Crude Source Research Articles

Geochemical characteristics of crude oils and source rocks in the Malaysia-Thailand Joint Development Area (MTJDA), North Malay Basin

The Malaysia-Thailand Joint Development Area (MTJDA) that located in the North Malay Basin has been investigated in this study to resolve few issues concerning to petroleum potential and resources which has been abandon for decades. Despite Malay Basin having been proven to contain prolific oil and gas resources, the MTJDA which located in the Northern area however contains mainly gas with very minor oil. Thus, this study aimed to investigate the main factor that controls the hydrocarbon generation, type and distribution in this basin. The investigation involves biomarker characterization, thermal maturity assessment of source rock, crude oil and condensate, together with oil-oil and oil-source correlation that has never been established before. The geochemical data as indicated by bitumen extraction, GC-MS and Py-GC analyses on 40 cutting samples and 8 liquid samples (six oil samples and two condensate samples) revealed that the cutting samples were moderate in quality with variable richness based on TOC (total organic carbon) and a variable degree of maturity based on the biomarker proxy parameters of isoprenoid, hopanoid and steroid. The organic matter input for the source rock was derived from a mixed marine-terrestrial and terrestrial source and deposited in fluvial-deltaic/estuarine settings having oxic to sub-oxic depositional conditions. Based on biomarker fingerprints and proxy parameters, the oil and condensate samples were essentially of the same group, originating from a similar source rock, with some facies variation due to variations in organic matter input and degree of maturity. The results also indicated that the crude oil samples were originated from the coaly and carbonaceous shales of Group I, with mixed kerogen of type II/III that could produce gas with minor oil. There is also the possibility that these hydrocarbons were generated from a deeper interval of Group E (higher thermal maturity), deposited in a similar setting as Group I.

Sustainable Liquid‐Organic‐Hydrogen‐Carrier‐Based Hydrogen‐Storage Technology Using Crude or Waste Feedstock/Hydrogen

For liquid organic hydrogen carrier (LOHC) technology to be competitive with other H2‐storage methods, it is crucial to reduce the cost of LOHC materials occupying the high proportion of the embodied energy required for system implementation. Promising approaches are to convert crude or waste feedstock into LOHC materials and to utilize crude hydrogen sources obtained from various routes. Thus, in this review, the state‐of‐the‐art advances in sustainable LOHC‐based hydrogen storage using crude or waste feedstock, associated with their conversion into LOHC materials, and coupling crude hydrogen with LOHC system to obtain high‐purity H2 without separation and purification are highlighted. Petroleum sources like light cycle oil and pyrolysis fuel oil are used after liquid–liquid extraction, combined distillation/hydroprocessing, and one‐pot hydrotreating–hydrocracking. In case of converting renewable resources (e.g., biomass and plastic waste), depolymerization followed by hydrodeoxygenation is an effective approach. To utilize crude hydrogen sources for hydrogen storage, catalysts should be designed and synthesized toward activating LOHC hydrogenation reaction at lower temperatures, along with high CO resistance. Consequently, this context provides guidance for the development of LOHC technology to accelerate its commercialization.

Effects of antioxidants on chemical and rheological properties of asphalt binders from different crude oil sources

