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1
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Studies on the effect of coal particle size on biodepyritization of high sulfur coal in batch bioreactor

100%
Singh S., Srichandan H., Pathak A., Gahan C. S., Lee S., Kim D.-J., Kim B.-G.
Polish Journal of Chemical Technology
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2015
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vol. 17
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issue 1
97-102
EN
The moderate thermophilic mix culture bacteria were used to depyritize the Illinois coal of varying particle sizes (-100 μm, 100-200 μm, +200 μm). Mineral libration analysis showed the presence of pyrite along with other minerals in coal. Microbial depyritization of coal was carried out in stirred tank batch reactors in presence of an iron-free 9K medium. The results indicate that microbial depyritization of coal using moderate thermophiles is an efficient process. Moreover, particle size of coal is an important parameter which affects the efficiency of microbial depyritization process. At the end of the experiment, a maximum of 75% pyrite and 66% of pyritic sulphur were removed from the median particle size. The XRD analysis showed the absence of pyrite mineral in the treated coal sample. A good mass balance was also obtained with net loss of mass ranging from 5-9% showing the feasibility of the process for large scale applications.
2
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Changes in total active centres on particle surfaces during coal pyrolysis, gasification and combustion

100%
Gil S., Mocek P., Bialik W.
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EN
In the paper, on the basis of our studies and the available literature data, a model of changes in the number of active centers corresponding to the structure of the reactive coal particle has been developed. A new distribution function that links the specific surface area of a particle with its porosity and reaction degree has been proposed. An equation for estimation of changes in this parameter during the reaction, on the basis of the initial value, has been presented. In the range of our data and the analysis of the literature data, the model, with satisfactory accuracy, describes internal structural changes of coal and coal char particles. The present results may constitute a basis for complex modelling of coal conversion processes.Based on the results it was found that the total active centres are related to the internal surface area and porosity of the particle. For a specific coal type, this value depends on the porosity, true density and size of the particle. Changes in total active centres, when these structural properties during thermal conversion of coal are considered, are described in equations.
3
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Microwave saturation of EPR spectra of oxidised coal

100%
Pilawa B., Więckowski A., Pietrzak R., Wachowska H.
Open Chemistry
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2007
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vol. 5
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issue 1
330-340
EN
Microwave saturation of multi-component EPR spectra of oxidized lignite Mequinenza (Spain) with a carbon content of 65.1 wt % and with a high sulphur content of 10.3 wt % was studied. The coal was oxidized with nitric acid (NHO3), peroxyacetic acid (PAA), and in O2/Na2CO3 system. Three different groups of paramagnetic centres exist in the coal samples analyzed. The EPR spectrum of the demineralised coal was a superposition of broad Gauss (ΔB pp = 0.75 mT), broad Lorentz 1 (ΔB pp = 0.42 mT) and narrow Lorentz 3 lines (ΔB pp = 0.08 mT). The three EPR components with linewidths: 0.58–0.77 mT (Gauss line), 0.30–0.39 mT (Lorentz 1 line) and 0.05–0.06 mT (Lorentz 3 line) were recorded for the oxidized coal. The g-values were obtained for the samples studied in the ranges 2.0043–2.0046 (Gauss lines), 2.0035–2.0038 (Lorentz 1 lines) and 2.0032–2.0034 (Lorentz 3 lines). The broad Gauss and Lorentz 1 lines saturate at low microwave powers. The narrow Lorentz 3 lines of demineralised coal were not saturated at microwave power from the range considered. After the coal oxidation with HNO3, PAA and in O2/Na2CO3 system, the microwave saturation of the narrow Lorentz 3 lines was also observed, which indicated a degradation of the multi-ring aromatic structures upon oxidation. [...]
4
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Changes in total active centres on particle surfaces during coal pyrolysis, gasification and combustion

100%
Gil S., Mocek P., Bialik W.
Chemical and Process Engineering
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2011
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issue 2
5
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Sequential leaching analysis to investigate the sintering process of coal, cereal pellets and wood pellets Ash

88%
Szydełko A., Nowak-Woźny D., Urbanek B., González Valdés L., Rybak W., Szydełko A., Nowak-Woźny D., Urbanek B., González Valdés L., Rybak W.
Chemical and Process Engineering
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2019
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vol. 40
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issue 2
6
Content available remote

Composition of extraction products from alkylated high-sulphur coals

88%
Kozłowski M., Wachowska H., Yperman J.
Open Chemistry
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2003
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vol. 1
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issue 4
366-386
EN
Products of reductive and non-reductive methylation of two high-sulphur coals (Mequinenza and Illinois No. 6) have been extracted by dichloromethane. It has been established that the efficiency of the transformation of coal to the products soluble in CH2Cl2 is higher for coals subjected to non-reductive methylation by the Liotta method than for those after reduction in the potassium/liquid ammonia system. The extracts and the extraction residues were subjected to elemental analysis, IR spectroscopy, and AP-TPR (Atmospheric Pressure-Temperature Programmed Reduction) measurements. It has been shown that the main species undergoing extraction by CH2Cl2 are aliphatic compounds or aromatic structures of low degree of condensation. The effect of the extraction on the sulphur groups in coal has been discussed.
7
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Simulation of circulating fluidized bed gasification for characteristic study of pakistani coal

