Integral models for bubble, droplet, and multiphase plume dynamics in stratification and crossflow

We present the development and validation of a numerical modeling suite for bubble and droplet dynamics of multiphase plumes in the environment. This modeling suite includes real-fluid equations of state, Lagrangian particle tracking, and two different integral plume models: an Eulerian model for a double-plume integral model in quiescent stratification and a Lagrangian integral model for multiphase plumes in stratified crossflows. Here, we report a particle tracking algorithm for dispersed-phase particles within the Lagrangian integral plume model and a comprehensive validation of the Lagrangian plume model for single- and multiphase buoyant jets. The model utilizes literature values for all entrainment and spreading coefficients and has one remaining calibration parameter (Formula presented.), which reduces the buoyant force of dispersed phase particles as they approach the edge of a Lagrangian plume element, eventually separating from the plume as it bends over in a crossflow. We report the calibrated form (Formula presented.), where b is the plume half-width, and r is the distance of a particle from the plume centerline. We apply the validated modeling suite to simulate two test cases of a subsea oil well blowout in a stratification-dominated crossflow. These tests confirm that errors from overlapping plume elements in the Lagrangian integral model during intrusion formation for a weak crossflow are negligible for predicting intrusion depth and the fate of oil droplets in the plume. The Lagrangian integral model has the added advantages of being able to account for entrainment from an arbitrary crossflow, predict the intrusion of small gas bubbles and oil droplets when appropriate, and track the pathways of individual bubbles and droplets after they separate from the main plume or intrusion layer

Dynamics of live oil droplets and natural gas bubbles in deep water

Explaining the dynamics of gas-saturated live petroleum in deep water remains a challenge. Recently, Pesch et al. (Environ. Eng. Sci. 2018, 35, 289−299) reported laboratory experiments on methane-saturated oil droplets under emulated deep-water conditions, providing an opportunity to elucidate the underlying dynamical processes. We explain these observations with the Texas A&M Oil spill/Outfall Calculator (TAMOC), which models the pressure-, temperature-, and composition-dependent interactions between: oil-gas phase transfer; aqueous dissolution; and densities and volumes of liquid oil droplets, gas bubbles, and two-phase droplet-bubble pairs. TAMOC reveals that aqueous dissolution removed >95% of the methane from ~3.5-mm live oil droplets within 14.5 min, prior to gas bubble formation, during the experiments of Pesch et al. Additional simulations indicate that aqueous dissolution, fluid density changes, and gas-oil phase transitions (ebullition, condensation) may all contribute to the fates of live oil and gas in deep water, depending on the release conditions. Illustrative model scenarios suggest that 5-mm diameter gas bubbles released at <470 m water depth can transport methane, ethane, and propane to the water surface. Ethane and propane can reach the water surface from much deeper releases of 5-mm diameter live oil droplets, during which ebullition occurs at water depths of <70 m

Methane seeps - A desktop study

We have conducted a literature review and a simplified one-dimensional modelling study on the fate of methane bubbles and dissolved methane in the water column originating from methane seeps. From the literature review, we have found that the physical processes describing the rise and dissolution of methane bubbles are relatively well understood, and several studies use very similar modelling approaches. When it comes to biodegradation rates for dissolved methane in seawater, there is far more uncertainty, and published values span a range of six orders of magnitude. These rates may also depend on local conditions, and on methane concentrations, as higher concentrations allow methane-degrading bacteria to exist in larger numbers. On the topic of how methane seeps contribute to the acidification of the ocean, we find that the amounts of methane released from seeps are probably too small to make a significant difference, compared to other sources of CO2, such as the dissolution of atmospheric CO2 into the ocean. Modelling of seeps at three different depths (50 m, 120 m and 300 m) indicates that almost all of the methane released as bubbles will dissolve into the water column before the bubbles reach the surface. For the dissolved methane, we have used the diffusion-reaction equation to investigate how much biodegrades, and how much is released to the atmosphere via mass transfer across the sea surface. To reflect the uncertainty in published biodegradation rates, we conducted a parameter study, running simulations for biodegradation half-lives ranging from 10 to 1000 days. The model results indicate that for methane seeps at 50 m depth most of the methane will reach the atmosphere, for seeps at 120 m depth, more than half the methane will reach the atmosphere if the biodegradation half-life is longer than about 50 days, and for seeps at 300 m depth, more than half of the methane will reach the atmosphere if the half-life is longer than about 300 days. In these studies, we have assumed a relatively well-mixed water column during the winter season.publishedVersio

Simulations of subsea CO2 leakage scenarios

Subsea carbon dioxide leakages from geological storage complexes and transmission lines may pose a threat to the marine ecosystem in their vicinity. For high leakage flow rates (100 kg/s), buoyant dynamic plumes will form and, in shallow water depths (100-300 m) such as in continental shelves, they may reach the water surface thereby releasing gases to the atmosphere. Here, we present simulations of subsea releases of CO2 at varying scales, such as seeps, point source plumes and line source plumes, and we discuss their behaviors. The simulated release conditions and water depths are representative of potential storage area on the Norwegian Continental Shelf. Simulations are performed with the TAMOC model, a multiphase-integral plume modeling suite developed and validated for subsea gas and oil releases

