Abstract: A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation (POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach. Two most widely-used rapid mixing configurations, i.e. the jet-in-cross-flow (JICF) and impinging flow configurations, are compared in terms of mixing and quenching performances using computational fluid dynamics (CFD) coupled with detailed reaction mechanism Leeds 1.5. The mixedness, residence time distribution, temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied. The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF. However, the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow. The loss ratio of acetylene in the quenching process is 2.89% for the JICF and 1.45% for the impinging flow, showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.

Key words: Jet-in-cross-flow, Impinging flow, CFD simulations, Mixing behavior, Quenching of partial oxidation process

摘要： A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation (POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach. Two most widely-used rapid mixing configurations, i.e. the jet-in-cross-flow (JICF) and impinging flow configurations, are compared in terms of mixing and quenching performances using computational fluid dynamics (CFD) coupled with detailed reaction mechanism Leeds 1.5. The mixedness, residence time distribution, temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied. The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF. However, the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow. The loss ratio of acetylene in the quenching process is 2.89% for the JICF and 1.45% for the impinging flow, showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.

关键词: Jet-in-cross-flow, Impinging flow, CFD simulations, Mixing behavior, Quenching of partial oxidation process