OCR Text |
Show -10 - and hence flame characteristics. However, 500/0 co-firing is probably an extreme situation, through the same burner. The investigation has demonstrated that dried sewage sludge can be fired successfully as a pulverised fuel, with or without coal addition, in a semi-industrial scale swirl stabilised burner. Stable combustion could be achieved over a wide range of operating conditions. Due to the high nitrogen content of the sewage sludge, NOx levels a t all co-firing ranges were typically higher than those achieved with pure coal firing. Possibilities exist for reducing NOx by air and/or fuel staging. However, NOx reduction possibilities should be studied further. The propensity for slagging requires that this problem be addressed and solutions identified prior to an application. Acknowledgements: The work describe in this progress report was executed within: • Annex II of the International Energy Agency, Coal Combustion Sciences Programme, supported by organisations in Canada, Germany, Netherlands and the United Kingdom. • The European Commission's APAS Clean Coal Technology programme. The Authors would like to thank these organisations for their support. Further they would like to thank these organisations and the Joint Committee of the IFRF for permission to publish this paper. |