Petroleum Fractions Research Articles

Kinematic Viscosity Prediction Guide: Reviewing and Evaluating Empirical Models for Diesel Fractions, and Biodiesel–Diesel Blends According to the Temperature and Feedstock

Experimental analysis of viscosity can be a straightforward and inexpensive analysis for few samples. However, in industrial processes that have high demands of properties measurements, the determination of viscosity and other properties involves time-consuming with sampling, analysis, and availability of results. Also in refineries, the sampling routines for experimental determination of the viscosity of streams are not enough to represent variations that occur in the process, such as the shift of an oil tank in distillation units. In addition, besides requiring cost of operating personnel and laboratory analyst, all of these steps can take up to one shift until the result is available. Therefore, as an alternative, the use of predictive methods of kinematic viscosity are essential. Empirical methods have been used in simulations and design calculations of streams and mixture at industries regarding kinematic viscosity (KV) of petroleum fractions and fuels at different temperatures. However, there are uncertainties about the most accurate method to use at specific condition (temperature, feedstock, volume fraction) which might affect the KV prediction of fuels with unknown composition. Therefore, we assembled and evaluated several methods to predict KV of different diesel systems. In addition, new methods for predicting KV of diesel fractions at several temperatures were also developed for improving the estimation accuracy. As a result, we developed a guide with suggestions of the most accurate models to be applied for diesel fraction from assays, diesel fractions S500 from blend system at several temperatures, and biodiesel–diesel blends at different temperatures, volume fractions, and feedstock.

Fractionation, Chemical Analysis, and In Vitro Testing Identify Bioactive Components in MC252 Crude Oil

Abstract Crude oil is a complex mixture that includes polycyclic aromatic hydrocarbons (PAHs) as one of its major components. The toxicity of some chemically substituted PAHs found in oil, such as the methylated species, are relatively understudied. A combination of chemical fractionation and analysis coupled with a bioassay was used to identify a subset of oil PAHs that activated aryl hydrocarbon receptor (AHR). Silica gel chromatography was used for primary and secondary oil fractionation, and standard and reverse phase high performance liquid chromatography (HPLC) were used for the final fractionation steps. Both gas chromatography (GC-) and HPLC-coupled with mass spectrometry (MS) were used to separate and identify compounds present in the petroleum fractions. Bioactivity of the individual fractions was identified and measured using a recombinant yeast strain that expressed the human aryl hydrocarbon receptor complex (AHRC) transcription factor that is composed of human AHR and the ARNT proteins. AHRC activation by oil components results in expression of β-galactosidase, and readout from this enzymatic activity is proportional to the amount and potency of the compounds that activated the system. Silica gel separations produced 25–29 fractions that were assessed for bioactivity using the AHRC reporter system. Bioactivity peaked with the fractions that contained larger PAHs that included four ring compounds such as the triphenylenes, benzanthracenes, and chrysenes (MW 228 + additional methyl groups). When tested as individual compounds, the triphenylenes and benzanthracenes were less potent than the chrysenes, so the latter constituted more of the AHRC signaling activity in the oil fractions. The chrysenes in bioactive fractions were mixtures of the parent compound along with mono-, di-, tri-, and tetra-methyl derivatives and other PAHs. The six possible mono-methylchrysenes were obtained and tested for AHRC activity and for their concentrations in oil. Chrysene, 1-, 2-, 3-, and 6-methylchrysene were present, but 4- and 5-methylchrysene were not detected in the bioactive fractions of oil that were resolved by HPLC. When tested individually in the AHRC bioassay, 4-methylchrysene was the most potent ligand, and 5-methylchrysene was the least potent. Synthetic mixtures of PAHs were reconstructed based upon the chemical composition of one fraction with the high AHRC activity. Collectively, these data show that: 1) the six methylchrysene isomers are within an order of magnitude of chrysene in their ability to activate the AHRC bioassay; 2) although they are a minor group, the chrysene compounds in oil potently activate AHRC signaling; 3) chrysenes diminish as oil weathers, while triphenylenes of identical molecular weight persist, 4) this methodology can be useful for identification and characterization of the bioactivity of sub-fractions and individual compounds found in oil.

