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    (Co-)combustion of additives, water hyacinth and sewage sludge: thermogravimetric, kinetic, gas and thermodynamic modeling analyses
    (Pergamon-Elsevier Science Ltd, 2018) Liu, Jingyong; Huang, Limao; Sun, Guang; Chen, Jiacong; Zhuang, Shengwei; Büyükada, Musa; Evrendilek, Fatih
    Additives and biomass were co-combusted with sewage sludge (SS) to promote SS incineration treatment and energy generation. (Co-)combustion characteristics of sewage sludge (SS), water hyacinth (WH), and 5% five additives (K2CO3, Na2CO3, Mg2CO3, MgO and Al2O3) were quantified and compared using thermogravimetric-mass spectrometric (TG-MS) and numerical analyses. The combustion performance of SS declined slightly with the additives which was demonstrated by the 0.03-to-0.25-fold decreases in comprehensive combustibility index (CCI). The co-combustion performed well given the 0.31-fold increase in CCI. Kinetic parameters were estimated using the Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) methods. Apparent activation energy estimates by OFW and KAS were consistent. The addition of K2CO3 and MgCO3 decreased the weighted average activation energy of SS. Adding K2CO3 to the blend reduced CO2, NO2, SO2, HCN and NH3 emissions. CO2, NO2 and SO2 emissions were higher from WH than SS. Adding WH or K2CO3 to SS increased CO2, NO2 and SO2 but HCN and NH3 emissions. Based on both catalytic effects and evolved gases, K2CO3 was potentially an optimal option for the catalytic combustion among the tested additives. (C) 2018 Elsevier Ltd. All rights reserved.
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    Co-combustion of sewage sludge and coffee grounds under increased O-2/CO2 atmospheres: Thermodynamic characteristics, kinetics and artificial neural network modeling
    (Elsevier Sci Ltd, 2018) Chen, Jiacong; Xie, Candie; Liu, Jingyong; He, Yao; Xie, Wuming; Zhang, Xiaochun; Chang, Kenlin; Büyükada, Musa; Evrendilek, Fatih
    (Co-)combustion characteristics of sewage sludge (SS), coffee grounds (CG) and their blends were quantified under increased O-2/CO2 atmosphere (21, 30, 40 and 60%) using a thermogravimetric analysis. Observed percentages of CG mass loss and its maximum were higher than those of SS. Under the same atmospheric O-2 concentration, both higher ignition and lower burnout temperatures occurred with the increased CG content. Results showed that ignition temperature and comprehensive combustion index for the blend of 60% SS-40% CG increased, whereas burnout temperature and co-combustion time decreased with the increased O-2 concentration. Artificial neural network was applied to predict mass loss percent as a function of gas mixing ratio, heating rate, and temperature, with a good agreement between the experimental and ANN-predicted values. Activation energy in response to the increased O-2 concentration was found to increase from 218.91 to 347.32 kJ.mol(-1) and from 218.34 to 340.08 kJ.mol(-1) according to the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods, respectively.
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    Co-pyrolytic mechanisms, kinetics, emissions and products of biomass and sewage sludge in N-2, CO2 and mixed atmospheres
    (Elsevier Science Sa, 2020) Chen, Jiacong; Zhang, Junhui; Liu, Jingyong; He, Yao; Evrendilek, Fatih; Büyükada, Musa; Xie, Wuming
    The co-pyrolysis technology of the second-generation feedstocks has both engineering and environmental advantages towards resource recovery, waste stream reduction, and energy generation. However, there exists a large knowledge gap about the co-pyrolytic mechanisms, kinetics, emissions and products of biomass wastes. This study aimed to quantify the co-pyrolytic interactions between the five (N-2, CO2, and three mixed) atmospheres and the two feedstocks of sewage sludge (SS) and coffee grounds (CG) as well as their emissions and products. Thermogravimetric-Fourier transform infrared spectrometry, two-dimensional correlation spectroscopy and pyrolysis-gas chromatography/mass spectrometry analyses were combined. An eight-parallel distributed activation energy model was adopted to elucidate the dynamic reaction mechanisms in the co-pyrolytic atmospheres. The co-pyrolytic interaction changed the maximum weight loss rate of the first peak by -2.5 to 38.6% and -1.9 to 36.9% in the N-2 and CO2 atmospheres, respectively. The mass loss rate peak in the first stage was higher in the N-2 than CO2 and mixed atmospheres, while the peak temperature of the maximum mass loss rate in the second stage declined with the elevated CO2 concentration. The replacement of N-2 with the different CO2 concentrations significantly increased the activation energies of the 5th and 7th pseudo-components. The temperature dependency of evolved gases was of the following order: ethers/esters -> acids/ketones/aldehydes/CO2 -> hydrocarbons in the N-2 atmosphere, and acids/ketones/aldehydes -> esters/ethers -> hydrocarbons in the CO2 atmosphere. The co-pyrolysis improved the yields of the hydrocarbon and phenol-type compounds and reduced the formations of the acid and nitrogenous compounds. Our results yielded valuable insights into a cleaner co-pyrolysis process.
