Compounds In Crude Oil Research Articles

Effect of methyl substituents on the biodegradation of two-ring polycyclic aromatic hydrocarbons in crude oil identified by aerobic biodegradation simulations

Existing studies determining the effects of substituted methyl groups on polycyclic aromatic hydrocarbon biodegradation were mostly limited to an individual compound or a class of compounds. The simultaneous transformation of the multiple series of methyl-substituted two-ring polycyclic aromatic hydrocarbons (61 compounds) in crude oil through laboratory simulations has been examined, including naphthalenes, fluorenes, biphenyls, and dibenzofurans. The biodegradation sequences were in the order of dimethylnaphthalenes > trimethylnaphthalenes > biphenyls > dibenzofurans, tetramethylnaphthalenes > pentamethylnaphthalenes > fluorenes. Polycyclic aromatic hydrocarbon biodegradation was depending on both the number and the position of methyl substituents. For naphthalenes, fluorenes, biphenyls, and dibenzofurans, the more methyl groups in the parent compound, the more resistant it was to biodegradation. Among the polycyclic aromatic hydrocarbons with the same number of methyl groups, the more ortho-methyl substitutes, the more challenging it was to be decomposed. In the case of dimethylnaphthalenes or trimethylnaphthalenes with the same number of methyl and ortho-methyl substituents, their biodegradability reduced as the number of α substituents increased. The number of ortho-methyl substituents had a greater impact than that of α/β substituents. The relative significance of these two factors has not been confirmed in previous studies.

Molecular characterization of non-polar sulfur compounds in the full boiling range crude oil fractions

Organic sulfur compounds (OSCs) are usually the most abundant heteroatomic compounds in crude oils and have very complex molecular composition. Thousands of sulfur-containing compounds have been identified from various petroleum fractions by different techniques. However, complete characterization of sulfur compounds in specific crude oils is rarely reported. In this study, molecular characterization of sulfur compounds in a whole crude oil was carried out with gas chromatographic and mass spectrometric techniques. The crude oil was separated into naphtha (<180 °C), middle distillate (180–350 °C), and the residual (>350 °C) by distillation. The naphtha was directly analyzed by gas chromatography coupled with a sulfur chemiluminescence detector. A methylation/demethylation method was carried out to separate aromatic sulfur compounds (ASCs) and sulfidic sulfur compounds (SSCs) from the middle distillate and the residue. The separated ASCs and SSCs were characterized by GC and mass spectrometry, as well as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). A global distribution of OSCs in the crude oil was obtained by the combination of the analysis results. The type and content of OSCs are significantly different among the distillation fractions. Hydrogen sulfide and mercaptans, accounting for 0.1 % and 1.2 % of the total sulfur content, respectively, mainly distribute in naphtha. SSCs, which are rich in thiadiamondoids, account for 15.5 % of the total sulfur content. ASCs are the most abundant identified species and account for 35.8 % of total sulfur content. Other OSCs such as complex polyheteroatomic compounds occupied 41.0 % of the total sulfur content.

Regiospecific Photochemical Synthesis of Methylchrysenes

Methylated polycyclic aromatic hydrocarbons (PAHs) are suspected to be some of the toxic compounds in crude oil towards marine life and are needed as single compounds for environmental studies. 1-, 3- and 6-methylchrysene (3a,b,c) were prepared as single isomers by photochemical cyclization of the corresponding stilbenoids in the Mallory reaction using stoichiometric amounts of iodine in 82-88% yield. 2-methylchrysene (3d) was prepared by photochemical cyclization where the regioselectivity was controlled by elimination of an ortho-methoxy group under acidic oxygen free conditions in 72% yield. These conditions failed to form 4-methylchrysene from the corresponding stilbenoid. All stilbenoids were made from a common naphthyl Wittig salt and suitably substituted benzaldehydes. We have also demonstrated that methylchrysenes can be oxidized to the corresponding chrysenecarboxylic acids by KMnO4 in modest yields.

