Kinetics Simulation of Ethylbenzene Pyrolysis Under Supercritical Pressure†

doi:10.7503/cjcu20131016

Abstract

Abstract:

Based on pyrolysis mechanism of ethylbenzene, QRRK/MSC algorithm codes were adopted to improve the related parameters of small molecular products under high pressure condition. It was found that the conventional reactions which were only suitable for the low pressure conditions could modified to discribe the performance at high pressure conditions. A pyrolysis mechanism of ethylbenzene containing 136 species and 626 steps was developed. The kinetics modeling was carried out under the supercritical pressure(4 MPa) and the temperatures of 700, 750 and 780 ℃, respectively. The product prediction and the reaction pathway analysis were used to describe the pyrolysis process. It was found that the gas yield and the conversion rates by simulation were consistent with the experimental ones. Contributions of production pathway and the percentage of decomposion pathway were calculated to analyze and verify the craking reactions. Furthermore, through the sensitivity analysis, the rate determing steps of the pyrolysis mechanism of ethylbenzene were verified and the key reactions in the mechanism were examined. Some main types of reactions about selected reactions were described in detail.

Key words: Ethylbenzene, Pyrolysis mechanism, Kinetics simulation, QRRK/MSC algorithm code, Pathway analysis

CLC Number:

O643

TrendMD:

LI Yingli, NING Hongbo, ZHU Quan, LI Xiangyuan. Kinetics Simulation of Ethylbenzene Pyrolysis Under Supercritical Pressure^†[J]. Chem. J. Chinese Universities, 2014, 35(3): 576.

Figures/Tables 5

Fig.1 Experimental observation(a) and modeling result(b) for gas yield of ethlybenzene

Fig.2 Experimental measurement(a) and modeling result(b) for conversion rate of ethlybenzene

Fig.3 Molar fraction of ethylbenzene, C6H5C2H3 and C2H6 vs. temperature Solid line: experimental; dashed line: modeling.

Fig.4 Decomposition pathway of ethylbenzene at 780 ℃The thickness of the arrows reflects roughly the flux rate for the pathway.

Fig.5 Sensitivity analysis of conversion of methane at 780 ℃ Sensitivity coefficient higher than 0.02.

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