Hydrocarbon Composition Research Articles

Comprehensive accurate prediction of critical jet fuel properties with multiple machine learning models

Quantitative structure–property relationship (QSPR) model development driven by emerging machine learning (ML) shows promise for accelerating design and preparation of jet fuels with complex hydrocarbon compositions. In this work, we collected 104 jet fuels from different refineries, determined the detailed components of the fuel composition, and tested the fuel properties (density, viscosity, net heat of combustion, freezing point and flash point) using standard methods to form a database of molecule structure/composition and properties. Subsequently, six mainstream ML algorithms were adopted to establish the QSPR models, in which the prediction accuracy of the best ML models for each property is improved to above 0.93. Finally, the best ML property models are applied to predict unseen RP-3 fuels, and all prediction errors are within acceptable limits. This effort not only provides valuable data for the construction of the jet fuel database, but also provides tools for predicting its critical properties.

Combustion Temperature and Soil Organic Horizons Composition Influence on the PAHs Content (Laboratory Experiment Results)

Fire induced changes in the content and composition of polycyclic aromatic hydrocarbons (PAHs) in organic horizons of the boreal zone soils are considered. Experiment of combustion under oxygen deficient conditions were conducted. The organic horizons of soils as peat (sphagnum oligotrophic) and two types of forests (lichen pine and green-moss spruce) were selected. The PAHs content was determined by high-performance liquid chromatography. It was found that combustion conditions, composition of organic horizons and combustibility significantly affect the content and composition of PAHs. The formation of PAHs occurs to a greater extent at 300°C. Compared with the original samples, the content increases from 2.7 to 9.7 times. Compared with the peak PAHs content (in 300°C) samples, a decrease from 5.8 to 33.0 times is found at 500°C. It is likely that the significant decrease in the content of polycyclic aromatic hydrocarbons is due to the decomposition of substances to simpler ones. The ratio of low molecular to high molecular weight PAHs is indicated. The obtained ratio greater than 1.0 can serve as an indicator of pyrogenic origin of polyarenes.

First data on concentrations and composition of polycyclic aromatic hydrocarbons in soil, bottom sediments and suspended matter of water throughout the whole Fatala River Basin (Republic of Guinea)

First data on concentrations and composition of polycyclic aromatic hydrocarbons in soil, bottom sediments and suspended matter of water throughout the whole Fatala River Basin (Republic of Guinea)

Evaluation of the growth, lipid, and hydrocarbon accumulation abilities in five strains of Botryococcus braunii (races A, B, and L) (Trebouxiophyceae, Chlorophyta)

The green alga Botryococcus braunii can photosynthetically fix CO2 and accumulate abundant hydrocarbons, which has driven interest in this species as a sustainable biofuel. In this study, five strains of B. braunii (SAG 807-1, SAG 2532, SAG 30.81, SC-1, and SC-2) were identified based on the nucleotide sequence of 18S rDNA, of which SC-1 and SC-2 were isolated from the water bodies of southern China by our laboratory. Then, the effects of different media and initial nitrogen concentrations on the growth, total lipid contents, fatty acid profiles, and hydrocarbon compositions in these five strains were compared. Molecular identification revealed that B. braunii SC-1 and SC-2 belong to races B and L, respectively, while SAG 807-1, SAG 2532, and SAG 30.81 belong to race A. Compared with mBBM and mEndo media, SAG 807-1, SAG 2532, SC-1, and SC-2 grew faster in mBG-11 media. The highest total lipid content of SAG 807–1, SAG 30.81, and SC-1 reached >45 % of cell dry weight (DW), with the maximum total lipid content of SC-2 reaching 66.52 % of DW. The major fatty acid components of the five strains of B. braunii were palmitic acid (C16:0), oleic acid (C18:1), and erucic acid (C22:1). The maximum hydrocarbon content was 22.13 % DW in B. braunii SC-1, of which 1.4 % DW was squalene. Squalene is widely used as an antioxidant and as an adjuvant in vaccines.

Polyaromatic hydrocarbons of small reservoirs of the Tomsk region

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

A Rapid Analysis Method for Determination of Hydrocarbon Types in Aviation Turbine Fuel by Gas Chromatography-Mass Spectrometry.

