Concentrations Of Sulfur Compounds Research Articles

Effects of the depth of hydro desulfurization of raw materials on the yields of catalytic cracking products

The article is devoted to the problem of complex processing of oil feedstock and increasing the output of light petroleum products, in particular, catalytic cracking gasoline. Currently, the oil refining industry of Kazakhstan is faced with the task of complex processing of hydrocarbon raw materials, increasing the depth of processing and output of light petroleum products. In this connection it is urgent to solve the problem of lack of raw materials for oil refineries of the Republic of Kazakhstan. The complexity of solving the problem of processing residues of oils, fuel oil and intermediates of secondary processes lies in the fact that they contain a large amount of various sulfur compounds. This problem concerns not only domestic refineries, for example, oil from Uzbekistan fields contains a relatively large amount of SO2 compounds, which in turn contains about 1.28% sulphur. The high content of sulfur compounds in oil not only negatively affects the quality and environmental friendliness of manufactured products, but also reduces the service life of equipment and oil refineries. In this regard, the preparation and hydrodesulfurization of raw materials is one of the main issues of intensifying the process of catalytic cracking of petroleum raw materials of "PKOP" LLP. The issues of possibility of modernisation of catalytic cracking process units by including the process of hydrodesulphurisation of feedstock in order to improve the quality and yield of light products when using fuel oil and secondary intermediates having a large volume of various sulphur compounds in their composition have been considered by the authors. To evaluate the influence of the depth of hydrodesulfurisation of feedstock on the yields and composition of catalytic cracking products, the cracking of crude and hydrotreated hydrogenated vacuum gas oil mixed with fuel oil was carried out on a laboratory unit. The experiments were carried out on a fluidised catalyst bed at mass feed rates of 2h-1 and 4h-1, catalyst to feed ratio of 3:1 and temperature equal to 5100 C. The analysis of the experimental data obtained showed that preliminary hydrotreating of a mixture of vacuum gas oil and sulfur fuel oil followed by catalytic cracking increases the depth of oil refining and helps to increase the yield of catalytic distillate, improves its quality, which ultimately leads to a decrease in environmental pollution with sulfur compounds.

Exploring the Impact of Extended Maceration on the Volatile Compounds and Sensory Profile of Monastrell Red Wine

Volatile organic compounds (VOCs) are crucial to the wine’s overall quality since they define the aromatic profile. The aim of this study was to investigate whether a 146-day extended maceration (EM) treatment positively affects the aromatic and sensory properties of Monastrell red wine. A total of 43 aromatic compounds belonging to different chemical classes were identified using solid-phase microextraction combined with gas chromatography–mass spectrometry (SPME/GC-MS). In general, EM treatment decreased both the number and total relative concentration of VOCs. Specifically, EM decreased the concentration of alcohols, terpenes and sulphur compounds compared to control wines. However certain compounds such as 2-ethyl-1-hexanol, phenylethyl and ethyl decanoate significantly increased with prolonged maceration. Conversely, EM treatment did not significantly affect the total relative concentrations of esters and ketones. From sensorial point of view, the triangular test showed a positive identification of wines (10/18) with a significant preference for EM wines. Moreover, descriptive analysis revealed that EM wines scored lower values in appearance, aroma and taste. Future research should aim to optimize maceration time to enhance the content of VOCs without compromising the sensory quality of the wine.

Comparison of Emission Properties of Sustainable Aviation Fuels and Conventional Aviation Fuels: A Review

