INFLUENCE OF EXHAUST GAS RECIRCULATION ON COMBUSTION INSTABILITIES IN CH_4 AND H_2/CH_4 FUEL MIXTURES

摘要

This paper evaluates the impact of two strategies for reducing CO_2 emissions on combustion instabilities in lean-premixed combustion. Exhaust gas recirculation can be utilized to increase the concentration of CO_2 in the exhaust stream improving the efficiency in the post-combustion separation plant. This coupled with the use of coal derived syngas or hydrogen augmented natural gas can further decrease CO_2 levels released into the environment. However, changes in fuel composition have been shown to alter the dynamic response in lean-premixed combustion systems. In this study, a fully premixed, swirl stabilized, atmospheric burner is operated on various blends of H_2/CH_4 fuels with N_2 and CO_2 dilution to simulate EGR. Acoustic pressure and velocity, and global heat release measurements were performed at fixed adiabatic flame temperatures to evaluate the impact of fuel composition and dilution on various mechanisms that drive the instabilities.