Biosurfactant Production from the Biodegradation of n-Paraffins, Isoprenoids and Aromatic Hydrocarbons from Crude Petroleum by Yarrowia lipolytica IMUFRJ 50682

Yarrowia lipolytica is a unique, strictly aerobic yeast with the ability to degrade efficiently hydrophobic substrates. In the present work, we evaluated the degrading potential of Yarrowia lipolytica IMUFRJ 50682, isolated from tropical estuarine water in Rio de Janeiro (Brazil), and the possible biomolecules produced during this process. To investigate which crude oil compounds are degraded by Y. lipolytica IMUFRJ 50682, this microorganism was grown in a medium containing Marlim petroleum (19 °API, American Petroleum Institute gravity) at 28 °C and 160 rpm for 5 days. The residual petroleum was submitted to gas chromatograph-mass spectrometric analysis (GC-MS). The chromatographic fingerprints of the residual petroleum were compared with the abiotic control test incubated in the same conditions. Y. lipolytica assimilates high molecular weight hydrocarbons, such as n-alkanes (C11-C19), isoprenoids (pristane and phytane), aromatics with two or three aromatics rings (naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, phenanthrene, methylphenanthrenes, dimethylphenanthrenes, anthracene). This strain was also capable of consuming more complex hydrocarbons, such as tricyclic terpanes. During this biodegradation, the emulsification index of the culture medium increased significantly, showing that biosurfactant molecules can be produced from this process. Therefore, Y. lipolytica IMUFRJ 50682 showed to be a potential crude oil degrading yeast, which can be used for bioremediation processes and simultaneously produce bioproducts of commercial interest.

Chromatographic Determination of the Concentration of Organochlorine Compounds in Crude Oil and Petroleum Products

Chromatographic Determination of the Concentration of Organochlorine Compounds in Crude Oil and Petroleum Products

Identification and geochemical significance of unusual C24 tetracyclic terpanes in Shahejie Formation source rocks in the Bozhong subbasin, Bohai Bay Basin

C 24 tetracyclic terpanes are common compounds in source rocks and crude oils, and C 24 17,21-secohopane is the most common and widely used source-related indicator. In this study, three unusual C 24 tetracyclic terpanes were detected on the m/z 191 chromatogram of saturated hydrocarbons in the Shahejie Formation source rocks in the Bozhong subbasin. Based on the mass spectra characteristics, diagnostic ion fragments, retention time and comparisons with published literature, three unusual C 24 tetracyclic terpanes were identified as 10β(H)-des-A-oleanane, 10β(H)-des-A-lupane and C 24 des-A-hopane. To the best of our knowledge, this is the first study to detect and publicly report these three compounds in source rock samples from the Shahejie Formation of the Bozhong subbasin, Bohai Bay Basin. The results indicated that 10β(H)-des-A-oleanane and 10β(H)-des-A-lupane likely originated from terrestrial angiosperms, while C 24 des-A-hopane likely originated from prokaryotic organisms. Terrestrial angiosperms provide the material basis for the generation of compounds A and B, and the distribution and concentration of these two compounds are affected by thermal maturity. In the low maturity stage (0.5% < R o < 0.7%), compounds A and B are relatively enriched in the source rocks.

Liquid-liquid extraction of polyaromatic compounds with ionic liquid. A theoretical and experimental approach

Recent legislation worldwide aims to reduce the levels of polyaromatics compounds in lubricant bases due to their harmful effect on health. Ionic liquids have obtained broad interest as green recyclable extractants. Here, we presented new experimental data of liquid-liquid extraction implementing ionic liquids for the removal of aromatics compounds of synthetic crude oil in a 1:1 mass/mass ratio for temperatures ranging from 303.15 to 293.15 K. Selectivity and distribution constant data are obtained to know the extractive potential of each ionic liquid. To support the experimental results, several computational calculations have been performed. First, two predictive thermodynamic models COSMO-SAC and UNIFAC, have been applied, and the reliability of both models has been compared with experimental results. The results show that using UNIFAC is more accurate than using COSMO to predict extraction behavior. Second, the extractive process has been studied using molecular dynamics. This tool allows us to understand better how the extraction process occurs and the molecules’ situation when they reach equilibrium. It is shown that the cation of the ionic liquid is the primary driver of liquid–liquid extraction. In addition, molecular dynamics will enable a qualitative comparison between the performance of ionic liquids and the experimental results. It is a helpful tool to save time and material resources before laboratory experimentation.

