Oxy-fuel combustion: Laboratory experiments and pilot scale tests

Our focus is on oxy-fuel combustion and its associated heat transfer properties, especially radiative transport. Spectral intensity measurements have been obtained in a laboratory setting as well as on a pilot scale boiler. The pilot-scale experiments utilize a boiler retrofitted for oxy-fuel that operates at a temperature ranging to over 3000 K. Due to such high temperatures, temperature measurements of the flame are not possible with probes and are instead inferred by a process called inverse radiation interpretation. Multiple operating conditions are considered while noting that the temperature profiles indicate peak temperatures ranging from 2400 K to 3200 K. Laboratory-scale dust cloud combustion studies are also performed that characterize the radiative properties and flame speed while varying the coal type, particle size and oxygen content. Laboratory flame speed and spectral intensity is seen to increase with higher levels of oxygen, higher volatile content in coals, smaller particle sizes and diluents with lower specific heats. Flame speed is seen to range between 0.8 m/s and 4.1 m/s in these experiments. Lastly, chemical equilibrium calculations are presented. Equilibrium product temperature and species were shown with varying parameters. The maximum temperature for Illinois #6 coal and an Indonesian low sulfur bituminous coal is 2954 K and 2959 K respectively.