In order to achieve the International Air Transport Association’s (IATA) goal of achieving net-zero emissions in the aviation industry by 2050, there has been a growing emphasis globally on the technological development and practical application of sustainable aviation fuels (SAFs). Discrepancies in feedstock and production processes result in differences in composition between SAFs and traditional aviation fuels, ultimately affecting the emission performance of the two types of fuel. This paper discusses the impact of CO2/NOx/SO2/CO/PM/UHC emissions from the aviation industry on the natural environment and human health by comparing the two types of fuel under the same conditions. Fuel combustion is a complex process in the combustor of an engine, which transfers chemical energy into heat energy. The completeness of combustion is related to the fuel properties, including spray, evaporation, and flammability. Therefore, engine performance is not only affected by fuel performance, but also interacts with engine structure and control laws. The CO2 emissions of SAFs differ significantly from traditional aviation fuels from a lifecycle analysis perspective, and most SAFs can reduce CO2 emissions by 41–89%. Compared with traditional aviation fuels, SAFs and blended fuels can significantly reduce SO2 and PM emissions. Pure Fischer–Tropsch hydroprocessed synthesized paraffinic kerosine (FT-SPK) can reduce SO2 and PM emissions by 92% and 70–95% respectively, owing to its extremely low sulfur and aromatic compound content. In contrast, the differences in NOx emissions between the two types of fuel are not significant, as their generation mechanisms largely stem from thermal drive and turbulent flow in the combustor, with emissions performance being correlated to power output and flame temperature profile in engine testing. CO and UHC emissions are related to engine operating conditions and the physical/chemical properties of the SAFs, with no significant upward or downward trend. Therefore, SAFs have significant advantages over conventional aviation fuels in terms of CO2, SO2, and PM emissions, and can effectively reduce the hazards of aviation to the environment and human health.

«Lace Miracle», lichens as an indicator of the ecological situation using the example of Turkey Creek, Florida

In this article, we took a walk-exploration of a piece of paradise called Turkey Creek in the center of Florida. Enjoying the spring period of the awakening of nature, accompanied by a multitude of birds and other unique sounds of the inhabitants of Turkey Creek, we paid special attention to the diversity of lichens, which, as bioindicators, react and reflect the state and quality of the environment. Lichens are very sensitive to air pollution and die when there is a high content of carbon monoxide, sulfur compounds, nitrogen and fluorine. The degree of sensitivity varies among species, so they can be used as living indicators of environmental cleanliness. Based on the composition of lichens, the concentration of various pollutants in the air can be quantified using developed scales and formulas. Lichens are a unique group of lower plants. Lichens combine two organisms with opposite properties: an alga (usually green), which creates organic matter through the process of photosynthesis, and a fungus that consumes this substance. Lichens are characterized by fairly high tolerance to climatic factors and sensitivity to environmental pollutants and are widely used as environmental indicators. Lichens contain many macro- and microelements, organic acids, hormones and enzymes. Vitamins are produced by lichens in very small quantities. Lichens produce specific substances that are not found in other organisms (lichen starch, lichen acids, etc.). Lichens have the ability to extract various elements from the environment and accumulate in their thallus. The number of currently known lichen substances exceeds 250, of which 75 are found only in lichens. Lichens are indicators of the environmental situation. Our goal is to find out whether recreational load affects the state of the environment in people’s recreation areas. We carried out our study of the state of the environment in the state of Florida in the Turkey Creek natural park. This territory was chosen because the natural complexes of the area are characterized by high environment-forming, environmental, and recreational significance. In the last decade, the anthropogenic load on ecosystems associated with the recreational use of the territory has been increasing. It is worth familiarizing yourself with the types of lichens that were seen in the study area.

Eco-friendly catalyst in ultrasonic-assisted oxidative desulfurization of dibenzothiophene compound

10 W t.% WO3@activated carbon was prepared from apple peel and used as a catalyst in ultrasonic-assisted oxidative desulfurization of dibenzothiophene@octane in the presence of H2O2 as an oxidant. The physical characteristics of the prepared catalyst were investigated using X-ray diffraction, N2-adsorption-desorption, and scanning electron microscope. The reaction time, oxidant dose, catalyst dose, and sulfur compound concentration were studied to reach 99 % dibenzothiophene removal at ambient conditions and after four cycles the efficiency of dibenzothiophene removal can reach 97.7 %. The kinetic parameters were studied and indicate the ultrasonic-assisted oxidative desulfurization reaction is pseudo-second order.

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).

