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Search Results: 1 - 10 of 4649 matches for " Mineral Coal = Sulfato "
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Arnaldo Sarti,Eugenio Foresti
Holos Environment , 2009,
Abstract: This paper presents and discusses the potential for use of pilot-scale anaerobic sequencing batch biofilm reactors (ASBBR) for the treatment of industrial wastewater containing high sulfate concentration. The pilot-scale ASBBR reactor (total volume=1.2 m3) containing biomass immobilized in inert support (mineral coal) was operated at sulfate loading rates varying from 0.15 to 1.90 kgSO4-2/cycle (cycle of 48h) corresponding to sulfate concentrations of 0.25 to 3.0 gSO4-2.L-1. Domestic sewage and ethanol were utilized as electron donors for sulfate reduction. The mean sulfate removal efficiencies remained in the range of 88 to 92% in the several sulfate concentrations obtained from 92 operational cycles. As post-treatment unit for the generated effluents by the sulfate reduction was used another reactor ASBBR in pilot-scale (total volume=385,0 L) with same inert support for biomass immobilization and different granulometry. The mean COD removal (mean influent=1450 mg.L-1) achieved 88% and total sulfide concentrations (H2S, HS , S2 ) remained in the range of 41 to 71 mg.L-1 during the 35 operational cycles of 48 h. The results demonstrated that the use of ASBBR reactors is an alternative potential for the sulfate removal and as post-treatment of generated effluent. = Este trabalho apresenta e discute o potencial de uso de reatores anaeróbios operados em bateladas seqüenciais com biomassa imobilizada (ASBBR), em escala piloto, no tratamento de água residuária industrial contendo elevadas concentra es de sulfato. No ASBBR, com volume total de 1,2 m3, preenchido com carv o mineral (meio suporte) foram aplicadas cargas de sulfato de 0,15 a 1,90 kg/ciclo com dura o de ciclo de 48 h, correspondendo, respectivamente, às concentra es de sulfato no afluente de 0,25 a 3,0 g.L-1. O esgoto sanitário e etanol foram usados como doadores de elétrons para a redu o do sulfato. As eficiências médias na redu o de sulfato ficaram entre 88 e 92% nos 92 ciclos operacionais. Como pós-tratamento dos efluentes gerados pela redu o de sulfato empregou-se outro reator ASBBR com volume total de 385,0 L e mesmo meio suporte para imobiliza o da biomassa, mas com diferente granulometria. A remo o média de DQO (valor médio afluente: 1450 mg.L-1) foi de 88%, enquanto as concentra es de sulfetos totais (H2S, HS , S2 ) mantiveram-se entre a faixa de 41 e 71 mg.L-1 nos 35 ciclos operacionais de 48h. Os resultados obtidos permitiram concluir que o uso de reatores ASBBR constitui-se em potencial alternativa tanto para a remo o de sulfatos, como no pós-tratamento dos efluentes gerados.
Steam Gasification of Different Brown Coals Catalysed by the Naturally Occurring Calcium Species  [PDF]
Peter N. Kuznetsov, Svetlana M. Kolesnikova, Ludmila I. Kuznetsova
International Journal of Clean Coal and Energy (IJCCE) , 2013, DOI: 10.4236/ijcce.2013.21001

The effects of the constituents of mineral matter in brown coals from different deposits of Kansk-Achinsk, Lenaand from Yallourn Basins on the structural parameters and steam gasification reactivities of respective coal chars at moderate temperature and at low and high pressure were studied in this paper. The data on how the preliminary decationization with diluted hydrochloric, acetic and sulphuric acids affect char gasification reactivities are presented. The importance of surface area and crystallinity of chars and the presence of naturally occurring metals on gasification reactivity is considered. Quantitative correlations between the calcium contents and the extents of gasification are revealed. The gasification results obtained in a flow reactor with steam stream and in an autoclave reactor at high pressure of gaseous products are compared. The catalytic effect of dispersed calcium oxide-carbonate particles produced from the naturally occurring calcium containing carboxylates was shown to be a key factor for char gasification reactivity, the effect in the flow reactor being much larger as compared to that in the autoclave reactor. This was mainly related to different forms of catalytically active calcium species and to the composition of the gaseous reaction mixture.

Dejan B Radi?,Marko O Obradovi?,Miroslav M STANOJEVI?,Aleksandar Jovovi?
