High Sulfur Content Research Articles

Enhancing Fuel Properties of Napier Grass via Carbonization: A Comparison of Vapothermal and Hydrothermal Carbonization Treatments

Napier grass is a herbaceous biomass that can be used as biofuel; however, its high ash, potassium, sulfur and chlorine content may cause problems when combusted. Napier grass was submitted to vapothermal carbonization (VTC) and hydrothermal carbonization (HTC) processes at 190 and 220 °C to compare their ability to enhance its fuel properties. The different water distribution between phases in the two processes was verified: up to 14.5% of the water vaporized to steam in the VTC ran at 220 °C, while over 99% of the water remained in the liquid state and in contact with the solids during all HTC runs. Both processes improved the calorific value of the Napier grass (up to 20.6% for VTC220 and up to 29.8% for HTC220) due to the higher C content in the chars. Both processes reduced the sulfur content, removing up to 15.3% of it with VTC190 and 28.5% of it with HTC190 compared to that of Napier grass. In contrast, the two processes had different effects on the ash and chlorine content. While HTC removed both ash and Cl from the Napier grass, VTC concentrated it in the chars (ash: 5.6%wt. Napier grass, 3.3%wt. HTC chars, 7.1%wt. VTC; chlorine: 1.08%wt. Napier grass, 0.19%wt. HTC chars, 1.24%wt. VTC). Only the HTC process leached high percentages of Cl (up to 80%), S (up to 70%), sodium (Na, up to 80%) and potassium (K, up to 90%) into the process water. This may prevent fouling and slagging problems when burning HTC char. The biofuel qualities of the raw Napier grass, VTC, and HTC chars were evaluated using two standards: the international standard for solid biofuels, EN ISO 17225, and the Korean regulation for biomass solid recovered fuels (Bio-SRF). Napier grass and VTC chars presented problems regarding Cl content thresholds for both EN ISO 17225 and Bio-SRF. Both VTC and HTC chars along with the Napier grass fulfilled the requirements for heavy metals (Pb, Ni, Cr, and Cd) except for copper. The choice of process in practical applications will depend on the goal; HTC improves fuel quality and VTC has higher high solid, carbon and energy yields.

Discerning the sulfur geochemical features of turbidites and methane-rich sediments from the South China sea

Upward diffusion of dissolved methane and associated anaerobic oxidation of methane (AOM) coupled with microbial sulfate reduction (MSR) are widespread in normal hemipelagic sediments of continental margins. The occurrence of authigenic sulfur enrichment in such sediments is usually regarded as an indicator of AOM; however, extensive MSR and authigenic iron sulfide generation also occur in turbidites. Therefore, research attention should be directed toward determining the geochemical features of authigenic sulfur mineralization in methane-rich background sediments and turbidites. Here we report the sedimentology and geochemical composition of sediments from four piston cores (CL30, CL44, CL47, and CL3A) containing turbidite layers from methane-rich areas of the South China Sea. The turbidite layers were deposited at 17–15 kyr BP or earlier during the last glacial period and were located above the present sulfate–methane transition zone (SMTZ). The median grain size, proportion of sand-sized grains, and Si, Ti, K, and Zr contents show marked elevation in the turbidite layers compared with the background sediments, indicating the input of large amounts of terrigenous detrital matter with coarser grains. High total sulfur (TS) contents and low δ34SAIS values (AIS: acid-insoluble sulfur) (−35.2‰ to −26.1‰) are observed within turbidite layers relative to the background hemipelagic sediments in core CL44. These results suggest that intensive sulfidization occurred as a result of enhanced organoclastic sulfate reduction rates in turbidite horizons, which were probably caused by the resultant decrease in downward oxygen flux and waning bioturbation after rapid deposition of turbidites. In comparison, TS contents are higher and δ34SAIS values are positive (0.2‰–46.8‰) within the SMTZ on account of the rapid consumption of sulfate and build-up of isotopically heavier hydrogen sulfide pools via intensive AOM. Moreover, authigenic barium (Ba) enrichments commonly occur in the depth interval immediately above the SMTZ rather than within turbidite layers; therefore, they serve as a useful indicator of the position of the SMTZ. This study presents distinct differences in the geochemical compositions of turbidity deposits and methane-rich background sediments and highlights that a multi-proxy approach including sedimentological and geochemical analyses should be used to constrain the types of MSR in deep-sea sediments, given the common occurrence of turbidites and subsurface methane release in marginal deep-sea areas. It is also suggested that if applied with caution, S–C–Ba geochemical patterns can be used to identify palaeo-SMTZs and palaeo methane-rich zones in turbidite-containing strata.