Geochemical characteristics and origin of crude oil from Carboniferous volcanic rocks in the Hongche Fault Zone of the Junggar Basin of China

In recent years, significant advances have been made in the exploration of Carboniferous volcanic reservoirs in the Hongche Fault Zone of the Junggar Basin of China, showing good prospects for further exploration. However, the large variation in the physical properties of crude oil and the complex distribution rule inhibit the one-step exploration. In this study, the PM scale of the biodegradation of crude oil and source of crude oil were studied using experimental methods that target the properties, bulk properties and biomarker compounds of crude oil. The exploration potential of crude oil in this area was analysed, and an accumulation model of crude oil was established. Based on the differences in biomarker compounds and the degree of biodegradation, crude oils were divided into four groups and seven subgroups. Additionally, the analysis of the biomarker compounds of crude oil combined with the hydrocarbon-generation history of source rocks showed that there were at least two periods of oil charging in this area. The first period was the late Triassic, with crude oil derived from the P1f source rock. Owing to the strong tectonic activity during the late Indosinian movement, the oil reservoirs were distributed in the footwall of the fault zone, and the oil in the reservoir exhibited different degrees of biodegradation, forming crude oils of subgroup I1, II and III1. The second period was Cretaceous, during which the P1f source rock was in the natural gas generation stage, and the P2w source rock was at a mature stage. A small part of the crude oil formed by the P2w source rock migrated to the Carboniferous reservoirs and mixed with the crude oil formed by the earlier P1f source rock, resulting in crude oils of subgroups I2, III2, and IV2. The crude oil in the studied area originated from the source rocks in the sag during the peak of oil generation. As tectonic activity approached stability in the latter period, it is speculated that there may be well-preserved primary oil and gas reservoirs in the footwall and slope areas of the fault, making these potential exploration sites.

Novel Research on the Use of Multi-Wall Carbon Nanotubes Functionalized with Copper Oxide Nanoparticles in the Adsorptive Desulphurization of Crude Oil: Laboratory Research

Crude oil is known as liquid hydrocarbon, which is formed as a result of the metamorphosis of organic matter on earth. Crude oil is a complex mixture containing paraffin, naphthenes, olefins, aromatic compounds and a small but significant amount of sulphur. During refining crude oil; air pollutants such as COx, SOx and NOx, NH3, H2S, mercaptans, carbonyl sulfide and heavy metals are released. With the legal regulations made in many countries of the world, it obliges the use of environmentally friendly fuels containing less SOx and aromatic compounds. For this reason, an increasing number of studies are being carried out to reduce the number of sulphur compounds in crude oil as much as possible. For the same reason, in this study; firstly CuONPs and MWCNTs were synthesized separately, secondly MWCNTs were decorated with CuONPs the by the CVD method, and the third was characterized by SEM and XPS. Finally, 0.02 to 0.1 g of CuONPs/MWCNTs and MWCNTs were added separately to the crude oil and adsorptive desulphurization was performed with a contact time of 60 and 120 min. As a result of the experimental study, it has been determined that the desulphurization efficiency varies between 2.47% and 5.44%.

Efficient degradation of hydroquinone by a metabolically engineered Pseudarthrobacter sulfonivorans strain.

