Analyzing the Pyrolysis Kinetics and Pyrolysis Gases of Gassing Materials Using ReaxFF
Wang Qian1, Zhao Wanmeng1, Cao Weidong2, Shang Yi1
1. School of Sciences Xi’an University of Technology Xi’an 710048 China ; 2. State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an 710049 China;
Abstract：In recent years, the rapid development of renewable energy has posed a significant challenge to the breaking capacity of DC circuit breakers in power systems. Gas-blowing arc extinguishing technology based on gassing materials can greatly enhance the breaking capacity of DC circuit breakers. However, the macroscopic and microscopic pyrolysis mechanisms of gassing materials are unclear. Firstly, the micro-pyrolysis mechanism of typical gassing material polyamide 66 (PA66) at different pyrolysis temperatures and rates was analyzed based on the reactive force field (ReaxFF). The decomposition process of PA66 and the types and quantities of small molecule gases produced were discussed. It was found that the initial bond breaking of PA66 occurred in the C—C bond adjacent to the amide group. H2 and H2O were the main pyrolysis gases of PA66, and their production process was analyzed. The reaction rate of carbon-free small molecule gas at high temperatures accelerates, and the amount increases. The product amount with carbon atoms below four increases rapidly and decreases slightly after reaching a peak. The main reasons are the Diels-Alder reaction, C3/C4 reaction, and cyclization reaction in the unsaturated hydrocarbons in the product, which leads to the decrease of hydrocarbon molecules. The temperature increase aggravates the disintegration of the PA66 molecular chain and the formation of small molecular gas. The heating rate of the system affects the distribution of heat in the reaction system, thus affecting the formation of the product. The slower the heating rate of the system, the more conducive to the uniform distribution of heat in the reaction system. Additionally, the amount of carbon deposition during pyrolysis at 2 600 K was analyzed. Light tar was dominant, followed by heavy tar, with the least amount of coke. Subsequently, pyrolysis experiments at four different heating rates were carried out. Based on the Flynn-Wall-Ozawa isoconversional model, the average activation energy of PA66 was 194.85 kJ/mol, which was very close to the activation energy of 195.015 kJ/mol obtained by molecular dynamics simulation. Additionally, the pyrolysis gas distribution of PA66 was analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments, which verified the accuracy and reliability of the pyrolysis kinetics calculation method. PA66 is suitable for the first-order reaction kinetic model, and the simulation data have high accuracy and reliability for the thermal decomposition reaction path and gas type of PA66 at the microscale. Finally, simulation calculations and arcing experiments of three gas-producing materials, PA6, PA46, and PA66, were carried out. The gas generation rate and quantity changes during pyrolysis were observed, and the transient pressure changes during the arc-breaking experiment were analyzed. The order of transient pressure generated during the arcing process is PA6>PA46>PA66, consistent with the trend of the number of product gas molecules obtained by simulation calculation. The ReaxFF simulation results are confirmed and supplemented with the arc-breaking experiment, further verifying the reliability and accuracy of the research. This paper offers a theoretical framework for understanding the macroscopic pyrolysis behavior and the microscopic pyrolysis mechanism of gassing materials. It contributes to a deep comprehension of material behavior under high-temperature and arc conditions, laying a methodological foundation for evaluating the performance of gassing materials in DC circuit breakers.
汪倩, 赵婉萌, 曹伟东, 尚毅. 基于ReaxFF的产气材料热解及动力学分析[J]. 电工技术学报, 2025, 40(10): 3082-3096.
Wang Qian, Zhao Wanmeng, Cao Weidong, Shang Yi. Analyzing the Pyrolysis Kinetics and Pyrolysis Gases of Gassing Materials Using ReaxFF. Transactions of China Electrotechnical Society, 2025, 40(10): 3082-3096.
