes that govern the transport and landfall of marine oil spills. In a wave-tank experiment, drifters with drogue did not follow oil slicks. However, patches of undrogued drifters and thin bamboo plates did spread at the same rate and in the same direction as the crude oil slicks. Then, the trajectories of the Deepwater Horizon oil spill and 1300 drifters released near the spill source were investigated. Undrogued drifters were transported twice as fast as drogued drifters across the isobaths. 25% of the undrogued drifters landed, versus about 5% of the drogued ones, for the most part, on the same coastline locations where oil was found after Deepwater Horizon. Results highlight the importance of near surface gradients in controlling the cross-shelf transport and landing of surface material on the Gulf of Mexico's northern shores. • Undrogued drifters and crude oil slicks advect and disperse similarly in waves. • Undrogued drifters make landfall 5 times more than near-surface drogued drifters. • Near-surface vertical shear sets the cross-shelf transport of surface material. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. Computation of the Mixing Energy in Rivers for Oil Dispersion.
- Author
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Boufadel, Michel C., Fitzpatrick, Faith, Cui, Fangda, and Lee, Kenneth
- Subjects
- *
PETROLEUM , *SUSPENDED sediments , *OIL spills , *WATER depth , *WATER , *RIVER channels - Abstract
With the increase in transport of oil by rail, the probability of oil spills in rivers has increased. Traditionally, focus has been placed on oil slicks moving on the water surface. However, the density of bitumen oil carried by rail within and from Canada to the United States can exceed that of freshwater, causing this oil to get submerged in the water column. This also has the potential of forming oil particle aggregates (OPAs) upon interaction with suspended sediments. The energy-dissipation rate is a key parameter for predicting the formation of oil droplets, and for this purpose, expressions are developed to estimate the energy-dissipation rate at various depths in the river using easily measured quantities such as water depth, streambed slope, and streambed roughness. The formulation showed that for a stream 30 m wide with a natural slope of 1/1,000 and roughness height of 1.0 cm, the average and maximum energy-dissipation rates are 0.01 and 0.22 W/kg , respectively. The average value is comparable to spilling breakers of height around 0.3 m, and the maximum value is comparable to those obtained from plunging breakers of 0.30-m-high waves. The large average value suggests that breakup of droplets in streams is higher than in the open sea under regular waves. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
31. VDROP: A comprehensive model for droplet formation of oils and gases in liquids - Incorporation of the interfacial tension and droplet viscosity.
- Author
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Lin Zhao, Torlapati, Jagadish, Boufadel, Michel C., King, Thomas, Robinson, Brian, and Lee, Kenneth
- Subjects
- *
OIL-water interfaces , *DROPLETS , *DISSOLUTION (Chemistry) , *BIODEGRADATION , *OIL spills , *VISCOSITY , *INTERFACIAL tension - Abstract
Knowledge of the droplet size distribution (DSD) of spilled oil is essential for accurate prediction of oil dissolution and biodegradation. To predict DSD in turbulent flow, understanding the two resisting forces to droplet breakup are important: oil-water interfacial tension (IFT) and oil viscosity. Most existing predictive models consider only resisting force to droplet breakup due to IFT. However, in situations (e.g., high oil viscosity or low IFT) when oil viscosity becomes important, neglecting the resistance to breakup due to oil viscosity overestimates the extent of droplet breakage, and produces erroneously droplets of smaller size than reality. For these reason, we introduced a comprehensive conceptual-numerical model, VDROP, capable of simulating the transient droplet size distribution (DSD) in turbulent regimes while accounting for both oil viscosity and the oil-water IFT in resisting breakup. The residence time of high viscosity (and/or small IFT) oils in systems is more important than that of the low viscosity (and/or large IFT) oils. An expedient formulation was introduced to account for the residence time of high viscosity oils. Results showed that the model was able to reproduce the transient droplet size distribution of both low and high viscosity oils. VDROP was then used to provide the DSD of oils in breaking waves, and various IFT (due to usage of surfactant) and oil viscosities were considered. The results show that the transient DSD of high viscosity oils was bimodal and converged to unimodal when approaching steady state, which occurred within 2 h for considered case. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. Fractal scaling behavior of a sea ice draft field in the Chukchi Sea.
- Author
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Frazier, Kelsey, Gerges, Firas, and Boufadel, Michel C.
