Yazar "Yan, Youping" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Catalytic combustions of two bamboo residues with sludge ash, CaO, and Fe2O3: Bioenergy, emission and ash deposition improvements(Elsevier Sci Ltd, 2020) Hu, Jinwen; Yan, Youping; Song, Yueyao; Liu, Jingyong; Evrendilek, Fatih; Büyükada, MusaThe catalytic combustions of bamboo leaves (BL) and branches (BB) with textile dyeing sludge ash (SA), Fe2O3, and CaO were qualitatively analyzed using thermogravimetric and Fourier transform infrared spectroscopy analyses, and thermodynamic equilibrium simulations. The catalysts (Fe2O3 > SA > CaO) exerted a more pronounced effect in the char combustion (third) stage and enhanced the volatiles and comprehensive combustion indices with 40 degrees C/min. The catalysts (CaO > SA > Fe2O3) reduced C- and N-containing gas emissions in the devolatilization (second) stage. CaO elevated the N-containing gas emission in the third stage, whereas Fe2O3 and SA inhibited the formation of NO precursors. BB presented a higher risk of slagging than did BL, while the improved empirical indices of the ash deposition pointed to CaO as the optimal catalyst. Our simulations showed the final ash components of BL and BB were mainly as SiO2 and K2Si4O9. The addition of CaO alone helped to form a high-melting point Ca-silicate. Although the addition of Fe2O3 had no effect on the ash conversion, SA reduced the formation of K-silicate in the ash. The catalysts (CaO > SA > Fe2O3) reduced the activation energy. Overall, the catalytic combustions improved the bioenergy and the N-containing gas emissions. SA as a Fe and Ca-rich industrial waste enhanced the combustion performance in terms of reductions in waste streams, gas emissions, and ash deposition. Our results supplied new insights into the efficient and clean bioenergy production of bamboo residues, and the waste utilization of SA. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Combustion behaviors of three bamboo residues: Gas emission, kinetic, reaction mechanism and optimization patterns(Elsevier Sci Ltd, 2019) Hu, Jinwen; Yan, Youping; Evrendilek, Fatih; Büyükada, Musa; Liu, JingyongThis study focused on the assessment of gas emissions and bioenergy potential of the combustions of bamboo leaves (BL), shoot leaves (BSL) and branches (BB) in the air atmosphere. The main combustion stage of the three residues occurred at between 200 and 600 degrees C, with three peaks of mass loss. The pattern of mass loss rate was BSL > BB > BL, with BSL having the best combustion characteristic parameters. The main evolved gases were CO2 and H2O at between 200 and 600 degrees C. Organic gaseous compounds were decomposed in the range of 200-400 degrees C. Air pollutants were produced in the range of 200-500 degrees C. N-containing gas pollutants were 0.01-0.1 times CO2, while SO2 was produced in a very small amount. BL produced more gas pollutants than did BSL and BB, while the controls over the gas pollutants should be more concentrated in the range of 200-400 degrees C. The joint optimizations of derivative thermogravimetry, differential scanning calorimetry, remaining mass, and conversion degree showed 653.2 degrees C and 5 degrees C/min as the optimum operational conditions for bioenergy utilization, while BB performed as the best feedstock. Among three iso-conversion methods used to estimate activation energy, Flynn-Wall-Ozawa led to best correlation. The Coats-Redfern method pointed to the second order reaction model (f (alpha) = (1-alpha)(2)) as the most likely reaction mechanism. Overall, the bamboo residues were promising as the environmentally friendly and renewable feedstock. Our findings can provide the basis for bioenergy generation, pollution control, and optimal efficiency when the industrial-scale combustions of the bamboo residues are adopted. