Concentrations Of Hydrocarbons Research Articles

Influence of heavy Canadian crude oil on pristine freshwater boreal lake ecosystems in an experimental oil spill.

The overall impact of a crude oil spill into a pristine freshwater environment in Canada is largely unknown. To evaluate the impact on the native microbial community, a large-scale in situ model experimental spill was conducted to assess the potential role of the natural community to attenuate hydrocarbons. A small volume of conventional heavy crude oil (CHV) was introduced within contained mesocosm enclosures deployed on the shoreline of a freshwater lake. The oil was left to interact with the shoreline for 72h and then free-floating oil was recovered using common oil spill response methods (i.e. freshwater flushing and capture on oleophilic absorptive media). Residual polycyclic aromatic hydrocarbon (PAH) concentrations returned to near preoiling concentrations within 2 months, while the microbial community composition across the water, soil, and sediment matrices of the enclosed oligotrophic freshwater ecosystems did not shift significantly over this period. Metagenomic analysis revealed key polycyclic aromatic and alkane degradation mechanisms also did not change in their relative abundance over the monitoring period. These trends suggest that for small spills (<2l of oil per 15 m2 of surface freshwater), physical oil recovery reduces polycyclic aromatic hydrocarbon concentrations to levels tolerated by the native microbial community. Additionally, the native microbial community present in the monitored pristine freshwater ecosystem possesses the appropriate hydrocarbon degradation mechanisms without prior challenge by hydrocarbon substrates. This study corroborated trends found previously (Kharey et al. 2024) toward freshwater hydrocarbon degradation in an environmentally relevant scale and conditions on the tolerance of residual hydrocarbons in situ.

The influence of palm oil-derived plasticizers and lubricants on the rheological and mechanical properties of styrene butadiene rubber

Researchers have recently focused on green processing aids made from plants and vegetables to avoid the high concentration of polycyclic aromatic hydrocarbons (PAHs) from petroleum-based processing oils, which is hazardous to human health. This paper focuses on the effect of lubricants and plasticisers produced from palm oil on the rheological, mechanical and thermal aging properties of styrene-butadiene rubber (SBR). These lubricants and plasticisers are known as glycerol trioleate (GTO), n-butyl stearate (NBS), ethylene bis-steramide (EBS), ethylene bis-oleamide (EBO), pentaerythritol tetrastearate (PETS) and stearyl stearate. The abrasion performance, visual inspection appearance, and cure characteristics of the lubricants and plasticisers on SBR were examined and compared to processing oil-treated distillate aromatic extract (TDAE), paraffin wax, microcrystalline wax, polyethylene (PE) wax, epoxidised soybean oil (ESBO), and stearic acid. It discovered that rubber compounds based on GTO, stearic acid, and EBS exhibited better abrasion resistance and cure properties than rubber compounds based on processing oil. These samples were selected and subjected to mechanical properties, thermal aging effects analysis and comparison with processing oil. Tensile strength shows that SBR with EBS (22.49 MPa) and EBS with GTO (EBS/GTO; 21.25 MPa) are closely similar to SBR compounds with processing oil (21.02 MPa). The findings imply that EBS and EBS/GTO, green plasticisers and lubricants, are viable alternatives to petroleum-based processing oils while being cost-effective for tire production.

The Feasibility Study of In Situ Conversion of Oil Shale Based on Calcium-Oxide-Based Composite Materia Hydration Exothermic Reaction

Oil shale, as a vast potential resource, is considered an important alternative energy source, and its effective development and economic utilization are of significant importance in alleviating the contradiction between energy supply and demand. Presently, the in situ conversion technology for oil shale has gained significant global attention, with numerous extraction methods undergoing active research and development. One of these methods is the in situ conversion of oil shale based on the hydration reaction of calcium-oxide-based composite material (CaO-CM). This approach harnesses the heat produced by the reaction between CaO-CM and water as a heat source for the pyrolysis of oil shale. This paper conducted experiments to assess the feasibility of temperature associated with this method. The feasibility study mainly includes two aspects: First, it is necessary to investigate whether the temperature generated by the hydration reaction of CaO-CM can meet the temperature requirements for the pyrolysis of oil shale. Through pyrolysis experiments of Xinjiang oil shale, the minimum temperature required for oil shale pyrolysis was determined to be 330 °C. High-temperature and high-pressure reaction vessels were employed to explore the temperature generated by the hydration reaction of CaO-CM. The results show that with the increase in environment pressure, environment temperature, and reaction mass, the maximum temperature generated by the hydration reaction of CaO-CM also increases (reach 455.5 °C), meeting the temperature requirements for the pyrolysis of oil shale. Second, the study evaluates whether the hydration reaction of CaO-CM can induce pyrolysis hydrocarbons of the oil shale. Through the pyrolysis experiments of oil shale based on the hydration reaction of CaO-CM, the changes in the content of pyrolysis hydrocarbons (S2) in oil shale before and after pyrolysis are measured. The results show that under 10 MPa pressure, the content of pyrolysis hydrocarbons in the oil shale decreased from 40.96 mg/g to 0.08 mg/g after pyrolysis. This confirms the feasibility of the temperature conditions for the in situ conversion of oil shale based on the hydration reaction of CaO-CM.

