Black Liquor Spray Study in the Furnace

Transcription

1 Black Liquor Spray Study in the Furnace Ari Kankkunen & Pasi Miikkulainen Carl-Johan Fogelholm Laboratory of Energy Engineering and Environmental Protection P.O.Box 4400 FIN TKK Outline of presentation Objective Test arrangement Conditions in the furnace Results Observations

2 Objective Droplet size and other spray properties was measured in a test chamber earlier. Are results applicable to a furnace? Droplet size and shape was documented inside a furnace for the firsth time * Are droplets spherical inside the furnace? * What is the relevant droplet size? * What is the velocity of the droplets? * What is the shape of the spray? Droplet size measurement inside a furnace Optics was developed to enable measurements for distances of meters Positioning system was developed Splashplate nozzle was modified to spray along furnace wall New fast cameras were adapted for measurements Tests was carried out in a pulp mill 2 flow rates and 6 spray locations was studied

3 Furnace endoscope Enables measurement of spray properties near nozzle Velocity Opening angle Sheet breakup mechanism Spray trajectory The test arrangement Measurement points Spray Modified splashplate nozzle Imaging and positioning systems Fast shutter speed cameras Furnace wall 2 m 2 m

4 The spraying angle of the modified nozzle Nozzle gun port Splashplate nozzle Spraying parameters Modified splashplate nozzle Nozzlepipediameter30 mm Softwood liquor Volume flow rates 3 and 4 l/s Dry solids content 77% Spraying temperature was C Excess temperature 15 C (above boiling point)

5 Conditions around spray Spray was directed along furnace wall The spray slightly hit the furnace wall in some tests caseses Furnace temperature was 1100 C Downwards gas flow near furnace wall Occasional burning particle flocks hit the spray Mass flow rate (mass flux) Excess temperature Test points Measurement locations (distance to nozzle) 2 m Measurement locations (distance to nozzle) 4 m 3 l/s (6.2 g/mm 2 s) 4 l/s (8.2 g/mm 2 s) 15 ºC 15 ºC Spray height 0.5 m O 15 cm above center line O Center line O 15 cm below center line Spray height 0.5 m O 15 cm above center line O Center line O 15 cm below center line Spray height 1.5 m O 57 cm above center line O Center line O 52 cm below center line Spray height 1.5 m O 57 cm above center line O Center line O 52 cm below center line

6 The test arrangement Measurement points Spray Modified splashplate nozzle Imaging and positioning systems Fast shutter speed cameras Furnace wall 2 m 2 m Example image, (2 m, 3 lps, center line) 70 mm

7 Example image, 2 m, 4 lps, center line 70 mm Example image, velocity, (2 m, 4 lps, center line) 70 mm

8 Spray at varying locations ( 2 m, 4 l/s) above center line below Spray at varying locations ( 4 m, 4 l/s) above center line below

9 Distance to nozzle 4 m, center line 70 mm 90 mm Observations Accurate imaging inside the furnace is possible Spray width and velocity can be determined Spray particles can be detected, the fraction of burning particles inside the spray can be estimated Large particles are non-spherical Problems with high particle density and changing background illumination, computer analysis is difficult Transient gas flows in the furnace make spray analysis difficult

10 Future work The image analysis system will be developed to enable semiautomatic analysis of sprays Droplet shape will be determined Droplet size will be determined Velocity will be determined Results will be published Acknowledgement TEKES Andritz Oy Kvaerner Power Oy Foster Wheeler Energy Oy Vattenfall Utveckling AB Metsä-Botnia Oy International Paper Mill Personel