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    Tytuł:
    Determination of the lower calorific and ash values of the lignite coal by using artificial neural networks and multiple regression analysis
    Autorzy:
    Gulec, Mahmut
    Gulbandilar, Eyyup
    Powiązania:
    https://bibliotekanauki.pl/articles/109973.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    lignite chemical analyses
    artificial neural networks
    Seyitomer lignite
    Tuncbilek lignite
    Opis:
    The calorific value of coal varies depending on type of coal and foreign matter content. The calorific value of coal from pits is determined by analyzing moisture, volatile matter, ash and sulfur content in laboratories. This analysis process imposes a burden on businesses both in terms of time and cost. However, calorific value, in particular, can be determined through simpler methods by using ash and moisture values. The aim of this study was to develop a model that reduces the time and labor costs of coal companies by determining the calorific value and ash content of coal with the back-propagation algorithm of artificial neural networks (ANN). The model design was developed based on the data that was obtained from the laboratory analyses of raw coals from the pits of Tuncbilek and Seyitomer mining areas in Turkey. The values of moisture, volatile matter, original ash and sulfur were determined as input variables, and the lower calorific values and ash content were selected as output variables. The lower calorific values (LCV) and Ash estimated by the developed model were compared with the LCV obtained in the laboratory tests and the results showed a correlation. In addition, two different ANN models and multiple regression analysis (MRA) were developed to obtain the single output of the LCV and ash parameters with similar features. As a result, the ANN model and MRA equation models proposed in this study was shown to successfully estimate the LCV and ash content of coals without performing laboratory analyses.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 2; 400-406
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Parameters and methods for evaluation of lignite processing method into biogas
    Autorzy:
    Szubert, Agnieszka
    Kapusta, Piotr
    Matyasik, Irena
    Powiązania:
    https://bibliotekanauki.pl/articles/109812.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    lignite
    biogasification parameters
    coals biodegradation
    Opis:
    In the article parameters of lignite organic matter conversion into biogas are collated and verified in terms of the process evaluation and control. Possibilities and limitations of usage of the parameters for this type of the process are also indicated. The following parameters were selected: a gas amount and its quality, isotope analysis of the gas produced, measurement of dissolved organic carbon (DOC) in biomass-free liquid media, presence of the VFA (volatile fatty acids) and other possible intermediates of the process in liquid medium, pH, as well as (not discussed in this article) microbiological analyses. On the basis of experiments of Polish lignite biogasification, examples of application of these parameters in laboratory scale for identification of the biodegradation lignite reactions occurrence are presented and discussed. We found that apart from analyses of the biogas produced, the following parameters are also possible to be implemented: DOC, specific surface area of solids measured before and after the process, and the parameters that are normally used for evaluation of rocks’ maturity and origin, i.e. S1, S2 and HI determined from Rock-Eval analysis, as well as GC-MS analysis of EOM (Extractable Organic Matter) separated from lignite. For the analyses of the EOM’s, relatively high amount of solid is required for measurements, limiting its implementation for continuous operations in practice. It was indicated that measurement of elementary coals’ composition, total organic carbon (TOC) in solids or of pH of the liquid are not applicable parameters for verification of the progress of the lignite biogasification process.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2020, 56, 2; 396-405
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flotation of lignite pretreated by sorbitan monooleate
    Autorzy:
    Zhang, W.
    Tang, X.
    Powiązania:
    https://bibliotekanauki.pl/articles/109467.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    sorbitan monooleate
    flotation
    lignite
    FTIR
    XPS
    SEM
    Opis:
    In this study, sorbitan monooleate was used to pretreat lignite prior to flotation tests. First, the lignite sample and water were mixed with 0%, 0.5%, 1%, 1.5% and 2% (on the basis of the weight of the coal) of sorbitan monooleate to produce five types of flotation slurries. FTIR, XPS and SEM were used to analyze the surface properties of the lignite sample. The flotation tests were used to indicate the improvements in flotation of lignite after the sorbitan monooleate pre-treatment. FTIR and XPS results showed that there are many oxygenated functional groups in lignite such as carboxyl group and hydroxyl groups. Furthermore, SEM results showed that there are many holes on the lignite surface. These holes will be filled with water in the flotation pulp. The flotation results indicated that sorbitan monooleate can improve the lignite flotation at low concentrations of sorbitan monooleate. However, the flotation behavior of lignite deteriorated at higher concentrations of sorbitan monooleate.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2014, 50, 2; 759-766
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improved flotation of heat treated lignite with saline solutions containing mono and multivalent ions
    Autorzy:
    Ozdemir, O.
    Ersoy, O. F.
    Guven, O.
    Turgut, H.
    Cinar, M.
