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Search Results: 1 - 10 of 294 matches for " pyritic sulphur "
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High Pressure Oxydesulphurisation of Coal—A Parametric Study
Moinuddin Ghauri,Abrar Inayat,Muhammad Tariq Bashir,Salmiaton B. Ali,Keith R. Cliffe
Energies , 2013, DOI: 10.3390/en6041930
Abstract: The current study is focused on controlling sulphur emissions by pre-treating coal to remove sulphur prior to combustion using the oxydesulphurisation technique. Three British coals were chosen for the study. Working with these coals gave a better insight to the oxydesulphurisation reactions for pyritic and organic sulphur. Effect of air and oxygen pressure in a fixed time interval on sulphur removal was studied by series of experimental runs at various temperatures. Heating value recoveries were significant. Increase in oxygen content is reported as a measure of carbon loss. The coal samples were analyzed according to British standard methods. Experimental results demonstrate that the sulphur removal was enhanced with the increase in air pressure, particularly up to 100 bars, with only a small decrease in calorific value at a particular temperature. Increasing temperature was witnessed to be more important in sulphur removal than increasing pressure.
Model for sulfide weathering in pyritic wastestone
Dai Zhaohu,Wang Zhihai
环境科学学报(英文版) , 1992,
Abstract: The model for sulfide weathering in pyritic wastestone was studied based on the sulfide weathering rate in pyritic wastestone as well as relationship between the accumulating amount of sulfide weathered during pyritic wastestone weathering and some factors affecting weathering.The relationship is mainly based on the results of simulating experiment of pyritic wastestone weathering and analysis of field samples of the acid water. The model may be practical to predict the rate of sulfide weathering in pyritic wastestone of Dexing Copper M ine and the quality of the acid mine drainage generated by the wastestone weathering.
Sumpor u ugljenu (Sulphur in Coal)
Ra?enovi?, A.
Kemija u Industriji , 2004,
Abstract: The presence of sulphur in coal possesses important environmetal problems in its usage. The sulphur dioxide (S02) emissions produced during coal combustion account for a significant proportion of the total global output of anthropogenic SO2. The extent of sulphur separation depends on several variables such as the form of sulphur in coal, intimacy of contact between minerals and the products of devolatilization. The total sulphur in coal varies in the range of 0.2 - 11 wt %, although in most cases it is beetwen 1 and 3 wt %. Sulphur occurs in a variety of both inorganic and organic forms. Inorganic sulphur is found mainly as iron pyrite, marcasite, pyrrhotite, sphalerite, galena, chalcopirite and as sulphates (rarely exceeds w = 0,1 %). Organic sulphur is found in aromatic rings and aliphatic functionalities usually as mercaptans, aliphatic and aryl sulfides, disulfides and thiophenes. Organic and pyritic sulphur quantities depend on coal rank. Higher rank coals tend to have a high proportion of labile sulphur. All the organic sulphur is bivalent and it is spread throughout the organic coal matrix. Sulphur occurs in all the macerals and most minerals. Vitrinite contains the major part of organic sulphur and metals. Elemental sulphur is produced during coal weathering. The depolymerization methods as pyrolysis and hydrogenation are very drastic methods wich change the structure of the coal and the sulphur groups. In the case of pyrolysis, high levels of desulphurization, in chars and additional production of liquid hydrocarbon can be achieved. Thiophenes and sulphides were the major sulphur components of tars from coal pyrolysis. Hyrdogen sulphide and the lower mercaptans and sulphides were found in the volatile matters. Hydrogen sulphide and thiophenes are practically the only sulphur products of coal hydrogenation. H2S is produced in char hydrodesulphurization. A number of options are available for reducing