Unraveling the rheology of inverse vulcanized polymers

Multiple relaxation times are used to capture the numerous stress relaxation modes found in bulk polymer melts. Herein, inverse vulcanization is used to synthesize high sulfur content (≥50 wt%) polymers that only need a single relaxation time to describe their stress relaxation. The S-S bonds in these organopolysulfides undergo dissociative bond exchange when exposed to elevated temperatures, making the bond exchange dominate the stress relaxation. Through the introduction of a dimeric norbornadiene crosslinker that improves thermomechanical properties, we show that it is possible for the Maxwell model of viscoelasticity to describe both dissociative covalent adaptable networks and living polymers, which is one of the few experimental realizations of a Maxwellian material. Rheological master curves utilizing time-temperature superposition were constructed using relaxation times as nonarbitrary horizontal shift factors. Despite advances in inverse vulcanization, this is the first complete characterization of the rheological properties of this class of unique polymeric material.

Ultrasonic pretreatment for enhancing flotation separation of elemental sulfur and silver-bearing lead minerals from an oxidative pressure leaching residue of zinc sulfide

Ultrasonic pretreatment was introduced to enhance the flotation separation of elemental sulfur and silver-bearing lead minerals from an ultrafine residue produced by oxidative pressure leaching of zinc sulfide. The particle size analysis of residue shows that ultrasonic pretreatment increases the number of particles with high sulfur content in the −19 μm fraction. This resulted from the associated sulfur was effectively liberated from other minerals. The complete liberation proportions of elemental sulfur and plumbojarosite in residue are respectively increased by 20.91 % and 38.53 % after ultrasonic treatment, in terms of mineral liberation analysis (MLA). Time-of-flight secondary ion mass spectrometry (ToF-SIMS) investigation implies that the surface structure difference between elemental sulfur and silver-bearing lead minerals is expanded by ultrasonic pretreatment. As a result, the separation of sulfur and silver-bearing lead minerals is significantly improved by ultrasonic pretreatment. Under optimized conditions of ultrasonic power, ultrasonic treatment time and solid weight, pilot-scale flotation produced a concentrate that the sulfur grade and recovery of concentrate increased by 11.63 % and 9.10 %, respectively, and the lead and silver recoveries of tailings increased by 8.72 % and 9.50 %, respectively, compared with those obtained by using the flotation without pretreatment. This work may provide an important reference for effectively recycling complex secondary resources and reducing the difficulty of subsequent values extraction.

Study on the Difference in Oxidation Characteristics of Coal and Gangue from the Same Coal Seam

ABSTRACT The gangue hills and underground backfill mining gob where crushed coal and coal gangue coexist face severe risks of spontaneous combustion. Studying the differences in oxidation characteristics between coal and gangue from the same coal seam is beneficial for spontaneous combustion. This paper tested the changes in radicals, functional groups, and gas products during the oxidation of raw coal, raw gangue, and washed gangue and analyzed their differences. Finally, gray correlation analysis was used to calculate the correlation between active groups and gas. The results showed that raw coal contained a more significant initial radical concentration and g factor value than raw and washed gangue. Its aliphatic hydrocarbons and oxygen-containing functional groups content was also significantly higher. The growth rate of radical concentration in the early oxidation stage of washed gangue was larger than that of raw coal and raw gangue due to the high sulfur content. At the same time, the temperature at which the g factor started to increase rapidly and the temperature at which the aliphatic hydrocarbons decreased rapidly was lower than that of raw coal and raw gangue. Gray correlation analysis showed that the active groups closely related to oxygen consumption were CH3 and CH2, while the groups closely associated with CO generation were C=O, COOH, Ng, and g factor.

