Oil Discharge Research Articles

Impact of Harmonic Voltage on the Partial Discharge Properties of Eco-Friendly Nanofluid

The Insulation is crucial in transformers to maintain electrical isolation between components and windings, ensuring safe and efficient operation. Mineral oil acts as both insulation and coolant in transformers. It is a substance that does not naturally degrade and can persist in the environment for an extended period if accidentally released. Therefore, Sunflower oil is used as a substitute for mineral oil. However, harmonic distortion is a common issue in power systems, leading to increased dielectric loss and partial discharge activity, ultimately causing insulation failure and equipment damage. Hence, it is vital to analyze the partial discharge performance of pure Sunflower oil under varying harmonic AC voltages to ensure the reliable operation of electrical devices. The study examines the partial discharge characteristics of a sunflower oil-based nanofluid under harmonic AC voltages, which is a blend of pure sunflower oil and SiO2 nanoparticles. Two nanofluid mixtures were created, one with a 0.01% mass ratio and the other with 0.05% sunflower oil. Various PD characteristics were evaluated, including Partial Discharge significance, starting voltage, duration of increase, maximum amplitude, Phase-Resolved PD sample, and frequency and time graphs of the Partial Discharge signal. All tests were carried out under IEC regulations. A comparison was made between the outcomes of Nano blended sunflower oil and natural sunflower edible oil. Experiments were conducted on partial discharges in Sunflower oil using specific harmonic superimposed AC Voltages, utilizing the third and fifth harmonics. The findings reveal that: a) PDIV value decreases with increasing harmonic order when using AC voltage with superimposed harmonics, b) PD characteristics are closely related to the voltage waveform, and the addition of Silica to sunflower oil results in reduced PD amplitude, pulse duration, and time duration compared to pure sunflower oil.

Locating Insulation Defects in HV Substations Using HFCT Sensors and AI Diagnostic Tools.

In general, a high voltage (HV) substation can be made up of multiple insulation subsystems: an air insulation subsystem (AIS), gas insulation subsystem (GIS), liquid insulation subsystem (power transformers), and solid insulation subsystem (power cables), all of them with their grounding structures interconnected and linked to the substation earth. Partial discharge (PD) pulses, which are generated in a HV apparatus belonging to a subsystem, travel through the grounding structures of the others. PD analyzers using high-frequency current transformer (HFCT) sensors, which are installed at the connections between the grounding structures, are sensitive to these traveling pulses. In a substation made up of an AIS, several non-critical PD sources can be detected, such as possible corona, air surface, or floating discharges. To perform the correct diagnosis, non-critical PD sources must be separated from critical PD sources related to insulation defects, such as a cavity in a solid dielectric material, mobile particles in SF6, or surface discharges in oil. Powerful diagnostic tools using PD clustering and phase-resolved PD (PRPD) pattern recognition have been developed to check the insulation condition of HV substations. However, a common issue is how to determine the subsystem in which a critical PD source is located when there are several PD sources, and a critical one is near the boundary between two HV subsystems, e.g., a cavity defect located between a cable end and a GIS. The traveling direction of the detected PD is valuable information to determine the subsystem in which the insulation defect is located. However, incorrect diagnostics are usually due to the constraints of PD measuring systems and inadequate PD diagnostic procedures. This paper presents a diagnostic procedure using an appropriate PD analyzer with multiple HFCT sensors to carry out efficient insulation condition diagnoses. This PD procedure has been developed on the basis of laboratory tests, transient signal modeling, and validation tests. The validation tests were carried out in a special test bench developed for the characterization of PD analyzers. To demonstrate the effectiveness of the procedure, a real case is also presented, where satisfactory results are shown.