Prediction of sulfur compounds and total sulfur contents in catalytic cracking products of hydrotreated and non-hydrotreated feeds

Relevance. The lack of a reliable mathematical model suitable for predicting the yield and quality of products in catalytic cracking units, with an assessment of the environmental indicators of fuel fractions when changing the hydrocarbon composition and distribution of sulfur compounds in the process feedstock, as well as the possibility of involving highly sulfur-containing oil streams in processing on existing catalytic cracking units. Aim. To develop and apply a mathematical model of the catalytic cracking to predict the content of sulfur compounds and total sulfur in the products during the processing of hydrotreated and non-hydrotreated petroleum feedstocks. Methods. A complex of experimental methods, including liquid and gas chromatography to determine the composition of the feedstock and the distribution of sulfur compounds in the feedstock and catalytic cracking products, methods of quantum chemical modeling of reactions involving sulfur compounds, as well as numerical methods for processing and solving systems of differential equations. Quantum chemical modeling methods were used to study the thermodynamic parameters of catalytic cracking reactions involving sulfur-containing compounds. Results. The authors have developed and implemented in software a mathematical model of catalytic cracking involving hydrocarbons C1–C40+ and sulfur compounds (thiophenes C0–C4, alkylbenzothiophenes C0–C6, C0–C3 dibenzothiophenes, and C4–dibenzothiophene-benzonaphthothiophenes). The model aims to predict the yield and composition of process products, as well as the environmental indicators of motor fuels. Thermodynamic and kinetic parameters of catalytic cracking reactions were determined using quantum chemical modeling methods and solving the inverse kinetic problem.

Volatile sulfur compounds in asthmatic children and adolescents: A cross-sectional study in breath and saliva.

Halitosis in children implies psychosocial repercussions. Risk factors associated with this condition are unclear, and detection methods are inaccurate. To quantify the levels of sulfur-like compounds in children with asthma and healthy children from a novel validated assay, and to establish the risk factors related to halitosis. One hundred and twenty-eight individuals (63 healthy and 65 asthmatic) from 3 to 17 years of age were tested using a passive colorimetric sensor to measure the levels of sulfur-like compounds in breath and saliva. Information was collected on oral hygiene habits, gingival and dental health, breathing type, and dental malocclusion. The mean values of hydrogen sulfide were 4.0 ± 6.8 and 19.7 ± 12.2 ppbv (parts per billion in volume) in the control and asthmatic groups, respectively (p < .001). The presence of higher concentrations of sulfur compounds was significantly associated (p < .05) with the presence of gingival inflammation, tongue coating, dental plaque, mouth breathing, hypomineralization, age, tongue brushing, and the use of dental floss. The level of sulfur in breath and saliva was significantly higher in patients with asthma. These results can serve as a precedent to raise awareness among paediatricians and parents about oral hygiene care in children and adolescents.

Effects of a novel dental chew on oral health outcomes, halitosis, and microbiota of adult dogs.

Halitosis in dogs is an initial indication of periodontitis, highlighting its significance as a vital marker for underlying problems. Moreover, the oral microbial population has a significant influence on periodontal disease. Measuring the oral microbiota may be used in addition to breath odor, dental plaque, and gingivitis scoring to assess the impact of dental chews on oral health. In this study, we aimed to determine the differences in breath odor, oral health outcomes, and oral microbiota of adult dogs consuming a novel dental chew compared with control dogs consuming only a diet. Twelve healthy adult female beagle dogs were used in a crossover design study. Treatments (n = 12/group) included: diet only (control) or the diet + a novel dental chew. Each day, one chew was provided 4h after mealtime. On days 1, 7, 14, 21, and 27, breath samples were analyzed for total volatile sulfur compound concentrations using a halimeter. On day 0 of each period, teeth were cleaned by a veterinary dentist blinded to treatments. Teeth were scored for plaque, calculus, and gingivitis by the same veterinary dentist on day 28 of each period. After scoring, subgingival and supragingival plaque samples were collected for microbiota analysis using Illumina MiSeq. All data were analyzed using SAS (version 9.4) using the Mixed Models procedure, with P < 0.05 being significant. Overall, the dental chews were well accepted. Dogs consuming the dental chews had lower calculus coverage, thickness, and scores, lower gingivitis scores, and less pocket bleeding than control dogs. Breath volatile sulfur compounds were lower in dogs consuming the dental chews. Bacterial alpha-diversity analysis demonstrated that control dogs had higher bacterial richness than dogs fed dental chews. Bacterial beta-diversity analysis demonstrated that samples clustered based on treatment. In subgingival and supragingival plaque, control dogs had higher relative abundances of potentially pathogenic bacteria (Pelistega, Desulfovibrio, Desulfomicrobium, Fretibacterium, Helcococcus, and Treponema) and lower relative abundances of genera associated with oral health (Neisseria, Actinomyces, and Corynebacterium). Our results suggest that the dental chew tested in this study may aid in reducing periodontal disease risk in dogs by beneficially shifting the microbiota population and inhabiting plaque buildup.

