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Öğe (Co-)combustion behaviors and products of spent potlining and textile dyeing sludge(Elsevier Sci Ltd, 2019) Sun, Guang; Zhang, Gang; Liu, Jingyong; Xie, Wuming; Evrendilek, Fatih; Büyükada, MusaCo-combustion performances, ashes, gases and thermodynamics were quantified for spent potlining (SPL) and textile dyeing sludge (TDS) (with)out CaO. During the four decomposition stages of the blends according to the (D)TG experiments, the interaction among Na, Ca, F, Al, and S led to CaAl2O4, CaF2, and Na2SO4 which converted inorganic compounds into ash. Increased comprehensive combustion index, and decreased burnout temperature with 50% SPL indicated a better combustion and char burnout, and a shorter combustion process. CaO reduced the F volatilization and increased F- in the residual ash with 10% CaO. NaF was completely converted into CaF2 reducing the toxicity of soluble F- in the residual ash. The predom diagram of Na-Ca-F-S using thermal simulations showed the stable existence regions of CaF2 and Na2SO4. The changed migration mechanisms of F- and S caused ash compositions to consist of Na2SO4 and CaF2 for the co-combustions, and of NaF and CaSO4 for the mono-combustions. 10% CaO promoted CaF2, Na2SO4, CaAl2O4, and to a lesser extent, Fe2O3. The main gases evolved from the co-combustion included HF, SO2, COS, CS2, HCN, NH3, NO, and NO2. (C) 2019 Elsevier Ltd. All rights reserved.Öğe (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, FatihAdditives 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.Öğe Co-combustion of textile dyeing sludge with cattle manure: Assessment of thermal behavior, gaseous products, and ash characteristics(Elsevier Sci Ltd, 2020) Zhang, Junhui; Sun, Guang; Liu, Jingyong; Evrendilek, Fatih; Büyükada, MusaNot only can the incineration provide an effective waste stream reduction, but also it enhances the energy recovery. However, the combustion performance of textile dyeing sludge is poor due to its low combustible content and low calorific value. This study proposes to compensate for the defects by its co-combustion with cattle manure. The co-combustion exerted an inhibitive effect between 350 and 500 degrees C and a positive effect between 600 and 1100 degrees C on the thermal degradation. The strongest enhancement occurred with the blend ratio of 1:1. The co-combustion reduced the maximum SO2 emission and produced fewer gas species including CO2, CO, H2O, ketones, aldehydes, and low molecular weight chain-alkanes. The experimental and simulation results about mineral transformations showed that the blend ash consisted of SiO2, Fe2O3, CaMgSi2O6, NaAlSiO4, NaAlSi3O8, and Na2SO4. The blend ash had the lowest fusion temperature due to the formation of a low temperature eutectic. The findings provide insights into controls over gas emissions, energy recovery, and ash reutilization, essential to the development of cleaner and sustainable co-combustion systems. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Performance and mechanism of bamboo residues pyrolysis: Gas emissions, by-products, and reaction kinetics(Elseiver, 2022) Zhang, Gang; Feng, Qiuyuan; Hu, Jinwen; Sun, Guang; Evrendilek, Fatih; Liu, Hui; Liu, JingyongThe performances and reaction kinetics of the bamboo shoot leaves (BSL) pyrolysis were characterized integrating thermogravimetry, Fourier transform infrared spectroscopy, and pyrolysis-gas chromatography/mass spectrometry analyses. The high volatiles and low ash, N, and S contents of BSL rendered its pyrolysis suitable for bio-oil generation. The main mass loss of BSL pyrolysis occurred in the devolatilization stage between 200 and 550 C. The peak temperatures of pseudo-hemicellulose, cellulose and lignin pyrolysis in BSL were 248.04, 322.65 and 383.51 C, respectively, while their average activation energies estimated by Starink method were 144.29,175.79 and 243.02 kJ/mol, respectively. The one-dimensional diffusion mechanism (f (alpha) = 1/(2 alpha)) best elucidated the hemicellulose reaction. The cellulose (f (alpha) = 0.74 (1 - alpha)[-ln (1 - alpha)]-13/37) and lignin (f (alpha) = 0.35 (1 - alpha)[-ln (1 - alpha)]-13/7) reactions were best described by the nucleation mechanisms. The estimated kinetic triplets accurately predicted the pyrolysis process. 