Analysis of Heavy Metals and Petroleum Based Contaminants in Surface Water and Sediment near two Illegal Refining Sites in Niger Delta, Nigeria

The pollution of the environment from heavy metals and petroleum based contaminants in surface water and sediments resulting from illegal refining activities were looked at. The study was aimed at assessing the levels of heavy metals (Pb, Zn, Cu, Co, Cr, As, Cd and Ni), Benzene, Toluene, Ethyl-Benzene, and Xylene (BETX), Polycyclic Aromatic Hydrocarbons (PAHs) and Total Hydrocarbon Content (THC) in surface water and sediments. Samples were collected from two deactivated sites of illegal refineries in Oshika and Egbalor communities of Rivers State, Nigeria. The samples were analyzed for the contaminants which were compared with the World Health Organization (WHO) standard. The findings indicate that the surface water and sediments were highly polluted and may pose a health hazard to the community members that may use it for drinking.

Spatial distribution and policy implications of the exhaust emissions of two-stroke motorcycle taxis: a case study of southwestern state in Nigeria

Two-stroke motorcycles emit harmful exhaust fumes because of incomplete combustion. Although they constitute the main fleet of motorcycle taxis in sub-Saharan Africa, monitoring, spatial assessment, and regulation are weak, leaving dire health consequences in cities. This study collected motorcycle raw exhaust emissions of 1,950 two-stroke petrol-driven motorcycle taxis, otherwise called okada, in Ogun State, Nigeria, using an idle mode test approach under 10 minutes and employed correlations, hierarchical multiple linear regression models, and spatial analysis. It was found that carbon monoxide (CO) and hydrocarbons (HC) were the most highly concentrated, and the latter were beyond allowable limits. The concentration of CO was found to be at the minimum of 0.00 % and the highest being at 6.40% (an average of 1.05%), while the HC concentration was reported at the minimum of 18.00 ppm and the highest at 15446 ppm (an average of 3560 ppm). Notably, Kriging interpolation analysis indicated that cumulative effects due to the clustering and operations of motorcycle taxis could increase these concentrations over time, extending their long-term impacts. Given the severe effects of these emissions on health and the wider environment, a DPSIR policy framework is proposed to regulate two-stroke motorcycle taxis in sub-Saharan Africa.

Impact of Biosolids-Derived Biochar on the Remediation and Ecotoxicity of Diesel-Impacted Soil

This study aimed to investigate the impact of biosolids-derived biochar on the remediation of Australian soil contaminated with diesel while investigating the role of biochar in the remediation. To achieve the latter aim, sodium azide (NaN3) was added to a separate biochar treatment (BN) to alter the bacterial community structure. Biochar (B) reduced detectable hydrocarbons by 2353 mg/kg compared to the control (C) treatment at week 24. However, the BN treatment reduced the hydrocarbon concentration by 3827 and 6180 mg/kg, relative to B and C, respectively. Soil toxicity significantly decreased at week 24 compared to the start of the remediation in B, but not in the control. Biochar and control treatments generally showed a similar bacterial community structure throughout the incubation, while the bacterial community structure in BN differed significantly. Biodegradation was found to play a significant role in hydrocarbon removal, as the variation in the bacteria community coincided with differences in hydrocarbon removal between B and BN. The increased removal of hydrocarbons in the BN treatment relative to B coincided with increased and reduced relative abundances of Gordonia and JG30-KF-CM45 genera, respectively. This study showed that NaN3 led to a transient and selective inhibition of bacteria. This study makes an important contribution towards understanding the use of NaN3 in examining the role of biochar in the remediation of diesel-contaminated soil. Overall, we conclude that biochar has the potential to enhance the remediation of diesel-contaminated soil and that biodegradation is the dominant mechanism.