Occurrence and exposure risk of mono-aromatic hydrocarbons in selected petroleum product jetty impacted soils from the Niger Delta, Nigeria

This study evaluated the occurrence and human exposure risk of mono-aromatic hydrocarbons (MAHs) such as benzene, toluene, ethylbenzene, and o,p-xylene (BTEX) in soils from petroleum product jetty from the Niger Delta, Nigeria. Samples were collected from the top (0-15 cm), sub (15-30 cm), and bottom (30-45 cm) soil depths. The MAHs components were determined using Headspace gas chromatography-mass spectrometer (HS-GCMS). The individual and ƩMAHs concentrations ranged from not detected (ND) to 1528 µg kg-1 and ND to 2512 µg kg-1 respectively. The total cancer risks were within the low category. The source identification indicated that the origin MAHs species are attributed to solvent, paints, and gasoline-diesel spill and particulate emission from gasoline/diesel combustion exhaust in the vicinity of the petroleum product jetty. This depicts the presence of low molecular weight petroleum fractions such as gasoline and kerosene that could exhibit toxicological and carcinogenic effects to organisms in soils within the jetty. Clean-up actions should be carried out to prevent the accumulation of MAHs in soil-plant uptake and the potential ecological and human exposure risks of MAHs in the surrounding soil and aquatic ecosystem

An integrated geochemical, spectroscopic, and petrographic approach to examining the producibility of hydrocarbons from liquids-rich unconventional formations

The geochemical and petrophysical complexity of source-rock reservoirs in liquids-rich unconventional (LRU) plays necessitates the implementation of a more expansive analytical protocol for initial play assessment. In this study, original samples from selected source-rock reservoirs in the USA and the UK were analyzed by 22 MHz nuclear magnetic resonance (HF-NMR) T1-T2 mapping, followed by hydrous pyrolysis, and a modified Rock-Eval pyrolysis method (multi-heating step method-MHS). The above methods were complemented by organic petrography under reflected white and UV light excitation of the original and pyrolyzed samples. The analytical protocol presented attempts to better qualify and quantify different petroleum fractions (mobile, heavy hydrocarbons, viscous, solid bitumen), thus provide valuable and refined information about producibility of target intervals during appraisal. Results show how the hydrocarbon fractions interpreted from peak locations and intensities on NMR T1-T2 maps are in good agreement with those from MHS pyrolysis in terms of hydrocarbon mobility/producibility. Results from HP (Hydrous Pyrolysis) experiments show that an exception to this general agreement between NMR and MHS estimates occurs for the Kimmeridge Blackstone Clay samples, where MHS shows an increase of >90% in producible hydrocarbon yields vs. minimal to no presence of mobile hydrocarbons in NMR T1-T2 maps. This study clarifies the role of pore structure and networks in these discrepancies of producible oil estimates when comparing programmed pyrolysis to NMR-based techniques. This novel, multi-step and multidisciplinary approach provides a more advanced screening protocol for identifying zones of higher oil-in-place (OIP) and predicting fluid mobility prior to drilling or completions.

Monitoring of Remaining Thiophenic Compounds in Liquid Fuel Desulphurization Studies Using a Fast HPLC-UV Method

Thiophenic compounds constitute a class of sulfur compounds derived by thiophene, containing at least one thiophenic ring. Their presence in fuels (crude oil, etc.) is important and can reach 3% m/m. The combustion of fuels leads to the formation of sulfur oxides a severe source of environmental pollution issues, such as acid rain with adverse effects both to humans and to the environment. To reduce such problems, the EU and other regulatory agencies worldwide set increasingly stringent regulations for sulfur content in fuels resulting in the necessity for intense desulphurization processes. However, most of these processes are inefficient in the total removal of sulfur compounds. Therefore, thiophenic compounds such as benzothiophenes and dibenzothiophenes are still present in heavier fractions of petroleum, therefore, their determination is of great importance. Until now, all HPLC methods applied in similar studies use gradient elution programs that may last more than 25 min with no validation results provided. To fill this gap, the aim of the present study was to develop and validate a simple and fast HPLC-UV method in order to be used as a useful monitoring tool in the evaluation studies of novel desulfurization technologies by means of simultaneous determination of dibenzothiophene (DBT) and 4,6-dimethyl-dibenzothiophene and dibenzothiophene sulfone in the desulfurization effluents.

