NITROGEN AND SULFUR RELEASE DURING COAL DEVOLATILISATION AND CHAR COMBUSTION IN CONVENTIONAL AND OXY COMBUSTION CONDITIONS

Transcription

1 NITROGEN AND SULFUR RELEASE DURING COAL DEVOLATILISATION AND CHAR COMBUSTION IN CONVENTIONAL AND OXY COMBUSTION CONDITIONS G. Coraggio, G. Bonvicini, M. Faleni 1, A. Brink, O. Karlström 2, J. Hercog 3, M. Escoto de Tejada, J. Maier 4 1 Interna'onal Flame Research Founda'on, Via S.Orlando 5, 57123, Livorno, Italy 2 Åbo Akademi University, Biskopsgatan 8, FIN , Åbo Finland 3 Ins'tute of Power Engineering, Thermal Processes Department, Augustówka 36, Warsaw, Poland 4 Ins'tute of Combus'on and Power Plant Technology (IFK), University of Stu\gart, Pfaffenwaldring 23, D Stu\gart, Germany

2 2 Scope Aim Facility Experimental Results Conclusions and recommendajons

3 3 Aim To examine whether the combusjon atmosphere has an impact on the nitrogen and sulfur release behaviour during devolajlisajon and the char oxidajon stages. To produce data on release of nitrogen and sulfur from three coals in air- and oxy- fired condijons relevant to pf combusjon.

4 4 Facility Geometric characterisjcs: Total length: 4.5 m OperaJng length: 4.0 m Inner diameter: 0.15 m Number of ports: 19 OperaJng characterisjcs: HeaJng rate: K/s Temperature: C Residence Jme: ms Solid fuel flow rate: g/h Kind of tests: DevolaJlisaJon Char producjon Char oxidajon Char gasificajon

5 5 Experimental - fuels Tested coals: South African coal Sebuku Indonesian coal Piasburgh #8 coal Analyses: Proximate and uljmate ParJcle size distribujon Ash composijon Coal M a, % wt. A d, % wt. VM d, % wt. FC d, % wt. C d, % wt. H d, % wt. N d, % wt. S d, % wt. O d,diff, % wt. LCV d, MJ/kg SAC Sebuku P.no

6 6 Experimental test runs Test T, C O 2, % Residence Cme, ms DevolaJlisaJon DevolaJlisaJon DevolaJlisaJon Char producjon Char combusjon (air, oxy) Char combusjon (air, oxy) Char combusjon (air, oxy) Char combusjon (air, oxy) Char combusjon (air, oxy)

7 7 Results coal devolavlisavon Sebuku coal

8 8 Results char oxidavon 100% 100% 80% 80% conversion [- ] 60% 40% 20% 0% aircharcomb 900 3% oxycharcomb 900 3% aircharcomb % oxycharcomb % residence Cme [ms] conversion [- ] 60% 40% 20% 0% aircharcomb % oxycharcomb % aircharcomb % oxycharcomb % aircharcomb % oxycharcomb % residence Cme [ms] Sebuku coal

9 9 Results - devolavlisavon Release, [%] Sebuku Nitrogen Sulfur Hydrogen Carbon Coal conversion, [%]

10 10 Results - devolavlisavon South African Release, [%] Nitrogen Sulfur Hydrogen Carbon Coal conversion, [%]

11 11 Results - devolavlisavon Release, [%] PiOsburgh #8 Nitrogen Sulfur Hydrogen Carbon Coal conversion, [%]

12 12 Results - devolavlisavon Sebuku South African PiOsburgh # N/C S/C N/C S/C N/C S/C 0.06 H/C H/C H/C Mass raco [- ] Coal conversion [%] Coal conversion [%] Coal conversion [%]

13 13 Results - oxidavon Sebuku Release, [%] Coal conversion, [%] Nitrogen- air Nitrogen- oxy Sulfur- air Sulfur- oxy Hydrogen- air Hydrogen- oxy Carbon- air Carbon- oxy

14 14 Results - oxidavon South African 80 Release, [%] Coal conversion, [%] Nitrogen- air Nitrogen- oxy Sulfur- air Sulfur- oxy Hydrogen- air Hydrogen- oxy Carbon- air Carbon- oxy

15 15 Results - oxidavon Sebuku Release, [%] Coal conversion, [%] Nitrogen- air Nitrogen- oxy Sulfur- air Sulfur- oxy Hydrogen- air Hydrogen- oxy Carbon- air Carbon- oxy

16 16 Results - oxidavon Sebuku South African PiOsburgh #8 Mass raco [- ] N/C air N/C oxy S/C air S/C oxy H/C air H/C oxy Coal conversion [%] Coal conversion [%] Coal conversion [%]

17 17 Conclusions Nitrogen and sulfur are released at the same rate as carbon during devolajlisajon Nitrogen and sulfur are released at the same rate as carbon during char oxidajon No difference in release between air- and oxy- firing is observed

18 18 Conclusions Release of N and S can by studied indirectly by analysing the residue Release data sensijve to inijal composijon, studying elemental rajos less prone to small variajons High conversion degrees sensijve to analysis accuracy Assuming proporjonality between release rate of N and S and devolajlisajon rate is a good approximajon.

19 19 Acknowledgements The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/ ) under grant agreement n The authors acknowledge the assistance of the project coordinator (University of South Wales) and of the project partners.