Liquefied Natural Gas (LNG) has become an increasingly important world energy resource and is a part of the European Union clean fuel strategy launched in 2013. Therefore, there are currently several ongoing measurement strategies considering quality specification of LNG. In this context, for application in gas engines, it is essential to understand the combustion behavior of these natural gas mixtures. The methane number (MN) which represents a scale for the knocking propensity, is one of the main indicators for this combustion behavior. In this study, we investigated the influence of the LNG composition on the ignition delay time and thus the knocking behavior of prototypical LNG Mixtures. Several LNG typical mixtures containing CH/CH/CH/n-CH/i-CH/n-CH/i-CH/N were studied in the temperature range 850–1450 K, with pressures of 20 and 40 bar and at equivalence ratios of 0.4 and 1.2. The use of a shock tube and a rapid compression machine facility allowed us to study the ignition behavior over a wide range of operating conditions relevant to gas engines. We report a detailed investigation of LNG autoignition with respect to temperature, pressure and equivalence ratio thereby providing crucial validation data for chemical kinetic models for real applications.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-19
Acknowledgements: This work is part of the EMPRP ENG60 ’Metrological support for LNG custody transfer and transport fuel applications (LNG II)’ and of the EMPIR 16ENG09 ’Metrological support for LNG and LBG as transport fuel (LNG III)’. The EMRP and EMPIR are jointly funded by the participating countries within EURAMET and the European Union. The authors thank Bo Shu for the helpful discussions and his support to this work.