Kinetic studies of ozone assisted low temperature oxidation of dimethyl ether in a flow reactor using molecular-beam mass spectrometry
Kinetic studies of ozone assisted low temperature oxidation of dimethyl ether in a flow reactor using molecular-beam mass spectrometry
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DOI：
10.1016/j.combustflame.2016.08.008
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发表时间：
2016-11
影响因子：
4.4
通讯作者：
Hao Zhao;Xueliang Yang;Y. Ju
中科院分区：
文献类型：
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作者：
Hao Zhao;Xueliang Yang;Y. Ju
采用分子束质谱（MBMS）进样技术，在常压流动反应器中，研究了二甲醚（DME）/O3/O2/He/Ar混合气体中400 ~ 750 K范围内的臭氧辅助低温氧化反应。臭氧的摩尔分数从0到0.146%的混合物中变化，以研究其对DME氧化的增强动力学效应。DME，O2，O3，CH 2 O，H2 O2，CO，CO2和CH 3 OCHO的摩尔分数被定量为温度的函数，在一个固定的总体积流量。实验结果表明，臭氧的存在大大提高了二甲醚的低温氧化。使用现有动力学模型（Kurimoto模型（KM）（Kurimoto等人，2015）、Burke模型（BM）（Burke等人，2015）和Wang的模型（WM）（Wang等人，2015）），臭氧子机制显着高估了二甲醚氧化。DME，CH 2 O，O2和CH 3 OCHO摩尔分数的模型和实验之间观察到的巨大差异表明，有很大的不确定性的分支比的两个竞争链增长和链分支反应对涉及CH 3 OCH 2 O2和CH 2 OCH 2 O2 H自由基在低温下。
The ozone assisted low temperature oxidation chemistry of dimethyl ether (DME) from 400 K to 750 K has been investigated in the mixture of DME/O3/O2/He/Ar in an atmospheric-pressure flow reactor coupled with the molecular beam mass spectrometry (MBMS) sampling technique. The mole fraction of ozone was varied from 0 to 0.146% in the mixture to study its enhanced kinetic effect on DME oxidation. The mole fractions of DME, O2, O3, CH2O, H2O2, CO, CO2, and CH3OCHO were quantified as functions of temperature at a fixed total volumetric flow rate. The experimental results revealed that the presence of ozone dramatically enhances the low temperature DME oxidation. Numerical simulations using the existing kinetic models (Kurimoto's model (KM) (Kurimoto et al., 2015), Burke's model (BM) (Burke et al., 2015), and Wang's model (WM) (Wang et al., 2015)) with an ozone sub-mechanism over-predicted the DME oxidation significantly. The observed large discrepancies between models and experiments for DME, CH2O, O2and CH3OCHO mole fractions suggested that there were large uncertainties in the branching ratios of two competing chain-propagation and chain-branching reaction pairs involving CH3OCH2O2and CH2OCH2O2H radicals at low temperature.