BLENDING HYDROGEN WITH LPG AND METHANE IN PREMIXED AND STRATIFIED FLAMES: AN EXPERIMENTAL STUDY

Abstract

This experimental work investigates the effects of blending hydrogen into liquefied petroleum gas (LPG)/air flames and methane/air flames under different stratified mixture conditions. A laboratory scale, a swirl-stabilized burner with two annular tubes, is used to examine the stability and structure of the flames. Fully premixed fuel-air mixture are provided through an inner and outer annulus, with equivalency ratios of φ<sub>1</sub> and φ<sub>2</sub>. Two experimental scenarios are studied to understand the hydrogen blending by mass. In the first scenario, hydrogen was introduced to replace LPG in the inner stream, while in the second scenario, hydrogen replaced LPG in the outer stream. The second scenario involves optimizing the operating conditions of the burner to achieve flame stabilization with a hydrogen blend of up to 90%. The study employs direct flame imaging and simultaneously captures OH*/CH* chemiluminescence imaging. The findings reveal that in the first scenario, a flashback occurs when hydrogen replaces LPG beyond 20% in the inner stream. However, in the second scenario, no flashback is observed even when hydrogen in the outer stream replaces up to 90% of LPG. The study also reports stable flame structures for various operating conditions using chemiluminescence imaging. These results underscore the importance of fuel blending strategies and demonstrate the potential of hydrogen as a feasible alternative fuel in combustion applications.