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Öğe Co-combustion of Zn/Cd-hyperaccumulator and textile dyeing sludge: Heavy metal immobilizations, gas-to-ash behaviors, and their temperature and atmosphere dependencies(Elsevier, 2023) Wu, Xieyuan; Chen, Zhiliang; Liu, Jingyong; Wei, Zebin; Chen, Zihong; Evrendilek, Fatih; Sun, Shuiyu; Chen, ZhibinThis study quantified and revealed the temperature and atmosphere dependencies of the enrichment rates and speciation distributions of Zn and Cd and the behaviors of Cl and S for the co-combustion of a hyperaccumulator (SAH) of Zn and Cd and textile dyeing sludge (TDS) at a blend ratio of 3:1 (ST31). The addition of Al-rich TDS to SAH provided the chemisorption sites for Zn and Cd and generated stable Al/Si structures for their stabilization in the ST31 ash. The rising temperature and the atmosphere change from N-2/O-2 to CO2/O-2 transformed Zn and Cd into their oxidizable and residual fractions. Cl promoted the volatilizations of the heavy metals, with its content in the ST31 ash falling from 86.28% at 650 ? to 17.98% at 950 ?. The S content (31.08-33.86%) of the ST31 ash existed mainly as CaSO4 and was slightly higher in the CO2/O-2 than N-2/O-2 atmosphere (29.45%) since the high CO2 concentration adversely influenced the decomposition of CaCO3, while S indirectly affected the migrations of Zn and Cd. The combined results of the experiments, thermodynamic simulations, and multi-objective optimization pointed to 850 ? in the oxy-fuel atmosphere with 30% O-2 concentration as the optimal settings in order to stabilize Zn and Cd with an acceptable risk. The possible reaction pathways and immobilization mechanisms were also derived considering the interactions among minerals, Zn, Cd, Cl, and S.Öğe Co-combustion of Zn/Cd-hyperaccumulator and textile dyeing sludge: Heavy metal immobilizations, gas-to-ash behaviors, and their temperature and atmosphere dependencies(Elsevier Science Sa, 2023) Wu, Xieyuan; Chen, Zhiliang; Liu, Jingyong; Wei, Zebin; Chen, Zihong; Evrendilek, Fatih; Sun, ShuiyuThis study quantified and revealed the temperature and atmosphere dependencies of the enrichment rates and speciation distributions of Zn and Cd and the behaviors of Cl and S for the co-combustion of a hyperaccumulator (SAH) of Zn and Cd and textile dyeing sludge (TDS) at a blend ratio of 3:1 (ST31). The addition of Al-rich TDS to SAH provided the chemisorption sites for Zn and Cd and generated stable Al/Si structures for their stabilization in the ST31 ash. The rising temperature and the atmosphere change from N-2/O-2 to CO2/O-2 transformed Zn and Cd into their oxidizable and residual fractions. Cl promoted the volatilizations of the heavy metals, with its content in the ST31 ash falling from 86.28% at 650 ? to 17.98% at 950 ?. The S content (31.08-33.86%) of the ST31 ash existed mainly as CaSO4 and was slightly higher in the CO2/O-2 than N-2/O-2 atmosphere (29.45%) since the high CO2 concentration adversely influenced the decomposition of CaCO3, while S indirectly affected the migrations of Zn and Cd. The combined results of the experiments, thermodynamic simulations, and multi-objective optimization pointed to 850 ? in the oxy-fuel atmosphere with 30% O-2 concentration as the optimal settings in order to stabilize Zn and Cd with an acceptable risk. The possible reaction pathways and immobilization mechanisms were also derived considering the interactions among minerals, Zn, Cd, Cl, and S.Öğe Co-combustion, life-cycle circularity, and artificial intelligence-based multi-objective optimization of two plastics and textile dyeing sludge(ELSEVIER, 2022) Ding, Ziyi; Chen, Zihong; Liu, Jingyong; Evrendilek, Fatih; He, Yao; Xie, WumingGiven the globally abundant availability of waste plastics and the negative environmental impacts of textile dyeing sludge (TDS), their co-combustion can effectively enhance the circular economies, energy recovery, and environmental pollution control. The (co-)combustion performances, gas emissions, and ashes of TDS and two plastics of polypropylene (PP) and polyethylene (PE) were quantified and characterized. The increased blend ratio of PP and PE improved the ignition, burnout, and comprehensive combustion indices. The two plastics interacted with TDS significantly in the range of 200-600 degrees C. TDS pre-ignited the combustion of the plastics which in turn promoted the combustion of TDS. The co-combustions released more CO2 but less CH4, C-H, and C--O as CO2 was less persistent than the others in the atmosphere. The Ca-based minerals in the plastics enhanced S-fixation and reduced SO2 emission. The activation energy of the co-combustion fell from 126.78 to 111.85 kJ/mol and 133.71-79.91 kJ/mol when the PE and PP additions rose from 10% to 50%, respectively. The co-combustion reaction mechanism was best described by the model of f(alpha) = (1-alpha)n. The reaction order was reduced with the additions of the plastics. The co-combustion operation interactions were optimized via an artificial neural network so as to jointly meet the multiple objectives of maximum energy production and minimum emissions.