[1] 张玉莹, 曾博, 周吟雨, 等. 碳减排驱动下的数据中心与配电网交互式集成规划研究[J]. 电工技术学报, 2023, 38(23): 6433-6450. Zhang Yuying, Zeng Bo, Zhou Yinyu, et al.Research on interactive integration planning of data centers and distribution network driven by carbon emission reduction[J]. Transactions of China Electrotechnical Society, 2023, 38(23): 6433-6450. [2] 张照资, 高偲智, 汪倩, 等. 自触型低压混合式直流断路器系统设计与开断特性研究[J]. 中国电机工程学报, 2024, 44(11): 4544-4556. Zhang Zhaozi, Gao Caizhi, Wang Qian, et al.System design and breaking characteristics research of self- triggered low voltage hybrid DC circuit breaker[J]. Proceedings of the CSEE, 2024, 44(11): 4544-4556. [3] 束洪春, 邵宗学, 旷宇. 基于改进型限流混合式直流断路器的开断时序优化研究[J]. 电工技术学报, 2023, 38(22): 6176-6187. Shu Hongchun, Shao Zongxue, Kuang Yu.Research of opening timing optimization based on improved current-limiting hybrid DC circuit breaker[J]. Transa- ctions of China Electrotechnical Society, 2023, 38(22): 6176-6187. [4] Yin Jianning, Wang Qian, Li Xingwen, et al.Experi- mental evaluation of outgassing characteristics of polymers on air arc behavior[C]//2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM), San Antonio, TX, USA, 2020: 15-19. [5] Huo Jindong, Selezneva S, Jacobs L, et al.Study of wall ablation on low-voltage arc interruption: the effect of stefan flow[J]. Journal of Applied Physics, 2019, 125(21): 213302. [6] 谢从珍, 李彦丞, 杜岩, 等. 基于磁流体动力学的35 kV自脱离防雷装置灭弧仿真[J]. 电力工程技术, 2023, 42(1): 61-69. Xie Congzhen, Li Yancheng, Du Yan, et al.Simu- lation research on arc extinguishing characteristics of 35 kV self-detaching lightning protection device based on magnetohydrodynamics[J]. Electric Power Engineering Technology, 2023, 42(1): 61-69. [7] 王巨丰, 韩力, 卢辛, 等. 基于气吹灭弧模型研究工频电弧发展及抑制机理[J]. 电测与仪表, 2021, 58(8): 104-109. Wang Jufeng, Han Li, Lu Xin, et al.Study on the development of power frequency arc and suppression mechanism based on gas-blown arc-extinguishing model[J]. Electrical Measurement & Instrumentation, 2021, 58(8): 104-109. [8] Esmaeili N, Kandola B K, Ebdon J R, et al.Com- parison of the effects of antimony trioxide and zinc, calcium and copper stannates on the thermal degra- dation of polyamide-6, 6[J]. Polymer Degradation and Stability, 2023, 214: 110402. [9] 刘贺晨, 胡如法, 刘云鹏, 等. 220 kV退役复合绝缘子芯棒整体回收再利用可行性研究[J]. 电工技术学报, 2024, 39(11): 3433-3443. Liu Hechen, Hu Rufa, Liu Yunpeng, et al.Feasibility of the overall recycling of 220 kV retired composite insulator core rods[J]. Transactions of China Electro- technical Society, 2024, 39(11): 3433-3443. [10] Piazza V, da Silva R B Jr, Frassoldati A, et al. Detailed speciation of biomass pyrolysis products with a novel TGA-based methodology: the case-study of cellulose[J]. Journal of Analytical and Applied Pyrolysis, 2024, 178: 106413. [11] Chen Haochen, Li Meijun, Liu Xiaoqiang, et al.The pyrolysis of 4, 4, 8, 10-tetramethyl decalin and the influence of molecular structures on oil thermal cracking: a ReaxFF molecular dynamics simulation and DFT study[J]. Fuel, 2024, 362: 130857. [12] 赵曼卿, 张博, 李健飞, 等. 基于分子动力学仿真的混合油中水分子扩散行为及其介电常数研究[J]. 电工技术学报, 2024, 39(3): 798-809, 900. Zhao Manqing, Zhang Bo, Li Jianfei, et al.Influence of natural ester and mineral oil blending on the diffusion behavior of water molecules and the dielectric properties[J]. Transactions of China Elec- trotechnical Society, 2024, 39(3): 798-809, 900. [13] Bae D, Kim Y, Ko E H, et al.Methane pyrolysis and carbon formation mechanisms in molten manganese chloride mixtures[J]. Applied Energy, 2023, 336: 120810. [14] 张文琦, 范晓舟, 李宇轩, 等. 