Yazar "Chen, Huashan" seçeneğine göre listele

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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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    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.