Öğe Dynamic pyrolysis behaviors, products, and mechanisms of waste rubber and polyurethane bicycle tires(Elsevier, 2021) Tang, Xiaojie; Chen, Zihong; Liu, Jingyong; Chen, Zhiyun; Xie, Wuming; Evrendilek, Fatih; Büyükada, MusaGiven their non-biodegradable, space-consuming, and environmentally more benign nature, waste bicycle tires may be pyrolyzed for cleaner energies relative to the waste truck, car, and motorcycle tires. This study combined thermogravimetry (TG), TG-Fourier transform infrared spectroscopy (TG-FTIR), and pyrolysis-gas chromato-graphy/mass spectrometry (Py-GC/MS) analyses to dynamically characterize the pyrolysis behavior, gaseous products, and reaction mechanisms of both waste rubber (RT) and polyurethane tires (PUT) of bicycles. The main devolatilization process included the decompositions of the natural, styrene-butadiene, and butadiene rubbers for RT and of urethane groups in the hard segments, polyols in the soft segments, and regenerated isocyanates for PUT. The main TG-FTIR-detected functional groups included C-H, C=C, C=O, and C-O for both waste tires, and also, N-H and C-O-C for the PUT pyrolysis. The main Py-GC/MS-detected pyrolysis products in the decreasing order were isoprene and D-limonene for RT and 4, 4 '-diaminodiphenylmethane and 2-hexene for PUT. The kinetic, thermodynamic, and comprehensive pyrolysis index data verified the easier decomposition of PUT than RT. The pyrolysis mechanism models for three sub-stages of the main devolatilization process were best described by two-dimensional diffusion and two second-order models for RT, and the three consecutive reaction-order (three-halves order, first-order, and second-order) models for PUT.Öğe Emission-to-ash detoxification mechanisms of co-combustion of spent pot lining and pulverized coal(Elsevier, 2021) Chen, Zihong; Liu, Jingyong; Chen, Laiguo; Evrendilek, Fatih; Xie, Wuming; Wu, XieyuanIn response to the global initiative for greenhouse gas emission reduction, the co-combustion of coal and spent pot lining (SPL) may cost-effectively minimize waste streams and environmental risks. This study aimed to quantify the emission-to-ash detoxification mechanisms of the co-combustion of SPL and pulverized coal (PC) and their kinetics, gas emission, fluorine-leaching toxicity, mineral phases, and migrations. The main reaction covered the ranges of 335-540 ?C and 540-870 ?C while the interactions occurred at 360-780 ?C. The apparent activation energy minimized (66.99 kJ/mol) with 90% PC addition. The rising PC fraction weakened the peak intensity of NaF and strengthened that of Ca2F, NaAlSiO4, and NaAlSi2O6. The addition of PC enhanced the combustion efficiency of SPL and raised the melting temperature by capturing Na. PC exhibited a positive effect on solidifying water-soluble fluorine and stabilizing alkali and alkaline earth metals. The leaching fluorine concentrations of the co-combustion ashes were lower than did SPL mono-combustion. The main gases emitted were HF, NH3, NOx, CO, and CO2. HF was largely released at above 800 ?C. Multivariate Gaussian process modelbased optimization of the operational conditions also verified the gas emissions results. Our study synchronizes the utilization and detoxification of SPL though co-combustion and provides insights into an eco-friendlier lifecycle control on the waste-to-energy conversion.Öğe Gas-to-ash detoxification feasibility and pathways by co-combustion of spent pot lining and food waste shells(Elsevier Science Ltd, 2022) Chen, Zihong; Liu, Jingyong; Wu, Xieyuan; Liu, Weizhen; Zhang, Gang; Evrendilek, FatihSeeking substitutions for Ca-bearing reagents, this study explored the synergistic co-disposal and co-circularity of spent pot lining (SPL) and food waste shells (oyster, clam, and egg shells) in an eco-friendly way. This study is first to evaluate the feasibility of their co-combustions with or without their mechanochemical activation (MCA) toward the gas-to-ash detoxification of fluorine (F). 50% calcined oyster shell fixed about 97.87% of the F content of SPL in the blend ash and outperformed 50% CaO. MCA weakened the diffraction peaks of graphite carbon by favoring the fixation performance through which collisions between particles and the mixing uni-formity were promoted. The combination of 10% SiO2 and 40% calcined clam or egg shells raised the F fixation rate to 98.72 and 99.23%, respectively. F was converted to the complex F-Si-Ca compounds rather than to CaF2. Ca and Si compounds facilitated stabilizing F and Na synchronously and formed NaCa2SiO4F. The leaching F concentration of the ash was less than 100 mg/L, meeting the Chinese criterion (GB 5085.3-2007). The recycling of the food waste shells performed effectively in the cleaner disposal process of SPL by suppressing fluorine emissions.