TY - JOUR
T1 - Measurement of reaction rate constants using RCM
T2 - A case study of decomposition of dimethyl carbonate to dimethyl ether
AU - Zhang, Peng
AU - Li, Shuang
AU - Wang, Yingdi
AU - Ji, Weiqi
AU - Sun, Wenyu
AU - Yang, Bin
AU - He, Xin
AU - Wang, Zhi
AU - Law, Chung King
AU - Zhang, Feng
N1 - Funding Information:
This work is supported by the National Natural Science Foundation of China (91541113, 91541112). The authors acknowledge helpful discussions with Can Huang and Tanjin He of Tsinghua University.
Publisher Copyright:
© 2017 The Combustion Institute
PY - 2017
Y1 - 2017
N2 - This paper proposes a method to measure the reaction rate constants in kinetically-simple pyrolysis systems using rapid compression machine (RCM) and fast sampling. The method involves first performing sensitivity analysis based on a reasonable kinetic model to identify the species dominated by a target reaction. Then the time-resolved species concentration profiles are measured in RCM experiments using fast sampling and gas chromatography. Finally, the pre-assigned pre-exponential factor and the activation energy are optimized by an iterative fitting procedure, in which the entire temperature profile derived from the pressure history is taken into account. In order to validate this method, the rate constant of the reaction CH3OCHO (methyl formate, MF) => CH3OH + CO (R1) was determined by measuring the CO concentration over 948–1112 K at 30 bar, obtaining the rate expressionkR1/s−1=3.04×1013exp(−30968K/T), which is consistent with previous theoretical and experimental studies. The rate constant of the reaction CH3OCOOCH3 (dimethyl carbonate, DMC) => CH3OCH3 (dimethyl ether, DME) + CO2 (R2) was then studied by measuring the time-resolved DME concentration over 994–1068 K at 30 bar. The measured rate expression of kR2/s−1=2.02×1013exp(−34248K/T)with an uncertainty of ±30% agrees well with the RRKM/Master Equation calculation based on a high-level quantum chemical potential energy surface.
AB - This paper proposes a method to measure the reaction rate constants in kinetically-simple pyrolysis systems using rapid compression machine (RCM) and fast sampling. The method involves first performing sensitivity analysis based on a reasonable kinetic model to identify the species dominated by a target reaction. Then the time-resolved species concentration profiles are measured in RCM experiments using fast sampling and gas chromatography. Finally, the pre-assigned pre-exponential factor and the activation energy are optimized by an iterative fitting procedure, in which the entire temperature profile derived from the pressure history is taken into account. In order to validate this method, the rate constant of the reaction CH3OCHO (methyl formate, MF) => CH3OH + CO (R1) was determined by measuring the CO concentration over 948–1112 K at 30 bar, obtaining the rate expressionkR1/s−1=3.04×1013exp(−30968K/T), which is consistent with previous theoretical and experimental studies. The rate constant of the reaction CH3OCOOCH3 (dimethyl carbonate, DMC) => CH3OCH3 (dimethyl ether, DME) + CO2 (R2) was then studied by measuring the time-resolved DME concentration over 994–1068 K at 30 bar. The measured rate expression of kR2/s−1=2.02×1013exp(−34248K/T)with an uncertainty of ±30% agrees well with the RRKM/Master Equation calculation based on a high-level quantum chemical potential energy surface.
KW - Dimethyl carbonate
KW - Fast sampling
KW - Methyl formate
KW - Rapid compression machine
KW - Rate constant measurement
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U2 - 10.1016/j.combustflame.2017.05.006
DO - 10.1016/j.combustflame.2017.05.006
M3 - Article
AN - SCOPUS:85019379951
SN - 0010-2180
VL - 183
SP - 30
EP - 38
JO - Combustion and Flame
JF - Combustion and Flame
ER -