Individual Hydrocarbons Research Articles

Integrated approach to determining the identity of the pollution of adjacent territories with oil products

The methodology of arranging laboratory studies of oil-contaminated soils, soils and bottom sediments to determine the source and composition of hydrocarbon contamination is described. The complex approach to laboratory analysis of samples of oil-contaminated soils, soils and bottom sediments is proposed, which allows a highly reliable identification of the potential source of contamination and/or making conclusions about the identity of the contamination of adjacent territories. The proposed complex of analytical methods includes infrared spectrometry, gas chromatography with mass-selective detection, thin-layer chromatography with flame ionization detection and elemental analysis (C, H, N, S, O). Application of the proposed integrated approach allows highly reliable determination of the nature of oil contamination of soils, estimation of the total gross content of oil products and their hydrocarbon composition, and identification of the potential source of pollution. Possible errors in the interpretation of the results of determining the identity of contamination of territories and the importance of using an integrated approach in drawing conclusions about the source (culprit) of pollution are shown using real soil samples taken from oil-contaminated objects and adjacent territories. The importance of taking into account the losses of volatile oil products at the stage of sample preparation for soil contamination with light oil fractions is demonstrated. The use of standard methods of sample preparation (drying of the samples under study) leads to errors in assessing the level of contamination of territories with volatile hydrocarbons and in the choice of methods of remediation of contaminated territories. To minimize losses of volatile hydrocarbons (petrol and naphtha fractions) at the stage of soil sampling and transportation the use of sorbent is proposed. Addition of a sorbent to the soil contaminated with oil products can reduce losses of volatile hydrocarbons by 15 – 20% in the analyzed samples. Application of the developed complex approach makes it possible to determine the features of the individual hydrocarbon composition, group and elemental composition of petroleum products and identify hydrocarbon indicators (markers) inherent only to a certain type of petroleum product.

Efficacy of Indigenous Bacteria in the Biodegradation of Hydrocarbons Isolated from Agricultural Soils in Huamachuco, Peru.

Pollution from crude oil and its derivatives poses a serious threat to human health and ecosystems, with accidental spills causing substantial damage. Biodegradation, using microorganisms to break down these contaminants, presents a promising and cost-effective solution. Exploring and utilizing new bacterial strains from underexplored habitats could improve remediation efforts at contaminated sites. This study aimed to evaluate the hydrocarbon biodegradation capacity of bacteria isolated from agricultural soils in Huamachuco, Peru. Soil samples from Oca crops were collected and bacteria were isolated. Biodegradation assays were conducted using diesel as the sole carbon source in the Bushnell Haas Mineral medium. Molecular characterization of the 16S rRNA gene identified four strains. Diesel biodegradation assays at 1% concentration were performed under agitation conditions at 150 rpm and 30 °C, and monitored on day 10 by measuring cellular biomass (OD600), with hydrocarbons analyzed by gas chromatography. The results showed Pseudomonas protegens (PROM2) achieved the highest efficiency in removing total hydrocarbons (91.5 ± 0.7%). Additionally, Pseudomonas citri PROM3 and Acinetobacter guillouiae ClyRoM5 also demonstrated high capacity in removing several individual hydrocarbons. Indigenous bacteria from uncontaminated agricultural soils present a high potential for hydrocarbon bioremediation, offering an ecological and effective solution for soil decontamination.

Composition of gasolinefractions of Kumkol oil and improvement of theiroperational properties

The physicochemical properties of gasoline fractions of paraffinic oil from the Kumkol field have been investigated and the distinctive features of the individual hydrocarbon composition of the straight-run gasoline fraction and catalytic reforming gasoline have been established. The wide straight-run gasoline fraction (62-180°C) of Kumkol oil was subjected to preliminary hydrotreating at an industrial unit that is part of the catalytic reforming unit using S-12T and GO70 catalysts at a process temperature of 315 – 343°C, a pressure in the reactor of 21 – 27 atm, a volume feed rate of 6.4 – 9.4 h-1, with the circulation of HCG (Hydrogen-containing gas) «on the duct». Conditions under which catalytic reforming was carried out: temperature in the reaction zone – 470 ÷ 500°C, pressure – 28 kgf/cm2 , volumetric feed rate of raw materials – 1.5 h-1, gas circulation – 5.9 mol H2 / mol of raw materials. It has been established that in the process of reforming, as a result of isomerization of n-paraffins and dehydrogenation of cylanes, isoparaffin and aromatic hydrocarbons are intensively formed in the composition of reformant, and thereby the octane number of reforming gasoline is sharply increased. Gasoline obtained in the process of catalytic reforming from a narrow fraction of Kuikol oil meets the requirements for commercial, high-octane grades of motor fuel in all quality indicators. A significant synergistic effect has been established with the combined action of a two-component mixture compared to that for individual additives: a small concentration of the additive Hightech (manganese-containing) 18 mg/l and oxygen-containing AHA (ash-free high-octane additive) increases the octane number M.M. (motor method) by 3.3 points and according to R.M. (research method) by 5.3 points, and when introducing the additive Hitech 18 mg/l in a mixture with N-methylaniline, the increase in the O.N. (octane number) for M.M. was 4.4 units, and for R.M. (research method) – 6.