The relationship between power of arc discharge in transformer oil and peak value of the shock wave

The relationship between power of arc discharge in transformer oil and peak value of the shock wave

Deep Learning-Based Detection of Oil Spills in Pakistan’s Exclusive Economic Zone from January 2017 to December 2023

Oil spillages on a sea’s or an ocean’s surface are a threat to marine and coastal ecosystems. They are mainly caused by ship accidents, illegal discharge of oil from ships during cleaning and oil seepage from natural reservoirs. Synthetic-Aperture Radar (SAR) has proved to be a useful tool for analyzing oil spills, because it operates in all-day, all-weather conditions. An oil spill can typically be seen as a dark stretch in SAR images and can often be detected through visual inspection. The major challenge is to differentiate oil spills from look-alikes, i.e., low-wind areas, algae blooms and grease ice, etc., that have a dark signature similar to that of an oil spill. It has been noted over time that oil spill events in Pakistan’s territorial waters often remain undetected until the oil reaches the coastal regions or it is located by concerned authorities during patrolling. A formal remote sensing-based operational framework for oil spills detection in Pakistan’s Exclusive Economic Zone (EEZ) in the Arabian Sea is urgently needed. In this paper, we report the use of an encoder–decoder-based convolutional neural network trained on an annotated dataset comprising selected oil spill events verified by the European Maritime Safety Agency (EMSA). The dataset encompasses multiple classes, viz., sea surface, oil spill, look-alikes, ships and land. We processed Sentinel-1 acquisitions over the EEZ from January 2017 to December 2023, and we thereby prepared a repository of SAR images for the aforementioned duration. This repository contained images that had been vetted by SAR experts, to trace and confirm oil spills. We tested the repository using the trained model, and, to our surprise, we detected 92 previously unreported oil spill events within those seven years. In 2020, our model detected 26 oil spills in the EEZ, which corresponds to the highest number of spills detected in a single year; whereas in 2023, our model detected 10 oil spill events. In terms of the total surface area covered by the spills, the worst year was 2021, with a cumulative 395 sq. km covered in oil or an oil-like substance. On the whole, these are alarming figures.

Adsorption of dissolved gases (CO, H2, CO2) produced by partial discharge in converter transformer oil by CuO(1, 2) and Ag2O(1, 2) clusters doped with MoTe2: A DFT study

Density functional theory (DFT) was used to analyze the effect of (CuO)n, (Ag2O)n (n=1, 2) cluster-doped MoTe2 on the three gases (CO, H2 and CO2) adsorption performance and characteristics. MoTe2 has large bond length and low binding energy, which can simultaneously achieve high sensitivity to target molecules and excellent reversibility at room temperature. By analyzing the modified MoTe2, compared with the initial MoTe2, the reduced energy band structure of band gap, the increased adsorption energy, more charge transfer, and the increased conductivity of DOS, all reflect that the doping of metal oxides enhances the adsorption and sensing performance of MoTe2 for the three gases. The adsorption capacity of CuO-MoTe2 and (Ag2O)2-MoTe2 for the three gases is: CO>H2>CO2, while the adsorption capacity of (CuO)2-MoTe2 and Ag2O-MoTe2 for the three gases is: CO>CO2>H2. Finally, the adsorption effects of the four modifications were compared and feasibility analyzed through molecular orbitals, recovery time, sensitivity and work function, and corresponding conclusions were drawn. The results of this study provide a theoretical basis for detecting dissolved gases in oil generated by partial discharge of converter transformers.

Hydrophobic silicone modified membranes for efficient oil/water separation: Synthesis, fabrication and application

Oil leakage and discharge of organic wastewater have not only threatened the ecosystem, but also greatly aggravated water scarcity. Efficient separation of oil–water mixture has become a global challenge. To solve this issue, various hydrophobic membranes with special wettability have been developed in past decades. Among them, the hydrophobic silicone-modified membranes have attracted much attention due to their low cost, easy processing and large-scale production. Herein, recent progresses of hydrophobic silicone-modified membranes for oil–water separation are reviewed. Basic mechanisms and principles for efficient oil–water separation are presented as a starting point for the discussion. Then, according to the modified silicone polymers or molecules, we give a detail description of their synthesis and briefly introduce the main reactions with the substrate, the typical grafting strategy and fabricating methods. Subsequently, the performance and oil–water application of various hydrophobic membranes modified silicone are introduced. Finally, some problems and challenges faced by silicone modification are summarized and present, and their future development is also prospected.

