Reduction Of Sulfur Content Research Articles

Reduction in sulfur content of electrodeposited bulk nanocrystalline Fe–Ni alloys using manganese chloride

A method for reducing the sulfur content of electrodeposited bulk nanocrystalline Fe–Ni alloys was developed to improve the tensile ductility of the materials and prevent thermal embrittlement caused by the grain boundary segregation of sulfur. Bulk nanocrystalline Fe–Ni alloys were prepared using electrolytes that primarily consisted of iron sulfate and nickel sulfamate combined with manganese chloride (MnCl2). The addition of MnCl2 in the deposition bath did not produce any significant changes in the Ni content and grain sizes of the electrodeposited alloys. In contrast, the sulfur content in the materials decreased from 840 to 620atppm. The bulk nanocrystalline Fe–Ni alloys with low sulfur content exhibited a higher tensile elongation of 16–19% compared to the materials with high sulfur content. Furthermore, after annealing at 200°C for 3h, The bulk nanocrystalline Fe–Ni alloys with low sulfur content exhibited a high tensile elongation of 9–10%, whereas the elongation of the materials with high sulfur content was 3%. The results indicate that the plastic elongation of electrodeposited bulk nanocrystalline Fe–Ni alloys can be improved by reducing the amount of sulfur in the materials.

Effects of extreme experimental drought and rewetting on CO2 and CH4 exchange in mesocosms of 14 European peatlands with different nitrogen and sulfur deposition

The quantitative impact of intense drought and rewetting on gas exchange in ombrotrophic bogs is still uncertain. In particular, we lack studies investigating multitudes of sites with different soil properties and nitrogen (N) and sulfur (S) deposition under consistent environmental conditions. We explored the timing and magnitude of change in CO2 (Respiration, Gross Primary Production - GPP, and Net Exchange - NE) and CH4 fluxes during an initial wet, a prolonged dry (~100days), and a subsequent wet period (~230days) at 12°C in 14 Sphagnum peat mesocosms collected in hollows from bogs in the UK, Ireland, Poland, and Slovakia. The relationship of N and S deposition with GPP, respiration, and CH4 exchange was investigated. Nitrogen deposition increased CO2 fluxes and GPP more than respiration, at least up to about 15kg N ha(-1) yr(-1) . All mesocosms became CO2 sources during drying and most of them when the entire annual period was considered. Response of GPP to drying was faster than that of respiration and contributed more to the change in NE; the effect was persistent and few sites recovered "predry" GPP by the end of the wet phase. Respiration was higher during the dry phase, but did not keep increasing as WT kept falling and peaked within the initial 33days of drying; the change was larger when differences in humification with depth were small. CH4 fluxes strongly peaked during early drought and water table decline. After rewetting, methanogenesis recovered faster in dense peats, but CH4 fluxes remained low for several months, especially in peats with higher inorganic reduced sulfur content, where sulfate was generated and methanogenesis remained suppressed. Based on a range of European sites, the results support the idea that N and S deposition and intense drought can substantially affect greenhouse gas exchange on the annual scale.

Mechanisms of Oxidative Desulfurization of Straight-Run Residual Fuel Oil Using Ozonized Air

The possibility of reducing sulfur content of Astrakhan gas condensate in residual fuel oil by oxidative desulfurization using ozonized air is examined. The optimal conditions for oxidizing with ozone and for thermal decomposition of oxidized sulfur compounds are determined. The sulfur content in residual fuel oil can be reduced from 2.86 to 0.48 wt. %, whereupon hydrogen sulfide is removed completely from the residual fuel oil and the combustion heat increases.