Physicochemical and Fungal Analysis of a Hydrocarbon-Polluted Soil at Amadi-Ama Creek of Bonny River Port Harcourt, Rivers State, Nigeria

Numerous hydrocarbon-utilizing fungal species have been implicated with the ability to utilize/degrade hydrocarbon as carbon source, which indicate their potential for environmental cleanup in hydrocarbon-contaminated sites. In this study, five (5) indigenous fungal species were isolated from a petroleum-hydrocarbon polluted soil at Amadi-ama Creek, Bonny river shoreline, Port Harcourt, Rivers State. These fungal species may have high potential to biodegrade petroleum hydrocarbon pollutants. Samples were collected randomly from the hydrocarbon impacted soil at Amadi-ama Creek, Bonny river shoreline. Sabouraud’s Dextrose Agar (SDA) and Czapek Agar were used as growth media. Samples were examined to assess the physical and chemical characteristics such as conductivity, pH, temperature, nitrate, iron, copper, zinc, chromium, phosphate, sulphate, total hydrocarbon content, total petroleum hydrocarbon, and polycyclic aromatic hydrocarbon. These parameters are known to influence the occurrence, diversity and distribution of microorganisms in an ecological niche. Soil pH showed to be acidic (6.21), result also showed that Total hydrocarbon content, Total petroleum hydrocarbon and Polycyclic aromatic hydrocarbon values were at 306.55mg/kg, 112.134mg/kg, 44.227mg/kg respectively establishing the incidence of hydrocarbon pollution. Electrical conductivity and Temperature were at 1250 Us/cm, and 29.580C respectively while Nitrate, Phosphate, Sulphate, Iron, Copper, Zinc, and Chromium values were at 1.228mg/kg, 0.751mg/kg, 20.214mg/kg, 18.431mg/kg, 0.113mg/kg, 0.121mg/kg, and 0.042mg/kg respectively. Monitoring of the soil quality established the incidence of hydrocarbon pollution as well the incidence of anthropogenic influence on the soil putting into cognizance human activities at the shoreline. Morphological identification of obtained fungal species led to their assignment into four (4) genera and five (5) species; Aspergillus niger (28%), Aspergillus flavus (22%), Cladosporium herbarum (20%), Penicillium notatum (17%), Fusarium spp (11%). The predominance of Aspergillus isolates (28% and 22%) in this study could be a pointer to their potential to utilize hydrocarbon as their sole source of nutrient. The isolation of these indigenous fungal species could serve as a baseline study on which further analysis such as hydrocarbon degradation screening test could determine their individual hydrocarbon degradation potentials and subsequent consideration as hydrocarbon degrading microbes in subsequent bioremediation study.

Determination of individual components in finished motor gasoline by dual-channel three-column gas chromatography

