LAUSR

Abstract Production of briquette bio-fuel is related to several aspects of densification process. The present paper deals with the relation between briquette volume density ρ (kg·m−3) and required deformation energy Ed (J). Wood, energy crop and cardboard feedstocks were compressed by a laboratory briquetting press of two diameters (40 and 65 mm); in this way six kinds of briquette samples (W40, W65, E40, E65, C40, C65) were produced. The values of compressing force F (N) and briquette volume density ρ were measured directly during feedstock densification; the deformation energy Ed was calculated subsequently. The amount of deformation energy Ed consumed within the achievement of specific briquette volume density ρ levels differed in case of all samples, the same as the maximum achieved briquette volume density ρ levels. Best results, i.e. efficiency of briquette production (the highest ρ, the lowest Ed), were achieved by cardboard samples, followed by wood and finally by energy crop samples. An overall evaluation indicated a higher production efficiency of briquette samples 40 mm in diameter and the disadvantage of the production of briquette samples with briquette volume density ρ > 1000 kg·m−3; above such level, the amount of consumed deformation energy Ed increased disproportionately sharply.