Processable crosslinked terpolymers made from elemental sulfur with wide range of thermal and mechanical properties

Inverse vulcanization has emerged as a popular strategy for transforming the waste material, elemental sulfur, into functional polymers with high sulfur content (>50 wt.%, normally). Inverse vulcanized polymers are intrinsically processable and recyclable, and have been demonstrated as promising for applications in many fields. However, the mechanical properties of inverse vulcanized polymers are currently underdeveloped. If this kind of material is to be widely used in some scenarios to replace some traditional plastics, it is necessary to make them with appropriate thermal and mechanical properties that meet basic application requirements. Here, we report a series of terpolymers copolymerized from two distinct organic comonomers and elemental sulfur to obtain polymers with a wide range of glass transition temperatures (−43 °C to 45 °C) that exhibit good mechanical properties, by blending crosslinkers with varying feed monomer ratio and chain length of linear sections, which expands the application opportunities of inverse vulcanization.

Preparation of a single metal catalyst loaded on alumina support to refine waste tire pyrolysis oil (WTPO) via catalytic hydrogenation

Improper disposal of industrial waste, particularly non-biodegradable solid waste like waste tires, has long been a significant environmental concern. Despite this, waste tires can be converted to fuel as alternative source through pyrolysis. However, waste tire pyrolysis oil (WTPO) has limitations, such as high sulfur content, making it unsuitable for direct use as a fuel. This research aims to improve the quality of waste tire pyrolysis oil (WTPO) by catalytic hydrogenation. Using modified metal catalysts, including nickel, cobalt, ammonium molybdenum, and alumina as supporting substances. The catalyst was synthesized using the impregnation method and subsequently subjected to calcination. The catalyst performance was evaluated by conducting the hydrogenation reaction. The catalytic hydrogenation reaction results indicate that the catalyst Mo/Al2O3 exhibited the best performance in producing refined oil. The refined oil was desulfurized to a sulfur compound of 0.7 wt% at 320 °C under the flow rate of the gas of 100 ± 50 cm3/min, which corresponded to a sulfur reduction of 75% compared to the initial feedstock. Interestingly, while the non-catalytic reaction presented the highest performance towards sulfur removal of 80%, it was inferior towards the selectivity of benzene, D-limone and p-cymene.

Comparative assessment of the qualities of commercial and synthetic transformer oils

Petroleum transformer oils previously produced in the USSR met the requirements of ГОСТ 982-80. Balakhany oil and Dossor low-paraffin oil of the Emben field were the raw materials for obtaining transformer oil. The composition of transformer oils is taken into account when choosing raw materials and their regeneration. Т-1500у – transformer oil of improved quality, is used in electrical equipment up to 500 kV and up to 750 kV. ГК oil is a hydrocracking transformer oil, used in voltages up to 1150 kV, contains ionol. Тсп is oil from West Siberian oils, used up to 220 kV. This oil is of relatively low quality, characterized by a high sulfur content, low oxidation stability, and high dielectric loss tg. In the Institute of Petrochemical Processes, research has been carried out on the selective purification of transformer oil distillate from Balakhany oil using a new highly effective solvent – ionic liquid (IL) – a quaternary ammonium salt of formic acid and a number of amines – morpholine, aniline or di-, triethylamines. The optimal conditions for the selective purification of the distillate have been developed. Due to the shortage of high-quality transformer oils, as well as the high cost, in recent years, oils have been imported from Sweden and Austria. An ionic liquid as a solvent is highly selective and selective. The analysis of the extract from selective purification showed that it does not contain naphthene-paraffins, the content of aromatic hydrocarbons in the extract is 65 %, and when purified with furfural it is 40.8 %. The ionic liquid is environmentally friendly.

3D printing of hierarchically porous lightweight activated carbon/alumina monolithic adsorbent for adsorptive desulfurization of hydrogenated diesel