A method based on a dual-channel gas chromatograph equipped with three columns and three detectors was established for the determination of individual components in finished motor gasoline. The gasoline samples were separately introduced into the two injection ports of the chromatograph using two autosamplers. The components of the sample introduced into the first injection port (channel 1) were separated on a nonpolar PONA column (50 m×0.20 mm×0.5 μm) for gasoline analysis and detected by an flame ionization detector (FID). The components of the sample introduced into the second injection port (channel 2) were separated on another PONA column. Oxygenates (e.g., ethers and alcohols), other unconventional and prohibited additives that would co-elute with the hydrocarbons (e.g., methylal, dimethyl carbonate, sec-butyl acetate, and anilines), and some difficult-to-separate hydrocarbon pairs (e.g., 2,3,3-trimethylpentane and toluene) eluted from the PONA column and entered a DM-624 column (30 m×0.25 mm×1.4 μm) to achieve further separation according to the switch timetable using the Deans switch procedure and detected by an FID. The peak of 3-methylpentane, a common component in gasoline samples, also entered the DM-624 column by the Deans switch procedure for calculation purposes. The peak areas of target components on the PONA column in channel 1 were calculated using the peak areas on the DM-624 column as well as those of 3-methylpentane on both the DM-624 and PONA columns in channel 1 with a calibration factor between the two channels. The peak areas of co-eluted components were obtained by subtracting the calculated peak areas of the target components from those of the co-eluted peaks. The mass percentages of the individual components were calculated according to the normalization method using all peak areas on the PONA column in channel 1 with relative response factors. The mass percentages of the oxygenates, anilines, and individual hydrocarbons were determined, and the group-type distribution was calculated according to the carbon number. Separation and quantitation interferences between the additives and hydrocarbons were eliminated using this procedure. Twenty oxygenates and unconventional additives, each with a mass percentage of approximately 3%, were added to a real motor gasoline-92 sample and analyzed using the proposed method. The recoveries of the target components were between 90.1% and 118.2% with relative standard deviations (RSDs) between 0.2% and 5.1% (n=6). The analysis of a real ethanol-gasoline sample showed that the RSDs of contents of most components was less than 3% (n=6). Because the heart-cut of peaks using Deans switch technique requires the precise repeatability of retention times, the retention-time repeatability of components on the PONA column in channel 2 was investigated over an extended period of time after thousands of runs of real-sample analysis. The retention times of the same component in several randomly selected motor gasoline-92 samples varied from 0.01 to 0.03 min, indicating that the proper timetable for the Deans switch remained stable for two years. The precise repeatability of retention times was achieved owing to the high precision of the electric pneumatic control of the chromatograph and the stability of the column used. Real finished motor gasoline samples with different octane numbers (gasoline-92, gasoline-95, and ethanol gasoline-95) were analyzed using the developed method, and the results acquired were consistent with those of standard methods (GB/T 30519-2016, NB/SH/T 0663-2014, and SH/T 0693-2000). If some unconventional additives (such as methylal) were added to gasoline samples, the contents of these unconventional additives could also be detected, which means one run of the proposed method could provide results corresponding to three or four runs of different standard methods. The acquisition of information on the individual components of finished motor gasoline will assist in research on precise gasoline blending.

Geochemical fingerprints of Dongpu Depression crude oils in Bohai Bay Basin, northern China: Insights from biomarkers and isotopic compositions of selected alkylnaphthalenes and alkylphenanthrenes

The Dongpu Depression is a rift lake in the Bohai Bay Basin of eastern China, where abundant oil and gas resources were discovered. Previous geochemical investigations of Dongpu Depression oils have revealed a notable lack of data regarding the isotopic compositions of individual polycyclic aromatic hydrocarbons (PAHs) from the discovered Cenozoic crude oils. Using gas chromatography-mass spectrometry (GC–MS) and gas chromatography-isotope ratio mass spectrometry (GC-IRMS), a novel approach combining molecular parameters and stable carbon isotope compositions of individual PAH was applied to study the depositional environment conditions, the different source inputs, the maturation stage and to identify the potential family of five crude oils selected from Dongpu Depression.A decrease of Ga/C30H together with low Pr/Ph ratios and changes in isotopic compositions indicate that the five Dongpu Depression oils were derived from OM deposited in an anoxic saline environment with a stratified water column where mixing of saline water and freshwater occurred. The low isoprenoid, tricyclic and tetracyclic terpane ratios in combination with the δ13C values of 1,6-DMN, 1,2,5-TMN, 1,3,6,7-TeMN, 9-MP and 1-MP attest that their sources have a mixed origin with high aquatic organism (planktonic) input and a lower land plant (C3 plant) contribution. The δ13C values of phenanthrene between −30.0 ‰ and −20.0 ‰ indicate that the studied Dongpu Depression oils belong to a single family generated from the peak to the late oil generation stage (Rc-TNR-2 between 0.85 and 1.15 %). A correlation with various basins indicates that oil samples featured by δ13C values of Phen between −30.0 ‰ and −20.0 ‰ correspond to crude oils derived from mixing of aquatic and high plant contributions with different degrees of mixtures, which have not yet reached their cracking stage (Rc < 2.0 %). Crude oils from the Carboniferous and Mesozoic-Cenozoic Tarim rocks, Australian petroleum systems, Termit Basin, Bongor Basin, Fushan Depression and the studied Dongpu Depression oils belong to that group of oils. Crude oils characterized by lighter phenanthrene isotopic compositions (δ13C values of Phen < −30.0 ‰) are mainly derived from marine/aquatic input and have already entered the cracking window (Rc > 2.0 %). This group of oils is represented in this study by the Cambrian-Ordovician Tarim Basin oil samples. The research shows the importance of the aromatic isotopic compositions in petroleum system characterization and could be used as a reference for a practical exploration campaign of petroleum.