619.3 C and 5 C/min were determined as the optimal pyrolytic temperature and heating rate. The C-containing gases were dominant among the non-condensable gases evolved from the pyrolysis. The NO(x )precursors (NH3 and HCN) were found more important than NO emission in pollution control. 2,3-dihydrobenzofuran, (1-methylcyclopropyl) methanol, heptanal, acetic acid, and furfurals were the main pyrolytic by-products. BSL-derived biochar is a relatively pure carbon-rich material with extremely low N and S content. The BSL pyrolysis yielded a promising performance, as well as value-added by-products to be utilized in the fields of bioenergy, fragrance, and pharmaceuticals.Öğe Thermal behaviors of fluorine during (co-)incinerations of spent potlining and red mud: Transformation, retention, leaching and thermodynamic modeling analyses(Pergamon-Elsevier Science Ltd, 2020) Zhang, Gang; Sun, Guang; Liu, Jingyong; Evrendilek, Fatih; Büyükada, Musa; Xie, WumingSpent potlining (SPL) as a hazardous solid waste has a high content of inorganic fluorine. This study aimed at characterizing its transformation, retention and leaching behaviors with(out) the addition of red mud (RM) during the SPL incineration. The RM addition positively affected its retention and leaching rates. Its Ca-containing compounds caused Na3AlF6 and NaF to turn into more CaF2. 30% RM converted water-soluble NaF into more stable CaF2 than did SPL at 850 degrees C, thus reducing the leaching rate by 45.15%. 30% RM captured HF through its Ca content and enhanced its retention rate by 66.96%. 66.01% of the total fluorine was stably retained in the bottom ash, and thus, significantly reduced the toxicity of the SPL incineration products. SiO2 and Al2O3 exerted a thermally positive effect on NaF turning into CaF2. The fluoride retention of the bottom ash was mainly dominated by CaF2 and NaF with(out) RM. Smaller, coarser and more loose structures of the co-incinerated solid particles pointed to a synergistic interaction between SPL and RM. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Thermal behaviors, combustion mechanisms, evolved gasses, and ash analysis of spent potlining for a hazardous waste management(Chinese Academy of Sciences, 2021) Sun, Guang; Zhang, Gang; Liu, Jingyong; Evrendilek, Deniz Eren; Büyükada, MusaAn unavoidable but reusable waste so as to enhance a more circular waste utilization has been spent potlining (SPL) generated by the aluminum industry. The combustion mechanisms, evolved gasses, and ash properties of SPL were characterized dynamically in response to the elevated temperature and heating rates. Differential scanning calorimetric (DSC) results indicated an exothermic reaction behavior probably able to meet the energy needs of various industrial applications. The reaction mechanisms for the SPL combustion were best described using the 1.5-, 3- and 2.5-order reaction models. Fluoride volatilization rate of the flue gas was estimated at 2.24%. The SPL combustion emitted CO2, HNCO, NO, and NO2 but SOx. The joint optimization of remaining mass, derivative thermogravimetry, and derivative DSC was achieved with the optimal temperature and heating rate combination of 783.5 °C, and 5 °C/min, respectively. Interaction between temperature and heating rate exerted the strongest and weakest impact on DSC and remaining mass, respectively. The fluorine mainly as the formation of substantial NaF and CaF2 in the residual ash. Besides, the composition and effect of environment of residual solid were evaluated. The ash slagging tendency and its mineral deposition mechanisms were elucidated in terms of turning SPL waste into a benign input to a circular waste utilization.Öğe Thermodynamic behaviors of Cu in interaction with chlorine, sulfur, phosphorus and minerals during sewage sludge co-incineration(Chemical Industry Press, 2018) Liu, Jingyong; Liu, Chao; Sun, Guang; Xie, Wuming; Dang, Xiao'e; Kuo, Jiahong; Chang, Kenlin; Büyükada, Musa; Evrendilek, FatihThermodynamic equilibrium calculations were performed to reveal effects of interactions among Cl, S, P and other minerals on Cu migration. Our results showed that HCl(g), SO2(g) and (P2O5)(2)(g) were released from the sewage sludge co-incineration. Cl was found to weaken adsorption of Cu by Al2O3, CaO and Fe2O3, while S delayed reactions of Fe2O3 and Al2O3 with Cu, with P having no effect on reactions between the minerals and Cu. Among the coupled systems of Cl,S and P, the co-existences of Cl and S, and Cl, S and P were determined to inhibit Cu volatilization, and the co-existence of Cl and P had an enhancing effect. Cu migration was affected only by S in the S and P system. With the SiO2, CaO and Al2O3 system, both Cl alone and Cl and P led to failed reactions between the minerals and Cu. In the systems of S, S and Cl, S and P, and S, Cl and P, the migration behavior of Cu was mainly affected by S at low temperatures and by Cl at high temperatures, whereas P had no effect on Cu migration during the entire process. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.Öğe Thermodynamic equilibrium simulations of thallium distributions in interactions with chlorine, sulfur, phosphorus, and minerals during sludge co-combustion(Springer, 2020) Liu, Jingyong; Zhang, Junhui; Sun, Guang; Büyükada, Musa; Evrendilek, Fatih; Dang, XiaoeEffects of interactions among chlorine (Cl), sulfur (S), phosphorus (P), and minerals on thallium (Tl) distributions were simulated using thermodynamic equilibrium conditions during the sludge co-combustion. Our results showed that Tl mainly existed in the forms of Tl2O3(s) and Tl(g) and did not react with SiO2, Al2O3, CaO, Fe2O3, and TiO2. Cl generated TlCl(g) and Tl(g) which in turn promoted Tl volatilization. S produced Tl2SO4(s), thus inhibiting Tl volatilization. P existence had no influence on Tl volatilization. With the couplings of Cl + S, S + P, and Cl + S + P, the reactions between single minerals and Tl were mainly controlled by S but P and Cl. With the Cl + P coupling, Cl controlled the reactions between the minerals and Tl, while P and the minerals had no significant impact. With the coupled minerals of SiO2 + CaO + Al2O3, S exerted a more influence than did Cl and P on the distributions of Tl, thus preventing Tl emissions.Öğe Thermogravimetric analysis of (co-)combustion of oily sludge and litchi peels: combustion characterization, interactions and kinetics(Elsevier Science Bv, 2018) Liu, Chao; Liu, Jingyong; Sun, Guang; Xie, Wuming; Kuo, Jiahong; Büyükada, Musa; Evrendilek, FatihThe thermal characteristics and kinetics of oily sludge, litchi peels and their blends were comprehensively evaluated using thermogravimetric experiments under air atmosphere. Results showed that devolatilization, ignition and burnout indices of litchi peels were higher than those of oily sludge, with better combustion characteristics. However, co-combustion performance decreased with increased litchi peels & action. Such interactions as inhibition effect on devolatilization and promotion effect on char oxidation of oily sludge occurred. Average activation energy was estimated at 118.1 kJ/mol for oily sludge and 215.2 kJ/mol for litchi peels using the Kissinger-Akahira-Sunose integral method and reached its minimum value with the addition of 15%-20% litchi peels. Trend of activation energy was consistent with the interaction analysis during co-combustion process. Kinetic triplets were also estimated using the integral master-plots method, while the most suitable reaction model for three stages of oily sludge and their blends was proposed.Öğe Thermogravimetric and mass-spectrometric analyses of combustion of spent potlining under N-2/O-2 and CO2/O-2 atmospheres(Pergamon-Elsevier Science Ltd, 2019) Sun, Guang; Zhang, Gang; Liu, Jingyong; Xie, Wuming; Kuo, Jiahong; Lu, Xingwen; Büyükada, Musa; Evrendilek, FatihThermal decomposition and gaseous evolution of the spent potlining (SPL) combustion were quantified using thermogravimetric and mass-spectrometric analyses in CO2/O-2 and N-2/O-2 atmospheres using three heating rates (15, 20 and 25 degrees C/min). The thermal decomposition of SPL occurred mainly between 450 and 800 degrees C. Based on the four kinetic methods of Friedman, Starink, Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa under the various conversion degrees (alpha) from 0.1 to 0.7, the lowest apparent activation energy was estimated at 149.81 kJ/mol in the 70% CO2 /30% O-2 atmosphere. The pre-exponential factor, and changes in entropy, enthalpy and free Gibbs energy were also estimated. The reaction model did not suggest a single reaction of the SPL combustion. With the alpha value of 0.25-0.7, the following function best described the reaction based on the Malek method: f(alpha) = 1/2 alpha and G(alpha) = ln alpha(2). The gases released during the combustion process included CO2, CO, NOx, HCN, and HF. (C) 2019 Elsevier Ltd. All rights reserved.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.