Prototyping of co-composting as a cost-effective treatment option for full-scale on-site remediation at a decommissioned refinery

The costs for managing process wastes and their environmental and social impacts is contributing to the poor economics of petroleum hydrocarbon refining. The hypothesis tested was that oily sludge co-composted at a pilot scale would enable a proof of concept (prototype) for remediation at commercial field scale. The aims of the study were to translate pilot-scale outcomes to commercial terms for full scale treatment, as well as studying leachability of the contaminants, and biodegradation of the petroleum fractions. A co-composting experiment, based on a relatively simple windrow design with readily available organic amendments, demonstrated the potential to cost effectively remediate oil-contaminated soil and sludge on-site at a petroleum refinery. An initial mesophilic - thermophilic phase, characterised by high windrow temperatures (up to 60–65 °C), incorporating weekly windrow turning, resulted in fast rates of removal of total petroleum hydrocarbons (TPH) (>3000 mg kg−1. day−1) and polycyclic aromatic hydrocarbons (PAHs) (9 mg kg−1. day−1) over the first month. The remaining period of the biphasic degradation process was passive i.e. without windrow turning. At the end of the experiment, TPH in the composted windrows of organic amended sludge were decreased from 62% (w/w) (in air dried sludge), the highest reported in the oil composting literature, to 1% in the final mix, meeting the targeted solid waste disposal criteria of 1% TPH. PAHs were reduced by 96% to below relevant solid waste and contaminated soil health investigation levels (HILs) to considerably less than 100 mg kg−1. The major conclusion was that the study enabled costings for commercial scale-up to be developed indicating on-site treatment could be achieved at approximately $AUD 150 compared to off-site treatment at $AUD 1250 per tonne.

Development of a generalized model for predicting the composition of homologous groups derived from molecular type analyses to characterize petroleum fractions

Two best-known molecular type analyses are PNA and SAP methods, which divide an olefin-free fraction into the sub-fractions (Paraffins, Naphthenes, and Aromatics) and (Saturates, Aromatics, and Poly-nuclear aromatics), respectively. In this study, a new generalized model has been put forward for predicting both PNA and SAP content of petroleum fractions in terms of their measurable bulk properties. The model receives the normal boiling point ( T b ), specific gravity ( S G ) and refractive index ( R I ) as input parameters to predict PNA and SAP compositions of petroleum fractions. Furthermore, two auxiliary relations are developed for the estimation of the refractive index (based on S G and T b ) and normal boiling point (based on M w and S G ), to be used in situations that some of the input data are unavailable. Auxiliary correlations will be able to enhance the model flexibility so that it can predict the PNA or SAP composition of petroleum fractions, applying either the pair inputs ( T b , S G ) or ( M w , S G ). The model validation was entirely checked against a wide range of experimental data available in the literature, and good conformity was observed. The mean of AADs in the prediction of both PNA and SAP compositions of 156 light and heavy petroleum cuts revealed the value of 2.5% for the proposed model. A careful comparison was also performed between the proposed model and other existing well-known methods. The evaluation of results showed an AAD of 7.8% for the Riazi-Daubert method and an AAD of 9.5% for the Van Nes and Van Westen method. Moreover, sensitivity analysis of the model outputs was carefully surveyed with respect to its input parameters. It was viewed that the model outputs were less affected by probable errors that occurred in input parameters rather than the other methods. Given that the proposed model converts each petroleum cut to a well-defined ternary mixture of PNA or SAP sub-fractions, it can significantly be efficient in the characterization of reservoir fluids. Based on this, a comprehensive evaluation was conducted to verify the proposed model influences on predicting bubble pressures of 20 oil samples and simulating the differential liberation test for three oil samples. The outcome of the evaluations indicated that the proposed model could effectively improve the oil characterization process. • The two best-known molecular type analysis methods (PNA and SAP) were applied to characterize the ambiguous nature of petroleum fractions. • A new generalized model was developed for predicting the PNA or SAP composition of petroleum fractions in terms of their measurable bulk properties ( T b , S G ). • A careful comparison was also performed between the proposed model and other existing well-known methods. • The proposed model applications were investigated in predicting the bubble pressures of 20 oil samples and simulating differential liberation tests for three oil samples. • The results showed that the proposed model has superior abilities in comparison with the previous methods and could effectively improve the oil characterization process.

