Spectral radiation measurements on oxyfuel natural gas flames and flue gases: Comparison of air and oxyfuel radiation

Transcription

1 Spectral radiation measurements on oxyfuel natural gas flames and flue gases: Comparison of air and oxyfuel radiation Valentin Becher, Hartmut Spliethoff 1 st Oxyfuel Combustion Conference, Cottbus

2 Outline 1. Introduction 2. Methods 3. Results 4. Summary st Oxyfuel Combustion Conference - Valentin Becher 2

3 Gas properties for oxyfuel combustion Air combustion Oxyfuel combustion CO 2 [vol.-%] H 2 O [vol.-%] O 2 [vol.-%] N 2 [vol.-%] Emitting gases vol.-% 96.5 vol.-% H 2 O/CO Gases participate more in radiation Band overlapping behaviour changes st Oxyfuel Combustion Conference - Valentin Becher 3

4 Modelling oxyfuel gas radiation state of the art Two different approaches in literature: t Modify standard Weighted Sum of Grey Gases Model (WSGG) 3-4 equations for spectral modelling + Standard d model for gas radiation in CFD Software Implement more detailed Exponential Wide Band Model (EWB) 1 equation for each Wide Band + Calculation l of band overlapping more exact more equations than WSGG Implementation in CFD codes problematic Both models are not yet validated against experimental data from oxyfuel combustion st Oxyfuel Combustion Conference - Valentin Becher 4

5 Outline 1. Introduction 2. Methods 3. Results 4. Summary st Oxyfuel Combustion Conference - Valentin Becher 5

6 Air cooled combustion chamber Max. wall temp.: 1000 C 8 independent cooling sections 3 burners (70 kw each) Dry recycling Fuel: Natural Gas Air cooled wall Recirculation fan Flue gas Water Natural gas Oxygen Air st Oxyfuel Combustion Conference - Valentin Becher 6

7 FTIR measurement setup FTIR FTIR st Oxyfuel Combustion Conference - Valentin Becher 7

8 Outline 1. Introduction 2. Methods 3. Results 4. Summary st Oxyfuel Combustion Conference - Valentin Becher 8

9 Spectral radiation C 1100 C 1200 C /(m² µm Sr)] C Intensity [W/ C 700 C CO 2 and H 2 O CO C Wavelength [µm] st Oxyfuel Combustion Conference - Valentin Becher 9

10 Temperature profiles flue gases / after burner [ C] 1100 Gas tem mperature [ Air Oxyfuel 70% reci Distance to burner axis [mm] st Oxyfuel Combustion Conference - Valentin Becher 10

11 Spectral radiation flue gases / after burner C 1100 C 1200 C /(m² µm Sr)] C Intensity [W/ C 700 C 600 C Air combustion Oxyfuel 70% reci Wavelength [µm] st Oxyfuel Combustion Conference - Valentin Becher 11

12 Temperature profiles - burner 1300 Gas tem mperature [ C] Oxyfuel 70% reci. Air Distance to burner axis [mm] st Oxyfuel Combustion Conference - Valentin Becher 12

13 Spectral radiation burner C 1100 C 1200 C Intensity [W/ /(m² µm Sr)] C 800 C C 600 C Air combustion Wavelength [µm] st Oxyfuel Combustion Conference - Valentin Becher 13

14 Spectral radiation burner C 1100 C 1200 C Oxyfuel 70% reci. Intensity [W/ /(m² µm Sr)] C 800 C C 600 C Air combustion Wavelength [µm] st Oxyfuel Combustion Conference - Valentin Becher 14

15 Outline 1. Introduction 2. Methods 3. Results 4. Summary st Oxyfuel Combustion Conference - Valentin Becher 15

16 Conclusions and outlook Spectral measurements sucessful Interesting ti feature of µm CO 2 band: ~ 1 at x CO2 >10 vol.-% 2.7 µm band more difficult to analyse (band overlapping) With both bands is a good analysis of changed behaviour possible Next step: comparing of experiments with models st Oxyfuel Combustion Conference - Valentin Becher 16

17 Thank you for your attention! This work was carried out with a financial grant from the Research Fund for Coal and Steel of the European Community within the research project FRIENDLY COAL (RFC-CR-06007) st Oxyfuel Combustion Conference - Valentin Becher 17