Mycobiota of Oil-Contaminated Soil Samples and Their Abilities for Dibenzothiophene Desulfurization

ABSTRACTHigh sulfur content of crude oil leads to poor quality of oil products and many other negative consequences such as corrosion, catalyst poisoning and environmental pollution. Saudi Arabia is seeking to reduce sulfur content in diesel and gasoline to 10 ppm and to lower benzene content in gasoline to 1%. Biotechnological processes such as biodesulfurization can be considered an alternative or complement to conventional oil refining technologies. So, the objective of the present project is to isolate and identify endogenous fungal isolates capable of oil biodesulfurization. From 60 oil-contaminated soil samples collected from Saudi Arabia, 15 species belonged to 9 fungal genera were collected and identified morphologically and with ITS sequencing. Members of Aspergillus, Penicillium and Fusarium were the most prevalent in the investigated samples. Among the collected fungal species, only Stachybotrys bisbyiisolates were able to utilize dibenzothiophene (DBT) as the sole sulfur source. Stachybotrys bisbyi TUSb1 could desulfurize 99% of the DBT (0.3 mM) as the sulfur source by a co-metabolism reaction with other carbon sources through the same pathway as 4S (involves sequential oxidation of the sulfur part and cleaving of the C–S bonds), and produced 2-hydroxy biphenyl (2-HBP) during 7 days of incubation at 30°C and 180 rpm. Stachybotrys bisbyi TUSb1 showed broad specificity for removing sulfur in different sulfur-containing compounds.

Impacts of nickel supported on different zeolites on waste tire-derived oil and formation of some petrochemicals

Waste tire-derived oils commonly contain the considerable valuable aromatics such as benzene, toluene, ethylbenzene, toluene, xylenes and etc., but they also contain a significantly-high amount of sulfur compounds, which cause a low quality of pyrolytic oil. Ni is a cheap metal, which exhibits hydrogenation/dehydrogenation and ring-opening like a noble metal, and widely used as promoter in desulfurization of fuels. In this work, Ni was expected to be a catalyst promoter of zeolites for reduction of sulfur content in oil and enhancement of petrochemical formation in oil. Therefore, the effect of 5wt.% nickel loading on different four type zeolites (HZSM-5, HMOR, HY, HBETA) on the sulfur removal and quality of waste-tire derived oil was studied. The results show that the incorporations of nickel on all zeolites significantly reduced sulfur contents in oil. However, the quality of waste tire-derived oil did not only depend on the nickel promoter, but also strongly depended on zeolite supports. The introduction of nickel on HZSM-5 zeolite, which possesses a smaller pore size than HBETA zeolites, provided a lighter oil with higher proportion of gasoline and kerosene than Ni/HBETA catalyst, and produced a higher amounts of valuable aromatic such as ethylbenzene, toluene, cumene, and mixed-xylenes than Ni/HBETA catalyst. Moreover, the addition of nickel on HMOR zeolite, which possesses a 1D zeolite channel structure, also provided a lighter oil with a high proportion of gasoline and kerosene than the Ni-loaded on HBETA (3D zeolite channel structure), and exhibited a better petrochemical production with a higher concentrations of ethylbenzene, toluene, cumene and styrene in maltene. On the other hand, Ni/HBETA provided the lower sulfur content in oil than Ni/HMOR catalyst, but the sulfur removal ability by nickel species on HMOR was higher than nickel species on HBETA zeolite. Furthermore, the introduction of nickel on HY zeolite provided the heavier oil with higher proportion of gas oil, LVGO and HVGO and lower proportion of petrochemical than Ni/HBETA zeolite whereas the sulfur removal of nickel species on the HBETA support with higher acid strength was better than on the HY support.

Evaluation of Emitted Particulate Matters Emissions in Multi-cylinder Diesel Engine Fuelled with Biodiesel

As an alternative fuel, biodiesel is receiving rising attention for diesel engines. The corn oil biodiesel was prepared from Iraqi produced corn oil through transesterification process, using methanol and sodium hydroxide in the present investigation. Neat corn oil biodiesel, as well as, the blends of varying proportions of it and diesel was used to run a 4-cylinders direct injection CI engine. The effects of some engine variables like load, speed, and injection timing on emitted particulate matters (PM) were studied. The aim was to evaluate the emitted particulate matters from a diesel engine when it fuelled with blends diesel and biodiesel. As the Iraqi conventional diesel has high sulfur content that release high rates of PM, it was taking as the baseline fuel in the tests. The results showed a significant reduction in PM when biodiesel was used. The maximum reductions in PM concentrations observed were 34.96 % in the case of biodiesel operation compared to diesel at full engine loads and constant speed. An increment in the PM concentrations as the timing retarded from the optimum injection timing. Biodiesel has a significant impact on smoke at idle mode with reductions of 8.6%, 18%, and 39.75% for B20, B50, and B100 respectively compared to diesel. The study concludes the possibility of more reduction of PM concentrations in the case of reducing sulfur content in Iraqi diesel fuel significantly.