    Çelik, M. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/109640.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    flotation
    heat treatment
    lignite
    DLVO
    Saline Solutions
    Opis:
    Flotation of lignites is inherently difficult. However, pre-heat treatment of coal is also known to make coal surfaces more hydrophobic possibly through removal of water entrapped in the structure of coal. In this context, the objective of this study was, therefore, to determine changes in the hydrophobicity of some lignites under moderately controlled heat treatment and correlate the flotation response of lignites in different salt solutions of NaCl, KCl, CaCl2, and MgCl2 without using any reagent. The results of flotation tests suggested that under the present test conditions, it was possible to float thermally pre-treated lignite samples of partially hydrophobic character in salt solutions in the absence of collector and frother. In addition, the effect of heat treatment on hydrophobicity, and in turn flotation was explained by a theoretical model based on extended DLVO interactions to quantify the effects of both heat treatment and salt concentration on bubble-particle interactions. The results of theoretical modeling suggested that the removal of hydrogen containing groups from coal surfaces significantly contribute to the electrical double layer and hydrophobic forces that govern the magnitude of energetic barrier and also the extent of bubble-particle attachment.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1070-1082
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lignite cleaning in NaCl solutions by the reverse flotation technique
    Autorzy:
    Zhang, H.
    Liu, Q.
    Powiązania:
    https://bibliotekanauki.pl/articles/110516.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    lignite
    reverse flotation
    NaCl
    kinetics
    coal preparation
    Opis:
    A cleaning possibility of low (BD) and high ash content (IM) lignites in NaCl solutions using a reverse flotation technique was studied. Preliminary test results indicated that BD lignite cannot be cleaned effectively in the traditional manner because gangue was floated first rather than a combustible material. Further studies indicated that the lignite cleaning in NaCl solutions using the reverse flotation technique is possible. However, a large quantity of dodecyl amine hydrochloride (DAH) was required. A lower ash content in a concentrate can be obtained by addition of NaCl. A concentrate yield can be im-proved by addition of starch. Under the test conditions, for BD lignite with the ash content in the feed 15.19%, the ash content in the concentrate 11.44% and the concentrate yield 67.38% were obtained. Similarly, for IM lignite with the ash content in the feed 57.40%, the ash content in the concentrate 32.90% and the concentrate yield 25.08% were obtained. The flotation rate constant k and maximum ash recovery ε∞ significantly increased with the NaCl concentration.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2015, 51, 2; 695-706
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Peat and lignite leaching process with tetralin in autoclave to produce oil
    Autorzy:
    Depci, T.
    Karta, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/110838.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    leaching
    Adiyaman peat
    Elbistan lignite
    paraffinic-low waxy oil
    Opis:
    Instead of directly burning a lignite having low calorific value and peat, the Elbistan lignite (L) and the Adiyaman peat (P) were mixed and leached in an autoclave to obtain an oil to not only provide the demand for energy but also protect the environment. The effects of the peat ratio in the mixture on the properties of co-liquefaction products (oil, char, asphaltene, and preasphaltene) and oil yield were investigated in details. The products were characterized by XRD, FTIR, and elemental analysis. In addition, the composition of the oil was identified by GC/MS, showing that the peat ratio did not affect the chemical composition of the oil due to the high lignin content and the nearly same elemental compositions. On the other hand, the oil yield for a co-liquefaction process was found as 34.3% to be higher than the average value of oil yields obtained from the individual feeds (24.3% for lignite and 28% for peat), showing the synergistic effects between the lignite and peat. The obtained oil was paraffinic-low waxy oil with 5138.62 kcal/kg of calorific value and 0.94 g/cm3 density. Finally, it was suggested that the production of a more valuable product using the peat and the lignite having low calorific value will not only contribute more to the country's economy in future but also be better for the environment, instead of directly burning them.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 2; 334-342
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Adsorption behavior of surfactants on lignite particles with different densities in aqueous medium
    Autorzy:
    Wang, J.
    He, Y.
    Wen, B.
    Ling, X.
    Xie, W.
    Wang, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/110538.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    interfacial surface free energy
    adsorption
    lignite
    surfactant
    Washburn equation
    Opis:
    Lignite is well known for its strong hydrophilicity and hard-to-float properties. However, the surface free energy of the solid is made up of two components, that is the Lifshitz-van der Waals and acid-base interaction energy. Differences in these two components between the low ash (lower density) and high ash fraction (higher density) provide a benefit for improving the separation efficiency through introducing surfactants in flotation. In this paper, thermodynamic characterization of three density lignite fractions was measured by a Washburn dynamic method. Combining the Washburn equation and Van Oss-Chaudhury-Good theory, the surface free energy components of three samples were calculated according to the wetting process by n-hexane, diiodomethane, deionized water and ethylene glycol. The Lifshitz-van der Waals part of surface free energy reduced with the coal density increase, especially between fractions of -1.45 g/cm3 and 1.45-1.80 g/cm3, while the Lewis base part increased slightly. The interfacial interaction free energies between the surfactant and lignite in aqueous medium indicated that the low hydrophilic index benefited for the stronger adsorption intensity. Increase of the surfactant Lifshitz-van der Waals component increases the adsorptive intensity on lower density lignite and the repulsive intensity on higher density lignite, which is beneficial for separation.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 2; 996-1008
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Use of natural soda ash production process waste for SO2 removal
    Autorzy:
    Tunali, Y. I.
