Flammability limits and burning characteristics of CO–H2–H2O–CO2–N2 mixtures at elevated temperatures

• Flammability limits of (CO–H2)–O2–(H2O–CO2–N2)-mixtures were measured.
• Mixtures with a high steam content of 60% were studied.
• Effect of small H2 dilution on CO combustion was in detail investigated.
• Pressure rise rates for (CO–H2)–O2–(H2O–CO2–N2)-mixtures are presented.

The paper presents the results of an experimental evaluation of the flammability limits and maximum pressure rise rate for multi-component (CO–H2)–O2–(H2O–CO2–N2)-mixtures at elevated temperatures of 170 °C and 250 °C at ambient pressure of 1 bar. A spherical explosion chamber with a volume of 8.2 dm3 was used for the experiments. A pressure method and a high-speed camera combined with a schlieren system for flame visualization were used in this work. Flammability limits and pressure rise rates are presented for multi-component mixtures with a steam concentration of 60% and a wide variation of fuel and oxidizer concentrations in which the H2 concentrations was limited to 3%.