Study on oxidation and pyrolysis of carbonate esters using a micro flow reactor with a controlled temperature profile. Part II: Chemical kinetic modeling of ethyl methyl carbonate
Study on oxidation and pyrolysis of carbonate esters using a micro flow reactor with a controlled temperature profile. Part II: Chemical kinetic modeling of ethyl methyl carbonate
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DOI：
10.1016/j.combustflame.2021.111878
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发表时间：
2021-11
影响因子：
4.4
通讯作者：
Shintaro Takahashi;Keisuke Kanayama;Shota Morikura;H. Nakamura;T. Tezuka;K. Maruta
中科院分区：
文献类型：
--
作者：
Shintaro Takahashi;Keisuke Kanayama;Shota Morikura;H. Nakamura;T. Tezuka;K. Maruta
碳酸甲乙酯 (EMC) 广泛用作锂离子电池 (LIB) 中的电解质溶剂，但人们对它的反应性知之甚少。需要更好地了解 EMC 的反应性及其化学动力学，以评估 LIB 的火灾风险。在大气压和最大壁温 (Tw,max) 为 1300 K 的微流反应器中，使用弱火焰研究了化学计量 EMC/空气混合物的反应性。为了研究 EMC 氧化（当量比为 0.5、1.0 和 1.5）和热解中形成的物种演化，在大气压和 Tw,max 范围内的 MFR 中进行了物种测量。 700–1300 K。这些实验见解用于 EMC 化学动力学机制的建模和验证。 EMC 的第一个化学动力学机制是根据碳酸二甲酯 (DMC) 和碳酸二乙酯 (DEC) 的反应以及文献数据开发的。目前的 EMC 机制很好地再现了测量的物种分布。实验和计算均显示 CO2 摩尔分数的两阶段增加：初始燃料分解产生 CO2atTw,max= 850 K，随后 CO 氧化为 CO2atTw,max= 1050 K。在第一个 CO2 增加区域，EMC 的一系列分解反应通过甲酸甲酯产生 CO2、C2H4 和 CH3OH。 CH3OH和C2H4的氧化在第二次CO2增加对应的区域进行。该EMC机构也很好地再现了实验中EMC的弱火焰位置。 EMC的计算弱火焰结构表明了三阶段反应：EMC分解、分解产物氧化为CO以及CO氧化为CO2。由燃料分解反应引发的三阶段反应不同于由普通碳氢化合物的低温氧化引发的三阶段反应。对于具有两个乙基的 DEC，也观察到了这种新颖的三阶段反应。
Little is known on reactivity of ethyl methyl carbonate (EMC), which is widely used as an electrolyte solvent in lithium-ion batteries (LIB). A better understanding on the reactivity of EMC and its chemical kinetics are required to assess the fire risks of LIB. The reactivity of a stoichiometric EMC/air mixture was investigated with a weak flame in a micro flow reactor with a controlled temperature profile (MFR) at atmospheric pressure and a maximum wall temperature (Tw,max) of 1300 K. To investigate species evolution formed in EMC oxidation (equivalence ratios of 0.5, 1.0 and 1.5) and pyrolysis, species measurements were performed in MFR at atmospheric pressure andTw,maxrange of 700–1300 K. These experimental insights were used for modeling and validation of a chemical kinetic mechanism for EMC. The first chemical kinetic mechanism of EMC was developed based on reactions of dimethyl carbonate (DMC) and diethyl carbonate (DEC), and literature data.The present EMC mechanism reproduced measured species profiles well. Both experiments and computations showed two-stage increases in CO2mole fraction: initial fuel decomposition producing CO2atTw,max= 850 K and subsequent CO oxidation to CO2atTw,max= 1050 K. In the first CO2increase region, a series of decomposition reaction of EMC produced CO2, C2H4and CH3OH via methyl formic acid. The oxidation of CH3OH and C2H4proceeded in the region corresponding to second CO2increase. The present EMC mechanism also reproduced experimental weak flame position of EMC well. Computational weak flame structure of EMC indicated a three-stage reaction: EMC decomposition, oxidation of decomposition products to CO and oxidation of CO to CO2. The three-stage reaction initiated by fuel decomposition reaction is distinct from the one initiated by low-temperature oxidation of ordinary hydrocarbons. This novel three-stage reaction was also observed for DEC, which has two ethyl groups.