Diseño y construcción de un modelo de máquina para la fabricación de briquetas a partir de residuos de café (borra), para estudio de su poder calorífico como posible sustituto del carbón vegetal.

Abstract

It is designed and built a model of briquetting machine for the elaboration of briquettes from coffee residue (lees) with the objective to calculate the caloric power for comparing with the heat power of vegetal charcoal like a possible substitute of the same. For the study and previous design of the briquetting machine were investigated the briquetting processes and the briquetting existent in the market, obtaining like a better alternative the semi-industrial process, the same that is adapted to the settled requirements, for its design the methodology of conceptual design, which points the routes for the machine design, to this methodology were added specific methods like: the house of quality, functional analysis and morphological matrix, calculation of machine structure, selection of pneumatic components, etc. The most of the machine is built in structural steel material that fulfils the function for the machine is created. Once obtained the lees of coffee briquettes was carried out the heat power test through the calorimetric bomb and by the energy equation method of food for which it is necessary to do a bromatological analysis the same that was done by the petroleum, Energy and Contamination Department of Universidad Central from Ecuador, and in the lab of CESTTA of Facultad de Ciencias from ESPOCH respectively, also humidity and volatile ashes percentages were obtained, all those tests were done to the briquettes in order to determine if the same fulfil with the established requirements in the Colombian standard NTC 2060, because in our country there is no a standard related to the briquettes elaboration. Finally, a study about the amount of raw material of coffee residue in the city of Riobamba was carried out. As a result, a gross heat value of 17.62 MJ/kg was obtained, being the theoretical value, confirming with this result that it can be a substitute for vegetal charcoal since it will be used in the generation of heat energy, it is suggested that for obtaining more efficient briquettes, the use of higher pressure and temperature in the compaction process of the same.