A rapid analysis method for determination of hydrocarbon types in aviation turbine fuel was investigated in this study. A kind of reversible adsorption material packed as an unsaturated trap was used to separate saturated hydrocarbons and unsaturated hydrocarbons in the GC-MS system. No manual process or organic reagent was needed during the entire analysis process. The contents of 13 kinds of hydrocarbons, including paraffins, monocycloparaffins, dicycloparaffins, tricycloparaffins, monoolefins, cycloolefins, alkylbenzenes, CnH2n-8 aromatics, CnH2n-10 aromatics, naphthalenes, CnH2n-14 aromatics, CnH2n-16 aromatics, and CnH2n-18 aromatics were calculated by the characteristic mass fragments detected by MS with the modified matrices of ASTM D2425. The overall analysis time was less than 10 min. The precision of this test method has been conducted with 8 laboratories attended and 16 samples analyzed. The performance of this new method was demonstrated by comparing the results tested by ASTM D1319, ASTM D2425, and ASTM D6379. This rapid analysis method can provide hydrocarbon compositions of aviation turbine fuels or other liquid hydrocarbon samples within the same distillation range.

Yeast lipids as a sustainable source of nutrients in dairy products analogs

The main objective of the study was to develop a concept for the use of oleaginous Yarrowia lipolytica biomass and single-cell oil (SCO) as vegan food components. SCOs were derived from the wild-type strain KKP 379, cultured in media containing glucose, cold-pressed rapeseed oil, and cost-effective carbon sources such as molasses and post-frying rapeseed oil. Confocal microscopy analysis of the biomass and detailed analysis of the composition of fatty acids, sterols, and polycyclic aromatic hydrocarbons (PAHs) in the extracted lipids were conducted. The choice of substrates allowed to obtain SCO from post-frying rapeseed oil medium with the desired yield (3.27 g/L), composition (UFA - 93.34%), and high oxidative stability (Τmax-204.94 min, 120 °C, isothermal conditions). The content of hexane as an extraction solvent was also evaluated, which also complied with European Union requirements (0.0007 mg/kg). All SCOs from Y. lipolytica met the European Commission's requirements for marketed oils and fats for maximum levels of benzo[a)pyrene and the sum of benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene. The content of benzo[a]pyrene was in the range of 0.52–1.71 μg/kg. Finally, the oleaginous yeast biomass was subsequently applied as an enrichment additive in plant-based analogs of Camambert-type cheese, and its potential for use in fat-rich vegan food products was discussed.

Thermal (TG/DTA) and mass (GC-HRMS) analysis of waste transformer oil and its blends

ABSTRACT This study investigates the potential use of waste transformer oil (WTO) and its blends as alternative fuels for CI engines. Thermal (TG/DTA) and mass (GC-HRMS) analyses were performed on neat samples of diesel, biodiesel, WTO, and four sets of samples with different volumetric ratios of WTO, diesel, and biodiesel. TG/DTA analysis showed that the blended samples WTO20BD10D70 and WTO30D70 had a lower range of rapid disintegration temperatures (150°C), while WTO30BD20D50 exhibited the lowest temperature range for enthalpy change. The weight loss and enthalpy change of WTO and its blends were similar to those of standard diesel fuel. GC-HRMS analysis revealed that the compounds present in WTO and its blends were n-alkanes, alkenes, aromatics, alcohols, phenols, carboxylic acids, esters, and cyclic compounds, similar to those found in diesel fuel. Sample WTO20BD10D70 showed a narrow range of compounds (C8 to C27) and a similar composition of hydrocarbons to that of neat diesel, indicating its potential as an alternative fuel. Blended samples with higher carbon numbers may be harder to ignite but more stable for long-term storage, and their composition is similar to diesel fuel, suggesting their potential as eco-friendly diesel alternatives.