Disentangling the Tissue-Specific Variations of Volatile Flavor Profiles of the Lentinula edodes Fruiting Body.

For Lentinula edodes, its characteristic flavor is the key determinant for consumer preferences. However, the tissue-specific volatile flavor variations of the fruiting body have been overlooked. Here, we comprehensively investigated the volatile flavor profiles of different tissues, including the pileus skin, context, gill, and stipe of the fruiting body, of two widely cultivated L. edodes strains (T2 and 0912) using the gas chromatography-mass spectrometry (GC-MS) technique combined with a multivariate analysis. We show that the eight-carbon and sulfur compounds, which represented 43.2-78.0% and 1.4-42.9% of the total volatile emissions for strains 0912 and T2, respectively, dominated their volatile profiles. Compared with strain T2, strain 0912 had a higher total content of eight-carbon compounds but a lower total content of sulfur compounds in the fruiting body. The sulfur compounds represented 32.2% and 42.9% of the total volatile emissions for strains 0912 and T2, respectively. In contrast, they constituted only 1.4% in the stipes of strain 0912 and 9.0% in the skin of strain T2. The proportions of the predominant C8 compounds (1-octen-3-one, 1-octen-3-ol, and 3-octanone) and sulfur compounds (lenthionine, 1,2,4-trithiolane, dimethyl disulfide, and dimethyl trisulfide) changed depending on the tissues and strains. Using machine learning, we show that the prediction accuracy for different strains and tissues using their volatile profiles could reach 100% based on the highly diverse strain- and tissue-derived volatile variations. Our results reveal and highlight for the first time the comprehensive tissue-specific volatile flavor variations of the L. edodes fruiting body. These findings underscore the significance of considering strain and tissue differences as pivotal variables when aiming to develop products with volatile flavor characteristics.

Response of distributions and emissions of summer biogenic sulfur in the Pacific Arctic to enhanced Pacific Water inflow

AbstractThe inflow of warm and nutrient‐rich Pacific Water (PW) through the Bering Strait into the Arctic Ocean is likely to have far‐reaching consequences for the ecosystem and biogenic sulfur cycle in the Earth's sensitive subarctic–arctic region of the Pacific sector, even impacting climate change under global warming scenarios. We performed a detailed biogeochemical study of summer biogenic sulfur cycling from cold (2012) to warm (2014) years in the Bering Strait and the Chukchi Sea, so as to highlight the importance of enhanced Pacific inflow in driving dimethylsulfide (DMS) variability. In the Bering Strait, the enhanced Pacific inflow led to the vertical expansion of the eastern high‐DMS regions due to the vertical extension of Alaska Coastal Water, and the horizontal expansion of the western surface high‐DMS regions due to the westward intrusion of Bering Shelf Water. The enhanced extension of PW potentially stimulated seawater warming, the northward retreat of the ice edge, and the enlargement of sea ice‐free areas in the Chukchi Sea. The northern ice melting zone at 71°N with a bloom of phytoplankton was an area of locally high dimethylsulfoniopropionate concentrations and slow DMS consumption in 2012. A hotspot for dimethylated sulfur compound concentrations and DMS sea–air flux occurred in the convergence region near 67.7°N during 2014, due to enhanced mixing caused by increased Bering Sea Water. Owing to the increased advection of PW during 2012–2014, surface DMS and its emission to the atmosphere increased sharply by threefold in the Chukchi Sea.