Hierarchically porous materials have shown extensive applications in the domain of adsorbing environmental contaminants. Herein, a novel approach utilizing a 3D printing-freeze-drying strategy was presented to successfully design a hierarchically porous lightweight three-dimensional activated carbon/alumina (3D-AC/Al2O3) monolithic adsorbent for adsorptive desulfurization of hydrogenated diesel. 3D-AC/Al2O3 monolithic adsorbents can exhibit superior adsorptive desulfurization performance at room temperature, as well as good cycling performance, thermal and mechanical stability. With incorporating designed 3D-printed liquid redistributor to enhance mass transfer within fixed bed, 3D-AC/Al2O3 can achieve 96.6 % sulfur removal with the sulfur adsorption capacity of 10.13 mg-S/g-Ads for feed oil of high initial sulfur content. Benefited from the hierarchical porous structure to form micron-millimeter scale adsorption micro-channel, feed oil can enter the interior of the monolithic adsorbents and fully contact with the adsorptive active sites to enhance the mass transfer. Furthermore, through the design of the “adsorption-elution” reaction process, it becomes possible to accomplish both the removal of sulfides from feed oil through adsorption and the recovery of value-added sulfides that adsorbed onto the adsorbents. This simultaneous achievement highlights the practical potential for application in this context. Notably, the integrated 3D-AC/Al2O3 adsorbent exhibited promising desulfurization effects for application of real hydrogenated diesel.

Extremely 13C-enriched dolomite records interval of strong methanogenesis following a sulfate decline in the Miocene Ries impact crater lake

In impact crater lakes, the lacustrine sedimentary records may not solely reflect climatic changes but also potential erosional effects from lithologically distinct impactite formations. The hydrochemical and biogeochemical processes during the deposition of the Nördlinger Ries impact crater lake, which fall in the range of the mid-Miocene Climate Transition, were studied by analysing microcrystalline authigenic carbonates in a drill core succession, using stable oxygen and carbon isotopes in conjunction with biomarkers. These investigations revealed an early sulfidic interval characterized by thiophenes, iso- and anteiso-C15:0 acids derived from sulfate reducing bacteria, and dolomites with low to intermediate δ13Ccarb values. The subsequent distinctive interval is characterized by extremely 13C-enriched dolomite (δ13Ccarb up to +20.93 ± 0.05‰ V-PDB), decline of iso- and anteiso-C15:0 acids and is rich in an Archaea-derived archaeol that is 13C-enriched (−14.7‰), indicating extensive methanogenesis in sulfate-depleted lake porewater during early diagenesis. The sulfate decline results from successive sulfate reduction when replenishment by sulfate-bearing inflow water is limited. The carbonates exhibit enriched 18O due to pronounced evaporation in a long-resided water body and enriched 13C by methanogenesis. A change in provenance of water derived from the sulfur-rich suevite (impact melt-bearing breccia) and crystalline source rocks to the sulfur-poor Bunte Breccia (continuous ejecta blanket) is required. Intermittently high Si/Al and Zr/Al at the high δ13C interval suggests sporadic short-term runoff increase, leading to fluctuating physiochemical lake conditions. A subsequent decline in both δ13Ccarb and archaeol indicates a decreasing lake level with intermittent subaerial exposure events, supported by bioturbation and mud cracks. The concomitant lake oxygenation is well supported by increasing Pr/Ph ratios and lipids derived from aerobic methanotrophs (13C-depleted 3-methyl-hopanoids). In the youngest unit, allochthonous lignites and biomarkers from lacustrine/soil sources appear, high total sulphur contents and thiophenes recur, and stable C and O isotope values decrease again. These observations suggest another major provenance change of the inflowing solutes, with increasing influx from weathered pyrite-bearing Jurassic claystones. These findings demonstrate that the climatic record expected from the stable carbon and oxygen isotopes of the Ries carbonates is strongly overprinted by hydrochemical and biogeochemical processes due to changing ion influx from substrate rocks, along the course of the successive ejecta erosion and catchment changes. Such an intrinsic control of lacustrine biogeochemical processes is also expected for other hydrologically closed impact crater lake basins, where catchment rocks with distinctively different lithologies are present.

