Valorization of Bio-Briquette Fuel by Using Spent Coffee Ground as an External Additive

The present study investigates the quality changes of wood bio-briquette fuel after the addition of spent coffee ground (SCG) into the initial feedstock materials (sawdust, shavings) in different mass ratios (1:1, 1:3). Analysis of SCGs fuel parameter proved great potential for energy generation by a process of direct combustion. Namely, level of calorific value (GCV = 21.58 MJ.kg(-1)), of ash content (Ac = 1.49%) and elementary composition (C = 55.49%, H = 7.07%, N = 2.38%, O = 33.41%) supports such statement. A comparison with results of initial feedstock materials exhibited better results of SCG in case of its calorific value and elementary composition. Bulk density rho (kgm(-3)) and mechanical durability DU (%) of bio-briquette samples from initial feedstock materials were following for sawdust: rho = 1026.39 kgm(-3), DU = 98.44% and shavings: rho = 1036.53 kgm(>-3), DU = 96.70%. The level of such mechanical quality indicators changed after the addition of SCG. Specifically, SCG+sawdust mixtures achieved rho = 1077.49 kgm(3) and DU = 90.09%, while SCG + shavings mixtures achieved rho = 899.44 kgm(-3) and DU = 46.50%. The addition of SCG increased wood bio-briquettes energy potential but decreased its mechanical quality. Consequently, the addition of SCG in wood bio-briquette has advantages, but its mass ratio plays an important key role.