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

Abstract

Power generation by using oxyfuel combustion in a gas turbine cycle is a promising option to reduce carbon dioxide (CO 2 ) 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 partiallypremixed 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 kW to 30 kW was carried out. OH * -chemiluminescence imaging was used to visualise the flame structure and stability. The results show a strong influence of the O 2 concentration on the combustion behavior 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 simulta- neously the major species concentrations, mixture fraction and temperature.The results reveal differences in the flame stabilisation mechanism, compared to methane (CH 4 )/air flames in the same burner.

Carbon dioxide diluted methane/oxygen combustion in a rapidly mixed tubular flame burner

“…The mixing time is estimated based on the previous study [10]. For conventional oxy-fuel combustion of methane, the operating oxygen mole fraction is usually above 0.21 [8,[17][18][19], since it is difficult to establish the stable combustion owing to very low burning velocity [20] and also low flame temperature. In this study to their extinction limits, and hence, incomplete combustion may occur.…”

“…Amato et al [7] numerically investigated oxy-fuel combustion of methane, and in addition, experimentally measured CO and O 2 emissions with using a swirl stabilized combustor, to discuss the dependence of the CO and O 2 emissions on stoichiometry, pressure, CO 2 dilution and residence time. Using also a swirl type burner (DLR dual swirl burner), Kutne et al [8] experimentally investigated oxy-fuel combustion of methane and reported that stable combustion can be obtained in a limited range of oxygen mole fraction between 0.23 and 0. 4. In most oxy-fuel combustion of methane, the oxygen mole fraction is limited less than 0.5.…”

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

“…However, optimizing the mixing enables to stabilize turbulent flames with lower oxygen content in the oxidizer. For instance, Kutne et al [10] stabilized oxy-fuel flames with contents as low as 20 % oxygen in the oxidizer by using swirl and partial premixing. The choice of using a coflow in the present study has been motivated by the interest in observing how the turbulent mixing is characterized in CO 2 -diluted oxy-fuel flames.…”

Micro Gas Turbine Combustor Performances in CO2/O2 Oxidizer Atmosphere

“…They verified an improved stability for a lower content with a broadening of the flammability limits and a narrower reaction zone. Kutne et al (2011) characterized experimentally a partially premixed swirled gas turbine combustor in oxy-combustion atmospheric conditions. Their parametric studies, for a O2 concentration in the range 20-40 % and an equivalence ratio in the range 0.5-1, showed that the combustor behavior is strongly influenced by the O2 concentration, which has to be larger than 30 % and is very little affected by the equivalence ratio.…”