MULTIVARIATE ANALYSIS OF PETROLEUM HYDROCARBON WEATHERING IN THE SUBARCTIC MARINE ENVIRONMENT1

1983 ◽  
Vol 1983 (1) ◽  
pp. 423-434 ◽  
Author(s):  
James R. Payne ◽  
Bruce E. Kirstein ◽  
G. Daniel McNabb ◽  
James L. Lambach ◽  
Celso de Oliveira ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Physical Properties ◽  
Crude Oil ◽  
Water Column ◽  
Oil Spills ◽  
Model Development ◽  
Material Balance ◽  
Oil Composition ◽  
Outer Continental Shelf ◽  
Weathering Processes

ABSTRACT When crude oil or petroleum products are released to the marine environment, immediate alterations in chemical and physical properties occur as a result of a variety of weathering processes. A three-year oil weathering study of Prudhoe Bay crude oil has been completed under ambient subarctic conditions at the National Oceanic and Atmospheric Administration's lower Cook Inlet field laboratory in Kasitsna Bay, Alaska. Quantitative data from outdoor wave-tank and flow-through aquaria systems were collected on seasonal and time-series measurements of compositional changes in the oil and water column due to evaporation, dissolution, and water-in-oil emulsification, as well as alterations in rheological properties of the slick. These data are used for mathematical model development and verification of computer-predicted oil weathering behavior from a variety of spill scenarios. The oil-weathering mathematical models developed in this program are based on measured physical properties data, and they generate material balances for both specific compounds and pseudo-compounds (distillation cuts) in crude oil. These models are applicable to open-ocean oil spills, spills in estuaries and lagoons where the water column is finite, and spills on land. The oil weathering processes included in the mathematical model are evaporation, dispersion of oil into the water column, dissolution, water-in-oil emulsification (mousse formation), and oil slick spreading. In most cases, very good agreement is obtained between predicted and observed weathering behavior. The material balance and weathered-oil composition predictions generated as a function of time have been very useful in providing information for contingency planning, estimating potential damage assessments and preparing environmental impact reports for outer continental shelf drilling activities.

Modelling the behaviour of oil spills in natural waters

1993 ◽  
Vol 20 (2) ◽  
pp. 210-219 ◽  
Author(s):  
G. K. Luk ◽  
H. F. Kuan
Keyword(s):  
Mathematical Model ◽  
Natural Waters ◽  
Oil Spills ◽  
State Of The Art ◽  
Oil Composition ◽  
Weathering Processes ◽  
Transport And Mixing ◽  
Spilled Oil ◽  
Initial Results ◽  
Petroleum Oil

This paper is a state-of-the-art review of the formulations for the different processes responsible for the transport and mixing of petroleum oil spilled in natural waters. Processes accounting for the transfer and loss of the surface oil, such as initial spreading, evaporation, dissolution, emulsification, dispersion, photo-oxidation, and sedimentation, are included. Based on the findings, a dynamic mathematical model describing the fate of spilled oil was developed. To reflect field observations, the surface oil composition in the model is allowed to vary with time as a result of weathering. Initial results for model testing are presented. Key words: oil spill, mathematical model, fate model, weathering processes.

How much oil is actually removed by evaporation, photo-oxidation and microbial weathering?

2017 ◽  
Vol 2017 (1) ◽  
pp. 2017292
Author(s):  
Puspa L. Adhikari ◽  
Edward B. Overton ◽  
Martin S. Miles ◽  
Roberto L. Wong
Keyword(s):  
Crude Oil ◽  
Water Column ◽  
Significant Proportion ◽  
Complex Mixture ◽  
Natural Seawater ◽  
Weathering Processes ◽  
Left Behind ◽  
Direct Estimation ◽  
Actual Amount ◽  
Spilled Oil

