Combustion Of Sulfur Research Articles

A new approach for the prediction of combustible sulphur in coal in terms of coal washability data and calorific value

In this study, determination of petrographical properties and washability characterisation for Uzulmez District (Zonguldak coal basin) coals were realised. In the context of this study, it was proposed that each coal seam has its own function for total sulphur content and calorific value. The reason behind calorific value steep decrease from float fraction to sink fraction and corresponding total sulphur amount increase from sink fraction to float fraction was discussed. The discussion furtherly resulted in understanding of combustible and non-combustible distribution of sulphur and a new method of determining this proportion was proposed. The overall evaluation showed that the combustible sulphur percentages analysed (both in coal and ash) and predicted has correlation coefficients (R2) of 0.90 for PIC, 0.78 for PIRIC, 0.79 for NASIFOGLU and 0.85 for SULU coal seams, respectively. Corresponding correlation coefficients were regarded as significant since they are in a same manner with respect to washability tendencies. [Received: March 15, 2019; Accepted: August 7, 2020]

Comparison of SCIPUFF predictions to SO2 measurements from instruments on the MetOp-A, MetOp-B, Aura and Suomi satellites from the 2016 fire at Al-Mishraq

On October 20th, 2016, Daesh (Islamic State) set fire to the sulfur production and storage site at Al-Mishraq, Iraq. The fire burned continuously for seven days resulting in the release of a buoyant dynamic sulfur dioxide (SO2) toxic plume extending geographically for over 300 km. This Al-Mishraq event provides an opportunity for scientists to address probabilistic atmospheric transport and dispersion (PATD) hazard model performance across multiple downwind scales over a large area. In using any PATD model, a fair evaluation of the model depends on the quality of the source term – especially for a very dynamic source term such as a burning sulfur stockpile. An innovative approach to derive such a source for Al-Mishraq was explored by the Swedish Defence Research Agency (in Swedish Totalförsvarets forskningsinstitut, or FOI). The experts from FOI characterized the SO2 source term based on satellite observations, which reflect vertically-integrated concentrations and are expressed in Dobson units (DU). The work throughout this paper is a novel approach and leverages the FOI analysis to evaluate a PATD, the Second Order Closure Integrated Puff (SCIPUFF) transport and dispersion code as adapted within the Hazard Prediction and Assessment Capability (HPAC). SCIPUFF predictions are compared to the satellite-based vertically-integrated SO2 measurements from the Moderate Resolution Imaging Spectro-radiometer (MODIS) instruments. Satellite measurements were available at 07Z and 11Z daily from 21 to 26 Oct 2016. A 1-DU background was assumed. SCIPUFF over predicts (factor of 2) column density (DU) peaks in the near field (40, 80, and 120 km) and under predicts in the far field (200, 280 and 320 km); best agreement is at the 160 km arc. Plume direction errors of 25–80° are found when comparing the azimuths of peak observed and predicted column densities. Performance metrics traditionally used for model evaluation included fractional bias (FB), normalized mean-square error (NMSE), and figure of merit in space (FMS). The FB at 07Z was −0.2 to +0.09 across the eight arcs, 40–320 km downwind. Upon analyses, SCIPUFF showed approximate equal over and under prediction for the 07Z; and the FB at 11Z under predicted seven of eight arcs, with values that ranged from −0.07 to +0.36. The NMSE was 3.11–5.06 with no identifiable trends on arc distance. The FMS, averaged over each arc, by day, was between 0.31 and 0.56. Higher values were found in the early and later stages of the fire 21–22 and 25–26 October. Lower averaged FMS values were calculated for 23–24 October which corresponds to a period where the fire burned hotter and SO2 mass was injected to higher altitudes of 1–4 km.