Mechanical Properties of Welded Joint at Cryogenic Temperature for Manufacturing of ITER TF Coil Structure

The ITER toroidal field (TF) coil structure is a huge welding stainless steel structure with a height of 16 m and a width of 9 m. The TF coil structure has a function to ensure the enormous electromagnetic force, whereas in ITER operation temperature (4 K). FMYJJ1, which is full austenitic stainless steel welding material having high manganese contents, is applied for manufacturing TF coil structure. However, it was reported that some micro cracks were observed on the reheating zone in the thicker welded joint during trials. Low ductility of deposited metal at 1000 °C causes these microcracks. In addition, segregation of sulfur in grain boundary decreased ductility at high temperature. Hence, reducing sulfur content is effective to reduce microcracks. Two types of FMYJJ1 were developed by applying two reducing sulfur content methods. In the previous study, applicability of these improved FMYJJ1 was tested within welded joints having 20-mm thickness. In order to confirm the validity of applicability of them, the Japan Atomic Energy Agency manufactured welded joints with 200-mm thickness, which is the representative thickness of the TF coil structure. When ductility is increased, there is a concern that yield strength is decreased. Hence, confirmation of the mechanical properties is needed. Therefore, side bend test, tensile test, and fracture toughness test at 4 K were performed. As the result, it was confirmed that the crack sensitivity was improved, and it was also confirmed that mechanical properties at 4 K satisfied ITER design requirements.

Reduction of Sulphur Content of AGBAJA Iron Ore Using Sulphuric Acid (H2SO4)

Iron ores are used in blast furnace for the production of pig iron; AGBAJA Iron ore has an estimated reserve of over I billion metric tonnes. Unfortunately, this large reserve cannot be utilized for the production of pig iron due to its high sulphur contents. This work studied the reduction of sulphur content of AGBAJA iron ore. Acid leaching methods were used to reduce sulphur contents of the ore sulphuric acid of different concentrations were used at various leaching times, acid concentrations and particle sizes. Atomic Absorption Spectrophotometer, X-ray fluorescence spectrophotometer, Digital muffle furnace and Absorbance-concentration technique were used for experimentation and chemical analysis. The reduction of the sulphur content of AGBAJA Iron Ore using Acid leaching process experiments were carried out at the National Metallurgical Development Centre (NMDC), Jos in Plateau State of Nigeria. Sulphur is one of the main harmful elements in ferrous metallurgy and it affects the quality of iron and steel produced. At present, Nigeria has some large iron ore deposits including AGBAJA which bear tremendous iron ore with high sulphur content of 0.12%. Central composite design technique was applied to obtain optimum conditions of the processes. Surface response plots were also obtained. The percentage degrees of reduction of sulphur content of AGBAJA Iron ore were found to increase with increase in acid concentration and leaching time and a decrease in particle size for the three acids. The experimental results for percentage removal of sulphur are 87.77% the optimum % removal of sulphur is 87.73%. The result of this work has shown that AGBAJA Iron Ore if properly processed can be used in our metallurgical plants and also can be exported since sulphur contents of the ore have been reduced drastically.