Reuse of Drill Cuttings Contaminated with Diesel in the Formation of Asphalt Pavement

Current Cuban strategies to increase hydrocarbon production introduce new hazardous waste such as drilling cuttings contaminated with diesel. In order to manage them safely, the present work aims to evaluate their potential to be reused in the construction industry, hence, it is intended to use the drilling cuttings contaminated with diesel as a partial replacement for the conventional raw material for the Manufacture of asphalt pavement. To determine the composition of the dry and wet drill cuttings, physical, chemical and mechanical tests were carried out that showed a hydrocarbon content of 3.2% and 6.9% respectively, higher than the maximum limit established for final disposal, due to the presence of diesel in the composition. Regarding its granulometry, it is evident that more than 70% of its particles are fine, so it can be used as a modifier of the granulometry of the aggregate. Different mixing ratios were established to improve their properties in the application proposal, obtaining viable results. In this regard, resistances of 46%, 33% and 32% higher than the minimum limit were obtained to be used in pavement patching actions as a subbase. Elements that drill cuttings can replace conventional raw materials such as aggregates or aggregates in the restoration of sub-base of asphalt pavements, this management alternative being beneficial from an environmental point of view.

Sourcing aliphatic and polycyclic aromatic hydrocarbons (PAHs) in Jinga shrimp (Metapenaeus affinis) muscle tissues and surface sediments (study case: Northwest Persian Gulf).

This study addresses the sources of aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the northwestern Persian Gulf and the muscle tissues of Jinga shrimp (Metapenaeus affinis), a commercially important aquatic species. In November 2018, 28 Jinga shrimp samples were systematically collected from four key fishing areas in Behrgan and Khormusi: Imam Khomeini Port (S1), Mahshahr Port (S2), Sejafi (S3), and Behrgan Wharf (S4). Additionally, sediment samples were collected from these locations, and AHs and PAHs concentrations were analyzed using gas chromatography-mass spectrometry (GC-MS). The average aliphatic concentration in Jinga shrimp was 4800.32 (μg g-1 DW), exceeding the sediment samples' 2496.69 (μg g-1 DW) estimate. Hydrocarbon component analysis revealed EPA priority list (PAH-16) and measured PAHs (PAH-29) concentrations in Jinga shrimp ranging from 1095.8 to 2698.3 (ng g-1 DW) and in sediments from 653.6 to 1019.5 (ng g-1 DW). Elevated AHs and PAHs in Jinga shrimp, compared to sediments, suggest a petrogenic source, notably at station S4 near Behrgansar and Nowruz oil fields. Low molecular weight (LMW) compounds dominated in both shrimp and sediment PAHs. Aliphatic composition profiles in shrimps closely mirrored sediment profiles, illustrating an even-to-odd carbon dominance gradient. Diagnostic ratio examinations of hydrocarbons indicated pervasive petroleum derivatives in the environment. This study establishes a direct correlation between hydrocarbon concentrations in shrimp and sediment samples and the corresponding aliphatic groups, PAH-16, and PAH-29. The findings underscore the potential of Jinga shrimp as a reliable indicator of hydrocarbon pollution in the northwestern Persian Gulf.

Ecological and Geochemical Assessment of the State of Soils in the City of Baikal’sk according to the Content of Polycyclic Aromatic Hydrocarbons

Ecological and Geochemical Assessment of the State of Soils in the City of Baikal’sk according to the Content of Polycyclic Aromatic Hydrocarbons

Burn pit-related smoke causes developmental and behavioral toxicity in zebrafish: Influence of material type and emissions chemistry