Five Supplementary Therapies for COVID-19

The COVID-19 is characteristic of both damage of the respiratory system and the immune system or both similarities of SARS and AIDS. These features decide difficulty of specific treatment. The worldwide transmission and higher fatality rate call for new skills for prevention and treatment. Here, we recommend five supplementary therapies for COVID-19. (1) Discharging viruses from lungs by exhaling, coughing and suction are firstly emphasized. (2) Semireclining posture instead of lying supine for lightening hyperemia and edema of inflammation and dyspnea. (3) Non-steroidal anti-inflammatory coldrex, such as tylenol and paracetamol, can be safely used for controlling inflammation. (4) Vitamin B2 must be used for repairing of mucous membrane of the respiratory tract and as antioxidants. (5) It is most emphasized that sulfur dioxide (SO2) produced from burning sulfur and explosion of firecrackers has a potent antimicrobial effect for air disinfectant and killing viruses in the lungs. In addition to the general therapies, all these methods or therapies can be simply and effectively supplied to patients for discharging viruses, inhibiting viruses and killing viruses, and for recovery from damages.

Numerical evaluation of a novel double-concentric swirl burner for sulfur combustion

A burner system for the efficient and clean combustion of sulfur is introduced, which serves as a key component in a novel solar power cycle using sulfur as chemical storage medium of solar energy. In order to validate the proposed design concept, highly-resolved numerical simulations have been performed. The current setup is operated with a thermal load of 20 kW or power density of 5 MW/m3. Two nozzle configurations with different swirl intensities (SI) of the airflow are studied. A large inner recirculation zone is observed for the nozzle with a high SI (HSI), which leads to a strong radial dispersion of the sulfur spray and a broad, short flame in the combustion chamber; although this HSI design is beneficial from the viewpoint of flame stabilization, it causes a large number of sulfur droplets hitting the chamber wall. In contrast, the nozzle design with a low SI (LSI) yields a narrow spray and a long jet flame, with much less droplets hitting the wall. The HSI nozzle shows an overall higher flame temperature compared with the LSI nozzle, which is confirmed to be caused by burning at a higher local fuel equivalence ratio. This is attributed to the strong inner recirculation flow generated by the high swirl intensity, which results in an enhanced evaporation and mixing of sulfur droplets with air. In terms of operability and NOx emission, the LSI burner is preferred due to less sulfur droplets hitting the chamber wall and the lower flame temperature.

Study of the distribution of rubber particles in ground tire rubber/polypropylene blends

Goal number 12 of the UN 2030 Agenda for Sustainable Development is sustainable consumption and productions. Recycling has a central role in assuring to meet the target in 2030. Only in EU, the annual total waste of spent tire is 3.7 million tons [1]; it is impelling to find a sustainable way to recycle this material. This article investigates the feasibility of the use of ground tire rubber (GTR) as feedstock for injection molding by blending it with polypropylene (PP). Nine different blends were created by changing the content between rubber and polypropylene and by using three different rubber powders. A particular attention has been paid on the study of the distribution of the rubber particles in the blends. The investigation showed an uneven dispersion between GTR and PP, leading to different surface finishing and mechanical property. From the sulfur combustion analysis it was possible to observe higher content of sulfur, and thus of GTR, in the position of the sample far from the injection gate. Local concentration of rubber powder caused an increase in the surface roughness and a decrease in the hardness of the material.