Reduction of Sulphur Content of AGBAJA Iron Ore using Hydrochloric Acid (HCL)

Iron ores are used in blast furnace for the production of pig iron; AGBAJA Iron ore has an estimated reserve of over I billion metric tonnes. Unfortunately, this large reserve cannot be utilized for the production of pig iron due to its high sulphur contents. This work studied the reduction of sulphur content of AGBAJA iron ore. Acid leaching methods were used to reduce sulphur contents of the ore. Sulphuric acid of different concentrations were used at various leaching times, acid concentrations and particle sizes. Atomic Absorption Spectrophotometer, X-ray fluorescence spectrophotometer, Digital muffle furnace and Absorbance-concentration technique were used for experimentation and chemical analysis. The reduction of the sulphur content of AGBAJA Iron Ore using Acid leaching process experiments were carried out at the National Metallurgical Development Centre (NMDC), Jos in Plateau State of Nigeria. Sulphur is one of the main harmful elements in ferrous metallurgy and it affects the quality of iron and steel produced. At present, Nigeria has some large iron ore deposits including AGBAJA which bear tremendous iron ore with high sulphur content of 0.12%. Central composite design technique was applied to obtain optimum conditions of the processes. Surface response plots were obtained. The percentage degrees of reduction of sulphur content of AGBAJA Iron ore were found to increase with increase in acid concentration and leaching time and a decrease in particle size for the three acids. The experimental results for percentage removal of sulphur are 85.56% the optimum % removal of sulphur is 89.66%. The result of this work has shown that AGBAJA Iron Ore if properly processed can be used in our metallurgical plants and also can be exported since sulphur contents of the ore have been reduced drastically.

ChemInform Abstract: Surface Science Approaches for the Preparation of Alumina‐Supported Hydrotreating Catalysts

AbstractReview: 158 refs.

Deep HDS of FCC gasoline over alumina supported CoMoS catalyst: Inhibiting effects of carbon monoxide and water

The selective hydrodesulfurization (HDS) of FCC gasoline is a key catalytic process for reducing sulfur content in gasoline. In the present work, we focus on the effect of H2O amount alone or in mixture with CO on the transformation of a model FCC gasoline composed of 2-methylthiophene (2MT) and 2,3-dimethylbut-2-ene (23DMB2N) molecules, over an alumina supported CoMoS catalyst. A negative impact of water and CO on the conversion of 2MT and 23DMB2N is found. However the effect in the presence of CO is much stronger. The comparison of Density Functional Theory (DFT) calculations of CO and water adsorption on the S- and M-edge sites of the CoMoS slabs shows a significantly stronger CO adsorption energy than water adsorption energy. When CO and water were introduced simultaneously, the negative impact observed in the transformation of the model feed is mainly due only to the presence of CO. However whatever the oxygenated molecules used and their amount, no impact in the selectivity measured by the ratio between the activity in hydrodesulfurization and in hydrogenation is observed.

Surface Science Approaches for the Preparation of Alumina‐Supported Hydrotreating Catalysts

AbstractNew developments and breakthroughs in the design of hydrotreating (HDT) catalysts for complying with fuel specifications and reduced sulfur contents ask for a continuous improvement in the molecular scale description of the active phase both at the oxide and sulfide states. HDT catalysts are mainly based on alumina‐supported molybdenum nanophases and the present contribution is dedicated to review the surface science approaches that have helped gain a molecular‐scale insight into the structure of the active‐phase (mainly molybdenum) and the role of metal‐support (mainly alumina) interactions through the use of well‐defined surfaces and surface sensitive analysis techniques. The main focus of this Review is placed on model systems that can bridge the gap with industrial catalysts, that is, oxide‐supported active phases prepared in aqueous conditions, as opposed to more traditional surface‐science studies that consider metal‐supported nanophases prepared in UHV conditions. The synthesis and structure of well‐defined alumina surfaces (thin films and single crystal wafers) is first presented before discussing aqueous‐deposition of Mo precursors on flat surfaces. The detailed role of the oxide support is then addressed with an emphasis on the genesis and structure of the MoS2 phase namely sulfidation rate, stacking, and orientation.