Simulations of Subsea CO2 Leakage Scenarios

Subsea carbon dioxide leakages from geological storage complexes and transmission lines may pose a threat to the marine ecosystem in their vicinity. For high leakage flow rates (100 kg/s), buoyant dynamic plumes will form and, in shallow water depths (100-300 m) such as in continental shelves, they may reach the water surface thereby releasing gases to the atmosphere. Here, we present simulations of subsea releases of CO2 at varying scales, such as seeps, point source plumes and line source plumes, and we discuss their behaviors. The simulated release conditions and water depths are representative of potential storage area on the Norwegian Continental Shelf. Simulations are performed with the TAMOC model, a multiphase-integral plume modeling suite developed and validated for subsea gas and oil releases

Methane seeps - A desktop study

We have conducted a literature review and a simplified one-dimensional modelling study on the fate of methane bubbles and dissolved methane in the water column originating from methane seeps. From the literature review, we have found that the physical processes describing the rise and dissolution of methane bubbles are relatively well understood, and several studies use very similar modelling approaches. When it comes to biodegradation rates for dissolved methane in seawater, there is far more uncertainty, and published values span a range of six orders of magnitude. These rates may also depend on local conditions, and on methane concentrations, as higher concentrations allow methane-degrading bacteria to exist in larger numbers. On the topic of how methane seeps contribute to the acidification of the ocean, we find that the amounts of methane released from seeps are probably too small to make a significant difference, compared to other sources of CO2, such as the dissolution of atmospheric CO2 into the ocean. Modelling of seeps at three different depths (50 m, 120 m and 300 m) indicates that almost all of the methane released as bubbles will dissolve into the water column before the bubbles reach the surface. For the dissolved methane, we have used the diffusion-reaction equation to investigate how much biodegrades, and how much is released to the atmosphere via mass transfer across the sea surface. To reflect the uncertainty in published biodegradation rates, we conducted a parameter study, running simulations for biodegradation half-lives ranging from 10 to 1000 days. The model results indicate that for methane seeps at 50 m depth most of the methane will reach the atmosphere, for seeps at 120 m depth, more than half the methane will reach the atmosphere if the biodegradation half-life is longer than about 50 days, and for seeps at 300 m depth, more than half of the methane will reach the atmosphere if the half-life is longer than about 300 days. In these studies, we have assumed a relatively well-mixed water column during the winter season

Oil spill modeling in deep waters: Estimation of pseudo-component properties for cubic equations of state from distillation data

Highlights • Pseudo-components for high-pressure deep-water oil spill models • Estimation of Peng-Robinson EOS parameters for distillation-cut pseudo-components • Modeling of the non-ideal chemistry of hydrocarbons in deep waters • New correlations to calculate chemical properties of petroleum fractions • Validated with 614 oils from the ADIOS oil library Abstract Deep-water oil spills represent a major, localized threat to marine ecosystems. Multi-purpose computer models have been developed to predict the fate of spilled oil. These models include databases of pseudo-components from distillation cut analysis for hundreds of oils, and have been used for guiding response action, damage assessment, and contingency planning for marine oil spills. However, these models are unable to simulate the details of deep-water, high-pressure chemistry. We present a new procedure to calculate the chemical properties necessary for such simulations that we validate with 614 oils from the ADIOS oil library. The calculated properties agree within 20.4% with average values obtained from data for measured compounds, for 90% of the chemical properties. This enables equation-of-state calculations of dead oil density, viscosity, and interfacial tension. This procedure enables development of comprehensive oil spill models to predict the behavior of petroleum fluids in the deep sea

Petroleum Dynamics in the Sea and Influence of Subsea Dispersant Injection during \u3cem\u3eDeewater Horizon\u3c/em\u3e

During the Deepwater Horizon disaster, a substantial fraction of the 600,000-900,000 tons of released petroleum liquid and natural gas became entrapped below the sea surface, but the quantity entrapped and the sequestration mechanisms have remained unclear. We modeled the buoyant jet of petroleum liquid droplets, gas bubbles, and entrained seawater, using 279 simulated chemical components, for a representative day (June 8, 2010) of the period after the sunken platform\u27s riser pipe was pared at the wellhead (June 4-July 15). The model predicts that 27% of the released mass of petroleum fluids dissolved into the sea during ascent from the pared wellhead (1,505 m depth) to the sea surface, thereby matching observed volatile organic compound (VOC) emissions to the atmosphere. Based on combined results from model simulation and water column measurements, 24% of released petroleum fluid mass became channeled into a stable deep-water intrusion at 900- to 1,300-m depth, as aqueously dissolved compounds (∼23%) and suspended petroleum liquid microdroplets (∼0.8%). Dispersant injection at the wellhead decreased the median initial diameters of simulated petroleum liquid droplets and gas bubbles by 3.2-fold and 3.4-fold, respectively, which increased dissolution of ascending petroleum fluids by 25%. Faster dissolution increased the simulated flows of water-soluble compounds into biologically sparse deep water by 55%, while decreasing the flows of several harmful compounds into biologically rich surface water. Dispersant injection also decreased the simulated emissions of VOCs to the atmosphere by 28%, including a 2,000-fold decrease in emissions of benzene, which lowered health risks for response workers

