Use of Waste Coffee Grounds and Sawdust in Briquettes Molding and Evaluation of Properties

This work involved the molding briquettes with use of powder of coffee and eucalyptus wood sawdust residues. The briquettes produced from biomass can be applied as replacements for other fuels used in boilers for industrial processes or even for heating home in cold regions, using simple equipment. In Brazil and in many countries a large amount of waste coffee grounds is produced and wasted in daily life and in soluble coffee industry. The wood sawdust is also a fairly common residue in Brazil, especially in some cities that concentrate large number of companies that process wood. Then the molding of briquettes with these solid wastes is an opportunity to reuse the waste to produce a type of fuel from renewable sources, also including aspects related to bioenergy and Cleaner Production. Thus, in the present study were molded briquettes using the powder of coffee grounds and wood sawdust in different proportions of these materials to evaluate mechanical properties of diametrical compression. Also analyzes were performed to determine the moisture, volatile matter and ash contents, besides the determination of the calorific value content (PCS). All compositions containing sawdust briquettes caused increases in mean values of maximum resistance properties diametrical compression and elastic modulus when compared to the values of these properties of briquettes molded only with the coffee grounds. The different composition of briquettes containing sawdust presented similar value of resistance to diametrical compression. Considering the calorific values (PCS), all samples showed similar results compared to the literature. The briquettes containing only coffee grounds in the composition presents results of ash, volatile contents and PCS similar to the samples containing sawdust. However, the briquettes containing only coffee grounds showed lower maximum compressive strength compared to all other also molded with sawdust briquettes.

residue; coffee; wood sawdust; briquette