Combustion of mixed materials during open air burning of refuse or structural fires in the wildland urban interface produces emissions that worsen air quality, contaminate rivers and streams, and cause poor health outcomes including developmental effects. The zebrafish, a freshwater fish, is a useful model for quickly screening the toxicological and developmental effects of agents in such species and elicits biological responses that are often analogous and predictive of responses in mammals. The purpose of this study was to compare the developmental toxicity of smoke derived from the burning of 5 different burn pit-related material types (plywood, cardboard, plastic, a mixture of the three, and the mixture plus diesel fuel as an accelerant) in zebrafish larvae. Larvae were exposed to organic extracts of increasing concentrations of each smoke 6-to-8-hr post fertilization and assessed for morphological and behavioral toxicity at 5 days post fertilization. To examine chemical and biological determinants of toxicity, responses were related to emissions concentrations of polycyclic hydrocarbons (PAH). Emissions from plastic and the mixture containing plastic caused the most pronounced developmental effects, including mortality, impaired swim bladder inflation, pericardial edema, spinal curvature, tail kinks, and/or craniofacial deformities, although all extracts caused concentration-dependent effects. Plywood, by contrast, altered locomotor responsiveness to light changes to the greatest extent. Some morphological and behavioral responses correlated strongly with smoke extract levels of PAHs including 9-fluorenone. Overall, the findings suggest that material type and emissions chemistry impact the severity of zebrafish developmental toxicity responses to burn pit-related smoke.

Comprehensive the seasonal characterization of atmospheric submicron particles at urban sites in the North China Plain

To comprehensively investigate the seasonal variations in submicron particles (PM1 = NR-PM1 + BC) composition, sources and chemical processes, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), along with a multiangle absorption photometer (MAAP), was deployed to observe at urban sites in the North China Plain from October 1, 2015, to July 31, 2016. The PM1 average mass were 36.4 ± 39.0, 32.9 ± 20.7, 40.4 ± 52.4 and 99.0 ± 88.7 μg m−3 in spring, summer, autumn and winter, respectively. On the whole, the OA accounted for the largest component of PM1 during the four seasons, with the highest contribution in winter, accounting for 49% on average, followed by autumn (47%), spring (40%) and summer (31%). The secondary inorganic aerosol (SIA) mass concentration in summer was the lowest but contributed the most to PM1 in summer (62%), and it was higher than that in spring (46%), autumn (43%) and winter (41%). Positive matrix factorization (PMF) was used to differentiate the high-resolution mass spectra (HRMS) of organic aerosol (OA) into six factors, including two secondary OA (highly oxidized, low-volatility oxygenated organic aerosols (LV-OOA) and less oxidized, semi-volatile oxygenated OA (SV-OOA)) and four primary OA (including cooking-related OA (COA), hydrocarbon-like OA (HOA), biomass burning OA (BBOA) and coal combustion OA (CCOA)). OOA (LV-OOA + SV-OOA) exhibited the highest OA loading in summer (59%), while POA (CCOA + COA + HOA) exhibited the highest OA loading in winter (62%). The OA exhibited similar bimodal diurnal patterns during the four seasons, the nitrate and sulfate seasonal diurnal variations slightly differed, and the peak value occurred at night in winter and in the morning during the other seasons. The trend of the LV-OOA and SV-OOA diurnal variation in spring, autumn and winter appeared small difference, and the summer vary differently compared to other seasons. However, the diurnal mass concentration in winter was much higher than other seasons. The COA diurnal pattern peaked at noon and at night during the four seasons, corresponding to the peak hours of dining activities. The HOA, BBOA and CCOA seasonal diurnal patterns showed low concentrations during the daytime and high concentrations at night. OA on HPD was 6, 7 and 7 times higher than that on CD in spring, autumn and winter. The SIA concentration significantly increased on HPD in spring (69.3 μg m−3, 52%), autumn (80.6 μg m−3, 50%) and winter (82.4 μg m−3, 43%). The organic nitrate average mass concentrations were 0.6 ± 0.5, 0.7 ± 0.2, 0.8 ± 1.2 and 2.5 ± 2.3 μg m−3 in spring, summer, autumn and winter, respectively. The organic nitrate diurnal pattern appeared at night was higher than that during the daytime in spring, autumn and winter. The opposite diurnal pattern emerged in summer. The average mass concentration of polycyclic aromatic hydrocarbons (PAHs) during the entire observation period reached 73.2 ± 154.2 ng m−3, and the seasonal average mass were 30.4 ± 30.6, 10.7 ± 4.0, 40.5 ± 10.3 and 220.3 ± 246.7 ng m−3 in spring, summer, autumn and winter, respectively. The highest diurnal values in spring, summer, autumn and winter were 44.2, 11.7, 71.6 and 366.8 ng m−3, respectively.

Pre-cooking and liquid smoke affect the physicochemical and microbiological quality and polyhydroxy aromatic hydrocarbon (PAH) content in smoked skipjack tuna (Katsuwonus pelamis L.)

