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Yan S, Xia D, Lai NC, Jiang B, Liu X. New insight into the synergistic reactions involved in the hydrothermal co-liquefaction of synthetic polymer wastes by molecular dynamics and DFT methods. JOURNAL OF HAZARDOUS MATERIALS 2023; 449:131032. [PMID: 36821896 DOI: 10.1016/j.jhazmat.2023.131032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Coliquefying synthetic aliphatic and aromatic polymer wastes using supercritical water has drawn considerable research attention. However, the mechanisms of chemical reactions between different types of polymers are ambiguous. Herein, depolymerization mechanisms for individual polymers and reaction mechanisms for binary polymer mixtures were investigated using molecular dynamics and density functional theory (DFT). The innovative approach showed that the production of oil from individual polymers during HTL was hindered by (1) volatile C1-C4 molecules emitted from aliphatic polymers and (2) polycyclic aromatic hydrocarbons (PAHs) produced from aromatic polymers. Interestingly, synergistic reactions among these byproducts from different polymers could promote oil production during coliquefaction. Specifically, the synergistic radical-related reactions included (1) the ring-opening of PAHs caused by C2H2 molecules emitted from aliphatic polymers and (2) the recombination of PHA branches and short-chain aliphatics. A considerable synergy between aromatic polymers with higher benzene ring contents and aliphatic polymers with lower H/C atomic ratios was observed near the critical temperature of 649 K. This work provides new insights into the synergistic reactions involved in the coliquefaction of synthetic polymers and gives useful guidance for realizing efficient oil production from mixed organic wastes.
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Affiliation(s)
- Shuo Yan
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Dehong Xia
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory for Energy Saving and Emission Reduction of Metallurgical Industry, Beijing 100083, China.
| | - Nien-Chu Lai
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Binfan Jiang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiangjun Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
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Li J, Zheng D, Yao Z, Wang S, Xu R, Deng S, Chen B, Wang J. Formation Mechanism of Monocyclic Aromatic Hydrocarbons during Pyrolysis of Styrene Butadiene Rubber in Waste Passenger Car Tires. ACS OMEGA 2022; 7:42890-42900. [PMID: 36467943 PMCID: PMC9713895 DOI: 10.1021/acsomega.2c04994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
The production of aromatic hydrocarbons from the waste tire pyrolysis attracts more and more attention because of its tremendous potential. Based on styrene-butadiene rubber (SBR), which is the main rubber in the waste passenger car tires, this work studies the temperature influence on primary pyrolysis product distribution by experimental techniques (Py-GC/MS, TG-MS), and then, the formation mechanism of monocyclic aromatic hydrocarbons (MAHs) observed in the experiment was analyzed by first-principles calculations. The experimental results show that the MAHs during the pyrolysis mainly include styrene, toluene, and xylene, and subsequent calculations showed that these compounds were formed through a series of primary and secondary reactions. The formation pathways of these typical MAHs were studied via the reaction energy barrier analysis, respectively. It shows that the MAHs were not only derived from the benzene ring in the SBR chain but also generated from short-chain alkenes through the Diels-Alder reaction. The obtained pyrolysis reaction mechanism provides theoretical guidance for the regulation of the pyrolysis product distribution of MAHs.
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Affiliation(s)
- Jiayuan Li
- Institute
of Industrial Catalysis, College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China
| | - Dahai Zheng
- Faculty
of Environment and Life, Beijing University
of Technology, Beijing 100124, China
| | - Zihao Yao
- Institute
of Industrial Catalysis, College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China
| | - Shixin Wang
- Institute
of Industrial Catalysis, College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China
| | - Ruinian Xu
- Faculty
of Environment and Life, Beijing University
of Technology, Beijing 100124, China
| | - Shengwei Deng
- Institute
of Industrial Catalysis, College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China
- Ningbo
Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Biaohua Chen
- Faculty
of Environment and Life, Beijing University
of Technology, Beijing 100124, China
| | - Jianguo Wang
- Institute
of Industrial Catalysis, College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China
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The reaction mechanism and sulfur evolution during vulcanized nature rubber pyrolysis in the atmosphere of H2O: A ReaxFF molecular dynamics study. Polym Degrad Stab 2022. [DOI: 10.1016/j.polymdegradstab.2022.110064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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