Selective sorting of hexane isomers by anion-functionalized metal-organic frameworks with optimal energy regulation

Extensive efforts have been made to improve the separation selectivity of hydrocarbon isomers with nearly distinguishable boiling points; however, how to balance the high regeneration energy consumption remains a daunting challenge. Here we describe the efficient separation of hexane isomers by constructing and exploiting the rotational freedom of organic linkers and inorganic SnF62- anions within adaptive frameworks, and reveal the nature of flexible host-guest interactions to maximize the gas-framework interactions while achieving potential energy storage. This approach enables the discrimination of hexane isomers according to the degree of branching along with high capacity and record mono-/di-branched selectivity (6.97), di-branched isomers selectivity (22.16), and upgrades the gasoline to a maximum RON (Research Octane Number) of 105. Benefitting from the energy regulation of the flexible pore space, the material can be easily regenerated only through a simple vacuum treatment for 15 minutes at 25 °C with no temperature fluctuation, saving almost 45% energy compared to the commercialized zeolite 5 A. This approach could potentially revolutionize the whole scenario of alkane isomer separation processes.

The investigation on shale mechanical characteristics and brittleness evaluation

Rock mechanical property is significant for shale gas development and exploitation. Shale compressive strength, tensile strength, elastic deformation and so on, are necessary parameters for drilling, completion and fracturing work in shale formation. Among all these shale mechanical parameters, brittleness is a tricky and significant rock property, which has been widely used to hydraulic fracturing design. Currently, although so many works have been conducted to investigate shale brittleness, there is no precise definition of brittleness. In particular, there is no consensus on which method is the most reliable for shale brittleness evaluation. It is vital to figure out how to evaluate shale brittleness in a reliable method. Thus, this paper presents an experimental study on shale mechanical properties, analyzing mechanical features in stress strain curve, relation between mineral content and strength, mechanical parameters at varying confined stress. Based on shale mechanical characteristics and its brittle exhibition, stress strain curve from triaxial compression test is divided into 3 stages, namely, elastic stage, plastic stage and post peak stage. In combined with brittle characteristics in 3 stages of axial and radial stress-strain curves, a new brittleness index has been established for assessing shale brittleness. In order to prove the applicability of new brittleness index, its result is compared with shale failure sample after triaxial test and existing brittleness indexes based on mineral content, elastic deformation, energy, stress and strain, showing a good consistency and proving its practicability. Based on this brittleness index, influence factors of shale brittleness have been discussed. It is shown that elastic module is the most important factor of shale brittleness. Bedding plane makes shale brittleness have strong anisotropy. Brittleness is not only relied on its structure and mineral (like bedding plane, silicate and clay mineral content), but is also highly affected by external stress. Large confined pressure is able to impair shale brittleness. Outcome in this study can offer theoretical guidance for shale exploitation.

Construction and application of flow pressure drop model of perforated well considering pressure loss of perforation hole

Perforating well is one of the main production wells in reservoir development. Perforating effect directly affects well production, so the optimization of perforating parameters has attracted wide attention. Because pressure difference serves as the driving force for fluid flowing from formation to wellbore, it is important to understand the composition of production pressure difference in perforating well, which can guide the optimization of perforating parameters and the evaluation of perforating effect. In order to clarify the composition of production pressure difference during the production process of perforated wells, a pressure drop model pressure drop model is established based on fluid mechanics theory, which includes a pressure drop model of formation and a pressure drop model of perforation hole. The pressure drop model of formation is firstly constructed based on the Darcy's law and the equivalent resistance method, and the pressure drop model of perforation hole is built by the fluid tube-flow theory. Secondly, the numerical calculation method is adopted to realize the coupling solution of models, and the accuracy of this model is verified by comparison of the Karakas-Tariq model. Finally, the effects of formation physical properties and perforating parameters on flow pressure drop are discussed. The results show that there is a difference of more than 2 orders of magnitude between the pressure drop generated in perforation hole and flow pressure difference, and pressure drop of perforation hole can be neglected in practical applications. Comparing with medium-high permeability reservoirs, optimizing perforation parameters in low permeability reservoirs has a more significant impact on flow pressure drop. Among perforating parameters, perforation length and perforation density have great influence on flow pressure difference, while perforation diameter and phase angle have relatively little influence. These results have certain guiding significance for optimizing perforating parameters in different permeability reservoirs.