Antioxidants can effectively mitigate or delay the oxidative aging degradation of asphalt binder, thereby improving pavement durability. While research has largely concentrated on the application of antioxidants to asphalt binders from a single source, limited studies have explored their effects on binders derived from different crude oil sources. Moreover, the relationship between the chemical and rheological properties of antioxidant-modified asphalt binders remains insufficiently understood. In this study, three antioxidants - zinc diethyldithiocarbamate (ZDC), Irganox 1010 and kraft lignin - were utilized and blended with base binders sourced from three distinct regions globally. Fourier transform infrared spectroscopy (FTIR) was utilized to analyze the impact of these antioxidants on the chemical composition of aged binders. Additionally, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were conducted to assess the high- and low-temperature performance of the antioxidant-modified binders, identifying the most effective antioxidant. The linear amplitude sweep (LAS) test further evaluated the performance of ZDC across binders from different crude oil sources. The results revealed three key findings: first, chemical functional group changes due to antioxidants are not always reflected in rheological performance; second, ZDC demonstrated superior performance across different base binders, as evidenced by improved aging indices, high-temperature rutting resistance, and enhanced fatigue and low-temperature cracking resistance; and third, asphalt binders from different crude oil sources exhibit varying sensitivities to antioxidant type and dosage. This study underscores the necessity of determining optimal antioxidant dosages for different asphalt binders, as the relationship between antioxidant dosage and effectiveness is not straightforward.

From crude oil to bitumen: Genetic variability in chemistry and its influence on viscoelastic of binders

The chemical composition and properties of bitumen are derived from crude oil, which directly influences its viscoelastic properties. Six different crude oil sources were examined to explore how crude oil characteristics impact bitumen. The bitumen was produced through in-house atmospheric decompression distillation, and aging tests were conducted on these samples. The chemical properties of the crude oils, virgin binders, and aged binders were analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Additionally, the separation and quantitative analysis of saturates, aromatics, resins, and asphaltenes (SARA) in crude oil and bitumen binders were carried out using Thin Layer Chromatography-Flame Ionization Detector (TLC-FID). Sweep tests on binders were conducted using a Dynamic Shear Rheometer (DSR). Master curves were created based on the CAM model and the 2S2P1D model to assess the dynamic viscoelastic properties of bitumen. The grey correlation method was employed to examine how bitumen chemical composition and properties affect its viscoelasticity. Results indicated that crude oil profoundly influences bitumen's chemical composition and properties. The functional group index and component content of bitumen are inherited from crude oil and are closely linked to the corresponding indices of crude oil. The functional group index, SARA, and colloidal stability coefficients of bitumen are intimately connected to the viscoelastic parameters of bitumen. The impact of the functional group index on the viscoelastic parameters is more pronounced than that of SARA content. This insight is crucial for guiding the selection of oil sources in bitumen production processes.

Investigating the potential of delignified rice husk as a carbon-rich resource for extracting glucose and its utilization in biocement production through fungal isolates.

Burning rice straw is now a significant issue faced by different regions in India, as its burning releases harmful gases, mainly carbon dioxide. Various techniques are now in trend to utilize the rice straw, e.g., producing compressed natural gas using rice straw, bioethanol, etc., as a substrate for various microorganisms. A high quantity of non-utilized rice husk generates more ideas for its proper utilization. The cellulose, hemicellulose, and lignin found in rice straws can be a fungi growth medium. In this research, the delignification of rice husk is done by acid (2% and 4% H2SO4) and alkali (2% and 4% NaOH) at 121°C at 103kPa for 1h to obtain crude carbon source which is further utilized for biomineralization. The glucose is subjected to qualitative and quantitative analysis using Molisch's and Dinitro salicylic tests. The delignification process showed a positive outcome when 2% H2SO4 is utilized maximum yield of 5.9 ug/ml free sugar concentration. Representing the highest glucose yield compared to the experiment's other acid and base substances used. Various techniques such as field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Fourier transformed infra-red (FTIR) spectroscopy are employed to examine surface and chemical alterations. The 2% H2SO4 pretreated rice husk is utilized for microbial-induced calcite precipitation using fungal isolates S1 (3), S1 (18), and S4 (1). The calcite and vaterite produced by biomineralization are confirmed using XRD for fungal isolates namely, S1 (3), S1 (18), and S4 (1) having percentage crystallinity of 59%, 46.428%, and 62.69% percentage crystallinity respectively.

