Hydrocarbon Mixtures Research Articles

Role of Hydroxyl Groups in Zn-containing Nanosized MFI Zeolite for the Photocatalytic Oxidation of Methane.

The effective conversion of methane to a mixture of more valuable hydrocarbons and hydrogen under mild conditions is a significant scientific and practical challenge. Here, we synthesized Zn-containing nanosized MFI zeolite for direct oxidation of methane in the presence of H2O and air. The presence of the surface hydroxyl groups on nanosized MFI-type zeolite and their significant reduction in the Zn-containing nanosized MFI zeolite were confirmed with Infrared Fourier Transform (FTIR) spectroscopy. Incorporation of zinc atoms into the framework of nanosized MFI zeolite is revealed by Nuclear Magnetic Resonance, X-ray Diffraction and UV-Vis Spectroscopy. Unexpectedly, pure silica MFI zeolite exhibited the highest photocatalytic performance. Our findings demonstrated that large number of isolated silanol groups and silanol nests increase the formation of ⋅OH, and enhance the productivity of oxygenate compounds and C2H6, while the Zn incorporated into the zeolite framework or attached to the silanol nests of the nanosized zeolites are less efficient. A mechanism of photocatalytic methane oxidation is proposed. These findings provide insights into the development of active nanosized zeolite photocatalysts with an extended amount of surface hydroxyl groups that can play a key role in photocatalytic methane conversion.

Polyaromatic hydrocarbons of small reservoirs of the Tomsk region

Relevance. The assessment of the state of natural waters includes the determination of a number of physico-chemical indicators, on the basis of which various indices and classifications are developed. However, they do not take into account a number of pollutants that have a significant impact on the state of the reservoir, for example, polyaromatic hydrocarbons. The article considers some aspects of determining priority pollutants, which include polyaromatic hydrocarbons, according to environmental hazard criteria: toxicity, carcinogenicity, prevalence, frequency of occurrence, source of origin (anthropogenic or natural). Hydrochemical parameters such as pH, dissolved oxygen content, biological oxygen consumption (BPK5), and ion content are taken into account to determine water quality. An attempt was made to assess the impact of polyaromatic hydrocarbons on the ecological state of water bodies and to take into account their contribution to changes in the values of the water pollution index. All these data prove the relevance of the study. Aim. To establish the composition of polyaromatic hydrocarbons in the surface waters of small reservoirs of the Tomsk region to assess anthropogenic load and to show the relationship with the indices of natural water quality. Methods. Extraction, liquid adsorption chromatography, high-performance liquid chromatography, capillary electrophoresis, amperometry, titrimetry. Results. Small lakes of the Tomsk region were studied for the content of 13 polyaromatic hydrocarbons. The authors have carried out the identification by high-performance liquid chromatography with fluorimetric detection. The total content of polyaromatic compounds in the studied surface water samples varies from 0.37 to 0.54 mcg/l. In the polyaromatic hydrocarbons mixture in aqueous samples, there is an increased content of light 2–3 nuclear polyarenes with better solubility (naphthalene, fluorene and phenanthrene), as well as benz[a]anthracene. The content of inorganic components represented by cations and anions does not exceed the maximum permissible concentrations. The water pollution index was calculated; all lakes are moderately polluted, closer to polluted. The paper demonstrates the dependence of the water pollution index coefficient on the content of high-molecular polyaromatic hydrocarbons and the ratio of high-molecular to low-molecular polyaromatic hydrocarbons. It is shown that the higher the value of the water pollution index coefficient, the higher the proportion of difficult-to-oxidize components in surface waters.