Concentrations, origin, and human health risk of polycyclic aromatic hydrocarbons in anthropogenic impacted soils of the Niger Delta, Nigeria

The background occurrence, sources, and human health risk of 16-USEPA priority polycyclic aromatic hydrocarbons (16-PAHs) in soils from anthropogenic environments of the Niger Delta, Nigeria were investigated. After extraction with dichloromethane/n-hexane by ultrasonication and clean-up in silica gel/alumina packed column, gas chromatography-mass spectrometer (GC-MS) was used for the determination of the 16-PAHs concentration. The mean total concentration of the 16-PAHs ranged from 115 to 3920 µg/kg. The mean concentrations of the total ∑16 PAHs followed the order deep soil > top soil > bottom soil > sub soil. The ring-PAHs distribution showed an irregular trend in the soil profiles, and the average compositional pattern of the ring-PAHs is in the order of 5-ring > 4-ring > 3-ring > 2-ring > 6-ring. Depending on the exposure concentrations and duration, the total cancer risk for adults and infants may increase the health risks to workers and inhabitants. The principal sources of PAHs were attributed to anthropogenic activities associated with traffic and non-traffic emissions and spills from petroleum fractions, solvents, and crankcase oil in the solid waste, abattoir, fuel station, plastic scrap, and auto-mechanic sites.

Estimating the asphaltene critical nanoaggregation concentration region using ultrasonic measurements and Bayesian inference

Bayesian inference and ultrasonic velocity have been used to estimate the self-association concentration of the asphaltenes in toluene using a changepoint regression model. The estimated values agree with the literature information and indicate that a lower abundance of the longer side-chains can cause an earlier onset of asphaltene self-association. Asphaltenes constitute the heaviest and most complicated fraction of crude petroleum and include a surface-active sub-fraction. When present above a critical concentration in pure solvent, asphaltene “monomers” self-associate and form nanoaggregates. Asphaltene nanoaggregates are thought to play a significant role during the remediation of petroleum spills and seeps. When mixed with water, petroleum becomes expensive to remove from the water column by conventional methods. The main reason of this difficulty is the presence of highly surface-active asphaltenes in petroleum. The nanoaggregates are thought to surround the water droplets, making the water-in-oil emulsions extremely stable. Due to their molecular complexity, modelling the self-association of the asphaltenes can be a very computationally-intensive task and has mostly been approached by molecular dynamic simulations. Our approach allows the use of literature and experimental data to estimate the nanoaggregation and its credible intervals. It has a low computational cost and can also be used for other analytical/experimental methods probing a changepoint in the molecular association behaviour.

Models for BTEX evaluation in cases of oil spill on the sea, using Experimental Desing

The objective of this study was to evaluate and obtain mathematical models, using the experimental design methodology, capable of predicting the contamination of benzene, toluene, ethylbenzene and xylenes (BTEX) in cases of oil spillage at sea, and to evaluate the acute toxicity of the soluble petroleum fraction (FSA). The factorial experimental planning was developed to describe the concentration of each compound according to the variables: oil °API, contact time oil/seawater after spillage and ambient temperature. The models presented can be used to quantitatively predict BTEX contamination in seawater with accuracy greater than 99%, within the studied ranges. The contact time oil seawater was the most determining factor in the concentration/contamination of BTEX in the Petroleum FSA. According to CL50% the soluble fraction of oil of °API 39.8 showed higher toxicity, with a LC50% of 46.07 with 1 h, and 11.38 with 96 hours of contact time oil/seawater, while the oil °API 32.8 showed lower toxicity, however presented higher concentrations of BTEX in FSA, this is possibly due to the synergistic effect of other hydrocarbons that became bioavailable to Mysidopsis juniae during the tests. The samples demonstrated potential environmental risk in cases of oil spillage, and these results can help in the development of a risk assessment of oil spills and serve as a useful analytical tool for emergencies.