Fat supplement for dairy cows during early lactation – potentials, challenges, and risks – a meta-analysis

ABSTRACT The most critical challenge in early lactation is to meet the increasing energy demand for milk production, which results in a negative energy balance (EB). The objective of this study was to evaluate the productive performance and plasma metabolite responses of early lactating dairy cows fed diets supplemented with increasing levels of different fat sources. Diets were categorized as diets supplemented with saturated fatty acid rich fat sources (SFAR), with Ca-soaps of fatty acids (CaFA), and with polyunsaturated fatty acid rich fat sources (PUFAR). There was an interaction between crude fat level and source for dry matter intake (DMI); each percentage-unit increase reduced DMI by 0.38 and 0.77 kg/d in CaFA and PUFAR, respectively, and increased DMI by 0.55 kg/d in SFAR. Corrected milk yield increased by 0.44 kg/d for each percentage-unit increase in crude fat level. Plasma non-esterified fatty acid (NEFA) concentration increased with 0.04 mmol/L per percentage-unit increase. In conclusion, the increased crude fat level increased corrected milk yield. Fat supplementation in early lactation does not seem to cause negative effects on productive performance or metabolism, and despite a small increase, both plasma NEFA and β-hydroxybutyrate (BHB) concentrations stayed below the threshold for incidence of subclinical ketosis.

Effects of Dietary Inclusion of a Crude Protein Source Exhibiting the Strongest Attractiveness to Red Sea Bream (Pagrus major) on Growth, Feed Availability, and Economic Efficiency.

Dietary incorporation of an attractive feed protein source is a practical method of enhancing feed intake and consequently improving the growth of fish. The attractiveness of 18 crude protein sources to juvenile red sea bream (Pagrus major) and the effects of the dietary inclusion of the crude protein source that exhibited the strongest attractiveness on growth, feed availability, and economic efficiency were determined. Jack mackerel meal (JMM) showed the strongest attractiveness to red sea bream among 18 crude protein ingredients. In an 8-week feeding trial, 810 juveniles were randomly distributed into 27 tanks (30 fish/tank). Nine experimental diets were prepared. The control (Con) diet included 60% fish meal (FM). Various levels (1, 3, 5, 10, 20, 40, 60, and 100%) of JMM were included at the expense of FM in the Con diet, and the resulting diets were named the JMM1, JMM3, JMM5, JMM10, JMM20, JMM40, JMM60, and JMM100 diets, respectively. Fish were hand-fed to apparent satiation twice daily for 8 weeks. The weight gain, specific growth rate, and feed consumption of red sea bream that were fed the JMM40, JMM60, and JMM100 diets were significantly (p < 0.0001 for all) higher than those of the fish fed all other diets. However, dietary JMM inclusion had no remarkable impacts on the feed utilization, biological indices, and chemical composition of the whole body of red sea bream. In terms of the economic view of the study, the economic profit index of red sea bream fed the JMM40, JMM60, and JMM100 diets was significantly (p < 0.0001) greater than that of the fish fed all other diets. In conclusion, the strongest attractiveness to red sea bream among 18 crude protein sources was observed in JMM. The inclusion of more than 40% JMM at the expense of FM in the diet of red sea bream is highly recommended for practical feed formulations to induce remarkable improvement in the growth performance of fish and the economic returns for farmers.

Optimizing bio-bitumen mixes through response surface methodology

Bio-bitumen, a sustainable alternative to petroleum-based bitumen, is gaining popularity owing to its environmental advantages and potential to address depleting crude oil sources. The purpose of this study is to use Response Surface Methodology (RSM) to optimise bio-bitumen characteristics for sustainable pavements. Bio-bitumen is produced by combining conventional bitumen with biochar, cashew nutshell liquid, waste engine oil, and phthalic anhydride. This study uses RSM to investigate how these components (biochar, cashew nutshell liquid, waste engine oil, and phthalic anhydride) influence important bio-bitumen properties (penetration, ductility, softening point, and elastic recovery). A 2^4 factorial design with 27 trials was employed to optimise the mixing procedure. Statistical analysis, employing visualizations like contour plots and surface plots revealed an optimum bio-bitumen combination having 15% biochar, 1.71% cashew nutshell liquid, 0% waste engine oil, and a phthalic anhydride concentration ranging from 4.54% to 7.5%. This study illustrates the efficacy of RSM in optimising bio-bitumen for sustainable pavements, paving the way for more environmentally friendly road construction.