The Effect of Individual Hydrocarbons in the Composition of Diesel Fuel on the Effectiveness of Depressant Additives

The use of depressant additives is the most effective and cost-effective way to improve the low-temperature properties of diesel fuels, like the cloud point, cold filter plugging point and pour point. However, the effectiveness of depressant additives depends on the composition of the diesel fuel and the content of certain groups of hydrocarbons in it. In this work, the effect of adding individual hydrocarbons of various groups and structures on the effectiveness of depressant additives is studied. This study is carried out on model aromatic (toluene, tetralin) and n-paraffin hydrocarbons (cetane, heptadecane, heneicosane, docosane) in various concentrations. It is shown that the most negative effect on the depressant additives’ effectiveness is due to the content of the most polar aromatic hydrocarbons and light n-paraffins in the composition of diesel fuel, and the most positive effect is exerted by the content of heavy n-paraffins in small quantities. It is proposed to involve small concentrations (1–3% vol.) of heavy n-paraffin hydrocarbons (heneicosane, docosane) to increase the effectiveness of the depressant additive. It has been established that for the more effective action of the depressant, it is necessary to take into account the content and structure of individual hydrocarbons in the diesel fuel’s composition.

Development of an effective QSAR-based hazard threshold prediction model for the ecological risk assessment of aromatic hydrocarbon compounds.

The insufficient hazard thresholds of specific individual aromatic hydrocarbon compounds (AHCs) with diverse structures limit their ecological risk assessment. Thus, herein, quantitative structure-activity relationship (QSAR) models for estimating the hazard threshold of AHCs were developed based on the hazardous concentration for 5% of species (HC5) determined using the optimal species sensitivity distribution models and on the molecular descriptors calculated via the PADEL software and ORCA software. Results revealed that the optimal QSAR model, which involved eight descriptors, namely, Zagreb, GATS2m, VR3_Dzs, AATSC2s, GATS2c, ATSC2i, ω, and Vm, displayed excellent performance, as reflected by an optimal goodness of fit (R2adj = 0.918), robustness (Q2LOO = 0.869), and external prediction ability (Q2F1 = 0.760, Q2F2 = 0.782, and Q2F3 = 0.774). The hazard thresholds estimated using the optimal QSAR model were approximately close to the published water quality criteria developed by different countries and regions. The quantitative structure-toxicity relationship demonstrated that the molecular descriptors associated with electrophilicity and topological and electrotopological properties were important factors that affected the risks of AHCs. A new and reliable approach to estimate the hazard threshold of ecological risk assessment for various aromatic hydrocarbon pollutants was provided in this study, which can be widely popularised to similar contaminants with diverse structures.

Geochemistry of oils and condensates from the lower Eagle Ford formation, south Texas. Part 6: Carbon isotopes

Compound specific carbon isotope analyses were performed on a well-characterized suite of unconventional oils and condensates produced from the lower Eagle Ford Formation. Thermal maturity is the major influence on the δ13C values of C3–C19 hydrocarbons. From ∼0.8 to ∼1.1 %Ro, the main stage of oil generation, the δ13C values of most measured hydrocarbons remain relatively constant: n-alkanes are ∼ −30 ‰: light aromatic hydrocarbons, cycloalkanes and isoprenoids are ∼ −29 to −28 ‰. Only the C4 to C10 methylalkanes exhibit high variance with carbon number with δ13C values ranging from ∼ −32 to −28 ‰, respectively. Hydrocarbons from samples ∼1.1 to 1.3 %Ro, the late oil generation stage, are 13C-enriched by ∼1–∼2 ‰. This is the range typically assigned to the influence of thermal maturity on oil from many conventional petroleum systems. The onset of significant oil cracking occurs at ∼1.3 %Ro and all measured hydrocarbons systematically become progressively 13C-enriched although the degree varies by compound class and carbon number. The δ13C values of individual hydrocarbons shift by as much as ∼ +9 ‰ for propane and butane to only ∼ +3 ‰ for methylcyclopentane from <1.1 to 1.7 %Ro. The 13C-enrichments observed in the Eagle Ford oils/condensates with increasing maturity are attributed to the kinetic isotope effect (KIE), whereby 12C–12C bonds cleave faster than 12C–13C bonds. No evidence for isotopic equilibrium was found. The consistency of the sums of the weighted δ13C values for C4–C7n-alkane/methylalkane isomers provides support for Mango's (2000a) theory that these hydrocarbons are generated from precursors with a common chemical structure that pass through a similar transition state.Source facies exert only a minor influence on the carbon isotopic composition of Eagle Ford oils/condensates. Small variances in the 13C values of C6+n-alkanes, cyclohexane and methylcyclohexane are consistent with oils produced east of the San Marco Arch being generated from shales with a higher influx of terrestrial high plant matter compared to the shales west of the Arch. Phase fractionation was shown to have a measurable impact on the δ13C values of the most volatile hydrocarbons in evaporated samples and on the least volatile hydrocarbon that underwent phase separation in the subsurface during production.

