Robert J. Fiocco

WEATHERING AND CHEMICAL DISPERSION OF OIL AT SEA

ABSTRACT Small-scale laboratory methods were used to simulate the weathering processes that occur when crude oil is spilled at sea. Changes caused by evaporation and water-in-oil (w/o) emulsificati...

Key Parameters Affecting the Dispersion of Viscous Oil

ABSTRACT Oil viscosity has been perceived as a major factor affecting the dispersibility of oil. Very high viscosity oils—20,000 centistokes (cs) or more—can readily be observed as resisting the breakup of the oil into dispersed droplets. However, there are instances where a relatively viscous oil will disperse much more readily than another oil of similar viscosity. An extensive study has been conducted at ExxonMobil Research facilities in New Jersey to define the molecular makeup of 14 viscous heavy fuel oil products and determine the property of the viscous oils, besides viscosity, that influences dispersibility. Dispersibility was measured by a standard laboratory dispersant test using a COREXIT dispersant selected from the U.S. Environmental Protection Agency (EPA) National Contingency Plan (NCP) Product Schedule. Initially, IATROSCAN (TLC) and gas chromatography data failed to show any correlation between chemical properties, such as sulfur, aromatics, paraffins, resins, vanadium, nickel content, et...

MODIFICATION OF THE DISPERSANT COREXIT®9500 FOR USE IN FRESHWATER

ABSTRACT Recent inland spills in Latin America have generated interest in dispersant use for freshwater oil spills. However, oil spill dispersants primarily are formulated for use in marine waters....

Development of Corexit 9580—A Chemical Beach Cleaner

ABSTRACT Chemical beach cleaners can facilitate cleanups of oiled shorelines by improving the efficiency of washing with water. The improvement is a result of reduced adhesion of the oil coating, which makes it easier to remove from shoreline surfaces, thereby reducing washing time and lowering the temperature of the wash water needed to clean a given area. The criteria established for use of chemical beach cleaners in the Exxon Valdez spill cleanup included demonstrating enhanced cleaning with low levels of toxicity to marine biota and with minimal oil dispersion. Since no commercially available products satisfactorily met these criteria for use in Alaska, a new product, Corexit 9580, was specifically developed in response to this need. This paper describes the successful development of this chemical, including both laboratory testing and field testing in Prince William Sound.

DEMULSIFYING DISPERSANT FOR AN EXTENDED WINDOW OF USE

ABSTRACT Recent data with a modern demulsifying oil spill dispersant (Corexit 9500) challenge old viscosity limits for the window of opportunity for dispersant use on viscous oils and emulsions. Th...

A NEW LABORATORY METHOD FOR EVALUATING OIL SPILL DISPERSANTS

ABSTRACT A new dispersant effectiveness test, named EXDET, was developed to address certain concerns associated with currently available laboratory dispersant effectiveness test procedures. This ne...

The Impact of Oil Dispersant Solvent on Performance

Modern oil spill dispersant formulations are concentrated blends of surface active agents (surfactants) in a solvent carrier system. The surfactants are effective for lowering the interfacial tension of the oil slick and promoting and stabilizing oil-in-water dispersions. The solvent system has 2 key functions: (1) reduce viscosity of the surfactant blend to allow efficient dispersant application, and (2) promote mixing and diffusion of the surfactant blend into the oil film. A more detailed description than previously given in the literature is proposed to explain the mechanism of chemical dispersion and illustrate how the surfactant is delivered by the solvent to the oil-water interface. Laboratory data are presented which demonstrate the variability in dispersing effectiveness due to different solvent composition, particularly for viscous and emulsified test oils with viscosities up to 20,500 mPa{center_dot}s. Other advantages of improved solvent components can include reduced evaporative losses during spraying, lower marine toxicity and reduced protective equipment requirements. Through this improved understanding of the role of the solvent, dispersants which are more effective over a wider range of oil types are being developed.

CRUDE OIL VANADIUM AND NICKEL CONTENT CAN PREDICT EMULSIFICATION TENDENCY

ABSTRACT Most crude oils in contact with water form water-in-oil emulsions. The stability of these emulsions will vary. When spilled crude oil emulsifies, it becomes viscous and expands in volume, ...

COREXIT 9580 shoreline cleaner: Development, application, and status

This paper will describe research on chemical beach cleaners for treatment of oiled shorelines that was initiated in support of the cleaning activities in Prince William Sound (PWS) following the Valdez oil spill in March 1989. The concept for using beach cleaners for shoreline cleanup is to apply a pre-soak to the weathered crude oil on shore and then flush with sea water to wash the oil into a boomed area for subsequent recovery. Criteria imposed on the use of chemical beach cleaners for the cleanup of the Valdez spill were: (1) effective rock cleaning agents should have very little or no toxicity to marine and terrestrial life, (2) there should be no dispersion of the oil washed from the shoreline into the water column; oil was to be recovered by techniques such as skimming or sorbents, and (3) the agents should be on the EPA National Contingency Plan (NCP) list. A laboratory-scale rock washing test was developed to measure cleaner effectiveness and dispersion. A large number of commercially available formulated products were evaluated, as well as development formulations. The commercial products included all of the available NCP-listed products which could function as cleaners. None of the commercial products completelymorexa0» satisfied all the requirements established by the agencies for beach cleaning. However, a new formula, called COREXIT 9580, consisting of two surfactants and a solvent was developed. It exhibited low fish toxicity, low dispersancy and effective rock cleaning capability. The paper reviews the laboratory and field testing to explore the potential use of the COREXIT 9580 to save and restore oiled vegetation.«xa0less

IMPROVED LABORATORY DEMULSIFICATION TESTS FOR OIL SPILL RESPONSE

ABSTRACT A critical need currently exists for standard laboratory procedures for evaluating demulsifiers over the range of applications encountered in oil spill response. The procedures should be f...