Comprehensive Composition, Structure, and Size Characterization for Thiophene Compounds in Petroleum Using Ultrahigh-Resolution Mass Spectrometry and Trapped Ion Mobility Spectrometry.

Thiophene compounds are the main concern of petroleum desulfurization, and their chemical composition and molecular configuration have critical impacts on thermodynamic and kinetic processes. In this work, atmospheric pressure chemical ionization (APCI) was employed for effective ionization of thiophene compounds in petroleum with complex matrix, in which carbon disulfide was used for generating predominant [M]+• ions without the need of derivatization as for electrospray ionization. APCI coupled with ultrahigh-resolution mass spectrometry (UHRMS) was successfully applied to the composition characterization of thiophene compounds in both a low boiling petroleum fraction and a whole crude oil. APCI coupled with trapped ion mobility spectrometry (TIMS) was developed to determine the shape and size of thiophene compounds, providing configuration information that affects the steric hindrance and diffusion behavior of reactants in the desulfurization reaction, which has not been previously reported. Moreover, the comprehensive experimental structural data, expressed as the collision cross section (CCS) of the ions as surrogates of molecules, provided clues to the factors affecting the desulfurization reactivity of thiophene compounds. Further exploration showed that not only qualitative analysis of thiophene compounds can be achieved from the correlation between m/z and CCS, but also molecular size was found to be correlated with CCS that can be used as structural analysis. Overall, the molecular composition and dimension analysis together can provide substantial information for the desulfurization activity of thiophene compounds, facilitating the desulfurization process studies and catalyst design.

Molecular Reconstruction of Hydrocarbons and Sulfur-Containing Compounds in Atmospheric and Vacuum Gas Oils

The inherent complexity of petroleum fractions makes molecular reconstruction an essential element to make use of advanced kinetic models in the petrochemical industry, in particular when sulfur co...

Prediction of the Viscosity of Liquid Petroleum Products

The article deals with the new technique for predicting the viscosity of liquid petroleum products, which differ significantly in physicochemical properties and fractional composition, in a wide range of state parameters. No specific information is used to predict viscosity other than molar mass, average volume boiling point, and relative density at 20 °C. It is shown that the deviation of the predicted values from the experimental data is comparable to the error of the viscosity measurement. Methods for correcting the calculation results using limited experimental information are proposed. The application of the developed method is advisable in conditions of a lack of empirical information about the petroleum products viscosity. Keywords: viscosity prediction; petroleum products; petroleum fractions.

Improvement on the Production Energy of Shale oil Using Waste Plastics

An alternative fuels is obtained by co-pyrolysis of waste plastics and oil shale as well as contribute to the search of technologies that reduce the negative environmental impact of waste. Shale oil and waste plastic are unconventional sources of energy. The two materials are significant to Nigeria’s economic sustainability but yet to be exploited efficiently. The aim of this work is to reduce the energy needed to obtain shale oil via kinetic parameters by the thermal decomposition of Lokpanta oil shale mixed with plastics. The kinetics of the thermal decomposition of Lokpanta oil shale/ polyethylene blend was determined using data provided by thermo-gravimetric analysis done at 28°C to 887.44°C with heating rate of 10°C/min and a nitrogen flow rate of 60ml/min. The decomposition of the co-pyrolysis of the mixture of Lokpanta oil shale and the polyethylene was recognized in three stages, of which the first stage was between 28 and 316.41°C which corresponded to the loss of water from the sample. The second stage was between 316.41°C and 481.47°C, which depicted an overlap of the organic matter (kerogen) and the degradation of polyethylene. The final stage was between 481.47°C and 887.44°C, and it exposed the decomposition of the mineral matter of the oil shale. The Kinetic parameter was determined using non-isothermal methods of degradation. Hence the presence of the plastic acted as catalyst in the decomposition of the organic matter of the shale which consequently lowered the activation energy required to obtain shale oil with relevant application as aliphatic fractions of petroleum.