Обеспечение канцерогенной безопасности копченой рыбной продукции

The purpose of the study is to develop recommendations for rational smoke generation parameters that ensure the quality and environmental safety of smoked fish products. Objectives: to establish the influence of smoke generation parameters on the assessment of the carcinogenicity of smoked products; to evaluate the quality and safety of smoked products produced under optimal smoke generation parameters; to develop recommendations to ensure the quality and safety of smoked fish products. Research was carried out at the department of Management of Technical Systems at the Federal State Budgetary Educational Institution of Higher Education Dalrybvtuz (Vladivostok, Primorsky Region). The object of the study is the process of smoke generation. Analytical, physical and chemical methods, and mathematical modeling methods were used. To prepare smoke-drying smoke samples, 10 kg of alder sawdust with a moisture content of 30–35 % was prepared. Hot smoked smelt samples were obtained under optimal smoke generation conditions. The overall organoleptic index was 5. The content of individual polyaromatic hydrocarbons was: chrysene – 71 ng/kg; benz(a)anthracene – 70 ng/kg; benz(b)fluoranthene – 602 ng/kg; benz(a)pyrene – 64 ng/kg; benz(e)pyrene – 667 ng/kg; dibenz(a,c)anthracene – 57 ng/kg; dibenz(a,h)anthracene – 69 ng/kg, which corresponds to a generalized quality index of 0.99 (very good). During the study, the influence of smoke generation parameters on the assessment of the carcinogenicity of smoked fish products was established, and the dependence of the content of individual polyaromatic hydrocarbons on the excess air coefficient in the smoke generation zone was confirmed. Optimal smoke generation modes: smoke generation temperature 475 °C, excess air coefficient – 0.4. Rational smoke generation parameters: smoke generation temperature 450–500 °C, excess air coefficient – 0.3–0.6.

EFFECT OF AN ALKYL SUBSTITUTE ON HYDROCONVERSION OF INDIVIDUAL AROMATIC HYDROCARBONS ON Co/HZSM-5/SO42-–ZrO2 COMPOSITE CATALYST

A systematic study of the hydrogenation of individual aromatic hydrocarbons (benzene, toluene, xylene) and their mixtures was carried out at 1800C, H2/Ar=7, WHSV = 2h-1 and atmospheric pressure on a composite catalyst 0.4%Co/HZSM-5/SO42-(2.0%)–ZrO2. It has been established that the developed catalyst has a high hydrogenating ability with respect to aromatic hydrocarbons at low hydrogen pressures. Alkyl-substituted benzenes turned out to be more active. It was found that alkyl substituents increase the activity of hydrogenation of the benzene ring of an aromatic hydrocarbon. According to their conversion, benzene, toluene and xylene form the following sequence: benzene&lt;toluene&lt;xylene. It was found that the optimal temperature for the process of hydroconversion of aromatic hydrocarbons on a composite catalyst is 1800C. The influence of the concentration of the hydrogenating component of the catalyst – Co on the hydroconversion was also investigated. It was found that the optimal concentration of Co is 0.4wt %. It has been established that in a benzene:toluene:xylene mixture, the conversion of benzene in comparison with its separate hydroconversion increases by more than 10%. The hydroconversion of aromatic hydrocarbons is accompanied by the formation of high-octane naphthenic hydrocarbons - cyclohexane, methylcyclohexane and methylcyclopentane. The antibatic change in the yield of CH and MCP with the duration of the experiment shows that the hydrogenation of the aromatic ring is primary and the isomerization of C6H10 to MCP is secondary, i.e. MCP is the result of a sequential transformation. The absence of dimethylcyclohexane (DMCH) in the benzene:toluene:xylene mixture conversion products suggests that the benzene and xylene conversions additionally involve transalkylation

Characterization of renewable diesel, petroleum diesel and renewable diesel/biodiesel/petroleum diesel blends

The physicochemical properties of a renewable diesel (RD) and several petroleum diesel (PD)–dominant diesels were examined to assess the feasibility of identifying and quantifying the presence of RD and biodiesel from PD and their blends. Relative to all PD-dominant diesels, the RD exhibited a lower density, a higher flash point, reduced evaporation loss and a comparable viscosity and water content. The studied RD contained a limited amount of aromatics, with aliphatic hydrocarbons predominantly within the C15 to C18 range. Most individual petroleum hydrocarbons were detected in the PD-dominant diesels, whereas the most abundant hydrocarbons for the RD were alkanes in the <n-C19 carbon range. The typical chemical signature of RD includes clustered peaks within the C15 to C18 range on GC/FID chromatograms coupled with a sharp decline in the abundance of n-alkanes from ∼n-C19 and heavier. These properties are robust indicators of RD, even in RD/PD blends. However, quantifying the RD/PD blending ratios is challenging because of their overlapping chemical compositions. The quantified blending ratios for the blended biodiesel/PD are close to theoretical biodiesel ratios. Our analyses provide valuable insights into the forensic identification of RD, biodiesel, PD and their blends.