Research of combustion of flickering pyrotechnical products

The process of combustion of flickering pyrotechnic products containing metallic and non-metallic fuel was investigated. A research method based on the comparison of experimental and calculated data is proposed, which allows the creation of flickering pyrotechnic products with a given duration of the interval between flashes.Flickering pyrotechnic products, the burning of which is accompanied by a series of bright flashes, are used in the technique of fireworks to create original light paintings.According to the known works, the range of characteristics of such products is quite wide. In particular, the duration of the interval between flashes may range from hundredths of a second to several seconds. However, in literature there are no details of the reasons pulsating nature of combustion and quantitative characteristics of the processes that occur at the same time. Due to the lack of a theoretical base, pyrotechnic product developers have to go empirically, relying only on experimental experience. An unresolved scientific problem is the lack of a theoretical approach to the development of flickering pyrotechnic articles with a given duration of the interval between flashes.The purpose of the article is to obtain data on the quantitative characteristics of the processes occurring during the burning of flickering pyrotechnic articles, and to develop a methodology that will allow to create products whose combustion parameters - primarily the duration of the interval between flashes - would be predictable in advance.The pulsating character of the combustion is a consequence of the parallel course of processes having different time scales. There are at least two types of such processes: fast exothermic combustion reactions and slow heat loss to the environment. The speed of the latter, among other things, depends on the size of the heat transfer surface, which is determined by the diameter of the product, if it has the shape of a body of rotation. By varying the diameter obviously can affect the rate of heat transfer, and with it the nature of combustion. From this assumption follows the task of this study - to investigate the burning of flickering products of cylindrical shape, which differ only in diameter.The results were obtained by comparing experimental data on the duration of the interval between flashes with the data obtained in the calculated way.The temporal characteristics of the combustion of the samples were determined using a storage oscilloscope, to which a photocell was connected. The interval between flashes was determined by the screen scale as the distance between the peaks of the waveform.According to our observations, the following occurs in the process of sample burning. During ignition, non-metallic fuel - sulfur, is first lit. It lights up easily but burns slowly, warming the composition of the site to the ignition temperature of the metal fuel. The latter lights up harder but burns quickly with a flash.The sharp flash of metallic fuel is accompanied by spreading hot combustion products, because they are unable to ignite the next batch of metal. However, the sulfur continues to burn, so the cycle repeats. The duration of the interval between flashes is determined by the heating time of the sample portion of the burning sulfur to the ignition temperature of the metallic fuel.The study confirmed the assumption that to change the duration of the interval between flashes of flashing pyrotechnic products within certain limits, it is enough to change their diameter.

Safety and environmental reasons for the use of Ni-, Co-, Cu-, Mn- and Fe-based oxygen carriers in CLC/CLOU applications: An overview

Chemical looping combustion (CLC) is presently considered as a cutting-edge combustion technology that enables capturing CO2 without major energy penalty for its separation. The technology involves the use of solid metal oxides, so-called oxygen carriers (OCs), which are alternately subjected to the redox reactions. In the last years, most investigations on the CLC process have been focused on the development of synthetic oxygen carriers, which are much more efficient and have greater resistance compared to natural materials. Synthetic OCs can be based on Ni-, Co-, Cu-, Mn- and Fe- oxides, the use of which however may cause various kinds of threats. The paper provides an overview of Ni, Co, Cu, Mn, and Fe-based OCs taking into account safety operation of CLC reactors as well as health and environmental issues. Therefore, the purpose of this work is to study the impact of different solid oxygen carriers on human beings, animals and natural environment. It has been revealed among others that OCs based on Ni- and Co- oxides may cause various environmental and health problems, while Cu- oxide might be hazardous especially for aquatic wildlife. Moreover, it was shown that Ni-based OCs have tendency to create Ni-S compounds, such as Ni3S2 or NiSO4, in reactions with combustible sulphur contained in the fuel. Toxicity investigations prove, for instance, that rats exposed to 15 mg/6 h/day of NiSO4 die in 10 days after the test. Otherwise, Mn- and Fe- oxides are generally safe in use.

A perspective on fossil fuel based flue gas emission reduction technologies

AbstractThe aim of this paper is to specify the role of coal‐fired power plants (CFPPs) in the formation of global emissions/harmful pollutants and to discuss the benefits of current and future technologies to minimize environmental damage. In this regard, pollutant/emission reduction technologies from CFPPs are discussed in detail by considering the environmental and global warming aspects. Pollutant gases from CFPPs around the globe have always been the most important source of environmental concern in societies. In particular, due to the burning of the coal without taking the necessary precautions, the nitrogen in the coal and combustion air and the combustible sulfur components in the coal content are oxidized and released to the atmosphere as nitrogen oxides (NOx) and sulfur oxides (SOx). Another pollutant from power plants is carbon monoxide (CO). CO is a colorless, odorless, poisonous gas that can remain in the atmosphere for a long time. In addition, significant amounts of carbon dioxide (CO2) occur by virtue of the combustion of coal. CO2 emission is in the class of greenhouse gases causing global warming. As a result of this study, the factors causing the formation of harmful pollutants in CFPPs are determined and present and potential suggestions are provided for the environmental sustainability of such facilities. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