sulphur emissions including the utilisation of coals with low sulphur concentrations (typically < 1 wt %), the removal of cleaning prior to utilisation. The methods for the removal of sulphur from coal can be divided into: physical, chemical and microbiological. The mineral sulphur components can be removed or reduced by commercial methods of coal washing, flotation and agglomeration. A number of chemical desulphurization for the removal of, both, pyritic and organic sulphur have been advocated. The chemical desulphurization methods however, have two major drawbacks. Namely, they are often expensive and they destroy the caking properties of coal. Ce
Sulphur in Poland
Bli??an Peter,Kondela Julián,Seman Peter
Acta Montanistica Slovaca , 2001,
Abstract: Poland belongs to one of the last countries with native sulphur mining. Its history begun in 15th century. Deposit area of Tarnobrzeg re-presents 80% of all known sulphur reserves in this country. All of explored deposits in this area were created by metasomatic alteration of sulphur bearing limestones with sulphur mineralised liquids, which arised from melt gypsum. The average content is 25 - 30% of sulphur in Tarnobrzeg area. Considerable parts of deposits are created by calcite and native sulphur. Gypstone, baryte and stroncianite have only minera-logic occurencies. The extensive native sulphur deposits account for 88% of the country′s sulphur production. There were five sulphur mines in operation: Jeziórko, Grêbów, Machów I, Machów II and Basznia, but operations in Basznia were ended in 1992 and Machów and Machów II were liquidated. The sixth mine Osiek is currently producing. Only the Machów I mine operated an open-pit extraction and refining process, the other four mines producing sulphur using a modified Frasch method that gives elemental sulphur of up to 99,9% purity. Sulphur is an important export commodity with foreign sales totalling around 1.5 - 2.5 Mt/y. Modern benefication methods, which allowing to achieve sulphur from hydrocarbons, are causing decrease of native sulphur prices in the world and bringing about reduction of mining activities for this raw material in Poland.
THE PALEOENVIRONMENTAL SIGNIFICANCE OF PYRITIC NODULES FROM LOKPANTA OIL SHALE INTERVAL IN THE PETROLEUM SYSTEM OF LOWER BENUE TROUGH, NIGERIA
O.A. Ehinola,Qin Shengfei,A.A. Onibonoje
Petroleum and Coal , 2010,
Abstract: Petrographic, Scan Electron Microscopy (SEM), X-Ray Diffraction (XRD), rare earth element (REE) and sulphur isotope (d34S) studies were carried out on the pyritic nodules collected from the Lokpanta oil shale interval of the Lower Benue Trough, Nigeria. This is to ascertain the origin of the nodules and their implications in the hydrocarbon generation and accumulation in the region. The mineralogical composition (from SEM and XRD) of the nodules indicates calcite, pyrite, barite and anhydrite as common minerals. The petrographic studies show that the pyrite is subhedral to euhedral in texture. Barite and anhydrites occur as pores, veins and cavity fillings and together with pyrite constituted the only sulphate minerals. Calcite is the only carbonate mineral and occurred as the matrix. The sulphur d34S values range from +0.9 to +1.6‰ with an average of +1.6‰ which correspond to authigenic pyrite. The REEs result show high enrichment of LREEs relative to HREEs suggesting seawater source while the positive europium (>1) anomaly values indicate anoxic event, and reducing diagenetic conditions in a significantly high temperature. Although, the Lokpanta oil shale interval is deposited under an Oceanic Anoxic Event (OAE) and is capable of generating hydrocarbon in the study area, the authigenic nature and euhedral texture of the pyrite grains suggest metamorphic or thermal alteration for the formation of the nodules. Moreover, the volcanic intrusions and hydrothermal activities within the study area could also enhance the formation of the pyritic nodules. The generation and accumulation of hydrocarbon in the Lower Benue Trough could further be investigated using heat flow model.