Preparation and tribological properties of porous polyimide modified by graphene

PurposeThe purpose of this article is to prepare graphene/polyimide composite materials for use as bearing cage materials, improving the friction and wear performance of bearing cages.Design/methodology/approachThe oil absorption and discharge tests were conducted to evaluate the oil content properties of the materials, while the mechanical properties were analyzed through cross-sectional morphology examination. Investigation into the tribological behavior and wear mechanisms encompassed characterization and analysis of wear trace morphology in PPI-based materials. Consequently, the influence of varied graphene nanoplatelets (GN) concentrations on the oil content, mechanical and tribological properties of PPI-based materials was elucidated.FindingsThe composites exhibit excellent oil-containing properties due to the increased porosity of PPI-GN composites. The robust formation of covalent bonds between GN and PPI amplifies the adhesive potency of the PPI-GN composites, thereby inducing a substantial enhancement in impact strength. Notably, the PPI-GN composites showed enhanced lubrication properties compared to PPI, which was particularly evident at a GN content of 0.5 Wt.%, as evidenced by the minimization of the average coefficient of friction and the width of the abrasion marks.Practical implicationsThis paper includes implications for elucidating the wear mechanism of the polyimide composites under frictional wear conditions and then to guide the optimization of oil content and tribological properties of polyimide bearing cage materials.Originality/valueIn this paper, homogeneously dispersed PPI-GN composites were effectively synthesized by introducing GN into a polyimide matrix through in situ polymerization, and the lubrication mechanism of the PPI composites was compared with that of the PPI-GN composites to illustrate the composites’ superiority.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0415

Research on Prediction Methods for Eccentric Wear of the Slipper Pair in Axial Piston Pumps and Lubrication Performance Analysis

Abstract The axial piston pump (APP) is the core power component of hydraulic systems. Its friction pair wear can cause the degradation of piston pump performance until the function is completely lost or the service life is terminated. The slipper pair, prone to wear failure, is selected as the research object in this paper. The prediction method for the eccentric wear of the slipper pair is established, and the gradual change rules of the performance with wear accumulation are explored. The micro-surface rough peak contact and the stress state of the slipper pair are analyzed, and the mixed lubrication model of the slipper pair is established based on the elastohydrodynamic lubrication (EHL) model of the slipper pair. Grid discretization of a sealing belt of the slipper pair is carried out based on two-body abrasive wear and Archard adhesive wear models to improve the prediction method for eccentric wear of the slipper pair. The effectiveness of the proposed method is verified by a surface morphology analysis of the worn slipper. The results showed that the wear depth and wear width of the outer edge of the slipper bottom surface are positively correlated with the oil discharge pressure and the inclination angle of the swashplate, and negatively correlated with the rotational speed and the dynamic oil viscosity. The outer edge of the slipper is wedged after eccentric wear, and the hydrodynamic effect of the lubricating oil film of the slipper pair is enhanced. Hence, proper wear can improve the lubrication performance of the slipper pair.

Numerical Modelling and Prediction of Oil Slick Dispersion and Horizontal Movement at Bornholm Basin in Baltic Sea

This paper presents an original approach to predicting oil slick movement and dispersion at the water surface. Special emphasis is placed on the impact of evolving hydro-meteorological conditions and the thickness of the oil spill layer. The main gap addressed by this study lies in the need for a comprehensive understanding of how changing environmental conditions and oil thickness interact to influence the movement and dispersion of oil slicks. By focusing on this aspect, this study aims to provide valuable insights into the complex dynamics of oil spill behaviour, enhancing the ability to predict and mitigate the environmental impacts of such incidents. Self-designed software was applied to develop and modify previously established mathematical probabilistic models for predicting changes in the shape of the oil trajectory. First, a semi-Markov model of the process is constructed, and the oil thickness is analysed at the sea surface over time. Next, a stochastic-based procedure to forecast the horizontal movement and dispersion of an oil slick in diverse hydro-meteorological conditions considering a varying oil layer thickness is presented. This involves determining the trajectory and movement of a slick domain, which consists of an elliptical combination of domains undergoing temporal changes. By applying the procedure and program, a short-term forecast of the horizontal movement and dispersion of an oil slick provided its trajectory at the Bornholm Basin of the Baltic Sea within two days. The research results obtained are preliminary prediction results, although the approach considered in this paper can help responders understand the scope of the problem and mitigate the effects of environmental damage if the oil discharge reaches sensitive ecosystems. Finally, further perspectives of this research are given.