Kto może zostać potępiony? Lektura kontekstualna Ap 21,8

Autor artykułu dokonuje analizy kontekstualnej Ap 21,8. Tekst ten mówi o karze wiecznej, używając metafory jeziora ognia i siarki. Analiza tego obrazu w kontekście Apokalipsy św. Jana, całej Biblii, jak i literatury pozabiblijnej, prowadzi do wniosku, że jest to miejsce czy stan wiecznego potępienia, pozbawione nadziei, bez żadnej możliwości odmiany losu tych, którzy tam się znajdą. Jest ostatecznym pozbawieniem się możliwości wspólnoty z Bogiem. Ap 21,8 wymienia również listę potencjalnie zagrożonych wiecznym potępieniem. Analizowana w świetle pozostałych list z Apokalipsy św. Jana (9,20-21; 21,27; 22,15) pokazuje, że nie jest ona kompletna, a raczej rodzaj portretu lub modelu kogoś, kto może zostać potępiony. Wszystkie wymienione w tym tekście wady czy grzechy – w większym lub mniejszym stopniu – odnoszą się do idolatrii albo są jej konsekwencją. Stają się w ten sposób obrazem świata pogańskiego, w którym żyją chrześcijanie i który może zagrażać im od wewnątrz. W takim kontekście Ap 21,8 jest rodzajem przestrogi dla chrześcijan powołanych do wspólnoty zbawionych. Celem ich życia jest udział w Mieście Świętym (doskonałej wspólnocie z Bogiem i Barankiem), a nie w „jeziorze ognia i siarki”. Chrześcijanie mają żyć jak zbawieni, a nie jak ludzie tego świata, świata pogańskiego zanurzonego w idolatrii. Perykopa Ap 21,8-9 odczytana w kontekście całej księgi wskazuje na wszystkie szanse i możliwości, jakie otrzymują chrześcijanie, aby mieć udział w nieograniczonym życiu wiecznym.

Distillery waste management in line with the concept of circular economy

The paper presents physico-chemical characteristic of distillery residue and ashes after its calcination at 650 and 850°C, that may become a potential energy source due to a relatively high heat of combustion and low content of sulphur and moisture. The chemical composition of the obtained ash as well as fresh distillery residue determines its further use for fertilising purposes. Adducing the legislative regulations none of the analysed key heavy metal exceeds norms allowable in the regulation referring to organic and organo-mineral fertilisers. Proposed solution can be considered as waste minimization technology with energy recovery by rational recycling of nutrients. Such an application will exert an additional positive influence on the circular economy potential.

Respirable Mercury Particulates and Other Chemical Constituents in Festival Aerosols in Delhi

