Experiments With a Gas Turbine Model Combustor Firing Blast-Furnace Gas

On-site atmospheric experiments using a one-fifth-scale model combustor of the ABB gas turbine type 11N2-LBtu have been recently carried out at the Kawasaki Steel Works in Mizushima, Japan. A diffusion type burner of special design was used to match the extremely low heating value (2360 kJ/kg) and the high stoichiometric fuel/air ratio (1.6 kg/kg) of the Blast-Furnace Gas (BFG). Except for pressure, all burner inlet conditions were simulated as in the actual gas turbine. The burner demonstrated an excellent burning stability behaviour over the entire operation range and stably burned pure BFG down to an equivalence ratio of 0.25, without any supplementary fuel. Due to the low adiabatic flame temperature and slow kinetics, approximately 1 ppm NOx was measured in the exhaust gas. The chemical kinetics of NOx production and CO burnout were also calculated using a chemical kinetics code and reasonable agreement with the experimental results was obtained. In dual-fuel operation (BFG with oil, propane, or coke-oven gas) the burner also demonstrated a wide flame stability range.