Investigation the effect of different ionic liquids based-aryl imidazole on the onset precipitation of asphaltene

Precipitation and deposition of asphaltene are considered as catastrophic issues facing the petroleum industry. Asphaltene deposition mainly occurs at variety places such as formation pore spaces, pumps, pipelines, wellbore, wellhead, tubing, surface facilities and safety valves causing operational problems, production deficiencies and enormous economic losses. This work aims to study the effect of series of synthesized aryl ionic liquids (ILs) containing different alkyl chains, named as R₈-IL, R₁₀-IL, R₁₂-IL, and R₁₄-IL, on the onset precipitation point of asphaltene in crude oil. R₈-IL, R₁₀-IL, R₁₂-IL, and R₁₄-IL were synthesized with high yields (the yield varied between 82 and 88%) and characterized via different tools of analysis (FTIR, ¹H NMR, and Elemental Analysis). Their Thermal Gravimetric Analysis (TGA) was investigated and showed a reasonable degree of stability. It was found that R₈-IL (short alkyl chain) has the highest stability, while R₁₄-IL (long alkyl chain) is the lowest one. Quantum chemical calculations were conducted to study the reactivity and geometry of their electronic structures. Moreover, surface and interfacial tension of them were studied. It was found that the efficiency of the surface active parameters increased by increasing the length of the alkyl chain. The ILs were evaluated to delay the onset precipitation point of asphaltene using to different methods; the kinematic viscosity and the refractive index. Results from the two methods showed delaying of onset precipitation after the addition of the prepared ILs. The asphaltene aggregates was dispersed due to the π-π* interactions and hydrogen bonds formation with the ILs.

Research on sand body architecture at the intersection of a bidirectional sedimentary system in the Jiyuan area of Ordos Basin

The exploration and development of the dual-provenance lower assemblage of the Yanchang Formation in the Jiyuan area has progressed rapidly. At the intersection of this bidirectional provenance system, a complex and variable spatial combination of sand bodies formed, resulting in significant structural heterogeneity in the development and distribution of reservoirs. Based on previous studies, this paper combines core data and logging data with a large number of analytical tests and production performance data to carry out research on the Chang 8₂-Chang 9 reservoir group in the lower assemblage of the Yanchang Formation in the Shijiawan-Buziwan area. Based on the analysis of sedimentary conditions, the sand body development pattern at the intersection of the bidirectional sedimentary system in the study area was analysed by stepwise dissection of the sand body architecture. After the types and characteristics of the 4th- to 5th-level architectural elements were determined, the spatial distribution of the combinations of these elements was assessed and combined with logging discriminant analysis and geometric shape prediction methods to identify a 'prism' architectural distribution pattern. The architectural elements are connected with the distribution of diagenetic facies, the spatial distribution patterns of different types of diagenetic facies under the constraints of the architecture are summarized by region, and the locations of potential favourable reservoir development are discussed. The results show that the degree of superposition and combination of the eight skeletal architectural elements in the target layers gradually deteriorate from the bottom to the top. In addition, the development scale and degree of architectural elements in the braided river delta system in the west are better than those in the meandering river delta system in the east. In the different sedimentary areas, the spatial combination styles of the architectural elements are quite different, and the combination of these elements gradually changes from a combination of braided channels (FA1) and abandoned channels (FA2) to a combination of underwater distributary channels (FA4). Matching of the distribution of diagenetic facies with the distribution of architectural elements reveals that the diagenetic facies dominated by intergranular pores and dissolution pores (associated with good reservoir physical properties) are usually found at the bottom or in the lower to middle parts of the skeletal architectural elements.