The display of fireworks emits a large amount of gaseous and particulate pollutants which accumulate in the atmosphere for a short period and have adverse effects on human health, and climate. Significant accumulation takes place due to episodic emissions of fireworks during special events such as New Year, Cricket match and Deepawali festivals etc. This study reports PM10 loads and chemical compounds during episodic emission of Deepawali by collecting aerosols samples during Pre-Deepawali period (Pre), on the day of Deepawali (D), and Post-Deepawali period (Post), in order to assess the change in chemical composition of air due to fireworks. PM10 aerosol samples were collected by using Respirable Dust Sampler (RDS) at JNU in South Delhi. The samples were analyzed for chemical constituents such as Particulate Mercury (HgP) by using Differential Pulse Anodic Stripping Voltammetry (DPASV) technique, Elemental Carbon (EC) and Organic Carbon (OC) by using a thermal/optical analyzer and metal oxides by using Energy Dispersive X-Ray (EDX). For the morphological characterization of particles Scanning Electron Microscope (SEM) was used. The results showed that particulate mercury (HgP) and PM10 loadings were relatively higher in the samples collected on Deepawali day as compared to Pre- Deepawali and Post-Deepawali samples. The order of metal oxides was recorded as K>Al>S>Cl>Ca>Fe and Ba, Mg and Ti were present only on the day of Deepawali, indicating its contribution from fireworks. OC and EC showed a strong correlation with PM10 concentrations. A strong linkage of K with Al (r=0.92) and S (r=0.83), as well as of Fe with Ca (r=0.94) was observed during Deepawali festival week. Also, S showed its association with PM10 concentration suggesting its emission from combustion of sulphur containing raw material of fireworks. The study suggests that the firework emissions significantly affect air quality, increasing the possibility of respiratory illness.

A thermochemical study on the primary oxidation of sulfur

ABSTRACTSeveral chemical reactions related to the oxidation and combustion of sulfur are investigated using a number of computational chemistry methods with the objective of determining appropriate methods for use in developing an elementary reaction mechanism for oxidation of sulfur. Calculations are focused on thermochemical properties and reaction energetics for reactive species and transition state structures for reactions in the oxidation/combustion of sulfur. Reactions involving several intermediates resulting from the reactions of S2 with oxygen were investigated with the density functional theory B3LYP (with several basis sets) and BB1K/GTLarge. The composite ab-initio methods G2, G3, G3MP2, G3B3, G3MP2B3 and CBS-QB3 were also used. Enthalpies of a series of sulfur compounds and transition state structures are calculated using the ab-initio and DFT calculations. The calculations were combined with isodesmic reaction analysis, whenever possible, in order to cancel error and improve the accuracy of the calculations. Results show that all B3LYP DFT calculations including the 6–311++G(3df,2p) basis set show poor outcome in estimating the enthalpy of reactions involving S2. The six composite methods have all shown consistency with each other and their calculated reaction energies/bond energies are in good agreement with the available literature. Kinetic parameters for calculation of the kinetic parameters on SO3 dissociation to SO2 and O using the canonical transition state theory are reported.

Technical Study of the Performance of Liquid Sulfur Combustion in the Process of Sulfuric Acid Production

The production process of sulfuric acid is carried out in stages from combustion of liquid sulfur to SO$_2$, then to SO$_3$ and dissolving SO$_3$ in aqueous sulfuric acid solution to concentrated sulfuric acid (high concentration). The success of the production process is very dependent on the initial combustion process into SO$_2$, physical parameters on the liquid sulfur characteristics and the nozzle geometry. The process of burning liquid sulfur depends on the pattern of atomization in the geometry of the nozzle and its fluid characteristics. Liquid sulfur is included in non-newtonian fluids, so the atomization process requires an understanding of its characteristics. The atomization mechanism at the nozzle depends on 3 parameters including viscosity, surface tension and density. In non- Newtonian fluid 3 parameters are sensitive to changes in pressure and temperature. In terms of the geometry of the tip nozzle diameter, smaller diameter, the atomization process is better, but a decrease in temperature will cause clogging. Individual installation of temperature and pressure sensors for each nozzle is chosen so that the atomization of each nozzle can be controlled.

