Briquetting and combustion of spring-harvested reed canary-grass: effect of fuel composition

Abstract

The purpose of this study was to increase the understanding how spring-harvested reed canary-grass briquettes with various chemical compositions with respect to ash content influence the formation of emissions during combustion in a 180 kW burner. Furthermore, an objective was to investigate possible ash problems during the combustion. Five fuels were used in the study consisting of three reed canary-grass samples with different ash contents from different growing sites in Sweden and additionally one of these materials was separated into a stem and leaf fraction. Flue gas emissions were measured and fuels and ashes were analysed. The variation in ash content did not affect the production of briquettes. Further, fuel containing only stem fraction showed the highest mechanical strength. The variation in ash content did not effect the flue gas emissions. The presented results showed low mean values for carbon monoxide ( <42 mg/ MJ , except one experiment) and particles in the flue gas (<150 mg/ Nm 3) (no purification of flue gas). Emissions of nitrogen oxides were <110 mg/ MJ . The ash formed light voluminous big chunks where small parts showed a tendency to be sintered. The combustion experiments imply that spring-harvested reed canary-grass can be burned with success in combustion equipment that is designed for the differences in ash content.