Experimental and Parameterization Method for Evaluation of Dry Deposition of S Compounds to Natural Surfaces  [PDF]
Ranjit Kumar, K. Maharaj Kumari
Atmospheric and Climate Sciences (ACS) , 2012, DOI: 10.4236/acs.2012.24043
Abstract: This paper deals with parameterization method based on meteorological parameters for calculation of dry deposition of S compounds on natural surface (leaf of Cassia siamea) and direct measurement method. A scheme based on meteorological parameters has been evolved to calculate the dry deposition theoretically and a computer program has been developed. Experimentally dry deposition flux of S on leaf of Cassia siamea was measured by exposing the leaf surfaces on non-dewy, non-foggy and non rainy days and washing the leaf surfaces with deionised water and samples were analyzed by Dionex Dx-500 Ion Chromatograph. Atmospheric concentration of SO2 was 3.54±1.41 μg m-3 and particulate SO42- was 2.72±1.15 μg m-3. Theoretically obtained dry deposition velocity of SO2 and SO42- are 0.32 cm s-1 and 0.75cm s-1, respectively. The calculated deposition of S as total sulphate (gaseous SO2 and particulate SO42-) to Cassia leaf was 2.05±0.78mg m-2 d-1 and experimentally obtained dry deposition of S as sulphate was 1.07±1.35 mg m-2 d-1. The experimentally and theoretically obtained mean values for S as SO42- are comparable.
Characterization of Particulate Matter from Power Plant Stack Emissions in Southern Zimbabwe  [PDF]
V. P. Dudu, L. Mapfaire, B. Masamha, A. Kanda, S. Nemadire
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.33033
Abstract:

The study investigated the effects of four major particulate matter (PM) components namely sulphur, pulsar ash, carbon residue and ammonium components on the physical damage of sugarcane. A cyclone ambient kit tetra detector was used to quantify the components of the particulate matter at 2, 4, 6 and 8 km both in the windward and leeward sides of the power plant. This was done during the oncrop and offcrop season over a period of sixteen weeks. Eight sampling points were selected in an area of 2500 m2. Plant leaves were visually assessed for physical damage and the percentage of damage was noted. The results of the study were analyzed using SPSS version 16 and General Linear model-multivariate analysis to determine variation between the different means of components. Results showed that all PM components were only detected in the leeward side throughout the oncrop season and in the first two weeks of the offcrop. Ash and carbon deposition decreased with increasing distance. Ammonium components and sulphur were deposited only at 6 and 8 km. The percentage damage of the sugar cane was observed in the leeward side during the oncrop season. The physical damage caused by carbon and ash was observed in the 2 and 4 km distances whereas that caused by ammonium components and sulphur was observed in the 6 and 8 km distances.

SULPHUR DEFICIENCY IN DAIRY CALVES REARED ON PASTURE OF Brachiaria decumbens
Ortolani, Enrico Lippi;
Ciência Rural , 2001, DOI: 10.1590/S0103-84782001000200011
Abstract: the clinical picture of sulphur (s) deficiency is described by the first time in brazilian dairy calves. twelve crossbred six-month-old weaned dairy calves, reared on pasture of s-deficient brachiaria decumbens, were used. the calves were randomly assigned in two groups of six calves each to verify the influence of s supplementation on some clinical and serum biochemical variables. all animals were fed a basal-supplement mix containing macro and microlements, urea and ground corn grain added (41gs/kg) or not of s (elemental s; 1g s/kg), for six months. at the end of the experiment, the s-supplemented calves had higher mean body weight (p < 0.01), body condition score (p < 0.016), serum inorganic sulphate concentration (p < 0.001) and serum albumin concentration (p < 0.01) than the s-deficient calves. the unsupplemented dairy calves exhibited loss of body condition, retarded growth, weight loss and slight apathy.