Toxicity of crude oil: a systematic review of the acute impacts on Cnidaria

Cnidarians are ecosystem engineers that play a fundamental role in food webs. However, they are increasingly threatened by anthropogenic activities, such as oil spills, which can cause acute sublethal effects and in some cases, mortality. The literature on this theme is limited and fragmented, with diverse objectives and methodologies, making it challenging to identify consistent patterns and knowledge gaps. This article aims to provide a systematic review of the acute impacts of crude oil and petroleum hydrocarbons on members of the Phylum Cnidaria, to synthesize and integrate the available data. The research followed the PRISMA 2020 guidelines, and employed the search terms: “crude oil” AND “acute” AND (Cnidaria OR coral), along with the names of each Cnidarian class. The search was restricted to articles published in English from 2013 to 2023, excluding studies that did not directly address the core topic. The number of records collected was relatively low, with only 30 articles identified from 20 studies. The highest number of publications occurred in 2022, and the USA was the most represented country. The Class Anthozoa, particularly corals (Order Scleractinia) was the most studied. Research focused on the effects of crude oil on gametes, embryos, larvae and adults, with most studies examining adult organisms. The majority (56.6%), utilized mixtures of crude oil hydrocarbons, while a smaller proportion (36.6%) focused on pure aromatic hydrocarbons. Most experiments employed Water Accommodated Fractions (36.6%) and continuous flow system (20%). The most common exposure durations (30%) were 96 and 48h, with exposure times ranging from 18h to several days. There was significant variation in methodological approaches, underscoring the need for standardized protocols. Research on adult cnidarians primarily assessed health and morphology, lethality, genetic alterations, and symbiont efficiency. In contrast, studies on early life stages focused on lethality, larval metamorphosis and settlement. Overall, the results indicate that responses vary considerably, particularly concerning exposure time and oil concentration, with sublethal effects at different levels. Further studies incorporating a broader range of species, novel approaches, and the combined effects of elevated temperature and UV radiation are crucial to advancing our understanding of oil impacts on cnidarians.

A Comprehensive Review on Insect Repellent Agents: Medicinal Plants and Synthetic Compounds.

Plant-based repellents have been used for generations as personal protection against mosquitoes. Ethnobotanical studies provide valuable knowledge for developing natural prod-ucts. Commercial repellents with plant-based ingredients are popular, but insufficient studies follow Pesticide Evaluation Scheme WHO guidelines. Further standardized studies are needed to evaluate repellent compounds and develop high-repellency and safe products. Essential Oils (EOs) from aromatic plants have gained popularity as low-risk insecticides due to their low toxicity and short environmental persistence. These plant-derived EOs, produced through steam distillation, have repellent, insecticidal, and growth-reducing effects on various insects. They control phytophagous insects, bite flies, and home and garden insects. US registration is the main hurdle for new EOs. This review explores the use of essential oils from plants as a natural repellent, focusing on their effectiveness and synergistic effects. Essential oils are vol-atile mixtures of hydrocarbons with diverse functional groups, and their effectiveness is linked to monoterpenes and sesquiterpenes. Synergistic effects can improve their effectiveness, and the use of other natural products, like vanillin, can increase protection time. Cymbopogon spp., Ocimum spp., and Eucalyptus spp. are among the most promising plant families.

Rutile-phase Sn-Ti Mixed Oxides as Acid Catalysts for the Condensation of C2-C3 Oxygenated Compounds in Water.

The design of new cost-effective and water-resistant acid catalysts is crucial for valorizingaqueous side-streams to increase the efficiency and competitiveness of bio-refineries in a sustainable way. In this work, Sn-Ti mixed oxides are prepared via a green and scalable co-precipitation method. This synthesis procedure allows obtaining homogeneous rutile-phase Sn-Ti mixed oxides with enhanced textural properties and a higher amount of Lewis acid sites. More importantly, the catalytic behavior of these Sn-Ti mixed oxides is investigated by using an aqueous mixture of C2-C3 representative oxygenated compounds, closer to real industrial conditions and differing from usual individual probe molecules studies performed even in the absence of water. Catalytic experiments combined and correlated with spectroscopic measurements (i.e., XRD, TEM, FT-IR with pyridine adsorption-desorption and N2 adsorption) are performed to better understand the properties of different Sn-Ti catalysts. These materials show promising results in the condensation of light oxygenated compounds present in aqueous fractions. Homogeneous and robust rutile-phase structures with inherent hydrophobic characteristics turn these Sn-Ti materials into active and highly resistant catalysts capable to transform these low-value oxygenated compounds into a mixture of hydrocarbons and aromatics useful for blending with automotive fuels, especially under complex acidic aqueous environments and moderate process conditions.