基于分子动力学的芳纶/功能化碳纳米管复合材料体系热力学性能模拟[J]. 电工技术学报, 2024, 39(5): 1510-1523. Zhang Wenqi, Fan Xiaozhou, Li Yuxuan, et al.Simulation of thermodynamic properties of aramid/ functionalized carbon nanotubes composites based on molecular dynamics[J]. Transactions of China Elec- trotechnical Society, 2024, 39(5): 1510-1523. [15] Liu Yue, Hu Jiayi, Hou Hua, et al.ReaxFF reactive force field development and application for molecular dynamics simulations of heptafluoroisobutyronitrile thermal decomposition[J]. Chemical Physics Letters, 2020, 751: 137554. [16] van Duin A C T, Dasgupta S, Lorant F, et al. ReaxFF: a reactive force field for hydrocarbons[J]. The Journal of Physical Chemistry A, 2001, 105(41): 9396-9409. [17] Sun Zhen, Li Kejiang, Bu Yushan, et al.Co-pyrolysis behavior and synergistic mechanism of sub- bituminous coal and polypropylene: a ReaxFF molecular dynamics simulation[J]. Journal of the Energy Institute, 2024, 113: 101505. [18] 刘宗杰, 王威, 付珂, 等. 基于ReaxFF的聚异丁烯高温裂解机理及影响因素研究[J]. 高压电器, 2024, 60(3): 170-178. Liu Zongjie, Wang Wei, Fu Ke, et al.Study on pyrolysis mechanism and influence factor of polyisobutylene based on ReaxFF[J]. High Voltage Apparatus, 2024, 60(3): 170-178. [19] Sun Haoshan, Zhang Xiaohui, Liu Hongxi, et al.Pyrolysis and combustion reaction mechanisms of methyl palmitate with ReaxFF-MD method[J]. Computational and Theoretical Chemistry, 2024, 1231: 114446. [20] Kowalik M, Ashraf C, Damirchi B, et al.Atomistic scale analysis of the carbonization process for C/H/O/N-based polymers with the ReaxFF reactive force field[J]. The Journal of Physical Chemistry B, 2019, 123(25): 5357-5367. [21] Arash B, Thijsse B J, Pecenko A, et al.Effect of water content on the thermal degradation of amorphous polyamide 6, 6: a collective variable-driven hyper- dynamics study[J]. Polymer Degradation and Stability, 2017, 146: 260-266. [22] Sørensen T H, Cruys-Bagger N, Windahl M S, et al.Temperature effects on kinetic parameters and substrate affinity of Cel7A cellobiohydrolases[J]. Journal of Biological Chemistry, 2015, 290(36): 22193-22202. [23] 辛喆, 赵彤, 韩智云, 等. GIL中聚酯薄膜在电热作用下裂解机理的分子动力学模拟[J]. 电工技术学报, 2018, 33(22): 5196-5205. Xin Zhe, Zhao Tong, Han Zhiyun, et al.Molecular dynamics simulation of the pyrolysis mechanism of polyester films in gas insulation lines under electro- thermal stresses[J]. Transactions of China Electro- technical Society, 2018, 33(22): 5196-5205. [24] Liu Qiang, Liu Shixiang, Lü Yadong, et al.Atomic- scale insight into the pyrolysis of polycarbonate by ReaxFF-based reactive molecular dynamics simu- lation[J]. Fuel, 2021, 287: 119484. [25] Paran S M R, Vahabi H, Jouyandeh M, et al. Thermal decomposition kinetics of dynamically vulcanized polyamide 6-acrylonitrile butadiene rubber-halloysite nanotube nanocomposites[J]. Journal of Applied Polymer Science, 2019, 136(20): e47483. [26] 谢从珍, 曾磊磊, 甘永叶, 等. 基于热重红外联用的复合绝缘子芯棒热解特性研究[J]. 电工技术学报, 2018, 33(增刊1): 227-233. Xie Congzhen, Zeng Leilei, Gan Yongye, et al.Study on pyrolysis characteristics of fiber reinforced plastic rod of composite insulators based on TG-FTIR analysis[J]. Transactions of China Electrotechnical Society, 2018, 33(S1): 27 227-233.
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