Pseudarthrobacter sulfonivorans strain Ar51 can degrade crude oil and multi-substituted benzene compounds efficiently at low temperatures. However, it cannot degrade hydroquinone, which is a key intermediate in the degradation of several other compounds of environmental importance, such as 4-nitrophenol, g-hexachlorocyclohexane, 4-hydroxyacetophenone and 4-aminophenol. Here we co-expressed the two subunits of hydroquinone dioxygenase from Sphingomonas sp. strain TTNP3 with different promoters in the strain Ar51. The strain with 2 hdnO promoters exhibited the strongest hydroquinone catabolic activity. However, in the absence of antibiotic selection this ability to degrade hydroquinone was lost due to plasmid instability. Consequently, we constructed a hisD knockout strain, which was unable to synthesise histidine. By introducing the hisD gene onto the plasmid, the ability to degrade hydroquinone in the absence of antibiotic selection was stabilised. In addition, to make the strain more stable for industrial applications, we knocked out the recA gene and integrated the hydroquinone dioxygenase genes at this chromosomal locus. This strain exhibited the strongest activity in catabolizing hydroquinone, up to 470mg/L in 16h without antibiotic selection. In addition, this activity was shown to be stable when the strain has cultured in medium without antibiotic selection after 20 passages.

Risks of increment of concentrations of sulfur compounds in Iraqi crude oil, gasoline and kerosene

Estimating the concentration of sulphur compounds in crude oil and its products such as gasoline and kerosene is necessary because of environmental legislation and determinants developed by government organizations regulating sulphur levels in oil and its derivatives. Sulphur compounds found in crude oil and its products are a major problem, causing many environmental and health risks as a result of the use of gasoline as fuel for cars and kerosene as fuel for household heaters, resulting in the emission of these compounds in the form of oxides, affecting the environment and health. This study was conducted to estimate the concentration of sulphur compounds in crude oil and distillation products represented by gasoline and kerosene and to show how different the concentration of sulphur compounds in crude oil is than in gasoline and kerosene. In this study, gas chromatography technology was used. This method applies to distillation products, gasoline fuel, kerosene and other petroleum liquids. This study was conducted in basra oil company's quality control laboratories to estimate the concentration of sulphur compounds in crude oil, gasoline and kerosene.

Use of Maca Powder (Lepidium meyenii) as Feed Additive in Diets of Laying Quails at Different Ages: Its Effect on Performance, Eggshell Quality, Serum, Ileum, and Bone Properties.

Simple SummaryQuail has become a popular poultry species, and it is usually used for egg production in Asia and for meat production in Europe and America. In laying quails, aging negatively affects productive performance, egg parameters, and reproductive hormones, just as it affects their bones and digestive systems. Farmers who raise quails suffer great losses due to this fact. There are several nutrients and bioactive substances in Maca with positive effects on hormones and digestive health, which makes it an excellent option for reducing the effects of aging. This study specifies the benefits of Maca powder on aging quails’ diet. The experimental data indicate that adding 1 g/kg Maca powder to a quail’s diet significantly improved eggshell, ileum, and bone traits that deteriorate with age, without affecting performance. Adding 2 g/kg Maca powder to a quail’s diet also significantly reduced serum cholesterol levels. Incorporating Maca powder into the diet of aged birds could reduce the negative effects of aging.Using additives can reduce the negative effects of aging on factors affecting profitability, such as the availability of nutrients, production, and egg quality. Maca is an herbaceous plant rich in protein, crude oil, essential acids, and pharmacological compounds. Maca has positive effects on different health parameters. In this study, the effect of adding Maca powder to the diets of young and old laying quails at the end of the 10-week trial was investigated. In total, 150 laying Japanese quails (Coturnix japonica) (209.1 ± 10.0 g) were randomly distributed to a 2 × 3 factorial arrangement with two ages (10 weeks and 30 weeks) and three Maca powder levels (0, 1, or 2 g/kg), with five subgroups per treatment. According to the study, eggshell quality, total cholesterol, triglyceride, progesterone, and testosterone concentrations of serum were lower in old quail than in young quail, while egg weight, feed intake, and follicle-stimulating hormone increased significantly as quail aged. (p < 0.05). Furthermore, aging negatively affected the histomorphology of the ileum and cortical bone thickness (p < 0.05). Additional findings show that adding 1 g/kg Maca powder to the diet of quail significantly improved eggshell, ileum, and bone traits that deteriorate with age, without affecting performance, and adding 2 g/kg Maca powder to the diet significantly reduced serum total cholesterol levels (p < 0.05). Incorporating Maca powder into the diet of aged birds could reduce the negative effects of aging.