Long-term storage and quality stability of biodiesel fuels

Abstract A special nano-composition of biodiesel was created that can increase the storage capacity and quality stability of the biodiesel fuel. The group compositions of pure nano-biodiesel and its blends with mineral diesel fuel were analyzed using a Fourier Infra Red (IR) spectrometer, and the individual hydrocarbons were identified by a gas chromatograph. The group compositions and physical and chemical parameters of the nano-biodiesel fuel fully met the standards and remained stable from 2018 through 2021, proving that this type of biodiesel can be stored for more than 4 years while maintaining physical and chemical properties and quality parameters.

Rotational spectra of five cyano derivatives of fluorene.

The recent interstellar detection of individual polycyclic aromatic hydrocarbons (PAHs) in the dense molecular cloud TMC-1 brings interest in related species that could be present in this astronomical environment. These detections, that include pure PAHs and their cyano-derivative counterparts, were performed through the interplay between laboratory rotational spectroscopy experiments and radioastronomical observations. Here, we present the laboratory rotational spectroscopic study of the five cyano-derivatives of the PAH fluorene (C13H10). The samples for these five species were synthetized in the laboratory and then characterized in the gas phase using a chirped-pulse Fourier-transform microwave spectrometer operating between 2 and 12 GHz. The analysis of the rotational spectra allowed us to derive accurate molecular constants for the five isomers used to obtain frequency predictions that enable astronomical searches of these molecules in the interstellar medium.

Automation of the Formation of a Mathematical Formulation of Kinetics for Multistage Chemical Reactions and Numerical Solution to a Direct Problem

Introduction. The basis for research, analysis and mathematical optimization of any chemical process is an adequate mathematical model that takes into account the kinetics of the object. Kinetic analysis is a challenge in chemical technology, since it allows for optimizing synthesis processes and predicting their efficiency. Numerous chemical processes involve several stage reactions. For successful design and optimization, a mathematical model that describes each stage is needed. Creating such a model manually can be time-consuming and costly, since it requires processing a large amount of information. The modern level of automation makes it possible to accelerate the obtaining of a mathematical formulation of the kinetics of multistage reactions. In this case, working with data is greatly simplified, and the probability of making mistakes is reduced. The resulting mathematical model can be applied for further analysis and optimization of the process. The paper considers the industrial reaction of catalytic reforming of gasoline, which occupies an important place in the modern scheme of oil refining, since it is a source of high-octane components of commercial gasolines and individual aromatic hydrocarbons. This process is characterized by the participation of a large number (up to 300) of various hydrocarbons, a change in the number of moles, and non-isothermality in it. Mathematical modeling of such processes involves detailing the stages to the required level. The detailing of up to 173 stages is considered. In this setting, automation of the formation of a mathematical formulation of kinetics for catalytic reforming of gasoline has not been carried out before. Therefore, the presented work aimed at implementing effective numerical methods and algorithms for automating the building of a mathematical model taking into account kinetics, thermodynamics, and changes in the number of moles.Materials and Methods. The mathematical formulation of the kinetics of multistage reactions was developed on the basis of the mass action law. The kinetic parameters values were taken from literary sources. The direct kinetics problem was solved using algorithms: the Gear method, the Runge-Kutta method of the 4th order, and the scipy.odeint() method of the Python language. The automation concept was implemented using the IDEF0 methodology. The software was written in the Python programming language.Results. A new software was created to automate the process of forming a mathematical model, taking into account the kinetics, thermodynamics, and the volume of the reaction mixture. The program results were presented by the example of catalytic reforming of gasoline. The model implemented the possibility of taking into account the intermediate heating of the mixture in the reactor cascade. Numerical values of temperature changes corresponding to industrial data were obtained.Discussion and Conclusion. The results obtained through modeling chemical transformations in the cascade of gasoline catalytic reforming reactors confirmed the exothermic nature of the reaction. The developed software product provides displaying changes in the concentrations of reactants, as well as temperature variations in the reactor, and it can be used in scientific research organizations for the analysis of multistage catalytic processes. The results of the reaction kinetics modeling will be used in the subsequent optimization of the process conditions in production.