Sonochemical synthesis of heterostructured ZnO/Bi2O3 for photocatalytic desulfurization

In this study, metal oxides nanoparticles heterogeneous photocatalysts prepared by coprecipitation and ultrasonic techniques were used for diesel desulfurization. They were characterized by scanning electron microscope, powder X-ray diffraction, energy dispersive analysis, diffused reflectance spectra, photoluminescence analysis and BET surface area. The surface area of catalyst B is larger than catalyst A confirming its higher reactivity. X-ray reflectance spectroscopy was used to analyze the sulfur contents in feed. Thiophene was used as a model fuel to evaluate the photocatalytic activity of catalysts A and B. Using the Scherrer equation, sharp and intense signals suggesting their higher degrees of crystallinity, with average crystal sizes for ZnO, Bi2O3, catalysts A and B, respectively; of 18, 14.3, 29.7, and 23.8 nm. The operational parameters of the desulfurization process were optimized and have been studied and the maximum sulfur removal was achieved via a further solvent extraction step. A diesel fuel with a 24 and 19 ppm sulfur content and hence a total sulfur removal of 94.6% and 95.7% was acquired for catalysts A and B, respectively (sulfur compounds concentration in diesel fuel feedstock was 450 ppm). These findings demonstrated that photocatalysts A and B are good and effective catalysts for desulfurization of diesel fuel.

Spatiotemporal accumulation differences of volatile compounds and bacteria metabolizing pickle like odor compounds during stacking fermentation of Maotai-flavor baijiu.

Pickle like odor (PLO) is undesirable in Maotai-flavor baijiu; however, its formation mechanism is unclear. Furthermore, there is a lack of understanding of the spatiotemporal accumulation of volatile compounds (including PLO compounds, PLOC) and of the microorganisms responsible for the production of PLOC during stacking fermentation. In this study, we analyzed the spatiotemporal distribution differences of 132 volatile compounds in piled fermented grains. PLOC (n=5) were higher in pile surface than in pile center, reaching their highest levels at 6th and 5th rounds, respectively. The microorganisms in pile center were more conducive to the formation of alcohols, while those in the pile surface more promoted the synthesis of esters. Rhodococcus and Zygosaccharomyces promoted the formation of PLOC. Acetobacter was negatively correlated with the content of sulfur compounds by promoting their conversion into non-volatile sulfur compounds, thereby reducing the content of PLOC. This study provides information on the spatiotemporal differences of volatile compounds (especially PLOC) in piled fermented grains and identified the microorganisms that produce PLOC.

Agrivoltaic Farming Insights: A Case Study on the Cultivation and Quality of Kimchi Cabbage and Garlic

Agrivoltaic systems, which combine the cultivation of crops with solar panel installations, offer a novel solution to the dual challenges of energy production and agricultural productivity. This research verifies the impact of agrivoltaic (APV) conditions on the growth and quality of garlic and kimchi cabbage over two consecutive years in Naju-si, Jeollanam Province, Republic of Korea. In the 2019–2020 cultivation season, both kimchi cabbage and garlic grown under APV conditions experienced weight reductions of 18% and 15%, respectively, when compared to those grown in conventional settings. Intriguingly, despite the altered light conditions of APV leading to microenvironmental changes (mainly 41% light reduction), the quality of these crops, particularly in terms of their sulfur compound concentrations, remained consistent. This suggests that there was no discernible difference in the sensory quality of APV-grown kimchi cabbage and garlic compared to their traditionally grown counterparts. These findings highlight the potential of APV systems in promoting sustainable agriculture by balancing both crop yield and quality. Based on these results, the study suggests three innovative cultivation techniques to enhance crop growth in APV environments.

Insights into effects of thermotolerant nitrifying and sulfur-oxidizing inoculants on nitrogen-sulfur co-metabolism in sewage sludge composting

In this study, high temperature thermotolerant nitrifying bacteria (TNB) and high temperature thermotolerant sulfide oxidizing bacteria (TSOB) were obtained from compost samples and inoculated into sewage sludge (SS) compost. The effects of inoculation on physical and chemical parameters, ammonia and hydrogen sulfide release, nitrogen form and sulfur compound content change and physical-chemical properties during nitrogen and sulfur conversion were studied. The results showed that inoculation of TNB and TSOB increased the temperature, pH, OM degradation, C/N ratio and germination index (GI) of compost. Compared with the control treatment (CK), the addition of inoculants reduced the release of NH3 and H2S, and transformed them into nitrogen and sulfur compounds, the hydrolysis of polymeric ferrous sulfate was promoted, resulting in relatively high content of sulfite and sulfate. At the same time, the physical and chemical properties of SS have a strong correlation with nitrogen and sulfur compounds.