Characterization of the Compounds in Crude Oil That Preferentially Bind to Kaolinite

Chemically enhanced oil recovery (cEOR) is an expensive endeavor that yields modest levels of oil recovery. In order to make it economically viable, an improved understanding of the process is needed. For example, knowledge of the types of compounds in crude oil that are strongly bound to reservoir surfaces would facilitate the design of more efficient cEOR formulations. In this research study, the fractionation step of the previously published distillation, precipitation, and fractionation mass spectrometry (MS) method was utilized to determine the types of compounds in crude oil that are strongly or weakly bound to kaolinite, a prevalent clay mineral found in many oil reservoirs. The results obtained using high-resolution MS experiments revealed that the average molecular weight and the number of aromatic rings were similar for both the strongly and weakly bound compounds. On the other hand, hydrocarbons with no heteroatoms were ∼2.5 times more abundant in the strongly bound compounds than in the nonbound compounds, while heteroatom-containing compounds were more abundant in the nonbound compounds. An analogous binding study performed on a model compound mixture corroborated the above findings that nonpolar compounds prefer to bind to kaolinite than polar compounds. These results suggest that more valuable oil components (nonpolar hydrocarbons) remain in the reservoirs after water flooding, and therefore, cEOR efforts with the appropriate formulation could increase the economic feasibility of the process. The method described herein should also be applicable for the characterization of compounds that bind strongly to different types of mineral surfaces, and the role of temperature, salinity, and pH is studied.

Computer-aided Degradation Susceptibility Study of Crude Oil Compounds at Bacillus subtilis Protein Target

Certain bacteria and fungi have been associated with the oxidative degradation of hydrocarbons and hydrocarbon derivatives in soil and water contaminated by crude oil spilling in these ecosystems. The binding affinity of hydrocarbons and hydrocarbon derivatives in a crude oil sample on the cysteine dioxygenase of Bacillus subtilis was studied using computational methods. The study was aimed to validate the claim of the efficient use of this organism in crude oil remediation and to determine the selectivity of the compounds in the crude by this bacterium enzyme. The compounds in the studied crude oil sample were identified by gas chromatography-mass spectrometry. Straight chain hydrocarbons were the least selected class of compounds with binding free energy ranging between –2.9 kcal/mol to –3.1 kcal/mol. The straight-chain hydrocarbon derivatives containing carbonyl and hydroxyl groups formed the middle class of compounds selected by the enzyme with binding free energy ranging between – 3.3 kcal/mol to –3.7 kcal/mol. The best binding free energies (–3.8 kcal/mol to –5.1 kcal/mol) were obtained with the poly-branched hydrocarbons and the cyclic compounds. The amounts of the poly-branched and cyclic compounds in the crude oil sample suggested that cysteine dioxygenase of B. subtilis would show about 28 % efficiency in the bioremediation of environments polluted by crude oil of this composition.

Swelling Behavior of Lipophilic Polyelectrolyte Gels in Organic Solvents−Water or Sea Water Binary Mixtures

AbstractThe recovery of crude oil and volatile organic compounds (VOCs) spilt in the environment is an intractable problem for environmental scientists. In this paper, a new lipophilic polyelectrolyte gel as an absorbent for various volatile chemical compounds is demonstrated. It is prepared by radical copolymerization of an acrylate monomer with an ionic group, tetraalkylammonium tetraarylborate, octadecyl acrylate, and a crosslinker, dipropylene glycol diacrylate, in the presence of a radial initiator. Investigation of the swelling behavior for the mixtures of water or aqueous salts reveals that the gel shows similar swelling behavior to those for pure organic solvents. On the other hand, the swelling degree in THF‐water mixture is lower than that of pure THF, because THF and water are miscible to each other, and the presence of a small amount of water in THF reduces the compatibility of the gel and THF. The salting‐out effect can separate the THF‐water mixture to form a biphasic system and recover the high swelling ability of the gel. The swelling behavior in the mixture of water‐organic solvents systems provides a new insight for designing VOC and oil absorbents in various environmental conditions, especially in hydrosphere such as seas and lakes.