The Effect of the Inhibitory Composition on the Composition of Paraffin Hydrocarbons in Oil Sediments

The effect of an inhibitory composition based on an amphiphilic polymer of polyacrylate and stearic acid on the composition of paraffinic hydrocarbons in asphalt-resin-paraffin deposits (ARPD) of high-paraffin oil was studied. It is shown that with the addition of an amphiphilic polymer and a composition to oil, differences are observed in the nature of their molecular mass distribution of paraffinic hydrocarbons of the surfactants. The action of the polymer leads to a decrease in the content of hydrocarbons of the composition C16–C21 and an increase in the proportion of high-molecular hydrocarbons C22–C34. The use of stearic acid as a surfactant in the composition, on the contrary, reduces the amount of high molecular weight paraffin hydrocarbons.

Compositon of Cracking Products of Resins and Asphaltenes and their Mixture in Case of Methane Crude Oil

The influence of the duration of thermal action on the composition of cracking products of resins, asphaltenes and their mixture, isolated from methane heavy crude oil of Zyuzeevskoye oil field was studied. Cracking was performed in a closed reactor at 450°С for 60, 90 and 120 min. Data on the mass balance of the process, composition of hydrocarbons and sulfur-containing compounds in the cracking products were obtained. It was shown that the yields of coke increased with the process duration in the cracking of every studied material. The joint presence of resins and asphaltenes in a mixture changed the direction of thermal transformations of these components in the cracking process.

Soybean oil-based green diesel production via catalytic deoxygenation (CDO) technology using low-cost modified dolomite and commercial zeolite-based catalyst

Green diesel derived from sustainable biomass is an alternative and potential energy source to petroleum fossil fuel replacement in response to reducing carbon footprint and achieving a circular economy, which has sparked public interest and concern in advancing renewable energy development. Catalytic deoxygenation (CDO) is a promising method because it can process a wide variety of feedstocks and produce a diverse range of fuels. The CDO of soybean oil (SO) was executed using a modified low-cost dolomite catalyst denoted as NiO-CD catalyst and its performance has been compared with commercial zeolite heterogeneous-based catalysts such as ZSM-5, HY-zeolite and FCC. The NiO-CD catalyst exhibited exceptional deoxygenation ability, attaining an 88.6 % removal efficiency of oxygenated compounds, markedly surpassing all commercially available zeolite catalysts. The highest degree of CDO of SO via decarboxylation/decarbonylation (deCOx) reaction was achieved due to improvement in particle size, mesoporous structure and the presence of the synergistic effect of modified bi-functional acid-base properties of NiO-CaO/MgO catalyst. To investigate the effect of NiO-CD catalyst loading ranging from 1 to 7 wt%, a One Factor At a Time (OFAT) optimisation study was performed. The current study found that an optimised NiO-CD catalyst loading of 5 wt% yielded the highest green diesel (50.5 wt%) with an 88.63 % hydrocarbon composition. The influence of catalyst loading on deoxygenation activity is significant in green diesel production using NiO-CD catalyst.

Understanding the Hydrocarbon Accumulation Process in Deep–ultradeep Oil and Gas Reservoirs in Complex Structural Areas—The Qixia Formation in the Shuangyushi Structure in Northwestern Sichuan Basin, China

Deep-ultradeep oil and gas reservoirs in complex structural areas have typically undergone multistage tectonic processes that have a considerable influence on the hydrocarbon composition, isotopic composition, and other geochemical characteristics of petroleum. By assessing the charging period of hydrocarbon accumulation during a particular age we can determin these changes. We studied the characteristics of fluid inclusions developed in the dolomite reservoir in the Middle Permian Qixia Formation in the Shuangyushi structure of the northwestern Sichuan Basin using methods such as inclusion petrography, microbeam fluorescence fluorescence spectroscopy, and inclusion homogenization temperature. Furthermore, the main peak wavelength of the fluorescence spectrum, red–green ratio/chromatic parameter, Q650/500, as well as the chromatic parameter corresponding to emission flux at 535 nm (QF535) and their correlations with the homogenization temperature distribution, were used to identify the charging period of hydrocarbons in the Qixia Formation. The results show that different types of fluid inclusions were developed in the Qixia Formation. The fluorescence of hydrocarbon inclusions is mainly blue, with a small amount of yellow–green and orange–yellow. The max of orange–yellow, yellow–green, and blue fluorescence of the hydrocarbon inclusions range between 562 ∼ 579 nm, 497 ∼ 548 nm, and 447 ∼ 497 nm, respectively. The distribution of the homogenization temperatures during the same period ranges from 100 °C to 110 °C, from 120 °C to 140 °C, and from 160 °C to 170 °C, respectively. By combining the burial and thermal evolution histories of the Qixia Formation, we concluded that the Qixia Formation has experienced three stages of oil and gas charging, with the time of 204, 185 and 158 Ma. This method is of great significance to determine the date and duration of oil and gas accumulation, and provides technical support for the recovery of ultra-deep hydrocarbon accumulations in complex structural areas.