This study aimed to compare the quality of smoked fish products processed with liquid smoke with and without pre-cooking when stored at room temperature (25°C) for 0, 2, 4, and 6 days. The observations included moisture content, water holding capacity, color, and total plate and mold counts. The treated samples were also analyzed for polyhydroxyaromatic hydrocarbons (PAHs) at day 0. The study found that the pre-cooked products had a lower moisture content (55.1%) than the control (59.9%) during storage. Additionally, the pre-cooked product had a higher water holding capacity than the control. The TPC value indicates that the pre-cooked product meets the Indonesian standard for smoked fish up to the 2nd day of storage, whereas the control product only meets the standard on day 0. However, the total mold of the control products meets the Indonesian standard until the 2nd day of storage, while the pre-cooked products only meet the standard on day 0. The pre-cooked product had a higher lightness value (L*) than the control. The analysis of polyhydroxy aromatic hydrocarbon (PAH) showed that the pre-cooking process did not affect the concentration of PAH.

Shale oil development techniques and application based on ternary-element storage and flow concept in Jiyang Depression, Bohai Bay Basin, East China

The ternary-element storage and flow concept for shale oil reservoirs in Jiyang Depression of Bohai Bay Basin, East China, was proposed based on the data of more than 10 000 m cores and the production of more than 60 horizontal wells. The synergy of three elements (storage, fracture and pressure) contributes to the enrichment and high production of shale oil in Jiyang Depression. The storage element controls the enrichment of shale oil; specifically, the presence of inorganic pores and fractures, as well as laminae of lime-mud rocks, in the saline lake basin, is conducive to the storage of shale oil, and the high hydrocarbon generating capacity and free hydrocarbon content are the material basis for high production. The fracture element controls the shale oil flow; specifically, natural fractures act as flow channels for shale oil to migrate and accumulate, and induced fractures communicate natural fractures to form complex fracture network, which is fundamental to high production. The pressure element controls the high and stable production of shale oil; specifically, the high formation pressure provides the drive force for the migration and accumulation of hydrocarbons, and fracturing stimulation significantly increases the elastic energy of rock and fluid, improves the imbibition replacement of oil in the pores/fractures, and reduces the stress sensitivity, guaranteeing the stable production of shale oil for a long time. Based on the ternary-element storage and flow concept, a 3D development technology was formed, with the core techniques of 3D well pattern optimization, 3D balanced fracturing, and full-cycle optimization of adjustment and control. This technology effectively guides the production and provides a support to the large-scale beneficial development of shale oil in Jiyang Depression.

The Role of Zeolite (Microporous Crystalline Aluminosilicates) In Catalytic Pyrolysis of Waste High- and Low-Density Polyethylene Bags for Production of Fuel and Chemicals: A Review

This review provides a state-of-the-art summary of the role which zeolite plays as a catalyst via pyrolysis as a way of recovering fuels and chemicals from waste high and or low density polyethylene bags. It also highlighted the two types of zeolite (natural or synthetic) which are used as a two-stage pyrolysis−catalysis in giving a free waxing product to pure fuel and chemicals which can be subjected to further analyzing and or upgrading. As yield of oil/wax decreased with the addition of a zeolite as catalyst from 44 and 51 wt.%, (depending on the waste high density polyethylene “HDPE” or low density polyethylene bags “LDPE” and other factors). However, the composition of the pyrolysis−catalysis oils significantly increased in aromatic hydrocarbon content accordingly. In addition, the composition of the oils shifted from high molecular weight hydrocarbons (C16+) to fuel range hydrocarbons (C5−C15), with a high content of single-ring aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylenes, and styrene. This process shows great potential for production of fuels or chemicals, and also addresses the urgent issue of waste HDPE and or LDPE disposal.

Influence of retention time and catalyst concentrations on catalytic pyrolysis yields of polyethylene and polystyrene