Fungal diversity notes 603–708: taxonomic and phylogenetic notes on genera and species

This is the sixth in a series of papers where we bring collaborating mycologists together to produce a set of notes of several taxa of fungi. In this study we introduce a new family Fuscostagonosporaceae in Dothideomycetes. We also introduce the new ascomycete genera Acericola, Castellaniomyces, Dictyosporina and Longitudinalis and new species Acericola italica, Alternariaster trigonosporus, Amarenomyces dactylidis, Angustimassarina coryli, Astrocystis bambusicola, Castellaniomyces rosae, Chaetothyrina artocarpi, Chlamydotubeufia krabiensis, Colletotrichum lauri, Collodiscula chiangraiensis, Curvularia palmicola, Cytospora mali-sylvestris, Dictyocheirospora cheirospora, Dictyosporina ferruginea, Dothiora coronillae, Dothiora spartii, Dyfrolomyces phetchaburiensis, Epicoccum cedri, Epicoccum pruni, Fasciatispora calami, Fuscostagonospora cytisi, Grandibotrys hyalinus, Hermatomyces nabanheensis, Hongkongmyces thailandica, Hysterium rhizophorae, Jahnula guttulaspora, Kirschsteiniothelia rostrata, Koorchalomella salmonispora, Longitudinalis nabanheensis, Lophium zalerioides, Magnibotryascoma mali, Meliola clerodendri-infortunati, Microthyrium chinense, Neodidymelliopsis moricola, Neophaeocryptopus spartii, Nigrograna thymi, Ophiocordyceps cossidarum, Ophiocordyceps issidarum, Ophiosimulans plantaginis, Otidea pruinosa, Otidea stipitata, Paucispora kunmingense, Phaeoisaria microspora, Pleurothecium floriforme, Poaceascoma halophila, Periconia aquatica, Periconia submersa, Phaeosphaeria acaciae, Phaeopoacea muriformis, Pseudopithomyces kunmingnensis, Ramgea ozimecii, Sardiniella celtidis, Seimatosporium italicum, Setoseptoria scirpi, Torula gaodangensis and Vamsapriya breviconidiophora. We also provide an amended account of Rhytidhysteron to include apothecial ascomata and a J+ hymenium. The type species of Ascotrichella hawksworthii (Xylariales genera incertae sedis), Biciliopsis leptogiicola (Sordariomycetes genera incertae sedis), Brooksia tropicalis (Micropeltidaceae), Bryochiton monascus (Teratosphaeriaceae), Bryomyces scapaniae (Pseudoperisporiaceae), Buelliella minimula (Dothideomycetes genera incertae sedis), Carinispora nypae (Pseudoastrosphaeriellaceae), Cocciscia hammeri (Verrucariaceae), Endoxylina astroidea (Diatrypaceae), Exserohilum turcicum (Pleosporaceae), Immotthia hypoxylon (Roussoellaceae), Licopolia franciscana (Vizellaceae), Murispora rubicunda (Amniculicolaceae) and Doratospora guianensis (synonymized under Rizalia guianensis, Trichosphaeriaceae) were re-examined and descriptions, illustrations and discussion on their familial placement are given based on phylogeny and morphological data. New host records or new country reports are provided for Chlamydotubeufia huaikangplaensis, Colletotrichum fioriniae, Diaporthe subclavata, Diatrypella vulgaris, Immersidiscosia eucalypti, Leptoxyphium glochidion, Stemphylium vesicarium, Tetraploa yakushimensis and Xepicula leucotricha. Diaporthe baccae is synonymized under Diaporthe rhusicola. A reference specimen is provided for Periconia minutissima. Updated phylogenetic trees are provided for most families and genera. We introduce the new basidiomycete species Agaricus purpurlesquameus, Agaricus rufusfibrillosus, Lactifluus holophyllus, Lactifluus luteolamellatus, Lactifluus pseudohygrophoroides, Russula benwooii, Russula hypofragilis, Russula obscurozelleri, Russula parapallens, Russula phoenicea, Russula pseudopelargonia, Russula pseudotsugarum, Russula rhodocephala, Russula salishensis, Steccherinum amapaense, Tephrocybella constrictospora, Tyromyces amazonicus and Tyromyces angulatus and provide updated trees to the genera. We also introduce Mortierella formicae in Mortierellales, Mucoromycota and provide an updated phylogenetic tree