Using Adsorption as Means to Treat Water Pollution

Background: Water is the source of life form and this crucial source is continuously being polluted through variety of human activities and from natural sources. Many methods have been used to treat water from these pollutants with different degrees of success; one of the most promising techniques is adsorption. Adsorption have been used extensively with variety of adsorbents range from the expensive activated carbon to cheap plant waste. &#x0D; Aim of study: This review provides a scope on the adsorption process and the factors affect the adsorption, types of adoption, isotherm studies and models as well as some examples on the past studies conducted to eliminate various types of contaminants such as chemical dyes, heavy metals and crude oil and other aromatic compounds.

Molecular Characterization of Polar Compounds in Crude Oil Affecting Sandstone Wettability Revealed by Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometry

Summary Knowing the composition, molecular size, and structure of polar compounds in crude oil that affect sandstone wettability is a prerequisite for a better understanding of oil/rock/brine interactions and for better application of enhanced oil recovery (EOR) techniques to increase recovery factors and improve the economic efficiency of field development. The nitrogen-, sulfur-, and oxygen-containing polar compounds in crude oil are key factors for sandstone wettability changes. In this study, an outcrop sandstone core selected from Jurassic formation in Sichuan Basin, China, was aged by crude oil to restore the wettability after being cleaned by hot Soxhlet extraction with an azeotropic solvent mixture of methanol and dichloromethane (MDC, vol/vol = 7:93). Then, Amott-Harvey experiments that were conducted by combining spontaneous imbibition and forced displacement steps of coreflooding were performed to characterize sandstone wettability after it was cut into four core blocks. The wettability index (IA-H) of four core blocks from the inlet to outlet of oil flooding were −0.523, 0.214, −0.087, and −0.861, respectively, which illustrated different degrees of sandstone wettability. The extracts of three sequential hot Soxhlet extraction steps of four core blocks were analyzed by gas chromatography-mass spectrometry (GC-MS) and high-resolution Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) combined with electrospray ionization (ESI) in negative ion mode. Almost no polar compounds were detected in the n-hexane extracts, and a total of seven classes of different polar molecular compounds—namely, N1, N1O1, N1S1, O1, O2, O3, and O4—were detected in dichloromethane (DCM) and MDC extracts. The relative abundances of the N1S1 and O1 classes in the extracts of DCM and MDC were too low to be ignored. Compared to those of polar compounds in DCM extracts, the relative abundance of neutral nitrogen compounds (N1 and N1O1 classes) in the MDC extracts decreased significantly. In contrast, the acidic compounds (O2, O3, and O4 classes) all showed an obvious increase in the MDC extracts compared to the DCM extracts. It was notable that most of the polar compounds in MDC extracts were O2 and O3 compounds with double bond equivalent (DBE) values = 1 from the perspective of DBE distribution. The proportion of these two compound classes was much higher than that of all other polar compounds. Therefore, we believe that these two compound classes are the decisive factors for changing sandstone wettability combined with previous studies. In addition, based on the number of oxygen atoms and DBE values, we inferred that the O2 (DBE = 1) class was the long-chain saturated fatty acids and that the O3 (DBE = 1) class was the hydroxyl acids containing both one carboxyl and one hydroxyl group. Furthermore, the final determination of the wettability degree of the sandstone surface was the amount of all polar compounds, not only the relative abundance of these two types of acids. These two types of acids in crude oil were equivalent to anchor molecules on the surface of sandstone, and other polar compounds were adsorbed onto their surface to make the sandstone preferentially oil-wet.