Solution of the Inverse Problem of Determining the Initial Hydrocarbons Composition in a Gas-Condensate Reservoir Using Field Data

Solution of the Inverse Problem of Determining the Initial Hydrocarbons Composition in a Gas-Condensate Reservoir Using Field Data

Foreign experience in determining the group hydrocarbon composition of petroleum feedstock and petroleum products

Determination of the group hydrocarbon composition (saturated and aromatic hydrocarbons, resins, asphaltenes) of petroleum dispersed systems is predominantly carried out using chromatographic analysis methods: liquid adsorption chromatography, high-performance liquid chromatography, thin-layer chromatography with flame ionization detection. The specificity of standard methods developed for the analysis of petroleum feedstock and petroleum products using a particular method often results in the incompatibility of results both in terms of the nomenclature of the identified hydrocarbon groups and the determined concentration values. This review provides a comparative assessment of chromatographic methods for analyzing the group hydrocarbon composition of petroleum feedstock and petroleum products, their features, advantages, and disadvantages. The main options for modifying standard methods aimed at achieving correlation between the results obtained by different analysis methods are described.

Variations in Oil Occurrence State and Properties during High-Speed Stirring Treatment of Oily Sludge.

Oily sludge (OS) has long been regarded as a hazardous waste, and improper disposal may lead to serious environmental concerns and human health risks. Despite various methods having been proposed and applied to the treatment of OS, the oil occurrence states and properties in sludge are rarely characterized, which may directly link to the selection and effectiveness of treatment methods. Here, confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD), gas chromatography (GC), and four components (SARA) analysis were utilized to characterize the changes in the oil occurrence states and compositions in OS samples before and after high-speed stirring (HSS) treatment. Our results show a substantial reduction in the oil concentration of OS after HSS treatment (from 32.98% to 1.65%), while SARA analysis reveals a similar oil composition before and after treatment, suggesting the broad applicability of HSS in removing oil and its insignificant selectivity towards various hydrocarbon components. This is further supported by the total petroleum hydrocarbon (TPH) analysis results, which show that the separated oil phase has a hydrocarbon composition similar to that of the original OS sample. The CLSM and fluorescence analysis suggest a homogeneous distribution of oil in the sludge, with relatively light components more concentrated in the pore systems between coarse mineral particles, whereas relatively heavy components tend to coexist with clay minerals. After HSS cleaning, both light and heavy components are removed to varying degrees, but light components are preferentially removed while heavy components tend to be retained in the sludge due to adsorption by clay minerals. This is consistent with TPH analysis, where a significant decrease in n-alkanes with lower carbon numbers (n-C14 to n-C20) was observed in the residual sample. Our findings demonstrate the dynamic response of oil occurrence states and compositions to the OS treatment process and highlight the importance of characterizing these fundamental properties prior to the selection of OS treatment methods.

Molecular dynamics study of shale oil adsorption and diffusion behavior in reservoir nanopores: Impact of hydrocarbon composition and surface type