Crude oil is a complex mixture of thousands of organic compounds including alkanes, aromatics, asphaltenes, resins and waxes. A number of physical, chemical and biological weathering processes, as well as, vertical sinking followed by burial in sediments act on oil once it is released into the marine waters. The weathering processes cause oil's initial concentration/composition to change into oil residues, and allow natural mechanisms for oxidation and conversion of reduced organic carbons in oil back to CO2 and biomass. Once the lighter compounds are gone due to weathering, and some new oxidative compounds are formed, the heavier constituents left behind as residues ultimately sink to the bottom and/or strand at the coasts. The oil and oil residues can persist much longer in soil and sediments (20–40 years) than in the water column (<6 months), and can have long-term environmental impacts. Thus, it is important to know the amount and fates of the residues produced and transported to the seafloor and/or to the coastal marshes after early oil weathering in marine water column. The understanding of likely fates and behavior of oil allows us to choose and optimize a most appropriate response option. Recent studies have considered hopane as degradation resistant, used hopane normalization to determine the loss of select oil constituents via weathering, and have concluded that a significant proportion of spilled oil quickly is removed. Such analysis, however, are based on percentage removal of GC-amenable alkanes and PAHs, and may not represent the actual amount of loss of spilled oil via weathering processes as a large fractions of the crude oils (higher alkanes, PAHs, oxidative products, asphaltenes, resins and wax) are not GC-amenable which are not accounted in GC-based analysis. In the present study, we conducted a series of laboratory weathering experiments for direct estimation of the actual amount of loss of crude oil via evaporation and biodegradation. A known amount (mass) of BP surrogate oil was mixed into the natural seawater and allowed for weathering for 30 days, simulating natural physical conditions and periodically flushing the water to prevent accumulation of biomass. At the end of the experiment, oil residues were carefully collected, solvent extracted followed by evaporation of solvent and weighing the residues left behind. The comparison of pre-post mass, and mass balance including flushed water, provides direct estimation of loss of oil via weathering. This is a work-in-progress and results will be presented during the conference.

FATE OF CRUDE OIL SPILLED IN A SIMULATED ARCTIC ENVIRONMENT

1977 ◽  
Vol 1977 (1) ◽  
pp. 461-463 ◽  
Author(s):  
C. MacGregor ◽  
A. Y. McLean
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
The Arctic ◽  
Oil Composition ◽  
Liquid Chromatograph ◽  
Weathering Processes ◽  
Mixing Energy ◽  
Ultimate Fate ◽  
Physical And Chemical ◽  
Crude Oil Spill

ABSTRACT A simulated Arctic crude oil spill was investigated by monitoring physical and chemical changes in a laboratory spill of Guanipa (Venezuelan) crude. The spill consisted of one gallon of crude on 100 gallons of synthetic seawater contained in a fiberglass tank fitted with a wave generator and a controlled radiation system, all located in an environmental chamber held at 2°C. Changes in oil composition were monitored using a gas liquid Chromatograph. Evaporation removed the largest quantity of material from the spill, the rate varying directly with the exposure time to solar radiation. Solution or sinking removed only minimal quantities of oil although the influence of these factors increased with time. The most notable physical change was the rapid formation of stable emulsions. These emulsions formed discrete lumps commonly referred to as “tarballs.” The formation of tarballs occurred within a few days after the spill and they remained stable over the four-month duration of the experiment. Their formation drastically reduced weathering effects by removing the bulk of the oil from contact with the air/seawater interface. It was concluded that a crude oil spill in the Arctic could contribute significantly to tarball pollution of northern oceans. Tarball formation is not limited, therefore, to warm waters and occurs independently of weathering processes. It would appear that tarball formation depends more on the chemical composition of the oil and the rate of formation depends upon the available wave mixing energy. The ultimate fate of oil spilled in Arctic regions could be in the form of persistent tarballs.