Optimizing bio-bitumen mixes through response surface methodology

Bio-bitumen, a sustainable alternative to petroleum-based bitumen, is gaining popularity owing to its environmental advantages and potential to address depleting crude oil sources. The purpose of this study is to use Response Surface Methodology (RSM) to optimise bio-bitumen characteristics for sustainable pavements. Bio-bitumen is produced by combining conventional bitumen with biochar, cashew nutshell liquid, waste engine oil, and phthalic anhydride. This study uses RSM to investigate how these components (biochar, cashew nutshell liquid, waste engine oil, and phthalic anhydride) influence important bio-bitumen properties (penetration, ductility, softening point, and elastic recovery). A 2^4 factorial design with 27 trials was employed to optimise the mixing procedure. Statistical analysis, employing visualizations like contour plots and surface plots revealed an optimum bio-bitumen combination having 15% biochar, 1.71% cashew nutshell liquid, 0% waste engine oil, and a phthalic anhydride concentration ranging from 4.54% to 7.5%. This study illustrates the efficacy of RSM in optimising bio-bitumen for sustainable pavements, paving the way for more environmentally friendly road construction.

PERFORMANCE AND DIGESTIBILITY RESPONSE BY RABBITS FED DIETS CONTAINING COWPEA HAULMS (Vigna unguiculata) REPLACING RICE OFFAL AT GRADED LEVELS

An 84-day feeding trial was conducted with weaner rabbits to investigate the feeding value of cowpea haulms (Vigna unguiculata) on growth performance and nutrients digestibility. Thirtysix (36) weaner rabbits with initial live weight range of 427.33 – 474.50g were randomly allocated to six (6) dietary treatments and each treatments replicated six (6) times in a complete randomized design. Each treatment was made up of three (3) males and three (3) females with each as a replicate. The rabbits were fed diets with cowpea haulms replacing rice offal at 0%, 20%, 40%, 60%, 80%, and 100% levels according to treatments T1, T2, T3, T4, T5, and T6 respectively and T1 with 0% cowpea haulms as the control diet. The result of proximate composition and energy values of experimental diets revealed a crude protein value of 16.62% for T2 less than a similar value of 17.50% for T3, T4, T6 and T1 and T5 with a value of 18.38%. Crude fibre values ranged 12.43 to 21.00% increased across T1 –T6 as cowpea haulms (CH) level increased in the diet. Ether extract however decreased from T1 –T6 with increase in the level of CH with moisture following no particular trend. Ash was seen to decrease with increase in the diet CH, dry matter values 89.91% (T1) to 91.77% (T5) and NFE values 56.28 (T1) to 62.82 (T4) were in no particular trend. Also, ME values 3139.59 (T4) to 2731.32% (T1) did not follow a definite trend among the experimental treatments. The final weight (FW) was shown to decrease across the treatments with T1 having the highest final weight. T4 and T6 had the similar final weights. The nutrient digestibility across the six treatments revealed significant (P0.05) different. With these results from this study, it was concluded that, the bulky wastage of cowpea haulms after the seed harvest could be reduced by replacing rice offal with cowpea haulms in rabbit diets as a major crude fibre source. Cowpea haulms had no negative effects on the general growth performance of rabbits. Therefore, it is safe for farmers and feed manufacturers to include cowpea haulms to replace 100% of rice offal as a major source of crude fibre in rabbit diets.