EFFECT OF SOLE AND ASSOCIATIVE ACTIONS OF ELEMENTAL SULFUR AND INOCULATION SULFUR OXIDIZING BACTERIA ON GROWTH AND NUTRIENTS CONTENTS OF PEPPER PLANTS AND THE USED SOILS
S. A. Ibrahim,M. H. El-Halfawi,Hala Kandil
Soil Forming Factors and Processes from the Temperate Zone , 2011,
Abstract: A pot experiment was conducted to study the effect of elemental sulfur (E.S) rate (2.5 g/kg soil) and sulfur oxidizing bacteria on pepper plant and some chemical properties of two representative soil samples varying in their texture and CaCO3 content. Pepper was grown in Shobrakheet clay loam and Nobaria sandy loam soils for 50 days. Each soil was treated with elemental sulfur (2.5 g kg-1 soil) and inoculated with two sulfur oxidizing bacteria (S.O.B. No.8 and S.O.B. ATCC 8158). Elemental sulfur with or without sulfur oxidizing bacteria increased shoot dry weights of pepper plants as compared with control. The highest effect was observed with E.S + ATCC 8158 treatment which resulted in increasing the pepper shoot dry weights from 1.36 to 2.08 g pot-1 with the clay loam soil and from 0.77 to 1.37 g pot-1 with the sandy loam soil. The same treatment resulted in the highest plant content of S, N, P, K and micronutrients.
INFLUENCE OF ELEMENTAL SULFUR AND/OR INOCULATION WITH SULFUR OXIDIZING BACTERIA ON GROWTH, AND NUTRIENT CONTENT OF SORGHUM PLANTS GROWN ON DIFFERENT SOILS
Hala Kandil,M. H. El-Halfawi,S.A. Ibrahim
Soil Forming Factors and Processes from the Temperate Zone , 2011,
Abstract: A pot experiment was conducted to study the effect of elemental sulfur(E.S) rates (300 and 600 ppm) and/or sulfur oxidizing bacteria (S.O.B. ATCC 8158) on growth and nutrients content of sorghum plants grown on different soils (sandy soils(I & II) and clay loam soil).The obtained results could be summarized in the followings:Sorghum plants:Significant increases over the control were observed in fresh and dry weights of sorghum plant as well as its content of SO4=, N, P, K, Fe, Mn, Zn and Cu by using all the sulfur and/or the oxidizing bacteria treatments. Addition of E.S (300 & 600 ppm) in combination with S.O.B. ATCC 8158 significantly increased both fresh and dry weights as well as SO4=, N, P, K, Fe, Mn, Zn and Cu contents of sorghum plants grown on the used soils as compared with either of them alone.E.S rates (300 & 600 ppm) significantly increased the fresh and dry weights as well as all the studied nutrients content (SO4=, N, P, K, Fe, Mn, Zn and Cu) of sorghum plants grown on the different soils as compared with S.O.B. ATCC 8158 treatment alone. The highest rate of E.S (600 ppm) significantly increased all the previous parameters under study as compared with the lower rate (300 ppm). The highest values of fresh and dry weights as well as nutrients content (SO4=, N, P, K, Fe, Mn, Zn and Cu) of sorghum plants grown on the used soils were obtained by 600 ppm E.S + S.O.B. ATCC 8158 treatment followed by 600 ppm E.S; 300 ppm E.S + S.O.B. ATCC 8158; 300 ppm E.S; S.O.B. ATCC 8158 and control treatments in decreasing order.The used soils:E.S rates (300 & 600 ppm) and/or S.O.B. ATCC 8158 decreased pH values of the used soils after 3, 6 and 9 weeks from sowing as compared with their corresponding control treatments. The values of pH of sand soil (I) and clay loam soil slightly decreased by time i.e they decreased from 3 weeks to 9 weeks from plantation. E.S rates (300 & 600 ppm) with or without inoculation the used soils with S.O.B. ATCC 8158 significantly increased SO4=, N, P, K, Fe, Mn, Zn and Cu content of all the used soils as compared with the control and sole S.O.B. ATCC 8158 treatments each alone. The highest values of SO4=, N, P, K, Fe, Mn, Zn and Cu contents of sandy soils (I & II) and clay loam soil took the same trend of these nutrient in sorghum plants. The highest rate of E.S (600 ppm) significantly increased SO4=, N, P, K, Fe, Mn, Zn and Cu contents in all the used soils as compared with the lower rates (300 ppm). All the values of fresh and dry weights as well as all the determined elements in sorghum plants and the used soils were higher wh
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