- Subjects
- *
SEA ice , *ICE fields , *MULTIFRACTALS , *OIL spills , *SONAR - Abstract
In the event that an Arctic oil spill occurs, oil spill modelers need to understand how oil moves along the subsurface of sea ice to predict how a slick will migrate. Currently, modeling the subsurface topography of sea ice has been hampered by a lack of understanding of this complex surface. Using sonar data from the Chukchi Sea, an investigation into whether this subsurface topography exhibited fractal scaling behavior was initiated. It was established that young sea ice exhibits multifractal scaling geometry parameters α , c 1, and H as 1.2, 0.03, and 0.12, respectively. Fractal scaling behavior was not found for other types of sea ice. Having established such an analysis is useful, future efforts to expand the work are suggested. • New sea ice displays multifractal scaling geometry. • Older sea ice does not display multifractal scaling geometry. • Application of the Universal Multifractal model to sea ice in the Chukchi Sea [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. A generic approach to construct pseudo components for oil weathering models.
- Author
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Geng, Xiaolong, Barker, Christopher H., MacFadyen, Amy, Boufadel, Michel C., Thrift-Viveros, Dalina L., Jones, Robert K., O'Connor, Caitlin, and Lee, Kenneth
- Subjects
- *
PETROLEUM products , *PETROLEUM , *BOILING-points , *OIL spills , *WEATHERING - Abstract
Oil weathering models are essential for predicting the behavior of spilled oil in the environment. Most models use a "Pseudo Component" (PC) approach to represent the wide range of compounds found in petroleum products. Within the approach, rather than modeling each individual compound in an oil, a manageable number of PCs are developed that represent whole classes of compounds. However, previous studies focused mainly on traditional crude oils and did not develop a generic approach to create an optimal set of PCs for a variety of oils. In developing the updates to the NOAA oil weathering model, we propose herein a generic approach to construct PCs using oil distillation data to capture the complexity of oil evaporative weathering. We validated our approach with 899 oils from the Automated Data Inquiry for Oil Spills (ADIOS) oil library and found that an optimal set of sixteen PCs should be used. These PCs include two with low boiling point (below 144 °C), one with a high boiling point (above 400 °C), and thirteen constructed within a middle range of boiling points with a temperature resolution of 20 °C. Our simulation tests suggested that this set of sixteen PCs adequately characterizes oil evaporation processes for a wide variety of oils. [Display omitted] • A pseudo-component approach is developed for modeling oil evaporative weathering. • 16 pseudo-components constructed to model oil evaporation are tested with 899 oils. • Empirical formulas are derived to estimate pseudo-components' density and viscosity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Underwater oil jet: Hydrodynamics and droplet size distribution.
- Author
-
Zhao, Lin, Shaffer, Franklin, Robinson, Brian, King, Thomas, D’Ambrose, Christopher, Pan, Zhong, Gao, Feng, Miller, Richard S., Conmy, Robyn N., and Boufadel, Michel C.
- Subjects
- *
OIL spills , *HYDRODYNAMICS , *PARTICLE size distribution , *BUOYANCY , *MOMENTUM (Mechanics) - Abstract
We conducted a large scale experiment of underwater oil release of 6.3 L/s through a 25.4 mm (one inch) horizontal pipe. Detailed measurements of plume trajectory, velocity, oil droplet size distribution, and oil holdup were obtained. The obtained experimental data were used for the validation of the models JETLAG and VDROP-J. Key findings include: (1) formation of two plumes, one due to momentum and subsequently plume buoyancy, and another due mostly to the buoyancy of individual oil droplets that separate upward from the first plume; (2) modeling results indicated that the traditional miscible plume models matched the momentum and buoyancy plume, but were not able to simulate the upward motion plume induced by individual oil droplets; (3) high resolution images in the jet primary breakup region showed the formation of ligaments and drops in a process known as “primary breakup”. These threads re-entered the plume to re-break in a process known as “secondary breakup”; (4) the plume velocity was highly heterogeneous with regions of high velocity surrounded by stagnant regions for various durations. The results from this study revealed that the primary breakup is a key factor for quantifying the droplet size distribution which plays a crucial role in determining the ultimate fate and transport of the released oil in the marine environment. The observed spatial heterogeneity in the oil plume implies that the effectiveness of applied dispersants may vary greatly when applying directly in the discharged oil flow. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
35. Estimation of overall droplet size distribution from a local droplet size distribution for a jet in crossflow: Experiment and multiphase large eddy simulations.
- Author
-
Daskiran, Cosan, Liu, Ruixue, Lee, Kenneth, Katz, Joseph, and Boufadel, Michel C.