Analytical modification of EDFM for transient flow in tight rocks

The commercial development of unconventional resources with multiply fractured horizontal wells has been in the spotlight over the last ten years because of the significant contribution of unconventional oil and gas (UOG) reservoirs to the total US oil and gas production. UOG reservoirs contain multiscale fractures with heterogeneous properties, so the focus has been on efficient and accurate models that can account for these fractures individually. One of such models is the embedded discrete fracture model (EDFM), which has been applied to various types of fractured reservoirs. This work shows that the application of EDFM in fractured tight rocks yields significant errors because it cannot account for the expected transient flow between the matrix and fractures. To address the limitation when EDFM is used in tight rocks with structured Cartesian grids, we modified the matrix/fracture non-neighboring connection (NNC) flux in EDFM by multiplying it with a transient factor. We obtained this factor as in the transient matrix/fracture transfer term for dual-continuum models and implemented it in in our open-source shale simulator. We simulated a single vertical fracture in the middle of a tight reservoir with and without this EDFM modification and show the importance of the proposed modification. We also simulated cyclic gas enhanced oil recovery (CGEOR) in a fractured Bakken shale oil well and analyzed the model results using standard rate-transient analysis plots to evaluate the significance of the proposed modification. The results show that the standard EDFM underestimates oil and gas production by up to 73% at early times. This work presents the first analytical modification of EDFM to account for the nonlinear pressure drop expected near fracture surfaces. Comparing the modified and standard EDFM model results to a reference solution shows that the modified EDFM matches it. In contrast, the standard EDFM cannot match the reference solution when we use structured Cartesian grids with linear spacing. Additionally, by timing the simulation of a representative Bakken shale oil reservoir with 256 fractures, we show that the analytical modification proposed is only 1.5% slower than the standard EDFM.

Analysis of the 2016-2018 fluid-injection induced seismicity in the High Agri Valley (Southern Italy) from improved detections using template matching

Improving the capability of seismic network to detect weak seismic events is one of the timeless challenges in seismology: the greater is the number of detected and locatable seismic events, the greater insights on the mechanisms responsible for seismic activation may be gained. Here we implement and apply a single-station template matching algorithm to detect events belonging to the fluid-injection induced seismicity cluster located in the High Agri Valley, Southern Italy, using the continuous seismic data stream of the closest station of the INSIEME network. To take into account the diversity of waveforms, albeit belonging to the same seismic cluster, eight different master templates were adopted. Afterwards, using all the stations of the network, we provide a seismic catalogue consisting of 196 located earthquakes, in the magnitude range - 1.2 ≤ Ml ≤ 1.2, with a completeness magnitude Mc = - 0.5 ± 0.1. This rich seismic catalogue allows us to describe the damage zone of a SW dipping fault, characterized by a variety of fractures critically stressed in the dip range between ~ 45° and ~ 75°. The time-evolution of seismicity clearly shows seismic swarm distribution characteristics with many events of similar magnitude, and the seismicity well correlates with injection operational parameters (i.e. injected volumes and injection pressures).

Spotlight onto surfactant-steam-bitumen interfacial behavior via molecular dynamics simulation

Heavy oil and bitumen play a vital role in the global energy supply, and to unlock such resources, thermal methods, e.g., steam injection, are applied. To improve the performance of these methods, different additives, such as air, solvents, and chemicals, can be used. As a subset of chemicals, surfactants are one of the potential additives for steam-based bitumen recovery methods. Molecular interactions between surfactant/steam/bitumen have not been addressed in the literature. This paper investigates molecular interactions between anionic surfactants, steam, and bitumen in high-temperature and high-pressure conditions. For this purpose, a real Athabasca oil sand composition is employed to assess the phase behavior of surfactant/steam/bitumen under in-situ steam-based bitumen recovery. Two different asphaltene architectures, archipelago and Island, are used to examine the effect of asphaltene type on bitumen's interfacial behavior. The influence of having sulfur heteroatoms in a resin structure and a benzene ring's effect in an anionic surfactant structure on surfactant-steam-bitumen interactions are investigated systematically. The outputs are supported by different analyses, including radial distribution functions (RDFs), mean squared displacement (MSD), radius of gyration, self-diffusion coefficient, solvent accessible surface area (SASA), interfacial thickness, and interaction energies. According to MD outputs, adding surfactant molecules to the steam phase improved the interaction energy between steam and bitumen. Moreover, surfactants can significantly improve steam emulsification capability by decreasing the interfacial tension (IFT) between bitumen and the steam phase. Asphaltene architecture has a considerable effect on the interfacial behavior in such systems. This study provides a better and more in-depth understanding of surfactant-steam-bitumen systems and spotlights the interactions between bitumen fractions and surfactant molecules under thermal recovery conditions.