Exploring the link between sulphur-containing compounds and noxious odours at waste management facilities: implications for odour monitoring and mitigation strategies.

With this study we challenge the widely held assumption that sulphur-containing compounds in ambient air are good indicators of the presence noxious odours near waste management facilities. We analysed an extensive set of olfactometric data and data on the concentrations of hydrogen sulphide and trace sulphur compounds (TSCs) near a waste management facility in Croatia in 2021. The results show that the presence of noxious odours significantly correlates only with the concentrations of hydrogen sulphide and methyl mercaptan in ambient air but not with other measured TSCs. Thus, in addition to the measurement of pollutants in ambient air, Integrated Pollution and Prevention Control (IPPC) permits should mandate olfactometric measurements to detect and mitigate noxious odours near waste management facilities.

Adsorption-catalytic method for reducing the content of sulphur compounds in gas condensate diesel fuel

Gas condensate diesel fuels, being an excellent resource base, often do not meet modern standards of the cetane number value and the content of sulfur compounds (SC). Currently, Euro 5 and Euro 6 (<10 ppm sulfur content) diesel motor fuels are produced worldwide. High-quality diesel fuels are produced using hydro desulfurization process. Analysis of scientific publications has shown that the adsorption is effective method of desulphurization, which can serve as a method of removing SC from fuels or refining oil and its fractions, which allows removing residual sulfur. The advantages of the adsorption method are: low level of capital costs; simplicity of equipment; carrying out the process under much milder conditions compared to hydro desulfurization. In this paper, an original adsorption-catalytic method of reducing the concentration of SC to <10 ppm using a nanoporous adsorbent-catalyst is proposed. The structure and content of complex sulfur compounds in gas condensate fuels obtained from the raw materials of two deposits – Yamburgsky and Zapolyarny – were determined by gas chromatography–mass spectrometry. The next SC substances were found: tert-hexadecanethiol (C16H34S); 4,4,6-trimethyl-5-phenyl-1,3-oxazinane-2-thione (C13H17NOS); 1,2-bis(2-methylundecan-2-yl)-disulfane (C24H50S2); 3-methyl-2,4a,9,9a-tetrahydro-1H-2λ4-indeno [2,1-c]thiopyran-2-carbonitrile (C14H15NS) and 2,3,4,5-pentamethylbenzene-sulfoneamide (C11H17NO2S). Three-dimensional images of SC molecules and their adsorption complexes with Al-Ni-Mo-O component of a complex adsorbent-catalyst were obtained by molecular modeling. The adsorption energies of SC on the Al-Ni-Mo-O catalyst are calculated. The obtained values of the adsorption energies are in the range of −99.17 ÷−231.66 kJ/mol. As a result of the conducted research, a cartridge with selected adsorbent catalysts has been developed, which must be activated by heating in an inert medium up to 350 ° C. The average life of the cartridge is 1.5 years, after which it needs restoration.

Experimental Design of Oxidative Desulfurization of Kerosene Through Response Surface Methodology (RSM)

Sulfur compound content in fuels is one of the most undesirable pollutions regarding standard environmental regulations that demand to reduce sulfur concentration limit to 5-10% in fuels. Hence, kerosene’s oxidative desulfurization (ODS) as a model fuel (sulfur content 1158ppm) with air as an oxidant is studied. The goal of the study is to use two different synthesized nanosilica-supported catalysts, CuO/SiO2 (CAT-1) and CuO/TiO2-SiO2 (CAT-2), for the ODS of kerosene. Thirty-two experimental runs were designed via Central Composite Design (CCD) to select the experiments that will be utilized most efficiently. The analysis of variance (ANOVA) was used for statistical analysis to determine the models’ significance. The Response surface methodology (RSM) was used to determine the optimum conditions and parameters significantly affecting the response. Temperature and time are two variables studied due to their impact on oxidative desulfurization. The actual results of sulfur conversion in kerosene from lab experiments were 87% with a sulfur content of 153.3ppm and 99.22% with a sulfur content of 8.9ppm by CAT-1 and CAT-2, respectively, at conditions of 140°C and 100min. The predicted results from experimental design were 86.66% and 99.8% by CAT-1 and CAT-2 at conditions of 140°C and 100min, showing errors less than 3.1% and 1.2% for CAT-1 and CAT-2, respectively, from ANOVA. The optimal parameters of ODS were determined through the sulfur conversion maximization by numerical optimization via ANOVA. The results showed that the maximum conversion by CAT-1 was 99.5% at 140 min and 180°C, and by CAT-2 was 99.7% at 100.1 min and 140.1°C. Also, the rate data were fitted with an empirical kinetic model. The results showed that CAT-1 and CAT-2 activation energies were Ea= 28.2 kJ/mol and Ea= 38.7 kJ/mol, respectively.