CFD investigation of fouling mechanisms in the crude oil preheat network

Fouling phenomena, generally related to heavy crude oils and bituminous petroleum fractions, nevertheless affects significantly the preheat train (PHT) of the light Algerian crude oil. In this study, a two dimensional model was developed using the computational fluid dynamic (CFD) method in order to investigate fouling behavior in the PHT of Algiers refinery. A fouling model was proposed specifically for the studied crude oil. The model includes a pseudo detailed chemical kinetic mechanism and it considers the deposition of inorganic matters. The proposed model was validated using the experimental results from literature. The simulation results show good agreements with the experimental data. The deposition mechanism of the two fouling routes was studied by analyzing the effect of flow velocity on the thermo-hydraulic conditions of near wall regions. The results indicate that the chemical reaction fouling is controlled by kinetic reaction process and the deposition of inorganic species is dominated by mass diffusion. The distribution of the initial fouling rate was evaluated along the entire heat exchangers network. The simulation results show that the inorganic process was predominant at the first heat exchanger and the chemical reaction fouling reaches its maximum at the PHT outlet.

Micellar solubilization of petroleum fractions by heavy alkylbenzene sulfonate surfactant

The primary mechanism of surfactant enhanced oil recovery (EOR) has always been ascribed to ultralow interfacial tension (IFT) between oil and dispalcing fluid by forming middle-phase microemulsion. However, it is found in field trials that oil can be largely produced by low concentration surfactant flooding without producing microemulsion. Herein, a widely used EOR surfactant, heavy alkylbenzene sulfonate (HABS) was selected to investigate its micellar solubilization behavior for petroleum fractions, alkanes and aromatics, by using UV–Vis spectroscopy, dynamic light scattering, transmission electron microscopy, small-angle neutron scattering (SANS) and fluorescent microscope. Increasing the surfactant concentration resulted in increase of solubilization capacity, and the micellar size increases with the addition of additives, accompanied by an appearance transition from transparent to opaque before and after the maximum solubilization capacity. Alkanes is situated in the micellar core, while aromatics resides in the palisade layer. The evolution from micelle to emulsion has been proved to be a disperse phase mutations once the maximum solubilization capacity is reached. These findings provide support for the contribution of micellar solubilization to surfactant EOR process.

A predictive method for constructing the distillation curve of petroleum fluids using their physical bulk properties

A new predictive method is presented to construct the distillation curve of different petroleum fractions. The proposed model is capable of predicting both types of distillation data (ASTM D86 and TBP) for the whole range of volume fraction distilled from the initial boiling point (IBP) up to the final boiling point (FBP). To the best of our knowledge, no predictive model has been proposed so far to forecast the distillation curve of petroleum fractions using their physical properties (e.g. specific gravity, molecular weight). Four characteristic parameters are introduced in the proposed model that must be determined for any arbitrary petroleum fluid, exclusively. Using a mathematical base, a system of nonlinear equations is developed including four independent equations and four unknown variables. In fact, the exact solution of the system of equations determines the model's characteristic parameters (α, β, c, Sf). Unlike the previously existing methods, no experimental distillation data are needed to determine the model parameters and the only input data required are the physical properties of petroleum fractions (Mw, SG,Tb). The model validity was thoroughly checked against available petroleum samples and predicted results agreed well with experimental data. A comparison was also accomplished between the proposed model abilities and the most well-known methods previously published, the results of which are presented. Moreover, a group of auxiliary relations is developed for the estimation of those input parameters that may be unavailable. The outcomes revealed that auxiliary correlations could enhance the predictability power of the proposed model in situations that required input parameters are incomplete.