- Subjects
- *
LARGE eddy simulation models , *CROSS-flow (Aerodynamics) , *RELATIVE velocity , *SPEED , *REYNOLDS number , *OIL spills , *ENERGY dissipation - Abstract
• Experiment and multiphase large eddy simulations (LES) of oil jet in crossflow. • LES was coupled with the population balance model to compute local droplet size. • Maximum energy dissipation rate after 16 pipe diameters distance from the orifice was not sufficient to break the droplets injected at the orifice. • Plume DSD changed slightly after 15 pipe diameters distance from the orifice. • Overall plume DSD can be estimated from the measurement at a single point in the plume. A local droplet size distribution (DSD) from a jet in crossflow can overestimate or underestimate the overall DSD in the plume based on the measurement location. The overall DSD is crucial to evaluate the fate of oil droplets in the water column for a proper countermeasure following an oil spill. We present experimental results of a vertical oil jet in crossflow with a jet velocity of 2.4 m/s and a crossflow speed of 0.31 m/s, resulting jet-to-crossflow velocity ratio of 7.7 and a jet Reynolds number of 13,400. We measured the droplet size near the top and bottom boundaries of the plume while filming the whole plume. We conducted multiphase large eddy simulations coupled with a population balance model considering the relative velocity among the phases in the momentum and volume fraction equations. The computed plume boundaries and the DSD from the simulations agreed well with the measurements. The Sauter mean diameter and DSD considering all droplets across the plume cross-sections were found to be changing slightly beyond s/D ≈ 15. By considering different plume cross-sections for s/D> 15 and different droplet breakage rates, the overall DSD in a plume cross-section can be obtained locally near thevertical centerline of the plume cross-section (y/D = 0) at (58.8 ± 6.2)% of the plume cross-section height from the bottom boundary of the plume. The trajectory of the local DSD representing the overall DSD was found slightly below the plume trajectory. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
36. Proof of concept study for in-situ burn application using conventional containment booms – Design of Burning Tongue.
- Author
-
Zhao, Lin, Daskiran, Cosan, Mitchell, Douglas A., Panetta, Paul D., Boufadel, Michel C., and Nedwed, Tim J.
- Subjects
- *
PROOF of concept , *TONGUE , *OIL spills , *HYDRODYNAMICS - Abstract
In situ burning (ISB) hasn't been widely used for offshore oil spill response for various reasons. We present a feasibility study for a new ISB method – the Burning Tongue (BT) concept. We conducted scaled experiments in the Ohmsett wave tank to demonstrate its feasibility. We produced a 35-m long "tongue" of burnable oil (average oil thickness 4.2 mm – above the thickness needed for ISB) by towing a conventional boom (with a 12″ (0.3 m) deep skirt) partially filled with crude oil and then released the oil through a 6″ (0.15 m) wide opening at the apex. We found that the boom movement produced a convergence zone just downstream that kept released oil thick and also pulled oil that entrained under the boom skirt into the thick "tongue" of oil. CFD modeling was performed to explain the flow hydrodynamics and the formation of the convergence zone, which indicates the phenomenon is universal. We used small harbor boom only partially filled with oil for this study and believe that a full-scale marine boom filled with oil would achieve an even thicker "burning tongue." The BT concept could make ISB more widely used for oil spill response in offshore areas. [Display omitted] • A new ISB concept for offshore application – the Burning Tongue is introduced. • Scaled experiments in a large wave tank successfully demonstrated its feasibility. • The produced 35-m long, 4.2 mm thick oil tongue was well above burning requirements. • A convergence zone was formed downstream of the boom to keep the oil tongue thick. • CFD modeling explained the flow hydrodynamics. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
37. Recent advances in chemical and biological degradation of spilled oil: A review of dispersants application in the marine environment.
- Author
-
Zhu, Zhiwen, Merlin, Francois, Yang, Min, Lee, Kenneth, Chen, Bing, Liu, Bo, Cao, Yiqi, Song, Xing, Ye, Xudong, Li, Qingqi K., Greer, Charles W., Boufadel, Michel C., Isaacman, Lisa, and Zhang, Baiyu
- Subjects
- *
BIODEGRADATION , *CHEMICAL decomposition , *DISPERSING agents , *SEA birds , *OIL spills , *PETROLEUM - Abstract
Growing concerns over the risk of accidental releases of oil into the marine environment have emphasized our need to improve both oil spill preparedness and response strategies. Among the available spill response options, dispersants offer the advantages of breaking oil slicks into small oil droplets and promoting their dilution, dissolution, and biodegradation within the water column. Thus dispersants can reduce the probability of oil slicks at sea from reaching coastal regions and reduce their direct impact on mammals, sea birds and shoreline ecosystems. To facilitate marine oil spill response operations, especially addressing spill incidents in remote/Arctic offshore regions, an in-depth understanding of the transportation, fate and effects of naturally/chemically dispersed oil is of great importance. This review provides a synthesis of recent research results studies related to the application of dispersants at the surface and in the deep sea, the fate and transportation of naturally and chemically dispersed oil, and dispersant application in the Arctic and ice-covered waters. Future perspectives have been provided to identify the research gaps and help industries and spill response organizations develop science-based guidelines and protocols for the application of dispersants application [Display omitted] • Factors controlling the biodegradation of chemically dispersed oil were discussed. • Photo-oxidation of chemically dispersed oil and the transformation were assessed. • Biodegradation and photo-oxidation of chemical dispersants were reviewed. • Dispersant applications in the Arctic and cold waters were summarized. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