Understanding shale oil adsorption in reservoir nanopores is essential for efficient extraction. This study used MD simulations to analyze the adsorption and diffusion of two- and multi-component hydrocarbons (Aromatics, Alkanes, Resin) on various shale surfaces (Calcite, Montmorillonite, Quartzite, Organic) at 353 K and 25 MPa. Hydrocarbons formed a bilayer adsorption structure comprising a high-concentration adsorption layer (L1, 0.35–0.90 g/cm3) and a low concentration weak adsorption layer (L2), with adsorption density ranked as Resin > Aromatics > Alkanes. Reservoir surfaces were classified as ionic (e.g., calcite, montmorillonite) and non-ionic (e.g., quartz, graphite), and polar hydrocarbons exhibited higher adsorption densities and energies on ionic surfaces due to combined electrostatic and van der Waals interactions, while non-ionic surfaces showed smaller adsorption differences. For multicomponent hydrocarbons, adsorption layer densities followed the order: graphite > MMT-SiO > quartz > calcite > MMT-Na, with competitive adsorption observed. The polar component exhibited a greater adsorption advantage on the calcite, MMT-SiO side and graphite surfaces due to electrostatic interactions and π-π interactions, and a lesser advantage on the MMT-Na side and quartz surfaces. Hydrocarbon diffusivity was influenced by molecular mass and polarity and ordered as Alkanes > Aromatics ≫ Resin. Polar molecules had a weaker diffusion than nonpolar molecules at similar molecular masses. Among the multicomponent hydrocarbons, the self-diffusion coefficient (Self-D) of Resin increased, while that of lighter components decreased compared to two-component systems. These findings offer strategies for improving shale oil recovery by tailoring injection fluids to reservoir types, anionic surfactants or chelating agents may be used to reduce electrostatic interactions in carbonate and clay reservoirs, while nonionic surfactants may be more effective in quartz reservoirs.

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.

Conventional agriculture affects sex communication and impacts local population size in a wild bee

Man-made agricultural stressors have been identified to compromise the reproductive dynamics of bee populations within agricultural environments. With the aid of bee hotels, we explored the influence of conventional and organic farming systems on local population size and body traits of the mason bee, Osmia bicornis, in southern Germany. We further used a chemical ecology approach and bioassays to test whether farming management influence male pre-copulatory behaviors. We observed a positive relationship between the extent of organic agriculture in the landscape and both overall brood cell production and nesting frequency. Moreover, farming systems were found to influence body traits, with bees from organic sites being smaller in size and having a different cuticular hydrocarbon composition compared with those at conventional sites. Bioassays revealed that males were more sexually attracted to freeze-killed females from conventional sites compared with those from organic sites. Intriguingly, treating females from organic fields with synthetic semiochemicals enhanced their sexual attraction to levels comparable with females from conventional sites. Our findings shed light on the intricate interplay between farming practices and the reproductive behaviors of wild mason bees, emphasizing the need for a comprehensive understanding of these dynamics for effective conservation and management strategies.

Molecular insights into CO2 enhanced hydrocarbon recovery and its sequestration in multiscale shale reservoirs

CO2 huff-n-puff (HNP) is an attractive enhanced oil recovery (EOR) technique in shale development due to its low cost, high efficiency, and environmentally friendly feature. Molecular dynamics (MD) simulations have been widely used to investigate the mechanisms of CO2 HNP process. However, the process of CO2 HNP is highly complex, involving the CO2 adsorption and transport in multiscale porous media, while considering the effect of different hydrocarbon compositions of shale oil. In this work, we developed a novel multiscale model (nano + bulk) with the modified Eagle Ford shale oil and water as the reservoir fluid. We investigated the adsorption behaviors and transport dynamics of CO2 in the CO2 HNP process. We quantitatively evaluated the CO2 swelling effect and its miscibility with hydrocarbons. Our results show the preferential adsorption to the graphene wall is pentane < CO2 < octane. CO2 can effectively desorb the light and intermediate hydrocarbons from the graphene wall. In addition, CO2 has good swelling effect and miscibility with the light and intermediate components. Due to the large molecular diameter and the strong interactions with the nanopore wall, the heavy components tend to be trapped in the nanopore after the CO2 HNP process. However, CO2 has similar swelling effect on the light and heavy components, indicating that the heavy components in the bulk pore can be effectively swelled and produced. Different from the unstable diffusion edge in the inorganic nanopores, CO2 has a stable diffusion edge in the organic nanopores. From the adsorption perspective, CO2 has favorable sequestration performance in the inorganic nanopores in shale gas reservoirs. This work provides a comprehensive understanding of the CO2 HNP process and practical implications for CO2 sequestration in shale reservoirs.

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

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