Milk Thistle (Silybum marianum (L.) Gaertner) Endosperm as an Alternative Protein Source for a Sustainable Food System (SFS)—Pilot Studies

Milk thistle is a plant that perfectly meets the needs of sustainable agriculture. Despite their high protein content, the seeds and endosperm of S. marianum have not been considered as raw food material so far. Therefore, the work aimed to characterize milk thistle endosperm in terms of its possible use in producing novel food. The nutritional and energy value of the raw material, profile of amino acids), fatty acids, and health quality indices of lipids were characterized. The main components of milk thistle endosperm (MTE) were protein (>20% dry matter (DM)), fat (>39% DM), and fiber (>31% DM). MTE protein is characterized by a high content of sulfur, aromatic amino acids, and tryptophan, comparing the FAO/WHO patterns. The PDCAA S (Protein Digestibility Corrected Amino Acid Score) value for lysine is low but can be higher in combination with other proteins. Milk thistle fat is dominated by unsaturated fatty acids, constituting about 80% of total fatty acids, of which over 56% are polyunsaturated fatty acids. Low values of atherogenicity and thrombogenicity indices of MTE fat testify to its potentially beneficial properties towards the cardiovascular system.

Upgrading MSW pyrolysis oil through distillation and hydrotreatment for automobile engine applications: A short review

The demand for fossil fuel in today’s world is increasing at a higher pace with rapid population growth and industrial development. The reserve for petroleum-based fossil fuels is finite which necessitates the search for alternative fuels. Pyrolysis oil obtained from Municipal Solid Waste (MSW) has drawn the attention of many researchers because of their high heating value and similar fuel properties with commercial automobile fuel and has potential to substitute commercial diesel fuel. Nevertheless, the crude oil obtained from pyrolysis of MSW has some shortcomings such as higher viscosity and density, lower flash point and cetane index, unpleasant odor, and higher sulfur content, preventing its useability as a drop in fuel for automobiles at present. In this short review, distillation and hydrotreatment post treatment procedures, amongst many others, are discussed for improving the properties of pyrolysis crude oil. Focus has been given on waste plastic and waste automobile tire pyrolysis oils as they constitute a significant amount of MSW currently. This review reported that noticeable improvement of the properties (cetane number, flash point, viscosity, and sulphur contents) of crude pyrolysis oil (PPO or TPO) can be achieved through distillation and/or hydrotreatment, which are comparable to the properties of standard diesel.

Effect of Adding Cu2O as a Back Surface Field Layer on the Performance of Copper Manganese Tin Sulfide Solar Cells

One of the major limitations causing deadlock in solar cells with higher sulfur content in the photovoltaic absorber material is the unintended formation of an uncontrollable MoS2 layer between the absorber material and Mo back contact, which can affect negatively the efficiency of solar cells. Researchers reported that it is very difficult to control the MoS2 properties such as the conductivity type, thickness, band gap, and carrier concentration in experiments. Considering these challenges, an initial step involved a thorough examination utilizing the one-dimensional solar cell capacitance simulator (SCAPS-1D) to assess the impact of n-MoS2 interlayer thickness and donor concentration on the performance of CMTS solar cells. Our investigation revealed the formation of a “cliff-like CBO” at the CMTS/n-MoS2 interface, facilitating the transport of electrons from the p-CMTS absorber to the Mo back contact, resulting in a significantly higher recombination rate. Subsequently, herein a novel approach is proposed, using Cu2O as a back surface field (BSF) layer due to its low cost, intrinsic p-type properties, and non-toxic nature. Simulation results of a novel heterostructure (Mo/Cu2O/CMTS/CdS/i-ZnO/AZO/Al) of the CMTS-based solar cell are discussed in terms of recombination rate and conduction band alignment at the absorber/BSF interface. A desired “spike-like CBO” is formed between CMTS/Cu2O, which hinders the transport of electrons to the back contact. By optimizing the physical parameters such as thickness and the doping density of the Cu2O layer, an efficiency η of 21.78% is achieved, with an open circuit voltage (Voc) of 1.26 V, short-circuit current density (Jsc) of 24.45 mA/cm², and fill factor (FF) of 70.85%. Our simulation results offer a promising research direction to further develop highly efficient and low-cost CMTS solar cells.

Effect of trace sulfur on the hot corrosion resistance of Ni-base single crystal superalloy

The effect of sulfur on the hot corrosion resistance of Ni-base single crystal superalloy was investigated in Na2SO4 salt at 900 °C in static air. The results indicate that the corrosion resistance of the superalloy is significantly degraded even with several ppm contents of sulfur in the alloy. High sulfur content in the alloy causes the oxide layer to bulge and significantly shortens the corrosion incubation period. The accelerated corrosion process is attributed to the outward diffusion of sulfur from the alloy promoting S segregation at the oxide/metal interface and hence favors crack premature initiation.