Increasing yield of nanocrystalline cellulose preparation process by a cellulase pretreatment

In this work the introduction of a cellulase treatment prior to NCC isolation was assessed. NCC was produced using sulfuric acid at two different concentrations (62 and 64% wt.). The effect of pore size for filtration step was also assessed. The smaller acid dose leaded to yields up to 65–70% and average size up to 160nm. It also produced crystals with reduced sulfur content (0.6–1%). Cellulase pretreatment influenced NCC characteristics, as it increased overall yield a 12%, increased average particle size around 35nm and reduced NCC sulfur content up to a 0.8%. We found that different conditions of enzymatic treatments led to quantitative differences on their effects on NCC. Acetate buffer used for enzymatic treatments was found to counteract effects of acid. The evidence presented in this work suggested that pretreating fibers with this cellulase represents a very interesting option to partially replace chemicals on NCC isolation.

Pervaporative desulfurization of gasoline – separation of thiophene/n-heptane mixture / Perwaporacyjne odsiarczanie benzyny – separacja mieszanin tiofen/n-heptan

Abstract This paper presents the recent advances in pervaporative reduction of sulfur content in gasoline. Methods of preliminary selection of membrane active layer material are presented. Interactions between gasoline components (typical hydrocarbon and sulfur species) and membranes are showed. Influence of pervaporation process parameters i.e. feed temperature, downstream pressure and feed flow rate on the separation efficiency is discussed. Investigations of the influence of sulfur concentration in fluid catalytic cracking (FCC) gasoline on membrane performance have been conducted. A series of PV tests was carried out to investigate the separation properties of the commercial composite membrane with an active layer made of poly(dimethylsiloxane) and to determine the efficiency of organic sulphur compound (thiophene) removal from model thiophene/n-heptane mixture depending on its concentration.

Assessment of cost as a function of abatement options in maritime emission control areas

This paper assesses cost as a function of abatement options in maritime emission control areas (ECA). The first regulation of air pollutions from ships which came into effect in the late 1990s was not strict and could easily be met. However the present requirement (2015) for reduction of Sulfur content for all vessels, in combination with the required reduction of nitrogen and carbon emissions for new-built vessels, is an economic and technical challenge for the shipping industry. Additional complexity is added by the fact that the strictest nitrogen regulations are applicable only for new-built vessels from 2016 onwards which shall enter US or Canadian waters. This study indicates that there is no single answer to what is the best abatement option, but rather that the best option will be a function of engine size, annual fuel consumption in the ECA and the foreseen future fuel prices. However a low oil price, favors the options with the lowest capex, i.e. Marine Gas Oil (MGO) or Light Fuel Oil (LFO), while a high oil price makes the solutions which requires higher capex (investments) more attractive.

Fatigue Cracking of a 3-MW Electric Motor Shaft

After approximately fifteen months of service, cracking was detected in the journal section of a 3-MW electric motor shaft used to drive a reciprocating gas compressor. A detailed failure analysis revealed sulfide inclusion and quench crack-initiated fatigue cracks. Two crack orientations were observed, axial and angular. The axial cracks are believed to be quench cracks which initiated along sulfide stringers; the angular cracks were found to be high-cycle fatigue cracks emanating from the axial cracks. Recommendations included the use of a reduced sulfur content shaft steel (0.010 wt.% max) and a pre-service non-destructive inspection to detect the presence of quench cracks or other surface imperfections.

Evolution of on-road vehicle exhaust emissions in Delhi

For a 40-year horizon (1990–2030), on-road vehicle exhaust emissions were evaluated, retrospectively and prospectively, for the largest urban agglomeration in India – the Greater Delhi region with a combined population of 22 million in 2011 (Delhi along with Ghaziabad, Noida, Greater Noida, Faridabad and Gurgaon). Emissions of particulate matter, sulfur dioxide, carbon monoxide and volatile organic compounds (VOCs) reached their peak during late 1990s through early 2000s after which they reduced significantly through year 2012. On the other hand, nitrogen oxides (NOx) and carbon dioxide show an increasing trend. The most reduction in emissions between 1998 and 2012 occurred as a result of implementation of four sets of vehicular emission standards, removal of lead, reduction of sulfur content, mandatory retirement of older commercial vehicles, and conversion of diesel and petrol run public transport vehicles to compressed natural gas. In addition, changes in the vehicular technology have also contributed to controlling emissions especially in case of auto-rickshaws and motorized two-wheelers, which changed from two-stroke to four-stroke. The rising trend of NOx along with the presence of VOCs indicates increasing tendency to form ground-level ozone and as a result, smog in the region. We predict that the current regime of vehicle technology, fuel standards, and high growth rate of private vehicles, is likely to nullify all the past emission reductions by the end of 2020s.

