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Öğe Ash-to-emission pollution controls on co-combustion of textile dyeing sludge and waste tea(Elseiver, 2021) Cai, Haiming; Liu, Jingyong; Kuo, Jiahong; Xie, Wuming; Evrendilek, Fatih; Zhang, GangGiven the globally increased waste stream of textile dyeing sludge (TDS), its co-combustion with agricultural residues appears as an environmentally and economically viable solution in a circular economy. This study aimed to quantify the migrations and chemical speciations of heavy metals in the bottom ashes and gas emissions of the co-combustion of TDS and waste tea (WT). The addition of WT increased the fixation rate of As from 66.70 to 83.33% and promoted the chemical speciation of As and Cd from the acid extractable state to the residue one. With the temperature rise to 1000 degrees C, the fixation rates of As, Cd, and Pb in the bottom ashes fell to 27.73, 8.38, and 15.40%, respectively. The chemical speciation perniciousness of Zn, Cu, Ni, Mn, Cr, Cd, and Pb declined with the increased temperature. The ash composition changed with the new appearances of NaAlSi3O8, CaFe2O4, NaFe(SO4)(2), and MgCrO4 at 1000 degrees C. The addition of WT increased CO2 and NOx but decreased SO2 emissions in the range of 680-1000 degrees C. ANN-based joint optimization indicated that the co-combustion emitted SO2 slightly less than did the TDS combustion. These results contribute to a better understanding of ash-to-emission pollution control for the co-combustion of TDS and WT. (C) 2021 Elsevier B.V. All rights reserved.Öğe Pyrolysis dynamics of two medical plastic wastes: Drivers, behaviors, evolved gases, reaction mechanisms, and pathways(Elsevier, 2021) Ding, Ziyi; Chen, Huashan; Liu, Jingyong; Cai, Haiming; Evrendilek, Fatih; Büyükada, MusaThe public has started to increasingly scrutinize the proper disposal and treatment of rapidly growing medical wastes, in particular, given the COVID-19 pandemic, raised awareness, and the advances in the health sector. This research aimed to characterize pyrolysis drivers, behaviors, products, reaction mechanisms, and pathways via TG-FTIR and Py-GC/MS analyses as a function of the two medical plastic wastes of syringes (SY) and medical bottles (MB), conversion degree, degradation stage, and the four heating rates (5,10, 20, and 40 degrees C/min). SY and MB pyrolysis ranged from 394.4 to 501 and from 417.9 to 517 degrees C, respectively. The average activation energy was 246.5 and 268.51 kJ/mol for the SY and MB devolatilization, respectively. MB appeared to exhibit a better pyrolysis performance with a higher degradation rate and less residues. The most suitable reaction mechanisms belonged to a geometrical contraction model (R-2) for the SY pyrolysis and to a nucleation growth model (A(1.2)) for the MB pyrolysis. The main evolved gases were C-4-C-24 alkenes and dienes for SY and C-6-C-41 alkanes and C-8 -C-41 alkenes for MB. The pyrolysis dynamics and reaction pathways of the medical plastic wastes have important implications for waste stream reduction, pollution control, and reactor optimization.Öğe Pyrolytic kinetics, reaction mechanisms and products of waste tea via TG-FTIR and Py-GC/MS(Pergamon-Elsevier Science Ltd, 2019) Cai, Haiming; Liu, Jingyong; Xie, Wuming; Kuo, Jiahong; Büyükada, Musa; Evrendilek, FatihThe present study experimentally quantified the pyrolysis behaviors of waste tea (WT) as a function of four heating rates using thermogravimetric-Fourier transform infrared spectrometry and pyrolysis-gas chromatography-mass spectrometry analyses. The maximum weight loss of WT (66.79%) occurred at the main stage of devolatilization between 187.0 and 536.5 degrees C. The average activation energy estimates of three sub-stages of devolatilization were slightly higher (161.81, 193.19 and 224.99 kJ/mol, respectively) by the Flynn-Wall-Ozawa than Kissinger-Akahira-Sunose method. Kinetic reaction mechanisms predicted using the master-plots were f (alpha) = (3/2)(1 - alpha)(2/3)[1 - (1 - alpha)(1/3)](-1), f (alpha) = (1 - alpha)(2), and f (alpha) = (1 - alpha)(2.5) for the three sub-stages, respectively. The prominent volatiles of the WT pyrolysis were CO2 > C=O > phenol > CH4 > CO > NH3 > H2O > CO. A total of 33 organic compounds were identified including alkene, acid, benzene, furan, ketone, phenol, nitride, alcohol, aldehyde, alkyl, and ester. This study provides a theoretical and practical guideline to meeting the engineering challenges of introducing WT residues in the bioenergy sector.