Enhanced Removal of Hydrocarbons from Crude Oil Sludge through Phytoremediation with Biosurfactant-producing Rhizobacteria

Discharge of crude oil (or its products) during the extracting, refining, and transporting into the environment have caused serious environmental distress due to their highly hydrophobic resistance, and persistence in nature and very difficult to be remediated from the environment. Therefore, an environmentally conscious approach to enhance the bioavailability (or solubility) of petroleum hydrocarbon pollutants in soil involves the utilization of biosurfactants. Biosurfactants play a crucial role in enhancing the desorption and solubilization of petroleum hydrocarbons, facilitating their assimilation by microorganisms. This research investigated the application of biosurfactant supplementation derived and purified from rhizobacteria of Scirpus grossus, which are capable of producing biosurfactants and degrading hydrocarbons, in the context of phytoremediation. The crude oil sludge used in this study was obtained from an industrial area containing 56,600±3;900 mg/kg of total petroleum hydrocarbon (TPH). The crude oil sludge was inoculated with biosurfactant, sodium dodecyl sulfate (SDS) as commercial surfactant and only with the presence of S. grossus in the vegetated tanks and monitored for 90 days in a greenhouse. The results indicated that the growth of S. grossus with the addition of biosurfactant was improved and new saplings were produced. After a 90-day exposure period, the removal efficiency of TPH from the soil demonstrated significant increases, reaching 90.3%, 84.1%, and 73.7% when treated with biosurfactant+S. grossus, SDS+S. grossus, and S. grossus only respectively. These percentages were notably higher compared to the non-planted control crates (CC) where the removal efficiency was only 17.9%. These results provide evidence that the introduction of biosurfactant through inoculation can elevate the bioavailability of organic pollutants, consequently augmenting their microbial degradation in the soil.

Study on the Inhibition Effect of C6F12O on Charged Particles in the Flame of Transformer Oil Discharge Gas

ABSTRACT The accidental combustion of insulating oil poses a significant risk in the event of transformer failure. The charged particles generated through the combustion ionization reaction exert considerable influence on the combustion speed and stability of the flame. Therefore, the detailed chemical reaction mechanism including neutral matter and charged particle is simplified. The two-dimensional finite rate reaction model is established. The theoretical calculation investigates the suppressive effect of the novel fire extinguishing agent C6F12O on charged particles in the flame resulting from transformer oil decomposition. The analysis encompasses changes in flame temperature, free radicals, and charged particles in the decomposition gas of transformer oil under C6F12O concentrations ranging from 0% to 4%. The findings reveal that the addition of C6F12O exerts a discernible inhibitory effect on the flame temperature of the transformer oil exhaust gas. The large reduction of charged particles in the flame caused by C6F12O is achieved by its consumption of large amounts of O and OH radicals in the flame. It hampers key elementary reactions responsible for charged particle generation. In conclusion, C6F12O demonstrates a pronounced inhibitory effect on charged particles in the flame resulting from transformer oil decomposition.

Flame retardant and superoleophilic polydopamine/chitosan-graft (g)-octanal coated polyurethane foam for separation oil/water mixtures

The discharge of crude petroleum oils and their derivatives poses serious environmental challenges, which can be mitigated through oil/water separation. In this study, polyurethane (PU)/polydopamine (PDA)/chitosan-graft (g)-octanal foam was prepared by immersing of PU foam in PDA and chitosan-g-octanal solutions. The fabricated PU foam exhibited thermal stability, flame retardancy, and hydrophobicity/superoleophilicity. The coated PU foam can selectively absorb heavy and light oils from dynamic and static oil/water mixtures. The maximum sorption capacity for olive oil was found to be as high as 41.48 g/g. PU/PDA/chitosan-g-octanal foam also demonstrated excellent flame retardancy and the ability to quickly extinguish fire, as confirmed by the limiting oxygen index (LOI) test.