Fabrication of sulfur cathodes by wet-powder spraying and the understanding of degradation

In this work, wet powder spraying is presented as an alternative method for the fabrication of sulfur/carbon composite cathodes. The high dispersion and homogeneity of the cathode layer result in high capacity Li/S batteries. Additional use of LiNO3 as additive improved the discharge capacity to 800AhkgS−1, 400Ahkgcathode−1 (at 0.18C) and 410AhkgS−1, 205Ahkgcathode−1 (at 2C) after 50 cycles. The shuttle mechanism is reduced and a coulombic efficiency of around 100% is reached and maintained constant until 1000 cycles. To understand more the degradation mechanisms of the battery, Thermogravimetry combined with gas analysis (TG/MS) as well X-ray diffraction (operando and mappings) were applied. The formation of an amorphous phase during cycling that remains nearly stable in the later cycles is considered to be one of the main factors affecting capacity decay. Moreover, others processes are identified as contributors of battery degradation like PVDF decomposition, structural changes of carbon black, and reduction of sulfur content on the bulk of the electrode. These new insights on the degradation processes may contribute to the further understanding, selection of materials, and improvement of this battery.

PdCuAu ternary alloy membranes: Hydrogen permeation properties in the presence of H2S

PdCuAu ternary alloy membranes with different component compositions were synthesized by sequential electroless deposition of components onto porous stainless steel substrates. The ternary with the highest Au content, Pd69Cu14Au17, exhibited the highest hydrogen permeation flux, comparable to that of a Pd91Au9 membrane. Upon exposure to 100ppm H2S/H2 at 673 K for 24h, all PdCuAu membranes experienced flux reductions of ~55%, followed by recovery to ~80% of the initial hydrogen flux upon reintroduction of pure hydrogen at 400°C. Complete flux recovery after H2S exposure required hydrogen treatment at 500°C. X-ray diffraction (XRD) analysis of the H2S-exposed PdCuAu membranes revealed fcc alloy structure with no evidence of bulk sulfide formation. In agreement with the XRD results, sulfur was not detected in the bulk of H2S-exposed samples by energy dispersive spectroscopy (EDS). However, analysis of H2S-exposed PdCuAu alloys by X-ray photoelectron spectroscopy (XPS) depth profiling revealed low, but measureable, amounts of sulfur in the near-surface region, about 10nm in depth. The depth profiles of samples after hydrogen recovery treatment showed significantly reduced sulfur content. These results indicate that H2S exposure causes flux loss in PdCuAu alloys through a surface-poisoning mechanism, and that the surface sulfide can be removed—and flux recovered—by high temperature treatment in hydrogen.

Analysis of combustion, performance and emission characteristics of a diesel engine using low sulfur tire fuel

An alternative fuel for diesel engines was produced from waste vehicle tires by the method of pyrolysis. In order to reduce sulfur content of produced the liquid fuels, during the reaction Ca(OH)2 was used. Then, H2SO4 were used after the reaction and the sulfur content of the product was reduced by 83.75%. The properties of diesel fuel, low sulfur tire fuel and fuel mixtures of low sulfur tire fuel and diesel fuel were found. Then the prepared fuel blends and diesel fuel were tested in a diesel engine. Performance, combustion and emission parameters of the engine when using each fuel were obtained and comparisons were made with D2 fuel. Power, torque and mean effective pressure, mass fuel consumption, effective efficiency and bscf values presented. Results justify that the performance of the engine slightly lowers by using blends of LSTF. Cylinder pressure and heat release rate values of the test fuels usage were quite similar with those of D2. CO, HC, and smoke emissions were slightly higher while NOx emissions were lower for LSTF blends. All of these results indicate that desulfurized tire fuels with low percentages can be used as alternative fuel in diesel engine.