Genotoxic risk in occupational exposure to petrol and its amelioration by vitamin C and vitamin E

Petrol contains mixture of mutagens and carcinogens which have potential health risk after prolonged occupational exposure. We have compared genotoxicity and its amelioration in blood samples from 70 petrol pump attendants, working in congested area of the Ahmedabad city, India and similar number (n = 70) of Control samples from office workers dwelling in less polluted areas of the city. The cytokinesis-block micronucleus assay showed highly significant frequencies of micronucleus in Exposed than in the Controls. The sister chromatid exchanges were also significantly increased while the cell cycle proliferative index was significantly decreased in the Exposed individuals than the Controls. Addition of standardized doses of vitamin C and vitamin E in the lymphocyte cultures (in vitro) significantly improved all the biomarkers. The long-term occupational petrol exposure causes genotoxic effects and use of vitamins C and E for protection should be further explored in randomized controlled studies.

Microbiological Study in Petrol-Spiked Soil

The pollution of arable lands and water with petroleum-derived products is still a valid problem, mainly due the extensive works aimed to improve their production technology to reduce fuel consumption and protect engines. An example of the upgraded fuels is the BP 98 unleaded petrol with Active technology. A pot experiment was carried out in which Eutric Cambisol soil was polluted with petrol to determine its effect on the microbiological and biochemical properties of this soil. Analyses were carried out to determine soil microbiome composition-with the incubation and metagenomic methods, the activity of seven enzymes, and cocksfoot effect on hydrocarbon degradation. The following indices were determined: colony development index (CD); ecophysiological diversity index (EP); index of cocksfoot effect on soil microorganisms and enzymes (IFG); index of petrol effect on soil microorganisms and enzymes (IFP); index of the resistance of microorganisms, enzymes, and cocksfoot to soil pollution with petrol (RS); Shannon-Weaver's index of bacterial taxa diversity (H); and Shannon-Weaver's index of hydrocarbon degradation (IDH). The soil pollution with petrol was found to increase population numbers of bacteria and fungi, and Protebacteria phylum abundance as well as to decrease the abundance of Actinobacteria and Acidobacteria phyla. The cultivation of cocksfoot on the petrol-polluted soil had an especially beneficial effect mainly on the bacteria belonging to the Ramlibacter, Pseudoxanthomonas, Mycoplana, and Sphingobium genera. The least susceptible to the soil pollution with petrol and cocksfoot cultivation were the bacteria of the following genera: Kaistobacter, Rhodoplanes, Bacillus, Streptomyces, Paenibacillus, Phenylobacterium, and Terracoccus. Cocksfoot proved effective in the phytoremediation of petrol-polluted soil, as it accelerated hydrocarbon degradation and increased the genetic diversity of bacteria. It additionally enhanced the activities of soil enzymes.

Effect of occupational exposure to petrol and gasoline components on liver and renal biochemical parameters among gas station attendants, a review and meta-analysis

OBJECTIVES

Kidney and liver are of the most affected organs during permanent exposure to petrol and gasoline components in gas stations. This study aims to investigate the renal and liver involvements in these workers using meta-analysis.

METHODS

PubMed, Scopus, Science direct, ISI web of science, and Google scholar motor engine were searched using Mesh terms of the relevant keywords. Screening of titles, abstracts and full texts was continued until the eligible articles meeting the inclusion/exclusion criteria were selected. Quality assessment was conducted using NOS (Newcastle-Ottawa Quality score). The pooled standard mean difference of the renal and liver indices between exposed/unexposed groups was estimated using Stata ver. 11 software.