ABSTRACT The present work focuses on enhancing the liquid fraction yields having hydrocarbons in the diesel fuel range from pyrolysis of PS/PE (1:1 wt.%) under the influence of ZSM–5 catalysts in an autoclave reactor. The pyrolysis product yields and their compositions were investigated for varied catalyst concentrations (0%, 5%, 7.5%, and 10%), reaction temperatures (250–500°C), and retention times (20–60 min). The physical and chemical characterization of the feedstocks, catalysts, and thermally and catalytically derived oils were carried out along with elemental analysis of the liquid products. It was observed that 7.5% catalyst concentration exhibited the maximum liquid fraction yields (71.2 wt.%) at 350°C and a retention time of 30 min. Catalytic cracking with a retention time of 20–30 min produced maximum liquid yields with aromatic, aliphatic, and isomerized hydrocarbon contents of 42.9%, 30.15%, and 14.3%, respectively. Expedite weakening of the catalytic activity of the ZSM-5 catalyst was observed with process retention time higher than 30 min. The calorific values of catalytically derived oils were found to be in the range of 44.2–44.8 MJ/kg, and their carbon numbers were between C11 and C19. Thus, these characteristics make these oils a potential candidate to be used as an alternative to diesel fuel. Further, the higher proportions of aromatics and aliphatic compounds present in catalytically derived oils compared to that obtained from thermal pyrolysis affirmed its superiority as a potential diesel substitute.

STUDY OF CATALYSTS BASED ON MESOPOROUS ALUMINOSILICATE IN THE DEAROMATIZATION PROCESS OF A MODEL MIXTURE: PHYSICO-CHEMICAL CHARACTERISTICS AND CATALYTIC ACTIVITY

The limitation on the content of aromatic hydrocarbons and sulfur is associated with environmental requirements according to Euro-5 standards. Upon combustion, these substances release highly toxic compounds into the atmosphere, adversely affecting human health and the surrounding environment. Additionally, a high concentration of aromatic hydrocarbons in diesel fuel significantly degrades its quality, leading to soot formation and reducing its cetane number. According to Euro-5 standards, the content of polycyclic aromatic hydrocarbons and sulfur compounds should not exceed 8% and 10 mg/kg, respectively. To address the challenge of producing high-quality diesel fuels, the hydrotreatment process is employed in the presence of heterogeneous catalysts.The article presents the synthesis of mesoporous aluminosilicates and bifunctional catalysts based on them to study the activity of the hydrotreatment process for a model mixture. The obtained samples were investigated using various physico-chemical methods such as SEM, low-temperature nitrogen adsorption/desorption, XRD, and FT-IR. It was established that the Ni/MAS-H-bentonite and Mo/MAS-H-bentonite catalysts exhibit high activity and selectivity in the hydrotreatment process under optimal conditions (240°C, 3 MPa, and 0.5 h-1).

Baltic Sea shipwrecks as a source of hazardous pollution

Background Shipwrecks on the Baltic Sea seabed pose a serious threat to the marine environment. Fuel, ammunition and chemicals in their holds can enter the ecosystem at any time, causing an ecological disaster. It is known that oil spills from ship accidents can affect life and health of different species of animals, both immediately after catastrophe and for many years thereafter. This article discusses the negative impact of shipwrecks on the ecological status of the Baltic Sea and presents the contamination status of bottom sediment core samples taken in the vicinity of shipwrecks located in the South Baltic, i.e., S/s Stuttgart, t/s Franken, S/T Burgmeister Petersen and m/s Sleipner. It is based on the results of research carried out by the Maritime Institute between 2011 and 2016. Methods Core samples were taken by a VKG-2 vibrating probe and analysed towards content of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), total petroleum hydrocarbons (TPHs) and total organic carbon (TOC). Seven PAHs and Seven PCBs were determined using solid phase extraction (SPE) technique followed by gas chromatography-mass spectrometry (GC-MS) detection. In order to determine the concentration of TPH, the SPE technique was applied followed by gas chromatography with flame ionisation detector (GC-FID) analysis. TOC content was established by TOC analyser using infrared detection. Results Samples taken in the vicinity of the S/s Stuttgart shipwreck have shown the highest concentrations of all analysed parameters compared to the examined wrecks and significantly differed from the results typical for these areas. This studies have shown that the S/s Stuttgart shipwreck poses a serious threat to the marine environment of Baltic Sea and it is necessary to continue studies in this area and to perform a wider range of analysis.

