Experimental Investigation and Comparison of Pulverized Coal Combustion in CO sub(2)/O sub(2)- and N sub(2)/O sub(2)-Atmospheres

• Published in: Flow, turbulence and combustion turbulence and combustion, 2016-03, Vol.96 (2), p.417-431
• Main Authors: Hees, Johannes, Zabrodiec, Diego, Massmeyer, Anna, Habermehl, Martin, Kneer, Reinhold
• Format: Article
• Language: English
• Subjects: Atmospheres; Carbon dioxide; Combustion; Flue gases; Oxy-fuel; Pulverized coal; Spontaneous emission; Turbulent flow
• ISSN: 1386-6184; 1573-1987
• DOI: 10.1007/s10494-015-9662-9

This paper presents results from measurements of flue gas components and spontaneous emission originated from excited OH-molecules of pulverized coal combustion in air- and CO sub(2)/O sub(2)-atmospheres. Measurements were conducted for various local oxygen-fuel ratios and O sub(2) contents of the CO sub(2)/O sub(2)-atmosphere. For this purpose a swirl burner (60kW sub(th)) specially designed for oxy-fuel combustion was used. In the present study, measurements in the flame of the swirl burner were performed in a vertical downward fired test furnace. A CCD-camera system was used to capture spontaneous emission of excited OH-molecules. Furthermore, the global flue gas emissions were measured in the stack to gain data for a general description of the combustion process. The measurements were performed for combustion with air and with a premixed oxy-fuel atmosphere. Two different oxy-fuel atmospheres were tested (21 vol.-% O sub(2)/ 79 vol.-% CO sub(2) and 25 vol.-% O sub(2)/ 75 vol.-% CO sub(2)). In addition the oxygen-fuel ratio in the proximity of the burner was varied between 1.0 and 0.6 while the global oxygen-fuel ratio was fixed at 1.3. Global concentrations of CO and NO in the flue gas as well as profiles of the spontaneous emission of OH-molecules are presented and discussed within this paper. Based on these measurements flame structures and flame characteristics are identified.