Hydrophobic sorbents based on ultrathin polymer fibers for trapping oil products

Relevance. Increasing negative effects of hydrocarbon production on aquatic ecosystems and tightening of legislative norms on discharge of oil and oil product contaminated water into marine waters. Among various methods used to remove oil from aqueous solutions the most appropriate one is adsorption method. It is explained by its high degree of purification, safety, availability, manufacturability, universality of application. Synthetic materials based on ultrafine fibers have optimal characteristics for manufacturing sorbents for oil removal on their basis. However, the large-scale application of these materials is limited by their high cost, complexity of manufacturing, which excludes the secondary use of polymers as feedstock. In this regard, there is a growing need for economically and environmentally effective hydrophobic materials for sorptive treatment of aqueous media from oil and petroleum products. Aim. To determine sorption properties of hydrophobic fibrous materials produced via pneumatic formation for use as effective hydrocarbon sorbents for liquidation of oil spills in sea and water treatment on oil production platforms. Objects. Sorbents based on polypropylene and polyethylene terephthalate ultrafine fibers. Methods. Gravimetric, spectral analysis, transmission electron microscopy, gas chromatography. Results. The paper introduces the results of investigation of sorption properties of untreated ultrafine fibers obtained by pneumatic atomization and modified by microwave radiation. The authors have carried out the comparative analysis of water absorption and the influence of contact time and acidity of the medium on the degree of sorption of samples obtained from hydrophobic polymers. Promising application of sorbents based on polypropylene ultrathin fibers for oil products extraction from aqueous media was revealed. It is established that modification reduces water absorption of polypropylene sorbents and leads to an insignificant decrease in sorption properties due to changes in the supramolecular structure of polypropylene fiber samples.

Effective separation of water-in-oil emulsions using an under-medium superlyophilic membrane with hierarchical pores

Separating water-in-oil emulsions is important in terms of environmental protection and resource recovery. To address the challenges posed by the water–oil interface, superwetting materials have been designed to accomplish separation through filtration and adsorption. Superhydrophobic membranes prevent the permeation of water droplets owing to extreme repellence and their size-sieving abilities. However, their use in remediating water-contaminated oil is limited by high oil viscosities. Meanwhile, in-air superhydrophilic sorbents are rarely employed for the separation of water-in-oil emulsions due to the thermodynamic and kinetic limitations of water adsorption in oil. Herein, the integration of an under-medium superlyophilic membrane with the hierarchical porous structure of wood is presented for filtration-driven selective adsorption of water from surfactant-stabilized (10 g/L) water-in-oil emulsions. Compared to filtration through a natural wood membrane or direct adsorption using an under-oil superhydrophilic wood membrane, the under-medium superlyophilic wood membrane demonstrated high separation efficiencies of > 99.95% even when applied to the regeneration of high-viscosity lubricating (6.3 mPa s) and edible (50.5 mPa s) oils, exhibiting viscosity-dependent fluxes and excellent stability. Moreover, the cost of purifying 200 mL of lubricating oil using the modified wood membrane was much lower than the oil’s market price and required a low energy consumption of ca. 1.72 kWh. Environmental implicationThe ever-growing use of petroleum and industrial/domestic oil products has led to excessive (estimated at a million tons per year) output of waste oils. Because direct discharge of waste oils into the environment causes serious pollution problems, separating water-in-oil emulsions is important in terms of environmental protection and resource recovery. Here filtration-driven water adsorption has been demonstrated to be a feasible method for the remediation of water-contaminated waste oils, even those that are highly viscous.

Start-up characteristics of a R290 rotary compressor for an air source heat pump under low ambient temperature condition

Due to its excellent thermodynamic properties, low GWP refrigerant R290 is found to be promising alternative refrigerant. However, due to its special physical properties, high oil discharge rate and throttle valve blockage may occur for the R290 heat pump system under low temperature start-up conditions. In this paper, the transient characteristics, including the temperature, heat exchange rate, phase change rate, oil discharge rate and the liquid level of the oil sump, of a R290 rotary compressor used in the heat pump system under low temperature conditions are theoretically and experimentally studied. A transient heat and mass transfer model in the compressor is proposed, which considers the phase change of refrigerant in the shell. The experiment was carried out on the start-up characteristics of the compressor and the mathematical model was verified. The results show that high rotation speed and low temperature are the main reasons for the condensation of R290 in the shell. The excessive liquid refrigerant in the shell leads to a high oil discharge rate of up to 22 %. This paper will provide guidance for the use of R290 refrigerant under low temperature conditions.

