Stable Combustion under Carbon Dioxide Enriched Methane blends for Exhaust Gas Recirculation (EGR)

Exhaust gas recirculation (EGR) is one of the main techniques studied over the years to enable the use of oxyfuel combustion for carbon capture and storage (CCS). However, the use of recirculated streams with elevated carbon dioxide poses different challenges from the control of the flow rates and flue stream characteristics to the suppression of unwanted instabilities during the combustion process. Therefore, this study evaluates the use of various CO2 enriched methane blends and their response towards the formation of a great variety of structures that appear in swirling flows, which are the main mechanism for combustion control in current gas turbines systems. The study uses a 100kW acoustically excited swirlstabilised burner to investigate the flow field response. The results showed improved thermal efficiency of the system with high swirl and forcing while the blend of CO2 with methane balanced the heat release fluctuation with a corresponding reduction in the acoustic amplitudes of the system for a smooth running, suggesting that certain CO2 concentrations in the fuel can provide more stable flames at a certain carbon dioxide concentration.