Synergistic C2H2 Binding Sites in Hydrogen-Bonded Supramolecular Framework for One-Step C2H4 Purification from Ternary C2 Mixture.

Purification of C2H4 from the ternary C2 hydrocarbon mixture in one step is of critical significance but still extremely challenging according to its intermediate physical properties between C2H6 and C2H2. Hydrogen-bonded organic frameworks (HOFs) stabilized by supramolecular interactions are emerging as a new kind of adsorbents that facilitate green separation. However, it remains a problem to efficiently realize the one-step C2H4 purification from C2H6/C2H4/C2H2 mixture because of the low C2H2/C2H4 selectivity. We herein report a robust microporous HOF (termed as HOF-TDCPB) with dense O atoms and aromatic rings distributed on the pore surface which provide C2H6 and C2H2 preferred environment simultaneously. Dynamic breakthrough experiments indicate that HOF-TDCPB can not only obtain high-purity C2H4 from binary C2 mixture, but also firstly realize one-step C2H4 purification from ternary C2H6/C2H4/C2H2 mixture, with the C2H4 productivity of 3.2 L/kg (>99.999 %) for one breakthrough cycle. Furthermore, HOF-TDCPB displays outstanding stability in air, organic solvents and water, which endow it excellent cycle performance even under high-humidity conditions. Theoretical calculations indicate that multiple O sites on pore channels can create synergistic binding sites for C2H2, thus affording overall stronger multipoint interactions.

Synergistic C2H2 Binding Sites in Hydrogen‐Bonded Supramolecular Framework for One‐Step C2H4 Purification from Ternary C2 Mixture

AbstractPurification of C2H4 from the ternary C2 hydrocarbon mixture in one step is of critical significance but still extremely challenging according to its intermediate physical properties between C2H6 and C2H2. Hydrogen‐bonded organic frameworks (HOFs) stabilized by supramolecular interactions are emerging as a new kind of adsorbents that facilitate green separation. However, it remains a problem to efficiently realize the one‐step C2H4 purification from C2H6/C2H4/C2H2 mixture because of the low C2H2/C2H4 selectivity. We herein report a robust microporous HOF (termed as HOF‐TDCPB) with dense O atoms and aromatic rings distributed on the pore surface which provide C2H6 and C2H2 preferred environment simultaneously. Dynamic breakthrough experiments indicate that HOF‐TDCPB can not only obtain high‐purity C2H4 from binary C2 mixture, but also firstly realize one‐step C2H4 purification from ternary C2H6/C2H4/C2H2 mixture, with the C2H4 productivity of 3.2 L/kg (>99.999 %) for one breakthrough cycle. Furthermore, HOF‐TDCPB displays outstanding stability in air, organic solvents and water, which endow it excellent cycle performance even under high‐humidity conditions. Theoretical calculations indicate that multiple O sites on pore channels can create synergistic binding sites for C2H2, thus affording overall stronger multipoint interactions.

Vapor-liquid equilibria of the ternary system of methane + n-decane + n-octacosane at high pressures

Alkane mixture phase equilibria is required for a range of industrial applications, most particularly for the petroleum industries. Mixtures containing light and heavy normal alkanes are of even further significance due to their non-ideal thermodynamic behavior. In this work, for the first time, the ternary system of C1 + C10 + C28 was investigated experimentally to obtain bubble point pressures at various concentrations and temperatures ranging from 373 up to 445 K. The synthetic method of phase equilibrium measurements was utilized, which is known to have high accuracy. The resulting bubble points for the mixtures ranged in pressure from about 3 MPa up to 6 MPa. The data indicated that methane concentrations had the greatest impact, not only on the magnitude of the bubble point pressure, but also on the slope of its temperature trend. The relative concentrations of n-decane and n-octacosane had far less impact on the bubble point curves. The results were also modelled using the Peng–Robinson equation of state, and it was found that this equation has the capability to predict the data with an AARD% of 5.1 %. When temperature-independent binary interaction parameters were optimized to the data, the AARD% reduced to 2.4 %. Although the components vary greatly in size, perhaps the success of the Peng–Robinson equation of state for this mixture could be attributed to the fact that it was developed for hydrocarbon mixtures, and so, a reason for its popularity in the petroleum industries, alongside its simplicity and ease of use.