Thermal Science , 2011, DOI: tsci1101267r
Abstract: Thermal power plants in the Republic of Serbia are making considerable efforts and even more considerable investments, not only to maintain electricity production at maximum design levels, but even to additionally increase the power output of existing generating units. Capacities of mills used in pulverized coal preparation are identified as one of the main constraints to achieving maximum mill plant capacity, while coal grindability is seen as one of the factors that directly affect capacities of the coal mills utilized in thermal power plants. The paper presents results of experimental investigation conducted for the purpose of determining Hardgrove grindability index of coal. The investigation was conducted in accordance with ISO 5074 and included analysis of approximately 70 coal samples taken from the open pit mine of Kolubara coal basin. Research results obtained indicate that coal rich in mineral matter and thus, of lower heating value is characterized by higher grindability index. Therefore, analyses presented in the paper suggest that characteristics of solid fuels analyzed in the research investigation conducted are such that the use coals less rich in mineral matter i. e. coals characterized by lower grindability index will cause coal mills to operate at reduced capacity. This fact should be taken into account when considering a potential for electricity production increase.
The Application of Microwave Energy in Mineral Processing – a Review
Michal Lovás,Ingrid Znamená?ková,Anton Zubrik,Milota Ková?ová
Acta Montanistica Slovaca , 2011,
Abstract: This paper presents a review of the application of microwave energy in the field of mineral processing at the Institute of Geotechnics,Slovak Academy of Sciences. The influence of microwave radiation of rocks on the failure disintegration of minerals and ores as well as,a modification of magnetic properties and thermal processing of rocks was studied. Moreover, the rate of microwave heating of minerals,effect of microwaves on coal desulphurisation and the extraction of diterpanes from coal were investigated.
Removal of mineral oil and wastewater pollutants using hard coal
Chemical Industry and Chemical Engineering Quarterly , 2009,
Abstract: This study investigates the use of hard coal as an adsorbent for removal of mineral oil from wastewater. In order to determine the efficiency of hard coal as an adsorbent of mineral oil, process parameters such as sorption capacity (in static and dynamic conditions), temperature, pH, contact time, flow rate, and chemical pretreatment were evaluated in a series of batch and continuous flow experiments. There were significant differences in the mineral oil removal for various pH values examined. The adsorption of mineral oil increased as pH values diverged from 7 (neutral). At lower temperatures, the adsorption was notably higher. The wastewater flow rate was adjusted to achieve optimal water purification. Equilibrium was reached after 10 h in static conditions. At that time, more than 99% of mineral oil had been removed. At the beginning of the filtering process, the adsorption rate increased rapidly, only to show a minor decrease afterwards. Equilibrium data were fitted to Freundlich models to determine the water-hard coal partitioning coefficient. Physical adsorption caused by properties of the compounds was the predominant mechanism in the removal process.
Characterization of Size and Density Separated Fractions of a Bituminous Coal as a Feedstock for Entrained Slagging Gasification  [PDF]
Nari Soundarrajan, Nandakumar Krishnamurthy, Sarma V. Pisupati
International Journal of Clean Coal and Energy (IJCCE) , 2013, DOI: 10.4236/ijcce.2013.24007
Abstract: Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced technologies that has potential to be used in a carbon constrained economy. However, gasification availability at several commercial demonstrations had run into problems associated with fouling of syngas coolers due to unpredictable flyash formation and unburnt carbon losses. Computer models of gasifiers are emerging as a powerful tool to predict gasifier performance and reliability, without expensive testing. Most computer models used to simulate gasifiers tend to model coal as a homogenous entity based on bulk properties. However, coal is a heterogeneous material and comminution during feedstock preparation produces particle classes with different physical and chemical properties. It is crucial to characterize the heterogeneity of the feedstocks used by entrained flow gasifiers. To this end, a low ash US bituminous coal that could be used as a gasifier feedstock was segregated into density and size fractions to represent the major mineral matter distributions in the coal. Float and sink method and sieving were employed to partition the ground coal. The organic and inorganic content of all density fractions was characterized for particle size distribution, heating value, ultimate analysis, proximate analysis, mineral matter composition, ash composition, and petrographic components, while size fractions were characterized for heating value, ash composition, ultimate and proximate analysis. The proximate, ultimate and high heating value analysis showed that variation in these values is limited across the range of size fractions, while the heterogeneity is significant over the range of density fractions. With respect to inorganics, the mineral matter in the heavy density fractions contribute significantly to the ash yield in the coal while contributing very little to its heating value. The ash yield across the size fractions exhibits a bimodal distribution. The heterogeneity is also significant with respect to the base-to-acid ratio across the size and density fractions. The results indicate that the variations in organic and inorganic content over a range of density and size classes are significant, even in the low ash, vitrinite rich coal sample characterized here. Incorporating this information appropriately into particle population models used in gasifier simulations will significantly enhance their accuracy of performance predictions.