The development of a novel process for the production of calcium sulfoaluminate

Abstract In an industrial climate where the reduction of carbon emissions is paramount to meeting industry standards for a sustainable future, the cement industry is looking for alternative and creative solutions to reducing its carbon footprint and energy consumption. The title review develops a novel process for the production of calcium sulfoaluminate (CSA) cement, a material produced in the Chinese construction industry for use as a rapid hardening binder for 5 decades; but now undergoing rapid change. The novelty of the proposed process lies partly in its source of sulfur. Typically provided by gypsum in conventional raw feeds, the novel process instead sequesters sulfur into the cement solids through the combustion of elemental sulfur. This combustion event, in turn, contributes towards the calorific value required to heat and maintain kiln temperatures by burning fossil fuel, e.g. natural gas. The combustion of sulfur also provides various added benefits. The resultant sulfur-containing atmosphere in the reaction system provides a protective environment which represses S volatilisation at the operating temperatures used for CSA production, ca 1200–1300 °C. The novel process was developed with the intention for eventual commercial production in Doha, Qatar. The combustion of sulfur would be additionally beneficial due to the nation’s production of vast quantities of natural gas; elemental sulfur is a by-product of the Claus process, used for the desulfurisation of natural gas or sour crude. The proposed novel process would thereby utilise a waste product, i.e. sulfur, for the production of a low carbon cement product.

Evolution of Stored-Product Entomology: Protecting the World Food Supply

Traditional methods of stored-product pest control were initially passed from generation to generation. Ancient literature and archaeology reveal hermetic sealing, burning sulfur, desiccant dusts, and toxic botanicals as early control methods. Whereas traditional nonchemical methods were subsequently replaced by synthetic chemicals, other traditional methods were improved and integrated with key modern pesticides. Modern stored-product integrated pest management (IPM) makes decisions using knowledge of population dynamics and threshold insect densities. IPM programs are now being fine-tuned to meet regulatory and market standards. Better sampling methods and insights from life histories and ecological studies have been used to optimize the timing of pest management. Over the past 100 years, research on stored-product insects has shifted from being largely concentrated within 10 countries to being distributed across 65 countries. Although the components of IPM programs have been well researched, more research is needed on how these components can be combined to improve effectiveness and assure the security of postharvest food as the human population increases.

Determination of Total Sulfur, Sulfate, Sulfite, Thiosulfate, and Sulfolipids in Plants.

In response to oxidative stress the biosynthesis of the ROS scavenger, glutathione is induced. This requires the induction of the sulfate reduction pathway for an adequate supply of cysteine, the precursor for glutathione. Cysteine also acts as the sulfur donor for the sulfuration of the molybdenum cofactor, crucial for the last step of ABA biosynthesis. Sulfate and sulfite are, respectively, the precursor and intermediate for cysteine biosynthesis and there is evidence for stress-induced sulfate uptake and further downstream, enhanced sulfite generation by 5'-phosphosulfate (APS) reductase (APR, EC 1.8.99.2) activity. Sulfite reductase (SiR, E.C.1.8.7.1) protects the chloroplast against toxic levels of sulfite by reducing it to sulfide. In case of sulfite accumulation as a result of air pollution or stress-induced premature senescence, such as in extended darkness, sulfite can be oxidized to sulfate by sulfite oxidase. Additionally sulfite can be catalyzed to thiosulfate by sulfurtransferases or to UDP-sulfoquinovose by SQD1, being the first step toward sulfolipid biosynthesis.Determination of total sulfur in plants can be accomplished using many techniques such as ICP-AES, high-frequency induction furnace, high performance ion chromatography, sulfur combustion analysis, and colorimetric titration. Here we describe a total sulfur detection method in plants by elemental analyzer (EA). The used EA method is simple, sensitive, and accurate, and can be applied for the determination of total S content in plants.Sulfate anions in the soil are the main source of sulfur, required for normal growth and development, of plants. Plants take up sulfate ions from the soil, which are then reduced and incorporated into organic matter. Plant sulfate content can be determined by ion chromatography with carbonate eluents.Sulfite is an intermediate in the reductive assimilation of sulfate to the essential amino acids cysteine and methionine, and is cytotoxic above a certain threshold if not rapidly metabolized and can wreak havoc at the cellular and whole plant levels. Plant sulfite content affects carbon and nitrogen homeostasis Therefore, methods capable of determining sulfite levels in plants are of major importance. Here we present two robust laboratory protocols which can be used for sulfite detection in plants.Thiosulfate is an essential sulfur intermediate less toxic than sulfite which is accumulating in plants in response to sulfite accumulation. The complexity of thiosulfate detection is linked to its chemical properties. Here we present a rapid, sensitive, and accurate colorimetric method based on the enzymatic conversion of thiosulfate to thiocyanate.The plant sulfolipid sulfoquinovosyldiacylglycerol (SQDG) accounts for a large fraction of organic sulfur in the biosphere. Aside from sulfur amino acids, SQDG represents a considerable sink for sulfate in plants and is the only sulfur-containing anionic glycerolipid that is found in the photosynthetic membranes of plastids. We present the separation of sulfolipids from other fatty acids in two simple ways: by one- and two-dimensional thin-layer chromatography.