Biodesulfurization of Fossil Fuels: Analysis and Prospective.

Biodesulfurization (BDS) of fossil fuels is a promising method for treating the high content of sulfur in crude oils and their derivatives in the future, attributed to its environmental-friendly nature and the technical efficient ability to desulfurize the organosulfur compounds recalcitrant on other techniques. It was found that the bioreaction rate depends on the treated fluid, targeting sulfur compounds, and the microorganism applied. Also, many studies investigated the operation conditions, specificity, and biocatalysts modification to develop BDS efficiency. Furthermore, mathematical kinetics models were formulated to represent the process. In this review, the previous studies are analyzed and discussed. This review article is characterized by a clear picture of all BDS's experimental, industrial, procedural, theoretical, and hypothetical points.

Integration and optimization of the after-treatments systems to reduce the acoustic footprint of the ships

Exhaust Gas Cleaning Systems (EGCS) such as scrubbers are mandatory and extensively used to abate SOx in exhaust gases when high sulphur content fuel oil is employed in the marine engine in order to comply with international ship emission regulations, both in new and existing ships. Currently, about 13% of bulker, container, and tanker ships have a scrubber installed, despite the fact that their installation on board is challenging due to their large dimensions to be fitted into the funnel and the complexity of the system, since the exhaust line must control both the chemical and acoustic emissions. In the presented work a combined FEM, CFD simulations and GA optimization methodology aimed at the integration of the abatement system, while optimizing the acoustic properties, is developed. The methodology is first assessed on an industrially-relevant scenario that involves the use of a Genset mock-up equipped with a reference Diesel Oxidation Catalyst (DOC) and a scrubber for the abatement of both NOx and SOx, showing that acoustic performances of the DOC are reliably modelled by the FEM-CFD methodology, which has a significantly reduced computational cost as compared to conventional CFD modelling of acoustic properties. The GA optimization is carried out to improve the DOC acoustic properties showing that it is possible to confer the silencing effect to the after-treatment systems, thus eliminating the traditional silencers from the exhaust line. This leads to a compact exhaust line that integrates the EGCS while maintaining efficient both the chemical pollution abatement capability, and silencing effects to guarantee full compliance (i.e., acoustic and chemical) with the international regulations.

Sulfur and Cystine Content in Various Sheep Wool Breeds and Their Correlation with Wool Growth and Strength

This scholarly article presents a comprehensive analysis of sulfur and cystine content in the wool of various sheep breeds, with a particular focus on their relationship with wool growth and strength. The breeds under scrutiny include the Askanian fine-wool, Prekos, Latvian dark-headed, Ukrainian Carpathian mountain, and Karakul breeds. Our research revolves around wool samples extracted from the scapula area before the spring shearing process. Our findings reveal that the highest sulfur content is observed in the wool of Karakul sheep (3.05 %) and Prekos sheep (2.90 %), whereas the lowest sulfur content is noted in Latvian dark-headed sheep (2.65 %). Conversely, the highest cystine content is exhibited in the wool of Askanian fine-wool sheep (11.87 %) and Prekos sheep (11.46 %), while the lowest cystine content characterizes the wool of Karakul sheep (8.99 %) and the Latvian dark-headed breed (10.10 %). The genetic factors, specifically breed-specific characteristics, impact on the rate of wool growth. The most rapid growth rates are observed in Karakul sheep (873 mg/cm/day) and Askanian fine-wool sheep (857 mg/cm/day). Slightly lower growth rates are noted in Prekos breed sheep (844 mg/cm/day) and Ukrainian Carpathian mountain breed sheep (766 mg/cm/day). The lowest growth rates are recorded in Latvian dark-headed sheep (742 mg/cm/day). Furthermore, we establish that the highest tensile strength values are associated with the coarse wool of Karakul sheep (9.6 cN/tex) and the semi-coarse wool of Ukrainian Carpathian mountain sheep (9.3 cN/tex), as these fibers possess the thickest cuticular layer. Conversely, the lowest tensile strength values are observed in the wool of Latvian dark-headed sheep (7.0 cN/tex) and Prekos breed (7.1 cN/tex). An examination of the data reveals that there is no statistically significant correlation between the content of sulfur and cystine and the rate of wool growth. However, a robust direct correlational relationship is identified between the sulfur content and fiber strength (with correlation coefficients of r = 0.831 for Karakul breed sheep wool, 0.713 for Latvian dark-headed, 0.698 for Ukrainian Carpathian mountain, 0.544 for Askanian fine-wool, and 0.460 for Prekos breed wool).