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Combustions of torrefaction-pretreated bamboo forest residues: Physicochemical properties, evolved gases, and kinetic mechanisms(Elsevier Sci Ltd, 2020) Hu, Jinwen; Song, Yueyao; Liu, Jingyong; Evrendilek, Fatih; Büyükada, Musa; Yan, Youping; Li, LeiUnlike light torrefaction at 200 degrees C (B200), the mild (250 degrees C) and severe (300 degrees C) torrefaction pretreatments (B250 and B300) significantly increased the calorific value, reduced the oxygen content and improved the surface morphology for bamboo residues (BR). The main oxygen-removing carriers of BR during torrefaction were CO2 and carbonyl compounds. Their torrefaction delayed the start and burnout temperatures of the BR combustions, increased CO2 emission and decreased NH3 and NO emissions significantly. The torrefaction reduced their activation energy in zone II (200-350 degrees C) and led to a transition from a nucleation to a diffusion mechanism. All the combustions in zone III (350-500 degrees C) were best explained by a reaction order model whose order rose with the elevated torrefaction temperature. Overall, BR appeared to be more suitable for the torrefaction at 250-300 degrees C. Our results can provide practical insights into how to turn BR into efficient and clean bioenergy.Öğe Pyrolysis performance, kinetic, thermodynamic, product and joint optimization analyses of incense sticks in N-2 and CO2 atmospheres(Pergamon-Elsevier Science Ltd, 2019) Wen, Shaoting; Yan, Youping; Liu, Jingyong; Büyükada, Musa; Evrendilek, FatihThermogravimetric and pyrolysis-gas chromatography/mass spectrometry analyses were performed to quantify the pyrolysis performances, kinetics, thermodynamics, products and optimization of incense sticks (IS) in N-2 and CO2 atmospheres at five heating rates. The increased heating rate caused a lagged IS pyrolysis, moving its curves to a higher temperature. According to four model-free methods, activation energy estimates ranged from 34.17 to 439.19 kJ.mol(-1) and 28.46-187.34 kJ.mol(-1) in the N-2 and CO2 atmospheres, respectively. The three-dimension diffusion (spherical symmetry) (D3) was determined using the Horowitz-Metzger method as the most probable degradation mechanism in both atmospheres. The main pyrolytic products were found as benzene and its derivatives whose mass accounted for 49.94% of the total 18 products. Significant two-way interaction effects were found between temperature, heating rate, and atmosphere type on the three responses of remaining mass, derivative thermogravimetry, and differential scanning calorimetry (p = 0.001). The best joint optimization was obtained at 899.5 degrees C with the heating rate of 5 degrees C.min(-1) in the CO2 atmosphere and was more sensitive to the increased heating rate in the N-2 than CO2 atmosphere. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Synergistic effects, gaseous products, and evolutions of NOx, precursors during (co-)pyrolysis of textile dyeing sludge and bamboo residues(Elsevier, 2021) Hu, Jinwen; Song, Yueyao; Liu, Jingyong; Evrendilek, Fatih; Büyükada, Musa; Yan, YoupingThis study aimed to investigate the synergistic influences of the textile dyeing sludge (TDS) and bamboo residues (BR) co-pyrolysis, and its effects on the formation mechanisms of NH3 and HCN. The mass loss rate was lower for TDS than BR, with the co-pyrolysis with 50% BR exerting the strongest synergistic effect. The pyrolysis stages 1 (< 400 degrees C) and 2 (400 800 degrees C) were best described using the diffusion and third-order reaction mechanisms, respectively. Activation energy and frequency factor were lower for the pyrolysis of TDS than BR. The addition of no less than 50% BR significantly increased the emissions of CO2, CO, CH4, C=O, and C O and reduced the aromatic compounds. The thermal stability of N-A structure was lower in TDS than BR. The co-pyrolysis with 50% BR significantly inhibited the formations of NH3 and HCN and improved the aromaticity of biochar. This may due to the weakened hydrogenation reaction at N sites, the enhanced conversion of NH3, the inhibition of the ring cleavage in the char-secondary cracking, and the formation of more quaternary-N. Our results provide insights into the co-treatment of TDS and BR, and controls over NO,, precursors for a cleaner energy production.
