Analysis of the Autoignition Process under the Industrial Partial Oxidation Conditions Using Detailed Kinetic Modeling

Abstract

In the noncatalytic partial oxidation process, autoignition of the heated premixed combustible gases is a major source of reactor damage, unstable operation, and even explosion accidents. The knowledge of the autoignition behavior is of great importance to risk assessment and loss prevention in the partial oxidation reactors. The large experimental effort could be reduced if a reliable modeling procedure is available to identify the safe operating conditions. In this work the reliability of the detailed kinetic modeling method was investigated by comparing the simulated results with the experimental data reported in the literatures. It was found that the USC II mechanism gave the best predictions on the ignition delay times for the methane/air mixtures with equivalence ratios of 3.33 and 6.67. This mechanism was used to extrapolate the ignition delay times in the industrial partial oxidation process. The effects of initial temperature and equivalence ratio on ignition delay times were also investigated. The species concentration profiles were analyzed to understand the underlying ignition chemistry. The sensitivity analysis was carried out for the identification of the main reactions affecting the autoignition process.

Modeling Study of High Temperature Pyrolysis of Natural Gas

“…One-step partial oxidation of methane has been extensively investigated, both experimentally and numerically in batch reactors, ,, flow reactors, ,− and premixed flames. − However, limited studies are present in the literature for the two-step process. High temperature pyrolysis of hydrocarbons was investigated by Ktalkherman et al, − where hydrogen and air were combusted in the first reaction zone, followed by addition of propane, LPG, or naphtha or their mixtures in the second reaction zone, to produce ethylene.…”

“…11 Therefore, in this work, the two-step HTP process is modeled for natural gas and various cracking gas compositions and the yield of acetylene, ethylene, and soot -precursors (aromatic hydrocarbons up to 2-rings) is determined. One-step partial oxidation of methane has been extensively investigated, both experimentally and numerically in batch reactors, 3,12,13 flow reactors, 5,14−17 and premixed flames. 18−21 However, limited studies are present in the literature for the two-step process.…”