RESULTS

In this systematic review, 22 papers were entered. The pooled standard mean difference (95% confidence interval) between exposed and unexposed groups was estimated as of 0.74 (0.28, 1.21) for alkaline phosphatase (ALP), 2.44 (1.80, 3.08) for aspartate transaminase (AST), 2.06 (1.42, 2.69) for alanine transaminase (ALT), 0.10 (-0.09, 0.29) for total Bilirubin (TB), 0.74 (-0.42, -1.90) for total protein (TP), -0.49 (-0.82, -0.15) for albumin, 0.88 (-0.10, 1.87) for uric acid, 1.02 (0.45, 1.59) for creatinine and 1.44 (0.75, 2.13) for blood urea nitrogen (BUN).

CONCLUSION

Our meta-analysis showed that the serum AST, ALT, ALP, total protein, total bilirubin, BUN, uric acid and creatinine levels were higher among workers exposed to petrol and gasoline than control group, while albumin was lower in the serum of the exposed workers. Therefore, occupational exposure to gasoline stations can create adverse effects on kidney and liver function.

The effect of occupational exposure to petrol on pulmonary function parameters: a review and meta-analysis

Introduction Exposure to petrol and gasoline can have harmful effects on the lungs. This review aimed to summarize the reported effects of this exposure on pulmonary function parameters. Methods Relevant studies were identified by a comprehensive search in PubMed, Scopus, Science Direct and Google Scholar databases. Irrelevant studies were excluded. Quality assessment was performed using the Newcastle-Ottawa score (NOS). The standard mean difference of pulmonary parameters between exposed and unexposed petrol station attendants was pooled using random effects. Meta-regression was used to investigate factors probably related to heterogeneity. Studies affecting the total estimates were assessed during sensitivity analysis. The Egger test was performed to investigate any evidence of publication bias. Results Eventually, 26 studies entered the meta-analysis, and the pooled standard difference [95% confidence interval (CI)] of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, vital capacity (VC), peak expiratory flow (PEF), forced expiratory flow (FEF25-75) and maximum voluntary ventilation (MVV) in the exposed minus unexposed groups was -1.08 L (95% CI: -1.38, -0.78), -0.92 L (-1.15, -0.69), -0.65 (-1.01, -0.30), -0.51 L (-0.96, -0.06), -0.96 L/s (-1.21, -0.69), -0.78 L/s (1.14, -0.42) and -0.58 L/min (-0.90, -0.27), respectively, and showed a decrease in all pulmonary parameters in the exposed group. Conclusion Occupational exposure to petrol fumes is a risk factor for lung function and there is a reverse relation between lung function and the duration of exposure.

Lethal explosions in a non-terrorist civilian setting

A study was undertaken to investigate the range and nature of deaths that may result from explosions in a civilian population that has not been exposed to terrorist attacks or significant military activities. A search was conducted of autopsy files at Forensic Science SA, Adelaide, Australia, from July 2000 to June 2017 for all cases where death had been attributed to an explosion. Twenty cases were identified, consisting of 10 accidents, five suicides, two homicides, one murder-suicide with two decedents and one case where the manner of death was undetermined. Explosives were involved in nine deaths, petrol in seven and propane/butane/natural gas in a further four. Deaths caused by explosions were a rare event, with most cases being caused by accidents in a domestic or industrial environment. Although suicides formed the next most-common group, it is possible that explosions caused by petrol in cases of self-immolation were not intended.

Genetic, Reproductive and Hematological Toxicity Induced in Mice Exposed to Leachates from Petrol, Diesel and Kerosene Dispensing Sites

BACKGROUND

With a population of over 165,000,000, growing at an average rate of 2.7% per annum and an economic growth rate of about 5.7% in the past five years, the market for refined petroleum products in Nigeria is growing. As a result, the number of filling stations is increasing.

OBJECTIVES

The present study evaluated the reproductive and genetic toxicity of simulated leachate of soil from petrol, diesel and kerosene dispensing sites in a filling station using the murine sperm abnormality test, sperm count and bone marrow micronucleus assay.