A new ternary diagram to decipher the evolution of maturity and biodegradation of crude oil using ESI FT-ICR MS

The nitrogen-, sulfur- and oxygen-containing (NSO) compounds widely occurred in crude oil and source rock extract, which could provide useful information for maturity and the degree of biodegradation. In this paper, NSO heteroatom compounds of crude oils with a series of different levels of maturations and biodegradation were analyzed by the ESI FT-ICR MS under a negative mode, and the variations of the relative abundance of those compounds were investigated. The changes of relative content nitrogen- and oxygen-containing compounds in oils with the increasing of maturity and biodegradation degree in the ternary diagrams of DBE = 9, 12 and 15 of N1 species, DBE = 12, 15 and 18 of N1 species and DBE = 4, 5 and 6 of O1 species show similar tendency, which is restricted to solely characterizing the evolution of either maturity or biodegradation degree of crude oil. A new ternary diagram composed of N1, O1, O2 + O3 + O4 species was presented to simultaneously distinguish the evolution of maturity and biodegradation of crude oil. Data points with high maturity oil tend to shift to N1 species end-member, showing that the relative content of N1 species increases and that of O2 species decreases with increasing maturity as a consequence of decarboxylation and dehydration. Oils with high degrees of biodegradation shift to O2 + O3 + O4 species end-member, indicating that the relative content of N1 species decreases and that of O2 + O3 + O4 species increases with increasing biodegradation level which may be due to the formation of organic acids in degraded oil. Therefore, the ternary diagram with three end-numbers of N1, O1, O2 + O3 + O4 species is a useful tool to delineate the evolution of maturity as well as to estimate biodegradation degree.

Chemical and mechanical analysis of VAPro-aged asphalt binders from different crude oil sources

Asphalt binders change their properties over time under natural and anthropogenic influences since they are of organic origin. This leads to a deterioration of the mechanical behavior and, thus to higher stiffness and brittleness of the binder. This phenomenon is commonly known as “aging.” As a consequence, these changes have a negative impact on the low temperature and fatigue behavior of asphalt mix layers. The standardized RTFOT for STA and PAV for LTA are used to simulate aging in the laboratory on the bitumen scale. On the asphalt mix scale, various methods have been developed for either loose material or compacted specimens. This paper presents a recently developed conditioning method called the “Viennese Aging Procedure” (VAPro) for long-term aging of compacted HMA specimens at close-to-field conditions (T = 60°C and p ≤ 1 bar). Air enriched with traces of highly oxidizing gases (ozone and nitrogen oxides) is passed through the specimens to enhance the oxidation reaction. The chemical reactions triggered by VAPro are expected to be similar to field aging. The applicability of the method is demonstrated. Mixtures containing four binders of the same grade were aged. Significant differences in aging behavior can be observed. The VAPro-aging is about 1.2 to 2.6 times stronger than that of PAV in terms of stiffness increase on the binder level. The mechanical analysis is extended with FTIR measurements. It is shown that this method is of great use in evaluating aging behavior and detecting poorly performing binders.

A Data-Driven Rutting Depth Short-Time Prediction Model with Metaheuristic Optimization for Asphalt Pavements Based on RIOHTrack

Rutting of asphalt pavements is a crucial design criterion in various pavement design guides. A good road transportation base can provide security for the transportation of oil and gas in road transportation. This study attempts to develop a robust artificial intelligence model to estimate different asphalt pavements' rutting depth clips, temperature, and load axes as primary characteristics. The experiment data were obtained from 19 asphalt pavements with different crude oil sources on a 2.038 km long full-scale field accelerated pavement test track (RIOHTrack, Road Track Institute) in Tongzhou, Beijing. In addition, this paper also proposes to build complex networks with different pavement rutting depths through complex network methods and the Louvain algorithm for community detection. The most critical structural elements can be selected from different asphalt pavement rutting data, and similar structural elements can be found. An extreme learning machine algorithm with residual correction (RELM) is designed and optimized using an independent adaptive particle swarm algorithm. The experimental results of the proposed method are compared with several classical machine learning algorithms, with predictions of Average Root Mean Squared Error, Average Mean Absolute Error, and Average Mean Absolute Percentage Error for 19 asphalt pavements reaching 1.742, 1.363, and 1.94\% respectively. The experiments demonstrate that the RELM algorithm has an advantage over classical machine learning methods in dealing with non-linear problems in road engineering. Notably, the method ensures the adaptation of the simulated environment to different levels of abstraction through the cognitive analysis of the production environment parameters.