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    Combustion behaviors of spent mushroom substrate using TG-MS and TG-FTIR: thermal conversion, kinetic, thermodynamic and emission analyses
    (Elsevier Sci Ltd, 2018) Huang, Jianli; Liu, Jingyong; Chen, Jiacong; Xie, Wuming; Kuo, Jiahong; Büyükada, Musa; Evrendilek, Fatih
    The present study systematically investigated the combustion characteristics of spent mushroom substrate (SMS) using TG-MS (thermogravimetric/mass spectrometry) and TG-FTIR (thermogravimetric/Fourier transform infrared spectrometry) under five heating rates. The physicochemical characteristics and combustion index pointed to SMS as a promising biofuel for power generation. The high correlation coefficient of the fitting plots and similar activation energy calculated by various methods indicated that four suitable iso-conversional methods were used. The activation energy varied from 130.06 to 192.95 kJ/mol with a mean value of 171.49 kJ/ mol using Flynn-Wall-Ozawa and decreased with the increased conversion degree. The most common emissions peaked at the range of 200-400 degrees C corresponding to volatile combustion stage, except for CO2, NO2 and NO. The peak CO2 emission occurred at 439.11 degrees C mainly due to the combustion of fixed carbon.
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    Coupled mechanisms of reaction kinetics, gas emissions, and ash mineral transformations during combustion of AlCl3-conditioned textile dyeing sludge
    (Elsevier, 2021) Zhang, Junhui; Chen, Jiacong; Liu, Jingyong; Xie, Wuming; Evrendilek, Fatih; Li, Weixin
    Though commonly used in the dewatering of textile dyeing sludge (TDS) before its incineration, chemical conditioning has yet to be evaluated in terms of its impact on the reaction mechanisms, emissions, and ash minerals. This study combined experiments and equilibrium simulations to disentangle the interaction mechanism among the combustion behaviors, gas emissions, ash minerals of TDS conditioned with(out) three blend ratios of the AlCl3 conditioner. The use of the AlCl3 conditioner slightly improved the performance of the combustion stage of volatiles and chars. No significant effect of AlCl3 conditioner was detected on the kinetic mechanism of its main combustion stage best elucidated by the nth-order and diffusion models. SO2 was the main evolved gas whose reduction between 600 and 800 degrees C was attributed to its increased retention rate by CaO from the decomposition of CaCO3. Aluminum compounds acted as a stimulator in SO2 emission between 800 and 1000 degrees C since the formation of calcium aluminosilicates. At above 1060 degrees C, CaSO4 decomposed rapidly, thus almost completely releasing inorganic S. This study supplies new insights into pollution 'controls on the combustion of TDS conditioned with Al salt coagulant.
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    Fates of heavy metals, S, and P during co-combustion of textile dyeing sludge and cattle manure
    (Elseiver, 2023) Zhang, Junhui; Chen, Jiacong; Liu, Jingyong; Evrendilek, Fatih; Zhang, Gang; Chen, Zhibin
    The co-combustion of textile dyeing sludge (TDS) and cattle manure (CM) may enhance circularity in terms of resource and pollution controls. However, the pollutant migrations and transformations of ashes and their characterization during the co-combustion are still unclear. This study aimed to quantify the transformation and migration behaviors of the co-combustion ashes, as well as the interactions involved via thermogravimetric experiments and thermodynamic simulations. The addition of TDS facilitated the conversions of Ni and Cr from the extractable form to the stable one, increasing their environmental safety. P dominated S for the reaction with Ca which promoted the generation of S-containing gas emission and apatite P. The reactions between the minerals in CM and Ca in TDS generated calcium silicate, decreasing the S-fixation ability of Ca, while increasing the emission of S-containing gases. Our findings provide insights into the interactions among the minerals, the heavy metals, and the specific elements and their impacts on pollutant emissions, thus enhancing pollution control strategies.
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    The mixture of sewage sludge and biomass waste as solid biofuels: Process characteristic and environmental implication
    (Pergamon-Elsevier Science Ltd, 2019) Chen, Jiacong; He, Yao; Liu, Jingyong; Liu, Chao; Xie, Wuming; Büyükada, Musa; Evrendilek, Fatih
    Oxy-fuel and air atmospheres were used to (co-)combust sewage sludge (SS) and biomass waste, coffee ground residues (CG) via thermogravimetric analysis (TGA). The combustion behavior of SS did not differ significantly in both atmospheres. The replacement of 79%N-2 by 79%CO2 significantly influenced the char combustion of CG. Synergistic effect of the blends in the oxy-fuel was weaker than air condition. Activation energy of the co-combustion in the second stage was lower in the oxy-fuel than air atmosphere. The gaseous emissions during blend fuel combustion were investigated by online mass spectrometry (MS). Results show that the gas emissions of different fuels show different stage characteristics. CH3, H2O, C2H2 and NO emissions peaked from the volatiles combustion of CG, while the co-combustion led to SO2 increment. Besides, the composition of the solid residues was examined by X-ray fluorescence spectrometer (XRF), and their impact on environment was evaluated. The compositions of the solid residues pointed to the ability of SS to lower the fouling and slagging risks of CG. This investigation aimed to afford a fully understanding for the co-combustion progress of SS and CG under air and oxy-fuel environments and its implication for environment. (C) 2019 Elsevier Ltd. All rights reserved.