METHODS

Simulated leachate of soil collected from petrol, diesel and kerosene dispensing sites in a filling station was intraperitoneally administered to mice at different concentrations. Bone marrow micronucleus assay was carried out after 5-days exposure, while sperm morphology assay was carried out 35 days from the first day of exposure. Alterations to hematological parameters were evaluated and physico-chemical analysis of the leachate samples was also carried out.

RESULTS

The results showed a significant (p<0.05) concentration-dependent increase in abnormal sperm cells and decrease in mean sperm count in all the samples tested. Increased induction of micronucleated polychromatic erythrocytes was observed in the exposed mice. Hematological analysis showed a significant (p<0.05) increase in the values of white blood cell count (WBC), lymphocytes, neutrophils, monocytes, eosinophils and mean corpuscular volume (MCV), while a significant (p<0.05) reduction in basophils, hemoglobin, mean corpuscular hemoglobin (MCH), packed cell volume and mean corpuscular hemoglobin concentration (MCHC) values were observed.

DISCUSSION

In the present study, simulated leachates from soil obtained from petrol, diesel and kerosene dispensing sites were shown to cause genomic disruptions in germ and somatic cells, and hematotoxicity in an animal model. These observed reproductive, genetic and hemato-toxicities are believed to be caused by the presence of lead, copper, mercury, polycyclic aromatic hydrocarbons, and benzene in the samples.

CONCLUSIONS

This study showed the negative impact of petroleum products in the contamination of soil, with a capability of inducing genetic damage in somatic and germ cells of exposed plants and animals.

ETHICS APPROVAL

The study was approved by the ethical committee of the Federal University of Technology, Akure, Ondo State, Nigeria.

A Temporal Association between Accumulated Petrol (Gasoline) Lead Emissions and Motor Neuron Disease in Australia

Background: The age standardised death rate from motor neuron disease (MND) has increased from 1.29 to 2.74 per 100,000, an increase of 112.4% between 1959 and 2013. It is clear that genetics could not have played a causal role in the increased rate of MND deaths over such a short time span. We postulate that environmental factors are responsible for this rate increase. We focus on lead additives in Australian petrol as a possible contributing environmental factor. Methods: The associations between historical petrol lead emissions and MND death trends in Australia between 1962 and 2013 were examined using linear regressions. Results: Regression results indicate best fit correlations between a 20 year lag of petrol lead emissions and age-standardised female death rate (R² = 0.86, p = 4.88 × 10⁻²³), male age standardised death rate (R² = 0.86, p = 9.4 × 10⁻²³) and percent all cause death attributed to MND (R² = 0.98, p = 2.6 × 10⁻⁴⁴). Conclusion: Legacy petrol lead emissions are associated with increased MND death trends in Australia. Further examination of the 20 year lag between exposure to petrol lead and the onset of MND is warranted.

Oxidative status in rat kidney exposed to petroleum hydrocarbons

Objective:

The study investigates the possible role of oxidative stress on renal tissues in association with petroleum hydrocarbon-induced nephrotoxicity.

Materials and Methods:

Rats of comparable weights were randomly distributed into 10 groups: Control and groups exposed to kerosene, petrol, and diesel via inhalation, contamination by food, and contamination by water. The exposure lasted for eight weeks.

Results:

Exposure to petroleum hydrocarbon led to significant rise in serum urea and creatinine, and renal tissue malondialdehyde. It also caused significant reduction in urinary urea and creatinine, and reduced glutathione, superoxide dismutase, and catalase activities of renal tissue homogenate. However, serum and urine concentrations of albumin and total protein were comparable in all groups.

Conclusion:

Results from this study shows that exposure to petroleum hydrocarbon led to renal dysfunction via oxidative stress, increasing lipid peroxidation and reducing the antioxidant defense mechanism.

Petrol-inhalation dependence : a case report

Ms M. a 13 years old class III student presented with one year history of petrol fumes inhalation dependence and six months history of kerosene inhalation dependence. She liked the smell of fumes getting pleasant feeling of well-being and increased confidence. She though fulfilled all the criteria of inherent dependence differed from typical cases described in published reports. Like male preponderance and group activity, the prominent features of inhalation dependence were absent in our case.