Benzenoid Aromatics from Renewable Resources.

In this Review, all known chemical methods for the conversion of renewable resources into benzenoid aromatics are summarized. The raw materials that were taken into consideration are CO2; lignocellulose and its constituents cellulose, hemicellulose, and lignin; carbohydrates, mostly glucose, fructose, and xylose; chitin; fats and oils; terpenes; and materials that are easily obtained via fermentation, such as biogas, bioethanol, acetone, and many more. There are roughly two directions. One much used method is catalytic fast pyrolysis carried out at high temperatures (between 300 and 700 °C depending on the raw material), which leads to the formation of biochar; gases, such as CO, CO2, H2, and CH4; and an oil which is a mixture of hydrocarbons, mostly aromatics. The carbon selectivities of this method can be reasonably high when defined small molecules such as methanol or hexane are used but are rather low when highly oxygenated compounds such as lignocellulose are used. The other direction is largely based on the multistep conversion of platform chemicals obtained from lignocellulose, cellulose, or sugars and a limited number of fats and terpenes. Much research has focused on furan compounds such as furfural, 5-hydroxymethylfurfural, and 5-chloromethylfurfural. The conversion of lignocellulose to xylene via 5-chloromethylfurfural and dimethylfuran has led to the construction of two large-scale plants, one of which has been operational since 2023.

Numerical and Performance Analysis of R290 Heat Pump Driven Air Conditioning System for Heating and Cooling

The demand for heating and air conditioning is rising due to rapidly changing climatic conditions. The market for heat pumps and air conditioning systems is seeing a steady increase in low global warming potential. There is a growing need to use environment-friendly refrigerants. Contemporary Refrigerants (HCFCs) such as those found in heat pump air conditioning systems have the potential to cause global warming and ozone depletion. Using more environmentally friendly refrigerants, including hydrocarbon and blend refrigerant mixtures, is one way to lower Global Warming Potential (GWP) and Ozone depletion potential. This study examines the performance of several alternative refrigerants, including R32, R134A, R410A, R22 and R290. To examine the performance of R290, theoretical and simulation results are compared for various refrigerants while taking into account several performance parameters, including the refrigerant energy efficiency ratio, mass flow rate, coefficient of performance, cooling capacity and compressor work for One Ton of Refrigeration (1TR) air conditioners. One player with a very low GWP is R290. However, the only drawback is that it can catch fire and is hazardous to use in split-type commercial heat pump air conditioning applications. The environmental and thermo physical properties of R290 are significantly better than those of other materials, according to theoretical and simulation studies utilising Cool Pack software, hence it is a viable replacement.

Yarrowia lipolytica growth, lipids, and protease production in medium with higher alkanes and alkenes

Two strains of Yarrowia lipolytica (CBS 2075 and DSM 8218) were first studied in bioreactor batch cultures, under different controlled dissolved oxygen concentrations (DOC), to assess their ability to assimilate aliphatic hydrocarbons (HC) as a carbon source in a mixture containing 2 g·L−1 of each alkane (dodecane and hexadecane), and 2 g·L−1 hexadecene. Both strains grew in the HC mixture without a lag phase, and for both strains, 30 % DOC was sufficient to reach the maximum values of biomass and lipids. To enhance lipid-rich biomass and enzyme production, a pulse fed-batch strategy was tested, for the first time, with the addition of one or three pulses of concentrated HC medium. The addition of three pulses of the HC mixture (total of 24 g·L−1 HC) did not hinder cell proliferation, and high protease (> 3000 U·L−1) and lipids concentrations of 3.4 g·L−1 and 4.3 g·L−1 were achieved in Y. lipolytica CBS 2075 and DSM 8218 cultures, respectively. Lipids from the CBS 2075 strain are rich in C16:0 and C18:1, resembling the composition of palm oil, considered suitable for the biodiesel industry. Lipids from the DSM 8218 strain were predominantly composed of C16:0 and C16:1, the latter being a valuable monounsaturated fatty acid used in the pharmaceutical industry. Y. lipolytica cells exhibited high intrinsic surface hydrophobicity (> 69 %), which increased in the presence of HC. A reduction in surface tension was observed in both Y. lipolytica cultures, suggesting the production of extracellular biosurfactants, even at low amounts. This study marks a significant advancement in the valorization of HC for producing high-value products by exploring the hydrophobic compounds metabolism of Y. lipolytica.