Evaluation method of oil saturation index OSI for shale oil reservoir based on well logging data

Oil saturation index (OSI) serves as an important indicator for potential movable hydrocarbons evaluation of shale oil reservoirs, which is mainly obtained through rock pyrolysis experiments. A new method is proposed to evaluate the OSI of shale quantitatively by NMR logging. The OSI value can be accurately obtained through the experimental measurement of organic carbon content (TOC) and rock pyrolysis of shale samples, which can identify the development of mobile hydrocarbons. Subsequently, the mobile fluid porosity can be obtained based on NMR logging. In order to establish the relationship between OSI value and mobile fluid porosity, it is important to determine the T2 cutoff value corresponding to the mobile fluid porosity. Take shale samples from the first member of the Qingshankou Formation (“Qing 1 Member”) as an example, based on 2D NMR experimental analysis in three different states (original, dried state at 105°C, saturated kerosene), the NMR T2 cutoff value of movable fluid porosity in the shale of Qing 1 Member is clarified as 8 ms. Integrating rock pyrolysis and 2D NMR experiments, it suggests that the NMR bin porosity with T2&amp;gt;8 ms has a good linear relationship with the OSI value obtained by pyrolysis analysis. The NMR bin porosity with T2&amp;gt; 8 ms reflects the OSI value of shale effectively. The larger the NMR bin porosity with T2&amp;gt;8 ms, the higher the mobile oil content of shale reservoir, which is consistent with the understanding of oil-bearing large pores in the Gulong Shale. The NMR bin porosity can continuously evaluate the vertical variation of the mobile hydrocarbon content. Compared with the traditional experimental measurement of finite depth points, this method has significant advantages, and can avoid the possibility of missing potentially movable oil layers.

Production of monocyclic aromatic hydrocarbons from microwave co-pyrolysis of polyethylene terephthalate and low-density polyethylene using coconut husk carbon as microwave absorbent

The application of biochar as microwave absorbers in microwave-assisted catalytic fast pyrolysis (MACFP) has been widely studied. It has been reported that coconut husk carbon (CHC) showed good process characteristics and product distribution as microwave absorbers. However, the existing studies did not pay much attention to the reusability of CHC absorbers. In this study, the CHC absorbers prepared from agricultural and forestry wastes were reused in multiple cycles in the MACFP of polyethylene terephthalate (PET) and low-density polyethylene (LDPE). Compared with typical microwave absorbers such as spherical silicon carbide (SiC) and granular activated carbon (GAC), CHC demonstrated favorable process characteristics with relatively high heating rate (29 °C/min) and short heating time (within 12 min). In terms of product properties, the highest liquid yield of 51.67 wt% and the highest content of monocyclic aromatic hydrocarbons (MAHs) of 82.82 % were obtained at the appropriate pyrolysis temperature (550 °C). After five consecutive uses, the CHC bed still produced comparable heating profiles and product distributions, compared to that of SiC. At the same time, a positive synergistic effect between PET and LDPE was observed. The co-feeding of PET and LDPE (50L50P) appropriately increased the liquid yield (42.50 wt% vs 38.75 wt%) and the relative content of MAHs (77.11 % vs 72.96 %) in comparison to their theoretical value. Finally, this study supplies a new strategy for utilizing recycled CHC as a microwave absorber for the treatment of hydrogen-rich and hydrogen-deficient mixed plastic wastes to produce MAHs products, which also reduces waste and realizes energy conversion.

Thermal processing of plastic wastes for fuel

Plastic wastes rise annually as a result of the growing demand for synthetic materials, which contributes to their manufacture. There are four main ways to recycle waste polymer, with thermal treatment for fuel being the most favorable to the environment. In this study, the thermal processing of plastic wastes was investigated with an anaerobic pyrolysis apparatus, and their thermal degradation was evaluated by using the thermogravimetric apparatus.Additionally, the elemental composition was determined by an elemental analyzer, n-alkanes were identified by gas chromatography with flame ionization detection/electron capture detector (GC-FID/ECD), and the hydrocarbons functional group was analyzed by Fourier transform infrared spectroscopy (FTIR). We pyrolyzed the most widely utilized polymers, including polypropylene (PP), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), at temperatures as elevated as 500°C to obtain plastic pyrolysis oil (PPO). Then PPO was distilled into initial boiling point (IBP)-200°C (gasoline-like fuel), 200-350°C (diesel-like fuel), and over 350°C fraction (residue), and the technical features of each fraction were compared to the MNS 0217:2006 and MNS 6861:2020 standards. Diesel-like fuel (DLF) derived from LDPE consists of the n-alkane hydrocarbons with C8–C23 identified by flame ionization detection (FID) data; C10–C17 represented more than 80% of them.The hydrotreatment results revealed that the diesel-like fraction's nitrogen (N) and sulfur (S) amounts could have reduced from 0.06% to 0.01% and from 0.78% to 0.29%, respectively. In conclusion, it could be done to generate a product with a more stable hydrocarbon content from plastic wastes for fuel.