Synthesis of POM@Porphyrin COF heterogeneous catalyst for oxidative desulfurization of thio compounds

Sulfur compounds cause substantial environmental pollution problems, and their immediate removal is urgently needed to keep the environment clean. Fuel desulfurization is necessary due to the severe impacts of sulfur on humans, wildlife, and crops when emitted into the atmosphere during fuel combustion. Fuels with high sulfur contents used in automobiles and factories are the primary source of atmospheric sulfur. A new covalent organic framework (COF) MnTP@ZnAdCOF [(N(C4H9)4]12[{NHC(CH2O)3}4(CO)4C44H24N4Mn(OCOCH3)][ZnMo6O18]4 is synthesized and characterized thoroughly using FT-IR, UV/visible, 1HNMR, TGA, PXRD, SEM-EDX, cyclic voltammetry and fluorescence spectroscopy. Herein, an environmentally safe and cost-effective approach for the ODS of thiobenzoic acid is reported using H2O2 as an oxidant and MnTP@ZnAdCOF as a heterogenous catalyst under mild reaction conditions. Desulphurization results of the catalyst are confirmed by the RP-HPLC technique using acetonitrile and water in a 50:50 M ratio as a mobile phase. Active intermediates [(Por)(OAc)Mn-OOH]−, [(Por)(OAc)MnIVO] and Mo(O2) are formed due to oxidation of Mn and Mo metal in the presence of H2O2 considered responsible for the excellent catalytic efficiency of MnTP@ZnAdCOF catalyst up to 98% desulphurization efficiency was observed. Incredible catalytic conversion of dibenzothiophene, thiobenzoic acid and the mixture of different Sulphur containing compounds to sulfoxide is observed at 25 ℃ temperature. The H2O2/S molar ratio of 5:1 is an outstanding achievement that can be utilized for the oxidation of sulfur compounds present in diesel to reduce the sulfur contents of fuel.

Numerical simulation of pulverized coal combustion in a 660MW tangentially fired boiler with fuel variation

To study the effects of various coal properties on the combustion characteristics during actual operation, and on the high temperature corrosion of the water wall. The paper presents a numerical simulation of a 660MW boiler using ANSYS FLUENT software. Three cases were investigated with various fuel properties: (1) the designed coal NO.1, (2) the non-designed coal NO.2 with high ash, high sulphur content and low volatile matter, (3) the blended fuel of coal NO.3with similar coal quality to the coal NO.1 and NO.4 with high sulphur content. Simulation results indicate that blended coal feeding can improve the combustion characteristics of poor-quality coals. It provides a theoretical reference for the actual operation of power plants with non-designed coals.

Strong succession in prokaryotic association networks and community assembly mechanisms in an acid mine drainage-impacted riverine ecosystem.

Acid mine drainage (AMD) serves as an ideal model system for investigating microbial ecology, interaction, and assembly mechanism in natural environments. While previous studies have explored the structure and function of microbial communities in AMD, the succession patterns of microbial association networks and underlying assembly mechanisms during natural attenuation processes remain elusive. Here, we investigated prokaryotic microbial diversity and community assembly along an AMD-impacted river, from the extremely acidic, heavily polluted headwaters to the nearly neutral downstream sites. Microbial diversity was increased along the river, and microbial community composition shifted from acidophile-dominated to freshwater taxa-dominated communities. The complexity and relative modularity of the microbial networks were also increased, indicating greater network stability during succession. Deterministic processes, including abiotic selection of pH and high contents of sulfur and iron, governed community assembly in the headwaters. Although the stochasticity ratio was increased downstream, manganese content, microbial negative cohesion, and relative modularity played important roles in shaping microbial community structure. Overall, this study provides valuable insights into the ecological processes that govern microbial community succession in AMD-impacted riverine ecosystems. These findings have important implications for in-situ remediation of AMD contamination.