Origin and Geological Significance of Residual Oil in High-Angle Joint Fissures: A Case Study of the Nadu Formation in Baise Basin, South China

The Baise Basin is a Paleogene pull-apart basin with numerous strike-slip faults which are not favorable for hydrocarbon preservation. The Nadu Formation, research object of this paper, is generally rich in oil and contains a large number of high-angle joint fissures. Analyzing the origin of residual oil in high-angle joint fissures can reveal the hydrocarbon migration and accumulation characteristics of the pull-apart-type basins. Molecular geochemical composition characteristics of crude oil and oil source of the Nadu Formation were discussed based on the saturated hydrocarbon biomarker compound and stable carbon isotope distribution of n-alkanes. The studied samples were selected from four members (E2n1, E2n2, E2n3up, and E2n3low) of the Nadu Formation. The results suggested that the average oil content of E2n1 fissures is 0.32 mg/cm2, and the oil distribution is not uniform. The distribution of oil on the fissures of E2n2 and E2n3 is uniform and complete, and the oil content reaches 0.53 mg/cm2. The oil in the joint fissures of the Nadu Formation is heavy, as the light hydrocarbon is seriously lost during migration. Thus, the oil in the joint fissures is residue after crude oil loses light components during migration. By comparing the molecular biomarker characteristics and stable carbon isotopic compositions, crude oil of the Nadu Formation can be classified into three categories: E2n1, E2n2 + E2n3up, and E2n3low. The E2n1 oils have the lowest maturity and are sourced from the E2n1 source rocks. Moreover, the maturity of E2n2 and E2n3 samples are relatively high. Biomarker and carbon isotope characteristics of the E2n2 and E2n3up oils are similar, indicating that they are derived from the E2n2 + E2n3up source rocks. The E2n3low oils are the mixture of the crude oil generated from the E2n3up source rocks and the E2n3low source rocks. Results presented show that the residual oil of high-angle joint fissures in the Nadu Formation is contributed by adjacent source rocks. The crude oil discharged from the Nadu Formation can only migrate upward along high-angle joints in a short distance, and the migration distance is usually less than 5 m. In conclusion, although the Nadu Formation has developed a large number of high-angle joint fissures, crude oil in the Nadu Formation has not vertically migrated for long distance along the joint fissures. The well-preserved fractures as important shale oil storage spaces indicate that the Nadu Formation has good shale oil exploration potential. The results may provide insights into the origins of hydrocarbons in the Nadu Formation from the Baise Basin and enhanced knowledge for optimizing future exploration and production.

Distribution characteristics of Sulfur, phosphorus and trace elements in crude oil and source rock chloroform asphaltenes “a” and description of an oil-bearing system in the Ordos Basin

The multiple sets of source rocks and crude oil biomarkers in the Yanchang Formation have no clear results of oil-source correlation. Chloroform asphaltenes “A” was extracted from the source rocks and crude oils and microwave digested, and its elemental composition analyzed by ICP–MS for oil-source correlation. The S/P and the ratio of light and heavy rare earth elements are oil-source correlation indices. The total amount of transition metals may be useful for oil-oil and oil-source correlation using cluster analysis techniques, but redox parameters are not effective for oil-oil and oil-source correlation in lacustrine oil. It is proposed that the oils in the Longdong area and Jiyuan area all come from the Chang 7 source rocks. The oils in the Shanbei area are derived from the Chang 9 source rocks in the area and the Chang 7 source rocks in Longdong. The Chang 10 oils in the Shanbei area and Chang 9 oils in the middle Lake Basin appear to come from other sources. Trace elements can provide valuable clue on the hydrocarbon sources and oil migration patterns of the Yanchang Formation, which is of great significance in the search for possible deep oil-bearing systems in the Shanbei area.