Influence of reduced graphene oxide layer on sensing characteristics of Co3O4/rGO nanocomposite towards Liquefied Petroleum Gas (LPG)

Liquefied petroleum gas (LPG), a mixture of different hydrocarbons, is a highly inflammable and explosive gas that is harmful to the environment and human health. Thus, it is imperative to fabricate LPG sensors with higher sensitivity, selectivity, stability, and minimal power consumption, functioning at low temperatures. The current study reports on the monitoring and detection of LPG at low functional temperatures using Co3O4-loaded on rGO (rGO-Co) prepared using the hydrothermal method. The microstructural properties of the materials were investigated in detail. The rGO-Co (80 wt%) sensor showed outstanding sensitivity (0.00364 ppm−1) and selectivity toward LPG, as well as a limit of detection of 1 ppm at a temperature of 125 °C. The sensing mechanism showed that an even distribution of Co3O4 throughout the rGO layers, serving as efficient sites for the adsorption and desorption of LPG molecules, was associated with enhanced gas-sensing capabilities. Furthermore, the response to LPG detection was significantly influenced by the combination of the finite spherical nanoparticles with increased pore sizes between them and reduced energy band gaps. Thus, the novel improvement of the sensor towards LPG detection was linked to the ohmic connection formed between rGO and Co3O4 forming a p-p heterojunction at the interface. Additionally, the coupling of Co-O-C bonds validated by high-temperature X-ray diffraction and X-ray photoelectron spectroscopy provided extra active sites from Co3+ for effective LPG adsorption. The sensing mechanism induced by the loading of Co3O4 on the rGO surface was also deliberated.

Accurate measurement of Soret coefficients in binary hydrocarbons mixtures based on composite methods

The Soret effect is a significant factor in various scenarios, with thermodiffusion in binary systems serving as a common method for the study. Most research focuses rarely on the distribution characteristics of components in diffusion systems; and Soret coefficients in the porous media could not be obtained by typical methods based on the thermodiffusion column, which are particularly important in the field of oil and gas development. Moreover, experiments on ground conditions have struggled to determine the Soret coefficient accurately due to the convective effect caused by gravity differentiation. The thermodiffusion behavior of n-pentane (C5) and n-heptane (C7) binary mixtures in both bulk and porous media conditions have been investigated, aiming to provide corrected coefficients that mitigate the influence of gravity using theoretical derivation. A new method was proposed to calculate the Soret coefficients in this work by establishing a model based on gas chromatography technology. Dynamic variation of component concentration along the path was studied, and the corresponding Soret coefficients were calculated and analyzed in parallel. The results indicate that the concentration and temperature exhibit a logarithmic relationship with the distance from the heat source. The Soret coefficient values obtained from measurements in porous media are closer to the theoretically corrected values, which do not account for gravity effects. Additionally, as the permeability decreases, the counteracting effect of porous media on convection becomes more pronounced. Therefore, it presents a novel method for accurately measuring the Soret coefficient that ignores convection to some extent.

Epigenetic transgenerational inheritance of toxicant exposure-specific non-coding RNA in sperm.