Hydrophobic Carbon Nitride Nanolayer Enables High-Flux Oil/Water Separation with Photocatalytic Antifouling Ability.

Efficient oil/water separation tackles various issues in occasions of oil leakage and oil discharge, such as environmental pollution, recollection of the oil, and saving the water. Herein, a compact superhydrophobic/superoleophilic graphitic carbon nitride nanolayer coated on carbon fiber networks (CNBA/CF) is designed and synthesized for efficient gravity-driven oil/water separation. The CNBA/CF shows excellent oil absorption and an impressive oil/water filtration separation performance. The flux reaches the state-of-art value of 4.29 × 105 L/m2/h for dichloromethane with separation efficiency up to 99%. Successive oil absorption tests, long-term filtration separation, and harsh conditions experiments confirm the remarkable separation and chemical structure stability of the CNBA/CF filter. Besides, the CNBA/CF demonstrates good photocatalytic antifouling ability thanks to the extended visible light absorption and improved charge separation. This work combines the material surface wettability modulation with a photocatalytic self-cleaning property in the fabrication of efficient oil/water separation materials while overcoming the filter fouling issue.

Degradation, altered microbial community composition, and protein expression in bacterial consortium/fungus inoculated crude oil contaminated loamy soil

Accidental discharge of crude oil due to rupturing of old oil pipelines and blasts in oil refineries leads to contamination of agricultural land/adjacent areas and changes in microbial community and protein expression in the contaminated soil. Our previous study identified a bacterial consortium (Bacillus amyloliquefaciens MW532755+ Pseudomonas sp. MW444887) and a fungus (Aspergillus sydowii KY614299) with crude oil degrading ability. These microorganisms were used in the present investigation to degrade total petroleum hydrocarbon in naturally contaminated loamy soil (25% w/w) collected from the Assam region of India. The half-life of crude oil in uninoculated (T1), bacterial consortium (T2), and fungus-inoculated (T3) soils were 135.9, 47.5, and 58.2 days, respectively. The bacterial consortium and the fungus treatments altered the soil bacterial community and metabolic pathways, evidently from the analyses using metagenomics and predicted functional proteomics. The sequencing analysis using Ion Torrent showed the presence of 287 genera in the oil-polluted and treated soil samples. At the Genus level, abundances of Pseudomonas and Bacilli were observed, and the reads representing those of the Domain Bacteria for uninoculated (T1), bacterial consortium (T2), and fungus (T3) treated soils were 214525, 584054 and 489423, respectively. The predicted functional proteomics analysis for the protein-regulating genes, functional pathways, and protein families showed the presence of diversified pathways responsible for higher metabolic activities (q < 0.05). The quantitative polymerase chain reaction (qPCR) analysis showed that, compared to fungus treatment, bacterial consortium increased the abundance of 16S rRNA gene copies of Archaea, Alphaproteobacteria, and Bacteroidetes and also the gene copies of nitrogen cycling such as nifH (106 to 108) were highest, followed by nirK (104 to 108), amoA (104 to 105), and nirS (104 to 106)The present study suggested that the bacterial consortium as the hydrocarbon degraders was better than fungus and can be used in the future for oil remediation purposes.

