Effect of swirl on fuel variability in gas turbine combustors.

摘要

Integrated gasification combined cycle (IGCC) systems have continued to be effective and persistent in the power generation world to explore low calorific value (LCV) fuel flexibility with low pollutant emissions by method of lean combustion. The major parameters that aid to bridge lean combustion and LCV fuel flexibility is to understand the effect of swirl flows. Swirl, a major design factor in the primary zone of combustor is introduced into the premixed burner to understand the performance of flow-mixing characteristics, flame stability and emissions produced by the lean premixed swirl burner (LPSB) using variable LCV fuel composition. Two swirls with vane angles, 30 degrees and 45 degrees are fabricated and their flow characteristic on LPSB is initially analyzed in terms of velocity and turbulence intensity profiles using hot-wire anemometry. These profiles are studied for better understanding of flame stability limits while combusting LCV fuel compositions. As observed in earlier researches, results demonstrated that swirls with greater (degree) vane angles showed a wider flow region indicating more stable combustion conditions. The test-matrix comprised of sixteen fuel blend compositions of methane, propane, ethane, carbon monoxide, hydrogen and natural gas. The detailed analysis provides the flame blow-off limits and emissions data obtained for a total of twenty four swirl/fuel combinations. Emissions measured by gas analyzer demonstrated that higher degree of swirls enhanced lean combustion processes and reduced major pollutant emissions, NOx and CO. Overall analysis of research shows that LCV fuels show extensive performance and can replace natural gas to produce energy efficiently in land based power generation systems.