Modeling of Glass Melting Process in Plasma-Fired Skull Furnace

2008 ◽  
Vol 39-40 ◽  
pp. 485-488
Author(s):  
Oleg A. Prokhorenko
Keyword(s):  
Mathematical Model ◽  
Physical Properties ◽  
Molten Glass ◽  
Glass Melting ◽  
Model Development ◽  
Melting Process ◽  
Processing Parameters ◽  
Primary Energy ◽  
Glass Temperature ◽  
State Process

The present paper describes an overview of mathematical modeling of the glass melting process inside an open-top skull furnace having DC plasma discharge as the primary energy source. This melting system has been developed by Plasmelt Glass Technologies LLC (Boulder, CO, USA). A mathematical model of intensive glass melting, which is a non-stationary state process, and corresponding software have been developed by modeling team of Laboratory of Glass Properties LLC (LGP). This mathematical model has been created in parallel with the development of the melting process itself. Having a fully operational pilot unit available the Plasmelt team had the possibility to compare behavior of a real melting system with that calculated by the model. Special attention was paid to accuracy of input data on both physical properties of glass and processing parameters. The influence of absorption of radiation in short- and near- IR ranges (0.6 – 2.6 µm) by the molten glass on some key process parameters (throughput and outflow molten glass temperature) has been studied. This work has become possible because of intensive work of the joint team: Ron Gonterman and Mike Weinstein (Plasmelt), Scott Parker (University of Colorado), Oleg Prokhorenko, Sergey Tarakanov, Sergey Chivilikhin, Marina Chistokolova and Roman Eroshkin (LGP) on task formulation, experimental runs, model development, testing and verification, and physical properties studies.

ORGANISM EXPOSURE TO VOLATILE/SOLUBLE HYDROCARBONS FROM CRUDE OIL SPILLS—A FIELD AND LABORATORY COMPARISON

1987 ◽  
Vol 1987 (1) ◽  
pp. 275-288 ◽  
Author(s):  
Clayton D. McAuliffe
Keyword(s):  
Crude Oil ◽  
Water Column ◽  
Oil Spills ◽  
Open Water ◽  
Marine Species ◽  
High Water ◽  
Water Soluble ◽  
Field Exposure ◽  
Near Surface ◽  
Total Oil

ABSTRACT The acute toxicities of the water soluble fraction of crude oils or the aqueous solution of individual hydrocarbons were compared with the field exposure concentrations to dissolved hydrocarbons under crude oil slicks and emulsion plumes from chemically dispersed slicks. The exposures were related by expressing LC50 values for differing times and varying concentrations as a product (mean concentration × time = ppm-hours). Field exposures to soluble hydrocarbons under oil slicks on open water or in plumes of efficiently dispersed slicks are very low (from 150 to 1 million times lower) compared with exposures to cause half mortality for more than 50 marine species. This is so because oil slicks are thin, generally with average thickness between 0.1 and 0.01 mm. A high water-to-oil ratio limits the concentration of total oil to 10 to 100 ppm in the top meter of water, and 1 to 10 in 10 m. The soluble and volatile hydrocarbons quickly evaporate to the atmosphere from the slick or from near-surface waters. The field exposure of organisms in the water column is low initially and is transitory. Thus, oil spills and the chemical dispersion of slicks are unlikely to have measurable adverse effects on larval, juvenile, or adult marine organisms in the water column.

EFFECTS OF CHEMICAL DISPERSANTS AND MINERAL FINES ON PARTITIONING OF PETROLEUM HYDROCARBONS IN NATURAL SEAWATER

2008 ◽  
Vol 2008 (1) ◽  
pp. 633-638 ◽  
Author(s):  
Kenneth Lee ◽  
Zhengkai Li ◽  
Thomas King ◽  
Paul Kepkay ◽  
Michel C Boufadel ◽  
...  
Keyword(s):  
Crude Oil ◽  
Water Column ◽  
Petroleum Hydrocarbons ◽  
Oil Spills ◽  
Suspended Sediments ◽  
Bulk Water ◽  
Natural Seawater ◽  
Dispersed Oil ◽  
Aliphatic And Aromatic Hydrocarbons ◽  
Mineral Aggregates