Environmentally induced epigenetic transgenerational inheritance of phenotypic variation and disease susceptibility requires the germ cell (sperm or egg) transmission of integrated epigenetic mechanisms involving DNA methylation, histone modifications, and non-coding RNA (ncRNA) actions. Previous studies have demonstrated that transgenerational exposure and disease-specific differential DNA methylation regions (DMRs) in sperm are observed and that ncRNA-mediated DNA methylation occurs. The current study was designed to determine if transgenerational exposure-specific ncRNAs exist in sperm. Specifically, toxicants with distinct mechanisms of action including the fungicide vinclozolin (anti-androgenic), pesticide dichlorodiphenyltrichloroethane (estrogenic), herbicide atrazine (endocrine disruptor at cyclic adenosine monophosphate level), and hydrocarbon mixture jet fuel (JP8) (aryl hydrocarbon receptor disruptor) were used to promote transgenerational disease phenotypes in F3 generation outbred rats. New aliquots of sperm, previously collected and used for DNA methylation analyses, were used in the current study for ncRNA sequencing analyses of nuclear RNA. Significant changes in transgenerational sperm ncRNA were observed for each transgenerational exposure lineage. The majority of ncRNA was small noncoding RNAs including piwi-interacting RNA, tRNA-derived small RNAs, microRNAs, rRNA-derived small RNA, as well as long ncRNAs. Although there was some overlap among the different classes of ncRNA across the different exposures, the majority of differentially expressed ncRNAs were exposure-specific with no overlapping ncRNA between the four different exposure lineages in the transgenerational F3 generation sperm nuclear ncRNAs. The ncRNA chromosomal locations and gene associations were identified for a small number of differential expressed ncRNA. Interestingly, an overlap analysis between the transgenerational sperm DMRs and ncRNA chromosomal locations demonstrated small populations of overlapping ncRNA, but a large population of non-overlapping ncRNAs. Observations suggest that transgenerational sperm ncRNAs have both exposure-specific populations within the different classes of ncRNA, as well as some common populations of ncRNAs among the different exposures. The lack of co-localization of many of the ncRNAs with previously identified transgenerational DMRs suggests a distal integration of the different epigenetic mechanisms. The potential use of ncRNA analyses for transgenerational toxicant exposure assessment appears feasible.

Improvement of the delumping method in order to obtain detailed characteristics of the fluid

In compositional modeling, the phase characteristics and behavior of reservoir fluids are calculated using the equation of state. To simplify the calculations and speed them up, the components of the heptane plus fraction (C7+) are grouped into pseudo-components. However, after this procedure, the results of compositional modelling of the reservoir containing the pseudo-components need to be delumped so that they can be used in surface models. It follows from this that the problem lies in the fact that the grouped composition cannot be applied to the modeling of ground structures. The object of the study is Kazakhstani oil, on the example of which a detailed component composition was obtained by analytical delumping based on reduction parameters. In laboratory conditions, the component composition of oil, and other fluid properties were determined. The study presents the results that prove the importance of applying the delumping algorithm in the context of compositional modeling. The results obtained analytically correspond quite accurately to the numerical calculations of the PVTsim software and laboratory experiments. A comparison of existing methods showed a difference of 5 %, which suggests that delumping is an excellent method for describing and obtaining a detailed composition of the hydrocarbon mixture. In practice, the results of the detailed composition of hydrocarbons can be used for the design of refineries. Also, the findings from this research can enhance the planning and design of surface facilities, particularly when developed under reservoir conditions where the pressure exceeds the saturation pressure

Methanogenesis coupled hydrocarbon biodegradation enhanced by ferric and sulphate ions

Bioremediation provides an environmentally sound solution for hydrocarbon removal. Although bioremediation under anoxic conditions is slow, it can be coupled with methanogenesis and is suitable for energy recovery. By altering conditions and supplementing alternative terminal electron acceptors to the system to induce syntrophic partners of the methanogens, this process can be enhanced. In this study, we investigated a hydrocarbon-degrading microbial community derived from chronically contaminated soil. Various hydrocarbon mixtures were used during our experiments in the presence of different electron acceptors. In addition, we performed whole metagenome sequencing to identify the main actors of hydrocarbon biodegradation in the samples. Our results showed that the addition of ferric ions or sulphate increased the methane yield. Furthermore, the addition of CO2, ferric ion or sulphate enhanced the biodegradation of alkanes. A significant increase in biodegradation was observed in the presence of ferric ions or sulphate in the case of all aromatic components, while naphthalene and phenanthrene degradation was also enhanced by CO2. Metagenome analysis revealed that Cellulomonas sp. is the most abundant in the presence of alkanes, while Ruminococcus and Faecalibacterium spp. are prevalent in aromatics-supplemented samples. From the recovery of 25 genomes, it was concluded that the main pathway of hydrocarbon activation was fumarate addition in both Cellulomonas, Ruminococcus and Faecalibacterium. Chloroflexota bacteria can utilise the central metabolites of aromatics biodegradation via ATP-independent benzoyl-CoA reduction.Key points• Methanogenesis and hydrocarbon biodegradation were enhanced by Fe3+ or SO42−• Cellulomonas, Ruminococcus and Faecalibacterium can be candidates for the main hydrocarbon degraders• Chloroflexota bacteria can utilise the central metabolites of aromatics degradationGraphical

