Publications

Effect of syngas composition on emissions from an idealized gas turbine combustor

Williams, T.C.; Shaddix, Christopher R.; Schefer, Robert W.

Future energy systems based on gasification of coal or biomass for co-production of electrical power and gaseous or liquid fuels may require gas turbine operation on unusual fuel mixtures. In addition, global climate change concerns may dictate the production of a CO2 product stream for end-use or sequestration, with potential impacts on the oxidizer used in the gas turbine. In this study the operation at atmospheric pressure of a small, optically accessible swirl-stabilized premixed combustor, burning fuels ranging from pure methane to conventional and H2-rich and H2-lean syngas mixtures is investigated. Both air and CO2-diluted oxygen are used as the oxidizers. CO and NOx emissions for these flames have been determined over the full range of stoichiometrics from the lean blow-off limit to slightly rich conditions (φ ∼ 1.03). The presence of hydrogen in the syngas fuel mixtures results in more compact, higher temperature flames, resulting in increased flame stability and higher NOx emissions. The lean blowoff limit and the lean stoichiometry at which CO emissions become significant both decrease with increasing H2 content in the syngas. For the investigated mixtures, CO emissions near the stoichiometric point do not become significant until (φ > 0.95. At this stoichiometric limit, where dilute-oxygen power systems would preferably operate, CO emissions rise more rapidly for combustion in O2-CO2 mixtures than for combustion in air.