    Ertunç, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/207588.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    removal SO2
    desulfurization fule gas
    lignite
    Chem Cad 60
    usuwanie SO2
    odsiarczanie spalin
    węgiel brunatny
    Opis:
    Results of ChemCad©6.0 simulation have been presented on usability of natural soda ash production process waste in order to remove SO2 from flue gas. Properties and concentrations of the solutions used in this study belong to the waste stream of Eti Soda Inc., and the flue gas compositions were acquired from an existing thermal power plant. SO2 and H2O feed rates and flue gas entrance temperature to the absorption tower were optimized through the response surface methodology (RSM) in order to attain highest SO2 removal yields. It has been found that SO2 removal remained at 33.83% when the waste composition was lower than 2 wt. % while 100% SO2 removal was reached as the waste composition was increased to 8 wt. %. This result clearly demonstrates that treatment of natural soda ash production process waste can be done safely and economically while serving as an SO2 removal agent at the same time.
    Źródło:
    Environment Protection Engineering; 2017, 43, 2; 69-80
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of fertilization with sewage sludge and sewage sludge-based mixtures of heavy metals mobility
    Autorzy:
    Ociepa, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/207987.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    sewage sludge
    cadmium
    coal ash
    fertilizers
    lead
    lignite
    potassium
    soil pollution
    zinc
    bioavailable metals
    plant biomass
    osady ściekowe
    kadm
    popiół węglowy
    nawozy
    ołów
    węgiel brunatny
    potas
    zanieczyszczenie gleby
    cynk
    metale biodostępne
    biomasa roślin
    Opis:
    The presented work aimed at evaluating a fertilizing mixture of sewage sludge, brown coal and brown coal ash enriched with potassium mineral fertilizer on mobility of heavy metals. The effects of fertilization were compared with the effects obtained from fertilization with: sewage sludge, mixture of sewage sludge and mineral fertilizer, mixture of brown coal and mineral fertilizers and mineral fertilizers. Soil was slightly contaminated with zinc and cadmium (II°) and showed elevated concentration of lead (I°). The uptake of heavy metals by plants depended on the concentration of bioavailable metal forms determined with 0.01 M CaCl2 and 1 M HC1. Fertilization with the mixture of sewage sludge, brown coal, brown coal ash enriched with potassium mineral fertilizer resulted in the reduction in the concentrations of zinc by 30-38%, cadmium by 28-34% and lead by 11-50% in plant biomass compared to soil with no fertilization.
    Źródło:
    Environment Protection Engineering; 2013, 39, 2; 55-66
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Removal of Cr(III) ions from water and wastewater by sorption onto peats and clays occurring in an overburden of lignite beds in central Poland
    Autorzy:
    Kyzioł-Komosińska, J.
    Rosik-Dulewska, Cz.
    Dzieniszewska, A.
    Pająk, M.
    Krzyżewska, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/208228.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    chromium compounds
    chlorine compounds
    hydrogen bonds
    iron compounds
    isotherms
    lignite
    peat
    sorption
    metal-organic complexes
    water
    wastewater
    związki chromu
    związki chloru
    wiązania wodorowe
    związki żelaza
    izotermy
    węgiel brunatny
    torf
    sorpcja
    kompleksy metaloorganiczne
    woda
    ścieki
    Opis:
    Sorption capacities of low-moor peats and Neogene clays from the overburden of lignite beds in Central Poland for Cr(III) ions as chloride and metalorganic complex ions have been investigated. The binding mechanisms and sorption parameters were determined based on the Freundlich and Langmuir nonlinear sorption isotherms. The sorption capacities of studied materials for Cr(III) ions depended on their properties (porosity, average pore diameters, specific surface area and content of Fe hydroxyoxides) as well as charge of Cr(III) ions, functional groups and their diagonal lengths. Cr(III) ions from chlorides were bound onto sorbents via Coulomb attraction and by Fe hydroxy-oxides. However the complex Cr(III) ions were bound to the sorbent surface via hydrogen bonds between the dye -OH groups and =O of the sorbent functional groups. The equation parameters of sorption isotherms indicate cooperative heterogeneous adsorption at low Cr(III) concentrations and chemisorption at high Cr(III) concentrations
    Źródło:
    Environment Protection Engineering; 2014, 40, 1; 5-22
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

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