A Comprehensive Approach to Modeling Air Injection-Based Enhanced Oil Recovery Processes

Summary Modeling of air-injection-based processes for enhanced oil recovery (EOR) is a challenging task, mostly due to the complexity of the chemical reactions taking place. Also, the applicability of currently available kinetic models is limited to the reservoir systems they were originally developed for. The objective of this study is to derive a general chemical reaction framework that could be used to develop a kinetic model for a variety of crude oils (i.e., light or heavy oils). The work is based on the modeling of high-pressure ramped temperature oxidation (HPRTO) experiments, and combustion tube (CT) tests, performed on two different oil systems: a volatile oil that is near critical at reservoir conditions (44 °API), and a bitumen sample (10 °API). The HPRTO test is a kinetic experiment that intends to mimic the flow conditions within the reservoir and allows the determination of kinetic parameters of the different reactions. On the other hand, the CT test is meant to provide quantitative information on the combustion performance that can be expected in the field. Therefore, a kinetic model was derived for each of the cases based on the history match of an HPRTO experiment. The resulting model was validated by history matching a CT test for each of the oils. An important feature of these experiments is that they were performed at representative reservoir pressure conditions. The modeling approach chosen is an extension of the methodology originally proposed by Belgrave et al. in 1993, which is arguably the most comprehensive kinetic model available in the air injection literature. However, their model was developed from experiments performed on Athabasca bitumen, and it fails to represent the high-pressure air injection process as it occurs in light oil reservoirs, which are typically encountered at higher pressure conditions. For example, Belgrave’s model is based on the deposition and combustion of semisolid residue commonly known as “coke,” which is rarely present during the combustion of light oils at high pressure. As in Belgrave’s model, this study also describes the original composition of the oil in terms of maltenes and asphaltenes. The main difference lies in the presence and importance of oxygen-induced cracking reactions, as well as the combustion of a liquid-vapor flammable hydrocarbon mixture that is generated by cracking and oxidation reactions, which take place in the gas phase. Also, a unique feature of these simulations is that, apart from history-matching traditional variables such as thermocouple temperatures, fluid recovery, and produced gas composition, they also capture changes in the physical properties of the produced oil, such as viscosity and density, as well as the amount of the residual phases in the post-test core. This enhancement to Belgrave’s reactions allows modeling the air injection process in cases where coke is not the main source of fuel, such as in high-pressure light oil reservoirs. This work changes a paradigm deeply rooted in the original in-situ combustion (ISC) theory, by deriving a general chemical reaction framework that is used to develop a kinetic model for two crude oils, which are at opposite ends of the density spectrum. This allows the consolidation of a new and comprehensive general theory for the description of the ISC process as applied to oil reservoirs. Moreover, as the pseudocomponents representing the fuel are not present in the original oil, the method is not limited to a fluid characterization in terms of maltenes and asphaltenes but could potentially be applied along with any type of characterization of the original oil.

Water-accommodated fractions of heavy and light oils impact DNA integrity, embryonic development, and immune system of Japanese medaka at early life stages.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants generally found in complex mixtures. PAHs are known to cause pleiotropic effects on living organisms, including developmental defects, mutagenicity, carcinogenicity and immunotoxicity, and endocrine disruptions. The main goal of this study is to evaluate the toxicity of water-accommodated fractions (WAFs) of oils in two life stages of the Japanese medaka, larvae and juveniles. The deleterious effects of an acute exposure of 48h to two WAFs from Arabian light crude oil (LO) and refined oil from Erika (HO) were analyzed in both stages. Relevant endpoints, including ethoxy resorufin-O-deethylase (EROD) activity, DNA damage (Comet assay), photomotor response, and sensitivity to nervous necrosis virus (NNV) infection, were investigated. Larvae exposed to both oil WAFs displayed a significant induction of EROD activity, DNA damage, and developmental anomalies, but no behavioral changes. Deleterious effects were significantly increased following exposure to 1 and 10μg/L of LO WAFs and 10μg/L of HO WAFs. Larval infection to NNV induced fish mortality and sharply reduced reaction to light stimulation. Co-exposure to WAFs and NNV increased the mortality rate, suggesting an impact of WAFs on fish defense capacities. WAF toxicity on juveniles was only observed following the NNV challenge, with a higher sensitivity to HO WAFs than to LO WAFs. This study highlighted that environmentally realistic exposure to oil WAFs containing different compositions and concentrations of oil generated high adverse effects, especially in the larval stage. This kind of multi-marker approach is particularly relevant to characterize the toxicity fingerprint of environmental mixtures of hydrocarbons and PAHs.