ABSTRACT The interaction of chemical dispersants and suspended sediments with crude oil influences the fate and transport of oil spills in coastal waters. Recent wave tank studies have shown that dispersants facilitate the dissipation of oil droplets into the water column and reduces the particle size distribution of oil-mineral aggregates (OMAs). In this work, baffled flasks were used to carry out a controlled laboratory experimental study to define the effects of chemical dispersants and mineral fines on the partitioning of crude oil, major fractions of oil, and petroleum hydrocarbons from the surface to the bulk water column and the sediment phases. The dissolved and dispersed oil in the aqueous phase and OMA was characterized using an Ultraviolet Fluorescence Spectroscopy (UVFS). The distribution of major fractions of crude oil (the alkanes, aromatics, resins, and asphaltenes) was analyzed by thin layer chromatography coupled to flame ionized detection (TLC/FID); aliphatic and aromatic hydrocarbons were analyzed by gas chromatography and mass spectrometry (GC/MS). The results suggest that chemical dispersants enhanced the transfer of oil from the surface to the water column as dispersed oil, and promoted the formation of oil-mineral aggregates in the water column. Interaction of chemically dispersed oil with suspended particular materials needs to be considered in order to accurately assess the environmental risk associated with chemical oil dispersant use in particle-rich nearshore and esturine waters. The results from this study indicate that there is not necessarily an increase in sedimentation of oil in particle rich water when dispersants are applied.

Mathematical Model of Flat Surface Machining Inaccuracies due to Elastic Strains of Technological System

2018 ◽  
pp. 1-14 ◽  
Author(s):  
I. I. Kravchenko
Keyword(s):  
Mathematical Model ◽  
Vector Field ◽  
Model Development ◽  
Technological System ◽  
Mutual Arrangement ◽  
Real Surface ◽  
Main Bearing ◽  
Flat Surfaces ◽  
Internal Surfaces ◽  
Elastic Strains

The paper considers the mathematical model development technique to build a vector field of the shape deviations when machining flat surfaces of shell parts on multi-operational machines under conditions of anisotropic rigidity in technological system (TS). The technological system has an anisotropic rigidity, as its elastic strains do not obey the accepted concepts, i.e. the rigidity towards the coordinate axes of the machine is the same, and they occur only towards the external force. The record shows that the diagrams of elastic strains of machine units are substantially different from the circumference. The issues to ensure the specified accuracy require that there should be mathematical models describing kinematic models and physical processes of mechanical machining under conditions of the specific TS. There are such models for external and internal surfaces of rotation [2,3], which are successfully implemented in practice. Flat surfaces (FS) of shell parts (SP) are both assembly and processing datum surfaces. Therefore, on them special stipulations are made regarding deviations of shape and mutual arrangement. The axes of the main bearing holes are coordinated with respect to them. The joints that ensure leak tightness and distributed load on the product part are closed on these surfaces. The paper deals with the analytical construction of the vector field F, which describes with appropriate approximation the real surface obtained as a result of modeling the process of machining flat surfaces (MFS) through face milling under conditions of anisotropic properties.

Separation of Methane from Shuttle Tanker Vents Gases by Adsorption on a Polyurethane/Zeolite Membrane

2017 ◽  
Vol 733 ◽  
pp. 42-46
Author(s):  
Habiba Shehu ◽  
Edidiong Okon ◽  
Edward Gobina
Keyword(s):  
Carbon Dioxide ◽  
Physical Properties ◽  
Crude Oil ◽  
Deep Water ◽  
Separation Factor ◽  
Gas Permeation ◽  
Zeolite Membrane ◽  
Alumina Support ◽  
Molar Flux

Shuttle tankers are becoming more widely used in deep water installations as a means of transporting crude oil to storage plants and refineries. The emissions of hydrocarbon vapours arise mainly during loading and offloading operations. Experiments have been carried out on the use of polyurethane/zeolite membrane on an alumina support for the separation of methane from carbon dioxide and oxygen. The physical properties of the membrane were investigated by FTIR. Single gas permeation tests with methane, propane, oxygen and carbon dioxide at a temperature of 293 K and pressure ranging from 0.1 to 1.0 x 10-5 Pa were carried out. The molar flux of the gases through the membrane was in the range of 3 x 10-2 to 1 x 10-1 molm-2s-1. The highest separation factor of CH4/CO2 and CH4/O2 and CH4/C3H8 was determined to be 1.7, 1.7 and 1.6 respectively.

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