PRODUCTION ENVIRONMENTALLY FRIENDLY DIESEL FUEL BASED ON DEAROMATIZED DIESEL FRACTION AND BUTYL ESTERS OF FATTY ACIDS OF SUNFLOWER OIL

Currently, special attention is paid to the environmental performance of fuels, because, the ever-increasing quantity of transport leads to an increase in the emission of harmful substances into the atmosphere. In particular, for the introduction of environmentally friendly technologies for the production of diesel fuels, first of all, it is necessary to obtain diesel fuel with a low content of sulfur, nitrogen and polycyclic aromatic compounds, which requires the processes of hydrotreating, hydrocracking and hydrodearomatization are carried out, which require significant economic costs. The presented article considers an alternative process for reducing the content of harmful substances, in particular aromatic compounds in the composition of diesel fuel. The process of dearomatization of the diesel fraction was carried out using N-methylpyrrolidone as an extractant at a ratio of extractant : diesel fraction 2:1 for 6 hours. The physicochemical properties of the dearomatized diesel fraction have been studied. In the resulting dearomatized diesel fraction, the sulfur content decreased to 0.0220%, and the content of aromatic compounds to 0%, in addition, the fractional composition is facilitated, the density and viscosity decrease. In order to replenish the resource of diesel fuel, oxygen-containing additives were added to the dearomatized diesel fraction - butyl esters of fatty acids of sunflower oil in an quantity of 5-10%, and the physicochemical properties of the resulting compounds were studied. It was revealed that the addition of butyl esters of fatty acids of sunflower oil to the composition of the dearomatized diesel fraction favorably affects the quality indicators of the obtained compounds. So, there is an increase in the flash point by 6°C and the cetane number by 4-5 points, and the sulfur content decreases to 0.0198%. In addition, the diameter of the wear scar decreases by about 2 times and for a 5% compound it is 0.430 mm, and for a 10% compound it is 0.370 mm, which meets the modern requirements of the standard. Thus, obtaining environmentally friendly diesel fuel is possible by dearomatization of the diesel fraction with the subsequent addition of butyl esters of fatty acids of sunflower oil, which can be recommended as a multifunctional additive to diesel fuels.

Synthesis of acrylamide-copper oxide hybrid structure as a novel photocatalyst for visible-light induced desulphurisation of petroleum diesel fuel

ABSTRACT Extreme reduction of sulphur compounds in diesel fuels is a crucial step during their production to help in protecting the environment from harmful emissions. Additionally, using a cost-effective process for such purpose is economically favourable. In agreement with these aspects, this study introduces production of low-sulphur diesel fuel through a photocatalytic route under effect of visible light. Hybrid structures made of combining polymerised acrylamide derivatives and copper oxide are presented as novel photocatalysts during this research work. Significant enhancements in the desulphurisation degrees by these photocatalysts could be achieved via using the acrylamide derivatives as polymers compared to their corresponding monomers. Notably, diesel fuel with a reduced sulphur content of exactly 2500 ppm, corresponds to 20 Wt. % of the original feedstock (12500 ppm), could be obtained by poly acrylamide/CuO composite. This content of sulphur compounds was further reduced to 440 ppm, referring to a total sulphur removal of 96.5%, via applying three successive photocatalytic stages at optimum operating conditions. The attainment of high percentages of desulphurisation by such composite is due to its content of electron donor atoms which enhanced overall photocatalytic performances.