Öğe Thermal characteristics, kinetics, gas emissions and thermodynamic simulations of (co-)combustions of textile dyeing sludge and waste tea(Elsevier Sci Ltd, 2019) Cai, Haiming; Liu, Jingyong; Kuo, Jiahong; Büyükada, Musa; Evrendilek, FatihThe thermal conversion of waste into energy is increasingly becoming an integral part of environmentally friendly and sustainable societies. In this study, the (co-)combustion behaviors, kinetics, and gas emissions of textile dyeing sludge (TDS) and waste tea (WT) were quantified. The addition of WT appeared to avoid the drawbacks of both TDS and WT and to enhance their combustion efficiency. The main co-combustion process was characterized by three stages. The WT addition led to higher reactivity and a better combustion performance. The average apparent activation energy reached its minimum (154.82 kJ/mol) with 40% WT. The reaction mechanisms of the three stages of the 40% WT blend were best described using the D2, F3 and F2.3 models, respectively. The interaction between TDS and WT occurred between 370 and 550 degrees C. The WT addition changed the peak strength of Fe2O3 and produced NaAlSiO4 and CaSO4 . The blend ash composition was found to consist of Fe2O3, CaSO4, Na2SO4, Ca5HP3O13, and NaAlSiO4 according to X-ray diffraction analysis and thermodynamic simulations. The WT addition reduced SO2 emission from the co-combustion. Our results can be benefited to provide pollution reduction, energy generation, performance improvement, scaling-up, and optimization for the industrial applications. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Thermal degradations and processes of waste tea and tea leaves via TG-FTIR: combustion performances, kinetics, thermodynamics, products and optimization(Elsevier Sci Ltd, 2018) Cai, Haiming; Zou, Huihuang; Liu, Jingyong; Xie, Wuming; Kuo, Jiahong; Büyükada, Musa; Evrendilek, FatihThe present study characterized the kinetic, thermodynamic and performance parameters, products, factorial interactions, and optimal conditions of combustions of waste tea (WT) and tea leaves (TL) in N-2/O-2 and CO2/O-2 atmospheres through a thermogravimetric/Fourier transform infrared spectrometry (TG-FTIR). The main combustion occurred in the range of 200-600 degrees C. The increased heating rate increased all the combustion parameters regardless of the fuel and atmosphere type. Activation energy was shown different change tendency with the increasing conversion (alpha). CO2, H2O, CH4, CO, C=O, NH3, and HCN were the main gas products of WT and TL combustions. A three-way interaction among fuel type, atmosphere type and heating rate was found to be significant. The joint optimization of mass loss, derivative TG, and differential scanning calorimetry was achieved using 1049.3 degrees C, TL, 40 degrees C/min, and CO2/O-2 atmosphere for the operational settings of temperature, fuel type, heating rate, and atmosphere type, respectively.Öğe Thermodynamic equilibrium predictions of zinc volatilization, migration, and transformation during sludge co-incineration(John Wiley and Sons Inc., 2019) Liu, Jingyong; Cai, Haiming; Wu, Shijun; Büyükada, Musa; Evrendilek, FatihThe effects of interactions between and among chlorine (Cl), sulfur (S), phosphorus (P), and minerals on migration, transformation, and volatilization of zinc (Zn) were numerically simulated in sludge co-incineration using the chemical thermodynamic equilibrium method. Our results showed that all the minerals of Fe2O3, Al2O3, Fe2O3, and TiO2 except for CaO in the sludge co-incineration system reacted with Zn which inhibited the Zn volatilization. The presence of S and P was beneficial to the formation of ZnSO4(s) and Zn3(PO4)2(s). Cl weakened the chemical reactions between the minerals and Zn, thus increasing the Zn volatilization. Changes in Zn transformation and migration induced by the coupling of Cl + S were mainly controlled by Cl, S, and the minerals, while those induced by Cl + P and S + P were mainly controlled by P and S + P. The presence of P + Cl, S + Cl, S + P, S + Cl + P, Cl, and Al2O3 in the coexisting mineral system controlled the reactions between the minerals and Zn. © 2018 Water Environment Federation.
