Browsing by Author "Sarbassov, Yerbol"

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    Characterization of solid char produced from pyrolysis of the organic fraction of municipal solid waste, high volatile coal and their blends
    (Elsevier, 2019-11-22) Tokmurzin, Diyar; Kuspangaliyeva, Botagoz; Aimbetov, Berik; Abylkhani, Bexultan; Inglezakis, Vassilis J.; Anthony, Edward J.; Sarbassov, Yerbol
    In this study, the organic fraction of municipal solid waste (Org-MSW) was blended with high-volatile coal (HVC) in proportions of 25/75%, 50/50%, 75/25% by weight. Pyrolysis of these mixtures was then investigated in a thermogravimetric analyzer (TGA) and a horizontal tube furnace under a nitrogen environment. The mass loss rate of samples, differential thermogravimetry (DTG) curves and kinetic analysis of the samples were compared for both blended and non-blended samples. Higher gas yields were seen with increasing pyrolysis temperature for both samples. In addition, the kinetic analysis indicated that the apparent activation energy values of org-MSW samples varied from 535 to 5284 kJ/kmol (over the temperature range of 100–887 °C), while the values for HVC were 247–962 kJ/kmol. The activation energy for HVC varied with temperature and the highest value of 2036 kJ/kmol was found in the temperature range of 336–490 °C. Comparable results were obtained between the TGA and fixed bed tests on the residual char fraction. The findings of this work will be very important in developing a co-firing technology for solid waste residuals and coal for energy production.
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    Characterization of tar generated from the mixture of municipal solid waste and coal pyrolysis at 800 oC
    (Elsevier, 2020-03-02) Tursunov, O.; Suleimenova, B.; Kuspangaliyeva, Botagoz; Inglezakis, Vassilis J.; Anthony, Edward J.; Sarbassov, Yerbol
    Nowadays, comprehensive perception of the tar characteristics generated from municipal solid waste (MSW) and coal to guide pyrolysis or gasification gas yield upgrading and cleaning has attracted massive research attention. In this study, MSW and coal samples were chosen as principal components. The mixture of these products was pyrolyzed in a horizontal tube furnace at 800 °C with a heating rate of 20 °C/min. The tar derived from the pyrolysis of this mixture was further studied. Gas chromatography–mass spectrometry (GC–MS)coupled with a trace GC and a nuclear magnetic resonance (NMR) spectrometer was applied to investigate the tar composition and characterization along with their molecular chemical structures. 1H and 13C NMR spectra indicated that the functional groups of the tar derived from the mixture of MSW and coal were dominant at the resonances of 0.9–1.8 ppm, 1.5–2.6 ppm and 3.8–4.1 ppm for 1H, 10–40 ppm and 60–80 ppm for 13C. The results from GC–MS showed that the tar derived from the mixture of MSW and coal contained about 20 major chemical compounds such as benzene, methyl isobutyl, toluene, xylene, phenol, cresol, naphthalene and others.
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    Hydrodynamic experiments on a small-scale circulating fluidised bed reactor at elevated operating pressure, and under An O2/Co2 environment
    (VINCA Institute of Nuclear Sciences, 2017-03-01) Sarbassov, Yerbol; Zayoud, Azd; Mahanta, Pinakeswar; Gu, Sai; Ranganathan, Panneerselvam; Saha, Ujjwal
    Pressurised circulating fluidised bed (CFB) technology is a potentially promising development for clean coal technologies. The current work explores the hydrodynamics of a small-scale circulating fluidised bed at elevated operating pressures ranging from 0.10 to 0.25 MPa. The initial experiments were performed at atmospheric pressure with air and O/CO environments as the fluidisation gas to simulate the hydrodynamics in a CFB. A comparison between the effects of air and O/CO mixtures on the hydrodynamics was outlined in this paper for particles of 160 μm diameter. A small but distinct effect on axial voidage was observed due to the change in gas density in the dense zone of the bed at lower gas velocity, while only minimal differences were noticed at higher gas velocities. The hydrodynamic parameters such as pressure drop and axial voidage profile along the height were reported at two different bed inventories (0.5 and 0.75 kg) for three mean particle sizes of 160, 302 and 427 μm and three superficial gas velocities. It was observed that the operating pressure had a significant effect on the hydrodynamic parameters of bed pressure drop and axial bed voidage profiles. The effect of solids loading resulted in an exponential change in pressure drop profile at atmospheric pressure as well as at elevated pressure. The experimental results on hydrodynamic parameters are in reasonable agreement with published observations in the literature.
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    SO3 formation and the effect of fly ash in a bubbling fluidised bed under oxy-fuel combustion conditions
    (Elsevier, 2017-07-18) Sarbassov, Yerbol; Duan, Lunbo; Jeremias, Michal; Manovic, Vasilije; Anthony, Edward J.
    This study investigates the formation of SO3 under air and oxy-fuel combustion environments in a bench-scale bubbling fluidized bed. Flue gas compositions typical of air and oxy-fuel environments were simulated by bottle gases. Parameters such as bed temperature, SO2, O2 and H2O concentrations were varied to determine their effect on the formation of SO3 in both tests with fly ash acting as a catalyst catalyzed and uncatalyzed tests. Catalytic tests were conducted by adding three different fly ashes generated from three different coals. Experimental results support the expectation of show increased SO3 concentration for oxy-fuel combustion environments compared to typical air-fired environments. SO3 concentrations increased with combustion temperature, O2 and H2O concentrations. Catalytic tests have shownshowed that the formation of SO3 depends on the chemical composition of the fly ash, while unburnt carbons in the ash tend to reduce SO3 concentrations.
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    Sulfur trioxide formation/emissions in coal‐fired air‐ and oxy‐fuel combustion processes: a review
    (Wiley, 2018-03-22) Sarbassov, Yerbol; Duan, Lunbo; Manovic, Vasilije; Anthony, Edward J.
    In oxy‐fuel combustion, fuel is burned using oxygen together with recycled flue gas, which is needed to control the combustion temperature. This leads to higher concentrations of sulfur dioxide and sulfur trioxide in the recycled gas, which can result in the formation of sulfuric acid and enhanced corrosion. Current experimental data on SO3 formation, reaction mechanisms, and mathematical modelling have indicated significant differences in SO3 formation between air‐ and oxy‐fuel combustion for both the wet and dry flue gas recycle options. This paper provides an extensive review of sulfur trioxide formation in air‐ and oxy‐fuel combustion environments, with an emphasis on coal‐fired systems. The first part summarizes recent findings on oxy‐fuel combustion experiments, as they affect sulfur trioxide formation. In the second part, the review focuses on sulfur trioxide formation mechanisms, and the influence of catalysis on sulfur trioxide formation. Finally, the current methods for measuring sulfur trioxide concentration are also reviewed along with the major difficulties associated with those measurements using data available from both bench‐ and pilot‐scale units.