Postextraction monitoring of dissolved oxygen in virgin olive oil

AbstractThe issue of the presence of dissolved oxygen (DO) in virgin olive oil (VOO) is neglected in literature. Available information is limited to the extraction stage of the product life cycle, and studies focused on the subsequent stages from extraction to bottling are virtually absent. The present work aims to fill this gap through a dissolved oxygen monitoring experiment performed at industrial scale. Seven different unit‐operations of the routine working procedure of an Italian industrial company specializing in the marketing of VOO were studied: oil discharge from tanker truck; blend formation; oil transferring to filtration; oil transferring to bottling; precoat‐bodyfeed filtration; polishing filtration; bottling. The overall concentration of DO averages to 2.2 mg L–1, while the oil incoming the company was at 1.5 mg L–1. The unit‐operations can be ordered as “mixing‐for‐blend &gt; precoat‐bodyfeed filtration &gt; transfer‐to‐bottling &gt; bottling,” with a decreasing oxygenation effect. Polishing filtration does not determine a significant DO variation. In the immediate term, the increase in DO does not result in oxidative deterioration of the oil, at least detectable with the peroxides value.Practical Applications: The results provide important information for the management of virgin olive oil on an industrial scale in the postproduction stages up to bottling. First, it was clearly demonstrated that bulk transport operations led to oxygenation of the oil. From this point on, the oil underwent further oxygenation, the extent of which depends on the specific processing operation considered. The oxygenation effect of each operation is different, which means that different interventions with varying intensity in terms of complexity and cost could be applied on a case‐by‐case basis to preserve the oil from oxygenation.

An Arctic natural oil seep investigated from space to the seafloor

Due to climate change, decreasing ice cover and increasing industrial activities, Arctic marine ecosystems are expected to face higher levels of anthropogenic stress. To sustain healthy and productive ocean ecosystems, it is imperative to build baseline data to assess future climatic and environmental changes. Herein, a natural oil seep site offshore western Svalbard (Prins Karls Forland, PKF, 80–100 m water depth), discovered using satellite radar images, was investigated using an extensive multiscale and multisource geospatial dataset collected by satellite, aerial, floating, and underwater platforms. The investigated PKF seep area covers roughly a seafloor area of 30,000 m2 and discharges oil from Tertiary or younger source rocks. Biomarker analyses confirm that the oil in the slicks on the sea surface and from the seep on the seafloor have the same origin. Uranium/Thorium dating of authigenic carbonate crusts indicated that the seep had emanated since the Late Pleistocene when ice sheet melting unlocked the hydrocarbons trapped beneath the ice. The faunal communities at the PKF seep are a mix of typical high latitude fauna and taxa adapted to reducing environments. Remarkably, the inhospitable oil-impregnated sediments were also colonized by abundant infaunal organisms. Altogether, in situ observations obtained at the site provide essential insights into the characteristics of high–latitude oil seeps and can be used as a natural laboratory for understanding the potential impacts of human oil discharge into the ocean.

Hammerstein–Wiener Model Identification for Oil-in-Water Separation Dynamics in a De-Oiling Hydrocyclone System

To reduce the environmental impact of offshore oil and gas, the hydrocarbon discharge regulations tend to become more stringent. One way to reduce the oil discharge is to improve the control systems by introducing new oil-in-water (OiW) sensing technologies and advanced control. De-oiling hydrocyclones are commonly used in offshore facilities for produced water treatment (PWT), but obtaining valid control-oriented models of hydrocyclones has proven challenging. Existing control-oriented models are often based on droplet trajectory analysis. While it has been demonstrated that these models can fit steady-state separation efficiency data, the dynamics of these models have either not been validated experimentally or only describe part of the dynamics. In addition to the inlet OiW concentration, they require the droplet size distribution to be measured, which complicates model validation as well as implementation. This work presents an approach to obtain validated nonlinear models of the discharge concentration, separation efficiency, and discharge rate, which do not require the droplet size distribution to be measured. An exhaustive search approach is used to identify control-oriented polynomial-type Hammerstein–Wiener (HW) models of de-oiling hydrocyclones based on concentration measurements from online OiW monitors. To demonstrate the effectiveness of this modeling approach, a PI controller is designed using the Skogestad internal model control (SIMC) tuning rules to control the discharge OiW concentration directly. The identification experiment emulates an offshore PWT system with installed OiW monitors, which is realistic with the legislative incentive to include online OiW discharge measurements. The proposed approach could enable the application of OiW-based control on existing offshore PWT facilities, resulting in improved de-oiling performance and reduced oil discharge.