Quantifying the influence of heating and resting on the bitumen microstructure

The investigation of the bitumen microstructure can provide an alternative approach to characterise the material. However, various factors prior to its analysis need to be considered, before being able to come to a meaningful conclusion. This involves the identification of factors like heating time and temperature as well as resting time and how it can affect the resulting microstructure. Furthermore, the need for quantifying the microstructure is sought after. Thus, the goal of this study is to address these parameters and quantify their respective influence via optical inverse dark- and brightfield microscopy, subsequent particle analysis of the darkfield images and partial link to infrared spectroscopy. The results show that optical microscopy in combination with particle analysis from dark field images can be used for quantification of the microstructure and even differentiate binders from different crude oil sources. However, small binder quantities, typically used for microscopy, can oxidize rapidly. Thus, a heating time of 30 – 60 s at a temperature of 150 °C was deemed sufficient for these unmodified binders. In addition to that the microstructure becomes stable after 30 min of resting, making binder characterisation via microscopy much more convenient. For imaging analysis an overall area covered by bee structure enables universal characterisation and comparison, while providing good differentiation between binder A (10%), B (2%) and C (16%). These findings should set the basis for future research, where microscopy can be used to identify and tackle important questions related to changes caused by ageing, modification with polymers, additives, filler or rejuvenators.

Spatial Distribution, Sources, Air-Soil Exchange, and Health Risks of Parent PAHs and Derivative-Alkylated PAHs in Different Functional Areas of an Oilfield Area in the Yellow River Delta, North China.

The knowledge of the spatial distribution, sources, and air-soil exchange of polycyclic aromatic compounds (PACs) in an oilfield area is essential to the development of effective control practices of PAC pollution. In this study, 48 passive air samples and 24 soil samples were collected during 2018-2019 in seven functional areas (e.g., urban, oil field, suburban, industrial, agricultural, near pump units, and background) in the Yellow River Delta (YRD) where the Shengli Oilfield is located, and 18 parent polycyclic aromatic hydrocarbons (PAHs) and five alkylated-PAHs (APAHs) were analyzed from all the air and soil samples. The ΣPAHs in the air and soil ranged from 2.26 to 135.83 ng/m3 and 33.96 to 408.94 ng/g, while the ΣAPAHs in the atmosphere and soil ranged from 0.04 to 16.31 ng/m3 and 6.39 to 211.86 ng/g, respectively. There was a downward trend of atmospheric ΣPAH concentrations with increasing the distance from the urban area, while both ΣPAH and ΣAPAH concentrations in the soil decreased with distance from the oilfield area. PMF analyses show that for atmospheric PACs, coal/biomass combustion was the main contributor in urban, suburban, and agricultural areas, while crude production and processing source contributes more in the industrial and oilfield area. For PACs in soil, densely populated areas (industrial, urban, and suburban) are more affected by traffic sources, while oilfield and near-pump unit areas are under the impact of oil spills. The fugacity fraction (ff) results indicated that the soil generally emitted low-molecular-weight PAHs and APAHs and act as a sink for high-molecular-weight PAHs. The incremental lifetime cancer risk (ILCR) of Σ(PAH+APAH) in both the air and soil, were below the threshold (≤10-6) set by the US EPA.