Water-in-oil emulsion stability and demulsification via surface-active compounds: A review

This paper aimed to review the research on emulsion formation, stability, chemical demulsification, and hydrophilic–lipophilic balance in chemical studies and other aspects related to emulsion thermodynamics. The global increase in energy demand pressures oil and gas producers to develop and explore a new source of energy. Crude oil is one of the indispensable sources produced from unconventional and conventional resources. It is accompanied by high water content during production activities, and this water is complex and has a high content of contaminants. This water is also produced in the form of foam or emulsion. Water-in-oil emulsion is considered as a common type in petroleum industry. Oil emulsion is very harmful due to the associated difficulties during the refining and transportation of crude oil and the limitation in the produced water discharge. The emulsion in petroleum industry is stable due to the natural surface-active compounds in crude oil. Thus, oilfield researchers need to study different utilization methods to demulsify emulsion. Chemical method is considered as an essential method in treating petroleum emulsion by using demulsifiers, such as non-ionic surfactant.

Modeling of nitrogen solubility in unsaturated, cyclic, and aromatic hydrocarbons: Deep learning methods and SAFT equation of state

BackgroundAn accurate understanding of the nitrogen solubility in hydrocarbons is crucial for developing enhanced oil recovery (EOR) by nitrogen injection and the design of thermal separation and chemical conversion processes in chemical industries and oil refineries. Unsaturated, cyclic, and aromatic hydrocarbons as important compounds of crude oil are common solvents in the chemical industry that have received less attention compared to normal alkanes. MethodsIn this paper, four deep learning models, including recurrent neural network (RNN), long short-term memory (LSTM), deep belief network (DBN), and convolutional neural network (CNN) were developed for estimating the nitrogen solubility in unsaturated, cyclic, and aromatic hydrocarbons. To this end, 673 experimental nitrogen solubility data for 23 various hydrocarbons were collected from the literature in a wide ranges of operating pressure (0.03–100.1 MPa) and temperature (78–662.8 K). The input parameters to the models were considered critical temperature, critical pressure, and molecular weight of hydrocarbon solvents accompanying operating conditions of temperature and pressure. Also, the performance of deep learning models was compared with Soave-Redlich-Kwong (SRK), Peng-Robinson (PR), and statistical associating fluid theory (SAFT) equations of state (EOSs). Significant findingsThe CNN model is able to estimate the experimental values of nitrogen solubility with a root mean square error (RMSE) of 0.0211. Also, SAFT EOS outperformed the two cubic EOSs. Based on sensitivity analysis, pressure has the greatest impact on nitrogen solubility in unsaturated, cyclic, and aromatic hydrocarbons, followed by temperature and the critical temperature of hydrocarbons. Nitrogen solubility in unsaturated, cyclic, and aromatic hydrocarbons increases with the increase in pressure and temperature, and it lowers by the increase in the critical pressure, critical temperature, and molecular weight of hydrocarbon solvents. Finally, high reliability of the experimental data and statistically high validity of the CNN model were proved by the Leverage approach. The findings of this study can have implications in increasing the efficiency of gas processing units, thermal separation, and chemical conversion processes.

Pechini Sol-Gel Synthesis and Characterization of NiWO4/W5O14/WO3 Nanocomposite for Photocatalytic Desulfurization of Thiophene

One of the most important problems in the oil industry is the presence of sulfur and sulfur compounds in crude oil. Sulfur compounds in crude oil can have detrimental effects on the environment, equipment, catalysts, and end products. One of the most important goals of researchers in recent years is to sweeten petroleum products from these compounds. This study aims to use NiWO4/W5O14/WO3 composite nanostructure to solve this problem using the photocatalytic oxidative desulfurization method. This composite nanostructure has been synthesized by Pechini sol-gel method with high purity at low temperature and examined by XRD, EDS, FESEM, and FT-IR analysis. Due to the presence of WO3 in the composition, the bandgap was greatly reduced and the efficiency was increased. As a result, the nanostructure could degrade more than 73% of the sulfur in thiophene in 180 min under visible light. By optimizing the amount of photocatalyst and irradiation time, the efficiency can be improved.