Yazar "Ding, Ziyi" seçeneğine göre listele

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    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, Wuming
    Given 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.
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    Co-pyrolysis performances, synergistic mechanisms, and products of textile dyeing sludge and medical plastic wastes
    (Elsevier, 2021) Ding, Ziyi; Liu, Jingyong; Chen, Huashan; Huang, Shengzheng; Evrendilek, Fatih; He, Yao
    This study aimed to quantify the co-pyrolysis of textile dyeing sludge (TDS) and the two medical plastic wastes of syringes (SY) and medical bottles (MB) in terms of their performances, synergistic mechanisms, and products. The pyrolysis of polyolefin plastics with its high calorific value and low ash content can offset the poor monopyrolytic performance of TDS. The synergistic mechanisms occurred mainly in the range of 400-550 degrees C. The addition of 10% SY or MB achieved the best co-pyrolysis performance with the lowest activation energy. The co-pyrolysis increased the contents of CH4 and C-H but reduced CO2 emission. The co-pyrolysis released more fatty hydrocarbons, alcohols, and cyclic hydrocarbon during but reduced the yields of ethers and furans, through the synergistic mechanisms. The addition of the polyolefin plastics made the micro surface particles of chars smaller and looser. Our results can benefit energy utilization, pollution control, and optimal operational conditions for the industrial thermochemical conversions of hazardous wastes. (C) 2021 Elsevier B.V. All rights reserved.
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    Co-pyrolytic kinetic and interaction mechanisms and products of pineapple rind and low density polyethylene
    (Elseiver, 2023) Li, Huashan; Lyu, XianJin; Xie, Wuming; Ding, Ziyi; Liu, Yong; Evrendilek, Fatih
    The complementariness of biomass residues and plastic waste may be leveraged into fuels and other chemicals via co-pyrolysis in order to decrease our dependence on fossil fuels and increase the circularity of waste streams. The co-pyrolysis of pineapple rind (PR) and low density polyethylene (LDPE) was conducted to characterize its kinetic and interaction mechanisms and products. The co-pyrolysis was best elucidated by three stages where synergistic (facilitative) and antagonistic (inhibitory) effects dominated at below and above 495 degrees C, respectively. The activation energy requirement was lower for the co-pyrolysis than the individual PR or LDPE. The lowest copyrolysis activation energy (129.17 kJ/mol) occurred with the addition of 50% LDPE. F1, F1, F2, and R2 mechanisms best described the co-pyrolytic kinetics of the blend sample with 50% LDPE at four temperatures. The co-pyrolysis inhibited the production of CO2 and promoted the formation of CH4. The production of acids, aldehydes, and ketones fell significantly during the co-pyrolysis. The variation of these compounds improved the quality of pyrolytic oils. The multi-objective optimization based on the best-fit artificial neural network pointed to the range of 550-800 degrees C and 10 degrees C/min for the co-pyrolysis of 50% LDPE and 50% PR as the optimal operational conditions. This study provided new and actionable insights into the optimization of the co-pyrolysis of fruit residues and plastic polymers.
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    Dynamic pyrolytic reaction mechanisms, pathways, and products of medical masks and infusion tubes
    (ELSEVIER, 2022) Xu, Weijie; Liu, Jingyong; Ding, Ziyi; Fu, Jiawei; Evrendilek, Fatih
    Given the COVID-19 epidemic, the quantity of hazardous medical wastes has risen unprecedentedly. This study char-acterized and verified the pyrolysis mechanisms and volatiles products of medical mask belts (MB), mask faces (MF), and infusion tubes (IT) via thermogravimetric, infrared spectroscopy, thermogravimetric-Fourier transform infrared spectroscopy, and pyrolysis-gas chromatography/mass spectrometry analyses. Iso-conversional methods were employed to estimate activation energy, while the best-fit artificial neural network was adopted for the multi-objective optimization. MB and MF started their thermal weight losses at 375.8 degrees C and 414.7 degrees C, respectively, while IT started to degrade at 227.3 degrees C. The average activation energies were estimated at 171.77, 232.79, 105.14, and 205.76 kJ/mol for MB, MF, and the first and second IT stages, respectively. Nucleation growth for MF and MB and geometrical contraction for IT best described the pyrolysis behaviors. Their main gaseous products were classified, with a further proposal of their initial cracking mechanisms and secondary reaction pathways.
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    Oxy-fuel and air atmosphere combustions of Chinese medicine residues: Performances, mechanisms, flue gas emission, and ash properties
    (Pergamon-Elsevier Science Ltd, 2022) Chen, Zhiyun; Liu, Jingyong; Chen, Huashan; Ding, Ziyi; Tang, Xiaojin; Evrendilek, Fatih
    This study aims to quantify the combustion performances, mechanisms, and ash characteristics of Chinese medicine residues (CMR) in the air and oxy-fuel atmospheres. The CMR combustion underwent water loss (<150 degrees C) and the decomposition of the main organic components (150-560 degrees C). The CMR combustion performed better in the air than 8-2/CO2-O-2 atmosphere experimentally, as was also evidenced by the joint optimization based on artificial neural network. The rising oxygen fraction of the three oxy-fuel atmospheres improved the oxy-fuel combustion performance by 76.7%. The air atmosphere led to a higher activation energy at the start (275.15 kJ/mol) and end (520.91 kJ/mol) of the main reaction, while the oxy-fuel atmosphere resulted in a higher activation energy of 400.22 kJ/mol with the conversion degree of 0.7. Its reaction mechanism followed the sequence type (Fn) and changed from F3 to F2 in the 8-2/CO2-O-2 atmosphere and from F2.4 to F2.5 in the air atmosphere and flue gas functional groups included CO2, H2O, C=O, and C-(O)H. The oxy-fuel atmosphere was more prone to slagging than the air atmosphere. The ash in the oxy-fuel atmosphere was easily formed calcium carbonate and calcium hydroxyphosphate. (C) 2021 Elsevier Ltd. All rights reserved.
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    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, Musa
    The 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.