Use of Accelerated Natural Aging to Simulate Long-Term Asphalt Binder Aging in Pavements

Asphalt binder is prone to aging in usage conditions. Although aging an asphalt binder using a pressure aging vessel (PAV) is a popular method to simulate the long-term aging of the binder, questions have been raised about the accuracy of this method. This research is focused on (i) examining the detailed physicochemical aging processes of asphalt binders aged in a relatively natural condition, (ii) evaluating the effects of supporting medium on asphalt binder aging, (iii) comparing aging trends of binders from different crude sources, (iv) modeling and forecasting the long-term aging behaviors of asphalt binders. Seven types of neat asphalt binders were studied, and two types of supporting media were used. The natural aging condition was set to be 60°C in a dark environment, and the thickness of the asphalt film was reduced to about 0.8 mm. The longest natural aging treatment duration was 75 days. Samples were periodically taken to test their physicochemical properties. The binders were also subjected to PAV treatments for comparison purposes. It is found that most physicochemical properties of the naturally aged binders exhibit a fast change stage followed by a relatively slow change stage. At the slow change stage, commonly used properties can be predicted well through linear models. In general, PAV aging does not reflect well the aging trends and characteristics of binders treated in the more natural conditions. Therefore, it is proposed to consider using natural aging to simulate asphalt binder aging for road pavements with high expectations on durability.

Impact of Nanoclays on Chemical Fractions and Mechanical Performance of Asphalt Binders

Asphalt binder often is modified to obtain better performance of the pavement. Some recent studies have considered nanoclay as an alternative to currently practiced styrene-butadiene-styrene (SBS) modification to reduce the asphalt binder’s overall cost. This study evaluated any notable changes in the chemical composition of the binder due to the nanoclay modification and investigated any correlation between the chemical composition and mechanistic properties of the asphalt binder. It was found that changes in the chemical composition of nanoclay-modified binders are crude source–dependent. After nanoclay modification, the binders that originated from the Arabian crude were found to be more acidic than the binders from the Canadian crude source. However, nanoclays did not have any notable impact on the polarity of the tested asphalt binders regardless of their crude sources. The saturates, aromatics, resins, and asphaltenes (SARA) analysis results of asphalt binders revealed that the n-heptane insoluble contents increased notably after modification with nanoclays, whereas the saturates content decreased due to aging. Some mechanical properties (e.g., viscosity and rutting factor) were found to be correlated with n-heptane insoluble contents. Moreover, the sessile drop analysis test result showed that the nanoclay-modified binders offered superior bonding with gravel than with sandstone. Multiple linear regression analyses suggest that there is a fair (R2=0.55) correlation between the binders’ SARA components and compatibility for gravel.

Comparative assessment of soil microbial community in crude oil contaminated sites

Petroleum refineries generate oily sludge that contains hazardous polycyclic aromatic hydrocarbons (PAH), and hence, its proper disposal is of foremost concern. Analysis of the physicochemical properties and functions of indigenous microbes of the contaminated sites are essential in deciding the strategy for bioremediation. This study analyses both parameters at two geographically distant sites, with different crude oil sources, and compares the metabolic capability of soil bacteria with reference to different contamination sources and the age of the contaminated site. The results indicate that organic carbon and total nitrogen derived from petroleum hydrocarbon negatively affect microbial diversity. Contamination levels vary widely on site, with levels of PAHs ranging from 5.04 to 1.66 × 103 μg kg−1 and 6.20 to 5.64 × 103 μg kg−1 in Assam and Gujarat sites respectively, covering a higher proportion of low molecular weight (LMW) PAHs (fluorene, phenanthrene, pyrene, and anthracene). Functional diversity values were observed to be positively correlated (p < 0.05) with acenaphthylene, fluorene, anthracene, and phenanthrene. Microbial diversity was the highest in fresh oily sludge which decreased upon storage, indicating that immediate bioremediation, soon after its generation, would be beneficial. Improvement in the bio-accessibility of hydrocarbon compounds by the treatment of biosurfactant produced by a (soil isolate/isolate) was demonstrated., with respect to substrate utilization.