Experimental analysis of the combustion behaviour of oxyfuel flames in a gas turbine model combustor

Power generation by using oxyfuel combustion in a gas turbine cycle is a promising option to reduce carbon dioxide (CO2) emission, while using fossil fuels. In order to use this process some significant changes to the gas turbine are required, regarding which open questions still exist. An important question is whether reliable operation with oxyfuel combustion under gas turbine conditions is possible. The paper describes experiments on partially premixed swirl stabilized oxyfuel flames carried out in a gas turbine model combustor at atmospheric pressure. To characterize the behaviour of the oxyfuel flames a systematic parameter study for oxidisers consisting of 20-40% oxygen (O-2), equivalence ratios from 0.5 to 1, and powers of 10-30 kW was carried out. OH*-chemiluminescence imaging was used to visualize the flame structure and stability. The results show a strong influence of the O-2 concentration on the combustion behaviour in contrast to the equivalence ratio which has only a very small effect. To obtain quantitative results, laser Raman scattering has been used on selected flames to measure simultaneously the major species concentrations, mixture fraction and temperature. The results reveal differences in the flame stabilisation mechanism, compared to methane (CH4)/air flames in the same burner. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.