Thermal and Catalytic Fast Pyrolysis of Oily Extracts of Microalgae: Production of Biokerosene

Three different microalgae species, Desmodesmus sp., Nannochloropsis oculata and Halamphora coffeaeformis were grown under controlled conditions. The resulting dry biomass was characterized by TG-DTA (thermogravimetry-differential thermal analysis) and extracted with three solvents having different polarities. The extracts gross mass yields varied from 2% using n-hexane to 23% (or 74% when subtracting the volatiles and ashes) when using methanolchloroform whatever the microalgae species. Fourier transform infrared (FTIR) spectra of all extracts suggested the presence of fatty esters and acids. The extracts were pyrolyzed at 600 °C, using a micro pyrolizer coupled to a gas chromatograph-mass spectrometer (GC-MS), without and with γ-alumina as catalyst. Hydrocarbons concentrations varied respectively from 92% in the better case to 46% in the worst case. The C9-C15 fraction of these hydrocarbons, potentially useful for biokerosene formulation, was object of detailed analysis. In this fraction, nitrogenous products had concentrations always lower than 0.1%. The main hydrocarbons produced were linear 1-alkenes for thermal pyrolysis whereas for pyrolysis with γ-alumina, linear 1-alkenes and also alkenes isomers and linear alkanes, together with cyclic and aromatic compounds were observed for all microalgae species, but in different proportions. The C9-C15 fraction of pyrolyzed extracts can be considered as precursor for biokerosene or direct “drop in” fuel for kerosene petroleum fraction.

Structural analysis of petroporphyrins from asphaltene by trapped ion mobility coupled with Fourier transform ion cyclotron resonance mass spectrometry.

Molecular characterization of compounds present in highly complex mixtures such as petroleum is proving to be one of the main analytical challenges. Heavy fractions, such as asphaltenes, exhibit immense molecular and isomeric complexity. Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with its unequalled resolving power, mass accuracy and dynamic range can address the isobaric complexity. Nevertheless, isomers remain largely inaccessible. Therefore, another dimension of separation is required. Recently, ion mobility mass spectrometry has revealed great potential for isomer description. In this study, the combination of trapped ion mobility and Fourier transform ion cyclotron resonance mass spectrometry (TIMS-FTICR) is used to obtain information on the structural features and isomeric diversity of vanadium petroporphyrins present in heavy petroleum fractions. The ion mobility spectra provided information on the isomeric diversity of the different classes of porphyrins. The determination of the collision cross section (CCS) from the peak apex allows us to hypothesize about the structural aspects of the petroleum molecules. In addition, the ion mobility signal full width at half maximum (FWHM) was used as a measure for isomeric diversity. Finally, theoretical CCS determinations were conducted first on core structures and then on alkylated petroporphyrins taking advantage of the linear correlation between the CCS and the alkylation level. This allowed the proposal of putative structures in agreement with the experimental results. The authors believe that the presented workflow will be useful for the structural prediction of real unknowns in highly complex mixtures.

Evaluation and Characterization Parameters of Crude Oils and Petroleum Fractions

Characterization of crude oil has always been an area of interest in the refining field; However, the need to define the properties of crude oil has gained importance in the production and distribution processes, and this is done simply by measuring the properties of crude oil, as the properties of these properties change according to the geological nature in which the oil is found in the traps and thus the physical and chemical properties must be studied and defined for this type Oil or so, from these physical and chemical properties such as API° (American Petroleum Institute), specific weight, pour point, viscosity, total sulfur content, vapor pressure, distillation, initial boiling point (IBP), final boiling point (FBP), were evaluated. The hydrocarbon residue and contents of crude oils were collected from the various oil fields in the Masala, Sarir, and Al Fountain fields using standard ASTM procedures. The results of crude oils in the three oil fields were compared with each other and with other international crude oils. The standards and specifications of their petroleum products were also examined. This study was conducted on the crude oil of the obelisk, bed, and fountain in 2017 that are mixed together to feed the oil refinery in Tobruk. The standards and specifications of the mixture and petroleum products of the refinery, including light Naphtha, heavy Naphtha, Kerosene, and Diesel, were measured and compared with other types of crude oil. According to the evaluation criteria, the examined crude oils can be classified as light sweet crude oil due to the high API value and low sulfur content in it, the percentage of Diesel oil is low and the (K) factor was low. It was also found that light crude oil has a high percentage of light fracture and that the pour point of light crude oil is higher than that of heavy crude oil. The salt content was also shown to be low in the mixture compared to other types. An increase in the boiling point of the distillate was observed with an increase in the percentage of the fraction volume. Moreover, Diesel has a higher boiling point than kerosene which has a higher boiling point than naphtha for all of the combined fractions. It was also found that the water content had few effects on the crude oil.