Öğe Oxy-fuel and air combustion performances and gas-to-ash products of aboveground and belowground biomass of Sedum alfredii Hance(ELSEVIER SCIENCE SA, 2021) Wu, Xieyuan; Wei, Zebin; Liu, Jingyong; Chen, Zihong; Evrendilek, FatihThe eco-friendly disposal choices of phytoremediation biomass still remain to be explored. This study characterized the combustions of Sedum alfredii Hance (SAH) in response to its aboveground (SAH-A) and belowground (SAH-B) parts, the oxy-fuel (CO2/O2) and air (N2/O2) atmospheres, temperature, and heating rate. The decomposition behaviors, gas-to-ash characteristics, thermo-kinetic parameters, and mineral transformations were quantified. In both atmospheres, the combustion performances were better for SAH-A than SAH-B at the same heating rate. In the range of 400.0-598.8 degrees C, the maximum mass loss rate of both samples obviously decreased and delayed with CO2 replacing N2 at the same oxygen concentration. The SAH-A and SAH-B combustions in both atmospheres emitted C- (CO2, CO, CH4, and small molecular organic substances) and N-containing (HCN and NH3) gases. In both atmospheres, the temperature dependency of the gas emissions remained the same. Both empirical indices and ternary phase diagrams indicated that both samples had a high deposition risk. Thermochemical equilibrium simulations were used to predict the slagging risk in response to ash mineral transformations. Our findings can provide new insights into the combustion dynamics of phytoremediation biomass and its effect on CO2 capture, utilization, and storage in mitigating climate change.Öğe Oxy-fuel co-combustion dynamics of phytoremediation biomass and textile dyeing sludge: Gas-to-ash pollution abatement(Elsevier, 2022) Wu, Xieyuan; Liu, Jingyong; Wei, Zebin; Chen, Zihong; Evrendilek, Fatih; Huang, WenxiaoThe environmental pressures of major wastes in the circular economies can be abated leveraging the complementarity and optimal conditions of their co-combustion. The oxy-fuel co-combustion of phytoremediation biomass of Sedum alfredii Hance (SAH) and textile dyeing sludge (TDS) may be a promising choice for sustainable CO2 capture and a waste-to-energy conversion. This study characterized and quantified their co-combustion performances, kinetics, and interactions as a function of blend ratio, atmosphere type, and temperature. With a focus on the characteristic el-ements of SAH (Ca, K, Zn, and Cd) and TDS (Al and S), changes in the mineral phases and ash melting and slagging trends of K2O-Al2O3-SiO2 and CaO-Al2O3-SiO2 systems were quantified. The Zn and Cd residual rates of the co-combustion of 75% SAH and 25% TDS rose by 58.52% and 5.93%, respectively, in the oxy-fuel atmosphere at the 30% oxygen concentration, relative to the mono-combustion of SAH in the air atmosphere. The co-combustion in the oxy-fuel atmosphere at the 20% oxygen concentration delayed the release peaks of SO2, C2S, and H2S, while the Ca-rich SAH captured S in TDS through the formation of CaSO4. Our findings provide new and practical insights into the oxy-fuel co-combustion toward the enhanced co-circularity.Öğe Water-soluble fluorine detoxification mechanisms of spent potlining incineration in response to calcium compounds(Elsevier Sci Ltd, 2020) Zhang, Gang; Sun, Guang; Chen, Zihong; Evrendilek, Fatih; Liu, JingyongIn this study, the detoxification mechanisms of water-soluble fluorine in the bottom ash and the distribution of fluorine during the spent potlining (SPL) incineration were characterized in response to four calcium compounds using an experimental tube furnace. CaSiO3, CaO, Ca(OH)(2), and CaCO3-assisted SPL incineration converted NaF to low toxicity compounds in the bottom ash yielding a conversion range of 54.24-99.45% relative to the individual SPL incineration. The two main mechanisms of the fluorine transformation were the formations of CaF2 and Ca4Si2O7F2. The fluorine transformation efficiency was greater with CaSiO3 than CaO, Ca(OH)(2), and CaCO3. Our simulations demonstrated that SiO2 enhanced the conversion of NaF. The fluorine leaching content of the bottom ash was estimated at 13.71 mg,L-1 after the SPL co-incineration with CaSiO3 (Ca:F = 1.2:1). The acid-alkali solutions had no significant effect on the fluorine leaching content of the bottom ash when 3 <= pH <= 12. Fluorine during the SPL co-incineration with CaSiO3 (Ca:F = 1.2:1) at 850 degrees C for 60 min was partitioned into 83.37, 13.90, and 2.72% in the bottom ash, fly ash, and flue gas, respectively. The transformation and detoxification mechanisms of water-soluble fluorine provide new insights into controls on fluorine emission from the SPL incineration. (C) 2020 Elsevier Ltd. All rights reserved.