38. Oil biodegradation in permeable marine sediments: Effects of benthic pore-water advection and solute exchange.
- Author
-
Geng, Xiaolong, Barker, Christopher H., MacFadyen, Amy, Boufadel, Michel C., Lee, Kenneth, Thrift-Viveros, Dalina L., Jones, Robert, and O'Connor, Caitlin
- Subjects
- *
MARINE sediments , *BIODEGRADATION , *PETROLEUM , *ADVECTION , *FLOW simulations , *OIL spills , *SEDIMENT transport - Abstract
Oil spills have been recognized as among the worst kinds of environmental disasters, causing severe coastal ecological and economic damages. Although benthic flow and solute fluxes are known to have strong impacts on fate and transport of oil deposited within marine sediments, their endogenous mechanisms still remain to be uncovered. In this paper, simulations of flow and solute transport processes along with hydrocarbon biodegradation were conducted in a cylindrical benthic chamber system to investigate influences of benthic hydrodynamics on oil biodegradation in permeable marine sediments. Results show that ripple-flow interactions create subsurface recirculation cells whereby seawater infiltrates into the benthic sediments at ripple troughs while groundwater discharges near the crests. It results in a spatially varied oil biodegradation rate in marine sediments. Significant oil biodegradation occurs near sediment ripple troughs due to direct oxygen recharge, while biodegradation of oil deposited uphill becomes slow due to limited oxygen replenishment. Oil biodegradation decreases subsurface oxygen content, and consequently impedes discharge of oxygen from benthic sediments. Our results reveal a dynamic interaction between oil biodegradation and benthic flow and solute transport processes, which has strong implications for predicting oil persistence and biodegradation within marine sediments and its associated impacts on benthic biogeochemical processes. [Display omitted] • Ripple-flow interactions cause benthic spatially varied oil biodegradation rate. • Benthic oil biodegradation primarily depends on local topographic and flow patterns. • Oil biodegradation primarily occurs in ripple troughs due to direct oxygen recharge. • Biodegradation of benthic oil deposited uphill is slow due to anaerobic conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
39. Crude oil biodegradation in upper and supratidal seashores.
- Author
-
Abou Khalil, Charbel, Fortin, Nathalie, Prince, Roger C., Greer, Charles W., Lee, Kenneth, and Boufadel, Michel C.
- Subjects
- *
BIODEGRADATION , *SEASHORE , *INTERTIDAL zonation , *SEAWATER salinity , *AEROBIC bacteria , *PETROLEUM , *OIL spills - Abstract
The salinity of the upper parts of seashores can become higher than seawater due to evaporation between tidal inundations. Such hypersaline ecosystems, where the salinity can reach up to eight-fold higher than that of seawater (30–35 g/L), can be contaminated by oil spills. Here we investigate whether such an increase has inhibitory effects on oil biodegradation. Seawater was evaporated to a concentrated brine and added to fresh seawater to generate high salinity microcosms. Artificially weathered Hibernia crude oil was added, and biodegradation was followed for 76 days. First-order rate constants (k) for the biodegradation of GC-detectable hydrocarbons showed that the hydrocarbonoclastic activity was substantially inhibited at high salt – k decreased by ~75% at 90 g/L salts and ~90% at 160 g/L salts. This inhibition was greatest for the alkanes, although it extended to all classes of compounds measured, with the smallest effect on four-ring aromatics (e.g., chrysenes). Genera of well-known aerobic hydrocarbonoclastic bacteria were only identified at 30 g/L salts in the presence of oil, and only a few halophilic Archaea showed a slight enrichment at higher salt concentrations. These results indicate that biodegradation of spilled oil will likely be slowed in supratidal ecosystems and suggest that occasional irrigation of oiled supratidal zones could be a useful supporting strategy to remediation processes. [Display omitted] • Supratidal and intertidal zones of seashores are transiently hypersaline. • Hydrocarbon evaporation rate is higher in hypersaline seashores than in seawater. • Biodegradation of oil is noticeably slowed when salinity increases in seawater. • Biodegradation of alkanes slows more than PAHs at high salinities. • Inundation of oiled supratidal seashores would enhance the biodegradation of oil. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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