Benefaction from Carbonation of Flue Gas CO2 as Coal Mining Filling  [PDF]
Y?ld?r?m ?. Tosun
Geomaterials (GM) , 2014, DOI: 10.4236/gm.2014.42007
Abstract: CO2 capturing, transport and sequestration by pressurized water dissolution and reacting by natural alkali lime and magnesia in coal fly ash or other sources become an industrial advantageous sequestration option resulting in green waste solutions or solid fines. Mg and Ca containing minerals are reacting with CO2 to form carbonates. Various types of fly ash materials may react with CO2 to form carbonate regarding ash composition and reaction parameters. Mineral sequestration of CO2 will also allow using the products in cement industry or as cement material in constructions with low cost. This paper discussed progress on coal mining filling by carbonation method using coal fly ash of Soma, Yatagan, Afsin Elbistan Power Stations. Other filler materials containing coal mine waste shale, fly ashes and foam concrete, and additives were searched for pretreatment methods to enhance cement reactivity; and in analyzing the structural changes to identify reaction paths and potential barriers.
Aplica o de enxofre em cobertura e qualidade fisiológica de sementes de feij o = Side dressing sulfur fertilization and physiological quality of bean seeds
M?nica Lúcia César,Nara Rosseti Fonseca,Mariana Zampar Toledo,Rogério Peres Soratto
Acta Scientiarum : Agronomy , 2008,
Abstract: A qualidade fisiológica das sementes pode ser afetada pelo estado nutricional das plantas, destacando-se, dentre os nutrientes, o fornecimento de enxofre, constituinte essencial dos aminoácidos. O trabalho objetivou avaliar os efeitos da aduba o sulfatada emcobertura sobre a qualidade fisiológica de sementes de feij o cv. Pérola. O delineamento experimental utilizado foi em blocos casualizados, com quatro repeti es. Os tratamentos foram constituídos por cinco doses de enxofre (0, 20, 40, 60 e 80 kg ha-1) em cobertura, na forma de sulfato de am nio, 22 dias após a emergência das plantulas. Avaliou-se a qualidade fisiológica das sementes logo após a colheita mediante testes de germina o e vigor. Aaplica o de enxofre, em cobertura, aumentou o vigor das sementes, avaliado pelo teste de envelhecimento acelerado; contudo, houve redu o do desenvolvimento inicial das plantulas com acréscimo da dose de S em cobertura até 50 a 60 kg ha-1. The physiological quality of seeds can be affected by the nutritional status of plants, with emphasis to sulfur supply, which is an essential component of amino acids. The research had as objective to evaluate the effects of side dressing sulfur fertilization on thephysiological quality of bean seeds, cv. Pérola. The experimental design was the completely randomized block, with four replications. The treatments consisted of five side dressing sulfur doses (0, 20, 40, 60, and 80 kg ha-1), in ammonium sulfate source, 22 days afterseedling emergence. The physiological quality of bean seeds was evaluated right after harvest, by tests of germination and vigor. Side dressing sulfur fertilization increased seed vigor, as evaluated by the accelerated aging test; however, there was a decrease in initial seedling development due to the increase in the S dose until 50 to 60 kg ha-1.
Inorganic Constituents in Coal
Ra?enovi? A.
Kemija u Industriji , 2006,
Abstract: Coal contains not only organic matter but also small amounts of inorganic constituents. More thanone hundred different minerals and virtually every element in the periodic table have been foundin coal. Commonly found group minerals in coal are: major (quartz, pyrite, clays and carbonates),minor, and trace minerals. Coal includes a lot of elements of low mass fraction of the orderof w=0.01 or 0.001 %. They are trace elements connected with organic matter or minerals comprisedin coal. The fractions of trace elements usually decrease when the rank of coal increases.Fractions of the inorganic elements are different, depending on the coal bed and basin. A varietyof analytical methods and techniques can be used to determine the mass fractions, mode ofoccurrence, and distribution of organic constituents in coal. There are many different instrumentalmethods for analysis of coal and coal products but atomic absorption spectroscopy – AAS is theone most commonly used. Fraction and mode of occurrence are one of the main factors that haveinfluence on transformation and separation of inorganic constituents during coal conversion.Coal, as an important world energy source and component for non-fuels usage, will be continuouslyand widely used in the future due to its relatively abundant reserves. However, there is aconflict between the requirements for increased use of coal on the one hand and less pollution onthe other. It’s known that the environmental impacts, due to either coal mining or coal usage, canbe: air, water and land pollution. Although, minor components, inorganic constituents can exert asignificant influence on the economic value, utilization, and environmental impact of the coal.
- , 2018,
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