Computational model of large-capacity molten sulphur combustion spray efficacy and process efficiency

Computational model of large-capacity molten sulphur combustion spray efficacy and process efficiency

Sulphuric acid production via Chemical Looping Combustion of elemental sulphur

A relevant objective of the sulphuric acid (H2SO4) production industry today is to obtain sulphur dioxide (SO2) gas streams with the highest possible SO2 concentration after the elemental sulphur combustion stage in order to reduce both capital and operating costs. A new technology, Chemical Looping Combustion (CLC), is able to generate gaseous streams that are highly concentrated in combustion products by means of oxygen transfer from air to the fuel using a solid oxygen carrier. This work proposes a new process for H2SO4 production via CLC and using elemental sulphur as fuel. An oxygen carrier with high sulphur resistance should be used for this purpose. The analysis of this process has brought promising results, such as the easy integration of the CLC system into the entire H2SO4 production plant and the confirmation that this is a process in which the energy potential of sulphur is exploited to a very high degree. Furthermore, the proof of concept was carried out by burning elemental sulphur in a 500Wth CLC unit with a high sulphur-resistant oxygen carrier based on iron oxide, Fe20γAl. This work presents the first ever results of elemental sulphur combustion by an oxygen carrier. Complete combustion of sulphur to SO2 was achieved, and no deactivation of the oxygen carrier was observed. Considering all the results obtained in this work, it can be concluded that the production of H2SO4 via CLC is a feasible technology which can provide a series of relevant techno-economic benefits in comparison with current industrial production process.

Modeling and optimization of fine coal beneficiation by hydrocyclone and multi-gravity separation to produce fine lignite clean coal

ABSTRACTWe evaluated the suitability, contribution to the national economy, and environmental impact of hydrocyclone and Multi-Gravity Separation (MGS) processes using fine-sized coal taken from the Soma coal sludge pond. The lignite coal tailings were treated by a two-stage concentration scheme for the recovery of fine clean coal. Pre-enrichment experiment parameters were determined by the Taguchi experimental design method, and the results were interpreted by the Statistical Packages for the Social Sciences (SPSS) 15.0 program to evaluate the optimum parameter values. The tailings initially contained 54.82% ash and had a LCV of 2,279 kcal/kg; after hydrocyclone pre-enrichment, the concentrate was 42.60% ash and had a calorific value of 2,573 kcal/kg (55.75% coal yield). After the final enrichment process, the ash of the pre-concentrated coal was decreased to 24.21% and left a clean coal with a base calorific value of 3,226 kcal/kg (36.16% coal yield). The total sulfur of the obtained clean coal was 0.52% and the combustible sulfur rate was 0.10%. To reduce the ash content of the obtained clean coal, a decantation process was performed that decreased the ash content to 21.84% and the base calorific value was increased to 4,109 kcal/kg.

Two-Step Synthesis of Tungsten and Molybdenum Disulfides

Efficient two-step technique of tungsten and molybdenum disulfides obtaining from metal nanopowders produced by EEW and elementary sulphur is described. Tungsten and molybdenum nanopowders surface area dependence on wire length is studied. Features of metal and sulphur combustion process are discussed. It is determined sulphur excess in reagents 15 wt.% results in mono-phase metal disulfide formation with small free sulphur concentration in reaction products.