OICC Press International Journal of Energy and Environmental Engineering 2251-6832 4 1 (December 2013) 2013 08 14 Effect of species, particle size and compacting pressure on relaxed density and compressive strength of fuel briquettes 10.1186/2251-6832-4-30 EN Stephen J Mitchual Department of Design and Technology Education, University of Education, Winneba, Kumasi Campus, Kumasi, GH Kwasi Frimpong-Mensah Department of Wood Science and Technology, Kwame Nkrumah University of Science and Technology, Kumasi, GH Nicholas A Darkwa Department of Wood Science and Technology, Kwame Nkrumah University of Science and Technology, Kumasi, GH Journal Article 2013 08 14 Abstract Densification of biomass waste materials has provided a great boost to the utilization of wood and agricultural waste for domestic and industrial fuel. However, the processes involved in the production of this fuel make it more expensive than fossil fuel. This is because densification of wood waste into fuel briquettes is not simple. This paper reports the results of research conducted to determine the effect of species, particle size and compacting pressure on relaxed density and compressive strength in cleft of briquettes produced from sawdust of tropical hardwoods. Briquettes were made using a laboratory hydraulic press. Compacting pressure was varied from 10 to 50 MPa at an interval of 10 MPa. Species used were Triplochiton scleroxylon , Ceiba pentandra , Aningeria robusta , Terminalia superba , Celtis mildbreadii and Piptadenia africana . The results indicate that species, compacting pressure and particle size of sawdust at 5% level of significance have significant effect on the relaxed density and compressive strength in cleft of briquettes produced. The multiple correlation coefficient ( R ) and adjusted R 2 for the regression model between relaxed density of briquettes, and species density, particle size and compacting pressure were 0.93 and 0.87, respectively. Additionally, the multiple correlation coefficient and adjusted R 2 for the regression model between compressive strength of briquettes, and species density, particle size and compacting pressure were 0.83 and 0.69, respectively. The regression models suggest that species density, particle size and compacting pressure are good predictors of relaxed density and compressive strength in cleft of briquettes produced from sawdust of tropical hardwoods.