Blending biomass-based liquid biofuels for a circular economy: Measuring and predicting density for biodiesel and hydrocarbon mixtures at high pressures and temperatures by machine learning approach

Circular economy is an efficient approach to deal with the rapidly increasing demand for energy and its environmental impact. It involves switching to renewable and sustainable energy sources. By providing an alternative to traditional energy resources, biodiesel promotes a circular economy paradigm that embraces renewable energies rather than fossil fuels. As an alternative to fossil fuels, liquid biodiesel helps to improve energy efficiency and reduce pollution. Furthermore, blending biodiesel has proven to be economically and environmentally viable. Knowledge of the thermodynamic properties of biodiesel, such as densities and coefficients of expansivity and compressibility, plays an important role in understanding and determining the behavior of the fuel under different operating conditions. The blend densities of Soybean Oil Biodiesel (SOB) with hexane and Waste Cooking Oil Biodiesel (WCOB) with heptane in four volume ratios were experimentally studied. An Anton Paar vibrating tube densimeter HPM DMA has been used for accurate measurements of densities of the biofuels and their blends. Density measurements were performed at temperatures ranging from 298.15 K to 393.15 K, and pressures between 0.1 MPa and 140 MPa. This work also aims to develop accurate prediction models of the properties of biodiesel blends under various conditions, such as changes in temperature and pressure, which are essential for optimizing energy production processes and engine performance. In this context, the dataset was first investigated with Tait Equation of State (Eos) to determine thermodynamic parameters which including isothermal compressibility and isobaric expansivity. It showed generally low standard deviations. Furthermore, these new experimental densities were also modeled with Artificial Neural Network (ANN) as a machine learning method. This paper models proved that the machine learning method is a suitable tool to model the thermo-physical characteristics of liquid fuels. The findings of this study have the potential to provide valuable guidance to engine engineering applications developers regarding operating conditions and the selection of suitable biodiesel for their system.

Understanding the Hazards of Hexane and Short-Term Exposure to Air Contaminated with Hexane Affects the Nervous System and can Cause Dizziness

Abstract: The term ‘hydrocarbon’ is self-explanatory which means compounds of carbon and hydrogen only. Hydrocarbons play a key role in our daily life. You must be familiar with the terms ‘LPG’ and ‘CNG’ used as fuels. LPG is the abbreviated form of liquified petroleum gas whereas CNG stands for compressed natural gas. Another term ‘LNG’ (liquified natural gas) is also in news these days. This is also a fuel and is obtained by liquifaction of natural gas. Petrol, diesel and kerosene oil are obtained by the fractional distillation of petroleum found under the earth’s crust. Coal gas is obtained by the destructive distillation of coal. Natural gas is found in upper strata during drilling of oil wells. The gas after compression is known as compressed natural gas. LPG is used as a domestic fuel with the least pollution. Kerosene oil is also used as a domestic fuel but it causes some pollution. Automobiles need fuels like petrol, diesel and CNG. Petrol and CNG operated automobiles cause less pollution. All these fuels contain mixture of hydrocarbons, which are sources of energy. Hydrocarbons are also used for the manufacture of polymers like polythene, polypropene, polystyrene etc. Higher hydrocarbons are used as solvents for paints. They are also used as the starting materials for manufacture of many dyes and drugs. Thus, you can well understand the importance of hydrocarbons in your daily life. In this unit, you will learn more about hydrocarbons