Evolution of physicochemical characteristics of soot in a single coal combustion flame

This study experimentally investigated the evolution of the nanomorphology, graphite crystals, oxidation reactivity, and functional groups of soot in a single coal combustion flame. Nascent (sample #1), young (sample #2), and mature (sample #3) soot were collected from a Shenhua single coal combustion flame. The soot samples were then tested and analyzed using high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy to determine their physicochemical characteristics. The results showed that the nascent soot was an individual particle, the mature soot was a highly agglomerated soot aggregate, and the young soot was a transitional particle. The primary particles of sample #1 comprised several randomly orientated individual polycyclic aromatic hydrocarbon (PAH) crystal sheets, whereas the primary particles of samples #2 and #3 were typical core-shell graphite structures. The sp2/sp3 content, volatile organic fraction, and oxidation rate constant of samples #1, #2, and #3 decreased, resulting in successively weakened reactivity. The infrared spectrum absorption of 2800–3000 and 1700–900 cm−1 indicated that the hydrogen in the three coal-derived soot samples was mainly aromatic rather than aliphatic. Furthermore, the proportion of solo and duo aromatic out-of-plane (OPLA) CH bending in samples #1, #2, and #3 increased, whereas the proportion of trio-quatro OPLA CH bending decreased.

Production efficiency and safety assessment of the solid waste-derived liquid hydrocarbons

Global fossil resource utilisation remains a concern. Organic fuels and chemicals produced through catalytic synthesis out of biomass/waste feedstock can help reduce the share of fossil resource utilisation.In this study, a solid waste-derived producer gas from the cross/updraft sliding bed gasification process was applied in a fixed bed catalytic reactor with the goal of producing rich hydrocarbon chains. The specific producer gas with CO = 10%vol., H2 = 9%vol. and CH4 = 4%vol. was applied into the catalytic reactor along with catalysts Cat-Co or Cat-CoMnK at 15 bar pressure. Both catalysts were investigated in temperature regimes of 250, 280 and 310 °C, and the liquefaction number and hydrocarbon production were determined. The liquid products were qualitatively analysed afterwards, and the safety assessment, comprising the autoignition test, was performed. The obtained results defined an optimal operating temperature close to 280 °C a value for both catalysts. The individual hydrocarbon compounds were defined mostly by alkanes and alkenes of C10–C14 hydrocarbon groups in the case of both applied catalysts. The application of MnK-promoted catalyst resulted in the production of a significant amount of C6 hydrocarbon groups as well. The results point out a wide range of compounds utilisable in many different applications throughout the production sphere and suggest the possibility of autothermal air gasification of solid recovered fuel with the goal of producing gas for catalytic synthesis with reduced operation costs. From the safety point of view, the temperature of 227.7 °C was defined as the lowest value when autoignition occurs. This lowest temperature is relevant to the Cat-Co 280 °C synthesis scenario.

FEATURES OF NATURAL GAS DEMETHANIZATION PROCESS

Today, a significant part of the raw materials used in industry consists of natural gas. Thus, an important and urgent task for the further development of the industry is the development of more advanced processes aimed at natural gas treatment and processing of. Low temperature processes in gas processing are widespread due to the increasing demand for individual hydrocarbons and the growing demand for liquefied gases. Low temperature distillation remains the most important method for separating gas mixtures, especially when high throughput is required. The demethanization process is an industrially important example of such a process, which involves the interaction of separation, cooling and heat recovery systems.This article discusses a number of basic methods for low-temperature gas separation, such as condensation, rectification, absorption and separation, as well as the features of their application. Low-temperature separation is carried out in two stages in column-type apparatuses, the first of which demethanization is carried out with methane and C2+ fractions release. An overview of the demethanization process currently used for natural gas refining is given, and the key features of the demethanizer operation are described. The technological design of the process of low-temperature distillation, the design features of the installations are considered, a typical scheme of the demethanization process is given. Various technological schemes of demethanization proposed in patents are analyzed. A comparative analysis of the use of tray and packed contact devices and criteria for choosing a mass transfer column apparatus are given. The demethanization column arrangement is shown, the internal devices of the column, the feed input system, as well as the method of supplying heat to the demethanizer are described.