88%
Ramzan N., Athar M., Begum S., Ahmad S. W., Naveed S.
Polish Journal of Chemical Technology
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2015
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vol. 17
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issue 1
66-78
EN
A process model for turbulent pressurized circulating fluidized-bed coal gasifier is created using ASPEN PLUS software. Both hydrodynamic and reaction kinetics parameter are taken into account, whose expressions for fluidized bed are adopted from the literature. Various reactor models available in ASPEN PLUS with calculator as External Block are nested to solve hydrodynamics and kinetics. Multiple operational parameters for a pilot-plant circulating fluidized-bed coal gasifier are used to demonstrate the effects on coal gasification characteristics. This paper presents detailed information regarding the simulation model, including robust analysis of the effect of stoichiometric ratio, steam to coal ratio, gasification temperature and gasification agent temperature. It is observed that, with the increase in the flow rate of air, the components hydrogen, carbon monoxide, carbon dioxide and methane reduce, which causes the Lower Heating Value (LHV) of synthesis gas (Syn. Gas) to decrease by about 29.3%, while increment in the steam flow rate shows a minute increase in heating value of only 0.8%. Stoichiometric ratio has a direct relationship to carbon conversion efficiency and carbon dioxide production. Increasing the steam to coal ratio boosts the production of hydrogen and carbon monoxide, and causes a drop in both carbon dioxide concentration and the conversion efficiency of carbon. High gasifying agent temperature is desired because of high concentration of CO and H2, increasing carbon conversion and LHV. A high gasifying agent temperature is the major factor that affects the coal gasification to enhance H2 and CO production rapidly along with other gasification characteristics.
8
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Chronostratigraphic and Depth Variability of Porosity and Strength of Hard Coals in the Upper Silesian Basin

88%
Bukowska M., Sanetra U., Wadas M., Bukowska M., Sanetra U., Wadas M.
Gospodarka Surowcami Mineralnymi
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2012
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vol. 28
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issue 4
9
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The Influence Of Calcite On The Ash Flow Temperature For Semi-Anthracite Coal From Donbas District

88%
Čarnogurská M., Příhoda M., Pyszko R., Širillová Ľ., Palkóci J.
Chemical and Process Engineering
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2014
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vol. 35
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issue 4
515-525
EN
This paper presents the results of research focused on the lowering of ash flow temperature at semianthracite coal from Donbas district by means of additive (calcite) dosing. Ash fusion temperatures were set for two coal samples (A, B) and for five various states (samples of ash without any additives, with 1%, with 3%, with 5% and with 7% of the additive) in total. The macroscopicphotographic method was used for identifying all specific temperatures. Obtained outputs prove that A type coal has a lower value of sphere temperature than B type coal in the whole scope of percentage representation of the additive. The flow temperature dropped in total from 1489 °C to 1280 °C, i.e. by 14% during the test of coal of type A with 7% of the additive; while it was near 10% for coal of type B (from 1450 °C to 1308 °C). Numerical simulations of the process showed that it is not effective to add an additive with a grain size lower than 280 μm by means of wastevapour burners.
10
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The forms of occurrence and chemical composition of sulfides in the LW Bogdanka bituminous coal deposits of the Lublin Coal Basin

88%
Bielowicz B., Misiak J.
Gospodarka Surowcami Mineralnymi
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2018
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vol. 34
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issue 3
11
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Influence of the geology of coal deposits on their extraction and urbanistic development: a case study of Petřvald (Czech part of the Upper Silesian Basin)

75%
Sivek M., Jirásek J., Sivek M., Jirásek J.
Gospodarka Surowcami Mineralnymi
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2020
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vol. 36
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issue 2
12
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Changes in the spontaneous combustion tendency of humic coals according to their petrographic composition and physico-chemical properties

75%
Bielowicz B., Bielowicz B.
Gospodarka Surowcami Mineralnymi
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2020
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vol. 36
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issue 2
13
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Content available

The Influence Of Calcite On The Ash Flow Temperature For Semi-Anthracite Coal From Donbas District

75%
Čarnogurská M., Příhoda M., Pyszko R., Širillová Ľ., Palkóci J.
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issue 4
14
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The Impact of the Degree of Coalification on the Sorption Capacity of Coals from the Zofiówka Monocline

