Energy and Chemical Comparison of Coffea arabica By-Product Pellets Under the Torrefaction Process in Siguatepeque, Honduras

Abstract

Agricultural biomass composed primarily of hemicellulose is an energy source studied under thermal processes such as torrefaction. Due to the high volume of waste generated by the coffee sector in Siguatepeque, the energetic properties and chemical composition of pellets produced from coffee husk and coffee pulp of the species Coffea arabica, referred to in this study as PEcasut and PuPEt respectively, were compared. A completely randomized design was used with two temperature variables (200 °C and 300 °C) applied for 2 hours, generating four sample groups and their respective control groups.The results, when comparing the control groups with the torrefied groups, indicate that there are significant differences for PEcasut in its energetic characteristics in HHV (+63.95%), VM (−78.23%), and FC (+98.7%). In contrast, PuPEt showed no significant differences in HHV (+5.11%) and FC (−25.3%), except for VM (+87.5%). Regarding chemical composition, variations were observed in C and N for both groups, whereas Cl was only detected in PuPEt. It is concluded that, when subjected to this process, PEcasut exhibited superior energetic and chemical characteristics compared to PuPEt, as the latter showed minimal variations despite the treatment applied.