Chemical and Carbon Isotope Composition Proves Effective as Gas Diagnostic Tool

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 209992, “Gas Chemical and Carbon Isotope Composition as a Diagnostic Tool for Energy,” by Zainab Almubarak, SPE, Mohammad Alrowaie, and Feng Lu, Saudi Aramco, et al. The paper has not been peer reviewed. _ Chemical and carbon isotopic compositions of produced gases are useful tools to monitor gas production and to assess their origin, thermal maturity, and migration. In the complete paper, the authors present different geochemical approaches to assess the origin of gases and thermal maturity and to evaluate the effect of adsorption on shale gas during production. Introduction Carbon isotope type curves constructed for compounds from methane through n-pentane can be used to group gases into distinct families and correlate them to their source rocks. Large variations in carbon isotope ratios exist among the natural gas compounds, which are caused by isotopic fractionation between the sedimentary organic matter (kerogen) and each individual hydrocarbon compound. During the generation of hydrocarbons from kerogen, cracking of 12C-12C bonds requires slightly less energy than 13C-12C bonds. Thus, hydrocarbons will be enriched in 12C relative to the kerogen. Methane, which contains only one carbon atom, shows the greatest fractionation and will have the most negative δ13C value (most enriched in 12C). Ethane through pentane show progressively less fractionation (less negative δ13C values), with the latter usually having a δ13C value close to that of kerogen (and associated oil). The magnitude of the fractionation effect will vary depending on the type of kerogen (i.e., Type I, II, IIS, or III), the temperature during hydrocarbon generation, and the adsorption/desorption effect. Thus, gases generated from different source rocks often have distinctive carbon isotope type curves. In shale gas (unconventional reservoirs), two different types of gases coexist—free gas and adsorbed gas. Free gas occurs in natural fractures and matrix pores, whereas adsorbed gas is noted on the surface of pores. During the early stages of production, free gas accounts for most produced gas. The adsorbed gas starts in mid-late stages but maintains high and stable production. In this study, the authors use carbon isotopic compositions of light hydrocarbons (C1–C5) to assess origin and thermal maturity and to compare different gases derived from unconventional reservoirs. Moreover, carbon isotopes are used to assess migration paths and to monitor gas production in unconventional shale gas reservoirs. The gas samples were collected periodically from the same interval to monitor any isotope variation and evaluate the effect of gas adsorption. Methods Pressurized samples of natural gas were collected from conventional and unconventional reservoirs through production tests, drillstem tests, or downhole samplers and analyzed for chemical composition. For the conventional study, a total of 13 gas samples were collected from different reservoirs (A, B, C, D, and J): four gas samples from Reservoir A, two gas samples from Reservoir B, three gas samples from Reservoir C, three gas samples from Reservoir D, and one gas sample from Reservoir J. Gases derived from Reservoirs A, B, and J are younger and shallower than gases derived from Reservoirs C and D (older and deeper). For the unconventional study, seven gas samples were collected periodically from the same shale interval (Reservoir W) from the same well (Well Y) on different dates to monitor any isotope variation.

Prediction of Refractive Index of Petroleum Fluids by Empirical Correlations and ANN

The refractive index is an important physical property that is used to estimate the structural characteristics, thermodynamic, and transport properties of petroleum fluids, and to determine the onset of asphaltene flocculation. Unfortunately, the refractive index of opaque petroleum fluids cannot be measured unless special experimental techniques or dilution is used. For that reason, empirical correlations, and metaheuristic models were developed to predict the refractive index of petroleum fluids based on density, boiling point, and SARA fraction composition. The capability of these methods to accurately predict refractive index is discussed in this research with the aim of contrasting the empirical correlations with the artificial neural network modelling approach. Three data sets consisting of specific gravity and boiling point of 254 petroleum fractions, individual hydrocarbons, and hetero-compounds (Set 1); specific gravity and molecular weight of 136 crude oils (Set 2); and specific gravity, molecular weight, and SARA composition data of 102 crude oils (Set 3) were used to test eight empirical correlations available in the literature to predict the refractive index. Additionally, three new empirical correlations and three artificial neural network (ANN) models were developed for the three data sets using computer algebra system Maple, NLPSolve with Modified Newton Iterative Method, and Matlab. For Set 1, the most accurate refractive index prediction was achieved by the ANN model, with %AAD of 0.26% followed by the new developed correlation for Set 1 with %AAD of 0.37%. The best literature empirical correlation found for Set 1 was that of Riazi and Daubert (1987), which had %AAD of 0.40%. For Set 2, the best performers were the models of ANN, and the new developed correlation of Set 2 with %AAD of refractive index prediction was 0.21%, and 0.22%, respectively. For Set 3, the ANN model exhibited %AAD of refractive index prediction of 0.156% followed by the newly developed correlation for Set 3 with %AAD of 0.163%, while the empirical correlations of Fan et al. (2002) and Chamkalani (2012) displayed %AAD of 0.584 and 0.552%, respectively.