Quantitative measurements of HO2/H2O2 and intermediate species in low and intermediate temperature oxidation of dimethyl ether
Quantitative measurements of HO2/H2O2 and intermediate species in low and intermediate temperature oxidation of dimethyl ether
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DOI：
10.1016/j.proci.2014.05.120
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
N. Kurimoto;B. Brumfield;Xueliang Yang;Tomoya Wada;P. Diévart;G. Wysocki;Y. Ju
中科院分区：
文献类型：
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作者：
N. Kurimoto;B. Brumfield;Xueliang Yang;Tomoya Wada;P. Diévart;G. Wysocki;Y. Ju
作为表征碳氢化合物低温着火的两个重要物种，在常压流动反应器中，首次采用相同的实验条件，对二甲醚（DME）氧化过程中中的HO 2和H2 O2的生成进行了定量研究.采用双调制法拉第旋光光谱（DM-FRS）和分子束质谱（MBMS）分别测定了H2 O2和HO 2。DME和其他重要的中间物种，如CH 2 O和CO也测量MBMS之间的400和1150 K在不同的燃料浓度。在反应器中的物种配置文件计算通过使用零维和二维计算与不同的详细动力学交叉验证和实验结果的比较。该模型预测充分的低和中间氧化温度窗口附近600和1000 K，分别。然而，这两个模型过度预测的DME消费以及CO，HO 2和H2 O2的形成在低温氧化窗口的四个以上的因素。此外，虽然该模型预测合理，以及在中温氧化窗口的CH 2 O和CO/CO2的形成，H2 O2的浓度也被高估，这表明在DME低温化学和H2 O2化学在中温存在很大的不确定性。此外，为了分析低温化学的不确定性，使用测量的DME、CH 2 O和CO浓度导出QOOH分解为CH 2 O的分支比。QOOH分解的建模和测量的分支比之间的巨大差异表明在当前DME模型中低估了QOOH分解形成CH 2 O的速率。
As two of the most important species that characterize hydrocarbon low temperature ignition, HO2and H2O2formation during dimethyl ether (DME) oxidation was quantified using the same experimental conditions, for the first time, in an atmospheric flow reactor at low and intermediate temperature range. Dual-Modulation Faraday Rotation Spectroscopy (DM-FRS) and Molecular Beam Mass Spectrometry (MBMS) were used to measure HO2and H2O2respectively. DME and other important intermediate species such as CH2O and CO are also measured by MBMS between 400 and 1150 K at different fuel concentrations. Species profiles in the reactor were calculated by using both zero- and two-dimensional computations with different detailed kinetics for cross-validation and comparison with experimental results. The models predict adequately the low and intermediate oxidation temperature windows near 600 and 1000 K, respectively. However, both models over-predicted the DME consumption as well as CO, HO2and H2O2formations at the low temperature oxidation window by more than a factor of four. Moreover, although the model predicted reasonably well the formation of CH2O and CO/CO2at the intermediate temperature oxidation window, the concentration of H2O2was also over-predicted, suggesting the large uncertainties existing in the DME low temperature chemistry and in H2O2chemistry at intermediate temperature. Furthermore, to analyze the uncertainty of the low temperature chemistry, a branching ratio of QOOH decomposition to CH2O was derived using measured DME, CH2O and CO concentrations. The large difference between the modeled and measured branching ratios of QOOH decomposition suggests an underestimated QOOH decomposition rate to form CH2O in the current DME models.