Effects of Partial Pressure of Oxygen on the Stability of Axial, Oxy- Coal, Turbulent Diffusion Flames

2 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Unites States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. 3 ABSTRACT Oxy-fuel combustion of pulverized coal with flue gas recirculation is potentially one of the few technologies that may allow CO 2 sequestration technologies to be applied to existing coal-fired boilers. One issue of interest is to understand and predict the effects of the near-burner zone environment consisting of O 2 and CO 2 (instead of N 2). The purpose of this research is to better understand the effect of partial pressure of O 2 (P O2) on flame stability, which becomes another degree of freedom not present during air combustion. The data obtained were designed to form an experimental basis for validation of coal-jet ignition models. These models can play a useful role in predicting flame attachment and flame stability for retrofit of oxy-coal combustion into existing boilers. Type 0 axial flames, which can be accurately characterized, are chosen to represent the near-burner zones of tangentially fired furnaces or cement kilns, where burner swirl is absent. This topical report describes:  the design attributes of a 100 kW test oxy-fuel combustor, together with an ancillary O 2 and CO 2 supply system. One challenge that was satisfactorily resolved was the steady feeding of 2 – 5 kg/hr coal into an axial burner to produce Type 0 axial turbulent diffusion flames in a steady enough fashion to allow quantification of the data.  the methodology developed to quantify flame stand-off distance, flame length, and flame luminosity using image processing techniques.  the results showing the effect of P O2 in secondary O 2 /CO 2 stream on flame stability, flame length and flame luminosity at the …