75%
Godyń K., Dutka B.
Archives of Mining Sciences
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2018
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vol. 63
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issue 3
15
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Lab-Scale Investigations During Combustion of Agricultural Residues and Selected Polish Coals

75%
Kordylewski W. K., Mościcki K. J., Witkowski K. J.
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issue 2
16
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Lab-Scale Investigations During Combustion of Agricultural Residues and Selected Polish Coals

75%
Kordylewski W. K., Mościcki K. J., Witkowski K. J.
Chemical and Process Engineering
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2014
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vol. 35
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issue 2
249-262
EN
Preliminary lab-scale investigations were conducted on slagging abatement in biomass-firing by fuel mixing. Three agriculture biomass fuels and olive cake were used in the experiments. Polish lignites and bituminous coals were examined as anti-sintering additives. The effects of chlorine release, potassium retention and ash sintering were examined by heating samples of biomass fuels and additives in the muffle oven and, next, firing them in the laboratory down-fired furnace at the temperature in the range of 800-1150ºC. The obtained slag samples were analysed on: chlorine and potassium content, sintering tendency and crystalline components. Among the examined coals lignite from Turów mine and bituminous coal from Bolesław Śmiały mine appeared to be the most effective in potassium retention in aluminosilicate and chlorine release from slag. Possibly the major factor of these coals which reduced ash sintering was relatively high content of kaolinite
17
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Microlithotype profile of the coal seam no. 116/2 (Libiąż Beds) with facial interpretation - ZG 'Janina' (USCB)

63%
Misiak J., Misiak J.
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issue 2
18
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THE INFLUENCE OF FEEDSTOCK TYPE AND OPERATING PARAMETERS ON TAR FORMATION IN THE PROCESS OF GASIFICATION AND CO-GASIFICATION

51%
Kamińska-Pietrzak N., Howaniec N., Smoliński A.
Ecological Chemistry and Engineering S
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2013
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vol. 20
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issue 4
747-761
EN
Increasing energy demand, limited resources of fossil fuels and environmental aspects are the main rationales of the research efforts aiming at wider utilization of renewable resources and waste in energy generation systems. Gasification technologies are based on thermochemical processing of solid, liquid and gaseous fuels to gas of the composition dependent on kind of gasification agent and operating parameters used. The range of applications of the product gas includes basically chemical and petrochemical industries. Its utilization in power generation systems is also of industrial interest since the environmental impact of gasification technologies is lower and the process efficiency is higher than of coal-fired power plants and it enables to utilize wide range of fuels, including fossil fuels, biomass, industrial waste and various fuel blends. One of the most important operational issues related with thermochemical processing of biomass and waste is the formation of tars, which reduces the energy efficiency of the process and causes technical problems in a system operation. The amount and quality of tars depends on the chemical composition of a fuel, a gasification agent used and its ratio to fuel flow, process temperature and pressure as well as the construction of a gasifier. In the paper review of the research on the influence of operating parameters and kind of feedstock on tar formation and composition in the process of gasification and co-gasification is presented.
PL
Rosnące zapotrzebowanie na energię, ograniczone zasoby surowców energetycznych oraz aspekty środowiskowe stanowią główną przyczynę prac badawczych, których celem jest szersze użytkowanie odnawialnych źródeł energii oraz odpadów do celów energetycznych. Technologie zgazowania oparte są na procesie termochemicznej przeróbki paliw stałych, płynnych i gazowych do gazu o składzie zależnym od zastosowanego czynnika zgazowującego i wartości parametrów eksploatacyjnych. Zakres zastosowania produktu gazowego z procesu zgazowania obejmuje głównie przemysł chemiczny i petrochemiczny. Jego zastosowanie w produkcji energii elektrycznej również jest interesujące z uwagi na mniejszy negatywny wpływ technologii zgazowania na środowisko i większą sprawność procesu w porównaniu z systemami kotłów węglowych. Technologie zgazowania umożliwiają również użytkowanie różnych surowców energetycznych, począwszy od paliw kopalnych poprzez biomasę, odpady przemysłowe i różne mieszanki wsadowe. Jednym z najbardziej istotnych aspektów eksploatacyjnych związanych z przetwarzaniem termochemicznym biomasy i odpadów jest tworzenie się substancji smolistych, co obniża sprawność energetyczną procesu i powoduje problemy techniczne w eksploatacji instalacji. Charakterystyka ilościowa i jakościowa substancji smolistych uwarunkowana jest składem chemicznym paliwa, rodzajem czynnika zgazowującego i wartością stosunku natężenia przepływu tego czynnika do nadawy paliwa, temperaturą oraz ciśnieniem procesu, a także rodzajem zastosowanej konstrukcji reaktora. W pracy przedstawiono przegląd badań w zakresie wpływu parametrów eksploatacyjnych oraz rodzaju paliwa na ilość i skład substancji smolistych w procesie zgazowania i współzgazowania.
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